JP2019173588A - Valve unit fixing structure - Google Patents

Abstract

To provide an inexpensive valve unit fixing structure which can easily fix a valve unit without the necessity of unitization in advance.SOLUTION: A valve unit fixing structure comprises a discharge valve unit 10 and a main body part 3 fixed thereto. The discharge valve unit 10 comprises a holder part 29 for accommodating a spring member 28 for energizing a valve body 26 to a valve seat part 25. The valve seat part 25 comprises a valve seat abutment part 25a abutting on the main body part 3 in a reference direction S, and a valve seat load receiving part 32 for receiving a load in the reference direction S which is imparted to the valve seat part 25 by the holder part 29. The holder part 29 comprises a holder abutment part 33 abutting on the valve seat load receiving part 32, and a holder load receiving part 34 for receiving a load in the reference direction S imparted to the holder part 29 by a deformation fixing part 35 in which the main body part 3 is elastically deformed and arranged.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a valve unit fixing structure for fixing a valve unit to a main body.

  Conventionally, a valve unit fixing structure including a valve unit and a main body portion to which the valve unit is fixed is known (for example, see Patent Documents 1 and 2). The main body portion includes a main body flow path that is provided therein and through which a fluid flows, and a bottom portion that is in communication with the main body flow path. The valve unit includes a valve seat portion having a valve seat, a valve body that contacts the valve seat and closes the main body flow path, a spring member that biases the valve body toward the valve seat portion, and a holder portion that houses the spring member With.

  In the valve unit fixing structure of Patent Document 1, for the discharge valve unit, the valve seat part, the valve body, the spring member and the holder part are assembled outside the main body part, and the valve seat part and the holder part are laser welded, After unitization, it is structured to be press-fitted into the recess of the main body and fixed.

  Also in the valve unit fixing structure of Patent Document 2, it is considered that a part of the valve units are similarly assembled by unitizing the valve seat portion and the holder into the concave portion.

JP 2011-80391 A JP 2004-138062 A

  However, according to the valve unit fixing structure of Patent Documents 1 and 2, since the unit is unitized by welding or the like prior to fixing to the concave portion of the main body, troubles such as welding, or deformation after welding Processes such as volume control are required. These processes prevent the supply of an inexpensive valve unit fixing structure.

  In general, the valve seat portion is heat treated to increase its hardness, and the holder portion is formed of a low hardness material so that it can be easily molded. For this reason, since welding of a valve seat part and a holder part becomes welding of a dissimilar material, the difficulty of welding is also high.

  An object of the present invention is to provide an inexpensive valve unit fixing structure capable of easily fixing a valve unit without needing to be unitized in advance in view of the problems of the prior art.

The valve unit fixing structure according to the first invention is
A valve unit and a main body to which the valve unit is fixed;
The body part is
A main body flow path that is provided inside the main body and through which a fluid flows;
A recess extending through the body channel and extending in a reference direction;
The valve unit is
A valve seat portion having a valve seat;
A valve body that contacts the valve seat and closes the main body flow path;
A spring member for urging the valve body toward the valve seat portion;
A holder portion for accommodating the spring member,
At least a portion is inserted in the reference direction with respect to the recess and fixed to the main body,
In the valve unit fixing structure, the valve seat portion includes a valve seat abutting portion that abuts the main body portion in the reference direction.
The valve seat portion includes a valve seat load receiving portion that receives the load in the reference direction that the holder portion abuts and the holder portion applies to the valve seat portion,
The holder part is
A holder contact portion that contacts the valve seat load receiving portion;
A holder load receiving portion that receives the load in the reference direction that the main body portion gives to the holder portion;
The load in the reference direction that the main body portion applies to the holder portion is provided by a deformation fixing portion that is provided by plastic deformation of the main body portion.

