JP6515164B2 - Flow control valve - Google Patents

Description

  The present invention relates to a flow control valve incorporated in a refrigeration cycle or the like and used for flow control of a fluid such as a refrigerant.

  Conventionally, as a flow control valve of this type, a pressure balance type one that cancels a differential pressure applied to a valve body has been proposed. As such a pressure balance type flow control valve, for example, a cylindrical guide portion disposed in a valve body (valve housing), and slidably disposed in the guide portion and defined by a valve seat And a drive actuator for driving the valve body in the axial direction of the guide portion, and the valve body is moved in the axial direction to open and close the valve port, and The back pressure chamber on the opposite side of the valve port to the valve body and the valve port are conducted by a pressure equalizing passage to balance the fluid pressure of the back pressure chamber and the fluid pressure of the valve port. Those are known (see, for example, Patent Documents 1 and 2 below).

JP, 2016-211600, A JP 2001-241562 A JP, 2017-089864, A

  However, the conventional techniques described in Patent Documents 1 and 2 have the following problems to be solved.

  That is, in the prior art described in the above-mentioned patent documents 1, the equal pressure passage which connects a valve mouth and a back pressure room is constituted by the vertical hole which penetrates a valve body in the direction of an axis. Therefore, for example, it is necessary to form a through hole in a thin valve body, and it is difficult to process the pressure equalizing passage (through hole). In addition, since it is not possible to form a pointed tip shape, it is not possible to adopt, for example, a tip shape that achieves equal percentage flow (see, for example, Patent Document 3 above), and the tip shape of the valve body and, in turn, the flow characteristics are restricted.

  In the prior art described in Patent Document 2, the valve body is provided with an outflow chamber below the valve seat and a longitudinal conduction hole communicating with the outflow chamber, and the outflow chamber and the conduction hole are provided by the outflow chamber and the conduction hole. A pressure equalizing passage connecting the valve port and the back pressure chamber is configured. Therefore, although the problem as in the prior art described in Patent Document 1 does not occur, it is necessary to form a plurality of holes (passages) in different directions with respect to the valve body, and processing of the pressure equalizing passage is still There is a problem that it becomes complicated.

  The present invention has been made in view of the above circumstances, and the object of the present invention is to relatively easily make a pressure equalizing passage communicating the valve port and the back pressure chamber without being restricted by the tip shape of the valve body. It is an object of the present invention to provide a flow control valve which can be formed to reduce the processing cost and the manufacturing cost.

  In order to achieve the above object, the flow control valve according to the present invention basically comprises a valve chamber, an inlet and an outlet, and a valve-seated valve opening between the valve chamber and the outlet. A valve body having a base member provided with an outer cylinder member disposed outside the base member, a valve body inserted through the base member to open and close the valve port, and the valve body The pressure equalizing passage includes a lift drive device for moving in a valve port opening / closing direction, a back pressure chamber formed on the back surface of the valve body, and a pressure equalizing passage communicating the valve port and the back pressure chamber. The pressure passage includes a through hole formed in the base member so as to open to the valve port, and a communication space formed between the base member and the outer cylindrical member and connected to the through hole. It is characterized by being configured.

  In a preferred aspect, the valve port has a valve port portion formed of a cylindrical portion and a truncated cone portion connected to the cylindrical portion, one end of the through hole is opened to the cylindrical portion, and the other end is It is opened in the communication space.

  In a further preferred aspect, the valve port has a plurality of valve ports each including a cylindrical portion and a truncated conical portion connected thereto, and the diameter of the cylindrical portion of each of the valve ports is separated from the valve chamber One end side of the through hole is opened to a cylindrical portion closest to the valve seat among a plurality of cylindrical portions constituting the valve port.

  In another preferred embodiment, the through hole is formed of a lateral hole formed in a direction perpendicular to the elevating direction.

  In another preferred aspect, the communication space is provided on part or all of the outer periphery of the base member.

  In another preferable aspect, a guide member defining the valve chamber is fixed to the base member, and the valve body is inserted into the guide member with the seal member interposed therebetween.

  In another preferred embodiment, the ratio of the opening area of the through hole to the opening area of the valve port is in the range of 0.004 to 0.25.

  The valve body has a curved surface portion designed to obtain equal percentage characteristics or characteristics close thereto as flow characteristics.

