JP6442778B2 - Piston member, piston fastening structure - Google Patents

Description

  The present invention relates to a piston member that receives an external force in a linear motion system and a fastening structure of a linear rod that holds the piston member.

  There are many linear motion systems that create reciprocating motions according to the purpose, such as hydraulic cylinders, Bingham dampers, air cylinders, shock absorbers, and the like. These linear motion systems often have a piston member that receives fluid pressure and a linear rod that holds the piston member. The piston member is used to control the reciprocating motion, and the reciprocating motion is linearly moved. The power is output or reduced through the rod.

  For example, in a hydraulic cylinder or the like, a piston member and a linear rod are arranged in a cylindrical tube. The hydraulic pressure is supplied into the tube to cause the piston member to perform a desired reciprocating motion, and the motion is taken out from the linear motion rod.

  A screw is generally used for fixing the piston member and the linear rod. Specifically, a male screw is formed in the vicinity of the end of the linear motion rod, and in a state where the piston member is fitted, a female screw body is screwed into the male screw and fixed so as to sandwich the piston member. It has a structure.

  Further, when fastening the female screw body, a washer (washer) or a cushion sleeve is inserted around the linear motion rod. These members protect the piston member from buckling and scratches at the time of fastening, and conversely suppress the loosening of the screw body by positively pressing the piston member against the piston member.

  Japanese Industrial Standard JIS B 8368 Hydraulic Cylinder

  Since the external force of the working fluid is repeatedly applied to the piston member, the internal thread gradually loosens, and the piston member and the linear rod are unfastened. In order to prevent loosening of the internal thread body, the internal thread body is tightened strongly, but this is not an essential solution, and there is a problem that the piston member and the linear motion rod are likely to be subject to fatigue failure. .

  In order to prevent loosening of the female screw body, for example, a snap ring may be fitted on the outer side of the female screw body. If the snap ring is used, it is possible to prevent the female screw body from falling off from the shaft portion, but there is a problem that the female screw body cannot be prevented from loosening. Further, since the snap ring is relatively thin or thin, the snap ring is easily broken and is difficult in strength.

  In addition, in the case of a structure in which a step is formed on the linear motion rod and a piston member is brought into contact with the step and is fixed by being sandwiched by a female screw, the diameter of the linear motion rod needs to be reduced stepwise toward the shaft end. is there. As a result, the diameter of the male screw formed at the outermost end of the linear motion rod is the smallest, but all forces acting on the piston member must be received by this male screw. As a result, it becomes difficult to increase the cross-sectional area (diameter) of the male screw alone, and in order to provide a step, the body side of the linear rod must be designed to be thicker than necessary. There is a problem that the cost increases due to the accompanying increase in weight, increase in processing amount, and the like.

  SUMMARY OF THE INVENTION The present invention has been made by the inventor's earnest research in view of the above problems, and an object of the present invention is to provide a structure that improves durability with respect to fastening of a piston member and a linear rod in a linear motion system. And

The present invention that achieves the above object is accommodated in the tube so as to be movable in the axial direction, is fixed to the linear motion rod in the tube, receives the pressure of the fluid, and transmits it to the linear motion rod A seal portion that is formed on an outer peripheral surface facing the inner peripheral surface of the tube and that restricts movement of the fluid in the vicinity of the inner peripheral surface, and at least a pair of end surfaces facing the axial direction A pressure-receiving surface formed on one side for receiving the pressure of the fluid; and an insertion hole into which the linear rod is inserted. The insertion hole is threadedly engaged with a male screw portion on an outer peripheral surface of the linear rod. An internal thread portion is formed, and the insertion hole has an annular inner seal accommodation hole that is larger in diameter than the internal thread portion and continues to the end surface, and an annular inner seal is formed in the inner seal accommodation hole. Components can be placed Is, the peripheral surface of the inner seal accommodating hole, wherein the external thread portion is tapered structure small diameter and the end face side is a large diameter, a piston member.
In relation to the piston member, the outer peripheral surface has an annular outer seal fitting portion that is smaller in diameter than the seal portion and continues to the end surface. The annular outer seal member is configured to be displaceable.
In relation to the piston member, the peripheral surface of the outer seal fitting portion has a taper structure in which the seal portion side has a large diameter and the end surface side has a small diameter.
Further, the present invention that achieves the above object is accommodated in the tube so as to be movable in the axial direction, is fixed to the linear motion rod in the tube, receives the pressure of the fluid, and transmits it to the linear motion rod. A piston member that is formed on an outer peripheral surface facing the inner peripheral surface of the tube and that seals the movement of the fluid adjacent to the inner peripheral surface, and a pair of end surfaces facing the axial direction A pressure receiving surface that receives the pressure of the fluid, and an insertion hole into which the linear motion rod is inserted. The insertion hole has a male thread portion and a screw on the outer peripheral surface of the linear motion rod. A female threaded portion is formed, and the outer peripheral surface has a smaller diameter than the seal portion and has an annular outer seal fitting portion that continues to the end surface. An annular outer seal member Location capable constructed, the peripheral surface of the outer seal fitting portion, the seal portion side is characterized by a large径且one said end face a tapered structure whose diameter, is a piston member.
In relation to the piston member, an annular tapered surface for centering with the linear motion rod or the external member is formed in the insertion hole or the end surface.
In relation to the piston member, the insertion hole has an annular inner seal accommodation hole that is larger in diameter than the female screw portion and continues to the end surface. The inner seal member is configured to be arranged.
In relation to the piston member, the peripheral surface of the inner seal accommodation hole has a taper structure in which the male screw portion side has a small diameter and the end surface side has a large diameter.

  In relation to the piston member, the end face is provided with a relative rotation prevention mechanism that can engage in the circumferential direction with respect to the linear motion rod or an external member fastened to the linear motion rod. To do.

  In relation to the piston member, the relative rotation preventing mechanism has an engagement hole that houses an engagement member that engages with the linear motion rod or the external member.

  In relation to the piston member, the relative rotation preventing mechanism abuts on the linear motion rod or the external member, and relative to the linear motion rod or the external member for rotation in a direction in which the female screw portion is tightened. With respect to rotation in a direction in which the movement is allowed and the female screw portion is loosened, relative movement with the linear motion rod or the external member is restricted.

  In relation to the piston member, a piston-side cooperative region having a non-circular cross section when viewed from the axial direction is formed in the insertion hole.

  In relation to the piston member, the minimum distance from the axial center of the piston-side cooperation region is larger than the minimum distance from the axial center of the female screw portion.

  In relation to the piston member, the piston-side cooperation region is engaged with the shaft portion of the linear motion rod in the circumferential direction.

  In relation to the piston member, the piston-side cooperation region is elastically deformable in the radial direction.

  The present invention that achieves the above object is a linear motion system comprising: the piston member according to any one of the above; and the linear motion rod that holds the piston member and interlocks with a reciprocating movement of the piston member. A fastening structure of the piston member with respect to the linear rod, wherein the first male screw spiral groove and the second male screw spiral groove are formed on the linear rod and have different lead angles and / or lead directions. The first female screw formed on the male screw portion and the piston member, and having the first female screw helical groove corresponding to the first male screw helical groove, and configured to be able to be screwed into the first male screw helical groove. And a female screw body for fixing having the second female screw spiral groove corresponding to the second male screw spiral groove and configured to be able to be screwed into the second male screw spiral groove. Do It is a piston fastening structure.

  In relation to the piston fastening structure, the male screw portion is formed so that the first male screw spiral groove and the second male screw spiral groove overlap at least in a part of the region.

  In relation to the piston fastening structure, there is provided an engagement member that is simultaneously inserted into a first engagement hole formed in the piston member and a second engagement hole formed in the female screw body for fixing. A relative rotation preventing mechanism is provided that restricts relative rotation of the piston member and the female screw body for fixing by a joint member.

  In relation to the piston fastening structure, the relative rotation preventing mechanism includes an engaging female screw portion formed on an inner peripheral surface of at least one of the first engaging hole and the second engaging hole, and the engaging female screw. A male screw body for engagement that functions as the engagement member by screwing with a portion, and a washer into which the male screw body for engagement is inserted, and the male screw body for engagement is on the screw body side facing the washer The washer comprises a first receiving part facing the screw body side seat part, and a second receiving part facing the fixing female screw body or the piston member, The female screw body for fixing or the piston member has a member side seat portion facing the second receiving portion, and the screw body side seat portion is provided between the screw body side seat portion and the first receiving portion. Engage with each other even if rotational force in a specific direction acts on them A first engagement mechanism to be held is configured, and a state in which the member side seat portion and the second receiving portion are engaged with each other even if a rotational force in the specific direction acts on the washer. A second engagement mechanism to be held is configured.

  In relation to the piston fastening structure, the relative rotation preventing mechanism includes an engaging female screw portion formed on an inner peripheral surface of at least one of the first engaging hole and the second engaging hole, and the engaging female screw. An engaging male screw body that functions as the engaging member by screwing with a portion, and a member side seat formed on the fixing female screw body or the piston member. A screw body side seat portion facing the member side seat portion is provided, and a rotational force in a specific direction acts on the screw body side seat portion between the screw body side seat portion and the member side seat portion. However, it is characterized in that an engagement mechanism that holds the state of being engaged with each other is configured.

  In relation to the piston fastening structure, the relative rotation preventing mechanism is an engagement which is disposed so as to be movable in the axial direction inside the first engagement hole and the second engagement hole and functions as the engagement member. And a biasing means that is accommodated in the first engagement hole or the second engagement hole and biases the engagement pin.

  In relation to the piston fastening structure, in the shaft portion having the male screw portion, a linear motion rod in which a rod side cooperation region having a non-circular cross section when viewed from the axial direction is formed, and the male screw portion of the linear motion rod; The piston member according to any one of claims 1 to 13, wherein the rod member is a link member formed with an insertion hole through which the male screw portion can be inserted, and the rod is formed by forming the insertion hole into a non-circular shape. And a cooperating member characterized by having a relative rotation preventing mechanism engaging with the side cooperating region in the circumferential direction and engaging with the piston member in the circumferential direction.

  In relation to the piston fastening structure, the cooperation member has the relative rotation prevention mechanism with the piston member on both surfaces in the axial direction, and the piston member has both axial sides of the cooperation member. The piston member is engaged with the cooperation member in the circumferential direction.

  In relation to the piston fastening structure, in the shaft portion having the male screw portion, a linear motion rod in which a rod side cooperation region having a non-circular cross section when viewed from the axial direction is formed, and a female screw portion screwed with the male screw portion The piston member according to any one of the above, in which the piston side cooperation region having a non-circular cross section when viewed from the axial direction is formed in the insertion hole having the rod side cooperation region and the piston side cooperation The regions are structured to engage with each other in the circumferential direction while allowing relative rotation by an external force.

  In relation to the piston fastening structure, a linear motion rod having a shaft portion having a male screw portion, a piston member according to any one of claims 1 to 13 screwed with the male screw portion of the linear motion rod, and And a relative rotation preventing mechanism that is integrally formed with the shaft portion of the linear rod and engages with the piston member in a circumferential direction.

  According to the present invention, it is possible to improve the durability with respect to the fastening of a linear motion rod such as a piston rod while having a simple structure.

