Flow path switching valve and refrigeration device

Abstract

This flow path switching valve comprises an accommodating body (31) and a valve body (60), wherein: first, second, and third refrigerant flow paths providing communication between a valve chamber (31A) within the accommodating body (31) and the outside of the accommodating body (31) are formed in the accommodating body (31); the valve body (60) has a first passage (61) which connects the first and second refrigerant flow paths in a first orientation, connects the first and third refrigerant flow paths in a second orientation, and through which refrigerant at a first pressure flows, and a second passage (62) which communicates with the third refrigerant flow path in the first orientation and communicates with the second refrigerant flow path in the second orientation, and through which refrigerant at a second pressure higher than the first pressure flows; the valve chamber (31A) and the second passage (62) communicate with each other when the valve body (60) is in the first orientation or the second orientation; and the flow path switching valve is provided with a pressure equalization mechanism (80) that can be switched between a mode for connecting the first passage (61) and the valve chamber (31A) and a mode for releasing the connection, and that is capable of connecting the first passage (61) and the valve chamber (31A) when the valve body (60) is in the first orientation or the second orientation.

Description

Flow path switching valve and refrigeration device

[0001] The present disclosure relates to a flow path switching valve and a refrigeration device.

[0002] Patent Document 1 below discloses a multi-directional ball valve that functions as a three-way valve or a four-way valve and alternately switches a certain fluid system to a plurality of fluid systems. This multi-directional ball valve includes a casing, a valve ball housed in the casing, and a valve seat that supports the outer peripheral surface of the valve ball. The valve ball is rotatably supported by the valve seat. Three or four inlets / outlets are formed in the casing, and one or two valve holes are formed in the valve ball. By rotating the valve ball, one end of one or two valve holes can be aligned with one or two inlets / outlets, and the other end of the valve hole can be aligned with another inlet / outlet, thereby switching the fluid path.

[0003] Japanese Patent Application Laid-Open No. 59-13170

[0004] When using the multi-directional ball valve described in Patent Document 1 to switch the flow path of high-pressure fluid, for example, the refrigerant flowing through a refrigeration device, high pressure is applied not only inside but also on the outer surface of the valve ball. Therefore, the valve ball is strongly pressed against the valve seat, and it is necessary to rotate the valve body with high torque to switch the flow path. Therefore, a high-output motor or a speed reducer with a high reduction ratio is required, which causes the flow path switching valve to become larger and more expensive.

[0005] An object of the present disclosure is to provide a flow path switching valve and a refrigeration device that can reduce the torque for rotating the valve body.

[0006] (1) The flow path switching valve of the present disclosure comprises: a housing having a valve chamber inside; a valve body rotatably housed in the valve chamber and switchable between a first position and a second position by rotation; the housing has a first refrigerant flow path, a second refrigerant flow path, and a third refrigerant flow path formed therein, connecting the valve chamber to the outside of the housing; the valve body has a first passage through which refrigerant at a first pressure flows, connecting the first refrigerant flow path and the second refrigerant flow path in the first position and connecting the first refrigerant flow path and the third refrigerant flow path in the second position; a second passage through which refrigerant at a second pressure higher than the first pressure flows, communicating with the third refrigerant flow path in the first position and communicating with the second refrigerant flow path in the second position; the valve chamber and the second passage communicate with each other when the valve body is in the first position or the second position. The valve body is equipped with a pressure equalization mechanism that can switch between a mode in which the first passage and the valve chamber are connected and a mode in which the connection is released, and which can connect the first passage and the valve chamber when the valve body is in the first or second position.

[0007] According to the above configuration, by connecting the first flow path and the valve chamber with a pressure equalization mechanism, high-pressure (second pressure) refrigerant and low-pressure (first pressure) refrigerant can be mixed within the flow path switching valve, and the pressure can be balanced (equalized). As a result, the torque required to rotate the valve body can be reduced, and the motor and speed control mechanism can be miniaturized.

[0008] (2) In the flow path switching valve of (1) above, a fourth refrigerant flow path is formed in the housing that connects the valve chamber and the outside of the housing, and the second passage connects the third refrigerant flow path and the fourth refrigerant flow path in the first position, and connects the second refrigerant flow path and the fourth refrigerant flow path in the second position.

[0009] With this configuration, high-pressure refrigerant can be flowed through the second passage, and the flow path switching valve can be used as a four-way switching valve.

[0010] (3) In the flow path switching valve of (1) or (2) above, the pressure equalization mechanism includes a pressure equalization flow path connecting the first passage and the valve chamber, and an opening / closing mechanism for opening and closing the pressure equalization flow path.

[0011] This configuration allows for the mixing of high-pressure and low-pressure refrigerants through a pressure equalization channel.

[0012] (4) The flow path switching valve described in (3) above is provided with an operating mechanism for rotating the valve body, the operating mechanism includes a drive shaft positioned on the rotation axis of the valve body, the valve body has a connecting portion to which the drive shaft is connected and to which the pressure equalization flow path is formed, and the opening / closing mechanism opens and closes the pressure equalization flow path by moving the drive shaft.

[0013] With this configuration, the opening and closing mechanism can be constructed using the drive shaft that constitutes the operating mechanism.

[0014] (5) In the flow path switching valve described in (4) above, the operating mechanism includes a drive unit that rotates the drive shaft for the rotation of the valve body, and the opening and closing mechanism opens and closes the pressure equalizing flow path using the rotation of the drive shaft by the drive unit.

[0015] With this configuration, the opening and closing mechanism can be constructed using the drive shaft and drive unit that constitute the operating mechanism. Therefore, a drive unit dedicated to the opening and closing mechanism can be omitted.

[0016] (6) In the flow path switching valve described in (5) above, the opening and closing mechanism has a conversion unit that converts the rotation of the drive shaft by the drive unit into movement of the drive shaft in the axial direction, and the pressure equalizing flow path is opened and closed by moving the drive shaft in the axial direction with the conversion unit.

[0017] With this configuration, the rotation of the drive shaft by the drive unit is used to move the drive shaft axially, thereby opening and closing the pressure equalization flow path.

[0018] (7) In the flow path switching valve described in (6) above, the conversion unit has a cam surface provided on one of the connecting unit and the drive shaft, the axial position of which varies in the circumferential direction of the drive shaft, and a cam receiving unit provided on the other of the connecting unit and the drive shaft, which contacts the cam surface.

[0019] With this configuration, the drive shaft can be rotated to move the drive shaft axially along the cam surface, thereby opening and closing the pressure equalization passage.

[0020] (8) In the flow path switching valve of (6) or (7) above, the drive shaft has an axial end face that closes the pressure equalizing flow path.

[0021] With this configuration, the pressure equalization channel can be easily opened and closed by the axial movement of the drive shaft.

[0022] (9) In the flow path switching valve described in (5) above, a communication passage communicating with the valve chamber is formed in a part of the circumferential direction of the drive shaft, and the opening and closing mechanism rotates the drive shaft by the drive unit to a rotation position that connects the communication passage to the pressure equalizing flow path and a rotation position that disconnects the communication.

[0023] With this configuration, the pressure equalization channel can be opened and closed by rotating the drive shaft.

[0024] (10) In the flow path switching valve described in (5) above, the opening and closing mechanism includes a closing member that closes the pressure equalization flow path and moves by the rotation of the drive shaft, and the opening and closing mechanism rotates the drive shaft by the drive unit to a rotation position in which the pressure equalization flow path is closed by the closing member and a rotation position in which the closure is released.

[0025] With this configuration, the pressure equalization channel can be opened and closed by rotating the drive shaft.

[0026] (11) The refrigeration apparatus of the present disclosure comprises a refrigerant circuit including a flow path switching valve as described in any one of (1) to (10) above.

[0027] (12) The refrigeration apparatus described in (11) above includes a control unit that controls the pressure equalization mechanism of the flow path switching valve, and when the control unit receives a signal to rotate the valve body, it controls the pressure equalization mechanism to connect the first passage and the valve chamber for a predetermined time while the valve body is in the first or second position.

[0028] This configuration allows for sufficient pressure equalization between high-pressure and low-pressure refrigerants, reducing the torque required to rotate the valve body.

[0029] Figure 1 is a diagram showing the refrigerant circuit of a refrigeration system including a flow path switching valve according to the first embodiment of the present disclosure. Figure 2 is a plan view showing the interior of the outdoor unit. Figure 3 is a front view showing the machine room of the outdoor unit. Figure 4 is a perspective view of the flow path switching valve. Figure 5 is a perspective view of the valve body and drive shaft of the flow path switching valve. Figure 6A is a cross-sectional view taken along the line E-E in Figure 4, illustrating the operation of the flow path switching valve in the first embodiment. Figure 6B is a cross-sectional view taken along the line E-E in Figure 4, illustrating the operation of the flow path switching valve in the second embodiment. Figure 7 is a front view of the valve body. Figure 8 is a view taken along the line F in Figure 7. Figure 9 is a front view showing the end face of the drive shaft on the valve body side. Figure 10 is a view taken along the line G in Figure 9. Figure 11 is a schematic explanatory diagram of the flow path switching valve showing a state in which the pressure equalization mechanism is not operating. Figure 12 is a schematic explanatory diagram of the flow path switching valve showing a state in which the pressure equalization mechanism is operating. Figure 13A is an explanatory diagram showing the operation flow of the flow path switching valve. Figure 13B is a flowchart showing the control procedure of the control unit related to switching operations. Figure 13C is a flowchart showing the control procedure of the control unit related to switching operations in a modified example. Figure 14 is a perspective view showing the valve body and drive shaft in the second embodiment. Figure 15 is a front view of the valve body and drive shaft. Figure 16 is a schematic explanatory diagram of the flow path switching valve showing the state in which the pressure equalization mechanism is not acting. Figure 17 is a schematic explanatory diagram of the flow path switching valve showing the state in which the pressure equalization mechanism is acting. Figure 18A is an explanatory diagram showing the operation flow of the flow path switching valve. Figure 18B is an explanatory diagram showing the operation flow of the flow path switching valve. Figure 19A is a schematic explanatory diagram of the flow path switching valve showing the state in which the pressure equalization mechanism is not acting in the third embodiment. Figure 19B is a plan view showing the positional relationship between the pressure equalization flow path and the closing member in the state shown in Figure 19A. Figure 20A is a schematic explanatory diagram of the flow path switching valve showing the state in which the pressure equalization mechanism is acting in the third embodiment. Figure 20B is a plan view showing the positional relationship between the pressure equalization flow path and the closing member in the state shown in Figure 20A. Figure 21 is a perspective view of the valve body. Figure 22 is a perspective view of the drive shaft. Figure 23A is an explanatory diagram showing the operation flow of the flow path switching valve. Figure 23B is an explanatory diagram showing the operation flow of the flow path switching valve. Figure 24 is a flowchart showing the control procedure of the control unit related to switching operations.