  According to the first invention, the load in the reference direction applied to the holder portion by the deformation fixing portion is supported by the bottom portion of the recess through the holder load receiving portion, the holder abutting portion, the valve seat load receiving portion, and the valve seat abutting portion. Is done. That is, the shape of the valve unit inserted into the recess is maintained and fixed to the main body by the deformation fixing portion and the recess of the main body.

  For this reason, the valve seat part, the valve body, the spring member, and the holder part are inserted into the concave part of the main body part without being previously unitized using welding or the like, and only a deformation fixing part is provided (the caulking process is performed). The unitization of the valve unit and the fixing to the main body can be performed simultaneously.

  Even if the valve seat is fixed to the main body after the valve seat, valve body, spring member, and holder are unitized in advance, the shape of the valve unit after being attached to the main body is modified and fixed. Since the valve seat part, the valve body, the spring member, and the holder part are unitized in advance, the fixing structure can be simplified.

  Therefore, it is possible to provide an inexpensive valve unit fixing structure that can easily fix the valve unit to the main body with less man-hours. Moreover, since it is not necessary to press-fit the valve unit into the concave portion of the main body, high dimensional accuracy for managing the tightening allowance necessary for press-fitting is not required.

The valve unit fixing structure according to the second invention is the first invention,
The valve seat portion includes a substantially cylindrical valve seat inner wall surface that is connected to the main body flow path and forms at least a part of an internal flow path through which the fluid flows.
The recess is
A recess inner wall surface extending in parallel with the reference direction;
A flow path opening which is a portion where the main body flow path opens in the recess;
A main body contact surface extending from the flow path opening to an end edge of the recess inner wall on the flow path opening side,
The valve seat contact portion is in contact with the main body contact surface,
The range in which the valve seat contact portion is projected onto a projection plane orthogonal to the reference direction is included in the range in which the main body contact surface is projected onto the projection plane,
The valve seat contact portion is formed in an annular shape surrounding the entire circumference of the flow path opening.

  According to the second invention, the load applied to the holder portion by the deformation fixing portion in order to fix the valve unit to the main body portion concentrates on the valve seat abutting portion formed in an annular shape. For this reason, even if the surface roughness of the valve seat contact portion and the surface of the main body contact surface in contact with the surface is large, minute irregularities on both surfaces are crushed. It is possible to maintain a good sealing property between the two.

The valve unit fixing structure according to the third invention is the first or second invention,
The holder part includes a substantially cylindrical inner peripheral surface,
The valve seat portion includes a radial load receiving portion that contacts the inner peripheral surface and receives a load applied to the valve seat portion in a direction orthogonal to the reference direction with respect to the valve seat portion. .

  According to the third aspect of the present invention, the radial load generated by the fixing (clamping) of the valve unit by the deformation fixing portion and applied to the holder load receiving portion by the deformation fixing portion is received by the radial load receiving portion of the valve seat portion. be able to. Thereby, since it becomes possible to form a holder part thinly, size reduction and weight reduction of a valve unit fixing structure can be achieved.

The valve unit fixing structure according to a fourth aspect of the invention is any one of the first to third aspects of the invention,
At least a part of the range in which the valve seat abutment portion is projected onto the projection plane orthogonal to the reference direction is included in the range in which the valve seat load receiving portion is projected onto the projection plane,
The valve seat surface of the valve seat portion that contacts the valve body and the main body contact surface of the main body portion that contacts the valve seat contact portion are both formed as surfaces on a plane that is substantially orthogonal to the reference direction. It is characterized by being.

  According to the fourth invention, since the load applied to the valve seat load receiving portion is linearly transmitted to the valve seat abutting portion, bending stress is hardly generated inside the valve seat portion. Thereby, the precision of the valve seat surface of a valve seat part can be maintained, and the flatness of the valve body contact | abutted to a valve seat surface can be maintained.

