JP2016041971A - Seal for high pressure gas - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance pressure resistance and sealing performance in a seal for high pressure gas for sealing the high pressure gas.SOLUTION: A seal for high pressure gas for sealing so that the high pressure gas is prevented from leaking from around a shaft inserted into a shaft hole of a casing includes a first stage seal part on a high pressure side and a second stage seal part on a low pressure side. The first stage seal part on the high pressure side includes a middle rigidity resin ring slidably abuts a peripheral surface of the shaft, a rubber ring arranged on an outer peripheral side of the middle rigidity resin ring, a middle rigidity resin backup ring disposed on the low pressure side of the middle rigidity resin ring and the rubber ring, and a high rigidity resin backup ring disposed on the low pressure side of the middle rigidity resin backup ring. The second stage seal part on the low pressure side includes a low rigidity resin ring slidably abuts the peripheral surface of the shaft, and a rubber ring arranged on an outer peripheral side of the low rigidity resin ring.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a high-pressure gas seal used for sealing high-pressure gas. The high-pressure gas seal of the present invention is used for, for example, a shaft sliding portion in a valve device (a pressure reducing valve, an on-off valve, or the like). The high-pressure gas seal of the present invention is used, for example, in the field of fuel cell parts (tanks, valves, etc.) or in other high-pressure seal fields.

  The higher the pressure of the hydrogen tank of the fuel cell vehicle, the longer the travel distance and the smaller the tank. On the other hand, the higher the pressure, the easier the gas leakage occurs in the flow path system. Therefore, for example, in the case of sealing with only the rubber packing 51 as shown in FIG. 2, there is a concern that gas leaks around the operating shaft 52.

JP 2008-299699 A

  In view of the above, an object of the present invention is to provide a high-pressure gas seal that can enhance the pressure resistance and the sealing performance of a high-pressure gas seal that seals high-pressure gas.

  To achieve the above object, a high-pressure gas seal according to claim 1 of the present invention is a high-pressure gas seal that seals high-pressure gas from leaking around a shaft that is inserted into a shaft hole of a housing. A high-pressure side first-stage seal portion and a low-pressure-side second-stage seal portion, and the high-pressure side first-stage seal portion is slidably in contact with the peripheral surface of the shaft; A rubber ring disposed on the outer peripheral side of the medium-rigid resin ring, a medium-rigid resin backup ring disposed on the low-pressure side of the medium-rigid resin ring and the rubber ring, and the medium-rigid resin backup A low-rigidity resin backup ring disposed on the low-pressure side of the ring, and the second-stage seal portion on the low-pressure side slidably contacts the peripheral surface of the shaft; The outer peripheral side of the low-rigidity resin ring And having a deployed are rubber rings.

  The high-pressure gas seal according to claim 2 of the present invention is the high-pressure gas seal according to claim 1, wherein the high-rigidity resin is a resin having higher rigidity than the medium-rigidity resin, and the low-rigidity resin. Is a resin having a lower rigidity than the medium-rigid resin.

  The high-pressure gas seal according to claim 3 of the present invention is the high-pressure gas seal according to claim 1 or 2, wherein the medium-rigid resin is a resin mainly composed of a PTFE material having a compression elastic modulus of 600 MPa or more. The high-rigidity resin is a resin whose main material is polyamide 46 or polyamide 66, and the low-rigidity resin is a resin whose main material is a PTFE material having a compression elastic modulus of 300 MPa or more and 600 MPa or less. And

  Furthermore, the high pressure gas seal according to claim 4 of the present invention is the high pressure gas seal according to claim 1, 2 or 3, wherein the first stage seal portion on the high pressure side and the second stage seal on the low pressure side. It has the flow path which opens or collects the pressure accumulated in the intermediate chamber between the parts.

  The high-pressure gas seal of the present invention having the above-described configuration sets a two-stage seal mechanism including a high-pressure side first-stage seal portion and a low-pressure-side second-stage seal portion around an axis, By providing the high pressure side first-stage seal part with excellent pressure resistance and the low pressure side second stage seal part having excellent sealing performance, A high-pressure gas seal having both of them can be configured. The specific configuration is as follows.