[0030] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the attached drawings. Figure 1 is a diagram showing a refrigerant circuit of a refrigeration system including a flow path switching valve according to the first embodiment of the present disclosure. The refrigeration system 10 is equipped with a refrigerant circuit 30 that performs vapor compression type refrigeration cycle operation. The refrigeration system 10 of this embodiment is an air conditioner. As shown in Figure 1, this air conditioner 10 has an outdoor unit (heat source unit) 11 and an indoor unit (utilization unit) 12. The outdoor unit 11 and the indoor unit 12 are connected by connecting pipes 13 and 14, respectively. The refrigerant circuit 30 is formed by the outdoor unit 11, the indoor unit 12, and the connecting pipes 13 and 14. In the outdoor unit 11, shut-off valves 23 and 24 are provided at the connection part of the connecting pipes 13 and 14. Note that the refrigeration system 10 is not limited to an air conditioner, but may be a refrigerator, freezer, water heater, ventilation system, etc.

[0031] (Refrigerant Circuit Configuration) As shown in Figure 1, the outdoor unit 11 is equipped with a compressor 15, an accumulator 25, an outdoor heat exchanger (heat source heat exchanger) 16, an expansion valve 17, and a four-way switching valve (flow path switching valve) 18, which constitute the refrigerant circuit 30. The outdoor unit 11 is also equipped with an outdoor fan 19. The indoor unit 12 is equipped with an indoor heat exchanger (utilizing heat exchanger) 21, which constitutes the refrigerant circuit 30. The indoor unit 12 is also equipped with an indoor fan 22.

[0032] The four-way switching valve 18 in this embodiment has four ports A to D, and is unitized including refrigerant passages 51b, 52b, 53b, and 56b that communicate with these ports A to D. The compressor 15 is a positive displacement compressor, such as a scroll type or rotary type, and has a built-in compressor motor. The compressor 15 compresses the refrigerant drawn in from the suction pipe 52a and then discharges it from the discharge pipe 51a.

[0033] In the outdoor unit 11, the discharge side of the compressor 15 is connected to the refrigerant flow path 51b and port A of the four-way switching valve 18 via the discharge pipe 51a, which is a refrigerant pipe. The refrigerant flow path 51b is provided with a check valve 71 to suppress backflow of refrigerant. The suction side of the compressor 15 is connected to the refrigerant flow path 52b and port B of the four-way switching valve 18 via the suction pipe 52a, which is a refrigerant pipe. An accumulator 25 is provided in the middle of the suction pipe 52a.

[0034] The outdoor heat exchanger 16 is composed of a cross-fin type fin-and-tube heat exchanger or a microchannel type heat exchanger, etc. The gas side end of the outdoor heat exchanger 16 is connected to the refrigerant flow path 53b and port C of the four-way switching valve 18 via refrigerant piping 53a. The liquid side end of the outdoor heat exchanger 16 is connected to one end of the expansion valve 17 via refrigerant piping 54. A strainer (filter) 72 for removing foreign matter from the refrigerant is provided in this refrigerant piping 54.

[0035] The expansion valve 17 is, for example, an electrically operated valve with an adjustable opening. The other end of the expansion valve 17 is connected to the liquid side shut-off valve 23 via the refrigerant piping 55. The refrigerant piping 55 is provided with a strainer 72 for removing foreign matter from the refrigerant.

[0036] The indoor heat exchanger 21 is composed of a cross-fin type fin-and-tube heat exchanger or a microchannel type heat exchanger, etc. The liquid side end of the indoor heat exchanger 21 is connected to the liquid side shut-off valve 23 via the liquid side connecting pipe 14. The gas side end of the indoor heat exchanger 21 is connected to the gas side shut-off valve 24 via the gas side connecting pipe 13. The gas side shut-off valve 24 is connected to the refrigerant flow path 56b and port D of the four-way switching valve 18 via the refrigerant pipe 56a.

[0037] The four-way switching valve 18 switches the flow path between a first mode (shown by a solid line in Figure 1) in which ports A and C are in communication with each other and ports B and D are in communication with each other, and a second mode (shown by a dotted line in Figure 1) in which ports A and D are in communication with each other and ports B and C are in communication with each other. In the first mode, the refrigerant discharged from the compressor 15 flows to the outdoor heat exchanger 16, and in the second mode, the refrigerant discharged from the compressor 15 flows to the indoor heat exchanger 21.

[0038] The outdoor fan 19 is positioned near the outdoor heat exchanger 16. The outdoor fan 19 is driven to rotate by a motor and blows air to the outdoor heat exchanger 16. The refrigerant flowing through the outdoor heat exchanger 16 exchanges heat with the outdoor air supplied by the outdoor fan 19, resulting in evaporation (heat absorption) or condensation (heat release).

[0039] The indoor fan 22 is positioned near the indoor heat exchanger 21. The indoor fan 22 is driven by a motor to rotate and blow air into the indoor heat exchanger 21. The refrigerant flowing through the indoor heat exchanger 21 exchanges heat with the indoor air supplied by the indoor fan 22, resulting in condensation (heat dissipation) or evaporation (heat absorption).

[0040] The air conditioner 10 switches the four-way diverter valve 18 to a first mode when performing cooling operation, and switches the four-way diverter valve 18 to a second mode when performing heating operation. In cooling operation, the gaseous refrigerant discharged from the compressor 15 flows into the outdoor heat exchanger 16, which functions as a condenser, via the four-way diverter valve 18, and is condensed into liquid refrigerant. This liquid refrigerant is depressurized in the expansion valve 17 to become a gas-liquid two-phase refrigerant and flows into the indoor heat exchanger 21, which functions as an evaporator. The gas-liquid two-phase refrigerant exchanges heat with the air supplied by the indoor fan 22 and evaporates, becoming a gaseous refrigerant. The air cooled by heat exchange is supplied to the room. The gaseous refrigerant flowing out of the indoor heat exchanger 21 is drawn into the compressor 15 via the four-way diverter valve 18.

[0041] During heating operation, the gaseous refrigerant discharged from the compressor 15 flows into the indoor heat exchanger 21, which functions as a condenser, via the four-way switching valve 18. The gaseous refrigerant exchanges heat with the air supplied by the indoor fan 22 and condenses to become liquid refrigerant. The air heated by the heat exchange is supplied to the room. The liquid refrigerant flowing out of the indoor heat exchanger 21 is depressurized in the expansion valve 17 to become a gas-liquid two-phase refrigerant and flows into the outdoor heat exchanger 16, which functions as an evaporator. The gas-liquid two-phase refrigerant evaporates in the outdoor heat exchanger 16 and becomes gaseous refrigerant. The gaseous refrigerant is drawn into the compressor 15 via the four-way switching valve 18.

[0042] Furthermore, when the air conditioner 10 performs a defrost operation to melt frost accumulated on the outdoor heat exchanger 16 during heating operation, it switches the four-way directional valve 18 from the second mode to the first mode. When the air conditioner 10 stops heating operation, it switches the four-way directional valve 18 from the second mode to the first mode.

[0043] The air conditioner 10 includes a control unit 20 that controls a compressor 15, a four-way switching valve 18, an expansion valve 17, fans 19, 22, etc. in order to perform the above-described cooling operation, heating operation, etc. The control unit 20 controls various devices based on, for example, an instruction to start or stop operation input to a remote controller or the like, an instruction to switch the operation such as cooling and heating, and set values of the indoor temperature or air volume. Note that the control unit 20 has a processor and a storage unit. The processor includes a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), etc. However, the processor may be an ASIC (Application Specific Integrated Circuit) or a programmable logic device such as a gate array or an FPGA (Field Programmable Gate Array). The ASIC or the programmable logic device is configured to be able to execute the same processing as the control program. The storage unit includes a volatile memory such as a SRAM (Static Random Access Memory) or a DRAM (Dynamic Random Access Memory), and a non-volatile memory such as a flash memory, a hard disk, or a ROM (Read Only Memory). The non-volatile memory stores a control program, which is a computer program, and control data. The control unit 20 exhibits various functions when the processor executes the control program stored in the storage unit.

[0044] (Structure of Outdoor Unit) FIG. 2 is a plan view showing the inside of the outdoor unit. FIG. 3 is a front view showing the machine room of the outdoor unit. In the following description, in FIGS. 2 and 3, the direction indicated by arrow X (first direction X) is the left-right direction, the direction indicated by arrow Y (second direction Y) is the front-back direction, and the direction indicated by arrow Z (third direction Z) is the up-down direction. However, the directions indicated by these arrows X, Y, and Z are merely examples and can be changed as appropriate.

[0045] The outdoor unit 11 includes a casing 91. The casing 91 is formed in a rectangular parallelepiped shape and is rectangular in plan view. The interior of the casing 91 is partitioned by a partition wall 92 into a machine room S1 and a heat exchange room S2. The compressor 15 is housed in the machine room S1. In addition to the compressor 15, an accumulator 25, a four-way switching valve 18, etc. are also housed in the machine room S1.

[0046] In the heat exchange room S2 of the casing 91, an outdoor heat exchanger 16, an outdoor fan 19, etc. are housed. The outdoor heat exchanger 16 is formed in an L shape in plan view. The outdoor heat exchanger 16 is arranged along two adjacent side walls (rear side wall 91a, left side wall 91b) of the casing 91 arranged on the heat exchange room S2 side. Air inlets 91a1, 91b1 are formed in these side walls 91a, 91b. The outdoor fan 19 is arranged to face another side wall (front side wall) 91c adjacent to one side wall (left side wall) 91b in which the air inlet 91b1 is formed. An air outlet 91c1 is formed in this side wall 91c.

[0047] When the outdoor fan 19 operates, air is taken into the casing 91 from the air inlets 91a1, 91b1 and discharged from the air outlet 91c1. The arrow a shown in FIG. 2 indicates the direction of the air flow taken into the casing 91.

[0048] As shown in FIGS. 2 and 3, the four-way switching valve 18 is arranged in the machine room S1 of the casing 91 of the outdoor unit 11. Specifically, the four-way switching valve 18 is arranged in the machine room S1 in the vicinity of side walls (front side wall) 91c and side wall (right side wall) 91d adjacent to each other. In other words, the four-way switching valve 18 is arranged at the corner portion between the side walls 91c, 91d.

[0049] The four-way diverter valve 18 is fixed to the casing 91 by mounting members 93 and 94. Mounting member 93 is formed, for example, in the shape of a strip, with one end in the longitudinal direction fixed to the four-way diverter valve 18 and the other end fixed to the partition wall 92 of the casing 91. Mounting member 94 is fixed, for example, with one end fixed to the side wall (right side wall) 91d of the casing 91 and the other end fixed to the four-way diverter valve 18. Therefore, the four-way diverter valve 18 is mounted between the side wall 91d of the casing 91 and the partition wall 92 in the left-right direction X via mounting members 93 and 94. The four-way diverter valve 18 is located on the right side of the compressor 15 (one side in the first direction X) and in front of the accumulator 25 (one side in the second direction Y).

[0050] In this embodiment, one end of each of the refrigerant pipes 51a, 52a, 53a, and 56a is connected to the four-way switching valve 18. Of these, the other end of the refrigerant pipe (discharge pipe) 51a is connected to the discharge side of the compressor 15. The other end of the refrigerant pipe (suction pipe) 52a is connected to the accumulator 25. The other end of the refrigerant pipe 53a is connected to the outdoor heat exchanger 16. The other end of the refrigerant pipe 56a is connected to the shut-off valve 24.

