JP2012002251A - Control valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the use efficiency of a fluid introduced into a back pressure chamber, in a pilot-operated control valve.SOLUTION: A compound valve 35 is constituted by integrating a changeover valve 31 and a check valve 32. The changeover valve 31 is a control valve employing a pilot operation system, which controls a main valve 105 to open and close it, by opening or closing a pilot valve 106 to change the pressure of a refrigerant in a back pressure chamber 152. When the refrigerant is led out from the back pressure chamber 152, a pilot valve body 170 decreases the opening of a pilot valve hole 140 that acts as a leading passage of the refrigerant from the back pressure chamber 152 and throttles the opening of a leakage passage 166 that acts as an introducing passage of the refrigerant to the back pressure chamber 152.

Description

  The present invention relates to a pilot operated control valve that controls opening and closing of a main valve by opening and closing the pilot valve.

  Generally, an air conditioner for an automobile is configured by arranging a compressor, a condenser, an evaporator, and the like in a refrigerant circulation passage (see, for example, Patent Document 1). For example, a branch point between a passage through which the refrigerant passes and a passage through which the refrigerant passes is provided between the compressor and the condenser. The air conditioning control is performed by changing the state (temperature) of the refrigerant sent to the evaporator by forming a passage mainly for passing the condenser during the cooling operation and mainly forming a passage for bypassing the condenser during the heating operation. ing. In order to perform such control, a switching valve for switching the refrigerant flow between the cooling operation and the heating operation is provided at the branch point.

  In the air conditioner described in Patent Document 1, a three-way switching valve that selectively connects the upstream passage to one of the two downstream passages is provided. This switching valve has a main valve body that opens one valve portion with one solenoid and simultaneously closes the other valve portion. Moreover, the main valve body is a pilot-operated type, so that the entire valve is made compact.

JP-A-11-287354

  By the way, such a pilot-actuated control valve controls the opening and closing of the main valve by changing the pressure in the back pressure chamber by opening and closing the pilot valve. The pressure in the back pressure chamber is adjusted by the balance between the flow rate of the refrigerant introduced into the back pressure chamber and the flow rate of the refrigerant derived from the back pressure chamber. That is, in order to maintain the open / closed state of the main valve, introduction of the refrigerant from the upstream side to the back pressure chamber and derivation of the refrigerant from the back pressure chamber to the downstream side are continued. Therefore, there is a useless phenomenon in which a refrigerant that does not directly contribute to the opening / closing operation of the main valve is introduced into the back pressure chamber and led out as it is, and there is room for improvement in terms of the operating efficiency of the compressor.

  One of the objects of the present invention is to increase the utilization efficiency of the fluid introduced into the back pressure chamber in the pilot operated control valve.

  In order to solve the above problems, a control valve according to an aspect of the present invention is a pilot operated control valve that controls opening and closing of a main valve by changing the pressure of a back pressure chamber by opening and closing of the pilot valve. A mechanism is provided for reducing the opening of the introduction passage for introducing the fluid into the pressure chamber and for reducing the opening of the outlet passage for extracting the fluid from the back pressure chamber.

  According to this aspect, when maintaining the pressure of the back pressure chamber in the pilot-actuated control valve, the opening degree of the fluid introduction passage to the back pressure chamber is reduced, and the fluid outlet passage from the back pressure chamber is reduced. The opening of is reduced. For this reason, in order to maintain the pressure of a back pressure chamber, the flow volume of the fluid which passes a pilot valve can be controlled, and the utilization efficiency of a fluid can be improved.

  ADVANTAGE OF THE INVENTION According to this invention, the utilization efficiency of the fluid introduce | transduced into a back pressure chamber can be improved in a pilot actuated control valve.

1 is a system configuration diagram illustrating a schematic configuration of a vehicle air conditioner. It is explanatory drawing showing operation | movement of the vehicle air conditioner. It is sectional drawing showing the specific structure and operation | movement of a composite valve. It is explanatory drawing showing operation | movement of a compound valve. It is explanatory drawing showing operation | movement of a compound valve. It is explanatory drawing showing operation | movement of a compound valve. It is explanatory drawing showing operation | movement of a compound valve. It is explanatory drawing showing operation | movement of a compound valve. It is explanatory drawing showing operation | movement of a compound valve. It is sectional drawing showing the specific structure and operation | movement of a superheat degree control valve.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a system configuration diagram illustrating a schematic configuration of a vehicle air conditioning apparatus according to an embodiment. In the present embodiment, the vehicle air conditioning apparatus of the present invention is embodied as an electric vehicle air conditioning apparatus.

  The vehicle air conditioner 1 includes a refrigeration cycle in which a compressor 2, an indoor condenser 3, a first control valve unit 4, an outdoor heat exchanger 5, a second control valve unit 6, an evaporator 7 and an accumulator 8 are connected by piping. (Refrigerant circuit). The vehicle air conditioner 1 is a heat pump type air conditioner that performs air conditioning in the vehicle interior using the heat of the refrigerant in a process in which alternative refrigerant (HFC-134a) as a refrigerant circulates while changing its state in the refrigeration cycle. It is configured as.

  The vehicle air conditioner 1 is also operated so as to switch a plurality of refrigerant circulation passages between the cooling operation and the heating operation. The refrigeration cycle is configured such that the indoor condenser 3 and the outdoor heat exchanger 5 can operate in parallel as a condenser, and the evaporator 7 and the outdoor heat exchanger 5 can operate in parallel as an evaporator. It is configured. That is, a first refrigerant circulation passage through which the refrigerant circulates during the cooling operation and the heating operation, a second refrigerant circulation passage through which the refrigerant circulates only during the heating operation, and a third refrigerant circulation passage through which the refrigerant circulates only during the cooling operation are formed. .

  The first refrigerant circulation passage is a passage through which the refrigerant circulates as follows: compressor 2 → indoor condenser 3 → second control valve unit 6 → evaporator 7 → accumulator 8 → compressor 2. The second refrigerant circulation passage is a passage through which the refrigerant circulates like the compressor 2 → the indoor condenser 3 → the second control valve unit 6 → the outdoor heat exchanger 5 → the first control valve unit 4 → the accumulator 8 → the compressor 2. It is. The third refrigerant circulation passage is a passage through which the refrigerant circulates like the compressor 2 → the first control valve unit 4 → the outdoor heat exchanger 5 → the second control valve unit 6 → the evaporator 7 → the accumulator 8 → the compressor 2. is there. The refrigerant flow through the outdoor heat exchanger 5 is reversed between when the second refrigerant circulation passage is opened and when the third refrigerant circulation passage is opened. That is, the refrigerant inlet and outlet in the outdoor heat exchanger 5 are switched between when the second refrigerant circulation passage is opened and when the third refrigerant circulation passage is opened.

  Specifically, a passage leading to the discharge chamber of the compressor 2 is branched, one of the first passages 21 is connected to the inlet of the indoor condenser 3, and the other second passage 22 is connected to the outdoor heat exchanger 5. Connected to one doorway. The third passage 23 connected to the outlet of the indoor condenser 3 branches on the downstream side thereof, and the first branch passage 26 on one side thereof is connected to the evaporator 7 via the fourth passage 24 and the second branch on the other side. The passage 27 is connected to the other entrance / exit of the outdoor heat exchanger 5 through the fifth passage 25. The fourth passage 24 and the fifth passage 25 are connected by a connection passage 28. In addition, a bypass passage 29 is branched at an intermediate portion of the second passage 22 and is connected to the accumulator 8 and the compressor 2. Further, a return passage 30 connected to the outlet of the evaporator 7 is connected to the bypass passage 29 and downstream of a check valve 32 (described later), and is connected to the accumulator 8 and the compressor 2.

