Pressure reduction valve

Abstract

A pressure reduction valve (1) has: a body (11) with a gas flow path; a valve seat (14); a valve body (17); a piston (16), and a biasing member (18). The valve body has a shaft section (17A) and a valve section (17B). The gas flow path has a primary chamber (31), a secondary chamber (32), and an atmospheric chamber (33). The primary chamber and the secondary chamber are partitioned by the valve seat (14). The primary chamber and the atmospheric chamber are partitioned by a divider wall (21). The secondary chamber and the atmospheric chamber are partitioned by a piston. The body has a primary port (2) and a secondary port (3). The primary chamber is a region in which the valve part is disposed, and is a region extending from the primary port to the valve seat. The secondary chamber is a region extending from the valve seat to the secondary port. The atmospheric chamber is a region in which the biasing member is disposed and is open to the atmosphere. The shaft part penetrates the divider wall so as to be slidable in the axial direction and is connected to the valve part.

Description

Pressure reducing valve

[0001] The present disclosure relates to a pressure reducing valve.

[0002] Conventionally, there are pressure reducing valves that reduce the pressure of gas supplied from a primary port and deliver the reduced pressure gas to a secondary port. For example, the pressure reducing valve disclosed in Patent Document 1 includes a housing, a valve seat, a valve body, a first spring, a piston, and a second spring.

[0003] The housing has a body and a cover. The body has a primary pressure chamber. The seat is annular and is provided at the boundary between the cover and the body. The valve is a shaft-shaped body having a shaft portion extending in the axial direction and a valve body portion having a diameter larger than that of the shaft portion. A first end of the shaft portion is supported on the body so as to be slidable in the axial direction. A second end of the shaft portion passes through the seat in the axial direction without contact and is located inside the cover. The valve body portion is accommodated in the primary pressure chamber. The outer peripheral surface of the valve body portion has a tapered surface. The tapered surface is capable of moving axially toward and away from the inner peripheral surface of the seat. A first spring constantly urges the valve body portion in a direction toward the seat.

[0004] The piston is a hollow cylindrical body housed inside the cover. The outer peripheral surface of the piston is axially slidable relative to the inner peripheral surface of the cover. The interior of the cover is divided by the piston into an atmospheric pressure chamber and a secondary pressure chamber. The second end of the valve is located inside the secondary pressure chamber.

[0005] A second spring constantly biases the piston toward the second end of the valve. Movement of the piston toward the second end of the valve is restricted by the surface of the piston opposite the atmospheric pressure chamber abutting axially against the second end of the valve. While abutting against the second end of the valve, the piston moves integrally with the valve.

[0006] The valve is pushed axially by the piston, causing the valve body to separate from the seat, thereby communicating between the primary pressure chamber and the secondary pressure chamber. At this time, the pressure reducing valve is in an open state. Furthermore, the valve is blocked from communication between the primary pressure chamber and the secondary pressure chamber by the valve body abutting against the seat. At this time, the pressure reducing valve is in a closed state. The valve moves in response to the pressure difference between the primary pressure chamber and the secondary pressure chamber and the biasing forces of the first spring and the second spring. The secondary pressure is adjusted by changing the opening of the pressure reducing valve in response to the position of the valve body.

[0007] Japanese Patent Application Laid-Open No. 2018-156259

[0008] The pressure reducing valve is required to be small in size in order to improve the mountability, for example.

[0009] A pressure reducing valve according to one aspect of the present disclosure includes a body having a gas flow path, a valve seat provided midway through the gas flow path, the valve seat having a valve hole axially penetrating the valve seat, a valve element configured to open and close the valve seat, a piston connected to the valve element, and a biasing member configured to constantly bias the piston in a valve opening direction. The valve element has a shaft connected to the piston and a valve portion provided at the end of the shaft and configured to open and close the valve seat. The gas flow path includes a primary chamber, a secondary chamber, and an atmospheric chamber. The primary chamber and the secondary chamber are separated by the valve seat. The primary chamber and the atmospheric chamber are separated by a partition wall extending in a direction perpendicular to the axial direction of the body. The secondary chamber and the atmospheric chamber are separated by the piston. The body includes a primary port configured to introduce gas from the outside into the primary chamber and a secondary port configured to discharge gas in the secondary chamber to the outside. The primary chamber is a region in which the valve portion is disposed and is a region from the primary port to the valve seat. The secondary chamber is a region from the valve seat to the secondary port. The atmospheric chamber is a region in which the biasing member is disposed and is open to the atmosphere. The shaft portion slidably penetrates the partition wall in the axial direction and is connected to the valve portion.

[0010] Fig. 1 is a cross-sectional view of a pressure reducing valve according to a first embodiment, taken along the axial direction. Fig. 2 is a graph showing the relationship between primary pressure and secondary pressure of the pressure reducing valve of Fig. 1. Fig. 3 is a cross-sectional view of a pressure reducing valve according to a second embodiment, taken along the axial direction. Fig. 4 is a cross-sectional view of a pressure reducing valve according to a third embodiment, taken along the axial direction. Fig. 5 is a cross-sectional view of a pressure reducing valve according to a fourth embodiment, taken along the axial direction. Fig. 6 is a cross-sectional view of a pressure reducing valve according to a fifth embodiment, taken along the axial direction. Fig. 7 is a cross-sectional view of a pressure reducing valve according to a sixth embodiment, taken along the axial direction.

[0011] <First embodiment> A pressure reducing valve 1 according to a first embodiment will be described. As shown in Fig. 1 , the pressure reducing valve 1 is provided, for example, in a fluid circuit connecting a hydrogen gas tank mounted on a fuel cell vehicle to a fuel cell. The pressure reducing valve 1 reduces the primary pressure, which is the pressure of hydrogen gas supplied from the gas tank via a primary port 2, to a pressure equal to or lower than a set pressure, and supplies the reduced pressure gas to the fuel cell via a secondary port 3. The primary pressure of the gas supplied from the primary port 2 is a high pressure, for example, about 87.5 MPa. The set pressure is a target value of the secondary pressure, which is the pressure reduced by the pressure reducing valve 1, and is, for example, about 1.2 MPa.

[0012] As shown in FIG. 1 , the pressure reducing valve 1 has a body 11, a coupling member 12, and a relief valve 13. The body 11 is a metallic cylindrical body having a circular cross-sectional shape. The body 11 has a primary port 2. The primary port 2 penetrates the peripheral wall of the body 11 in the radial direction. The coupling member 12 is made of metal and is attached to a first end of the body 11. The coupling member 12 is a cylindrical body having a circular cross-sectional shape and has a secondary port 3. The secondary port 3 penetrates the coupling member 12 in the axial direction. The relief valve 13 is attached to a second end of the body 11. The second end is an end opposite to the first end of the body 11.

[0013] The body 11 has a partition wall 21. The partition wall 21 extends in the radial direction of the body 11. The radial direction is a direction perpendicular to the axial direction of the body 11. The partition wall 21 divides the interior of the body 11 into two accommodating sections. The first accommodating section 11A is an accommodating section on the first end side of the body 11 with respect to the partition wall 21, i.e., on the coupling member 12 side. The second accommodating section 11B is an accommodating section on the relief valve 13 side with respect to the partition wall 21. The partition wall 21 has a valve element support hole 21A. The valve element support hole 21A penetrates the partition wall 21 in the axial direction of the body 11.

[0014] The body 11 has a valve seat mounting portion 22 and a retaining member mounting portion 23. The valve seat mounting portion 22 and the retaining member mounting portion 23 are provided on the inner circumferential surface of the second accommodating portion 11B. The valve seat mounting portion 22 has an annular first end face that extends in the radial direction of the body 11. The retaining member mounting portion 23 is located on the opposite side of the partition wall 21 from the valve seat mounting portion 22. The inner diameter of the retaining member mounting portion 23 is larger than the inner diameter of the valve seat mounting portion 22. The retaining member mounting portion 23 has an annular second end face that extends in the radial direction of the body 11. An internal thread is provided on the inner circumferential surface of the retaining member mounting portion 23. In other words, the retaining member mounting portion 23 is a screw hole.

