Refrigeration cycle equipment

Abstract

To improve the durability of gas bearings. [Solution] The compressor 12 starts when the expansion valve 14 is at the second opening, so the compression ratio of the compressor 12 is small when the compressor 12 starts. Therefore, the pressing load applied from the rotor to the gas bearing is small. The expansion valve 14 is switched to the first opening after the compressor 12 starts. Therefore, the compression ratio of the compressor 12 after starting returns to the compression ratio before the expansion valve 14 was switched to the second opening, preventing any impact on the compression efficiency of the compressor 12 after starting. The compressor 12 then stops after the expansion valve 14 is switched from the first opening to the second opening. Therefore, even if the rotational speed of the rotor falls below the levitation rotational speed as the compressor 12 tries to stop and the gas bearing supports the rotor in contact with the rotor, the pressing load applied from the rotor to the gas bearing is small.

Description

[Technical Field]

[0001] The present invention relates to a refrigeration cycle device. [Background technology]

[0002] Conventionally, refrigeration cycle devices have been known that include a refrigeration cycle configured by connecting a compressor, a condenser, an expansion valve, and an evaporator in a ring in this order. The compressor compresses and discharges a refrigerant. The condenser condenses the refrigerant discharged from the compressor. The expansion valve reduces the pressure of the refrigerant condensed by the condenser. The evaporator evaporates the refrigerant reduced in pressure by the expansion valve. The refrigeration cycle device adjusts the temperature of the temperature control target by using the refrigeration cycle to exchange heat between the refrigerant and the temperature control target via at least one of the condenser and the evaporator.

[0003] The compressor includes a housing, a rotor, and a compression section. The housing has a suction pressure region and a discharge pressure region. Refrigerant is drawn into the suction pressure region from the evaporator. Compressed refrigerant is discharged into the discharge pressure region. The rotor is housed within the housing. The compression section is driven to compress the refrigerant by rotation of the rotor.

[0004] Furthermore, compressors may also be equipped with a gas bearing, as disclosed in Patent Document 1, for example. The gas bearing rotatably supports the rotating body. The gas bearing supports the rotating body in contact with the rotating body until the rotating body reaches the levitation rotation speed. Once the rotation speed of the rotating body reaches the levitation rotation speed, the dynamic pressure of the gas film generated between the gas bearing and the rotating body causes the rotating body to levitate relative to the gas bearing. As a result, the gas bearing supports the rotating body without coming into contact with it. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-333135 Summary of the Invention [Problem to be solved by the invention]

[0006] In a refrigeration cycle, the greater the pressure difference between the first region, which is the region from the discharge pressure region to the condenser inlet, and the second region, which is the region from the evaporator outlet to the suction pressure region, the greater the compression ratio of the compressor. The greater the compression ratio of the compressor, the greater the pressing load applied from the rotating body to the gas bearing when the rotating body has not yet reached the levitation rotation speed and the gas bearing is supporting the rotating body in contact with the rotating body. The greater the pressing load applied from the rotating body to the gas bearing, the worse the durability of the gas bearing. Therefore, there is a need to improve the durability of gas bearings. [Means for solving the problem]

[0007] The refrigeration cycle device that solves the above-mentioned problems includes a refrigeration cycle configured by connecting in a ring in this order: a compressor that compresses and discharges a refrigerant; a condenser that condenses the refrigerant discharged from the compressor; an expansion valve that decompresses the refrigerant condensed by the condenser; and an evaporator that evaporates the refrigerant decompressed by the expansion valve; and the refrigeration cycle is used to perform heat exchange between the refrigerant and a temperature control target via at least one of the condenser and the evaporator, thereby adjusting the temperature of the temperature control target; and the compressor has a suction pressure region where the refrigerant from the evaporator is sucked in and a discharge pressure region where the compressed refrigerant is discharged. a housing having a region, a rotating body accommodated in the housing, a compression unit that is driven to compress a refrigerant by rotation of the rotating body, and a gas bearing that rotatably supports the rotating body, wherein the expansion valve is switchable between a first opening and a second opening that is larger than the first opening, the compressor starts when the expansion valve is at the second opening, the expansion valve switches to the first opening after the compressor is started, and the compressor stops after the expansion valve switches from the first opening to the second opening.

[0008] According to this, when the expansion valve is switched to the second opening, the pressure difference between the first region, which is the region in the refrigeration cycle from the discharge pressure region to the inlet of the condenser, and the second region, which is the region in the refrigeration cycle from the outlet of the evaporator to the suction pressure region, decreases. As a result, the compression ratio of the compressor decreases. Meanwhile, when the expansion valve is switched to the first opening, the pressure difference between the first region and the second region returns to the pressure difference before the expansion valve was switched to the second opening. Therefore, the compression ratio of the compressor returns to the compression ratio before the expansion valve was switched to the second opening.

[0009] When the compressor starts, the rotor has not yet reached the levitation rotational speed, and the gas bearing supports the rotor in contact with the rotor. The compressor starts when the expansion valve is at the second opening, so the compression ratio of the compressor is low during startup. This reduces the pressing load applied by the rotor to the gas bearing. The expansion valve switches to the first opening after the compressor starts. Therefore, the compression ratio of the compressor after startup returns to the compression ratio before the expansion valve was switched to the second opening, preventing any impact on the compression efficiency after startup. The compressor stops after the expansion valve switches from the first opening to the second opening. As the rotor's rotational speed decreases as the compressor tries to shut down, the rotor's rotational speed falls below the levitation rotational speed, and the gas bearing supports the rotor in contact with the rotor. The compressor stops when the expansion valve is switched to the second opening and the compressor's compression ratio is low. As a result, even if the rotation speed of the rotor falls below the levitation rotation speed as the compressor is about to stop and the gas bearing supports the rotor in contact with the rotor, the pressing load applied to the gas bearing from the rotor can be reduced, thereby improving the durability of the gas bearing.

[0010] In the refrigeration cycle device, the expansion valve may be configured to switch to the second opening degree when the temperature of the temperature control target increases and reaches a predetermined first threshold temperature, and to switch to the second opening degree when the temperature of the temperature control target decreases and reaches a predetermined second threshold temperature. Such a configuration is suitable for timing the switching of the expansion valve to the second opening degree.

[0011] In the refrigeration cycle device, the expansion valve may be switched from the second opening degree to the first opening degree after a predetermined time has elapsed since the compressor has started up. Such a configuration is suitable as the timing for switching the expansion valve from the second opening degree to the first opening degree after the compressor has started up.

