JP2006316852A - Pilot operated solenoid valve and heat exchange system using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pilot operated solenoid valve which is considered so that the valve opening operation of a valve element is performed to be relatively slow during opening a valve, avoiding problems with the durability and reliability of a conventional pilot operated solenoid valve. <P>SOLUTION: The pilot operated solenoid valve comprises the valve element 36 stored in a valve body 21 for partitioning a first valve chest 22a from a second valve chest 22b and for abutting a valve seat 26 facing the first valve chest 22a, a piston 23 for partitioning the second valve chest 22b from a tank chamber 22c, a compression spring 42 for energizing the piston 23 to be spaced wider from the valve element 36, a first restricting passage 37 formed in the valve element 36 for communicating the first valve chest 22a with the second valve chest 22b, a second restricting passage 41 formed in the piston 23 for communicating the second valve chest 22b with the tank chamber 22c, a stepped part 24 for restricting a gap to be formed between the valve element 36 and the piston 23 in the state that the valve element 36 abuts on the valve seat 26, a bellows 38 for energizing the piston 23 toward the stepped part 24, and a pilot valve 31 for opening/closing a pilot flow path 30 communicated with an outlet port 27 and the second valve chest 22b. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a pilot-operated solenoid valve capable of performing a valve opening operation of a valve body relatively slowly and a heat exchange system incorporating the same.

  As a heat exchange system having a refrigeration cycle, for example, in a refrigerator, a compressor that compresses refrigerant in a gas phase, a condenser that cools and liquefies the compressed refrigerant, and an expansion valve that reduces the pressure of the liquefied refrigerant And an evaporator that vaporizes the liquid low-temperature refrigerant and returns it to the compressor is incorporated in the refrigerant circulation path. In such a refrigeration cycle, when the compressor is stopped, the refrigerant flows from the high-temperature and high-pressure condenser side through the expansion valve to the low-temperature and low-pressure evaporator side to condense and liquefy, which is restarted. Since it is drawn into the compressor, there is a problem that the compressor is damaged. For this reason, an electromagnetic valve that can close the refrigerant circulation system is provided between the condenser and the expansion valve so that the refrigerant does not flow from the condenser side to the evaporator side through the expansion valve while the compressor is stopped. Incorporated in the circulation path of the common is common. In this case, when the region to be cooled is lower than the target set temperature, the solenoid valve is driven to block the circulation path, the compressor is operated in this state, and the refrigerant in the evaporator is recovered in the condenser. The operation of the compressor is stopped when the pressure of the refrigerant in the evaporator decreases to a predetermined pressure. In addition, when the cooling target area rises above the target set temperature, the solenoid valve is switched to the open state and the refrigerant is supplied to the evaporator, and the pressure of the refrigerant in the evaporator increases accordingly. The compressor is activated and the refrigerant circulates in the circulation system.

  In a heat exchange system that incorporates an electromagnetic valve that opens and closes the refrigerant circulation path according to the temperature of the area to be cooled, high-pressure refrigerant is supplied to the expansion valve when the solenoid valve switches from the closed state to the open state. Is done. As a result, shock pressure may act on the expansion valve, and the expansion valve may be damaged by a so-called water hammer phenomenon. Therefore, electromagnetic valves as shown in Patent Document 1 and Patent Document 2 have been proposed.

Japanese Patent Laid-Open No. 10-318425 JP-A-11-344145

  Since the pilot type solenoid valve disclosed in Patent Document 1 has a lip seal structure, leakage at the lip seal portion increases with time, and there is a problem in durability. In addition, since this pilot type solenoid valve has an integrated piston and valve body, it takes time until the valve body actually starts to open after the pilot valve is driven. was there.

  Similar to the pilot solenoid valve disclosed in Patent Document 2, the pilot solenoid valve disclosed in Patent Document 2 also has a structure for avoiding damage to the expansion valve due to a liquid hammer phenomenon that occurs when the solenoid valve is suddenly opened and closed in the refrigeration cycle. However, the time required for displacing the valve element from the fully closed state to the fully open state is relatively short, and the impact mitigation ability for the expansion valve was not so excellent.

  An object of the present invention is to provide a pilot-actuated electromagnetic valve and a heat exchange system using the same, in consideration that valve opening operation of the valve body is performed relatively slowly when the valve is opened.

