JP5561864B2 - Pressure reducing device for fuel cell system and bellows used therefor - Google Patents

Description

  The present invention relates to a decompression device for a fuel cell system and a bellows used therefor, and more particularly to a decompression device used for decompressing high-pressure hydrogen gas having a primary pressure of 100 MPa or more and a bellows used therefor.

When it is desired to use a high fluid pressure (primary pressure) at a lower pressure, for example, a pressure reducing valve as shown in FIG. 8 is used.
This pressure reducing valve is seated on a valve seat 200 provided in the middle of a path from a primary side port that becomes a high pressure (tank original pressure) P1 to a secondary side port that becomes a low pressure (control pressure) P2. The valve body 110 which closes a valve and opens a valve by leaving | separating from the valve seat 200 is provided. The valve body 110 includes a shaft portion 112 and a valve main body portion 111 provided at the tip of the shaft portion 112. The shaft portion 112 is disposed so as to be able to reciprocate within a through hole 301 of the housing 300, one of which is in the path and is upstream of the valve seat 200. As the shaft 112 reciprocates, the valve is opened and closed. The other end of the through hole 301 communicates with a region where the atmospheric pressure P3 is reached. The sliding portion between the valve body 110, which is a movable component, and the housing 300, which is a stationary component, has a fluid in the upstream region R. Therefore, it is necessary to seal the annular gap between the shaft portion 112 and the through hole 301 so as not to leak through the through hole 301.

Therefore, conventionally, a seal ring 400 such as an O-ring is provided to seal the annular gap (hereinafter referred to as “Prior Art 1”, for example, see Patent Document 1). Thereby, even when the valve body 110 reciprocates, the outer peripheral surface of the shaft part 112 and the inner peripheral surface of the seal ring 400 slide, and the sealing performance can be maintained.
However, in the case of the prior art 1, when the primary side pressure is extremely high and the differential pressure between the primary side pressure P1 and the atmospheric pressure P3 becomes very large, the frictional force between the shaft portion 112 and the seal ring 400 is also very high. Become bigger. For this reason, there is a problem that the pressure adjustment function as a pressure reducing valve is lowered due to an increase in hysteris and the sliding portion is fixed, and the solenoid for driving the valve body 110 must be enlarged.

Further, conventionally, there is known a method in which an elastic pressure partition is formed by a diaphragm formed of a rubber film or the like, or a metal bellows and the like, and the movable part and the fixed part are sealed (hereinafter referred to as “prior art”). 2 ”(for example, see Patent Document 2).
However, the diaphragm or the metal bellows in the prior art 2 has a low pressure resistance, and cannot be used at the primary side pressure.

Further, conventionally, a bellows formed by combining metals of different materials such as a combination of a metal material having excellent spring properties and a metal material having excellent corrosion resistance is known (hereinafter referred to as “Prior Art 3”). (For example, see Patent Document 3). )
However, in the case of the prior art 3, by combining double and triple metals of different materials, a bellows having different characteristics such as springiness and corrosion resistance at the same time is provided. It was not supposed to be used at a high pressure of 100 MPa or more like the primary side of the hydrogen gas pressure reducing valve.

  By the way, in the bellows used for the high pressure control valve, it is necessary to increase the plate thickness of the bellows in order to ensure the pressure resistance strength. However, if the plate thickness is thick, the bellows cannot be easily expanded and contracted, for example, reduced pressure driven by electromagnetic force. When used for a valve or the like, there is a problem that the thrust of the electromagnetic valve needs to be increased and the apparatus becomes large. In addition, a thick bellows has a problem that its durability life is short.

