JP4416528B2 - Flow control valve - Google Patents

Description

The present invention relates to a flow control valve for refrigerant used in a refrigeration cycle such as an air conditioner or a refrigeration apparatus.

Air conditioner, refrigerator or the like flow control valves used built in controls the flow amount of fluid such as refrigerant is a device for controlling the expansion amount of the refrigerant, normally the valve chamber and the valve seat And a bottomed cylindrical can fixed to the upper portion of the valve body. A rotor is built inside the can, and an insertion hole is formed in the center of the can outside. The stator which has is fitted.

FIG. 4 is a longitudinal sectional view of the known expansion valve disclosed in the following Patent Document 1, and this technique will be described first.
The valve body 2 constituting the expansion valve 1 includes a valve chamber 2c, a guide bush fixing portion 2d, and a can fixing portion 2e. A fluid inflow pipe 2a through which fluid such as a refrigerant enters and exits and a fluid outflow into the valve chamber 2c. A pipe 2b is provided, and a valve seat 2f to which a needle valve, which is a valve body 3a formed at the tip of the valve shaft 3, contacts and separates is disposed.

  The guide bush fixing portion 2d is located above the valve chamber, and fixes the valve body 2 and the guide bush 4. Further, a female screw portion 4a is formed on the inner periphery of the guide bush 4, and the female screw The part 4a is screwed with a male screw part 5a formed on the outer periphery of the valve shaft holder 5, and the female screw part and the male screw part constitute a screw feed mechanism. And in this valve-shaft holder 5, the valve shaft 3 which forms the valve body 3a in the lower end part is inserted so that sliding is possible, and this valve-shaft 3 is shrink | fitted in the valve-shaft holder 5. It is always urged downward by the compression coil spring 3b.

  The can fixing portion 2e is located at the upper end of the valve body 2 and is composed of a ring-shaped metal plate whose inner peripheral surface is fixed by caulking and whose lower end surface is joined by welding. The can 6 is fixed to the valve body 2 by welding to the valve body. The valve shaft 3 and the rotor 7 are coupled to each other by fitting a sleeve 5d integrally formed with the valve shaft holder 5 on the valve shaft 3 and fitting the sleeve 5d on the rotor 7 with a permanent magnet. . A push nut 3 c is press-fitted and fixed to the upper end of the valve shaft 3, and its flange portion is coupled to the rotor 7 while allowing the valve shaft 3 to move slightly up and down. The upper limit of the upward movement of the valve shaft 3 and the rotor 7 is performed by contact between a spring 7 b provided on the upper portion of the rotor 7 and the inner surface of the can 6. The lower stopper 4b fixed to the valve shaft holder 5 and the upper stopper 5b formed on the sleeve 5d constitute a stopper mechanism.

  A rotor 7 is built in the can 6, and a stator 8 is fitted on the outside of the can 6. A stator coil 8 a and a yoke 8 b are stored in the stator 8 in the vertical direction, and the stator coil 8 a is energized through a lead wire 8 c and a connector 8 d provided on the outer periphery of the stator 8. The yoke 8b is excited by energization of the stator coil 8a to rotate the rotor 7, and the valve body 3a is opened and closed by sliding the valve shaft holder 5 and the valve shaft 3 by a screw feed mechanism to control the refrigerant flow rate. ing. A connector cover 8 e is bonded to the stator 8.

  A metal ring-shaped mounting plate 9 is fixed below the stator 8, and an anti-rotation piece 9 a formed integrally with the mounting plate 9 is engaged with a fluid inflow pipe 2 a that protrudes horizontally from the valve body 2. The engagement hole 9b is engaged with one side of the ring-shaped welded portion between the valve body 2 and the can 6 and a pressing piece 9c formed integrally with the mounting plate 9 is pressed on the other side of the ring-shaped welded portion. Thus, the stator 8 is fixed.