  The first refrigerant circulation passage is configured by connecting the first passage 21, the third passage 23, the first branch passage 26, the fourth passage 24, and the return passage 30. The second refrigerant circulation passage is configured by connecting the first passage 21, the third passage 23, the second branch passage 27, the fifth passage 25, the second passage 22, and the bypass passage 29. The third refrigerant circulation passage is configured by connecting the second passage 22, the fifth passage 25, the connection passage 28, the fourth passage 24, and the return passage 30. And in order to implement | achieve such switching of a refrigerant circulation path, the 1st control valve unit 4 is provided in the connection part of the compressor 2 and the outdoor heat exchanger 5, and the indoor condenser 3 and the outdoor heat exchanger 5 are provided. A second control valve unit 6 is provided at the connection between the evaporator 7 and the evaporator 7.

  The vehicle air conditioner 1 has a duct 10 in which heat exchange of air is performed, and an indoor blower 12, an evaporator 7, and an indoor condenser 3 are arranged from the upstream side of the air flow direction in the duct 10. An air mix door 14 is rotatably provided on the upstream side of the indoor condenser 3, and the ratio between the air volume passing through the indoor condenser 3 and the air volume bypassing the indoor condenser 3 is adjusted. Moreover, the outdoor air blower 16 is arrange | positioned so that the outdoor heat exchanger 5 may be opposed.

  The compressor 2 is configured as an electric compressor that houses a motor and a compression mechanism in a housing, is driven by a supply current from a battery (not shown), and the discharge capacity of the refrigerant changes according to the rotational speed of the motor. As this compressor 2, various types of compressors such as a reciprocating type, a rotary type and a scroll type can be adopted. However, since the electric compressor itself is publicly known, the description thereof is omitted.

  The indoor condenser 3 is provided in the vehicle interior and functions as an auxiliary condenser that dissipates the refrigerant separately from the outdoor heat exchanger 5. That is, the high-temperature and high-pressure refrigerant discharged from the compressor 2 dissipates heat when passing through the indoor condenser 3. The air distributed according to the opening degree of the air mix door 14 undergoes heat exchange in the process of passing through the indoor condenser 3.

  The outdoor heat exchanger 5 is disposed outside the passenger compartment and functions as an outdoor condenser that radiates the refrigerant that passes through the interior during the cooling operation, and functions as an outdoor evaporator that evaporates the refrigerant that passes through the interior during the heating operation. The outdoor blower 16 is a suction type blower, and introduces outside air by rotationally driving an axial fan with a motor. The outdoor heat exchanger 5 exchanges heat between the outside air and the refrigerant.

  The evaporator 7 is arrange | positioned in a vehicle interior, and functions as an indoor evaporator which evaporates the refrigerant | coolant which passes the inside. That is, the refrigerant that has become low temperature and low pressure by passing through each control valve (described later) constituting the second control valve unit 6 evaporates when passing through the evaporator 7. The air introduced from the upstream side of the duct 10 is cooled by the latent heat of vaporization. At this time, the cooled and dehumidified air is distributed into one that passes through the indoor condenser 3 and one that bypasses the indoor condenser 3 according to the opening of the air mix door 14. The air passing through the indoor condenser 3 is heated during the passage process. The air that has passed through the indoor condenser 3 and the bypassed air are mixed on the downstream side of the indoor condenser 3, adjusted to a target temperature, and supplied to the interior of the vehicle from a blower outlet (not shown). For example, the air is blown out from a vent outlet, a foot outlet, a differential outlet, or the like toward a predetermined position in the vehicle interior.

  The accumulator 8 is a device that separates and stores the refrigerant sent from the evaporator, and has a liquid phase part and a gas phase part. For this reason, even if liquid refrigerant more than expected is derived from the evaporator 7, the liquid refrigerant can be stored in the liquid phase part, and the refrigerant in the gas phase part can be derived to the compressor 2. As a result, the compression operation of the compressor 2 is not hindered. On the other hand, in the present embodiment, a part of the refrigerant in the liquid phase portion can be supplied to the compressor 2, and a necessary amount of lubricating oil can be returned to the compressor 2.

  The first control valve unit 4 includes a switching valve 31, a check valve 32 and a superheat degree control valve 33. The switching valve 31 includes a three-way electromagnetic valve that includes a first valve portion that opens and closes the second passage 22, a second valve portion that opens and closes the bypass passage 29, and a solenoid that drives each valve portion. The first valve portion allows the refrigerant to flow from the compressor 2 to the outdoor heat exchanger 5 via the second passage 22 by opening the valve. The second valve portion allows the refrigerant to flow from the outdoor heat exchanger 5 to the accumulator 8 via the bypass passage 29 by opening the valve. In the present embodiment, an on-off valve (on / off valve) that opens one of the first valve portion and the second valve portion and closes the other depending on whether the solenoid is energized is used as the switching valve 31. Note that the actuator that drives the valve portion of the switching valve 31 may not be a solenoid, but may be an electric motor such as a stepping motor. A specific configuration of the switching valve 31 will be described in detail later.

  The check valve 32 is configured as a mechanical valve that prevents the refrigerant from flowing back to the switching valve 31 side in the bypass passage 29. The check valve 32 is a differential pressure valve that autonomously opens when the front-rear differential pressure (the differential pressure between the upstream pressure and the downstream pressure of the check valve 32) exceeds a set value (a valve opening differential pressure set in advance). It may be.

  The superheat degree control valve 33 controls the flow of the refrigerant so that the superheat degree (superheat) on the outlet side of the outdoor heat exchanger 5 approaches a predetermined superheat degree (set superheat degree SH) during heating operation. It is a control valve. In the present embodiment, as the superheat degree control valve 33, a mechanical control valve having a temperature sensing unit that senses the temperature and pressure of the refrigerant on the outlet side of the outdoor heat exchanger 5 and drives the valve unit is used. The superheat degree control valve 33 reduces the opening degree of the valve if the detected degree of superheat is larger than the set superheat degree SH, and raises the evaporation pressure of the outdoor heat exchanger 5 to increase the refrigerant passing through the outdoor heat exchanger 5. The amount of heat exchange with the external air is reduced, thereby reducing the degree of superheat to approach the set superheat degree SH. On the contrary, if the detected superheat degree is smaller than the set superheat degree SH, the superheat degree control valve 33 increases the valve opening degree and reduces the evaporation pressure of the outdoor heat exchanger 5, thereby causing the outdoor heat exchanger 5 to open. The amount of heat exchange between the refrigerant passing through 5 and the external air is increased, thereby increasing the degree of superheat and bringing it closer to the set degree of superheat SH. As described above, the superheat degree control valve 33 operates autonomously so that the superheat degree on the outlet side of the outdoor heat exchanger 5 approaches the set superheat degree SH. A specific configuration of the superheat degree control valve 33 will be described in detail later.

  The second control valve unit 6 includes a supercooling degree control valve 41 (first supercooling degree control valve), a proportional valve 42, a supercooling degree control valve 43 (second supercooling degree control valve), and a check valve 44. including. The supercooling degree control valve 41 functions as an “expansion device” that squeezes and expands the refrigerant introduced from the indoor condenser 3 via the third passage 23 and leads it to the downstream side, and from the indoor condenser 3 to the evaporator. 7 and the “total flow valve” that adjusts the total flow rate of the refrigerant supplied to the outdoor heat exchanger 5.

