JP2013161436A - Pressure reduction valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve miniaturization with simple configurations while having a relief function in a pressure reduction valve.SOLUTION: When the pressure of a pressure reduction chamber 15 exceeds a threshold, a piston 12 reaches a specific position by deforming a stopper member 21. When the piston 12 reaches the specific position, a seal member 16 reaches a leak mechanism 26. Then, the pressure reduction chamber 15 is not completely sealed by the seal member 16, and so-called seal leakage occurs. Therefore, any excessive pressure rise in the pressure reduction chamber 15 can be suppressed. Thus, a pressure reduction valve 30 can have a relief function for, when the pressure of the pressure reduction chamber 15 becomes the threshold or more, decreasing the pressure.

Description

  The present invention relates to a pressure reducing valve.

  In recent years, fuel cell vehicles that do not emit carbon dioxide have attracted attention because of environmental considerations. This fuel cell vehicle includes a fuel supply system that supplies hydrogen as a fuel. As shown in FIG. 5, this system includes a hydrogen tank 52 that stores hydrogen serving as a fuel, and a stack 51 that chemically reacts hydrogen and oxygen. Between the hydrogen tank 52 and the stack 51, an injector 53 for adjusting the supply of hydrogen to the stack 51 and a pressure reducing valve 10 for a high-pressure hydrogen tank for reducing a pressure difference between the hydrogen tank 52 and the stack 51 are provided. ing.

As shown in FIG. 6, the pressure reducing valve 10 includes a cylindrical cylinder 11 a formed on the upper portion of the body 11 and a columnar piston 12 that can move up and down in the cylinder 11 a.
The piston 12 has a spring accommodating hole 12a that opens upward while being accommodated in the cylinder 11a. The coil spring 13 biases the piston 12 downward by being positioned between the inner top surface of the cylinder 11a and the bottom surface of the spring housing hole 12a. A portion of the cylinder 11a that houses the piston 12 corresponds to a cylindrical portion.

  In the cylinder 11a, a partitioning portion 14 is formed at a position spaced downward from the piston 12. A decompression chamber 15 connected to the injector 53 is formed between the piston 12 and the partition portion 14. In order to seal between the decompression chamber 15 and the space above the piston 12 (low pressure side space), an annular rubber seal member 16 is fitted on the outer periphery of the piston 12. The seal member 16 keeps the above-described sealed state by sliding on the inner peripheral surface of the cylinder 11 a as the piston 12 moves.

  An annular wear ring 35 made of resin is fitted on the outer peripheral surface of the piston 12. In this example, two wear rings 35 are provided at positions where the seal member 16 is sandwiched along the axial direction of the piston 12. When the piston 12 moves up and down in the cylinder 11a, each wear ring 35 slides on the inner peripheral surface of the cylinder 11a. Thereby, the reciprocating movement of the piston 12 becomes smooth.

  Hydrogen gas from the hydrogen tank 52 flows into the space 17 below the partition 14. A through hole 14a is formed in the partition part 14, and a poppet 18 extending in the vertical direction is inserted through the through hole 14a. Specifically, the poppet 18 includes a cylindrical main body portion 18a, a columnar tip portion 18b having a diameter smaller than that of the main body portion 18a, and a tapered surface 18c that connects the main body portion 18a and the tip portion 18b.

  The through-hole 14a has a tapered surface 14b having the same circular diameter from the decompression chamber 15 side to the center thereof in the thickness direction of the partitioning portion 14, and the circular diameter gradually increasing from the center to the lower end surface. Is formed. The tapered surface 18c of the poppet 18 is formed so as to be in surface contact with the tapered surface 14b. In a state where the tapered surface 18 c is in surface contact with the tapered surface 14 b, the tip end portion 18 b of the poppet 18 projects toward the decompression chamber 15 through the through hole 14 a of the partition portion 14. Moreover, the pin 20 is provided in the front end surface of the front-end | tip part 18b. The upper surface of the pin 20 is in contact with the lower surface of the piston 12.

  In addition, a pin plug 19 that covers the outer periphery of the pin 20 is integrally formed in the partition portion 14. When the lower end surface of the piston 12 is in contact with the upper surface of the pin plug 19, the downward stroke of the piston 12 is limited.

