JP2012132498A - Electric pilot type control valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric pilot type control valve which allows arbitrary and fine adjustment of valve opening, effectively suppresses generation of noise, and achieves excellent responsiveness, operation stability, control characteristic or the like.SOLUTION: A valve body 20 is provided with a communication hole 70 for communicating between a pilot passage 28 and a valve chamber 13. A pilot valve body 35 is provided with a main pilot valve body part 36A for opening and closing an upper end on the back pressure chamber side 28a in the pilot passage 28, and an auxiliary pilot valve 36B for opening and closing a pilot outlet 28b. When the pilot valve body 35 is moved upward, the main pilot valve body part 36A opens the upper end on the back pressure chamber side 28a in the pilot passage 28 shortly after the auxiliary pilot valve 36B opens the pilot outlet 28b.

Description

  The present invention relates to a pilot-type control valve suitable for use in a heat pump apparatus such as an air conditioner, and more particularly to an electric pilot-type control valve using an electric type as a pilot valve.

  Generally, the pilot type control valve is classified into an electromagnetic type using an electromagnetic valve as a pilot valve and an electric type using an electric valve as a pilot valve, both of which open a small-diameter pilot valve portion, In response to this, the large-diameter main valve can be opened, which has the advantage that the main valve can be opened and closed with a small driving force. Only two positions in the fully open state can be taken, and the valve opening degree (opening area) cannot be finely adjusted. On the other hand, the electric type has the advantage that the valve opening degree (opening area) can be finely adjusted by changing the number of pulses supplied to the electric motor (stepping motor).

  FIG. 5 is a longitudinal sectional view showing an example of such an electric pilot type control valve (see also Patent Document 1 below).

  The electric pilot type control valve 1 'in the illustrated example is suitable for being distributed between an outdoor unit and an indoor unit in an air conditioner such as a multi air conditioner. And an electric pilot valve 7 provided in the motor.

  The main valve 5 has a valve body 10 including a cylindrical valve chamber cylinder 11 having a bottom with a hole, and a valve seat member 12 hermetically fixed to the bottom hole of the valve chamber cylinder 11 by welding or the like. The valve body 10 is formed with a valve chamber 13, and an inlet conduit (joint) 41 for introducing a high-pressure refrigerant into the valve chamber 13 is connected to the peripheral side portion, and the bottom portion (the valve seat member 12). ) Is connected to an outlet conduit (joint) 42 for leading out the refrigerant from the valve chamber 13, and the defined base member 32 is welded so as to close the upper surface opening of the valve body 10 (valve chamber cylinder 11). It is sealed and fixed by etc.

  The valve seat member 12 of the main valve 5 is provided with a main valve outlet 14 with a main valve seat 14a having a conical surface, and the valve seat member 12 in the valve body 10 (valve chamber cylinder 11) has an inverted convex cross section. A piston-shaped main valve body 20 is slidably fitted, and a back pressure chamber 33 is defined between the main valve body 20 (the large diameter portion 20A thereof) and the defining base member 32. Has been.

  The main valve body 20 is provided with a main valve body portion 21 that contacts and separates from the main valve seat 14a at a lower end portion (small diameter portion 20B), and the large diameter portion 20A of the main valve body 20 includes the A small diameter equalizing hole 24 is formed so as to allow the valve chamber 13 and the back pressure chamber 33 to communicate with each other, and a sealing material 58 is disposed between the large diameter portion 20 </ b> A and the valve chamber cylinder 11. .

  The main valve body 20 is always urged in the valve opening direction (upward) by a compression coil spring (valve opening spring) 25 that is compressed between the lower end surface portion 20a of the large diameter portion 20A and the valve seat member 12. Has been. Specifically, an undesired behavior of the upper end portion 25a is suppressed on the lower end surface portion 20a (upper spring receiving portion) of the large diameter portion 20A of the main valve body 20 that receives the upper end portion 25a of the compression coil spring 25. Accordingly, a short cylindrical downward projecting portion 20b into which the upper end portion 25a is extrapolated is provided.