[0012] In the refrigeration cycle device, the expansion valve may be switched from the second opening degree to the first opening degree when the rotation speed of the rotor reaches a predetermined rotation speed after the compressor is started. Such a configuration is suitable as the timing for switching the expansion valve from the second opening degree to the first opening degree after the compressor is started. [Effects of the Invention]

[0013] According to the present invention, the durability of the gas bearing can be improved. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a schematic diagram showing the configuration of a refrigeration cycle device according to a first embodiment. [Figure 2] FIG. 2 is a schematic diagram showing the configuration of the compressor. [Figure 3] FIG. 3 is an enlarged cross-sectional view of a portion of the compressor. [Figure 4] FIG. 4 is a graph showing the battery cooling mode. [Figure 5] FIG. 5 is a graph showing the battery warm-up mode. [Figure 6] FIG. 6 is a schematic diagram showing the configuration of a refrigeration cycle device according to the second embodiment. [Figure 7] FIG. 7 is a graph showing the battery cooling mode. [Figure 8] FIG. 8 is a graph showing the battery warm-up mode. [Figure 9] FIG. 9 is an enlarged cross-sectional view showing a part of the compressor in the modified example. DETAILED DESCRIPTION OF THE INVENTION

[0015] [First embodiment] A first embodiment of a refrigeration cycle device will be described below with reference to Figures 1 to 5. The refrigeration cycle device of the first embodiment is mounted on, for example, a fuel cell vehicle.

[0016] <Basic configuration of refrigeration cycle equipment> 1, the refrigeration cycle device 10 includes a refrigeration cycle 11. The refrigeration cycle 11 includes a compressor 12, a first heat exchanger 13, an expansion valve 14, and a second heat exchanger 15.

[0017] The compressor 12 and the first heat exchanger 13 are connected by a first pipe 16. A first end of the first pipe 16 is connected to a discharge port 12a of the compressor 12. A second end of the first pipe 16 is connected to an inlet 13a of the first heat exchanger 13.

[0018] The first heat exchanger 13 and the expansion valve 14 are connected by a second pipe 17. A first end of the second pipe 17 is connected to the outlet 13b of the first heat exchanger 13. A second end of the second pipe 17 is connected to the inlet 14a of the expansion valve 14.

[0019] The expansion valve 14 and the second heat exchanger 15 are connected by a third pipe 18. A first end of the third pipe 18 is connected to the outlet 14b of the expansion valve 14. A second end of the third pipe 18 is connected to the inlet 15a of the second heat exchanger 15.

[0020] The second heat exchanger 15 and the compressor 12 are connected by a fourth pipe 19. A first end of the fourth pipe 19 is connected to the outlet 15b of the second heat exchanger 15. A second end of the fourth pipe 19 is connected to the suction port 12b of the compressor 12.

[0021] In this way, the refrigeration cycle 11 is configured by connecting the compressor 12, the first heat exchanger 13, the expansion valve 14, and the second heat exchanger 15 in this order in a ring shape. The refrigerant flowing through the refrigeration cycle 11 flows through the compressor 12, the first heat exchanger 13, the expansion valve 14, and the second heat exchanger 15 in this order.

[0022] An accumulator (not shown) is provided in the fourth pipe 19. The accumulator allows gaseous refrigerant to flow into the compressor 12 and prevents liquid refrigerant from flowing into the compressor 12.

[0023] The refrigeration cycle apparatus 10 includes a first heat medium circuit 20 and a second heat medium circuit 30. The first heat medium circuit 20 includes a first heat medium heat exchanger 21 and a first heat medium pump 22. A heat medium flows through the first heat medium circuit 20. The heat medium flowing through the first heat medium circuit 20 is, for example, water. In the first heat medium circuit 20, the heat medium is circulated by driving the first heat medium pump 22. The first heat medium circuit 20 is connected to a first heat exchanger 13. The heat medium flowing through the first heat medium circuit 20 is capable of exchanging heat with a refrigerant via the first heat exchanger 13. The first heat medium heat exchanger 21 is thermally coupled to a battery 40, the temperature of which is to be regulated. The heat medium flowing through the first heat medium heat exchanger 21 is capable of exchanging heat with the battery 40.

[0024] The second heat medium circuit 30 has a second heat medium heat exchanger 31 and a second heat medium pump 32. A heat medium flows through the second heat medium circuit 30. The heat medium flowing through the second heat medium circuit 30 is, for example, water. In the second heat medium circuit 30, the heat medium is circulated by driving the second heat medium pump 32. The second heat medium circuit 30 is connected to a second heat exchanger 15. The heat medium flowing through the second heat medium circuit 30 is capable of exchanging heat with a refrigerant via the second heat exchanger 15. The second heat medium heat exchanger 31 is thermally coupled to the battery 40. The heat medium flowing through the second heat medium heat exchanger 31 is capable of exchanging heat with the battery 40.

[0025] The first heat exchanger 13 is configured to be switchable between a first state in which heat is exchanged between the refrigerant flowing through the first heat exchanger 13 and the outside air, and a second state in which heat is exchanged between the refrigerant flowing through the first heat exchanger 13 and the heat medium flowing through the first heat medium circuit 20.

[0026] The second heat exchanger 15 is configured to be switchable between a first state in which heat is exchanged between the refrigerant flowing through the second heat exchanger 15 and the outside air, and a second state in which heat is exchanged between the refrigerant flowing through the second heat exchanger 15 and the heat medium flowing through the second heat medium circuit 30.

[0027] <Compressor> 2, compressor 12 includes a housing 50, a rotor 51, a compression unit 52, a motor 53, and a gas bearing 54. Housing 50 is cylindrical. Housing 50 accommodates rotor 51, compression unit 52, motor 53, and gas bearing 54. Therefore, rotor 51 is accommodated within housing 50.

[0028] The rotating body 51 includes a rotating shaft 55 and a thrust collar 56. The rotating shaft 55 is rotated by the drive of the motor 53. The thrust collar 56 is disk-shaped. The thrust collar 56 is fixed to the rotating shaft 55 by being press-fitted onto the outer circumferential surface of the rotating shaft 55. The thrust collar 56 protrudes from the outer circumferential surface of the rotating shaft 55 in the radial direction of the rotating shaft 55.

[0029] Gas bearing 54 includes two radial bearings 57 and two thrust bearings 58. The two radial bearings 57 and the two thrust bearings 58 are held in housing 50. The two radial bearings 57 are arranged on both sides of motor 53. The two radial bearings 57 rotatably support portions of rotating shaft 55 on both sides of motor 53. The two radial bearings 57 support rotating body 51 rotatably in the radial direction. The "radial direction" refers to a direction perpendicular to the axial direction of rotating shaft 55.

[0030] The two thrust bearings 58 are arranged at positions sandwiching the thrust collar 56 in the axial direction of the rotating shaft 55. The two thrust bearings 58 support the thrust collar 56 rotatably in the thrust direction. Note that the "thrust direction" is the axial direction of the rotating shaft 55. In this way, the gas bearings 54 rotatably support the rotating body 51.

