JP2002295703A - Valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a valve capable of completely preventing the falling of a fork, for example, when a pressure hose breaks. SOLUTION: A valve element 23 having an orifice flow channel 26 is mounted between a first flow channel 21a and a second flow channel 22a, and the first flow channel 21a is connected to the second flow channel 22a via the orifice flow channel 26 in a state where the valve element 23 is pressed onto a free flow seat part 25 formed at an opening edge of the second flow channel 22a by an elastic force of a spring 24. When fluid flows through the orifice flow channel 26 from the second flow channel 22a side to the first flow channel 21a side, the valve element 23 moves against the spring 24 and sits on a check seat part 27 side formed at an opening edge of the first flow channel 21a, thereby cutting off a connection between the first flow channel 21a and the second flow channel 22a. The valve having this function is provided with a closing holding structure for holding the sitting state of the valve element 23 on the check seat part 27.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve having a check function for interrupting a flow when a predetermined flow rate flows.

[0002]

2. Description of the Related Art FIG. 7 is a circuit diagram showing a lifting and lowering device for a fork F of a forklift. The rods 1a and 2a of the pair of cylinders 1 and 2 are connected to the fork F, respectively. The cylinders 1 and 2 are connected to a vehicle (not shown), and the first pipes 5 are connected to the bottom chambers 3 and 4 respectively. Note that a safety valve a is interposed between the bottom side chamber 3 of the cylinder 1 and the first pipe 5, and the safety valve a will be described later in detail.

[0003] A rubber pressure-resistant hose 6 is connected to the first pipe 5, and a second pressure-resistant hose 6 is connected through the pressure-resistant hose 6.
The pipe 7 is connected. The second pipe 7 is provided with a flow control valve 8 provided with an orifice flow path 11, and the front and rear of the flow control valve 8 are connected by a bypass flow path 9. The cylinders 1, 2 are provided in the bypass passage 9.
A check valve 10 that regulates the flow from the side is provided.
A switching valve 12 is connected to the second pipe 7, and a pump P is connected to the switching valve 12.

The switching valve 12 cuts off the communication between the pump P and the second pipe 7 when it is in the neutral position shown in the figure, but switches the pump P and the second pipe 7 when it is switched to the left position in the drawing. . If the pump P and the second pipe 7 are communicated in this way, the discharge oil of the pump P will be discharged from the switching valve 12 → the second pipe 7 → the bypass passage 9 → the check valve 10 → the pressure-resistant hose 6 →
Bottom chambers 3 and 4 of cylinders 1 and 2 via first pipe 5
Supplied to both. Therefore, the cylinders 1 and 2 extend, and the fork F rises.

On the other hand, when the switching valve 12 is switched to the right position in the drawing, the second pipe 7 communicates with the tank T. Therefore, the pressure oil in the bottom chambers 3 and 4 of the cylinders 1 and 2
Pipe 5 → pressure-resistant hose 6 → second pipe 7 → orifice flow path 11 of flow control valve 8 → discharged to tank T via switching valve 12. As a result, the cylinders 1 and 2 contract, and the fork F descends. When the fork F is lowered in this manner, the pressure oil is discharged through the orifice passage 11 of the flow control valve 8 so that the lowering speed of the fork F does not become extremely high. That is, when a heavy load W is placed on the fork F, the cylinders 1, 2
A large load pressure acts on the bottom side chambers 3 and 4. When such a large load pressure acts on the bottom chambers 3 and 4, the discharge flow rate also increases, and the lowering speed of the fork F becomes too fast. Therefore, when the fork F is lowered, the discharge flow rate is controlled by the flow rate control valve 8 to prevent the fork F from dropping sharply.

A safety valve a provided between the bottom chamber 3 of the cylinder 1 and the first pipe 5 is provided with a pressure-resistant hose 6.
This is to prevent the fork F from suddenly dropping when it is damaged. This safety valve is shown in FIG.
As shown in FIG. 1, the first member 13 having the first flow path 13a formed therein
, A second member 14 having a second flow path 14a formed therein is screwed. A valve body 15 and a spring 16 are incorporated between the first member 13 and the second member 14, and the spring 16
The right side end of the valve body 15 in the drawing is pressed against the free-flow seat portion 18 formed on the second member 14 by the elastic force of.