It is sectional drawing which shows the principal part of the high pressure fuel pump which concerns on one Embodiment of this invention. It is sectional drawing of the discharge valve unit in the high pressure fuel pump of FIG. It is a figure which shows a mode that the large diameter recessed part in the high pressure fuel pump of FIG. 1 was seen from the opening part side. It is sectional drawing which shows the modification of the discharge valve unit in the high pressure fuel pump of FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a main part of a high-pressure fuel pump in a fuel supply system for a direct injection engine according to an embodiment of the present invention. This high-pressure fuel pump boosts the pressure of the fuel sent from the fuel tank using the rotational power of the engine cam and supplies it to the injector.

  As shown in FIG. 1, the high-pressure fuel pump 1 includes a main body 3 having a pressurizing chamber 2. The pressurizing chamber 2 is used for sucking the fuel sent from the fuel tank and increasing the pressure to discharge the fuel. The fuel is supplied to the pressurizing chamber 2 from a suction pipe 4 connected to a low-pressure fuel pump of the fuel tank through a damper chamber 6 in which a pulsation damper 5 is disposed and a suction port 7.

  The main body 3 includes a high pressure passage 8 through which fuel discharged from the pressurizing chamber 2 passes, and a main body flow path 9 adjacent to the pressurizing chamber 2 and interposed between the pressurizing chamber 2 and the high pressure passage 8. Is provided. A discharge valve unit 10 that discharges the fuel pressurized in the pressurizing chamber 2 to the high-pressure passage 8 side is provided on the downstream side of the main body flow path 9.

  In addition, a relief valve 11 is provided between the high-pressure passage 8 and the damper chamber 6, which is a lower pressure space than the high-pressure passage 8, to release the fuel whose pressure has become too high from the high-pressure passage 8 side to the damper chamber 6 side. Provided. Although not shown, an intake valve (spill valve) that controls intake of fuel into the pressurizing chamber 2 is provided upstream of the intake port 7.

  The main body portion 3 is provided with a large-diameter recess 12 that opens to the outer surface of the main body portion 3 and forms a part of the high-pressure passage 8. The discharge valve unit 10 and the relief valve 11 are inserted from the inside surrounded by the inner wall surface 12 a of the large-diameter recess 12 and are fixed to the main body 3.

  On the opening side of the large-diameter concave portion 12, a high-pressure connecting portion 13 that constitutes a part of the high-pressure passage 8 together with the large-diameter concave portion 12 is coupled. A portion of the high-pressure passage 8 that communicates with the injector is connected to the side of the high-pressure connecting portion 13 opposite to the large-diameter recess 12.

  The lower surface of the pressurizing chamber 2 is defined by the distal end surface of the plunger 14. The plunger 14 is reciprocated to repeatedly perform a cycle of sucking, compressing, and discharging fuel into the pressurizing chamber 2. This reciprocation is performed by the urging force of the spring 15 and a cam that is driven against the urging force by the power of the engine crankshaft or the like.

  The main body 3 is provided with a relief passage 16 that leads from the high-pressure passage 8 to the damper chamber 6. The relief passage 16 has a passage portion 18 that is parallel to the central axis 17 (see FIG. 2) of the discharge valve unit 10 and that has one end opened to the bottom surface 12 b of the large-diameter recess 12.

  The relief valve 11 includes a valve body 19, a valve seat member 20 that is press-fitted into the passage portion 18 and cooperates with the valve body 19, and is inserted into the passage portion 18 and compressed by the press-fitting of the valve seat member 20. The member 20 includes a spring member 21 that biases the valve body 19.

  FIG. 2 shows a cross section of the discharge valve unit 10. As shown in FIG. 2, the main body flow path 9 of the main body 3 is open to the pressurizing chamber 2 on the upstream side. A small-diameter recess 23 that extends in the reference direction S and opens in the bottom surface 12 b of the large-diameter recess 12 is provided on the large-diameter recess 12 side of the main body channel 9. At the bottom of the small diameter recess 23, the downstream side of the main body channel 9 is open.

