Relief valve

Abstract

To provide a relief valve that effectively restrains hunting caused by pressure fluctuations, and stabilizes valve behavior.SOLUTION: A relief valve 40 comprises a cylinder 42 comprising a cavity part 54, a valve element 44 capable of being displaced in the axial direction of the cylinder 42 in the cavity part 54, and a spring member 46 for biasing the valve element 44 toward a receiving seat part 58 of the cylinder 42. A head part 62 of the valve element 44 comprises a first surface 64 facing an inflow port 56 in the axial direction, a second surface 66 facing the receiving seat part 58 in the axial direction, a convex part 68 protruding toward the receiving seat part 58 from between the first surface 64 and the second surface 66, and a communication passage 70 provided in the convex part 68.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a relief valve. [Background technology]

[0002] In recent years, research and development into energy efficiency has been conducted in various fields, including the field of fluid circuits, in order to ensure that more people can have access to affordable, reliable, sustainable, and advanced energy. For example, as disclosed in Patent Document 1, a relief valve is arranged in a fluid circuit such as a hydraulic circuit to prevent the pressure from exceeding a predetermined pressure (set value). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-12627 Summary of the Invention [Problem to be solved by the invention]

[0004] It is desirable to effectively suppress hunting caused by pressure fluctuations in relief valves and stabilize valve behavior.

[0005] The present invention aims to solve the above-mentioned problems. [Means for solving the problem]

[0006] An aspect of the present disclosure is a relief valve comprising: a cylinder having a peripheral wall portion, a hollow portion formed within the peripheral wall portion, an inlet provided at one end of the peripheral wall portion and communicating with the hollow portion, a seat portion surrounding the inlet in the hollow portion, and an outlet port that can communicate with the inlet via the hollow portion; a valve body that is displaceable in the axial direction of the cylinder within the hollow portion and has a head portion provided with a seat surface facing the seat surface, the seat surface abutting against the seat surface in a closed valve state; and a spring member that urges the valve body toward the seat surface of the cylinder, wherein the head portion has a first surface facing the inlet in the axial direction, a second surface facing the seat surface in the axial direction, a convex portion that protrudes from between the first surface and the second surface toward the seat surface and on which the seat surface is formed, and a communicating passage provided in the convex portion that communicates between the first surface and the second surface. [Effects of the Invention]

[0007] According to the relief valve of the present invention, the protrusion and the communication passage are provided on the head of the valve body, which reduces the difference in pressure-receiving area before and after the valve is opened, thereby reducing pressure fluctuations (pressure pulsations) before and after the valve is opened. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram of a liquid supply system. [Figure 2] FIG. 2 is a cross-sectional view of the relief valve. [Figure 3] FIG. 3 is an enlarged cross-sectional view of the relief valve. [Figure 4] FIG. 4 is a perspective view of the valve body. [Figure 5] FIG. 5 is an enlarged view of the outlet port and its surroundings in the cylinder. DETAILED DESCRIPTION OF THE INVENTION

[0009] The liquid supply system 10 shown in FIG. 1 has a fluid circuit 12. The fluid circuit 12 is a liquid supply device 13. The fluid circuit 12 is configured as a lubrication circuit. The flow medium in the fluid circuit 12 is a liquid. In the lubrication circuit, a lubricating liquid flows as the flow medium. The lubricating liquid is, for example, oil. The liquid is supplied to a supply target 14. A device 15 having the supply target 14 is, for example, a rotating electric machine. The rotating electric machine is an electric motor or a generator. The supply target 14 is, for example, a sliding part, a bearing, etc.

[0010] The liquid supply system 13 includes a supply line 16, a supply pump 18, a heat exchanger 20, a filter 22, a return line 24, a return pump 26, and a tank 28.

[0011] The supply line 16 supplies the liquid to the supply target 14. The supply line 16 may be a pipe 17. A supply pump 18, a heat exchanger 20, and a filter 22 are provided on the supply line 16. The supply pump 18 generates a supply pressure for the liquid. The supply pump 18 supplies the liquid stored in a tank 28 to the supply target 14.

[0012] The heat exchanger 20 changes the temperature of the liquid flowing through the supply line 16. For example, the heat exchanger 20 cools the liquid flowing through the supply line 16. If cooling or heating of the liquid is not required, the heat exchanger 20 does not need to be provided. The filter 22 removes foreign matter from the liquid flowing through the supply line 16.

