PRESSURE REGULATOR VALVE

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a pressure regulating valve that regulates the pressure of a working liquid.BACKGROUND

[0002] For example, Japanese Unexamined Utility Model Publication No. S60-67471 describes a pressure regulating valve that regulates the pressure of an inflowing working liquid (liquid). Such a pressure regulating valve includes a valve seat unit that forms a surplus liquid discharge path for discharging a working liquid in the pressure regulating chamber, and a valve body that can sit on and separate from the valve seat unit. In such a pressure regulating valve, for example, a plurality of members such as a body and a valve seat unit forming a pressure regulating chamber may be used in combination. In this case, in order to prevent liquid leakage from an abutment portion of the member, a seal is provided on the abutment portion.SUMMARYProblems to Be Solved by The Invention

[0003] For example, in the case of regulating the pressure of an ultra-high pressure working liquid, it is likely to be difficult to certainly prevent leakage of the working liquid from the abutment portion of the member even though a seal is provided. An object of the present disclosure is to provide a pressure regulating valve capable of suppressing leakage of a working liquid to the outside from between a body and a valve seat unit even when leakage of the working liquid occurs in a seal provided between the body and the valve seat unit.Means for Solving The Problem

[0004] One aspect of the present disclosure is a pressure regulating valve configured to regulate the pressure of a working liquid. A pressure regulating valve (100, 100A) includes a body (1) forming a pressure regulating chamber (10) for regulating a pressure of an inflowing working liquid, an attachment hole (1d) provided in the body (1) and communicating with the pressure regulating chamber (10), a valve seat unit (2) fitted in the attachment hole (1d) and forming a surplus liquid discharge path (L) for discharging the working liquid in the pressure regulating chamber (10), and a piston valve body (3). The piston valve body (3) includes a part positioned inside the pressure regulating chamber (10), and the piston valve body (3) is configured to sit on the valve seat unit (2) to close an opening (La) of the surplus liquid discharge path (L) when the pressure of the working liquid is equal to or lower than a set pressure and separate from the valve seat unit (2) to open the opening (La) when the pressure of the working liquid exceeds the set pressure. A valve seat seal (8) sealing between the body (1) and the valve seat unit (2) in a liquid-tight manner is provided between the body (1) and the valve seat unit (2) in the attachment hole (1d). A return flow path opening (L10a) provided in an outer peripheral surface (22a) of the valve seat unit (2) at a position facing an inner peripheral surface (1f) of the attachment hole (1d), and a first return flow path (L10) connecting the return flow path opening (L10a) and the surplus liquid discharge path (L) are formed in the valve seat unit (2). The valve seat seal (8) is disposed between the return flow path opening (L10a) and the pressure regulating chamber (10) between the body (1) and the valve seat unit (2).

[0005] The valve seat unit (2) of the pressure regulating valve (100, 100A) is provided with the first return flow path (L10) communicating with the surplus liquid discharge path (L). The valve seat seal (8) is disposed between the return flow path opening (L10a) and the pressure regulating chamber (10). That is, even when the working liquid in the pressure regulating chamber (10) enters the body (1) and the valve seat unit (2) and leaks out from the valve seat seal (8), the leaked working liquid is discharged to the surplus liquid discharge path (L) through the first return flow path (L10). In this manner, in the pressure regulating valve (100, 100A), even when the working liquid leaks in the valve seat seal (8) provided between the body (1) and the valve seat unit (2), it is possible to suppress leakage of the working liquid to the outside from between the body (1) and the valve seat unit (2).

[0006] In the pressure regulating valve (100, 100A), the valve seat seal (8) may have a metal seal structure in which a tapered portion (1ft) formed in a tapered shape on the inner peripheral surface (1f) of the attachment hole (1d) of the body (1) and a tapered portion (21at) formed in a tapered shape on the outer peripheral surface (21a) of the valve seat unit (2) are brought into surface contact with each other. In this case, the pressure regulating valve (100, 100A) can seal the abutment portion between the body (1) and the valve seat unit (2) without using another seal member such as an O-ring.

[0007] In the pressure regulating valve (100, 100A), the valve seat unit (2) may include a valve seat (21) and an adapter (22) provided adjacent to the valve seat. The surplus liquid discharge path (L) may formed by the valve seat (21) and the adapter (22), the valve seat (21) may be provided with the opening (La) of the surplus liquid discharge path (L) opened and closed when the piston valve body (3) is seated, the first return flow path (L10) may be formed in the adapter (22), and the valve seat seal (8) may be provided between the body (1) and the valve seat (21). Here, for example, in the case of regulating the pressure of an ultra-high pressure working liquid, a portion of the valve seat unit (2) on which the valve body (3) abuts is required to have high hardness. The valve seat unit (2) is configured using, for example, the valve seat (21) and the adapter (22). This allows the pressure regulating valve (100, 100A) to form the valve seat unit (2) using a material having necessary characteristics at necessary portions.

[0008] In the pressure regulating valve (100, 100A), the first return flow path (L10) may be formed by at least either a valve seat groove (21d) provided on an end surface (21c) abutting on the adapter (22) in the valve seat (21) or an adapter groove (22d) provided on an end surface (22c) abutting on the valve seat (21) in the adapter (22). In this case, in the pressure regulating valve (100, 100A), the first return flow path (L10) can be easily formed by the groove provided in the valve seat (21) and / or the adapter (22).