  In the flow control valve according to the present invention, the valve port and the back pressure chamber are formed between the base member and the outer cylindrical member, and the through hole formed linearly in the base member so as to open to the valve port. The pressure equalizing passage including the communication space connected to the through hole is communicated with the pressure equalizing passage, so that the pressure equalizing passage communicating the valve port with the back pressure chamber is relatively easy without being restricted by the tip shape of the valve body. It is possible to reduce the processing cost and the manufacturing cost.

  Further, the valve port is formed by a multi-stage valve port, and one end side of the through hole is opened to the cylindrical portion in the valve port which is a region having little vortices and cavitation due to the pressure fluctuation and the refrigerant peeling phenomenon. Noise at the time of fluid (refrigerant) passage can be effectively suppressed.

The longitudinal cross-sectional view which shows the valve closing state of one Embodiment of the flow control valve (motor-operated valve) which concerns on this invention. BRIEF DESCRIPTION OF THE DRAWINGS The longitudinal cross-sectional view which shows the valve open state of one Embodiment of the flow control valve (motor-operated valve) which concerns on this invention. FIG. 2 is a cross-sectional view taken along the line U-U in FIG. The longitudinal cross-sectional view which shows the other example (the 1) of the motor-operated valve shown by FIG. The longitudinal cross-sectional view which shows the other example (the 2) of the electrically driven valve shown by FIG. FIG. 6 is a cross-sectional view taken along line V-V in FIG. 5. Sectional drawing according to the VV arrow line of FIG. 5 which shows the other example (the 3) of the electrically driven valve shown by FIG. Sectional drawing according to the VV arrow line of FIG. 5 which shows the other example (the 4) of the motor-operated valve shown by FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG.1 and FIG.2 is a longitudinal cross-sectional view which shows one Embodiment of the motor-operated valve as a flow control valve based on this invention, FIG. 3: is sectional drawing according to the UU arrow line of FIG.

  In the present specification, descriptions representing positions, directions such as top, bottom, left, right, front, back, etc. are provided for convenience according to the drawings in order to avoid complicated explanation, and the positions, directions in the actual use state Does not necessarily mean

  Further, in each drawing, the gap formed between the members, the separation distance between the members, and the like are large in comparison with the dimensions of the respective constituent members in order to facilitate understanding of the invention and for convenience in drawing. Or it may be drawn small.

  The flow control valve 1 of the illustrated embodiment is, for example, a motor-operated valve used to adjust the flow rate of the refrigerant in a refrigeration cycle or the like, and has a bottomed cylindrical valve body 10 with an open upper surface, and the valve body 10 A can 45 whose lower end is hermetically joined to the outer periphery of the upper end face of the cylindrical member 5), and a wedge-like circle fixed to the inner periphery of the upper end face of the valve body 10 (outer cylindrical member 5 of the valve body 10). A guide stem 15 with a plate 18, a valve stem 21 in which an external thread 21e formed on the outer periphery of its shaft 21a is screwed to an internal thread 15i formed on the small diameter upper portion 15b of the guide stem 15. A rotor 30 is integrally fixed to a shaft 21 so as to be rotatable integrally, and a stator 50 is fitted around the outer periphery of the can 45 so as to rotationally drive the rotor 30.

  Here, a stepping motor is constituted by the rotor 30 and the stator 50, and a screw feeding mechanism is constituted by the female screw portion 15i of the guide stem 15 and the male screw portion 21e of the valve shaft 21; An elevation drive is provided to raise and lower the valve shaft 21 while rotating it.

  In the present embodiment, the valve body 10 has a cylindrical base member 9 with a bottom, and an outer cylinder member 5 disposed outside the base member 9 and made of, for example, a metal. At the upper opening of the base member 9, a thick cylindrical guide member 8 having a valve body guide hole 8a formed at the center, through which a body portion 25b of the valve body 25 to be described later is inserted, is fitted and fixed (illustrated example In this case, a valve chamber 12 consisting of a cylindrical space is defined inside the base member 9 by caulking and fixing by the caulking portion 9a. Further, a valve port 11b with a valve seat 11a is formed in the bottom portion 9b of the base member 9 (vertically).

  The shape of the valve port 11b is not limited to the illustrated example, but in this example, a cylindrical portion (also referred to as a straight portion) formed of a cylindrical surface along the direction of the axis O (raising and lowering direction) And a plurality of stages of valve ports each including a section and the diameter (the diameter of the cylindrical portion of the valve port) is gradually increased in a plurality of stages (three stages in the illustrated example) as being away from the valve chamber 12 It is formed by a multistage valve opening (for example, refer also to the above-mentioned patent documents 3).