  According to a first aspect of the present invention, an inlet port and an outlet port are formed, and a valve body having a cavity communicating with the inlet port and the outlet port formed therein is accommodated in the cavity so as to be reciprocally movable. A valve body that partitions the cavity into a first valve chamber and a second valve chamber side in which the inlet port and the outlet port communicate with each other, and can come into contact with a valve seat formed in the outlet port so as to face the first valve chamber And the second valve chamber formed in the valve body so as to reciprocate along a direction opposite to the valve body, and a first throttle passage communicating the first valve chamber and the second valve chamber. And a piston that partitions the second valve chamber side into a second valve chamber and a tank chamber, and is interposed between the piston and the valve body and urges the piston so that the distance between them is increased. 1 spring member and formed on the piston A second throttle passage communicating the second valve chamber and the tank chamber, and formed in the cavity, formed between the valve body and the piston in a state where the valve body is in contact with the valve seat. A stopper that defines a gap to be formed, a second spring member that biases the piston toward the stopper, and a pilot flow path that is formed in the valve body and communicates the outlet port and the second valve chamber And a pilot valve for opening and closing the pilot flow path.

  In the pilot operated solenoid valve of the present invention, when the pilot valve closes the pilot flow path, the valve body abuts on the valve seat by the spring force of the first spring member, and the inlet port and the outlet port are not in communication. It becomes. In this state, the piston comes into contact with the stopper by the spring force of the second spring member, and a gap is formed between the valve body and the piston.

  When the pilot valve is driven from this state to open the pilot flow path, the fluid in the second valve chamber flows out from the pilot flow path to the outlet port, so that the pressure of the fluid in the first valve chamber is the spring of the first spring member. The valve body is displaced until it overcomes the force and comes into contact with the piston. As a result, fluid begins to flow from the inlet port to the outlet port through a slight gap formed between the valve seat and the valve body. Further, due to the differential pressure between the fluid in the first valve chamber and the fluid in the second valve chamber, the fluid in the tank chamber is pushed out from the second throttle passage into the second valve chamber, and from there, passes through the pilot flow path to the outlet port. Therefore, the piston also moves relatively slowly with the valve body in the direction away from the valve seat. As a result, the amount of fluid flowing out from the outlet port gradually increases as the valve body moves away from the valve seat.

  When the pilot valve is driven again from this state to close the pilot flow path, the fluid begins to fill the second valve chamber from the first valve chamber through the first throttle passage, and the spring force of the first spring member causes First, the valve body comes into contact with the valve seat, and the inlet port and the outlet port are again disconnected. Next, since the pressure in the tank chamber and the second valve chamber becomes equal, the fluid in the second valve chamber is caused to enter the tank chamber via the second throttle passage until the piston contacts the stopper by the spring force of the second spring member. Pushed in.

  The pilot actuated solenoid valve according to the first aspect of the present invention may further include a cover that is mounted on the valve body and defines a tank chamber between the piston and the piston.

  The second spring member may be a bellows having one end joined to the piston and the other end joined to the valve body. In this case, it is possible to further include a second stopper that restricts the movement of the piston in the direction away from the stopper. The bellows, the piston, and the valve main body may be joined by any joining method that can reliably seal against a fluid, such as laser welding, ring projection welding, or soldering.

  It is also possible to form the piston with a fluid-permeable porous material, for example, a metal wire mesh laminated or continuous foamed metal, and use the fluid permeability of the porous material itself as the second throttle passage. is there. From the same viewpoint, the first throttle passage formed in the valve body may be formed of a porous material.

  The reciprocating direction of the valve body can intersect the reciprocating direction of the valve body of the pilot valve that opens and closes the pilot flow path.

  According to a second aspect of the present invention, a compressor that compresses a refrigerant in a gas phase state, a condenser that liquefies the refrigerant in a gas phase state compressed by the compressor, and a pressure of the refrigerant liquefied by the condenser are obtained. An expansion valve for lowering, an evaporator for vaporizing the liquid-phase refrigerant that has passed through the expansion valve, a refrigerant circulation passage that sequentially passes through the compressor, the condenser, the expansion valve, and the evaporator, the condenser, and the expansion valve And a pilot-operated solenoid valve according to the first embodiment of the present invention incorporated in the middle of the circulation passage, and an inlet port of the pilot-actuated solenoid valve communicates with the circulation passage on the condenser side. The heat exchange system is characterized in that an outlet port communicates with the circulation passage following the expansion valve.