  The valve seat member 12 includes a small diameter cylindrical portion 12A in which a main valve outlet 14 with a main valve seat 14a is formed, a large diameter cylindrical portion 12B in which the outlet conduit (joint) 42 is inserted and connected, A stepped hook-like portion 12C to which the lower end of the valve chamber cylinder 11 is connected, and a stepped surface (upper surface) 12c of the stepped hook-like portion 12C receives the lower end 25b of the compression coil spring 25; In order to suppress an undesired behavior of the lower end portion 25b of the compression coil spring 25, the lower end portion 25b is extrapolated to the small diameter cylindrical portion 12A.

  Further, a pilot passage 28 is formed in the main valve body 20 so as to penetrate the center vertically. Specifically, a pilot valve seat member 22 to which a pilot valve body portion 36 provided at a lower end portion of a pilot valve body 35 to be described later contacts and separates is press-fitted and fixed at the center of the upper surface portion of the main valve body 20. The pilot valve seat member 22 is provided with a pilot valve port 27 with a pilot valve seat 27 a, and this pilot valve port 27 is an upper end portion of the pilot passage 28.

  The electric pilot valve 7 provided on the upper side of the main valve 5 includes a stepped needle-like pilot valve body 35 having a pilot valve body portion 36 that contacts and separates from the pilot valve seat 27a, and the defined pedestal. A can 34 whose lower end is sealed and joined to the member 32 by welding, a rotor 55 disposed around the inner periphery of the can 34 with a predetermined gap, and rotated about the rotation axis O, the rotor 55 And a stator 50 </ b> A that is externally mounted on the can 34 so as to be rotationally driven.

  The stator 50A includes a yoke 51 made of a magnetic material, upper and lower stator coils 53, 53 wound around the yoke 51 via a bobbin 52, and a resin mold cover 56, and is stepped by the rotor 55 and the stator 50A. A motor 50 is configured.

  The can 34 is made of a non-magnetic metal plate such as stainless steel as a material and is formed into a cylindrical shape having a ceiling by deep drawing or the like, and the lower end portion (opening edge portion) of the can 34 is the defining pedestal member 32. It is hermetically sealed by butt welding to the upper stepped portion, and the inside is kept airtight.

  The drive mechanism for bringing the pilot valve body 35 (the pilot valve body portion 36) into and out of contact with the pilot valve seat 27a is arranged on a cylindrical guide bush 37 into which the pilot valve body 35 is slidably inserted and an outer periphery thereof. The screw feed mechanism 60 is formed on the existing cylindrical valve body holder 40 having a lower opening. That is, the lower end portion of the guide bush 37 is press-fitted (or screwed) and fixed to the defining pedestal member 32, and a male screw portion 62 is formed in the vicinity of the center portion thereof. A female screw portion (moving screw portion) 61 that is screwed into the male screw portion (fixed screw portion) 62 is formed, and the upper small-diameter portion of the pilot valve body 35 is capable of relative rotation and relative movement at the center of the nadir. It is inserted. The upper end portion of the upper small-diameter portion of the pilot valve body 35 is press-fitted and fixed to a nut 44 placed on the top surface (concave portion) of the valve body holder 40.

  The pilot valve body 35 is always urged downward by a buffering coil spring 38 that is mounted between the nadir of the valve body holder 40 and the intermediate step portion of the pilot valve body 35. A pressure equalizing hole 37 a for equalizing the pressure in the back pressure chamber 33 and the can 34 is formed on the side surface of the guide bush 37.

  A return spring 45 made of a coil spring is provided on the top of the valve body holder 40. The return spring 45 abuts against the ceiling of the can 34 when the fixed screw portion 62 of the guide bush 37 and the moving screw portion 61 of the valve element holder 40 are unscrewed, and the return spring 45 contacts the ceiling of the can 34. It works to restore the screwing.

  The valve body holder 40 and the rotor 55 are coupled via a support ring 43, and the upper protrusion of the valve body holder 40 is caulked and fixed to the support ring 43, whereby the rotor 55, the support ring 43, and the valve body holder are fixed. 40 are integrally connected.

  A lower stopper body (fixed stopper) 66 constituting one of the stopper mechanisms is fixed to the guide bush 37, and an upper stopper body (moving stopper) 67 constituting the other stopper mechanism is fixed to the valve body holder 40. ing.