[0009] The body (1) may be provided with a guide hole (1e) configured to guide movement of the piston valve body (3) when the piston valve body (3) sits or separates. The pressure regulating valve (100, 100A) may include a valve body seal (4) sealing between an inner peripheral surface (1g) of the guide hole (1e) and an outer peripheral surface (32a) of the piston valve body (3) in a liquid-tight manner, and a second return flow path (L20) connecting a guide hole opening (L20a) provided on the inner peripheral surface (1g) of the guide hole (1e) and an attachment hole opening (L20b) provided on the inner peripheral surface (1f) of the attachment hole (1d). The valve body seal (4) may be disposed between the guide hole opening (L20a) and the pressure regulating chamber (10).

[0010] In the pressure regulating valve (100, 100A), for example, a second return flow path (L20) formed by the body (1) may be formed. The valve body seal (4) is disposed between the guide hole opening (L20a) and the pressure regulating chamber (10). Even when the working liquid in the pressure regulating chamber (10) enters between the inner peripheral surface (1g) of the guide hole (1e) of the body (1) and the outer peripheral surface (32a) of the piston valve body (3) and leaks from the valve body seal (4), the leaked working liquid is discharged to the surplus liquid discharge path (L) via the second return flow path (L20). Thus, according to the pressure regulating valve (100, 100A), even when leakage of the working liquid occurs in the valve body seal (4) provided between the guide hole (1e) of the body (1) and the piston valve body (3), leakage of the working liquid to the outside from between the guide hole (1e) of the body (1) and the piston valve body (3) can be suppressed.

[0011] The pressure regulating valve (100, 100A) may further include a guide hole seal part (R2) disposed between the body (1) and the piston valve body (3) in the guide hole (1e) and sealing between the body (1) and the piston valve body (3) in a liquid-tight manner. The guide hole opening (L20a) may be disposed between the guide hole seal part (R2) and the pressure regulating chamber (10).

[0012] The pressure regulating valve (100, 100A) may further include a second valve seat seal (R1) disposed between the body (1) and the valve seat unit (2) in the attachment hole (1d) and sealing between the body (1) and the valve seat unit (2) in a liquid-tight manner.

[0013] The attachment hole opening (L20b) may be disposed between the second valve seat seal (R1) and the pressure regulating chamber (10). The return flow path opening (L10a) may be disposed between the second valve seat seal (R1) and the pressure regulating chamber (10).

[0014] The pressure regulating valve (100, 100A) may further include a spring part (60) configured to oppose the pressure of the working liquid in the pressure regulating chamber (10) and bias the piston valve body (3) in a direction of closing the opening (La).

[0015] The pressure regulating valve (100, 100A) may further include a spring cylinder (5) connected to the body (1) and housing a part of the piston valve body (3), and the spring part (60) may include a plurality of disc springs (6) housed in the spring cylinder (5).

[0016] The piston valve body (3) may include a valve part (31) configured to sit on the valve seat unit (2), and a valve rod (32) abutting on the valve part (31) and biased by the spring part (60).

[0017] One aspect of the present disclosure is a pressure regulating valve (100, 100A) configured to adjust a pressure of a working liquid. The pressure regulating valve (100, 100A) includes a body (1) including a pressure regulating chamber (10) into which the working liquid flows and an attachment hole (1d) communicating with the pressure regulating chamber (10), a valve seat assembly (2) fitted in the attachment hole (1d) and attached to the body (1), the valve seat assembly (2) including a surplus liquid discharge path (L) fluidly coupled to the pressure regulating chamber (10), a piston valve body (3) configured to open and close an opening (La) of the surplus liquid discharge path (L) in the pressure regulating chamber (10), a valve seat seal (8) sealing between the valve seat assembly (2) and the body (1) in the attachment hole (1d) in a liquid-tight manner, and a return flow path (L10) fluidly connecting an inside of the attachment hole (1d) and the surplus liquid discharge path (L). The valve seat seal (8) is disposed between the return flow path (L10) and the pressure regulating chamber (10).

[0018] The pressure regulating valve (100, 100A) may further include a second valve seat seal (R1) sealing between the valve seat assembly (2) and the body (1) in the attachment hole (1d) in a liquid-tight manner, and the return flow path (L10) may be disposed between the valve seat seal (8) and the second valve seat seal (R1).

[0019] The valve seat seal (8) may include a seal surface (21at) formed on an outer peripheral surface (21a) of the valve seat assembly (2), and a seal receiving surface (1ft) formed on an inner peripheral surface (1f) of the attachment hole (1d) and brought into surface contact with the seal surface (21at).Advantageous Effects of The Invention

[0020] According to the present disclosure, it is possible to suppress leakage of a working liquid to the outside from between a body and a valve seat unit even when leakage of the working liquid occurs in a seal provided between the body and the valve seat unit.BRIEF DESCRIPTION OF THE DRAWINGS

[0021] FIG. 1 is a longitudinal sectional view of a pressure regulating valve according to an embodiment; FIG. 2 is a longitudinal sectional view of a pressure regulating valve according to a modification; FIG. 3A is a longitudinal sectional view illustrating an adapter according to a modification; and FIG. 3B is a longitudinal sectional view illustrating a valve seat according to a modification. DETAILED DESCRIPTION

[0022] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the drawings, the same or corresponding elements are denoted by the same reference numerals, and redundant description will be omitted. In the present specification, phrases such as "upper" and "lower" are based on the state illustrated in the drawings and are for convenience in describing the configuration.