The valve body 15 has an orifice passage 17 formed therein. The orifice flow path 17 allows the first flow path 13a and the second flow path 14a to communicate with each other even when the right end of the valve body 15 is pressed against the free flow sheet portion 18 as shown in the figure. Further, while the check sheet portion 19 is formed on the first member 13,
The valve body 15 has a seat surface 20 formed thereon. When the valve body 15 moves leftward in the drawing, the seat surface 20 of the valve body 15
Is pressed against the check sheet portion 19. And, in this way, the valve body 15 is
By pressing the sheet surface 20, the communication between the first flow path 13a and the second flow path 14a is cut off.

[0008] The safety valve a as described above is
The bottom member 3 of the cylinder 1 is connected to the second member 14, and the first pipe 5 is connected to the first member 13. Then, for example, when the discharge oil of the pump P is guided to the first flow path 13a via the first pipe 5, the pressure oil passes through the orifice flow path 17 and is guided to the second flow path 14a. When the pressure oil passes through the orifice passage 17 in this manner, a pressure difference is generated across the orifice passage 17. Then, a thrust in the right direction in the drawing acts on the valve body 15 by the differential pressure. Therefore, the valve element 15 keeps its right end pressed against the free-flow seat portion 18. That is, the first
When the pressure oil flows from the member 13 side to the second member 14 side, the first flow path 13a and the second flow path 14a are kept in communication. Therefore, when raising the fork F, the oil discharged from the pump P is supplied to the cylinders 1 and 2 through the orifice passage 17.

On the other hand, the second member 1 is
When the flow is generated from the fourth side toward the first member 13, the magnitude relation of the differential pressure generated before and after the orifice flow path 17 is reversed, so that the thrust in the left direction in the drawing acts on the valve body 15. That is, the thrust in the direction of blocking the communication between the first flow path 13a and the second flow path 14a acts on the valve body 15. However,
If the thrust acting on the valve element 15 is smaller than the elastic force of the spring 16, the valve element 15 maintains the open state shown in the figure. Therefore, in this case, the pressure oil guided from the second member 14 is supplied to the first member 13 through the orifice passage 17.
Flows to the side. On the other hand, when the thrust in the closing direction acting on the valve body 15 becomes larger than the elastic force of the spring 16,
The valve body 15 moves to the left in the drawing against the spring 16 and presses the seat surface 20 against the check seat portion 19. Therefore, the communication between the first flow path 13a and the second flow path 14a is interrupted, and the pressure oil guided from the second member 14
It is not supplied to the first member 13 side.

Next, the operation and function of the safety valve a will be described. For example, when the pressure oil in the bottom chamber 3 of the cylinder 1 passes through the orifice passage 17 when the pressure-resistant hose 6 is broken, a thrust in the left direction in the drawing is applied to the valve body 15 by a differential pressure generated across the orifice passage 17. Works. The magnitude of the thrust acting on the valve element 15 is proportional to the magnitude of the differential pressure across the orifice flow path 17, and the magnitude of this differential pressure is proportional to the square of the flow rate passing through the orifice flow path 17. . Here, the flow rate passing through the orifice flow path 17 depends on the weight of the load W placed on the fork F,
The heavier the load W, the larger the flow rate through the orifice passage 17.

Therefore, when a heavy load W is placed on the fork F, a large thrust acts on the valve body 15 due to the large flow rate passing through the orifice passage 17. When a large thrust acts on the valve body 15 in this manner, the valve body 15 moves leftward overcoming the elastic force of the spring 16, and the seat surface 20 of the valve body 15 is pressed against the check seat portion 19. . Accordingly, the communication between the first flow path 13a and the second flow path 14a is interrupted, whereby the outflow of the pressure oil from the bottom chamber 3 of the cylinder 1 is restricted, and the drop of the fork F is stopped. That is, if the pressure-resistant hose 6 is damaged, the flow rate passing through the orifice passage 17 increases, and only in such a case, the safety valve a is switched to the shut-off state to prevent the fork F from falling. Like that.