JP 2007-148465 A JP 2005-309983 A Microfilm of Japanese Utility Model No. 56-98575 (Japanese Utility Model Publication No. 58-4848)

The present invention has been made to solve the above-described problems of the prior art. First, in a decompression device used for decompression of high-pressure hydrogen gas having a primary pressure of 100 MPa or more, An object of the present invention is to provide a decompression device for a fuel cell system in which thrust is made as small as possible.
In addition, the present invention secondly provides a bellows used in a pressure reducing device for a fuel cell system that has both pressure resistance against a high-pressure working fluid of 100 MPa or more and ease of expansion and contraction that facilitates movement of a valve body. It is intended to provide.

  In order to achieve the above-described object, a decompression device for a fuel cell system according to the present invention has a valve seat in the middle of a path that connects a high-pressure primary port and a low-pressure secondary port, and faces the valve seat. A through hole is provided on the opposite side, and a valve body that opens and closes the path by being attached to and detached from the valve seat is provided. A transmission member that applies force to the valve body is provided, a sealing member is provided between the rear end side of the valve body and the through hole, and the sealing member is formed of a multilayer molded bellows made of a metal material. It is characterized by.

  With the above-described features, it is possible to provide a decompressor for a fuel cell system in which a thrust of a solenoid valve is made as small as possible in a decompressor used for decompressing high-pressure hydrogen gas having a primary pressure of 100 MPa or more.

In the bellows used in the decompression device for a fuel cell system according to the present invention, first, the cross-sectional shape of the bellows portion of the multilayer molded bellows is alternately connected to peaks and valleys having a shape less than a semicircle. It is characterized by its shape.
The bellows used in the decompression device for a fuel cell system according to the present invention is secondly characterized in that a straight portion is interposed between a crest and a trough having a shape less than the semicircle.
With these characteristics, it is possible to obtain a high-pressure control valve bellows that simultaneously has pressure resistance against a high-pressure working fluid and ease of expansion and contraction that facilitates movement of the valve element. Moreover, the high-pressure control valve bellows having a long durability life can be obtained. Furthermore, compared to the case where an O-ring is used, there is no leakage of the sliding part, and there is no increase or sticking of hysteresis due to the frictional force of the sliding part. Bellows can be provided.

The bellows used in the decompression device for a fuel cell system according to the present invention is thirdly characterized in that, in the first or second feature, a plurality of bellows are connected in series via a holding member. .
Due to this feature, the bellows can be easily manufactured as compared with the case of manufacturing a long bellows.

The present invention has the following excellent effects.
(1) In the decompression device for a fuel cell system of the present invention, a valve member is provided with a transmission member that acts on the valve body in the axial direction of a bellows that receives pressure on the solenoid and the secondary side on the distal end side of the valve body. By providing a sealing member between the rear end side and the through hole, and forming the sealing member from a multilayer molded bellows made of a metal material, the pressure on the primary side is reduced to 100 MPa or higher. Even when used in the above, it is possible to provide a decompressor for a fuel cell system in which the thrust of the electromagnetic valve is made as small as possible.

(2) The bellows used in the pressure reducing device for a fuel cell system according to the present invention has a shape in which the cross-sectional shape of the bellows portion of the multilayer molded bellows is alternately connected to peaks and valleys having a shape less than a semicircle. Thus, it is possible to obtain a high-pressure control valve bellows that simultaneously has pressure resistance against a high-pressure working fluid and ease of expansion and contraction that facilitates movement of the valve element. Moreover, the high-pressure control valve bellows having a long durability life can be obtained. Furthermore, compared to the case where an O-ring is used, there is no leakage of the sliding part, and there is no increase or sticking of hysteresis due to the frictional force of the sliding part. Bellows can be provided.
Moreover, the bellows used for the decompression device for a fuel cell system of the present invention has a peak portion and a valley portion by interposing a straight portion between the peak portion and the valley portion having a shape less than the semicircle. It can be connected smoothly.

(3) The bellows used in the pressure reducing device for a fuel cell system according to the present invention can be manufactured more easily than a long bellows by connecting a plurality of bellows in series via a holding member. Can be.