  The outer diameter Da of the large-diameter portion 20A of the main valve body 20 is 1.5 to 3 times the diameter Db of the main valve outlet 14, and is larger than the outer diameter Dc of the rotor 55. The diameter of the main valve outlet 14 is 3 to 9 times the diameter of the pilot valve port 27, and the diameter of the pilot valve port 27 is larger than the diameter (minimum portion) of the pressure equalizing hole 24.

Here, in the electric pilot type control valve 1 ′ shown in the drawing, the pressure in the valve chamber 13 is P1, the pressure in the back pressure chamber 33 is P2, the pressure in the main valve outlet 14 is P3, and the valve chamber cylinder 11 is horizontally disconnected. Ap is the area (pressure receiving area of the main valve body 20), Av is the horizontal cross-sectional area of the main valve outlet 14, and Pf is the urging force of the compression coil spring (open valve spring) 25. If the force, the force that pushes down the main valve body 20 is the valve closing force, the main valve opening condition is
Valve closing force = P2 × Ap <Valve opening force = P1 × (Ap−Av) + P3 × Av + Pf
It becomes.

  In the electric pilot-type control valve 1 'of the illustrated example having such a configuration, the main valve 5 is in a closed state (the main valve body portion 21 of the main valve body 20 is seated on the main valve seat 14a. And the electric pilot valve 7 is in an open state (a state in which the pilot valve body 35 is separated from the pilot valve seat 27a), the stepping motor 50 (stator coils 53, 53) is, for example, in a rank phase. When pulse supply is performed and the rotor 55 is rotated in one direction with respect to the guide bush 37, the valve body holder 40 is fed by screw feed between the fixing screw portion 62 of the guide bush 37 and the moving screw portion 61 of the valve body holder 40. Moves downward, the pilot valve body portion 36 of the pilot valve body 35 is seated and pressed against the pilot valve seat 27a, and is closed.

  At this time, the upper stopper body 67 is not yet in contact with the lower stopper body 66, and the valve body holder 40 is further rotated and lowered while the pilot valve body portion 36 of the pilot valve body 35 is seated on the pilot valve seat 27a. At this time, since the valve body holder 40 is lowered with respect to the pilot valve body 35, the descent force of the valve body holder 40 is absorbed by the compression coil spring 38 being compressed. Thereafter, when the rotor 55 further rotates and the valve body holder 40 is lowered, the upper stopper body 67 comes into contact with the lower stopper body 66 and the valve body holder 40 is lowered even if the pulse supply to the stator coils 53 and 53 is continued. It is forcibly stopped.

  When the main valve 5 and the pilot valve 7 are in the closed state as described above, the high-pressure (pressure P1) refrigerant introduced from the inlet conduit 41 into the valve chamber 13 enters the back pressure chamber 33 via the pressure equalizing hole 24. Since the pressure P2 in the back pressure chamber 33 is increased, the main valve body portion 21 of the main valve body 20 is strongly pressed against the main valve seat 4a. FIG. 6 shows the flow rate of the refrigerant flowing out from the inlet conduit 41 side to the outlet conduit 42 side through the main valve outlet 14 in the electric pilot-type control valve 1 ′ at this time (number of pulses from 0 to Ta). 0 as it is.

  Since the main valve 5 and the pilot valve 7 are in the closed state, for example, pulses are supplied to the stepping motor 50 (stator coils 53, 53) in the opposite phase, and the rotor 55 is reversed with respect to the guide bush 37. When the number of pulses (rotation amount) becomes Ta due to screw feed between the fixing screw portion 62 of the guide bush 37 and the moving screw portion 61 of the valve body holder 40, the valve body holder 40 moves upward. Accordingly, the pilot valve body portion 36 of the pilot valve body 35 begins to move away from the pilot valve seat 27a, the pilot valve 7 begins to open, and the refrigerant in the back pressure chamber 33 passes through the pilot passage 28 until the number of pulses reaches Tb. (The refrigerant flow rate of the control valve 1 ′ gradually increases slightly), and the pressure P2 in the back pressure chamber 33 is gradually reduced.