[0023] A pressure regulating valve 100 illustrated in FIG. 1 is a so-called differential pressure type pressure regulating valve. As an example, the pressure regulating valve 100 is used in a power sprayer, a cleaner, or the like that sprays a working liquid such as an agricultural chemical, a chemical liquid, a cleaning liquid, or a disinfectant. The pressure regulating valve 100 is attached to a discharge side of a pump that discharges the working liquid, and regulates the pressure of the working liquid discharged from the pump. In the following description, "communicate" means, for example, fluidly coupled.

[0024] The pressure regulating valve 100 includes a body 1, a valve seat assembly (for example, a valve seat unit 2), a piston valve body 3, a valve body seal 4, a spring cylinder 5, a spring part 60, and a pressure regulating cap 7. The spring part 60 includes, for example, a plurality of disc springs 6. The spring part 60 may be another elastic body such as a coil spring.

[0025] An inlet 1a is formed in a side portion of the body 1. An outlet 1b is formed on a side portion of the body 1 opposite to the inlet 1a. A pressure regulating chamber 10 is formed in the body 1. The inlet 1a and the outlet 1b communicate with each other via the pressure regulating chamber 10. The pressure regulating chamber 10 is a chamber for regulating the pressure of the inflowing working liquid. For example, the inlet 1a is connected to a discharge port of a pump, and the outlet 1b is connected to an injection nozzle via a pipe or the like.

[0026] An attachment hole 1d extending in up-down directions is formed in the lower surface of the body 1. The upper end of the attachment hole 1d communicates with the pressure regulating chamber 10. A guide hole 1e extending in the up-down directions is formed in the upper surface of the body 1. The lower end of the guide hole 1e communicates with the pressure regulating chamber 10. The guide hole 1e guides the movement of the piston valve body 3 when the piston valve body 3 sits on and separates from the valve seat unit 2.

[0027] The valve seat unit 2 has a cylindrical shape having an axis in the up-down directions. A cylinder hole of the valve seat unit 2 constitutes a surplus liquid discharge path L for discharging the working liquid in the pressure regulating chamber 10. The surplus liquid discharge path L communicates with the pressure regulating chamber 10. The valve seat unit 2 is fitted into the attachment hole 1d provided in the body 1 and attached to the body 1. An upper portion of the valve seat unit 2 is in the pressure regulating chamber 10. A lower end portion of the surplus liquid discharge path L serves as a surplus liquid port 1c for discharging the working liquid in the pressure regulating chamber 10 to the outside of the pressure regulating valve 100. For example, the surplus liquid port 1c is connected to a tank to which a pump is connected via a pipe or the like.

[0028] An upper portion of the piston valve body 3 opens and closes an opening La of the surplus liquid discharge path L in the pressure regulating chamber 10. The piston valve body 3 has a rod shape having an axis in the up-down directions, and is disposed coaxially with the valve seat unit 2. The piston valve body 3 is inserted into the guide hole 1e of the body 1 so as to be movable in the up-down directions. In the present embodiment, the piston valve body 3 includes a valve part 31 and a valve rod 32.

[0029] The valve part 31 is disposed below the valve rod 32. The valve part 31 is seated on an upper portion of the valve seat unit 2 from the upper side in the pressure regulating chamber 10. That is, a part of the piston valve body 3 (the lower end of the valve unit 31) is in the pressure regulating chamber 10. In FIG. 1, a state in which the valve part 31 of the piston valve body 3 is seated on the valve seat unit 2 is illustrated.

[0030] A valve body seal 4 having an annular shape is provided between the outer peripheral surface of the valve part 31 and an inner peripheral surface 1g of the guide hole 1e. The valve body seal 4 seals between the outer peripheral surface of the valve part 31 and the inner peripheral surface 1g of the guide hole 1e in a liquid-tight manner. The valve part 31 is guided in the up-down directions by the guide hole 1e via the valve body seal 4. A high-pressure working liquid pressurized by a pump or the like flows into the pressure regulating chamber 10. Thus, for the valve body seal 4, one can withstand high pressure is used.

[0031] The valve rod 32 is disposed coaxially with the valve part 31. A lower end portion of the valve rod 32 abuts on an upper end portion of the valve part 31. A lower portion of the valve rod 32 has a columnar shape and is inserted into the guide hole 1e. An upper portion of the valve rod 32 receives a biasing force of the spring part 60 (for example, the disc spring 6). That is, the valve rod 32 functions as a spring receiver that receives the biasing force of the disc spring 6. A part of the valve rod 32 (a part of the piston valve body 3) is housed in the spring cylinder 5.

