JP7665580B2 - Pressure Regulating Valve - Google Patents

Description

The present invention relates to a pressure regulating valve equipped with an adjustment spring and a pressure-sensitive member.

In pressure regulating valves, an adjustment spring and a pressure-sensitive member have been provided to control the valve opening in response to pressure fluctuations.

For example, as shown in FIG. 11(a), Patent Document 1 describes a pressure regulating valve 1100 (hereinafter referred to as a "conventional pressure regulating valve") that includes a valve body 1105 having a valve seat 1118, a needle 1130 having a valve portion 1132 that can be attached to and detached from the valve seat 1118, a pressure-sensing unit 1140 having a pressure-sensing bellows 1141 that biases the valve portion 1132 in the axial direction, and an adjustment spring unit 1150 having an adjustment spring 1153 that biases the valve portion 1132 in the valve closing direction.

JP 2022-134450 A

As shown in FIG. 11(b), in a conventional pressure regulating valve, the effective pressure receiving area S1' of the pressure sensing bellows 1141 is made to match the pressure receiving area S2' of the valve portion 1132 surrounded by the valve seat 1118, thereby canceling the effects of the secondary pressure P2 acting on the pressure sensing bellows 1141 and the valve portion 1132. This allows the valve opening pressure to be set by adjusting the biasing force of the adjustment spring 1153, thereby controlling the valve opening in response to fluctuations in the primary pressure.

However, the pressure-sensitive bellows 1141 is manufactured by a molding method (roll forming, press molding, hydroforming, etc.) that has a relatively large variation in processing tolerances. Therefore, the effective pressure-receiving area S1' of the pressure-sensitive bellows 1141 varies widely, and it has been extremely difficult to match the effective pressure-receiving area S1' to the pressure-receiving area S2' of the valve section 1132 surrounded by the valve seat 1118, that is, to match the average inner diameter D1' of the pressure-sensitive bellows 1141 to the valve port diameter D2' of the valve housing 1110.

In addition, when matching the average inner diameter D1' of the pressure-sensitive bellows 1141 to the valve port diameter D2' of the valve housing 1110, a pressure-sensitive bellows having the desired average inner diameter is selected from among pressure-sensitive bellows having existing molding dies (the average inner diameter of the pressure-sensitive bellows is known), but the average inner diameter D1' of the pressure-sensitive bellows 1141 has a minimum diameter limit due to the molding method.

Therefore, for example, even when a conventional pressure regulating valve is required to be used at a small flow rate, the valve port diameter D2' must be increased in order to match the average inner diameter D1' of the pressure-sensing bellows 1141, resulting in restrictions on the lower limit of the applicable flow control range and the degree of freedom in design.

As a result of the above, with conventional pressure regulating valves, it was not possible to cancel the effects of the secondary pressure P2 acting on the pressure-sensing bellows 1141 and the valve portion 1132, and a problem arose in which the valve opening pressure changed significantly as the secondary pressure P2 varied (hereinafter referred to as "conventional problem (changes in valve opening pressure due to secondary pressure)").

The object of the present invention is to provide a pressure regulating valve that can reliably suppress changes in valve opening pressure caused by secondary pressure, even when the needle has processing tolerances, by adjusting the outer diameter of the needle seal portion instead of the average inner diameter of the pressure-sensitive bellows.

To solve the above problem, the pressure regulating valve includes a valve body having a valve port, a needle having a valve portion that can be attached to and detached from the valve port, a pressure-sensing unit having a pressure-sensing member that bends along the axial direction and urges the valve portion, an adjustment spring unit having an adjustment spring that urges the valve portion in a valve closing direction via the pressure-sensing unit, a valve chamber in which the valve portion is disposed and into which secondary pressure is introduced, a back pressure chamber located on the adjustment spring unit side of the needle and housing the pressure-sensing member, a pressure introduction passage that communicates the valve port and the back pressure chamber to introduce primary pressure into the back pressure chamber, and a seal member that is provided in the needle seal portion of the needle and that separates the back pressure chamber from the valve chamber, and the outer diameter of the needle seal portion and the valve port diameter are formed to be approximately the same.

In the above pressure regulating valve, the pressure introduction passage may be provided in the valve body.

The pressure regulating valve may further include a coupling connector between the valve body and a primary coupling that introduces the primary pressure into the valve port, and at least one of the valve body and the coupling connector may have a communication recess that communicates with the pressure introduction passage.

In the pressure regulating valve, the primary side fitting that introduces the primary side pressure into the valve port may include a base and a joint that has an inner diameter larger than the inner diameter of the base and communicates with the pressure introduction passage.

In the pressure regulating valve, the outer diameter of the needle seal portion may be slightly larger than the valve port diameter.

According to the present invention, by adjusting the outer diameter of the needle seal portion instead of the average inner diameter of the pressure-sensitive bellows, it is possible to provide a pressure regulating valve that can reliably suppress changes in valve opening pressure due to secondary pressure, even when the needle has processing tolerances.

1 is a cross-sectional view showing a pressure regulating valve according to a first embodiment of the present invention in a valve closed state. FIG. 2 is a partially enlarged view of region II in FIG. 1 . 3A and 3B are diagrams for explaining the external forces acting on the needle in FIG. 2 (when the outer diameter of the needle seal portion is approximately equal to the valve port diameter), in which (a) is an overall view of the needle, and (b) is a schematic diagram of the pressure acting on the needle seal portion and the valve portion shown in (a). 5A and 5B are diagrams showing secondary pressure-valve opening pressure characteristics having the influence of processing tolerances in a pressure regulating valve, in which FIG. 5A shows a conventional pressure regulating valve, and FIG. 5B shows the pressure regulating valve of the first embodiment. 1A and 1B are explanatory diagrams of external forces acting on a needle in a pressure regulating valve according to a modified example of the first embodiment (when the outer diameter of the needle seal portion is greater than the valve port diameter), in which (a) is an overall view of the needle, and (b) is a schematic diagram of pressures acting on the needle seal portion and the valve portion shown in (a). FIG. 6 is a characteristic diagram of secondary pressure vs. valve opening pressure in the pressure regulating valve shown in FIG. FIG. 11 is a cross-sectional view showing a pressure regulating valve according to a second embodiment in a valve closed state. FIG. 8 is a partial enlarged view of region VIII in FIG. 7 . FIG. 11 is a cross-sectional view showing a pressure regulating valve according to a third embodiment in a valve closed state. FIG. 10 is a partially enlarged view of a region X in FIG. 9 . 1A and 1B are cross-sectional views showing a conventional pressure regulating valve in a valve closed state, where FIG. 1A is an overall view, and FIG. 1B is a partially enlarged view of region XIb in FIG.

An embodiment of the present invention will be described in detail with reference to Figures 1 to 10. However, the present invention is not limited to this embodiment.

