non-return valve

Abstract

To provide a check valve that can improve the responsiveness of valve opening operation.SOLUTION: A check valve 15 has a cylindrical housing 41 that has a lateral hole 41E penetrating a peripheral wall, a valve seat 42 provided at an axial end of the housing 41, and a valve element 43 that is received inside the housing 41 to be movable in an axial direction and is constantly urged to sit on the valve seat 42. By movement of the valve element 43 in a direction away from the valve seat 42, a first opening δ1 serving as a gas inlet and a second opening δ2 serving as a gas outlet are formed. The first opening δ1 is a gap between the valve seat 42 and the tip of the valve element 43, and is opened and closed by the tip of the valve element 43. The second opening δ2 is a part of the lateral hole 41E exposed inside the housing 41, and is opened and closed by the outer peripheral surface of the valve element 43. Regardless of the position of the valve element 43, the opening area of the second opening δ2 is configured to be narrower than the opening area of the first opening δ1.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a check valve.

Background Art

[0002] Conventionally, a valve device for controlling the supply and discharge of high-pressure hydrogen gas stored inside a gas tank is attached to a gas tank mounted on a fuel cell vehicle or the like. For example, the valve device of Patent Document 1 includes a body in which a gas flow path communicating the inside and outside of the gas tank is formed. The gas flow path includes a filling path for filling the gas tank with hydrogen gas supplied from an external supply source, for example, a hydrogen tank at a hydrogen station. A check valve for preventing the backflow of hydrogen gas is provided in the filling path.

[0003] During hydrogen gas filling, due to the pressure of the hydrogen gas supplied from the outside, the valve body separates from the valve seat against the biasing force of a biasing member such as a coil spring. As a result, the check valve is in an open state. The hydrogen gas passing through the open check valve is filled into the gas tank through the filling path. When the filling of hydrogen gas is completed, the valve body is biased by the pressure of the hydrogen gas inside the gas tank and the biasing force of the biasing member, so that the head of the valve body closes the valve hole of the valve seat. As a result, the check valve is in a closed state.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] For example, fuel cell vehicles are required to shorten the hydrogen gas filling time. The filling time is affected by the responsiveness of the opening operation of the check valve. In order to shorten the filling time, it is required to improve the responsiveness of the opening operation of the check valve. [Means for solving the problem]

[0006] A check valve capable of solving the above problems is provided in a gas flow path. The check valve includes a cylindrical housing having a transverse hole penetrating its peripheral wall, a valve seat provided at the axial end of the housing, and a valve body housed axially movable inside the housing and constantly biased to seat on the valve seat. The valve body is configured to form a first opening which serves as the gas inlet and a second opening which serves as the gas outlet by moving away from the valve seat. The first opening is the gap between the valve seat and the tip of the valve body, and is configured to be opened and closed by the tip of the valve body. The second opening is a part of the transverse hole exposed inside the housing, and is configured to be opened and closed by the outer circumferential surface of the valve body. Regardless of the position of the valve body, the opening area of ​​the second opening is configured to be smaller than the opening area of ​​the first opening.

[0007] In this configuration, as the gas passes through the second opening, the second opening acts as a throttling mechanism, causing a pressure loss in the gas. As a result, the gas pressure upstream of the second opening becomes higher than the gas pressure downstream of the second opening. Consequently, the gas supplied from the first opening flows smoothly into the lateral hole through the second opening, improving the responsiveness of the pressure reducing valve's opening operation.

[0008] In the above-described check valve, the tip of the valve body may have a tapered surface that narrows towards the tip. In this case, the valve body may be configured such that the tapered surface overlaps radially with respect to the lateral hole as it moves, thereby forming the second opening. Furthermore, when the valve body moves away from the valve seat, the first opening may be configured to open before the second opening.

[0009] In this configuration, when the first opening begins to open, the gas flows into the housing from the first opening while the second opening is closed, increasing the pressure-receiving area, which is the area of ​​the valve body that receives the gas pressure. As a result, the load acting on the valve body away from the valve seat increases. Therefore, the valve body can be smoothly moved away from the valve seat by the gas pressure. The valve body moves smoothly to a position where the tapered surface radially overlaps with the lateral hole, thereby properly opening the second opening.

[0010] In the above-described check valve, the size of the lateral hole may be set such that, during the period from when the second opening begins to form until the opening area of ​​the second opening reaches its maximum, the extended surface obtained by virtually extending the tapered surface does not intersect with the inner circumferential surface of the lateral hole.

[0011] In this configuration, the gas supplied from the first opening flows into the transverse hole through the second opening, guided by the tapered surface of the valve body. At this time, the gas flows into the transverse hole in a direction along the extension plane. The size of the transverse hole is set so that the extension plane does not intersect with the inner circumferential surface of the transverse hole during the period from when the second opening begins to form until the opening area of ​​the second opening is maximized. Therefore, the gas flowing into the transverse hole along the extension plane is prevented from hitting the inner circumferential surface of the transverse hole. Consequently, the gas flowing into the transverse hole can be allowed to flow out smoothly from the transverse hole.

[0012] In the above-described check valve, the gas that has passed through the second opening may be configured to be supplied to a gas tank. In this case, the pressure of the gas that has passed through the second opening may be configured to act on the base end, which is the end of the valve body opposite to the tip.

[0013] In this configuration, for example, when the gas tank is filled with gas and the gas supply from the gas source to the tank is stopped, the pressure on the primary side of the check valve and the pressure on the secondary side of the check valve become balanced. The primary side pressure is the gas pressure upstream of the second opening. The secondary side pressure is the gas pressure downstream of the second opening. As a result, the valve body moves in the direction of seating on the valve seat due to the biasing force of the biasing member, and eventually the tip of the valve body seats on the valve seat. The tip of the valve body is maintained in a state pressed against the valve seat by the biasing force of the biasing member. Therefore, the airtightness of the gas tank is ensured.

[0014] In the above-described check valve, the gas may be high-pressure hydrogen gas, and the hydrogen gas, after passing through the second opening, may be supplied to the gas tank of the fuel cell vehicle.