[0013] The recovery line 24 recovers the liquid that has passed through the supply target 14. The recovery line 24 may be a pipe 25. The recovery pump 26 is provided on the recovery line 24. The recovery pump 26 sends the liquid stored in the storage section 30 of the device 15 to a tank 28. The tank 28 stores the liquid.

[0014] To protect the fluid circuit 12 of the liquid supply device 13, the liquid supply device 13 further includes a relief valve 40. A bypass line 32a is provided in parallel with the supply pump 18. A relief valve 40a is disposed on the bypass line 32a. When the pressure of the liquid exceeds a set value, the relief valve 40a opens, causing a portion of the liquid to flow through the bypass line 32a and return to the inlet side of the supply pump 18. This adjusts the pressure to below the set value.

[0015] A bypass line 32b is provided in parallel with the heat exchanger 20. A relief valve 40b is arranged on the bypass line 32b. When the pressure of the liquid exceeds a set value, the relief valve 40b opens, causing a portion of the liquid to flow through the bypass line 32b and bypass the heat exchanger 20 downstream. This adjusts the pressure of the liquid to below the set value, protecting the heat exchanger 20.

[0016] A bypass line 32c is provided in parallel with the filter 22. A relief valve 40c is disposed on the bypass line 32c. When the pressure of the liquid exceeds a set value, the relief valve 40c opens, causing the liquid to flow through the bypass line 32c and bypass the filter 22 downstream. This adjusts the pressure of the liquid to below the set value, protecting the filter 22.

[0017] 2, the relief valve 40 is fixed to a valve support member 34. The valve support member 34 is connected to a pipe 17 that constitutes the supply line 16 and a pipe 33 that constitutes the bypass line 32. The valve support member 34 has an inlet passage 36 and an outlet passage 38. The inlet passage 36 communicates with the supply line 16. The outlet passage 38 communicates with the bypass line 32. The outlet passage 38 may be annular and surround the relief valve 40.

[0018] The relief valve 40 includes a cylinder 42 , a valve body 44 , a spring member 46 , a spring receiving portion 48 , a holder 50 , and an adjustment member 52 .

[0019] As shown in FIG. 3 , the cylinder 42 is fixed to the valve support member 34 in a liquid-tight manner. The cylinder 42 is configured to be hollow and cylindrical. The cylinder 42 may have a cylindrical shape. The cylinder 42 has a peripheral wall portion 53, a cavity portion 54, an inlet 56, a seat portion 58, and an outlet 60. The peripheral wall portion 53 extends in the axial direction (X direction) of the cylinder 42. The peripheral wall portion 53 surrounds the cavity portion 54. The cavity portion 54 is formed within the peripheral wall portion 53. At least a portion of the peripheral wall portion 53 is disposed within the outlet passage 38 of the valve support member 34.

[0020] The inlet 56 is provided at one end of the peripheral wall portion 53. The inlet 56 communicates with the cavity portion 54. The inlet 56 axially penetrates one end of the cylinder 42. The inlet 56 opens at one end face 420 of the cylinder 42. The inlet 56 communicates with the inlet passage 36 of the valve support member 34. The shape of the inlet 56 when viewed in the axial direction may be circular. The diameter of the inlet 56 is smaller than the diameter of the cavity portion 54.

[0021] The receiving seat 58 surrounds the inlet 56 in the hollow portion 54. The receiving seat 58 is a stepped surface between an inner circumferential surface 421 of the cylinder 42 that surrounds the inlet 56 and an inner circumferential surface 422 that surrounds the hollow portion 54. The receiving seat 58 is annular and has its center on the axis Ax of the cylinder 42.

[0022] The outlet 60 can communicate with the inlet 56 via the cavity 54. The outlet 60 penetrates the peripheral wall 53 in the radial direction of the cylinder 42. The outlet 60 communicates with the outlet passage 38 of the valve support member 34. The outlet 60 is provided at a position spaced apart in the axial direction from the receiving seat 58. A plurality of outlets 60 are provided at intervals in the circumferential direction of the cylinder 42. Only one outlet 60 may be provided.