<Terminology>
In the present specification and claims, "upper" and "lower" refer to the "adjustment spring unit side" and "needle side". In the present specification and claims, "one end" and "other end" refer to the "needle side" and "adjustment spring unit side". In the present specification and claims, "effective pressure-receiving area of the pressure-sensing bellows" refers to the pressure-receiving area as an approximate value calculated based on the average inner diameter of the minimum inner diameter of the bellows shape (the inner diameter of the "valley" part of the bellows shape that protrudes toward the central axis of the pressure-sensing bellows) and the maximum inner diameter (the inner diameter of the "peak" part of the bellows shape that protrudes in a direction away from the central axis of the pressure-sensing bellows). In the present specification and claims, "guidable" refers to something that includes "slidable". In the present specification and claims, "convex-concave engagement" refers to engagement between a shape that is recessed in the axial direction and a shape that protrudes, respectively. In this specification and the claims, “the outer diameter of the needle seal portion and the valve port diameter are approximately the same” and “the outer diameter of the needle seal portion is slightly larger than the valve port diameter” mean “within the range of 0.8<X<1.2” and “within the range of 1<X<1.2”, where X is the ratio of the outer diameter of the needle seal portion to the valve port diameter.

(First embodiment)
<Configuration of the pressure regulating valve>
A pressure regulating valve 100A according to a first embodiment of the present invention will be described with reference to Figures 1 and 2. The pressure regulating valve 100A is mainly composed of a valve body 5, a needle (valve body) 30, a pressure sensitive unit 40, and an adjusting spring unit 50. Below, each component of the pressure regulating valve 100A will be described in order, along with a lower connecting means 60 and an upper connecting means 70. In the pressure regulating valve 100A, the needle 30, the pressure sensitive unit 40, and the adjusting spring unit 50 are assembled to the valve body 5 in this order, in a state in which they are indirectly engaged from one end side to the other end side.

As will be described in detail later, the pressure regulating valve 100A of this embodiment adjusts the pressure receiving area S4 of the needle seal portion 34 to be approximately the same as the pressure receiving area S2 of the valve portion 32 surrounded by the valve seat member 18, which is the flow rate standard, as shown in FIG. 3(b) (i.e., the outer diameter D4 of the needle seal portion 34 is approximately the same as the valve port diameter D2). As a result, the pressure regulating valve 100A of this embodiment can relatively easily suppress the influence of the secondary pressure P2, and can solve the conventional problem (changes in valve opening pressure due to secondary pressure).

First, the valve body 5 is composed of the joint connector 3, the valve seat member 18, the lower valve body 10 to which the joint connector 3 and the valve seat member 18 are fixed, the upper valve body 15 which is joined to the other end of the lower valve body 10 by brazing, welding, etc., and the spring case 20 which is joined to the other end of the upper valve body 15 by crimping, etc. This valve body 5 is composed of an appropriate material such as metals such as brass, iron, aluminum, stainless steel, etc., or resin materials such as polyphenylene sulfide (PPS).

The joint connector 3 has an inlet port 11a at one end that connects to the inlet pipe 1 (primary joint), and a circular recess 3a at the other end.

In this embodiment, the joint connector 3 and the lower valve body 10 are separate components, and the communication recess 3a is formed in the joint connector 3 by simple machining, eliminating the need for slotting to serve as a pressure introduction path to the lower valve body 10, as described below, which was previously required, shortening the processing time and allowing the formed communication recess 3a to be easily seen.

In this embodiment, the communication recess 3a of the joint connector 3 is a circular recess, but the shape may be any shape that communicates between the inlet port 11a and the pressure equalizing path 10a, such as a linear recess. In this embodiment, the communication recess 3a that communicates between the inlet port 11a and the pressure equalizing path 10a is provided in the joint connector 3, but the shape may be any shape that communicates between the inlet port 11a and the pressure equalizing path 10a. In addition, the communication recess 3a of the joint connector 3 may be replaced by a communication recess 10d (see FIG. 8) that is circularly recessed on one end of the lower valve body 10, or the communication recess 3a and the communication recess 10d may be formed in each of the joint connector 3 and the lower valve body 10.

The valve seat member 18 has a valve port 12 penetrating through it, and an annular valve seat 18a is provided at the connection between the valve chamber 13 and the valve port 12.

The lower valve body 10 has a through hole along the central axis C, and a plurality of annular steps are formed in the through hole, which are gradually enlarged in diameter from the other end side to the one end side along the central axis C. The needle guide hole 14 and the valve chamber 13 are defined in the plurality of annular steps from the other end side to the one end side, and the valve seat member 18 and the coupling connector 3 are fixed to the continuous annular step on the one end side by insertion and brazing, respectively. In addition, the lower valve body 10 has a seal housing groove 10c on the other end side of the needle guide hole 14, which has an inner diameter set larger than that of the needle guide hole 14. In addition, the lower valve body 10 has a cylindrical spring housing groove 10b on the outer periphery of the through hole on the other end side, which supports one end side of the valve spring 6 and houses the valve spring 6, and a pressure equalizing path 10a (pressure introduction path) which communicates with the spring housing groove 10b and extends along a direction parallel to the central axis C. In addition, the lower valve body 10 has a through hole that penetrates radially from the valve chamber 13, and this through hole is provided with an outlet port 11b that connects to the outflow pipe 2.

In this embodiment, the valve seat member 18 and the lower valve body 10 are separate, which eliminates the need for boring into the relatively deep valve chamber 13 and makes it easier to access the outlet port 11b of the lower valve body 10, improving the efficiency of burr removal.

The upper valve body 15 is made of a hollow cylindrical member and has a back pressure chamber 17 along the central axis C that houses the pressure sensing unit 40.

The lower valve body 10 and the upper valve body 15 have two pressure introduction paths that introduce the primary pressure P1 and the secondary pressure P2, respectively, when the valve is closed.

First, the first pressure introduction path introduces the primary pressure P1 from the inlet port 11a to the back pressure chamber 17 when the valve is closed, and communicates via the communication recess 3a, the pressure equalization path 10a, and the spring housing groove 10b. The back pressure chamber 17 to which the primary pressure P1 is introduced communicates with the seal housing groove 10c. In addition, the valve spring 6 is interposed in the first pressure introduction path, but is positioned so as not to completely block the flow path, so that the primary pressure P1 can be reliably introduced into the back pressure chamber 17.

The second pressure introduction path introduces the secondary pressure P2 from the outlet port 11b to the seal housing groove 10c when the valve is closed, and communicates with the valve chamber 13 via the gap formed between the needle guide hole 14 and the needle guide portion 31.

