CN112503203A

CN112503203A - Control valve

Info

Publication number: CN112503203A
Application number: CN201910870052.7A
Authority: CN
Inventors: 不公告发明人
Original assignee: Zhejiang Sanhua Climate and Appliance Controls Group Co Ltd
Current assignee: Zhejiang Sanhua Commercial Refrigeration Co ltd
Priority date: 2019-09-16
Filing date: 2019-09-16
Publication date: 2021-03-16
Anticipated expiration: 2039-09-16
Also published as: CN112503203B

Abstract

According to the control valve provided by the invention, when the differential pressure force between the fluid inlet end and the fluid outlet end is smaller than the set force, the first sealing part is abutted against the valve core, when the differential pressure force between the fluid inlet end and the fluid outlet end is larger than the set force, the valve core can overcome the elastic force of the elastic piece to move towards the fluid outlet end, and the fluid at the fluid inlet end flows into the valve core cavity through the gap between the first sealing part and the valve core, so that the pressure relief purpose is achieved. Compared with the mode that the ball valve and the one-way valve are connected in parallel in the background art, the control valve is compact in structure.

Description

Control valve

Technical Field

The invention relates to the technical field of fluid control, in particular to a control valve.

Background

Fig. 13 is a schematic diagram illustrating a parallel structure of a ball valve and a check valve in the prior art. At present, in a refrigeration system, when a ball valve 01 is closed, a liquid refrigerant retained in a pipeline part 03 at the inlet end of the ball valve 01 increases the pressure along with the rise of the ambient temperature, so that the risk of damage to parts in the system due to overhigh pressure is reduced, the common ball valve 01 and a check valve 02 are respectively arranged on different pipelines in a parallel connection mode, and the purpose of pressure relief is achieved through the check valve 02. This structure is complicated.

In view of the above, how to optimize the structure of the valve provides an improvement to those skilled in the art.

Disclosure of Invention

The invention aims to provide a control valve, which comprises a valve body, a valve seat, a valve core, a valve rod, a first sealing part and a second sealing part, wherein the valve body is fixedly connected with the valve seat, the valve core is arranged in a valve cavity of the control valve, the valve core comprises a valve core cavity, the valve core cavity can be communicated with a fluid inlet end and a fluid outlet end, the valve rod can drive the valve core to rotate in the circumferential direction,

the first sealing part is positioned on one side of the valve core close to the fluid inlet end, the second sealing part is positioned on one side of the valve core close to the fluid outlet end, the second sealing part is abutted against the valve core, the control valve further comprises an elastic piece, one end of the elastic piece is abutted against the valve body or the valve seat, the other end of the elastic piece is abutted against the second sealing part, when the pressure difference force between the fluid inlet end and the fluid outlet end is smaller than a set force in the valve closing state of the control valve, the first sealing part is abutted against the valve core, the valve core cavity is communicated with the fluid outlet end of the control valve, the valve core cavity is not communicated with the fluid inlet end of the control valve, and when the pressure difference force between the fluid inlet end and the fluid outlet end is larger than the set force, the valve core can move towards the fluid outlet end by overcoming the elastic force of the elastic piece, fluid at the fluid inlet end flows into the valve core cavity through a gap between the first sealing part and the valve core.

According to the control valve provided by the embodiment, when the differential pressure force between the fluid inlet end and the fluid outlet end is smaller than the set force, the first sealing part abuts against the valve core, when the differential pressure force between the fluid inlet end and the fluid outlet end is larger than the set force, the valve core can overcome the elastic force of the elastic part to move towards the fluid outlet end, fluid at the fluid inlet end flows into the valve core cavity through a gap between the first sealing part and the valve core, the pressure relief purpose is achieved, and compared with the situation that a ball valve and a one-way valve are arranged on different pipelines in the background art, the control valve is compact in structure.

