CN113677919A

CN113677919A - Flow control valve and method of assembling the same

Info

Publication number: CN113677919A
Application number: CN202080008945.1A
Authority: CN
Inventors: 菱谷康平
Original assignee: Fujikoki Corp
Current assignee: Fujikoki Corp
Priority date: 2019-02-21
Filing date: 2020-01-27
Publication date: 2021-11-19
Anticipated expiration: 2040-01-27
Also published as: CN113677919B; JP6910683B2; WO2020170720A1; JPWO2020170720A1

Abstract

Provided are a flow rate control valve and an assembling method thereof, which can effectively reduce the differential pressure applied to a valve core in the moving direction under the condition that the shape of the valve core is not restricted. In the flow rate control valve (1), the lower end (20a) of an outer tube member (20) is closed by a base member (10), and the upper end (20b) of the outer tube member (20) is closed by a holder body (71), forming a back pressure chamber (23) separated from a valve chamber (13). A drive shaft (64) is disposed across the valve chamber (13) and the back pressure chamber (23). The base member (10) is provided with a flow path (16) connected to the valve port (15) and a pressure equalizing hole (17) connecting the flow path (16) to the back pressure chamber (23).

Description

Flow control valve and method of assembling the same

Technical Field

The present invention relates to a flow rate control valve incorporated in, for example, a refrigeration cycle and used for controlling the flow rate of a fluid such as a refrigerant, and an assembling method thereof.

Background

Patent document 1 discloses a conventional pressure-balanced flow control valve. The flow rate control valve of patent document 1 includes a cylindrical guide portion provided in a valve housing and a valve body slidably provided in the guide portion. The valve body is moved in the axial direction (i.e., the moving direction) of the guide portion by the actuator to open and close the valve port. Further, the valve body is provided with a pressure equalizing path connecting the valve port and the back pressure chamber, thereby achieving pressure balance between the fluid pressure of the valve port and the fluid pressure of the back pressure chamber. This reduces the difference (differential pressure) between the fluid pressure applied to the valve body from the valve port side and the fluid pressure applied to the valve body from the back pressure chamber side.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2016-211600

However, in the flow rate control valve of patent document 1, since the vertical hole penetrating the valve body is provided as a leveling passage, the tip end of the valve body cannot be pointed. Therefore, the shape of the valve body is restricted. This makes it difficult to realize, for example, an equal percentage flow rate characteristic, and the flow rate characteristic is also restricted.

Disclosure of Invention

Accordingly, an object of the present invention is to provide a flow rate control valve and an assembling method thereof, which can effectively reduce a differential pressure applied to a valve body in a moving direction without restricting the shape of the valve body.

In order to achieve the above object, a flow rate control valve according to an aspect of the present invention includes: a base member provided with a valve chamber and a valve port opening to the valve chamber; an outer cylinder member disposed outside the base member; a valve element disposed opposite to the valve port and opening and closing the valve port; a drive shaft having the valve element provided at a distal end thereof; and a support member that supports the drive shaft so as to be movable in a direction in which the valve port and the valve body face each other, wherein one end of the outer tube member is closed by the base member, and the other end of the outer tube member is closed by the support member, and a back pressure chamber is formed so as to be partitioned from the valve chamber, the valve body or the drive shaft is disposed across the valve chamber and the back pressure chamber, and the base member is provided with a flow passage connected to the valve port and a pressure equalizing hole that connects the flow passage and the back pressure chamber.

According to the present invention, one end of the outer tube member is closed by the base member, and the other end of the outer tube member is closed by the support member, and a back pressure chamber is formed to be partitioned from the valve chamber. The spool or the drive shaft is disposed across the valve chamber and the back pressure chamber. The base member is provided with a flow path connected to the valve port and a pressure equalizing hole connecting the flow path to the back pressure chamber. Thus, the pressure equalizing hole provided in the base member can reduce the difference between the fluid pressure applied to the valve body from the valve port side and the fluid pressure applied to the valve body from the back pressure chamber side in the valve-closed state in which the valve port is closed by the valve body. Therefore, the differential pressure applied to the valve element in the moving direction can be effectively reduced without being restricted in the shape of the valve element.

In the present invention, it is preferable that the flow rate control valve includes a seal member formed in a ring shape through which the valve body or the drive shaft passes, and sealing a space between the valve chamber and the back pressure chamber, and a diameter of a seal portion sealed by the seal member is the same as a diameter of the valve port. Thus, in the valve-closed state, the difference between the fluid pressure applied to the valve body from the valve port side and the fluid pressure applied to the valve body from the back pressure chamber side can be made zero (including substantially zero). Therefore, the differential pressure applied to the valve element in the moving direction can be reduced more effectively without being restricted in the shape of the valve element.

In the present invention, it is preferable that the flow rate control valve is provided with a protrusion on one of the base member and the support member, and a hole into which the protrusion is inserted to restrict movement of the protrusion in a direction orthogonal to the opposing direction is provided on the other of the base member and the support member. For example, when the base member and the support member are assembled with each other through the outer tube member, the axis of the valve port and the axis of the valve body may be displaced due to the dimensional tolerances and the assembly accuracy of the base member and the outer tube member, and the support member and the outer tube member, respectively. In contrast, by providing the positioning protrusion on one of the base member and the support member and the positioning hole on the other of the base member and the support member, the base member and the support member are directly assembled, and thereby the axial displacement of the valve port and the valve element can be effectively suppressed.

In the present invention, it is preferable that the base member is provided with a circular hole as the hole, the circular hole being disposed coaxially with the valve port, and the support member is provided with a cylindrical portion as the projection, the cylindrical portion being disposed coaxially with the drive shaft. Thus, the axial displacement of the valve port and the valve element can be effectively suppressed with a relatively simple structure.

In the present invention, it is preferable that the cylindrical portion is press-fitted into the circular hole. This enables the base member and the support member to be more reliably assembled.

