Expansion valve, vehicle heating / cooling device, and battery cooling device

Abstract

To provide an expansion valve capable of causing predetermined outlet side pressure that is pressure of a refrigerant on a downstream side to promptly come close to set pressure and of changing the set pressure as appropriate.SOLUTION: An expansion valve 1 in an aspect includes: a body 5 having a port 16 for introducing a refrigerant from an upstream side, a port 14 leading out the refrigerant to a downstream side, a valve hole 20 provided in a refrigerant passage connecting the port 16 and the port 14 and a pressure sensing chamber 23 to which outlet side pressure is introduced; a valve element 30 adjusting an opening of a valve part formed between the valve element and the valve hole 20; a pressure sensing section 6 provided in the pressure sensing chamber 23, sensing the outlet side pressure to generate driving force in an opening / closing direction of the valve part, displaced in a valve opening direction of the valve part when the outlet side pressure declines and displaced in the valve closing direction of the valve part when the outlet side pressure increases; and a solenoid 3 generating the driving force in the opening / closing direction of the valve part corresponding to a supply current value. By changing the supply current value to the solenoid 3, setting of set pressure can be changed.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to an expansion valve that reduces the pressure and expands a refrigerant. [Background technology]

[0002] Automotive air conditioners generally consist of a refrigeration cycle that includes a compressor, condenser, expansion device, evaporator, etc. The refrigeration cycle is equipped with various control valves, such as an expansion valve, to control the flow of refrigerant. The expansion valve throttles and expands the liquid refrigerant from the upstream side, turning it into atomized refrigerant and sending it downstream to facilitate evaporation of the refrigerant in the downstream evaporator.

[0003] Conventionally, a known type of expansion valve is a temperature-controlled expansion valve that senses the temperature and pressure of the refrigerant at the outlet side of the evaporator and adjusts the valve opening to control the flow rate of the refrigerant delivered to the evaporator so that the refrigerant delivered from the evaporator has a predetermined degree of superheat (see, for example, Patent Document 1). However, because the valve section of such an expansion valve operates autonomously solely through a mechanical structure, the relationship between the sensed pressure and the valve opening, in other words, the set value (also referred to as the "set pressure") of the evaporator outlet pressure adjusted by the expansion valve, is uniform. For this reason, there is room for improvement in that the set pressure cannot be changed when, for example, the control state required for the refrigeration cycle changes.

[0004] Meanwhile, with the recent spread of electric vehicles and the like, electrically operated expansion valves equipped with motors in their drive units are becoming widely adopted. Since electric vehicles do not have a heat source such as an internal combustion engine, they employ heat pump-type vehicle air conditioning systems that use a refrigerant for cycle operation for heating as well as cooling, and are capable of dehumidifying and heating the passenger compartment (see, for example, Patent Document 2). With an electrically operated expansion valve, the valve opening can be freely changed by external control, so the evaporator outlet pressure can also be set and changed as desired. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-242129 [Patent Document 2] Japanese Patent Application Laid-Open No. 2015-105715 Summary of the Invention [Problem to be solved by the invention]

[0006] However, because such an electric expansion valve does not have a pressure sensing element, it is not possible to sense the evaporator outlet pressure and provide feedback. This makes it difficult to improve responsiveness when adjusting to the set pressure. This same problem can also occur when expansion valves are used in air conditioning or cooling systems other than those for automobiles.

[0007] The present invention has been made in consideration of such problems, and its purpose is to provide an expansion valve that can quickly bring a predetermined outlet pressure, which is the pressure of the downstream refrigerant, close to a set pressure and that can change the set pressure as needed. [Means for solving the problem]

[0008] One aspect of the present invention is an expansion valve that reduces the pressure of refrigerant introduced from an upstream side, expands the refrigerant, and discharges it downstream, while controlling the refrigerant flow rate so that the outlet pressure, i.e., the pressure of the refrigerant at the downstream side, approaches a set pressure. The expansion valve includes a body having an inlet port for introducing refrigerant from the upstream side, an outlet port for discharging refrigerant to the downstream side, a valve hole provided in a refrigerant passage connecting the inlet port and the outlet port, and a pressure sensing chamber to which the outlet pressure is introduced; a valve element for adjusting the aperture of a valve portion formed between the valve hole and the body; a pressure sensing portion provided in the pressure sensing chamber that senses the outlet pressure and generates a driving force to open or close the valve portion, such that the valve portion is displaced in the opening direction when the outlet pressure decreases and in the closing direction when the outlet pressure increases; and a solenoid that generates the driving force in the opening or closing direction of the valve portion in response to a supplied current. The set pressure can be changed by changing the value of the current supplied to the solenoid.

[0009] According to this aspect, when the expansion valve is in a controlled state, the pressure-sensing unit senses the outlet pressure and drives the valve unit in the opening and closing direction. This allows the outlet pressure to quickly approach the set pressure. Furthermore, by changing the value of the current supplied to the solenoid, the set pressure can be changed as desired.

[0010] Another aspect of the present invention is a vehicle air-conditioning system including: a compressor that compresses and discharges a refrigerant; an exterior heat exchanger that is disposed outside the vehicle cabin and functions as an exterior condenser that radiates heat from the refrigerant during cooling operation and as an exterior evaporator that evaporates the refrigerant during heating operation; an interior evaporator that is disposed inside the vehicle cabin and evaporates the refrigerant; an auxiliary condenser that radiates heat from the refrigerant separately from the exterior heat exchanger; a first refrigerant circulation passage through which refrigerant discharged from the compressor can circulate during cooling operation, passing through the exterior heat exchanger and the interior evaporator in that order, and then returning to the compressor; a second refrigerant circulation passage through which refrigerant discharged from the compressor can circulate during heating operation, passing through the auxiliary condenser and the exterior heat exchanger in that order, and then returning to the compressor; a first valve that is disposed in the first refrigerant circulation passage downstream of the exterior heat exchanger, and that adjusts the flow rate of refrigerant supplied to the interior evaporator; and a second valve that is disposed in the second refrigerant circulation passage downstream of the auxiliary condenser, and that adjusts the flow rate of refrigerant supplied to the exterior heat exchanger. The first and second valves are expansion valves that reduce the pressure of the refrigerant introduced from the upstream side, expand it, and discharge it to the downstream side, while controlling the refrigerant flow rate so that the outlet pressure, which is the pressure of the refrigerant on the downstream side, approaches a set pressure.

[0011] This expansion valve includes a body having an inlet port for introducing refrigerant from the upstream side, an outlet port for discharging refrigerant to the downstream side, a valve hole provided in a refrigerant passage connecting the inlet port and the outlet port, and a pressure sensing chamber to which outlet pressure is introduced, a valve element for adjusting the opening of a valve portion formed between the valve hole and the body, a pressure sensing portion provided in the pressure sensing chamber for sensing outlet pressure and generating a driving force for opening or closing the valve portion, such that the valve portion is displaced in the opening direction when the outlet pressure decreases and in the closing direction when the outlet pressure increases, and a solenoid for generating the driving force for opening or closing the valve portion in accordance with the value of a supplied current. The set pressure can be changed by changing the value of the current supplied to the solenoid.

[0012] According to this aspect, when the heating and cooling system is in a controlled state, the pressure-sensing portion of the expansion valve senses the evaporator outlet pressure and drives the valve portion in the opening and closing directions. This allows the evaporator outlet pressure to quickly approach the set pressure, thereby maintaining heating and cooling capacity. In addition, the set pressure can be changed as desired by changing the value of the current supplied to the expansion valve solenoid.