[0032] The spring cylinder 5 has a cylindrical shape having an axis in the up-down directions, and is disposed coaxially with the piston valve body 3 at a position of an upper portion of the body 1. The spring cylinder 5 is fixed to the body 1 by being screwed to the upper portion of the body 1.

[0033] The plurality of disc springs 6 oppose the pressure of the working liquid in the pressure regulating chamber 10 and bias the piston valve body 3 in a direction of closing the opening La. The plurality of disc springs 6 are stacked in the up-down directions in the cylinder hole of the spring cylinder 5. The plurality of disc springs 6 are disposed in a compressed state in the cylinder hole of the spring cylinder 5, and bias the valve rod 32 of the piston valve body 3 in the axial direction. This causes the valve part 31 of the piston valve body 3 to be biased in a direction of sitting on the valve seat unit 2. The valve rod 32 closes the opening La by covering the opening La of the surplus liquid discharge path L on the pressure regulating chamber 10 side. The biasing means for biasing the piston valve body 3 is not limited to the disc spring 6, and may be another member such as a compression coil spring.

[0034] When the pressure of the working liquid supplied from the inlet 1a to the pressure regulating chamber 10 is equal to or lower than a set pressure, the piston valve body 3 sits on the valve seat unit 2 so as to cover the opening La of the surplus liquid discharge path L provided in the valve seat unit 2, and closes the opening La.

[0035] On the other hand, when the pressure of the supplied working liquid exceeds the set pressure, the piston valve body 3 moves upward so as to compress the disc spring 6, and separates from the valve seat unit 2. This causes the piston valve body 3 to open the opening La of the surplus liquid discharge path L. In this manner, the pressure regulating valve 100 regulates the pressure of the working liquid by discharging a part of the working liquid to the outside through the surplus liquid discharge path L and the surplus liquid port 1c, and can discharge the working liquid with the regulated pressure from the outlet 1b.

[0036] The pressure regulating cap 7 is screwed to an upper portion of the spring cylinder 5. The lower end of the pressure regulating cap 7 abuts on an upper portion of the plurality of disc springs 6. Adjusting the position of the pressure regulating cap 7 in the up-down directions causes the initial load of the plurality of disc springs 6 disposed between the pressure regulating cap 7 and the valve rod 32 of the piston valve body 3 to be adjusted.

[0037] Next, details of the valve seat unit 2 will be described. The valve seat unit 2 includes a valve seat 21 and an adapter 22 provided adjacent to the valve seat 21. The adapter 22 is provided adjacent to the lower side of the valve seat 21. The surplus liquid discharge path L is formed of the valve seat 21 and the adapter 22. That is, the surplus liquid discharge path L penetrates the valve seat 21 and the adapter 22 in the up-down directions. The opening La of the surplus liquid discharge path L is provided at the upper end of the valve seat 21. The valve part 31 of the piston valve body 3 sitting on and separating from the upper portion of the valve seat 21 causes the opening La of the surplus liquid discharge path L to open and close.

[0038] In the attachment hole 1d of the body 1, a valve seat seal 8 that seals between the body 1 and the valve seat unit 2 is provided between the body 1 and the valve seat unit 2 in a liquid-tight manner. For example, the valve seat seal 8 is provided between the body 1 and the valve seat 21. The valve seat seal 8 may be provided between the body 1 and the adapter 22. The valve seat seal 8 has a metal seal structure in which a tapered portion 1ft formed in a tapered shape on an inner peripheral surface 1f of the attachment hole 1d of the body 1 and a tapered portion 21at formed in a tapered shape on an outer peripheral surface 21a of the valve seat 21 of the valve seat unit 2 are brought into surface contact with each other. The tapered portion 21at is an example of a seal surface formed on an outer peripheral surface 22a of the valve seat unit 2. The tapered portion 1ft is an example of a seal receiving surface formed on the inner peripheral surface 1f of the attachment hole 1d and in surface contact with the tapered portion 21at.

[0039] The valve seat unit 2 is provided with a return flow path opening (for example, an opening L10a) in the outer peripheral surface of the valve seat unit 2 at a position facing the inner peripheral surface 1f of the attachment hole 1d. In the valve seat unit 2, a return flow path (for example, a first return flow path L10) connecting the opening L10a and the surplus liquid discharge path L is formed. For example, the first return flow path L10 is provided in the adapter 22. That is, the first return flow path L10 connects the opening L10a provided in the outer peripheral surface 22a of the adapter 22 at a position facing the inner peripheral surface 1f of the attachment hole 1d and the surplus liquid discharge path L. The first return flow path L10 extends along a direction orthogonal to the surplus liquid discharge path L. The first return flow path L10 may be provided in the valve seat 21.

[0040] An outer peripheral surface of the valve seat unit 2, for example, an outer peripheral surface 22a of the adapter 22 is provided with a catch flow path (for example, a groove 22b) extending in a circumferential direction. The circumferential direction means, for example, a circumferential direction in a case where the valve seat unit 2 is assumed to have a cylindrical shape. The groove 22b is provided to annularly surround the surplus liquid discharge path L. For example, the groove 22b is provided without interruption over the entire circumference in the circumferential direction of the valve seat unit 2. The groove 20b passes through the position of the opening L10a of the first return flow path L10. The space formed by the inner peripheral surface 1f of the attachment hole 1d and the groove 22b communicates with the first return flow path L10 via the opening L10a. The working liquid that has leaked from the valve seat seal 8 is captured by the groove 22b and guided to the first return flow path L10.