Drawings

FIG. 1: the invention provides a valve opening state diagram of a control valve;

FIG. 2 a: the invention provides a first valve closing state diagram of a control valve;

FIG. 2 b: the invention provides a second valve closing state diagram of the control valve;

FIG. 3: i in FIG. 2₁A partially enlarged schematic view of (a);

FIG. 4: FIG. 2 is a schematic view of a first seal member;

FIG. 5: i in FIG. 2₂A partially enlarged schematic view of (a);

FIG. 6: another structure schematic diagram of the second sealing part;

FIG. 7: FIG. 2 is a schematic illustration of the valve stem configuration;

FIG. 8 a: FIG. 2 is a schematic cross-sectional view of the cartridge;

FIG. 8 b: the structure of the valve core in FIG. 2 is shown schematically as I;

FIG. 8 c: the structure of the valve core in FIG. 2 is schematically illustrated as II;

FIG. 9: FIG. 2 is a schematic view of the support member;

FIG. 10: the invention provides a valve closing state diagram of another control valve;

FIG. 11: FIG. 10 is a schematic illustration of the valve stem configuration;

FIG. 12 a: FIG. 10 is a schematic cross-sectional view of the cartridge;

FIG. 12 b: the structure of the valve core in FIG. 10 is schematic;

fig. 13 is a schematic diagram illustrating a parallel structure of a ball valve and a check valve in the prior art.

In fig. 1 to 12 b:

1-valve body, 10-fluid inlet end, 100-valve cavity, 101-gap and 11-through hole;

12-mounting hole, 121-hole wall, 13-second step part and 14-first groove;

2-valve seat, 20-fluid outlet end, 21-second step, 211-first step wall;

22-first annular groove, 3/3' -spool, 30-spool chamber;

31/31 '-first groove, 311/311' -first longitudinal side;

312/312' -second longitudinal side, 313-third step;

32-second slot portion, 321-fifth longitudinal side, 322-sixth longitudinal side;

33-communication channel, 34-bypass flow path, 4/4 '-valve rod, 41/41' -shaft part;

411/411 '-third longitudinal side, 412/412' -fourth longitudinal side;

413-flange portion, 5-first sealing member, 51-first gasket, 52-boss portion;

6-a second sealing member, 61/61' -a second gasket;

611-an outer peripheral wall of the second gasket, 62/62' -a second annular groove;

the outer peripheral wall of the 63-connector, 631-connector;

8-bonnet, 9-support, 91-mating section, 911-seventh longitudinal side;

912-eighth longitudinal side, 92-base, 921-peripheral wall of base;

a-a first connecting pipe and B-a second connecting pipe.

Detailed Description

The core of the embodiment is to provide a control valve, in a valve closing state, when the differential pressure force between a fluid inlet end and a fluid outlet end is smaller than a set force, a first sealing part is abutted to a valve core, when the differential pressure force between the fluid inlet end and the fluid outlet end is larger than the set force, the valve core can overcome the elastic force of an elastic part to move towards the fluid outlet end, fluid at the fluid inlet end flows into a valve core cavity through a gap between the first sealing part and the valve core to achieve the purpose of pressure relief, and compared with the prior art that a ball valve and a one-way valve are respectively arranged on different pipelines, the control valve is compact in structure.

In order that those skilled in the art will better understand the disclosure, the invention will be described in further detail with reference to the accompanying drawings and specific embodiments.

It should be noted that the terms "upper" and "lower" as used herein are defined in fig. 1-12 b as they relate to the position of the components in the drawings and the positions of the components relative to each other, and are only used for the sake of clarity and convenience in the technical solution. It is to be understood that the directional terms used herein are not intended to limit the scope of the claims.

