WO2023181851A1

WO2023181851A1 - Pressure regulator valve

Info

Publication number: WO2023181851A1
Application number: PCT/JP2023/008065
Authority: WO
Inventors: 晃裕大野; 聡志中村
Original assignee: 愛三工業株式会社
Priority date: 2022-03-23
Filing date: 2023-03-03
Publication date: 2023-09-28
Also published as: JP2023140566A

Abstract

A pressure regulator (1) has a fluid pressure chamber (11) communicating with a fluid passage (111), and a valve member (30) which separates from a valve seat (13) in a state in which a fluid pressure in the fluid pressure chamber (11) is higher than a set pressure. A valve body (31) of the valve member (30) comprises: a flat portion (311) forming an annular flat surface facing the valve seat (13); a recessed portion (312) located on a radially inner side of the flat portion (311), and formed by denting a valve seat (13) side of the valve body (31); and a slope portion (313) connecting a radially inner-side edge of the flat portion (311) and a radially outer-side edge of the recessed portion (312). A seal member (32) comprises: a dent portion (322) dented corresponding to the recessed portion (312); an annular protruding portion (321) formed to protrude toward the valve seat (13), at a location corresponding to the boundary between the flat portion (311) and the slope portion (313); and a connection portion (323) corresponding to the slope portion (313), and connecting a radially inner-side edge of the protruding portion (321) and a radially outer-side edge of the dent portion (322) with a slope surface.

Description

pressure regulating valve

The present disclosure relates to a pressure regulating valve.

US Pat. No. 9,328,836 discloses that a rubber seal member C is attached to the surface of the valve body A that contacts the valve seat B, as shown in FIGS. 7 and 8, in order to improve the sealing performance in the closed state. A pressure regulating valve is disclosed. In this pressure regulating valve, an annular protrusion D is provided on the surface of the valve body A facing the valve seat B in order to increase the surface pressure of the seal member C at the annular portion where the valve body A contacts the valve seat B when the valve is closed. is forming. In this portion, the seal member C is shaped to wrap around the protrusion D.

In the above pressure regulating valve, the compression pressure applied by the protrusion D to the sealing member C in the portion surrounding the protrusion D becomes particularly high when the valve is closed. Therefore, as shown in FIG. 9, internal stress locally increases at the bent portion C1 of the sealing member C corresponding to the outer peripheral edge D1 of the projection D. As a result, the bent portion C1 of the seal member C may be damaged due to long-term use of the pressure regulating valve. Therefore, there is a need for improved pressure regulating valves.

In one aspect of the present disclosure, the pressure regulating valve includes a fluid pressure chamber that is in communication with the fluid passage and is filled with fluid from the fluid passage, and a chamber that is adjacent to the fluid pressure chamber, A discharge chamber communicated with a discharge passage for flowing fluid discharged from the chamber, and a boundary portion that partitions the fluid pressure chamber and the discharge chamber so as to receive the fluid pressure of the fluid pressure chamber, and the fluid pressure When the pressure in the chamber is lower than the set pressure, the valve is in the closed position to cut off the flow of fluid from the fluid pressure chamber to the discharge chamber, and when the pressure in the fluid pressure chamber is higher than the set pressure, the valve is in the closed position to block the flow of fluid from the fluid pressure chamber to the discharge chamber. A valve body is arranged in an annular manner along the boundary between the fluid pressure chamber and the discharge chamber, and the valve body is in the open position for discharging fluid into the chamber, and the valve body is in the closed position. The valve seat includes a valve seat that provides the valve body with a fluid blocking function by abutting against the valve seat, and a spring that biases the valve body from the valve open position toward the valve closed position. The valve body is fixed to a valve body forming a base portion of the valve body and to the valve seat side of the valve body, and is pressed between the valve body and the valve seat in the valve closing position to generate elasticity. a sealing member that is deformed to improve the fluid blocking performance of the valve body, and the valve body includes a flat part forming an annular plane facing the valve seat in a movement direction accompanying opening and closing of the valve body; , a recess located on the inner diameter side of the flat part and formed by recessing the valve seat side in the moving direction, and an inclined surface connecting the inner diameter side edge of the flat part and the outer diameter side edge of the recess. the sealing member includes a recessed portion corresponding to the recessed portion of the valve body, and an annular boundary portion between the flat portion and the sloped portion of the valve body. An annular protrusion formed to protrude toward the valve seat and correspond to the valve seat at a corresponding position in the movement direction; and an inner diameter side end edge of the protrusion corresponding to the inclined part of the valve body. and a connecting portion that connects the outer diameter side edge portion of the recessed portion with an inclined surface.