[0012]

The above-mentioned conventional safety valve a has the following problems because it is closed or opened by a differential pressure generated before and after the orifice passage 17. For example, when the pressure-resistant hose 6 is cut off, the fork F falls until the safety valve a closes. Therefore, when the safety valve a closes, the fall of the fork F suddenly stops, causing a shock. . Due to this shock, an elastic member such as a tire bends, and the fork F sinks instantaneously. The sunken fork F rises next due to the recoil. At this time, the rods 1 of the cylinders 1 and 2 supporting the fork F
Since a and 2a are pulled in the extending direction, the load pressure on the bottom chambers 3 and 4 is reduced. When the load pressure of the bottom chambers 3 and 4 decreases, the pressure acting on the safety valve a also decreases, and the thrust acting on the valve body 15 in the closing direction also decreases. When the thrust acting on the valve element 15 in the closing direction becomes smaller than the elastic force of the spring 16, the valve element 15 opens by the action of the spring 16, and the pressure oil flows out again from the bottom chamber 3 of the cylinder 1. That is, the fork starts falling again.

When the fork F starts to fall as described above, a flow is generated again in the orifice passage 17. When the pressure difference across the orifice passage 17 reaches a predetermined value, the valve body 15 causes The flow path is shut off. Therefore, the fork F stops falling, but in this case, the same phenomenon as described above occurs due to the shock, and the safety valve a is opened again. Then, by repeating such a phenomenon, the fork F eventually descends to the lowest position. That is, in the conventional valve, when the pressure-resistant hose 6 is cut,
There is a problem that the fall of the fork F cannot be completely stopped. It is an object of the present invention to provide a valve that can completely stop the fork F from falling when the pressure-resistant hose is cut.

[0014]

According to a first aspect of the present invention, there is provided a first member having a first flow path, a second member having a second flow path, and an orifice provided between the first and second members. A valve body having a flow path, a check sheet portion formed at an opening edge of the first flow path, a free flow sheet portion formed at an opening edge of the second flow path, and a valve body formed at the free flow sheet portion A spring that presses the orifice flow while maintaining the first flow path and the second flow path in communication with each other through the orifice flow path when the valve body is pressed against the free flow sheet portion. When the thrust acting on the valve element is larger than the elastic force of the spring when the fluid flows from the second flow path side to the first flow path side in the path, the valve element moves against the spring, and the valve moves. When the body is seated on the non-return seat portion side, communication between the first flow path and the second flow path is established. In the valve to be cross, when the valve body is seated on the check sheet section, characterized by comprising a closed holding structure for holding a state where the valve body is seated.

According to a second aspect, in the first aspect,
The valve body is engaged in the check seat, and the retaining force generated by this engagement is made larger than the elastic force of the spring acting on the valve body, thereby forming a closed holding structure. It is characterized by. A third invention is characterized in that, in the first invention, the movement of the valve body pressed against the check sheet portion is restricted by a stopper member to constitute a closed holding structure.

According to a fourth aspect of the present invention, there is provided a first member having a first flow path, a second member having a second flow path, and a valve element having an orifice flow path between the first and second members. A check sheet portion formed at the opening edge of the first flow path, a free flow sheet portion formed at the opening edge of the second flow path, and a state where the valve is pressed against the free flow sheet portion. An opening / holding mechanism for maintaining the first and second flow paths in communication with each other via the orifice flow path when the valve body is pressed against the free flow sheet portion. When the thrust acting on the valve body becomes larger than the holding force of the open holding mechanism when the fluid flows from the second flow path side to the first flow path side of the path, the valve body moves, and the valve body moves. The communication between the first flow path and the second flow path is interrupted by sitting on the check sheet side. The features.

[0017]

1 and 2 show a first embodiment. FIGS. 1 and 2 are partially enlarged views in which the valve body 23 of the safety valve A is enlarged. FIG. 1 shows an open state, and FIG. 2 shows a closed state. As shown in FIG. 1, the first member 21 having the first flow path 21a is
The second member 22 forming the second flow path 22a is screwed. A valve 23 and a spring 24 are incorporated in a space formed between the first member 21 and the second member 22. By applying the elastic force of the spring 24 to the valve body 23, the right end of the valve body 23 in the drawing is pressed against the free-flow sheet portion 25 formed at the opening edge of the second flow path 22a.

An orifice passage 26 is formed in the valve body 23. Even when the valve element 23 is pressed against the free flow sheet portion 25 as shown in the drawing, the first flow path 21a and the second flow path 22
a. Further, a check sheet portion 27 is formed at the opening edge of the first flow path 21a of the first member 21. The angle θ1 between the surface of the check sheet 27 and the axis is set to an acute angle. On the other hand, a seat surface 28 is formed on the valve body 23. The angle θ2 between the seat surface 28 and the axis is also acute. And FIG.
When the valve element 23 moves to the left in the drawing as shown in FIG.
The seat surface 28 is made to bite into the check sheet portion 27. When the seat surface 28 of the valve element 23 is engaged in the check seat portion 27, the first flow path 21a and the second flow path 22
Communication with a is cut off.