In the above configuration, the pressure in the decompression chamber 15 is kept constant throughout the operations of the piston 12, the pin 20 and the poppet 18.
When the pressure in the decompression chamber 15 is lower than a certain value, the piston 12 moves downward according to the biasing force of the coil spring 13. As the piston 12 moves, the pin 20 and thus the poppet 18 move downward. Therefore, the tapered surface 18c of the poppet 18 is separated from the tapered surface 14b of the through hole 14a. As a result, hydrogen gas flows into the decompression chamber 15 from the gap between the poppet 18 and the partition portion 14, and the pressure in the decompression chamber 15 increases.

  For example, when the pressure in the decompression chamber 15 becomes a certain value or more, the piston 12 moves upward while resisting the urging force of the coil spring 13 due to the pressure. As the piston 12 moves, the poppet 18 and thus the pin 20 move upward. Therefore, the tapered surface 18c of the poppet 18 comes into surface contact with the tapered surface 14b of the through hole 14a. Thereby, the inflow of hydrogen gas into the decompression chamber 15 is suppressed, and the pressure increase in the decompression chamber 15 is suppressed (for example, refer to Patent Documents 1 and 2).

  In particular, since high-pressure hydrogen gas is handled in a fuel cell vehicle, the pressure in the decompression chamber 15 may increase excessively regardless of the pressure control described above. For this reason, the pressure reducing valve 10 is provided with a relief valve that releases the pressure to the outside when the pressure in the pressure reducing chamber 15 exceeds a threshold value (see, for example, Patent Document 3).

JP 2004-192462 A JP 2006-164210 A JP 2004-360491 A

  However, since the relief valve is built in the body 11 of the pressure reducing valve 30 in a manner communicating with the pressure reducing chamber 15, for example, the size of the pressure reducing valve 10 is increased. Further, it is necessary to form a hydrogen gas flow path that connects the decompression chamber 15 to the atmosphere in the body 11 with the installation of the relief valve. For this reason, the processing of the body 11 is also complicated.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a pressure reducing valve that has a relief function and is downsized with a simple configuration.

Hereinafter, means for achieving the above-described object and its operation and effects will be described.
The invention according to claim 1 divides the inside of the cylinder into a high-pressure side space and a low-pressure side space, and is biased through a coil spring from the low-pressure side space toward the high-pressure side space. In a state where the piston reciprocates in the axial direction according to the difference between the biasing force and the outer periphery of the piston, and slides on the inner peripheral surface of the cylinder as the piston reciprocates, A pressure-reducing valve that seals between the high-pressure side space and the low-pressure side space in the cylinder in a sealed state, and the one-way in the reciprocating movement of the piston accompanying a rise in pressure in the high-pressure side space A stopper member that is deformed by the pressing force of the piston when the pressure in the high-pressure side space exceeds a first predetermined value, and the piston is Upon reaching the first predetermined position by deforming the, a flow path forming means for forming a flow path for releasing the pressure from the high-pressure side space, further comprising a has as its gist.

  According to this configuration, when the pressure in the high-pressure side space exceeds the first predetermined value, the stopper member is deformed by the pressing force of the piston. Thereby, a flow path is formed between the seal member and the cylinder, and gas flows from the high pressure side space to the low pressure side space through the flow path. Therefore, the pressure reducing valve can be provided with a relief function that suppresses the pressure exceeding the first predetermined value. In this configuration, since the relief valve is not necessary for the pressure reducing valve, the pressure reducing valve can be downsized.

According to a second aspect of the present invention, in the pressure reducing valve according to the first aspect, the stopper member is accommodated in the low-pressure side space, and the pressure in the high-pressure side space is smaller than the first predetermined value. When it is less than a predetermined value of 2, it is in a state of being in contact with the piston in a mode of moving integrally with the piston or in a state of being in contact of the cylinder in a mode of relative movement with the piston
When the pressure in the high-pressure side space reaches the second predetermined value, the piston moves to the second predetermined position by the pressure, and comes into contact with the piston and the cylinder. Is the gist.