[0031] Gas bearing 54 supports rotor 51 while in contact with rotor 51 until rotor 51 reaches the levitation rotation speed. When the rotation speed of rotor 51 reaches the levitation rotation speed, dynamic pressure of a gas film generated between gas bearing 54 and rotor 51 causes rotor 51 to levitate relative to gas bearing 54. As a result, gas bearing 54 supports rotor 51 without coming into contact with rotor 51.

[0032] The compression unit 52 is fixed to an end of the rotary shaft 55. The compression unit 52 is an impeller that rotates integrally with the rotary shaft 55. Therefore, the compressor 12 of this embodiment is a centrifugal compressor. The compression unit 52 is driven by the rotation of the rotor 51 to compress the refrigerant.

[0033] As shown in FIG. 3, the compressor 12 includes an impeller chamber 59, a diffuser passage 60, and a discharge chamber 61. The impeller chamber 59 houses the compression section 52. The impeller chamber 59 communicates with the suction port 12b. The suction port 12b extends in the axial direction of the housing 50. The discharge chamber 61 extends around the axis of the suction port 12b around the periphery of the impeller chamber 59. The diffuser passage 60 communicates between the impeller chamber 59 and the discharge chamber 61. The discharge chamber 61 communicates with the discharge port 12a.

[0034] The refrigerant drawn into the suction port 12b from the fourth pipe 19 is sent from the impeller chamber 59 to the diffuser passage 60 by the drive of the compression section 52, and is pressurized in the diffuser passage 60. Then, the air that has passed through the diffuser passage 60 is discharged into the discharge chamber 61. The refrigerant discharged into the discharge chamber 61 is discharged into the first pipe 16 through the discharge port 12a.

[0035] The suction port 12b is a suction pressure region 62 into which the refrigerant is drawn from the second heat exchanger 15. The discharge chamber 61 and the discharge port 12a are a discharge pressure region 63 into which the compressed refrigerant is discharged. Therefore, the compressor 12 has the suction pressure region 62 into which the refrigerant is drawn from the second heat exchanger 15 and the discharge pressure region 63 into which the compressed refrigerant is discharged.

[0036] <First and second areas> The discharge chamber 61, the discharge port 12a, the first pipe 16, and the inlet 13a of the first heat exchanger 13 form a first region 64 in the refrigeration cycle 11, which is a region from the discharge pressure region 63 to the inlet 13a of the first heat exchanger 13. The outlet 15b of the second heat exchanger 15, the fourth pipe 19, and the suction port 12b form a second region 65 in the refrigeration cycle 11, which is a region from the outlet 15b of the second heat exchanger 15 to the suction pressure region 62. Therefore, the refrigeration cycle 11 has the first region 64, which is a region from the discharge pressure region 63 to the inlet 13a of the first heat exchanger 13, and the second region 65, which is a region from the outlet 15b of the second heat exchanger 15 to the suction pressure region 62.

[0037] <Bypass passage> As shown in FIG. 1 , the refrigeration cycle apparatus 10 includes a bypass passage 70. The bypass passage 70 is, for example, a pipe. A first end of the bypass passage 70 is connected to the first pipe 16. A second end of the bypass passage 70 is connected to the fourth pipe 19. Therefore, the bypass passage 70 connects the first region 64 and the second region 65 in the refrigeration cycle 11. The bypass passage 70 causes the refrigerant flowing through the first pipe 16 to flow into the fourth pipe 19. Therefore, the bypass passage 70 causes the refrigerant in the first region 64 to flow to the second region 65.

[0038] <Switching valve> The refrigeration cycle apparatus 10 includes a switching valve 71. The switching valve 71 is provided in the bypass passage 70. The switching valve 71 is, for example, an on-off valve. The switching valve 71 is a solenoid valve. When the switching valve 71 is in an open state, it allows refrigerant to flow from the first pipe 16 to the fourth pipe 19 via the bypass passage 70. On the other hand, when the switching valve 71 is in a closed state, it blocks refrigerant from flowing from the first pipe 16 to the fourth pipe 19 via the bypass passage 70. Thus, the switching valve 71 is configured to be switchable between a permissive state in which it allows refrigerant to flow from the first pipe 16 to the fourth pipe 19 via the bypass passage 70 and a blocking state in which it blocks refrigerant from flowing from the first pipe 16 to the fourth pipe 19 via the bypass passage 70. Therefore, the switching valve 71 can be switched between an allowable state in which the refrigerant flows from the first region 64 to the second region 65 via the bypass passage 70, and a blocking state in which the refrigerant flows from the first region 64 to the second region 65 via the bypass passage 70.

[0039] <Control> The refrigeration cycle apparatus 10 includes a control device 80. The control device 80 includes a central processing unit (CPU). The control device 80 includes a memory configured of a read-only memory (ROM) in which various programs, maps, etc. are stored in advance, and a random access memory (RAM) for temporarily storing the results of CPU calculations, etc. The control device 80 includes a timer counter, an input interface, an output interface, etc.

[0040] The refrigeration cycle device 10 includes a temperature sensor 81. The temperature sensor 81 is configured to be able to detect the temperature of the battery 40. The temperature sensor 81 is electrically connected to the control device 80. A detection signal relating to the temperature of the battery 40 detected by the temperature sensor 81 is transmitted to the control device 80.

[0041] The refrigeration cycle apparatus 10 includes a rotation speed sensor 82. The rotation speed sensor 82 is configured to be able to detect the rotation speed of the rotor 51 of the compressor 12. The rotation speed sensor 82 is electrically connected to the control device 80. A detection signal relating to the rotation speed of the rotor 51 of the compressor 12 detected by the rotation speed sensor 82 is transmitted to the control device 80.

[0042] The control device 80 is electrically connected to the compressor 12. The control device 80 controls the driving of the compressor 12. The control device 80 stores in advance a compressor driving program that transmits command signals to the compressor 12 to command the starting and stopping of the compressor 12. The compressor 12 starts when it receives a start command signal from the control device 80, and stops when it receives a stop command signal from the control device 80.

[0043] The control device 80 is electrically connected to the first heat medium pump 22. The control device 80 controls the operation of the first heat medium pump 22. The control device 80 is electrically connected to the second heat medium pump 32. The control device 80 controls the operation of the second heat medium pump 32.

[0044] The control device 80 can switch the refrigeration cycle device 10 between a battery cooling mode for cooling the battery 40 and a battery warming mode for warming the battery 40. In the battery cooling mode, the first heat exchanger 13 is switched to the first state, and the second heat exchanger 15 is switched to the second state. In the battery warming mode, the first heat exchanger 13 is switched to the second state, and the second heat exchanger 15 is switched to the first state.