[0023] As shown in FIG. 5, the outlet 60 is formed with a first region R1, a second region R2, and a third region R3 in this order along the axial direction (X direction) in a direction (X1 direction) away from the receiving seat 58 (see FIG. 3). The first region R1, the second region R2, and the third region R3 are regions obtained by virtually dividing the outlet 60 into three equal parts in the axial direction. The first region R1, the second region R2, and the third region R3 are virtually divided regions and are not physically separated from one another. The first region R1, the second region R2, and the third region R3 collectively form a single outlet 60.

[0024] In the circumferential direction (P direction) of the cylinder 42, the opening width of the outflow port 60 gradually increases toward the X1 direction. In the circumferential direction of the cylinder 42, the opening width of the first region R1 is smaller than the opening width of the second region R2 and the opening width of the third region R3. In the circumferential direction of the cylinder 42, the opening width of the third region R3 is equal to or greater than the opening width of the second region R2. In FIG. 5 , the outflow port 60 is formed in a substantially triangular or trapezoidal shape when viewed from the radial direction of the cylinder 42. Therefore, the outflow port 60 has a pair of inclined portions 601 inclined with respect to the axis Ax of the cylinder 42. The shape of the outflow port 60 is not limited to a substantially triangular or trapezoidal shape. Therefore, the opening width of the second region R2 and the opening width of the third region R3 may be the same. The shape of the outflow port 60 may be another shape, such as a substantially circular or substantially rectangular shape.

[0025] 3, the valve body 44 is displaceable in the axial direction of the cylinder 42 within the cavity 54. The valve body 44 may have a hollow shape. The valve body 44 may have a cylindrical shape.

[0026] The valve body 44 has a head 62. The head 62 is provided with a seat 72 that faces the catch seat 58. As shown in FIG. 3, the seat 72 abuts against the catch seat 58 in the closed state. The valve body 44 is axially displaceable between the catch seat 58 of the cylinder 42 and one end surface 51 of the holder 50. That is, the stroke end on the valve closing side of the valve body 44 is determined by the catch seat 58. The stroke end on the valve opening side of the valve body 44 is determined by one end surface 51 of the holder 50.

[0027] As shown in FIG. 4 , the head 62 of the valve body 44 has a first surface 64, a second surface 66, a protrusion 68, and a communication passage 70. The first surface 64 may be circular. The first surface 64 is a portion of the head 62 of the valve body 44 that is located more inward than the protrusion 68. The second surface 66 may be annular along the circumferential direction of the valve body 44. The second surface 66 is the outer periphery of the head 62 of the valve body 44. A seat surface 72 is formed on the protruding end surface of the protrusion 68. The protrusion 68 extends along the circumferential direction of the valve body 44. The protrusion 68 may be an annular protrusion along the circumferential direction of the valve body 44.

[0028] 3, the first surface 64 faces the inlet 56 of the cylinder 42 in the axial direction. The second surface 66 faces the receiving seat 58 in the axial direction. The protrusion 68 protrudes from between the first surface 64 and the second surface 66 toward the receiving seat 58.

[0029] As shown in FIG. 4, the communicating passage 70 is provided in the convex portion 68. The communicating passage 70 communicates between the first surface 64 and the second surface 66. One end of the communicating passage 70 opens on the inner circumferential side of the annular convex portion 68. The other end of the communicating passage 70 opens on the outer circumferential side of the annular convex portion 68. The communicating passage 70 is a notched groove 71 provided in the convex portion 68. The communicating passage 70 is recessed relative to the seating surface 72. A plurality of communicating passages 70 are provided at intervals around the circumferential direction of the valve body 44. The plurality of communicating passages 70 divide the annular convex portion 68 into a plurality of arc-shaped ribs 68a.

[0030] 3, a clearance CL that allows liquid to flow is formed between the inner circumferential surface 530 of the peripheral wall portion 53 and the outer circumferential surface 440 of the valve body 44. The clearance CL is a minute gap formed by the difference between the inner diameter of the peripheral wall portion 53 (the diameter of the hollow portion 54) and the outer diameter of the valve body 44. In a valve-seated state where the seating surface 72 of the valve body 44 abuts against the receiving seat 58, the inlet 56 and the outlet 60 communicate with each other via the clearance CL.