  That is, as the first-stage seal portion on the high-pressure side, a medium-rigid resin ring that slidably contacts the peripheral surface of the shaft, a rubber ring that is disposed on the outer peripheral side of the medium-rigid resin ring, and these Four rings consisting of a medium-rigid resin backup ring arranged on the low-pressure side of the medium-rigid resin ring and the rubber ring and a high-rigidity resin backup ring arranged on the low-pressure side of the medium-rigid resin backup ring Combine. On the other hand, the low-pressure side second-stage seal portion includes a low-rigidity resin ring that slidably contacts the peripheral surface of the shaft, and a rubber ring that is disposed on the outer peripheral side of the low-rigidity resin ring. Combine two rings.

  Here, the medium-rigid resin, the high-rigid resin, and the low-rigid resin indicate a relative hardness difference between the ring resin materials. That is, the high-rigid resin is a resin having higher rigidity than the medium-rigid resin. Refers to a resin having a lower rigidity than a medium-rigid resin.

  Therefore, in the first-stage seal portion on the high-pressure side, a ring made of a medium-rigid resin is used as a main seal ring, and the space between the main seal ring and the casing is sealed with a rubber ring. At the same time, the seal ring and rubber ring are strongly backed up by the medium-rigid resin backup ring and high-rigidity resin backup ring, so that excessive deformation of the seal ring and rubber ring is suppressed. Pressure resistance is demonstrated. As the medium-rigid resin, a resin mainly composed of a PTFE material having a compression modulus of 600 MPa or more is used, and as the high-rigidity resin, a resin mainly composed of polyamide 46 or polyamide 66 is preferably used. According to the resin material, it is possible to ensure necessary and sufficient pressure resistance.

  In the second-stage seal part on the low-pressure side, the seal pressure has already been reduced in the first-stage seal part on the high-pressure side, so a ring made of low-rigidity resin can be used as the main seal ring, The material can be selected from the standpoint of good sealing performance regardless of pressure resistance. Specifically, as the low-rigidity resin, it is preferable to use a resin mainly composed of a PTFE material having a compression elastic modulus of 300 MPa or more and 600 MPa or less. According to this resin material, a necessary and sufficient sealing property is ensured. Is possible.

  In the seal of the present invention, as described above, the high pressure side first stage seal part and the low pressure side second stage seal part are arranged in the axial direction, so that an intermediate chamber is set between the both seal parts. There is a concern that a pressure accumulation phenomenon in which pressure is gradually accumulated in the chamber occurs, and that this pressure accumulation affects the operation of the seal and the operation of the device incorporating the seal. Therefore, in order to prevent this, it is preferable to eliminate the pressure accumulation state by providing a mechanism for releasing or collecting the accumulated pressure accumulated in the intermediate chamber. Therefore, in the present invention, the accumulated pressure accumulated in the intermediate chamber is released or collected. It was decided to provide a flow path. The flow path is a weep hole or connected to an explosion-proof valve or the like.

  The present invention has the following effects.

  That is, in the present invention, as described above, a two-stage seal mechanism including a high-pressure side first-stage seal portion and a low-pressure-side second-stage seal portion is set around the shaft. A high-pressure gas seal that has both pressure resistance and sealing performance is provided by setting excellent pressure resistance in the first-stage seal portion and setting excellent sealability in the second-stage seal portion on the low-pressure side. be able to.

Sectional drawing of an apparatus housing | casing provided with the seal | sticker for high pressure gas which concerns on the Example of this invention Sectional drawing of an apparatus housing | casing provided with the seal | sticker which concerns on a prior art example