  A first inlet / outlet 6 consisting of a pipe joint is joined to one side of the valve chamber 12 of the base member 9 by brazing or the like, and (a lower side of the valve port 11b of) the bottom 9b of the base member 9 A second inlet / outlet 7 consisting of a pipe joint is joined by brazing or the like.

  On the other hand, the outer cylindrical member 5 is formed to have a diameter slightly larger than that of the cylindrical portion 9 c of the base member 9. The lower half of the bottom 9b of the base member 9 has a slightly larger diameter, and the lower end of the outer cylindrical member 5 is joined by butt welding or the like to a collar 9d provided on the outer periphery of the large diameter Thus, the outer cylindrical member 5 is fixedly arranged on the outer periphery of the base member 9 (that is, the outer periphery of the valve chamber 12) with a slight gap (cylindrical gap). The lower portion of the guide stem 15 is inserted into the upper portion of the outer cylindrical member 5.

  Further, in the present embodiment, a through hole 9e is provided which is a horizontal hole penetrating the upper half of the bottom 9b of the base member 9 in the lateral direction (vertical direction to the axis O direction). The through hole 9e is opened in the cylindrical portion (in particular, the cylindrical portion closest to the valve seat 11a (that is, the cylindrical portion directly below the valve seat 11a) of which the inner end side constitutes the valve port 11b). The outer end side is opened to a communication space 4 formed of a gap formed between the base member 9 and the outer cylindrical member 5.

The size and cross-sectional shape of the through hole 9e are not limited to the illustrated example, but for example, the relationship between the minimum diameter φD of the valve port 11b and the diameter φd of the through hole 9e is d ² / D ² = 0.004. If the ratio of the cross sectional area (opening area) of the through hole 9e to the cross sectional area (opening area) of the valve port 11b is within the range of 0.004 to 0.25, the size of the through hole 9e is suppressed. There is an advantage that the through hole 9 e can be easily set in the vicinity (directly below) of the valve seat 11 a.

  The valve shaft 21 has an upper small diameter portion 21b on which the connecting member 32 of the rotor 30 is fitted, a shaft portion 21a having an external thread 21e screwed to the internal thread 15i of the guide stem 15, and the shaft It has a lower connecting portion 21c with a hooked portion 21d and a caulking portion 21f on the lower side than 21a (male screw portion 21e). The lower end portion of the valve stem 21 has its ceiling hole portion connected and fixed to the caulking portion 21f, and is cylindrical with a ceiling portion 23b slidably inserted in the large diameter cylindrical body portion 15a of the guide stem 15. The upper portion of the valve body 25 is slidably inserted in the vertical direction (the raising and lowering direction) in the lower portion of the cylindrical portion 23a of the valve holder 23.

  In the present example, the valve body 25 is made of, for example, a metal and used as a raw material of a stepped axial solid member disposed along the vertical direction (direction of the axis O), and the valve seat 11a having an inverted truncated conical surface portion (Valve port 11b) A valve body 25a whose lower part is inserted and seated, a cylindrical body 25b connected to the upper part of the valve body 25a, a small diameter upper part 25c connected to the upper part of the body 25b, The upper portion of the small diameter upper portion 25c has a thick-walled and fixed outer periphery of the retaining sleeve 25d which is externally fitted and fixed by press-fitting, welding or the like. The small diameter upper portion 25c is inserted into the through hole 27a of the bottom plate portion 27 fixed to the lower end portion of the valve holder 23 (with a slight gap), and (the upper portion of the body portion 25b is the base body The valve body guide hole 8 a of the guide member 8 fixed to the member 9 is slidably inserted. In this example, as a seal member between the body 25b of the valve body 25 and the valve body guide hole 8a of the guide member 8 (specifically, an annular groove provided in the valve body guide hole 8a) A ring made of Teflon (registered trademark) or the like is mounted on the inside of the O-ring 8b in order to reduce the sliding resistance of the valve body 25 with respect to (the valve body guide hole 8a of) the guide member 8 while the O-ring 8b is attached. Shaped packing (also referred to as a cap seal) 8c is mounted.