[0045] The control device 80 stores in advance a program that, in the battery cooling mode, stops the operation of the first heat medium pump 22 and operates the second heat medium pump 32. Therefore, in the battery cooling mode, the heat medium does not circulate in the first heat medium circuit 20, but circulates in the second heat medium circuit 30.

[0046] The control device 80 stores in advance a program that, in the battery warm-up mode, drives the first heat medium pump 22 and stops driving the second heat medium pump 32. Therefore, in the battery warm-up mode, the heat medium circulates in the first heat medium circuit 20, but does not circulate in the second heat medium circuit 30.

[0047] FIG. 4 is a graph showing the temperature of the battery 40, the on / off state of the compressor 12, and the open / close state of the switching valve 71 when the refrigeration cycle device 10 is switched to the battery cooling mode by the control device 80.

[0048] As shown in Fig. 4, in the compressor drive program in the battery cooling mode, when the temperature of the battery 40 detected by the temperature sensor 81 rises and reaches a preset control temperature Tmax, a command signal to start the compressor 12 is sent to the compressor 12. In the compressor drive program in the battery cooling mode, when the temperature of the battery 40 detected by the temperature sensor 81 falls and reaches a preset control temperature Tmin, a command signal to stop the compressor 12 is sent to the compressor 12.

[0049] FIG. 5 is a graph showing the temperature of the battery 40, the on / off state of the compressor 12, and the open / close state of the switching valve 71 when the refrigeration cycle device 10 is switched to the battery warm-up mode by the control device 80.

[0050] 5, in the compressor drive program in the battery warm-up mode, when the temperature of the battery 40 detected by the temperature sensor 81 rises and reaches a preset control temperature Tmax, a command signal to stop the compressor 12 is sent to the compressor 12. In the compressor drive program in the battery warm-up mode, when the temperature of the battery 40 detected by the temperature sensor 81 falls and reaches a preset control temperature Tmin, a command signal to start the compressor 12 is sent to the compressor 12.

[0051] The control device 80 is electrically connected to the switching valve 71. The control device 80 has a valve drive program stored in advance that controls the drive of the switching valve 71. As shown in FIGS. 4 and 5 , the valve drive program switches the switching valve 71 to the open state in both the battery cooling mode and the battery warming mode when the temperature of the battery 40 detected by the temperature sensor 81 increases and reaches a preset first threshold temperature Tx1. The "first threshold temperature Tx1" is a temperature slightly lower than the control temperature Tmax. The valve drive program switches the switching valve 71 to the open state in both the battery cooling mode and the battery warming mode when the temperature of the battery 40 detected by the temperature sensor 81 decreases and reaches a preset second threshold temperature Tx2. The "second threshold temperature Tx2" is a temperature slightly higher than the control temperature Tmin. Therefore, the switching valve 71 switches to an allowable state when the temperature of the battery 40 rises and reaches a predetermined first threshold temperature Tx1, and switches to an allowable state when the temperature of the battery 40 falls and reaches a predetermined second threshold temperature Tx2.

[0052] In the valve drive program, in both the battery cooling mode and the battery warming mode, the compressor 12 switches from the open state to the closed state after a predetermined time has elapsed since startup. Therefore, the switching valve 71 switches from the open state to the shutoff state after a predetermined time has elapsed since startup of the compressor 12. In this way, the compressor 12 starts when the switching valve 71 is in the open state, and the switching valve 71 switches to the shutoff state after startup of the compressor 12. Note that the "predetermined time" here refers to the time it is assumed that the rotor 51 has reached the levitation rotation speed since startup of the compressor 12. This predetermined time is determined in advance, for example, by experimentation.

[0053] In the battery cooling mode, after the compressor 12 is started, when the temperature of the battery 40 detected by the temperature sensor 81 drops and reaches the second threshold temperature Tx2, the switching valve 71 switches from the shutoff state to the open state, and the compressor 12 stops after the switching valve 71 switches from the shutoff state to the open state. In the battery warm-up mode, after the compressor 12 is started, when the temperature of the battery 40 detected by the temperature sensor 81 rises and reaches the first threshold temperature Tx1, the switching valve 71 switches from the shutoff state to the open state, and the compressor 12 stops after the switching valve 71 switches from the shutoff state to the open state. In this way, the compressor 12 starts when the switching valve 71 is in the open state, and the switching valve 71 switches to the shutoff state after the compressor 12 is started, and the compressor 12 stops after the switching valve 71 switches from the shutoff state to the open state.

[0054] In the valve drive program, in both the battery cooling mode and the battery warming mode, the state is switched from the open state to the closed state after a predetermined time has elapsed since the compressor 12 stopped. Therefore, the switching valve 71 is switched from the open state to the shutoff state after a predetermined time has elapsed since the compressor 12 stopped. Note that the "predetermined time" here refers to the time it is assumed that the rotor 51 of the compressor 12 has completely stopped after the compressor 12 receives a stop command signal from the control device 80. This predetermined time is determined in advance, for example, by experiment.

[0055] In the battery warm-up mode, if the temperature of the battery 40 is below the control temperature Tmin when the refrigeration cycle device 10 starts operating, the compressor 12 is started and the switching valve 71 is in the allowable state. Then, the switching valve 71 switches from the allowable state to the shut-off state after a predetermined time has elapsed since the refrigeration cycle device 10 started operating.

[0056] <Battery cooling mode> For example, assume that the refrigeration cycle apparatus 10 is switched to the battery cooling mode by the control device 80. The compressor 12 compresses a low-temperature, low-pressure refrigerant and discharges a high-temperature, high-pressure gas refrigerant. Therefore, the compressor 12 compresses and discharges the refrigerant. The gas refrigerant discharged from the discharge port 12a of the compressor 12 into the first pipe 16 is supplied to the first heat exchanger 13 via the first pipe 16 and the inlet 13a of the first heat exchanger 13.

[0057] In the battery cooling mode, the first heat exchanger 13 is switched to the first state, and the gas refrigerant supplied to the first heat exchanger 13 is condensed and liquefied by heat exchange with the outside air via the first heat exchanger 13. Therefore, the first heat exchanger 13 functions as a condenser that condenses the refrigerant discharged from the compressor 12.

[0058] The high-temperature, high-pressure liquid refrigerant condensed and liquefied in the first heat exchanger 13 flows into the second pipe 17 via the outlet 13b of the first heat exchanger 13, and passes through the expansion valve 14 via the second pipe 17 and the inlet 14a of the expansion valve 14. The liquid refrigerant passing through the expansion valve 14 is decompressed by the expansion valve 14, becoming a low-temperature, low-pressure liquid refrigerant. Therefore, the expansion valve 14 decompresses the refrigerant condensed in the first heat exchanger 13.