  In the present invention, the refrigerant in the gas phase state is compressed by the compressor, and the compressed refrigerant is liquefied by the condenser, where the first heat exchange is performed with the outside. The refrigerant in the liquid phase is lowered in pressure by the expansion valve and vaporized again by the evaporator, where the second heat exchange is performed with the outside. When the pilot valve of the pilot operated solenoid valve closes the pilot flow path, the circulation path between the condenser and the expansion valve is blocked. From this state, the pilot valve When the passage is opened, the valve body first moves slightly and high-pressure refrigerant gradually flows from the inlet port to the outlet port toward the expansion valve, and then the valve body is completely separated from the valve seat to enter the inlet port and the outlet port. The port is in maximum communication.

  According to the pilot-operated solenoid valve of the present invention, an inlet port and an outlet port are formed, and a valve main body formed on the inside with a cavity communicating with the inlet port and the outlet port is reciprocally accommodated in the cavity. A valve body that partitions the cavity into a first valve chamber and a second valve chamber side in which the inlet port and the outlet port communicate with each other, and can contact a valve seat formed at the outlet port so as to face the first valve chamber, A first throttle passage formed in the valve body and communicating between the first valve chamber and the second valve chamber, and attached to the second valve chamber side so as to be capable of reciprocating along the opposing direction of the valve body. A piston that divides the two-valve chamber side into a second valve chamber and a tank chamber; a first spring member that is interposed between the piston and the valve body and energizes the pistons so as to widen them; and Formed to communicate between the second valve chamber and the tank chamber A second throttle passage, a stopper formed in the cavity and defining a gap formed between the valve body and the piston in a state where the valve body is in contact with the valve seat, and the piston toward the stopper Since it comprises a second spring member to be urged, a pilot passage formed in the valve body and communicating the outlet port and the second valve chamber, and a pilot valve for opening and closing the pilot passage, When the pilot flow path is opened by the pilot valve, after the valve body abuts on the piston and the valve body is slightly separated from the valve seat, the fluid in the tank chamber is piloted from the second valve chamber through the second throttle passage. Since the valve body moves in a direction away from the valve seat together with the piston while being discharged to the outlet port side through the flow path, the fluid can flow out from the outlet port relatively slowly. As a result, the pressure increase of the fluid on the outlet port side due to the valve opening operation of the valve body occurs relatively slowly in two stages, so that damage to the fluid device connected to the downstream side of the outlet port can be prevented in advance. .

  When a cover that defines a tank chamber between the piston and the piston is mounted on the valve body, the internal volume of the tank chamber can be changed by using a cover having a different size. In combination with changing the dimensional shape of the throttle passage, it is possible to arbitrarily set the valve opening moving speed of the valve body. If the slowdown time is not required, it can be deleted.

  When a bellows having one end joined to the piston and the other end joined to the valve body is used as the second spring member, the seal mechanism between the piston and the valve body is used as the second spring member. Therefore, the number of parts can be reduced. In particular, when a second stopper that restricts the movement of the piston in the direction away from the stopper is further provided, it is possible to prevent the bellows from being damaged due to compression deformation.

  When the piston is formed of a fluid-permeable porous material and the fluid permeability of the porous material itself is used as the second throttle passage, it is not necessary to machine the second throttle passage, reducing the number of processing steps. Can be reduced.

  When the reciprocating direction of the valve body and the reciprocating direction of the valve body of the pilot valve that opens and closes the pilot flow path intersect, the interference between the pilot valve and the tank chamber can be avoided. It becomes possible to set arbitrarily, and the valve opening moving speed of the valve body can be set more freely.