  The supercooling degree control valve 41 is a control valve that controls the flow of the refrigerant so that the supercooling degree (subcool) on the outlet side of the indoor condenser 3 approaches a predetermined supercooling degree (set value SC1). . In the present embodiment, as the supercooling degree control valve 41, a mechanical control valve having a temperature sensing unit that senses the temperature and pressure of the refrigerant on the outlet side of the indoor condenser 3 and drives the valve unit is used. The supercooling degree control valve 41 operates in the valve opening direction when the supercooling degree on the outlet side of the indoor condenser 3 becomes larger than the set value SC1, and increases the flow rate of the refrigerant flowing through the indoor condenser 3. When the flow rate of the refrigerant increases in this way, the condensing capacity per unit flow rate of the refrigerant in the indoor condenser 3 decreases, so that the degree of supercooling decreases.

  Conversely, when the degree of supercooling on the outlet side of the indoor condenser 3 becomes smaller than the set value SC1, the supercooling degree control valve 41 operates in the valve closing direction to decrease the flow rate of the refrigerant flowing through the indoor condenser 3. . When the flow rate of the refrigerant is thus reduced, the condensation capacity per unit flow rate of the refrigerant in the indoor condenser 3 is increased, so that the degree of supercooling is increased. Thus, the supercooling degree control valve 41 operates autonomously so that the supercooling degree at the inlet (the outlet side of the indoor condenser 3) becomes the set value SC1.

  The proportional valve 42 is configured as a three-way electromagnetic proportional valve, and is provided at a branch point where the third passage 23 branches into the first branch passage 26 and the second branch passage 27. That is, the proportional valve 42 is configured as a “composite valve” including a first proportional valve that controls the opening degree of the first branch passage 26 and a second proportional valve that controls the opening degree of the second branch passage 27. Yes.

  The first proportional valve adjusts the opening degree of the first refrigerant circulation passage by controlling the opening degree of the valve portion. The second proportional valve adjusts the opening degree of the second refrigerant circulation passage by controlling the opening degree of the valve portion. The first proportional valve and the second proportional valve are integrally provided with valve bodies constituting the respective valve portions, and are linearly controlled simultaneously by one actuator. Thereby, the ratio of the opening degree of each valve part is controlled. That is, during the heating operation, the total flow rate of the refrigerant supplied to the evaporator 7 and the outdoor heat exchanger 5 is adjusted by the supercooling degree control valve 41, and the total flow rate is distributed to the ratio set by the proportional valve 42. It is done. That is, the proportional valve 42 functions as a “distribution valve” that distributes the flow rate of the refrigerant according to the drive amount of the actuator. In the present embodiment, the actuator of the proportional valve 42 is a solenoid, but in a modification, it may be a stepping motor.

  The supercooling degree control valve 43 serves as an “expansion device” that expands and expands the refrigerant introduced from the outdoor heat exchanger 5 through the fifth passage 25 and the connection passage 28 to the evaporator 7 side during cooling operation. Function. The supercooling degree control valve 43 is a control valve that controls the flow of refrigerant so that the supercooling degree on the outlet side of the outdoor heat exchanger 5 approaches a predetermined supercooling degree (set value SC2) during cooling operation. It is. In the present embodiment, as the supercooling degree control valve 43, a mechanical control valve having a temperature sensing section that drives the valve section by sensing the temperature and pressure of the refrigerant on the outlet side of the outdoor heat exchanger 5 during the cooling operation. Is used. The supercooling degree control valve 43 operates in the valve opening direction when the supercooling degree on the outlet side of the outdoor heat exchanger 5 becomes larger than the set value SC2, and increases the flow rate of the refrigerant flowing through the outdoor heat exchanger 5. When the flow rate of the refrigerant increases in this way, the condensing capacity per unit flow rate of the refrigerant in the outdoor heat exchanger 5 decreases, so that the degree of supercooling decreases.

  Conversely, when the degree of supercooling on the outlet side of the outdoor heat exchanger 5 becomes smaller than the set value SC2, the supercooling degree control valve 43 operates in the valve closing direction, and the flow rate of the refrigerant flowing through the outdoor heat exchanger 5 is reduced. Decrease. When the flow rate of the refrigerant decreases in this way, the condensation capacity per unit flow rate of the refrigerant in the outdoor heat exchanger 5 increases, so that the degree of supercooling increases. Thus, the supercooling degree control valve 43 operates autonomously so that the supercooling degree at the inlet (outlet side of the outdoor heat exchanger 5) becomes the set value SC2.

  The check valve 44 is configured as a mechanical valve that prevents the refrigerant from flowing back to the supercooling degree control valve 43 side in the connection passage 28.

  The vehicle air conditioner 1 configured as described above is controlled by the control unit 100. The control unit 100 includes a CPU that executes various arithmetic processes, a ROM that stores various control programs, a RAM that is used as a work area for data storage and program execution, an input / output interface, and the like. Signals from various sensors and switches (not shown) installed in the vehicle air conditioner 1 are input to the control unit 100. The control unit 100 calculates the control amount of each actuator in order to realize the room temperature set by the vehicle occupant, and outputs a control signal to the drive circuit of each actuator. The control unit 100 also performs drive control of the compressor 2, the indoor fan 12, the outdoor fan 16, and the air mix door 14 in addition to opening / closing control of the switching valve 31 and the proportional valve 42.

  The control unit 100 includes a drive signal output unit that outputs a pulse signal set in the drive circuit of the proportional valve 42. Specifically, a PWM output unit is provided that outputs a pulse signal having a set duty ratio, which is calculated by the control unit 100. However, since the configuration itself is a known one, a detailed description will be given. Omitted. The control unit 100 determines the set opening of the proportional valve 42 based on predetermined external information detected by various sensors such as the temperature inside and outside the vehicle interior, the temperature of the air blown from the evaporator 7, and the opening is Supply current to the solenoid so that the set opening is reached. As a modification, when the actuator of the proportional valve 42 is configured by a stepping motor, a control pulse signal is output to the stepping motor so that the opening degree becomes the set opening degree.

  By such control, as shown in the figure, the compressor 2 introduces the refrigerant having the suction pressure Ps through the suction chamber, compresses the refrigerant, and discharges it as the refrigerant having the discharge pressure Pd. At this time, the pressure in the second control valve unit 6 is as shown. That is, the upstream side of the supercooling degree control valve 41 becomes a high pressure upstream pressure p1, and the downstream side of the first proportional valve in the proportional valve 42 becomes a low pressure downstream pressure p3. Further, an intermediate pressure p2 is provided on the downstream side of the second proportional valve in the proportional valve 42 and on the upstream side of the supercooling degree control valve 43.

  Next, operation | movement of the refrigerating cycle of this embodiment is demonstrated. FIG. 2 is an explanatory diagram illustrating the operation of the vehicle air conditioner. (A) shows the state during cooling operation, (B) shows the state during heating operation, (C) shows the state during specific heating operation, and (D) shows the state during special air conditioning operation. Yes. The “cooling operation” here is an operation state in which the cooling function functions more than the heating function, and the “heating operation” is an operation state in which the heating function functions more than the cooling function. Further, the “specific heating operation” is a heating operation in which the evaporator 7 does not function (substantially no cooling function). The “special air conditioning operation” is a cooling operation and a heating operation in which the outdoor heat exchanger 5 does not function.

  The upper part of each figure shows a Mollier diagram for explaining the operation of the refrigeration cycle. The horizontal axis represents enthalpy, and the vertical axis represents various pressures. The lower part of each figure shows the operating state of the refrigeration cycle. Thick lines and arrows in the figure indicate the flow of the refrigerant, and symbols a to g correspond to those in the Mollier diagram. Further, “x” in the figure indicates that the flow of the refrigerant is blocked. The lower part of the figure corresponds to FIG. 1, but is simplified for convenience, for example, illustration of the air mix door 14 is omitted.