[0051] (Flow path switching valve) Figure 4 is a perspective view of the flow path switching valve. Figure 5 is a perspective view of the valve body and drive shaft of the flow path switching valve. Figure 6A is a cross-sectional view taken along the line E-E in Figure 4, illustrating the operation of the flow path switching valve in the first embodiment. Figure 6B is a cross-sectional view taken along the line E-E in Figure 4, illustrating the operation of the flow path switching valve in the second embodiment. As shown in Figure 4, the flow path switching valve 18 of this embodiment has a valve body 40A and a drive mechanism 40B. The valve body 40A is formed in a substantially cylindrical shape as a whole. The central axis C1 of the cylindrical shape of the valve body 40A is oriented in the vertical direction. Therefore, "vertical direction" in the following description of the valve body 40A means the direction along the central axis C1. The drive mechanism 40B is provided on the outer circumferential surface of the valve body 40A.

[0052] As shown in Figures 6A and 6B, the valve body 40A comprises a housing 31 and a valve body 60. The housing 31 has a substantially cylindrical outer shape. The housing 31 includes a flow path section 32 made of synthetic resin and a metal casing 33. Multiple refrigerant flow paths 51b, 52b, 53b, 56b, and 31A are formed in the flow path section 32. Of these, the refrigerant flow path 31A substantially constitutes a "valve chamber" in which the valve body 60 is housed, and refrigerant flows through passages 61 and 62 formed in the valve body 60. The refrigerant flow paths 51b, 52b, 53b, and 56b are denoted by the same reference numerals as the refrigerant flow paths in Figure 1.

[0053] The flow channel portion 32 of the containment body 31 is made of synthetic resin. The flow channel portion 32 is formed by mold molding such as injection molding. Materials such as PA66 (polyamide 66), PPS (polyphenylene sulfide), and PBT (polybutylene terephthalate) are used as the material for the flow channel portion 32.

[0054] The refrigerant passages 51b, 52b, 53b, and 56b each have one end communicating with the valve chamber 31A and the other end opening on the surface of the passage section 32. In particular, the upper ends of the refrigerant passages 51b and 56b communicate with the valve chamber 31A and the lower ends opening on the lower surface of the passage section 32. The lower ends of the refrigerant passages 52b and 53b communicate with the valve chamber 31A and the upper ends opening on the upper surface of the passage section 32.

[0055] The casing 33 covers the outside of the flow path section 32. The casing 33 is formed in a substantially cylindrical shape with both ends closed in the axial direction. The casing 33 is composed of two components 33A and 33B that are divided in the middle of the cylindrical shape in the axial direction. The casing 33 is made of steel material. For example, the casing 33 is made of stainless steel. Each component 33A and 33B of the casing 33 is formed by metalworking such as sheet metal processing and press working. For example, each component 33A and 33B is formed by deep drawing. However, the material and manufacturing method of the casing 33 are not limited to those described above. For example, the casing 33 may be made of other steel materials such as iron or a material mainly composed of aluminum (pure aluminum or aluminum alloy).

[0056] The two components 33A and 33B of the casing 33 are joined by welding. Specifically, the two components 33A and 33B of the casing 33 are joined by welding that involves melting the base material. The two components 33A and 33B are tightly joined to prevent refrigerant leakage between them. The casing 33 protects the flow path section 32 by covering the outside of the flow path section 32. The casing 33 enhances the pressure resistance of the flow path section 32 against the pressure applied by the refrigerant in the refrigerant flow paths 51b, 52b, 53b, 56b, and 31A. The casing 33 prevents refrigerant leaking from the flow path section 32 from leaking to the outside.

[0057] The valve body 60 of the four-way directional control valve 18 is housed within the housing 31. Therefore, the housing 31 also functions as the casing for the valve body 60 in the four-way directional control valve 18. More specifically, the flow path portion 32 of the housing 31 functions as the inner casing for the valve body 60, and the casing 33 of the housing 31 functions as the outer casing for the valve body 60.

[0058] The housing 31 has a plurality of joint pipes 51d, 52d, 53d, and 56d provided on the upper and lower surfaces of the casing 33. These joint pipes 51d, 52d, 53d, and 56d are inserted into openings 51c, 52c, 53c, and 56c formed on the upper and lower surfaces of the casing 33 and fixed to the casing 33 by welding or the like. For example, the joint pipes 51d, 52d, 53d, and 56d are joined to the casing 33 by brazing, a type of welding that does not involve melting the base material. The ends of the joint pipes 51d, 52d, 53d, and 56d are also inserted into the refrigerant flow paths 51b, 52b, 53b, and 56b.

[0059] The fittings 51d, 52d, 53d, and 56d in this embodiment are made of a material mainly composed of copper (such as a copper alloy or pure copper). However, the material of the fittings 51d, 52d, 53d, and 56d is not limited to this, and they may be made of other materials such as a material mainly composed of aluminum or stainless steel.

[0060] The valve chamber 31A, which houses the valve body 60, is spherical in shape. Multiple ports (openings) A, B, C, and D are formed on the inner surface of the valve chamber 31A. These ports A to D correspond to the ports A to D described with reference to Figure 1. Two ports B and C are located on the upper side of the valve chamber 31A, and two ports A and D are located on the lower side of the valve chamber 31A.

[0061] The housing 31 has refrigerant flow paths 51b, 52b, 53b, and 56b that communicate with ports A to D. The refrigerant flow path 51b that communicates with port A extends approximately downward from port A. The end (upper end) of the fitting pipe 51d is inserted into the lower end of the refrigerant flow path 51b. The refrigerant piping 51a (see Figure 1) is connected to the fitting pipe 51d.

[0062] The refrigerant flow path 51b has an annular protrusion 51e in its middle. A check valve 71 is housed in the refrigerant flow path 51b below the protrusion 51e. The check valve 71 is a non-electric component incorporated into the refrigerant flow path 51b. The check valve 71 restricts the flow of refrigerant from the valve body 60 side to the joint pipe 51d side and allows the flow of refrigerant in the reverse direction. The check valve 71 is a functional component that operates with respect to the refrigerant flowing through the refrigerant flow path 51b. The specific structure of the check valve 71 is not particularly limited, and a known structure can be adopted.

[0063] The refrigerant flow path 52b, which communicates with port B, extends approximately upward from port B. The end (lower end) of the fitting pipe 52d is inserted into the upper end of the refrigerant flow path 52b. The refrigerant piping 52a (see Figure 1) is connected to the fitting pipe 52d.

[0064] The refrigerant flow path 53b, which communicates with port C, extends approximately upward from port C. The end (lower end) of the fitting pipe 53d is inserted into the upper end of the refrigerant flow path 53b. The refrigerant piping 53a (see Figure 1) is connected to the fitting pipe 53d.

[0065] The refrigerant flow path 56b, which communicates with port D, extends approximately downward from port D. The end (upper end) of the fitting pipe 56d is inserted into the lower end of the refrigerant flow path 56b. The refrigerant piping 56a (see Figure 1) is connected to the fitting pipe 56d.

[0066] The flow path section 32 of the housing 31 is equipped with a sealing member 32G at the end of the refrigerant flow paths 51b, 52b, 53b, and 56b opposite to the valve chamber 31A side, and the ends of the joint pipes 51d, 52d, 53d, and 56d are also inserted into this sealing member 32G. The sealing member 32G suppresses refrigerant leakage from between the refrigerant flow paths 51b, 52b, 53b, and 56b and the joint pipes 51d, 52d, 53d, and 56d by bringing its inner circumference 37a into contact with the joint pipes 51d, 52d, 53d, and 56d.

[0067] As shown in Figures 5, 6A, and 6B, the valve body 60 is formed in a spherical shape. The valve body 60 is positioned in the valve chamber 31A of the housing 31. The outer diameter of the valve body 60 is formed to be slightly smaller than the inner diameter of the inner surface of the valve chamber 31A.

[0068] The valve body 60 is made of metal or synthetic resin. The valve body 60 is manufactured, for example, by die casting or injection molding. Examples of materials used for the valve body 60 include aluminum alloys, pure aluminum, and other aluminum-based materials, steel materials such as SUJ2 (high-carbon chromium bearing steel), and synthetic resins such as PA66 (polyamide 66) and PPS (polyphenylene sulfide). However, the material and manufacturing method of the valve body 60 are not limited to these.

[0069] As shown in Figure 4, the valve body 60 rotates around a predetermined rotation axis C2. The rotation axis C2 of the valve body 60 passes through the spherical center P of the valve body 60. The rotation axis C2 is set to a fixed position, and the valve body 60 rotates at a fixed position.

[0070] A drive shaft 66 is positioned on the rotation axis C2. The drive shaft 66 constitutes the drive mechanism 40B. The drive shaft 66 is positioned on the rotation axis C2 and one end is connected to the valve body 60. Specifically, as shown in Figure 5, a shaft hole 67 is formed in the valve body 60, and one end of the drive shaft 66 is inserted into this shaft hole 67. Therefore, the portion of the valve body 60 where the shaft hole 67 is formed constitutes a connecting portion to which the drive shaft 66 is connected. The shaft hole 67 is a bottomed hole with a bottom portion 67a. A gap is formed between the inner circumferential surface of the shaft hole 67 and the outer circumferential surface of the drive shaft 66, allowing refrigerant to flow through.

[0071] The other end of the drive shaft 66 protrudes from the outer circumferential surface of the housing 31 of the valve body 40A and is connected to the reduction unit 65 and the drive unit 64 that constitute the drive mechanism 40B. In this embodiment, the drive shaft 66 is arranged in a horizontal direction perpendicular to the central axis C1 of the valve body 40A.

[0072] The drive unit 64 is, for example, an electric motor. The drive unit 64 generates and outputs rotational power. The drive unit 64 employs an electric motor with an adjustable rotation angle, such as a stepping motor. The reduction unit 65 reduces the rotational power of the drive unit 64 and transmits it to the drive shaft 66. The reduction unit 65 is composed of, for example, multiple reduction gears. The drive mechanism 40B is also an operating mechanism that rotates the valve body 60 by rotating the drive shaft 66.

[0073] Figure 5 shows a reference axis C3 perpendicular to the rotation axis C2 of the valve body 60, and a reference axis C4 perpendicular to both the rotation axis C2 and the reference axis C3. The rotation axis C2, the reference axis C3, and the reference axis C4 are perpendicular to each other at the spherical center P of the valve body 60.

[0074] The valve body 60 has a through hole 61 and a recess 62. Both the through hole 61 and the recess 62 constitute passages for the refrigerant. The through hole 61 is a hole that penetrates the valve body 60. In contrast, the recess 62 is formed by recessing the outer surface 60a of the valve body 60.

[0075] The through-hole 61 is formed at two locations on the outer surface 60a of the valve body 60. One opening 61a of the through-hole 61 is formed on the reference axis C3. The other opening 61b is formed on the reference axis C4. Therefore, as shown in Figures 6A and 6B, the through-hole 61 is formed in a roughly L-shaped curve. The areas of both openings 61a and 61b are the same. The cross-sectional area of ​​the through-hole 61 (the area of ​​the cross section perpendicular to the center line of the through-hole 61; the cross-sectional area) is approximately the same as the area of ​​each opening 61a and 61b.