  The discharge valve unit 10 energizes the valve seat 25 having the valve seat 25e, the valve body 26 that contacts the valve seat 25e to close the main body flow path 9, and the valve body 26 contacts the valve seat 25e. And a holder portion 29 that accommodates the spring member 28. The internal space of the holder portion 29 communicates with the internal space of the large-diameter concave portion 12. The discharge valve unit 10 is at least partially inserted in the reference direction S with respect to the small-diameter recess 23 and fixed to the main body 3.

  The valve seat portion 25 connects the upstream large outer diameter portion 30, the downstream small outer diameter portion 31 having a smaller outer diameter, and the large outer diameter portion 30 and the small outer diameter portion 31 in a step shape. And a valve seat contact portion 25a that contacts the main body portion 3 in the reference direction S. The valve seat abutting portion 25a is a portion that is in direct contact with the main body portion 3, and a portion around the portion is not included in the valve seat abutting portion 25a.

  The valve seat portion 25 includes a substantially cylindrical valve seat inner wall surface 25c that is connected to the main body flow path 9 and forms at least a part of an internal flow path 25b through which a fluid flows.

  The valve seat load receiving portion 32 receives a load applied to the valve seat portion 25 in a reference direction S parallel to the central axis 17 of the discharge valve unit 10 by contacting the holder portion 29. The valve seat load receiving portion 32 is a portion that is in direct contact with the holder portion 29, and a portion around the portion is not included in the valve seat load receiving portion 32.

  The holder portion 29 includes a holder contact portion 33 that contacts the valve seat load receiving portion 32 and a holder load receiving portion 34 that receives a load that the main body portion 3 applies to the holder portion 29 in the reference direction S.

  The load that the main body portion 3 applies to the holder portion 29 in the reference direction S is given by a deformation fixing portion 35 that is provided by plastic deformation of the main body portion 3. That is, the discharge valve unit 10 inserted into the small-diameter recess 23 of the main body 3 is fixed to the main body 3 by the deformation fixing portion 35.

  The small-diameter recess 23 includes a recess inner wall surface 23 a extending in parallel with the reference direction S, a channel opening 22 where the main body channel 9 is open at the bottom of the small-diameter recess 23, and a channel opening 22. To a bottom end side edge of the inner wall surface 23a of the recess. The valve seat abutting portion 25 a is formed in an annular shape that abuts the main body abutting surface 23 b and surrounds the entire circumference of the flow path opening 22.

  The main body contact surface 23b includes a surface of a portion that is in direct contact with the valve seat contact portion 25a and a surface of a peripheral portion that constitutes one surface continuously with the surface. Therefore, the range in which the valve seat contact portion 25a is projected onto the projection plane orthogonal to the reference direction S is included in the range in which the main body contact surface 23b is projected onto the projection plane.

  The holder portion 29 includes a substantially cylindrical inner peripheral surface 29a. The valve seat portion 25 includes a radial load receiving portion 25d that abuts against the inner peripheral surface 29a and receives a load that the inner peripheral surface 29a applies to the valve seat portion 25 in a direction orthogonal to the reference direction S.

  At least a part of the range in which the valve seat contact portion 25a is projected onto the projection plane perpendicular to the reference direction S is included in the range in which the valve seat load receiving portion 32 is projected onto the projection plane. The valve seat surface that contacts the valve body 26 and the main body contact surface 23 b of the valve seat portion 25 are both formed as surfaces on a plane that is substantially orthogonal to the reference direction S.

  FIG. 3 shows a state in which the large-diameter recess 12 is viewed in the reference direction S from the opening side. As shown in FIG. 3, the deformation fixing portion 35 has an equal interval at a plurality of, for example, two locations on the circumference centering on the central axis 17 of the discharge valve unit 10 on the bottom surface 12 b of the large-diameter recess 12. To be formed.