  According to this configuration, when the pressure in the high-pressure side space is less than the second predetermined value, the piston is separated from the stopper member or the cylinder, so that the biasing force of the coil spring and the pressure in the high-pressure side space are in accordance. The position can be balanced with the pressing force of the piston. In this way, the piston moves according to the pressure in the high-pressure side space, so that the high-pressure side space can be accurately decompressed.

  According to a third aspect of the present invention, in the pressure reducing valve according to the first or second aspect, the stopper member includes the piston and the cylinder when the pressure in the high-pressure side space reaches the second predetermined value. When the pressure in the reciprocating movement of the piston is restricted, the pressure in the high-pressure side space exceeds the first predetermined value. The gist is that it is deformed by the pressing force from the piston.

  According to this configuration, the stopper member functions as a stopper when the pressure in the high-pressure side space is in the normal range (second predetermined value or less). By exhibiting this function, it is possible to suppress the excessive movement of the piston (overstroke) due to a sudden pressure increase and excessive expansion and contraction of the coil spring, and hence the coil spring sag. In addition, when the pressure in the high-pressure side space greatly exceeds the normal range (when exceeding the first predetermined value), the relief function that suppresses the pressure in the high-pressure side space by deforming the stopper member is exhibited. Can do.

  According to a fourth aspect of the present invention, in the pressure reducing valve according to any one of the first to third aspects, the stopper member is formed of a brittle material, and the pressure in the high-pressure side space is the first pressure. The gist is to break by the pressing force when a predetermined value is exceeded.

  According to this configuration, when the pressure in the high-pressure side space exceeds the first predetermined value, the piston breaks the stopper member. For this reason, the piston instantaneously reaches the first predetermined position. Therefore, the pressure increase in the high-pressure side space is quickly suppressed.

  According to a fifth aspect of the present invention, in the pressure reducing valve according to any one of the first to third aspects, the stopper member is formed of an elastic material, and the pressure in the high pressure side space is the first pressure. The gist is that when a predetermined value is exceeded, elastic deformation is caused by the pressing force through the piston.

  According to this configuration, when the pressure in the high pressure side space exceeds the first predetermined value, the piston elastically deforms the stopper member. Then, after the piston reaches the first predetermined position and the pressure increase in the high-pressure side space is suppressed, the stopper member returns to the original state again. Therefore, the replacement frequency of the stopper member can be reduced.

  According to a sixth aspect of the present invention, in the pressure reducing valve according to any one of the first to third aspects, the flow path forming means is provided on an inner surface of a cylindrical portion that houses the piston as a part of the cylinder. A concave portion formed and expanded at least partially in the circumferential direction of the cylindrical portion, and when the piston reaches the first predetermined position, the concave shape is reached when the seal member reaches the concave portion. The gist is that a flow path from the high-pressure side space to the low-pressure side space is formed.

  According to this configuration, when the piston reaches the first predetermined position by deforming the stopper member, the seal member reaches the recess. As a result, the high-pressure side space cannot be completely sealed by the seal member, and so-called seal leakage occurs. Therefore, an excessive pressure increase in the high pressure side space is suppressed.

  According to a seventh aspect of the present invention, in the pressure reducing valve according to any one of the first to third aspects, the flow path forming means is provided on an inner surface of a cylindrical portion that houses the piston as a part of the cylinder. A projecting portion formed to reduce a diameter of at least a part of the cylindrical portion in the circumferential direction, wherein the seal member reaches the projecting portion when the piston reaches the first predetermined position. The gist is that a flow path from the high-pressure side space to the low-pressure side space is formed through the gap between the seal member and the cylinder.

  According to this configuration, when the piston reaches the first predetermined position by deforming the stopper member, the seal member reaches the protrusion. As a result, the high-pressure side space cannot be completely sealed by the seal member, and so-called seal leakage occurs. Therefore, an excessive pressure increase in the high pressure side space is suppressed.

  According to an eighth aspect of the present invention, in the pressure reducing valve according to any one of the first to third aspects, the flow path forming means is formed from the inside of a cylindrical portion that houses the piston as a part of the cylinder. A through-hole penetrating to the outside of the pressure-reducing valve, and when the piston reaches the first predetermined position, the pressure-reducing pressure is reduced from the high-pressure side space through the through-hole when the seal member reaches the through-hole. The gist is that a flow path to the outside of the valve is formed.