[0013] Yet another aspect of the present invention is a battery cooling device that includes a compressor that compresses and discharges a refrigerant, an outdoor heat exchanger, a refrigerant circulation passage through which the refrigerant discharged from the compressor can circulate via the outdoor heat exchanger and return to the compressor, a battery heat exchanger provided in the refrigerant circulation passage between the outdoor heat exchanger and the compressor, and an expansion valve provided in the refrigerant circulation passage between the outdoor heat exchanger and the battery heat exchanger, that reduces the pressure of the refrigerant from the outdoor heat exchanger and expands it to supply it to the battery heat exchanger, and that controls the refrigerant flow rate so that an outlet pressure, which is the pressure of the refrigerant on the downstream side, approaches a set pressure.

[0014] This expansion valve includes a body having an inlet port for introducing refrigerant from the upstream side, an outlet port for discharging refrigerant to the downstream side, a valve hole provided in a refrigerant passage connecting the inlet port and the outlet port, and a pressure sensing chamber to which outlet pressure is introduced, a valve element for adjusting the opening of a valve portion formed between the valve hole and the body, a pressure sensing portion provided in the pressure sensing chamber for sensing outlet pressure and generating a driving force for opening or closing the valve portion, such that the valve portion is displaced in the opening direction when the outlet pressure decreases and in the closing direction when the outlet pressure increases, and a solenoid for generating the driving force for opening or closing the valve portion in accordance with the value of a supplied current. The set pressure can be changed by changing the value of the current supplied to the solenoid.

[0015] According to this aspect, when the battery cooling device is in operation, the pressure-sensing portion of the expansion valve senses the outlet pressure of the battery cooling device and drives the valve portion in the opening and closing directions. This allows the outlet pressure of the battery cooling device to quickly approach the set pressure and maintain the cooling temperature. Furthermore, by changing the value of the current supplied to the solenoid of the expansion valve, the set pressure can be changed as desired. [Effects of the Invention]

[0016] According to the present invention, it is possible to provide an expansion valve that can quickly bring a predetermined outlet pressure, which is the pressure of the downstream refrigerant, close to a set pressure and can change the set pressure as needed. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a system configuration diagram of a vehicle air conditioning and heating device according to an embodiment; [Figure 2] FIG. 2 is a diagram illustrating the operation of a heating and cooling device. [Figure 3] FIG. 2 is a diagram illustrating the operation of a heating and cooling device. [Figure 4] FIG. 2 is a cross-sectional view showing the configuration of an expansion valve. [Figure 5] FIG. 5 is a partially enlarged cross-sectional view corresponding to the upper half of FIG. 4. [Figure 6] FIG. 4 is a diagram illustrating the operation of an expansion valve. [Figure 7] FIG. 4 is a diagram illustrating the operation of an expansion valve. [Figure 8] FIG. 4 is a diagram illustrating the operation of an expansion valve. [Figure 9] 10 is a partially enlarged cross-sectional view corresponding to the upper half of an expansion valve according to a first modification. FIG. [Figure 10] FIG. 10 is an enlarged view of the X portion of FIG. 9. [Figure 11] 10 is a partially enlarged cross-sectional view corresponding to the upper half of an expansion valve according to a second modification. FIG. [Figure 12] FIG. 10 is a partially enlarged cross-sectional view corresponding to the upper half of an expansion valve according to a third modification. [Figure 13] FIG. 10 is a partially enlarged cross-sectional view corresponding to the upper half of an expansion valve according to a fourth modification. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. For convenience, the following description may refer to the positional relationship of each structure based on the illustrated state. In the following embodiments and their modifications, substantially identical components will be designated by the same reference numerals, and their description will be omitted where appropriate.

[0019] FIG. 1 is a system configuration diagram of a vehicle air conditioning system according to an embodiment. The air conditioning system 100 includes a refrigeration cycle (refrigerant circulation circuit) in which a compressor 102, an auxiliary condenser 104 (indoor condenser), an outdoor heat exchanger 106, a receiver 108, an evaporator 110, and an accumulator 112 are connected by piping. The air conditioning system 100 is applied to electric vehicles and is configured as a heat pump air conditioning system that uses the heat of a refrigerant such as HFC-134a (alternative chlorofluorocarbon) or HFO-1234yf to condition the air inside the vehicle cabin as the refrigerant circulates through the refrigeration cycle while changing state.

[0020] The compressor 102, the exterior heat exchanger 106, and the receiver 108 are provided outside the vehicle cabin (engine compartment). Meanwhile, a duct 114 is provided inside the vehicle cabin for air heat exchange, with the evaporator 110 disposed upstream of the duct 114 in the air flow direction and the auxiliary condenser 104 disposed downstream. The auxiliary condenser 104 is configured as an interior condenser.

[0021] The cooling and heating system 100 is operated by switching between multiple refrigerant circulation paths during cooling operation and heating operation. This refrigeration cycle is configured so that the auxiliary condenser 104 and the outdoor heat exchanger 106 can operate in series as condensers, and the evaporator 110 and the outdoor heat exchanger 106 can switch between operating as evaporators. A first refrigerant circulation path through which the refrigerant circulates during cooling operation and a second refrigerant circulation path through which the refrigerant circulates during heating operation are formed.

[0022] The first refrigerant circulation path is a path through which the refrigerant circulates in the order of the compressor 102 → auxiliary condenser 104 → outdoor heat exchanger 106 → receiver 108 → evaporator 110 → accumulator 112 → compressor 102. The second refrigerant circulation path is a path through which the refrigerant circulates in the order of the compressor 102 → auxiliary condenser 104 → outdoor heat exchanger 106 → receiver 108 → accumulator 112 → compressor 102. In other words, the second refrigerant circulation path is a path that bypasses the evaporator 110.

[0023] Specifically, the discharge chamber of the compressor 102 is connected to the inlet of the auxiliary condenser 104 via a first passage 121, and the outlet of the auxiliary condenser 104 is connected to the inlet of the outdoor heat exchanger 106 via a second passage 122. The outlet of the outdoor heat exchanger 106 is connected to the inlet of the evaporator 110 via the receiver 108 in a third passage 123, and the outlet of the evaporator 110 is connected to the inlet of the accumulator 112 via a fourth passage 124 (return passage).

[0024] A branch point is provided midway through third passage 123, and a bypass passage 125 is provided that leads to an inlet of accumulator 112 so as to bypass evaporator 110. First passage 121, second passage 122, third passage 123, and fourth passage 124 form a first refrigerant circulation passage. First passage 121, second passage 122, third passage 123, and bypass passage 125 form a second refrigerant circulation passage.

[0025] The second passage 122 is provided with a branch passage 127 branching off from its main passage 126. An on-off valve 130 is provided in the main passage 126, and an expansion valve 140 (functioning as a "second valve") is provided in the branch passage 127. The on-off valve 130 opens or closes the main passage 126. A switching valve 132 for switching the flow path of the refrigerant is provided at a branch point of the third passage 123 with the bypass passage 125. An expansion valve 142 (functioning as a "first valve") is provided in the third passage 123 between the switching valve 132 and the evaporator 110.

[0026] In this embodiment, the on-off valve 130 is a solenoid-driven electromagnetic valve, but it may also be a motor-driven electric valve. The expansion valve 140 is a solenoid-driven electromagnetic valve. The on-off valve 130 is a normally-open valve that fully opens the valve portion when the solenoid is not energized. During cooling operation, the on-off valve 130 is opened to ensure a refrigerant flow rate in the main passage 126, while the expansion valve 140 is kept closed. During heating operation, the on-off valve 130 is closed and the expansion valve 140 is opened to throttle and expand the refrigerant.