In the present invention, it is preferable that the cylindrical portion has a press-fitting end portion to be press-fitted into the circular hole and a main body portion continuous to the press-fitting end portion and having a diameter larger than a diameter of the press-fitting end portion, and a stepped portion between the press-fitting end portion and the main body portion is in contact with the base member. This allows the press-fitting end portion to be press-fitted into the circular hole until the step portion between the press-fitting end portion of the cylindrical portion and the main body portion comes into contact with the base member. Therefore, when the plurality of flow rate control valves are assembled, the amount of press-fitting (the size of the portion to be press-fitted) into the circular hole of the base member in the cylindrical portion of the support member can be made uniform.

In the present invention, it is preferable that the cylindrical portion has a press-fitting end portion to be press-fitted into the circular hole and a body portion continuous to the press-fitting end portion, and a protruding portion protruding outward in a radial direction from the press-fitting end portion is provided at an end portion of the body portion on the press-fitting end portion side, and the protruding portion abuts against the base member. This allows the press-fitting end portion to be press-fitted into the circular hole until the protruding portion of the cylindrical portion comes into contact with the base member. Therefore, when the plurality of flow rate control valves are assembled, the amount of press-fitting into the circular hole of the base member in the cylindrical portion of the support member can be made uniform.

In the present invention, it is preferable that the support member has a fitting portion fitted inside the outer cylindrical member, and an outer peripheral surface of the fitting portion is formed to be in contact with an inner peripheral surface of the outer cylindrical member. Thus, when the cylindrical portion of the support member is press-fitted into the circular hole of the base member, the outer peripheral surface of the fitting portion of the support member comes into contact with the inner peripheral surface of the outer cylindrical member, and the support member can be guided to move in the press-fitting direction. Therefore, the cylindrical portion can be suppressed from being pressed obliquely into the circular hole.

In the present invention, it is preferable that the support member has an abutting portion abutting against an end surface of the other end of the outer cylindrical member. Thus, the cylindrical portion can be press-fitted into the circular hole until the abutting portion of the support member abuts against the end face of the other end of the outer cylindrical member. Therefore, when the plurality of flow rate control valves are assembled, the amount of press-fitting into the circular hole of the base member in the cylindrical portion of the support member can be made uniform.

In the present invention, it is preferable that the flow rate control valve further includes a valve body driving portion including the driving shaft, the support member is disposed inside a housing of the valve body driving portion and the outer tube member, and the housing and the outer tube member are welded to each other. Thus, the case and the outer tube member are directly welded, and the number of welding points can be reduced as compared with a structure in which the case and the outer tube member of the valve element driving portion are welded to the support member, respectively.

In the present invention, it is preferable that the outer tube member is fixed to the support member in a state where the end surface of the other end of the outer tube member is in contact with the support member. Thus, when the plurality of flow rate control valves are assembled, the amount of press-fitting into the circular hole of the base member in the cylindrical portion of the support member can be made uniform.

In order to achieve the above object, a flow rate control valve according to another aspect of the present invention includes: a base member provided with a valve chamber and a valve port opening to the valve chamber; an outer cylinder member disposed outside the base member; a valve element disposed opposite to the valve port and opening and closing the valve port; a drive shaft having the valve element provided at a distal end thereof; and a support member that supports the drive shaft so as to be movable in a direction in which the valve port and the valve element face each other, the base member is provided with a flow path connected to the valve port and a pressure equalizing hole connecting the flow path to the outside of the base member, the method of assembling the flow rate control valve is characterized in that one end of the outer tube member is closed by the base member, a cylindrical portion provided in the support member and arranged coaxially with the drive shaft is press-fitted into a circular hole provided in the base member and arranged coaxially with the valve port, the press-fitting of the cylindrical portion is advanced until the other end of the outer tube member comes into contact with the support member, and the other end of the outer tube member is closed by the support member, thereby forming a back pressure chamber that is partitioned from the valve chamber outside the base member, and the valve body or the drive shaft is disposed across the valve chamber and the back pressure chamber.

According to the present invention, one end of the outer cylinder member is closed by the base member. A cylindrical portion provided in the support member and arranged coaxially with the drive shaft is press-fitted into a circular hole provided in the base member and arranged coaxially with the valve port. The cylindrical portion is pushed until the other end of the outer tube member abuts against the support member, and the other end of the outer tube member is closed by the support member, whereby a back pressure chamber is formed outside the base member, the back pressure chamber being defined from the valve chamber, and the valve body or the drive shaft being disposed across the valve chamber and the back pressure chamber. Thus, the cylindrical portion of the support member is press-fitted into the circular hole of the base member, and the base member and the support member are directly assembled, whereby the axial displacement of the valve port and the valve element can be effectively suppressed with a relatively simple structure. Further, the base member and the support member can be more reliably assembled by press-fitting the cylindrical portion into the circular hole. Further, by pushing the cylindrical portion until the other end of the outer tube member comes into contact with the support member, the other end of the outer tube member is closed by the support member, and thus, when the plurality of flow rate control valves are assembled, the amount of pushing in the cylindrical portion of the support member into the circular hole of the base member can be made uniform.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, it is possible to effectively reduce the differential pressure applied to the valve element in the moving direction without being restricted in the shape of the valve element.

Drawings

Fig. 1 is a vertical sectional view (open valve state) of a flow rate control valve according to a first embodiment of the present invention.

Fig. 2 is a longitudinal sectional view (closed valve state) of the flow rate control valve of fig. 1.

Fig. 3 is an enlarged sectional view of a valve body of the flow control valve of fig. 1 and its vicinity.

Fig. 4 is a vertical sectional view (open valve state) showing a structure of a modified example of the flow rate control valve of fig. 1.