[0059] The low-temperature, low-pressure liquid refrigerant decompressed by the expansion valve 14 flows from the outlet 14b of the expansion valve 14 into the third pipe 18 and is supplied to the second heat exchanger 15 via the third pipe 18 and the inlet 15a of the second heat exchanger 15. In the battery cooling mode, the second heat exchanger 15 is switched to the second state, and the liquid refrigerant flowing through the second heat exchanger 15 evaporates by heat exchange with the heat medium flowing through the second heat medium circuit 30. Therefore, the second heat exchanger 15 functions as an evaporator that evaporates the refrigerant decompressed by the expansion valve 14.

[0060] The heat medium flowing through the second heat medium circuit 30 dissipates heat to the liquid refrigerant in the second heat exchanger 15. This cools the heat medium flowing through the second heat medium circuit 30. As a result, the batteries 40 are cooled by the heat medium flowing through the second heat medium circuit 30 through heat exchange via the second heat medium heat exchanger 31.

[0061] The refrigerant that has flowed through the second heat exchanger 15 flows from the outlet 15b of the second heat exchanger 15 into the fourth pipe 19, and is sucked into the compressor 12 through the fourth pipe 19 and the suction port 12b of the compressor 12.

[0062] <Battery warm-up mode> For example, assume that the refrigeration cycle apparatus 10 is switched to the battery warm-up mode by the control device 80. The compressor 12 compresses a low-temperature, low-pressure refrigerant and discharges a high-temperature, high-pressure gas refrigerant. The gas refrigerant discharged from the discharge port 12a of the compressor 12 into the first pipe 16 is supplied to the first heat exchanger 13 via the first pipe 16 and the inlet 13a of the first heat exchanger 13.

[0063] In the battery warm-up mode, the first heat exchanger 13 is switched to the second state, and the gas refrigerant supplied to the first heat exchanger 13 is condensed and liquefied by heat exchange with the heat medium flowing through the first heat medium circuit 20 via the first heat exchanger 13.

[0064] The heat medium flowing through the first heat medium circuit 20 absorbs heat from the gas refrigerant in the first heat exchanger 13. This warms the heat medium flowing through the first heat medium circuit 20. As a result, the battery 40 is warmed by the heat medium flowing through the first heat medium circuit 20 through heat exchange with the heat medium via the first heat medium heat exchanger 21. In this way, the refrigeration cycle device 10 uses the refrigeration cycle 11 to exchange heat between the refrigerant and the battery 40 through the first heat exchanger 13 and the second heat exchanger 15, thereby regulating the temperature of the battery 40.

[0065] The high-temperature, high-pressure liquid refrigerant that has been condensed and liquefied in the first heat exchanger 13 flows into the second pipe 17 via the outlet 13b of the first heat exchanger 13, and passes through the expansion valve 14 via the second pipe 17 and the inlet 14a of the expansion valve 14. The liquid refrigerant passing through the expansion valve 14 is decompressed by the expansion valve 14, and becomes a low-temperature, low-pressure liquid refrigerant.

[0066] The low-temperature, low-pressure liquid refrigerant decompressed by the expansion valve 14 flows from the outlet 14b of the expansion valve 14 into the third pipe 18 and is supplied to the second heat exchanger 15 via the third pipe 18 and the inlet 15a of the second heat exchanger 15. In the battery warm-up mode, the second heat exchanger 15 is switched to the first state, and the liquid refrigerant flowing through the second heat exchanger 15 evaporates by exchanging heat with the outside air. The refrigerant that has flowed through the second heat exchanger 15 flows from the outlet 15b of the second heat exchanger 15 into the fourth pipe 19 and is drawn into the compressor 12 via the fourth pipe 19 and the inlet 12b of the compressor 12.

[0067] [Operation of the first embodiment] Next, the operation of the first embodiment will be described. In refrigeration cycle 11, the greater the pressure difference between first region 64 and second region 65, the greater the compression ratio of compressor 12. Here, the greater the compression ratio of compressor 12, the greater the pressing load applied from rotor 51 to gas bearing 54 when rotor 51 has not yet reached the levitation rotation speed and gas bearing 54 is supporting rotor 51 in contact with rotor 51.

[0068] When the switching valve 71 is switched to the permissive state, the flow of refrigerant from the first region 64 to the second region 65 via the bypass passage 70 is permitted, and the pressure difference between the first region 64 and the second region 65 decreases. This reduces the compression ratio of the compressor 12. On the other hand, when the switching valve 71 is switched to the blocked state, the flow of refrigerant from the first region 64 to the second region 65 via the bypass passage 70 is blocked, and the pressure difference between the first region 64 and the second region 65 returns to the pressure difference before the switching valve 71 was switched to the permissive state. This returns the compression ratio of the compressor 12 to the compression ratio before the switching valve 71 was switched to the permissive state.

[0069] Here, when compressor 12 is started, rotor 51 has not yet reached the levitation rotation speed, and gas bearing 54 supports rotor 51 in a state of contact with rotor 51. As shown in Figures 4 and 5, compressor 12 starts when switching valve 71 is in the permissive state, and therefore the compression ratio of compressor 12 is small when compressor 12 is started. Therefore, the pressing load applied from rotor 51 to gas bearing 54 is small.

[0070] The switching valve 71 switches to the shutoff state after the compressor 12 is started. Therefore, the compression ratio of the compressor 12 after the compressor 12 is started returns to the compression ratio before the switching valve 71 was switched to the permitting state, thereby preventing any effect on the compression efficiency of the compressor 12 after the compressor 12 is started. The compressor 12 then stops after the switching valve 71 switches from the shutoff state to the permitting state. Here, when the rotation speed of the rotor 51 decreases as the compressor 12 tries to stop, the rotation speed of the rotor 51 falls below the levitation rotation speed, and the gas bearing 54 supports the rotor 51 in a state of contact with the rotor 51. The compressor 12 stops with the switching valve 71 switched to the permitting state and the compression ratio of the compressor 12 low. Therefore, even if the rotation speed of the rotor 51 falls below the levitation rotation speed when the compressor 12 is about to stop and the gas bearing 54 supports the rotor 51 in a state of contact with the rotor 51, the pressing load applied from the rotor 51 to the gas bearing 54 becomes smaller.

[0071] [Effects of the first embodiment] The first embodiment can provide the following effects. (1-1) Because the compressor 12 starts when the switching valve 71 is in the permissive state, the compression ratio of the compressor 12 is small when the compressor 12 starts. This reduces the pressing load applied from the rotor 51 to the gas bearing 54. The switching valve 71 switches to the shutoff state after the compressor 12 starts. This returns the compression ratio of the compressor 12 after the compressor 12 starts to the compression ratio before the switching valve 71 was switched to the permissive state, preventing any impact on the compression efficiency of the compressor 12 after the compressor 12 starts. The compressor 12 then stops after the switching valve 71 switches from the shutoff state to the permissive state. Here, as the rotational speed of the rotor 51 decreases as the compressor 12 tries to stop, the rotational speed of the rotor 51 falls below the levitation rotational speed, and the gas bearing 54 comes into contact with the rotor 51 and supports the rotor 51. Compressor 12 stops with the compression ratio of compressor 12 low after switching valve 71 switches to the permissive state. Therefore, even if the rotation speed of rotor 51 falls below the levitation rotation speed as compressor 12 tries to stop and gas bearing 54 supports rotor 51 in a state of contact with rotor 51, the pressing load applied from rotor 51 to gas bearing 54 can be reduced. As a result, the durability of gas bearing 54 can be improved.

