Power transmission device and expansion valve

Abstract

The present invention is provided with: a magnetic gear (60b) having an input shaft magnet (20) for inputting rotational driving force, a magnetic force modulation unit (25) for modulating magnetic flux, a multi-pole magnet (40) having a larger number of poles than the input shaft magnet, and an output shaft (41) that rotates integrally with the magnetic force modulation unit or the multi-pole magnet; and a magnetic loop (MC) in which magnetic flux from the input shaft magnet flows in parallel, the magnetic loop being formed with a torque generation path ([phi] 1) in which the magnetic flux flows from the N pole (20n) of the input shaft magnet to the S pole (20s) of the input shaft magnet via the magnetic modulation unit and the multi-pole magnet to generate torque. And a short-circuit magnetic flux path (phi 2) through which magnetic flux flows from the N pole of the input shaft magnet to the S pole of the input shaft magnet in a short-circuit manner without passing through the magnetic force modulation unit.

Description

[0001] Cross-reference to related applications

[0002] This application is based on Japanese Patent Application No. 2022-103445 filed on June 28, 2022, and the contents described therein are incorporated herein by reference. Technical Field

[0003] The present invention relates to a power transmission device having a magnetic gear for transmitting power by utilizing magnetic force, and an expansion valve provided with the power transmission device. Background Art

[0004] Conventionally, such a power transmission device is described in Patent Document 1. In this prior art, a cylindrical first movable element and a second movable element are disposed coaxially with each other, and a cylindrical intermediate yoke is disposed between the first movable element and the second movable element.

[0005] The first movable element and the second movable element have a predetermined number of magnetic pole pairs along the circumferential direction. The intermediate magnetic yoke has a plurality of magnetic bodies along the circumferential direction. The number of magnetic bodies of the intermediate magnetic yoke is the same as the total number of magnetic pole pairs of the first movable element and the number of magnetic pole pairs of the second movable element.

[0006] When one of the first movable element and the second movable element rotates, the other movable element rotates due to the interaction of magnetic forces between the magnetic pole pair of the first movable element and the magnetic pole pair of the second movable element. That is, power is transmitted by generating torque between the first movable element, the second movable element and the intermediate magnetic yoke.

[0007] Prior art literature

[0008] Patent Literature

[0009] Patent Document 1: Japanese Patent No. 5958466

[0010] In a power transmission device having a magnetic gear as in the above-mentioned prior art, it is desired to effectively use the magnetic forces of the first movable element and the second movable element to increase the transmission torque as much as possible. Summary of the invention

[0011] In view of the above-mentioned points, an object of the present invention is to provide a power transmission device having a magnetic gear, and to improve the transmission torque in an expansion valve having the power transmission device.

[0012] A power transmission device according to one aspect of the present invention includes a magnetic gear and a magnetic circuit. The magnetic gear includes an input shaft magnet, a magnetic force modulation unit, a multi-pole magnet, and an output shaft.

[0013] The rotational driving force is input to the input shaft magnet. The magnetic force modulation unit modulates the magnetic flux. The number of poles of the multi-pole magnet is greater than the number of poles of the input shaft magnet. The output shaft rotates integrally with the magnetic force modulation unit or the multi-pole magnet.

[0014] In the magnetic circuit, the magnetic flux from the input shaft magnet flows in parallel. The magnetic circuit forms a torque generation path and a short-circuit magnetic flux path. The torque generation path allows the magnetic flux to flow from the N pole of the input shaft magnet through the magnetic force modulation unit and the multi-pole magnet to the S pole of the input shaft magnet to generate torque. In the short-circuit magnetic flux path, the magnetic flux flows from the N pole of the input shaft magnet to the S pole of the input shaft magnet without passing through the magnetic force modulation unit and short-circuiting.

[0015] Thus, by forming a short-circuit magnetic flux path, it is possible to increase the magnetic flux flowing in the torque generation path, thereby increasing the transmission torque.

[0016] An expansion valve according to one aspect of the present invention includes a power transmission device, a valve port forming member, and a valve core. The power transmission device includes a magnetic gear and a magnetic circuit. The magnetic gear includes an input shaft magnet, a magnetic force modulation unit, a multi-pole magnet, and an output shaft.