FIG. 1 is a diagram showing an open state of a control valve according to the present invention; FIG. 2a is a first valve closing state diagram of the control valve according to the present invention; FIG. 2b is a second valve closing state diagram of the control valve of the present invention; FIG. 3 is the drawing I in FIG. 2₁A partially enlarged schematic view of (a);FIG. 4 is a schematic view of the first seal member of FIG. 2; FIG. 5 is the drawing I in FIG. 2₂A partially enlarged schematic view of (a); FIG. 6 is a schematic view of another second seal member; FIG. 7 is a schematic illustration of the valve stem of FIG. 2; FIG. 8a is a schematic cross-sectional view of the valve cartridge of FIG. 2; FIG. 8b is a first schematic structural view of the valve cartridge of FIG. 2; FIG. 8c is a second schematic structural view of the valve cartridge of FIG. 2; fig. 9 is a schematic structural view of the supporting member in fig. 2.

As shown in fig. 1, the control valve of the present embodiment includes a valve body 1, a valve seat 2, a valve element 3, a valve stem 4, a first sealing member 5, a second sealing member 6, a bonnet 8, a first connection pipe a, and a second connection pipe B. The valve body 1 is made of metal materials through forging and comprises an inner cavity, a through hole 11 and a fluid inlet end 10, one end of the valve body 1 is fixedly welded with the second connecting pipe B, and the other end of the valve body 1 is fixedly connected with the valve seat 2 through threads or fixedly welded. The valve body 1 is screwed with the bonnet 8. The valve seat 2 comprises a fluid outlet end 20, and the valve seat 2 is fixedly welded with the first connecting pipe A. The valve rod 4 is roughly columnar and penetrates through the through hole 11 of the valve body 1, the upper end of the valve rod 4 extends out of the valve body 1, and the lower end of the valve rod 4 extends into the inner cavity of the valve body 1 and is connected with the valve core 3 through a key groove. The valve body 3 is substantially spherical and is provided in a valve chamber 100 of the control valve, the valve body 3 includes a valve body chamber 30, the valve body 3 is located between a first seal member 5 and a second seal member 6, and the second seal member 6 is always in contact with the valve body 3. Specifically, the lower end of the valve rod 4 has a shaft portion 41, the shaft portion 41 extends into the first groove portion 31 of the valve plug 3, the valve rod 4 can drive the valve plug 3 to rotate circumferentially, and the valve plug 3 rotates to enable the valve plug cavity 30 to communicate with the fluid inlet port 10 and the fluid outlet port 20. In the valve-closed state of the control valve, the spool chamber 30 is communicated with the fluid outlet end 20, and the spool chamber 30 is not communicated with the fluid inlet end 10.

In this embodiment, as shown in fig. 1, fig. 2a, and fig. 2b, the first sealing member 5 is located on one side of the valve core 3 close to the fluid inlet end 10, that is, the first sealing member 5 is located on one side of the valve body 1, and the first sealing member 5 is fixedly connected or in limited connection with the valve body 1; the second sealing member 6 is located on the side of the spool 3 close to the fluid outlet port, i.e., the second sealing member 6 is provided on the side of the valve seat 2. The control valve further comprises an elastic member 7, which elastic member 7 is embodied as a spring, one end of the elastic member 7 abutting the valve seat 2 and the other end abutting the second sealing member 6. In the control valve closed state, when the differential pressure force between the fluid inlet end 10 and the fluid outlet end 20 is smaller than the set force, as shown in fig. 2a, the first sealing member 5 abuts against the valve core 3; when the pressure difference between the fluid inlet end 10 and the fluid outlet end 20 is greater than the set force, as shown in fig. 2b, the valve plug 3 can move toward the fluid outlet end 20 against the elastic force of the elastic member 7, so that the first sealing member 5 and the valve plug 3 form a gap 101, and the fluid at the fluid inlet end 10 can flow into the valve plug cavity 30 of the valve plug 3 through the gap 101. Under the valve closing state of the control valve, because the valve core cavity 30 is communicated with the fluid outlet end 20, fluid flows out from the fluid outlet end 20 through the valve core cavity 30, and the purpose of pressure relief is achieved.