  Although the tip shape of the valve body 25 (that is, the shape of the valve body 25a) is not limited to the illustrated example, the valve body 25 is made of a solid member, so for example, in the valve seat 11a It is possible to have a seating surface portion to be seated, and a curved surface portion connected to the lower side of the seating surface portion and designed to obtain equal percent characteristics or characteristics approximate thereto as flow characteristics. As a curved surface portion that changes the flow rate of the fluid flowing through the valve port 11b according to such lift amount, an oval spherical surface portion, or a plurality of steps whose curvature or control angle increases continuously or stepwise as the tip approaches the tip The conical tapered surface portion or the like can be configured (see also, for example, Patent Document 3 above).

  At the lower end portion of the valve holder 23, the valve body 25 (the retaining sleeve 25d thereof) is retained and held with the washer 29 formed of a thin annular disc interposed therebetween, and the through hole 27a is provided. A bottom plate portion 27 made of a thick plate is held and fixed by caulking, welding or the like.

  On the other hand, a spring receiving member 26 having a hat-shaped cross-sectional outer shape is placed on the upper surface of the valve body 25, and the valve body is pressed between the flange 26 a of the spring receiving member 26 and the ceiling 23 b of the valve holder 23. A valve body biasing spring 24 consisting of a cylindrical compression coil spring for shock absorption and compression is compressed, and the valve body 25 is always directed downward (valve closing direction) by (the biasing force of) the valve body biasing spring 24. It is powered.

  Further, the inside and the outside of the valve holder 23 (that is, the communication space 4 between the base member 9 and the outer cylinder member 5) are the large diameter cylindrical body portion 15a of the guide stem 15 and the cylindrical portion 23a of the valve holder 23. And the back pressure chamber 20 formed on the upper side (rear surface) of the valve body 25 and the valve port 11b, and the communication hole formed in the base member 9 9e, the communication space 4 and the sliding surface gap 28 are always in communication through the pressure equalizing passage 3.

  The valve body 25 and the valve body urging spring 24 held by the valve shaft 21, the valve holder 23, the valve shaft 21 and the valve holder 23 relatively movable and relatively rotatable in the vertical direction (raising and lowering direction) In the state where the body 25 is separated from the valve seat 11a (the valve open state), the body 25 is raised and lowered while rotating substantially integrally.

  Further, in order to set the origin position of the rotor 30 and the valve shaft 21, on the upper surface of the small diameter upper portion 15b of the guide stem 15, a valve closing direction fixing stopper 55 having a rectangular cross section having a predetermined width, height and depth is directed upward. A valve opening direction fixing stopper 56 having a rectangular cross section having a predetermined width, height, and depth is provided to project downward from the upper portion of the large diameter cylindrical body portion 15a of the guide stem 15.

  A valve closing direction movable stopper 35 is screwed onto the upper end portion of the male screw portion 21 e of the valve shaft 21 and retained in a disc-like ceiling portion of the rotor 30 so as to be retained. The valve-closing direction movable stopper 35 has a nut portion 35a whose outer shape in plan view is a hexagon and one side of which is arc-shaped when screwed with the male screw portion 21e, and a predetermined width projecting downward from the nut portion 35a. And a stopper portion 35s having a rectangular cross section having a height and a depth.

  Further, at the lower end portion of the male screw portion 21 e of the valve shaft 21, a valve opening movable stopper 36 which is held in contact with and held by the valve opening fixed stopper 56 is screwed to the ceiling of the valve holder 23. It is retained and locked to 23b. The valve opening direction movable stopper 36 has a nut portion 36a screwed to the male screw portion 21e and a stopper portion 36s having a rectangular cross section having a predetermined width, height, and depth and projecting upward from the nut portion 36a. It has become.

  The rotor 30 is composed of a cylindrical magnet 31 with a ceiling and a connector 32 integrally coupled to the ceiling. The connector 32 is externally fitted to the upper small diameter portion 21 b of the valve shaft 21 and is closed. It is placed on the valve direction movable stopper 35 and welded and fixed to the upper small diameter portion 21b.

  Here, on the lower surface side of the ceiling portion of the rotor 30, a recessed portion 33 provided with a D cut portion whose both ends are formed in a D shape in plan view is provided, and the D cut portion formed in the recessed portion 33 The arc-shaped side of the nut portion 35a of the movable valve closing direction stopper 35 is fitted into a portion other than the arc-shaped portion, and the other two sides of the nut portion 35a are inserted into the D-cut portion. Are fitted in contact with each other, whereby the rotor 30, the valve closing direction movable stopper 35, and the valve shaft 21 are raised and lowered while integrally rotating.

