JPH09210218A - Valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a valve which eliminates the possibility of damage to a seal member. SOLUTION: This valve is composed of a valve element which is provided with a wall inner surface 2b serving as a valve seat having a communicating hole 9 through which fluid flows, and which is also provided with an annular seal member 15 fitted to a cylindrical supporter 12a and the outer periphery thereof. The seal member 15 is elastically deformed by being in contact with the wall inner surface 2b so as to block the communicating hole 9. In this case, the seal member 15 has an escape 18 on the side of the inner periphery of a seal member end part 15b on the side of the wall inner surface 2b, and the slidable supporter 12a extends inside the communicating hole 9, and a slit 17 extending toward a supporter end part 12aa on the side of the wall inner surface 2b in an axial direction of the supporter 12a is formed in the outer periphery of the supporter 12a. The slit 17 extends from a position apart from a contact point of the seal member 15 with the wall inner surface 2b toward the supporter end part 12aa, in a condition where the seal member 15 stretches to the maximum length in a direction of the wall inner surface 2b on the outer periphery of the supporter 12a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve having an annular seal member, and more particularly to a valve used in a master cylinder or the like used in a hydraulic brake system for automobiles.

[0002]

2. Description of the Related Art A conventional valve is the actual open valve 62-2096.
As disclosed in Japanese Unexamined Patent Publication No. 2 (1994), a valve seat having a communication hole which is a fluid passage, and a support body and an outer periphery of the support body, which are elastically deformed by coming into contact with the valve seat, the communication hole. In a valve having a valve body composed of an annular seal member for closing the valve, the surface of the support body facing the valve seat is a flat surface, and the outer peripheral end of the surface of the support body facing the valve seat is It is pointed.

In this conventional valve, the valve body is brought into contact with the valve seat, the seal member is elastically deformed in the axial direction of the seal member, and the communication hole is shielded. The communication hole can be communicated by separating from the valve seat.

[0004]

However, in the recent hydraulic brake systems for automobiles, there is a tendency that complicated hydraulic devices such as ABS (anti-brake lock system) and TRC (traction control system) are added. When a conventional valve described above is used in a hydraulic brake system for an automobile to which a device such as ABS is added, when the valve body comes into contact with the valve seat to block the communication hole, the device such as ABS is There is a case in which the fluid pressure on the valve body side becomes higher than the fluid pressure on the communication hole side due to the operation of the device such as the ABS. When the fluid pressure on the valve body side becomes higher than the fluid pressure on the communication hole side, the high pressure biases the seal member of the valve body inward in the radial direction of the seal member. When the valve body separates from the valve seat when the fluid pressure on the valve body side is high,
Due to the pressure applied to the seal member inward in the radial direction of the seal member, the fluid on the valve body side further flows toward the communication hole, and the fluid flows to the communication hole. The seal member is pressed and urged inward in the radial direction of the seal member, and the seal member falls inward in the radial direction of the seal member with the sharp outer peripheral end of the surface of the support facing the valve seat as a fulcrum. However, there is a possibility that a portion of the support member on the inner peripheral side of the seal member, which comes into contact with the sharp outer peripheral end of the surface of the support member facing the valve seat, is damaged.

Further, when the valve body comes into contact with the valve seat in a state where the fluid pressure on the valve body side is high and the seal member falls down, the seal member causes the flat surface of the support body to face the valve seat and the valve seat. By being sandwiched, the seal member receives a pressing force by the fluid in the valve seat direction acting on the valve body via the support body,
There is a risk that the seal member may be crushed and damaged. An object of the present invention is to provide a valve in which there is no risk of damage to the seal member.

[0006]

In order to solve the above technical problems, a valve seat having a communication hole which is a fluid passage, a columnar support, and a valve fitted to the outer periphery of the support are provided. In a valve having a valve body having an annular seal member that elastically deforms by contacting a seat and closes the communication hole, the seal member is allowed to escape to the inner peripheral side of the end portion of the seal member on the valve seat side. The support body extends into the communication hole and is slidable in the communication hole, and an outer periphery of the support body has a support body end portion on the valve seat side in the axial direction of the support body. Is formed on the outer periphery of the support body than the contact portion between the seal member and the valve seat in the state in which the seal member is maximally extended in the valve seat direction. A valve characterized in that the valve is provided from a position separated from the end of the support.