It is a figure which shows the fastening state of the fastening structure of the piston which concerns on 1st embodiment of this invention. It is the front view of the (A) linear motion rod of the fastening structure of the piston which concerns on 1st embodiment of this invention, (B) The bottom view of a linear motion rod. (A) Front sectional view of washer of piston fastening structure according to first embodiment of the present invention, (B) Bottom view of washer, (C) Top view of piston member, (D) Front view of piston member. . It is a figure which shows the state in the middle of fastening of the fastening structure of the piston which concerns on 1st embodiment of this invention. (A) is a fastening state figure of the piston member and washer of the fastening structure of the piston concerning a first embodiment of the present invention, and (B) thru / or (D) are the figures showing the modification. (A) thru | or (C) are the fastening state figures of the piston member and washer of the piston fastening structure which concern on the modification of 1st Embodiment of this invention. (A) thru | or (D) is the front view and bottom view of a linear motion rod of the piston fastening structure which concern on the modification of 1st Embodiment of this invention. It is a figure which shows the fastening state of the fastening structure of the piston which concerns on the modification of 1st embodiment of this invention. It is a fastening state figure of the fastening structure of the piston concerning a second embodiment of the present invention. It is the front view and bottom view of (A) linear motion rod used for the fastening structure of the piston which concerns on 2nd embodiment of this invention, (B) The bottom view of a washer. It is the side view and bottom view of (A) linear motion rod used for the fastening structure of the piston which concerns on the modification of 2nd embodiment of this invention, (B) The bottom view of a washer. (A) (B) is an exploded view of the fastening structure of the piston which concerns on the modification of 2nd embodiment of this invention. It is the (A) fastening state figure of the fastening structure of the piston which concerns on the modification of 1st embodiment of this invention, (B) exploded view. It is (A) fastening state figure and (B) exploded view of the fastening structure of the piston which concerns on the modification of 2nd embodiment of this invention. It is (A) fastening state figure and (B) exploded view of the fastening structure of the piston which concerns on the modification of 2nd embodiment of this invention. It is (A) fastening state figure and (B) exploded view of the fastening structure of the piston which concerns on the modification of 2nd embodiment of this invention. It is a fragmentary sectional view which shows the fastening structure of the piston which concerns on 3rd embodiment of this invention. It is (A) sectional drawing, (B) front view, and (C) bottom view which show the internal thread body used with the fastening structure of the piston which concerns on 3rd embodiment of this invention. (A) And (B) is the front view and bottom view which show the modification of the linear motion rod used with the fastening structure of the piston which concerns on embodiment of this invention. (A) And (B) is a fragmentary sectional view showing the modification of the fastening structure of the piston concerning the embodiment of the present invention. It is a fragmentary sectional view which shows the modification of the fastening structure of the piston which concerns on embodiment of this invention. (A) And (B) is a fragmentary sectional view showing the modification of the fastening structure of the piston concerning the embodiment of the present invention. (A) It is a top view of the fastening structure which concerns on 4th embodiment of this invention. (B) It is a front view of a fastening structure. It is AA sectional view taken on the line of Fig.23 (a). It is the figure which expanded and showed the external thread part of the linear motion rod. (A)-(d) It is the figure which showed the relative operation | movement of the piston member and the internal thread body for fixation. It is a front fragmentary sectional view which shows a relative rotation prevention mechanism. It is the front fragmentary sectional view and bottom view of the external thread body for engagement used with a relative rotation prevention mechanism. It is the top view and front fragmentary sectional view of a washer used with a relative rotation prevention mechanism. (A) is a conceptual diagram which shows the effect | action of the saw blade of a relative rotation prevention mechanism, (B)-(D) is a conceptual diagram which shows the modification of a saw blade. (A)-(C) are the conceptual diagrams which show the modification of the saw blade of a relative rotation prevention mechanism. (A) (B) is the top view and front fragmentary sectional view of a washer used by the application example of a relative rotation prevention mechanism. It is the top view and front fragmentary sectional view which show the relative rotation prevention mechanism of the fastening structure which concerns on 5th embodiment. (A) is the top view and front fragmentary sectional view of the washer used with the relative rotation prevention mechanism, (B) is the front fragmentary sectional view which shows the open | release operation | work of the relative rotation prevention mechanism. (A) is a front fragmentary sectional view showing a washer opening operation used in an application example of the relative rotation prevention mechanism, and (B) is a plan view and a front partial sectional view showing a washer opening operation used in the application example. FIG. (A) Plan view and front partial cross-sectional view of washer, (B) Front partial cross-sectional view showing a state in which the washer and the male threaded body for engagement are integrated. C) is a front partial sectional view showing a fastening state. (A) thru | or (C) are the top views which show the application example of the same relative rotation prevention mechanism, (D) is the top view and front fragmentary sectional view of the washer used by another application example. (A) The top view and front fragmentary sectional view of a washer of the relative rotation prevention mechanism of the fastening structure which concern on 7th embodiment, (B) The front fragmentary sectional view which shows a fastening state. It is (A) top view and (B) front sectional view concerning an example of application of the fastening structure. (A) Front sectional view of the fastening state of the fastening structure according to the eighth embodiment, (B) Front sectional view showing a released state of the relative rotation preventing mechanism. It is front sectional drawing of the fastening structure used as the application example of 4th to 8th embodiment. It is front sectional drawing of the fastening structure used as the other application example of 4th to 8th embodiment. It is front sectional drawing which expands and shows the external thread part of the linear motion rod of the fastening structure used as the other application example of 4th-8th embodiment. It is front sectional drawing of the fastening structure used as the other application example of 4th to 8th embodiment. It is front sectional drawing of the fastening structure of 9th embodiment. It is front sectional drawing which shows the application example of the fastening structure of 9th embodiment. It is sectional drawing which shows the basic composition of the hydraulic piston which concerns on embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. First, a basic structure of a hydraulic piston as an example of a linear motion system to which the piston fastening structure 1 of the present invention can be applied will be described with reference to FIG. The hydraulic piston includes a piston member 100 that functions as a piston, a linear motion rod 10 that functions as a piston rod, a tube 4, a rod cover 5, and a head cover 6. The piston member 100 is fixed to the linear motion rod 10 and is disposed in the cylindrical tube 4. In the tube 4, a ring-shaped rod cover 5 is disposed on the side from which the linear rod 10 protrudes, and a head cover 6 is disposed on the opposite side. Therefore, both ends of the tube 4 are covered with the rod cover 5 and the head cover 6 so that a pressure space is formed inside. Further, openings 7 and 8 through which the working fluid is taken in and out of the tube 4 are formed in the vicinity of both ends of the tube 4, and the piston member 100 is moved by flowing oil into the pressure space through the openings 7 and 8. It has a structure to let you.

  FIG. 1 shows a piston fastening structure according to the first embodiment. The piston fastening structure includes a linear motion rod 10, an annular washer 50 serving as a cooperation member, and a piston member 100. A piston ring 90 is provided around the piston member 100.

  The piston member 100 is a cylindrical member, and has an annular outer peripheral surface 105 facing the inner peripheral surface of the tube 4, a pair of end surfaces 101 facing in the axial direction, and an insertion formed coaxially with the outer peripheral surface. It has a hole 100a. The outer peripheral surface 105 approaches the inner peripheral surface of the tube 4 and serves as a seal portion 105a that restricts the movement of the working fluid. At least one of the end surfaces 101 (here, both) serves as a pressure receiving surface 101a that receives the pressure of the working fluid. The linear motion rod 10 is inserted into the insertion hole 100a.

  As shown in FIG. 2A, the linear rod 10 has a main body 12 a and an end 12 c in the shaft portion 12. A step portion 20 is formed at the boundary between the main body portion 12a and the end portion 12c, and a rod side seat portion 22 is formed at a portion corresponding to a lower portion or a root of the step portion 20. The main body 12a has a cylindrical shape. A male screw portion 13 is formed at the end portion 12c.

  As shown in FIG. 2B, a rod-side cooperation region 17 having a non-circular cross section when viewed from the axial direction is formed at the end 12c. Here, the rod side cooperation area | region 17 is formed in the base end side rather than the external thread part 13 in the edge part 12c. Specifically, the rod-side cooperation region 17 has a shape in which a part of a circular arc with a circular cross section is omitted along the chord (which is an irregular shape). Become. As a result, the rod-side contact portion 23 becomes a plane that is perpendicular to the radial direction and directed outward in the radial direction on the peripheral surface of the end portion 12c. The rod-side contact portion 23 has a distance from the axial center of the screw that fluctuates along the circumferential direction, and the first rod-side contact region 23Y has a distance X1 along one circumferential direction X of the linear motion rod 10. X2 increases. In the second rod side contact region 23X, the distances Y1 and Y2 increase along the other circumferential direction Y of the linear motion rod 10. Note that this amount of variation is set to be the same as that of a washer-side contact portion 53 described later if a slight margin is ignored. Alternatively, the margin gap may be set so as to be filled by deformation in the direction perpendicular to the axis caused by axial compression caused by tightening of the washer 50 by the piston member 100.

  Further, the minimum radius 17Y from the axis of the rod side cooperation region 17 is set to be equal to or greater than the maximum radius 13X from the axis of the male screw portion 13. Therefore, it is preferable that the maximum radius 17Y from the axis of the rod side cooperation region 17 is set larger than the maximum radius 13X from the axis of the male screw portion 13.

  As shown in FIGS. 3A and 3B, a first receiving portion 60 is formed on one surface of the washer 50. The first receiving portion 60 faces the seat portion 102 of the piston member 100, and a first relative rotation preventing mechanism A is formed between the two. In the first relative rotation preventing mechanism A, when at least the piston member 100 tries to rotate in a loosening direction with respect to the linearly acting rod 10 to be screwed, the first receiving portion 60 and the seat portion 102 of the piston member 100 are mutually connected. Engagement prevents relative rotation between the first receiving portion 60 and the rod side seat portion 22 with respect to the rotation direction. A second receiving portion 70 is formed on the other side of the washer 50. The second receiving portion 70 faces the step portion 20 of the linear motion rod 10.

  The piston rod insertion hole 52 in the washer 50 is non-circular when viewed from the axial direction. The insertion hole 52 has a shape in which a part of the circular arc is omitted along the string, and engages with the rod-side cooperation region 17 of the linear motion rod 10 in the circumferential direction ( Defined as an auxiliary relative rotation prevention mechanism B).

  Specifically, the auxiliary relative rotation prevention mechanism B includes a washer side contact portion 53 formed in the insertion hole 52 of the washer 50 and a rod side contact portion formed in the rod side cooperation region 17 of the linear motion rod 10. 23. As described above, the insertion hole 52 of the washer 50 has a partial arc shape that is concentric with respect to the axis of the screw, and the remaining portion is cut into a straight line like a string. The string becomes the washer side contact portion 53. Accordingly, the inner wall of the insertion hole 52 of the washer 50 has a planar shape in a portion corresponding to the washer-side contact portion 53, and the distance from the screw shaft center varies along the circumferential direction. Specifically, in the first washer side contact region 53X, the distances XA and XB increase along one circumferential direction X of the washer 50. In the second washer side contact region 53Y, the distances YA and YB increase along the other circumferential direction Y of the washer 50. The portion excluding the washer-side contact portion 53 has a perfect circular shape with a constant distance from the screw shaft center. Further, the minimum radius 52Y from the axis of the insertion hole 52 is set to be equal to or larger than the maximum radius 13X of the male screw portion 13. As a result, the insertion hole 52 and the external thread portion 13 of the linear motion rod 10 do not need to interfere with each other.

  Therefore, when the end 12c of the linear motion rod 10 is inserted into the insertion hole 52 of the washer 50, the washer-side contact portion 53 and the rod-side contact portion 23 come into contact with each other, and the screw shafts are aligned. Their relative rotation in the circumferential direction is restricted. That is, the washer-side contact portion 53 and the rod-side contact portion 23 act as the auxiliary relative rotation prevention mechanism B.

  Further, as the first relative rotation preventing mechanism A, a first receiving portion side unevenness 64 that engages with the piston side unevenness 104 is formed in the first receiving portion 60 of the washer 50. The 1st receiving part side unevenness | corrugation 64 becomes the saw blade shape provided in multiple numbers by the circumferential direction continuously. The direction in which each of the first receiving portion side irregularities 64 extends, that is, the direction in which the ridge line extends, is along the radial direction of the washer 50. As a result, the first receiving portion side unevenness 64 extends radially from the center of the through hole 52 of the washer 50.

  Further, the first receiving portion 60 is formed with a washer-side tapered surface inclined in the radial direction. The washer-side taper surface is inclined so that the center side approaches the stepped portion 20 side of the linear motion rod 10 (see FIG. 1), resulting in a concave conical shape. The first receiving portion side irregularities 64 described above are formed on the washer side tapered surface.

  As shown in FIGS. 3C and 3D, the insertion hole 100 a of the piston member 100 is formed with a female thread portion 106 a for screwing with the linear motion rod 10. Further, the piston member 100 is formed with a seat portion 102 that faces the first receiving portion 60 of the washer 50. Both the seat portion 102 and the first receiving portion 60 on the washer 50 side are annular surface regions, and abut against each other to play a role of transmitting a fastening force (axial force) to the step portion 20. That is, most of the axial force in this fastening structure is transmitted to the step portion 20 via the washer 50.

  As shown in FIG. 3, as the first relative rotation preventing mechanism A, the female screw side unevenness 104 is formed in the seat portion 102 of the piston member 100. The female screw side unevenness 104 has a saw blade shape that is continuously provided in the circumferential direction. The direction in which each of the female screw side irregularities 104 extends, that is, the direction in which the ridge line extends is the radial direction of the piston member 100. As a result, the female screw side unevenness 104 extends radially from the axis.

  Further, the seat portion 102 is formed with a female thread side tapered surface inclined in the radial direction. Since the female thread side taper surface is inclined so that the center side approaches the washer 50 side, as a result, a convex conical shape is formed on the stepped portion 20 side of the linear motion rod 10. The female screw side unevenness 104 described above is formed on the female screw side tapered surface.

  As described above, as the first relative rotation preventing mechanism A, since the female screw side unevenness 104 and the first receiving portion side unevenness 64 are formed in a saw blade shape that is continuous in the circumferential direction, a so-called ratchet mechanism or one-way clutch mechanism is provided. Works. As a result, during the fastening operation of the piston member 100, the relative movement of the female screw side unevenness 104 and the first receiving portion side unevenness 64 of the washer 50 is allowed to realize smooth relative rotation. On the other hand, during the loosening operation of the piston member 100, the relative movement of the female screw side unevenness 104 and the first receiving portion side unevenness 64 of the washer 50 is completely restricted. As a result, workability at the time of fastening and subsequent locking can be rationally achieved.

  Further, as the first relative rotation preventing mechanism A, the seat portion 102 and the first receiving portion 60 are formed with a piston-side tapered surface and a washer-side tapered surface, so that the contact area between both can be increased. Further, the fastening force in the axial direction by this fastening structure also acts in the radial direction by the tapered surface. By pressing the taper surfaces of each other in the radial direction, centering can be carried out by self-excitation. As a result, the concentricity between the piston member 100 and the washer 50 is increased, and the engagement accuracy between the female screw side unevenness 104 and the first receiving portion side unevenness 64 can be increased. It is also preferable to slightly increase the inclination of the convex female thread side taper surface and slightly decrease the inclination angle of the concave washer side taper surface so as to provide a small difference in angle. If it does in this way, a mutual taper surface can be made to contact | abut little by little toward the radial direction outer side from the center with the increase in clamping pressure.

  Further, the auxiliary relative rotation prevention mechanism B avoids the shapes of the washer-side contact portion 53 and the rod-side contact portion 23 from being concentric circles with respect to the screw shaft center. In other words, the shapes of the washer-side contact portion 53 and the rod-side contact portion 23 vary along the circumferential direction in the distance from the screw axis. Due to this non-circular shape, once the washer-side contact portion 53 and the rod-side contact portion 23 are in contact with each other, further relative rotation in the circumferential direction is restricted as long as the axes are aligned. In particular, the washer side abutting portion 53 and the rod side abutting portion 23 are not formed over the entire circumference of the linear motion rod 10, but are formed partially in the circumferential direction. These shape processing of the rod 10 can be, for example, simple chamfering processing or press processing.