[0041] Between the inner peripheral surface 1f of the attachment hole 1d of the body 1 and the outer peripheral surface of the valve seat unit 2 (the outer peripheral surface 21a of the valve seat 21), the valve seat seal 8 is positioned closer to the pressure regulating chamber 10 than the opening L10a of the first return flow path L10 on the outer peripheral surface 22a side of the adapter 22. For example, the valve seat seal 8 is disposed between the opening L10a and the pressure regulating chamber 10.

[0042] A second valve seat seal (for example, an O-ring R1) is disposed between the body 1 and the valve seat unit 2 in the attachment hole 1d. The O-ring R1 seals between the body 1 and the valve seat unit 2 in a liquid-tight manner. An annular ring groove is formed in the outer peripheral surface 22a of the adapter 22 at a position facing the inner peripheral surface 1f of the attachment hole 1d. The O-ring R1 is, for example, fitted into the ring groove. The first return flow path L10 is disposed between the valve seat seal 8 and the O-ring R1. The first return flow path L10 is provided such that the opening L10a of the first return flow path L10 on the outer peripheral surface 22a side of the adapter 22 is positioned closer to the valve seat seal 8 than the O-ring R1. For example, between the inner peripheral surface 1f of the attachment hole 1d of the body 1 and the outer peripheral surface of the valve seat unit 2, the opening L10a of the first return flow path L10 is positioned between the valve seat seal 8 and the O-ring R1. When the O-ring R1 attached to the adapter 22 is brought into pressure contact with the inner peripheral surface 1f of the attachment hole 1d of the body 1, the adapter 22 is attached to the body 1 in a liquid-tight manner.

[0043] In this manner, the valve seat unit 2 of the pressure regulating valve 100 is provided with the first return flow path L10 communicating with the surplus liquid discharge path L. The valve seat seal 8 is disposed between the opening L10a provided on the outer peripheral surface 22a of the adapter 22 and the pressure regulating chamber 10. That is, even when the working liquid in the pressure regulating chamber 10 enters between the inner peripheral surface 1f of the attachment hole 1d of the body 1 and the outer peripheral surface of the valve seat unit 2 and leaks out from the valve seat seal 8, the leaked working liquid is discharged to the surplus liquid discharge path L through the first return flow path L10. In this manner, in the pressure regulating valve 100, even when the working liquid leaks in the valve seat seal 8 provided between the body 1 and the valve seat unit 2, it is possible to suppress leakage of the working liquid to the outside from between the body 1 and the valve seat unit 2.

[0044] The O-ring R1 is provided between the body 1 and the valve seat unit 2. The opening L10a of the first return flow path L10 is positioned closer to the valve seat seal 8 than the O-ring R1. For example, the opening L10a is disposed between the valve seat seal 8 and the O-ring R1. This allows the O-ring R1 to suppress leakage of the working liquid that has leaked from the valve seat seal 8 to the outside of the pressure regulating valve 100 from between the body 1 and the valve seat unit 2.

[0045] The pressure of the working liquid that has leaked from the valve seat seal 8 is lower than the pressure of the working liquid in the pressure regulating chamber 10. Thus, the O-ring R1 does not have to be configured to withstand high pressure like the valve seat seal 8. Thus, as the O-ring R1, an O-ring or the like having a simple configuration for low pressure can be adopted.

[0046] The O-ring R1 is not limited to being mounted in the ring groove provided in the outer peripheral surface 22a of the adapter 22. The O-ring R1 may be fitted into a ring groove provided in the inner peripheral surface 1f of the attachment hole 1d of the body 1.

[0047] The valve seat seal 8 includes a seal surface (for example, the tapered portion 21at) formed on the outer peripheral surface (for example, the outer peripheral surface 21a of the valve seat 21) of the valve seat unit 2 and a seal receiving surface (for example, the tapered portion 1ft) formed on the inner peripheral surface 1f of the attachment hole 1d and in surface contact with the seal surface. For example, the valve seat seal 8 has a metal seal structure in which the tapered portion 1ft of the body 1 and the tapered portion 21at of the valve seat 21 are brought into surface contact with each other. In this case, the pressure regulating valve 100 can seal the abutment portion between the body 1 and the valve seat unit 2 without using another seal member such as an O-ring.

[0048] The valve seat unit 2 includes the valve seat 21 and the adapter 22. The valve part 31 of the piston valve body 3 is seated on the valve seat 21. The adapter 22 is provided with the first return flow path L10. For example, in the case of regulating the pressure of an ultra-high pressure working liquid, a portion of the valve seat unit 2 on which the valve part 31 abuts is required to have high hardness. For example, the valve seat unit 2 of the pressure regulating valve 100 includes the valve seat 21 and the adapter 22 that are separate bodies. This allows the pressure regulating valve 100 to form the valve seat unit 2 using a material having necessary characteristics at necessary portions. For example, a material having a hardness higher than that of the adapter 22 can be used as a material forming the valve seat 21. In the pressure regulating valve 100, the first return flow path L10 can be easily formed with respect to the adapter 22 having a hardness lower than that of the valve seat 21.

