JP2013079692A - Flow rate control valve - Google Patents

Abstract

In a pressure compensated flow control valve, leakage of hydraulic fluid through a gap between an outer periphery of a spool and an inner periphery of a body is reduced.
An annular sheet member 5 that restricts a sliding range of a spool 3 is provided in a body 1 and an inclined surface 321 that is inclined with respect to an axial direction at an end 32 of the spool 3 that contacts the sheet member 5 is provided. And an edge 53 that makes line contact with the inclined surface 321 is formed on the sheet member 5 to construct a seal structure that suppresses the hydraulic fluid from entering the spring chamber and leaking into the tank line 63. Furthermore, an inclined surface 51 that is inclined with respect to the axial direction is formed on the sheet member 5, and an edge 15 that is in line contact with the inclined surface 51 is formed on the body 1, so that the hydraulic fluid flows between the sheet member 5 and the body 1. A seal structure was constructed to prevent entry into the gap and leakage into the tank line 63.
[Selection] Figure 2

Description

  The present invention relates to a flow control valve used for hydraulic devices such as various industrial machines and vehicles.

  A pressure-compensated flow control valve that can keep the flow rate constant even when the fluid pressure fluctuates is known (see, for example, Patent Document 1 below). This type of flow control valve is configured such that a control spool is slidably disposed in a cylindrical body, and a spring that elastically biases the spool in the axial direction is interposed between the body and the spool. . When the upstream fluid pressure increases, the pressure in the valve chamber increases as the high-pressure fluid flows in, and the spool is displaced along the axial direction against the elastic biasing force of the spring. As a result, the opening degree of the variable orifice on the inlet side is reduced, pressure compensation is performed, and the flow rate of the fluid flowing out downstream is kept constant.

  It is desirable that the hydraulic pressure of the hydraulic fluid introduced into the spring chamber in which the spring is disposed in the body is constantly constant. For this purpose, it is conceivable that the spring chamber is always in communication with a tank line or the like through which hydraulic fluid that circulates toward the tank flows.

  However, when taking such an aspect, the hydraulic fluid flowing into the body leaks into the spring chamber through the gap between the outer periphery of the spool and the inner periphery of the body, and flows down toward the tank via the communication path. There was a problem that caused the problem.

  Although it is conceivable to install an O-ring as a seal on the outer periphery of the spool or the inner periphery of the body in order to prevent leakage of the hydraulic fluid, both the spool and the body are thin, so that the O-ring is inserted. It was difficult to form the concave groove.

  Incidentally, there is known a poppet valve having a structure in which the valve body is tapered in a truncated cone shape, and the valve body is in line contact with the valve seat over substantially the entire circumference around the shaft center (for example, the following patents) Reference 2). That is, when it is necessary to cut off the flow of the working fluid, the poppet valve body is brought into close contact with the valve seat, thereby completely isolating the inflow port from the outflow port of the body.

  However, it is not disclosed in any of the following patent documents that an annular sheet member is inserted and fixed in the body.

JP 2009-036336 A Japanese Utility Model Publication No. 63-090661

  An object of the present invention is to reduce leakage of hydraulic fluid through a gap between an outer periphery of a spool and an inner periphery of a body in a pressure compensation flow control valve.

  In the present invention, a pressure-compensated flow rate control in which a spool that receives the pressure of hydraulic fluid (for example, oil) flowing into the body slides along the axial direction in the body to reduce the opening of the variable orifice. A spring chamber in which a spring that elastically biases the spool in the body is disposed is communicated with a predetermined hydraulic fluid flow path outside the body that is different from the outlet through which the hydraulic fluid whose pressure is compensated flows. One of a communicating path, an annular seat member whose one end is disposed closer to the spool than the communicating path in the body and restricts a sliding range of the spool, and a portion of the spool that contacts the sheet member and the sheet member The working fluid that has flowed into the body enters the communication path, and has an inclined surface that is formed in the direction inclined with respect to the axial direction and an end that is formed on the other side and that is in line contact with the inclined surface. An inclined surface that is formed on one of the first sealing structure to be suppressed, and the seat member and a body part that is in contact with the seat member, and is inclined with respect to the axial direction, and is formed on the other and is lined with the inclined surface. The flow rate control valve is characterized by comprising a second seal structure that uses the contact edge as an element and suppresses the hydraulic fluid flowing into the body from entering the communication path.

  According to the present invention, leakage of hydraulic fluid through the gap between the outer periphery of the spool and the inner periphery of the body can be reduced.

The side sectional view showing the flow control valve of one embodiment of the present invention. The sectional side view which shows the flow control valve of the embodiment. The sectional side view which shows the usage example of the flow control valve of the embodiment.