  As shown in FIG. 2A, during the cooling operation, in the first control valve unit 4, the first valve portion of the switching valve 31 is opened and the second valve portion is closed. On the other hand, in the second control valve unit 6, the first proportional valve of the proportional valve 42 is opened, and the second proportional valve is closed. For this reason, the bypass passage 29 is blocked, and the refrigerant discharged from the compressor 2 is guided to the outdoor heat exchanger 5. At this time, the outdoor heat exchanger 5 functions as an outdoor condenser. That is, the refrigerant discharged from the compressor 2 is circulated through the first refrigerant so as to pass through the indoor condenser 3, the supercooling degree control valve 41, the first proportional valve of the proportional valve 42, the evaporator 7, and the accumulator 8. Circulate through the passage and return to the compressor 2, and circulate through the third refrigerant circulation passage through the switching valve 31, the outdoor heat exchanger 5, the supercooling degree control valve 43, the evaporator 7, and the accumulator 8. Return to the compressor 2.

  That is, the high-temperature and high-pressure gas refrigerant discharged from the compressor 2 is condensed by passing through the indoor condenser 3 on the one hand and the outdoor heat exchanger 5 on the other hand. Then, the refrigerant passing through the indoor condenser 3 is adiabatically expanded by the supercooling degree control valve 41, and is introduced into the evaporator 7 as a cold / low pressure gas-liquid two-phase refrigerant. At this time, the supercooling degree control valve 41 autonomously adjusts the opening degree of the valve portion so that the supercooling degree on the outlet side (point c) of the indoor condenser 3 becomes the set value SC1. Since the second proportional valve of the proportional valve 42 is closed, all the refrigerant expanded by the supercooling degree control valve 41 passes through the first proportional valve of the proportional valve 42 and is supplied to the evaporator 7.

  Further, the refrigerant passing through the outdoor heat exchanger 5 is adiabatically expanded by the supercooling degree control valve 43 and is introduced into the evaporator 7 as a cold / low pressure gas-liquid two-phase refrigerant. At this time, the supercooling degree control valve 43 autonomously adjusts the opening degree of the valve portion so that the supercooling degree on the outlet side (point f) of the indoor condenser 3 becomes the set value SC2. In the present embodiment, the set values SC1 and SC2 are set equal (denoted as “SC”), but in a modified example, they may be different from each other. The refrigerant introduced into the inlet of the evaporator 7 evaporates in the process of passing through the evaporator 7 and cools the air in the passenger compartment. At this time, the refrigerant derived from the evaporator 7 is introduced into the compressor 2 through the accumulator 8, and then the lubricating oil is returned to the compressor 2.

  On the other hand, as shown in FIG. 2 (B), during the heating operation, in the first control valve unit 4, the first valve portion of the switching valve 31 is closed and the second valve portion is opened. On the other hand, in the second control valve unit 6, the first proportional valve and the second proportional valve of the proportional valve 42 are both opened, and the ratio of the opening degree of both proportional valves is adjusted, whereby the evaporator 7 and the outdoor heat exchange are adjusted. The flow rate of the refrigerant toward the vessel 5 is distributed. At this time, the outdoor heat exchanger 5 functions as an outdoor evaporator. That is, the refrigerant discharged from the compressor 2 is circulated through the first refrigerant so as to pass through the indoor condenser 3, the supercooling degree control valve 41, the first proportional valve of the proportional valve 42, the evaporator 7, and the accumulator 8. Circulating the passage and returning to the compressor 2, on the other hand, passing through the indoor condenser 3, the supercooling degree control valve 41, the second proportional valve of the proportional valve 42, the outdoor heat exchanger 5, the superheat degree control valve 33, and the accumulator 8. In this manner, the refrigerant circulates in the second refrigerant circulation passage and returns to the compressor 2.

  That is, the high-temperature and high-pressure gas refrigerant discharged from the compressor 2 is condensed through the indoor condenser 3. Then, the cold / low pressure gas-liquid two-phase refrigerant adiabatically expanded by the supercooling degree control valve 41 is distributed by the proportional valve 42, and one of the distributed refrigerant is supplied to the evaporator 7 to be evaporated and distributed. The other refrigerant thus supplied is supplied to the outdoor heat exchanger 5 to evaporate. At this time, the ratio of evaporation in both the outdoor heat exchanger 5 and the evaporator 7 is controlled by the ratio of the opening degrees of the first proportional valve and the second proportional valve. Thereby, the evaporation amount in the evaporator 7 can be secured, and the dehumidifying function can be secured. Further, the lubricating oil can be returned to the compressor 2 without being retained in the evaporator 7. In addition, since the inlet side of the supercooling degree control valve 43 is not in a supercooling state, the supercooling degree control valve 43 maintains a closed state.

  In this heating operation, it is necessary to perform the dehumidification operation satisfactorily. The outline of the dehumidification control is as follows. That is, as shown in FIG. 2 (B), the predetermined supercooling degree SC at the outlet of the indoor condenser 3 is maintained by the supercooling degree control valve 41 (point c), so that the condensing capacity in the indoor condenser 3 is maintained. Is maintained appropriately and efficient heat exchange is performed (point d). On the other hand, the state of the refrigerant at the inlet of the compressor 2 is always maintained on the saturated vapor pressure curve by the accumulator 8 (point a). On the other hand, the state of refrigerant at the outlet of the evaporator 7 (point e) changes so as to balance with the state of refrigerant at the outlet of the outdoor heat exchanger 5 (point g).

  At this time, the amount of heat absorbed from the outside in the outdoor heat exchanger 5 is adjusted by the amount of restriction of the superheat degree control valve 33. That is, when the superheat degree on the outlet side of the outdoor heat exchanger 5 becomes larger than the set superheat degree SH, the superheat degree control valve 33 operates in the valve closing direction to increase the evaporation pressure Po in the outdoor heat exchanger 5. As a result, a differential pressure Poe between the evaporation pressure Po of the outdoor heat exchanger 5 and the evaporation pressure Pe of the evaporator 7 is generated. As a result, the temperature of the refrigerant passing through the outdoor heat exchanger 5 increases and the amount of heat exchange with the outside air decreases, so the degree of superheat changes in a decreasing direction.

  On the contrary, when the superheat degree becomes smaller than the set superheat degree SH, the evaporating pressure Po in the outdoor heat exchanger 5 is lowered by operating in the valve opening direction. Thereby, the temperature of the refrigerant passing through the outdoor heat exchanger 5 is lowered and the amount of heat exchange with the outside air is increased, so that the degree of superheat changes in a direction of increasing. Thus, since the superheat degree control valve 33 operates autonomously so that the superheat degree on the outlet side of the outdoor heat exchanger 5 becomes the set superheat degree SH, the superheat degree on the outlet side of the outdoor heat exchanger 5 is excessive. It is prevented from becoming. Thereby, the temperature nonuniformity of the outdoor heat exchanger 5 can be suppressed, and the retention of the lubricating oil in the outdoor heat exchanger 5 can be prevented or suppressed.

  The control unit 100 increases the degree of opening of the second proportional valve in accordance with the rotational speed of the compressor 2 to increase the outdoor heat exchange when a preset condition is established that the lubricating oil stays in the outdoor heat exchanger 5. Circulating lubricating oil is ensured by flowing a wet refrigerant to the outlet side of the vessel 5. In that case, the superheat degree control valve 33 operates in the valve opening direction to return the superheat degree, but since there is a time lag until the temperature sensing part senses, the lubricating oil is derived together with the wet refrigerant. It becomes possible to do. In the present embodiment, an example in which the degree of superheat is generated in the outdoor heat exchanger 5 has been shown. However, when the specification is such that the degree of superheat is generated in the evaporator 7, the degree of superheat is controlled downstream of the evaporator 7. A control valve similar to the valve 33 may be provided.