[0027] The switching valve 132 is composed of a first valve unit that opens and closes the third passage 123, a second valve unit that opens and closes the bypass passage 125, and a three-way valve that drives each valve unit. Opening and closing the first valve unit allows or blocks the flow of refrigerant from the outdoor heat exchanger 106 to the evaporator 110. Opening and closing the second valve unit allows or blocks the flow of refrigerant directly from the outdoor heat exchanger 106 to the accumulator 112. That is, opening the first valve unit and closing the second valve unit opens the first refrigerant circulation passage and blocks the second refrigerant circulation passage. Closing the first valve unit and opening the second valve unit blocks the first refrigerant circulation passage and opens the second refrigerant circulation passage. Note that although a solenoid-driven electromagnetic valve is used in this embodiment, a motor-driven electric valve may also be used.

[0028] The expansion valve 142 is provided in the first refrigerant circulation passage. During cooling operation, the expansion valve 142 throttles and expands the refrigerant delivered from the outdoor heat exchanger 106 (outdoor condenser) and supplies the refrigerant to the evaporator 110. The expansion valve 142 senses the pressure of the refrigerant flowing from the evaporator 110 to the compressor 102 and operates autonomously to adjust the flow rate of the refrigerant flowing from the outdoor heat exchanger 106 to the evaporator 110. Details of the expansion valve 142 will be described later.

[0029] In duct 114, an indoor fan (not shown), an evaporator 110, and an auxiliary condenser 104 are arranged from the upstream side in the air flow direction. An air mix door 116 is rotatably provided upstream of the auxiliary condenser 104, and adjusts the ratio between the amount of air passing through the auxiliary condenser 104 and the amount of air bypassing the auxiliary condenser 104. In addition, an outdoor fan (not shown) is arranged opposite the outdoor heat exchanger 106.

[0030] The compressor 102 is configured as an electric compressor that houses a motor and a compression mechanism in a housing, is driven by current supplied from a battery (not shown), and the refrigerant discharge capacity changes depending on the rotation speed of the motor. Note that, since the electric compressor itself is well known, a description thereof will be omitted.

[0031] The auxiliary condenser 104 is provided in the vehicle cabin and functions as an interior condenser that dissipates heat from the refrigerant separately from the exterior heat exchanger 106. That is, the high-temperature, high-pressure refrigerant discharged from the compressor 102 dissipates heat as it passes through the auxiliary condenser 104. The air that is distributed according to the opening degree of the air mix door 116 undergoes heat exchange as it passes through the auxiliary condenser 104.

[0032] The outdoor heat exchanger 106 functions as an outdoor condenser that dissipates heat from the refrigerant passing through it during cooling operation, and as an outdoor evaporator that evaporates the refrigerant passing through it during heating operation. The outdoor heat exchanger 106 exchanges heat between the outside air and the refrigerant.

[0033] The evaporator 110 is disposed in the vehicle cabin and functions as an interior evaporator that evaporates the refrigerant passing through the interior. The refrigerant, which has been made low temperature and low pressure by passing through the expansion valve 142, evaporates as it passes through the evaporator 110. Air introduced from the upstream side of the duct 114 is cooled by its latent heat of evaporation. The cooled and dehumidified air is then divided into two parts, one that passes through the auxiliary condenser 104 and one that bypasses the auxiliary condenser 104, depending on the opening of the air mix door 116. The air that passes through the auxiliary condenser 104 is heated during its passage. The air that has passed through the auxiliary condenser 104 and the air that has bypassed it are mixed downstream of the auxiliary condenser 104, adjusted to a target temperature, and supplied to the vehicle interior through an air outlet (not shown).

[0034] This embodiment also includes a battery cooling device 150 that utilizes the cooling function of the air conditioner 100. That is, the air conditioner 100 is a vehicle air conditioner and also a cooling device that cools a battery (not shown). As described above, this battery supplies power to drive the compressor 102 and also supplies power to each part of the electric vehicle.

[0035] A bypass passage 128 is provided connecting the third passage 123 and the fourth passage 124 so as to bypass the evaporator 110, and a battery heat exchanger 152 is provided in the bypass passage 128. A passage (third refrigerant circulation passage) through which the refrigerant circulates is provided as a refrigerant circulation path for cooling the battery, such as the compressor 102 → auxiliary condenser 104 → exterior heat exchanger 106 → receiver 108 → battery heat exchanger 152 → accumulator 112 → compressor 102. The battery heat exchanger 152 includes a refrigerant pipe constituting the bypass passage 128, and heat exchange occurs between the battery and the low-temperature refrigerant when the refrigerant passes through the refrigerant pipe. More specifically, a coolant (not shown) circulates to cool the battery, and heat exchange occurs between the coolant and the refrigerant. An expansion valve 144 is provided upstream of the battery heat exchanger 152 in the bypass passage 128.

[0036] The air conditioning system 100 configured as described above is controlled by a control unit 160. The control unit 160 calculates the control amount of each actuator 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 160 determines the control amount (open / close state) of each control valve and the drive amount of the compressor 102 based on predetermined external information detected by various sensors, such as the temperature inside and outside the vehicle and the temperature of air blown out of the evaporator, and supplies a control current to drive them. As a result, the compressor 102 introduces refrigerant at a suction pressure Ps through its suction chamber, compresses it, and discharges it as refrigerant at a discharge pressure Pd.

[0037] Figures 2 and 3 are diagrams showing the operation of the air conditioning device 100. Figure 2(A) shows cooling operation, Figure 2(B) shows battery cooling operation, and Figure 2(C) shows simultaneous operation of cooling and battery cooling. Figure 3(A) shows heating operation, Figure 3(B) shows dehumidifying heating operation, and Figure 3(C) shows simultaneous operation of dehumidifying heating and battery cooling. The thick lines and arrows in the figures indicate the flow of refrigerant, and an "x" indicates that the flow of refrigerant is blocked.

[0038] (Cooling operation) As shown in FIG. 2(A), during cooling operation, the on-off valve 130 is opened and the expansion valve 140 is closed. Meanwhile, the first valve portion of the switching valve 132 is opened and the second valve portion is closed. This opens the first refrigerant circulation passage and blocks the second refrigerant circulation passage. Therefore, high-temperature, high-pressure gas refrigerant discharged from the compressor 102 is condensed by passing through the auxiliary condenser 104 and the outdoor heat exchanger 106. At this time, the outdoor heat exchanger 106 functions as an outdoor condenser.

[0039] The refrigerant discharged from the exterior heat exchanger 106 is separated into gas and liquid in the receiver 108, and the liquid refrigerant is supplied downstream. This liquid refrigerant is throttled and expanded by the expansion valve 142, becoming a low-temperature, low-pressure atomized refrigerant that is introduced into the evaporator 110. The refrigerant evaporates as it passes through the evaporator 110, cooling the air inside the vehicle cabin. The refrigerant discharged from the evaporator 110 passes through an internal passage (a "pressure sensing chamber 23," described later) of the expansion valve 142, and is returned to the compressor 102 via the accumulator 112. Because the expansion valve 144 is closed, the battery heat exchanger 152 does not function.

[0040] As shown in Fig. 2(B), in battery cooling operation, expansion valve 142 is closed and expansion valve 144 is open. At this time, low-temperature, low-pressure refrigerant that has passed through expansion valve 144 passes through battery heat exchanger 152, thereby cooling the battery. As shown in Fig. 2(C), when both expansion valves 142 and 144 are open, the battery is cooled in air-conditioning operation.