[0076] The recess 62 is formed on the outer surface 60a of the valve body 60 over a range (approximately 90° around the rotation axis C2) that spans from position G1, located on the opposite side of the reference axis C3 with respect to one opening 61a of the through hole 61, to position G2, located on the opposite side of the reference axis C4 with respect to the other opening 61b of the through hole 61.

[0077] The bottom surface 62a of the recess 62 is a single flat surface. This bottom surface 62a is formed across positions G1 and G2. The bottom surface 62a may be composed of multiple flat surfaces or of curved surfaces. The bottom surface 62a of the recess 62 and the openings 61a and 61b of the through hole 61 are positioned at an angle of approximately 45°.

[0078] The valve body 60 is not a perfect sphere because of the through hole 61 and the recess 62, and is a sphere with a portion of its spherical surface (outer surface 60a) missing. In Figures 6A and 6B, the shape of a perfect sphere without any missing portion is shown by the dashed line L.

[0079] (Switching of flow path by valve body 60) In this embodiment, the valve body 60 is switched between a first mode (see Figure 6A) and a second mode (see Figure 6B) by rotating 90° around the rotation axis C2.

[0080] In the first embodiment shown in Figure 6A, port B and port D are connected by a through-hole 61 in the valve body 60, and port A and port C are connected by a recess 62. Therefore, as shown by the solid arrows in Figure 1, the refrigerant discharged from the compressor 15 flows through the refrigerant piping 51a into the refrigerant flow path 51b of the four-way switching valve 18, passes through port A, the recess 62 of the valve body 60, and port C, flows out of the four-way switching valve 18 through the refrigerant flow path 53b, and is supplied to the outdoor heat exchanger 16 through the refrigerant piping 53a. The refrigerant that flows out from the indoor heat exchanger 21 flows through the connecting piping 13 and refrigerant piping 56a into the refrigerant flow path 56b of the four-way switching valve 18, passes through port D, the through-hole 61 of the valve body 60, and port B, flows out of the four-way switching valve 18 through the refrigerant flow path 52b, and is drawn into the compressor 15 through the refrigerant piping 52a. As a result, the air conditioner 10 can perform cooling operation.

[0081] In the second embodiment shown in Figure 6B, port B and port C are connected by a through-hole 61 in the valve body 60, and port A and port D are connected by a recess 62. Therefore, as shown by the dotted arrow in Figure 1, the refrigerant discharged from the compressor 15 flows through the refrigerant piping 51a into the refrigerant flow path 51b of the four-way switching valve 18, passes through port A, the recess 62 of the valve body 60, and port D, flows out of the four-way switching valve 18 through the refrigerant flow path 56b, and is supplied to the indoor heat exchanger 21 through the refrigerant piping 56a and the connecting piping 13. The refrigerant that flows out from the outdoor heat exchanger 16 flows through the refrigerant piping 53a into the refrigerant flow path 53b of the four-way switching valve 18, passes through port C, the through-hole 61 of the valve body 60, and port B, flows out of the four-way switching valve 18 through the refrigerant flow path 52b, and is drawn into the compressor 15 through the refrigerant piping 52a. As a result, the air conditioner 10 can perform heating operation.

[0082] The through-hole 61 of the valve body 60 is always in communication with port B, and by rotating the valve body 60 90° around the rotation axis C2, it selectively communicates with port D and port C. Since port B is connected to the suction pipe 52a and refrigerant flow path 52b of the compressor 15, the through-hole 61, which is always in communication with port B, becomes a passage through which "low-pressure refrigerant" flows.

[0083] The recess 62 is always in communication with port A, and the valve body 60 selectively communicates with port C and port D by rotating 90° around the rotation axis C2. Since port A is connected to the discharge pipe 51a and refrigerant flow path 51b of the compressor 15, the recess 62, which is always in communication with port A, becomes a passage through which "high-pressure refrigerant" flows.

[0084] Furthermore, the refrigerant passages 51b, 53b, and 56b of the flow path section 32 can be called high-pressure refrigerant passages HP (see Figures 11 and 12) because high-pressure refrigerant flows through them, while the refrigerant passages 52b, 53b, and 56b can be called low-pressure refrigerant passages LP (see Figures 11 and 12) because low-pressure refrigerant flows through them. The refrigerant passages 53b and 56b can become either high-pressure or low-pressure refrigerant passages by switching the valve body 60.

[0085] As shown in Figures 6A and 6B, sealing portions 34a, 34b, 34c, and 34d are integrally formed on the inner surface of the valve chamber 31A of the housing 31, around each of the ports A to D. For example, the sealing portions 34a to 34d are integrally formed with the flow path portion 32 when the flow path portion 32 is molded by injection molding or die casting. The sealing portions 34a to 34d are annular protrusions that project from the inner surface of the valve chamber 31A. The tips of these sealing portions 34a to 34d are in contact with the outer surface 60a of the valve body 60. In this embodiment, the sealing portions 34a to 34d are formed in a circular annular shape substantially along the periphery of the cylindrical refrigerant flow paths 51b, 52b, 53b, and 56b. However, the sealing portions 34a to 34d may also be annular in shape such as a rectangular shape.

[0086] Specifically, in the first embodiment shown in Figure 6A, the sealing portion 34b formed around port B on the inner surface of valve chamber 31A is in contact with the area around the opening 61b of the through hole 61 on the outer surface 60a of valve body 60. The sealing portion 34d formed around port D on the inner surface of valve chamber 31A is in contact with the area around the opening 61a of the through hole 61 on the outer surface 60a of valve body 60.

[0087] Therefore, the sealing portions 34b and 34d prevent the low-pressure refrigerant flowing through ports B, D, and the through-hole 61 from leaking into the gap between the outer surface 60a of the valve body 60 and the inner surface of the valve chamber 31A. Furthermore, the sealing portions 34b and 34d prevent the refrigerant flowing through other ports (high-pressure refrigerant) from flowing into ports B, D, and the through-hole 61. This prevents the mixing of low-pressure and high-pressure refrigerants.

[0088] In contrast, the sealing portions 34a and 34c formed around ports A and C on the inner surface of the valve chamber 31A are partially in contact with the area around the recess 62 on the outer surface 60a of the valve body 60, but the other portions are located radially outside the recess 62 and do not come into contact with the outer surface 60a of the valve body 60. As a result, the recess 62 and the valve chamber 31A are in communication, and the high-pressure refrigerant flowing through ports A, C, and the recess 62 leaks into the gap between the outer surface 60a of the valve body 60 and the inner surface of the valve chamber 31A.

[0089] When high-pressure refrigerant leaks into the gap between the outer surface 60a of the valve body 60 and the inner surface of the valve chamber 31A, the pressure of the high-pressure refrigerant is applied to most of the outer surface 60a of the valve body 60, excluding the openings 61a and 61b of the through-hole 61. The pressure of the high-pressure refrigerant is also applied to the recess 62 through which the high-pressure refrigerant passes. As a result, the outer surface 60a of the valve body 60 is strongly pressed against the sealing portions 34b and 34d formed around ports B and D.

[0090] As a result, the sealing portions 34b and 34d can further suppress the leakage of low-pressure refrigerant flowing through ports B, D, and the through-hole 61 into the gap between the outer surface 60a of the valve body 60 and the inner surface of the valve chamber 31A. Furthermore, the sealing portions 34b and 34d can further suppress the flow of high-pressure refrigerant flowing through areas other than ports B, D, and the through-hole 61—in other words, high-pressure refrigerant flowing through ports A, C, and the recess 62, as well as high-pressure refrigerant leaking from these areas—into ports B, D, and the through-hole 61.

[0091] In the second embodiment shown in Figure 6B, the sealing portion 34b formed around port B on the inner surface of valve chamber 31A is in contact with the area around the opening 61a of the through hole 61 on the outer surface 60a of valve body 60. The sealing portion 34c formed around port C on the inner surface of valve chamber 31A is in contact with the area around the opening 61b of the through hole 61 on the outer surface 60a of valve body 60.

[0092] Therefore, the sealing portions 34b and 34c prevent the low-pressure refrigerant flowing through ports B, C, and the through-hole 61 from leaking into the gap between the outer surface 60a of the valve body 60 and the inner surface of the valve chamber 31A. Furthermore, the sealing portions 34b and 34c prevent the refrigerant flowing through areas other than ports B, C, and the through-hole 61 (high-pressure refrigerant) from flowing into ports B, C, and the through-hole 61. This prevents the mixing of low-pressure and high-pressure refrigerants.

[0093] In contrast, the sealing portions 34a and 34d formed around ports A and D on the inner surface of the valve chamber 31A partially contact the area around the recess 62 on the outer surface 60a of the valve body 60, but other portions are located radially outside the recess 62 and do not contact the outer surface 60a of the valve body 60. Therefore, the refrigerant flowing through ports A, D, and the recess 62 leaks into the gap between the outer surface 60a of the valve body 60 and the inner surface of the valve chamber 31A.

[0094] When high-pressure refrigerant leaks into the gap between the outer surface 60a of the valve body 60 and the inner surface of the valve chamber 31A, the pressure of the high-pressure refrigerant is applied to most of the outer surface 60a of the valve body 60, excluding the through-hole 61, and to the recess 62 through which the high-pressure refrigerant passes. As a result, the valve body 60 is strongly pressed against the sealing portions 34b and 34c formed around ports B and C.

[0095] As a result, the sealing portions 34b and 34c can further suppress the leakage of low-pressure refrigerant flowing through ports B, C, and the through-hole 61 into the gap between the outer surface 60a of the valve body 60 and the inner surface of the valve chamber 31A. Furthermore, the sealing portions 34b and 34c can further suppress the flow of high-pressure refrigerant flowing through areas other than ports B, C, and the through-hole 61—in other words, high-pressure refrigerant flowing through ports A, D, and the recess 62, as well as high-pressure refrigerant leaking from these areas—into ports B, C, and the through-hole 61.

[0096] The sealing portions 34a to 34d are formed integrally with the flow channel portion 32. Therefore, the number of parts can be reduced compared to the case where the sealing portions 34a to 34d are formed separately from the flow channel portion 32. In addition, since the flow channel portion 32 is molded from synthetic resin or the like, the sealing portions 34a to 34d can be easily molded integrally.

[0097] Of the four ports A to D, only high-pressure refrigerant flows through port A, so the seal portion 34a formed around port A is not used in practice. Therefore, the seal portion 34a may be omitted.

[0098] As described above, in the four-way diverter valve 18, if high-pressure refrigerant leaks into the gap between the outer surface 60a of the valve body 60 and the inner surface of the valve chamber 31A, the pressure of the high-pressure refrigerant is applied to most of the outer surface 60a of the valve body 60, excluding the through hole 61, and to the recess 62 through which the high-pressure refrigerant passes, causing the valve body 60 to be strongly pressed against the seal portions 34b to 34d formed around ports B to D. Therefore, when switching the valve body 60 of the four-way diverter valve 18 between the first and second positions, it is necessary to rotate the valve body 60 with high torque. The four-way diverter valve 18 of this embodiment is equipped with a pressure equalization mechanism 80 to reduce the rotational torque of the valve body 60.