[0007] Preferably, the slit is composed of a small slit and a large slit continuous from the small slit from the side of the seal member. In the valve according to the first aspect of the invention, since the support body slidably extends in the communication hole, the valve body is guided by the support body and the communication hole to move in the axial direction of the communication hole, Contacts the valve seat and elastically deforms the seal member to shield the communication hole. Further, the valve body is disengaged from the valve seat, and the communication hole can be communicated through the clearance between the support body and the communication hole and the slit.

When the seal member of the valve element is in contact with the valve seat and the communication hole is shielded, the fluid pressure on the valve element side becomes higher than the fluid pressure on the communication hole side, and this high pressure causes the valve element to be closed. When the seal member of Fig. 6 is biased inward in the radial direction of the seal member and the valve body tries to separate from the valve seat in this high pressure state, the valve body moves in the direction of separating from the valve seat. By moving, the resistance of the fluid on the valve body side is received and the seal member is pressed and biased toward the valve seat. The valve body and the valve seat are still in contact with each other, and the seal member is pressed and biased toward the valve seat, so that the end of the seal member on the valve seat side is slightly inward in the radial direction of the seal member. I fall down,
Since the relief is provided on the inner peripheral side of the end of the seal member, the end of the seal member does not bite into the clearance between the communication hole and the support.

Further, in the state where the seal member is pressed and urged toward the valve seat, extends the maximum toward the valve seat, and is in contact with the valve seat, the slit is located on the outer periphery of the support member and the seal member is maximized toward the valve seat. Since the seal member and the valve seat, which are extended to each other, are provided at a position farther to the end portion side of the support than the contact portion, the end portion of the seal member does not easily slip into the slit.

When the valve body is further moved in the direction away from the valve seat, the seal member is separated from the valve seat and the slit is exposed from the communication hole into the space on the valve body side, and the fluid on the valve body side is supported by the communication hole. It becomes possible to flow into the clearance with the body and into the slit, and the fluid flowing into the clearance between the communication hole and the support and into the slit flows into the communication hole. The pressure applied to the seal member inward in the radial direction of the seal member, and further, the flow of the fluid on the valve body side into the communication hole causes the seal member to move inward in the radial direction of the seal member. However, since the seal member is fitted to the outer circumference of a cylindrical support body that extends in the communication hole and is slidable in the communication hole, the seal member is sealed. It does not fall inward in the radial direction of the member.

Next, when the fluid pressure on the valve body side is higher than the fluid pressure on the communication hole side and the valve body is forcedly released from the state in which the valve body is forcibly released, the valve body is pushed again to the valve seat. The sealing member comes into contact with the valve seat to block the communication hole. When the seal member comes into contact with the valve seat, the pressure acting on the seal member inward in the radial direction of the seal member and the fluid on the valve body side are flowing toward the communication hole. As a result, the seal member is pressed and urged inward in the radial direction of the seal member so that the end portion of the seal member slightly collapses inward in the radial direction of the seal member. Since the relief is provided on the side, the inner peripheral side of the end of the seal member does not bite into the clearance between the communication hole and the support when the seal member contacts the valve seat.

According to the valve of the second aspect, in addition to the action of the first aspect, the valve body comes into contact with the valve seat to elastically deform the seal member to shield the communication hole. Further, the valve body is separated from the valve seat, and the communication hole can be communicated with each other through the clearance between the support body and the communication hole and the small slit and the large slit.

When the valve element is further pushed in the direction toward the valve seat and extends in the valve seat direction to the maximum extent and is in contact with the valve element, when the valve element is further moved away from the valve seat, the valve seal member The small slit separates from the seat and is exposed from the communication hole to the space on the valve body side, and the fluid on the valve body side can flow into the clearance between the communication hole and the support body and into the small slit, and the clearance between the communication hole and the support body. The fluid flowing into the small slits flows to the large slits and then to the communication holes. The flow rate of the fluid toward the communication hole when the small slit is exposed from the communication hole to the valve body side space is small because the flow rate is limited by the small slit, and therefore the fluid on the valve body side flows toward the communication hole. As a result, the end of the seal member of the seal member is not pressed and urged inward in the radial direction of the seal member, and the end of the seal member does not easily slip into the small slit. When the valve body is further moved away from the valve seat, the large slit is exposed from the communication hole to the space on the valve body side, and the fluid on the valve body side clears the communication hole and the support body, and the small slit and the large slit. The fluid can flow into the slit, and the fluid flowing into the clearance between the communication hole and the support and the small slit and the large slit flows into the communication hole. When this large slit is exposed from the communication hole to the space on the valve body side, the flow rate of the fluid on the valve body side toward the communication hole increases because the fluid can also flow into the large slit, and the fluid smoothly flows into the communication hole. Can flow.