The other end of these two pressure introduction paths is partitioned by the seal member 7 placed in the seal housing groove 10c so that they are always in a non-communicating state. As a result, when the valve is in a closed state, the primary side pressure P1 can be introduced into the back pressure chamber 17 via the inlet port 11a, and the secondary side pressure P2 can be introduced into the seal housing groove 10c located on one end side of the seal member 7 via the outlet port 11b.

In this embodiment, the pressure equalization passage 10a, which serves as the pressure introduction passage, is formed in the lower valve body 10, and since there is no need to provide a pressure introduction passage in the needle 30 as in the conventional pressure regulating valve 1100 shown in FIG. 11(a), the diameter of the needle 30 and the valve port 12 can be made thinner. As a result, the pressure regulating valve 100A can be made smaller and adapted to small flow rates, and the shape of the needle 30 can also be simplified.

The spring case 20 is a hollow cylindrical member having a through hole that runs along the central axis C, and is provided with a spring accommodating chamber 21. A female threaded portion 22 is provided on the inner periphery of the other end of the spring case 20, and is screwed with a male threaded portion 52a provided on the outer periphery of the adjustment screw member 52 so as to be movable in the axial direction. Atmosphere is constantly introduced into the spring accommodating chamber 21 via this screwed portion.

Next, the needle 30 will be described. The needle 30 is made of a metal such as stainless steel, and includes a valve portion 32 having a generally truncated cone shape provided at one end, a spring support portion 33 made of a thin plate of stainless steel provided at the other end, a cylindrical needle guide portion 31 provided between the valve portion 32 and the spring support portion 33, and a needle seal portion 34 provided at a position facing the seal housing groove 10c. This needle seal portion 34 reduces the diameter of a part of the needle 30, and the outer diameter D4 (see FIG. 3(a)) of the needle seal portion 34 is set smaller than the outer diameter D3 (see FIG. 3(a)) of the needle guide portion 31. Here, a ring-shaped seal member 7 (e.g., an O-ring) having a radial thickness slightly larger than this gap is disposed in the gap between the needle seal portion 34 and the seal housing groove 10c. As a result, the inner and outer circumferential surfaces of the seal member 7 are always in contact with the needle seal portion 34 and the seal housing groove 10c, respectively, so the valve chamber 13 and the back pressure chamber 17 can be partitioned in a non-communicating state. In addition, because the seal member 7 is made of a material with low friction (such as fluororubber), the frictional resistance of the needle 30 against the seal member 7 can be made extremely small.

In this embodiment, the means for holding the seal member 7 is a seal housing groove 10c that houses the seal member 7 in the lower valve body 10, but is not limited to this. For example, the needle 30 may be provided with a seal housing groove that houses the seal member 7, or both the lower valve body 10 and the needle 30 may be provided with seal housing grooves that house the seal member 7.

The needle guide portion 31 is arranged so as to be guided in the axial direction within the needle guide hole 14 of the lower valve body 10. Here, the gap formed between the outer diameter D3 of the needle guide portion 31 and the inner diameter of the needle guide hole 14 is set to be relatively small, and strict processing tolerances are managed. In addition, the needle 30 is constantly biased in the valve opening direction by the valve spring 6 sandwiched between the spring support portion 33 of the needle 30 and the bottom surface of the spring accommodation groove 10b of the lower valve body 10. In this way, the needle 30 is guided in a stable axial direction, and the central positions of the needle 30 and the valve seat 18a as viewed from the direction of the central axis C always coincide, so that the flow rate can be stabilized and the valve leakage can be improved.

The axial movement of the needle 30 is caused by the pressure difference between the primary pressure P1 and the secondary pressure P2, the biasing force of the pressure-sensitive bellows 41 and the adjustment spring 53 acting on the other end of the valve portion 32, and the biasing force of the valve spring 6 acting on the spring support portion 33, as described in detail below. These external forces cause the valve portion 32 to move toward and away from the valve seat 18a, and the valve opening degree is determined. Here, the step portion 45c of the connecting rod 45 abuts against the bellows top cover 43, thereby defining the maximum valve lift amount from the valve closed state of the needle 30 to the valve fully open state, which is the maximum valve lift state. In addition to the valve fully open state, which is the maximum valve lift state, in the pressure regulating valve 100A of this embodiment, there is a valve fully open state in which a specified flow rate flows before the step portion 45c of the connecting rod 45 abuts against the bellows top cover 43.

Next, the pressure-sensing unit 40 will be described. The pressure-sensing unit 40 is composed of a pressure-sensing bellows (pressure-sensing member) 41, a bellows top cover 43, and a connecting rod 45 having one end and the other end extending along the central axis C. The pressure-sensing bellows 41 has one end and the other end extending along the central axis C connected to one end of the connecting rod 45 and the bellows top cover 43, respectively, and biases the valve portion 32 in the valve closing direction. The pressure-sensing unit 40 is made of a metal such as stainless steel, and is housed in the back pressure chamber 17 of the upper valve body 15. In this embodiment, the pressure-sensing bellows 41 is incorporated into the back pressure chamber 17 in a state in which it is contracted relative to its free length, and the pressure-sensing bellows 41 biases the valve portion 32 in the valve closing direction. However, this is not limiting, and the pressure-sensing bellows 41 may be inserted into the back pressure chamber 17 in a state in which the pressure-sensing bellows 41 is stretched relative to its free length, so that the pressure-sensing bellows 41 biases the valve portion 32 in the valve opening direction.

The pressure-sensing bellows 41 is connected to one end of the connecting rod 45 and the bellows top cover 43, so that the primary pressure P1 is constantly introduced into the external space of the pressure-sensing bellows 41 through the inlet port 11a, the communicating recess 3a, the pressure equalizing passage 10a, the spring accommodation groove 10b, and the back pressure chamber 17. On the other hand, the atmosphere is constantly introduced into the internal space of the pressure-sensing bellows 41 through the gap formed between the small diameter portion 45b of the connecting rod 45 and the insertion hole 43a of the bellows top cover 43, and the gap formed between the upper ball 73 and the sliding portion 43c of the bellows top cover 43. In addition, the dimensional relationship of each part is set so that the outer diameter of the peaks and the inner diameter of the valleys of the bellows shape are always in a non-contact state with the upper valve body 15 and the connecting rod 45.

The connecting rod 45 has a generally cylindrical large diameter portion 45a extending toward one end in the axial direction, and a generally cylindrical small diameter portion 45b extending from the large diameter portion 45a toward the other end in the axial direction. One end of the large diameter portion 45a is formed with a flange portion 45d that protrudes in the radial direction and to which one end of the pressure-sensing bellows 41 is connected. In addition, an annular step portion 45c is formed between the large diameter portion 45a and the small diameter portion 45b.