Fig. 5 is a vertical cross-sectional view (closed valve state) showing a structure of a modification of the flow rate control valve of fig. 1.

Fig. 6 is an enlarged cross-sectional view of a valve body of a flow rate control valve according to a second embodiment of the present invention and its vicinity.

Fig. 7 is an enlarged cross-sectional view of a valve body of a flow rate control valve according to a third embodiment of the present invention and its vicinity.

Detailed Description

(first embodiment)

A flow rate control valve according to a first embodiment of the present invention will be described below with reference to fig. 1 to 4.

Fig. 1 and 2 are vertical sectional views (open state and closed state) of a flow rate control valve according to a first embodiment of the present invention. Fig. 3 is an enlarged sectional view of a valve body of the flow control valve of fig. 1 and its vicinity. Fig. 4 and 5 are vertical sectional views (open state and closed state) showing the structure of a modified example of the flow rate control valve shown in fig. 1.

The flow rate control valve 1 of the present embodiment is an electrically operated valve used for adjusting the flow rate of refrigerant in a refrigeration cycle or the like, for example.

The flow rate control valve 1 includes a valve main body 5, a valve body 6, and a valve body driving unit 8.

The valve main body 5 has a base member 10 and an outer cylinder member 20.

The base member 10 is made of, for example, a stainless steel material. The base member 10 is formed in a bottomed cylindrical shape as a whole. The base member 10 integrally includes a substantially cylindrical base body 11 and a bottom wall 12 provided at a lower end of the base body 11.

The base body 11 is provided with a valve chamber 13 as a cylindrical space. The base body 11 is provided with a circular hole 14 as a positioning hole opened upward. The circular hole 14 is connected to the valve chamber 13. In the present embodiment, the diameter of the valve chamber 13 is the same as the diameter of the circular hole 14.

The bottom wall 12 is provided with: a circular valve port 15 opening to the valve chamber 13; a flow path 16 connected to the valve port 15 and extending downward; a pressure equalizing hole 17 extending in the lateral direction from the flow path 16; and a valve seat 18 surrounding the valve port 15. The valve port 15 and the flow passage 16 are provided coaxially with the valve chamber 13 and have a smaller diameter than the valve chamber 13. The pressure equalizing hole 17 connects the flow path 16 to a back pressure chamber 23, which will be described later, formed outside the base member 10. The valve element 6 is seated on the valve seat 18.

The outer tube member 20 is formed of, for example, a stainless steel material and is formed in a cylindrical shape. The outer tube member 20 is disposed outside the base member 10, and accommodates the base member 10 inside. The bottom wall 12 of the base member 10 is fitted into a lower end 20a, which is one end of the outer cylindrical member 20, and the lower end 20a is closed by the base member 10. The lower end 20a of the outer cylindrical member 20 is brazed to the bottom wall 12.

The valve body 5 has a first conduit 26 extending transversely through the outer cylindrical member 20 and the base body 11 and connected to the valve chamber 13. The first duct 26 is brazed to the outer cylindrical member 20. The valve main body 5 has a second conduit 27 connected to the flow path 16 of the base main body 11. The second conduit 27 is brazed to the bottom wall 12 of the base body 11.

The valve body 6 is made of, for example, a stainless steel material. The valve body 6 is formed in a solid (i.e., not hollow) cylindrical shape as a whole, and has a substantially conical shape facing downward at a lower end. The valve body 6 integrally includes a cylindrical body portion 31, a substantially conical tip portion 32 provided at the lower end of the body portion 31 and directed downward, and an annular protrusion 33 protruding in the lateral direction from the lower end of the body portion 31. The upper end surface 31a of the body portion 31 is provided with a mounting hole 31 b. A distal end protrusion 64e of a distal end portion 64c of the drive shaft 64 described later is fitted into the mounting hole 31 b. Thereby, the valve body 6 is provided at the distal end portion 64c of the drive shaft 64. The body portion 31 is provided with a lateral hole 31c that penetrates in the lateral direction from the attachment hole 31 b. The fluid pressure in the mounting hole 31b is made equal to the fluid pressure outside the valve body 6 by the lateral hole 31c, and the tip end projection 64e is prevented from coming out of the mounting hole 31 b.

The valve body 6 is disposed in the valve chamber 13 so as to face the valve port 15 in the vertical direction. The valve body 6 is moved in the vertical direction by the valve body driving unit 8 to open and close the valve port 15. The vertical direction is a direction in which the valve port 15 faces the valve body 6, and is a moving direction of the valve body 6. When the valve element 6 is separated from the valve seat 18, the valve port 15 is opened to be in an open state. In the valve-open state, the first conduit 26 and the second conduit 27 are connected via the valve chamber 13. When the valve element 6 contacts the valve seat 18 (is seated on the valve seat 18), the valve port 15 is closed and a valve-closed state is achieved. In the valve-closed state, the first conduit 26 and the second conduit 27 are cut off.

The tip portion 32 of the valve body 6 has a solid structure, and thus there is no limitation on the shape of the tip portion 32. Therefore, the shape of the distal end portion 32 of the valve element 6 may be designed so as to obtain the same percentage characteristic or a characteristic close to the same as the flow rate characteristic. As such a shape, for example, there is a shape having an elliptical surface or a multi-stage conical tapered surface portion. The tapered surface portion of the multistage cone shape is a pseudo-elliptical surface, and the taper angle gradually increases as the valve port 15 side approaches. Alternatively, the shape of the distal end portion 32 of the valve element 6 may be designed so as to obtain a linear characteristic as the flow rate characteristic.

The valve body drive portion 8 is attached to the upper portion of the valve main body 5. The valve body driving unit 8 moves the valve body 6 in the vertical direction to bring the valve body 6 into contact with and away from the valve seat 18, thereby closing or opening the valve port 15. The valve body driving unit 8 includes a housing 40 as a casing, a motor unit 50, a driving mechanism unit 60, and a holder 70.