  According to the heat exchange system of the second aspect of the present invention, the compressor that compresses the gas-phase refrigerant, the condenser that liquefies the gas-phase refrigerant compressed by the compressor, and the liquefaction by the condenser. An expansion valve that lowers the pressure of the refrigerant, an evaporator that vaporizes the liquid-phase refrigerant that has passed through the expansion valve, a refrigerant circulation passage that sequentially passes through the compressor, the condenser, the expansion valve, and the evaporator, and the condensation And a pilot-operated solenoid valve according to the first embodiment of the present invention incorporated in the middle of a circulation passage connecting the condenser and the expansion valve, and the inlet port of this pilot-actuated solenoid valve is communicated with the circulation passage on the condenser side At the same time, the outlet port communicates with the circulation passage that follows the expansion valve, so that the refrigerant pressure change that occurs when the pilot-operated solenoid valve is opened can be performed slowly, resulting in shocking changes in the refrigerant pressure. Accompanied by Damage arranged inflation valve downstream of the pilot operated solenoid valve can be made can either be prevented.

  An embodiment in which the heat exchange system according to the present invention is applied to an air conditioner will be described in detail with reference to FIGS. 1 to 7. However, the present invention is not limited to such an embodiment, and the claims Any change or modification included in the concept of the present invention described in the above is possible, and can naturally be applied to any other technique belonging to the spirit of the present invention.

  The concept of the air conditioner in this embodiment is shown in FIG. The air conditioner 10 in this embodiment includes a compressor 11 that compresses a gas-phase refrigerant to a high pressure, an outdoor heat exchanger 13 that communicates with the compressor 11 via a refrigerant supply pipe 12, and an outdoor heat exchanger 13. The indoor heat exchanger 16 that communicates with the compressor 11 via the refrigerant return pipe 15 and the refrigerant heat return pipe 15 connects the indoor heat exchanger 16 and the outdoor heat exchanger 13. 14 is provided with an expansion valve 17 incorporated in the middle of 14 and a pilot-operated electromagnetic valve 18 incorporated in the middle of the refrigerant circulation pipe 14 between the expansion valve 17 and the outdoor heat exchanger 13. In addition, the outdoor heat exchanger 13 as a condenser in the present invention is provided with a cooling fan 19 for cooling the refrigerant having a high temperature, and the indoor heat exchanger 16 as an evaporator in the present invention has an indoor A circulation fan 20 is provided for guiding the air to the indoor heat exchanger 16 and sending it out into the room again. Further, based on detection signals from temperature sensors and pressure switches (not shown) and commands from the operation switches, the compressor 11, the outdoor heat exchanger 13, the indoor heat exchanger 16, the expansion valve 17, and the pilot operated solenoid valve 18 are controlled. A control device (not shown) for controlling the operation is also provided.

  The compressor 11 is controlled to be driven and stopped based on the indoor temperature at which the indoor heat exchanger 16 is disposed. However, the compressor 11 is driven and stopped directly according to the refrigerant pressure in the indoor heat exchanger 16. It has become.

  The expansion valve 17 is a valve opening variable position that adiabatically expands and changes to a low-temperature and low-pressure state without causing a phase change of the refrigerant passing through the expansion valve 17 and simply allows the refrigerant to pass therethrough without acting on the refrigerant. And an open position.

  When the indoor temperature falls below a preset temperature, the pilot-operated solenoid valve 18 is closed to close the refrigerant circulation pipe 14, and the indoor heat from the outdoor heat exchanger 13 through the expansion valve 17. The refrigerant is prevented from flowing to the exchanger 16 side. In this state, the compressor 11 continues to operate, collects the refrigerant in the indoor heat exchanger 16 in the outdoor heat exchanger 13, and thus the pressure in the indoor heat exchanger 16 has dropped to a predetermined pressure. The compressor 11 is stopped. On the other hand, when the room temperature rises higher than a preset temperature, the pilot-operated solenoid valve 18 is opened and the refrigerant is circulated from the outdoor heat exchanger 13 to the indoor heat exchanger 16, As a result, the pressure in the indoor heat exchanger 16 rises. As a result, the compressor 11 is activated and the refrigerant circulates in the direction of the arrow in FIG. 1, and the low-temperature and low-pressure refrigerant passing through the indoor heat exchanger 16 and the room air. Heat is exchanged between the two, and the room is cooled.

  Thus, when the compressor 11 is in a stopped state, the pilot operated solenoid valve 18 is closed and the refrigerant does not flow into the indoor heat exchanger 16 having a low temperature and pressure. It is possible to prevent such a problem that the heat exchanger 16 condenses and liquefies, and the compressor 11 is damaged when restarted. Further, in the present embodiment, as the pilot operated solenoid valve 18 is opened, the high pressure refrigerant interposed upstream of the pilot operated solenoid valve 18 acts as an impact pressure on the expansion valve 17. In order to avoid this, the opening operation of the pilot operated solenoid valve 18 is performed relatively slowly.