  Further, as shown in FIG. 2C, during the specific heating operation, the second valve portion of the switching valve 31 is opened and the first valve portion is closed in the first control valve unit 4. On the other hand, in the second control valve unit 6, the first proportional valve of the proportional valve 42 is closed and the second proportional valve is opened. For this reason, the refrigerant does not pass through the evaporator 7, and the evaporator 7 substantially does not function. That is, only the outdoor heat exchanger 5 functions as an evaporator. That is, the refrigerant discharged from the compressor 2 passes through the second refrigerant circulation passage so as to pass through the indoor condenser 3, the second proportional valve of the proportional valve 42, the outdoor heat exchanger 5, the superheat degree control valve 33, and the accumulator 8. And return to the compressor 2. In addition, since the inlet side of the supercooling degree control valve 43 is not in a supercooling state, the supercooling degree control valve 43 maintains a closed state.

  That is, the high-temperature and high-pressure gas refrigerant discharged from the compressor 2 is condensed through the indoor condenser 3 and is adiabatically expanded by the supercooling degree control valve 41 to become a cold / low-pressure gas-liquid two-phase refrigerant. It evaporates through the heat exchanger 5. The refrigerant that has passed through the outdoor heat exchanger 5 returns to the compressor 2 through the superheat degree control valve 33 and the accumulator 8. That is, since the cold / low pressure refrigerant is not heat-exchanged in the evaporator 7, the air introduced into the passenger compartment is only heated by the indoor condenser 3. Thus, since the low-temperature and low-pressure liquid refrigerant is temporarily not supplied to the evaporator 7, the evaporator 7 is warmed by the air passing through the duct 10. When the control unit 100 determines that the external environment is extremely low according to the external temperature or the like, the control unit 100 appropriately switches from the heating operation to the specific heating operation, thereby preventing or suppressing the evaporator 7 from freezing.

  In addition, as shown in FIG. 2D, the first valve portion of the switching valve 31 is closed in the first control valve unit 4 during the special air conditioning operation. In the second control valve unit 6, the first proportional valve of the proportional valve 42 is opened and the second proportional valve is closed. For this reason, the refrigerant does not pass through the outdoor heat exchanger 5, and the outdoor heat exchanger 5 substantially does not function. That is, only the evaporator 7 is in a state of inside air circulation that functions as an evaporator. That is, the refrigerant discharged from the compressor 2 passes through the first refrigerant circulation passage through the indoor condenser 3, the supercooling degree control valve 41, the first proportional valve of the proportional valve 42, the evaporator 7, and the accumulator 8. Circulate and return to the compressor 2. At this time, the evaporation pressure Po of the outdoor heat exchanger 5 is lower than the suction pressure Ps of the compressor 2, but the check valve 44 prevents the refrigerant from flowing backward to the supercooling degree control valve 43 side. The stop valve 32 prevents the refrigerant from flowing back to the switching valve 31 side.

  That is, the high-temperature and high-pressure gas refrigerant discharged from the compressor 2 is condensed through the indoor condenser 3 and is adiabatically expanded by the supercooling degree control valve 41 to become a cold / low-pressure gas-liquid two-phase refrigerant and evaporate. It passes through the vessel 7 and is evaporated. The refrigerant that has passed through the evaporator 7 returns to the compressor 2 via the accumulator 8. The air introduced into the passenger compartment is cooled and dehumidified via the evaporator 7 and heated by the indoor condenser 3 to adjust its temperature. Such special air conditioning operation functions effectively when it is difficult to absorb heat from the outside, for example, when the vehicle is placed in an extremely cold state.

  Next, a specific configuration and operation of the first control valve unit 4 will be described. As described above, the first control valve unit 4 includes the switching valve 31, the check valve 32, and the superheat degree control valve 33. In this embodiment, the switching valve 31 and the check valve 32 are integrally provided as a composite valve 35. First, the configuration and operation of the composite valve 35 will be described. FIG. 3 is a cross-sectional view illustrating a specific configuration and operation of the composite valve. In the following description, for the sake of convenience, the positional relationship between the structures may be expressed based on the illustrated state.

  The composite valve 35 is configured by assembling a valve body 101 and a solenoid 102. The valve body 101 accommodates a main valve 105 (functioning as a “first valve”), a pilot valve 106 and a subvalve 107 (functioning as a “second valve”) coaxially in a bottomed cylindrical body 103. Configured. The body 103 has a double structure configured by assembling a second body 109 obtained by injection molding of a resin material inside the first body 108 obtained by cutting a metal material. An inlet port 110 and an inlet / outlet port 112 are provided on one side of the first body 108, and an outlet port 114 is provided on the other side. The inlet port 110 communicates with the upstream passage (first passage 21), the inlet / outlet port 112 communicates with the intermediate passage (second passage 22), and the outlet port 114 communicates with the downstream passage (bypass passage 29).

  The second body 109 forms an internal passage of the body 103 and accommodates a valve mechanism. A communication hole that communicates the inside and the outside is provided in a portion facing the inlet port 110 of the second body 109 and a portion facing the inlet / outlet port 112, respectively, and the sealing member 118 extends across the boundary portion with the first body 108. , 120 are fitted. A flange 115 is projected inward in the radial direction at the center in the axial direction of the second body 109, and a guide hole 116 is formed by the inner periphery thereof. A sealing O-ring 119 is fitted on the inner peripheral surface of the guide hole 116.

  The inside of the second body 109 is partitioned into an upper pressure chamber 120 and a lower pressure chamber 122 by a flange portion 115, and a pressure chamber 124 is formed below the second body 109. The pressure chamber 120 communicates with the inlet port 110, the pressure chamber 122 communicates with the inlet / outlet port 112, and the pressure chamber 124 communicates with the outlet port 114. And inside the 2nd body 109, the valve drive body 126, the composite valve body 128, and the movable valve body 130 are accommodated so that these pressure chambers may be divided.

  A communication groove 134 extending along the longitudinal direction is formed on the outer peripheral portion of the second body 109, and a communication path 136 is formed between the second body 109 and the body 103. On the other hand, a stepped disk-shaped partition member 138 is provided so as to seal the upper end opening of the first body 108. The partition member 138 has an outer diameter that gradually decreases in the downward direction, and a lower half portion of the partition member 138 is fitted in the upper end opening of the second body 109. An O-ring for sealing is interposed on the joint surface between the partition member 138 and the second body 109. The partition member 138 is provided with a through hole along the axis, and a pilot valve hole 140 is formed by the lower half of the through hole. Further, a communication passage 142 extends radially outward from the through hole, and communicates the inside and outside of the partition member 138. The communication passage 142 and the communication passage 136 form a pilot passage 144. The pilot passage 144 allows the pilot valve hole 140 and the pressure chamber 124 to communicate with each other.