  According to this configuration, when the piston reaches the first predetermined position by deforming the stopper member, the seal member reaches the through hole. As a result, the high-pressure side space cannot be completely sealed by the seal member, and seal leakage occurs through the through hole. Therefore, an excessive pressure increase in the high pressure side space is suppressed.

  According to the present invention, it is possible to reduce the size with a simple configuration while having a relief function.

Sectional drawing of the pressure-reduction valve in one Embodiment of this invention. (A)-(c) in one Embodiment of this invention is sectional drawing of a pressure-reduction valve. (A) And (b) in other embodiments is a partial expanded sectional view of a pressure-reduction valve. The perspective view of the stopper member in other embodiments. The block diagram which showed the structure of the fuel supply system of the fuel cell vehicle in background art and one Embodiment of this invention. Sectional drawing of the pressure-reduction valve in background art.

A first embodiment in which a pressure reducing valve according to the present invention is embodied in a fuel supply system for a fuel cell vehicle will be described below with reference to FIGS. 1 and 2.
The fuel supply system of the present embodiment has the same configuration as that of FIG. Therefore, the description of the configuration of the fuel supply system here is omitted, and the pressure reducing valve 30 in the system will be described.

  As shown in FIG. 1, the pressure reducing valve 30 includes a cylinder 11a, a piston 12, a coil spring 13, a stopper member 21, a wear ring 35, a seal member 16, a partition portion 14, a pin plug 19, and a pin. 20 and a poppet 18. Since the piston 12, the coil spring 13, the partition 14, the pin plug 19, the pin 20, and the poppet 18 have the same configuration as the above-described background art, description thereof is omitted. The following description will focus on differences from the background art and points not described in the background art.

  An annular corresponding portion 22 is formed on the inner top surface of the cylinder 11a. The lower surface 22 a of the corresponding portion 22 faces the upper end surface 12 b of the piston 12 in the axial direction of the piston 12. A stopper member 21 is provided between the lower surface 22 a of the corresponding portion 22 and the upper end surface 12 b of the piston 12.

  The stopper member 21 is made of a brittle material such as ceramic or glass. The stopper member 21 has an annular shape and a substantially Z-shaped cross section. One end of the stopper member 21 is fixed to the lower surface 22a of the corresponding portion 22, and the other end is not fixed. As a result, the piston 12 contacts and separates from the upper end surface 12b of the piston 12. The stopper member 21 is designed to be broken by a pressing force through the piston 12 when the pressure in the decompression chamber 15 exceeds a threshold value (first predetermined value). This threshold value is set based on the pressure resistance range of the pressure reducing valve 30 and the injector 53. The decompression chamber 15 corresponds to the high-pressure side space, and the space above the piston 12 partitioned from the decompression chamber 15 through the seal member 16 corresponds to the low-pressure side space. The pressing force is a force that moves the piston 12 toward the low-pressure side space in accordance with the pressure in the high-pressure side space.

  As shown enlarged in the circle of FIG. 1, an annular leak groove 26 is formed on the inner peripheral surface of the cylinder 11 a corresponding to the outer peripheral surface of the piston 12. The leak groove 26 corresponds to a flow path forming means and a recess. In normal times when the stopper member 21 is not broken, the seal member 16 is positioned below the leak groove 26. In this state, the decompression chamber 15 is sealed by the seal member 16 contacting the inner peripheral surface of the cylinder 11 a and the outer peripheral surface of the piston 12.

Next, the operation of the pressure reducing valve 30 will be described.
When the pressure in the decompression chamber 15 becomes lower than a certain value (second predetermined value), the piston 12 moves downward according to the urging force of the coil spring 13. When the lower end surface of the piston 12 is in contact with the upper surface of the pin plug 19, the downward stroke of the piston 12 is limited. At this time, the upper end surface 12 b of the piston 12 is separated from the stopper member 21. As the piston 12 moves, the pin 20 and thus the poppet 18 move downward. Accordingly, the tapered surface 18 c of the poppet 18 is separated from the tapered surface 14 b of the through hole 14 a and hydrogen gas flows into the decompression chamber 15. Therefore, the pressure in the decompression chamber 15 increases.