  FIG. 2 shows a cross-sectional structure of the pilot operated solenoid valve 18 in this embodiment, and FIG. 3 to FIG. That is, the pilot operated solenoid valve 18 in the present embodiment is a so-called normally closed electromagnetic drive type that is closed when not energized, and the tubular valve body 21 includes a first valve. A cavity for defining the chamber 22a, the second valve chamber 22b, and the tank chamber 22c along the first direction (vertical direction in FIG. 2) is formed inside thereof. The cavity in the present embodiment includes a small-diameter portion that extends along the first direction and defines the peripheral side wall of the first valve chamber 22a, and a piston 23 that extends along the first direction and will be described later. It has a large-diameter portion for accommodating and a step portion 24 defined between them.

  The valve body 21 includes an inlet port 25 that extends in a second direction (left-right direction in FIG. 2) intersecting the first direction and communicates with the first valve chamber 22a, and a first direction. And an outlet port 27 having a valve seat 26 facing the first valve chamber 22a. The inlet and outlet ports 25 and 27 are fitted with pipe joints 28 and 29 connected to the refrigerant circulation pipe 14, respectively. The inlet port 25 communicates with the outdoor heat exchanger 13 and the outlet port 27 is connected to the outlet and outlet ports 25 and 27. It is in a state of communicating with the expansion valve 17 side.

  The pilot flow path 30 formed in the valve body 21 along the small diameter portion of the cavity so that one end is opened at a part of the stepped portion 24 and the other end is opened at the outlet port 27 is an outlet port 27 of the valve body 21. Opening and closing of the valve is controlled by a pilot valve 31 attached to the side of the valve. The pilot valve 31 in the present embodiment is a normally closed type electromagnetic valve, and includes a coil 32 for turning on / off current, a plunger 34 having a ball 33 for opening and closing the pilot flow path 30 at the tip, and this plunger. A compression spring 35 that biases the plunger 34 toward the pilot flow path 30 is provided so that the balls 33 of the 34 close the pilot flow path 30. Accordingly, when the coil 32 of the pilot valve 31 is energized, the plunger 34 is excited so that the ball 33 is separated from the pilot flow path 30 against the spring force of the compression spring 35, and the pilot flow path 30 is thereby opened. It becomes.

  As for the configuration of the pilot valve 31 that opens and closes the pilot flow path 30, any one other than the present embodiment can be adopted as appropriate.

  A valve body 36 having a tip that can contact the valve seat 26 of the outlet port 27 is slidably fitted along the first direction in the small-diameter portion of the cavity, and the small-diameter portion of the cavity is connected to the first valve. The chamber 22a is partitioned from the second valve chamber 22b side. The valve body 36 in the present embodiment whose tip is smaller in diameter than the small-diameter portion of the cavity includes a cylindrical portion 36a that protrudes on the opposite side of the valve seat 26 and is in sliding contact with the small-diameter portion of the cavity. A communication passage 36b formed so as to cross the distal end in the radial direction and having both ends open to the first valve chamber 22a, and one end opening to the communication passage 36b and the other end inside the cylindrical portion 36a, that is, the second valve A first throttle passage 37 that opens to the chamber 22b side is formed. In the state shown in FIG. 2 in which the distal end portion of the valve body 36 completely closes the valve seat 26, the cylindrical portion is formed such that a gap is formed between the distal end of the cylindrical portion 36a and the step portion 24. A projecting length of 36a is set. The gap of the predetermined interval corresponds to the first stage lift amount of the valve body 36.