The present invention includes the following embodiments.
(1) The higher the pressure of the hydrogen tank of the fuel cell vehicle, the longer the cruising range and the smaller the tank can be. However, when hydrogen gas is supplied from the high-pressure fuel tank to the stack, multiple pressure reductions are required. A decompression system using a valve may be required. When a plurality of pressure reducing valves are used, it is preferable that the number of pressure reducing valves is small because it affects the space expansion and cost increase of the pressure reducing system unit.
(2) In a pressure reducing valve that can adjust the flow rate when the piston (shaft) slides in the axial direction and the piston comes into contact with the valve body, durability and sealing are achieved by using multiple seal parts for the piston. It was thought that a pressure reducing valve that achieved both characteristics could be realized. The seal part uses a combination of a rubber seal and a resin ring, and the high pressure side emphasizes durability. Therefore, the seal part of the high rigidity (medium rigidity) resin ring and the medium rigidity and high rigidity. Place two or more plastic backup rings. Leakage from the high-pressure side can be ensured by installing a sealing part of a resin ring with low rigidity that places importance on sealing performance. The present invention is characterized by a seal structure using seal parts of resin rings having different rigidity as described above. Since the pressure is accumulated between the seals, a system that can be opened with a pressure reducing valve or the like when the specified pressure is exceeded, or a gas that can be recovered and reused is desirable.
(3) According to the present invention, because of the above structure, the pressure reducing system is reduced to a single pressure reducing step from a two-stage (multi-stage) pressure reduction. It is.

  Next, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows a cross section of a casing portion of a pressure reducing valve device including a high-pressure gas seal according to an embodiment of the present invention. The pressure reducing valve device is connected to a piping part of a hydrogen gas supply system in the fuel cell.

The pressure reducing valve device is configured such that a shaft (also referred to as a piston or a shaft) 7 inserted through a housing (also referred to as a valve case) 1 slides in an axial direction (vertical direction in the drawing) and is brought into contact with the valve body 4 to thereby provide a flow rate. a type of pressure reducing valve for adjusting, also detects the stack pressure (secondary pressure) P ₂ sensor (not shown), (not shown) a solenoid connected to the upper shaft 7 to duty control the the tank pressure (primary pressure) P ₁ by a type of pressure reducing valve for reducing the pressure.

The housing 1, an input port 2 for inputting the tank pressure P _1, the valve chamber 3, and are provided the output port 5 for outputting the stack pressure P _2, the shaft hole 6 is provided so as to communicate the valve chamber 3, A shaft 7 as a valve body is inserted into the shaft hole 6 so that the hydrogen gas flowing in the valve does not leak to the outside from the gap between the shaft 7 and the inner peripheral surface of the shaft hole 6 around the shaft 7. A high-pressure gas seal is installed.

  The high-pressure gas seal 11 has a first-stage seal portion 21 on the high-pressure side arranged closer to the valve chamber 3 and a second-stage seal portion 31 on the low-pressure side arranged farther from the valve chamber 3. doing.

  The high-pressure side first-stage seal portion 21 includes a medium-rigid resin ring 22 that is slidably in contact with the peripheral surface of the shaft 7, and a rubber ring 23 disposed on the outer peripheral side of the medium-rigid resin ring 22. The medium-rigid resin backup ring 24 disposed on the low-pressure side of the medium-rigid resin ring 22 and the rubber ring 23 and the high-rigidity resin backup ring 25 disposed on the lower-pressure side of the medium-rigid resin backup ring 24. These four rings are incorporated in a first chamber 8 for assembling a seal provided on the inner peripheral surface of the shaft hole 6.

  Each of the medium-rigid resin ring 22 and the medium-rigid resin backup ring 24 is formed of a predetermined resin material, and specifically, a PTFE material having a compression modulus of 600 MPa or more (for example, carbon / graphite filling or carbon fiber filling). Is molded by. The high-rigidity resin backup ring 25 is formed of a resin material having a hardness higher than that of the medium-rigidity resin ring 22 and the medium-rigidity resin backup ring 24. Specifically, the polyamide 46 or the polyamide 66 (these are made of glass). (Including the case of filling and reinforcing with fibers and the like).

  On the other hand, the second-stage seal portion 31 on the low pressure side includes a low-rigidity resin ring 32 that is slidably in contact with the peripheral surface of the shaft 7, and a rubber ring disposed on the outer peripheral side of the low-rigidity resin ring 32. 33, and these two rings are incorporated in a second chamber 9 for assembling a seal provided on the inner peripheral surface of the shaft hole 6.

  The low-rigidity resin ring 32 is formed of a resin material having a lower hardness than the medium-rigidity resin ring 22 and the medium-rigidity resin backup ring 24. Specifically, the low-rigidity resin ring 32 has a compression elastic modulus of 300 MPa to 600 MPa (or less). Molded with PTFE material.