[0015] The body 11 has a communication passage 24. The communication passage 24 connects the first accommodating portion 11A and the second accommodating portion 11B. The communication passage 24 has a first radial passage, a second radial passage, and an axial passage. The first radial passage extends radially outward from the first accommodating portion 11A. The second radial passage extends radially outward from the second accommodating portion 11B. The axial passage is disposed radially outward from the first accommodating portion 11A and the second accommodating portion 11B. The axial passage connects the first radial passage and the second radial passage.

[0016] The body 11 has an atmosphere communication hole 25. The atmosphere communication hole 25 connects the interior of the first housing portion 11A of the body 11 with the exterior of the body 11. The pressure reducing valve 1 has a valve seat 14. The valve seat 14 is an annular body made of resin. The valve seat 14 is attached to a valve seat mounting portion 22 of the second housing portion 11B of the body. The valve seat 14 has a valve hole 14A. The valve hole 14A passes through the valve seat 14 in the axial direction. The valve hole 14A is arranged coaxially with the valve element support hole 21A of the partition wall 21. The valve hole 14A has a first tapered surface 14B. The first tapered surface 14B is provided in a region of the valve hole 14A closer to the partition wall 21. The first tapered surface 14B is inclined so that the inner diameter increases toward the partition wall 21.

[0017] The pressure reducing valve 1 has a retaining member 15. The retaining member 15 is a metallic cylindrical body having a circular cross-sectional shape. The retaining member 15 is attached to a retaining member mounting portion 23 of the second housing portion 11B of the body. A male thread is provided on the outer peripheral surface of the retaining member 15. The retaining member 15 is attached to the body 11 by being screwed into the inner periphery of the retaining member mounting portion 23 of the body 11. The retaining member 15 has a flow hole 15A. The flow hole 15A passes through the retaining member 15 in the axial direction. The flow hole 15A is arranged coaxially with the valve hole 14A of the valve seat 14. The retaining member 15 maintains the valve seat 14 pressed against a first end face, which is the axial end face of the valve seat mounting portion 22.

[0018] The pressure reducing valve 1 has a piston 16. The piston 16 is a two-stage cylindrical body having a circular cross section, and is housed in a first housing portion 11A of the body 11. The piston 16 is made of, for example, metal, and has a pressure-receiving portion 16A and a valve element support portion 16B.

[0019] The outer diameter of the pressure-receiving portion 16A is approximately the same as or slightly smaller than the inner diameter of the first housing portion 11A of the body 11. The outer peripheral surface of the pressure-receiving portion 16A is axially slidable relative to the inner peripheral surface of the first housing portion 11A of the body 11.

[0020] A groove having a rectangular cross section is provided around the entire outer periphery of the pressure-receiving portion 16A. A first seal member 16C is attached to the groove. The first seal member 16C is, for example, an annular body made of rubber. The first seal member 16C may be, for example, a packing having a Y-shaped cross section. The first seal member 16C ensures airtightness between the outer periphery of the pressure-receiving portion 16A and the inner periphery of the first housing portion 11A of the body 11.

[0021] The valve element support portion 16B is provided on the surface of the pressure receiving portion 16A that faces the partition wall 21 in the axial direction. The outer diameter of the valve element support portion 16B is smaller than the outer diameter of the pressure receiving portion 16A. The tip of the valve element support portion 16B is spaced apart from the partition wall 21 in the axial direction. The tip is the end of the valve element support portion 16B opposite to the pressure receiving portion 16A.

[0022] The valve disc support portion 16B has a valve disc support hole 16D. The valve disc support hole 16D is a blind hole that extends in the axial direction of the piston 16. The valve disc support hole 16D opens at the tip of the valve disc support portion 16B. The valve disc support hole 16D is arranged coaxially with the valve disc support hole 21A in the partition wall 21. The inner diameter of the valve disc support hole 16D is approximately the same as the inner diameter of the valve disc support hole 21A in the partition wall 21.

[0023] The pressure reducing valve 1 has a valve element 17. The valve element 17 is made of, for example, metal and has a shaft portion 17A and a valve portion 17B. The shaft portion 17A is a columnar body with a circular cross-sectional shape. A first end of the shaft portion 17A is fitted into a valve element support hole 16D of the piston 16. The shaft portion 17A moves integrally with the piston 16. The shaft portion 17A may be fixed to the piston 16 by, for example, a bolt. A second end of the shaft portion 17A axially passes through a valve element support hole 21A of the partition wall 21 and is located inside the second housing portion 11B of the body 11. The second end is the end opposite the first end of the shaft portion 17A. The outer peripheral surface of the shaft portion 17A is axially slidable relative to the inner peripheral surface of the valve element support hole 21A.

[0024] A groove having a rectangular cross section is provided around the entire circumference of the outer peripheral surface of the portion of the shaft portion 17A that corresponds to the valve disc support hole 21A. A second seal member 17C is attached to the groove. The second seal member 17C is, for example, an annular body made of rubber. The second seal member 17C may be, for example, a packing having a Y-shaped cross section. The second seal member 17C ensures airtightness between the outer peripheral surface of the portion of the shaft portion 17A that corresponds to the valve disc support hole 21A and the inner peripheral surface of the valve disc support hole 21A.

[0025] The valve portion 17B is provided at the second end of the shaft portion 17A. The valve portion 17B is located inside the second housing portion 11B of the body 11. The valve portion 17B is a columnar body with a circular cross-sectional shape. The outer diameter of the valve portion 17B is larger than the outer diameter of the shaft portion 17A. The valve portion 17B has a second tapered surface 17D. The second tapered surface 17D is provided on the outer peripheral surface of the tip of the valve portion 17B. The tip is the end of the valve portion 17B opposite the shaft portion 17A. The second tapered surface 17D is inclined so that the outer diameter decreases toward the tip of the valve portion 17B. The inclination of the second tapered surface 17D corresponds to the inclination of the first tapered surface 14B of the valve seat 14. The second tapered surface 17D is movable toward and away from the first tapered surface 14B in the axial direction.

[0026] The pressure reducing valve 1 has a biasing member 18. The biasing member 18 is, for example, a compression coil spring, and is housed in the first housing portion 11A of the body 11. The biasing member 18 is interposed between the pressure-receiving portion 16A of the piston 16 and the partition wall 21. The biasing member 18 constantly biases the piston 16 in a direction moving the piston 16 away from the partition wall 21 in the axial direction. In other words, the biasing member 18 constantly biases the valve body 17, via the piston 16, in a direction moving the valve portion 17B away from the valve seat 14 in the axial direction.

[0027] The pressure reducing valve 1 has a primary chamber 31, a secondary chamber 32, and an atmospheric chamber 33. The primary chamber 31, the secondary chamber 32, and the atmospheric chamber 33 form a gas flow path through which hydrogen gas flows. The primary chamber 31 is a region of the internal space of the body 11 in which the valve portion 17B is disposed, and is the region from the primary port 2 to the valve seat 14. The primary chamber 31 is an internal space of the body 11 surrounded by the partition wall 21, the peripheral wall of the body 11, and the valve seat 14.

[0028] The secondary chamber 32 is a region of the internal space of the body 11 extending from the valve seat 14 to the secondary port 3. The secondary chamber 32 has a first internal space 32A, a second internal space 32B, and a third internal space 32C. The first internal space 32A is an internal space of the body 11 surrounded by the valve seat 14, the peripheral wall of the body 11, and the relief valve 13. The second internal space 32B is an internal space of the body 11 surrounded by the pressure-receiving portion 16A, the peripheral wall of the body 11, and the coupling member 12. The third internal space 32C is an internal space of the communicating passage 24, and is an internal space of the body 11 that communicates between the first internal space 32A and the second internal space 32B.