  As shown in FIG. 4, when the washer 50 is inserted into the linear motion rod 10 and the piston member 100 is further tightened, the linear motion rod 10 and the washer 50 are first engaged in the circumferential direction by the auxiliary relative rotation prevention mechanism B. Further, when the piston member 100 is further tightened, in the first relative rotation prevention mechanism A, the female screw side tapered surface of the seat portion 102 enters the recess of the washer side tapered surface of the washer 50, and the female screw side unevenness 104 and the first receiving portion are formed. The side unevenness 64 is engaged and the state shown in FIG. 1 is obtained. As shown in FIG. 5 (A), both sawtooth shapes in the first relative rotation preventing mechanism A are such that when the piston member 100 tries to rotate in the fastening direction Y, the inclined surfaces 104Y and 64Y contact each other. The relative slide is allowed while the distance between the two is reduced in the axial direction. On the other hand, when the piston member 100 tries to rotate in the loosening direction X, the mutually perpendicular surfaces (surfaces with a strong inclination) 104X and 64X come into contact with each other to prevent the relative movement between them. In particular, the first relative rotation preventing mechanism A is engaged with the female screw side unevenness 104 and the first receiving portion side unevenness 64 as the distance between the female screw side seat portion 102 and the first receiving portion 60 decreases by tightening the piston member 100. It becomes stronger and the engagement strength on the loosening direction X side is increased. Here, the inclination angle of the female thread side taper surface and the inclination angle of the washer side taper surface are made different from each other. In particular, the inclination angle from the axis of the washer side taper surface is set to the inclination angle from the axis of the female screw side taper surface. By setting the width narrower than that, it is possible to tighten without play regardless of the pitch of the sawtooth formed on each tapered surface.

  As described above, according to the piston fastening structure of the first embodiment, the first relative rotation between the female thread side seat portion 102 of the piston member 100 and the first receiving portion 60 of the washer 50 is achieved by interposing the washer 50. The prevention mechanism A is configured, while the auxiliary relative rotation prevention mechanism B is configured between the insertion hole 52 of the washer 50 and the rod side cooperation region 17 of the linear motion rod 10. As a result, when the piston member 100 or the linear motion rod 10 tries to relatively rotate in the loosening direction, both the linear motion rod 10 and the linear motion rod 10 are caused by the circumferential engagement action of both the first relative rotation prevention mechanism A and the auxiliary relative rotation prevention mechanism B. The relative rotation of the piston member 100 is restricted, and reverse rotation, that is, loosening is prevented. Therefore, even if vibration etc. arise, the fastening state which does not loosen at all can be obtained. On the other hand, when the linear motion rod 10 and the piston member 100 are relatively rotated in the tightening direction, the one-way clutch structure of the first relative rotation prevention mechanism A allows the relative rotation of the washer 50 and the piston member 100. It is possible to do freely.

  In the first embodiment, as the first relative rotation preventing mechanism A, the case where the female screw side unevenness 104 and the first receiving portion side unevenness 64 are saw-tooth shaped is illustrated, but the present invention is not limited to this. For example, as shown in FIG. 5B, the unevenness of each other can be formed in a mountain shape (both are inclined surfaces). In this way, when the piston member 100 rotates in the loosening direction X, the inclined surfaces 104X and 64X tend to move relative to each other, and the female screw side unevenness 104 and the first receiving portion side unevenness are along this inclined surface. 64 tries to leave. If the moving distance (the angle α to be separated) is set larger than the lead angle of the piston member 100, the female screw side unevenness 104 and the first receiving portion side unevenness 64 may be further separated even if the piston member 100 tries to loosen. You will not be able to relax. 5B illustrates the isosceles triangle asperity in cross section. However, as shown in FIG. 5C, the slopes of the inclined surfaces 104Y and 64Y that are in contact with each other at the time of fastening rotation are smaller than those at the time of loose rotation. It is also preferable to make the inclination angles of the inclined surfaces 104X and 64X in contact with each other gentle. In this manner, the circumferential distance P between the inclined surfaces 104Y and 64Y that must be overcome during the fastening rotation can be shortened, so that the backlash (gap) after fastening can be reduced.

  Further, as an application of FIGS. 5A to 5C, as shown in FIG. 5D, corrugated irregularities with curved ridges and valleys are also preferable, and smooth operability can be obtained at the time of fastening. it can. Furthermore, in the first embodiment, the unevenness extending in the radial direction is exemplified, but it is also preferable to form a spiral (spiral) groove or mountain (unevenness) as shown in FIG. In addition, as shown in FIG. 6B, even a groove or mountain (unevenness) extending linearly can be inclined so that the circumferential phase changes with respect to the radial direction of the screw. Moreover, as shown in FIG. 6C, it is also preferable to adopt a so-called embossed shape in which a plurality of fine irregularities are formed both in the circumferential direction and the radial direction (planar shape) of the screw.

  Furthermore, unlike the first embodiment, the concave and convex shapes of the female screw side irregularities 104 and the first receiving portion side irregularities 64 do not necessarily need to be matched (similar). For example, different shapes from the various shapes in FIGS. 5 and 6 can be selected and combined with each other.

  In the first embodiment, the case where the female thread side tapered surface is convex and the washer side tapered surface is concave is illustrated, but the present invention is not limited to this, for example, the female thread side tapered surface is concave and washer. The side taper surface can be convex. On the other hand, both of them can be non-tapered surfaces perpendicular to the screw axis. Further, for example, if the elastic deformation of the washer 50 is effectively used, it is not necessary to match the inclination angles of the two tapered surfaces. Of course, only one of the piston member 100 or the washer 50 may be formed with a tapered surface. Furthermore, by making both the tapered surfaces convex or concave, the elastic deformation of the washer can be utilized to bring them into close contact. Further, in order to obtain the elasticity of the washer 50, the basic shape of the washer 50 is preferably a so-called spring washer shape or a disc spring shape in which a spiral shape is used.

  Moreover, although the linearly acting rod 10 of this first embodiment illustrated the case where a groove | channel (constriction) was provided in the boundary of the rod side cooperation area | region 35 and the external thread part 13 in detail in the middle of the edge part 12c, this invention is shown. It is not limited to this. A structure in which the rod-side cooperation region 35 and the male screw portion 13 are continuous without a groove is also preferable, and the strength of the linear rod 10 can be increased. Moreover, although the case where the step part 20 was formed in the boundary of the main-body part 12a and the edge part 12c was shown, this invention is not limited to this, It is made to make the main-body part 12a and the edge part 12c continue with the same diameter. Good.

  Furthermore, as an application of the auxiliary relative rotation prevention mechanism B of the first embodiment, as shown in FIG. 7A, as the rod-side cooperation region 17 of the linear motion rod 10, a plurality of locations around the end portion 12c (here, You may form rod side contact part 23A in 2 places. As shown in FIG. 7B, a projection 23B that protrudes radially outward from the periphery of the end 12c may be formed as the rod-side cooperation region 17 of the linear motion rod 10. As shown in FIG. 7C, the end 12c may be a polygonal section 23C (here, a hexagon) as the rod-side cooperation region 17 of the linear motion rod 10. Further, as shown in FIG. 7D, the end 12c may be formed into an elliptical cross section 23D as the rod-side cooperation region 17 of the linear motion rod 10. All of them have a “non-circular cross section” shape. At this time, although not particularly shown, it is preferable that the insertion hole 52 of the washer 50 has a similar shape corresponding to these, but it is necessary to make both the shapes similar if they can be engaged in the circumferential direction. Absent.

  In the case of this structure, as shown in FIG. 8, a convex positioning taper surface 11 is formed on the linear motion rod 10, and a concave positioning taper surface 51 is formed on the washer 50. It is preferable to contact. As a result, by tightening the washer 50 with the piston member 100 so that the positioning tapered surfaces 11 and 51 are pressed against each other, the axes of the washer 50 and the linear rod 10 can be made to coincide with each other with high accuracy. Become. Note that oil leakage may be suppressed by interposing the inner seal ring 12 between the positioning taper surfaces 11 and 51.

  Although not shown here, it is also possible to make the linking member (washer) 50 and the piston member 100 have substantially the same radius size, and both can function as a piston. In the following, it is first described that in the second embodiment and thereafter, the cooperating member (washer) can also serve as the piston.

  Next, with reference to FIG.9 and FIG.10, the fastening structure of the piston which concerns on 2nd embodiment is demonstrated. In addition, description is abbreviate | omitted about the structure or member similar or similar to 1st embodiment.

  As shown in FIG. 10A, the rod side cooperation region 17 is formed in the linear motion rod 10 so as to overlap the male screw portion 13. The rod-side cooperation region 17 is such that, when viewed from the axial direction, a part of a circular arc having a right circular cross section formed along the apex of the thread is omitted (or cut) along the chord. The shape of the string is the rod side contact portion 23. That is, by omitting a part of the screw thread so as to be continuous in the axial direction, a virtual plane P that is perpendicular to the radial direction and directed outward in the radial direction is formed, and this virtual plane P is the rod-side contact portion 23. It becomes. Accordingly, the minimum radius 17Y of the rod side cooperation region 17 is set to be smaller than the maximum radius 13X of the male screw portion 13.

  Furthermore, in this embodiment, the thread valley bottom 13a remains around the rod side contact portion 23 in the axial direction. As a result, the function of screwing with the piston member 100 remains. Specifically, in the rod side contact portion 23, it is preferable to omit the upper limit of two-thirds of the thread height, and more preferably, omit the upper limit of one-half of the thread height. To do. Therefore, the minimum radius (minimum distance) 17Y of the rod side cooperation region 17 is larger than the minimum radius (valley bottom radius) 13Y from the axis of the male screw portion 13. In the present embodiment, the rod-side contact portions 23 are formed at three locations that have a phase difference of 23 degrees in the circumferential direction.

  As shown in FIG. 10B, the insertion hole 52 through which the piston rod of the washer 50 can be inserted is a non-circular shape when viewed from the axial direction. The insertion hole 52 has a partial arc shape concentric with the axis of the screw and has a shape in which the remaining portion is cut off linearly like a string. 53. In the present embodiment, the washer-side contact portions 53 are formed in three places that have a phase difference of 120 degrees in the circumferential direction. The washer side abutting portion 53 abuts on the rod side abutting portion 23 of the rod side cooperation region 17 so as to engage with each other in the circumferential direction to constitute the auxiliary relative rotation preventing mechanism B.

  As described above, according to the piston fastening structure of the second embodiment, as shown in FIG. 9, rod-side cooperation formed in an overlapping manner on the insertion hole 52 of the washer 50 and the male thread portion 13 of the linear rod 10. An auxiliary relative rotation prevention mechanism B can be configured between the regions 17. Accordingly, the engagement position with the washer 50 can be freely changed within the range in which the rod-side cooperation region 17 exists. Therefore, the fixing position of the piston 10 can be adjusted only by changing the axial dimension of the washer 50. . Note that a sleeve may be interposed between the washer 50 and the step portion 20 of the linear rod 10, and in that case, the fixed value position of the piston 10 can be adjusted only by changing the axial dimension of the sleeve. Furthermore, here, since the bottom of the thread is left as much as possible in the rod side contact portion 23 of the rod side cooperation region 17, a decrease in the fastening force with the piston member 100 hardly occurs. Yes.

  In addition, although the linear motion rod 10 of this 2nd embodiment illustrated the case where the rod side cooperation area | region 17 was not provided in the main-body part 12a, making the cross-sectional shape of the main-body part 12a substantially correspond with the rod side cooperation area | region 17. Thus, it is possible to extend the rod side cooperation region 17 to the main body portion 12a. Of course, the main body 12a itself can be eliminated.

  FIG. 11 shows another modification of the second embodiment. As shown in FIG. 11 (A), in the rod side cooperation region 17 formed to overlap with the male screw portion 13, when viewed from the axial direction, the rod side contact portion 23 in which the top of the thread is omitted in a concave shape is formed. It is formed. More specifically, the rod-side abutting portion 23 is configured such that the top of the thread is recessed in a V shape, and is formed at twelve locations in the circumferential direction at equal intervals. A minimum distance (bottom portion of the dent) 17Y from the axis of the rod side contact portion 23 is set to be smaller than the maximum radius 13X of the male screw portion 13 and larger than the minimum radius (valley bottom radius) 30bY of the male screw portion 13. The

  Therefore, as shown in FIG. 11 (B), the insertion hole 52 of the washer 50 assembled to the linear motion rod 10 also has a washer side that is convex inward in the radial direction so as to be similar to the rod side cooperation region 17. The contact parts 53 are formed at twelve places in the circumferential direction at equal intervals. As a result, the washer 50 and the linear rod 10 can be engaged in the circumferential direction.

  In the second embodiment, the minimum distance 17Y from the axis of the rod-side contact portion 23 in the rod-side cooperation region 17 formed in the male screw portion 13 is smaller than the minimum radius (valley bottom radius) 30bY of the male screw portion 13. Although the case where it is set large is illustrated, the present invention is not limited to this. For example, as shown in FIG. 12A, an axial groove deeper than the bottom of the thread can be formed in the male screw portion 13, and this can be used as the rod-side contact portion 23. As a result, the minimum distance 17Y from the axis of the rod-side contact portion 23 is smaller than the minimum radius (valley bottom radius) of the male screw portion 13. In this case, the result is that the thread of the male thread portion 13 is partially omitted including the valley bottom. A washer-side contact portion 53 that protrudes inward in the radial direction is also formed in the insertion hole 52 of the washer 50, and the minimum distance from the axial center is the minimum radius (valley bottom radius, that is, the valley diameter) of the male screw portion 13. Make it smaller. As a result, it is possible to increase the circumferential engagement dimension between the washer-side contact portion 53 and the rod-side contact portion 23.