  When the number of pulses (rotation amount) reaches Tb, the pilot valve body portion 36 of the pilot valve body 35 is separated from the pilot valve seat 27a by a predetermined distance, the refrigerant flow rate becomes Ja, and the force (valve opening) pushes up the main valve body 20. Force) overcomes the force (valve closing force) that pushes down the main valve body 20, the main valve body 20 is pushed up, the main valve body portion 21 begins to move away from the main valve seat 4a, and the main valve 5 begins to open.

  Subsequently, when the number of pulses is further increased, the main valve body 20 is pushed up so as to follow the upward movement of the pilot valve body 35 until the number of pulses reaches Tc. Specifically, in a state where the pilot valve body portion 36 of the pilot valve body 35 is separated from the pilot valve seat 27a by the predetermined distance, that is, in a state where the opening degree of the electric pilot valve 7 is maintained substantially constant, The body 35 and the main valve body 20 move upward (in the valve opening direction) together. As a result, when the number of pulses (rotation amount) is between Tb and Tc, the refrigerant flow rate in the electric pilot control valve 1 increases smoothly with a constant gradient. That is, until the number of pulses is changed from Tb to Tc, the pilot valve body 35 and the main valve body 20 remain in a state where the pilot valve body portion 36 of the pilot valve body 35 is separated from the pilot valve seat 27a by a predetermined distance. Increases by the same distance with respect to the number of pulses (rotation amount) (so that dimensional specifications and the like of each part are set).

  When the number of pulses reaches Tc, the upper surface stopper portion 29 of the main valve body 20 comes into contact with the fixed stopper 39 provided on the lower surface of the defining pedestal member 32 and the main valve body 20 is prevented from rising. Therefore, even if the pulse number exceeds Tc, the refrigerant flow rate (opening degree) in the electric pilot-type control valve 1 does not become larger than Jb when the pulse number is Tc, and the opening degree at this time (maximum opening). Degree) will be maintained.

  As described above, in the electric pilot type control valve 1 ′ shown in the figure, the pilot valve is an electric type instead of an electromagnetic type, so that the refrigerant flow rate is adjusted according to the number of pulses supplied to the pilot valve 7. The pressure can be changed smoothly and the pressure equalization time can be shortened. Therefore, the valve opening degree (opening area) can be arbitrarily and finely adjusted.

JP 2008-64301 A

  However, in the conventional electric pilot control valve 1 ′ as described above, the pressure balance between the valve chamber 13 and the back pressure chamber 33 becomes unstable when the main valve 5 is opened, and so-called chattering occurs. There was a problem that an unusual sound (continuous beating sound, vibration sound) was generated. The occurrence of chattering is considered to be caused by the following.

  That is, as described above, when the pilot valve 7 starts to open, the refrigerant in the back pressure chamber 33 starts to escape to the main valve outlet 14 side through the pilot passage 28, and the pressure P2 in the back pressure chamber 33 gradually decreases, and the back pressure chamber 33 gradually decreases. When the pressure P2 in the pressure chamber 33 decreases until the main valve opening condition [valve closing force = P2 × Ap <valve opening force = P1 × (Ap−Av) + P3 × Av + Pf]], the main valve 5 starts to open. . When the main valve 5 is opened, the pressure P1 in the valve chamber 13 is considerably larger than the pressure P3 in the main valve outlet 14, so that the refrigerant in the valve chamber 13 passes through the gap between the main valve seat 14a and the main valve body 21. As a result, the pressure P1 in the valve chamber 13 drops rapidly.

  Thus, when the pressure P1 in the valve chamber 13 suddenly decreases, [valve closing force> valve opening force] is established, the main valve body 20 is rapidly pushed down, and the main valve body portion 21 is hit against the main valve seat 14a. Is closed (sounding sound). When the main valve 5 is closed in this way, the flow rate of refrigerant flowing out to the main valve outlet 14 side is only through the pilot passage 28, so the pressure P2 in the back pressure chamber 33 decreases, and [valve closing force < Valve opening force], the main valve 5 opens again, and the same behavior as described above is repeated, and this becomes chattering.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an electric pilot type control valve capable of effectively suppressing chattering when the main valve is opened. .