  Further, an intermediate chamber 10 is provided between the first-stage seal portion 21 on the high-pressure side and the second-stage seal portion 31 on the low-pressure side, and a flow path 41 that opens to the intermediate chamber 10 is provided. 41 is provided in order to release or recover the accumulated pressure accumulated in the intermediate chamber 10.

  The pressure reducing valve device configured as described above adjusts the pressure according to the lift amount of the shaft 7 as described above, and high-pressure hydrogen gas flows from the input port 2 toward the valve chamber 3. A two-stage seal 11 comprising a combination of a first-stage seal portion 21 on the side and a second-stage seal portion 31 on the low-pressure side is provided, and the first-stage seal portion 21 on the high-pressure side is excellent based on its component configuration On the other hand, the second-stage sealing portion 31 on the low-pressure side exhibits excellent sealing performance based on the component configuration. Therefore, it is possible to provide the high-pressure gas seal 11 that exhibits sufficient performance in both pressure resistance and sealing performance.

  In addition, a flow path 41 that opens to the intermediate chamber 10 between the high-pressure side first-stage seal portion 21 and the low-pressure side second-stage seal portion 31 is provided, and the accumulated pressure in the intermediate chamber 10 is released or recovered from the flow path 41. Therefore, it is possible to prevent the accumulated pressure from affecting the operation of the seal 11 and the operation of the pressure reducing valve device.

  In the above embodiment, the device for assembling the high-pressure gas seal 11 is a pressure reducing valve device, but this is merely an example. Therefore, the apparatus for assembling the high-pressure gas seal 11 may be another type of apparatus, and is not particularly limited. The number of backup rings installed is two consisting of the medium-rigid resin backup ring 24 and the high-rigidity resin backup ring 25, but may be three or more.

DESCRIPTION OF SYMBOLS 1 Housing | casing 2 Input port 3 Valve chamber 4 Valve body 5 Output port 6 Shaft hole 7 Shaft 8 1st chamber 9 2nd chamber 10 Intermediate chamber 21 First stage seal part 22 Medium-rigid resin ring 23, 33 Rubber ring 24 Medium-rigidity resin backup ring 25 High-rigidity resin backup ring 31 Second stage seal 32 Low-rigidity resin ring 41 Flow path

Claims (4)

A high-pressure gas seal that seals high-pressure gas from leaking around a shaft that is inserted into a shaft hole of a housing, and includes a high-pressure side first-stage seal portion and a low-pressure-side second-stage seal portion. ,
The high-pressure side first-stage seal portion includes a medium-rigid resin ring that slidably contacts the peripheral surface of the shaft, a rubber ring that is disposed on the outer peripheral side of the medium-rigid resin ring, A medium-rigid resin backup ring disposed on the low-pressure side of the rigid resin ring and rubber ring, and a high-rigidity resin backup ring disposed on the low-pressure side of the medium-rigid resin backup ring,
The second-stage seal portion on the low-pressure side has a low-rigidity resin ring that slidably contacts the peripheral surface of the shaft, and a rubber ring that is disposed on the outer peripheral side of the low-rigidity resin ring. High-pressure gas seal characterized by The high-pressure gas seal according to claim 1,
The high-rigidity resin is a resin having higher rigidity than the medium-rigidity resin,
The high-pressure gas seal is characterized in that the low-rigidity resin is a resin having lower rigidity than the medium-rigidity resin. The high-pressure gas seal according to claim 1 or 2,
The medium-rigid resin is a resin mainly composed of a PTFE material having a compression elastic modulus of 600 MPa or more,
The high-rigidity resin is a resin mainly composed of polyamide 46 or polyamide 66,
The low-rigidity resin is a high-pressure gas seal characterized in that it is a resin mainly composed of a PTFE material having a compression modulus of 300 MPa or more and 600 MPa or less. The high-pressure gas seal according to claim 1, 2 or 3,
A high-pressure gas seal comprising a flow path for releasing or collecting accumulated pressure accumulated in an intermediate chamber between the first-stage seal portion on the high-pressure side and the second-stage seal portion on the low-pressure side.

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