Of course, the present embodiment is only illustrated based on the drawings, and it is understood that the fluid inlet port may be disposed on the valve seat 2, and correspondingly, the fluid outlet port may be disposed on the valve body 1, such that the first sealing member 5 is disposed on one side of the valve seat 2, the first sealing member 5 is fixedly or limitedly connected to the valve seat 2, and the second sealing member 6 is disposed on one side of the valve body 1. At this time, one end of the elastic member 7 abuts on the valve body 1, and the other end abuts on the second seal member 6.

In this embodiment, in a valve closing state of the control valve, when a differential pressure between the fluid inlet end 10 and the fluid outlet end 20 is smaller than a set force, the first sealing member 5 abuts against the valve core 3, and when the differential pressure between the fluid inlet end 10 and the fluid outlet end 20 is larger than the set force, the valve core 3 can move toward the fluid outlet end 20 by overcoming an elastic force of the elastic member 7, and a fluid at the fluid inlet end 10 flows into the valve core cavity 30 through a gap between the first sealing member 5 and the valve core 3, so as to achieve a pressure relief purpose. Compared with the prior art in which the ball valve and the one-way valve are respectively arranged on different pipelines, the control valve has a compact structure.

Specifically, as shown in fig. 2a, 2b, 3, and 4, the first seal member 5 is a first seal gasket 51, the first seal gasket 51 has a substantially annular shape, and a projection 52 is provided on an outer peripheral wall of the first seal gasket 51. The valve body 1 comprises a first step part 13, the step wall of the first step part 13 is provided with a groove part 14, and the first step part 13 is arranged in the groove part 14 to limit the first sealing gasket 51 to be separated from the valve body 1. Of course, the first gasket 51 may be press-fitted to the step wall of the first step portion 13 by interference fit, or the first gasket 51 may be fixed to the first step portion 13 by glue bonding, as long as the object of the present embodiment is achieved.

As shown in fig. 8a and 8b, the valve body chamber 30 of the valve body 3 of the present embodiment has a substantially T-shaped configuration, and includes a communication passage 33 and a bypass passage 34, the communication passage 33 passes through the valve body 3 through the center of the valve body 3, and the bypass passage 34 communicates between the outer surface of the valve body 3 and the communication passage 33. In the control valve open state, the fluid inlet port 10 and the fluid outlet port 20 communicate through the communication passage 33, and in the control valve closed state, the communication passage 33 communicates with the fluid outlet port 20 through the bypass flow path 34.

Further, as shown in fig. 2a, 2b, and 5, the valve seat 2 includes a second step portion 21 having a step surface facing the valve element 3, and the second step portion 21 is provided with a first annular groove 22, and the first annular groove 22 opens toward the valve element 3. The second sealing member 6 is a second sealing gasket 61, the second sealing gasket 61 is substantially annular and includes a second annular groove 62, the second annular groove 62 opens toward the fluid outlet end 20, one end of the elastic member 7 is located in the first annular groove 22, and the other end of the elastic member 7 is located in the second annular groove 62. In the valve closing state of the control valve, when the pressure difference between the fluid at the fluid inlet end 10 and the fluid at the fluid outlet end 20 is greater than the set pressure, the spool 3 can move toward the fluid outlet end 20 against the elastic force of the elastic member 7, and since the second gasket 61 abuts against the spool 3, in the process, the outer peripheral wall of the second gasket 61 is in sliding fit with the step wall 211 of the second step portion 21, and the spool 3 compresses the elastic member 7 through the second gasket 61.

Of course, as shown in fig. 6 in combination with fig. 5, it is also possible to design the second sealing member 6 ' to include a second seal gasket 61 ' and a connecting member 63, the second seal gasket 61 ' being substantially annular. In the present embodiment, one end of the connecting member 63 adjacent to the spool 3 abuts the second seal gasket 61 ', and the other end of the connecting member 63 includes a second annular groove 62', the second annular groove 62 'opening toward the fluid outlet port 20, one end of the elastic member 7 is located in the first annular groove 22, and the other end of the elastic member 7 is located in the second annular groove 62'. When the pressure difference between the fluid inlet 10 and the fluid outlet 20 is greater than the predetermined pressure in the closed state of the control valve, the valve body 3 can move toward the fluid outlet 20 against the elastic force of the elastic member 7, and since the second gasket 61 ' abuts against the valve body 3, the connecting member 63 abuts against the second gasket 61 ', and during this process, the outer peripheral wall of the connecting member 63 slidably engages with the step wall 211 of the second step portion 21, and the valve body 3 compresses the elastic member 7 via the second sealing member 6 '.