  In order to achieve the above object, the electric pilot type control valve according to the present invention is basically slidably fitted in a valve body provided with a valve chamber and a main valve outlet, and the valve body. A piston-type main valve body that opens and closes the main valve outlet, a main valve that has a defining member that defines a back pressure chamber between the main valve body, and an electric motor that has a needle-like pilot valve body A pilot valve, and a pressure equalizing hole that communicates the valve chamber and the back pressure chamber, the back pressure chamber communicates with the main valve outlet, and the pilot valve body is inserted into the main valve body. A pilot passage and a communication hole for communicating the pilot passage and the valve chamber are provided, and a main pilot valve body portion for opening and closing the back pressure chamber side in the pilot passage is provided in the pilot valve body. , Below the communication hole in the pilot passage When the pilot valve body part is provided to open and close the pilot outlet provided on the side, and the pilot valve body is moved upward, the sub pilot valve body part slightly delays after opening the pilot outlet. The main pilot valve element is configured to open the back pressure chamber side in the pilot passage.

  In a preferred aspect, the fluid in the back pressure chamber is passed through the pilot passage between the portion of the pilot valve body between the main pilot valve body portion and the sub pilot valve body portion and the inner peripheral surface of the pilot passage. A passage having an effective passage sectional area for allowing escape to the main valve outlet is larger than the sum of the effective passage sectional area of the pressure equalizing hole and the effective passage sectional area of the communication hole.

  In this case, in a preferred aspect, the main pilot valve body portion is configured by a large-diameter portion that is slidably fitted into an upper end portion of the pilot passage, and is below the main pilot valve body portion in the pilot valve body. Is constituted by a small diameter portion having a smaller diameter than the main pilot valve body portion.

  In another preferred aspect, the dimensional shape of each part is set so that the main valve body moves upward so as to follow the upward movement of the pilot valve body.

 In another preferred embodiment, a valve opening spring that urges the main valve body in the valve opening direction is further provided.

  In still another preferred aspect, the electric pilot valve includes a can, a rotor disposed on an inner periphery of the can, a stator sheathed on the can to rotationally drive the rotor, the rotor, and the rotor. A drive mechanism that is disposed between the pilot valve body and moves the pilot valve body in an axial direction by utilizing rotation of the rotor.

  In the electric pilot type control valve according to the present invention, the main valve body is provided with a communication hole for communicating the pilot passage and the valve chamber, and the main pilot for opening and closing the back pressure chamber side in the pilot passage is provided in the pilot valve body. A valve body is provided, and a sub pilot valve body for opening and closing the pilot outlet is provided. When the pilot valve body is moved upward, the sub pilot valve body opens a little after the pilot outlet is opened. Since the main pilot valve body opens the back pressure chamber side of the pilot passage after a delay, the main pilot valve body portion opens from the back pressure chamber side of the pilot passage after the sub pilot valve body opens the pilot outlet. Until the upper end is opened, the pressure P1 in the valve chamber is lowered, and thereby the difference between the pressure P1 in the valve chamber and the pressure P3 at the main valve outlet before the main valve is opened So that is small.

  Thus, when the main valve is opened, the pressure difference between the valve chamber pressure P1 and the main valve outlet pressure P3 is reduced, so that the refrigerant in the valve chamber flows to the main valve outlet immediately after the main valve starts to open. As a result, the pressure P1 in the valve chamber is prevented from dropping rapidly, and the pressure balance between the valve chamber and the back pressure chamber is less likely to be lost when the main valve is opened, resulting in chattering. Can be effectively suppressed, and an unpleasant noise (continuous beating sound, vibration sound) can be suppressed.

BRIEF DESCRIPTION OF THE DRAWINGS It is a principal part longitudinal cross-sectional view which shows one Example of the electrically driven pilot type control valve which concerns on this invention, and shows the main pilot valve body part and subpilot valve body part of a pilot valve: a closed state, and the main valve: a closed state Yes. It is a principal part longitudinal cross-sectional view used for operation | movement description of the electrically driven pilot type control valve shown by FIG. 1, The main pilot valve body part of a pilot valve: A closed state, a sub pilot valve body part: An open state, A main valve: Indicates the closed state. It is a principal part longitudinal cross-sectional view used for operation | movement description of the electrically driven pilot type control valve shown by FIG. 1, The main pilot valve body part of a pilot valve: An open state, a subpilot valve body part: An open state, Main valve: Indicates the closed state. The graph with which it uses for operation | movement description of the electrically driven pilot type control valve shown by FIG. It is a longitudinal cross-sectional view which shows an example of the conventional electric pilot type control valve, and has shown the pilot valve: closed state and the main valve: closed state. FIG. 6 is a graph for explaining the operation of the electric pilot type control valve shown in FIG. 5.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is an enlarged longitudinal sectional view of a main part showing an embodiment of an electric pilot type control valve according to the present invention.