  An embodiment of the present invention will be described with reference to the drawings. A flow control valve 0 of this embodiment shown in FIGS. 1 and 2 is incorporated in a housing block or the like of a hydraulic device, and includes a body 1, a plug 2, a control spool 3, a spring 4, and a seat member 5 as main components. It is a component.

  The body 1 has a cylindrical shape in which one end is closed and the other end is opened, and the spool 3 is slidably held in the axial direction in the body 1. An inflow port 11, a fixed throttle 12, an outflow port 13 and a communication hole 14 are formed in the peripheral wall of the body 1.

  The inflow port 11 is a variable orifice whose opening area is expanded and contracted by sliding of the spool 3, and is connected to a flow path 61 through which hydraulic fluid with indefinite pressure flows, and allows hydraulic fluid to flow into the body 1 from the upstream side. In addition to the inlet 11, the fixed throttle 12 is connected to a flow path 61 through which hydraulic fluid with indefinite pressure flows, and also allows hydraulic fluid to flow into the body 1 from the upstream side. The fixed throttle 12 is a throttle hole that is narrower than the inlet 11.

  The outlet 12 is connected to the flow path 62 through which the hydraulic fluid whose pressure is compensated flows, and allows the hydraulic fluid that has flowed into the body 1 through the inlet 11 and the fixed throttle 12 to flow downstream.

  The communication hole 14 is connected to a hydraulic fluid channel 63 different from the channel to which the inlet 11 and the outlet 13 are connected, and allows the hydraulic fluid to flow into the body 1 from the channel 63. The flow path 63 is a flow path in which the pressure of the hydraulic fluid is constantly constant, for example, a tank line directly connected to a hydraulic fluid tank (not shown).

  The inflow port 11, the fixed throttle 12, the outflow port 13, and the communication hole 14 are each intermittently drilled on substantially the same circumference around the axis. The inflow port 11 exists near one end of the body 1, the fixed restrictor 12 exists at a position slightly deviated from the inflow port 11 toward the other end, and the outflow port 13 exists at a position slightly deviated from the fixed restrictor 12 toward the other end. The communication hole 14 exists at a location that is further deviated from the outlet 13 toward the other end.

  The inner diameter of the body 1 is slightly smaller at one end half than at the other end, and there is a step between the one end half and the other end half. The other half of the other end constitutes a spring chamber that houses a spring 4 described later. The inflow port 11, the fixed throttle 12 and the outflow port 13 are provided on one end side having a relatively small inner diameter, and the communication hole 14 is provided on the other end side having a relatively large inner diameter.

  A plug 2 is screwed to the other end of the body 1 to close it.

  The spool 3 has an outer shape in which an annular recess 331 is formed between the one end portion 31 and the other end portion 32 to reduce the diameter of the intermediate portion 33. The outer circumferences of the one end 31 and the other end 32 of the spool 3 are substantially in close contact with the inner circumference of the body 1.

  A pressure transmission hole 311 that opens to one end surface is provided inside the one end portion 31. The pressure transmission hole 311 communicates with the annular recess 331 through the internal passage 332 of the intermediate portion 33.

  The other end 32 is formed with a taper 321 that gradually decreases in diameter toward the other end. The taper 321 is an inclined surface that is continuous over the entire circumference around the axis and is inclined with respect to the axis direction. The end of the taper 321 is cut off so that the taper 321 forms a truncated cone shape, and the support shaft 322 protrudes along the axial direction from the center portion of the end surface facing the axial direction.

  The spring 4 that elastically biases the spool 3 has one end elastically in contact with the end surface connected to the terminal end of the taper 321 of the spool 3 and the other end elastically in contact with the inward surface of the plug 2. By this spring 4, the spool 3 is elastically biased toward one end. The support shaft 322 is inserted into the inner space of the coil spring 4 and serves as a retainer that holds the spring 4. Incidentally, the support shaft 21 protrudes along the axial direction so as to face the support shaft 322 also from the inward surface of the plug 2, and is inserted into the inner space of the coil spring 4 to function as a retainer.

  One end portion 31 of the spool 3 opens and closes the inlet 11 serving as a variable orifice. The hydraulic fluid that has flowed into the body 1 from the inflow port 11 or the fixed throttle 12 reaches the outflow port 13 via the annular recess 331 and flows out from there.

  The elastically biased spool 3 has its one end face in contact with or close to the inward face of the body 1 at the initial position shown in FIG. At the stage where the spool 3 is at the initial position, the inflow port 11 is fully open.