  When the pressure in the decompression chamber 15 exceeds a certain value, the piston 12 moves upward against the urging force of the coil spring 13 due to the pressure. As the piston 12 moves, the pin 20 and thus the poppet 18 move upward. Then, when the upper end surface 12b of the piston 12 contacts the stopper member 21, the upward stroke of the piston 12 is limited. The piston 12 is in the second predetermined position when it comes into contact with the stopper member 21. At this time, although a pressing force is applied to the stopper member 21, it does not deform or break. In this state, the tapered surface 18c of the poppet 18 comes into contact with the tapered surface 14b of the through hole 14a, and the inflow of hydrogen gas into the decompression chamber 15 is suppressed. Therefore, the pressure rise in the decompression chamber 15 is suppressed.

  However, even when the pressure increase in the decompression chamber 15 is suppressed as described above, the pressure in the decompression chamber 15 may be larger than the predetermined value in a situation where it is exposed to an abnormally high temperature. . In this case, the stopper member 21 is broken by the pressing force of the piston 12 as shown in FIG. As a result, as shown in FIG. 2A, the piston 12 moves further upward from the overstroke, that is, the position shown in FIG. 1, and reaches a specific position (first predetermined position). When the piston 12 is in a specific position, the lower end surface of the piston 12 is separated from the upper surface of the pin 20. Further, as shown in FIG. 2C, when the piston 12 is in a specific position, the seal member 16 is in a position corresponding to the leak groove 26. In this state, a gap (that is, a leak groove 26) is generated between the seal member 16 and the cylinder 11a. Therefore, when the decompression chamber 15 cannot be completely sealed by the seal member 16, so-called seal leakage occurs. As shown by a one-dot chain line in FIG. Leaks into the space (low pressure side space). Therefore, an excessive pressure increase in the decompression chamber 15 is suppressed.

As described above, according to the embodiment described above, the following effects can be obtained.
(1) When the pressure in the decompression chamber 15 exceeds the threshold value, the piston 12 reaches a specific position by deforming the stopper member 21 (including the concept of fracture in this example). When the piston 12 reaches a specific position, the seal member 16 reaches the leak groove 26. As a result, the decompression chamber 15 cannot be completely sealed by the seal member 16, and so-called seal leakage occurs. Accordingly, an excessive pressure increase in the decompression chamber 15 is suppressed. Therefore, the pressure reducing valve 30 can be provided with a relief function for reducing the pressure when the pressure reducing chamber 15 has a pressure equal to or higher than the threshold value. In this configuration, since it is not necessary to provide the pressure reducing valve 30 with the relief valve described in the background art, the pressure reducing valve 30 can be downsized. Moreover, the processing of the body 11 is also unnecessary.

  (2) When the pressure in the decompression chamber 15 exceeds the threshold value, the piston 12 breaks the stopper member 21. For this reason, the piston 12 reaches a specific position instantly. Therefore, the pressure increase in the decompression chamber 15 is quickly suppressed.

  In particular, since the stopper member 21 is formed in a Z-shaped cross section, it can be easily broken by concentrating the stress on a part. Further, the amount of overstroke in the upward direction of the piston 12 after the stopper member 21 is broken can be increased.

  (3) When the piston 12 reaches a specific position, the seal member 16 reaches the leak groove 26, and the leak groove 26 becomes a hydrogen gas flow path. At this time, the seal member 16 is hardly damaged. Therefore, the seal member 16 can be reused by replacing the stopper member 21 with a new one.

In addition, the said embodiment can be implemented with the following forms which changed this suitably.
In the above embodiment, when the pressure in the decompression chamber 15 exceeds the threshold value, an excessive pressure increase in the decompression chamber 15 is suppressed due to seal leakage through the leak groove 26. However, if the seal leakage can be caused when the pressure in the decompression chamber 15 exceeds the threshold value, for example, instead of the leak groove 26, as shown in FIG. It may be provided. In this configuration, when the stopper member 21 is broken, the piston 12 moves upward, so that the seal member 16 slides on the leak protrusion 40 and reaches the position indicated by the two-dot chain line in FIG. . As a result, the leak protrusion 40 separates a part of the seal member 16 from the inner surface of the cylinder 11a, or damages a part of the seal member 16, thereby creating a gap between the seal member 16 and the cylinder 11a. Leakage can occur. In other words, the size, shape, and number of the leak protrusions 40 are set such that seal leakage to the extent that the excessive pressure rise can be suppressed by passing the seal member 16 thereon.