[0015] This configuration improves the responsiveness of the pressure reducing valve's opening operation, thereby shortening the time required to fill the gas tank with hydrogen gas. [Effects of the Invention]

[0016] According to the check valve of the present invention, the responsiveness of the valve opening operation can be improved. [Brief explanation of the drawing]

[0017] [Figure 1] This is a cross-sectional view of a valve assembly in which one embodiment of a check valve is used. [Figure 2] Figure 1 is a cross-sectional view of the valve assembly near the check valve in the closed state. [Figure 3] Figure 1 is an enlarged cross-sectional view of the valve assembly near the check valve in a slightly open state. [Figure 4] Figure 1 is an enlarged cross-sectional view of the valve assembly near the check valve in the open state. [Modes for carrying out the invention]

[0018] The following describes an embodiment of a check valve. The check valve is incorporated into, for example, a valve assembly. <Valve assembly> As shown in FIG. 1, the valve assembly 1 is attached to, for example, the gas tank 2 of a fuel cell vehicle. The valve assembly 1 is also connected to an external device 3 via a pipe (not shown). The external device 3 includes a fuel cell mounted on the vehicle and a hydrogen gas supply source such as a hydrogen station. The gas tank 2 stores high-pressure hydrogen gas at about 72.5 MPa, for example. The valve assembly 1 controls the flow of hydrogen gas filled in the gas tank 2 and the hydrogen gas sent out from the gas tank 2.

[0019] The valve assembly 1 has a body 11 and a plurality of valve sub-assemblies assembled to the body 11. The plurality of valve sub-assemblies includes, for example, a manual valve 12, a composite valve 13, a safety valve 14, and a check valve 15. The valve assembly 1 may have a joint 16 for connecting the previous pipe.

[0020] The body 11 is made of metal. The body 11 has, for example, a main body 11A and a protruding portion 11B protruding laterally from the main body 11A. The body 11 also has a plurality of mounting holes. The plurality of mounting holes includes a joint mounting hole 21 for mounting the joint 16, a manual valve mounting hole 22 for mounting the manual valve 12, an integrated mounting hole 23 for mounting the safety valve 14 and the check valve 15, and a composite valve mounting hole 24 for mounting the composite valve 13.

[0021] The joint mounting hole 21 opens on the side surface of the main body 11A opposite to the protruding portion 11B. The manual valve mounting hole 22 opens on the first end surface of the main body 11A. The integrated mounting hole 23 opens on the tip surface of the protruding portion 11B. The composite valve mounting hole 24 opens on the second end surface of the main body 11A. The second end surface is the surface of the main body 11A on the opposite side of the first end surface in the axial direction of the main body 11A. The joint mounting hole 21, the manual valve mounting hole 22, the integrated mounting hole 23, and the composite valve mounting hole 24 are, for example, round holes. A round hole is a hole having a circular cross-sectional shape in a direction perpendicular to the axial direction of the hole.

[0022] The integrated mounting hole 23 has a mounting hole 23A for a safety valve to which the safety valve 14 is attached and a mounting hole 23B for a check valve to which the check valve 15 is attached. The mounting hole 23A for the safety valve and the mounting hole 23B for the check valve are arranged in the protruding direction of the protruding portion 11B. The mounting hole 23A for the safety valve and the mounting hole 23B for the check valve communicate with each other. The mounting hole 23A for the safety valve is located on the tip side of the protruding portion 11B, and the mounting hole 23B for the check valve is located on the base end side of the protruding portion 11B. The mounting hole 23A for the safety valve opens to the tip surface of the protruding portion 11B.

[0023] The body 11 has a gas flow path 30 through which hydrogen gas flows. The gas flow path 30 includes a first flow path 31 connected to the gas tank 2 and a second flow path 32 connected to the external device 3 via the joint 16.

[0024] The first flow path 31 has a filling path 31A and a delivery path 31B. The filling path 31A communicates the integrated mounting hole 23 with the gas tank 2. The filling path 31A opens to the inner peripheral surface of the mounting hole 23B for the check valve of the integrated mounting hole 23. The delivery path 31B communicates the mounting hole 24 for the combined valve with the gas tank 2. The delivery path 31B opens to the inner peripheral surface of the mounting hole 24 for the combined valve.

[0025] The second flow path 32 has a first portion 32A, a second portion 32B, and a third portion 32C. The first portion 32A is a portion that communicates the mounting hole 22 for the manual valve and the mounting hole 24 for the combined valve. The first portion 32A extends in the axial direction of the main body 11A. The second portion 32B is a portion that communicates the mounting hole 21 for the joint and the first portion 32A. The second portion 32B extends in a direction orthogonal to the axial direction of the main body 11A. The third portion 32C is a portion that communicates the integrated mounting hole 23 and the first portion 32A. The third portion 32C extends in a direction orthogonal to the axial direction of the main body 11A.

[0026] The fitting 16 is cylindrical. The fitting 16 is attached to the fitting mounting hole 21, for example, by screwing it into the fitting mounting hole 21. The fitting 16 has a fitting passage 16A. The fitting passage 16A communicates with the second portion 32B of the second flow path 32. The fitting 16 is the portion to which piping (not shown) extending from the external device 3 is connected. The second flow path 32 is connected to the external device 3 via the piping.

[0027] The manual valve 12 is mounted in the manual valve mounting hole 22. The manual valve 12 controls the flow of hydrogen gas between the second portion 32B of the second flow path 32 and the first portion 32A of the second flow path 32. The manual valve 12 can be switched between a closed state and an open state by manual operation. The closed state is a state in which the flow of hydrogen gas between the second portion 32B and the first portion 32A is blocked. The open state is a state in which the flow of hydrogen gas between the second portion 32B and the first portion 32A is permitted.