The bellows top cover 43 extends concentrically along the central axis C and includes an insertion hole 43a through which the small diameter portion 45b of the connecting rod 45 passes, a bellows top cover joint 43b to which the other end of the pressure-sensing bellows 41 is connected, and a cylindrical sliding portion 43c that extends concentrically along the central axis C and has an inner diameter larger than that of the insertion hole 43a, through which the small diameter portion 45b of the connecting rod 45 passes and through which the upper ball 73 slides. Here, the pressure-sensing unit 40 is fixed to the valve body 5 via a welded portion w so that it cannot be displaced relative to the valve body 5. This welded portion w indicates the area where the other ends of the bellows top cover 43 and the upper valve body 15 are welded to each other. By adjusting the axial position of this welded portion w, individual differences in the length of the pressure-sensing unit 40 and assembly errors to the valve body 5 can be absorbed.

In this embodiment, one end of the pressure-sensing unit 40 is configured to connect the pressure-sensing bellows 41 and the flange portion 45d of the connecting rod 45, but this is not limited to the above. For example, a pressure-sensing bellows 41 having a capped lower end or a bellows lower cover in which the flange portion 45d is separated from one end of the connecting rod 45 may be used, and the flange portion 45d may be omitted from the connecting rod 45, with one end of the connecting rod 45 being connected to the capped lower end or the bellows lower cover. By connecting one end of the connecting rod 45 in a manner that allows it to move radially relative to the capped lower end or the bellows lower cover, it is possible to absorb the inclination of the connecting rod 45 with respect to the central axis C and the asymmetry of the pressure-sensing bellows 41.

In this embodiment, the other end side of the pressure sensing unit 40 is configured by connecting the pressure sensing bellows 41 and the bellows top cover 43, but this is not limited to the above. For example, a pressure sensing bellows 41 having a flange-shaped upper end may be used, the bellows top cover 43 may be omitted, and the outer edge of the upper end of the pressure sensing bellows 41 may be fixed to the inner wall of the upper valve body 15, which is the valve body 5, so that it cannot be displaced relative to the pressure sensing bellows 41, and the upper valve body 15 may be used as the bellows top cover 43. In this way, when the upper end of the pressure sensing bellows 41 is fixed to the inner wall of the upper valve body 15, the insertion hole 43a and the sliding portion 43c of the bellows top cover 43 are formed in the inner wall of the upper valve body 15.

The lower connection means 60 will now be described. The lower connection means 60 is composed of a pair of recesses 61, 62 formed on the axially opposing surfaces of the needle 30 and the pressure-sensing unit 40, and a lower ball 63 that is sandwiched between the pair of recesses 61, 62 to form a concave-convex engagement. The pair of recesses 61, 62 are formed at the axial center of the upper end surface of the needle 30 and the lower end surface of the large diameter portion 45a, and are composed of a conical lower recess 61 and upper recess 62. The conical shape has a bottom surface formed concentrically with the central axis C, and an apex located on the central axis C. The lower ball 63 is composed of a metal such as stainless steel.

As a result, the needle 30 is arranged in the needle guide hole 14 of the lower valve body 10 so as to be guided along the central axis C, and the center position of the lower recess 61 is always located on the central axis C. In addition, the center position of the upper recess 62 is independently located on the central axis C because a centripetal force acts on the upper recess 62 via the lower recess 61 and the lower ball 63. This makes it possible to suppress the transmission of a biasing force that is not along the central axis C, due to the asymmetry of the pressure-sensing bellows 41, to the needle 30, thereby reducing the sliding resistance of the needle 30. In this embodiment, the lower recess 61 and the upper recess 62 each have a conical shape, but are not limited to this and may have a spherical shape, for example.

In addition, the adjustment spring unit 50 will be described. The adjustment spring unit 50 is composed of a spring receiving member 51, an adjustment screw member 52, and an adjustment spring 53 that is sandwiched between the spring receiving member 51 and the adjustment screw member 52 and biases the valve portion 32 in the valve closing direction. The spring receiving member 51 and the adjustment screw member 52 are made of appropriate materials such as metals such as brass, iron, aluminum, and stainless steel, and resin materials such as polyphenylene sulfide (PPS), and are housed in the spring housing chamber 21 of the spring case 20. By screwing the male threaded portion 52a provided on the outer periphery of the adjustment screw member 52 with the female threaded portion 22 provided on the inner periphery of the other end of the spring case 20, and moving the adjustment screw member 52 in the axial direction, the biasing force of the adjustment spring 53 can be adjusted, and the pressure (set value) at which the needle 30 opens the valve can be adjusted.

The adjustment spring 53 is a multi-wound wave spring (hereinafter referred to as a "wave spring") made of a metal such as stainless steel. This wave spring is made by bending a wire rod with a rectangular cross section into a sinusoidal waveform at a specified pitch, and contact and separation parts that bring the peaks and valleys facing each other in the direction of the spring's central axis into contact with and separate from each other are formed alternately in the winding direction, resulting in a cylindrical shape overall. Therefore, when the wave spring is compressed, the multiple contact parts always serve as fulcrums, suppressing side forces and ensuring the transmission of biasing force along the central axis C.

Finally, the upper connection means 70 will be described. The upper connection means 70 is composed of a pair of engagement parts 71, 72 formed on the axially opposing surfaces of the connecting rod 45 and the spring receiving member 51, and a spherical upper ball 73 that is sandwiched between the pair of engagement parts 71, 72 to form a concave-convex engagement. The pair of engagement parts 71, 72 are formed on the axial center of the upper end surface of the small diameter part 45b and the lower end surface of the spring receiving member 51, and are composed of a conical lower engagement part 71 and an upper engagement part 72. This conical shape has a bottom surface formed concentrically with the central axis C, and an apex located on the central axis C. The upper ball 73 is also composed of a metal such as stainless steel.

Here, as viewed from the direction of the central axis C, the radius of the circular side of the upper ball 73 is set slightly smaller than the radius of the sliding part 43c, so that an extremely narrow gap is formed between the side of the upper ball 73 and the sliding part 43c. Therefore, the side of the upper ball 73 is always in point contact with the sliding part 43c, and the radial movement is restricted, so that the center position of the upper ball 73 is always located near the central axis C. In addition, the center positions of the lower engaging part 71 and the upper engaging part 72 are independently located near the central axis C because a centripetal force acts on the lower engaging part 71 and the upper engaging part 72 via the upper ball 73, whose radial movement is restricted. Furthermore, the small diameter part 45b of the connecting rod 45 is set to be inserted along the central axis C in a non-contact state with the insertion hole 43a. In this way, the upper connection means 70 prevents the connecting rod 45 from tilting relative to the central axis C, and reduces the sliding resistance with the sliding part 43c, thereby reducing hysteresis.

<Operation of the pressure regulating valve>
The operation of the pressure regulating valve 100A will be described. Here, the pressure regulating valve 100A is described as being used in a refrigerant circuit, but is not limited to this. In the pressure regulating valve 100A, the inlet port 11a is connected to an inlet pipe 1 on the high pressure (primary pressure P1) side, and the outlet port 11b is connected to an outlet pipe 2 on the low pressure (secondary pressure P2) side.