  One open end of a bellows 38 extending along the first direction is joined to the piston 23 accommodated in the large-diameter portion of the cavity so as to be reciprocating along the first direction by brazing or the like. Similarly, the other open end of the cylindrical bellows 38 is joined to the outer edge of an annular guide bracket 39 attached to the end of the valve body 21 opposite to the outlet port 27 by brazing or the like. ing. The guide bracket 39 is integrally joined to the end of the valve body 21 opposite to the outlet port 27 by brazing or the like, together with a cover 40 having a cup-shaped cross section that closes the open end of the large-diameter portion of the cavity. Therefore, the piston 23 and the bellows 38 define a second valve chamber 22b between the piston body 36 and the valve body 36, and a tank chamber 22c between the cover 40 and the second valve chamber 22b and the tank chamber 22c. Is formed in the central portion of the piston 23. The bellows 38 in the present embodiment is extendable in the first direction, and the second spring of the present invention has an urging force that presses the piston 23 against the stepped portion 24 of the cavity, that is, the stopper in the present invention. It also functions as a member. The guide bracket 39 is formed with a cylindrical second stopper 39a that protrudes toward the piston 23 so that the bellows 38 is sandwiched between the peripheral wall of the large-diameter portion of the cavity. The displacement of the piston 23 in the direction of separating, that is, the direction in which the bellows 38 contracts can be regulated. As a result, the piston 23 is displaced between the stepped portion 24 and the second stopper 39a, and the stroke of the piston 23 corresponds to the second stage lift amount of the valve body 36.

  In the present embodiment, the bellows 38 is used to seal the piston 23 and the large-diameter portion of the cavity of the valve body 21, but the outer peripheral surface of the piston 23 is slidably attached to the peripheral side wall of the large-diameter portion of the cavity. A compression spring may be incorporated between the piston 23 and the guide bracket 39.

  A compression spring 42 is provided between the valve body 36 and the piston 23 as a first spring member in the present invention so as to increase the distance between the valve body 36 and the piston 23. The compression spring 42 is disposed inside the cylindrical portion 36a. It is in a state of being accommodated in. The cavity step portion 24 is formed with a communication groove 24 a extending radially inward from one end of the pilot flow path 30 and communicating with the small diameter portion of the cavity, and the piston 23 is in contact with the step portion 24. In this case, the pilot flow path 30 communicates with the second valve chamber 22b. Similarly, when the tip of the cylindrical portion 36a of the valve body 36 is in contact with the piston 23, the pilot flow path 30 and the second valve chamber 22b in the cylindrical portion 36a of the valve body 36 are connected via the communication groove 24a. A radial notch 43 is formed at the tip of the cylindrical portion 36a of the valve body 36 so as to communicate with each other, and an annular gap is formed between the peripheral wall of the small diameter portion of the cavity by chamfering the outer peripheral surface side. is doing.

  Due to such a configuration, when the coil 32 of the pilot valve 31 is in a non-energized state, the ball 33 of the plunger 34 is in a state of closing the pilot flow path 30 by the spring force of the compression spring 35. For this reason, the refrigerant flowing into the first valve chamber 22a from the inlet port 25 is also supplied from the communication passage 36b to the second valve chamber 22b via the first throttle passage 37, and finally the first valve chamber 22b. The refrigerant pressures in 22a, the second valve chamber 22b, and the tank chamber 22c become equal. As a result, the tip of the valve body 36 is pressed against the valve seat 26 by the spring force of the compression spring 42 to close the outlet port 27, and the piston 23 is pressed against the stepped portion 24 by the spring force of the bellows 38 in FIG. As shown. In this state, the flow of the refrigerant from the inlet port 25 side to the outlet port 27 side is blocked, and the refrigerant circulation pipe 14 between the outdoor heat exchanger 13 and the expansion valve 17 is closed.

  When the coil 32 of the pilot valve 31 is energized from this state, the plunger 34 is excited so that the ball 33 is separated from the pilot flow path 30, the pilot flow path 30 is opened, and the pressure in the second valve chamber 22b is adjusted to the communication groove 24a. It is possible to escape to the outlet port 27 side through the pilot flow path 30. For this reason, the pressure of the refrigerant in the first valve chamber 22a overcomes the spring force of the compression spring 42, and the valve body 36 is lifted to the first stage where the tip of the cylindrical portion 36a of the valve body 36 contacts the piston 23. A part of the refrigerant in the two-valve chamber 22b flows out from the pilot flow path 30 to the outlet port 27 through the cutout 43 at the tip of the cylindrical portion 36a and the communication groove 24a. As a result, a slight gap is formed between the valve seat 26 and the tip of the valve body 36, and the state is switched to the state shown in FIG.