JP 2001-50415 A

  However, the expansion valve according to the prior art requires a large opening and closing force for opening and closing the valve body, and therefore, there is a problem that a large valve body driving unit composed of a stator or the like is required. It has been difficult to satisfy both accurate flow control in a low flow rate region and flow control in a large flow rate region.

Therefore, the present invention has been made in view of such problems, and the object of the present invention is to reduce the overall shape and to accurately control the degree of opening and closing of the main valve, and to accurately control in a small flow rate region. An object of the present invention is to provide a flow rate control valve that can easily control the flow rate and can control a refrigerant at a large flow rate.

In order to achieve the above object, a flow control valve according to claim 1 of the present invention includes a main valve main body and a sub valve main body provided integrally with the main valve main body, and the main valve main body includes: A main valve chamber, a fluid inflow pipe communicating with the main valve chamber, a main valve seat formed in the main valve chamber, and a fluid outflow pipe communicating with the main valve chamber via an opening of the main valve seat; , disposed in said main valve chamber, the opening closing direction by the force based on the differential pressure between the fluid outlet tube and the fluid inlet tube as well as opening and closing the opening of the main valve seat away against the main valve seat A main valve body that is urged, and the sub-valve body communicates with the main valve chamber through a gap formed between the main valve body and the main valve body, and the sub-valve body A sub-valve seat provided at a communication portion with the fluid outflow pipe in the valve chamber, a sub-valve body for opening and closing the opening of the sub-valve seat, and driving the sub-valve body The sub-valve seat has a small opening degree and the differential pressure between the fluid inflow pipe and the fluid outflow pipe is not less than a predetermined value. The main valve body is closed by a force based on pressure, and the refrigerant in the main valve chamber is supplied to the fluid outlet pipe through the sub valve chamber and the sub valve seat, and the sub valve body opens the sub valve seat. When the pressure increases and the differential pressure becomes less than a predetermined value, the main valve body is opened by a force based on the pressure of the refrigerant from the fluid inflow pipe, and the refrigerant in the main valve chamber passes through the main valve seat. It is supplied to a fluid outflow pipe.

Flow control valve according to claim 2, wherein, in the expansion valve according to claim 1, wherein said drive unit is a stepping motor, the rotation of the rotor of the stepping motor to the contact and separation operation to the sub valve seat of said sub-valve body And a screw feed mechanism for conversion .

Flow control valve according to claim 3, wherein, in claim 1 or claim 2 Symbol placement of the expansion valve includes a guided portion that the main valve body protrudes toward the auxiliary valve body, the sub-valve body Has a guide portion that slidably guides the guided portion in the opening and closing direction of the main valve body .

The flow control valve of the present invention has the above configuration, when the opening degree of the sub valve seat by the sub valve body driven by the drive unit is small, and the differential pressure between the fluid inflow pipe and the fluid outflow pipe is a predetermined value or more. In this case, the main valve body is kept closed unless the refrigerant pressure on the inflow side becomes excessive, and during this period, the opening degree of the sub-valve body is controlled by a small drive unit consisting of an electric part or an electromagnetic part, and in a small flow rate region. Realize accurate flow rate control. When the differential pressure by opening degree is increased sub valve seat by the sub-valve body is less than a predetermined value, the force to thus main valve body based on the pressure of the refrigerant from the fluid inlet pipe is driven by a drive unit Open at once. The sub-valve element that is driven by the drive unit to open and close the opening of the sub-valve seat is constantly exposed to the pressure on the fluid outflow pipe side and is not exposed to the differential pressure from the pressure on the fluid inflow pipe side. The opening degree can be stably controlled regardless of the differential pressure. In this way, even when the inflow-side refrigerant suddenly rises (shock high pressure) during low opening control (when controlling the subvalve only), the main valve body opens and the shock high pressure is reduced. Since it can escape to the side, damage to the cycle can be avoided. Further, by providing the guide portion and the guided portion, it is possible to prevent the main valve body from being shaken with a simple configuration.