(When the primary pressure P1 is lower than the set value (valve opening pressure))
When the primary pressure P1 is lower than the set value (for example, when the discharge pressure of the compressor is reduced), the valve portion 32 is seated on the valve seat 18a and the valve is closed as shown in Fig. 2. At that time, the primary pressure P1 is introduced into the external space of the pressure-sensing bellows 41, which is the back pressure chamber 17, via the inlet port 11a, the communication recess 3a, the pressure equalizing passage 10a, and the spring accommodating groove 10b.

First, the pressure-sensing bellows 41 generates a force acting in the direction in which the valve portion 32 opens, which is the primary pressure P1 x effective pressure-receiving area S1 (see FIG. 2). Here, the effective pressure-receiving area S1 of the pressure-sensing bellows 41 is the pressure-receiving area calculated based on the average inner diameter of the minimum and maximum inner diameters of the bellows shape.

Next, the needle 30 is subjected to the pressure forces acting in the direction of opening the valve portion 32: primary side pressure P1 x pressure receiving area S2 (see FIG. 3(b)) and secondary side pressure P2 x pressure receiving area (S3-S2) (see FIG. 3(b)). On the other hand, the needle 30 is subjected to the pressure forces acting in the direction of closing the valve portion 32: primary side pressure P1 x pressure receiving area S4 (see FIG. 3(b)) and secondary side pressure P2 x pressure receiving area (S3-S4) (see FIG. 3(b)). Furthermore, the needle 30 is subjected to the biasing force F1 of the pressure-sensing bellows 41 and the biasing force F2 of the adjustment spring 53 as forces acting in the direction of closing the valve portion 32. In addition, the needle 30 is subjected to the biasing force of the valve spring 6 as a force acting in the direction of opening the valve portion 32. The biasing force of the valve spring 6 is only sufficient to counteract the weight of the needle 30, so it is not included in the following formula (1). Also, the seal member 7 is made of a low-friction material and has extremely low frictional resistance to the needle 30, so it is not included in the following formula (1).

Therefore, the balance of the external forces acting on the needle 30 of the pressure regulating valve 100A can be expressed as follows: The left side is the force in the direction that opens the valve, and the right side is the force in the direction that closes the valve.
P1×S1+P1×S2+P2×(S3-S2)=P1×S4+P2×(S3-S4)+F1+F2 (Formula 1)
Where, P1: primary pressure [N/mm ² ]
P2: Secondary pressure [N/mm ² ]
S1: Effective pressure-receiving area of the pressure-sensing bellows 41 [mm ² ]
S2: Pressure-receiving area of the valve portion 32 surrounded by the valve seat 18a [mm ² ]
S3: Pressure-receiving area of the needle guide portion 31 [mm ² ]
S4: Pressure-receiving area of the needle seal portion 34 [mm ² ]

F1: biasing force by pressure-sensing bellows 41 [N]
F2: biasing force of the adjustment spring 53 [N]

Equation 1 can be rearranged as follows:
P1×S1=(S4-S2)×(P1-P2)+F1+F2 (Formula 2)
P1×(S1+S2-S4)=P2×(S2-S4)+F1+F2 (Formula 3)
P1=P2×(S2-S4)/(S1+S2-S4)+(F1+F2)/(S1+S2-S4) (Formula 4)

Ideally, the effective pressure-receiving area S4 of the needle seal portion 34 is set to match the pressure-receiving area S2 of the valve portion 32 surrounded by the valve seat 18a (S2 = S4).

Therefore, (Equation 4) can be further rearranged as follows:
P1=(F1+F2)/S1 (Formula 5)

As shown in (Equation 5), the effect of the secondary pressure P2 can be cancelled out by matching the pressure-receiving area S2 of the valve portion 32 surrounded by the valve seat 18a and the effective pressure-receiving area S4 of the needle seal portion 34.

(When the primary pressure P1 is higher than the set value (valve opening pressure))
When the primary side pressure P1 is higher than the set value ((F1+F2)/S1) (for example, when the discharge pressure of the compressor increases), the valve portion 32 is separated from the valve seat 18a (not shown) and the valve is in an open state. At this time, the valve opening degree increases with an increase in the primary side pressure P1. Here, the pressure regulating valve 100A of this embodiment can obtain a large valve lift amount by using a pressure-sensing bellows 41 as the pressure-sensing member.

2, the effective pressure-receiving area S1 of the pressure-sensing bellows 41 is π/4× ^D1² , where D1 indicates the average inner diameter of the pressure-sensing bellows 41. Furthermore, the pressure-receiving areas S2, S3, and S4 of the needle 30 are π/4× ^D2² , π/4×D3², and π/4×D4², respectively, as shown in Figures ³ (a) and 3(b ⁾ , where D2 indicates the valve port diameter, D3 indicates the outer diameter of the needle guide portion 31, and D4 indicates the outer diameter of the needle seal portion 34.

<Secondary pressure - valve opening pressure characteristics affected by machining tolerance>
From here, the secondary pressure P2-valve opening pressure Pop characteristics influenced by processing tolerances will be described for the conventional pressure regulating valve 1100 and the pressure regulating valve 100A of this embodiment, in that order, with reference to Figures 11, 3, and 4. In Figures 4(a) and 4(b), "a" represents the influence of the processing tolerances of the valve port diameters D2 and D2', "b" represents the influence of the processing tolerances of the average inner diameter D1' of the pressure-sensing bellows 1141, and "c" represents the influence of the processing tolerances of the outer diameter D4 of the needle seal portion 34. In addition, the secondary pressure-valve opening pressure characteristics in Figures 4(a) and 4(b) are shown with the influence of the processing tolerances exaggerated for the sake of explanation.

First, as described above, in the conventional pressure regulating valve 1100, in order to cancel the effect of the secondary pressure P2 acting on the pressure-sensing bellows 1141 and the valve portion 1132, as shown in FIG. 11(b), the effective pressure-receiving area S1' of the pressure-sensing bellows 1141 is made to match the pressure-receiving area S2' of the valve portion 1132 surrounded by the valve seat 1118, that is, the average inner diameter D1' of the pressure-sensing bellows 1141 is made to match the valve port diameter D2' of the valve housing 1110. However, the conventional pressure regulating valve 1100 has a conventional problem (changes in valve opening pressure due to secondary pressure) because the variation in the machining tolerances of the pressure-sensing bellows 1141 in particular is relatively large.