[0028] The safety valve 14 is installed in the safety valve mounting hole 23A. The safety valve 14 is intended to prevent the hydrogen gas pressure in the gas tank 2 from reaching excessive pressure. The safety valve 14 switches between a closed state and an open state depending on the temperature of the safety valve 14. When the temperature of the safety valve 14 is below the threshold temperature, the safety valve 14 is maintained in the closed state. The closed state is a state in which hydrogen gas flowing into the inlet of the safety valve 14 is not released to the outside. When the temperature of the safety valve 14 exceeds the threshold temperature, a soluble metal stopper provided inside the safety valve 14 dissolves, allowing the safety valve 14 to irreversibly transition from the closed state to the open state. The open state is a state in which hydrogen gas flowing into the inlet of the safety valve 14 is released to the outside. The threshold temperature is set, for example, based on the temperature of the safety valve 14 when the hydrogen gas pressure in the gas tank 2 reaches a pressure considered to be excessive.

[0029] The check valve 15 is installed in the check valve mounting hole 23B. The check valve 15 is for preventing backflow of hydrogen gas filled in the gas tank 2. The check valve 15 restricts the flow of hydrogen gas from the filling passage 31A of the first flow path 31 to the third section 32C of the second flow path 32, while allowing the flow of hydrogen gas from the third section 32C to the filling passage 31A. The check valve 15 controls the flow of hydrogen gas in a different manner than the safety valve 14.

[0030] The composite valve 13 is mounted in the mounting hole 24 for the composite valve. The composite valve 13 has the function of both a solenoid valve and a check valve. The combined valve 13 controls the flow of hydrogen gas between the outlet passage 31B of the first flow path 31 and the first portion 32A of the second flow path 32 through the function of a solenoid valve. The solenoid valve function part of the combined valve 13 opens when energized. That is, the flow of hydrogen gas between the outlet passage 31B of the first flow path 31 and the first portion 32A of the second flow path 32 is permitted. The solenoid valve function part of the combined valve 13 closes when the energization is cut off. That is, the flow of hydrogen gas between the outlet passage 31B of the first flow path 31 and the first portion 32A of the second flow path 32 is cut off. The solenoid valve function part is the part of the combined valve 13 that functions as a solenoid valve.

[0031] The combined valve 13, through its check valve function, allows the flow of hydrogen gas from the discharge passage 31B of the first flow path 31 to the first portion 32A of the second flow path 32, while restricting the flow of hydrogen gas from the first portion 32A of the second flow path 32 to the discharge passage 31B of the first flow path 31.

[0032] <Check valve 15> Next, the configuration of the check valve 15 will be described in detail. As shown in Figure 2, the check valve 15 has a housing 41. The housing 41 is cylindrical with a first end closed. The housing 41 has a cylindrical portion 41A and an end wall portion 41B provided at the first end of the cylindrical portion 41A. The inside of the cylindrical portion 41A is configured as a housing hole 41C that opens at the second end of the cylindrical portion 41A. The second end is the end of the cylindrical portion 41A opposite to the first end in the axial direction of the cylindrical portion 41A. The second end is located upstream of the first end.

[0033] An enlarged diameter hole portion 41D is provided at the second end of the housing hole 41C. The inner diameter of the enlarged diameter hole portion 41D is set to be larger than the inner diameter of the portion of the housing hole 41C on the first end side. The outer diameter of the cylindrical portion 41A is set to be smaller than the inner diameter of the check valve mounting hole 23B, except at the second end. The outer diameter of the second end of the cylindrical portion 41A is set to be approximately the same as, or slightly smaller than, the inner diameter of the check valve mounting hole 23B.

[0034] The cylindrical portion 41A has one or more lateral holes 41E. For example, the cylindrical portion 41A has six lateral holes 41E that are equally spaced in the circumferential direction. The lateral holes 41E are located in the axial direction of the cylindrical portion 41A, closer to the second end than to the first end. The lateral holes 41E are elongated holes that extend in the axial direction of the cylindrical portion 41A. The lateral holes 41E penetrate the circumferential wall of the cylindrical portion 41A in the thickness direction.

[0035] The end wall portion 41B has a threaded portion 41F. A male thread is provided on the outer circumferential surface of the threaded portion 41F. The threaded portion 41F is provided at the first end of the end wall portion 41B. The first end is the end of the end wall portion 41B opposite to the cylindrical portion 41A in the axial direction of the housing 41. The outer diameter of the end wall portion 41B is set to be smaller than the inner diameter of the check valve mounting hole 23B, except for the threaded portion 41F. The outer diameter of the portion of the end wall portion 41B other than the threaded portion 41F may be the same as the outer diameter of the cylindrical portion 41A.

[0036] The housing 41 is installed inside the check valve mounting hole 23B by inserting the cylindrical portion 41A into the check valve mounting hole 23B and screwing the threaded portion 41F into the check valve mounting hole 23B. The housing 41 is maintained in a state where axial movement is restricted. By installing the housing 41 in the check valve mounting hole 23B, a cylindrical space S1 is formed between the inner circumferential surface of the check valve mounting hole 23B and the outer circumferential surface of the housing 41. The space S1 is in communication with the filling passage 31A of the first flow path 31.

[0037] The end wall portion 41B has a connecting passage 41G. The connecting passage 41G is a passage for connecting the filling passage 31A of the first flow path 31 to the safety valve 14 in the mounting hole 23A for the safety valve via the space S1.

[0038] The connecting passage 41G has a longitudinal passage 41H extending in the axial direction and one or more transverse passages 41I extending in a direction perpendicular to the axial direction. The connecting passage 41G has, for example, four transverse passages 41I located at equal intervals in the circumferential direction. The first end of a transverse passage 41I opens to the outer circumferential surface of the end wall portion 41B. The second end of a transverse passage 41I opens to a position close to the first end of a longitudinal passage 41H. The second end of a longitudinal passage 41H opens to a mounting hole 23A for a safety valve. The second end is the end of the longitudinal passage 41H opposite to the first end.

[0039] The end wall portion 41B has a back pressure hole 41J. The back pressure hole 41J is a through hole that connects the housing hole 41C to the communication passage 41G. The back pressure hole 41J extends in the axial direction of the housing 41. The end wall portion 41B also has one or more tool holes 41K for fitting with a tool (not shown). The tool holes 41K open, for example, in the axial direction on the side opposite to the cylindrical portion 41A. If the end wall portion 41B has multiple tool holes 41K, the tool holes 41K are provided, for example, at equal angular intervals around the longitudinal passage 41H.