Hereinafter, embodiments of a flow control valve according to the present invention will be described with reference to the drawings. 1 is a longitudinal sectional view showing a closed state of a flow control valve according to an embodiment of the present invention, FIG. 2 is a longitudinal sectional view showing an intermediate stage of opening and closing of the flow control valve , and FIG. 3 is an opened state of the flow control valve . FIG.

The flow control valve 10 of the embodiment is used as an expansion valve . As shown in FIG. 1, the flow rate of refrigerant is controlled by a main valve body 63 that contacts and separates from a main valve seat 62 in the main valve chamber 61. A main valve main body 60, a can 40 that is fixed to the sub valve main body 20 that is integral with the main valve main body 60 and operates the sub valve body 23, and a stator that is externally fitted to the can 40 and rotationally drives the rotor 30. 50 and an auxiliary valve body 23 that controls the degree of opening and closing of the main valve body 63 by contacting and separating from the auxiliary valve seat 22 in the auxiliary valve chamber 21 as a pilot valve of the main valve body 60. Increase / decrease of the opening degree of the main valve body 63 is performed by increase / decrease of the back pressure of the main valve body 63 by the sub valve body 23. The rotor 30 and the stator 50 constitute a stepping motor.

  The can 40 has a bottomed cylindrical shape formed of a nonmagnetic metal such as stainless steel, and is fixed to a stainless steel flange 41 fixed to the upper part of the sub-valve body 20 by welding or the like. It is kept airtight. The stator 50 is composed of a yoke 51 made of a magnetic material and upper and lower stator coils 53 wound around the yoke 51 via a bobbin 52, and a fitting hole 50 a that fits outside the can 40 is formed. Yes. The stator 50 has a fitting hole 50a having a lower surface opening at the center, and the can 40 is fitted into the fitting hole and fixed to the can 40.

  A plurality of lead terminals 54 connected to the stator coil 53 protrude from the stator 50, and a connector 56 to which a plurality of lead wires 55 are connected is connected to the lead terminals. A cover 57 covering the connector 56 is welded to the stator 50, and the inside of the cover 57 is filled with a filler 58 such as silicone resin or epoxy resin.

  The sub valve body 23 is formed at the lower end of a brass valve shaft 24. A drive mechanism that contacts and separates the sub-valve body 23 from the sub-valve seat 22 extends from the sub-valve body 20 toward the rotor 30 and is fixed, and a cylindrical guide bush 26 in which a fixing screw portion 25 is formed, and the guide This is a screw feed mechanism including a valve shaft holder 32 having a moving screw portion 31 that is screwed into the fixing screw portion 25 of the bush 26, and the screw feed mechanism is disposed at a substantially central portion of the axial length in the rotor 30. is doing.

The fixed screw portion 25 is formed of a male screw on the outer periphery of the guide bush 26, the moving screw portion 31 is formed of a female screw on the inner periphery of the valve shaft holder 32, and both the guide bush 26 and the valve shaft holder 32 are made of brass. It is formed from a cylindrical material.
The valve shaft holder 32 has a cylindrical shape with a lower opening located outside the guide bush 26. As described above, the moving screw portion 31 is formed on the inner surface, and the valve shaft holder 32 has the valve shaft 24 at the center thereof. The upper reduced diameter portion is fitted and connected by a push nut 33. The valve shaft 24 formed with the sub-valve body 23 at the lower end is fitted into the center of the valve shaft holder 32 so as to be movable up and down, and is always attached to the lower side by a compression coil spring 34 that is compressed in the valve shaft holder 32. It is energized. On the side surface of the guide bush 26, a pressure equalizing hole 32a for equalizing the pressure in the auxiliary valve chamber 21 and the can 40 is formed.