  Since the tank chamber 22c communicates with the second valve chamber 22b via the second throttle passage 41, the pressure of the refrigerant in the tank chamber 22c gradually decreases in the state shown in FIG. When the pressure in the tank chamber 22c becomes substantially equal to the pressure in the second valve chamber 22b, the pressure in the first valve chamber 22a overcomes the spring force of the compression spring 42 and bellows 38, and the piston 23 contacts the second stopper 39a. The valve body 36 is lifted together with the piston 23 until the second stage of contact. As a result, a part of the refrigerant in the tank chamber 22c flows out from the pilot flow path 30 to the outlet port 27 through the notch 43 and the communication groove 24a of the cylindrical portion 36a. A large gap is formed between the leading end and the state as shown in FIG. 4 from which a large amount of refrigerant flows to the outlet port 27. In this case, the moving speed of the valve body 36 is in a slow state almost dependent on the outflow speed of the refrigerant pushed out from the tank chamber 22c to the second valve chamber 22b, and the pilot operated solenoid valve 18 is opened. The refrigerant flows into the expansion valve 17 relatively gently after the valve body 36 starts to be detached from the valve seat 26. As a result, the rate of increase in the pressure of the refrigerant acting on the expansion valve 17 becomes slow, and damage to the expansion valve 17 due to the opening operation of the pilot operated solenoid valve 18 can be prevented.

  When the coil 32 of the pilot valve 31 is returned to the non-energized state from this state, the ball 33 of the plunger 34 is closed by the spring force of the compression spring 35, and the refrigerant in the first valve chamber 22a is discharged. Supply from the communication passage 36b through the first throttle passage 37 into the second valve chamber begins. When the pressure in the second valve chamber 22b becomes substantially equal to the pressure in the first valve chamber 22a, the valve body 36 is pushed back toward the valve seat 26 by the spring force of the compression spring 35, and the valve body 36 is returned to the valve seat 26. 5 is brought into a state shown in FIG. Further, from this state, the refrigerant in the second valve chamber 22b is supplied to the tank chamber 22c through the second throttle passage 41, and finally the piston 23 is pressed against the step portion 24 by the spring force of the bellows 38, Returning to the state shown in FIG.

FIG. 6 schematically shows a change over time in the lift amount of the valve element 36 accompanying the opening operation of the pilot operated solenoid valve 18 described above. The time T ₁ required for the valve body 36 to lift in the first stage mainly depends on the passage sectional area of the first throttle passage 37. Further, the time from when the valve body 36 performs the first stage lift to the start of the second stage lift (T ₂ −T ₁ ) and the time required for the valve body 36 to perform the second stage lift (T ₃ −T). ₂ ) depends on the capacity of the tank chamber 22 c and / or the passage sectional area of the second throttle passage 41. In this embodiment, since the reciprocating direction of the valve body 36 and the piston 23 is performed along the first direction orthogonal to the reciprocating direction of the plunger 34 of the pilot valve 31, the coil of the pilot valve 31 is used. Since mechanical interference between the cover 32 and the cover 40 can be completely avoided, the cover 40 having an arbitrary volume can be joined to the valve body 21. Thus, the capacity of the tank chamber 22c, that is, the size of the cover 40 can be freely changed. In combination with the change of the inner diameter of the second throttle passage 41, the opening of the valve body 36 at the time of valve opening is possible. The valve speed can be adjusted arbitrarily. FIG. 7 schematically shows the relationship between the capacity of the tank chamber 22c and the valve opening time required until the valve element 36 shown in FIG. 4 is fully opened. This is because the inner diameter of the second throttle passage 41 is 0.5 mm. It will be understood that the valve opening time can be set longer as the capacity of the tank chamber 22c is increased.