The housing 40 is made of, for example, a stainless steel material. The housing 40 is formed in a cylindrical shape with the upper end closed. A holder 70 (specifically, a holder body 71) described later is fitted into the lower end 40a of the housing 40, and the lower end 40a is closed by the holder 70. The lower end 40a of the outer shell 40 is welded to the holder 70.

The motor unit 50 includes: a rotor 51, the rotor 51 being rotatably housed inside the housing 40; and a stator 52, the stator 52 being disposed outside the housing 40. The stator 52 is constituted by a yoke 53, a bobbin 54, a stator coil 55, a resin mold cover 56, and the like. The rotor 51 and the stator 52 constitute a stepping motor.

The drive mechanism section 60 includes a guide bush 61, a valve shaft holder 62, a stopper mechanism 63, a drive shaft 64, and a seal member 65.

The guide bush 61 integrally has a cylindrical small diameter portion 61a and a cylindrical large diameter portion 61b coaxially connected to a lower end of the small diameter portion 61 a. The inner diameter of the small diameter portion 61a is the same as that of the large diameter portion 61 b. A male screw 61c is provided on the outer peripheral surface of the small diameter portion 61 a. The small-diameter portion 61a is provided with a transverse hole 61d penetrating in the transverse direction.

The valve shaft holder 62 is formed in a cylindrical shape with the upper end closed. The valve shaft holder 62 integrally has a cylindrical peripheral wall portion 62a and an upper wall portion 62b that closes the upper end of the peripheral wall portion 62 a. An internal thread 62c that is screwed into the external thread 61c of the guide bush 61 is provided on the inner peripheral surface of the peripheral wall portion 62 a. The upper wall 62b is integrally connected to the rotor 51 via a support ring 66 that is fixed to the upper wall 62b by caulking. Therefore, when the rotor 51 rotates, the valve shaft holder 62 also rotates. When the valve shaft holder 62 is rotated, the valve shaft holder 62 moves in the axial direction (vertical direction) of the guide bush 61 by the feed screw action of the male screw 61c and the female screw 62 c. Further, a return spring 67 formed of a coil spring is provided above the valve shaft holder 62, and the return spring 67 is used to facilitate the re-screwing of the external thread 61c and the internal thread 62c when they are disengaged from each other.

The stopper mechanism 63 has a lower stopper body 63a fixed to the guide bush 61 and an upper stopper body 63b fixed to the valve shaft holder 62. When the valve shaft holder 62 reaches the lower limit position, the lower stopper body 63a and the upper stopper body 63b of the stopper mechanism 63 abut against each other, and the movement of the valve shaft holder 62 with respect to the guide bush 61 is restricted.

The drive shaft 64 is formed in an elongated cylindrical shape as a whole. The drive shaft 64 is inserted through the guide bush 61 and is disposed coaxially with the guide bush 61. The drive shaft 64 is integrally provided with an upper end portion 64a, a body portion 64b, and a distal end portion 64c in this order from the top downward. The upper end portion 64a is formed to have a diameter smaller than that of the body portion 64b, and is inserted into a through hole of the upper wall portion 62b of the valve shaft holder 62. A pushing nut 64d is fixed to the upper end portion 64 a. The body portion 64b is supported by the guide bush 61 so as to be slidable in the vertical direction. A compression coil spring 68 that always presses the drive shaft 64 downward is provided between the stepped portion of the upper end portion 64a and the body portion 64b and the upper wall portion 62b of the valve shaft holder 62. By providing the urging nut 64d and the compression coil spring 68, the drive shaft 64 moves in the up-down direction in accordance with the movement of the valve shaft holder 62. The distal end portion 64c is provided with a slender distal end protrusion 64e that fits into the attachment hole 31b of the body portion 31 of the valve body 6. The drive shaft 64 is integrally provided with a flange portion 64f projecting in the lateral direction at the lower end of the body portion 64 b. The diameter of the flange portion 64f is the same as the diameter of the body portion 31 of the valve body 6.

The seal member 65 is formed in an annular shape. The seal member 65 has a distal end portion 64c of the drive shaft 64 fitted inside. That is, the distal end portion 64c of the drive shaft 64 penetrates the seal member 65. The seal member 65 is disposed between the flange portion 64f and the upper end surface 31a of the body portion 31 of the valve body 6. In the present embodiment, the seal member 65 is provided with an annular packing 65b made of Polytetrafluoroethylene (PTFE) on the outer side of an O-ring 65a made of a rubber material.

The holder 70 is made of, for example, a stainless steel material. The holder 70 integrally includes a substantially disc-shaped holder main body 71 and a cylindrical portion 72 serving as a positioning protrusion. The cylindrical portion 72 protrudes downward from the lower surface 71a of the holder main body 71.

The end surface 20c of the upper end 20b, which is the other end of the outer tubular member 20, is welded to the holder main body 71 in a state in which the end surface 20b is in contact with the lower surface 71a of the holder main body 71. The upper end 20b of the outer cylindrical member 20 is closed by the holder body 71. Thereby, the back pressure chamber 23 partitioned from the valve chamber 13 is formed by the base member 10, the outer tube member 20, and the holder body 71. In addition, the lower end 40a of the outer shell 40 is welded to the holder main body 71.

A circular press-fitting hole 71b is provided in the center of the upper surface of the holder main body 71, coaxially with the cylindrical portion 72. The large diameter portion 61b of the guide bush 61 is press-fitted into the press-fitting hole 71 b. Thus, the holder main body 71 and the guide bush 61 are integrated with each other in a state where the guide bush 61 and the cylindrical portion 72 are coaxially arranged. The holder 70 and the guide bush 61 constitute a support member 69 that supports the drive shaft 64 so as to be movable in the direction in which the valve port 15 and the valve element 6 oppose each other. A shaft hole 71c through which the body portion 64b of the drive shaft 64 is inserted is provided in the center of the bottom surface of the press-fitting hole 71 b. A vertical hole 71d penetrating in the vertical direction is provided in the peripheral edge portion of the holder main body 71.