When the fluid pressure at the fluid inlet end 10 is released to the fluid outlet end 20, the elastic element 7 is restored, and the second sealing member 6 and the valve element 3 are pushed to move toward the fluid inlet end 10 by the elastic force of the elastic element 7 until the valve element 3 abuts against the first sealing member 5.

Further, as shown in fig. 7, 8a, and 8b, the first groove portion 31 of the valve body 3 has a substantially rectangular horizontal projection, and the side wall thereof includes a first longitudinal side surface 311 and a second longitudinal side surface 312 which are substantially parallel to each other. The shaft portion 41 of the valve stem 4 comprises a third longitudinal side 411 and a fourth longitudinal side 412 which are substantially parallel, the first longitudinal side 311 being in abutment or clearance fit with the third longitudinal side 411 and the second longitudinal side 312 being in abutment or clearance fit with the fourth longitudinal side 412. In the closed state of the control valve, when the force of the fluid pressure difference between the fluid inlet end 10 and the fluid outlet end 20 is greater than the set force, the spool 3 can slide relative to the valve stem 4 toward the fluid outlet end 20.

As shown in fig. 2b, 8c and 9, in the present embodiment, the control valve further includes a support member 9, and the inner bottom wall of the valve body 1 is provided with a mounting hole 12, and the mounting hole 12 is a circular counter bore and has a circular cross section. The spool 3 includes a second groove portion 32, and the second groove portion 32 and the first groove portion 31 are provided symmetrically with respect to the communication passage 33. As shown in fig. 8a, the first groove portion 31 is located at the upper end of the valve body 3, and the second groove portion 32 is located at the lower end of the valve body 3. The support 9 comprises a base 92 and a mating section 91, the base 92 extending at least partially into the mounting hole 12, and the mating section 91 extending at least partially into the second slot portion 32. Specifically, the side walls of the second slot portion 32 include a fifth longitudinal side 321 and a sixth longitudinal side 322; the mating segment 91 has a generally rectangular horizontal projection, and its side walls include generally parallel seventh and eighth

longitudinal sides

911 and 912. The fifth longitudinal side 321 fits snugly or loosely with the seventh longitudinal side 911 and the sixth longitudinal side 322 fits snugly or loosely with the eighth longitudinal side 912. The base 92 of the support 9 is circular in cross-section, and the peripheral wall of the base 92 is rotatably fitted to the hole wall 121 of the mounting hole 12. In the closed state of the control valve, when the pressure difference between the fluid inlet end 10 and the fluid outlet end 20 is greater than a set force, the valve core 3 can slide relative to the valve stem 4 and the support 9 toward the fluid outlet end 20.

Of course, in order to increase the smoothness of the sliding movement of the valve body 3 relative to the valve stem 4 and the support member 9 toward the fluid outlet end 20 or the fluid inlet end 10, it is further preferable that the groove bottom of the first groove portion 31 is formed in a flat bottom structure, and the groove bottom of the second groove portion 32 is formed in a flat bottom structure.

With such an arrangement, when the differential pressure between the fluid inlet end 10 and the fluid outlet end 20 of the control valve is greater than a predetermined pressure, the valve element 3 slides toward the fluid outlet end 20 against the elastic force of the elastic member 7, thereby achieving the purpose of pressure relief. The control valve of the embodiment integrates the functions of the one-way valve in the background technology, and has a compact structure; compared with the background art, the method and the device have the advantages that welding points connected with the pipeline piece are reduced, and the leakage risk of the control valve can be reduced.