  A return spring 35 composed of a cylindrical compression coil spring is attached to the outer periphery of a push nut 33 that is press-fitted and fixed to the upper end of the valve shaft 24, and a fixed screw portion 25 of the guide bush 26 and a moving screw portion 31 of the valve shaft holder 32. When the screw is disengaged, the return spring 35 abuts on the inner surface of the can 40 and urges the screwing of the fixed screw portion 25 and the moving screw portion 31 to return. The return spring 35 may be attached in a state of being loosely fitted and placed on the outer periphery of the push nut 33, or may be attached so as to be elastically contacted with the outer periphery of the push nut 33.

  The joint of the sub-valve main body 20 and the can 40 is performed by butt welding the end of the can to the stepped portion of the bowl-like plate 41 fixed to the sub-valve main body 20 by welding or the like. A guide bush 26 is connected and fixed to the upper part of the sub valve body 20, a sub valve chamber 21 is formed in the lower part thereof, and the lower part of the valve shaft 24 is arranged in the sub valve chamber 21. Further, the bottom of the auxiliary valve chamber 21 constitutes an auxiliary valve seat 22. In addition, a male screw portion 20a is formed on the outer periphery of the lower portion of the auxiliary valve body 20, and a lower portion of the auxiliary valve body 20 extends downward to form a guide portion 20b. The space outside the guide portion 20b (the upper main valve chamber 61a, which will be described later) and the sub valve chamber 21 are communicated with each other through a communication inflow hole 21a. The lower auxiliary valve chamber 21b communicates with a communication outflow hole 60d described later.

  The valve shaft holder 32 and the rotor 30 are coupled via a support ring 36, and the support ring 36 is constituted by a brass metal ring inserted when the rotor 30 is formed. Then, the upper protrusion of the valve shaft holder 32 is fitted into the inner peripheral hole portion of the support ring 36, and the rotor 30, the support ring 36 and the valve shaft holder 32 are joined by caulking and fixing the outer periphery of the protrusion.

  A lower stopper body (fixed stopper) 27 constituting one of the stopper mechanisms is fixed to the guide bush 26. The lower stopper body 27 is made of a ring-shaped plastic, and a plate-like lower stopper is disposed above the lower stopper body 27. A piece 27a is projected. Further, an upper stopper body (moving stopper) 37 constituting the other of the stopper mechanism is fixed to the valve shaft holder 32, and the upper stopper body 37 is also made of a ring-shaped plastic and has a plate-like upper side facing downward. A stopper piece 37a is protruded and can be engaged with the lower stopper piece 27a.

  The lower stopper body 27 is fixed to the spiral groove portion 26a formed on the outer periphery of the guide bush 26 by injection molding, and the upper stopper body 37 is fixed to the spiral groove portion 32b formed on the outer periphery of the valve shaft holder 32 by injection molding. ing.

The main valve body 60 is formed in a substantially cylindrical shape, and an upper portion thereof is provided with a mounting recess 60g for mounting the sub-valve main body 20, and a female screw portion 60c is formed on the inner peripheral surface of the mounting recess 60g. The The upper main valve chamber 61a formed continuously below the mounting recess 60g is provided with a guide portion 20b on the sub-valve main body 20 side, and the main valve chamber 61 is formed further below the guide portion 20b. The An inflow hole 60e is formed in the lower side of the main valve chamber 61, and a lower main valve chamber 61b and an outflow hole 60f communicating with the lower main valve chamber 61b are formed in the lower portion. A fluid inflow pipe 60a is attached to the inflow hole 60e, and a fluid outflow pipe 60b is attached to the outflow hole 60f.
Further, a communication outflow hole 60 d is formed in the main valve body 60 in parallel with the main valve chamber 61. The communication outflow hole 60d allows the lower auxiliary valve chamber 21b and the outflow hole 60f to communicate with each other. Further, a large diameter portion 63b having a uniform diameter is disposed in the main valve body 63 in the main valve chamber 61 with a predetermined gap.