[0031] The spring member 46 biases the valve body 44 toward the seat 58 of the cylinder 42. The spring member 46 extends along the axial direction of the cylinder 42. The spring member 46 may be a coil spring. One end of the spring member 46 may be inserted into the valve body 44.

[0032] As shown in FIG. 2, the spring receiving portion 48 supports the other end of the spring member 46. The spring receiving portion 48 is disposed in a hollow holder 50. The spring receiving portion 48 is displaceable in the axial direction within the holder 50. The spring receiving portion 48 is liquid-tight slidable along the inner circumferential surface of the holder 50. The holder 50 is fixed to the cylinder 42 in a liquid-tight manner. The holder 50 houses a portion of the spring member 46.

[0033] The adjustment member 52 adjusts the length (spring length) of the spring member 46 within the cylinder 42 and the holder 50. By adjusting the spring length, the valve opening pressure of the relief valve 40 can be adjusted. The adjustment member 52 is inserted into the holder 50. One end of the adjustment member 52 abuts against the spring receiving portion 48. The adjustment member 52 is a bolt. The adjustment member 52 is screwed into a nut 49 fixed to the holder 50. The length of the spring member 46 may be adjusted by setting the thickness (length) of the spring receiving portion 48 without providing the adjustment member 52.

[0034] The relief valve 40 configured as above operates as follows.

[0035] When the pressure of the liquid flowing through the supply line 16 is equal to or lower than a set value, the relief valve 40 remains in a closed state. That is, as shown in FIG. 3, the valve body 44 is in a valve-seated state in which the seating surface 72 abuts against the receiving seat 58. In the valve-seated state, the first surface 64 and the second surface 66 of the head 62 of the valve body 44 are in communication with each other via the communication passage 70. Therefore, in the valve-seated state, fluid pressure acts not only on the first surface 64 but also on the second surface 66. That is, in the valve-seated state, not only the first surface 64 but also the second surface 66 is a pressure-receiving surface.

[0036] Furthermore, in the valve seated state, a clearance CL is formed between the inner circumferential surface 530 of the peripheral wall portion 53 and the outer circumferential surface 440 of the valve body 44. Therefore, liquid that reaches the second surface 66 flows through the clearance CL and flows out through the outlet 60. That is, in the valve seated state, the space between the cylinder 42 and the valve body 44 is not liquid-tight, and a small amount of liquid leaks from the outlet 60 via the minute clearance CL. In this case, the area where the portion of the inner circumferential surface 530 of the peripheral wall portion 53 between the seat portion 58 and the outlet 60 overlaps with the outer circumferential surface 440 of the valve body 44 is a leak path LP for liquid. The length of the leak path LP along the axial direction is maximum in the valve seated state. Therefore, in the valve seated state, the fluid resistance due to the leak path LP is maximum, and the amount of leakage is minimum.

[0037] When the pressure of the liquid flowing through the supply line 16 exceeds a set value, the valve body 44 begins to displace in the axial direction (X1 direction). This set value is the cracking pressure at which the relief valve 40 opens. As the valve body 44 begins to displace, the seating surface 72 of the valve body 44 separates from the receiving seat 58. As this separation occurs, the seating surface 72 also becomes a pressure-receiving surface, in addition to the first surface 64 and the second surface 66. Therefore, the area of ​​the seating surface 72 is the difference in the pressure-receiving area before and after the seating surface 72 of the valve body 44 separates from the receiving seat 58. Note that when the valve body 44 displaces in the axial direction, liquid is discharged from the space 424 in which the spring member 46 is located within the cylinder 42 to the outflow path 38 via the hole 43 provided in the cylinder 42. This allows the displacement of the valve body 44 to continue unimpeded.