The cylindrical portion 72 is press-fitted into the circular hole 14 of the base member 10. Thus, the holder 70 is directly assembled to the base member 10, and the cylindrical portion 72 and the circular hole 14 are coaxially arranged. The cylindrical portion 72 and the valve port 15 are also coaxially arranged. Further, by inserting the cylindrical portion 72 into the circular hole 14, the circular hole 14 restricts the movement of the cylindrical portion 72 in a direction orthogonal to the vertical direction (the opposing direction).

Inside the cylindrical portion 72, the body portion 31 of the valve body 6, the distal end portion 64c and the flange portion 64f of the drive shaft 64, and the seal member 65 are disposed so as to be movable in the vertical direction. The gasket 65b disposed on the outer periphery of the seal member 65 is pressed against the inner surface of the cylindrical portion 72. Thereby, the seal member 65 seals between the valve chamber 13 and the back pressure chamber 23. The seal member 65 slides on the inner circumferential surface of the cylindrical portion 72 in accordance with the vertical movement of the drive shaft 64. A transverse hole 72a penetrating in the transverse direction is provided at the upper end of the cylindrical portion 72. In the present embodiment, the inner diameter of the cylindrical portion 72 (i.e., the diameter of the seal portion sealed by the seal member 65) is the same as the diameter of the valve port 15. The inner diameter of the cylindrical portion 72 may be different from the diameter of the valve port 15, but the difference is preferably reduced.

In the flow rate control valve 1, the valve chamber 13 and the back pressure chamber 23 are sealed by the seal member 65 fitted into the distal end portion 64c of the drive shaft 64, and therefore the drive shaft 64 is disposed across the valve chamber 13 and the back pressure chamber 23. The flow passage 16 of the base member 10 and the back pressure chamber 23 are connected to each other through the pressure equalizing hole 17 of the base member 10. The back pressure chamber 23 and the inner space 41 of the housing 40 are connected by a vertical hole 71d of the holder body 71. Therefore, in the valve-closed state, the fluid pressure in the flow path 16 is the same as the fluid pressure in the back pressure chamber 23, and the difference (differential pressure) between the fluid pressure applied to the valve body 6 from the valve port 15 side and the fluid pressure applied to the valve body 6 from the back pressure chamber 23 side becomes small. In the present embodiment, the diameter of the valve port 15 (indicated by a double arrow D1 in fig. 3) is made equal to the inner diameter of the cylindrical portion 72 of the holder 70 (indicated by a double arrow D2 in fig. 3). Therefore, the differential pressure is zero (including substantially zero), and it is possible to effectively prevent the valve element 6 from being prevented from moving by the differential pressure.

A space 72b inside the cylindrical portion 72 and above the flange portion 64f is connected to the back pressure chamber 23 through a lateral hole 72 a. The space 72b is also connected to the back pressure chamber 23 through the inner space 41 of the housing 40, the lateral hole 61d of the guide bush 61, a gap between the guide bush 61 and the drive shaft 64, and the shaft hole 71c of the holder 70. Thus, even when the fluid pressure in the space 72b changes due to the movement of the flange portion 64f, the fluid pressure in the space 72b is quickly equal to the fluid pressure in the back pressure chamber 23.

Next, a method of assembling the flow rate control valve 1 will be described.

(1) The valve body 5 is assembled. Specifically, the base member 10 is fitted into the lower end 20a of the outer tube member 20, and the lower end 20a is closed. The first guide pipe 26 is fitted into the outer tube member 20 and the base body 11 of the base member 10. The second conduit 27 is embedded in the bottom wall 12 of the base part 10. Then, brazing is performed by providing a brazing material at each brazing portion and charging the brazing material into a furnace.

(2) The valve body driving portion 8 is assembled. Specifically, the large diameter portion 61b of the guide bush 61 is press-fitted into the press-fitting hole 71b of the holder main body 71, and the holder main body 71 and the guide bush 61 are integrated. The internal thread 62c of the valve shaft holder 62 is screwed with the external thread 61c of the guide bush 61. The lower stopper 63a is mounted in advance on the guide bush 61. The upper stop body 63b is mounted in advance on the valve shaft holder 62. The rotor 51 is coupled to the valve shaft holder 62 in advance via a support ring 66. The tip end portion 64c of the drive shaft 64 is fitted into the seal member 65, and the tip end protrusion 64e of the tip end portion 64c is fitted into the mounting hole 31b of the valve body 6, whereby the valve body 6 is mounted on the drive shaft 64. The drive shaft 64 is inserted from below into the cylindrical portion 72 of the holder 70, the shaft hole 71c of the holder 70, and the guide bush 61. A compression coil spring 68 is provided at the upper end portion 64a of the drive shaft 64, and the upper end portion 64a is inserted into the through hole of the upper wall portion 62b of the valve shaft holder 62. A jack nut 64d is fixed to the upper end 64a of the drive shaft 64, and a return spring 67 is disposed. Then, an assembly in which the rotor 51, the guide bush 61, the valve shaft holder 62, the stopper mechanism 63, and the like are assembled is inserted into the housing 40. A holder body 71 is fitted into the lower end 40a of the housing 40, and the lower end 40a is closed by the holder body 71. The lower end 40a of the outer shell 40 is welded to the holder main body 71. The stator 52 is mounted to the housing 40. In this state, the drive shaft 64 and the valve body 6 are disposed coaxially with the cylindrical portion 72.