[0040] The check valve 15 has a valve seat 42. The valve seat 42 is, for example, a cylinder made of synthetic resin. The valve seat 42 is mounted inside the enlarged hole 41D of the housing 41. When the housing 41 is fixed inside the check valve mounting hole 23B, the valve seat 42 is axially sandwiched between the inner end face of the check valve mounting hole 23B and the housing 41. This seals the space between the inner end face of the check valve mounting hole 23B and the housing 41. The valve seat 42 has a valve port 42A that penetrates axially. The inner circumferential surface of the valve port 42A has a tapered surface 42B. The inner diameter of the tapered surface 42B gradually increases toward the inner end face of the enlarged hole 41D.

[0041] The check valve 15 has a valve body 43. The valve body 43 is made of metal, for example. The valve body 43 is cylindrical, for example, and is housed inside the housing hole 41C of the housing 41. The valve body 43 is movable in the axial direction. The valve body 43 is configured to open and close the valve port 42A of the valve seat 42. The valve body 43 has a tip and a base. The tip is the end of the valve body 43 that is located on the valve seat 42 side in the axial direction. The base is the end of the valve body 43 that is located on the opposite side of the valve seat 42 in the axial direction. The tip of the valve body 43 has a tapered surface 43A. The outer diameter of the tip of the valve body 43 gradually decreases towards the tip. The outer diameter of the cylindrical portion of the valve body 43, excluding the tapered surface 43A, is about the same as the inner diameter of the housing hole 41C. The outer circumferential surface of the cylindrical portion of the valve body 43, excluding the tapered surface 43A, slides axially against the inner circumferential surface of the housing hole 41C.

[0042] The check valve 15 has a biasing member 44. The biasing member 44 is, for example, a compression coil spring. The biasing member 44 is housed inside the housing hole 41C of the housing 41. The biasing member 44 is interposed between the valve body 43 and the end wall portion 41B of the housing 41. The biasing member 44 generates a biasing force that biases the valve body 43 in the closing direction. The closing direction is the upstream direction of the hydrogen gas flow and away from the end wall portion 41B.

[0043] The check valve 15 switches between a closed state and an open state. The closed state is when the tip of the valve body 43 is seated on the valve seat 42 and the valve port 42A is closed. When the check valve 15 is in the closed state, the flow of hydrogen gas between the filling passage 31A of the first flow path 31 and the third portion 32C of the second flow path 32 is blocked. The open state is when the tip of the valve body 43 is away from the valve seat 42, that is, the valve port 42A is open. When the check valve 15 is in the open state, the flow of hydrogen gas between the filling passage 31A of the first flow path 31 and the third portion 32C of the second flow path 32 is permitted.

[0044] <Operation of valve assembly 1 during hydrogen gas filling> Next, the operation of the valve assembly 1 when filling the gas tank 2 with hydrogen gas will be described. In this case, the piping extending from the hydrogen gas supply source, which is an external device 3, is connected to the fitting 16. In the initial state before hydrogen gas is supplied through the fitting 16, the valve body 43 is maintained in a closed state with its tip pressed against the valve seat 42 by the biasing force of the biasing member 44.

[0045] When hydrogen gas is supplied from the hydrogen gas source via the fitting 16, the hydrogen gas flows into the check valve 15 through the second portion 32B, the first portion 32A, and the third portion 32C of the second flow path 32. The tip surface of the valve body 43 is subjected to the pressure of the hydrogen gas, causing the valve body 43 to move in the opening direction against the biasing force of the biasing member 44. The opening direction is downstream of the hydrogen gas flow and away from the valve seat 42. As the tip of the valve body 43 separates from the valve seat 42, the check valve 15 opens. As a result, the third portion 32C of the second flow path 32 communicates with the filling passage 31A of the first flow path 31 via the lateral hole 41E and space S1 of the housing 41. This allows the hydrogen gas to flow into the gas tank 2 via the filling passage 31A.

[0046] At this time, hydrogen gas from the supply source flows into the inlet of the safety valve 14 through space S1 and communication passage 41G. However, if the temperature of the safety valve 14 does not reach a high temperature exceeding the threshold temperature, the safety valve 14 is kept closed. Therefore, if the temperature of the safety valve 14 does not reach a high temperature exceeding the threshold temperature, hydrogen gas will not be released to the outside through the safety valve 14.

[0047] Furthermore, hydrogen gas from the supply source also flows into the composite valve 13 through the second section 32B and the first section 32A of the second flow path 32. However, the composite valve 13, through its check valve function, restricts the flow of hydrogen gas from the first section 32A of the second flow path 32 to the discharge passage 31B of the first flow path 31. In other words, the composite valve 13 is kept closed. Therefore, hydrogen gas does not flow into the gas tank 2 through the discharge passage 31B of the first flow path 31.

[0048] Once the hydrogen gas filling of the gas tank 2 is complete, the valve on the hydrogen gas supply source side is closed, stopping the supply of hydrogen gas from the hydrogen gas supply source to the gas tank 2. At this time, the pressure on the primary side of the check valve 15 and the pressure on the secondary side of the check valve 15 are in equilibrium. The primary side pressure is the pressure of the hydrogen gas acting on the tip of the valve body 43, i.e., the gas pressure on the upstream side relative to the second opening δ2. The secondary side pressure is the hydrogen gas pressure on the downstream side relative to the second opening δ2. As a result, the valve body 43 moves in the closing direction due to the biasing force of the biasing member 44, and eventually the tip of the valve body 43 seats on the valve seat 42. As a result, the valve opening 42A of the valve seat 42 is sealed again by the tip of the valve body 43. The tip of the valve body 43 is maintained pressed against the valve seat 42 by the biasing force of the biasing member 44. Therefore, the airtightness of the gas tank 2 is ensured.

[0049] <Operation of valve assembly 1 when hydrogen gas is delivered> Next, the operation of valve assembly 1 when hydrogen gas is delivered from gas tank 2 will be explained. In this case, the piping extending from the fuel cell, which is an external device 3, is connected to fitting 16.