[0029] The atmospheric chamber 33 is a region of the internal space of the body 11 in which the biasing member 18 is disposed. The atmospheric chamber 33 is open to the atmosphere via the atmosphere communication hole 25. The atmospheric chamber 33 is an internal space of the body 11 surrounded by the partition wall 21, the peripheral wall of the body 11, and the pressure-receiving portion 16A. The atmospheric chamber 33 and the primary chamber 31 are separated by the partition wall 21. The atmospheric chamber 33 and the secondary chamber 32 are separated by the pressure-receiving portion 16A.

[0030] <Operation of Pressure Reducing Valve 1> Next, the operation of the pressure reducing valve 1 will be described. In the initial state before high-pressure hydrogen gas is supplied from the primary port 2, the pressure reducing valve 1 is in an open state. That is, the valve element 17 is maintained in an open position by the biasing force of the biasing member 18. The open position is a position of the valve element 17 where the valve portion 17B is spaced axially away from the valve seat 14.

[0031] When hydrogen gas at primary pressure is supplied from primary port 2, the hydrogen gas passes through primary chamber 31 and flows into secondary chamber 32 through the gap between valve hole 14A and valve portion 17B. The gap between valve hole 14A and valve portion 17B is the gap between first tapered surface 14B and second tapered surface 17D. As the hydrogen gas passes through the gap between valve hole 14A and valve portion 17B, its pressure is reduced in accordance with the size of the gap.

[0032] The secondary chamber 32 includes a first internal space 32A, a second internal space 32B, and a third internal space 32C. The reduced-pressure hydrogen gas flows from the first internal space 32A through the second internal space 32B to the third internal space 32C and is then discharged from the secondary port 3. As the amount of hydrogen gas flowing in through the valve hole 14A increases, the secondary pressure increases. The secondary pressure is the pressure of the hydrogen gas in the secondary chamber 32.

[0033] As the secondary pressure increases, the piston 16 moves axially toward the partition wall 21 against the biasing force of the biasing member 18. The valve element 17 moves integrally with the piston 16 in the valve closing direction. The valve closing direction is the direction in which the valve portion 17B abuts against the valve seat 14 in the axial direction of the body 11. As the secondary pressure increases, the valve element 17 eventually reaches the valve closed position. The valve closed position is a position of the valve element 17 where the valve portion 17B abuts against the valve seat 14 in the axial direction. The valve portion 17B abuts against the valve seat 14 when, for example, the secondary pressure reaches a set pressure. When the valve element 17 is in the valve closed position, the pressure reducing valve 1 is in a closed state.

[0034] Thereafter, when the secondary pressure decreases as hydrogen gas is consumed in the fuel cell, the valve element 17 moves integrally with the piston 16 in the valve opening direction in response to the decrease in secondary pressure. The valve opening direction is the opposite direction to the valve closing direction, and is the direction in which the valve portion 17B moves away from the valve seat 14 in the axial direction of the body 11. When the valve element 17 reaches the valve opening position, hydrogen gas again flows in from the primary port 2. This causes the secondary pressure to rise again. As the secondary pressure rises, the valve element 17 moves integrally with the piston 16 in the valve closing direction and eventually reaches the valve closing position.

[0035] In this way, the pressure reducing valve 1 can reduce the pressure of high-pressure hydrogen gas to a desired set pressure by moving the valve element 17 between the open and closed positions in accordance with the pressure difference between the primary and secondary pressures. The hydrogen gas adjusted to the set pressure is supplied to the fuel cell.

[0036] If the secondary pressure reaches an excessive pressure exceeding the set value set in the relief valve 13, the relief valve 13 automatically releases the pressure in the secondary chamber 32 to the outside. <Operation of Pressure Reducing Valve 1> Next, the operation of the pressure reducing valve 1 will be described.

[0037] The piston 16 is fixed to the end of the valve element 17 opposite the valve portion 17B. The shaft portion 17A of the valve element 17 axially penetrates the partition wall 21, and the valve portion 17B is located inside the primary chamber 31. An atmospheric chamber 33 is provided between the piston 16 and the partition wall 21. The secondary chamber 32 has a first internal space 32A, a second internal space 32B, and a third internal space 32C. The first internal space 32A is located on the opposite side of the valve element 17 with respect to the valve seat 14. The second internal space 32B is located on the opposite side of the valve element 17 with respect to the piston 16. The third internal space 32C communicates between the first internal space 32A and the second internal space 32B. Therefore, secondary pressure is applied to the surface of the piston 16 opposite the valve element 17.

[0038] By adopting this configuration, unlike when the piston 16 is disposed in the first internal space 32A, for example, it is not necessary to pass the shaft member connecting the piston 16 and the valve body 17 through the valve hole 14A. This makes it possible to reduce the inner diameter and therefore the cross-sectional area of ​​the valve hole 14A. Since the area of ​​the valve hole 14A that receives the primary pressure on the valve body 17 is reduced by the amount of the reduced cross-sectional area, it is possible to reduce the outer diameter and therefore the cross-sectional area of ​​the piston 16. This makes it possible to reduce the size of the pressure reducing valve 1, particularly in the radial direction. Furthermore, it is possible to reduce the production cost of the pressure reducing valve 1.

[0039] In addition, the secondary pressure P Ｌ is expressed by the following equation 1.

[0040]

[0041] However, as shown in Figure 1, Ｈ " is the primary pressure. ａｔｍ " is atmospheric pressure. １ " is the cross-sectional area of ​​the valve hole 14A. １ is the area of ​​a cross section of the valve hole 14A where the first tapered surface 14B is not provided, taken along a plane perpendicular to the axial direction of the body 11. １ is the primary pressure P of the valve body 17 Ｈ , that is, the area of ​​the tip surface of the valve portion 17B exposed inside the valve hole 14A.

[0042] Incidentally, the first tapered surface 14B may be composed of a plurality of tapered surfaces with different inclinations. In this case, the second tapered surface 17D of the valve portion 17B abuts, for example, in the axial direction against a portion of the first tapered surface 14B that corresponds to the inclination of the second tapered surface 17D. In this case, the cross-sectional area S １ is the cross-sectional area of ​​the valve hole 14A at the position where the second tapered surface 17D abuts in the axial direction.

[0043] "S ２ " is the cross-sectional area of ​​the shaft portion 17A of the valve body 17. It is the area of ​​the cross section when the shaft portion 17A is cut along a plane perpendicular to the axial direction of the body 11. "S ３ " is the cross-sectional area of ​​the piston 16. Cross-sectional area S ３ is the area of ​​the cross section when the pressure receiving portion 16A of the piston 16 is cut by a plane perpendicular to the axial direction of the body 11. When the outer diameter of the pressure receiving portion 16A is approximately the same as the inner diameter of the first housing portion 11A of the body 11, the cross section area S ３ The outer diameter of the pressure receiving portion 16A is the maximum diameter of the piston 16.

[0044] Incidentally, when the outer diameter of the pressure receiving portion 16A is slightly smaller than the inner diameter of the first accommodating portion 11A, the first seal member 16C protrudes radially outward from the outer circumferential surface of the pressure receiving portion 16A and contacts the inner circumferential surface of the first accommodating portion 11A so as to be slidable in the axial direction. ３ is the sum of the cross-sectional area of ​​the pressure-receiving portion 16A and the cross-sectional area of ​​the portion of the first seal member 16C that protrudes radially outward from the outer circumferential surface of the pressure-receiving portion 16A.

[0045] "F Ｓ " is the contact load between the valve portion 17B of the valve body 17 and the valve seat 14. Ｋ " is the load generated by the biasing member 18. μ１ " is the sliding resistance of the shaft portion 17A of the valve body 17. μ２ " is the sliding resistance of the pressure receiving portion 16A of the piston 16.