Further, if a gap is generated between the seal member 16 and the cylinder 11a through the leak protrusion 40, the seal member 16 may not be damaged.
Instead of the leak groove 26, the inner peripheral diameter of the upper part from the position corresponding to the leak groove 26 (the lower end) of the body 11 may be made larger than the inner peripheral diameter of the lower part from the position. Also in this configuration, the same effect as that of the above embodiment can be obtained.

  Further, as shown in FIG. 3B, a through hole 44 may be formed in the cylinder 11a as a flow path forming means. The through hole 44 extends in a direction orthogonal to the axial direction of the piston 12 (left and right direction in the figure) and communicates the inside and the outside of the cylinder 11a. According to this configuration, the seal member 16 reaches the through hole 44 when the piston 12 deforms the stopper member 21. Thereby, hydrogen gas in the decompression chamber 15 leaks to the outside through the through hole 44. Accordingly, an excessive pressure increase in the decompression chamber 15 is suppressed.

  In the above embodiment, the stopper member 21 is a brittle material that breaks with little elastic deformation even when the pressing force through the piston 12 increases, but breaks when the piston 12 reaches a specific position. Instead, it may be formed of an elastic material such as rubber that is elastically deformed, or a plastic material such as metal that is plastically deformed.

  For example, when the stopper member 21 is formed of a plastic material, when the pressure in the decompression chamber 15 exceeds a threshold value, the stopper member 21 is plastically deformed so that the seal member 16 has a position corresponding to the leak groove 26. Become. Therefore, as in the above embodiment, excessive pressure rise in the decompression chamber 15 is suppressed through seal leakage. When the stopper member 21 is formed of an elastic material, the seal member 16 is positioned corresponding to the leak groove 26 by elastically deforming the stopper member 21. In the case of an elastic material, the stopper member 21 returns to its original shape again when the pressing force is lost, so the replacement frequency of the stopper member 21 can be reduced.

  In the above embodiment, the stopper member 21 is formed in a substantially Z-shaped cross section, but the cross-sectional shape is not limited to this, for example, the stopper member is formed in an S shape, a polygonal cross section or a circular cross section. May be. Further, only the portion to be broken in the cross-sectional shape of the stopper member 21 may be formed thin, or a notch may be formed in the portion. Thereby, the stopper member 21 can be broken at a fixed position.

  Moreover, as shown in FIG. 4, the stopper member 45 may be formed in an annular shape, and a plurality of through holes 45a may be formed in the thickness direction. In this example, the through hole 45a is formed in a diamond shape. Thus, by forming the plurality of through holes 45a in the stopper member 45, when the stopper member 45 is an elastic material, the elastic deformation can be facilitated. When the stopper member 45 is made of a brittle material, the breaking strength of the stopper member 45 can be arbitrarily set through the number or size of the through holes 45a. The shape of the through hole 45a is not limited to a rhombus, but may be a polygonal shape or a circle. Moreover, you may form the through-hole 45a in the stopper member 21 in the said embodiment.

  In the above embodiment, the shape and size of the leak groove 26 can be changed as appropriate. For example, in the above embodiment, the leak groove 26 is formed over the entire inner circumference of the cylinder 11a, but may be formed only in a part thereof.

In the above embodiment, the pressure reducing valve 30 is applied to the fuel supply system of the fuel cell vehicle. However, the pressure reducing valve 30 may be applied to other configurations that require pressure reduction.
In the above embodiment, the stopper member 21 is broken by the pressing force by the piston 12, but may be broken by the tensile force (negative pressing force) by the piston 12. In this case, for example, a configuration in which the stopper member 21 and the corresponding portion 22 are provided on the lower surface side of the piston 12 and both ends of the stopper member 21 are fixed to the corresponding portion 22 and the lower surface of the piston 12 is conceivable.