[0041] (Heating operation) As shown in FIG. 3(A), during heating operation, the on-off valve 130 is closed and the expansion valve 140 is open. Meanwhile, the first valve portion of the switching valve 132 is closed and the second valve portion is open. This blocks the first refrigerant circulation passage and opens the second refrigerant circulation passage. Therefore, the refrigerant does not pass through the evaporator 110, and the evaporator 110 essentially ceases to function. Only the outdoor heat exchanger 106 functions as an evaporator (outdoor evaporator).

[0042] The refrigerant discharged from the compressor 102 is condensed by passing through the auxiliary condenser 104. The refrigerant is throttled and expanded by the expansion valve 140, and becomes a low-temperature, low-pressure atomized refrigerant, which is introduced into the outdoor heat exchanger 106. The refrigerant evaporates while passing through the outdoor heat exchanger 106, absorbing heat from the outside. The refrigerant discharged from the outdoor heat exchanger 106 passes through the bypass passage 125 and returns to the compressor 102 via the accumulator 112.

[0043] As shown in FIG. 3(B), in the dehumidifying and heating operation, the second valve portion of the switching valve 132 is closed and the first valve portion is opened while the expansion valve 140 is kept open. This causes the refrigerant to pass through the outdoor heat exchanger 106 (outdoor evaporator) and the evaporator 110 (indoor evaporator). That is, the evaporation ratio of the circulating refrigerant in the outdoor heat exchanger 106 and the evaporator 110 is adjusted. At this time, the dehumidifying function of the evaporator 110 is activated. Even during this dehumidifying and heating operation, the battery heat exchanger 152 can be operated by opening the expansion valve 144 as shown in FIG. 3(C), thereby cooling the battery.

[0044] Next, the configuration of the expansion valve will be described in detail. The expansion valves 140, 142, and 144 applied to the air conditioner 100 are all solenoid-driven electromagnetic valves, and have the same configuration in this embodiment. For this reason, these will be referred to as "expansion valve 1" below and their details will be described.

[0045] FIG. 4 is a cross-sectional view showing the configuration of the expansion valve 1. The expansion valve 1 reduces the pressure of the refrigerant introduced from the upstream side and expands (throttles expansion) it before discharging it downstream, and controls the refrigerant flow rate so that the outlet pressure, which is the pressure of the refrigerant on the downstream side, specifically the outlet pressure Pe of the downstream heat exchanger, approaches a set pressure Pset. Here, the "downstream heat exchanger" corresponds to the outdoor heat exchanger 106 for the expansion valve 140, the evaporator 110 for the expansion valve 142, and the battery heat exchanger 152 for the expansion valve 144.

[0046] The expansion valve 1 is constructed by assembling a valve body 2 and a solenoid 3 in the axial direction. The valve body 2 has a stepped cylindrical body 5 (valve body), which houses a power element 6. The power element 6 functions as a "pressure-sensing part," sensing the outlet pressure Pe and generating a driving force (hereinafter also referred to as "pressure-sensing driving force") in the opening and closing direction of the valve part. The body 5 is assembled coaxially with the body 7 (solenoid body) of the solenoid 3.

[0047] On the other hand, port 12b is connected to the inlet of a downstream device located further downstream of the downstream heat exchanger. Here, the "downstream device" refers to the receiver 108 and the compressor 102 for the expansion valve 140, and to the accumulator 112 and the compressor 102 for the expansion valves 142 and 144.

[0048] An end member 13 is fixed to close the upper end opening of the body 5. The lower part of the body 5 and the upper part of the solenoid 3 are connected and fixed via a connecting member 51.

[0049] A valve hole 20 is provided in the body 5 in a refrigerant passage that connects the port 16 and the port 14, and a valve seat 22 is provided at the upstream open end of the valve hole 20. A valve element 30 (described below) is attached to and detached from the valve seat 22 to open and close the valve portion. The expansion valve 1 has a configuration in which a power element 6, a valve portion, and a solenoid 3 are arranged in this order from one end.

[0050] A pressure sensing chamber 23 is defined in the upper part of the body 5, and a power element 6 is provided in the pressure sensing chamber 23. Port 12a connects the outlet of the downstream heat exchanger with the pressure sensing chamber 23. Meanwhile, port 12b connects the inlet of the downstream device with the pressure sensing chamber 23. Port 16 introduces refrigerant at upstream pressure Pin from the upstream side. For expansion valve 140, the upstream pressure Pin is the pressure downstream of the auxiliary condenser 104 (indoor condenser). For expansion valves 142 and 144, the upstream pressure Pin is the pressure downstream of the outdoor heat exchanger 106 (outdoor condenser).

[0051] A valve chamber 24 is provided between the port 16 and the valve hole 20. The valve hole 20 has a tapered shape with a slightly enlarged diameter near the open end, and a valve seat 22 is formed on the tapered surface. The port 14 delivers the refrigerant that has passed through the valve section and reached a downstream pressure Pout toward the inlet of the downstream heat exchanger. The refrigerant that has passed through the downstream heat exchanger and reached an outlet pressure Pe is introduced into the pressure sensing chamber 23 via port 12a and then delivered to the downstream equipment via port 12b. The power element 6 senses the outlet pressure Pe of the pressure sensing chamber 23 and operates.

[0052] Cylindrical filter members 15 and 17 are attached to the ports 14 and 16, respectively. The filter members 15 and 17 include a mesh for preventing foreign matter from entering the body 5.

[0053] A downstream pressure chamber 25 is formed between the port 14 and the valve hole 20. The valve chamber 24, the valve hole 20, and the downstream pressure chamber 25 form a refrigerant passage connecting the port 16 and the port 14. A guide hole 26 is provided between the pressure sensing chamber 23 and the valve chamber 24, and a guide hole 27 is provided in the lower part of the body 5 (on the opposite side of the valve chamber 24 from the valve hole 20). The guide holes 26 and 27 are formed coaxially. A valve driver 29 is inserted along the axis of the body 5. The valve driver 29 is supported by the upper and lower guide holes 26 and 27 so as to be slidable in the axial direction. The valve driver 29 penetrates a partition wall 37 between the downstream pressure chamber 25 and the pressure sensing chamber 23, and is operatively connected to the power element 6.

[0054] The valve driver 29 is a stepped cylinder with a bottom, and has an internal passage 35 extending in the axial direction. The upper end of the valve driver 29 is reduced in diameter when closed, allowing it to be operatively connected to the power element 6. The lower end of the valve driver 29 is open toward the solenoid 3. A communication hole 28 that connects the pressure sensing chamber 23 and the internal passage 35 is provided in the upper part of the valve driver 29.

[0055] A step formed in the middle of the valve driver 29 serves as the valve element 30. The valve element 30 opens and closes the valve section by attaching to and detaching from the valve seat 22 from the valve chamber 24 side. The valve element 30 also adjusts the opening of the valve section by moving toward and away from the valve hole 20, thereby adjusting the amount of refrigerant flowing from the upstream side to the downstream side. A plunger 62 of the solenoid 3 is integrally assembled to the lower end of the valve driver 29.

[0056] The power element 6 includes a bellows 45 that senses the outlet pressure Pe and is displaced, and generates a pressure-sensitive driving force due to the displacement of the bellows 45. This pressure-sensitive driving force is transmitted to the valve driver 29 and ultimately to the valve element 30.

[0057] On the other hand, the solenoid 3 is configured by accommodating a drive mechanism inside a body 7. The body 7 includes a stepped cylindrical case 50 with a reduced diameter at the top end, a stepped cylindrical connecting member 51 coaxially press-fitted into the top end of the case 50, a cylindrical bobbin 52 housed within the case 50, an electromagnetic coil 54 wound around the bobbin 52, a cylindrical sleeve 56 inserted into the bobbin 52, an end member 58 provided to substantially seal the bottom opening of the case 50, and a collar 59 embedded in the end member 58 below the bobbin 52. The sleeve 56 is made of a non-magnetic material. The case 50, connecting member 51, and collar 59 are made of a magnetic material and constitute the "yoke" of the solenoid 3.