  When the upstream pressure (that is, the fluid pressure in the flow path 61) rises, the inlet 11 opens the valve chamber, that is, the annular recess 331, the pressure transmission hole 311, and the gap between one end surface of the spool 3 and the inward surface of the body 1. The fluid pressure that flows in presses the spool 3 toward the other end. Then, as shown in FIG. 2, the spool 3 is displaced against the elastic biasing force of the spring 4. As the spool 3 is displaced from the initial position, the opening area of the inflow port 11 is gradually reduced, so that the spool 3 has a valve chamber pressure (that is, a liquid pressure in the annular recess 331) and a downstream pressure (that is, It stops at a position where the pressure difference with the fluid pressure of the flow path 62 matches a given compensation pressure. In this way, the flow rate of the hydraulic fluid flowing from the upstream to the downstream is kept constant.

  Therefore, in the present embodiment, the seat member 5 that restricts the sliding range of the spool 3 is provided in the body 1. The sheet member 5 in the present embodiment is separate from the body 1, the plug 2, the spool 3, and the like. The sheet member 5 is an annular body whose outer periphery is in close contact with the inner periphery of the other half of the body 1.

  A through hole 52 that is continuous with the communication hole 14 is formed at a location facing the communication hole 14 formed in the body 1 in the seat member 5. Both the communication hole 14 and the through hole 52 serve as a communication path that allows the spring chamber to communicate with the tank line 63 outside the body 1. Since the spring chamber communicates with the tank line 63, the fluid pressure in the spring chamber is made substantially uniform regardless of the fluid pressure upstream of the flow control valve 0.

  A taper 51 that is gradually reduced in diameter toward one end is formed at the end on one end of the sheet member 5. The taper 51 is an inclined surface that is continuous over the entire circumference around the axis and is inclined with respect to the axial direction. The end of the taper 51 is cut off so that the taper 51 forms a truncated cone shape.

  When the plug 2 is screwed after the sheet member 5 is disposed in the body 1, the inward surface of the plug 2 comes into close contact with the other end surface of the sheet member 5. Further, the taper 51 on one end side of the sheet member 5 is a stepped portion between the half portion on one end side and the half portion on the other end side of the body 1, more specifically, the inner peripheral surface of the half portion on one end side and the axial direction. It closely adheres to the edge 15 where the stepped surface facing the surface intersects. The end edge 15 is continuous over the entire circumference around the axis. Accordingly, the contact between the taper 51 and the end edge 15 is a line contact that makes contact over substantially the entire circumference around the axis.

  Further, when the upstream hydraulic pressure becomes very large and the spool 3 is displaced to the limit position of its sliding range as shown in FIG. 2, the taper 321 at the other end 32 of the spool 3 The member 5 is in close contact with the edge 53 where the inner peripheral surface of the member 5 and the one end surface facing the axial direction intersect. The edge 53 is continuous over the entire circumference around the axis. Therefore, the contact between the taper 321 and the end edge 53 is a line contact that makes contact over substantially the entire circumference around the axis.

  There is a fine gap between the outer periphery of the spool 3 and the inner periphery of the body 1. The hydraulic fluid flowing into the body from the inlet 11 or the fixed throttle 12 may have a high pressure, and this hydraulic fluid flows into the spring chamber through a gap between the outer periphery of the spool 3 and the inner periphery of the body 1, That is, the tank line 63 may leak through the through hole 52 and the communication hole 14.

  On the other hand, in the first seal structure based on the line contact between the taper 321 and the edge 53, the hydraulic fluid that has passed through the gap between the outer periphery of the spool 3 and the inner periphery of the body 1 passes through the inner space of the sheet member 5. To flow into the spring chamber and reach the communication path.

  In addition, the second seal structure by the line contact between the taper 51 and the edge 15 is such that the hydraulic fluid that has passed through the gap between the outer periphery of the spool 3 and the inner periphery of the body 1 It is prevented from entering between the circumference and reaching the communication path (communication hole 14).

  FIG. 3 is a usage example of the flow control valve 0 of the present embodiment. The flow control valve 0 is downstream of the cylinder port 64 and the hydraulic fluid passage 61 connected to a hydraulic cylinder (not shown), and maintains a constant flow rate of the hydraulic fluid flowing out from the hydraulic cylinder. Regardless of the magnitude of the load that the piston receives, it plays the role of stabilizing the movement speed of the piston. That is, the hydraulic fluid flowing down from the hydraulic cylinder flows into the flow path 61 from the cylinder port 64, reaches the flow path 62 via the flow rate control valve 0, and finally goes to the hydraulic fluid tank.

  In order to maintain the pressure in the hydraulic cylinder and fix the piston, that is, to realize a state where hydraulic fluid does not flow down from the hydraulic cylinder, the lift spool 7 downstream of the flow control valve 0 is operated to operate FIG. The downstream position 62 connected to the outlet 13 of the flow control valve 0 is closed. Due to the seal structure inside the flow control valve 0, the hydraulic fluid in the cylinder is prevented from leaking from the flow control valve 0 to the tank line 63 instead of the downflow path 62. Therefore, the piston does not move unexpectedly.