[0099] Figure 7 is a front view of the valve body. Figure 8 is a view taken along arrow F in Figure 7. Figure 9 is a front view showing the end face of the drive shaft on the valve body side. Figure 10 is a view taken along arrow G in Figure 9. The pressure equalization mechanism 80 of this embodiment has a pressure equalization passage 81 formed in the valve body 60, as shown in Figures 6A, 6B, 7, and 8. The pressure equalization passage 81 connects the through hole (first passage) 61 of the valve body 60 to the valve chamber 31A. Specifically, the pressure equalization passage 81 is formed to penetrate the bottom 67a of the shaft hole 67 into which the drive shaft 66 is inserted, and connects the shaft hole 67 and the through hole 61. The pressure equalization passage 81 is formed along the rotation axis C2 of the valve body 60. The pressure equalization passage 81 is closed by the end face 66a of the drive shaft 66 inserted into the shaft hole 67.

[0100] As shown in Figures 7 to 10, the pressure equalization mechanism 80 has an opening / closing mechanism 82 that opens and closes the pressure equalization passage 81. The opening / closing mechanism 82 opens and closes the pressure equalization passage 81 by moving the drive shaft 66 in the axial direction.

[0101] Figure 11 is a schematic diagram of a flow path switching valve showing the state in which the pressure equalization mechanism is not in operation. Figure 12 is a schematic diagram of a flow path switching valve showing the state in which the pressure equalization mechanism is in operation. As shown in Figure 11, when the valve body 60 is in the first or second position and cooling or heating operation is being performed, the pressure equalization flow path 81 constituting the pressure equalization mechanism 80 is closed by the end face 66a of the drive shaft 66. Therefore, the through hole (first passage) 61 of the valve body 60 through which the low-pressure refrigerant flows, the recess (second passage) 62 of the valve body 60 through which the high-pressure refrigerant flows, and the gap between the inner surface of the valve chamber 31A where the high-pressure refrigerant is present and the outer surface 60a of the valve body 60 are separated by the seal portion 34 (corresponding to the seal portions 34b to 34d in Figures 6A and 6B), thereby suppressing the mixing of the low-pressure refrigerant and the high-pressure refrigerant.

[0102] When the valve body 60 is rotated between a first and second position to switch between cooling and heating operation, the opening / closing mechanism 82 moves the drive shaft 66 axially so that the end face of the drive shaft 66 moves away from the bottom 67a of the shaft hole 67, as shown in Figure 12, and opens the pressure equalization passage 81. Since a gap is formed between the outer surface of the drive shaft 66 and the inner surface of the shaft hole 67 through which refrigerant can flow, the pressure equalization passage 81 connects the inside of the valve chamber 31A and the through hole 61. As a result, the high-pressure refrigerant that was present between the inner surface of the valve chamber 31A and the outer surface 60a of the valve body 60 enters the through hole 61 via the pressure equalization passage 81, mixing the high-pressure refrigerant and the low-pressure refrigerant and balancing their pressures. This reduces the rotational torque required to rotate the valve body 60 between the first and second positions.

[0103] In the examples shown in Figures 11 and 12, a disc-shaped flange 66b projecting radially is formed on the end of the drive shaft 66 inserted into the shaft hole 67. This flange increases the contact area between the end face 66a of the drive shaft 66 and the bottom 67a of the shaft hole 67. Furthermore, the pressure of the high-pressure refrigerant applied to the flange 66b ensures that the pressure equalization passage 81 is reliably closed by the end face 66a of the drive shaft 66. The flange 66b may also have a hole that penetrates it axially, and if the hole in the flange 66b is opened when the end face 66a of the drive shaft 66 opens the pressure equalization passage 81, mixing of the high-pressure refrigerant and the low-pressure refrigerant can be promoted.

[0104] The opening / closing mechanism 82 prevents the valve body 60 from rotating until it opens the pressure equalization passage 81. The specific structure of the opening / closing mechanism 82 that achieves such an action will be described below. As shown in Figures 9 and 10, the opening / closing mechanism 82 has a recess 85 formed on the outer circumferential surface of the drive shaft 66. This recess 85 is formed in a predetermined range in the circumferential direction of the drive shaft 66. The recess 85 is open at the end face 66a of the drive shaft 66 and the outer circumferential surface of the drive shaft 66. Cam surfaces 85b and 85c are formed inside the recess 85. The cam surfaces 85b and 85c face the bottom 67a of the shaft hole 67.

[0105] The cam surfaces 85b and 85c have varying axial positions in the circumferential direction of the drive shaft 66. Specifically, the cam surfaces 85b and 85c include a cam surface 85b that inclins away from the end face 66a as it moves toward one side of the circumferential direction of the drive shaft 66 (for example, the right side in Figure 10), and a cam surface 85c that inclins toward the end face 66a. These cam surfaces 85b and 85c are arranged alternately in the circumferential direction of the drive shaft 66. As a result, two V-shaped small recesses 85a are formed by adjacent cam surfaces 85b and 85c, and one intermediate protrusion 85d is formed between these two small recesses 85a.

[0106] As shown in Figures 7 and 8, the opening / closing mechanism 82 has a protrusion 83 formed in the shaft hole 67 of the valve body 60. The protrusion 83 projects radially inward from the inner circumferential surface of the shaft hole 67. One end of the protrusion 83 in the axial direction of the drive shaft 66 is connected to the bottom 67a of the shaft hole 67. The other end (tip) of the protrusion 83 is formed in a V-shape and has two inclined surfaces 83b and 83c that are inclined in opposite directions. One of the two inclined surfaces 83b is a surface that is substantially parallel to one cam surface 85b of the recess 85 in Figure 10, and the other cam surface 83c is a surface that is substantially parallel to the other cam surface 85c of the recess 85. The protrusion 83 functions as a cam receiving portion that contacts the cam surfaces 85b and 85c and moves relatively along the cam surfaces 85b and 85c.

[0107] Figure 13A is an explanatory diagram showing the operation flow of the flow path switching valve. The flow path switching valve 18 operates in the order of (a) to (c) in Figure 13A (or in the reverse order). The circumferential width of the protrusion 83 formed in the shaft hole 67 of the valve body 60 is smaller than the circumferential width of the recess 85 of the drive shaft 66. When the valve body 60 is in the first or second position and is performing cooling or heating operation, the protrusion 83 is positioned within one of the small recesses 85a.

[0108] As shown in Figures 13A(a) to (c), when the drive shaft 66 is rotated in the direction of arrow b by the drive unit 64 of the drive mechanism 40B, the recess 85 formed on the drive shaft 66 moves in the same direction b. As a result, the protrusion 83 of the shaft hole 67 moves relative to the recess 85 in the opposite direction to arrow b. During this time, the drive shaft 66 rotates freely relative to the valve body 60 and does not rotate the valve body 60. Also, during this time, as shown in Figure 13A(b), as the protrusion 83 of the shaft hole 67 passes through the intermediate protrusion 85d, the drive shaft 66 moves axially along the cam surfaces 85b and 85c. As a result, the end face 66a of the drive shaft 66 moves away from the pressure equalization passage 81, and the pressure equalization passage 81 is opened.

[0109] As described above, the cam surfaces 85b, 85c and the protrusion (cam receiving portion) 83 constitute a conversion unit that converts the rotation of the drive shaft 66 by the drive unit 64 into movement of the drive shaft 66 in the axial direction. The cam surfaces described above may be provided on the shaft hole 67 side, and the cam receiving portion may be provided on the drive shaft 66 side.

[0110] Figure 13B is a flowchart showing the control procedure of the control unit related to switching operations. The operation procedure of the four-way switching valve 18, including control by the control unit 20, will be described below. When the control unit 20 receives an instruction to switch operations, for example, an instruction to switch between cooling operation and heating operation, an instruction to switch between heating operation and defrost operation, or an instruction to switch between heating operation and its shutdown (step S1), it activates the drive unit 64 (see Figure 4) of the four-way switching valve 18 and rotates the drive shaft 66 to rotate the valve body 60 and reverse the flow of refrigerant in the refrigerant circuit 30 (step S2). At this time, for example, by rotating the drive shaft 66 by 45°, the state changes from state (a) to state (b) in Figure 13A. As a result, the pressure equalization passage 81 is opened and the refrigerant in the valve chamber 31A is equalized (step S3). In this state, the drive unit 64 is temporarily stopped.

[0111] The control unit 20 determines whether a predetermined time has elapsed (step S4). This predetermined time is the time required to sufficiently equalize the pressure of the refrigerant in the valve chamber 31A to the extent that the valve body 60 can be rotated. Once the predetermined time has elapsed, the control unit 20 operates the drive unit 64 again and rotates the drive shaft 66 by another 45°, thereby transitioning from state (b) to state (c) in Figure 13A (step S5). Subsequently, the control unit 20 rotates the drive shaft 66 by another 90° to switch the valve body 60 between the first and second positions (step S6). In state (c) in Figure 13A, the pressure equalization passage 81 is closed again, but at that point, the refrigerant in the valve chamber 31A is sufficiently equalized, so the valve body 60 can be rotated with low torque. Furthermore, once the valve body 60 rotates, the through-hole 61 of the valve body 60 communicates with the valve chamber 31A even without using the pressure equalization passage 81 (the seal by the seal portion 34 is released), so the valve body 60 can be rotated with low torque.

[0112] Based on the above, after receiving an instruction to switch operations in step S1, the control unit 20 rotates the valve body 60 in step S6, after going through steps S2 to S5. Therefore, when the control unit 20 receives an instruction to switch operations, it also receives a signal to rotate the valve body 60.

[0113] Figure 13C is a flowchart showing the control procedure of the control unit related to switching operations in a modified example. In the embodiment shown in Figure 13B, the drive unit 64 was temporarily stopped when performing the equalization operation. In contrast, the modified example shown in Figure 13C is an example in which the drive unit 64 is operated continuously without stopping.

[0114] In this modified example, when the control unit 20 receives an instruction to switch operation (step S11), it activates the drive unit 64 to rotate the drive shaft 66 at a low speed (step S12). This opens the pressure equalization passage 81 and equalizes the pressure of the refrigerant in the valve chamber 31A (step S13). Subsequently, the control unit 20 determines whether the drive shaft 66 has rotated by a predetermined angle (step S14). This predetermined angle is the angle from when the drive shaft 66 starts rotating and opens the pressure equalization passage 81 until it closes, and is the rotation angle from state (a) to state (c) in Figure 13A (for example, 90°).

[0115] When the drive shaft 66 rotates by a predetermined angle, the control unit 20 increases the rotational speed of the drive shaft 66 (step S15) and rotates the valve body 60 to switch the position of the valve body 60 between a first position and a second position (step S16). In this modified example, during the pressure equalization operation, the drive shaft 66 is rotated at a low speed to ensure sufficient time for pressure equalization, and once pressure equalization is complete, the drive shaft 66 is rotated at high speed to quickly switch the position of the valve body 60, allowing for a smooth transition from pressure equalization to the rotation of the valve body 60.