It is sectional drawing which shows the whole decompression device for fuel cell systems which concerns on Embodiment 1 of this invention. It is an expanded sectional view of the bellows used for Embodiment 1 of the present invention. It is sectional drawing which shows the whole pressure reduction apparatus for fuel cell systems which concerns on Embodiment 2 of this invention. It is sectional drawing which shows the whole pressure reduction apparatus for fuel cell systems which concerns on Embodiment 3 of this invention. It is sectional drawing which shows the whole pressure reduction apparatus for fuel cell systems which concerns on Embodiment 4 of this invention. It is sectional drawing which shows the whole pressure reduction apparatus for fuel cell systems which concerns on Embodiment 5 of this invention. It is an expanded sectional view of the bellows used for Embodiment 5 of the present invention. It is a schematic diagram explaining the prior art 1. FIG.

  DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments for carrying out a decompression device for a fuel cell system and a bellows used therein according to the present invention will be described in detail with reference to the drawings, but the present invention is not construed as being limited thereto. Various changes, modifications, and improvements can be made based on the knowledge of those skilled in the art without departing from the scope of the above.

Embodiment 1
FIG. 1 is a cross-sectional view showing the entire decompression device for a fuel cell system according to Embodiment 1 of the present invention.
In Embodiment 1 of FIG. 1, a decompression valve for decompressing a high-pressure hydrogen gas of 100 MPa or more is shown as a decompression device 1 for a fuel cell system, and a housing 2 includes a primary port 3 that becomes a high pressure P1, a low pressure A secondary side port 4 serving as P2 and a path 5 communicating the primary side port 3 and the secondary side port 4 are formed. A circular valve seat 6 is provided in the middle of the path 5, and a valve body 7 is provided that is closed when seated on the circular valve seat 6 and opened when the valve seat 6 is left.

  The valve body 7 includes a shaft portion 8 and a valve main body portion 9 provided on the distal end side of the shaft portion 8. The shaft portion 8 of the valve body 7 is disposed so as to be reciprocally movable in a through hole 10 in which one communicates with the path 5 between the primary port 3 and the secondary port 4 and the other communicates with the atmospheric pressure region A. Yes.

  On the other hand, a solenoid 11 is mounted on one side of the housing 2 by a fixing means such as a bolt. The solenoid 11 is fixed to a coil 12, a substantially cylindrical center post 13 made of a magnetic material, a plunger 14 that is magnetically attracted by energization of the coil 12 and moves toward the center post 13, and the plunger 14. Rod 15 is provided. The rod 15 is provided so as to be inserted through a through hole provided in the center of the center post 13, and a tip of the rod 15 is disposed on a bellows 16 serving as a pressure receiving member disposed at a position for receiving the secondary pressure P <b> 2. It is fixed through.

A projecting portion 17 projecting from the holding member 18 toward the valve body 7 is in contact with the distal end side of the valve body 7, and this projecting portion 17 is formed of a bellows 16 as a pressure receiving member that receives the pressure P <b> 2 on the secondary side. The holding member 18 is integrally provided. For this reason, the valve body 7 can receive the thrust F toward the rear end side (left side in FIG. 1) from the solenoid 11 as will be described later. Further, a spring 19 is provided at the rear end of the valve body 7 (rear end of the shaft portion 8) to bias the valve body 7 toward the front end side.
In the present embodiment, the projecting portion 17 serves as a transmission member that transmits the axial force of the solenoid 11 and the bellows 16 to the valve body 7.