[0050] Hydrogen gas in the gas tank 2 flows into the combined valve 13 via the discharge passage 31B of the first flow path 31. When hydrogen gas is discharged, the solenoid valve function section of the combined valve 13 opens when energized. This allows the flow of hydrogen gas between the discharge passage 31B of the first flow path 31 and the first section 32A of the second flow path 32. The hydrogen gas is supplied to the fuel cell, which is an external device 3, via the first section 32A and the second section 32B of the second flow path 32, and the joint passage 16A.

[0051] At this time, hydrogen gas in the gas tank 2 also flows into the check valve 15 through the filling passage 31A of the first flow path 31. The hydrogen gas flows into the interior of the containment hole 41C through the space S1, the communication passage 41G, and the back pressure hole 41J. Due to the biasing force of the biasing member 44, and the pressure of the hydrogen gas on the base end of the valve body 43, the tip of the valve body 43 is pressed against the valve seat 42. That is, the check valve 15 is maintained in a closed state. As a result, hydrogen gas is prevented from flowing back into the gas tank 2 through the first portion 32A, the third portion 32C, and the check valve 15 of the second flow path 32.

[0052] Furthermore, hydrogen gas in the gas tank 2 flows into the inlet of the safety valve 14 through the filling passage 31A, space S1, and communication passage 41G of the first flow path 31. However, the safety valve 14 remains closed unless its temperature exceeds the threshold temperature. Therefore, if the temperature of the safety valve 14 does not exceed the threshold temperature, hydrogen gas will not be released to the outside.

[0053] <When safety valve 14 is at high temperature> Next, we will describe the operation of the valve assembly 1 when the temperature of the safety valve 14 reaches a high temperature that exceeds the threshold temperature.

[0054] If the temperature of the gas tank 2 rises for any reason and the temperature of the safety valve 14 reaches a high temperature exceeding the threshold temperature, the safety valve 14 can transition from a closed state to an open state. Hydrogen gas in the gas tank 2 flows into the inlet of the safety valve 14 through the filling passage 31A, space S1, and communication passage 41G of the first flow path 31. The pressure of this incoming hydrogen gas opens the safety valve 14. As the hydrogen gas flowing into the safety valve 14 is released to the outside through the open safety valve 14, the pressure in the gas tank 2 is prevented from reaching excessive pressure as the temperature of the gas tank 2 rises.

[0055] <Supplementary explanation of check valve 15> Next, I will provide a supplementary explanation regarding the configuration of the check valve 15. The time required to fill the gas tank 2 with hydrogen gas is affected by the responsiveness of the opening operation of the check valve 15. To shorten the filling time, it is necessary to improve the responsiveness of the opening operation of the check valve 15. For this reason, the following configuration is adopted in this embodiment.

[0056] As shown in Figure 2, the shape of the valve body 43, the position of the lateral hole 41E relative to the valve body 43, and the size of the lateral hole 41E are set such that when the check valve 15 is in the closed state, the opening area of ​​the lateral hole 41E in the housing 41 is "0". The opening area is the area of ​​the portion of the lateral hole 41E that is exposed to the housing hole 41C of the housing 41. When the check valve 15 is in the closed state, the lateral hole 41E in the housing 41 is blocked by the outer circumferential surface of the valve body 43.

[0057] As shown in Figure 3, the position and size of the lateral hole 41E relative to the valve body 43 are set such that the opening area of ​​the lateral hole 41E in the housing 41 is "0" even when the check valve 15 is in a slightly open state. The slightly open state is a state in which the tip of the valve body 43 is separated from the valve seat 42 by a small distance. A first opening δ1, which is a small gap, is formed between the valve seat 42 and the tip of the valve body 43. The first opening δ1 is, for example, an annular gap between the tapered surface 42B of the valve seat 42 and the tapered surface 43A of the valve body 43. The first opening δ1 functions as an inlet for hydrogen gas.

[0058] Furthermore, when the check valve 15 is in a slightly open state, the lateral hole 41E of the housing 41 is kept closed from the inside by the outer circumferential surface of the cylindrical portion of the valve body 43. As shown in Figure 4, when the check valve 15 is in the open state, the tip of the valve body 43 is separated from the valve seat 42. The separation distance is longer than the separation distance when the check valve is in the slightly open state. In the open state, the base end of the valve body 43 is in axial contact with the end wall portion 41B of the housing 41. The opening area of ​​the first opening δ1 when the check valve 15 is in the open state is larger than the opening area of ​​the first opening δ1 when the check valve 15 is in the slightly open state. Also, when the check valve 15 is in the open state, a part of the lateral hole 41E of the housing 41 opens into the housing hole 41C, forming a second opening δ2. The opening area of ​​the second opening δ2 is maximized when the check valve 15 is in the open state. There are as many second openings δ2 as there are lateral holes 41E. The second openings δ2 function as outlets for hydrogen gas.

[0059] Regardless of the position of the valve body 43, the first opening area A1, which is the opening area of ​​the first opening δ1, and the second opening area A2, which is the opening area of ​​the second opening δ2, are set to satisfy the following equation (1).

[0060] A1>N·A2 …(1) However, "N" is the number of horizontal openings 41E. "·" indicates multiplication. "N·A2" is the sum of the second opening areas A2.

[0061] As shown in equation (2) below, the valve opening area A0, which is the opening area of ​​the valve port 42A of the valve seat 42, is set to be wider than the sum of the second opening areas A2, "N·A2", regardless of the position of the valve body 43.

[0062] A0>N·A2 …(2) As shown in equation (3) below, the valve opening area A0 is set, for example, to be wider than the sum of the second opening areas A2 "N·A2" when the check valve 15 is in the open state.

[0063] A0 > A1 …(3) Equations (1) to (3) above also hold true when the check valve 15 is maintained in the closed state shown in Figure 2. Furthermore, equations (1) to (3) above also hold true during the period when the check valve 15 transitions from the slightly open state shown in Figure 3 to the open state shown in Figure 4.