[0116] [Second Embodiment] Figure 14 is a perspective view showing the valve body and drive shaft in the second embodiment. Figure 15 is a front view of the valve body and drive shaft. The pressure equalization mechanism 80 of the second embodiment has a pressure equalization passage 81 and an opening / closing mechanism 82. However, the pressure equalization mechanism 80 of the second embodiment differs from that of the first embodiment mainly in the configuration of the opening / closing mechanism 82.

[0117] As shown in Figure 15, the pressure equalization passage 81 is formed in the bottom 67a of the shaft hole 67, similar to the first embodiment, and connects the shaft hole 67 and the through hole 61. The pressure equalization passage 81 is positioned radially offset from the rotation axis C2 of the valve body 60. The pressure equalization passage 81 is closed by the end face 66a of the drive shaft 66 (see Figure 16).

[0118] The opening and closing mechanism 82 of this embodiment opens and closes the pressure equalization passage 81 during the process of rotating the drive shaft 66, rather than moving the drive shaft 66 in the axial direction as in the first embodiment. Specifically, as shown in Figures 14 and 15, the opening and closing mechanism 82 includes a communication passage 66c formed in the drive shaft 66. The communication passage 66c is a recessed groove that is partially formed in the circumferential direction of the drive shaft 66 and is formed over the entire length of the drive shaft 66.

[0119] The drive shaft 66 has a communication passage 66c and is formed in a shape in which a part of its circumferential direction is missing. Specifically, the drive shaft 66 is formed in a shape in which half of its circumferential direction is missing. Therefore, the drive shaft 66 has a semicircular cross-section and a substantially flat side surface 66d.

[0120] The opening / closing mechanism 82 includes a rotation restricting portion 67c formed in the shaft hole 67 of the valve body 60. The rotation restricting portion 67c is a projection that protrudes radially inward from the inner circumference of the shaft hole 67. The rotation restricting portion 67c occupies (fills) a part of the circumferential direction of the shaft hole 67. For example, as shown in Figure 15, the rotation restricting portion 67c occupies a range in the shaft hole 67 where the central angle is approximately 60° around the rotation axis C2. Therefore, the shaft hole 67 is formed in a range where the central angle is substantially approximately 300°, and the drive shaft 66 is inserted in a range of 180° of that range. Therefore, a gap S with a central angle θ of approximately 120° is formed inside the shaft hole 67. The drive shaft 66 rotates freely within this gap S, preventing the valve body 60 from rotating. When the drive shaft 66 is rotated within the gap S and the communication passage 66c is aligned with the pressure equalization passage 81, the pressure equalization passage 81 is opened.

[0121] Figure 16 is a schematic diagram of a flow path switching valve showing the state in which the pressure equalization mechanism is not in operation. Figure 17 is a schematic diagram of a flow path switching valve showing the state in which the pressure equalization mechanism is in operation. As shown in Figure 16, when the valve body 60 is in the first or second position and cooling or heating operation is being performed, the pressure equalization flow path 81 constituting the pressure equalization mechanism 80 is closed by the end face 66a of the drive shaft 66. Therefore, the through hole (first passage) 61 of the valve body 60 through which the low-pressure refrigerant flows, the recess (second passage) 62 of the valve body 60 through which the high-pressure refrigerant flows, and the gap between the outer surface 60a of the valve body 60 where the high-pressure refrigerant is present and the inner surface of the valve chamber 31A are partitioned by the seal portion 34, and mixing of the low-pressure refrigerant and the high-pressure refrigerant is suppressed.

[0122] When the valve body 60 is rotated between a first and second position to switch the operation of the air conditioner 10, the opening / closing mechanism 82 rotates the drive shaft 66 so that the communication passage 66c of the drive shaft 66 aligns with the pressure equalization passage 81 of the shaft hole 67, thereby opening the pressure equalization passage 81. As a result, the pressure equalization passage 81 connects the inside of the valve chamber 31A to the through hole 61. The high-pressure refrigerant that was present in the gap between the inner surface of the valve chamber 31A and the outer surface 60a of the valve body 60 enters the through hole 61 via the pressure equalization passage 81, mixing the high-pressure refrigerant and low-pressure refrigerant and balancing their pressures. This reduces the rotational torque required to rotate the valve body 60 between the first and second positions. However, the opening / closing mechanism 82 rotates the drive shaft 66 but does not rotate the valve body 60 until the pressure equalization passage 81 is opened.

[0123] Figures 18A and 18B are explanatory diagrams showing the operation flow of the flow path switching valve. The flow path switching valve 18 operates in the order of (a) and (b) in Figure 18A, and (b) and (c) in Figure 18B (or in the reverse order). First, when cooling or heating operation is performed, as shown in Figure 18A(a), the side surface 66d of the drive shaft 66 abuts against one side surface of the rotation restricting part 67c, and the end surface 66a of the drive shaft 66 closes the pressure equalizing flow path 81. When switching from cooling operation to heating operation, the control unit 20 activates the drive unit 64 (see Figure 4) of the drive mechanism 40B and rotates the drive shaft 66. At this time, for example, by rotating the drive shaft 66 by 60°, the state transitions from state (a) to state (b) in Figure 18A. As a result, the connecting passage 66c coincides with the pressure equalization passage 81, the pressure equalization passage 81 is opened through the connecting passage 66c, and the refrigerant in the valve chamber 31A is equalized in pressure.

[0124] The control unit 20 temporarily stops the drive unit 64 until a predetermined time has elapsed in this state. Then, the control unit 20 rotates the drive shaft 66 by 60° to transition from state 18A(b) to state 18B(c), and closes the equalizing flow path 81 again with the end face 66a of the drive shaft 66. Then, as shown in Figure 18B(d), the valve body 60 is switched between the first and second positions by rotating the drive shaft 66 by another 90°.

[0125] In the state shown in Figure 18B(c), the pressure equalization passage 81 is closed again, but at that point, the refrigerant in the valve chamber 31A is almost at equal pressure. Therefore, the rotational torque of the drive shaft 66 remains reduced, and the drive shaft 66 can be rotated with even lower torque. Also, once the valve body 60 has rotated, the through-hole 61 of the valve body 60 communicates with the valve chamber 31A without using the pressure equalization passage 81, so the valve body 60 can be rotated with low torque.

[0126] In the second embodiment, the communication passage 66c formed in the drive shaft 66 extends along the entire length of the drive shaft 66, but it is sufficient if it is formed only in a range that allows the equalizing flow path 81 to be opened and connect the valve chamber 31A with the through hole 61 (for example, a range located within the valve chamber 31A).

[0127] [Third Embodiment] Figures 19A and 20A are schematic explanatory diagrams of a flow path switching valve showing the state of the pressure equalization mechanism in the third embodiment, and Figures 19B and 20B are plan views showing the positional relationship between the pressure equalization flow path and the closing member in the state shown in Figures 19A and 20A, respectively. In particular, Figures 19A to 20B all show the valve body 60 in the first or second position. Figures 21 and 22 are perspective views of the valve body and drive shaft, respectively.

[0128] The pressure equalization mechanism 80 of this embodiment differs from the second embodiment in the configuration of the opening / closing mechanism 82. As shown in Figure 21, the pressure equalization passage 81 is formed in the bottom 67a of the shaft hole 67, similar to the second embodiment, and connects the shaft hole 67 and the through hole 61. The pressure equalization passage 81 is positioned radially offset from the rotation axis C2 of the valve body 60.

[0129] The opening / closing mechanism 82 of this embodiment has a closing member 87 that closes the pressure equalization passage 81. The closing member 87 of this embodiment is spherical. The closing member 87 is located inside the shaft hole 67 of the valve body 60. The closing member 87 has an outer diameter larger than the inner diameter of the pressure equalization passage 81. The closing member 87 closes the pressure equalization passage 81 by covering the upper end of the pressure equalization passage 81.

[0130] As shown in Figure 22, the opening / closing mechanism 82 has an opening / closing operating section 88 formed on the drive shaft 66. The drive shaft 66 is formed in a cylindrical shape. The opening / closing operating section 88 is provided at one end of the drive shaft 66 in the axial direction and is inserted into the shaft hole 67 (see Figure 21). The opening / closing operating section 88 is formed in a semicircular cylindrical shape with half of the circumferential direction of the drive shaft 66 missing. Therefore, the opening / closing operating section 88 has an arc-shaped outer surface 88a and a flat side surface 88b.

[0131] A receiving recess 88c is formed in the opening / closing operation section 88. The closing member 87 is housed in the receiving recess 88c (see Figure 21). The receiving recess 88c is formed by cutting out a portion of the outer circumferential surface of the opening / closing operation section 88 in a roughly triangular shape toward the rotation axis C2 of the drive shaft 66.

[0132] As shown in Figure 21, the opening / closing mechanism 82, similar to the second embodiment, includes a rotation restricting portion 67c formed in the shaft hole 67 of the valve body 60. The rotation restricting portion 67c is a projection that protrudes radially inward from the inner circumference of the shaft hole 67. The rotation restricting portion 67c occupies (fills) a part of the circumferential direction of the shaft hole 67. For example, the rotation restricting portion 67c occupies a range of approximately 60° in the shaft hole 67, with a central angle centered on the rotation axis C2. Therefore, the shaft hole 67 is formed with a range of approximately 300° in terms of central angle, and the opening / closing operation portion 88 of the drive shaft 66 is inserted into a range of 180°. As a result, a gap S with a central angle θ of approximately 120° (see Figures 19B and 20B) is formed inside the shaft hole 67. The drive shaft 66 rotates freely within this gap S, preventing the valve body 60 from rotating.

[0133] When the drive shaft 66 is rotated within the range of the gap S and the pressure equalization passage 81 is positioned within the housing recess 88c, as shown in Figures 19A and 19B, the closing member 87 is drawn to the pressure equalization passage 81 by the pressure difference between the valve chamber 31A and the through hole 61, covering the upper end of the pressure equalization passage 81. As a result, the closing member 87 closes the pressure equalization passage 81.

[0134] When the drive shaft 66 is rotated within the range of the gap S, and the pressure equalization passage 81 is positioned outside the housing recess 88c as shown in Figures 20A and 20B, the closing member 87 detaches from the pressure equalization passage 81. The end face of the opening / closing operation part 88 is positioned to lightly contact the upper end of the pressure equalization passage 81 (the bottom 67a of the shaft hole 67) or with a small gap between them. Therefore, the pressure equalization passage 81 is not blocked by the opening / closing operation part 88 and remains open.

[0135] As shown in Figures 19A and 19B, when the valve body 60 is in the first or second position and cooling or heating operation is being performed, the pressure equalization passage 81 constituting the pressure equalization mechanism 80 is closed by the closing member 87. As a result, the through-hole (first passage) 61 of the valve body 60 through which the low-pressure refrigerant flows, the recess (second passage) 62 of the valve body 60 through which the high-pressure refrigerant flows, and the gap between the outer surface 60a of the valve body 60 where the high-pressure refrigerant is present and the inner surface of the valve chamber 31A are separated by the seal portion 34, thereby suppressing the mixing of the low-pressure refrigerant and the high-pressure refrigerant.