Due to the upward movement of the main valve body 63 in the main valve chamber 61, the amount of refrigerant flowing from the fluid inflow pipe 60a to the fluid outflow pipe 60b can be fully opened within a short time. That is, the main valve body 63 includes a main valve seat abutting portion 63a that is separated from and contacting the main valve seat 62, a large diameter portion 63b, and a guided portion 63d, and a step portion 63f is provided below the large diameter portion 63b. In addition, the outer periphery of the large-diameter portion 63b is formed with the same diameter in the cross section , and further, a communicating hole 63e is formed in the guided portion 63d. The guided portion 63d is slidably disposed on the inner surface of the guide portion 20b. Since the outer periphery of the large-diameter portion 63b has the same cross-sectional diameter, the minute gap between the large-diameter portion 63b and the inner wall 63c of the main valve chamber 61 has the same area in any cross section between the upper and lower positions. The gap forms a flow path from the main valve chamber 61 to the sub valve chamber 21, and the cross-sectional area of the flow path is constant over the entire length of the main valve body in the moving direction.

  Further, a spring chamber (not indicated) is formed in the guided portion 63d, and a coil spring 64 for elastically pressing the main valve body 63 in the closing direction is disposed between the bottom of the spring chamber and the lower surface of the sub-valve main body 20. The The configuration in which the guided portion 63d is guided by the guide portion 20b is not necessarily required, but this configuration can prevent vibration (lateral movement) of the main valve body 63.

Next, the operation of the flow control valve 10 configured as described above will be described.
As shown in FIG. 1, when the valve shaft 24 is at the lowest position, the auxiliary valve body 23 is set to abut on the auxiliary valve seat 22 to be in a “closed” state. In this state, the main valve body 63 is set. Is also “closed”, and the refrigerant is shut off (no flow or expansion). That is, in this state, since the intermediate pressure acting on the main valve body 63 from above (in the closing direction) is equal to the inflow side refrigerant pressure, the differential pressure between the inflow side refrigerant pressure and the outflow side refrigerant pressure and the spring pressure of the coil spring 64 Is closed.

  When the sub-valve body 23 is in a “closed” state and a predetermined current is applied to the stator coil 53 and excited, the rotor 30 and the valve shaft holder 32 rotate with respect to the guide bush 26 fixed to the sub-valve main body 20. The valve shaft holder 32 is moved upward by the screw feed mechanism of the fixed screw portion 25 of the guide bush 26 and the moving screw portion 31 of the valve shaft holder 32, and the sub valve body 23 at the lower end of the valve shaft 24 is moved to the sub valve. The valve port is opened away from the seat 22 and the refrigerant can pass through the valve port. The amount of refrigerant passing can be controlled by the amount of rotation of the rotor 30, and the amount of rotation of the rotor is regulated by the number of pulses, so that accurate control can be performed.

  That is, the flow rate control of the refrigerant is performed according to the opening degree of the sub valve seat contact portion 23a according to the amount of rotation of the rotor. In other words, according to the opening operation (increase) of the auxiliary valve seat contact portion 23a, the amount flowing through the auxiliary valve body 20 increases proportionally, and as a result, the amount flowing through the communication inflow hole 21a increases. The refrigerant pressure in the upper main valve chamber 61a is lowered. However, although the refrigerant pressure in the upper main valve chamber 61a decreases, the main valve body 63 sets the differential pressure between the inflow side refrigerant pressure and the outflow side refrigerant pressure and the setting of the coil spring 64 until the refrigerant pressure becomes a predetermined pressure or less. Therefore, it does not operate in the opening direction.

The opening amount (increase) of the auxiliary valve seat abutting portion 23a becomes equal to or greater than a predetermined value, and the amount flowing through the auxiliary valve body 20 increases. As a result, the amount flowing out from the communication inflow hole 21a increases, and the upper main valve When the refrigerant pressure in the chamber 61a falls below a predetermined level, the main valve body 63 moves in the opening direction all at once.
Further, during this time, even if the refrigerant pressure flowing in from the fluid inflow pipe 60a suddenly increases, the refrigerant pressure acts on the step portion 63f, causing the main valve body 63 to instantaneously move the elastic force of the coil spring 64 and the upper main pressure. By moving up against the force of the refrigerant pressure in the valve chamber 61a, the valve chamber 61a can be "open", and damage to the flow control valve 10 and the refrigeration cycle can be avoided.