FIG. 10 is a close valve state diagram of an alternative control valve according to the present invention; FIG. 11 is a schematic illustration of the valve stem of FIG. 10; FIG. 12a is a cross-sectional schematic view of the valve cartridge of FIG. 10; fig. 12b is a schematic structural view of the valve cartridge of fig. 10.

The difference between the present embodiment and the above embodiments lies in the structure and connection matching manner of the valve rod and the valve core. As shown in fig. 10, 11, 12a and 12 b. In the present embodiment, the first groove portion 31 ' of the spool 3 ' includes the third step portion 313 whose step surface faces the spool chamber 30, and the side wall of the first groove portion 31 ' includes the first longitudinal side surface 311 ' and the second longitudinal side surface 312 ' which are substantially parallel. The side wall of the shaft portion 41 ' comprises a third 411 ' and a fourth 412 ' substantially parallel longitudinal side, the shaft portion 41 ' of the valve stem 4 ' comprises a flange portion 413 extending radially outwards from the third 411 ' and the fourth 412 ' longitudinal side, the first 311 ' and the third 411 ' longitudinal sides being in a snug or clearance fit, and the second 312 ' and the fourth 412 ' longitudinal sides being in a snug or clearance fit. The upper end surface of the flange portion 413 abuts against the step surface of the third step portion 313 to restrict the axial separation of the spool 3 'from the stem 4'. In the closed state of the control valve, when the pressure difference between the fluid inlet end 10 and the fluid outlet end 20 is greater than the set force, the valve core 3 'can slide relative to the valve rod 4' toward the fluid outlet end 20. This embodiment has the same technical effects as those of the above-described embodiment, and the description thereof will not be repeated.

It should be noted that the "setting force" in the above embodiments is designed according to the specification parameters required by the control valve in the system, and the specific influencing factors include: the elastic force of the elastic member 7, the frictional force of the outer peripheral wall of the second packing 61 slidably fitted with the step wall 211 of the second step portion 21, or the frictional force of the outer peripheral wall of the connecting member 63 slidably fitted with the step wall 211 of the second step portion 21, the resistance of the fluid inside the control valve, the viscosity of the fluid, and the like.

The principles and embodiments of the present invention are explained herein using specific examples, which are presented only to assist in understanding the method and its core concepts. It should be noted that, for those skilled in the art, it is possible to make various improvements and modifications to the present invention without departing from the principle of the present invention, and those improvements and modifications also fall within the scope of the claims of the present invention.

Claims

1. A control valve comprises a valve body, a valve seat, a valve core, a valve rod, a first sealing part and a second sealing part, wherein the valve body is fixedly connected with the valve seat, the valve core is arranged in a valve cavity of the control valve, the valve core comprises a valve core cavity, the valve core cavity can be communicated with a fluid inlet end and a fluid outlet end, the valve rod can drive the valve core to rotate circumferentially,

the first sealing part is positioned on one side of the valve core close to the fluid inlet end, the second sealing part is positioned on one side of the valve core close to the fluid outlet end, the second sealing part is abutted against the valve core, the control valve further comprises an elastic piece, one end of the elastic piece is abutted against the valve body or the valve seat, the other end of the elastic piece is abutted against the second sealing part, when the pressure difference force between the fluid inlet end and the fluid outlet end is smaller than a set force, the first sealing part is abutted against the valve core, the valve core cavity is communicated with the fluid outlet end of the control valve, the valve core cavity is not communicated with the fluid inlet end of the control valve, and when the pressure difference force between the fluid inlet end and the fluid outlet end is larger than the set force, the valve core can overcome the elastic force of the elastic piece to move towards the fluid outlet end, fluid at the fluid inlet end flows into the valve core cavity through a gap between the first sealing part and the valve core.

2. The control valve of claim 1, wherein the fluid inlet port is disposed on the valve body, the fluid outlet port is disposed on the valve seat, the first sealing member is fixedly or captively connected to the valve body, one end of the elastic member abuts against the valve seat, and the other end of the elastic member abuts against the second sealing member.