  The electric pilot type control valve 1 of this embodiment is substantially the same as the conventional electric pilot type control valve 1 ′ shown in FIG. 5 and the electric pilot valve 7 (the portion above the defining pedestal member 32). Since the same structure and the difference are the main valve body 20 and the pilot valve body 35 below the defining pedestal member 32, parts corresponding to those in FIG. A duplicate description will be omitted, and the following will focus on the differences.

  In the electric pilot type control valve 1 of the present embodiment, the main valve body 20 is connected to the pressure equalizing hole (vertical hole) 24 and the back pressure chamber 33 and the main valve outlet 14 communicating with the valve chamber 13 and the back pressure chamber 33. In addition to the pilot passage 28 communicating with the pilot passage 28, a communication hole (lateral hole) 70 for communicating the lower portion of the pilot passage 28 and the valve chamber 13 is provided, and a pilot valve body 35 (lower portion) is inserted into the pilot passage 28. ing.

  The pilot valve body 35 is provided with a sub pilot valve body portion 36B for opening and closing a pilot outlet 28b with a valve seat 28c provided on the downstream side of the communication hole 70 in the pilot passage 28, and at the back of the pilot passage 28. When the main pilot valve body portion 36A for opening and closing the pressure chamber side upper end portion 28a is provided and the pilot valve body 35 is moved upward, the sub pilot valve body portion 36B is slightly delayed after opening the pilot outlet 28b. Thus, the main pilot valve body portion 36A opens the back pressure chamber side upper end portion 28a of the pilot passage 28.

  The main pilot valve body portion 36A is composed of a large-diameter portion that is slidably fitted into the back pressure chamber side upper end portion 28a of the pilot passage 28, and the lower side of the pilot valve body 35 from the main pilot valve body portion 36A is The main pilot valve body portion 36A has a smaller diameter portion 36C. The pilot valve body 35 has a small diameter portion 36C between the auxiliary pilot valve body portion 36B and the main pilot valve body portion 36A and the pilot passage 28. The effective passage cross-sectional area for allowing the refrigerant in the back pressure chamber 33 to escape to the main valve outlet 14 through the pilot passage 28 between the inner peripheral surface and the effective passage cross-sectional area of the pressure equalizing hole 24 is effective. An escape passage 72 larger than the sum of the passage cross-sectional areas is formed.

  In the state where the main pilot valve body portion 36A is fitted and inserted into the back pressure chamber side upper end portion 28a of the pilot passage 28 and is closed, the back pressure chamber side upper end portion of the main pilot valve body portion 36A and the pilot passage 28 is closed. The refrigerant in the back pressure chamber 33 escapes through the sliding surface gap formed between the inner peripheral surface 28a and slightly leaks to the flow path 72 side, but has little influence on the valve operation.

  Next, the operation of the electric pilot type control valve 1 of the present embodiment having the above-described configuration will be described with reference to FIG. 1, FIG. 2, FIG. 3, and FIG.

  As shown in FIG. 1, when the main valve 5 and the pilot valve 7 are in the closed state, when the pulse is supplied to the stepping motor 50 and the rotor 55 is rotated with respect to the guide bush 37, FIG. As shown in FIG. 4, when the number of pulses (rotation amount) reaches Tg, the sub pilot valve body portion 36B moves to the valve seat 28c of the pilot outlet 28b as the valve body holder 40 and the pilot valve body 35 move upward. The pilot outlet 28b begins to open. When the pilot outlet 28b is opened, the refrigerant in the valve chamber 13 flows out to the main valve outlet 14 through the communication hole 70 → the lower part of the pilot passage 28 → the pilot outlet 28b, and the pressure P1 in the valve chamber 13 gradually decreases. Along with this, the pressure P2 in the back pressure chamber 33 also drops to the valve chamber 13 through the pressure equalizing hole 24 and gradually decreases (a state of approximately P1 = P2), and the pressure P1 in the valve chamber 13 and the pressure P3 at the main valve outlet 14 The pressure difference between and gradually decreases. However, at this time, the main valve opening condition [valve closing force = P2 × Ap <valve opening force = P1 × (Ap−Av) + P3 × Av + Pf] is not satisfied, and thus the main valve 5 is not yet opened. The refrigerant flow rate at this time is a relatively small amount of Ka.