(3) Then, the valve main body 5 and the valve element driving portion 8 are assembled. Specifically, the cylindrical portion 72 is press-fitted into the circular hole 14 of the base member 10. The push cylinder portion 72 is pushed until the end surface 20c of the upper end 20b of the outer tube member 20 abuts against the holder main body 71, and the holder main body 71 closes the upper end 20b, thereby forming the back pressure chamber 23 outside the base member 10, which is partitioned from the valve chamber 13. Meanwhile, the drive shaft 64 is disposed so as to straddle the valve chamber 13 and the back pressure chamber 23. Finally, the upper end 20b of the outer cylindrical member 20 is welded to the holder main body 71. Thus, the flow control valve 1 is completed.

As described above, according to the flow rate control valve 1 of the present embodiment, the lower end 20a of the outer tube member 20 is closed by the base member 10, and the upper end 20b of the outer tube member 20 is closed by the holder body 71, forming the back pressure chamber 23 partitioned from the valve chamber 13. The drive shaft 64 is disposed across the valve chamber 13 and the back pressure chamber 23. The base member 10 is provided with a flow passage 16 connected to the valve port 15 and a pressure equalizing hole 17 connecting the flow passage 16 to the back pressure chamber 23. Accordingly, the pressure equalizing hole 17 provided in the base member 10 can reduce the difference between the fluid pressure applied to the valve body 6 from the valve port 15 side and the fluid pressure applied to the valve body 6 from the back pressure chamber 23 side in the valve closed state. Therefore, the differential pressure applied to the valve element 6 in the moving direction can be effectively reduced without being restricted in the shape of the valve element 6.

The flow rate control valve 1 further includes a seal member 65, and the seal member 65 is formed in an annular shape through which the drive shaft 64 passes, and seals between the valve chamber 13 and the back pressure chamber 23. The inner diameter of the cylindrical portion 72 (which is the diameter of the seal portion sealed by the seal member 65 and indicated by double-headed arrow D2 in fig. 3) is the same as the diameter of the valve port 15 (indicated by double-headed arrow D1 in fig. 3). Thus, in the valve-closed state, the difference between the fluid pressure applied to the valve body 6 from the valve port 15 side and the fluid pressure applied to the valve body 6 from the back pressure chamber 23 side can be made zero. Therefore, the differential pressure applied to the valve element 6 in the moving direction can be reduced more effectively without being restricted in the shape of the valve element 6.

In the flow rate control valve 1, the circular hole 14 disposed coaxially with the valve port 15 is provided in the base member 10, and the cylindrical portion 72 disposed coaxially with the drive shaft 64 is provided in the holder 70. The cylindrical portion 72 is press-fitted into the circular hole 14. This allows the base member 10 and the holder 70 to be directly assembled, and axial displacement between the valve port 15 and the valve body 6 to be effectively suppressed with a relatively simple structure. Further, the base member 10 and the holder 70 can be more reliably assembled by press fitting.

Further, the outer tube member 20 and the holder main body 71 are fixed by welding in a state where the end face 20c of the upper end 20b of the outer tube member 20 is in contact with the holder main body 71. Thus, when the plurality of flow rate control valves 1 are assembled, the amount of press-fitting of the cylindrical portion 72 into the circular hole 14 of the base member 10 can be made uniform.

In the above-described embodiment, the cylindrical portion 72 of the holder 70 is press-fitted into the circular hole 14 of the base member 10, but other configurations may be employed. For example, the following structure may be adopted: the cylindrical portion 72 is inserted into the circular hole 14, and a sealing member such as an O-ring is provided between the outer peripheral surface of the cylindrical portion 72 and the inner peripheral surface of the circular hole 14.

In the above-described embodiment, the valve body 6 and the drive shaft 64 are separately configured, but the valve body 6 and the drive shaft 64 may be integrally configured, for example, as in the flow rate control valve 1A shown in fig. 4 and 5. In this configuration, the spool 6 includes the drive shaft 64, and the spool 6 is disposed across the valve chamber 13 and the back pressure chamber 23. The seal member 65 is formed in an annular shape through which the valve body 6 passes, and seals between the valve chamber 13 and the back pressure chamber 23.

In the above-described embodiment, the circular hole 14 as the positioning hole is provided in the base member 10, and the cylindrical portion 72 as the positioning protrusion is provided in the holder 70, but the positioning protrusion may be provided in the base member 10 and the positioning hole may be provided in the holder 70, in contrast to this.

(second embodiment)

A flow rate control valve according to a second embodiment of the present invention will be described below with reference to fig. 6.

Fig. 6 is an enlarged cross-sectional view of a valve body of a flow rate control valve according to a second embodiment of the present invention and its vicinity. In the flow rate control valve 2 according to the second embodiment shown in fig. 6, the same components as those of the flow rate control valve 1 are denoted by the same reference numerals, and description thereof is omitted.

The flow control valve 2 has a holder 70A having a structure different from that of the holder 70 of the flow control valve 1.

The holder 70A is made of, for example, a stainless steel material. The holder 70A integrally includes a substantially disc-shaped holder main body 71A and a cylindrical portion 72A serving as a positioning projection. The cylindrical portion 72A protrudes downward from the lower surface 71A of the holder main body 71A.

The outer diameter of the holder main body 71A is the same as the inner diameter of the outer cylindrical member 20. The holder body 71A corresponds to a fitting portion, and is fitted inside the upper end 20b of the outer tube member 20. The upper end 20b of the outer cylindrical member 20 is closed by the holder body 71A. The holder 70A and the guide bush 61 constitute a support member 69A. The support member 69A is disposed inside the outer shell 40 and the outer tube member 20. The lower end 40a of the outer shell 40 is welded to the upper end 20b of the outer cylindrical member 20. By directly welding the outer shell 40 and the outer cylindrical member 20, the number of welding points can be reduced as compared with the flow control valve 1 according to the first embodiment in which the outer shell 40 and the outer cylindrical member 20 are welded to the holder 70, respectively.