[0038] As the pressure of the liquid flowing through the supply line 16 increases, the valve body 44 begins to displace. As the valve body 44 displaces, the pressure-receiving surface consisting of the first surface 64, the second surface 66, and the seating surface 72 increases, and the pressure (the product of the load of the spring member 46 and the pressure-receiving area) pushing the valve body 44 back toward the seating surface decreases. This increases the amount of displacement of the valve body 44. As the amount of displacement of the valve body 44 increases, the load of the spring member 46 increases, generating pressure in a direction pushing the valve body 44 toward the pressure-receiving surface. The valve body 44 moves to an equilibrium position where this upward pressure is balanced with the pressure of the liquid flowing through the supply line 16. This increases the amount of liquid flowing through the bypass lines 32a, 32b, 32b (see Figure 1), allowing the pressure of the liquid flowing through the supply line 16 to be kept below a set value. Even if the pressure of the liquid flowing through the supply line 16 changes, this can be accommodated by changing the equilibrium position of the valve body 44, making it possible to accommodate various pressure increases that exceed the set value of the liquid flowing through the supply line 16.

[0039] This embodiment has the following advantages.

[0040] The protrusion 68 and the communication passage 70 provided on the head 62 of the valve body 44 reduce the difference in pressure-receiving area before and after the valve is opened. This reduces pressure fluctuations (pressure pulsations) before and after the valve is opened, stabilizing valve behavior. In other words, hunting or chattering can be suppressed. The reduction in pressure fluctuations before and after the valve is opened eliminates the need to increase the performance of the supply pump 18, motor, and other components in the fluid circuit 12 in which the relief valve 40 is installed in FIG. 1. Furthermore, the reduction in pressure fluctuations before and after the valve is opened allows the pressure resistance of the fluid circuit 12 to be kept to a minimum. This allows the fluid circuit 12 (liquid supply device 13) to be made lighter and more compact.

[0041] As shown in Figure 4, the protrusion 68 extends along the circumferential direction of the valve body 44. This configuration stabilizes the valve seating state. The protrusion 68 has a rib structure, which makes it easy to ensure the area of ​​the seating surface 72, and therefore makes it easy to improve buckling resistance. The communicating passage 70 is a notched groove 71 provided in the protrusion 68, so the communicating passage 70 can be easily formed.

[0042] As shown in Figure 3, when the seating surface 72 of the valve body 44 abuts against the receiving seat 58, the inlet 56 and the outlet 60 communicate with each other via a clearance CL. With this configuration, there is a certain amount of leakage when the valve is in a seated state, which reduces the change in flow rate before and after the valve is opened. The pressure fluctuation caused by the change in pressure-receiving area and the pressure fluctuation caused by the outlet 60 being opened are not synchronized, which effectively reduces the pressure fluctuation. Because the outlet 60 is located axially away from the receiving seat 58, the fluid resistance at the clearance CL increases, which reduces the amount of leakage when the valve is in a seated state to the minimum necessary.

[0043] As shown in FIG. 5, the outflow port 60 is formed with a first region R1, a second region R2, and a third region R3 in this order along the axial direction (the X1 direction) away from the receiving seat 58 (FIG. 3). In the circumferential direction of the cylinder 42, the opening width of the first region R1 is smaller than the opening widths of the second region R2 and the third region R3. The opening width of the third region R3 is equal to or greater than the opening width of the second region R2. This configuration allows the opening area of ​​the outflow port 60 to be reduced when it is initially open. In FIG. 3, the opening area of ​​the outflow port 60 can be increased as the movement of the valve body 44 increases. Furthermore, sudden pressure fluctuations during movement of the valve body 44 can be effectively suppressed.

[0044] The following additional notes are further disclosed regarding the above embodiment.

[0045] (Note 1) A relief valve (40) of the present disclosure includes a cylinder (42) having a peripheral wall (53), a cavity (54) formed in the peripheral wall, an inlet (56) provided at one end of the peripheral wall and communicating with the cavity, a receiving seat (58) surrounding the inlet in the cavity, and an outlet (60) capable of communicating with the inlet via the cavity, and a head (62) displaceable in the axial direction of the cylinder within the cavity and provided with a seat (72) facing the receiving seat, and in a closed state, the seat The relief valve includes a valve body (44) that abuts against the seat and a spring member (46) that biases the valve body toward the seat of the cylinder, and the head has a first surface (64) that faces the inlet in the axial direction, a second surface (66) that faces the seat in the axial direction, a convex portion (68) that protrudes toward the seat from between the first surface and the second surface and on which the seat surface is formed, and a communication passage (70) that is provided in the convex portion and that connects the first surface and the second surface.

[0046] (Supplementary Note 2) In the relief valve according to Supplementary Note 1, the convex portion may extend along the circumferential direction of the valve body, and the communication passage may be a notched groove (71) provided in the convex portion.