  Subsequently, when the number of pulses (the amount of rotation) increases from Tg to Th, in other words, as shown in FIG. 3, the pilot valve body 35 is slightly delayed after the auxiliary pilot valve body portion 36B opens the pilot outlet 28b. The main pilot valve body portion 36 </ b> A opens the back pressure chamber side upper end portion 28 a in the pilot passage 28. As a result, the refrigerant in the back pressure chamber 33 escapes and flows out to the main valve outlet 14 via the flow path 72 → the pilot outlet 28b.

  In this case, the refrigerant in the valve chamber 13 also flows to the back pressure chamber 33 via the pressure equalizing hole 24 and also flows to the main valve outlet 14 via the communication hole 70, but the effective passage cross-sectional area of the escape flow path 72 is equalized. Since the effective passage cross-sectional area of the hole 24 and the effective passage cross-sectional area of the communication hole 70 are set larger than each other, the flow rate of the refrigerant flowing through the escape passage 72 is back pressure from the valve chamber 13 through the pressure equalizing hole 24. The sum of the refrigerant flow rate flowing to the chamber 33 and the refrigerant flow rate flowing from the valve chamber 13 through the communication hole 70 to the main valve outlet 14 is greater than the sum of the pressure reduction degree of the valve chamber 13 and the back pressure chamber 33. The pressure P2 is reduced.

  When the pressure P2 in the back pressure chamber 33 decreases until the main valve opening condition [valve closing force = P2 × Ap <valve opening force = P1 × (Ap−Av) + P3 × Av + Pf] (the number of pulses is When the pressure reaches Ti, the refrigerant flow rate at this time is Kb), and the main valve 5 starts to open. When the main valve 5 is opened, the refrigerant in the valve chamber 13 flows between the main valve seat 14a and the main valve body 21 to the main valve outlet 14 side.

  Here, in the electric pilot type control valve 1 of the present embodiment, the main valve body 20 is provided with a communication hole 70 for communicating the pilot passage 28 and the valve chamber 13, and the pilot valve body 35 is provided in the pilot passage 28. A main pilot valve body portion 36A for opening and closing the back pressure chamber side upper end portion 28a is provided, and a sub pilot valve body portion 36B for opening and closing the pilot outlet 28b is provided, and the pilot valve body 35 moves upward. Since the main pilot valve body portion 36A opens the back pressure chamber side upper end portion 28a of the pilot passage 28 after a slight delay after the sub pilot valve body portion 36B opens the pilot outlet 28b, The main pilot valve body 36A is located on the back pressure chamber side upper end of the pilot passage 28 from when the pilot valve body 36B opens the pilot outlet 28b. Until the valve 28a is opened, the pressure P1 in the valve chamber 13 is reduced, and thereby the pressure difference between the pressure P1 in the valve chamber 13 and the pressure P3 at the main valve outlet 14 is reduced until the main valve 5 is opened. Will be.

  Thus, when the main valve 5 is opened, the pressure difference between the pressure P1 of the valve chamber 13 and the pressure P3 of the main valve outlet 14 is reduced, so that the refrigerant in the valve chamber 13 immediately after the main valve 5 starts to open. Does not flow out rapidly to the main valve outlet 14, so that the pressure P1 in the valve chamber 13 is prevented from dropping rapidly, and the pressure balance between the valve chamber 13 and the back pressure chamber 33 is maintained when the main valve 5 is opened. As a result, the occurrence of chattering can be effectively suppressed, and an unpleasant noise (continuous beating sound, vibration sound) can be suppressed.