For this reason, as shown in FIG. 4(a), the secondary pressure P2-valve opening pressure Pop characteristic in the conventional pressure regulating valve 1100 (hereinafter referred to as the "conventional secondary pressure P2-valve opening pressure Pop characteristic") is influenced by an influence a due to the machining tolerance of the valve port diameter D2' and an influence b due to the machining tolerance of the average inner diameter D1' of the pressure-sensitive bellows 1141. Here, in contrast to the cutting process for the valve port diameter D2', the pressure-sensitive bellows 1141 is formed by a molding method in which the variation in machining tolerance is relatively large, so the machining tolerance of the pressure-sensitive bellows 1141 is several tens of times larger than the machining tolerance of the valve port diameter D2'.

As a result, the conventional secondary pressure P2-valve opening pressure Pop characteristic is dominated by the effect b of the processing tolerance of the pressure-sensing bellows 1141, and from the set valve opening pressure Psop at secondary pressure P2 = 0, there is a relatively large increase (dashed line in the figure) or decrease (solid line) as the secondary pressure P2 increases. For this reason, in the conventional pressure regulating valve 1100, the secondary pressure P2-valve opening pressure Pop characteristic has a large variation compared to the ideal (desired) valve opening pressure characteristic (constant pressure Pop), and individual differences are relatively large.

In contrast, in the pressure regulating valve 100A of this embodiment, since the machining tolerance is taken into consideration, the effect of the secondary pressure P2 acting on each of the needle seal portion 34 and the valve portion 32 cannot be completely canceled, but the effect of the secondary pressure P2 is reliably suppressed. In the pressure regulating valve 100A of this embodiment, as shown in FIG. 3(b), the pressure receiving area S4 of the needle seal portion 34 and the pressure receiving area S2 of the valve portion 32 surrounded by the valve seat 18a are made substantially the same, that is, the outer diameter D4 of the needle seal portion 34 and the valve port diameter D2 are made substantially the same. In this embodiment, "the outer diameter D4 of the needle seal portion 34 and the valve port diameter D2 are substantially the same" specifically means that, when the ratio of the outer diameter D4 of the needle seal portion 34 to the valve port diameter D2 is X, "the ratio is within the range of 0.8<X<1.2." In addition, the equation for balancing the external forces acting on the needle 30 in the pressure regulating valve 100A of this embodiment is (Equation 4).

As a result, as shown in FIG. 4(b), the secondary pressure P2-valve opening pressure Pop characteristic in the pressure regulating valve 100A of this embodiment (hereinafter referred to as the "secondary pressure P2-valve opening pressure Pop characteristic of this embodiment") is influenced by the effect a due to the machining tolerance of the valve port diameter D2 and the effect c due to the machining tolerance of the outer diameter D4 of the needle seal portion 34. Here, the machining tolerance of the outer diameter D4 of the needle seal portion 34 is the same as the machining tolerance of the valve port diameter D2, and is machined (e.g., cut), so it can be made extremely small compared to the machining tolerance in a molding method in which the variation in the machining tolerance of the average inner diameter D1' of the conventional pressure-sensitive bellows 1141 is relatively large.

For this reason, the secondary pressure P2-valve opening pressure Pop characteristic of this embodiment starts from the set valve opening pressure Psop when the secondary pressure P2 = 0, and as the secondary pressure P2 increases, the valve opening pressure Pop increases slightly (dashed line in the figure) or decreases (solid line). As a result, with the pressure regulating valve 100A of this embodiment, the variation in the secondary pressure P2-valve opening pressure Pop characteristic, that is, the individual differences, can be made extremely small compared to the conventional pressure regulating valve 1100.

In the pressure regulating valve 100A of this embodiment, the outer diameter D4 of the needle seal portion 34 and the valve port diameter D2 are made substantially the same, and the pressure acting on the pressure-sensing bellows 41, which is the main force in the valve opening direction on the left side of (Equation 1), is changed from the secondary pressure P2 of the conventional pressure regulating valve 1100 to the primary pressure P1 of the pressure regulating valve 100A of this embodiment, thereby eliminating the conventional problem (changes in valve opening pressure due to secondary pressure). In addition, in this embodiment, the pressure equalizing passage 10a, which serves as the pressure introduction passage, is formed in the lower valve body 10, and there is no need to provide a pressure introduction passage in the needle 30, so the needle 30 and the valve port 12 can be made thinner, and as a result, the pressure regulating valve 100A can be made smaller and adapted to small flow rates.

(Modification of the first embodiment)
A pressure regulating valve 100A' according to a modification of the first embodiment will be described with reference to Figures 5 and 6. The pressure regulating valve 100A' according to the modification of the first embodiment differs from the pressure regulating valve 100A of the first embodiment in that the outer diameter D4' of the needle seal portion 34' is set slightly larger than the valve port diameter D2 and is the same as the outer diameter D3 of the needle guide portion 31. However, the other basic configuration is the same as that of the first embodiment. Here, the same members are given the same reference numerals, and duplicated explanations will be omitted.

<Regarding the new issue (increase in valve opening pressure due to secondary pressure)>
As shown in FIG. 4(b), the pressure regulating valve 100A in the first embodiment is configured such that, taking into consideration processing tolerances, the outer diameter D4 of the needle seal portion 34 and the valve port diameter D2 are made substantially the same, thereby extremely reducing the variation in the secondary pressure P2-valve opening pressure Pop characteristics and eliminating the conventional problem (changes in valve opening pressure due to secondary pressure).

Here, since the pressure regulating valve 100A in the first embodiment is arranged in, for example, a refrigerant circuit, it is required that the valve opening pressure Pop is set to Psop (desired primary pressure P1) regardless of the secondary pressure P2, and the valve starts to open. In the strength design of this refrigerant circuit, the fluid equipment and piping connected to the refrigerant circuit are selected based on the maximum allowable pressure Pa of the refrigerant circuit plus a predetermined margin α (hereinafter referred to as "maximum allowable pressure (including margin)") (Pa + α). Here, the set valve opening pressure Psop in the pressure regulating valve 100A is naturally set to be lower than the maximum allowable pressure Pa (set valve opening pressure Psop < maximum allowable pressure Pa < maximum allowable pressure (including margin) (Pa + α)).

First, if the valve opening pressure Pop decreases as the secondary pressure P2 increases, as shown by the solid line in Figure 4(b), there is no problem because the valve opening pressure Pop does not exceed the maximum allowable pressure Pa.

On the other hand, as shown by the dashed line in FIG. 4(b) in the secondary pressure P2-valve opening pressure Pop characteristic, if the valve opening pressure Pop increases as the secondary pressure P2 increases, the valve opening pressure Pop may exceed the maximum allowable pressure (including margin) (Pa+α), and in particular, there is a risk of damage to the fluid equipment and piping (hereinafter referred to as "primary fluid equipment") fluidly connected to the primary side of the pressure regulating valve 100A (hereinafter referred to as "new problem (increase in valve opening pressure due to secondary pressure)"). In response to this, it is possible to increase the specified margin α when selecting the primary fluid equipment, but since this may lead to an increase in the cost of the primary fluid equipment, it is desirable to keep the specified margin α as small as possible.