It is a conceptual diagram of one Embodiment which applied the heat exchange system by this invention to the air conditioning apparatus. It is a longitudinal cross-sectional view showing the structure of one Embodiment of the pilot actuated solenoid valve by this invention integrated in the air conditioning apparatus shown in FIG. 1, and has shown the state which the pilot valve has blocked the pilot flow path. FIG. 3 is an enlarged cross-sectional view of a main part of the pilot operated solenoid valve shown in FIG. 2, showing a state immediately after the pilot valve opens the pilot flow path from the state of FIG. 2. It is an expanded sectional view of the principal part of the pilot actuated solenoid valve shown in FIG. 2, and shows a state in which the valve body and the piston are further moved from the state of FIG. FIG. 5 is an enlarged cross-sectional view of the main part of the pilot operated solenoid valve shown in FIG. 2, showing a state immediately after the pilot valve blocks the pilot flow path from the state of FIG. 4. FIG. 5 is a graph schematically showing a change with time of the lift amount of the valve body when the pilot valve opens the pilot flow path from the state of FIG. 2 and shifts to the state of FIG. 4. 5 is a graph schematically showing a change in valve opening time from the fully closed state of FIG. 2 to the fully opened state of FIG. 4 when the capacity of the tank chamber of the pilot operated solenoid valve shown in FIG. 2 is changed.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Air conditioning apparatus 11 Compressor 12 Refrigerant supply pipe 13 Outdoor heat exchanger 14 Refrigerant circulation pipe 15 Refrigerant return pipe 16 Indoor heat exchanger 17 Expansion valve 18 Pilot actuated solenoid valve 19 Cooling fan 20 Circulating fan 21 Valve body 22a First 1 Valve chamber 22b Second valve chamber 22c Tank chamber 23 Piston 24 Stepped portion 24a Communication groove 25 Inlet port 26 Valve seat 27 Outlet port 28, 29 Piping joint 30 Pilot flow path 31 Pilot valve 32 Coil 33 Ball 34 Plunger 35 Compression spring 36 Valve body 36a Cylindrical portion 36b Communication passage 37 First throttle passage 38 Bellows 39 Guide bracket 39a Second stopper 40 Cover 41 Second throttle passage 42 Compression spring 43 Notch T ₁ First stage lift end time T ₂ Second stage of the start time T ₃ the second stage of the riff of lift End time of

Claims (7)

A valve body in which an inlet port and an outlet port are formed, and a cavity communicating with the inlet port and the outlet port is formed inside;
The cavity is accommodated in a reciprocating manner so that the cavity is divided into a first valve chamber and a second valve chamber side in which the inlet port and the outlet port communicate with each other, and the outlet port is provided so as to face the first valve chamber. A valve body capable of contacting the formed valve seat;
A first throttle passage formed in the valve body and communicating the first valve chamber and the second valve chamber;
A piston which is attached to the second valve chamber side so as to be capable of reciprocating along the direction facing the valve body, and which partitions the second valve chamber side into a second valve chamber and a tank chamber;
A first spring member that is interposed between the piston and the valve body and biases the gap between them,
A second throttle passage formed in the piston and communicating the second valve chamber and the tank chamber;
A stopper that defines a gap formed between the valve body and the piston when the valve body is in contact with the valve seat, and formed in the cavity.
A second spring member that biases the piston toward the stopper;
A pilot passage formed in the valve body and communicating the outlet port and the second valve chamber;
A pilot operated solenoid valve, comprising: a pilot valve for opening and closing the pilot flow path.   The pilot operated solenoid valve according to claim 1, further comprising a cover mounted on the valve body and defining the tank chamber with the piston.   The pilot-operated solenoid valve according to claim 1 or 2, wherein the second spring member is a bellows having one end joined to the piston and the other end joined to the valve body. .   The pilot operated solenoid valve according to claim 3, further comprising a second stopper for restricting movement of the piston in a direction away from the stopper.   5. The method according to claim 1, wherein the piston is formed of a fluid-permeable porous material, and the second throttle passage uses the fluid permeability of the porous material itself. A pilot operated solenoid valve according to claim 1.   The pilot according to any one of claims 1 to 5, wherein a reciprocating direction of the valve body intersects a reciprocating direction of a valve body of the pilot valve that opens and closes the pilot flow path. Actuated solenoid valve. A compressor for compressing a refrigerant in a gas phase;
A condenser for liquefying the gas-phase refrigerant compressed by the compressor;
An expansion valve that reduces the pressure of the refrigerant liquefied by the condenser;
An evaporator that vaporizes the liquid-phase refrigerant that has passed through the expansion valve;
A refrigerant circulation path that passes through the compressor, condenser, expansion valve, and evaporator in sequence,
The pilot operated solenoid valve according to any one of claims 1 to 6, wherein the pilot operated solenoid valve is incorporated in the middle of the circulation passage connecting the condenser and the expansion valve. A heat exchange system, wherein the heat exchanger system communicates with the circulation passage on the condenser side, and an outlet port communicates with the circulation passage following the expansion valve.

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