[0017] The rotational driving force is input to the input shaft magnet. The magnetic force modulation unit modulates the magnetic flux. The number of poles of the multi-pole magnet is greater than the number of poles of the input shaft magnet. The output shaft rotates integrally with the magnetic force modulation unit or the multi-pole magnet. In the magnetic force circuit, the magnetic flux from the input shaft magnet flows in parallel.

[0018] The valve port forming member forms a valve port through which the refrigerant of the vapor compression refrigeration cycle flows, and the valve element adjusts the opening of the valve port by the torque transmitted by the power transmission device.

[0019] The magnetic circuit forms a torque generation path and a short-circuit magnetic flux path. The torque generation path allows magnetic flux to flow from the N pole of the input shaft magnet to the S pole of the input shaft magnet via the magnetic force modulation unit and the multi-pole magnet to generate torque. In the short-circuit magnetic flux path, magnetic flux flows from the N pole of the input shaft magnet to the S pole of the input shaft magnet without passing through the magnetic force modulation unit and short-circuiting.

[0020] Thus, by forming the short-circuit magnetic flux path, the magnetic flux flowing in the torque generation path can be increased, thereby improving the transmission torque. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The above-mentioned object and other objects, features and advantages of the present invention will become more apparent through the following detailed description made with reference to the accompanying drawings.

[0022] Figure 1 It is an overall configuration diagram of the vehicle air conditioning device according to the first embodiment.

[0023] Figure 2 It is a cross-sectional view of the first expansion valve according to the first embodiment.

[0024] Figure 3 yes Figure 2 III-III cross-sectional view.

[0025] Figure 4 1 is a block diagram showing an electronic control unit of the vehicle air conditioning system according to the first embodiment.

[0026] Figure 5 This is a circuit diagram showing a magnetic circuit formed by the magnetic gear according to the first embodiment.

[0027] Figure 6 This is a graph showing the relationship between magnetic permeability and transmission torque in the magnetic gear according to the first embodiment.

[0028] Figure 7 It is a cross-sectional view of a magnetic gear according to a second embodiment.

[0029] Figure 8 It is an exploded perspective view of a magnetic gear according to a third embodiment.

[0030] Fig. 9 It is a cross-sectional view schematically showing a magnetic gear according to a fourth embodiment. DETAILED DESCRIPTION

[0031] Hereinafter, multiple forms for implementing the present invention will be described with reference to the accompanying drawings. For parts in each embodiment corresponding to matters described in the previous embodiment, the same reference symbols are sometimes given and repeated descriptions are omitted. In the case where only a part of the structure is described in each embodiment, other embodiments previously described can also be applied to other parts of the structure. Not only can the parts that are specifically and clearly indicated as being combinable in each embodiment be combined with each other, but as long as there is no particular obstacle to the combination, the embodiments can be partially combined with each other even if it is not clearly indicated.

[0032] For the first embodiment of the present invention, refer to Figure 1 to Figure 7 The power transmission device 1 of this embodiment is applicable to the first expansion valve 113 and the second expansion valve 115 of the vapor compression refrigeration cycle 110. The vapor compression refrigeration cycle 110 is applicable to Figure 1 The vehicle air conditioner 100 is shown. The vehicle air conditioner 100 is suitable for an electric vehicle that obtains a driving force for traveling the vehicle from an electric motor for traveling.

[0033] The vehicle air conditioner 100 has three operation modes: a cooling mode for cooling the vehicle interior, a heating mode for heating the vehicle interior, and a dehumidification and heating mode for heating the vehicle interior while dehumidifying the vehicle interior. Figure 1In the figure, the refrigerant flow in the cooling mode is represented by a solid arrow, the refrigerant flow in the heating mode is represented by a dotted arrow, and the refrigerant flow in the dehumidification heating mode is represented by a double-dashed arrow.

[0034] The vehicle air conditioning device 100 includes a vapor compression refrigeration cycle 110 and a vehicle interior air conditioning unit 120 .

[0035] The vapor compression refrigeration cycle 110 includes a compressor 111 , an indoor heat exchanger 112 , a first expansion valve 113 , an outdoor heat exchanger 114 , a second expansion valve 115 , an evaporator 116 , an electromagnetic on-off valve 117 , and an accumulator 118 .