[0064] The position of the lateral hole 41E relative to the valve body 43, and the size of the lateral hole 41E, are set such that the extended surface L1, which is an extension of the tapered surface 43A of the valve body 43, does not intersect with the inner circumferential surface of the lateral hole 41E during the period from when the second opening δ2 begins to form until the second opening area A2 is at its maximum. The inner circumferential surface of the lateral hole 41E is a part of the inner circumferential surface of the end of the lateral hole 41E on the side closer to the end wall portion 41B. When the check valve 15 is in the open state, the second opening area A2 is at its maximum. At this time, the extended surface L1 contacts the corner formed by the inner circumferential surface of the lateral hole 41E and the outer circumferential surface of the housing 41 at the end of the lateral hole 41E on the side closer to the end wall portion 41B.

[0065] <Function of check valve 15> The check valve 15 configured in this way performs the following functions. As shown in Figure 3, when hydrogen gas is filled into the gas tank 2, the pressure of the hydrogen gas flowing into the check valve 15 causes the valve body 43 to begin moving in the opening direction against the biasing force of the biasing member 44. As a result, the tip of the valve body 43 separates from the valve seat 42, causing the first opening δ1 to begin to form and the seal of the valve port 42A to be released. However, in the slightly open state, which is the stage when the valve body 43 has just begun to move, the lateral hole 41E remains closed by the outer circumferential surface of the valve body 43. Therefore, although hydrogen gas flows into the introduction space S2 through the first opening δ1, it does not flow into the lateral hole 41E. The introduction space S2 is the space enclosed by the inner circumferential surface of the housing 41, the valve seat 42, and the tapered surface 43A of the valve body 43.

[0066] When hydrogen gas flows into the introduction space S2 with the lateral hole 41E closed by the outer circumferential surface of the valve body 43, the pressure-receiving diameter of the valve body 43 increases from the first pressure-receiving diameter φ1 to the second pressure-receiving diameter φ2. The pressure-receiving diameter is the diameter of the region of the valve body 43 that receives the pressure of the hydrogen gas. The first pressure-receiving diameter φ1 is the pressure-receiving diameter of the valve body 43 when the check valve 15 is in the closed state, and is the same as the diameter of the tip surface of the valve body 43. The second pressure-receiving diameter φ2 is the pressure-receiving diameter of the valve body 43 when the check valve 15 is in the slightly open state, and is the same as the maximum outer diameter of the valve body 43. The maximum outer diameter is the outer diameter of the cylindrical portion of the valve body 43 excluding the tapered surface 43A.

[0067] An increase in the pressure-receiving diameter also means an increase in the pressure-receiving area. The pressure-receiving area is the area of ​​the valve body 43 that receives the pressure of the hydrogen gas. In other words, the load acting on the valve body 43 in the valve-opening direction is determined by the pressure-receiving diameter. When the check valve 15 transitions from a closed state to a slightly open state, the pressure-receiving diameter of the valve body 43 increases from the first pressure-receiving diameter φ1 to the second pressure-receiving diameter φ2, thereby increasing the load acting on the valve body 43 in the valve-opening direction. Therefore, the valve body 43 moves smoothly in the valve-opening direction due to the pressure of the hydrogen gas.

[0068] At the stage when the first opening δ1 begins to form, the opening area A1 of the first opening δ1 is narrower than the opening area A0 of the valve port 42A. Therefore, when hydrogen gas that has passed through the valve port 42A flows into the first opening δ1, the first opening δ1 functions as a throttling, causing a pressure loss in the hydrogen gas. As a result, the pressure of the hydrogen gas decreases. As shown in equation (4), the pressure P1 of the hydrogen gas after passing through the first opening δ1 is lower than the pressure P0 of the hydrogen gas before passing through the first opening δ1.

[0069] P0 > P1 …(4) Due to the pressure loss that occurs when hydrogen gas passes through the first opening δ1, the difference between the pressure P0 of the hydrogen gas before passing through the first opening δ1 and the pressure P1 of the hydrogen gas after passing through the first opening δ1 tends to become large. As a result, the hydrogen gas that has passed through the valve port 42A flows smoothly into the introduction space S2 through the first opening δ1.

[0070] As shown in Figure 4, the pressure of the hydrogen gas causes the valve body 43 to move further in the opening direction. After the tapered surface 43A of the valve body 43 reaches the lateral hole 41E, the tapered surface 43A overlaps radially with respect to the lateral hole 41E, forming a second opening δ2. This releases the blockage of the lateral hole 41E, and the introduction space S2 and the inside of the lateral hole 41E communicate through the second opening δ2. As a result, hydrogen gas is supplied to the gas tank 2 through the lateral hole 41E, the space S1, and the filling passage 31A.

[0071] At the stage when the second opening δ2 begins to form, the sum of the opening areas A2 of the second opening δ2 is smaller than the opening area A1 of the first opening δ1. Therefore, when hydrogen gas flows into the second opening δ2 via the first opening δ1, the second opening δ2 functions as a throttling, causing a pressure loss in the hydrogen gas. As a result, the pressure of the hydrogen gas decreases. As shown in equation (5), the pressure P2 of the hydrogen gas after passing through the second opening δ2 is lower than the pressure P1 of the hydrogen gas before passing through the second opening δ2.

[0072] P1 > P2 …(5) The pressure loss that occurs when hydrogen gas passes through the second opening δ2 tends to increase the difference between the pressure P1 of the hydrogen gas before passing through the second opening δ2 and the pressure P2 of the hydrogen gas after passing through the second opening δ2. As a result, the hydrogen gas flowing into the introduction space S2 flows smoothly into the lateral hole 41E through the second opening δ2.

[0073] As the valve body 43 moves in the opening direction, the second opening area A2, which is the opening area of ​​the second opening δ2, gradually increases. As the second opening area A2 increases, the flow rate of hydrogen gas flowing from the introduction space S2 into the lateral hole 41E increases.