The cylindrical portion 72A has a press-fitting end portion 72c as a distal end portion and a body portion 72 d. The pressed end portion 72c and the body portion 72d are connected in the vertical direction. The body portion 72d is formed to have a larger diameter than the press-fit end portion 72 c. A stepped portion 72e is formed between the press-fitting end portion 72c and the body portion 72 d. The press-fitting end portion 72c is press-fitted into the circular hole 14 until the step portion 72e abuts against the base member 10. Thus, the holder 70A is directly assembled to the base member 10, and the cylindrical portion 72A is disposed coaxially with the circular hole 14 (i.e., the valve port 15). The circular hole 14 restricts the movement of the cylindrical portion 72A in a direction orthogonal to the vertical direction (opposing direction). Further, the stepped portion 72e of the cylindrical portion 72A abuts against the base member 10. Therefore, when the plurality of flow rate control valves 2 are assembled, the amount of press-fitting into the circular hole 14 of the base member 10 in the cylindrical portion 72A can be made uniform.

The holder body 71A is fitted inside the upper end 20b of the outer tube member 20. Further, since the outer diameter of the holder main body 71A is the same as the inner diameter of the outer tube member 20, the outer peripheral surface of the holder main body 71A is formed to be in contact with the inner peripheral surface of the outer tube member 20. Thus, when the press-fitting end 72c of the cylindrical portion 72A is press-fitted into the circular hole 14 of the base member 10, the outer peripheral surface of the holder main body 71A is in contact with the inner peripheral surface of the outer tube member 20 and is guided to move in the vertical direction (press-fitting direction). Therefore, the press-fitting end portion 72c of the cylindrical portion 72A can be suppressed from being pressed into the circular hole 14 obliquely.

In the present embodiment, the cylindrical portion 72A has a stepped portion 72e between the press-fitting end portion 72c and the body portion 72 d. In addition to this structure, the following structure may be adopted. That is, the cylindrical portion 72A has a press-fitting end portion 72c as a distal end portion and a body portion 72d continuous with the press-fitting end portion 72 c. A protruding portion protruding radially outward from the press-fitting end portion 72c is provided at the end portion of the body portion 72d on the press-fitting end portion 72c side. The protruding portion is provided with one or a plurality of protruding portions spaced apart in the circumferential direction, for example. The protruding portion abuts on the base member 10. In this configuration, the press-fitting end portion 72c is press-fitted into the circular hole 14 until the protruding portion abuts against the base member 10, whereby the amount of press-fitting into the circular hole 14 of the base member 10 in the cylinder portion 72A can be made uniform even when a plurality of flow rate control valves are assembled.

(third embodiment)

A flow rate control valve according to a third embodiment of the present invention will be described below with reference to fig. 7.

Fig. 7 is an enlarged cross-sectional view of a valve body of a flow rate control valve according to a third embodiment of the present invention and its vicinity. In the flow rate control valve 3 according to the third embodiment shown in fig. 7, the same components as those of the flow rate control valve 1 are denoted by the same reference numerals, and description thereof is omitted.

The flow control valve 3 has a holder 70B having a structure different from that of the holder 70 of the flow control valve 1.

The holder 70B is made of, for example, a stainless steel material. The holder 70B integrally includes a substantially disc-shaped holder main body 71B and a cylindrical portion 72B serving as a positioning protrusion. The cylindrical portion 72B protrudes downward from the lower surface 71a of the holder main body 71B.

The holder main body 71B has a fitting portion 71e and an abutting portion 71 f. The fitting portion 71e is formed in a cylindrical shape and has the same outer diameter as the inner diameter of the outer cylindrical member 20. The fitting portion 71e is fitted inside the upper end 20b of the outer tube member 20. The contact portion 71f is an annular projection provided on the upper end of the outer peripheral surface of the fitting portion 71e to project radially outward. The outer diameter of the abutment portion 71f is formed to be the same as the inner diameter of the housing 40. The contact portion 71f contacts the end surface 20c of the upper end 20b of the outer cylindrical member 20. The upper end 20B of the outer cylindrical member 20 is closed by the holder body 71B. The holder 70B and the guide bush 61 constitute a support member 69B. The support member 69B is disposed inside the outer shell 40 and the outer tube member 20. The lower end 40a of the outer shell 40 is welded to the upper end 20b of the outer cylindrical member 20.

The cylindrical portion 72B is press-fitted into the circular hole 14 of the base member 10. The contact portion 71f of the holder main body 71B contacts the end surface 20c of the upper end 20B of the outer cylindrical member 20. Therefore, when the plurality of flow rate control valves 3 are assembled, the amount of press-fitting into the circular hole 14 of the base member 10 in the cylindrical portion 72B can be made uniform.

The fitting portion 71e of the holder main body 71B is fitted inside the upper end 20B of the outer tube member 20. Since the outer diameter of the fitting portion 71e is the same as the inner diameter of the outer cylindrical member 20, the outer peripheral surface of the fitting portion 71e is formed in contact with the inner peripheral surface of the outer cylindrical member 20. Thus, when the cylindrical portion 72B is press-fitted into the circular hole 14 of the base member 10, the outer peripheral surface of the fitting portion 71e is in contact with the inner peripheral surface of the outer cylindrical member 20 and is guided to move in the vertical direction (press-fitting direction). Therefore, the cylindrical portion 72B can be suppressed from being pressed obliquely into the circular hole 14.

The embodiments of the present invention have been described above, but the present invention is not limited to these embodiments. Those skilled in the art can appropriately add, delete, and modify the components of the above-described embodiments, and appropriately combine the features of the embodiments, without departing from the spirit of the present invention, and the scope of the present invention is also encompassed.