[0046] In addition, "F" in FIG. ＰＬ１ " is the secondary pressure P of the valve body 17 Ｌ This is the pressure load due to "F ＰＬ２ " is the secondary pressure P of the piston 16 Ｌ This is the pressure load due to "F ＰＨ１ " is the primary pressure P of the valve body 17 Ｈ This is the pressure load due to "F ａｔｍ１ " is the atmospheric pressure P of the valve body 17 ａｔｍ This is the pressure load due to "F ａｔｍ２ ” is the atmospheric pressure P of the piston 16 ａｔｍ This is the pressure load applied by the

[0047] From Equation 1, by reducing the value of the coefficient of the first term on the right side of Equation 1, the primary pressure P Ｈ Changes in secondary pressure P Ｌ It can be seen that the fluctuation of can be suppressed. The coefficient is "(S ２ -S １ ) / (S ３ -S １ )." " / " represents division.

[0048] Therefore, the cross-sectional area S of the valve hole 14A １ and the cross-sectional area S of the shaft portion 17A of the valve body 17. ２ and the same level (S １ ≒S ２ ) so that the cross-sectional area S of the piston 16 ３ Without increasing the primary pressure P Ｈ Changes in secondary pressure P Ｌ For example, the fluctuation of the primary pressure P Ｈ Even if the primary pressure P Ｈ Changes in secondary pressure PＬ fluctuations can be suppressed.

[0049] As shown in FIG. 2, for example, the cross-sectional area S １ and the cross-sectional area S of the shaft portion 17A of the valve body 17. ２ The same as (S １ = S ２ ), the secondary pressure P Ｌ is the primary pressure P Ｈ However, the sliding resistance F of the shaft portion 17A of the valve body 17 is maintained at a constant value. μ１ and the sliding resistance F of the pressure receiving portion 16A of the piston 16. μ２ are assumed to be constant.

[0050] The cross-sectional area S of the valve hole 14A １ and the cross-sectional area S of the shaft portion 17A ２ The cross-sectional area S of the valve hole 14A may not be the same. １ and the cross-sectional area S of the shaft portion 17A ２ The primary pressure P Ｈ Changes in secondary pressure P Ｌ The variation of the cross-sectional area S of the valve hole 14A may be set to fall within a tolerance range. The tolerance range is determined, for example, by product specifications. １ is the cross-sectional area S of the shaft portion 17A ２ This is because the cross-sectional area S １ is the cross-sectional area S of the shaft portion 17A ２ If the primary pressure P Ｈ The valve element 17 is pushed in the valve opening direction by the cross-sectional area S of the valve hole 14A, which may result in a decrease in responsiveness when the valve is closed. １ is the cross-sectional area S of the shaft portion 17A ２ If the primary pressure P Ｈ That is, the primary pressure P Ｈ Pressure load F ＰＨ１ The cross-sectional area S of the valve hole 14A is "0". １ is the cross-sectional area S of the shaft portion 17A ２ If it exceeds the primary pressure P Ｈ Since the valve element 17 is pushed in the valve closing direction by the force, response when the valve is closed can be ensured.

[0051] <Advantages of the First Embodiment> The first embodiment has the following advantages. (1-1) The valve includes a body 11 having a gas flow path, a valve seat 14 provided midway through the gas flow path, a valve element 17 that opens and closes the valve seat 14 in the gas flow path, a piston 16 connected to the valve element 17, and a biasing member 18 that constantly biases the piston 16 in a valve-opening direction. The valve-opening direction is the direction in which the valve element 17 moves away from the valve seat 14. The valve seat 14 has a valve hole 14A that penetrates the body 11 in the axial direction.

[0052] The valve element 17 has a shaft portion 17A connected to the piston 16, and a valve portion 17B provided at the end of the shaft portion 17A for opening and closing the valve seat 14. The gas flow path has a primary chamber 31, a secondary chamber 32, and an atmospheric chamber 33. The primary chamber 31 and the secondary chamber 32 are separated by the valve seat 14. The primary chamber 31 and the atmospheric chamber 33 are separated by a partition wall 21 that extends in the radial direction of the body 11. The radial direction is a direction perpendicular to the axial direction of the body 11. The secondary chamber 32 and the atmospheric chamber 33 are separated by the piston 16.

[0053] The primary chamber 31 is the region in which the valve portion 17B is disposed, and is the region from the primary port 2 of the body 11, which introduces hydrogen gas from the outside into the primary chamber 31, to the valve seat 14. The secondary chamber 32 is the region from the valve seat 14 to the secondary port 3 of the body 11. The secondary port 3 is the part of the body 11 that sends the hydrogen gas in the secondary chamber 32 to the outside. The atmospheric chamber 33 is the region in which the biasing member 18 is disposed, and is open to the atmosphere. The shaft portion 17A slidably penetrates the partition wall 21 in the axial direction and is connected to the valve portion 17B.

[0054] According to this configuration, it is not necessary to pass the shaft member connecting the piston 16 and the valve body 17 through the valve hole 14A, so that the cross-sectional area S １ The cross-sectional area S of the valve hole 14A can be reduced. １ The primary pressure P of the valve body 17 decreases by the amount Ｈ Since the pressure receiving area of ​​the piston 16 is narrowed, the cross-sectional area S ３ It is also possible to reduce the cross-sectional area S ３is the cross-sectional area of ​​the pressure-receiving portion 16A of the piston 16. Therefore, it is possible to reduce the size of the pressure reducing valve 1, particularly the size in the radial direction. This makes it possible to meet the demand for a more compact pressure reducing valve 1.

[0055] (1-2) The secondary chamber 32 has a first internal space 32A, a second internal space 32B, and a third internal space 32C. The first internal space 32A is disposed on the opposite side of the valve seat 14 from the valve body 17. The second internal space 32B is disposed on the opposite side of the piston 16 from the valve body 17. The third internal space 32C communicates with the first internal space 32A and the second internal space 32B. With this configuration, unlike when the piston 16 is disposed in the first internal space 32A, it is not necessary to pass a shaft member connecting the piston 16 and the valve body 17 through the valve hole 14A. Therefore, the cross-sectional area S of the valve hole 14A is １ can be made smaller.

[0056] (1-3) The third internal space 32C is provided in the peripheral wall of the body 11. According to this configuration, the peripheral wall of the body 11 can be used to connect the first internal space 32A and the second internal space 32B.

[0057] (1-4) Cross-sectional area S of the valve hole 14A １ and the cross-sectional area S of the shaft portion 17A ２ The primary pressure P Ｈ Changes in secondary pressure P Ｌ The primary pressure P may be set so that the fluctuation of the primary pressure P falls within an allowable range. Ｈ Changes in secondary pressure P Ｌ The degree of variation of the cross-sectional area S of the valve hole 14A is １ and the cross-sectional area S of the shaft portion 17A ２ Therefore, the cross-sectional area S of the valve hole 14A is １ and the cross-sectional area S of the shaft portion 17A ２ Through the setting of the primary pressure P Ｈ Changes in secondary pressure P Ｌ fluctuations can be kept within an acceptable range.

[0058] (1-5) Cross-sectional area S of the valve hole 14A １ is the cross-sectional area S of the shaft portion 17A ２ As described above, ideally, the cross-sectional area S of the shaft portion 17A２ According to this configuration, the primary pressure P Ｈ Therefore, the valve element 17 is prevented from being pushed in the valve opening direction, and the responsiveness of the pressure reducing valve 1 when it is closed can be ensured.

[0059] (1-6) Cross-sectional area S of the valve hole 14A １ and the cross-sectional area S of the shaft portion 17A of the valve body 17 ２ and are about the same (S １ ≒S ２ ), the cross-sectional area S of the piston 16 ３ Without increasing the primary pressure P Ｈ Changes in secondary pressure P Ｌ fluctuations can be suppressed.

[0060] (1-7) Cross-sectional area S of the valve hole 14A １ and the cross-sectional area S of the shaft portion 17A of the valve body 17 ２ and are about the same (S １ ≒S ２ ) In the case of the primary pressure P of the valve body 17 Ｈ Pressure load F ＰＨ１ is an approximate value of "0". Ｈ Even if the pressure rises, the load on the valve seat 14 does not increase, and the life of the valve seat 14 can be secured.