According to the above aspect, when the valve body is closed, the protrusion of the sealing member comes into contact with the valve seat, is compressed, and is elastically deformed. Thereby, the surface pressure necessary for the seal member to maintain its fluid blocking performance is ensured. At this time, the elastic deformation of the protrusion is distributed to the inner diameter side and the outer diameter side of the valve body along the flat part and the inclined part of the valve body. Therefore, in the seal member, local increase in internal stress is suppressed. Therefore, durability deterioration of the sealing member due to repeated opening and closing of the valve body is suppressed.

1 is a longitudinal sectional view showing a pressure regulator according to Embodiment 1. FIG. FIG. 2 is an enlarged sectional view of the valve body of the pressure regulator in FIG. 1. FIG. FIG. 3 is an enlarged view of section III in FIG. 2, showing the valve body and valve seat in an open state. FIG. 3 is an enlarged view of section III in FIG. 2 in a valve closed state. 3 is an enlarged view of the first comparative example, and corresponds to section III in FIG. 2. FIG. 3 is an enlarged view of a second comparative example, and corresponds to section III in FIG. 2. FIG. FIG. 2 is a longitudinal sectional view showing a conventional pressure regulating valve. 8 is an enlarged view of the valve body of FIG. 7 in an open state, together with the valve seat; FIG. FIG. 9 is an enlarged view of section IX in FIG. 8 in a valve closed state.

<Overall configuration of pressure regulator>
FIG. 1 shows a pressure regulator 1 corresponding to Embodiment 1 of a pressure regulating valve. The pressure regulator 1 is configured to adjust the pressure of fuel supplied to an engine such as a gasoline engine or a diesel engine to a set pressure. In FIG. 1, the lower side of the drawing will be described as one side, and the upper side will be described as the other side. The same applies to other figures.

The pressure regulator 1 shown in FIG. 1 has a housing 10 made of metal and having a generally cylindrical shape. The housing 10 accommodates a valve body 30, a spring 40, etc. therein. One end of the housing 10 has a smaller diameter than the other end, and has a fluid passage 111 formed therein. The diameter of the housing 10 increases stepwise from one end to the other end. A portion whose diameter is increased by one step from the fluid passage 111 is defined as the fluid pressure chamber 11 . A portion whose diameter is increased by two steps from the fluid passage 111 is defined as a discharge chamber 12 . On the other side of the discharge chamber 12, the diameter is gradually increased to form an open end 14. Therefore, the fluid pressure chamber 11 constitutes one chamber filled with fuel (equivalent to fluid) in the fluid passage 111. Further, the discharge chamber 12 constitutes one room adjacent to the fluid pressure chamber 11.

The side surface of the discharge chamber 12 at the stepped portion forming the boundary between the fluid pressure chamber 11 and the discharge chamber 12 is an annular valve seat 13 . A substantially disk-shaped valve body 30 is in contact with the valve seat 13 . The valve body 30 is disposed within the discharge chamber 12 and is movable within the discharge chamber 12 in opposing directions between one side and the other side. The valve seat 13 that the valve body 30 abuts has an annular shape. The other side of the valve body 30 is fixed to the other end of the discharge chamber 12 by a cover member 20 via a compression coil spring (hereinafter referred to as spring) 40 . Note that the cover member 20 is press-fitted and fixed to the inner wall of the discharge chamber 12. The spring 40 is supported so that the inner diameter side of the coil fits into the ring-shaped spring guide 33 of the valve body 30 and the convex-shaped spring guide 21 of the cover member 20. Therefore, the valve body 30 comes into contact with the valve seat 13 due to the biasing force of the spring 40, thereby blocking the flow of fuel from the fluid pressure chamber 11 to the discharge chamber 12. That is, when the valve body 30 comes into contact with the valve seat 13, the inside of the housing 10 is partitioned into a fluid pressure chamber 11 and a discharge chamber 12.