Also, as described above, the seat surface 28 of the valve body 23
Into the check seat 27, the spring 24
The valve body 23 is prevented from falling out of the check seat portion 27 only by the elastic force of (1). Specifically, the check sheet portion 27
The retaining force, which is the maximum static frictional force between the spring 24 and the seat surface 28, is set to be greater than the elastic force of the spring 24 in the bent state. That is, in the first embodiment, the valve 23 is held in the check seat 27 so that the communication between the first flow path 21a and the second flow path 22a can be maintained in a disconnected state. . In the safety valve A, as shown in FIG. 7, the bottom member 3 of the cylinder 1 is connected to the second member 22, and the first pipe 5 is connected to the first member 21.

Next, the operation of the first embodiment will be described.
For example, when the pressure oil in the bottom chamber 3 of the cylinder 1 passes through the orifice flow path 26 due to breakage of the pressure-resistant hose 6 or the like, the valve 2
3, a thrust in the left direction of the drawing acts. The magnitude of the thrust acting on the valve element 23 is proportional to the magnitude of the differential pressure across the orifice flow path 26, and the magnitude of this differential pressure is proportional to the square of the flow rate passing through the orifice flow path 26. . Here, the flow rate passing through the orifice flow path 26 depends on the weight of the load W placed on the fork F. As the load W increases, the flow rate passing through the orifice flow path 26 increases.

Therefore, when a heavy load W is placed on the fork F, a large thrust acts on the valve body 23 due to the large flow rate passing through the orifice passage 26. When a large thrust acts on the valve body 23 in this manner, the spring 2
The valve body 23 moves to the left by overcoming the elastic force of No. 4 and the seat surface 28 is bitten into the check seat portion 27 to cut off the communication between the first flow path 21a and the second flow path 22a. I do. Therefore, the outflow of the pressure oil from the bottom side chamber 3 of the cylinder 1 is restricted, and the drop of the fork F is stopped.

Also, as described above, the seat surface 2 of the valve body 23
8 is set to be greater than the elastic force of the spring 24, the valve body 23 is non-returnable only by the elastic force of the spring 24. It does not fall out of the seat 27. Therefore, even if the load pressure acting on the valve body 23 is reduced by the shock generated when the fork F stops falling, the valve body 23 does not fall out of the check seat 27. That is, once the communication between the first flow path 21a and the second flow path 22a is interrupted, the closed state can be maintained. Therefore, according to the first embodiment, it is possible to completely prevent the fork F from falling. In addition, since no special parts are required, it is advantageous in terms of cost.

When returning from the state shown in FIG. 2 to the state shown in FIG. 1 after repairing the pressure-resistant hose 6, the pressure oil of the pump P is supplied to the first flow path 23a, and the valve body 23 is turned off. Remove from the biting state. In this way, the valve body 23 can be returned to the open state shown in FIG. 1 by the elastic force of the spring 24.

In the second embodiment shown in FIGS. 3 and 4, an annular groove 29 is formed on the inner periphery of the second member 22, and an annular elastic ring 30 is fitted into the annular groove 29. The elastic ring 30 corresponds to the stopper member of the present invention, and is pressed against the side surface 23a of the valve body 23 when the valve body 23 moves leftward in the drawing as shown in FIG. The elastic ring 30 regulates the movement of the valve body 23. That is, in the second embodiment, the valve body 23 once closed by the elastic ring 30 is moved only by the elastic force of the elastic ring spring 24 as shown in FIG.
To prevent it from returning to the open state.

The side surface 23a of the valve body 23 is formed with a tapered surface 23b. This tapered surface 23b is
This is for gradually pushing the elastic ring 30 in the radial direction when the valve body 23 moves to the left. Note that this second
In the embodiment, unlike the first embodiment, the valve body 23 does not bite into the check seat portion 28. That is, the communication between the first flow path 21a and the second flow path 22a is interrupted by pressing the seat surface 28 of the valve body 23 against the check seat portion 28.