[0061] (1-8) For example, unlike when the piston 16 is disposed in the first internal space 32A, there is no need to pass the shaft member connecting the piston 16 and the valve body 17 through the valve hole 14A. This makes it easier to ensure the flow path cross-sectional area of ​​the valve hole 14A. This makes it possible to accommodate a large flow rate.

[0062] Second Embodiment Next, a pressure reducing valve 1 according to a second embodiment will be described. This embodiment has a configuration basically similar to that of the first embodiment shown in Fig. 1, but differs from the first embodiment in the arrangement of the communication holes 24. Therefore, the same members and configurations as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0063] 3, the communication passage 24 may be provided so as to axially penetrate the piston 16 and the valve body 17. That is, the third internal space 32C penetrates the valve body 17 and the piston 16 in the axial direction.

[0064] <Advantages of the Second Embodiment> The second embodiment has the following advantages. (2-1) The first internal space 32A and the second internal space 32B can be communicated with each other by utilizing the valve body 17 and the piston 16. Therefore, the same advantages as those of the first embodiment can be obtained. Furthermore, compared to when the communication passage 24 is provided in the peripheral wall of the body 11, the body 11 can be made smaller in the radial direction.

[0065] <Third embodiment> Next, a pressure reducing valve 1 according to a third embodiment will be described. This embodiment has a configuration basically similar to that of the first embodiment shown in Fig. 1, but differs from the first embodiment in the connection structure between the piston 16 and the valve body 17. Therefore, the same members and configurations as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0066] If the piston 16 and the valve element 17 are fixed, the valve element 17 will also tilt when the piston 16 tilts. If the valve element 17 tilts, there is a risk that the sealing performance between the valve portion 17B and the valve seat 14 will be reduced. Therefore, in this embodiment, the pressure reducing valve 1 has the following configuration.

[0067] As shown in FIG. 4 , the piston 16 and the valve element 17 are separable from each other. That is, the piston 16 and the valve element 17 are not fixed to each other. The piston 16 is a cylindrical body with a circular cross-sectional shape. The piston 16 has a stopper 16E. The stopper 16E is, for example, a columnar body with a circular or rectangular cross-sectional shape, and is provided at the center of the surface of the piston 16 opposite the valve element 17. Movement of the piston 16 in the valve opening direction is restricted by the stopper 16E abutting against the coupling member 12. For example, the stopper 16E may abut against the coupling member 12 when the valve element 71 moves from the valve closing position to the valve opening position.

[0068] The shaft portion 17A has a support portion 17E. The support portion 17E is, for example, an annular body provided on the outer peripheral surface of the shaft portion 17A. The support portion 17E extends radially outward from the outer peripheral surface of the shaft portion 17A. The support portion 17E is provided, for example, so that no gap is formed between the support portion 17E and the valve portion 17B in the axial direction. However, depending on the product specifications, the support portion 17E may be provided so that a gap is formed between the support portion 17E and the valve portion 17B in the axial direction. Alternatively, the support portion 17E may be provided on the outer peripheral surface of the valve portion 17B.

[0069] A second biasing member 19 is interposed between the support portion 17E and the valve seat 14. The biasing member 18 is the first biasing member. The second biasing member 19 may be, for example, a compression coil spring. The second biasing member 19 constantly biases the valve body 17 in the valve opening direction via the support portion 17E. The valve opening direction is the direction in which the valve portion 17B moves away from the valve seat 14. Biasing refers to the application of force in a specific direction. The support portion 17E may have an annular accommodating recess that opens toward the valve seat 14. The accommodating recess accommodates the end of the second biasing member 19 opposite the valve seat 14.

[0070] The first end of the shaft portion 17A is kept pressed against the piston 16 by the biasing force of the second biasing member 19. The first end is the end of the shaft portion 17A opposite the valve portion 17B. This allows the valve body 17 to move integrally with the piston 16.

[0071] The cross-sectional area S of the valve hole 14A in the direction perpendicular to the axial direction is １ is the cross-sectional area S in the direction perpendicular to the axial direction of the shaft portion 17A. ２ In this case, the cross-sectional area S １ and the cross-sectional area S of the shaft portion 17A ２ Depending on the difference between the pressures, gas pressure acts on the valve body 17 in a direction that presses the first end of the shaft portion 17A against the piston 16. That is, the first end of the shaft portion 17A is pressed against the piston 16 not only by the biasing force of the second biasing member 19 but also by the gas pressure. The gas pressure is a function of the primary pressure P Ｈ is.

[0072] Advantages of the Third Embodiment The third embodiment provides the following advantages. (3-1) The piston 16 and the valve element 17 are provided separately. The valve element 17 is connected to the piston 16 so as to be movable integrally therewith by maintaining a state in which a portion of the shaft portion 17A abuts against the piston 16 in the axial direction. The portion of the shaft portion 17A is a first end portion of the shaft portion 17A. The first end portion is an end portion of the shaft portion 17A opposite the valve portion 17B. Because the piston 16 and the valve element 17 are not fixedly connected, the tilting force of the piston 16 is not easily transmitted to the valve element 17. In other words, the valve element 17 is less likely to tilt in response to the tilting of the piston 16, making it easier to ensure sealing between the valve portion 17B and the valve seat 14.

[0073] (3-2) The second biasing member 19 constantly biases the shaft portion 17A in the axial direction so that a portion of the shaft portion 17A is pressed against the piston 16. The portion of the shaft portion 17A is a first end portion of the shaft portion 17A. Therefore, the first end portion of the shaft portion 17A is maintained in a state in which it is pressed against the piston 16 in the axial direction by the biasing force of the second biasing member 19. Therefore, when the pressure reducing valve 1 is activated, separation between the piston 16 and the valve body 17 can be suppressed.

[0074] (3-3) The shaft portion 17A has a support portion 17E. The support portion 17E includes a portion extending radially outward from the outer circumferential surface of the shaft portion 17A. The second biasing member 19 biases the shaft portion 17A in the valve-opening direction via the support portion 19E. The valve-opening direction is the direction in which the first end of the shaft portion 17A is pressed against the piston 16. With this configuration, the shaft portion 17A can be appropriately biased in the direction in which the first end of the shaft portion 17A is pressed against the piston 16.

[0075] (3-4) Cross-sectional area S of the valve hole 14A in a direction perpendicular to the axial direction １ is the cross-sectional area S in the direction perpendicular to the axial direction of the shaft portion 17A. ２ If the gap is narrower than 1 / 2 mm, when the pressure reducing valve 1 is activated, the first end of the shaft portion 17A is pressed against the piston 16 not only by the biasing force of the second biasing member 19 but also by the gas pressure. Therefore, when the pressure reducing valve 1 is activated, separation between the valve body 17 and the piston 16 can be suitably suppressed.

[0076] The cross-sectional area S of the valve hole 14A in the direction perpendicular to the axial direction is １ is the cross-sectional area S in the direction perpendicular to the axial direction of the shaft portion 17A. ２ If the gap is narrower than this, the second biasing member 19 can be omitted from the pressure reducing valve 1, and the support portion 17E can be omitted from the valve body 17. When this configuration is adopted, the first end of the shaft portion 17A is pressed against the piston 16 only by the gas pressure. Since there is no need to provide a configuration for biasing the shaft portion 17A in a direction that presses it against the piston 16, the configuration of the pressure reducing valve 1 can be simplified.