  The non-deformation part 36, which is a part other than the deformation fixing part 35 on the circumference of the main body part 3 (a part between the adjacent deformation fixing parts 35), each center C <b> 1 of the discharge valve unit 10 and the relief valve 11, It intersects with a valve arrangement direction surface 37 that passes through C2 and is parallel to the extending direction of the main body flow path 9.

  That is, the non-deformation portion 36 is located between the centers C1 and C2 of both the discharge valve unit 10 and the relief valve 11 when viewed in the extending direction, that is, on the relief valve 11 side of the discharge valve unit 10. Crosses 37. The center C1 is the center of the portion where the valve body 26 and the valve seat 25e of the discharge valve unit 10 are in contact. The center C2 is the center of the portion where the valve body 19 of the relief valve 11 and the valve seat member 20 are in contact.

  The plurality of deformation fixing portions 35 are formed so as to exhibit plane symmetry with the valve arrangement direction surface 37 as a symmetry plane. Therefore, the non-deformation portion 36 intersects the valve arrangement direction surface 37 on the opposite side to the direction from the center C1 of the discharge valve unit 10 toward the relief valve 11, that is, on the opposite side to the relief valve 11 of the discharge valve unit 10. .

  The discharge valve unit 10 and the relief valve 11 are incorporated into the main body 3 as follows. That is, with respect to the discharge valve unit 10, first, the valve seat portion 25, the valve body 26, the spring member 28, and the holder portion 29 arranged in a mutual positional relationship as shown in FIG. The seat 25 is inserted until the valve seat contact portion 25a contacts the main body contact surface 23b of the small diameter recess 23.

  Next, the deformation fixing portion 35 is formed by a cylindrical jig J having an inner diameter approximately equal to the outer diameter of the holder portion 29 and having a tip corresponding to the deformation fixing portion 35.

  That is, the jig J is disposed at a circumferential position corresponding to the deformation fixing portion 35 in FIG. 3 on the outer periphery of the holder portion 29. Then, the peripheral portion of the small-diameter recess 23 on the bottom surface 12b of the large-diameter recess 12 is pressed in the direction of the central axis 17 by the front end surface of the jig J and is plastically deformed. Thereby, the deformation | transformation fixing | fixed part 35 which has a cross-sectional shape and arrangement | positioning like FIG.2 and FIG.3 is formed, and the assembly of the discharge valve unit 10 is completed.

  When the deformation fixing portion 35 is formed, plastic deformation is not performed on the valve arrangement direction surface 37 and in the vicinity thereof, so that the occurrence of distortion on the main body portion 3 is kept to a minimum. For this reason, the formation of the deformation fixing portion 35 does not significantly affect the passage portion 18 of the relief passage 16.

  For the relief valve 11, first, the spring member 21 is inserted into the passage portion 18 of the relief passage 16. Next, the valve seat member 20 is press-fitted into the passage portion 18 in a state where the valve body 19 is disposed between the spring member 21 and the valve seat member 20. At this time, the press-fitting amount is adjusted to be a predetermined valve opening pressure. Thereby, the assembly of the relief valve 11 is completed.

  This valve opening pressure is such that when a high pressure that cannot be controlled by the suction valve provided on the upstream side of the pressurizing chamber 2 is generated in the high pressure passage 8 for some reason, the pressure can be opened without any problem. Set to

  In the high-pressure fuel pump 1 in which the discharge valve unit 10 and the relief valve 11 are incorporated in this way, when the plunger 14 is reciprocated according to the driving of the engine, the intake valve is opened when the plunger 14 is lowered. The fuel flows into the pressurizing chamber 2. Further, when the plunger 14 is raised, the suction valve is closed and the fuel in the pressurizing chamber 2 is compressed.