[0058] A plunger 62 and a core 64 are disposed in an operating space 60 formed inside the body 7. The upper end of the sleeve 56 is inserted into and fixed coaxially with the connecting member 51. The core 64 is cylindrical with a closed bottom, with the outer diameter of the upper part slightly reduced, and is assembled so that its upper part is inserted into the lower part of the sleeve 56. The core 64 is fixed coaxially with the sleeve 56 and closes the operating space 60 from below.

[0059] The plunger 62 has a stepped cylindrical shape and faces the core 64 in the axial direction. The central portion of the lower end of the valve driver 29 protrudes like a circular boss and is press-fitted into the upper opening of the plunger 62, thereby coaxially fixing the valve driver 29 and the plunger 62. A spring 68 (functioning as a "biasing member") is housed inside the core 64. The spring 68 is interposed between the bottom of the core 64 and the bottom of the plunger 62 and biases the plunger 62 in the valve closing direction. Only the spring 68 is inserted into the core 64 as a member supporting the plunger 62. The outlet pressure Pe is introduced into the operating space 60 through the internal passage 35 of the valve driver 29.

[0060] The driving force of the solenoid 3 (also referred to as "solenoid force"), which is the attractive force between the core 64 and the plunger 62, is transmitted to the valve driver 29 and ultimately to the valve element 30. That is, in the controlled state of the expansion valve 1, a force adjusted by the solenoid force and the pressure-sensitive driving force acts on the valve element 30, appropriately controlling the opening degree of the valve portion.

[0061] A communication groove 66 parallel to the axis is provided on the side surface of the plunger 62, and a communication hole 67 connecting the inside and outside of the plunger 62 is provided on the top of the plunger 62. With this configuration, the outlet pressure Pe is also introduced into the gap between the plunger 62 and the sleeve 56.

[0062] A pair of connection terminals 72 connected to the electromagnetic coil 54 extend from the bobbin 52 and each penetrates an end member 58 and is pulled out to the outside. For ease of explanation, only one of the pair is shown in the drawing. The end member 58 is attached so as to cover the entire structure inside the solenoid 3 contained in the case 50 from below. The end member 58 is formed by molding (injection molding) a corrosion-resistant resin material. The tip of the connection terminal 72 is pulled out from the end member 58 and is connected to an external power source (not shown).

[0063] FIG. 5 is a partially enlarged cross-sectional view corresponding to the upper half of FIG. An annular groove 73 is formed around the sliding surface of the valve driver 29 against the guide hole 27, and an O-ring 74 (sealing member) is fitted into the groove. This prevents refrigerant from flowing through the gap between the two. The plunger 62 is integrally formed with the valve driver 29, so that the solenoid force can be transmitted directly to the valve element 30.

[0064] The power element 6 is configured such that the upper end opening of the bellows 45 is closed by a first stopper 82 and the lower end opening is closed by a second stopper 84. The bellows 45 functions as a "pressure-sensing member." The first stopper 82 is integrally molded with the end member 13. The second stopper 84 is formed by pressing a metal material into a cylindrical shape with a bottom, and has a flange portion 86 extending radially outward at its lower end opening. The upper end of the bellows-shaped body of the bellows 45 is airtightly welded to the lower surface of the end member 13, and the lower end opening of the body is airtightly welded to the upper surface of the flange portion 86. The interior of the bellows 45 forms a sealed reference pressure chamber S. A spring 88 is interposed inside the bellows 45 between the end member 13 and the flange portion 86 to bias the bellows 45 in the expansion direction. The reference pressure chamber S is maintained in a vacuum state. The load of the spring 68 is sufficiently greater than the load of the spring 88. The valve opening degree when the solenoid 3 is turned off is related to the loads of the springs 68 and 88 as well as the load in the valve closing direction that is generated when the bellows 45 receives the outlet pressure Pe (hereinafter also referred to as the "pressure-receiving load"). For this reason, the pressure-receiving area of ​​the bellows 45 should be set so that the load of the spring 68 and the pressure-receiving load of the bellows 45 always overcome the load of the spring 88 when the solenoid 3 is turned off. In this case, the magnitude relationship between the load of the spring 68 and the load of the spring 88 does not matter.

[0065] The end member 13 serves as the fixed end of the power element 6. The set load of the power element 6 (the set load of the spring 88) can be adjusted by adjusting the amount by which the end member 13 is pressed into the body 5. The center portion of the first stopper 82 extends downward toward the inside of the bellows 45, and the center portion of the second stopper 84 extends upward toward the inside of the bellows 45, which together form the axis of the bellows 45.

[0066] The bellows 45 expands or contracts in the axial direction (the direction in which each valve opens or closes) depending on the pressure difference between the outlet pressure Pe of the pressure sensing chamber 23 and the reference pressure of the reference pressure chamber S. As the pressure difference decreases and the bellows 45 expands, a pressure-sensitive driving force in the valve opening direction is applied to the valve driver 29. As the outlet pressure Pe decreases, the bellows 45 expands, and the pressure-sensitive driving force in the valve opening direction increases. On the other hand, as the outlet pressure Pe increases, the bellows 45 contracts and displaces in the valve closing direction. As a result, the valve driver 29 and therefore the valve element 30 operate in the valve closing direction. At this time, if the outlet pressure Pe increases and the valve element 30 seats on the valve seat 22, the valve driver 29 stops. At this time, if the bellows 45 continues to contract even after the valve driver 29 has stopped, the upper end of the valve driver 29 separates from the flange portion 86, and the operative connection between the valve driver 29 and the power element 6 is released. However, when the bellows 45 contracts by a predetermined amount, the second stopper 84 comes into contact with and locks against the first stopper 82, thereby restricting the contraction.

[0067] By adjusting the solenoid force, the balance with the pressure-sensitive driving force of the power element 6 can be adjusted, thereby adjusting the set value of the outlet pressure Pe (set pressure Pset). In other words, as long as the value of the current supplied to the solenoid 3 is constant, the expansion valve 1 autonomously adjusts the opening of the valve section so that the outlet pressure Pe becomes the set pressure Pset corresponding to that supply current. In other words, the set pressure Pset can be changed by changing the value of the current supplied to the solenoid 3. Furthermore, by increasing the value of the current supplied to the solenoid 3 and increasing the solenoid force, the valve driver 29 and therefore the valve element 30 can be forcibly operated in the valve opening direction, regardless of the operating state of the power element 6, and the valve section can be fully opened.

[0068] Furthermore, with the plunger 62 fixed to the valve driver 29, the solenoid force can be transmitted directly to the valve element 30, and a large force can be applied to urge the valve element 30 in the valve opening direction. This configuration functions as an unlocking mechanism that unlocks the valve element 30 when the operation of the valve element 30 is locked due to foreign matter getting caught in the sliding portion between the valve driver 29 and the guide hole 26.

[0069] In this embodiment, the effective pressure-receiving diameter A (seal portion diameter) of the valve portion of the valve element 30, the sliding portion diameter B of the guide hole 26 of the valve driver 29, and the sliding portion diameter C of the guide hole 27 of the valve driver 29 are all equal. Note that "equal" here includes not only the concept of completely equal, but also the concept of almost equal (substantially equal). The outlet pressure Pe is also introduced into the operating space 60 of the solenoid 3 via the internal passage 35 of the valve driver 29. This cancels the effects of the upstream pressure Pin, downstream pressure Pout, and outlet pressure Pe acting on the valve element 30 (pressure cancellation structure). As a result, in the controlled state of the expansion valve 1, the valve element 30 operates in the opening and closing directions of the valve portion based on the outlet pressure Pe that the power element 6 receives in the pressure sensing chamber 23.