[0072] (1-2) The switching valve 71 switches to the permissive state when the temperature of the battery 40 rises and reaches a predetermined first threshold temperature Tx1, and switches to the permissive state when the temperature of the battery 40 drops and reaches a predetermined second threshold temperature Tx2. This configuration is suitable for timing the switching of the switching valve 71 to the permissive state.

[0073] (1-3) The switching valve 71 switches from the permitting state to the blocking state a predetermined time after the compressor 12 starts up. This configuration is suitable for timing the switching valve 71 to switch from the permitting state to the blocking state after the compressor 12 starts up.

[0074] [Second embodiment] A second embodiment of a refrigeration cycle device will be described below with reference to Figures 6 to 8. In the embodiment described below, the same components as those in the first embodiment already described will be denoted by the same reference numerals, and redundant description will be omitted or simplified. The second embodiment differs from the first embodiment in that the refrigeration cycle device does not include a bypass passage or a switching valve, and a control device controls the opening of an expansion valve.

[0075] 6, the expansion valve 14 is a proportional valve. The expansion valve 14 is a solenoid valve. The expansion valve 14 is switchable between a first opening and a second opening that is larger than the first opening.

[0076] FIG. 7 is a graph showing the temperature of the battery 40, the on / off state of the compressor 12, and the opening state of the expansion valve 14 when the refrigeration cycle device 10 is switched to the battery cooling mode by the control device 80.

[0077] FIG. 8 is a graph showing the temperature of the battery 40, the on / off state of the compressor 12, and the opening state of the expansion valve 14 when the refrigeration cycle device 10 is switched to the battery warm-up mode by the control device 80.

[0078] The control device 80 is electrically connected to the expansion valve 14. The control device 80 has a valve opening adjustment program stored in advance to adjust the opening of the expansion valve 14. As shown in FIGS. 7 and 8 , the valve opening adjustment program switches to the second opening in both the battery cooling mode and the battery warming mode when the temperature of the battery 40 detected by the temperature sensor 81 rises and reaches a predetermined first threshold temperature Tx1. The valve drive program switches to the second opening in both the battery cooling mode and the battery warming mode when the temperature of the battery 40 detected by the temperature sensor 81 drops and reaches a predetermined second threshold temperature Tx2. Therefore, the expansion valve 14 switches to the second opening when the temperature of the battery 40 rises and reaches the predetermined first threshold temperature Tx1, and switches to the second opening when the temperature of the battery 40 drops and reaches the predetermined second threshold temperature Tx2.

[0079] In the valve opening adjustment program, in both the battery cooling mode and the battery warming mode, the compressor 12 switches from the second opening to the first opening after a predetermined time has elapsed since startup. Therefore, the expansion valve 14 switches from the second opening to the first opening after a predetermined time has elapsed since startup of the compressor 12. In this way, the compressor 12 starts when the expansion valve 14 is at the second opening, and the expansion valve 14 switches to the first opening after startup of the compressor 12. Note that the "predetermined time" here refers to the time it is assumed that the rotor 51 has reached the levitation rotation speed since startup of the compressor 12. This predetermined time is determined in advance, for example, by experimentation.

[0080] In the battery cooling mode, after the compressor 12 is started, when the temperature of the battery 40 detected by the temperature sensor 81 drops and reaches the second threshold temperature Tx2, the expansion valve 14 switches from the first opening to the second opening, and the compressor 12 stops after the expansion valve 14 switches from the first opening to the second opening. In the battery warming mode, after the compressor 12 is started, when the temperature of the battery 40 detected by the temperature sensor 81 rises and reaches the first threshold temperature Tx1, the switching valve 71 switches from the first opening to the second opening, and the compressor 12 stops after the expansion valve 14 switches from the first opening to the second opening. In this way, the compressor 12 starts when the expansion valve 14 is at the second opening degree, and the expansion valve 14 switches to the first opening degree after the compressor 12 starts, and the compressor 12 stops after the expansion valve 14 switches from the first opening degree to the second opening degree.

[0081] In the valve opening adjustment program, in both the battery cooling mode and the battery warming mode, the valve opening is switched from the second opening to the first opening after a predetermined time has elapsed since the compressor 12 stopped. Note that the "predetermined time" here refers to the time it is assumed that the rotor 51 of the compressor 12 has completely stopped after the compressor 12 receives a stop command signal from the control device 80. This predetermined time is determined in advance, for example, by experiment.

[0082] The expansion valve 14 is fully closed when the operation of the refrigeration cycle apparatus 10 is stopped. In the battery warm-up mode, if the temperature of the battery 40 is below the control temperature Tmin when the operation of the refrigeration cycle apparatus 10 is started, the compressor 12 is started and the expansion valve 14 is opened at the second degree of opening. The expansion valve 14 is then switched from the second degree of opening to the first degree of opening after a predetermined time has elapsed since the operation of the refrigeration cycle apparatus 10 was started.

[0083] [Operation of the second embodiment] Next, the operation of the second embodiment will be described. When the expansion valve 14 switches to the second opening, the pressure difference between the first region 64 and the second region 65 decreases. As a result, the compression ratio of the compressor 12 decreases. On the other hand, when the expansion valve 14 switches to the first opening, the pressure difference between the first region 64 and the second region 65 returns to the pressure difference before the expansion valve 14 was switched to the second opening. Therefore, the compression ratio of the compressor 12 returns to the compression ratio before the expansion valve 14 was switched to the second opening.

[0084] Here, when compressor 12 is started, rotor 51 has not yet reached the levitation rotation speed, and gas bearing 54 supports rotor 51 in a state of contact with rotor 51. As shown in Figures 7 and 8, compressor 12 starts when expansion valve 14 is at the second opening, and therefore the compression ratio of compressor 12 is small when compressor 12 is started. Therefore, the pressing load applied from rotor 51 to gas bearing 54 is small.