  In the first and second embodiments, the case where the washer 50 and the piston member 100 are formed with inclined surfaces (tapered surfaces) and brought into contact with each other is illustrated, but the present invention is not limited to this. As shown in FIG. 12B, a cylindrical surface is formed on both the washer 50 and the piston member 100, a first receiving portion side unevenness 64 is formed on the cylindrical surface of the washer 50, and a female screw is formed on the cylindrical surface of the piston member 100. By forming the side irregularities 104, they may be engaged with each other in the circumferential direction.

  Further, in the first and second embodiments, the case where the linear motion rod 10 has the stepped portion 20 is illustrated, but the present invention is not limited to this. For example, as an application of the first embodiment, as shown in FIG. 13, it is possible to fasten the cooperative member (washer) 50 so as to be sandwiched between the pair of piston members 100, 100 from both sides. At this time, a pair of receiving portions 60 serving as the first relative rotation preventing mechanism A is formed on both sides of the linkage member 50, and the receiving portions 60 and 60 are engaged with the seat portion 102 of the piston member 100. In this way, the piston members 100, 100 arranged on both sides are prevented from rotating relative to the linear motion rod 10 in the loosening direction due to the presence of the receiving portions 60, 60 formed on the cooperation member 50. The

  Furthermore, as an application of the second embodiment, it is possible to fasten a cooperative member (washer) 50 as shown in FIG. 14 so as to be sandwiched between the pair of piston members 100, 100 from both sides. In the linear motion rod 10, the stepped portion 20 is omitted, and a male screw portion 13 is formed therein, and a rod side cooperation region 17 is formed so as to overlap with the male screw portion 13. A pair of receiving portions 60 serving as the first relative rotation preventing mechanism A is formed on both sides of the linkage member 50, and the receiving portions 60 and 60 are engaged with the seat portion 102 of the piston member 100. In this way, the piston members 100, 100 arranged on both sides are prevented from rotating relative to the linear motion rod 10 in the loosening direction due to the presence of the receiving portions 60, 60 formed on the cooperation member 50. The

  13 and 14 realizes that the pair of piston members 100, 100 are fixed at an arbitrary position on the linear motion rod, but only one of the pair of piston members is substantially used. The piston 100 may function, and the other may function as a female screw body. Further, the cooperation member 50 can also serve as a part of the piston. Specifically, as shown in FIG. 15, a piston member 100A that also serves as a female screw body is fastened from one side to a cooperative member (washer) 50 having receiving portions 60, 60 on both sides, and a female screw body is provided from the other side. If 100B is fastened, the three members of the piston member 100A, the linkage member 50, and the female screw body 100B can be fixed at an arbitrary place.

  Further, as in the structure of FIG. 16 which is a modified example of the piston fastening structure of FIG. 15, an arm 58 that wraps around to the polygonal circumferential surface of the female screw body 100 </ b> B or the plane opposite to the seat portion 102 in the washer 50. It is also preferable to form the relative rotation prevention mechanism A by forming the arm 58 and the female screw body 100B in the circumferential direction.

  Next, the piston fastening structure of the third embodiment will be described with reference to FIGS. 17 and 18. The third embodiment is an application of the piston fastening structure shown in FIG. 11 of the second embodiment, and the description of the same or similar members is omitted. This piston fastening structure is characterized in that the function of the washer (cooperating member) 50 is provided integrally with the piston member 100 so that the independent washer (cooperating member) 50 can be omitted.

  As shown in FIG. 18, the piston member 100 has a piston-side cooperation region 106 b that has a non-circular cross section when viewed from the axial direction in the insertion hole 100 a that has a female screw portion 106 a that is screwed with the male screw portion 13. The piston-side cooperation region 106b is provided on the opposite side of the seat portion 102 of the piston member 100 so as to protrude in a ring shape in the axial direction, but may be provided on the seat portion 102 side and overlaps with the female screw portion 106a. You may form as follows.

  In the piston-side cooperation region 106b, female screw-side contact portions 108 that protrude inward in the radial direction are formed on the inner peripheral surface of the insertion hole 100a at equal intervals in the circumferential direction. As a result, the female screw side contact portion 108 can be engaged in the circumferential direction with the rod side contact portion 23 formed to be recessed in the male screw portion 13 of the linear motion rod 10. As already described, the female thread side abutting portion 108 protrudes in the axial direction on the opposite side of the seat portion 102 of the piston member 100 and is thinly provided so that it can be elastically deformed radially outward. By causing the linearly acting rod 10 and the piston member 100 to rotate relative to each other with a desired force, the piston-side contact portion 108 is elastically deformed outward, and the circumferential engagement with the rod-side contact portion 23 is released. Can do.

  Therefore, as shown in FIG. 17, a positioning sleeve 18 is disposed between the step portion 20 of the linear rod 10 and the piston member 100, and the piston member 100 is moved to the linear rod 10 with a desired force. By urging in the tightening direction, the rod side contact portion 23 and the internal thread contact portion 108 can be relatively rotated while being repeatedly engaged and released, so that the piston member 100 can be fixed at a position in the middle of the external thread portion. More desirably, as a so-called ratchet mechanism in which at least one of the rod-side contact portion 23 and the female screw-side contact portion 108 has a saw blade shape, rotation in the tightening direction is allowed and rotation in the loosening direction is restricted. Make it work.

  In 1st thru | or 3rd embodiment, although the case where the rod side contact part 23 of the rod side cooperation area | region 17 extended linearly in an axial direction was mainly illustrated, this invention is not limited to this. For example, as shown in FIGS. 19A and 19B, it is also preferable that the rod-side contact portion 23 is formed to be spirally inclined with respect to the axial direction. At this time, the spiral direction of the rod side contact portion 23 is the same as the spiral direction of the thread of the male screw portion, and the lead is desirably set larger than the lead of the male screw portion. As a result, when the cooperating member (for example, a washer) rotates with the female screw body (for example, a piston) when the female screw body rotates in the loosening direction, the cooperating member is pressed against the female screw body by the difference in the lead, so that the first relative rotation prevention The mechanism A can be more firmly engaged to prevent loosening.

  Moreover, although the case where the piston ring 90 was fitted by the groove | channel formed in the surrounding surface of the piston member 100 was illustrated in 1st thru | or 3rd embodiment, this invention is not limited to this. For example, as shown in FIG. 20A, it is preferable to form an annular outer seal fitting portion 210 that continues from the middle of the outer peripheral surface of the piston member 100 to the end surface on the washer 50 side.

  The outer seal fitting portion 210 forms a small-diameter surface 201 that continues to the end surface on the washer 50 side on the peripheral surface, and the piston ring 90 is inserted therein. The small diameter surface 201 is smaller in diameter than the outer peripheral surface (seal portion 105a) of the piston member 100, and the piston ring 90 is positioned in the axial direction by the step 205 formed on the seal portion 105a and the small diameter surface 201. The axial dimension of the piston ring 90 is set to be slightly larger than the axial dimension of the small diameter surface 201, and the piston ring 90 slightly protrudes from the piston member 100 toward the washer 50. The washer 50 is set to have a diameter larger than that of the small diameter surface 201. Therefore, when the washer 50 and the piston member 100 are fastened, the end face of the washer 50 comes into contact with the piston ring 90 and the piston ring 90 is fixed. That is, the piston ring 90 is sandwiched between the piston member 100 and the washer 50.

  As a result, the piston ring 90 can be easily assembled as compared with the conventional case where the sealing material is fitted and installed while being elastically deformed. Accordingly, since it is not necessary to consider the elastic deformation of the piston ring 90, it is possible to select a material having high rigidity and high wear resistance. In addition, as shown to FIG. 20 (B), the internal peripheral surface of piston ring 90 can also be made into taper surface 90a, 90b, and can also improve sealing performance. In this case, the outer seal fitting portions 210 and 56 are formed on the outer peripheral surface of the piston member 100 and / or the washer 50, and the tapered surfaces 203 facing the tapers 90a and 90b of the piston ring 90 are formed on the respective peripheral surfaces. 55a may be formed. Using the clamping force between the piston member 100 and the washer 50, the tapered surfaces 90a and 90b of the piston ring 90 and the tapered surfaces 203 and 55a of the piston member 100 and / or the washer 50 can be closely contacted and positioned in the axial direction. .

  Furthermore, in the modification shown in FIG. 8 of the first embodiment, the inner seal ring 12 is interposed between the positioning tapered surface 11 of the shaft portion 12 of the linear rod 10 and the tapered surface 51 of the piston 50. Although illustrated, this invention is not limited to this. For example, as shown in FIG. 21, the inner seal ring 12 can be installed on the main body 12 a of the linear motion rod 10, and the positioning tapered surface 11 can be formed on the outer periphery of the inner seal ring 12. The inner seal ring 12 is positioned in the axial direction by contacting the stepped portion 21. On the other hand, in the insertion hole 100a of the linkage member 50, an annular inner seal accommodation hole 250 that continues from the middle to the end face is formed.

  The inner seal accommodation hole 250 has a positioning taper surface 51 formed on the inner periphery thereof, and the positioning taper surface 51 and the positioning taper surface 11 of the inner seal ring 12 are brought into close contact with each other so that the axial direction of the cooperation member 50 is increased. The oil leakage can be suppressed at the same time as positioning. At this time, if the fastening force of the piston member 100 is adjusted, the degree of close contact between the positioning taper surfaces 11 and 51 can be appropriately changed.

  Further, in the first to third embodiments, the piston side taper surface is formed on the seat portion 102 of the piston member 100 and the self-excited centering with the washer 50 is exemplified. It is not limited to. For example, as in the modification of the third embodiment shown in FIG. 22A, an annular tapered surface 250 is formed in the insertion hole 100a or the end surface 102 of the piston member 10, and the positioning taper surface of the linear motion rod 10 is formed. It is also preferable that the piston member 100 is directly centered between the piston member 100 and the linear motion rod 10 in contact with the piston 11.

  Furthermore, in said 1st thru | or 3rd embodiment, the cooperation member (washer) 50 was comprised as a separate member from the linear motion rod 10, and illustrated the structure which prevents loosening of the piston member 100 using this cooperation member 50. However, the present invention is not limited to this. For example, as in a modification of the first embodiment shown in FIG. 22B, the linear motion rod 10 may be provided with a function equivalent to that of the cooperation member (washer) 50 in an integrated manner. That is, the linear motion rod 10 integrally has the extension portion 50X, and the first receiving portion 60 facing the seat portion 102 of the piston member 100 may be formed in the extension portion 50X. As a result, the first relative rotation prevention mechanism A is configured between the expansion portion 50 </ b> X of the linear motion rod 10 and the piston member 100. In the first relative rotation preventing mechanism A, when at least the piston member 100 tries to rotate in the loosening direction with respect to the linearly acting rod 10 to be screwed, the first receiving portion 60 and the seat portion 102 are engaged with each other. Prevent relative rotation.

  In addition, in the said embodiment, although the case where the washer side contact part of a cooperation member (washer) becomes concave shape in the circumferential direction inside mainly is illustrated, you may be convex in the circumferential direction inner side.

  FIG. 23A is a plan view of the piston fastening structure 1 according to the fourth embodiment, and FIG. 23B is a front view of the fastening structure 1. FIG. 24 is a cross-sectional view taken along line AA in FIG. As shown in these drawings, the fastening structure 1 fastens the piston member 100 to the linear motion rod 10 and fixes them together. The linear motion rod 10 and the first female screw portion 106a formed on the piston member 100 are used. And a fixing female screw body 30 and a relative rotation preventing mechanism 40.

  As shown in FIG. 24, the linear motion rod 10 has a substantially rod-shaped (substantially cylindrical) main body portion 12a having a large diameter from the center toward the end portion, and a columnar positioning portion having a smaller diameter than the main body portion 12a. 12b and a cylindrical end portion 12c having a smaller diameter than the positioning portion 12b. Therefore, the first shaft side step portion 11a is formed at the boundary between the main body portion 12a and the positioning end portion 12b, and the second shaft side step portion 11b is formed at the boundary between the positioning end portion 12b and the end portion 12c. A male screw portion 13 in which a male screw spiral groove is formed is provided on the outer peripheral surface of the end portion 12c. In the present embodiment, the male screw portion 13 includes a first male screw spiral groove 14 that is a right screw, and a left screw. The two types of male screw spiral grooves 15 of the second male screw spiral groove 15 are overlapped on the same region.

  In FIG. 25, the external thread part 13 of the linear motion rod 10 is enlarged and shown. The male screw portion 13 has a substantially crescent-shaped thread 13a continuous in a plane direction perpendicular to the axis (screw shaft) C, on one side (left side in the figure) and the other side (right side in the figure). By forming the screw thread 13a in this way, two types of spiral grooves, a spiral groove turning clockwise and a spiral groove turning counterclockwise, are formed between the screw threads 13a. I can do it.

  In the present embodiment, two types of male screw spiral grooves, that is, the first male screw spiral groove 14 and the second male screw spiral groove 15 are formed in the male screw portion 13 in this manner. Therefore, the male thread portion 13 can be screwed with any of the right and left thread female thread bodies. For the details of the male screw portion 13 in which two types of male screw spiral grooves are formed, refer to Japanese Patent No. 4666313 related to the inventor of the present application.

  Returning to FIG. 24, the piston member 100 is a cylindrical member, and has an annular outer peripheral surface 105 facing the inner peripheral surface of the tube 4, a pair of end surfaces 101 facing in the axial direction, and coaxial with the outer peripheral surface. It has the insertion hole 100a formed in a shape. The outer peripheral surface 105 approaches the inner peripheral surface of the tube 4 and serves as a seal portion 105a that restricts the movement of the working fluid. At least one of the end surfaces 101 (here, both) serves as a pressure receiving surface 101a that receives the pressure of the working fluid. The linear motion rod 10 is inserted into the insertion hole 100a.