In contrast, in the pressure regulating valve 100A' according to the modified example of the first embodiment, as shown in FIG. 5, in order to solve the new problem described above (increase in valve opening pressure due to secondary pressure), the pressure receiving area S4' of the needle seal portion 34' is set slightly larger than the pressure receiving area S2 of the valve portion 32 surrounded by the valve seat 18a, i.e., the outer diameter D4' of the needle seal portion 34' is set slightly larger than the valve port diameter D2.

<Specific means for setting dimensions (D4'>D2)>
Here, the outer diameter D4' of the needle seal portion 34' and the valve port diameter D2 are values that have a machining tolerance. Therefore, as a specific dimension setting means (D4'>D2), the difference between the target values of the outer diameter D4' of the needle seal portion 34' and the valve port diameter D2 is set in advance to be larger than the machining tolerance. For example, by setting the target values of the outer diameter D4' of the needle seal portion 34' and the valve port diameter D2 to 3.5 mm and 3 mm, respectively, and performing machining such as cutting, it is possible to reliably set the outer diameter D4' of the needle seal portion 34' to be slightly larger than the valve port diameter D2 even if the outer diameter D4' of the needle seal portion 34' and the valve port diameter D2 have a machining tolerance of, for example, about ±0.01 mm. In this embodiment, "the outer diameter D4' of the needle seal portion 34' is slightly larger than the valve port diameter D2" specifically means that, when the ratio of the outer diameter D4' of the needle seal portion 34' to the valve port diameter D2 is X, "it is within the range of 1 < X <1.2."

<Secondary pressure - valve opening pressure characteristics>
The secondary side pressure P2-valve opening pressure Pop characteristic of the pressure regulating valve 100A' according to a modified example of the first embodiment shown in Figure 6 (hereinafter referred to as the "secondary side pressure P2-valve opening pressure Pop characteristic of the modified example") is obtained by replacing S4 in (Equation 4) with S4', that is, is based on the following (Equation 6).
P1=P2×(S2-S4')/(S1+S2-S4')+(F1+F2)/(S1+S2-S4') (Formula 6)

In this (Equation 6), the secondary pressure P2 on the right-hand side has a slope of (S2-S4')/(S1+S2-S4'). Since the denominator of this slope (S1+S2-S4') is always set to be positive, the sign of the numerator of the slope (S2-S4') determines whether the secondary pressure P2-valve opening pressure Pop characteristic of the modified example has a positive or negative slope.

As shown in FIG. 6, although it is different from the pressure regulating valve 100A' according to the modified example, if the pressure receiving area S4'' of the needle seal portion 34' is set smaller than the pressure receiving area S2 of the valve portion 32 surrounded by the valve seat 18a (outer diameter D4'' of the needle seal portion 34' < valve port diameter D2), the slope of the secondary pressure P2 is always positive, resulting in the secondary pressure P2 - valve opening pressure Pop characteristic shown by the dashed line in FIG. 6.

On the other hand, when the pressure receiving area S4' of the needle seal portion 34' is set slightly larger than the pressure receiving area S2 of the valve portion 32 surrounded by the valve seat 18a (outer diameter D4' of the needle seal portion 34' > valve port diameter D2), as in the pressure regulating valve 100A' according to the modified example, the slope of the secondary pressure P2 is always negative, resulting in the secondary pressure P2 - valve opening pressure Pop characteristic shown by the solid line in Figure 6.

As described above, the pressure regulating valve 100A' according to the modified example of the first embodiment can achieve the same effect as the first embodiment, that is, it can eliminate the conventional problem (changes in valve opening pressure due to secondary pressure). In addition, in the modified example of the first embodiment, the outer diameter D4' of the needle seal portion 34' is set slightly larger than the valve port diameter D2, which eliminates a new problem (increase in valve opening pressure due to secondary pressure) and ensures that the valve begins to open at or below the set valve opening pressure Psop (desired primary pressure P1), so that the pressure regulating valve 100A' can be used as a safety valve or a liquid seal prevention valve.

Second Embodiment
Here, a pressure regulating valve 100B in a second embodiment will be described with reference to Figures 7 and 8. The pressure regulating valve 100B in the second embodiment differs from the pressure regulating valve 100A in the first embodiment mainly in that a thin tube 4, which is a separate member, is used instead of the pressure equalizing path 10a formed in the lower valve body 10, but the other basic configurations are the same as those of the first embodiment. Here, the same members are given the same reference numerals and duplicated explanations will be omitted.

<About the pressure introduction path to the back pressure chamber>
In the second embodiment, the pressure introduction path from the inlet port 11a to the back pressure chamber 17 communicates via the communication recess 10d, the first communication hole 10e, the thin tube 4, the second communication hole 10f, and the spring accommodating groove 10b.

The communication recess 10d is formed in the lower valve body 10' and consists of a circular recess formed between the annular steps into which the valve seat member 18 and the coupling connector 3' are inserted.

In this embodiment, the coupling connector 3 and the lower valve body 10' are separate components, and the communication recess 10d is formed in the lower valve body 10' by simple machining, which eliminates the need for slotting as a pressure introduction path to the lower valve body, shortening the processing time, and making the formed communication recess 10d easily visible.

The first communication hole 10e and the second communication hole 10f communicate from the side wall of the lower valve body 10' to the communication recess 10d and the spring accommodating groove 10b, respectively, and their openings to the outside are formed to be slightly enlarged in diameter.

The thin tube 4 is made of a tube material processed into a C-shape, and both ends are fixed to the openings of the first communication hole 10e and the second communication hole 10f by brazing or the like.

In this embodiment, the communication recess 10d of the lower valve body 10 is a circular recess, but is not limited thereto, and may be any shape that communicates the inlet port 11a and the thin tube 4 with each other, such as a linear recess. In this embodiment, the communication recess 10d that communicates the inlet port 11a and the thin tube 4 is provided in the lower valve body 10, but is not limited thereto, and for example, instead of the communication recess 10d of the lower valve body 10, the communication recess 3a (see FIG. 2) may be formed in the joint connector 3, or the communication recess 3a and the communication recess 10d may be formed in each of the joint connector 3 and the lower valve body 10. Furthermore, in this embodiment, the thin tube 4 is provided on the side opposite to the side on which the outflow tube 2 is provided, with respect to the central axis C, but is not limited thereto, and may be provided in any position as long as it does not interfere with the outflow tube 2.