A bellows 20 as an elastic pressure bulkhead for sealing a fluid in a path 5 communicating the primary side port 3 and the secondary side port 4 so as not to leak into the atmospheric pressure region A through the through hole 10 is a valve body. 7 and a seal guide 21 having a through hole 10 formed therein. The primary pressure P1 acts on the outside of the bellows 20, and the atmospheric pressure P3 acts on the inside.
Although an example in which the atmospheric pressure P3 acts on the atmospheric pressure region A has been described, in the unlikely event that the bellows is damaged and high-pressure hydrogen does not leak into the atmosphere, the pressurized gas is applied to the atmospheric pressure region A. You may make it act.
In the example shown in FIG. 1, the sealing bellows 20 is arranged so as to surround the periphery of the shaft portion 8 of the valve body 7, and the right end thereof is airtightly fixed to the rear end side of the valve body portion 9 by welding or the like. The left end is airtightly fixed to the holding portion 22 of the seal guide 21 by welding or the like.
Further, the diameter D1 of the circle that is the pressure receiving region of the valve body 7 and the average diameter D2 of the outer diameter and the inner diameter of the bellows 20 are set to be equal. That is, by making the pressure receiving area of the valve body 7 equal to the pressure receiving area of the bellows 20, the axial force of the primary pressure P <b> 1 against the bellows 20 is canceled, and only the radial pressure acts on the bellows 20. become.

In the fuel cell system decompression device 1 configured as described above, the operation of the valve body 7 is controlled by the pressure (control pressure) P2 and the thrust F received by the bellows 16, and as a result, the opening and closing of the valve is controlled. . For this reason, the control pressure P2 can be controlled.
Specifically, the force acting on the valve body 7 is the force acting on the valve body 7 when the pressure P1 on the primary side, the pressure P2 on the secondary side, the atmospheric pressure P3, and the bellows 16 receive the pressure P2. The thrust F, the elastic restoring force of the sealing bellows 20, and the spring force of the spring 19. Therefore, the position of the valve body 7 is determined by the balance of these forces. In order to control the secondary pressure P2 to a desired pressure with respect to the primary pressure P1, the characteristics of the bellows 16, the thrust F, the spring constant of the sealing bellows 20, and the spring constant of the spring 19 are appropriately set. do it.

By the way, since the pressure P1 on the primary side is a very high pressure of 100 MPa or more, the sealing bellows 20 receives a high pressure from the surroundings, and therefore needs to have pressure resistance (rigidity) to withstand this force. At the same time, when the valve body 7 is moved in response to a force such as a thrust F, it is necessary to have elasticity for facilitating the movement of the valve body 7.
In terms of pressure resistance, it is necessary to increase the thickness t of the bellows 20 for sealing, but if the thickness t is increased, the spring constant increases in proportion to the cube of the thickness t, and the elasticity is hindered. However, there is a background that the required items cannot be satisfied at the same time, for example, the durability life is reduced.
The present inventor has obtained that the spring constant is proportional to the cube of the thickness t, and the pressure resistance is the same if the entire bellows thickness is the same. By making the bellows 20 into a multilayer structure in which a plurality of molded bellows made of a metal material are combined, and by devising the cross-sectional shape of the bellows part, both pressure resistance and stretchability can be satisfied simultaneously. I got the knowledge.

FIG. 2 is a cross-sectional view illustrating a bellows used in the fuel cell system pressure reducing valve according to Embodiment 1 of the present invention.
The sealing bellows 20 has a three-layer structure in which an outer peripheral side molded bellows 20-1, an intermediate molded bellows 20-2 and an inner peripheral side molded bellows 20-3 made of a stainless material (SUS304) are overlapped. Since the total thickness of the three layers is t, and the thickness of each layer is set to be the same, the thickness of the one-layer molded bellows is t / 3. If the spring constant of one layer is k, the spring constant k _T of the bellows 20 having a three-layer structure is
k _T = k + k + k = 3k, and the spring constant can be greatly reduced as compared with the bellows having the same thickness of the single-layer structure.
On the other hand, the pressure resistance (stress) has the same pressure resistance regardless of whether it is a single layer or a multilayer, as long as the thickness t is the same.