Specifically, the insertion hole 100a has a first insertion hole 100a1 having a large diameter and a second insertion hole 100a2 having a small diameter coaxially. The first insertion hole 100a1 is located on the center side of the linear motion rod 10, and has a size slightly larger than the diameter of the main body portion 12a or the positioning portion 12b of the linear motion rod 10. The second insertion hole 100a2 is located on the shaft end side of the linear motion rod 10, and a first female thread portion 106a is formed on the inner peripheral surface. As a result, a hole-side stepped portion 100b is formed at the boundary between the first insertion hole 100a1 and the second insertion hole 100a2. An annular seal ring 90 that functions as a piston ring is disposed on the outer peripheral surface of the piston member 100. The seal ring 90 is fitted into a groove formed on the outer peripheral surface of the piston member 100. As the material of the seal ring 90, for example, a synthetic resin such as a thermoplastic resin or a thermosetting resin is used. Of course, the material of the seal ring 90 is not limited to synthetic resin, and is not particularly limited as long as it can maintain hermeticity.

  A cylindrical stopper 80 that engages with the first shaft side step portion 11a is disposed on the outer periphery of the positioning portion 12b of the linear rod 10. The stopper 80 is configured to be slightly longer than the axial dimension of the positioning portion 12b, and protrudes toward the end side from the second shaft side step portion 11b. The outer diameter of the stopper 80 substantially matches the inner diameter of the first insertion hole 100 a 1 of the piston member 100.

  Accordingly, when the end portion of the linear rod 10 on which the stopper 80 is installed is inserted into the first insertion hole 100a1 of the piston member 100, the outer peripheral surface of the stopper 80 is in contact with the inner peripheral surface of the first insertion hole 100a1 of the piston member 100. Further, the end face of the stopper 80 comes into contact with the hole-side step portion 100b. That is, both ends of the stopper 80 abut on the first shaft side step portion 11a and the hole side step portion 100b, whereby the linear motion rod 10 and the piston member 100 are positioned in the axial direction. An inner seal 42 made of synthetic resin is disposed between the inner peripheral surface of the stopper 80 and the outer peripheral surface of the positioning portion 12b. The inner seal 42 is embedded in an annular groove formed on the outer peripheral surface of the positioning portion 12b. Here, the inner seal 42 is set to be made of a synthetic resin, but is not necessarily made of a synthetic resin and is not particularly limited as long as it can maintain hermeticity.

  The first female screw portion 106 a of the piston member 100 is screwed into the male screw portion 13 of the linear motion rod 10. Accordingly, the piston member 100 is fastened to the linear motion rod 10 by itself as an internal thread. Furthermore, a fixing female screw body 30 is screwed into the male screw portion 13 from the outside of the piston member 100. Accordingly, the piston member 100 is fixed so as to be sandwiched between the stopper 80 and the fixing female screw body 30.

  A first female thread spiral groove which is a right-hand thread is formed in the first female thread portion 106 a of the piston member 100. That is, the first female screw portion 106 a is screwed with the first male screw spiral groove 14 in the male screw portion 13 of the linear motion rod 10.

  The external thread body 30 for fixing is not particularly limited in outer shape and the like, but has a so-called hexagonal nut shape in the present embodiment. Therefore, the fixing female screw body 30 is configured in a substantially hexagonal column shape having six plane portions 31a and corner portions 31b (see FIG. 23A) on the outer peripheral surface 31, and has a screw hole 32 penetrating in the axial direction. I have. A second female screw spiral groove that is a left-hand thread is formed in the second female screw portion 33 that is the inner peripheral surface of the screw hole 32. That is, the fixing female screw body 30 is screwed into the second male screw spiral groove 15 in the male screw portion 13 of the linear motion rod 10. The end surface 38 is provided with a relative rotation prevention mechanism 40 described later.

  FIGS. 26A to 26D are views showing a relative screwing operation of the piston member 100 and the fixing female screw body 30 in a state where the relative rotation preventing mechanism is ignored. Since the piston member 100 and the fixing female threaded body 30 are in a reverse screw relationship with each other, as shown in FIGS. If they are (or both are fixed and the linear rod 10 is rotated), they will move in opposite directions along the axis C.

  Specifically, as shown in FIG. 5A, the rotation direction of the piston member 100 and the fixing female screw body 30 with respect to the linear motion rod 10 is counterclockwise when viewed from the fixing female screw body 30 side (the upper side in the figure). In this case, the piston member 100 and the fixing female screw body 30 move in the direction of approaching each other along the direction of the axis C. However, when the piston member 100 and the fixing female screw body 30 are already in close contact with each other, the piston member 100 and the fixing female screw body 30 are naturally restricted from being simultaneously rotated.

  Further, as shown in FIG. 5B, when the rotation direction of the piston member 100 and the fixing female screw body 30 is clockwise when viewed from the fixing female screw body 30 side (the upper side in the figure), the piston member 100 and the female screw body 30 for fixation move in the direction away from each other along the direction of the axis C. However, when the piston member 100 is already in contact with the stopper 80 (see FIG. 24), the piston member 100 cannot move any further, and therefore the piston member 100 and the fixing female screw body 30 are automatically rotated simultaneously. Be regulated.

  Of course, as shown in FIG. 3C, when only the fixing female screw body 30 is rotated clockwise, the fixing female screw body 30 can be loosened. Further, as shown in FIG. 4D, when only the fixing female screw body 30 is rotated clockwise and at the same time the piston member 100 is rotated counterclockwise, both are loosened simultaneously.

  As can be understood from the above screwing operation, when the piston member 100 and the fixing female screw body 30 are sufficiently fastened to the linear motion rod 10, the piston member 100 and the fixing female screw body 30 rotate in the same direction. Is structurally impossible (see FIGS. 26A and 26B). In other words, the linear motion rod 10 cannot be rotated relative to the piston member 100 and the fixing female screw body 30. On the other hand, it can be understood that the fastening state is loosened when only the fixing female screw body 30 rotates or when the piston member 100 and the fixing female screw body 30 are rotated in opposite directions. That is, in this fastening structure, if the “relative rotation after fastening” of the piston member 100 and the fixing female screw body 30 is restricted, the piston member 100 and the fixing female screw body 30 can maintain a state in which they are not structurally detached. .

  Based on the above consideration, the relative rotation preventing structure 40 employed in the present embodiment will be described.

  Referring back to FIG. 24, the relative rotation preventing mechanism 40 includes a first engagement hole 191 that is a female screw hole formed in the piston member 100, a second engagement hole 181 that is formed in the female screw body 30 for fixation, The external male screw body 110 and the annular washer 150 are provided. The second engagement hole 181 is an insertion hole, and the first engagement hole 191 formed in the piston member 100 is a non-insertion hole. An engaging female thread portion is formed on the inner peripheral surface of the first engaging hole 191. The engaging male screw body 110 is screwed into the first engaging hole 191 through the second engaging hole 181. As a result, the engaging male screw body 110 is consistently inserted into the first engaging hole 191 and the second engaging hole 181, and the relative rotation of the piston member 100 and the fixing female screw body 30 is restricted. The female screw hole may be formed not on the first engagement hole 191 side but on the second engagement hole 181 side.

  As shown in FIG. 27, the engaging male screw body 110 is a so-called bolt, and has a head portion 120 and a shaft portion 130. A screw body side seat portion 122 is formed in a portion corresponding to a lower portion or a root of the head portion 120. The shaft portion 130 is formed with a cylindrical portion 130a and a screw portion 130b. Of course, the cylindrical portion 130a is not essential.

  A first receiving portion 160 is formed on one side of the washer 150 (the upper surface side in FIG. 27). This 1st receiving part 160 has opposed the screw body side seat part 122, and the 1st engagement mechanism A is comprised among both. In the first engagement mechanism A, when at least the screw body side seat portion 122 tries to rotate in the direction of loosening the engaged male screw body 110, the first receiving portion 160 and the screw body side seat portion 122 engage with each other. Thus, relative rotation between the first receiving portion 160 and the screw body side seat portion 122 with respect to the rotation direction is prevented.

  A second receiving portion 170 is formed on the other side of the washer 150 (the lower surface side in FIG. 27). The second receiving portion 170 faces the fixing female screw body 30.

  A member-side seat portion 182 that faces the second receiving portion 170 of the washer 150 is formed in the fixing female screw body 30. A second engagement mechanism B is configured between the member side seat portion 182 of the fixing female screw body 30 and the second receiving portion 170 of the washer 150. In this second engagement mechanism B, when at least the washer 150 tries to rotate in the loosening direction together with the engaging male screw body 110, the second receiving portion 170 and the member side seat portion 182 engage with each other, and the rotation direction Relative rotation between the second receiving portion 170 and the member side seat portion 182 is prevented.

  When the engagement male screw body 110 tries to rotate in the loosening direction by the action of the first engagement mechanism A and the second engagement mechanism B, the engagement male screw body 110 and the fixing female screw body 30 are interposed by the washer 150. Relative rotation is restricted. As a result, the engaging male screw body 110 is prevented from loosening.

  As shown in FIG. 28, as the first engagement mechanism A, the screw body side unevenness 124 is formed on the screw body side seat portion 122 of the engaging male screw body 110. The screw body side unevenness 124 has a saw blade shape that is continuously provided in the circumferential direction. The direction in which each of the threaded body side irregularities 124 extends, that is, the direction in which the ridge line extends, is the radial direction of the engaging male threaded body 110. As a result, the screw body side unevenness 124 extends radially from the axis.

  Further, the threaded body side seat portion 122 is formed with a threaded body side tapered surface 126 inclined in the radial direction. Since the screw body side tapered surface 126 is inclined so that the center side approaches the screw tip, as a result, a convex conical shape is formed on the screw tip side. More preferably, the aforementioned threaded body side unevenness 124 is formed on the threaded body side tapered surface 126.

  As shown in FIG. 29, as the first engagement mechanism A, the first receiving portion 160 of the washer 150 is formed with a first receiving portion-side unevenness 164 that engages with the screw body-side unevenness 124. The 1st receiving part side unevenness | corrugation 164 becomes the saw blade shape provided in multiple numbers by the circumferential direction. The direction in which each of the first receiving part side irregularities 164 extends, that is, the direction in which the ridge line extends, is along the radial direction of the engaging male screw body 110. As a result, the first receiving portion side unevenness 164 extends radially from the center of the through hole 152 of the washer 150.

  Further, preferably, the first receiving portion 160 is formed with a washer side tapered surface 166 inclined in the radial direction. The washer-side tapered surface 166 has a mortar shape that is inclined so that the center side approaches the screw tip, and as a result, has a concave conical shape on the screw tip side. On the washer side tapered surface 166, the first receiving portion side unevenness 164 described above is formed.

  As a result, when the engaging male screw body 110 is tightened, in the first engagement mechanism A, the screw body side tapered surface 126 of the screw body side seat portion 122 enters the recess of the washer side tapered surface 166 of the washer 150, and the screw body side The unevenness 124 and the first receiving portion side unevenness 164 are engaged. As shown in FIG. 30 (A), when the engaging male screw body 110 tries to rotate in the fastening direction Y, the inclined surfaces 124Y and 164Y come into contact with each other, and the distance between the two is determined in the axial direction. Allow relative sliding while releasing. On the other hand, when the engaging male screw body 110 attempts to rotate in the loosening direction X, the mutually perpendicular surfaces (surfaces with a strong inclination) 124X and 164X come into contact with each other to prevent relative movement between the two. In particular, the first engagement mechanism A engages the screw body side unevenness 124 and the first receiving portion side unevenness 164 as the distance between the screw body side seat portion 122 and the first receiving portion 160 decreases by tightening the engaging male screw body 110. And the engagement strength on the loosening direction X side is increased. Here, the inclination angle of the screw body side taper surface 126 and the inclination angle of the washer side taper surface 166 are made different from each other. In particular, the inclination angle from the axis of the washer side taper surface 166 is set to the axis of the screw body side taper surface 126. By setting it to be narrower than the inclination angle from, it is possible to tighten without rattling regardless of the pitch of the sawtooth formed on each tapered surface.

  Returning to FIG. 29, the outer wall 172 of the second receiving portion 170 of the washer 150 varies along the circumferential direction in the distance from the axial center of the screw. Specifically, the outer wall 172 has a circular shape that is eccentric with respect to the axial center of the screw (the center of the insertion hole 152).

  On the other hand, the member side seat portion 182 of the fixing female screw body 30 includes a fitting portion 184 for accommodating the second receiving portion 170 of the washer 150, and the inner wall of the fitting portion 184 is also made of a screw. It has a circular shape that is eccentric with respect to the shaft center. The amount of eccentricity is the same in the second receiving portion 170 and the fitting portion 184, and the diameter difference (margin gap) between the second receiving portion 170 and the fitting portion 184 is set smaller than the amount of eccentricity.

  Therefore, as shown in FIG. 27, when the second receiving portion 170 of the washer 150 is accommodated in the fitting portion 184 of the fixing female screw body 30, both are fitted together, and the screw shafts are aligned. As it is, relative rotation in the circumferential direction of both is restricted. That is, the second receiving part 170 and the fitting part 184 act as the second engagement mechanism B.

  As a result, according to the relative rotation preventing mechanism 40, the first engagement mechanism A is configured between the screw body side seat portion 122 and the first receiving portion 160 by interposing the washer 150. When the second engaging mechanism B is configured between the second receiving portion 170 and the engaging male screw body 110 is about to be loosened, the restricting action of both the first engaging mechanism A and the second engaging mechanism B is performed. The engaging male screw body 110 is engaged with the fixing female screw body 30 in the circumferential direction, and is prevented from rotating backward, that is, loosening. Therefore, even if vibration etc. arise, the fastening state which does not loosen at all can be obtained. As a result, the engaging male screw body 110 can reliably restrict the relative rotation of the piston member 100 and the fixing female screw body 30.