  The valve driver 126 has a stepped cylindrical shape, and a lower half portion thereof is slidably supported by the guide hole 116. A flange portion 146 extending outward in the radial direction is provided at the upper end opening of the valve driver 126, and is slidably supported on the upper inner peripheral surface of the second body 109. An O-ring for sealing is fitted on the outer peripheral surface of the flange portion 146. Further, a bottomed cylindrical partition member 148 is fitted so as to seal the upper end opening of the valve driver 126. An O-ring for sealing is interposed on the joint surface between the partition member 148 and the second body 109. A movable partition portion is formed by the partition member 148 and the flange portion 146, and the pressure chamber 120 is partitioned into a high pressure chamber 150 and a back pressure chamber 152 by the partition portion. That is, the back pressure chamber 152 is formed by a space sandwiched between the partition portion of the valve driver 126 and the partition member 138. The partition member 138 also functions as a locking portion that locks the valve driver 126 from above and defines the top dead center. The valve driver 126 has a reduced diameter portion at the center in the longitudinal direction, a main valve hole 154 is formed by an inner peripheral portion thereof, and a main valve seat 156 is formed at an upstream opening end portion thereof.

  The composite valve body 128 is configured such that a main valve body 160 is integrally formed at an upper end portion of a long operating rod and a sub-valve body 162 is screwed to a lower end portion. The composite valve body 128 is coaxially disposed so as to penetrate the main valve hole 154 of the valve driver 126. A ring-shaped elastic body is fitted to the main valve body 160, and the elastic body attaches / detaches to / from the main valve seat 156 from the upstream side to open and close the main valve 105. Similarly, a ring-shaped elastic body is also fitted to the auxiliary valve body 162. Since the main valve body 160 and the sub-valve body 162 are integrated via the operating rod, the other is linked to one of the operations.

  A spring 164 that biases the main valve body 160 in the valve closing direction is interposed between the main valve body 160 and the partition member 148. On the lower surface of the partition member 148, there is formed a communication groove for communicating the inside and outside even when the main valve body 160 abuts as shown in the figure. Also, a leak passage 166 having a small cross section is formed at the center of the partition member 148, and a circular boss-shaped valve seat forming portion 168 is provided so as to surround the leak passage 166 on the back pressure chamber 152 side. The valve seat forming portion 168 is attached to and detached from the pilot valve body 170 of the pilot valve 106 at the upper end surface thereof, and a very small communication groove 172 is provided at a predetermined position of the upper end surface. That is, the communication groove 172 forms a minute passage that allows passage of a small amount of refrigerant even when the valve seat forming portion 168 contacts the pilot valve body 170. The flow passage cross section of this minute passage is further smaller than the flow passage cross section of the leak passage 166, details of which will be described later.

  Between the partition member 148 and the partition member 138, a spring 174 for biasing the main valve body 160 in the valve closing direction via the partition member 148 is interposed. A pilot valve seat 176 is formed by the opening edge of the pilot valve hole 140 in the partition member 138. The pilot valve body 170 is a ball-shaped valve body disposed in the back pressure chamber 152, and is attached to and detached from the pilot valve seat 176 to open and close the pilot valve 106. A spring 180 that biases the pilot valve body 170 in the valve closing direction is interposed between the pilot valve body 170 and the partition member 148. The pilot valve body 170 receives force in the valve opening direction by the solenoid 102, and details thereof will be described later.

  The movable valve body 130 has a ring-shaped main body and is slidably supported on the lower end portion of the second body 109. A ring-shaped seal member 182 made of an elastic body is fitted on the outer peripheral surface of the movable valve body 130. A valve seat 184 is provided at the upstream opening end of the movable valve body 130. The movable valve body 130 functions as a valve seat for the auxiliary valve 107 and also functions as a valve body for the check valve 32. That is, as shown in the figure, the auxiliary valve body 162 opens and closes the auxiliary valve 107 by being attached to and detached from the valve seat 184 from the pressure chamber 122 side. Further, the check valve 32 is opened and closed by the movable valve body 130 being attached to and detached from the sub-valve body 162 from the pressure chamber 124 side. A spring 186 that biases the movable valve body 130 in the valve closing direction is interposed between the bottom of the body 103 and the movable valve body 130.

  In such a configuration, the upstream pressure P1 introduced from the inlet port 110 when the main valve 105 is open passes through the leak passage 166 and becomes the intermediate pressure Pp in the back pressure chamber 152. Further, the upstream pressure P1 becomes an intermediate pressure P2 through the main valve 105, and is led out to the outdoor heat exchanger 5 side through the inlet / outlet port 112. Further, the intermediate pressure P2 introduced from the inlet / outlet port 112 when the auxiliary valve 107 is in the open state passes through the auxiliary valve 107 to become the downstream pressure P3 and is led out from the outlet port 114 to the bypass passage 29.

  On the other hand, the solenoid 102 is attached so as to seal the upper end portion of the body 103. A seal ring is interposed between the solenoid 102 and the body 103. The solenoid 102 includes a cylindrical sleeve 188, a cylindrical core 190 fixed to the lower portion of the sleeve 188, and a cylindrical plunger 192 disposed in the sleeve 188 so as to face the core 190 in the axial direction. A bobbin 193 is provided on the outer periphery of the sleeve 188, and an electromagnetic coil 194 is wound around the bobbin 193. A case 196 is provided so as to cover the electromagnetic coil 194 from the outside. The sleeve 188 passes through the case 196 in the axial direction. A current-carrying harness is drawn out from the electromagnetic coil 194.

  The core 190 is fixed so that the lower portion thereof is press-fitted into the through hole of the case 196. Further, a long operating rod 195 is fixed so as to pass through the core 190 along its axis and to be press-fitted into the center of the plunger 192. The lower end portion of the operating rod 195 can be operatively connected to the pilot valve body 170, and transmits a force in the valve opening direction to the pilot valve body 170 when the solenoid 102 is turned on.

  A spring 197 (corresponding to an “urging member”) is interposed between the plunger 192 and the core 190. A spring 198 (corresponding to a “biasing member”) is interposed between the plunger 192 and the sleeve 188. The spring 197 biases the pilot valve body 170 in the valve opening direction via the plunger 192. The spring 198 is a spring for adjusting the load of the spring 197.

  The composite valve 35 configured as described above functions as a pilot-actuated control valve that switches the open / close state of the main valve and the subvalve depending on whether the solenoid 102 is energized. Hereinafter, the operation will be described in detail. 4 to 9 and FIG. 3 that has already been described are explanatory views showing the operation of the composite valve 35. FIG. 3 shows a steady state in which the solenoid 102 is turned off (non-energized state), and corresponds to FIG. FIG. 6 shows a steady state in which the solenoid 102 is turned on (energized state), and corresponds to FIGS. 2B and 2C. 4 and 5 sequentially show the intermediate process when the solenoid 102 is switched from OFF to ON, and FIGS. 7 and 8 sequentially show the intermediate process when the solenoid 102 is switched from ON to OFF. FIG. 9 shows a reverse pressure state in which the downstream pressure P3 is higher than the intermediate pressure P2 when the solenoid 102 is turned on, and corresponds to FIG.

  That is, since the solenoid 102 is turned off during the cooling operation, the operating rod 195 is separated from the pilot valve body 170 by the urging force of the spring 197 as shown in FIG. Therefore, the pilot valve body 170 is seated on the pilot valve seat 176 by the biasing force of the spring 180, and the pilot valve 106 is closed. As a result, the intermediate pressure Pp in the back pressure chamber 152 becomes the upstream pressure P1, and the differential pressure (Pp−P2) increases, so that the valve driver 126 is driven downward. As a result, the main valve seat 156 is separated from the main valve body 160, and the main valve 105 maintains the valve open state. On the other hand, since the composite valve body 128 is pushed down by the drive of the valve drive body 126, the sub-valve body 162 is seated on the valve seat 184, and the sub-valve 107 maintains the closed state. For this reason, the refrigerant introduced from the inlet port 110 passes through the main valve 105 and is led out from the inlet / outlet port 112 toward the outdoor heat exchanger 5.