[0136] When the valve body 60 is rotated between a first position and a second position to switch the operation of the air conditioner 10, the opening / closing mechanism 82 rotates the drive shaft 66 so that the housing recess 88c of the opening / closing operation part 88 is offset from the pressure equalization passage 81, as shown in Figures 20A and 20B. Since the closing member 87 is positioned in the housing recess 88c, it moves away from the pressure equalization passage 81 as the drive shaft 66 rotates. As a result, the pressure equalization passage 81 is opened, connecting the inside of the valve chamber 31A to the through hole 61.

[0137] Therefore, the high-pressure refrigerant present in the gap between the inner surface of the valve chamber 31A and the outer surface 60a of the valve body 60 enters the through-hole 61 via the pressure equalization passage 81, mixing the high-pressure refrigerant and the low-pressure refrigerant and balancing their pressures. This reduces the rotational torque required to rotate the valve body 60 between the first and second positions. However, the opening / closing mechanism 82 rotates the drive shaft 66 but does not rotate the valve body 60 until the pressure equalization passage 81 is opened.

[0138] Figures 23A and 23B are explanatory diagrams showing the operation flow of the flow path switching valve. The flow path switching valve 18 operates in the order of (a) and (b) in Figure 23A, and (c) and (d) in Figure 23B (or in the reverse order). The operation of pressure equalization will be explained with reference to Figures 23A and 23B. First, when the valve body 60 is in the first or second position and cooling or heating operation is being performed, as shown in Figure 23A(a), the housing recess 88c in the opening / closing operation part 88 of the drive shaft 66 is positioned in the pressure equalization flow path 81, and the closing member 87 closes the pressure equalization flow path 81. This state is the same as that shown in Figures 19A and 19B.

[0139] When switching from cooling operation to heating operation, the control unit 20 stops the compressor 15 and activates the drive unit 64 of the drive mechanism 40B (see Figure 4), rotating the drive shaft 66 by 60° (see arrow c1 in Figure 23A(b)). This transitions the system from state 23A(a) to state 23A(b). This state is the same as that shown in Figures 20A and 20B.

[0140] At this time, the receiving recess 88c shifts away from the pressure equalization passage 81, and the closing member 87 inside the receiving recess 88c detaches from the pressure equalization passage 81. As a result, the pressure equalization passage 81 is opened, and the refrigerant in the valve chamber 31A is equalized in pressure. The rotation of the drive shaft 66 at this time is rotation within the gap S shown in Figures 19B and 20B, and does not rotate the valve body 60.

[0141] The control unit 20 stops the drive unit 64 while the pressure is equalized and waits until a predetermined time has elapsed (until the pressure equalization is complete). Then, the control unit 20 rotates the drive shaft 66 by 90° (see arrow c2 in Figure 23B(c)) to transition from state 23A(b) to state 23B(c). This rotation of the drive shaft 66 causes the side surface 88b of the opening / closing operation unit 88 to push the side surface of the rotation restricting unit 67c, as shown in Figure 20B, to rotate the valve body 60 and switch the valve body 60 between the first and second positions. At this time, the pressure equalization passage 81 is open and the refrigerant in the valve chamber 31A is pressurized, so the rotational torque of the drive shaft 66 is reduced and the valve body 60 can be rotated with low torque.

[0142] After switching the valve body 60 between the first and second positions, the control unit 20 rotates the drive shaft 66 in the reverse direction by 60° (see arrow c3 in Figure 23B(d)), transitioning from state 23B(c) to state 23B(d). This positions the pressure equalization passage 81 within the housing recess 88c of the opening / closing operation unit 88. The closing member 87 within the housing recess 88c is then drawn towards the pressure equalization passage 81 by the pressure difference between the valve chamber 31A and the passage 61, which is created by operating the compressor 15 again, thereby closing the pressure equalization passage 81.

[0143] Figure 24 is a flowchart showing the control procedure of the control unit related to switching operations in the third embodiment. When the control unit 20 receives an instruction to switch operations, for example, an instruction to switch between cooling operation and heating operation, an instruction to switch between heating operation and defrost operation, or an instruction to switch between heating operation and its stop (step S21), it stops the compressor 15 (step S22). Next, it operates the drive unit 64 of the four-way switching valve 18 (see Figure 4) and rotates the drive shaft 66 (step S23). At this time, by rotating the drive shaft 66 by 60°, the state changes from state (a) to state (b) in Figure 23A. As a result, the pressure equalization passage 81 is opened and the refrigerant in the valve chamber 31A is equalized (step S24). In this state, the drive unit 64 is stopped.

[0144] The control unit 20 determines whether a predetermined time has elapsed (step S25). This predetermined time is the time required to sufficiently equalize the pressure of the refrigerant in the valve chamber 31A to the extent that the valve body 60 can be rotated. Since the pressure equalization passage 81 is a small hole formed in the axial hole 67 of the valve body 60, it takes a considerable amount of time to equalize the pressure, but care has been taken to complete the pressure equalization in the shortest possible time by stopping the compressor 15.

[0145] After a predetermined time has elapsed, the control unit 20 operates the drive unit 64 again and rotates the drive shaft 66 another 90°, thereby transitioning from state 23A(b) to state 23B(c) (step S26). This switches the valve body 60 between the first and second positions. In state 23A(b), the refrigerant in the valve chamber 31A is sufficiently pressure-equalized, so the valve body 60 can be rotated with low torque.

[0146] Subsequently, the control unit 20 rotates the drive shaft 66 60° in the reverse direction. This positions the pressure equalization passage 81 within the housing recess 88c of the opening / closing operation unit 88. This completes the switching operation of the valve body 60. When the compressor 15 is then activated to start cooling or heating operation, a pressure difference is generated between the valve chamber 31A and the through hole 61, and the closing member 87 in the housing recess 88c is drawn towards the pressure equalization passage 81, closing the pressure equalization passage 81. This makes it possible to perform cooling or heating operation.

[0147] Furthermore, when switching between cooling and heating operation, the drive shaft 66 should be rotated in the opposite direction to the rotation direction of the drive shaft 66 described above.

[0148] In the third embodiment, the receiving recess 88c of the opening / closing operation unit 88 only needs to be able to accommodate the closing member 87 and move the closing member 87 by the rotation of the drive shaft 66 to open and close the pressure equalization passage 81, and its specific arrangement and shape can be changed as appropriate. For example, the receiving recess 88c may be formed on the end face (bottom surface) of the opening / closing operation unit 88 and may have a depth that allows the closing member 87 to move in the axial direction of the drive shaft 66 in conjunction with the opening and closing of the pressure equalization passage 81. In the third embodiment, the angle at which the drive shaft 66 is rotated for the pressure equalization operation can also be changed as appropriate.

[0149] In the third embodiment, the shape of the closing member 87 is not limited to a sphere and can be changed as appropriate. For example, the closing member 87 may be formed in a cylindrical shape, with only the end portion that closes the upper end of the pressure equalization channel 81 being formed in a spherical or conical shape.

[0150] [Other Embodiments] In the above embodiment, when the flow path switching valve 18 equalizes the refrigerant pressure using the pressure equalization mechanism 80, the drive unit 64 is stopped for a predetermined time (steps S3 and S4 in Figure 13B, step S24 in Figure 24), or the speed of the drive unit 64 (rotational speed of the drive shaft 66) is varied (steps S12 to S15 in Figure 13C). However, if the refrigerant pressure is sufficiently equalized, the pressure equalization operation and the rotation of the valve body may be performed continuously at a constant speed without stopping the drive unit 64. Also, in the first and second embodiments, when the refrigerant pressure is equalized using the pressure equalization mechanism 80, the compressor 15 may be stopped, similar to the third embodiment.

[0151] The flow path switching valve 18 in the above embodiment was equipped with a valve body 40A having a cylindrical outer shape, but is not limited thereto. For example, the valve body 40A may be formed in a substantially rectangular parallelepiped shape.

[0152] In the above embodiment, the sealing portions 34a to 34d were formed on the inner surface of the valve chamber 31A in the flow path portion 32, but they may also be integrally formed around the openings 61a and 61b of the through hole (passage) 61 in the valve body 60. In this case, the tips of the sealing portions 34a to 34d come into contact with the inner surface of the valve chamber 31A, thereby suppressing the leakage of refrigerant into the gap between them.

[0153] In the above embodiment, the valve body 60 has a through hole 61 that constitutes a passage for low-pressure refrigerant and a recess 62 that constitutes a passage for high-pressure refrigerant. However, it is not limited to this. For example, the valve body 60 may have a recess formed as a passage for low-pressure refrigerant, or a through hole formed as a passage for high-pressure refrigerant. The valve body 60 is not limited to the spherical shape described above, but may also have other shapes such as a cylindrical shape.

[0154] In the above embodiment, the rotation axis C2 of the valve body 60 was oriented horizontally, but it may be oriented vertically. The rotation axis C2 of the valve body 60 may be oriented in a direction inclined with respect to both the vertical and horizontal directions.

[0155] In the above embodiment, the flow path switching valve 18 was used as a four-way switching valve, but it may also be used as a three-way switching valve.

[0156] [Effects of the Embodiments] (1) The flow path switching valve (four-way switching valve) 18 of each of the above embodiments comprises a housing 31 having a valve chamber 31A inside, and a valve body 60 that is rotatably housed in the valve chamber 31A and can be switched between a first position and a second position by rotational operation. The housing 31 has a first refrigerant flow path (e.g., refrigerant flow path 52b), a second refrigerant flow path (e.g., refrigerant flow path 56b), and a third refrigerant flow path (e.g., refrigerant flow path 53b) that connect the valve chamber 31A and the outside of the housing 31, and the valve body 60 connects the first refrigerant flow path 52b and the second refrigerant flow path 56b in the first position, and connects the first refrigerant flow path 52b and the third refrigerant flow path 53b in the second position, and has a first passage (through hole) 61 inside through which refrigerant at a first pressure flows. Furthermore, the valve body 60 communicates with the third refrigerant flow path 53b in the first position and with the second refrigerant flow path 56b in the second position, and has a second passage (recess) 62 through which refrigerant at a second pressure higher than the first pressure flows. The valve chamber 31A and the second passage 62 communicate with each other when the valve body 60 is in the first or second position. The flow path switching valve 18 is switchable between a configuration that connects the first passage 61 and the valve chamber 31A and a configuration that disconnects said connection, and includes a pressure equalization mechanism 80 that can connect the first passage 61 and the valve chamber 31A when the valve body 60 is in the first or second position.

[0157] With this configuration, the pressure equalization mechanism 80 connects the first passage 61 and the valve chamber 31A, allowing the high-pressure (second pressure) refrigerant and the low-pressure (first pressure) refrigerant to be mixed and the pressure equalized within the flow path switching valve 18. As a result, the torque required to rotate the valve body 60 can be reduced, enabling miniaturization of the drive unit 64 (motor), the reduction unit 65, and so on. In particular, the pressure equalization mechanism 80 can equalize the refrigerant pressure when the valve body 60 is in the first or second position, so it is not necessary to rotate the valve body 60 to equalize the refrigerant pressure. The valve body 60 can be rotated only after the pressure equalization is complete and the rotational torque has been sufficiently reduced.