[0085] The expansion valve 14 switches to the first opening degree after the compressor 12 is started. Therefore, the compression ratio of the compressor 12 after the compressor 12 is started returns to the compression ratio before the expansion valve 14 was switched to the second opening degree, thereby preventing any effect on the compression efficiency of the compressor 12 after the compressor 12 is started. The compressor 12 then stops after the expansion valve 14 switches from the first opening degree to the second opening degree. Here, when the rotation speed of the rotor 51 decreases as the compressor 12 tries to stop, the rotation speed of the rotor 51 falls below the levitation rotation speed, and the gas bearing 54 supports the rotor 51 in a state where it is in contact with the rotor 51. The compressor 12 stops when the expansion valve 14 switches to the second opening degree and the compression ratio of the compressor 12 is small. Therefore, even if the rotation speed of the rotor 51 falls below the levitation rotation speed when the compressor 12 is about to stop and the gas bearing 54 supports the rotor 51 in a state of contact with the rotor 51, the pressing load applied from the rotor 51 to the gas bearing 54 becomes smaller.

[0086] [Effects of the second embodiment] In the second embodiment, the following effects can be obtained. (2-1) Because the compressor 12 starts when the expansion valve 14 is at the second opening, the compression ratio of the compressor 12 is small when the compressor 12 starts. This reduces the pressing load applied from the rotor 51 to the gas bearing 54. The expansion valve 14 switches to the first opening after the compressor 12 starts. This returns the compression ratio of the compressor 12 after the compressor 12 starts to the compression ratio before the expansion valve 14 was switched to the second opening, preventing any impact on the compression efficiency of the compressor 12 after the compressor 12 starts. The compressor 12 then stops after the expansion valve 14 switches from the first opening to the second opening. When the rotation speed of the rotor 51 decreases as the compressor 12 tries to stop, the rotation speed of the rotor 51 falls below the levitation rotation speed, and the gas bearing 54 comes into contact with the rotor 51 and supports the rotor 51. Compressor 12 stops with expansion valve 14 switched to the second opening and the compression ratio of compressor 12 low. Therefore, even if the rotation speed of rotor 51 falls below the levitation rotation speed as compressor 12 tries to stop and gas bearing 54 supports rotor 51 in a state of contact with rotor 51, the pressing load applied from rotor 51 to gas bearing 54 can be reduced. As a result, the durability of gas bearing 54 can be improved.

[0087] (2-2) The expansion valve 14 switches to the second opening degree when the temperature of the battery 40 rises and reaches a predetermined first threshold temperature Tx1, and switches to the second opening degree when the temperature of the battery 40 falls and reaches a predetermined second threshold temperature Tx2. This configuration is suitable for timing the expansion valve 14 to switch to the second opening degree.

[0088] (2-3) The expansion valve 14 switches from the second opening degree to the first opening degree after a predetermined time has elapsed since the start of the compressor 12. This configuration is suitable as the timing for switching the expansion valve 14 from the second opening degree to the first opening degree after the start of the compressor 12.

[0089] [Example of change] The above-described embodiments can be modified as follows: The above-described embodiments and the following modifications can be combined with each other within the scope of technical compatibility.

[0090] In the first embodiment, the valve drive program may switch from the open state to the closed state when the rotation speed of the rotor 51 detected by the rotation speed sensor 82 reaches a predetermined rotation speed after the compressor 12 starts, in both the battery cooling mode and the battery warming mode. The "predetermined rotation speed" here refers to the floating rotation speed of the rotor 51. This predetermined rotation speed is determined in advance, for example, through experimentation. In this manner, the switching valve 71 may switch from the open state to the shutoff state when the rotation speed of the rotor 51 reaches the predetermined rotation speed after the compressor 12 starts. This configuration is suitable for determining the timing for switching the switching valve 71 from the open state to the shutoff state after the compressor 12 starts.

[0091] In the second embodiment, the valve opening adjustment program may switch from the second opening to the first opening in both the battery cooling mode and the battery warming mode when the rotation speed of the rotor 51 detected by the rotation speed sensor 82 reaches a predetermined rotation speed after the compressor 12 is started. The "predetermined rotation speed" here refers to the floating rotation speed of the rotor 51. This predetermined rotation speed is determined in advance, for example, through experiments. In this way, the expansion valve 14 may switch from the second opening to the first opening when the rotation speed of the rotor 51 reaches the predetermined rotation speed after the compressor 12 is started. This configuration is suitable for timing the expansion valve 14 to switch from the second opening to the first opening after the compressor 12 is started.

[0092] 9 , for example, a bypass passage 70 may be formed in the housing 50. A switching valve 71 is provided in the bypass passage 70. The bypass passage 70 connects, for example, the discharge port 12a and the suction port 12b. In short, the bypass passage 70 only needs to connect the first region 64 and the second region 65 in the refrigeration cycle 11.

[0093] In the first embodiment, the valve drive program may maintain the open state after the compressor 12 is stopped in both the battery cooling mode and the battery warming mode. In other words, the switching valve 71 may maintain the open state after the compressor 12 is stopped.

[0094] In the second embodiment, the valve opening adjustment program may maintain the second opening degree after the compressor 12 is stopped in both the battery cooling mode and the battery warming mode. In each of the above embodiments, the refrigeration cycle apparatus 10 may be configured without the first heat medium circuit 20 and the second heat medium circuit 30. For example, the battery 40, the temperature of which is to be controlled, may be thermally coupled to the second heat exchanger 15. In this case, when cooling the battery 40, the refrigerant flows through the compressor 12, the first heat exchanger 13, the expansion valve 14, and the second heat exchanger 15 in this order in the refrigeration cycle 11. In this way, the first heat exchanger 13 functions as a condenser, and the second heat exchanger 15 functions as an evaporator. On the other hand, when warming the battery 40, the refrigerant flows through the compressor 12, the second heat exchanger 15, the expansion valve 14, and the first heat exchanger 13 in this order in the refrigeration cycle 11. In this way, the first heat exchanger 13 functions as an evaporator, and the second heat exchanger 15 functions as a condenser. In this configuration, the refrigeration cycle 11 includes a four-way valve for switching the flow of the refrigerant. In short, the refrigeration cycle device 10 is configured to be able to adjust the temperature of the temperature control object by using the refrigeration cycle 11 to perform heat exchange between the refrigerant and the temperature control object via at least one of a condenser and an evaporator.

[0095] In the first embodiment, for example, the switching valve 71 may be a three-way valve provided at a connection point between the first pipe 16 and the bypass passage 70. In short, the switching valve 71 may be configured to be switchable between a permissive state in which the refrigerant flows from the first region 64 to the second region 65 via the bypass passage 70, and a blocking state in which the refrigerant flows from the first region 64 to the second region 65 via the bypass passage 70.

[0096] In the first embodiment, the switching valve 71 may be a mechanical valve. In the second embodiment, the expansion valve 14 may be a mechanical type. In the second embodiment, the expansion valve 14 may be fully open when the operation of the refrigeration cycle apparatus 10 is stopped.

[0097] In each of the above-described embodiments, the compression unit 52 does not have to be an impeller. For example, the compression unit 52 may be a scroll type or a vane type. In short, the type of the compressor 12 is not particularly limited.