Next, in order to endure a high pressure of 100 MPa or more, the inventor paid attention to the cross-sectional shape of the bellows part and tested the cross-sectional shape in various ways. As a result, the conventionally known U-shape and inverted U-shape were obtained. It has been found that the bellows shape that is connected alternately or the bellows shape that is a combination of S-shapes is crushed mainly in the axial direction due to high pressure.
The cross-sectional shape of the bellows portion of the multilayer molded bellows shown in FIG. 2 is a shape in which peaks and valleys having a shape less than a semicircle are alternately connected, and it was confirmed that the bellows portion is not easily crushed in the axial direction.
Here, the shape less than a semicircle means that the upper limit is less than a semicircle (circumference angle less than 180 °), and the lower limit has at least an arc component. For example, 1/12 of a circle (circumference angle 30 °) It is.
How many times the circumferential angle is set can be determined based on the bellows outer diameter, bellows thickness, peak height (or valley height), pitch, radius of curvature of peak (or valley), etc. .
Moreover, when connecting the peak part and trough part of a shape less than a semicircle alternately, a straight part may be interposed between this peak part and trough part. In this case, the straight part is oriented not in the direction perpendicular to the axial direction of the bellows but in the oblique direction having a constant angle θ with the axial direction of the bellows in order to smoothly connect peaks and valleys having a shape less than a semicircle. It becomes.

The decompression device for a fuel cell system according to the first embodiment uses a multilayer bellows having pressure resistance and a relatively small spring constant, so that the decompression device operates reliably even if the thrust of the solenoid valve is small. can do.
Moreover, since the bellows used for the decompression device for the fuel cell system according to Embodiment 1 has a shape in which the cross-sectional shape of the bellows portion is a shape in which the peaks and valleys having a shape less than a semicircle are alternately connected, Both pressure resistance and stretchability are satisfied at the same time.

[Embodiment 2]
FIG. 3 is a cross-sectional view showing the entire decompression device for a fuel cell system according to Embodiment 2 of the present invention.
The pressure reducing device shown in FIG. 3 has the basic configuration of the pressure reducing device described in FIG. 1, and the same components are denoted by the same reference numerals, and the description thereof is omitted as appropriate.

The valve body 25 includes a valve main body portion 26 and a transmission member 27 that is provided on the distal end side of the valve body 25 and transmits the axial force of the solenoid 11 and the bellows 16 to the valve body 25. The shaft portion 8 is omitted.
The transmission member 27 is fitted and coupled to a holding member 28 of a bellows 16 as a pressure receiving member disposed at a position where the transmission member 27 receives a pressure P2 on the secondary side.

The sealing bellows 20 is provided between the rear end side of the valve body 25 and the seal guide 21 in which the through hole 10 is drilled, and the right end thereof is welded to the rear end side of the valve body portion 26. Etc., and the left end is airtightly fixed to the holding portion 22 of the seal guide 21 by welding or the like.
A fixing member 29 for pressing and fixing the seal guide 21 is provided on the rear end side of the seal guide 21, and the fixing member 29 is screwed into the hole 30 of the housing 2.
The fixing member 29 is provided with a communication hole 31 for communicating the through hole 10 with the atmospheric pressure region A. The primary pressure P1 acts on the outside of the bellows 20, and the atmospheric pressure P3 acts on the inside.

  In the fuel cell system decompression device 1 configured as described above, the operation of the valve body 25 is controlled by the pressure (control pressure) P2 and the thrust F received by the bellows 16, and as a result, the opening and closing of the valve is controlled. . For this reason, the control pressure P2 can be controlled. Specifically, the force acting on the valve body 25 is the force acting on the valve body 25 when the pressure P1 on the primary side, the pressure P2 on the secondary side, the atmospheric pressure P3, and the bellows 16 receive the pressure P2. And the thrust F and the elastic restoring force of the sealing bellows 20. Therefore, the position of the valve body 25 is determined by the balance of these forces. In order to control the secondary pressure P2 to a desired pressure with respect to the primary pressure P1, the characteristics of the bellows 16, the thrust F, and the spring constant of the sealing bellows 20 may be set as appropriate.