Next, the operation of the second embodiment will be described.
When a large flow rate passes through the orifice passage 26 due to breakage of the pressure-resistant hose 6 and the thrust acting on the valve body 23 becomes larger than the elastic force of the spring 24, the valve body 23 is moved from the state shown in FIG. Start moving to the left. Then, the elastic ring 30 is connected to the annular groove 2 by the side surface 23a of the valve body 23.
9, the sheet surface 28 is pressed against the non-return seat portion 27 as shown in FIG. When the sheet surface 28 is pressed against the check sheet 27, the communication between the first flow path 21a and the second flow path 22a is cut off. Therefore, the outflow of the pressure oil from the bottom side chamber 3 of the cylinder 1 is regulated, and the fall of the fork F is stopped.

At this time, the side surface 23a of the valve body 23
Further, by pressing the elastic ring 30, the valve body 23 is restricted so as not to move only by the elastic force of the spring 24. Therefore, even if the load pressure acting on the valve body 23 is reduced by the shock generated when the fork F stops falling, the seat surface 28 of the valve body 23
Does not separate from the check sheet 27. That is, once the communication between the first flow path 21a and the second flow path 22a is interrupted, the closed state can be maintained by the elastic ring 30. Therefore, according to the second embodiment, it is possible to completely prevent the fork F from falling. In the second embodiment, the elastic ring 30 is pressed against the valve element 23 to restrict the movement of the valve element 23. Therefore, the force for restricting the movement of the valve element 23 can be set freely. Can be.

In the second embodiment, the stopper member of the present invention is constituted by the elastic ring 30. However, any stopper member can be used as long as the movement of the valve body 23 can be restricted. Good. When the pressure-resistant hose 6 is restored from the closed state shown in FIG. 4 to the open state shown in FIG. 3 after the repair, the high pressure may be applied from the first flow path 21a side. If a high thrust is applied to the valve body 23 by this high pressure, which is greater than the holding force of the elastic ring 30, the valve body 23 moves rightward. When the side surface of the valve body 23a moves to a position where it comes off the elastic ring 30,
3 can be returned to the open state by the elastic force of the spring 24.

The third embodiment shown in FIGS.
The spring 24 of the embodiment is omitted, and the valve 23 is held open by the elastic ring 31. In the third embodiment, the annular groove 32 is formed closer to the free flow sheet portion 25 than in the second embodiment, and the annular elastic ring 31 is fitted in the annular groove 32. Then, by pressing the elastic ring 31 against the side surface 23a of the valve body 23, the open state shown in FIG. 5 is maintained. That is, in the third embodiment, the elastic ring 31 constitutes the holding mechanism of the present invention. Further, a tapered surface 23c is formed on a side surface 23a of the valve body 23. The tapered surface 23c is for gradually pushing the elastic ring 31 in the radial direction when the valve body 23 is set in the state shown in FIG.

Next, the operation of the third embodiment will be described.
When a large flow rate passes through the orifice flow path 26 due to breakage of the pressure-resistant hose 6 and the like, and the thrust acting on the valve body 23 becomes larger than the holding force of the elastic ring 31, the valve body 23 is moved to the state shown in FIG.
Starts to move rightward in the drawing from the state shown in FIG. When the elastic ring 31 comes off from the side surface 23a of the valve body 23, the seat surface 28 of the valve body 23 is pressed against the check seat 27 as shown in FIG. Thus, the sheet surface 28
Is pressed against the check sheet 27, the first flow path 21a
Communication with the second flow path 22a is interrupted. Therefore,
The outflow of pressure oil from the bottom chamber 3 of the cylinder 1 is regulated, and the fork F stops falling.

At this time, the elastic force of the spring 24 does not act on the valve body 23 as in the first and second embodiments. Therefore, even if the load pressure acting on the valve body 23 is reduced by the shock generated when the fork F stops falling, the seat surface 28 of the valve body 23 does not separate from the check seat 27. That is, the first flow path 21
Once the communication between a and the second flow path 22a is interrupted, the closed state can be maintained. Therefore, also according to the third embodiment, it is possible to completely prevent the fork F from falling. Further, in the third embodiment, the cost can be reduced by eliminating the need for the spring.

In the third embodiment, the elastic ring 3
1, the holding mechanism of the present invention is configured. However, the configuration is not limited as long as it has a function capable of holding the open state of the valve body 23. When returning from the closed state shown in FIG. 6 to the open state shown in FIG. 5, pressure oil is supplied from the pump P, or a rod or the like is inserted from the first flow path 21a side. What is necessary is just to push the valve body 23.