[0098] In each of the above-described embodiments, the target of temperature control by the refrigeration cycle device 10 is not limited to the battery 40, and may be, for example, the indoor air of a vehicle. In each of the above-described embodiments, the refrigeration cycle apparatus 10 does not have to be mounted on a fuel cell vehicle. In other words, the refrigeration cycle apparatus 10 is not limited to being mounted on a vehicle.

[0099] The technical ideas that can be understood from the above-described embodiment and modified examples will be described. (A) A refrigeration cycle comprising a compressor that compresses and discharges a refrigerant, a condenser that condenses the refrigerant discharged from the compressor, an expansion valve that decompresses the refrigerant condensed by the condenser, and an evaporator that evaporates the refrigerant decompressed by the expansion valve, all connected in this order in a ring, wherein the refrigeration cycle is used to exchange heat between the refrigerant and a temperature control target via at least one of the condenser and the evaporator, thereby adjusting the temperature of the temperature control target, and the compressor comprises a housing having a suction pressure region where the refrigerant from the evaporator is sucked in and a discharge pressure region where the compressed refrigerant is discharged, a rotor housed in the housing, a compression section that is driven to compress the refrigerant by rotation of the rotor, and a gas bearing that rotatably supports the rotor. a first region that is a region between the discharge pressure region and the inlet of the condenser, and a second region that is a region between the outlet of the evaporator and the suction pressure region; a bypass passage that connects the first region and the second region; and a switching valve that is switchable between a permissive state that allows refrigerant to flow from the first region to the second region via the bypass passage and a blocking state that blocks refrigerant from flowing from the first region to the second region via the bypass passage, wherein the compressor starts when the switching valve is in the permissive state, and the switching valve switches to the blocking state after the compressor starts, and the compressor stops after the switching valve switches from the blocking state to the permissive state.

[0100] According to the above configuration, when the switching valve is switched to the permissive state, refrigerant is permitted to flow from the first region to the second region via the bypass passage, thereby reducing the pressure difference between the first region and the second region. This reduces the compression ratio of the compressor. On the other hand, when the switching valve is switched to the blocked state, refrigerant is prevented from flowing from the first region to the second region via the bypass passage, thereby restoring the pressure difference between the first region and the second region to the pressure difference before the switching valve was switched to the permissive state. This returns the compression ratio of the compressor to the compression ratio before the switching valve was switched to the permissive state.

[0101] Here, when the compressor starts, the rotor has not yet reached the levitation rotational speed, and the gas bearing supports the rotor in contact with the rotor. Because the compressor starts when the switching valve is in the permissive state, the compression ratio of the compressor is low at the start of the compressor. This reduces the pressing load applied from the rotor to the gas bearing. The switching valve switches to the shutoff state after the compressor starts. Therefore, the compression ratio of the compressor after the compressor starts returns to the compression ratio before the switching valve was switched to the permissive state, preventing any impact on the compression efficiency after the compressor starts. The compressor then stops after the switching valve switches from the shutoff state to the permissive state. Here, as the rotational speed of the rotor decreases as the compressor tries to stop, the rotational speed of the rotor falls below the levitation rotational speed, and the gas bearing supports the rotor in contact with the rotor. The compressor stops when the switching valve switches to the permissive state and the compression ratio of the compressor is low. As a result, even if the rotation speed of the rotor falls below the levitation rotation speed as the compressor is about to stop and the gas bearing supports the rotor in contact with the rotor, the pressing load applied to the gas bearing from the rotor can be reduced, thereby improving the durability of the gas bearing.

[0102] (B) In the above refrigeration cycle device, the switching valve may be configured to switch to the permissive state when the temperature of the temperature control target rises and reaches a predetermined first threshold temperature, and to switch to the permissive state when the temperature of the temperature control target falls and reaches a predetermined second threshold temperature. Such a configuration is suitable for timing the switching of the switching valve to the permissive state.

[0103] (C) In the above refrigeration cycle apparatus, the switching valve may be switched from the permitting state to the blocking state after a predetermined time has elapsed since the compressor has started up. Such a configuration is suitable for timing the switching valve from the permitting state to the blocking state after the compressor has started up.

[0104] (D) In ​​the above refrigeration cycle apparatus, the switching valve may be switched from the permitting state to the blocking state when the rotation speed of the rotor reaches a predetermined rotation speed after the compressor is started. Such a configuration is suitable for timing the switching valve from the permitting state to the blocking state after the compressor is started. [Explanation of symbols]

[0105] 10...refrigeration cycle device, 11...refrigeration cycle, 12...compressor, 13...first heat exchanger functioning as a condenser, 13a...inlet, 14...expansion valve, 15...second heat exchanger functioning as an evaporator, 15b...outlet, 40...battery to be temperature-controlled, 50...housing, 51...rotating body, 52...compression section, 54...gas bearing, 62...suction pressure region, 63...discharge pressure region, 64...first region, 65...second region, 70...bypass passage, 71...switching valve.

Claims

1. a compressor that compresses and discharges a refrigerant; a condenser that condenses the refrigerant discharged from the compressor; an expansion valve that reduces the pressure of the refrigerant condensed in the condenser; an evaporator that evaporates the refrigerant decompressed by the expansion valve; and a refrigeration cycle configured by connecting these in a ring in this order, Using the refrigeration cycle, heat exchange is performed between the refrigerant and a temperature control target via at least one of the condenser and the evaporator, thereby adjusting the temperature of the temperature control target; The compressor is a housing having a suction pressure region into which the refrigerant from the evaporator is drawn and a discharge pressure region into which the compressed refrigerant is discharged; a rotating body accommodated in the housing; a compression unit that is driven to compress the refrigerant by rotation of the rotor; a gas bearing that rotatably supports the rotating body, the expansion valve is switchable between a first opening degree and a second opening degree that is larger than the first opening degree; The refrigeration cycle device is characterized in that the compressor starts when the expansion valve is at the second opening degree, and the expansion valve switches to the first opening degree after the compressor is started, and the compressor stops after the expansion valve switches from the first opening degree to the second opening degree.

2. 2. The refrigeration cycle device according to claim 1, wherein the expansion valve switches to the second opening degree when the temperature of the temperature-controlled object rises and reaches a predetermined first threshold temperature, and switches to the second opening degree when the temperature of the temperature-controlled object falls and reaches a predetermined second threshold temperature.

3. 3. The refrigeration cycle device according to claim 1, wherein the expansion valve switches from the second opening degree to the first opening degree after a predetermined time has elapsed since the compressor was started.

4. 3. The refrigeration cycle device according to claim 1, wherein the expansion valve switches from the second opening degree to the first opening degree when the rotation speed of the rotor reaches a predetermined rotation speed after the compressor is started.

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