[0070] The pressure before and after (top and bottom in the drawing) the combination of the valve driver 29 and plunger 62 can be made the same pressure (outlet pressure Pe), thereby realizing pressure cancellation. This allows the diameter of each valve element to be set independently of the effective pressure-receiving diameter D of the bellows 45, providing a high degree of design freedom. In this embodiment, the diameter D of the bellows 45 is set equal to the diameters A, B, and C, but it may be larger or smaller than the diameters A, B, and C.

[0071] In this embodiment, strictly speaking, the sliding portion diameter B of the guide hole 26 of the valve driver 29 is made slightly smaller than the effective pressure-receiving diameter A of the valve element 30, and the differential pressure (Pout-Pe) between the downstream pressure Pout and the outlet pressure Pe acts on the valve driver 29 in the valve opening direction. Note that by making the sliding portion diameter B slightly smaller than the effective pressure-receiving diameter A in this manner, when the valve driver 29 is assembled to the body 5, the upper portion of the valve driver 29 (the portion connecting to the power element 6) can be passed through the valve hole 20 from below the body 5. In other words, even if the valve driver 29 is constructed as an integrated part (single part) as in this embodiment, it can be assembled to the body 5.

[0072] In a modified example, the sliding portion diameter B of the guide hole 26 of the valve driving body 29 may be made completely equal to the effective pressure-receiving diameter A of the valve body 30. In that case, the valve driving body 29 may be configured by assembling a first member slidably supported in the guide hole 26 and a second member slidably supported in the guide hole 27 coaxially in the axial direction.

[0073] Next, the operation of the expansion valve 1 will be described. In this embodiment, a PWM (Pulse Width Modulation) method is used to control the energization of the solenoid 3. This PWM control is performed by supplying a pulse current of about 400 Hz set to a predetermined duty ratio, and is executed by the control unit 160. The control unit 160 has a PWM output unit that outputs a pulse signal of a specified duty ratio, but since a known configuration is used for this, detailed description will be omitted.

[0074] Figures 6 to 8 are diagrams showing the operation of the expansion valve 1. Figure 6 shows the controlled state of the valve opening, and Figure 7 shows the fully open state of the valve section. Figure 5, which has already been explained, shows the closed valve state. Figure 8(A) is an enlarged view of part X in Figure 5, Figure 8(B) is an enlarged view of part X in Figure 6, and Figure 8(C) is an enlarged view of part X in Figure 7. The following explanation will be based on Figure 4, with reference to Figures 5 to 8 as appropriate.

[0075] When the expansion valve 1 is to be closed, the solenoid 3 is de-energized (turned off). At this time, no attractive force acts between the core 64 and the plunger 62. Meanwhile, the spring 68 pushes the valve driver 29 upward. As a result, as shown in FIG. 5, the valve element 30 seats on the valve seat 22, and the valve is closed (see FIG. 8(A)).

[0076] On the other hand, when the expansion valve 1 is to function, current is applied to the solenoid 3. The value of the current supplied at this time is set to a value corresponding to the set pressure Pset of the outlet pressure Pe. As a result, as shown in FIG. 6, the opening of the valve unit is autonomously adjusted so that the outlet pressure Pe becomes the set pressure Pset set by the value of the current supplied (see FIG. 8(B)). The set pressure Pset can also be changed by changing the value of the current supplied.

[0077] When it is desired to flow the maximum amount of refrigerant through the expansion valve 1, a current of a predetermined magnitude (also referred to as a "full-open current") is supplied to the solenoid 3 to fully open the expansion valve 1. The value of the current supplied at this time is also referred to as the "full-open current value." As a result, the expansion valve 1 can be brought into a fully open state, as shown in FIG. 7 (see FIG. 8(C)).

[0078] As described above, in this embodiment, when the air conditioner 100 is in operation, each expansion valve 1 can quickly bring the downstream outlet pressure Pe close to the set pressure Pset, and the set pressure Pset can be changed as needed.

[0079] During cooling operation, in the expansion valve 142, the power element 6 senses the outlet pressure Pe of the evaporator 110 and drives the valve unit in the opening / closing direction, thereby quickly bringing the outlet pressure Pe closer to the set pressure Pset appropriate for cooling. During heating operation, in the expansion valve 140, the power element 6 senses the outlet pressure Pe of the exterior heat exchanger 106 and drives the valve unit in the opening / closing direction, thereby quickly bringing the outlet pressure Pe closer to the set pressure Pset appropriate for heating. Furthermore, during battery cooling operation, in the expansion valve 144, the power element 6 senses the outlet pressure Pe of the battery heat exchanger 152 and drives the valve unit in the opening / closing direction, thereby quickly bringing the outlet pressure Pe closer to the set pressure Pset appropriate for battery cooling.

[0080] According to this embodiment, the set pressure Pset can be changed arbitrarily by changing the value of the current supplied to the solenoid 3. Therefore, it is easy to set the optimum set pressure Pset for each operating state, such as cooling, heating, dehumidification, and battery cooling, and the setting can also be changed quickly.

[0081] Furthermore, even though the expansion valve 1 is an electrically driven solenoid valve, it has a feedback function for the outlet pressure Pe, making it easy to control the outlet temperature of the air conditioner when the downstream heat exchanger is an evaporator.

[0082] Although the preferred embodiment of the present invention has been described above, it goes without saying that the present invention is not limited to this specific embodiment, and various modifications are possible within the scope of the technical concept of the present invention.

[0083] [Variations] Fig. 9 is a partially enlarged cross-sectional view corresponding to the upper half of the expansion valve according to Modification 1. Fig. 10 is an enlarged view of part X in Fig. 9. Fig. 10(A) shows the valve closed state, Fig. 10(B) shows the controlled state, and Fig. 10(C) shows the fully open state.

[0084] As shown in Fig. 9, the expansion valve 201 of this modified example is configured as a so-called spool valve. A valve hole 220 in the form of a stepped circular hole is formed in a body 205. The valve element 30 is inserted into and removed from the valve hole 220 to open and close the valve portion.

[0085] However, even in the closed valve state, the valve element 30 does not seat in the valve hole 220, and a predetermined clearance CL is formed between the valve element 30 and the valve hole 220 (Fig. 10(A)). A tapered flow adjustment section 222 with a slightly enlarged diameter is provided at the open end of the valve hole 220, and when the expansion valve 201 is in a controlled state, the valve element 30 approaches the flow adjustment section 222, thereby changing the refrigerant flow rate (i.e., adjusting the flow rate) (Fig. 10(B)). The expansion valve 201 can also be fully opened by supplying a full-open current to the solenoid 3 (Fig. 10(C)).

[0086] In this modification as well, the power element 6 senses the outlet pressure Pe, thereby enabling the outlet pressure Pe to be quickly brought closer to the set pressure Pset, and the set pressure Pset can be appropriately changed by changing the value of the current supplied to the solenoid 3. Furthermore, by making the valve section a spool structure, even if the valve element 30 vibrates due to PWM control when the valve section is slightly open, it is possible to prevent or suppress the valve element 30 from striking the valve seat, thereby suppressing the generation of abnormal noise from the valve section.

[0087] FIG. 11 is a partially enlarged cross-sectional view of the upper half of the expansion valve according to the second modification. In the expansion valve 221 of this modified example, an annular groove 273 is provided on the inner circumferential surface of the guide hole 26, and an O-ring 74 (sealing member) is fitted into the groove. This configuration prevents refrigerant from leaking through the gap between the valve driving body 29 and the guide hole 26. Note that in this modified example, contrary to the present embodiment, an annular groove may be provided on the outer circumferential surface of the valve driving body 29, and a sealing member such as an O-ring may be fitted into the groove.