[Embodiment 3]
FIG. 4 is a cross-sectional view showing the entire decompression device for a fuel cell system according to Embodiment 3 of the present invention.
The pressure reducing device shown in FIG. 4 includes the basic configuration of the pressure reducing device described in FIG. 1, and the same components are denoted by the same reference numerals, and the description thereof is omitted as appropriate.

  In the decompression device 1 according to the third embodiment, the region provided with the spring 19 provided on the rear end side of the through hole 10 is blocked from the atmospheric pressure region, and the passage 32 connected to the secondary port P2 is provided. It has been. As a result, the pressure in the region where the spring 19 on the rear end side of the through hole 10 is provided becomes equal to the pressure P2 on the secondary side. For this reason, the pressure P2 on the secondary side acts on the inside of the bellows 20 to exert a force in the direction in which the bellows 20 is extended. On the other hand, the pressure P2 on the secondary side acts on the valve body 7 with respect to the diameter D1 of the circle as the pressure receiving region, and a force acts in the direction of contracting the bellows 20, so the pressure P2 on the secondary side is offset. The valve body 7 is operated only by the solenoid force. In this manner, the valve body 7 can be stably opened and closed even if the pressure on the secondary side fluctuates without being substantially affected by the pressure P2 on the secondary side.

[Embodiment 4]
FIG. 5 is a cross-sectional view showing the entire decompression device for a fuel cell system according to Embodiment 4 of the present invention.
The pressure reducing device shown in FIG. 5 has the basic configuration of the pressure reducing device described in FIG. 3, and the same components are denoted by the same reference numerals, and the description thereof is omitted as appropriate.

  In the decompression device 1 according to the fourth embodiment, the region of the hole 30 provided with the fixing member 29 for pressing and fixing the seal guide 21 is blocked from the atmospheric pressure region and connected to the secondary port P2. A passage 32 is provided. As a result, the pressure in the region of the hole 30 provided with the fixing member 29 on the rear end side of the through hole 10 becomes equal to the pressure P2 on the secondary side. For this reason, the pressure P2 on the secondary side acts on the inside of the bellows 20 to exert a force in the direction in which the bellows 20 is extended. On the other hand, the pressure P2 on the secondary side acts on the valve body 7 with respect to the diameter D1 of the circle as the pressure receiving region, and a force acts in the direction of contracting the bellows 20, so the pressure P2 on the secondary side is offset. The valve body 7 is operated only by the solenoid force. In this manner, the valve body 7 can be stably opened and closed even if the pressure on the secondary side fluctuates without being substantially affected by the pressure P2 on the secondary side.

[Embodiment 5]
FIG. 6 is a cross-sectional view showing the entire decompression device for a fuel cell system according to Embodiment 5 of the present invention.
The pressure reducing device shown in FIG. 6 has the basic configuration of the pressure reducing device described in FIG. 3, and the same components are denoted by the same reference numerals, and the description thereof is omitted as appropriate.

In the decompression device 1 according to the fifth embodiment, the housing 2 is provided with one primary port 3 that is the high pressure P1 on the upper side in the drawing and two secondary ports 4 that are the low pressure P2 on the upper and lower sides in the drawing. It has been. A spring 33 that urges the valve body 25 toward the distal end side is provided on the transmission member 27 provided on the distal end side of the valve main body portion 26.
The sealing bellows 35 is provided between the rear end side of the valve body 25 and the seal guide 21 in which the through hole 10 is drilled, and the right end thereof is welded to the rear end side of the valve body 26. Etc., and the left end is airtightly fixed to the holding portion 22 of the seal guide 21 by welding or the like. The primary pressure P1 acts on the outside of the bellows 35, and the atmospheric pressure P3 acts on the inside.