[0036] The compressor 111 is an electric compressor that sucks, compresses, and discharges refrigerant. The vapor compression refrigeration cycle 110 is a subcritical cycle in which the refrigerant pressure on the high-pressure side does not exceed the critical pressure of the refrigerant, and a Freon series refrigerant (eg, R134a) is used as the refrigerant circulating in the vapor compression refrigeration cycle 110.

[0037] The indoor heat exchanger 112 condenses the refrigerant discharged from the compressor 111 by exchanging heat with the air flowing in the vehicle interior air conditioning unit 120. The first expansion valve 113 decompresses and expands the refrigerant condensed in the indoor heat exchanger 112. The outdoor heat exchanger 114 exchanges heat between the refrigerant flowing out of the first expansion valve 113 and the outside air.

[0038] The second expansion valve 115 decompresses and expands the refrigerant flowing out of the outdoor heat exchanger 114. The evaporator 116 evaporates the refrigerant decompressed and expanded by the second expansion valve 115 by exchanging heat with air flowing in the vehicle interior air conditioning unit 120.

[0039] The electromagnetic on-off valve 117 is an electromagnetic valve that opens and closes the refrigerant flow path that allows the refrigerant flowing out of the outdoor heat exchanger 114 to bypass the second expansion valve 115 and the evaporator 116 and guide to the accumulator 118. The accumulator 118 separates the refrigerant evaporated in the evaporator 116 from the gas and liquid of the refrigerant passing through the electromagnetic on-off valve 117.

[0040] The vehicle interior air conditioning unit 120 is disposed in the vehicle interior and forms an air passage therein. In the air passage in the vehicle interior air conditioning unit 120, a blower 121, an evaporator 116, an indoor heat exchanger 112, and an air mix door 122 are disposed.

[0041] The blower 121 is an electric blower that blows air into the air passage in the vehicle interior air conditioning unit 120. The evaporator 116 is arranged downstream of the air flow relative to the blower 121. The indoor heat exchanger 112 is arranged downstream of the air flow relative to the evaporator 116. The air mixing door 122 adjusts the flow rate ratio of the air flowing into the indoor heat exchanger 112 and the air flowing bypassing the indoor heat exchanger 112. The vehicle interior air conditioning unit 120 blows the air whose temperature is adjusted by the air mixing door 122 into the vehicle interior.

[0042] In the cooling mode of the vehicle air conditioner 100, the electromagnetic on-off valve 117 is in a closed valve state, and the air mix door 122 blocks the air flow path to the indoor heat exchanger 112. Therefore, the refrigerant discharged from the compressor 111 does not perform heat exchange in the indoor heat exchanger 112 but passes through the indoor heat exchanger 112, flows in the order of the first expansion valve 113, the outdoor heat exchanger 114, the second expansion valve 115, the evaporator 116, and the accumulator 118, and returns to the compressor 111 from the accumulator 118.

[0043] At this time, the first expansion valve 113 is in a fully open state without throttling the flow of the refrigerant, and the second expansion valve 115 is in a valve opening degree that throttles the flow of the refrigerant. Therefore, the refrigerant condenses in the outdoor heat exchanger 114 and evaporates in the evaporator 116.

[0044] In the heating mode of the vehicle air conditioner 100, the electromagnetic on-off valve 117 is in an open valve state, the second expansion valve 115 is in a closed valve state to block the flow of refrigerant, and the air mix door 122 is opened to allow air to flow to the indoor heat exchanger 112. Therefore, the refrigerant discharged from the compressor 111 flows in the order of the indoor heat exchanger 112, the first expansion valve 113, the outdoor heat exchanger 114, the electromagnetic on-off valve 117, and the accumulator 118, and returns to the compressor 111 from the accumulator 118. At this time, the first expansion valve 113 is in a valve opening degree to throttle the flow of refrigerant, and the second expansion valve 115 is in a closed valve state, so that the refrigerant condenses in the indoor heat exchanger 112, the refrigerant evaporates in the outdoor heat exchanger 114, and the refrigerant does not flow in the evaporator 116.