[0074] The movement of the valve body 43 in the opening direction is restricted by the base end of the valve body 43 contacting the end wall portion 41B of the housing 41 in the axial direction. At this time, the second opening area A2 is maximized. The state in which the second opening area A2 is maximized is the fully open state of the check valve 15. Even when the check valve 15 is fully open, the sum of the second opening areas A2 is smaller than the first opening area A1, which is the opening area of ​​the first opening δ1.

[0075] Therefore, a pressure loss occurs when the hydrogen gas passes through the second opening δ2. This pressure loss tends to increase the difference between the pressure P1 of the hydrogen gas before passing through the second opening δ2 and the pressure P2 of the hydrogen gas after passing through the second opening δ2. As a result, the hydrogen gas flowing into the introduction space S2 flows smoothly into the lateral hole 41E through the second opening δ2.

[0076] Furthermore, the base end of the valve body 43 is maintained in axial contact with the end wall portion 41B of the housing 41 by the pressure of the hydrogen gas. In other words, the check valve 15 is maintained in a fully open state where the second opening area A2 is maximized. This ensures a sufficient flow rate of hydrogen gas into the lateral hole 41E through the second opening δ2.

[0077] Furthermore, the hydrogen gas supplied from the first opening δ1 flows into the transverse hole 41E through the second opening δ2 while being guided by the tapered surface 43A of the valve body 43. At this time, the hydrogen gas flows into the transverse hole 41E in a direction along the extension surface L1. Here, during the period from when the second opening δ2 begins to form until the second opening area A2 is at its maximum, the size of the transverse hole 41E is set such that the extension surface L1, which is a virtual extension of the tapered surface 43A of the valve body 43, does not intersect with the inner circumferential surface of the transverse hole 41E. The inner circumferential surface of the transverse hole 41E is a part of the inner circumferential surface of the end of the transverse hole 41E on the side closer to the end wall portion 41B. Therefore, the hydrogen gas flowing into the transverse hole 41E along the extension surface L1 is prevented from hitting the inner circumferential surface of the transverse hole 41E. In other words, since there is nothing to obstruct the flow of hydrogen gas flowing into the transverse hole 41E, the hydrogen gas flowing into the transverse hole 41E flows out smoothly into space S1.

[0078] As described above, in the check valve 15, the upstream hydrogen gas pressures P0 and P1 relative to the second opening δ2 are higher than the downstream hydrogen gas pressure P2 relative to the second opening δ2. By intentionally creating this pressure difference, the responsiveness of the check valve 15's opening operation is improved. For example, when filling the gas tank 2 with hydrogen gas, the time required from when the hydrogen gas flows into the check valve 15 until it flows out of the check valve 15, i.e., the time lag, can be shortened. Therefore, the time required to fill the gas tank 2 with hydrogen gas can be shortened.

[0079] <Comparative Example> Incidentally, if the first opening area A1 and the second opening area A2 are set such that the opening area A2 of the second opening δ2 is larger than the opening area A1 of the first opening δ1, the following concerns arise.

[0080] In other words, when hydrogen gas flows into the second opening δ2 via the first opening δ1, the second opening δ2 does not function as a throttling, so no pressure loss occurs in the hydrogen gas. Therefore, the pressure P2 of the hydrogen gas after passing through the second opening δ2 is approximately the same as the pressure P1 of the hydrogen gas before passing through the second opening δ2. That is, it is difficult for a difference to occur between the pressure P1 of the hydrogen gas before passing through the second opening δ2 and the pressure P2 of the hydrogen gas after passing through the second opening δ2. Consequently, there is a risk that the responsiveness required for the opening operation of the check valve 15 cannot be ensured.

[0081] <Effects of the Embodiment> This embodiment provides the following effects. (1) Regardless of the position of the valve body 43, the parts of the check valve 15 are configured such that the opening area A2 of the second opening δ2 is narrower than the opening area A1 of the first opening δ1. Because the opening area of ​​the second opening δ2, which is the outlet for hydrogen gas, is narrower than the opening area of ​​the first opening δ1, which is the inlet for hydrogen gas, the second opening δ2 functions as a throttling when hydrogen gas passes through it. As a result, a pressure loss occurs in the hydrogen gas when it passes through the second opening δ2. Therefore, the pressure P1 of the hydrogen gas upstream of the second opening δ2 is higher than the pressure P2 of the hydrogen gas downstream of the second opening δ2. Consequently, the hydrogen gas supplied from the first opening δ1 flows smoothly into the lateral hole 41E through the second opening δ2, improving the responsiveness of the opening operation of the check valve 15. Furthermore, by improving the responsiveness of the opening operation of the check valve 15, the time required to fill the gas tank 2 with hydrogen gas can be shortened.

[0082] (2) When the valve body 43 moves away from the valve seat 42, the first opening δ1 opens before the second opening δ2. As a result, when the first opening δ1 begins to open, the second opening δ2 is closed, and hydrogen gas flows from the first opening δ1 into the interior of the housing 41, i.e., the introduction space S2, thereby increasing the pressure-receiving area of ​​the valve body 43. As a result, the load acting on the valve body 43 in the direction away from the valve seat 42 increases. Therefore, the valve body 43 can be smoothly moved away from the valve seat 42 by the pressure of the hydrogen gas. The second opening δ2 can be properly opened as the valve body 43 moves smoothly to a position where the tapered surface 43A radially overlaps with the lateral hole 41E.

[0083] (3) During the period from when the second opening δ2 begins to form until the second opening area A2 reaches its maximum, the size of the lateral hole 41E is set such that the extension surface L1, which is a virtual extension of the tapered surface 43A of the valve body 43, does not intersect with the inner surface of the lateral hole 41E. The inner surface of the lateral hole 41E is a part of the inner surface of the end of the lateral hole 41E that is close to the end wall portion 41B. Therefore, the hydrogen gas flowing into the lateral hole 41E along the extension surface L1 is prevented from hitting the inner surface of the lateral hole 41E. In other words, since there is nothing to obstruct the flow of hydrogen gas flowing into the lateral hole 41E, the hydrogen gas flowing into the lateral hole 41E can be smoothly discharged from the space S1. Therefore, the hydrogen gas can be quickly filled into the gas tank 2.