[0158] (2) In each of the above embodiments, a fourth refrigerant flow path (for example, a refrigerant flow path 51b) is formed in the housing 31, which connects the valve chamber 31A to the outside of the housing 31, and the second passage 62 connects the third refrigerant flow path 53b and the fourth refrigerant flow path 51b in the first position, and connects the second refrigerant flow path 56b and the fourth refrigerant flow path 51b in the second position. With this configuration, high-pressure refrigerant can be flowed using the second passage 62, and the flow path switching valve 18 can be used as a four-way switching valve.

[0159] (3) In each of the above embodiments, the pressure equalization mechanism 80 includes a pressure equalization passage 81 that connects the first passage 61 and the valve chamber 31A, and an opening / closing mechanism 82 that opens and closes the pressure equalization passage 81. With this configuration, high-pressure refrigerant and low-pressure refrigerant can be mixed through the pressure equalization passage 81.

[0160] (4) In each of the above embodiments, the valve body 60 is provided with an operating mechanism (drive mechanism) 40B for rotating the valve body 60, the operating mechanism 40B includes a drive shaft 66 positioned on the rotation axis C2 of the valve body 60, the valve body 60 has a connecting portion 67 to which the drive shaft 66 is connected and to which a pressure equalization passage 81 is formed, and the opening / closing mechanism 82 opens and closes the pressure equalization passage 81 by moving the drive shaft 66.

[0161] With this configuration, the opening and closing mechanism 82 can be configured using the drive shaft 66 that constitutes the operating mechanism 40B.

[0162] (5) In each of the above embodiments, the operating mechanism 40B includes a drive unit 64 that rotates the drive shaft 66 for the rotational operation of the valve body 60, and the opening / closing mechanism 82 opens and closes the pressure equalization passage 81 by utilizing the rotation of the drive shaft 66 by the drive unit 64. With this configuration, the opening / closing mechanism 82 can be constructed using the drive shaft 66 and drive unit 64 that constitute the operating mechanism 40B. Therefore, a drive unit dedicated to the opening / closing mechanism 82 can be omitted.

[0163] (6) In the first embodiment described above, the opening and closing mechanism 82 has conversion units 85b, 85c, and 83 that convert the rotation of the drive shaft 66 by the drive unit 64 into movement of the drive shaft 66 in the axial direction, and the pressure equalization passage 81 is opened and closed by moving the drive shaft 66 in the axial direction using the conversion units. With this configuration, the rotation of the drive shaft 66 by the drive unit 64 is used to move the drive shaft 66 in the axial direction and open and close the pressure equalization passage 81.

[0164] (7) In the first embodiment described above, the conversion unit has cam surfaces 85b and 85c provided on one of the connecting unit 67 and the drive shaft 66, which are displaced axially according to their position around the drive shaft 66, and a cam receiving unit (protrusion) 83 provided on the other of the connecting unit 67 and the drive shaft 66 that contacts the cam surfaces 85b and 85c. With this configuration, by rotating the drive shaft 66, the drive shaft 66 can be moved axially along the cam surfaces 85b and 85c, thereby opening and closing the pressure equalization passage 81.

[0165] (8) In each of the above embodiments, the drive shaft 66 has an axial end face 66a that closes the pressure equalization passage 81. With this configuration, the pressure equalization passage 81 can be easily opened and closed by the axial movement of the drive shaft 66.

[0166] (9) In the second embodiment described above, a communication passage 66c communicating with the valve chamber 31A is formed in a part of the circumferential direction of the drive shaft 66, and the opening / closing mechanism 82 rotates the drive shaft 66 by the drive unit 64 to a rotation position that connects the communication passage 66c to the pressure equalizing passage 81 and to a rotation position that disconnects the communication. With this configuration, the pressure equalizing passage 81 can be opened and closed by rotating the drive shaft 66.

[0167] (10) In the third embodiment described above, the opening / closing mechanism 82 includes a closing member 87 that closes the pressure equalization passage 81 and moves by the rotation of the drive shaft 66. Furthermore, the opening / closing mechanism 82 rotates the drive shaft 66 by the drive unit 64 to a rotation position in which the pressure equalization passage 81 is closed by the closing member 87 and to a rotation position in which the closure is released. With this configuration, the pressure equalization passage 81 can be opened and closed by rotating the drive shaft 66.

[0168] In the third embodiment, by providing a dedicated closing member 87 (separate from the drive shaft 66) for closing the pressure equalization passage 81, the closing member 87 can be formed in a shape suitable for closing the pressure equalization passage 81 (for example, spherical), thereby improving the machinability of the drive shaft 66 and the like.

[0169] (11) In each of the above embodiments, the refrigeration device 10 includes a control unit 20 that controls the pressure equalization mechanism 80 (opening / closing mechanism 82), and when the control unit 20 receives a signal to rotate the valve body 60, it controls the pressure equalization mechanism 80 to connect the first passage 61 and the valve chamber 31A for a predetermined time while the valve body 60 is in the first or second position. With this configuration, the high-pressure refrigerant and the low-pressure refrigerant can be sufficiently equalized, and the valve body 60 can be rotated while reducing the rotational torque of the valve body 60.

[0170] Although embodiments have been described above, it should be understood that various modifications to the form and details are possible without departing from the spirit and scope of the claims.

[0171] 10: Refrigeration device 18: Flow path switching valve 20: Control unit 30: Refrigerant circuit 31: Housing 31A: Valve chamber 40B: Drive mechanism (operating mechanism) 51b: Refrigerant flow path 52b: Refrigerant flow path 53b: Third refrigerant flow path 56b: Refrigerant flow path 60: Valve body 61: Through hole (first passage) 62: Recess (second passage) 64: Drive unit 66: Drive shaft 66a: End face 66c: Connecting passage 67: Shaft hole (connecting part) 80: Pressure equalization mechanism 81: Pressure equalization flow path 82: Opening / closing mechanism 83: Protrusion (cam receiving part; conversion part) 85b: Cam surface (conversion part) 85c: Cam surface (conversion part) 87: Closing member 88: Opening / closing operation part C2 :Rotation axis center

Claims

1. A housing (31) having a valve chamber (31A) inside, and a valve body (60) rotatably housed in the valve chamber (31A) and switchable between a first position and a second position by rotation, wherein the housing (31) has a first refrigerant flow path (52b), a second refrigerant flow path (56b), and a third refrigerant flow path (53b) that connect the valve chamber (31A) to the outside of the housing (31), and the valve body (60) connects the first refrigerant flow path (52b) and the second refrigerant flow path (56b) in the first position, and connects the first refrigerant flow path (52b) and the third refrigerant flow path (53b) in the second position, and has a first passage (61) inside through which refrigerant at a first pressure flows, A flow path switching valve having a second passage (62) through which a refrigerant at a second pressure higher than the first pressure flows, which communicates with the third refrigerant flow path (53b) in the first position and with the second refrigerant flow path (56b) in the second position, wherein the valve chamber (31A) and the second passage (62) communicate with each other when the valve body (60) is in the first or second position, and which is switchable between a configuration in which the first passage (61) and the valve chamber (31A) are connected and a configuration in which the connection is released, and which is equipped with a pressure equalization mechanism (80) that can connect the first passage (61) and the valve chamber (31A) when the valve body (60) is in the first or second position.

2. A fourth refrigerant flow path (51b) is formed in the housing (31) that connects the valve chamber (31A) to the outside of the housing (31), and the second passage (62) connects the third refrigerant flow path (53b) to the fourth refrigerant flow path (51b) in the first position, and connects the second refrigerant flow path (56b) to the fourth refrigerant flow path (51b) in the second position, the flow path switching valve according to claim 1.

3. The flow path switching valve according to claim 1 or 2, wherein the pressure equalization mechanism (80) comprises a pressure equalization flow path (81) connecting the first passage (61) and the valve chamber (31A), and an opening / closing mechanism (82) for opening and closing the pressure equalization flow path (81).

4. A flow path switching valve according to claim 3, comprising an operating mechanism (40B) for rotating the valve body (60), wherein the operating mechanism (40B) includes a drive shaft (66) positioned on the rotation axis (C2) of the valve body (60), the valve body (60) has a connecting portion (67) to which the drive shaft (66) is connected and to which the pressure equalization flow path (81) is formed, and the opening / closing mechanism (82) opens and closes the pressure equalization flow path (81) by moving the drive shaft (66).

5. The flow path switching valve according to claim 4, wherein the operating mechanism (40B) includes a drive unit (64) that rotates the drive shaft (66) for the rotational operation of the valve body (60), and the opening / closing mechanism (82) opens and closes the pressure equalizing flow path (81) by utilizing the rotation of the drive shaft (66) by the drive unit (64).

6. The flow path switching valve according to claim 5, wherein the opening / closing mechanism (82) has a conversion unit that converts the rotation of the drive shaft (66) by the drive unit (64) into movement of the drive shaft (66) in the axial direction, and the flow path switching valve opens and closes the pressure equalizing flow path (81) by moving the drive shaft (66) in the axial direction with the conversion unit.

7. The flow path switching valve according to claim 6, wherein the conversion unit is provided on one of the connecting unit (67) and the drive shaft (66) and has cam surfaces (85b, 85c) whose axial position fluctuates in the circumferential direction of the drive shaft (66), and a cam receiving unit (83) provided on the other of the connecting unit (67) and the drive shaft (66) and in contact with the cam surfaces (85b, 85c).

8. The flow path switching valve according to claim 6 or 7, wherein the drive shaft (66) has an axial end face that closes the pressure equalization flow path (81).

9. A passage (66c) communicating with the valve chamber (31A) is formed in a part of the circumferential direction of the drive shaft (66), and the opening / closing mechanism (82) rotates the drive shaft (66) by the drive unit (64) to a rotation position that connects the passage (66c) to the pressure equalizing passage (81) and to a rotation position that disconnects the communication, as described in claim 5.

10. The flow path switching valve according to claim 5, wherein the opening / closing mechanism (82) includes a closing member (87) that closes the pressure equalizing flow path (81) and moves by the rotation of the drive shaft (66), and the opening / closing mechanism (82) rotates the drive shaft (66) by the drive unit (64) to a rotation position in which the pressure equalizing flow path (81) is closed by the closing member (87) and a rotation position in which the closure is released.

11. A refrigeration system comprising a refrigerant circuit (30) including a flow path switching valve (18) according to any one of claims 1 to 10.

12. The refrigeration apparatus according to claim 11, further comprising a control unit (20) for controlling the pressure equalization mechanism (80) of the flow path switching valve (18), wherein when the control unit (20) receives a signal to rotate the valve body (60), it controls the pressure equalization mechanism (80) for a predetermined time to connect the first passage (61) and the valve chamber (31A) while the valve body (60) is in the first or second position.

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