  Since the solenoid 102 is turned on during the heating operation and the specific heating operation, a suction force acts between the core 190 and the plunger 192, and the operating rod 195 is driven in the valve opening direction of the pilot valve 106. That is, when the solenoid 102 is turned on, the pilot valve body 170 is urged in the valve opening direction by the operating rod 195, so that the pilot valve 106 is opened as shown in FIG. As a result, the refrigerant in the back pressure chamber 152 is led out through the pilot valve hole 140 and the pilot passage 144.

  For this reason, as shown in FIG. 5, the differential pressure (P1-Pp) increases and the valve driver 126 is driven upward. As a result, the main valve body 160 is seated on the main valve seat 156 and the main valve 105 is closed, while the sub valve body 162 is separated from the valve seat 184 and the sub valve 107 is opened. Therefore, the passage of the refrigerant introduced from the inlet port 110 is blocked, and the refrigerant introduced from the inlet / outlet port 112 passes through the sub valve 107 and is led out from the outlet port 114 to the bypass passage 29. At this time, since the pilot valve body 170 is seated on the valve seat forming portion 168, the refrigerant squeezed by the leak passage 166 is introduced into the back pressure chamber 152 so as to be further squeezed by the leak passage by the communication groove 172. It is led out through the valve hole 140. And as shown in FIG. 6, the pilot valve 106 will be in the state which maintains a very small opening degree.

  In this way, until the solenoid 102 is turned on and becomes in a steady state, the valve driver 126 rises, and the opening of the pilot valve 106 is throttled while the leak passage to the back pressure chamber 152 is further throttled. To work. That is, when the solenoid 102 is turned on, the refrigerant introduced into the back pressure chamber 152 from the inlet port 110 is merely led out from the pilot valve hole 140 as it is, and becomes a wasteful flow rate. By restricting the leak passage to the pressure chamber 152, waste can be suppressed.

  On the other hand, when the solenoid 102 is turned off from on, the suction force does not act between the core 190 and the plunger 192, so that the operating rod 195 is separated from the pilot valve body 170 as shown in FIG. Therefore, the pilot valve body 170 is seated on the pilot valve seat 176 by the biasing force of the spring 180, and the pilot valve 106 is closed. As a result, the intermediate pressure Pp in the back pressure chamber 152 becomes the upstream pressure P1, and the differential pressure (Pp−P2) increases, so that the valve driver 126 is driven downward as shown in FIG. At this time, since the upstream pressure P1 is higher than the intermediate pressure P2 and the intermediate pressure P2 is higher than the downstream pressure P3, the composite valve body 128 operates in the valve closing direction together with the driving of the valve driver 126, The main valve 105 remains closed, and the sub valve 107 operates in the valve closing direction. Then, as shown in FIG. 8, when the sub-valve 107 is closed, the composite valve body 128 remains locked and cannot move even if the valve driver 126 is driven downward. For this reason, the main valve 105 is opened as shown in FIG.

  As described above, the valve driver 126 is driven by the increase of the intermediate pressure Pp in the back pressure chamber 152 until the solenoid 102 is turned off to be in a steady state, but as described above, the communication groove 172 is driven. As a result, the intermediate pressure Pp can be quickly raised and the valve driver 126 can be driven quickly.

  Since the solenoid 102 is turned on during the special cooling / heating operation, the main valve 105 maintains the closed state. On the other hand, as shown in FIG. 2D, the second refrigerant circulation passage is blocked and the outdoor heat exchanger 5 is placed at a cryogenic temperature, so that the pressure in the outdoor heat exchanger 5 is also considerably reduced. That is, the downstream pressure P3 becomes higher than the intermediate pressure P2. For this reason, as shown in FIG. 9, a reverse pressure is applied to the movable valve body 130, and the check valve 32 is closed. As a result, the reverse flow of the refrigerant is prevented.

Next, the configuration and operation of the superheat degree control valve 33 will be described. FIG. 10 is a cross-sectional view illustrating a specific configuration and operation of the superheat degree control valve 33.
The superheat degree control valve 33 is configured by housing a main valve 205 and a pilot valve 206 coaxially in a body 203. An inlet port 210 is provided on one side of the body 203 and an outlet port 212 is provided on the other side. A cylindrical inner body 204 is coaxially provided inside the body 203.

  A bottomed cylindrical partition member 220 is press-fitted into the upper end portion of the inner body 204, and a power element 222 is provided so as to seal the upper end opening. In addition, a communication hole 213 that communicates the inside and the outside is provided at a position facing the inlet port 210 at the lower end of the inner body 204, and a main valve hole 214 is provided at the lower end opening. A communication passage 221 that communicates the inside and the outside is provided in a side portion of the partition member 220, and a pilot valve hole 223 that communicates the inside and the outside is provided in the center of the bottom portion.

  The power element 222 senses the temperature and pressure of the refrigerant introduced from the inlet port 210 and drives the pilot valve 206 and thus the main valve 205 to open and close. The power element 222 includes a hollow housing 224 and a diaphragm 226 arranged so as to partition the inside of the housing 224 into a sealed space S1 and an open space S2. The sealed space S1 constitutes a temperature-sensitive room, and a mixed gas of refrigerant gas (HFC-134a) and nitrogen gas circulating in the refrigeration cycle is enclosed as a reference gas. In the modified example, the same type of gas as the refrigerant gas circulating in the refrigeration cycle may be used as the reference gas.

  A pilot valve body 228 is disposed so as to contact the lower surface of the diaphragm 226. The pilot valve body 228 is attached to and detached from the pilot valve hole 223 to open and close the pilot valve 206. A spring 230 that biases the pilot valve body 228 in the valve opening direction is interposed between the pilot valve body 228 and the partition member 220.

  A stepped cylindrical valve driver 232 is disposed in the lower half of the inner body 204. The upper end of the valve driver 232 is slidably supported by the inner body 204. The valve driver 232 penetrates the main valve hole 214 and extends downward, and a main valve body 215 is provided at the lower end thereof. The main valve body 215 contacts and separates from the main valve hole 214 from the downstream side to open and close the main valve 205. A spring 217 that biases the main valve body 215 in the valve closing direction is interposed between the main valve body 215 and the body 203.

  A back pressure chamber 234 is formed between the upper end of the valve driver 232 and the partition member 220. Further, a pilot passage 236 is provided so as to penetrate the valve driver 232 in the axial direction, and the upper end portion thereof is reduced in diameter to form a leak passage 238 having a small cross section. On the other hand, a small valve body 240 capable of opening and closing the lower end opening of the pilot passage 236 is disposed. A spring 242 that biases the small valve body 240 in the valve closing direction is interposed between the small valve body 240 and the valve drive body 232. The small valve body 240 functions as a check valve that closes the pilot passage 236 when back pressure is applied to the superheat control valve 33.

  In such a configuration, the refrigerant having the upstream pressure Pin introduced through the inlet port 210 is decompressed and expanded on the one hand through the main valve 205 to become the downstream pressure Pout, and on the other hand through the pilot valve 206 to the back pressure chamber. At 234, the pressure becomes an intermediate pressure Pp2 and then reaches the downstream pressure Pout through the leak passage 238. The intermediate pressure Pp2 varies depending on whether the pilot valve 206 is open or closed.

  Here, the power element 222 senses the temperature and pressure of the refrigerant introduced from the inlet port 210, operates so that the superheat degree of the refrigerant approaches a set superheat degree SH (for example, 5 deg), and opens the pilot valve 206. Adjust the degree. That is, the power element 222 operates so that the superheat degree on the inlet side of the superheat degree control valve 33 (that is, the outlet side of the outdoor heat exchanger 5) becomes the set superheat degree SH during the heating operation. The opening degree of the main valve 205 is adjusted.