  According to this embodiment, the spool 3 that has received the pressure of the hydraulic fluid flowing into the body 1 slides along the axial direction in the body 1 to reduce the opening of the variable orifice 11. A flow control valve 0, in which a spring 4 that elastically biases the spool 3 in the body 1 is disposed, a predetermined outside of the body 1 different from the outlet 13 through which the pressure-compensated hydraulic fluid flows out. Communication passages 52 and 14 communicating with the hydraulic fluid flow path 63, and an annular seat member 5 whose one end is disposed closer to the spool 3 than the communication passage 1 in the body 1 and restricts the sliding range of the spool 3. The body includes a sloped surface 321 formed at a portion 32 of the spool 3 that contacts the sheet member 5 and inclined with respect to the axial direction, and an edge 53 formed on the sheet member 5 and in line contact with the sloped surface 321 as elements. A first seal structure that suppresses the hydraulic fluid that has flowed into the communication passages 52 and 14, an inclined surface 51 that is formed in the seat member 5 and is inclined with respect to the axial direction, and the body 1, the edge 15 formed at the boundary between the half on one end side and the half on the other end side is in contact with the inclined surface 51 as an element, and the hydraulic fluid that has flowed into the body 1 flows into the communication path 52, Since the flow control valve 0 provided with the second seal structure that suppresses the intrusion into the 14 is configured, the leakage of the hydraulic fluid through the gap between the outer periphery of the spool 3 and the inner periphery of the body 1 can be reduced. .

  The present invention is not limited to the embodiment described in detail above. In the above embodiment, the first seal structure is constructed by providing the end surface 32 of the spool 3 with the inclined surface 321 and the sheet member 5 with the end edge 53 in close contact with the inclined surface 321. Alternatively, the sheet member 5 may be provided with an inclined surface, and the end 32 of the spool 3 may be provided with an edge closely contacting the inclined surface.

  In addition, in the above embodiment, the seat member 5 is provided with the inclined surface 51, and the edge portion 15 in close contact with the inclined surface 51 is provided at the step portion on the inner periphery of the body 1, thereby constructing the second seal structure. On the contrary, an inclined surface may be provided at the step portion on the inner periphery of the body 1 and an edge that closely contacts the inclined surface may be provided on the sheet member 5.

  In the above embodiment, the inflow port 11 is a variable orifice, but it does not prevent the outflow port 13 from being a variable orifice together with or in place of the inflow port 11. In this case, the outlet 13 is gradually closed by the spool 3 and the opening area thereof is reduced as the spool 3 that receives the hydraulic pressure is displaced from the initial position against the elastic biasing force.

  It is also conceivable that the sheet member 5 that regulates the sliding range of the spool 3 is formed integrally with the body 1. However, in this case, the second seal structure does not exist. In addition, for the work of inserting the spool 3 into the body 1, one end of the body 1 is opened, and after inserting the spool 3 from one end side of the body 1, a plug or the like is attached to one end of the body 1. It is necessary to close this.

  Other specific configurations of each part can be variously modified without departing from the spirit of the present invention.

  The present invention can be used for hydraulic devices such as various industrial machines and vehicles.

0 ... Flow control valve 1 ... Body 14 ... Communication passage (communication hole)
15 ... edge 3 ... spool 321 ... inclined surface (taper)
4 ... Spring 5 ... Sheet member 51 ... Inclined surface (taper)
52 ... Communication passage (through hole)
53 ... Edge 63 ... Predetermined hydraulic fluid flow path (tank line)

Claims (1)

A pressure-compensated flow control valve in which a spool that receives the pressure of hydraulic fluid flowing into the body slides along the axial direction in the body to reduce the opening of the variable orifice,
A communication passage for allowing a spring chamber in which a spring for elastically urging the spool in the body is arranged to communicate with a predetermined hydraulic fluid flow path outside the body different from the outlet through which the pressure-compensated hydraulic fluid flows out;
An annular seat member, one end of which is disposed closer to the spool than the communication path in the body and restricts the sliding range of the spool;
The sheet member and the portion of the spool that contacts the sheet member are formed on one side and an inclined surface that is inclined with respect to the axial direction, and the other edge that is formed on the other side and in line contact with the inclined surface is an element. A first seal structure for suppressing hydraulic fluid flowing into the body from entering the communication path;
The sheet member and an inclined surface formed on one of the body parts contacting the sheet member and inclined with respect to the axial direction, and an edge formed on the other and in line contact with the inclined surface, are used as elements. A flow rate control valve comprising: a second seal structure that suppresses the hydraulic fluid flowing into the body from entering the communication passage.

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