FIG. 7 is an enlarged cross-sectional view of a bellows used in Embodiment 5 of the present invention.
The sealing bellows 35 of the fifth embodiment is formed in a three-layer structure as in the first embodiment, but is divided into three equal lengths in the longitudinal direction, and each bellows is a holding member. It is connected via.
The right end of the right bellows 36 is press-fitted into the outer periphery of the rear end of the valve body 26, the left end is press-fitted into the right end of the holding member 39, and the respective press-fit ends are welded all around.
The central bellows 37 has a right end that is press-fitted into the left end of the holding member 39, a left end that is press-fitted into the right end of the holding member 40, and the respective press-fitting end portions are welded all around.
Further, the left bellows 38 is press-fitted at the right end into the left end of the holding member 40, the left end is press-fitted into the holding portion 22 of the seal guide 21 that is airtightly fixed to the housing 2, and the respective press-fit end portions are welded all around. ing.
A hole 41 is formed in the holding members 39 and 40.

As in the bellows 35 shown in the fifth embodiment, the spring constant ks when three are connected in series is k ₁ .
1 / ks = 1 / k ₁ + 1 / k ₁ + 1 / k ₁ = 3 / k ₁
ks = _k 1/3
Thus, since the spring constant is the same as that when one long bellows is provided, the spring constant does not increase.

  If the three bellows 35 are connected in series as in the sealing bellows 35 of the fifth embodiment, the length of one bellows can be shortened. Easy to manufacture.

DESCRIPTION OF SYMBOLS 1 Pressure reducing apparatus for fuel cell systems 2 Housing 3 Primary side port 4 Secondary side port 5 Path | route 6 Valve seat 7 Valve body (Embodiment 1 and 3)
8 Shaft 9 Valve body (Embodiments 1 and 3)
DESCRIPTION OF SYMBOLS 10 Through-hole 11 Solenoid 12 Coil 13 Center post 14 Plunger 15 Rod 16 Bellows 17 Protrusion part (transmission member)
18 Holding member (Embodiments 1 and 3)
19 Spring 20 Bellows (Embodiments 1 to 4)
21 Seal guide 22 Holding part 25 Valve body (Embodiments 2 and 4)
26 Valve body (Embodiments 2 and 4)
27 Transmission member (Embodiments 2 and 4)
28 Holding member (Embodiments 2 and 4)
29 fixed member 30 hole 31 communication hole 32 passage 33 spring 35 bellows (Embodiment 5)
36 right bellows 37 middle bellows 38 left bellows 39 holding member 40 holding member 41 hole A atmospheric pressure region F solenoid thrust P1 high pressure (primary pressure)
P2 Low pressure (secondary pressure)
P3 atmospheric pressure

Claims (4)

A valve seat is provided in the middle of the path connecting the high-pressure primary port and the low-pressure secondary port, and a through-hole leading to the atmospheric pressure region is provided on the opposite side of the valve seat. A valve body that opens and closes the path, and a transmission member that acts on the valve body in the axial direction of the solenoid and the bellows that receives the pressure on the secondary side is provided on the distal end side of the valve body, A sealing member is provided between the rear end side of the body and the through hole, and the sealing member is formed of a multilayer molded bellows made of the same metal material, and the pressure receiving area of the valve body and the molded bellows A pressure reducing device for a fuel cell system, characterized in that the pressure receiving area is set equal to the pressure receiving area .   The decompression device for a fuel cell system according to claim 1, wherein a cross-sectional shape of the bellows portion of the multilayer molded bellows is a shape in which peaks and valleys having a shape less than a semicircle are alternately connected. Bellows used.   The bellows used in the decompression device for a fuel cell system according to claim 2, wherein a straight portion is interposed between a peak portion and a valley portion having a shape less than the semicircle.   4. A bellows used in a decompression device for a fuel cell system according to claim 2, wherein a plurality of the multilayer molded bellows are connected in series via a holding member.

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