  That is, in the superheat degree control state, when the upstream superheat degree becomes larger than the set superheat degree SH, the power element 222 senses a high temperature and operates in the valve closing direction of the pilot valve 206. As a result, the valve opening of the pilot valve 206 is reduced, so that the intermediate pressure Pp2 is reduced and the valve driver 232 operates in the valve closing direction. As a result, since the upstream pressure Pin increases, the amount of heat exchange on the upstream side decreases, and the degree of superheat decreases. Conversely, when the degree of superheat is smaller than the set degree of superheat SH, the power element 222 senses the low temperature and operates in the valve opening direction of the pilot valve 206. As a result, the valve opening of the pilot valve 206 increases, so that the intermediate pressure Pp2 increases and the valve driver 232 operates in the valve opening direction. As a result, the upstream pressure Pin decreases, so the amount of heat exchange on the upstream side increases and the degree of superheat increases. In this way, the superheat degree is maintained at the set superheat degree SH.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the specific embodiments, and various modifications can be made within the scope of the technical idea of the present invention. Nor.

  In the above-described embodiment, an example in which the vehicle air conditioning apparatus according to the present invention is applied to an electric vehicle has been described. However, the present invention can be provided to an automobile equipped with an internal combustion engine or a hybrid automobile equipped with an internal combustion engine and an electric motor. Needless to say. In the above-described embodiment, an example in which an electric compressor is employed as the compressor 2 has been described. However, a variable capacity compressor that performs variable capacity using the rotation of the engine may be employed.

  In the said embodiment, the switching valve 31 was arrange | positioned in the branch point with the bypass passage 29 of the 2nd channel | path 22, and the example which comprised the switching valve 31 with a three-way solenoid valve was shown. In a modification, a switching valve may be provided on the compressor 2 side of the second passage 22 with respect to the bypass passage 29, and the switching valve may be constituted by a two-way electromagnetic valve. The switching valve may be a pilot operated control valve as with the switching valve 31. Specifically, in the switching valve 31 shown in FIG. 3, the auxiliary valve 107 may be eliminated and the inlet / outlet port 112 may be configured as an outlet port. The pilot passage 144 may be connected to the outlet port. Even in such a configuration, since the opening of the introduction passage for introducing the fluid into the back pressure chamber is restricted and the opening of the outlet passage for extracting the fluid from the back pressure chamber is provided, the same mechanism as in the above embodiment is provided. It becomes possible to obtain an effect.

  DESCRIPTION OF SYMBOLS 1 Vehicle air conditioner, 2 Compressor, 3 Indoor condenser, 4 First control valve unit, 5 Outdoor heat exchanger, 6 Second control valve unit, 7 Evaporator, 8 Accumulator, 31 Switching valve, 32 Check valve 33 Superheat control valve, 35 Composite valve, 41 Supercooling control valve, 42 Proportional valve, 43 Supercooling control valve, 44 Check valve, 100 Control unit, 101 Valve body, 102 Solenoid, 103 Body, 105 Main Valve, 106 Pilot valve, 107 Sub valve, 110 Inlet port, 112 Outlet / inlet port, 114 Outlet port, 126 Valve driver, 128 Compound valve body, 130 Movable valve body, 140 Pilot valve hole, 144 Pilot passage, 148 Partition member, 150 high pressure chamber, 152 back pressure chamber, 154 main valve hole, 156 main valve seat 160 Main valve body, 162 Sub valve body, 166 Leak passage, 170 Pilot valve body, 172 Communication groove, 176 Pilot valve seat, 184 Valve seat, 190 Core, 192 Plunger, 195 Actuating rod, 203 body, 204 Internal body, 205 main valve, 206 pilot valve, 210 inlet port, 212 outlet port, 214 main valve hole, 215 main valve body, 222 power element, 223 pilot valve hole, 228 pilot valve body, 232 valve driver, 234 back pressure chamber, 236 pilot passage, 238 leak passage, 240 small valve body, S1 sealed space, S2 open space.

Claims (6)

A pilot operated control valve that controls opening and closing of the main valve by changing the pressure of the back pressure chamber by opening and closing of the pilot valve,
A control valve comprising: a mechanism for restricting an opening degree of an introduction passage for introducing fluid into the back pressure chamber, and for reducing an opening degree of an outlet passage for extracting fluid from the back pressure chamber. A control valve provided between the upstream passage, the intermediate passage, and the downstream passage, and capable of switching the flow of fluid between the passages;
A first internal passage that has an inlet port connected to the upstream passage, an intermediate port connected to the intermediate passage, and an outlet port connected to the downstream passage, and directly connects the inlet port and the intermediate port; A body formed with a second internal passage that directly connects the intermediate port and the outlet port, and a sub-passage that connects the inlet port and the outlet port via the back pressure chamber;
A main valve having a main valve body that opens and closes the first internal passage by contacting and separating from a main valve hole provided in the first internal passage;
A sub-valve having a sub-valve element that opens and closes the second internal passage by contacting and separating from a sub-valve hole provided in the second internal passage;
The main valve includes a partition portion that is supported by the body so as to be relatively displaceable while forming the back pressure chamber with the body, and that has a leak passage that is one of the introduction passage and the discharge passage. A valve driver that opens and closes the main valve in conjunction with the body;
A pilot valve having a pilot valve body that opens and closes the sub-passage by making contact with and separating from a pilot valve hole which is the other of the introduction passage and the lead-out passage;
An actuator for driving the pilot valve;
With
When the valve driver operates in a direction to reduce the back pressure chamber, the pilot valve body closes the pilot valve hole to reduce the opening of the pilot valve hole and close to the leak passage. The control valve according to claim 1, wherein an opening degree of the leak passage is reduced. The main valve hole is formed in the valve driver,
When the main valve is in a closed state, the main valve body and the valve drive body can operate integrally, and when the main valve is in a valve open state, the main valve body and the valve drive body can operate independently. The control valve according to claim 2, wherein A composite valve body in which the main valve body and the sub-valve body are provided integrally;
The main valve can be opened when the sub valve is closed, the sub valve can be opened when the main valve is closed, and the main valve and the sub valve are opened. 4. The control valve according to claim 2, wherein both of them pass through a state in which they are closed when switching.   The sub-valve is formed when the sub-valve is formed and supported by the body so as to be displaceable from the sub-valve, and when the pressure in the downstream passage becomes higher than the pressure in the intermediate passage. The control valve according to any one of claims 2 to 4, further comprising a check valve that operates in a direction close to a body and forcibly closes the auxiliary valve. A control valve provided between an upstream passage and a downstream passage and capable of controlling a flow of refrigerant from the upstream passage to the downstream passage;
A main passage having an inlet port connected to the upstream passage and an outlet port connected to the downstream passage, and directly connecting the inlet port and the outlet port; and the back pressure between the inlet port and the outlet port. A body formed with a sub-passage connecting through the chamber;
A main valve having a main valve body that opens and closes the main passage by coming into contact with and separating from a main valve hole provided in the main passage;
A partition portion that is supported by the body so as to be relatively displaceable while forming the back pressure chamber between the body and a leak passage that is one of the introduction passage and the discharge passage;
A pilot valve having a pilot valve body that opens and closes the sub-passage by making contact with and separating from a pilot valve hole which is the other of the introduction passage and the lead-out passage;
An actuator for driving the pilot valve;
With
When the partition portion operates in a direction to reduce the back pressure chamber, the pilot valve body closes the pilot valve hole to reduce the opening of the pilot valve hole, and close to the leak passage The control valve according to claim 1, wherein the opening degree of the leak passage is reduced.

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