[0033]

According to the first to third aspects of the present invention, when the valve body is seated on the check seat portion, the state where the valve body is seated can be maintained by the closed holding structure. Therefore, the fall of the fork F can be completely stopped. According to the second aspect of the present invention, since the valve body is engaged in the check seat portion to form the closed holding structure, the cost of parts can be reduced because the stopper member is not required. According to the third aspect, since the movement of the valve element pressed against the check sheet portion is restricted by the stopper member, the force for restricting the movement of the valve element can be set freely.

According to the fourth aspect of the present invention, since no spring is used, when the valve body is seated on the non-return seat portion, the force for releasing the state does not act on the valve body. Therefore, the state where the first flow path and the second flow path are shut off can be maintained, and the fall of the fork F and the like can be completely stopped. Further, according to the fourth aspect, since no spring is used, the cost can be reduced accordingly.

[Brief description of the drawings]

FIG. 1 is a view showing a first embodiment, and is a cross-sectional view showing a state where a first flow path 21a and a second flow path 22a are communicated.

FIG. 2 is a view showing the first embodiment, and is a cross-sectional view showing a state in which communication between a first flow path 21a and a second flow path 22a is interrupted.

FIG. 3 is a view showing a second embodiment, and is a cross-sectional view showing a state where a first flow path 21a and a second flow path 22a are communicated with each other.

FIG. 4 is a view showing the second embodiment, and is a cross-sectional view showing a state in which communication between the first flow path 21a and the second flow path 22a is cut off.

FIG. 5 is a view showing a third embodiment, and is a cross-sectional view showing a state in which a first flow path 21a and a second flow path 22a are communicated.

FIG. 6 is a view showing a third embodiment, and is a cross-sectional view showing a state in which communication between a first flow path 21a and a second flow path 22a is cut off.

FIG. 7 is a circuit diagram showing a device for controlling a fork F of a forklift.

FIG. 8 is a sectional view of a conventional example.

[Explanation of symbols]

Reference Signs List 21 first member 21a first flow path 22 second member 22a second flow path 23 valve body 24 spring 25 free flow seat part 27 check seat part 30 elastic ring corresponding to stopper member of the present invention 31 open holding of the present invention Elastic ring that constitutes the mechanism

Continued on the front page F term (reference) 3H060 AA02 CC07 DC05 DC10 DD02 DD14 EE05 HH04 HH18 3H089 BB12 BB28 CC01 DA02 DB13 DB33 GG02 JJ09

Claims (4)

[Claims] A first member having a first passage, a second member having a second passage, a valve having an orifice passage between the first member and the second member, A check sheet formed at an opening edge of the first flow path, a free flow sheet formed at an opening edge of the second flow path, and a spring pressing a valve body against the free flow sheet; When is pressed against the free flow sheet portion, the first flow path and the second flow path are kept in communication with each other through the orifice flow path, and the fluid flows into the orifice flow path from the second flow path side. When the thrust acting on the valve element becomes larger than the elastic force of the spring when flowing to the one flow path side, the valve element moves against the spring and the valve element is seated on the check seat side. In the valve in which the communication between the first flow path and the second flow path is cut off, A valve comprising a closed holding structure for holding a state in which the valve body is seated when the valve body is seated on the check seat portion. 2. The valve body is fitted into the check sheet portion, and the retaining force generated by the engagement is made larger than the elastic force of the spring acting on the valve body, thereby keeping the valve body closed. The valve according to claim 1, wherein the valve has a structure. 3. The movement of the valve body pressed against the check seat portion is regulated by a stopper member,
The valve according to claim 1, wherein a closed holding structure is configured. 4. A first member having a first flow path, a second member having a second flow path, a valve having an orifice flow path between the first member and the second member, A check sheet portion formed at an opening edge of one flow path, a free flow sheet portion formed at an opening edge of the second flow path, and an open holding mechanism for keeping a valve body pressed against the free flow sheet portion; When the valve body is pressed against the free flow sheet portion, the first flow path and the second flow path are kept in communication with each other via the orifice flow path, and the orifice flow path is kept in the second flow path. First from the channel side
When the thrust acting on the valve body when the fluid flows to the flow path side is larger than the holding force of the open holding mechanism, the valve body moves and the valve body is seated on the check seat side. The communication between the first flow path and the second flow path is interrupted by the valve.