The fluid passage 111 communicates with a fuel passage (not shown) that supplies fuel discharged from a fuel pump (not shown) to an engine (not shown). An O-ring 50 is fitted around the outer periphery of the housing 10 forming the fluid passage 111. The O-ring 50 functions to prevent fuel leakage when the fluid passage 111 is communicated with the fuel passage. A plurality of through holes are bored in the peripheral wall surface of the housing 10 forming the discharge chamber 12, and the through holes are used as a discharge passage 121. The discharge passage 121 communicates with a fuel tank (not shown) so as to return fuel to the fuel tank (not shown).

When the fuel pressure (corresponding to fluid pressure) in the fluid pressure chamber 11 applied through the fluid passage 111 becomes higher than the set pressure, the pressure regulator 1 enters an open state in which the valve body 30 is separated from the valve seat 13. Therefore, the fuel in the fluid pressure chamber 11 flows into the discharge chamber 12 and is discharged from the discharge passage 121 into the fuel tank. In this way, when the fuel in the fluid pressure chamber 11 is discharged from the discharge passage 121 through the discharge chamber 12 and the fuel pressure in the fluid pressure chamber 11 becomes lower than the set pressure, the pressure regulator 1 causes the valve body 30 to move due to the biasing force of the spring 40. The valve is in a closed state in contact with the valve seat 13. In the valve closed state, the flow of fuel from the fluid pressure chamber 11 to the discharge chamber 12 is blocked. In this way, the fuel pressure in the fluid passage 111 and the fuel passage connected to the fluid pressure chamber 11 is adjusted to the set pressure. In this specification, the position of the valve seat 13 in the valve open state is referred to as the "valve open position", and the position of the valve seat 13 in the valve closed state is referred to as the "valve closed position".

<Configuration of valve body>
FIG. 2 shows the valve body 30 in an enlarged manner. Further, FIG. 3 shows a further enlarged view of part III in FIG. The valve body 30 includes a resin valve body 31 forming a base portion of the valve body 30, and a rubber seal member 32 fixed to the valve seat 13 side of the valve body 31. The valve body 31 covers an area surrounded by the valve seat 13 including the annular valve seat 13 when the valve body 30 is in the closed position. Further, the seal member 32 is pressed between the valve body 31 and the valve seat 13 in the closed position and is elastically deformed, thereby improving the fluid blocking performance when the valve body 30 is in the closed position. A through hole 314 penetrating from one side to the other side is bored in the center of the disc of the valve body 31. A fitting portion 324 formed protruding from the center of the disk of the sealing member 32 is fitted into the through hole 314 . Actually, with the valve body 31 set in the mold, the rubber forming the seal member 32 is poured and baked, so that the fitting part 324 fits into the through hole 314 and the seal member 32 is attached to the valve body 31. It will be worn.

The valve body 31 includes a flat part 311 formed in an annular shape on the outer periphery of the surface facing the valve seat 13 , a recess 312 surrounded by the flat part 311 , and an inner edge of the flat part 311 and a concave part 312 . An inclined portion 313 connecting the outer diameter side edge portion with an inclined surface is provided. The plane portion 311 forms a plane that faces the valve seat 13 in the direction of movement of the valve body 30 as it opens and closes. The recessed portion 312 is formed by recessing the valve seat 13 side in the direction of movement of the valve body 30 as it opens and closes. The boundary between the flat portion 311 and the inclined portion 313 is formed by a curved surface.

The sealing member 32 includes a recess 322 that corresponds to the recess 312 of the valve body 31, an annular protrusion 321 that protrudes toward the valve seat 13, and an inner diameter end edge of the protrusion 321. and a connecting portion 323 that connects the outer diameter side edge portion of the recessed portion 322 with an inclined surface. The protruding portion 321 corresponds to the annular boundary between the flat portion 311 and the inclined portion 313 of the valve body 31 in the direction of movement of the valve body 31 . In FIG. 3, the boundary between the flat portion 311 and the inclined portion 313 of the valve body 31 is indicated by a chain line. The connecting portion 323 is formed of an inclined surface corresponding to the inclined portion 313 of the valve body 31.

The annular boundary between the recessed part 322 and the connecting part 323 of the seal member 32 is located closer to the outer diameter of the valve body 30 than the annular boundary between the recessed part 312 and the inclined part 313 of the valve body 31. Furthermore, the recessed portion 322 of the seal member 32 and the flat portion 311 of the valve body 31 are substantially equal in distance from each other to the valve seat 13 when the valve body 30 is in the open position. In FIG. 3, the facing distance between the flat portion 311 and the valve seat 13 is shown as "L1", and the facing distance between the recessed part 322 and the valve seat 13 is shown as "L2".