As described above, the pressure regulating valve 100B in the second embodiment has the same effect as the first embodiment, that is, it can eliminate the conventional problem (changes in valve opening pressure due to secondary pressure). In addition, in the second embodiment, the thin tube 4 that serves as the pressure introduction path is a separate member from the lower valve body 10, so the processing cost for the lower valve body 10 can be reduced, and since there is no need to provide a pressure introduction path in the lower valve body 10 and the needle 30, the diameters of the lower valve body 10, the needle 30, and the valve port 12 can be reduced, and as a result, the pressure regulating valve 100B can be made smaller and can accommodate small flow rates.

In the pressure regulating valve 100B of the second embodiment, as in the modified example of the first embodiment, the outer diameter D4' of the needle seal portion 34' can be set slightly larger than the valve port diameter D2 to resolve the new issue (increase in valve opening pressure due to secondary pressure).

Third Embodiment
Here, a pressure regulating valve 100C according to a third embodiment will be described with reference to Figures 9 and 10. The pressure regulating valve 100C according to the third embodiment differs from the pressure regulating valve 100A according to the first embodiment in that a joint portion 1a' that expands in diameter is provided on the primary side joint 1' instead of the joint connector 3, but the other basic configurations are the same as those of the first embodiment. Here, the same members are given the same reference numerals, and duplicated explanations will be omitted.

<About the pressure introduction path to the back pressure chamber>
In the third embodiment, the pressure introduction passage from the inlet port 11a to the back pressure chamber 17 communicates via the inlet pipe line 1c', the pressure equalizing passage 10a, and the spring accommodating groove 10b.

The inlet pipe 1c' is formed in the inlet pipe 1'. This inlet pipe 1' has a base 1b' and a joint 1a' having an inner diameter larger than the inner diameter of the base 1b'. This joint 1a' is provided on one end side of the lower valve body 10 and is fixed by insertion, brazing, or the like into an annular step having an inner diameter slightly larger than the outer diameter of the joint 1a'. The inner diameter of the joint 1a' is set so that the inlet pipe 1c' and the pressure equalizing path 10a of the joint 1a' overlap each other when the joint 1a' is viewed from the direction of the central axis C.

As described above, the pressure regulating valve 100C in the third embodiment has the same effect as the first embodiment, that is, it can eliminate the conventional problem (change in valve opening pressure due to secondary pressure). In addition, in the third embodiment, the pressure equalizing passage 10a, which serves as the pressure introduction passage, is formed in the lower valve body 10, and there is no need to provide a pressure introduction passage in the needle 30, so that the needle 30 and the valve port 12 can be made thinner, and as a result, the pressure regulating valve 100C can be made smaller and accommodate small flow rates. Furthermore, in the third embodiment, by adopting the joint 1a' of the primary side joint 1' instead of the joint connector 3, problems associated with the joint connector 3 (e.g., high manufacturing costs, high inventory management costs, the effect of burrs occurring in the pressure introduction passage, etc.) can be eliminated, and the joint 1a' can be formed by extremely simple machining, so that the manufacturing and assembly time can be significantly reduced.

In the pressure regulating valve 100C of the third embodiment, as in the modified example of the first embodiment, the outer diameter D4' of the needle seal portion 34' can be set slightly larger than the valve port diameter D2 to resolve the new problem (increase in valve opening pressure due to secondary pressure).

＜Other＞
It goes without saying that the pressure regulating valves 100A, 100A', 100B, and 100C of the present embodiment are applicable not only to the refrigerant circuits illustrated, but also to any fluid devices and fluid circuits. Furthermore, the present invention is not limited to the above-described aspects, embodiments, and modified examples, and can be modified and changed as appropriate without departing from the technical concept of the present invention.

100A, 100A', 100B, 100C Pressure regulating valve 1, 1' Inlet pipe (primary side joint)
1a' Joint 1b' Base 1c' Inlet pipe (pressure introduction passage)
2 Outlet pipe 3, 3' joint connector (valve body)
3a Communication recess (pressure introduction path)
4. Thin tube (pressure introduction path)
5 Valve body 6 Valve spring 7 Seal member 10 Lower valve body (valve body)
10a Pressure equalizing path (pressure introduction path)
10b Spring accommodation groove (pressure introduction path)
10c Seal receiving groove 10d Communication recess (pressure introduction path)
10e: First communication hole (pressure introduction path)
10f: second communication hole (pressure introduction path)
11a: inlet port 11b: outlet port 12: valve port 13: valve chamber 14: needle guide hole 15: upper valve body (valve body)
17 Back pressure chamber 18 Valve seat member (valve body)
18a Valve seat 20 Spring case (valve body)
21: Spring accommodating chamber 22: Female thread portion 30, 30': Needle (valve body)
31 Needle guide portion 32 Valve portion 33 Spring support portion 34, 34' Needle seal portion 40 Pressure sensing unit 41 Pressure sensing bellows (pressure sensing member)
43 Bellows upper cover 43a Insertion hole 43c Slider 45 Connecting rod 50 Adjustment spring unit 51 Spring receiving member 52 Adjustment screw member 52a Male screw 53 Adjustment spring 60 Lower connection means 63 Lower ball 70 Upper connection means 71 Lower engagement portion 72 Upper engagement portion 73 Upper ball

a Effect of machining tolerance of valve port diameter b Effect of machining tolerance of average inner diameter of pressure-sensing bellows c Effect of machining tolerance of outer diameter of needle seal part C Central axis P1 Primary pressure P2 Secondary pressure Pop Valve opening pressure Psop Set valve opening pressure

Claims (5)

a valve body having a valve port;
a needle having a valve portion that can be connected to and disconnected from the valve port;
a pressure sensing unit having a pressure sensing member that is bent along an axial direction and biases the valve portion;
an adjusting spring unit having an adjusting spring that biases the valve portion in a valve closing direction via the pressure sensing unit;
a valve chamber in which the valve portion is disposed and into which secondary pressure is introduced;
a back pressure chamber located on the needle's side on the adjustment spring unit side and housing the pressure sensing member;
a pressure introduction passage communicating between the valve port and the back pressure chamber for introducing a primary side pressure into the back pressure chamber;
a seal member provided in a needle seal portion of the needle and separating the back pressure chamber from the valve chamber;
Equipped with
A pressure regulating valve, wherein an outer diameter of the needle seal portion and a diameter of the valve port are formed to be substantially the same. The pressure regulating valve according to claim 1, characterized in that the pressure introduction passage is provided in the valve body. a coupling connector is provided between a primary side coupling that introduces the primary side pressure into the valve port and the valve body;
2. The pressure regulating valve according to claim 1, wherein a communication recess communicating with the pressure introduction passage is formed in at least one of the valve body and the joint connector. The pressure regulating valve according to claim 2, characterized in that the primary side fitting that introduces the primary side pressure to the valve port comprises a base and a joint that has an inner diameter larger than the inner diameter of the base and communicates with the pressure introduction passage. The pressure regulating valve of claim 1, characterized in that the outer diameter of the needle seal portion is slightly larger than the valve port diameter.

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