  Thereby, since the inside of the pressurizing chamber 2 becomes high pressure, the discharge valve unit 10 is opened and high pressure fuel is discharged into the high pressure passage 8. The discharged fuel is injected from the injector through the high-pressure passage 8. During this time, if the pressure in the high pressure passage 8 becomes excessive for some reason, the relief valve 11 is opened, and the high pressure fuel in the high pressure passage 8 is released into the damper chamber 6 through the relief passage 16.

  The relief valve 11 functions as a safety device that mechanically releases the pressure of the high-pressure passage 8 when the pressure of the high-pressure passage 8 becomes excessive in this way. Therefore, the valve opening pressure needs to be accurately maintained. is there. In this regard, when the discharge valve unit 10 is assembled as described above, the influence of the relief valve 11 hardly affects the relief passage 16 despite the fact that the main body 3 is plastically deformed. Retained.

  As described above, according to the present embodiment, the valve seat portion 25, the valve body 26, the spring member 28, and the holder portion 29 are inserted into the small-diameter recessed portion 23 of the main body portion 3 without being previously unitized, and the deformation fixing portion The unitization of the discharge valve unit 10 and the fixing to the main body 3 can be performed at the same time only by providing 35 (performing the caulking process).

  Therefore, since the discharge valve unit 10 can be fixed to the main body 3 with less man-hours, an inexpensive valve unit fixing structure can be provided. Further, since it is not necessary to press-fit the discharge valve unit 10 into the small-diameter concave portion 23 of the main body 3, high dimensional accuracy for managing the tightening margin necessary for press-fitting is not required.

  Further, since the load for fixing the discharge valve unit 10 is concentrated on the valve seat contact portion 25a formed in an annular shape, the surface of the valve seat contact portion 25a and the main body contact surface 23b in contact with the surface. Even when the surface roughness of the surface is large, minute irregularities on the surface are crushed. Thereby, the sealing performance of the valve seat part 25 and the main-body part 3 can be kept favorable.

  Further, since the deformation fixing portion 35 generated by fixing (caulking fixing) by the deformation fixing portion 35 can receive the radial load applied to the holder load receiving portion 34 by the valve seat portion 25, the holder portion 29 is formed thin. It becomes possible to do. Thereby, size reduction and weight reduction of a valve unit fixing structure can be achieved.

  In addition, since a part of the range in which the valve seat contact portion 25a is projected onto the projection plane orthogonal to the reference direction S is included in the range in which the valve seat load receiving portion 32 is projected onto the projection plane, the valve seat load The load applied to the receiving portion 32 is transmitted linearly to the valve seat abutting portion 25a. The main body contact surface 23b and the valve seat surface of the valve seat portion 25 are both formed as surfaces on a plane substantially orthogonal to the reference direction S.

  For this reason, it is difficult for bending stress to be generated inside the valve seat portion 25, and the valve seat surface of the valve seat portion 25 maintains a state substantially orthogonal to the reference direction S, so that the valve element that contacts the valve seat surface 26 flatness can be maintained.

  In addition, this invention is not limited to said embodiment. For example, the present invention can be applied to valve units other than the discharge valve unit.

  Further, as shown in FIG. 4, the main body contact surface 23 b and the valve seat contact portion 25 a are not necessarily perpendicular to the reference direction S and may not be parallel to each other. Also in this case, the range in which the valve seat contact portion 25a is projected onto the projection plane orthogonal to the reference direction S is included in the range in which the main body contact surface 23b is projected onto the projection plane. The sealing property between the main body 3 can be kept good.

  Further, in this case, the valve seat abutting portion 25a comes into contact with the valve seat abutting portion 25a in a narrower region because the cross-sectional shape has a curvature and abuts against the main body abutting surface 23b. Therefore, in this case, the sealing performance between the valve seat portion 25 and the main body portion 3 can be kept better.