<Actions and effects of Embodiment 1>
When the fuel pressure in the fluid pressure chamber 11 becomes lower than the set pressure and the valve body 30 is brought to the closed position by the biasing force of the spring 40, the protrusion 321 of the seal member 32 comes into contact with the valve seat 13. Therefore, the protrusion 321 is compressed by the biasing force of the spring 40 so that the amount of protrusion toward the valve seat 13 is reduced. As a result of this compression, the seal member 32 is elastically deformed as shown in FIG. That is, the protruding portion 321 is bulged toward the outer diameter side and the inner diameter side of the valve body 30, respectively, as shown by the arrows. Further, the recessed portion 322 of the seal member 32 is bulged toward the valve seat 13 side. Thereby, the sealing member 32 is provided with the surface pressure necessary to maintain fluid blocking performance. At this time, the elastic deformation of the protrusion 321 is distributed to the inner diameter side and the outer diameter side of the valve body 30 along the flat part 311 and the inclined part 313 of the valve body 31. Therefore, in the seal member 32, local increase in internal stress is suppressed. Further, the force that causes the outer diameter side edge portion of the seal member 32 to peel off from the flat surface portion 311 of the valve body 31, which is caused by the protrusion portion 321 being deformed toward the outer diameter side of the valve body 30, is suppressed. Therefore, durability deterioration of the seal member 32 due to repeated opening and closing of the valve body 30 is suppressed.

<Comparison between Embodiment 1 and Comparative Example>
FIG. 5 shows a first comparative example in which the protruding portion 321 of the sealing member 32 is positioned on the inner diameter side of the valve body 30 from the boundary between the flat portion 311 and the inclined portion 313 of the valve body 31 (indicated by a dashed line in FIG. 5). The case where it is formed is shown below. In this case, when the protruding part 321 of the sealing member 32 comes into contact with the valve seat 13 and is compressed and deformed, the protruding part 321 elastically moves toward the inner diameter side of the valve body 30 along the inclined surface of the inclined part 313 of the valve body 31. transformed. Therefore, elastic deformation of the protrusion 321 occurs with a relatively small compression pressure, making it impossible to obtain sufficient surface pressure to perform the fuel cutoff function. In addition, the outer diameter side edge portion of the seal member 32 is subjected to a force that causes it to peel off from the flat surface portion 311 of the valve body 31, and as the valve body 30 is repeatedly opened and closed, the durability of the seal member 32 is accelerated.

FIG. 6 shows a second comparative example in which the protruding portion 321 of the seal member 32 is connected to the outer diameter of the valve body 30 from the boundary between the flat portion 311 and the inclined portion 313 of the valve body 31 (indicated by the dashed line in FIG. 6). The case where it is formed on the side is shown. In this case, when the protruding part 321 of the sealing member 32 comes into contact with the valve seat 13 and is compressed and deformed, the elastic deformation of the protruding part 321 is applied to the outer diameter side of the valve body 30 along the flat part 311 of the valve body 31. It is carried out towards On the other hand, elastic deformation of the protruding portion 321 toward the inner diameter side of the valve body 30 is hardly performed. Therefore, the internal stress of the seal member 32 near the boundary between the flat part 311 and the inclined part 313 of the valve body 31 increases locally, and durability deterioration of the seal member 32 is accelerated as the valve body 30 is repeatedly opened and closed. .

<Other embodiments>
Although the content of the present disclosure has been described above with respect to specific embodiments, various changes can be made without departing from the gist thereof. For example, in the embodiment described above, an example of a pressure regulator that regulates fuel pressure is shown as a pressure regulating valve, but the content of the present disclosure may be applied to a valve that regulates the pressure of other fluids. Further, in the above embodiment, the through hole 314 is formed in the valve body 31, but the valve body 31 may not have the through hole 314.

In the above embodiment, the boundary between the flat portion 311 and the inclined portion 313 of the valve body 31 is formed by a curved surface, but the boundary portion may be joined by a flat surface. Further, the boundary between the recessed portion 322 and the connecting portion 323 of the seal member 32 is not limited to being disposed closer to the outer diameter side of the valve body 30 than the boundary between the recessed portion 312 and the inclined portion 313 of the valve body 31. Further, the recessed portion 322 of the seal member 32 and the flat portion 311 of the valve body 31 do not have to have substantially the same distance from each other with respect to the valve seat 13 when the valve body 30 is in the open position.