[0014]

Embodiments of the present invention will be specifically described below.

As shown in FIG. 1, reference numeral 1 denotes a brake master cylinder used in an automobile brake system to which an ABS device is added. Inside a cylinder body 2, pistons having ring-shaped cup seals 4 and 5 mounted on the outer periphery thereof are mounted. 3 is slidably and liquid-tightly fitted.
A pressure chamber 6 is formed between the end wall 2 a of the cylinder body 2 and the end wall 2 a of the cylinder body 2. The pressure chamber 6 communicates with an actuator forming an ABS device (not shown) formed in the cylinder body 2 and a discharge port 7 communicating with a wheel cylinder. In the pressure chamber 6, a return spring 8 of the piston 3 and a communication hole formed in the end wall 2a of the cylinder body 2 in accordance with the operation (left sliding in FIG. 1) and return of the piston 3 are formed. A valve 10 for blocking and communicating with a reservoir (not shown) via 9 is arranged.

FIG. 2 is an enlarged view of the vicinity of the valve 10 portion of FIG. 1, and FIG. 3 is an enlarged view of the vicinity of the seal member 15 portion of FIG. As shown in FIGS. 2 and 3, the valve 10 includes an inner surface 2b serving as a valve seat of the end wall 2a of the cylinder body 2, a valve body 11, and a return spring 8 which fits the end wall 2a of the cylinder body 2. A case 13 which is pressed against the inner surface 2b and slidably supports the rod 12 and thus the valve body 11, and a case 13 which is disposed in the case 13 and which uses the rod 12 and thus the valve body 11 as a valve seat (left in FIG. 2). And a spring 14 for urging the same.

The valve element 11 is composed of a rod 12 and a rubber-made annular seal member 15 which is fitted to the rod 12 and elastically deforms by contacting the inner surface 2b to shield the communication hole 9. The rod 12 includes a support 12a and an engaging portion 12
b, the main body portion 12c, and the enlarged portion 12d are integrally provided, and the seal member 15 has an inner flange portion 15a.
It is assembled to the rod 12 by being fitted to the outer periphery of the rod 2a and the inner flange portion 15a being elastically engaged with the engaging portion 12b.

The support 12a of the rod 12 has a columnar shape with substantially the same diameter as the communication hole 9 and extends into the communication hole 9 to extend into the communication hole 9.
It is slidable inside. Therefore, the rod 12, and thus the valve body 11, is guided by the support body 12 a and the communication hole 9 to move in the axial direction of the communication hole 9. Support 12
A slit 17 is formed on the outer periphery of a so as to extend to the support body end portion 12aa on the inner wall end surface 2b side in the axial direction of the support body 12a.

The slit 17 is provided from the seal member 15 side.
The seal member 15 is composed of a small slit 17a and a large slit 17b continuous with the small slit 17a. As will be described later, on the outer periphery of the support 12a, the seal member 15 is in a state in which the seal member 15 extends in the maximum direction toward the inner wall surface 2b. End 15b
End 12aa of the support body rather than the contact portion between the inner surface 2b and the wall surface 2b
It is provided from a site separated by a length L ₁ on the side. The seal member 15 has a relief 18 on the inner peripheral side of the seal member end portion 15b.

The rod 12 has an enlarged portion 1 at the right end in FIG.
2d, the enlarged portion 12d is slidably inserted into the axial hole 3a of the piston 3, and the piston 3
The retainer 16 is fixed to the shaft to prevent the retainer 16 from coming off the axial hole 3a.