  Furthermore, here, as the first engagement mechanism A, the screw body side unevenness 124 and the first receiving portion side unevenness 164 have a saw blade shape that is continuous in the circumferential direction, and acts as a so-called ratchet mechanism or one-way clutch mechanism. . As a result, during the fastening operation, the screw body side unevenness 124 and the first receiving portion side unevenness 164 are allowed to move relative to each other to realize a smooth relative rotation, while during the loosening operation, the screw body side unevenness 124 and the first receiving portion. The relative movement of the side irregularities 164 is completely restricted. As a result, workability at the time of fastening and subsequent locking can be rationally achieved.

  Further, as the first engagement mechanism A, the threaded body side seat part 122 and the first receiving part 160 are formed with the threaded body side tapered surface 126 and the washer side tapered surface 166, so that the contact area between them can be increased. I can do it. Further, the fastening force in the axial direction of the engaging male screw body 110 also acts in the radial direction by the tapered surface. By pressing the taper surfaces of each other in the radial direction, centering can be carried out by self-excitation. As a result, the concentricity between the engaging male screw body 110 and the washer 150 is increased, and the engagement accuracy of the screw body side unevenness 124 and the first receiving portion side unevenness 164 can be increased. It is also preferable to slightly increase the inclination of the convex thread body side tapered surface 126 and to slightly decrease the inclination angle of the concave washer side tapered surface 166 to provide a small difference in angle. If it does in this way, a mutual taper surface can be made to contact | abut little by little toward the radial direction outer side from the center with the increase in clamping pressure.

  In the second engagement mechanism B, the outer wall of the second receiving portion 170 of the washer 150 and the inner wall of the fitting portion 184 of the fixing female screw body 30 are prevented from being concentric with respect to the axis of the screw. doing. In other words, the distance from the axial center of the screw of the inner wall of the fitting part 184 and the outer wall of the second receiving part 170 changes along the circumferential direction. With this shape, when the inner wall of the fitting portion 184 and the second receiving portion 170 are fitted together, relative rotation in the circumferential direction is restricted while keeping the axial centers thereof aligned. In particular, here, since it has an eccentric circular shape, it is possible to prevent relative rotation between the two while making the shape processing of the washer 150 and the fixing female screw body 130 extremely simple.

  In addition, although the case where the screw body side unevenness | corrugation 124 and the 1st receiving part side unevenness | corrugation 164 were saw-tooth shape was illustrated here as the 1st engagement mechanism A, this invention is not limited to this. For example, as shown in FIG. 30B, the unevenness of each other can be a mountain shape (both are inclined surfaces). Thus, when the engaging male screw body 110 rotates in the loosening direction X, the inclined surfaces 124X and 164X tend to move relative to each other. The side irregularities 164 are about to leave. If this moving distance (the angle α to leave) is set to be larger than the lead angle of the engaging male screw body 110, the screw body side unevenness 124 and the first receiving portion side unevenness 164 are further increased even if the engaging male screw body 110 tries to loosen. Will not be able to relax. In FIG. 30B, the unevenness of the isosceles triangle is illustrated as an example. However, as shown in FIG. 30C, the slopes of the inclined surfaces 124Y and 164Y that are in contact with each other at the time of fastening rotation are smaller than those at the time of loose rotation. It is also preferable to make the inclination angles of the inclined surfaces 124X and 164X in contact with each other gentle. In this way, the circumferential distance P between the inclined surfaces 124Y and 164Y that must be overcome during the fastening rotation can be shortened, so that looseness (gap) after fastening can be reduced.

  Moreover, as an application of FIGS. 30A to 30C, as shown in FIG. 30D, corrugated irregularities with curved ridges and valleys are also preferable. Smooth operability can be obtained during fastening. Furthermore, although the unevenness | corrugation extended in a radial direction was illustrated here, as shown to FIG. 31 (A), it is also preferable to form a spiral-shaped groove | channel or a peak (unevenness | corrugation). In addition, as shown in FIG. 31B, even a linearly extending groove or mountain (unevenness) can be inclined so that the circumferential phase changes with respect to the radial direction of the screw. Further, as shown in FIG. 31C, it is also preferable to adopt a so-called embossed shape in which a plurality of fine irregularities are formed both in the circumferential direction and the radial direction (planar shape) of the screw.

  Further, unlike the relative rotation prevention mechanism 40, the uneven shapes of the screw body side unevenness 124 and the first receiving portion side unevenness 164 are not necessarily matched (similar). For example, different shapes from the various shapes in FIGS. 30 and 31 can be selected and combined with each other.

  As an application of the relative rotation prevention mechanism 40, as shown in FIG. 32A, the outer wall of the second receiving portion 170 of the washer 150 and the inner wall of the fitting portion 184 of the member side pedestal portion 182 are the axial center of the screw. On the other hand, a concentric partial arc shape S can be used, and the rest can be cut into a straight line like the chord G. That is, also in this case, the distance from the axial center of the screw of the inner wall of the fitting portion 184 and the outer wall of the second receiving portion 170 varies along the circumferential direction. Therefore, the inner wall of the fitting portion 184 and the second receiving portion 170 are engaged by the shape of the string G, and relative rotation in the circumferential direction is restricted.

  As shown in FIG. 32B, the outer wall of the second receiving portion 170 of the washer 150 has a partial arc shape S concentric with the axial center of the screw, and a protrusion T extending in the radial direction is formed in the remaining portion. I can do it. At this time, a recess K recessed in the radial direction is formed on the inner wall of the fitting portion 184. By the engagement of the protrusion T and the recess K, the inner wall of the fitting portion 184 and the second receiving portion 170 are engaged, and the relative rotation in the circumferential direction is restricted. At this time, it is preferable that the recess K formed in the fitting portion 184 has a small perfect circular shape (partial arc). This is because, when the fitting portion 184 is cut, the depression K can be formed by only one processing with the rotary blade. Although not particularly illustrated, a recess (notch) may be formed on the second receiving portion 170 side of the washer 150, and a protrusion protruding radially inward may be formed on the fitting portion 184 side.

  According to the fastening structure 1 of the fourth embodiment, since the piston member 100 itself has the first female thread portion 106a and is screwed with the first male thread spiral groove 14 of the linear motion rod 10, it is externally provided. The piston member 100 itself can transmit the received force to the linear motion rod 10. The minimum diameter (valley diameter) of the first male screw spiral groove 14 is increased as compared with a conventional structure in which a piston member slidable in the axial direction is fixed to the linear motion rod 10 so as to be sandwiched between female screw bodies. Thus, the durability of the linear motion rod 10 can be increased.

  The male screw portion 13 of the linear rod 10 has a first male screw spiral groove 14 and a second male screw spiral groove 15, and a piston member is formed by a fixing female screw body 30 screwed into the second male screw spiral groove 15. Since the rotation in the loosening direction of 100 is regulated, the piston member 100 is not loosened even if repeated external force or vibration is applied to the piston member 100. In addition, unlike conventional loosening prevention, it does not rely on the frictional force between the flank surface of the male thread body and the flank surface of the female thread body. Since the structural interference is prevented from loosening due to the operation interference, it is not necessary to retighten the fixing female screw body 30 more than necessary, and the fatigue of the linear motion rod 10 can be reduced simultaneously with facilitating the fastening operation.

  Similarly, as long as the relative rotation prevention mechanism 40 does not come off or breakage occurs, even if the piston member 100 is plastically deformed or worn, a situation in which the piston member 100 falls off the linear motion rod 10 is not possible. It will be surely prevented and safety can be improved.

  The first male screw spiral groove 14 to which the piston member 100 is screwed and the second male screw spiral groove 15 to which the fixing female screw body 30 are screwed have a common minimum diameter (valley diameter). When the fixing member 100 and the fixing female screw body 30 are brought into close contact with each other, the external force acting on the piston member 100 is dispersed by the piston member 100 and the fixing female screw member 30 to the first male screw spiral groove 14 and the second male screw spiral groove 15. Can communicate. This also increases the durability of the linear motion rod 10.

  Further, in the present embodiment, the relative rotation preventing mechanism 40 completely prevents the relative rotation of the piston member 100 and the fixing female screw body 30. Therefore, only the fixing female screw body 30 rotates, and the linear motion rod 10 alone. To prevent it from coming off. In particular, in the relative rotation prevention mechanism 40, the engagement male screw body 110 itself that engages with the piston member 100 and the fixing female screw body 30 is also prevented from rotating in the loosening direction. There is no end. As a result, even if vibration or the like occurs, the function of the relative rotation prevention mechanism 40 is maintained, so that it is possible to prevent the piston member 100 from dropping from the linear motion rod 10.

  Further, when it is necessary to remove the piston member 100 at the time of maintenance or the like, the first engagement mechanism A between the washer 150 and the engaging male screw body 110 or the second between the washer 150 and the fixing female screw body 30 is used. One of the engagement mechanisms B is broken to remove the engaging male screw body 110, then the fixing female screw body 30 is removed, and then the fixing female screw body 30 is loosened. In this way, by limiting the destruction target at the time of maintenance to the washer 150 and the engaging male screw body 110, the piston member 100, the linear motion rod 10, and the fixing female screw body 30 can be reused. That is, according to the present embodiment, the piston member 100, the fixing female screw body 30, and the linear motion rod 10 can be easily and easily maintained while completely preventing displacement and dropping of the piston member 100 after assembly from the linear motion rod 10. It becomes possible to carry out at low cost. The material of the washer 150 or the engaging male screw body 110 is selected to be softer or relatively low in strength from the material of the piston member 100 or the fixing female screw body 30, thereby forcing the engaging male screw body 110 into force. It is also possible to preferentially break the washer 150 or the engaging male threaded body 110 during removal.

  Next, with reference to FIG. 33, the fastening structure which concerns on 5th embodiment of this invention is demonstrated. In addition, since it is the same as that of 4th embodiment except a relative rotation prevention mechanism, it demonstrates limiting to a relative rotation prevention mechanism here. In this relative rotation prevention mechanism, the engaging male screw body 110 is the same as that in the fourth embodiment, but the structures of the washer 150 and the fixing female screw body 130 are partially different. A description of the combined male screw body 110 is omitted.

  As shown in FIG. 34 (A), the washer 150 is thinner than the fourth embodiment, and also protrudes in the screw tip direction on the second receiving portion 170 side facing the fixing female screw body 30. A second washer-side tapered surface 176 is formed.

  As in the fourth embodiment, the outer wall 172 of the second receiving portion 170 of the washer 150 and the inner wall of the fitting portion 184 have an eccentric circular shape. Rotation is regulated.

  Returning to FIG. 33, a member-side tapered surface 186 that is concave on the screw tip side is formed on the bottom surface of the fitting portion 184 of the female screw body 130 for fixation. As a result, the fastening force of the male screw body 110 is received via the washer 150 by contacting the second washer-side tapered surface 176 of the washer 150.

  Further, a pulling space 188 is formed in a part of the inner wall of the fitting portion 184. The pulling space 188 is secured by expanding the inner wall of the fitting portion 184 radially outward and increasing the depth of the recess. The pulling space 188 forms a gap in a part of the outer wall of the second receiving part 170 of the washer 150.

  When the fixing female screw body 30 is fixed using the engaging male screw body 110 and the washer 150, the first engaging mechanism A serves as the screw body side unevenness 124 of the engaging male screw body 110 and the first receiving portion side on the washer 150 side. Concavities and convexities 164 engage. Further, as the second engagement mechanism B, the outer wall of the second receiving portion 170 of the washer 150 and the inner wall of the fitting portion 184 are fitted to each other, whereby circumferential rotation is restricted. As a result, the reverse rotation of the engaging male screw body 110 is prevented, i.e., does not loosen.

  FIG. 34B illustrates an operation for forcibly loosening the engaging male screw body 110 during maintenance. For example, by inserting the tip of the minus driver D into the pulling space 188, the tip is inserted into the back side of the washer 150. In this state, the second receiving part 170 of the washer 150 can be deformed upward by lifting the tip of the minus driver D. As a result, the second engagement mechanism B by the second receiving portion 170 and the fitting portion 184 is released. If the engaging male screw body 110 is rotated in the loosening direction in this state, the washer 150 can also be rotated together, so that the engaging male screw body 110 can be loosened.

  In the fifth embodiment, the case where the pulling space 188 is formed in the fitting portion 184 of the fixing female screw body 30 is illustrated, but the present invention is not limited to this. For example, as shown in FIG. 35A, by forming an inclined surface 177A on the outer wall of the washer 150, the tip of the minus driver D can be inserted into the back side of the washer 150 (the fixing female screw body 30 side). To. Further, as shown in FIG. 35B, an insertion recess 177B is formed on the periphery of the washer 150 so as to be away from the fixing female screw body 30. The tip of the minus driver D can be inserted into the back side of the washer 50 through the insertion recess 177B. In addition, a crescent-shaped gap is created by utilizing the difference in diameter between the outer diameter of the washer 150 and the inner diameter of the fitting portion 184, and this crescent-shaped gap (not shown) is used to It is also preferable that the tip can be inserted into the back side of the washer 150. Of course, such a gap is not limited to a crescent shape.

  Next, with reference to FIG. 36, the fastening structure which concerns on 6th embodiment of this invention is demonstrated. In addition, since it is the same as that of 4th embodiment except a relative rotation prevention mechanism, it demonstrates limiting to a relative rotation prevention mechanism here. As shown in FIG. 36 (B), the threaded body side seat portion 122 of the engaging male threaded body 110 has a planar shape, and a saw blade shaped threaded body side unevenness 124 is formed there. Further, a constriction 132 for holding the washer 150 is formed at the root of the shaft portion 130 of the engaging male screw body 110.