[0077] <Fourth embodiment> Next, a pressure reducing valve 1 according to a fourth embodiment will be described. This embodiment has a configuration basically similar to that of the third embodiment shown in Fig. 4, but differs from the third embodiment in the arrangement of the second biasing member 19. Therefore, the same members and configurations as those in the third embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0078] As shown in FIG. 5 , two grooves having a rectangular cross section are provided on the inner peripheral surface of the valve disc support hole 21A. Each of the two grooves extends around the entire inner periphery of the valve disc support hole 21A. The two grooves are spaced apart in the axial direction. A third seal member 21B and a fourth seal member 21C are attached to the two grooves, respectively. The fourth seal member 21C is closer to the atmospheric chamber 33 in the axial direction than the third seal member 21B. The groove in which the fourth seal member 21C is attached is open to the atmospheric chamber 33.

[0079] The third seal member 21B and the fourth seal member 21C may be, for example, an annular rubber packing having a Y-shaped cross section. However, in Fig. 5, for convenience of illustration, the cross sections of the third seal member 21B and the fourth seal member 21C are shown as circular. The third seal member 21B and the fourth seal member 21C ensure airtightness between the outer peripheral surface of the portion of the shaft portion 17A corresponding to the valve element support hole 21A and the inner peripheral surface of the valve element support hole 21A.

[0080] The body 11 has a relief passage 26. The relief passage 26, for example, connects the valve element support hole 21A and the communication passage 24. A first end of the relief passage 26 opens to a portion of the valve element support hole 21A between the third seal member 21B and the fourth seal member 21C. A second end of the relief passage 26 opens to an arbitrary position in the communication passage 24. The relief passage 26 is, for example, a linear passage extending radially of the body 11.

[0081] A plug 21D is fitted into the valve disc support hole 21A. The plug 21D is a cylindrical body with a circular cross section and includes an insertion portion and a flange portion. The insertion portion is the portion of the plug 21D that is inserted from the atmospheric chamber 33 side into the groove in which the fourth seal member 21C is fitted. The flange portion is the portion of the plug 21D that is provided at the end of the insertion portion that is closer to the atmospheric chamber 33. The flange portion is an annular body that is provided around the entire outer periphery of the insertion portion and extends radially outward from the outer periphery of the insertion portion. The outer diameter of the flange portion is larger than the inner diameter of the valve disc support hole 21A. The flange portion is in contact with the peripheral portion of the valve disc support hole 21A of the partition wall 21 that faces the atmospheric chamber 33. The plug 21D prevents the fourth seal member 21C from falling out of the groove.

[0082] The insertion portion may be attached by being screwed into the groove in which the fourth seal member 21C is mounted. For example, a male thread portion may be provided on the outer peripheral surface of the insertion portion, and a female thread portion may be provided on the inner peripheral surface of the groove in which the fourth seal member 21C is mounted.

[0083] The shaft portion 17A has a shaft portion main body 17F1 and a support portion 17F2. The shaft portion main body 17F1 is a columnar body with a circular cross-sectional shape. The support portion 17F2 is a cylindrical body with a circular cross-sectional shape. The support portion 17F2 has a support hole 17G. The support hole 17G is a blind hole extending in the axial direction of the valve body 17. The support hole 17G opens on the side opposite the piston 16. A first end of the shaft portion main body 17F1 is fitted into the support hole 17G. The first end is the end of the shaft portion main body 17F1 opposite the valve portion 17B. The shaft portion main body 17F1 moves integrally with the support portion 17F2. The shaft portion main body 17F1 may be fixed to the support portion 17F2 by, for example, a bolt. The support portion 17F2 is a part of the shaft portion 17A.

[0084] A second biasing member 19 is interposed between the flange of the plug 21D and the support portion 17F2. That is, the second biasing member 19 is disposed in the atmospheric chamber 33. The second biasing member 19 may be, for example, a compression coil spring. The second biasing member 19 constantly biases the valve element 17 in the valve opening direction via the support portion 17F2. The valve opening direction is the direction in which the valve portion 17B moves away from the valve seat 14.

[0085] The surface of the support portion 17F2 opposite to the support hole 17G is kept pressed against the piston 16 by the biasing force of the second biasing member 19. This allows the valve body 17 to move integrally with the piston 16.

[0086] The cross-sectional area S of the valve hole 14A in the direction perpendicular to the axial direction is １ is the cross-sectional area S in the direction perpendicular to the axial direction of the shaft portion 17A. ２ In this case, the cross-sectional area S １ and the cross-sectional area S of the shaft portion 17A ２ In accordance with the difference between the pressures P and P, gas pressure acts on the valve body 17 in a direction that presses the support portion 17F2 against the piston 16. That is, the surface of the support portion 17F2 opposite to the support hole 17G is pressed against the piston 16 not only by the biasing force of the second biasing member 19 but also by the gas pressure. Ｈ is.

[0087] <Effects of the Fourth Embodiment> The fourth embodiment provides the following effects. (4-1) When the second biasing member 19 is disposed in the primary chamber 31 as in the third embodiment, the following concerns arise. For example, if the second biasing member 19 is a compression coil spring, depending on the value of the spring constant, the second biasing member 19 may enter the valve hole 14A due to the flow of high-pressure gas when the pressure reducing valve 1 is activated. The smaller the value of the spring constant, the softer the second biasing member 19 becomes. According to this embodiment, the second biasing member 19 is disposed in the atmospheric chamber 33. Therefore, the second biasing member 19 is less susceptible to the flow of high-pressure gas. Therefore, the second biasing member 19 is maintained in an appropriately attached state.

[0088] (4-2) For example, there is a concern that the airtightness between the outer circumferential surface of the shaft portion 17A and the inner circumferential surface of the valve element support hole 21A may decrease due to aging of the third seal member 21B and the fourth seal member 21C. In this case, high-pressure gas supplied from the primary port 2 may flow into the atmosphere chamber 33 through the gap between the outer circumferential surface of the shaft portion 17A and the inner circumferential surface of the valve element support hole 21A and then be released into the atmosphere from the atmosphere chamber 33 through the atmosphere communication hole 25. According to the present embodiment, the body 11 has a relief passage 26. Therefore, gas flowing from the primary chamber 31 toward the atmosphere chamber 33 through the gap between the outer circumferential surface of the shaft portion 17A and the inner circumferential surface of the valve element support hole 21A flows through the relief passage 26 into the communication passage 24 and ultimately into the secondary chamber 32. This prevents gas from being released into the atmosphere.

[0089] (4-3) The piston 16 and the valve element 17 are provided separately. The valve element 17 is connected to the piston 16 so as to be movable integrally with the piston 16 by maintaining a state in which a portion of the shaft portion 17A abuts against the piston 16 in the axial direction. The support portion 17F2 is a portion of the shaft portion 17A. Because the piston 16 and the valve element 17 are not fixedly connected, the tilting force of the piston 16 is not easily transmitted to the valve element 17. In other words, because the valve element 17 is less likely to tilt in response to the tilt of the piston 16, it is easier to ensure sealing between the valve portion 17B and the valve seat 14.

[0090] (4-4) The second biasing member 19 constantly biases the shaft portion 17A in the axial direction so that a portion of the shaft portion 17A is pressed against the piston 16. The support portion 17F2 is a portion of the shaft portion 17A. Therefore, the support portion 17F2 is maintained in a state in which it is pressed against the piston 16 in the axial direction by the biasing force of the second biasing member 19. Therefore, when the pressure reducing valve 1 is activated, separation between the piston 16 and the valve body 17 can be suppressed.

[0091] (4-5) The shaft portion 17A has a shaft portion main body 17F1 and a support portion 17F2. The valve element 17B is provided at the end of the shaft portion main body 17F1. The support portion 17F2 is provided at the end of the shaft portion main body 17F2 opposite the valve portion 17B. The support portion 17F2 includes a portion extending radially outward from the outer circumferential surface of the shaft portion main body 17F1. The support portion 17F2 is a part of the shaft portion 17A. The second biasing member 19 biases the shaft portion 17A in the valve-opening direction via the support portion 17F2. The valve-opening direction is the direction in which the support portion 17F2 is pressed against the piston 16. This configuration allows the shaft portion 17A to be appropriately biased in the direction in which the support portion 17F2 is pressed against the piston 16.