Next, the operation will be described. FIG. 4 is an enlarged view of the vicinity of the seal member 15 when the valve 10 is opened when the pressure chamber 6 is in a high pressure state. As shown in FIGS. 1 to 4, in the non-operating state of the master cylinder 1 of FIG.
The valve body 11 is separated from the inner surface 2b of the end wall, and the reservoir and the pressure chamber 6 have a communication hole 9, a clearance between the outer periphery of the support body 12a and the communication hole 9, and the slit 1 of the support body 12a.
Brake fluid can be communicated with the brake fluid. When the master cylinder 1 is operated in which the piston 3 is pushed leftward in FIG. 1 by the push rod 19, as is well known, the rod 12 and the valve body 11 are moved by the spring 14 in conjunction with the operation of the piston 3 in FIG. The seal member 15 of the valve body 11 is moved to the left and the end wall 2 a of the cylinder body 2 is moved.
Of the seal member 15 by contacting the inner surface 2b of the seal member 15.
The communication hole 9 and the pressure chamber 6 are liquid-tightly shielded while elastically deforming in the axial direction of 5. After that, the piston 3 is further operated, so that the brake fluid in the pressure chamber 6 is pressurized and discharged from the discharge port 7. When the push rod 19 releases the pressing of the piston 3, the return spring 8 slides the piston 3 to the right in FIG. At this time, if the pressure in the pressure chamber 6 becomes negative, the seal member 15 separates from the inner surface 2b of the end wall due to the pressure difference between the communication hole 9 and the pressure chamber 6, and the brake fluid in the reservoir (not shown) is in the pressure chamber 6. Be pumped into. Then, when the piston 3 returns to the return position of FIG. 1, the enlarged portion 12d of the rod 12 and the retainer 16
The rod 12 is forced to the position shown in FIG. 1 due to the engagement with and the seal member 15 is kept separated from the inner surface 2b of the end wall, and the pressure chamber 6 communicates with the reservoir.

During operation of the master cylinder 1, that is, the valve body 1
The seal member 15 of No. 1 comes into contact with the inner surface 2b of the end wall and the communication hole 9
When the ABS device (not shown) is actuated when the pressure chamber 6 and the pressure chamber 6 are shielded, the brake fluid pressure on the valve body 11 side, that is, the brake fluid pressure in the pressure chamber 6 is the brake fluid on the communication hole 9 side. The hydraulic pressure is higher than the hydraulic pressure of the reservoir. When the brake fluid pressure in the pressure chamber 6 becomes higher than the brake fluid pressure on the communication hole 9 side, the high pressure biases the seal member 15 of the valve body 11 inward in the radial direction of the seal member 15. become. When the pressure of the piston 3 is forcibly released by the push rod 19 when the pressure chamber 6 is in a high pressure state, the return spring 8 slides the piston 3 to the right in FIG. Returning to the position, the rod 12 is forced to the position shown in FIG. 1 due to the engagement between the enlarged portion 12d of the rod 12 and the retainer 16, and the seal member 15 tries to separate from the inner surface 2b of the end wall. When the seal member 15 is about to be separated from the inner surface 2b of the end wall, as shown in FIG. 4, the rod 12 moves to the right in the figure and receives the resistance of the brake fluid in the pressure chamber 6 to cause the seal member 15 to move to the wall surface. It is pressed and urged in the direction of the inner surface 2b. When the seal member 15 is pressed and biased toward the inner surface 2b of the wall surface, the seal member end portion 15b of the seal member 15 slightly falls inward in the radial direction of the seal member 15, but the inner peripheral side of the seal member end portion 15b. Since the relief 18 is provided in the seal member, the seal member end portion 15b does not penetrate into the clearance between the communication hole 9 and the outer periphery of the support body 12a.

Further, when the seal member 15 is pressed and urged toward the wall surface inner surface 2b and the seal member 15 extends to the wall surface inner surface 2b direction to the maximum extent and abuts, the slit 1
7, that is, the small slit 17a is separated from the portion of the support body 12a, which is separated from the support body end portion 12aa by the length L ₁ from the portion where the inner wall surface 2b of the support body 12a is in contact with the seal member end portion 15b. Since it is provided, this seal member 1
In the state in which 5 is maximally extended in the wall surface inner surface 2b direction and is in contact with the wall surface 2b, the seal member end portion 15b has the small slit 17a.
It's not difficult to get in.