[0088] FIG. 12 is a partially enlarged cross-sectional view of the upper half of the expansion valve according to the third modification. The expansion valve 231 of this modified example is not provided with an internal passage for introducing the outlet pressure Pe to the solenoid 3. The inner diameter of the guide hole 26 formed in the body 235 is sufficiently smaller than the diameter of the valve hole 20. A reduced diameter portion 230 extending from the upper end of the valve driver 229 slidably passes through the guide hole 26 and is operatively connected to the power element 6.

[0089] The effective pressure-receiving diameter A of the valve element 30 is equal to the sliding portion diameter C of the guide hole 27 of the valve driving element 229, but the sliding portion diameter B of the guide hole 26 of the valve driving element 229 is smaller than these. The operating space 60 of the solenoid 3 (see FIG. 4) and the downstream pressure chamber 25 are in communication with each other via the internal passage 253 of the valve driving element 229 and the communication hole 28. Therefore, the downstream pressure Pout is introduced into the operating space 60.

[0090] With this configuration, the refrigerant pressure acting on the valve driving body 229 and therefore the valve element 30 is largely canceled out, but the differential pressure (Pout-Pe) between the downstream pressure Pout and the outlet pressure Pe acts in the valve closing direction across the reduced diameter section 230. However, because the diameter of the reduced diameter section 230 is small, this effect is small. According to this modification, by reducing the size of the guide hole 26, the cross-sectional area of ​​the gap between the valve driving body 229 and the guide hole 26 can be reduced. This makes it possible to prevent foreign matter from entering the guide hole 26.

[0091] FIG. 13 is a partially enlarged cross-sectional view of the upper half of the expansion valve according to the fourth modification. The expansion valve 241 of this modification is slightly different from the expansion valve 231 of modification 3 in the structure of the power element 246. The power element 246 has a vibration-proof structure using a vibration-proof spring 250.

[0092] The vibration-proof spring 250 has an annular base portion 252 and a plurality of spring portions 254 provided at equal intervals along the periphery of the base portion 252. The base portion 252 is fixed in a manner that it is interposed between the bottom surface of the bellows 45 and the upper surface of the flange portion 86. Each spring portion 254 extends obliquely upward so that the distance between the spring portion 254 and the bellows 45 increases the further it extends upward. A hemispherical bulge 256 protrudes outward from the tip of the spring portion 254, and the bulge 256 abuts against the inner wall of the pressure sensing chamber 23 with a certain biasing force.

[0093] With this configuration, when the bellows 45 expands or contracts, the spring portion 254 slides along the inner circumferential surface of the body 235. Therefore, even if vibration of the valve driver 229 due to PWM control is transmitted to the power element 246, the vibration can be damped. Furthermore, even if pulsation occurs in any of the upstream pressure Pin, downstream pressure Pout, and outlet pressure Pe, the vibration of the valve element 30 caused by this pulsation can be damped by the vibration-damping spring 250.

[0094] [Other variations] In the above embodiment, an example was shown in which port 12a of expansion valve 1 is connected to the outlet of the downstream heat exchanger, and port 12b is connected to the inlet of the downstream equipment. In a modified example, both port 12a and port 12b may be connected to the outlet of the downstream heat exchanger, and outlet pressure Pe may be introduced into pressure sensing chamber 23. The number of ports may be multiple or may be single. In other words, pressure sensing chamber 23 may remain a pressure chamber that introduces refrigerant pressure, and may not constitute an internal passage through which refrigerant passes, as in the above embodiment.

[0095] In the above embodiment, the outlet pressure Pe of the downstream heat exchanger is sensed as the outlet pressure, which is the pressure of the refrigerant downstream of the expansion valve. In a modified example, the downstream pressure Pout delivered from the delivery port (port 14) may be sensed as the "outlet pressure."

[0096] In the above embodiment, the plunger 62 is disposed on the same side of the core 64 as the valve driver 29, and the solenoid 3 generates a driving force in the valve opening direction according to the value of the supplied current. That is, the expansion valve 1 is configured as a normally closed valve, and closes when the supply of current to the solenoid 3 is turned off. In a modified example, the expansion valve may be configured as a normally open valve. Specifically, the plunger is disposed on the opposite side of the core from the valve driver, and the solenoid generates a driving force in the valve closing direction according to the value of the supplied current. This may realize a configuration in which the valve opens when the supply of current to the solenoid 3 is turned off. Even if the expansion valve is configured as such a normally open valve, the set pressure of the outlet pressure Pe can be appropriately changed by changing the value of the current supplied to the solenoid during valve opening control.

[0097] In the above embodiment, the bellows 45 is exemplified as the pressure-sensitive member, but a diaphragm may also be used.

[0098] Although not mentioned in the above embodiment, a pressure-sensing gas may be sealed in the reference pressure chamber S of the power element 6, and the pressure and temperature of the refrigerant downstream of the expansion valve (outlet pressure) may be sensed and displaced. This may allow control so that the refrigerant discharged from the evaporator reaches a predetermined degree of superheat. This can improve air conditioning performance (efficiency). An optimal degree of superheat can be obtained in various operating modes.

[0099] In the above embodiment, the biasing member is a spring, but other biasing members such as rubber may also be used.

[0100] In the above embodiment, a heat pump type air conditioner is exemplified, but the air conditioner may have a normal refrigeration cycle that utilizes an internal combustion engine. The air conditioner may be applied not only to electric vehicles but also to automobiles equipped with internal combustion engines and hybrid vehicles. Furthermore, the expansion valve may be applied not only to vehicles but also to air conditioners for residential facilities and other purposes.

[0101] The present invention is not limited to the above-described embodiments and modifications, and the components can be modified without departing from the spirit of the invention. Various inventions can be formed by appropriately combining multiple components disclosed in the above-described embodiments and modifications. Furthermore, some components can be omitted from all the components shown in the above-described embodiments and modifications. [Explanation of symbols]

[0102] 1 expansion valve, 2 valve body, 3 solenoid, 5 body, 6 power element, 7 body, 12a port, 12b port, 14 port, 16 port, 20 valve hole, 22 valve seat, 23 pressure sensing chamber, 24 valve chamber, 25 downstream pressure chamber, 26 guide hole, 27 guide hole, 29 valve drive body, 30 valve body, 35 internal passage, 45 bellows, 50 case, 54 electromagnetic coil, 56 sleeve, 60 working space, 62 plunger, 64 core, 68 spring, 73 annular groove, 74 O-ring, 88 spring, 100 heating and cooling device, 102 compressor, 104 auxiliary condenser, 106 outdoor heat exchanger, 108 receiver, 110 evaporator, 112 accumulator, 121 first passage, 122 second passage, 123 Third passage, 124 Fourth passage, 125 Bypass passage, 126 Main passage, 127 Branch passage, 128 Bypass passage, 130 On-off valve, 132 Switching valve, 140 Expansion valve, 142 Expansion valve, 144 Expansion valve, 150 Battery cooling device, 152 Battery heat exchanger, 160 Control unit, 201 Expansion valve, 205 Body, 220 Valve hole, 221 Expansion valve, 222 Flow adjustment unit, 229 Valve drive body, 230 Diameter reduction unit, 231 Expansion valve, 235 Body, 241 Expansion valve, 246 Power element, 250 Vibration isolation spring, 252 Base unit, 254 Spring unit, 256 Bulging unit, 273 Annular groove, 253 Internal passage, S Reference pressure chamber.