  Further, in this embodiment, when the stator coil 53 is energized in the other direction and excited, the rotor 30 and the valve shaft holder 32 are rotated in the opposite direction with respect to the guide bush 26 fixed to the sub-valve main body 20, and the guide bush For example, the valve shaft holder 32 is moved downward and the sub valve body 23 is seated and pressed against the sub valve seat 22 by the screw feed mechanism of the fixed screw portion 25 of 26 and the moving screw portion 31 of the valve shaft holder 32. Is closed.

  At the time when the valve port is closed, the upper stopper body 37 is not yet in contact with the lower stopper body 27, and the rotor 30 and the valve shaft holder 32 are further rotated and lowered while the sub valve body 23 is closed. At this time, since the valve shaft holder 32 is lowered with respect to the valve shaft 24, the downward force of the valve shaft holder 32 is absorbed by the compression coil spring 34 being compressed. Thereafter, when the rotor 30 further rotates and the valve shaft holder 32 descends, the upper stopper piece 37a of the upper stopper body 37 comes into contact with the lower stopper piece 27a of the lower stopper body 27, and even if energization to the stator coil 53 is continued, the valve The lowering of the shaft holder 32 is forcibly stopped.

Since the stopper mechanism composed of the upper stopper body 37 and the lower stopper body 27 is disposed within the entire axial length of the rotor 30, the rotor 30 and the valve shaft holder 32 are not affected even when the stopper mechanism is functioning. The operation is stable with little tilting, and smooth operation is possible even when the rotor 30 is rotated in the reverse direction.
The closing operation of the main valve body 60 is performed by the closing operation of the sub valve seat abutting portion 23a. That is, the amount of flow through the sub-valve main body 20 is reduced according to the amount of closing operation (decrease) of the sub-valve seat abutment portion 23a. The refrigerant pressure of 61a rises, and the main valve body 63 is moved downward, that is, the main valve body 63 is operated in the closing direction.

In the present embodiment, the case where the present invention is used as an expansion valve has been described. However, the present invention is used as a flow control valve for a dry operation using a pipe line between an evaporator and an evaporator provided in a refrigeration cycle. Can also be used. Further, the drive unit may be an electromagnetic valve instead of the electric valve of the embodiment.

The longitudinal cross-sectional view which shows the flow control valve (closed state) of the Example which concerns on this invention. The longitudinal cross-sectional view which shows the middle stage of opening and closing of the flow control valve of the Example. The longitudinal cross-sectional view which shows the flow control valve (open state) of the Example. The longitudinal cross-sectional view of the flow control valve which concerns on a prior art.

Explanation of symbols

1..Expansion valve (known example) 2..Valve body 2a..fluid inflow pipe 2b..fluid outflow pipe 2c..valve chamber 2d..guide bush fixing portion 2e..can fixed portion 2f..valve seat 3.・ ・ Valve shaft 3a ・ ・ Valve 3b ・ ・ Compression coil spring 3c ・ ・ Push nut 4 ・ ・ Guide bush 4a ・ ・ Female thread 4b ・ ・ Lower stopper 5 ・ ・ Valve shaft holder 5a ・ ・ Male thread 5b ・ Upper Stopper 5d ・ ・ Sleeve 6 ・ ・ Can 7 ・ ・ Rotor 7b ・ ・ Spring
8 .. Stator 8a .. Stator coil 8b .. Yoke 8c .. Lead wire 8d .. Connector 8e .. Cover 9 .. Mounting plate 9a .. Anti-rotation piece 9b .. Engagement hole 9c .. Pressing piece