Further, the rod 12 and, by extension, the valve body 11 are shown in FIG.
When it is moved to the right in the middle by the length L ₁ , the seal member 15 is separated from the inner wall surface 2b, and the small slit 17a is formed into the communication hole 9.
To the pressure chamber 6, and the brake fluid in the pressure chamber 6 can flow into the clearance between the communication hole 9 and the outer periphery of the support body 12a and into the small slit 17a. Clearance and small slit 17
The brake fluid that has flowed into the inside of the “a” flows into the reservoir through the large slit 17b and, eventually, the communication hole 9. The flow rate of the brake fluid toward the communication hole 9 when the small slit 17a is exposed to the pressure chamber 6 is small because the flow rate is limited by the small slit 17a, and therefore, the brake fluid in the pressure chamber 6 enters the communication hole 9. The seal member end portion 15b of the seal member 15 is not pressed and urged inward in the radial direction of the seal member 15 due to the flowing toward the seal member 15, and the seal member end portion 15b does not easily fit into the small slit 17a. There is no.

Further, the rod 12 and, by extension, the valve body 11 are shown in FIG.
When moved to the middle right, the large slit 17b is exposed from the communication hole 9 to the pressure chamber 6, and the brake fluid in the pressure chamber 6 is cleared from the communication hole 9 and the outer periphery of the support 12a, and the small slit 17a. And it becomes possible to flow into the large slit 17b,
The clearance between the communication hole 9 and the outer periphery of the support 12a, and the brake fluid that has flowed into the small slit 17a and the large slit 17b flows to the reservoir via the communication hole 9. The flow rate of the brake fluid toward the communication hole 9 when the large slit 17b is exposed to the pressure chamber 6 increases because the brake fluid can also flow into the large slit 17b, so that the brake fluid can smoothly flow into the communication hole 9 and eventually the communication hole 9. Can flow to the reservoir. The pressure applied to the seal member 15 inward in the radial direction of the seal member 15, and further, the flow of the brake fluid in the pressure chamber 6 to the communication hole 9 causes the seal member 15 to move. Is pressed and urged inward in the radial direction of the
The seal member 1 is fitted to the outer periphery of the cylindrical support 12a that extends inside and is slidable in the communication hole 9.
5 does not fall inward in the radial direction of the seal member 15.

Further, when the pressure rod 6 pushes the piston 3 to the left again from the state where the pressure chamber 6 is in a high pressure state and the valve body 11 is forcibly released, the valve body 1
The seal member 15 of No. 1 abuts on the inner surface 2b of the end wall to make the communication hole 9
Then, the pressure chamber 6 is cut off. When the seal member 15 comes into contact with the inner surface 2b of the end wall, the seal member 15
The pressure urging the seal member 15 inward in the radial direction acting on the seal member 15 and the brake fluid in the pressure chamber 6 flowing toward the communication hole 9
Is pressed and urged inward in the radial direction of the seal member 15 so that the seal member end portion 15b is slightly collapsed inward in the radial direction of the seal member 15, but the inner periphery of the seal member end portion 15b is Since the relief 18 is provided on the side, the inner peripheral side of the seal member end portion 15b is in contact with the inner surface 2b of the end wall of the seal member 15 at the communication hole 9 and the support body 12a.
It does not bite into the clearance with the outer circumference.

As described above, according to the valve of this embodiment, the seal member 15 extends into the communication hole 9 and is slidable in the communication hole 9, and the outer periphery of the cylindrical support 12a. The seal member 15 does not fall inward in the radial direction because it is fitted to the seal member 1. Therefore, the seal member 15 is not likely to be damaged.

Further, in the seal member 15, since the escape 18 is provided on the inner peripheral side of the seal member end portion 15b, the seal member end portion 15b does not easily fit into the small slit 17a, and the communication hole 9 and the support hole 9 are supported. The clearance with the outer circumference of the body 12a does not enter, and therefore the seal member 15 is not likely to be damaged.

Further, the slit 17 is formed on the outer periphery of the support 12.
Is provided from a portion separated from the contact portion between the inner wall surface 2b and the seal member end portion 15b by the length L ₁ on the support body end portion 12aa side, the seal member end portion 15b is
The small slit 17a, that is, the slit 17 does not easily fit into the small slit 17a, and therefore the seal member 15 is not likely to be damaged.