  As shown in FIG. 36A, the first receiving portion 160 of the washer 150 has a planar shape, and the first receiving portion side unevenness 164 having a saw blade shape is formed there. The insertion hole 152 of the washer 150 is formed with an engaging protrusion 152A that protrudes toward the inner peripheral side, and engages with the constriction 132 of the engaging male screw body 110. As a result, it is possible to integrate (couple) the engaging male screw body 110 and the washer 150 in advance.

  Further, a washer side step 174 extending in the axial direction of the screw is formed in the second receiving portion 170 of the washer 150. Here, the washer side stepped portion 174 is constituted by a claw bent toward the fixing female screw body 30 side.

  On the other hand, the fixing female screw body 30 has a flat surface portion 31a as the member side step portion 182A of the member side seat portion 182. The flat portion 31a also serves as the outer peripheral surface 31 of the hex nut. The member-side step 182A is a step that falls to the screw tip side. The distances from the screw shaft centers of the washer side step 174 and the member side step 182A coincide with each other. Therefore, as shown in FIG. 36 (C), when the male thread body 110 for engagement is tightened, the washer side step 174 and the member side step 182A are engaged, and the washer 150 and the fixing female thread body 30 are relatively rotated. Is prevented.

  In the sixth embodiment, the case where the two are integrated in advance by the constriction 132 of the engaging male screw body 110 and the engaging protrusion 152A of the washer 150 is illustrated, but the method is not limited to this. For example, it is possible to integrate the engaging male screw body 110 and the washer 150 by a magnetic force by giving magnetism to at least one of them. In addition, the engaging male screw body 110 and the washer 150 can be integrated in advance by an adhesive, (spot) welding, or press-fitting (frictional force). Further, it is possible to integrate the engaging male screw body 110 and the washer 150 using an auxiliary tool such as an O-ring.

  In the sixth embodiment, the outer peripheral surface 31 of the fixing female screw body 30 is engaged with the washer 150 to prevent relative rotation therebetween, but the present invention is not limited to this. For example, as in the application example shown in FIG. 37A, a shaft engaging portion 175 can be formed on the washer 150, and the shaft engaging portion 175 can be engaged with the male screw portion 13 of the linear rod 10. The shaft engaging portion 175 has a ring shape surrounding the male screw portion 13, and the washer 150 and the male screw portion 13 are engaged by inserting the male screw portion 13 into the shaft engaging portion 175. As a result, relative rotation of the washer 150 and the fixing female screw body 30 is prevented. The shape of the shaft engaging portion 175 is not limited to the ring shape, but engages with the male screw portion 13 such as a partial arc shape shown in FIG. 37B or a V shape sandwiching the male screw portion 13. Any possible shape can be selected. Further, as shown in FIG. 37 (C), two or more bolt insertion holes are provided for one washer 150, and rotation around the other bolt axis is prevented by two or more engaging male screw bodies 110. It is also possible to configure.

  Furthermore, although the case where the washer side step part 174 was formed in the outer periphery of the washer 150 was illustrated in 6th embodiment, this invention is not limited to this. For example, as shown in FIG. 37D, a washer side step (projection) 174 can be formed inside the outer edge of the washer 150. A member-side step (dent) 182 </ b> A that accommodates the washer-side step 174 is formed in the fitting portion 184 of the female screw body 30 for fixing. As a result, the washer side step (projection) 174 and the member side step (depression) 182A are engaged to prevent relative rotation.

  Next, with reference to FIG. 38, a fastening structure according to a seventh embodiment of the present invention will be described. In addition, since it is the same as that of 4th embodiment except a relative rotation prevention mechanism, it demonstrates limiting to a relative rotation prevention mechanism here. As shown in FIG. 38A, the outer shape of the washer 150 is a circular shape that is eccentric with respect to the axial center of the screw. The washer 150 is a so-called disc spring, and elastically deforms in the axial direction when receiving a fastening force from the engaging male screw body 110.

  As shown in FIG. 38B, the washer 150 is accommodated in an eccentric circular fitting portion 184 formed in the fixing female screw body 30. The threaded body side seat portion 122 of the engaging male threaded body 110 has a threaded body side unevenness 124 formed on the center side, and engages with the first receiving portion side unevenness 164 of the washer 150. Further, on the outer side of the screw body side unevenness 124 in the screw body side seat portion 122, a pressing surface 123 that directly contacts the fixing female screw body 30 is formed.

  Furthermore, the gap L between the bottom surface of the fitting portion 184 and the screw body side unevenness 124 of the engaging male screw body 110 is set to be slightly smaller than the axial dimension of the washer 150. As a result, when the engaging male screw body 110 is tightened, the washer 150 is elastically deformed by being sandwiched between the bottom surface of the fitting portion 184 and the screw body side unevenness 124. However, the amount of elastic deformation is sufficient to prevent relative rotation between the screw body side unevenness 124 and the first receiving portion side unevenness 164. This is because the fastening force of the engaging male screw body 110 is directly transmitted to the fixing female screw body 130 via the pressing surface 123. According to the present embodiment, the strength and rigidity of the washer 150 itself can be lowered, so that the manufacturing cost can be reduced.

  Further, in the fourth to seventh embodiments, the case where the head 120 of the engaging male screw body 110 protrudes from the fixing female screw body 30 is illustrated, but the depth of the fitting portion 184 of the fixing female screw body 30 is increased. Then, even the head 120 can be accommodated in the fitting portion 184.

  In the fourth to seventh embodiments, the outer shape of the washer 150 is exemplified only when it is a circle or a partial arc, but other shapes can be adopted. For example, the outer shape of the washer 150 may be oval, oval, polygonal or the like. In other words, in order to prevent relative rotation by fitting with the fitting portion, it is sufficient if the outer shape of the washer 150 is “non-perfect circle (not a concentric perfect circle)” with respect to the shaft center. In the seventh embodiment, the case where the washer 150 is elastically deformed as a disc spring is illustrated. However, the washer 150 can be elastically deformed like a spring washer. Furthermore, it is also preferable that a washer is formed of a composite material in which a metal and an elastically deformable material (for example, rubber) are integrated so as to be elastically deformable.

  Further, in the fourth to seventh embodiments, the washer 150 is installed on the fixing female screw body 30, and the first receiving portion side unevenness 164 is formed on the washer 150 b so as to be engaged with the screw body side unevenness 124 of the engaging male screw body 110. Although the structure to combine is illustrated, this invention is not limited to this. For example, as shown in FIG. 39, it is possible to directly form the first receiving portion side unevenness 164 on the plane of the fixing female screw body 30 and omit the washer 150. If the material strength of the fixing male screw body 30 is made stronger than that of the engaging male screw body 110, the first receiving portion of the fixing female screw body 30 even if the engaging male screw body 110 is forcibly loosened during maintenance or the like. The side irregularities 164 need not be damaged.

  Next, with reference to FIG. 40, the fastening structure which concerns on 8th embodiment of this invention is demonstrated. In addition, since it is the same as that of 4th embodiment except a relative rotation prevention mechanism, it demonstrates limiting to a relative rotation prevention mechanism here.

  As shown in FIG. 40A, the relative rotation preventing mechanism 40 includes a first engagement hole 191 that is a female screw hole formed in the piston member 100 and a second engagement hole that is formed in the female screw body 30 for fixation. 181, an engagement pin 111 as an engagement member, a spring 113 as an urging means, and a male screw body 115 for release. The second engagement hole 181 is an insertion hole, and includes a large diameter hole 181A formed on the piston member 100 side and a small diameter hole 181B formed on the shaft end side and smaller than the large diameter hole 181A. A release female screw portion 181C for screwing with the release male screw body 115 is formed on the inner peripheral surface of the small diameter hole 181B.

  The first engagement hole 191 formed in the piston member 100 is a non-insertion hole, and is set to have the same diameter as the large diameter hole 181A and longer than the large diameter hole 181A. The engagement pin 111 is a rod member having a diameter substantially coincident with the inner diameters of the first engagement hole 191 and the large diameter hole 181A, and is longer than the large diameter hole 181A and shorter than the first engagement hole 191. The spring 113 is housed on the back side (bottom side) of the first engagement hole 191 and biases the engagement pin 111 housed in the first engagement hole 191 toward the fixing female screw body 30 side. .

  Therefore, when the axial centers of the first engagement hole 191 and the large diameter hole 181A do not coincide with each other, the engagement pin 111 is completely accommodated in the first engagement hole 191 against the force of the spring 113. Is done. On the other hand, when the axial centers of the first engagement hole 191 and the large diameter hole 181A coincide, a part of the engagement pin 111 enters the large diameter hole 181A and stops by the urging force of the spring 113. As a result, the engaging pin 111 is inserted into the first engaging hole 191 and the second engaging hole 181 (large diameter hole 181A) at the same time, and the relative rotation of the piston member 100 and the fixing female screw body 30 is restricted. The

  When releasing the restriction by the engaging pin 111 during maintenance or the like, the release male screw body 115 is inserted into the small diameter hole 181B and screwed with the release female screw portion 181C. Since the length of the shaft portion of the male screw body for release 115 is substantially the same as the axial length of the female screw body for fixing 30, as shown in FIG. The combination pin 111 can be pushed into the first engagement hole 191 side, and the restriction of relative rotation by the engagement pin 111 can be released. Accordingly, if the release male screw body 115 is screwed into the small diameter hole 181B, the fixing female screw body 30 can be easily loosened.

  In the fourth to eighth embodiments, the structure in which the piston member 100 is disposed on the center side of the linear motion rod 10 and the fixing female screw body 30 is disposed on the end portion side of the linear motion rod 10 is illustrated. Is not limited to this. For example, as shown in FIG. 41, the piston member 100 may be disposed on the end portion side of the linear motion rod 10, and the fixing female screw body 30 may be disposed on the central side of the linear motion rod 10. In this case, the first insertion hole 35a1 having a large diameter and the second insertion hole 35a2 having a small diameter are coaxially provided inside the female screw body 30 for fixation, and the second insertion hole 35a2 has a second insertion hole on the inner peripheral surface thereof. A female thread portion 33 is formed. As a result, the stepped portion at the boundary between the first insertion hole 35a1 and the second insertion hole 35a2 is brought into contact with the end surface of the stopper 80, whereby the fixing male screw body 30 can be positioned in the axial direction. The relative rotation preventing unit 40 may be inserted by inserting the engaging male screw body 110 from the fixing female screw body 30 side toward the piston member 100, but on the contrary, from the piston member 100 to the fixing member. The structure may be such that the engaging male screw body 110 is inserted toward the female screw body 30.

  Furthermore, in the fourth to eighth embodiments, the case where the first male screw spiral groove 14 and the second male screw spiral groove 15 are formed so as to overlap the entire axial direction of the male screw portion 13 of the linear motion rod 10 is illustrated. However, the present invention is not limited to this. As shown in FIG. 42, for example, when the piston member 100 is disposed on the center side of the linear motion rod 10 and the fixing female screw body 30 is disposed on the end side, the first male screw spiral groove 14 to be screwed with the piston member 100 is a male screw. The second male screw spiral groove 15 to be screwed with the fixing female screw body 30 is an area where the fixing female screw body 30 is screwed, starting from the shaft end of the male screw portion 13, which is necessary throughout the axial direction of the portion 13. It suffices if it is formed up to the vicinity. That is, the male screw portion 13 of the present invention includes a case where the first male screw spiral groove 14 and the second male screw spiral groove 15 are formed so as to overlap each other in a limited region.

  Further, in the fourth to eighth embodiments, the case where the lead directions of the first male screw spiral groove 14 and the second male screw spiral groove 15 are different (a right screw and a left screw are used) is illustrated. It is not limited. For example, as shown in an enlarged view in FIG. 43, the first male screw spiral groove 14 and the second male screw spiral groove 15 may have the same screw direction (lead direction) and different leads (lead angles). Good. In this case, as shown in the figure, by forming a further spiral groove on the spiral thread 13a formed by the first male screw spiral groove 14, the first male screw spiral having a lead L1 (lead angle θ1). The second male screw spiral groove 15 having the groove 14 and the lead L2 (lead angle θ2) can be formed with the screw directions aligned.

  Furthermore, the male thread portion 13 of the linear motion rod 10 may not be formed by overlapping the first male thread spiral groove 14 and the second male thread spiral groove 15. For example, like the male screw portion 13 shown in FIG. 44, the first male screw spiral groove 14 has a large diameter, and the second male screw spiral groove 15 has a small diameter. It is also possible to arrange the second male screw spiral groove 15 so as not to overlap the end side. In this case, when the piston member 10 is screwed into the first male screw spiral groove 14, the second male screw spiral groove 15 is prevented from interfering in the diameter direction, and the fixing female screw body 30 is screwed into the second male screw spiral groove 15. In doing so, the first male screw spiral groove 14 may be prevented from interfering in the axial direction.

  Next, with reference to FIG. 45, the fastening structure which concerns on 9th embodiment of this invention is demonstrated. Since the relative rotation prevention mechanism is the same as that of the fourth embodiment, the description of the relative rotation prevention mechanism is omitted here, and only the parts different from the fourth embodiment will be described.

  In the present embodiment, an inner seal 82 formed of a chemical material such as a thermoplastic resin or a thermosetting resin is provided to the first shaft side step portion 11 a of the linear motion rod 10 via the metal expansion ring 11. The inner seal 82 itself also serves as a stopper for positioning the piston member 100 in the axial direction. The inner seal 82 may be directly engaged with the first shaft side step portion 11a, but in this case, the step of the first shaft side step portion 11a needs to be increased. Therefore, as in the present embodiment, the step of the first shaft side step portion 11a formed directly on the linear motion rod 10 is kept small, and the metal expansion ring 11 is engaged therewith, thereby substantially Increase the step.