  In the above embodiment, when the number of pulses is further increased from Ti, the main valve body 20 is adapted to follow the upward movement of the pilot valve body 35 as in the conventional example until the number of pulses reaches Tj. Is pushed up. Thereby, when the number of pulses (rotation amount) is between Ti and Tj, the refrigerant flow rate in the electric pilot type control valve 1 increases smoothly with a constant gradient. When the number of pulses reaches Tj, the upper surface stopper portion 29 of the main valve body 20 comes into contact with the fixed stopper 39 provided on the lower surface of the defining pedestal member 32 to prevent the main valve body 20 from rising, and the refrigerant flow rate Does not become larger than Kc when the number of pulses is Tj, and the flow rate at this time is maintained.

Of course, the compression coil spring 25 need not be provided.
Furthermore, the main valve body 20 may be urged toward the main valve seat 14a by using a spring of reference numeral 25 as a tension coil spring.

  Whether or not the compression coil spring 25 is used or not, or whether or not the main valve body 20 is urged toward the main valve seat 14a by using a tension coil spring instead of the compression coil spring is obtained from the main valve body 20. What is necessary is just to determine suitably according to the opening-and-closing characteristic to be performed.

DESCRIPTION OF SYMBOLS 1 Electric pilot type control valve 5 Main valve 7 Electric pilot valve 10 Valve main body 13 Valve chamber 14 Main valve outlet 14a Main valve seat 20 Main valve body 24 Pressure equalizing hole 25 Compression coil spring 28 Pilot passage 28a Back pressure chamber side upper end Portion 28b Pilot outlet 32 Definition base member 33 Back pressure chamber 35 Pilot valve body 36A Main pilot valve body portion 36B Sub pilot valve body portion 40 Valve body holder 50 Stepping motor 55 Rotor 70 Communication hole

Claims (6)

A valve body provided with a valve chamber and a main valve outlet, a piston-type main valve body that is slidably inserted into the valve body and opens and closes the main valve outlet, and a back between the main valve body An electric pilot type control valve comprising a main valve having an defining member that defines a pressure chamber, and an electric pilot valve having a needle-like pilot valve body,
A pressure equalization hole that communicates the valve chamber and the back pressure chamber to the main valve body, a pilot passage that communicates the back pressure chamber and the main valve outlet, and the pilot valve body is inserted, and the pilot A communication hole for communicating the passage and the valve chamber is provided,
The pilot valve body is provided with a main pilot valve body portion for opening and closing the back pressure chamber side in the pilot passage, and for opening and closing a pilot outlet provided on the downstream side of the communication hole in the pilot passage. Of the secondary pilot valve body,
When the pilot valve body is moved upward, the main pilot valve body portion opens the back pressure chamber side in the pilot passage with a slight delay after the sub pilot valve body portion opens the pilot outlet. An electrically operated pilot type control valve.   Between the portion of the pilot valve body between the main pilot valve body portion and the sub pilot valve body portion and the inner peripheral surface of the pilot passage, fluid in the back pressure chamber is passed through the pilot passage to the main valve outlet. 2. The flow path having an effective passage cross-sectional area for escaping larger than a sum of an effective passage cross-sectional area of the pressure equalizing hole and an effective passage cross-sectional area of the communication hole is formed according to claim 1. Electric pilot type control valve.   The main pilot valve body portion is configured by a large-diameter portion that is slidably inserted into an upper end portion of the pilot passage, and the lower side of the main pilot valve body portion in the pilot valve body is the main pilot valve body The electric pilot-type control valve according to claim 1, wherein the electric pilot-type control valve is configured by a small-diameter portion having a smaller diameter than the portion.   4. The electric motor according to claim 1, wherein the dimensional shape of each part is set so that the main valve body moves upward so as to follow the upward movement of the pilot valve body. 5. Type pilot type control valve.   5. The electric pilot-type control valve according to claim 1, further comprising a valve-opening spring that biases the main valve body in a valve-opening direction.   The electric pilot valve includes a can, a rotor disposed on the inner periphery of the can, a stator externally mounted on the can to rotationally drive the rotor, and between the rotor and the pilot valve body. An electrically driven pilot type according to any one of claims 1 to 5, further comprising: a drive mechanism that is arranged and moves the pilot valve body in an axial direction by utilizing rotation of the rotor. Control valve.

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