Furthermore, the contents of the present disclosure can be implemented in various ways. In a first aspect, the pressure regulating valve includes a fluid pressure chamber communicating with the fluid passage and forming a chamber filled with fluid from the fluid passage, and a chamber adjacent to the fluid pressure chamber; a discharge chamber communicated with a discharge passage to flow fluid discharged from the fluid pressure chamber; and a discharge chamber arranged to receive fluid pressure of the fluid pressure chamber at a boundary portion separating the fluid pressure chamber and the discharge chamber; When the pressure is lower than the set pressure, the valve is in the closed position to cut off the flow of fluid from the fluid pressure chamber to the discharge chamber, and when the pressure of the fluid pressure chamber is higher than the set pressure, the valve is closed from the fluid pressure chamber to the discharge chamber. a valve body that is in an open position for discharging fluid to the valve body, and a valve body that is arranged in an annular manner along the boundary part at a boundary part that partitions the fluid pressure chamber and the discharge chamber, and the valve body is in the valve closed position. The valve seat includes a valve seat that causes the valve body to have a fluid blocking function by abutting against the valve seat, and a spring that biases the valve body from the valve open position toward the valve closed position. The valve body is fixed to a valve body forming a base portion of the valve body and to the valve seat side of the valve body, and is pressed between the valve body and the valve seat in the valve closing position to generate elasticity. a sealing member that is deformed to improve the fluid blocking performance of the valve body, and the valve body includes a flat part forming an annular plane facing the valve seat in a movement direction accompanying opening and closing of the valve body; , a recess located on the inner diameter side of the flat part and formed by recessing the valve seat side in the moving direction, and an inclined surface connecting the inner diameter side edge of the flat part and the outer diameter side edge of the recess. the sealing member includes a recessed portion corresponding to the recessed portion of the valve body, and an annular boundary portion between the flat portion and the sloped portion of the valve body. An annular protrusion formed to protrude toward the valve seat and correspond to the valve seat at a corresponding position in the movement direction; and an inner diameter side end edge of the protrusion corresponding to the inclined part of the valve body. and a connecting portion that connects the outer diameter side edge portion of the recessed portion with an inclined surface.

According to the first aspect, when the valve body is closed, the protruding portion of the sealing member comes into contact with the valve seat, is compressed, and is elastically deformed. Thereby, the surface pressure necessary for the seal member to maintain its fluid blocking performance is ensured. At this time, the elastic deformation of the protrusion is distributed to the inner diameter side and the outer diameter side of the valve body along the flat part and the inclined part of the valve body. Therefore, in the seal member, local increase in internal stress is suppressed. Therefore, durability deterioration of the sealing member due to repeated opening and closing of the valve body is suppressed.

In a second aspect, in the pressure regulating valve of the first aspect described above, the boundary between the flat part and the inclined part of the valve body is formed by a curved surface.

According to the second aspect, the protruding portion of the seal member is pressed toward the valve seat at the boundary between the flat portion and the inclined portion of the valve body. At this time, since the boundary part is formed by a curved surface, local stress concentration in the sealing member due to the shape of the boundary part can be suppressed compared to a case where the boundary part is a joint between two flat surfaces.

In a third aspect, in the pressure regulating valve according to the first aspect or the second aspect, an annular boundary between the recessed part and the connecting part of the sealing member is connected to the recessed part of the valve body. The recessed portion of the sealing member and the flat portion of the valve body are arranged on the outer diameter side of the annular boundary with the inclined portion, and the distance between the recessed portion of the sealing member and the flat portion of the valve body and the valve seat in the valve opening position of the valve body is They are considered to be virtually equivalent to each other.

According to the third aspect, the boundary between the recessed portion of the seal member and the connecting portion is on the outer diameter side of the valve body than the boundary between the recessed portion and the inclined portion of the valve body, and the recessed portion of the seal member and the valve The flat portion of the main body has substantially the same distance from the valve seat. As a result, when the protrusion of the seal member comes into contact with the valve seat and is elastically deformed, it is suppressed from deforming biased toward the inner diameter of the valve body, and the deformation of the protrusion is caused to occur on the inner and outer diameter sides of the valve body. It is well balanced. Therefore, the protrusion of the seal member is prevented from deforming biased toward the inner diameter side of the valve body, and the outer diameter edge of the seal member is prevented from receiving a force that causes it to peel off from the flat surface of the valve body, thereby increasing the durability of the seal member. can be increased.