[0049] Next, a modification of the pressure regulating valve will be described. Hereinafter, differences from the pressure regulating valve 100 according to the embodiment will be mainly described. As illustrated in FIG. 2, a pressure regulating valve 100A according to the modification is further provided with a second return flow path L20 as compared with the pressure regulating valve 100 according to the above-described embodiment. FIG. 2 illustrates a section at an angle different from that in FIG. 1. Also in the pressure regulating valve 100A illustrated in FIG. 2, as in the pressure regulating valve 100 illustrated in FIG. 1, the inlet 1a and the outlet 1b communicating with the pressure regulating chamber 10 are provided at positions not illustrated.

[0050] The second return flow path L20 connects a guide hole opening (for example, an opening L20a) provided on the inner peripheral surface 1g of the guide hole 1e of the body 1 and an attachment hole opening (for example, an opening L20b) provided on the inner peripheral surface 1f of the attachment hole 1d of the body 1. At least a part of the second return flow path L20 is formed in the body 1. The pressure regulating valve 100A includes a flow path forming part 9 attached to the body 1. A flow path L21 extending from one end to the other end is formed inside the flow path forming part 9. In the present modification, the second return flow path L20 is formed by the body 1 and the flow path forming part 9.

[0051] The flow path forming part 9 includes a first socket 91, a second socket 92, and a pipe 93. The first socket 91 and the second socket 92 are attached to the body 1. The pipe 93 connects the first socket 91 and the second socket 92. The flow path L21 is formed by the first socket 91, the pipe 93, and the second socket 92.

[0052] The body 1 is provided with flow path holes L22 and L23. The flow path hole L22 extends from the inner peripheral surface 1g of the guide hole 1e of the body 1 toward the side surface of the body 1. The flow path hole L23 extends from the inner peripheral surface 1f of the attachment hole 1d of the body 1 toward the side surface of the body 1. The flow path hole L22 and the flow path L21 in the first socket 91 communicate with each other. The flow path hole L23 and the flow path L21 in the second socket 92 communicate with each other. That is, the opening at the end of the flow path hole L22 on the inner peripheral surface 1g side of the guide hole 1e is the opening L20a at one end of the second return flow path L20. The opening at the end of the flow path hole L23 on the inner peripheral surface 1f side of the attachment hole 1d is the opening L20b of the other end of the second return flow path L20.

[0053] The valve body seal 4 is positioned closer to the pressure regulating chamber 10 than the opening L20a on the inner peripheral surface 1g side of the guide hole 1e in the second return flow path L20. For example, the valve body seal 4 is disposed between the opening L20a and the pressure regulating chamber 10. The inner peripheral surface 1g of the guide hole 1e of the body 1 is provided with a ring groove extending along the circumferential direction. A guide hole seal part (for example, an O-ring R2) is fitted into a ring groove provided in the inner peripheral surface 1g. The O-ring R2 seals between an outer peripheral surface 32a of the valve rod 32 and the inner peripheral surface 1g of the guide hole 1e of the body 1 in a liquid-tight manner. The opening L20a is positioned closer to the pressure regulating chamber 10 (valve body seal 4) than to the O-ring R2. For example, the opening L20a is disposed between the O-ring R2 and the pressure regulating chamber 10. The opening L20b of the second return flow path L20 is positioned closer to the pressure regulating chamber 10 (valve seat seal 8) than the O-ring R1. For example, the opening L20b is disposed between the O-ring R1 and the pressure regulating chamber 10.

[0054] The outer peripheral surface 22a of the adapter 22 is provided with a catch flow path (for example, the groove 22b) extending in the circumferential direction. For example, the groove 22b passes through the opening L10a of the first return flow path L10 and the opening L20b of the second return flow path L20. The space formed by the inner peripheral surface 1f of the attachment hole 1d and the groove 22b communicates with the first return flow path L10 via the opening L10a and communicates with the second return flow path L20 via the opening L20b.

[0055] The pressure regulating valve 100A includes the second return flow path L20 formed by the body 1 and the flow path forming part 9. The valve body seal 4 is positioned closer to the pressure regulating chamber 10 than the opening L20a on the inner peripheral surface 1g side of the guide hole 1e in the second return flow path L20. The valve body seal 4 is disposed between the opening L20a and the pressure regulating chamber 10. Thus, even when the working liquid in the pressure regulating chamber 10 leaks from the valve body seal 4, the leaked working liquid is guided to the attachment hole 1d side of the body 1 via the second return flow path L20. The first return flow path L10 is formed in the adapter 22 of the valve seat unit 2 fitted in the attachment hole 1d. Thus, the working liquid guided into the attachment hole 1d of the body 1 through the second return flow path L20 is discharged to the surplus liquid discharge path L through the first return flow path L10. The outer peripheral surface 22a of the adapter 22 is provided with a catch flow path (for example, the groove 22b) extending in the circumferential direction. The working liquid guided into the attachment hole 1d of the body 1 through the second return flow path L20 is guided to the first return flow path L10 by the groove 22b.