[0092] (4-6) Cross-sectional area S of the valve hole 14A １ is the cross-sectional area S of the shaft portion 17A ２ If the gap is narrower than 17F2, when the pressure reducing valve 1 is activated, the support portion 17F2 is pressed against the piston 16 not only by the biasing force of the second biasing member 19 but also by the gas pressure. Therefore, when the pressure reducing valve 1 is activated, separation between the valve body 17 and the piston 16 can be suitably suppressed.

[0093] The cross-sectional area S of the valve hole 14A １ is the cross-sectional area S of the shaft portion 17A ２ If the gap is narrower than this, the second biasing member 19 can be omitted from the pressure reducing valve 1. When this configuration is adopted, the support portion 17F2 is pressed against the piston 16 only by the gas pressure. Since there is no need to provide a configuration for biasing the shaft portion 17A in a direction that presses it against the piston 16, the configuration of the pressure reducing valve 1 can be simplified.

[0094] Fifth Embodiment Next, a pressure reducing valve 1 according to a fifth embodiment will be described. This embodiment has a structure basically similar to that of the fourth embodiment shown in Fig. 5, but differs from the fourth embodiment in the arrangement of the second biasing member 19. Therefore, the same members and configurations as those in the forty-first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0095] 6 , the secondary port 3 is provided in the peripheral wall of the body 11. The secondary port 3 radially penetrates the peripheral wall of the body 11. The secondary port 3 connects the communication passage 24 with the outside of the body 11.

[0096] The piston 16 has a support hole 16F and a through hole 16G. The support hole 16F is a blind hole that opens to the secondary chamber 32 and has, for example, a circular cross-sectional shape. The through hole 16G axially penetrates a portion of the piston 16 that corresponds to the support hole 16F. The inner diameter of the through hole 16G is smaller than the inner diameter of the support hole 16F. The through hole 16G connects the support hole 16F to the atmospheric chamber 33. A groove is formed around the entire inner periphery of the inner surface of the through hole 16G. A fifth seal member 16H is attached to the groove. The fifth seal member 16H may be, for example, a rubber annular body and a packing having a Y-shaped cross-sectional shape. However, in FIG. 6, for convenience of illustration, the cross-sectional shape of the fifth seal member 16H is shown as a circle. The fifth seal member 16H ensures airtightness between the outer peripheral surface of the portion of the shaft portion 17A that corresponds to the through hole 16G and the inner peripheral surface of the through hole 16G.

[0097] The shaft portion 17A has a shaft portion main body 17H1 and a support portion 17H2. The shaft portion main body 17H1 is a columnar body having a circular cross-sectional shape. The support portion 17H2 is a two-stage cylindrical body having a circular cross-sectional shape. The support portion 17H2 includes an abutment portion 17I and a support shaft 17J. The abutment portion 17I is a cylindrical body having a circular cross-sectional shape. The abutment portion 17I has a support hole 17K. The support hole 17K is a blind hole extending in the axial direction of the valve body 17 and opens on the surface of the abutment portion 17I opposite the secondary chamber 32. The support shaft 17J is a columnar body having a circular cross-sectional shape and is provided on the surface of the abutment portion 17I opposite the support hole 17K. The outer diameter of the support shaft 17J is smaller than the outer diameter of the abutment portion 17I. The end of the support shaft 17J opposite to the contact portion 17I is located inside the secondary chamber 32.

[0098] A first end of the shaft body 17H1 is fitted into the support hole 17K via the through-hole 15G. The first end is the end of the shaft body 17H1 opposite the valve portion 17B. The shaft body 17H1 moves integrally with the support portion 17H2. The shaft body 17H1 may be fixed to the support portion 17H2 by, for example, a bolt. The support portion 17H2 is a part of the shaft 17A.

[0099] A second biasing member 19 is interposed between the contact portion 17I and the coupling member 12. The second biasing member 19 may be, for example, a compression coil spring. The second biasing member 19 constantly biases the valve element 17 in the valve closing direction via the contact portion 17I. The valve closing direction is the direction in which the valve portion 17B contacts the valve seat 14.

[0100] The surface of the abutment portion 17I opposite to the support shaft 17J is kept pressed in the axial direction against the inner end surface of the support hole 16F of the piston 16 by the biasing force of the second biasing member 19. This allows the valve body 17 to move integrally with the piston 16.

[0101] Alternatively, the coupling part 12 may be attached by screwing it into the first end of the body 11. For example, the outer peripheral surface of the coupling part 12 may be provided with a male thread, and the inner peripheral surface of the first end of the body 11 may be provided with a female thread. The coupling part 12 advances when the male thread is tightened against the female thread. The advancement of the coupling part 12 refers to the movement of the coupling part 12 toward the piston 16. The retreat of the coupling part 12 refers to the movement of the coupling part 12 away from the piston 16.

[0102] Furthermore, the pressure reducing valve 1 may be configured without the support hole 16. In this case, the axial distance between the piston 16 and the coupling member 12 is set to be longer than the axial length of the support portion 17H2. The biasing force of the second biasing member 19 keeps the abutment portion 17I pressed against the surface of the piston 16 facing the secondary chamber 32.

[0103] In addition, the cross-sectional area S of the valve hole 14A １ and the cross-sectional area S of the shaft portion 17A ２ may be set to the same size as in the first embodiment. <Advantages of the Fifth Embodiment> According to the fifth embodiment, the following advantages are achieved.

[0104] (5-1) The piston 16 and the valve element 17 are provided separately. The valve element 17 is connected to the piston 16 so as to be movable integrally with the piston 16 by abutting a portion of the shaft portion 17A against the piston 16 in the axial direction. The support portion 17H2 is a portion of the shaft portion 17A. Because the piston 16 and the valve element 17 are not fixedly connected, the tilting force of the piston 16 is not easily transmitted to the valve element 17. In other words, because the valve element 17 is less likely to tilt in response to the tilt of the piston 16, it is easier to ensure sealing between the valve portion 17B and the valve seat 14.

[0105] (5-2) The second biasing member 19 constantly biases the shaft portion 17A in the axial direction so that a portion of the shaft portion 17A is pressed against the piston 16. The support portion 17H2 is a portion of the shaft portion 17A. Therefore, the support portion 17H2 is maintained in a state in which it is pressed against the piston 16 in the axial direction by the biasing force of the second biasing member 19. Therefore, when the pressure reducing valve 1 is activated, separation between the piston 16 and the valve body 17 can be suppressed.

[0106] (5-3) The shaft portion 17A penetrates the piston 16 in the axial direction. The support portion 17H2 is a part of the shaft portion 17A. The support portion 17H2 includes a portion extending radially outward from the outer circumferential surface of the shaft portion 17A. The support portion 17H2 is disposed on the opposite side of the piston 16 from the valve portion 17B. The second biasing member 19 biases the valve body 17 in a valve closing direction via the support portion 17H2. The valve closing direction is the direction opposite to the valve opening direction, and is the direction in which the support portion 17H2 is pressed against the piston 16. With this configuration, the shaft portion 17A can be appropriately biased in the direction in which the support portion 17H2 is pressed against the piston 16.

[0107] Furthermore, even if the secondary pressure becomes excessively large, the force urging the valve element 17 in the valve closing direction is only the urging force of the second urging member 19. Because no force that moves the valve element 17 in the valve closing direction is applied to the valve element 17 from the piston 16, it is possible to prevent the valve element 17 from being pressed by the piston 16 and crushing the valve seat 14. Therefore, the valve seat 14 can be protected.

[0108] (5-4) When the second biasing member 19 is, for example, a compression coil spring, the spring load of the compression coil spring can be adjusted by tightening or loosening the male thread portion of the coupling member 12 relative to the female thread portion at the first end of the body 11. In other words, by tightening or loosening the male thread portion of the coupling member 12 relative to the female thread portion at the first end of the body 11, the pressure at which the valve element 17 closes can be adjusted.