  On the other hand, the first insertion hole 100 a 1 of the piston member 100 serves as an inner seal accommodation hole 250 that accommodates the inner seal 82. The inner seal 82 is formed with a tapered surface 82a that is narrowed toward the shaft end on the outer peripheral surface, and the inner peripheral surface of the inner seal accommodation hole 250 of the piston member 100 is a tapered surface facing this. Therefore, by screwing the piston member 100 onto the linear motion rod 10, the inner seal 82 and the inner seal accommodation hole 250 are pressed against each other, so that high sealing performance can be secured. In addition, although the case where the piston member 100 side was made into the taper surface was illustrated here, you may make it form a taper surface in the linear motion rod 10 side.

  Furthermore, in the present embodiment, an annular outer seal fitting portion 210 is formed on the outer peripheral surface of the piston member 100 from the middle to the end surface on the fixing female screw body 30 side. The outer seal fitting portion 210 is formed with a small-diameter surface 201 that continues to the end surface on the fixing male screw body 30 side on the peripheral surface. The small diameter surface 201 has a smaller diameter than the outer peripheral surface, and the seal ring 90 is installed there. The axial dimension of the seal ring 90 is set to be slightly larger than the axial dimension of the small-diameter surface 201 and protrudes from the piston member 100 to the fixing female screw body 30. The fixing female screw body 30 is set to have a diameter larger than that of the small-diameter surface 201 and has an outer diameter that is circular. Accordingly, when the fixing female screw body 30 is tightened to the piston member 100 side, the end face of the fixing female screw body 30 comes into contact with the seal ring 90 and the seal ring 90 is fixed. That is, the seal ring 90 is sandwiched between the piston member 100 and the fixing female screw body 30.

  As a result, it is possible to easily assemble the inner seal 82 and the seal ring 90 as compared with the conventional case where the seal material is installed while being elastically deformed. Accordingly, it is not necessary to consider the elastic deformation of the inner seal 82 and the seal ring 90, so that a material having high rigidity and high wear resistance can be selected. Although the case where the inner seal 82 has a taper structure is illustrated here, the inner peripheral surface of the seal ring 90 may be tapered surfaces 90a and 90b to improve the sealing performance as in the application example shown in FIG. it can. In this case, outer seal fitting portions 210 and 39 are formed on the outer peripheral surface of the piston member 100 and / or the fixing female screw body 30, and the inner peripheral surface of the seal ring 90 is tapered 90a and 90b on each peripheral surface. The taper surfaces 203 and 39a that face each other may be formed. Using the clamping force between the piston member 100 and the fixing female screw body 30, the taper surfaces 90a and 90b of the seal ring 90 and the taper surfaces 203 and 39a of the piston member 100 and / or the fixing female screw body 30 can be brought into close contact with each other. it can.

  In the fourth to ninth embodiments, the case where the engaging male screw body 110 is inserted from the fixing female screw body 30 side toward the piston member 100 side in the relative rotation preventing mechanism 40 is illustrated. However, the present invention is not limited thereto, and it may be inserted from the piston member 100 side toward the engaging male screw body 110 side. Further, in the fourth to ninth embodiments, the case where the relative rotation preventing mechanism 40 is arranged at one place in the circumferential direction is exemplified, but it may be arranged at a plurality of places in the circumferential direction.

  Furthermore, in the above-described embodiment, an example in which the piston coupling structure is applied to a hydraulic cylinder has been introduced. However, the present invention is not limited to this, and an appropriate fluid pressure is applied to the piston such as a hydraulic cylinder, an air cylinder, and various dampers. It can be applied to any linear motion system that obtains a desired motion by applying pressure or receiving pressure.

  Further, the embodiments of the present invention are not limited to the above-described embodiments, and it is needless to say that various modifications can be made without departing from the scope of the present invention. For example, the piston member of the present invention is provided with a small hole penetrating the front and back surfaces to form an orifice, and the input to the linear motion rod from the outside is attenuated by the flow of the viscous fluid accommodated inside the tube through the small hole. It can also be set as the structure made to act on.

DESCRIPTION OF SYMBOLS 1 Fastening structure 10 Linear motion rod 12 Shaft part 12a Main body part 12c End part 13 Male thread part 14 First male thread spiral groove 15 Second male thread spiral groove 17 Rod side cooperation area 20 Step part 22 Rod side seat part 23 Rod side contact part 23X Male screw side contact area 23Y Male screw side contact area 30 Fixing female screw body 31 Outer peripheral surface 31a of fixing female screw body Flat surface portion 33 of fixing female screw body Second female screw part 40 Relative rotation prevention mechanism 50 Cooperation member (washer, piston )
52 Insertion hole 53 Washer-side contact part 53X First washer-side contact area 53Y Second washer-side contact area 60 First receiving part 64 First receiving part side unevenness 70 Second receiving part 100 Piston member 100a Insertion hole 102 Seat Part 104 Screw body side unevenness 105a Seal part 106a (First) Female thread part 106b Piston side cooperation area 108 Female thread side contact part 110 Engaging male threaded body 111 Engaging pin 115 Release male threaded body 150 Washer 181 Second engaging hole 191 First One engagement hole 201 Small diameter surface 203 Tapered surface 210 Outer seal fitting portion 250 Inner seal accommodation hole C Axle (screw shaft)

Claims (24)

A piston member which is accommodated in the tube so as to be movable in the axial direction, is fixed to the linear motion rod in the tube, receives the pressure of the fluid, and transmits the fluid to the linear motion rod;
A seal portion that is formed on the outer peripheral surface facing the inner peripheral surface of the tube and restricts the movement of the fluid in the vicinity of the inner peripheral surface;
A pressure receiving surface that is formed on at least one of the pair of end faces facing in the axial direction and receives the pressure of the fluid;
An insertion hole into which the linear motion rod is inserted,
The insertion hole is formed with a female screw portion that is screwed with a male screw portion of the outer peripheral surface of the linear motion rod,
The insertion hole has a larger diameter than the female screw portion and has an annular inner seal accommodation hole that continues to the end surface. An annular inner seal member can be disposed in the inner seal accommodation hole. And
The peripheral surface of the inner seal housing hole has a taper structure in which the male screw portion side has a small diameter and the end surface side has a large diameter,
Piston member. The outer peripheral surface is
It has a smaller diameter than the seal part, and has an annular outer seal fitting part that continues to the end surface,
The outer seal fitting portion is configured so that an annular outer seal member can be arranged.
The piston member according to claim 1. The peripheral surface of the outer seal fitting portion has a taper structure in which the seal portion side has a large diameter and the end surface side has a small diameter,
The piston member according to claim 2. A piston member which is accommodated in the tube so as to be movable in the axial direction, is fixed to the linear motion rod in the tube, receives the pressure of the fluid, and transmits the fluid to the linear motion rod;
A seal portion that is formed on the outer peripheral surface facing the inner peripheral surface of the tube and restricts the movement of the fluid in the vicinity of the inner peripheral surface;
A pressure receiving surface that is formed on at least one of the pair of end faces facing in the axial direction and receives the pressure of the fluid;
An insertion hole into which the linear motion rod is inserted,
The insertion hole is formed with a female screw portion that is screwed with a male screw portion of the outer peripheral surface of the linear motion rod,
The outer peripheral surface has an annular outer seal fitting portion that has a smaller diameter than the seal portion and continues to the end surface, and an annular outer seal member is disposed in the outer seal fitting portion. Configured and possible
The peripheral surface of the outer seal fitting portion has a taper structure in which the seal portion side has a large diameter and the end surface side has a small diameter,
Piston member. In the insertion hole or the end face,
An annular tapered surface for centering with the linear rod or the external member is formed,
The piston member according to claim 4. The insertion hole is
It has a larger diameter than the female screw part, and has an annular inner seal accommodation hole that continues to the end surface,
An annular inner seal member is configured to be disposed in the inner seal accommodation hole.
The piston member according to claim 4. The peripheral surface of the inner seal housing hole has a taper structure in which the male screw portion side has a small diameter and the end surface side has a large diameter,
The piston member according to claim 6. The end face is provided with a relative rotation prevention mechanism capable of engaging in the circumferential direction with respect to the linear motion rod or an external member fastened to the linear motion rod.
The piston member according to any one of claims 1 to 7 . The relative rotation prevention mechanism has an engagement hole that houses an engagement member that engages with the linear motion rod or the external member.
The piston member according to claim 8. The relative rotation prevention mechanism abuts on the linear motion rod or the external member, and allows relative movement with the linear motion rod or the external member for rotation in a direction in which the female thread portion is tightened. For rotation in the direction of loosening, the relative movement with the linear motion rod or the external member is restricted,
The piston member according to claim 8 or 9. In the insertion hole, a piston side cooperation region having a non-circular cross section when viewed from the axial direction is formed,
The piston member according to any one of claims 1 to 10. The minimum distance from the axis of the piston side cooperation region is larger than the minimum distance from the axis of the female screw portion,
The piston member according to claim 11. The piston side cooperation region is engaged with the shaft portion of the linear motion rod in the circumferential direction,
The piston member according to claim 11 or 12. The piston-side cooperation region is elastically deformable in the radial direction,
The piston member according to claim 11. A linear motion system comprising: the piston member according to any one of claims 1 to 14; and the linear motion rod that holds the piston member and interlocks with a reciprocating movement of the piston member. A fastening structure of the piston member,
The male thread portion formed on the linear rod and formed with a first male thread spiral groove and a second male thread spiral groove having different lead angles and / or lead directions;
A first female thread portion formed on the piston member, having the first female thread spiral groove corresponding to the first male thread spiral groove, and configured to be able to be screwed into the first male thread spiral groove;
A female screw body for fixing having a second female screw spiral groove corresponding to the second male screw spiral groove and configured to be able to be screwed into the second male screw spiral groove;
Characterized by comprising,
Piston fastening structure. In the male screw portion, the first male screw spiral groove and the second male screw spiral groove are formed so as to overlap at least in a region,
The piston fastening structure according to claim 15. An engaging member that is simultaneously inserted into a first engaging hole formed in the piston member and a second engaging hole formed in the female screw body for fixing; and the piston member and the fixing are fixed by the engaging member. Characterized in that it comprises a relative rotation prevention mechanism for regulating the relative rotation of the female screw body for
The piston fastening structure according to claim 15 or 16. The relative rotation prevention mechanism is
An engaging female thread portion formed on the inner peripheral surface of at least one of the first engaging hole and the second engaging hole;
An engaging male threaded body that functions as the engaging member by screwing with the engaging female thread part;
A washer into which the male screw body for engagement is inserted,
The male threaded body for engagement has a threaded body side seat portion facing the washer,
The washer includes a first receiving portion facing the screw body side seat portion, and a second receiving portion facing the fixing female screw body or the piston member,
The internal thread body for fixing or the piston member has a member side seat portion facing the second receiving portion,
A first engagement mechanism is configured between the screw body side seat portion and the first receiving portion so that the screw body side seat portion is maintained in an engaged state even when a rotational force in a specific direction acts on the screw body side seat portion. And
Between the member side seat portion and the second receiving portion, a second engagement mechanism is formed that maintains a state where the washers are engaged with each other even if a rotational force in the specific direction acts on the washer. It is characterized by
The piston fastening structure according to claim 17. The relative rotation prevention mechanism is
An engaging female thread portion formed on the inner peripheral surface of at least one of the first engaging hole and the second engaging hole;
An engaging male threaded body that functions as the engaging member by screwing with the engaging female thread part;
A member side seat portion formed on the fixing female screw body or the piston member,
The male threaded body for engagement has a threaded body side seat portion facing the member side seated portion,
An engagement mechanism is formed between the screw body side seat portion and the member side seat portion so that the screw body side seat portion is kept engaged even when a rotational force in a specific direction acts on the screw body side seat portion. It is characterized by
The piston fastening structure according to claim 17. The relative rotation prevention mechanism is
An engagement pin which is arranged so as to be movable in the axial direction inside the first engagement hole and the second engagement hole and functions as the engagement member;
An urging means that is accommodated in the first engagement hole or the second engagement hole and urges the engagement pin;
The piston fastening structure according to claim 17. In the shaft portion having the male screw portion, a linear motion rod in which a rod side cooperation region having a non-circular cross section when viewed from the axial direction is formed;
The piston member according to any one of claims 1 to 14, wherein the piston member is screwed with the male thread portion of the linear motion rod.
An association member in which an insertion hole through which the male screw portion can be inserted is formed, and the insertion hole is engaged with the rod side association region in the circumferential direction by being a non-circular shape, and the piston member and the periphery A piston fastening structure comprising: a cooperating member characterized by having a relative rotation preventing mechanism that engages in a direction. The cooperation member has the relative rotation prevention mechanism with the piston member on both surfaces in the axial direction,
The piston fastening structure according to claim 21, wherein the piston member is disposed on both sides in the axial direction of the cooperation member so that the piston member is engaged with the cooperation member in a circumferential direction. In the shaft portion having the male screw portion, a linear motion rod in which a rod side cooperation region having a non-circular cross section when viewed from the axial direction is formed;
The piston member according to any one of claims 1 to 14, wherein a piston-side cooperation region having a non-circular cross section when viewed in the axial direction is formed in the insertion hole having a female screw portion that is screwed with the male screw portion. With
The rod-side linkage region and the piston-side linkage region are configured to engage with each other in the circumferential direction while allowing relative rotation by an external force. A linear rod having a shaft portion having a male screw portion;
The piston member according to any one of claims 1 to 14, wherein the piston member is screwed with the male thread portion of the linear motion rod.
A piston fastening structure, comprising: a relative rotation prevention mechanism that is integrally formed with the shaft portion of the linear motion rod and engages with the piston member in a circumferential direction.