Further, since the slit 17 is composed of a small slit 17a and a large slit 17b continuous with the small slit 17a from the seal member 15 side, the seal member end portion 15b of the seal member 15 has an end wall. When it is in the vicinity of the inner surface 2b, the flow rate becomes slow because the inflow amount of the brake fluid into the communication hole 9 is limited, and the end of the seal member accompanying the flow of the brake fluid in the pressure chamber 6 into the communication hole 9 is closed. Part 15b
The urging force of the seal member 15 inward in the radial direction is weakened, and the seal member end portion 15b is prevented from entering the clearance between the communication hole 9 and the outer periphery of the support body 12a and the small slit 17a, and the seal member 15 is securely inserted. When it is completely away from the inner surface 2b of the end wall, the amount of the brake fluid flowing into the communication hole 9 can be increased, and the brake fluid can smoothly flow to the communication hole 9 and further to the reservoir.

Therefore, it is possible to provide a valve in which the seal member 15 is not damaged.

In the present embodiment, the valve of the present invention is adopted in the single type brake master cylinder, but the present invention is not limited to this, and it is applicable to various valve mechanisms such as a tandem type portless brake master cylinder. Needless to say, even if the valve of the invention is adopted, the same effect can be obtained.

Further, in the present embodiment, the support 12
Although one slit 17 is provided on the outer periphery of a,
Needless to say, similar effects can be obtained even in a valve having a plurality of slits in the support.

Although the present invention has been described based on the above embodiments, the present invention is not limited to the above embodiments and includes various embodiments according to the principle of the present invention.

[0035]

As described above, according to the first aspect of the invention, the cylindrical support member extends into the communication hole and is slidable in the communication hole. Since the seal member is fitted, the seal member does not fall inward in the radial direction of the seal member, and furthermore, in the seal member, the relief is provided on the inner peripheral side of the end portion of the seal member. , The end of the seal member does not penetrate into the slit and the clearance between the communication hole and the support, and further, the slit in the support causes the end of the seal member in the state where the seal member extends to the valve seat direction to the maximum extent. Since it is provided at a position closer to the end portion of the support than the position of the abutting portion between the portion and the valve seat, the end portion of the seal member does not easily slip into the slit,
Therefore, it is possible to provide a valve in which there is no risk of damage to the seal member.

According to the invention of claim 2, in addition to the effect of the invention of claim 1, the slit is composed of a small slit and a large slit continuous to the small slit from the sealing member side. When the end of the seal member of the seal member is in the vicinity of the valve seat, the flow rate becomes slow because the amount of fluid flowing into the communication hole is limited, and the end of the seal member accompanying the flow of fluid into the communication hole Since the urging force of the seal member inward in the radial direction of the seal member is weakened, the end of the seal member does not enter the clearance between the communication hole and the support and the small slit, and the seal member does not move completely away from the valve seat. When
The amount of fluid flowing into the communication hole can be increased, and the fluid can smoothly flow into the communication hole. Therefore, it is possible to provide a valve in which there is no risk of damage to the seal member.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a master cylinder according to an embodiment.

FIG. 2 is a partially enlarged sectional view of FIG.

FIG. 3 is a partially enlarged sectional view of FIG.

FIG. 4 is an enlarged view of the vicinity of a seal member 15 portion in a closed state of the valve 10 when the pressure chamber 6 is in a high pressure state.

[Explanation of symbols]

2b End wall inner surface 9 Communication hole 10 Valve 11 Valve body portion 12a Support body 12aa Support body end portion 15 Seal member 15b Seal member end portion 17 Slit 17a Small slit 17b Large slit 18 Escape

Claims (2)

[Claims] 1. A valve seat having a communication hole which is a fluid passage,
A valve having a columnar support and an annular seal member fitted to the outer periphery of the support and elastically deformed by contacting the valve seat to close the communication hole, the seal comprising: The member has a relief on the inner peripheral side of the end of the seal member on the valve seat side, the support extends into the communication hole and is slidable in the communication hole, and the outer periphery of the support Is formed with a slit extending in the axial direction of the support at the end of the support on the valve seat side, and the slit is formed on the outer periphery of the support so that the seal member is maximized in the valve seat direction. A valve which is provided from a portion distant from the contact portion between the extended seal member and the valve seat toward the end portion of the support body. 2. The valve according to claim 1, wherein the slit comprises a small slit from the sealing member side and a large slit continuous with the small slit.