Claims

1. An expansion valve that reduces the pressure of refrigerant introduced from an upstream side, expands the refrigerant, and discharges it to a downstream side, and controls the refrigerant flow rate so that the outlet pressure, which is the pressure of the refrigerant on the downstream side, approaches a set pressure, a body having an inlet port for introducing a refrigerant from an upstream side, an outlet port for discharging the refrigerant to a downstream side, a valve hole provided in a refrigerant passage connecting the inlet port and the outlet port, and a pressure sensing chamber into which the outlet side pressure is introduced; a valve body for adjusting the opening degree of a valve portion formed between the valve body and the valve hole; a pressure sensing section provided in the pressure sensing chamber, which senses the outlet side pressure to generate a driving force in an opening / closing direction of the valve section, and which displaces in the valve opening direction of the valve section when the outlet side pressure decreases and displaces in the valve closing direction of the valve section when the outlet side pressure increases; a solenoid including a plunger and a core, which generates a driving force in an opening / closing direction of the valve portion in accordance with a supplied current value; a valve driver that penetrates a partition wall between the refrigerant passage and the pressure sensing chamber, has one end that is operatively connectable to the pressure sensing portion and the other end that is operatively connectable to the solenoid, and is provided so that the valve body can be displaced integrally with the refrigerant passage; a biasing member that applies a biasing force in a valve closing direction to the valve driving body; Equipped with The body and the solenoid are assembled in the axial direction, The pressure sensing unit, the valve driving body, the plunger, and the core are arranged in this order from one end side of the body, the plunger is displaceable integrally with the valve driver; the solenoid generates a driving force in a valve opening direction to the valve driving element, An expansion valve characterized in that the set pressure can be changed by changing the value of the current supplied to the solenoid.

2. the outlet port communicates with an inlet of a downstream heat exchanger; 2. The expansion valve according to claim 1, wherein the pressure sensing chamber communicates with the outlet of the downstream heat exchanger.

3. 3. The expansion valve according to claim 2, wherein the downstream heat exchanger is an evaporator.

4. 3. The expansion valve according to claim 2, wherein the downstream heat exchanger is a heat exchanger for a battery.

5. An expansion valve as described in any one of claims 1 to 4, characterized in that by increasing the current value supplied to the solenoid, the valve section can be fully opened regardless of the magnitude of the outlet side pressure.

6. 6. The expansion valve according to claim 1, wherein the pressure-sensing part includes a pressure-sensing member filled with a pressure-sensing gas, and is displaced by sensing the pressure and temperature of the downstream refrigerant.

7. a compressor that compresses and discharges a refrigerant; It is located outside the vehicle cabin and functions as an external condenser that dissipates heat from the refrigerant during cooling operation. an outdoor heat exchanger that functions as an outdoor evaporator that evaporates the refrigerant during cooling operation; an interior evaporator disposed in the vehicle interior to evaporate the refrigerant; an auxiliary condenser that dissipates heat of the refrigerant separately from the outdoor heat exchanger; a first refrigerant circulation passage through which refrigerant discharged from the compressor during cooling operation can circulate so as to return to the compressor via the outdoor heat exchanger and the indoor evaporator in this order; a second refrigerant circulation passage through which the refrigerant discharged from the compressor during heating operation can circulate so as to return to the compressor via the auxiliary condenser and the outdoor heat exchanger in this order; a first valve provided in the first refrigerant circulation passage downstream of the outdoor heat exchanger, the first valve adjusting a flow rate of the refrigerant supplied to the indoor evaporator; a second valve provided in the second refrigerant circulation passage downstream of the auxiliary condenser, the second valve adjusting a flow rate of the refrigerant supplied to the outdoor heat exchanger; Equipped with the first valve and the second valve are expansion valves that reduce the pressure of the refrigerant introduced from the upstream side, expand the refrigerant, and discharge it to the downstream side, and control the refrigerant flow rate so that the outlet side pressure, which is the pressure of the refrigerant on the downstream side, approaches a set pressure; The expansion valve is a body having an inlet port for introducing a refrigerant from an upstream side, an outlet port for discharging the refrigerant to a downstream side, a valve hole provided in a refrigerant passage connecting the inlet port and the outlet port, and a pressure sensing chamber into which the outlet side pressure is introduced; a valve body for adjusting the opening degree of a valve portion formed between the valve body and the valve hole; a pressure sensing section provided in the pressure sensing chamber, which senses the outlet side pressure to generate a driving force in an opening / closing direction of the valve section, and which displaces in the valve opening direction of the valve section when the outlet side pressure decreases and displaces in the valve closing direction of the valve section when the outlet side pressure increases; a solenoid including a plunger and a core, which generates a driving force in an opening / closing direction of the valve portion in accordance with a supplied current value; a valve driver that penetrates a partition wall between the refrigerant passage and the pressure sensing chamber, has one end that is operatively connectable to the pressure sensing portion and the other end that is operatively connectable to the solenoid, and is provided so that the valve body can be displaced integrally with the refrigerant passage; a biasing member that applies a biasing force in a valve closing direction to the valve driving body; Including, The body and the solenoid are assembled in the axial direction, The pressure sensing unit, the valve driving body, the plunger, and the core are arranged in this order from one end side of the body, the plunger is displaceable integrally with the valve driver; the solenoid generates a driving force in a valve opening direction to the valve driving element, 10. A vehicle heating and cooling system, wherein the set pressure can be changed by changing the value of the current supplied to the solenoid.

8. a compressor that compresses and discharges a refrigerant; An outdoor heat exchanger; a refrigerant circulation passage through which the refrigerant discharged from the compressor can circulate so as to return to the compressor via the outdoor heat exchanger; a battery heat exchanger provided in the refrigerant circulation passage between the exterior heat exchanger and the compressor; an expansion valve provided in the refrigerant circulation passage between the exterior heat exchanger and the battery heat exchanger, which reduces the pressure of the refrigerant from the exterior heat exchanger, expands the refrigerant, and supplies it to the battery heat exchanger, and controls the refrigerant flow rate so that an outlet pressure, which is the pressure of the refrigerant on the downstream side, approaches a set pressure; Equipped with The expansion valve is a body having an inlet port for introducing a refrigerant from an upstream side, an outlet port for discharging the refrigerant to a downstream side, a valve hole provided in a refrigerant passage connecting the inlet port and the outlet port, and a pressure sensing chamber into which the outlet side pressure is introduced; a valve body for adjusting the opening degree of a valve portion formed between the valve body and the valve hole; a pressure sensing section provided in the pressure sensing chamber, which senses the outlet side pressure to generate a driving force in an opening / closing direction of the valve section, and which displaces in the valve opening direction of the valve section when the outlet side pressure decreases and displaces in the valve closing direction of the valve section when the outlet side pressure increases; a solenoid including a plunger and a core, which generates a driving force in an opening / closing direction of the valve portion in accordance with a supplied current value; a valve driver that penetrates a partition wall between the refrigerant passage and the pressure sensing chamber, has one end that is operatively connectable to the pressure sensing portion and the other end that is operatively connectable to the solenoid, and is provided so that the valve body can be displaced integrally with the refrigerant passage; a biasing member that applies a biasing force in a valve closing direction to the valve driving body; Including, The body and the solenoid are assembled in the axial direction, The pressure sensing unit, the valve driving body, the plunger, and the core are arranged in this order from one end side of the body, the plunger is displaceable integrally with the valve driver; the solenoid generates a driving force in a valve opening direction to the valve driving element, A battery cooling device characterized in that the set pressure can be changed by changing the value of the current supplied to the solenoid.

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