  On the other hand, on the outer periphery of the can 45, a stator 50 composed of a yoke 51, a bobbin 52, a coil 53, a resin mold 54 and the like is externally fitted. The stator 50 is positioned and fixed at a predetermined position with respect to the valve main body 10 by a positioning fixture (not shown) provided at the bottom of the stator 50.

  Thus, when the rotor 30 is rotated, the valve shaft 21 is rotated integrally with it. At this time, the valve holder 23 is moved up and down with the valve body 25 together with the valve shaft 21 by the screw feed mechanism. , And the passing flow rate of the refrigerant is adjusted.

  Specifically, the movable stopper 35 is held in contact with the fixed stopper 55 and locked, the rotor 30 and the valve shaft 21 are at the lowest position, and the valve biasing spring 24 (biasing force) When a pulse serving as a valve opening direction drive pattern is supplied to the stator 50 from a state in which the valve body 25a) is seated on the valve seat 11a and the valve port 11b is closed (the closed state shown in FIG. 1) 30 and the valve shaft 21 are rotated, and the rotor 30, the valve shaft 21, the valve holder 23, and the valve opening direction movable stopper 36 are raised while rotating by the screw feed mechanism consisting of the female screw portion 15i and the male screw portion 21e. Along with this, while the pressing force against the valve body 25 is weakened, the valve body biasing spring 24 expands and returns to the original set state, and thereafter (the valve body portion 25a of the valve body 25 separates from the valve seat 11a) The valve port 11b is opened (the open state shown in FIG. 2). In this case, the lift amount (valve opening degree = flow rate) of the valve 25 is determined according to the number of pulses supplied to the stator 50, and when the pulse supply is further continued, finally, the movable stopper 36 is for the valve opening direction. The fixed stopper 56 is held in contact with the fixed stopper 56 to forcibly stop the rotation and lifting of the rotor 30, the valve shaft 21 and the valve holder 23.

  In the flow control valve (motor-operated valve) 1 of the present embodiment, the fluid (refrigerant) is bidirectional (in the direction from the first inlet / outlet 6 toward the second inlet / outlet 7 (horizontal → lower)) and from the second inlet / outlet 7 It is made to flow in the direction (down → sideways) toward the first inlet / outlet 6, but the back pressure chamber 20 above and below the valve body 25, that is, the valve port 11 b and the upper side of the valve body 25. Is constantly communicated via the pressure equalizing passage 3 (lateral hole 9e, communication space 4, sliding surface gap 28 etc.), for example, the first inlet / outlet 6 as the inlet (high pressure side), the second inlet / outlet In the case of a horizontal → downward flow with 7 as the outlet (low pressure side), the depression force (force acting in the valve closing direction) acting on the valve body 25 and the lifting force (force acting in the valve opening direction) are balanced (difference) Pressure will be canceled).

  As described above, in the flow control valve (motor-operated valve) 1 of the present embodiment, the valve port 11b and the back pressure chamber 20 are linearly formed on the base member 9 so as to open to the valve port 11b (in other words, The pressure equalizing passage 3 includes the through hole 9e formed in one direction and the communication space 4 formed between the base member 9 and the outer cylindrical member 5 and connected to the through hole 9e. The pressure equalizing passage 3 for communicating the valve port 11b with the back pressure chamber 20 can be relatively easily formed without restriction of the tip shape of the valve body 25, thereby suppressing the processing cost and the manufacturing cost. it can.

  Further, the valve port 11b is formed as a multi-stage valve port, and one end side of the through hole 9e is opened to the cylindrical portion in the valve port 11b which is a region having little vortices and cavitation accompanying pressure fluctuation and refrigerant peeling phenomenon. Therefore, noise at the time of fluid (refrigerant) passage can be effectively suppressed. Even when the through hole 9e is connected to a valve port having one valve port formed of a cylindrical portion and a truncated conical portion connected thereto, one end side of the through hole 9e is formed in the cylindrical portion. Noise can be reduced. Further, the frusto-conical portion is not limited to the frusto-conical shape, and the cross-sectional shape including the axis may have a curved shape.

  In the above embodiment, the O-ring 8b and the packing 8c between the body 25b of the valve body 25 and the valve body guide hole 8a of the guide member 8 are mounted in the annular groove provided in the valve body guide hole 8a. However, for example, as shown in FIG. 4, the O-ring 8b and the packing 8c may be mounted in an annular groove provided on the outer periphery of the body 25b of the valve body 25. In this case, a ring-shaped packing 8c is attached to the outside of the O-ring 8b as a sealing member.