[0045] In the dehumidification and heating mode of the vehicle air conditioner 100, the electromagnetic on-off valve 117 is in a closed state, and the air mix door 122 is opened to allow air to flow to the indoor heat exchanger 112. Therefore, the refrigerant discharged from the compressor 111 flows in the order of the indoor heat exchanger 112, the first expansion valve 113, the outdoor heat exchanger 114, the second expansion valve 115, the evaporator 116, and the accumulator 118, and returns to the compressor 111 from the accumulator 118.

[0046] At this time, the first expansion valve 113 and the second expansion valve 115 are at valve openings that throttle the flow of the refrigerant, so that the refrigerant condenses in the indoor heat exchanger 112 and evaporates in the outdoor heat exchanger 114 and the evaporator 116 .

[0047] like Figure 2 As shown, the first expansion valve 113 has a power transmission device 1, a driving side mechanism 10 and a driven side mechanism 35. The first expansion valve 113 is arranged longitudinally on the vehicle. The longitudinal arrangement means that the axial direction of the valve core 48 is roughly parallel to the vertical direction of the vehicle, and the driving side mechanism 10 is located on the upper side of the vehicle relative to the driven side mechanism 35.

[0048] The power transmission device 1 transmits the rotational driving force generated by the driving-side mechanism portion 10 to the driven-side mechanism portion 35 by using magnetic force.

[0049] The driving side mechanism 10 includes a motor 11 and a motor case 15. The motor 11 is a motor that can be driven by speed feedback control and includes a stator 12, a rotor 13, and a shaft 14. The motor 11 is, for example, a three-phase brushless motor or a DC brush motor.

[0050] The shaft 14 is an output shaft of the motor unit 11 and an input shaft of the power transmission device 1, and rotates integrally with the rotor 13. The motor housing 15 accommodates the motor unit 11.

[0051] The stator 12 is fixed to the motor case 15. The stator 12 has a stator coil 12a. In this example, the number of slots Ns of the stator 12 is six.

[0052] The rotor 13 is cylindrical, and the stator 12 is arranged inside the rotor 13. Figure 3 As shown, the rotor 13 is provided with a plurality of pairs of magnets consisting of N poles 13n and S poles 13s in the circumferential direction. In this example, there are four N poles 13n and four S poles 13s, respectively, so the number of poles Pr of the rotor 13 is 8. The stator 12 and the rotor 13 output a driving force for rotating the shaft 14 through electromagnetic force.

[0053] The motor housing 15 is provided with an aligning portion 15a for aligning (centering) the shaft 14 of the driving-side mechanism portion 10 and the rotating member 41 of the driven-side mechanism portion 35. The aligning portion 15a is fitted with the main body portion 50 of the driven-side mechanism portion 35.

[0054] The electric circuit unit 70 is housed in the motor case 15 . The electric circuit unit 70 includes a circuit board on which a plurality of electronic components for controlling the motor unit 11 are mounted.

[0055] The driven-side mechanism portion 35 includes a rotating member 41 , a valve element 48 , a bearing member 49 , and a main body portion 50 .

[0056] The rotating member 41, the valve core 48 and the bearing member 49 are accommodated in the main body 50. The main body 50 and the motor housing 15 constitute a frame of the first expansion valve 113. The main body 50 is formed with a valve chamber 52, an inlet side connection port 53, an outlet side connection port 54 and a valve seat 55. The main body 50 is a valve port forming member that forms a valve port 52a of the valve chamber 52.

[0057] The rotating member 41 is an output shaft of the power transmission device 1, and is rotated by the driving force transmitted from the driving side mechanism portion 10. The rotating member 41 is a rod-shaped member, and is arranged coaxially with the shaft 14. An engagement groove 41a is formed at the end of the rotating member 41 on the opposite side of the driving side mechanism portion 10. The rotating member 41 is supported by a bearing member 49 fixed to the main body portion 50 so as to be rotatable.

[0058] The valve element 48 is a rod-shaped member disposed in the valve chamber 52. The valve element 48 is disposed coaxially with the rotating member 41. The protruding piece 48a of the valve element 48 meshes with the meshing groove 41a of the rotating member 41. Thus, the rotational force of the rotating member 41 is transmitted to the valve element 48.