Description of the symbols

(first embodiment)

1. 1a … flow control valve, 5 … valve body, 6 … valve core, 8 … valve core driving part, 10 … base part, 11 … base body, 12 … bottom wall, 13 … valve chamber, 14 … circular hole, 15 … valve port, 16 … flow path, 17 … pressure equalizing hole, 18 … valve seat, 20 … outer cylinder part, 20a … lower end, 20b … upper end, 23 … chamber, 26 … first conduit, 27 … second conduit, 31 … trunk, 31a … upper end face, 31b … mounting hole, 31c … transverse hole, coil former … top end, 33 … annular projection, 40 … housing, 40a … lower end, 41 … inner space, 50 … electric machine part, 51 … rotor, 52 … stator, … yoke, 3654 …, 55 …, 56 stator coil 72 resin molded bushing, … driving mechanism 61, … guide portion, … a guide …, … small diameter portion, … d, … external thread …, … transverse hole, … d, … transverse hole, …, 62 … valve shaft holder, 62a … peripheral wall, 62b … upper wall, 62c … internal thread, 63 … locking mechanism, 63a … lower locking body, 63b … upper locking body, 64 … drive shaft, 64a … upper end, 64b … trunk, 64c … top end, 64d … push nut, 64e … top end projection, 64f … flange, 65 … sealing member, 65a … O ring, 65b … gasket, 66 … supporting ring, 67 … return spring, 68 … compression coil spring, 69 … supporting member, 70 … holder, 71 … holder body, 71a … lower surface, 71b … press-in hole, 71c … shaft hole, 71d … longitudinal hole, 72 … cylinder part, 72a … transverse hole, 71d,

(second embodiment)

2 … flow control valve, 69A … support member, 70A … holder, 71A … holder body, 72A … cylindrical part, 72c … press-fit end part, 72d … body part, 72e … stepped part,

(third embodiment)

3 … flow control valve, 69B … support member, 70B … holder, 71B … holder main body, 72B … cylindrical portion, 71e … fitting portion, 71f … abutting portion.

Claims

1. A flow control valve, comprising:

a base member provided with a valve chamber and a valve port opening to the valve chamber;

an outer cylinder member disposed outside the base member;

a valve element disposed opposite to the valve port and opening and closing the valve port;

a drive shaft having the valve element provided at a distal end thereof; and

a support member that supports the drive shaft so as to be movable in a direction in which the valve port and the valve element face each other,

one end of the outer tube member is closed by the base member, and the other end of the outer tube member is closed by the support member, forming a back pressure chamber partitioned from the valve chamber,

the valve body or the drive shaft is disposed across the valve chamber and the back pressure chamber,

the base member is provided with a flow path connected to the valve port and a pressure equalizing hole connecting the flow path to the back pressure chamber.

2. The flow control valve of claim 1,

a seal member formed in an annular shape through which the valve body or the drive shaft passes and sealing a space between the valve chamber and the back pressure chamber,

the diameter of the sealing part sealed by the sealing component is the same as that of the valve port.

3. The flow control valve according to claim 1 or 2,

a protrusion is provided on one of the base member and the support member, and a hole into which the protrusion is inserted to restrict the movement of the protrusion in a direction orthogonal to the opposing direction is provided on the other of the base member and the support member.

4. The flow control valve of claim 3,

the base member is provided with a circular hole disposed coaxially with the valve port as the hole,

the support member is provided with a cylindrical portion disposed coaxially with the drive shaft as the projection.

5. The flow control valve of claim 4,

the cylindrical portion is pressed into the circular hole.

6. The flow control valve of claim 5,

the cylindrical portion has a press-fitting end portion to be press-fitted into the circular hole and a body portion connected to the press-fitting end portion and having a diameter larger than that of the press-fitting end portion,

the step between the press-fitting end portion and the main body portion abuts against the base member.

7. The flow control valve of claim 5,

the cylindrical portion has a press-fitting end portion to be press-fitted into the circular hole and a body portion continuous to the press-fitting end portion,

a protruding portion protruding outward in the radial direction from the press-fitting end portion is provided at an end portion of the main body portion on the press-fitting end portion side,

the protruding portion abuts against the base member.

8. The flow control valve according to any one of claims 5 to 7,

the support member has a fitting portion fitted to the inner side of the outer cylinder member,

the outer peripheral surface of the fitting portion is formed to be in contact with the inner peripheral surface of the outer tube member.

9. The flow control valve of claim 5,

the support member has an abutting portion abutting against an end surface of the other end of the outer tube member.

10. The flow control valve according to any one of claims 5 to 9,

also comprises a valve core driving part containing the driving shaft,

the support member is disposed inside the housing of the valve element drive unit and the outer cylinder member,

the housing and the outer cylindrical member are welded.

11. The flow control valve of claim 5,

the outer tube member is fixed to the support member in a state where the end surface of the other end of the outer tube member is in contact with the support member.

12. A method of assembling a flow control valve, the flow control valve having: a base member provided with a valve chamber and a valve port opening to the valve chamber; an outer cylinder member disposed outside the base member; a valve element disposed opposite to the valve port and opening and closing the valve port; a drive shaft having the valve element provided at a distal end thereof; and a support member that supports the drive shaft so as to be movable in a direction in which the valve port and the valve body face each other, wherein the base member is provided with a flow passage that connects the valve port and a pressure equalizing hole that connects the flow passage to an outside of the base member, and wherein the flow rate control valve is assembled in a manner such that the pressure equalizing hole is formed in the base member,

closing one end of the outer cylinder member with the base member,

a cylindrical portion provided in the support member and arranged coaxially with the drive shaft is press-fitted into a circular hole provided in the base member and arranged coaxially with the valve port,

the press-fitting of the cylindrical portion is advanced until the other end of the outer tube member abuts against the support member, and the other end of the outer tube member is closed by the support member, whereby a back pressure chamber is formed outside the base member, the back pressure chamber being defined from the valve chamber, and the valve body or the drive shaft is disposed across the valve chamber and the back pressure chamber.