[0056] In this manner, in the pressure regulating valve 100A, even when leakage of the working liquid occurs in the valve body seal 4 provided between the guide hole 1e of the body 1 and the piston valve body 3, leakage of the working liquid to the outside from between the guide hole 1e of the body 1 and the piston valve body 3 can be suppressed.

[0057] The O-ring R2 is provided between the body 1 and the piston valve body 3 (valve rod 32). The opening L20a of the second return flow path L20 is positioned closer to the valve body seal 4 than the O-ring R2. The opening L20a is disposed between the O-ring R2 and the valve body seal 4. This allows the O-ring R2 to suppress leakage of the working liquid that has leaked from the valve body seal 4 to the outside of the body 1 from between the guide hole 1e of the body 1 and the piston valve body 3.

[0058] The pressure of the working liquid that has leaked from the valve body seal 4 is lower than the pressure of the working liquid in the pressure regulating chamber 10. Thus, the O-ring R2 does not have to be configured to withstand high pressure like the valve body seal 4. Thus, as the O-ring R2, an O-ring or the like having a simple configuration for low pressure can be adopted.

[0059] The O-ring R2 is not limited to being fitted in the ring groove provided in the inner peripheral surface 1g of the guide hole 1e of the body 1. The O-ring may be mounted in a ring groove provided in the outer peripheral surface of the piston valve body 3 (the outer peripheral surface 32a of the valve rod 32).

[0060] The piston valve body 3 moves to regulate the pressure of the working liquid. Thus, liquid leakage is likely to occur from the valve body seal 4. In the pressure regulating valve 100A, since the working liquid that has leaked from the valve body seal 4 can be discharged to the surplus liquid discharge path L, liquid leakage from the valve body seal 4 can be allowed to some extent. This makes it possible to reduce the replacement frequency of the valve body seal 4 in the pressure regulating valve 100A.

[0061] Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above embodiments. For example, the first return flow path L10 is not limited to being formed by a hole provided in the adapter 22 of the valve seat unit 2. For example, as illustrated in FIG. 3A, the first return flow path L10A may be formed by an adapter groove 22d provided in an upper end surface 22c of the adapter 22. The end surface 22c is a surface that abuts on the lower end surface of the valve seat 21. The adapter groove 22d (first return flow path L10A) extends from the outer peripheral surface 22a of the adapter 22 to the surplus liquid discharge path L. This forms the first return flow path L10A that connects a position in the outer peripheral surface of the valve seat unit 2 facing the inner peripheral surface 1f of the attachment hole 1d of the body 1 and the surplus liquid discharge path L in a state where the valve seat 21 abuts on the upper end surface 22c of the adapter 22.

[0062] In addition, for example, as illustrated in FIG. 3B, the first return flow path L10B may be formed by a valve seat groove 21d provided on a lower end surface 21c of the valve seat 21. The end surface 21c is a surface that abuts on the upper end surface of the adapter 22. The valve seat groove 21d (first return flow path L10B) extends from the outer peripheral surface 21a of the valve seat 21 to the surplus liquid discharge path L. This forms the first return flow path L10B that connects a position in the outer peripheral surface of the valve seat unit 2 facing the inner peripheral surface 1f of the attachment hole 1d of the body 1 and the surplus liquid discharge path L in a state where the adapter 22 abuts on the lower end surface 21c of the valve seat 21.

[0063] The same effect as that in a case where the first return flow path L10 is provided can be obtained in a case where the first return flow paths L10A and L10B are provided instead of the first return flow path L10. In these modifications, the first return flow paths L10A and L10B can be easily formed by the valve seat groove 21d and the adapter groove 22d. The first return flow path L10A and the first return flow path L10B may be used simultaneously.

[0064] In the embodiments and the modifications described above, the valve seat seal 8 is formed of a metal seal structure. The valve seat seal is not limited to this configuration, and the valve seat seal 8 may be formed of a seal member.Reference Signs List

[0065] 1body 1dattachment hole 1eguide hole 1finner peripheral surface 1fttapered portion (seal receiving surface) 2valve seat unit 3piston valve body 4valve body seal 6disc spring 8valve seat seal 10pressure regulating chamber 21valve seat 21aouter peripheral surface 21attapered portion (seal surface) 21cend surface 21dvalve seat groove 22adapter 22aouter peripheral surface 22cend surface 22dadapter groove 32aouter peripheral surface 60spring part 100, 100Apressure regulating valve Lsurplus liquid discharge path Laopening L10first return flow path (return flow path) L10aopening (return flow path opening) L20second return flow path L20aopening (guide hole opening) L20bopening (attachment hole opening) R1O-ring (second valve seat seal) R2O-ring (guide hole seal part)