[0059] The protruding piece 48a is formed at one end of the valve core 48. An external thread is formed on the outer peripheral surface of the valve core 48. The external thread of the valve core 48 is screwed into a screw hole 50a formed in the main body 50 to form a screw mechanism. As a result, when the valve core 48 rotates, the valve core 48 moves in the axial direction.

[0060] The valve core 48 is formed of a plurality of parts. Specifically, the valve core 48 is composed of an external threaded part 481 located on the rotating part 41 side and forming the external thread, a valve seat side part 482 located on the valve seat 55 side, and a ball 483 disposed between the two parts 481 and 482. By disposing the ball 483 between the two parts 481 and 482, the valve seat side part 482 in the valve core 48 does not rotate but moves in the axial direction.

[0061] The valve seat side member 482 serving as the ball seat member of the valve body 48 is urged by the coil spring 47 toward the side of the valve body 48 that is away from the valve seat 55 in the axial direction.

[0062] The valve core 48 moves axially so that the valve core 48 abuts against or leaves the valve seat 55, thereby opening and closing the valve port 52a of the valve chamber 52. In the valve chamber 52, the valve core 48 leaves the valve seat 55, and the refrigerant flows from the inlet side connection port 53 to the outlet side connection port 54 through the valve port 52a to be decompressed and expanded.

[0063] The power transmission device 1 includes a non-contact coupling portion 60. The non-contact coupling portion 60 includes a magnetic gear 60b and a partition wall 51. The magnetic gear 60b includes a driving side magnet 20, a magnetic pole piece 25, and a fixed magnet 40.

[0064] The driving magnet 20 is an input shaft magnet that rotates integrally with the shaft 14 of the motor unit 11. The pole piece 25 is a magnetic force modulation unit that modulates magnetic flux between the driving magnet 20 and the fixed magnet 40, and rotates integrally with the rotating member 41. The fixed magnet 40 is fixed to the main body 50 of the first expansion valve 113.

[0065] The driving side magnet 20 is cylindrical and is joined to the outer peripheral surface of the rotor 13 of the motor unit 11 via a cylindrical interposer 21. That is, the motor unit 11 is arranged inside the driving side magnet 20. The interposer 21 is formed of a magnetic body.

[0066] The driving side magnet 20 includes at least one pair of magnets consisting of an N pole 20n and an S pole 20s arranged in the circumferential direction. In this example, there are one N pole 20n and one S pole 20s, so the number of poles Pin of the driving side magnet 20 is two.

[0067] The number of poles Pin of the driving side magnet 20 is equal to the value obtained by subtracting the number of slots Ns of the stator 12 from the number of poles Pr of the rotor 13. In this example, the number of poles Pr of the rotor 13 is 8, the number of slots Ns of the stator 12 is 6, and thus the number of poles Pin of the driving side magnet 20 is 2.

[0068] The partition wall 51 is a sealing member that divides the internal space of the first expansion valve 113 into a driving side space 113a and a driven side space 113b and seals the driven side space 113b. The driving side space 113a is a space on the driving side mechanism unit 10 side, and the driven side space 113b is a space on the driven side mechanism unit 35 side.

[0069] The partition wall 51 prevents the refrigerant (high-pressure refrigerant) in the driven side space 113b from leaking into the driving side space 113a. In this example, the partition wall 51 is a component having a predetermined magnetic permeability. For example, the partition wall 51 is formed of stainless steel that has been imparted with magnetism by transforming austenitic stainless steel such as SUS305 into martensite through work hardening.

[0070] The partition wall 51 is connected to the main body 50. The partition wall 51 and the main body 50 form a pressure container having pressure resistance.

[0071] The partition wall 51 is in the shape of a disk with a center portion concave downward, and has a sealing upper surface portion 51a, a sealing cylindrical portion 51b, and a sealing bottom portion 51c. The sealing upper surface portion 51a is in the shape of an annular plate, and the outer edge portion is fixed to the main body 50 of the first expansion valve 113. The sealing cylindrical portion 51b is cylindrical and is located on the outer diameter side of the driving side magnet 20. The sealing bottom portion 51c is located on the lower side of the driving side magnet 20, and blocks the sealing cylindrical portion 51b from the driving side space 113a side.