[0109] <Sixth embodiment> Next, a pressure reducing valve 1 according to a sixth embodiment will be described. This embodiment has a structure basically similar to that of the fifth embodiment shown in Fig. 6, but differs from the fifth embodiment in the structure of the piston 16. This embodiment is made from the viewpoint of integrating the plug 21D and the piston 16. Therefore, the same members and structures as those in the fifth embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0110] As shown in FIG. 7 , the piston 16 has a large diameter portion 16I and a small diameter portion 16J. The large diameter portion 16I has a configuration similar to that of the piston 16 of the fifth embodiment shown in FIG. 6 . The small diameter portion 16J is a cylindrical body with a circular cross section and is located at the center of the surface of the large diameter portion 16I facing the atmospheric chamber 33. The outer diameter of the small diameter portion 16J is smaller than that of the large diameter portion 16I. The inner diameter of the small diameter portion 16J is approximately the same as or slightly larger than the outer diameter of the shaft portion 17A. The shaft portion 17A penetrates the piston 16 in the axial direction. The outer peripheral surface of the shaft portion 17A is axially slidable relative to the inner peripheral surface of the small diameter portion 16J.

[0111] The tip of the small diameter portion 16J passes through the atmospheric chamber 33 and is axially fitted into a groove provided on the inner circumferential surface of the valve element support hole 21A of the partition wall 21. The tip is the end of the small diameter portion 16J opposite the large diameter portion 16I. This groove is the same groove where the fourth seal member 21C was attached in the fifth embodiment shown in FIG. 6 and is open to the atmospheric chamber 33. The outer circumferential surface of the small diameter portion 16J is axially slidable relative to the inner circumferential surface of the groove. A groove having a rectangular cross section is provided on the inner circumferential surface near the tip of the small diameter portion 16J. The groove extends around the entire inner periphery of the small diameter portion 16J. A fourth seal member 21C is attached to the groove. The fourth seal member 21C ensures airtightness between the inner circumferential surface of the small diameter portion 16J and the outer circumferential surface of the shaft portion 17A.

[0112] The cross-sectional area S of the valve hole 14A １ and the cross-sectional area S of the shaft portion 17A ２ may be set to the same size as in the first embodiment. <Effects of the Sixth Embodiment> According to the sixth embodiment, in addition to the effects described in (5-1) to (5-4) above, the following effects are achieved.

[0113] (6-1) The large diameter portion 16I and the small diameter portion 16J of the piston 16 are integrally formed. The tip of the small diameter portion 16J passes through the atmosphere chamber 33 and is axially fitted into the inner circumferential surface of the valve element support hole 21A of the partition wall 21. Therefore, if the airtightness between the outer circumferential surface of the shaft portion 17A and the inner circumferential surface of the valve element support hole 21A decreases, for example, high-pressure gas supplied from the primary port 2 passes through the gap between the outer circumferential surface of the shaft portion 17A and the inner circumferential surface of the valve element support hole 21A and flows into the support hole 16F and ultimately into the secondary chamber 32. In other words, it is possible to prevent the gas supplied from the primary port 2 from being released into the atmosphere. This allows the body 11 to omit the relief passage 26 of the fifth embodiment shown in FIG. 6 . By omitting the relief passage 26, the axial length of the body 11 can be shortened.

[0114] (6-2) Because the large diameter portion 16I and the small diameter portion 16J are integrally formed, the plug 21D of the fifth embodiment shown in Fig. 6 can be omitted. This reduces the number of parts of the pressure reducing valve 1. The configuration of the pressure reducing valve 1 can also be simplified.

[0115] Other Embodiments Each embodiment may be modified as follows: The biasing member 18 may be, for example, a disc spring instead of a compression coil spring. The biasing member 18 may be any elastic member that constantly biases the piston 16 in the valve-opening direction.

[0116] The biasing member 18 is the first biasing member. The second biasing member 19 may be, for example, a disc spring instead of a compression coil spring. The second biasing member 19 may be any elastic member that constantly biases the piston 16 in the valve-opening direction or the valve-closing direction.

[0117] The pressure reducing valve 1 may be used to reduce the pressure of high-pressure gases other than hydrogen.

Claims

1. A gas flow path comprising: a body having a gas flow path; a valve seat provided midway through the gas flow path, the valve seat having a valve hole penetrating the valve seat in the axial direction of the body; a valve disc configured to open and close the valve seat; a piston connected to the valve disc; and a biasing member configured to constantly bias the piston in a valve opening direction, wherein the valve disc has a shaft connected to the piston and a valve section provided at an end of the shaft and configured to open and close the valve seat, the gas flow path comprising a primary chamber, a secondary chamber, and an atmospheric chamber, the primary chamber and the secondary chamber being separated by the valve seat, and the primary chamber and the atmospheric chamber being separated by a partition wall extending in a direction perpendicular to the axial direction of the body, and the secondary chamber and the atmospheric chamber being separated by the piston, the body having a primary port configured to introduce gas from the outside into the primary chamber and a secondary port configured to send gas in the secondary chamber to the outside, the primary chamber being an area in which the valve section is located, the area being from the primary port to the valve seat, a pressure reducing valve in which the secondary chamber is a region from the valve seat to the secondary port, the atmospheric chamber is a region in which the biasing member is disposed and is open to the atmosphere, and the shaft portion slidably penetrates the partition wall in the axial direction and is connected to the valve portion.

2. A pressure reducing valve as claimed in claim 1, wherein the secondary chamber has a first internal space, a second internal space and a third internal space, the first internal space being located on the opposite side of the valve seat from the valve body, the second internal space being located on the opposite side of the piston from the valve body, and the third internal space communicating with the first internal space and the second internal space.

3. A pressure reducing valve as set forth in claim 2, wherein the third internal space is provided in the peripheral wall of the body.

4. A pressure reducing valve as set forth in claim 2, wherein the third internal space passes through the valve body and the piston in the axial direction.

5. A pressure reducing valve as claimed in any one of claims 1 to 4, wherein the cross-sectional area of ​​the valve hole and the cross-sectional area of ​​the stem are set so that fluctuations in secondary pressure in response to changes in primary pressure fall within an allowable range.

6. A pressure reducing valve as set forth in claim 5, wherein the cross-sectional area of ​​the valve hole is equal to or greater than the cross-sectional area of ​​the stem portion.

7. A pressure reducing valve as claimed in claim 1, wherein the valve element and the piston are separable from each other, and the valve element is connected to the piston so as to be movable integrally with it by maintaining a state in which a portion of the shaft portion is in axial contact with the piston.

8. The pressure reducing valve according to claim 7, wherein the biasing member is a first biasing member, and further comprises a second biasing member configured to constantly bias the shaft portion in the axial direction so that a portion of the shaft portion is pressed against the piston.

9. A pressure reducing valve as described in claim 8, wherein the shaft portion slidably passes through the piston in the axial direction, a part of the shaft portion is a support portion including a portion extending radially outward from the outer peripheral surface of the shaft portion, the support portion is arranged on the opposite side of the piston from the valve portion, and the second biasing member is configured to bias the shaft portion via the support portion.

10. A pressure reducing valve as described in claim 8, wherein the shaft portion has a shaft portion main body having the valve body at its end, and a support portion provided at the end of the shaft portion main body opposite the valve portion and including a portion extending radially outward from the outer circumferential surface of the shaft portion main body, a part of the shaft portion being the support portion, and the second biasing member is configured to bias the shaft portion via the support portion.

11. A pressure reducing valve as described in claim 8, wherein a part of the shaft portion is an end of the shaft portion opposite the valve portion, the shaft portion has a support portion including a portion extending radially outward from the outer peripheral surface of the shaft portion, and the second biasing member is configured to bias the shaft portion via the support portion.

12. A pressure reducing valve as claimed in claim 10 or 11, wherein the cross-sectional area of ​​the valve hole is smaller than the cross-sectional area of ​​the stem portion.

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