10. Flow control valve (present invention)
20. ・ Sub-valve body 20a ・ ・ Male thread portion 20b ・ ・ Guide portion 21 ・ ・ Sub-valve chamber 21a ・ ・ Communication inflow hole 21b ・ ・ Lower sub-valve chamber 22 ・ ・ Sub-valve seat 23 ・ ・ Sub-valve body 23a ・ ・Sub valve seat abutting part 24..Valve shaft 25..Fixing screw part 26..Guide bush 26a..Helix groove part 27..Lower stopper body (fixing stopper) 27a..Lower stopper piece 30..Rotor 31.・ Moving screw part 32 ・ ・ Valve shaft holder 32 a ・ ・ Equal pressure hole 32 b ・ ・ Spiral groove part 33 ・ ・ Push nut 34 ・ ・ Compression coil spring 35 ・ ・ Return spring 36 ・ ・ Support ring 37 ・ ・ Upper stopper body ( 37a ··· Upper stopper piece 40 · · Can 41 · · Plate 50 · · Stator 50a · · Fitting hole 51 · · yoke 52 · · bobbin 53 · · stator coil 54 · · lead terminal 55 · · · Lead 56. Connector 57. Cover 58. Filler 60. Main valve body 60a. Fluid inflow pipe 60b. Fluid outflow pipe 60c. Female thread 60d. Communication outflow hole 60e. Inflow hole 60f. Outlet hole 60g ・ ・ Mounting recess 61 ・ ・ Main valve chamber 61a ・ ・ Upper main valve chamber 61b ・ ・ Lower main valve chamber 62 ・ ・ Main valve seat 63 ・ ・ Main valve body 63a ・ ・ Main valve seat contact part 63b ・· Large diameter portion 63c · · Inner wall 63d · · Guided portion 63e · · Communication hole 63f · · Stepped portion 64 · · Coil spring

Claims (4)

A main valve body, and a sub-valve body provided integrally with the main valve body,
The main valve body includes a main valve chamber, a fluid inflow pipe communicating with the main valve chamber, a main valve seat formed in the main valve chamber, and an opening in the main valve seat. Based on the pressure difference between the fluid inflow pipe and the fluid outflow pipe, which is disposed in the main valve chamber, opens and closes the opening of the main valve seat and opens and closes the opening of the main valve seat. a main valve body which is biased in the opening closing direction by the force, and
The sub valve body is provided in a communication portion between the sub valve chamber communicating with the main valve chamber through a gap formed between the main valve body and the main valve body, and the fluid outflow pipe in the sub valve chamber. An auxiliary valve seat that opens and closes the opening of the auxiliary valve seat, and a drive unit that drives the auxiliary valve body, and the degree of opening of the auxiliary valve seat by the auxiliary valve body is small When the differential pressure between the fluid inflow pipe and the fluid outflow pipe is equal to or greater than a predetermined value, the main valve body is closed by a force based on the differential pressure, and the refrigerant in the main valve chamber is When the opening degree of the sub valve seat by the sub valve body becomes large and the differential pressure becomes less than a predetermined value, the refrigerant from the fluid inflow pipe is supplied to the fluid outflow pipe via the sub valve seat. The main valve body is opened by a force based on pressure, and the refrigerant in the main valve chamber passes through the main valve seat and the fluid. A flow control valve which is supplied to an outflow pipe.   The said drive part has a stepping motor and the screw feed mechanism which converts rotation of the rotor of this stepping motor into the contact / separation operation | movement with respect to the said subvalve seat of the said subvalve body, It is characterized by the above-mentioned. 1. The flow control valve according to 1.   The main valve body has a guided portion that protrudes toward the sub-valve main body, and the sub-valve main body has a guide portion that guides the guided portion so as to be slidable in the opening and closing direction of the main valve body. The flow control valve according to claim 1 or 2, wherein Said main valve body to form a large diameter portion to form a flow path to the auxiliary valve chamber the gap formed between the inner wall of the main valve chamber and該径most from said main valve chamber and which, flow control valve according to any one of claims 1 to 3, characterized in that the cross-sectional area of the flow channel is constant over the moving direction entire length of the main valve body.

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