3. The control valve of claim 1, wherein the spool includes a first slot portion, wherein a sidewall of the first slot portion includes first and second substantially parallel longitudinal sides, wherein the stem includes a shaft portion engaged with the first slot portion, wherein a sidewall of the shaft portion includes third and fourth substantially parallel longitudinal sides, wherein the first longitudinal side is engaged or clearance-fitted with the third longitudinal side, and wherein the second longitudinal side is engaged or clearance-fitted with the fourth longitudinal side, wherein the spool is slidable relative to the stem toward the fluid outlet port when a differential pressure force between the fluid inlet port and the fluid outlet port is greater than the set force in the control valve-off state.

4. The control valve of claim 3, further comprising a support member, wherein the valve body defines a mounting hole, wherein the support member includes a mating segment and a base, wherein the mating segment extends at least partially into the second slot portion of the valve cartridge, wherein the base extends at least partially into the mounting hole, wherein the base has a circular cross-section, wherein the mounting hole has a circular cross-section, and wherein the base is rotatable relative to the valve body.

5. The control valve of claim 4, wherein the side walls of the second slot portion include fifth and sixth substantially parallel longitudinal sides, the side walls of the upper portion of the support member include seventh and eighth substantially parallel longitudinal sides, the fifth longitudinal side being in abutting or clearance fit with the seventh longitudinal side, and the sixth longitudinal side being in abutting or clearance fit with the eighth longitudinal side; when the pressure difference force between the fluid inlet end and the fluid outlet end is larger than the set force in the valve closing state of the control valve, the valve core can slide towards the fluid outlet end relative to the support piece.

6. The control valve of claim 1, wherein the first slot portion includes a third step portion having a stepped surface facing the spool chamber, wherein a sidewall of the first slot portion includes first and second substantially parallel longitudinal sides, wherein the valve stem includes a shaft portion engaged with the first slot portion, wherein a sidewall of the shaft portion includes third and fourth substantially parallel longitudinal sides, wherein the shaft portion includes a flange portion extending radially outward from the third and fourth longitudinal sides, wherein the first longitudinal side is engaged or clearance-fitted with the third longitudinal side, wherein the second longitudinal side is engaged or clearance-fitted with the fourth longitudinal side, wherein an upper end surface of the flange portion is engaged with the stepped surface of the third step portion to restrict axial disengagement of the valve stem from the spool, and wherein the control valve is in a valve-off state, the spool is slidable relative to the stem toward the fluid outlet port.

7. The control valve according to any one of claims 1 to 6, wherein the first seal member comprises a first seal pad, the first seal pad is substantially annular, an outer peripheral wall of the first seal pad is provided with a projection, the valve body comprises a first stepped portion, a step wall of the first stepped portion is provided with a groove portion, and the projection is disposed in the groove portion.

8. The control valve according to any one of claims 1 to 6, wherein the valve seat includes a second step portion facing the valve element with a step surface, the second step portion includes a first annular groove opening toward the valve element, the second seal member includes a second seal gasket having a substantially annular shape, the second seal gasket includes a second annular groove opening toward the fluid outlet port, one end of the elastic member is located in the first annular groove, the other end of the elastic member is located in the second annular groove, and an outer peripheral wall of the second seal gasket is slidably fitted with a step wall of the second step portion.

9. The control valve according to any one of claims 1 to 6, wherein the valve seat includes a second step portion having a step surface facing the valve element, the second step portion includes a first annular groove having an opening facing the valve element, the second seal member includes a connecting member and a second seal, the second seal is substantially annular, one end of the connecting member near the valve element abuts the second seal, the other end of the connecting member includes a second annular groove having an opening facing the fluid outlet port, one end of the elastic member is located in the first annular groove, the other end of the elastic member is located in the second annular groove, and the outer peripheral wall of the connecting member is slidably fitted to the step wall of the second step portion.