  In the above embodiment, the entire outer periphery of the base member 9 (valve chamber 12) is the communication space (cylindrical gap) 4 that constitutes the pressure equalizing passage 3. However, the outer periphery of the base member 9 (valve chamber 12) A portion of the space may be the communication space 4. For example, as shown in FIGS. 5 and 6, a D-cut surface 9f is formed at a predetermined position on the outer periphery of the base member 9 (the opposite side to the first entry / exit 6 in the illustrated example). The communication space 4 may be a gap formed with the cylindrical member 5. Further, as shown in FIG. 7, the outer periphery of the base member 9 is formed in a polygonal shape (viewed in the direction of the axis O), and between the outer periphery of the base member 9 and the inner periphery (cylindrical surface) of the outer cylindrical member 5. The gap formed in the above may be the communication space 4. Further, as shown in FIG. 8, the inner periphery (inner wall) of the outer cylinder member 5 is formed in a polygonal shape (viewed in the direction of the axis O), and the outer periphery (cylindrical surface) of the base member 9 and the outer cylinder member 5 are The gap formed between the inner circumference and the inner circumference may be the communication space 4.

  Further, according to the present invention, an electric motor is used to adjust a lift amount (valve opening degree) arbitrarily and finely by moving up and down (moving) a valve shaft using a stepping motor having a stator and a rotor as described in the above embodiments. It goes without saying that the present invention can also be applied to an electromagnetic flow control (switching) valve that raises and lowers a valve body using, for example, a solenoid or the like in addition to the flow control valve of the formula.

1 Flow control valve (motor operated valve)
3 pressure equalizing passage 4 communication space 5 outer cylinder member 6 first inlet / outlet (inlet)
7 2nd entry and exit (outlet)
8 guide member 9 base member 9e through hole 9f D cut surface 10 valve main body 11a valve seat 11b valve port 12 valve chamber 15 guide stem 15i female threaded portion 20 back pressure chamber 21 valve shaft 21e male threaded portion 23 valve holder 24 valve body biasing spring 25 valve body 25a valve body portion 26 spring support member 27 bottom plate portion 27a through hole 28 sliding surface clearance 29 washer 30 rotor 35 movable stopper for valve closing direction 36 movable stopper for valve opening direction 45 can 50 stator 55 fixed for valve closing direction Stopper 56 Fixed stopper for valve opening direction

Claims (8)

A base member having a valve chamber, an inlet, and an outlet, and a valve-seated valve port between the valve chamber and the outlet, and an outer cylindrical member disposed outside the base member The valve body to be
A valve body inserted through the base member for opening and closing the valve port;
An elevation drive device for moving the valve body in a valve opening and closing direction;
A back pressure chamber formed on the back of the valve body;
And a pressure equalizing passage communicating the valve port with the back pressure chamber.
The pressure equalizing passage is a through hole formed in the base member so as to open to the valve port, and a communication space formed between the base member and the outer cylindrical member and connected to the through hole. The flow control valve characterized by including.   The valve port has a valve port portion formed of a cylindrical portion and a truncated conical portion connected thereto, and one end of the through hole is opened to the cylindrical portion and the other end is open to the communication space The flow control valve according to claim 1, characterized in that it is operated. The valve port has a plurality of valve ports each consisting of a cylindrical portion and a truncated conical portion connected to the cylindrical portion, and the diameter of the cylindrical portion of each of the valve ports is sequentially increased as it is separated from the valve chamber It is a multistage valve port,
The flow control valve according to claim 2, wherein the through hole has one end side opened to a cylindrical portion closest to the valve seat among a plurality of cylindrical portions constituting the valve port. .   The flow control valve according to any one of claims 1 to 3, wherein the through hole is formed of a horizontal hole formed in a direction perpendicular to the elevating direction.   The flow control valve according to any one of claims 1 to 4, wherein the communication space is provided on a part or all of the outer periphery of the base member.   A guide member defining the valve chamber is fixed to the base member, and the valve body is inserted through the seal member with the seal member interposed therebetween. The flow control valve according to any one of the preceding claims.   The flow control valve according to any one of claims 1 to 6, wherein a ratio of an opening area of the through hole to an opening area of the valve port is in a range of 0.004 to 0.25.   The flow control valve according to any one of claims 1 to 7, wherein the valve body has a curved surface portion designed to obtain equal percent characteristics or characteristics approximate thereto as the flow characteristics.

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