In the third aspect, the facing distance between the recessed portion of the sealing member and the valve seat may be made equal to the flat portion of the valve body at least on the side closer to the connecting portion. The setting of the above-mentioned distance at a portion of the recessed portion remote from the connecting portion does not affect the elastic deformation of the protruding portion, and does not have to be the same.

In a fourth aspect, in the pressure regulating valve of the third aspect described above, in the valve closing position of the valve body, the protruding portion of the sealing member is configured such that the amount of protrusion toward the valve seat side is small. The seal member is compressed and elastically deformed, and is elastically deformed so as to bulge toward both inner and outer diameter sides of the annular protrusion, and the recessed portion of the seal member bulges toward the valve seat. It is elastically deformed.

According to the fourth aspect, as the protruding part of the seal member is compressed and deformed in the valve closed position, the protruding part bulges out to both the inner and outer sides of the valve body and is elastically deformed, and the recessed part It bulges toward the seat side and is elastically deformed. Therefore, it is possible to prevent the outer diameter side edge portion of the seal member from receiving a force that causes it to peel off from the flat surface portion of the valve body, thereby increasing the durability of the seal member.

Claims

a fluid pressure chamber communicating with the fluid passageway and forming a chamber filled with fluid from the fluid passageway;
a discharge chamber adjacent to the fluid pressure chamber and communicated with a discharge passage for flowing fluid discharged from the fluid pressure chamber;
The fluid pressure chamber is arranged so as to receive the fluid pressure of the fluid pressure chamber at a boundary portion that partitions the fluid pressure chamber and the discharge chamber, and when the pressure of the fluid pressure chamber is lower than a set pressure, the pressure from the fluid pressure chamber to the discharge chamber is a valve body that is in a closed position to block the flow of fluid, and in an open position to discharge fluid from the fluid pressure chamber to the discharge chamber when the pressure in the fluid pressure chamber is higher than a set pressure;
Disposed annularly along the boundary between the fluid pressure chamber and the discharge chamber, the valve body has a fluid blocking function when the valve body comes into contact with the valve at the valve closing position. The valve seat and
a spring that urges the valve body from the valve open position to the valve closed position,
The valve body is
a valve body forming a base portion of the valve body;
a sealing member fixed to the valve seat side of the valve body, and elastically deformed by being pressed between the valve body and the valve seat in the valve closed position, improving the fluid blocking performance of the valve body; Equipped with
The valve body is
a flat portion forming an annular flat surface facing the valve seat in the direction of movement as the valve body opens and closes;
a recessed portion located on the inner diameter side of the flat portion and recessed on the valve seat side in the moving direction;
an inclined part that is an inclined surface connecting an inner diameter side edge part of the flat part and an outer diameter side edge part of the recessed part,
The sealing member is
a recessed portion corresponding to the recessed portion of the valve body;
an annular protrusion formed to protrude toward the valve seat and correspond to the valve seat at a position corresponding in the movement direction to an annular boundary between the flat part and the inclined part of the valve body;
A pressure regulating valve, comprising: a connecting part that corresponds to the inclined part of the valve body and connects the inner diameter side edge of the protruding part and the outer diameter side edge of the recessed part with an inclined surface.
In claim 1,
A boundary part between the flat part and the inclined part of the valve body is formed by a curved surface. The pressure regulating valve.
In claim 1 or 2,
The annular boundary between the recessed part and the connecting part of the sealing member is arranged on the outer diameter side of the annular boundary between the recessed part and the inclined part of the valve body,
The recessed portion of the sealing member and the flat portion of the valve body have substantially the same opposing distance from the valve seat at the valve opening position of the valve body.
In claim 3,
In the closed position of the valve body,
The protrusion of the sealing member is compressed and elastically deformed so that the amount of protrusion toward the valve seat is reduced, and the protrusion is bulged toward both the inner and outer diameter sides of the annular protrusion. elastically deformed,
The recessed portion of the sealing member is elastically deformed so as to bulge toward the valve seat.