[0084] (4) After passing through the second opening δ2, the hydrogen gas is supplied to the gas tank 2. The pressure of the hydrogen gas after passing through the second opening δ2 acts on the base end of the valve body 43, which is the end opposite to the tip. Therefore, when the gas tank 2 is filled and the supply of gas from the gas source to the gas tank 2 is stopped, the pressure on the primary side of the check valve 15 and the pressure on the secondary side of the check valve 15 become balanced. As a result, the valve body 43 moves in the direction of seating on the valve seat 42 due to the biasing force of the biasing member 44, and eventually the tip of the valve body 43 seats on the valve seat 42. The tip of the valve body 43 is maintained in a state pressed against the valve seat 42 by the biasing force of the biasing member 44. Thus, the airtightness of the gas tank 2 is ensured.

[0085] (5) The integrated mounting hole 23 of the body 11 is a single hole and has a mounting hole 23A for a safety valve and a mounting hole 23B for a check valve. The mounting hole 23A for the safety valve and the mounting hole 23B for the check valve are located coaxially. Therefore, the structure of the body 11 can be simplified compared to when the mounting hole 23A for the safety valve and the mounting hole 23B for the check valve are separate holes. In addition, the processing time for the body 11 can be reduced.

[0086] (6) The check valve 15 is a partial assembly. A partial assembly is assembled so that the parts constituting a specific functional part can be handled as a single unit. In other words, the check valve 15 can be handled individually. For this reason, when attaching the check valve 15 to the body 11, the check valve 15 can be easily attached to the check valve mounting hole 23B via the safety valve mounting hole 23A. Also, when replacing the check valve 15, the check valve 15 can be easily removed from the check valve mounting hole 23B via the safety valve mounting hole 23A. Incidentally, the safety valve 14 is also a partial assembly and can be handled individually.

[0087] (7) A space S is formed between the outer circumferential surface of the housing 41 of the check valve 15 and the inner circumferential surface of the mounting hole 23B for the check valve, which functions as a passage for hydrogen gas. Hydrogen gas flowing into the check valve 15 flows out into space S through the lateral hole 41E of the housing 41. The hydrogen gas flowing into space S is supplied to the gas tank 2 via the filling passage 31A and also flows into the inlet of the safety valve 14 via the connecting passage 41G. In other words, the hydrogen gas flowing into space S flows axially along the outer circumferential surface of the housing 41. As a result, the generation of noise and vibration associated with the flow of hydrogen gas is suppressed.

[0088] <Other Embodiments> This embodiment may be implemented with the following modifications. The opening area of ​​the second opening δ2 may be adjusted by providing, for example, a mesh-like member in the lateral hole 41E of the housing 41. The opening area of ​​the second opening δ2 decreases by the amount that the mesh-like member is exposed to the housing hole 41C of the housing 41. Also, the pressure loss of hydrogen gas increases by the amount that the mesh-like member is exposed to the housing hole 41C of the housing 41.

[0089] Depending on the product specifications, the parts of the check valve 15 may be configured such that when the valve body 43 moves in the opening direction, which is away from the valve seat 42, the first opening δ1 and the second opening δ2 open at the same time.

[0090] The valve assembly 1 may be configured to control the flow of gases other than high-pressure hydrogen gas, not just high-pressure hydrogen gas. The check valve 15 may be constructed as an independent valve device rather than as one of several valve subassemblies constituting the valve assembly 1. In this case, the check valve 15 may be configured as a closed space S. The check valve 15 may also be configured to have a body 11. However, the shape and size of the body 11 are adjusted as appropriate. The housing 41 is configured to close the opening of the longitudinal passage 41H. [Explanation of Symbols]

[0091] 2... Gas tank 15… Check valve 31...First flow path (gas flow path) 32...Second flow path (gas flow path) 41… Housing 41E…Horizontal hole 42... Valve seat 43... Valve body 43A... Tapered surface 44… Biasing member L1…extension surface δ1...First opening δ2...Second opening

Claims

1. A check valve installed in a gas flow path, A cylindrical housing having a transverse hole penetrating the surrounding wall, A valve seat provided at the axial end of the housing, The housing comprises a valve body that is housed axially movable within the housing and is constantly biased to seat on the valve seat, The valve body is configured to move away from the valve seat to form a first opening which serves as the gas inlet and a second opening which serves as the gas outlet. The first opening is the gap between the valve seat and the tip of the valve body, and is configured to be opened and closed by the tip of the valve body. The second opening is a part of the lateral hole exposed inside the housing and is configured to be opened and closed by the outer circumferential surface of the valve body. Regardless of the position of the valve body, the opening area of ​​the second opening is configured to be smaller than the opening area of ​​the first opening. The tip of the valve body has a tapered surface that narrows towards the tip, and the valve seat has a tapered surface on which the tapered surface of the valve body sits. As the valve body moves, the tapered surface of the valve body overlaps radially with respect to the transverse hole, thereby forming the second opening. Furthermore, it includes an introduction space which is a space enclosed by the inner circumferential surface of the housing, the valve seat, and the tapered surface of the valve body. When the valve body moves away from the valve seat, the first opening is configured to open before the second opening, In the stage when the first opening begins to form, the opening area of ​​the first opening is set to a size such that the first opening functions as a throttle when the gas passes through the first opening and flows into the introduction space.

2. The check valve according to claim 1, wherein the size of the lateral hole is set such that, during the period from when the second opening begins to be formed until the opening area of ​​the second opening reaches its maximum, the extended surface obtained by virtually extending the tapered surface of the valve body does not intersect with the inner circumferential surface of the lateral hole.

3. The valve body has a biasing member that constantly biases the valve body so that it sits on the valve seat, The check valve according to claim 1 or claim 2, wherein the gas after passing through the second opening is configured to be supplied to a gas tank, and the pressure of the gas after passing through the second opening acts on the base end, which is the end of the valve body opposite to the tip.

4. The check valve according to claim 1 or claim 2, wherein the gas is high-pressure hydrogen gas, and the hydrogen gas, after passing through the second opening, is supplied to the gas tank of a fuel cell vehicle.

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