  DESCRIPTION OF SYMBOLS 11 ... Body, 11a ... Cylinder, 12 ... Piston, 12a ... Spring accommodation hole, 12b ... Upper end surface, 13 ... Coil spring, 14 ... Partition part, 15 ... Decompression chamber, 16 ... Seal member, 18 ... Poppet, 20 ... Pin 21, 45... Stopper member, 26... Leak groove as a flow path forming means, 30... Pressure reducing valve, 35.

Claims (8)

The cylinder is partitioned into a high-pressure side space and a low-pressure side space, energized through a coil spring from the low-pressure side space to the high-pressure side space, and according to the difference between the pressure in the high-pressure side space and the energizing force A piston that reciprocates in the axial direction,
A state in which the space between the high-pressure side space and the low-pressure side space in the cylinder is sealed by sliding on the inner peripheral surface of the cylinder with the reciprocating movement of the piston while being fitted to the outer periphery of the piston. A pressure reducing valve provided with a sealing member separated by
The piston is restricted from moving in one direction in the reciprocating movement of the piston accompanying the pressure increase in the high-pressure side space, and is deformed by the pressing force of the piston when the pressure in the high-pressure side space exceeds a first predetermined value. A stopper member to be
A pressure reducing valve comprising: a flow path forming means for forming a flow path for releasing pressure from the high pressure side space when the piston deforms the stopper member and reaches a first predetermined position. . The pressure reducing valve according to claim 1,
The stopper member is accommodated in the low-pressure side space,
When the pressure in the high-pressure side space is less than a second predetermined value that is smaller than the first predetermined value, in a state of being in contact with the piston in a mode of moving integrally with the piston, or in a mode of moving relative to the piston. A state in contact with the cylinder,
When the pressure in the high-pressure side space reaches the second predetermined value, the piston moves to a second predetermined position by the pressure, and comes into contact with the piston and the cylinder. A pressure reducing valve characterized by that. The pressure reducing valve according to claim 1 or 2,
The stopper member is
When the pressure in the high-pressure side space reaches the second predetermined value, it resists the pressing force from the piston while being in contact with the piston and the cylinder. The movement of
A pressure reducing valve that is deformed by a pressing force from the piston when a pressure in the high-pressure side space exceeds the first predetermined value. In the pressure reducing valve according to any one of claims 1 to 3,
The stopper member is formed of a brittle material, and is ruptured by the pressing force when the pressure in the high-pressure side space exceeds the first predetermined value. In the pressure reducing valve according to any one of claims 1 to 3,
The pressure-reducing valve, wherein the stopper member is made of an elastic material and elastically deforms by the pressing force through the piston when the pressure in the high-pressure side space exceeds the first predetermined value. In the pressure reducing valve according to any one of claims 1 to 3,
The flow path forming means is a recess that is formed on an inner surface of a cylindrical portion that accommodates the piston as a part of the cylinder, and at least a part of which is enlarged in the circumferential direction of the cylindrical portion,
When the piston reaches the first predetermined position, the seal member reaches the recess, whereby a flow path from the high-pressure side space to the low-pressure side space is formed through the concave shape. Pressure reducing valve. In the pressure reducing valve according to any one of claims 1 to 3,
The flow path forming means is a protrusion that is formed on the inner surface of a cylindrical portion that accommodates the piston as a part of the cylinder, and that reduces the diameter of at least a portion of the cylindrical portion in the circumferential direction,
When the piston reaches the first predetermined position, the flow from the high pressure side space to the low pressure side space through the gap between the seal member and the cylinder formed by the seal member reaching the protrusion. A pressure reducing valve characterized in that a passage is formed. In the pressure reducing valve according to any one of claims 1 to 3,
The flow path forming means includes
A through-hole penetrating from the inside of the cylindrical portion accommodating the piston as a part of the cylinder to the outside of the pressure reducing valve,
When the piston reaches the first predetermined position, the seal member reaches the through hole, whereby a flow path from the high pressure side space to the outside of the pressure reducing valve is formed through the through hole. A pressure reducing valve.