  DESCRIPTION OF SYMBOLS 1 ... High pressure fuel pump, 2 ... Pressurization chamber, 3 ... Main part, 4 ... Suction pipe, 5 ... Pulsation damper, 6 ... Damper chamber, 7 ... Suction port, 8 ... High pressure passage, 9 ... Main body flow path, 10 ... Discharge valve unit, 11 ... relief valve, 12 ... large diameter recess, 12a ... inner wall surface, 12b ... bottom surface, 13 ... high pressure connection, 14 ... plunger, 15 ... spring, 16 ... relief passage, 17 ... central axis, 18 ... A passage part, 19 ... Valve body, 20 ... Valve seat member, 21 ... Spring member, 22 ... Flow path opening, 23 ... Small diameter recessed part, 23a ... Inner wall surface of recessed part, 23b ... Body contact surface, 25 ... Valve seat part, 25a ... Valve seat contact part, 25b ... Internal flow path, 25c ... Valve seat inner wall surface, 25d ... Radial load receiving part, 25e ... Valve seat, 26 ... Valve body, 28 ... Spring member, 29 ... Holder part, 29a ... inner peripheral surface, 30 ... large outer diameter part, 31 ... small outer diameter part, 32 ... valve seat load receiving part, 33 ... hol It abutments 34 ... holder load receiving section, 35 ... deformable fixing section, 36 ... non-deformable portion, 37 ... valve orientation plane, J ... jig, S ... reference direction.

Claims (4)

A valve unit and a main body to which the valve unit is fixed;
The body part is
A main body flow path that is provided inside the main body and through which a fluid flows;
A recess extending through the body channel and extending in a reference direction;
The valve unit is
A valve seat portion having a valve seat;
A valve body that contacts the valve seat and closes the main body flow path;
A spring member for urging the valve body toward the valve seat portion;
A holder portion for accommodating the spring member,
At least a portion is inserted in the reference direction with respect to the recess and fixed to the main body,
In the valve unit fixing structure, the valve seat portion includes a valve seat abutting portion that abuts the main body portion in the reference direction.
The valve seat portion includes a valve seat load receiving portion that receives the load in the reference direction that the holder portion abuts and the holder portion applies to the valve seat portion,
The holder part is
A holder contact portion that contacts the valve seat load receiving portion;
A holder load receiving portion that receives the load in the reference direction that the main body portion gives to the holder portion;
The valve unit fixing structure according to claim 1, wherein the load in the reference direction applied to the holder part by the main body part is provided by a deformation fixing part provided by plastic deformation of the main body part. The valve seat portion includes a substantially cylindrical valve seat inner wall surface that is connected to the main body flow path and forms at least a part of an internal flow path through which the fluid flows.
The recess is
A recess inner wall surface extending in parallel with the reference direction;
A flow path opening which is a portion where the main body flow path opens in the recess;
A main body contact surface extending from the flow path opening to an end edge of the recess inner wall on the flow path opening side,
The valve seat contact portion is in contact with the main body contact surface,
The range in which the valve seat contact portion is projected onto a projection plane orthogonal to the reference direction is included in the range in which the main body contact surface is projected onto the projection plane,
The valve unit fixing structure according to claim 1, wherein the valve seat abutting portion is formed in an annular shape surrounding the entire circumference of the flow path opening. The holder part includes a substantially cylindrical inner peripheral surface,
The valve seat portion includes a radial load receiving portion that contacts the inner peripheral surface and receives a load applied to the valve seat portion in a direction orthogonal to the reference direction with respect to the valve seat portion. The valve unit fixing structure according to claim 1 or 2. At least a part of the range in which the valve seat abutment portion is projected onto the projection plane orthogonal to the reference direction is included in the range in which the valve seat load receiving portion is projected onto the projection plane,
The valve seat surface of the valve seat portion that contacts the valve body and the main body contact surface of the main body portion that contacts the valve seat contact portion are both formed as surfaces on a plane that is substantially orthogonal to the reference direction. The valve unit fixing structure according to any one of claims 1 to 3, wherein the valve unit fixing structure is provided.