[0047] (Supplementary Note 3) In the relief valve according to Supplementary Note 2, the convex portion may be an annular projection, and a plurality of the notched grooves may be provided at intervals in the circumferential direction.

[0048] (Appendix 4) In the relief valve described in Appendix 1, the outlet is provided at a position spaced apart from the seat in the axial direction, and a clearance (CL) that allows liquid flow is formed between the inner surface (530) of the peripheral wall and the outer surface (440) of the valve body, and the inlet and outlet may be connected via the clearance when the valve is in a seated state with the seat surface of the valve body abutting against the seat.

[0049] (Supplementary Note 5) In the relief valve according to any one of Supplementary Notes 1 to 4, the outlet may be formed with a first region (R1), a second region (R2), and a third region (R3) in this order along the axial direction in a direction away from the seat portion, and in the circumferential direction of the cylinder, the opening width of the first region may be smaller than the opening width of the second region and the opening width of the third region, and the opening width of the third region may be equal to or larger than the opening width of the second region.

[0050] (Supplementary Note 6) In the relief valve according to Supplementary Note 5, the outlet may be formed in a substantially triangular or trapezoidal shape when viewed in a radial direction of the cylinder.

[0051] Although the present disclosure has been described in detail, the present disclosure is not limited to the individual embodiments described above. Various additions, substitutions, modifications, partial deletions, etc. are possible in these embodiments without departing from the gist of the present disclosure or the spirit of the present disclosure derived from the content of the claims and their equivalents. These embodiments can also be implemented in combination. For example, in the above-described embodiments, the order of each operation and the order of each process are shown as examples and are not limited to these. The same applies when numerical values ​​or mathematical expressions are used in the description of the above-described embodiments. [Explanation of symbols]

[0052] 40...Relief valve 42...Cylinder 44... Valve body 46... Spring member 53...Peripheral wall part 54...Cavity part 56...Inlet 58...Socket part 60…Outlet 62…Head 64...Side 1 66...Side 2 68...Protrusion 70...Communicating passage 72...Seat

Claims

1. a cylinder having a peripheral wall portion, a cavity portion formed within the peripheral wall portion, an inlet port provided at one end of the peripheral wall portion and communicating with the cavity portion, a seat portion in the cavity portion surrounding the inlet port, and an outlet port capable of communicating with the inlet port via the cavity portion; a valve body that is displaceable in the axial direction of the cylinder within the hollow portion, the valve body having a head portion with a seat surface facing the seat portion, the seat surface abutting against the seat portion in a valve closed state; a spring member that biases the valve body toward the receiving seat of the cylinder; A relief valve comprising: The head portion a first surface facing the inlet in the axial direction; a second surface facing the receiving seat in the axial direction; a protrusion that protrudes from between the first surface and the second surface toward the receiving seat and on which the seat surface is formed; a communication passage provided in the convex portion, the communication passage connecting the first surface and the second surface.

2. 2. The relief valve according to claim 1, The protrusion extends along the circumferential direction of the valve body, the communication passage is a notched groove provided in the protrusion.

3. 3. The relief valve according to claim 2, the protrusion is an annular projection, A relief valve, wherein a plurality of the notched grooves are provided at intervals in the circumferential direction.

4. 2. The relief valve according to claim 1, The outlet is provided at a position spaced apart from the receiving seat in the axial direction, a clearance that allows liquid to flow is formed between the inner circumferential surface of the peripheral wall portion and the outer circumferential surface of the valve body, a relief valve in which, in a valve seated state in which the seat surface of the valve body abuts against the receiving seat, the inlet and the outlet communicate with each other via the clearance.

5. The relief valve according to any one of claims 1 to 4, The outlet has a first region, a second region, and a third region formed in this order in a direction away from the seat portion along the axial direction, a relief valve in which, in a circumferential direction of the cylinder, an opening width of the first region is smaller than an opening width of the second region and an opening width of the third region, and the opening width of the third region is equal to or larger than the opening width of the second region.

6. 6. The relief valve according to claim 5, A relief valve, wherein the outlet is formed in a substantially triangular or trapezoidal shape when viewed from a radial direction of the cylinder.

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