Claims

1. A pressure regulating valve (100, 100A) configured to regulate a pressure of a working liquid, the pressure regulating valve comprising: a body (1) forming a pressure regulating chamber (10) for regulating a pressure of an inflowing working liquid; an attachment hole (1d) provided in the body (1) and communicating with the pressure regulating chamber (10); a valve seat unit (2) fitted in the attachment hole (1d) and forming a surplus liquid discharge path (L) for discharging the working liquid in the pressure regulating chamber (10); and a piston valve body (3) including a part positioned inside the pressure regulating chamber (10), the piston valve body (3) being configured to sit on the valve seat unit (2) to close an opening (La) of the surplus liquid discharge path (L) when the pressure of the working liquid is equal to or lower than a set pressure and separate from the valve seat unit (2) to open the opening (La) when the pressure of the working liquid exceeds the set pressure, wherein a valve seat seal (8) sealing between the body (1) and the valve seat unit (2) in a liquid-tight manner is provided between the body (1) and the valve seat unit (2) in the attachment hole (1d), characterised in that a return flow path opening (L10a) provided in an outer peripheral surface (22a) of the valve seat unit (2) at a position facing an inner peripheral surface (1f) of the attachment hole (1d), and a return flow path (L10) connecting the return flow path opening (L10a) and the surplus liquid discharge path (L) are formed in the valve seat unit (2), and the valve seat seal (8) is disposed between the return flow path opening (L10a) and the pressure regulating chamber (10) between the body (1) and the valve seat unit (2).

2. The pressure regulating valve (100, 100A) according to claim 1, wherein the valve seat seal (8) has a metal seal structure in which a tapered portion (1ft) formed in a tapered shape on the inner peripheral surface (1f) of the attachment hole (1d) of the body (1) and a tapered portion (21at) formed in a tapered shape on the outer peripheral surface (21a) of the valve seat unit (2) are brought into surface contact with each other.

3. The pressure regulating valve (100, 100A) according to claim 1, wherein the valve seat unit (2) includes a valve seat (21) and an adapter (22) provided adjacent to the valve seat, the surplus liquid discharge path (L) is formed by the valve seat (21) and the adapter (22), the valve seat (21) is provided with the opening (La) of the surplus liquid discharge path (L) opened and closed when the piston valve body (3) is seated, the return flow path (L10) is formed in the adapter (22), and the valve seat seal (8) is provided between the body (1) and the valve seat (21).

4. The pressure regulating valve (100, 100A) according to claim 3, wherein the return flow path (L10) is formed by at least either a valve seat groove (21d) provided on an end surface (21c) abutting on the adapter (22) in the valve seat (21) or an adapter groove (22d) provided on an end surface (22c) abutting on the valve seat (21) in the adapter (22).

5. The pressure regulating valve (100, 100A) according to any one of claims 1 to 4, wherein the body (1) is provided with a guide hole (1e) configured to guide movement of the piston valve body (3) when the piston valve body (3) sits or separates, and the pressure regulating valve (100, 100A) includes: a valve body seal (4) sealing between an inner peripheral surface (1g) of the guide hole (1e) and an outer peripheral surface (32a) of the piston valve body (3) in a liquid-tight manner; and a second return flow path (L20) connecting a guide hole opening (L20a) provided on the inner peripheral surface (1g) of the guide hole (1e) and an attachment hole opening (L20b) provided on the inner peripheral surface (1f) of the attachment hole (1d).

6. The pressure regulating valve (100, 100A) according to claim 5, wherein the valve body seal (4) is disposed between the guide hole opening (L20a) and the pressure regulating chamber (10).

7. The pressure regulating valve (100, 100A) according to claim 6, the pressure regulating valve further comprising a guide hole seal part (R2) disposed between the body (1) and the piston valve body (3) in the guide hole (1e) and sealing between the body (1) and the piston valve body (3) in a liquid-tight manner, wherein the guide hole opening (L20a) is disposed between the guide hole seal part (R2) and the pressure regulating chamber (10).

8. The pressure regulating valve (100, 100A) according to claim 5, the pressure regulating valve further comprising a second valve seat seal (R1) disposed between the body (1) and the valve seat unit (2) in the attachment hole (1d) and sealing between the body (1) and the valve seat unit (2) in a liquid-tight manner, wherein the attachment hole opening (L20b) is disposed between the second valve seat seal (R1) and the pressure regulating chamber (10).

9. The pressure regulating valve (100, 100A) according to any one of claims 1 to 8, the pressure regulating valve further comprising a second valve seat seal (R1) disposed between the body (1) and the valve seat unit (2) in the attachment hole (1d) and sealing between the body (1) and the valve seat unit (2) in a liquid-tight manner, wherein the return flow path opening (L10a) is disposed between the second valve seat seal (R1) and the pressure regulating chamber (10).

10. The pressure regulating valve (100, 100A) according to any one of claims 1 to 9, the pressure regulating valve further comprising a spring part (60) configured to oppose the pressure of the working liquid in the pressure regulating chamber (10) and bias the piston valve body (3) in a direction of closing the opening (La).

11. The pressure regulating valve (100, 100A) according to claim 10, the pressure regulating valve further comprising a spring cylinder (5) connected to the body (1) and housing a part of the piston valve body (3), wherein the spring part (60) includes a plurality of disc springs (6) housed in the spring cylinder (5).

12. The pressure regulating valve (100, 100A) according to claim 10 or 11, wherein the piston valve body (3) includes a valve part (31) configured to sit on the valve seat unit (2), and a valve rod (32) abutting on the valve part (31) and biased by the spring part (60).