[0072] The sealing bottom surface portion 51c is in the shape of a disk with the center portion bent downward. The corner forming the boundary between the sealing cylindrical portion 51b and the sealing bottom surface portion 51c is not a right angle but is rounded with a predetermined radius of curvature, thereby improving pressure resistance.

[0073] The partition wall 51 is formed by integrally forming a seal upper surface portion 51 a , a seal cylindrical portion 51 b , and a seal bottom surface portion 51 c in order to improve pressure resistance.

[0074] The seal bottom surface portion 51c is disposed in the gap between the shaft 14 and the rotating member 41 in the axial direction of the shaft 14 and the rotating member 41. That is, the seal bottom surface portion 51c is disposed at a location where there are few torque generating points. Therefore, it is easy to ensure the torque resistance and pressure resistance of the partition wall 51.

[0075] The pole piece 25 has a cylindrical shape and is disposed on the outer diameter side of the sealing cylindrical portion 51b of the partition wall 51. The pole piece 25 is joined to the rotating member 41 of the driven-side mechanism portion 35.

[0076] The fixed magnet 40 is cylindrical and is disposed on the outer diameter side of the magnetic pole piece 25. The fixed magnet 40 is embedded in the cylindrical main body cylinder 50b (in other words, the frame cylinder) in the main body 50 (in other words, the frame) via the cylindrical back yoke 56. The back yoke 56 and the main body cylinder 50b are formed of a magnetic body.

[0077] The fixed magnet 40 is composed of a plurality of pairs of magnets consisting of N poles 40n and S poles 40s arranged at approximately equal intervals in the circumferential direction. The number of poles Pf of the fixed magnet 40 is greater than the number of poles Pin of the drive side magnet 20. In this example, there are 20 N poles 40n and 20 S poles 40s, respectively, so the number of poles Pf of the fixed magnet 40 is 40. The fixed magnet 40 is a multi-pole magnet having a greater number of poles than the drive side magnet 20.

[0078] The magnetic pole piece 25 has a plurality of magnetic body parts 25a and a plurality of non-magnetic body parts 25b. The magnetic body parts 25a and the non-magnetic body parts 25b are in a fan-shaped trapezoidal shape, and the magnetic body parts 25a are arranged at approximately equal intervals along the circumferential direction. The non-magnetic body parts 25b are arranged between the magnetic body parts 25a. For example, the magnetic body parts 25a are formed of a soft magnetic body (such as an iron-based metal), and the non-magnetic body parts 25b are formed of a non-magnetic body (such as stainless steel or resin).

[0079] The number of poles Pp of the pole piece 25 is the same as the sum of the number of poles Pin of the drive side magnet 20 and the number of poles Pf of the fixed magnet 40. In this example, the number of poles Pin of the drive side magnet 20 is 2, and the number of poles Pf of the fixed magnet 40 is 40, so the number of poles Pp of the pole piece 25 is 42. That is, the number of magnetic body parts 25a and the number of non-magnetic body parts 25b are 21 each. That is, the number Npp of the magnetic body parts 25a relative to the number of poles Pin of the drive side magnet 20 and the number of poles Pf of the fixed magnet 40 is as follows:

[0080] Npp=(Pin+Pf) / 2

[0081] The axial length of the pole piece 25 is shorter than the axial length of the fixed magnet 40. This can reduce the magnetic flux leakage in the axial direction of the pole piece 25 and improve the transmission torque.

[0082] The configuration of the second expansion valve 115 is the same as that of the first expansion valve 113 , and thus a detailed description of the configuration of the second expansion valve 115 will be omitted.

[0083] Next, an overview of the electric control unit of this embodiment will be described. Figure 4 The air conditioning control device 80, the first expansion valve control device 81, and the second expansion valve control device 82 shown are well-known microcomputers including a CPU, a ROM, a RAM, etc., and an electronic control unit having peripheral circuits. The air conditioning control device 80, the first expansion valve control device 81, and the second expansion valve control device 82 perform various calculations and processes according to the control program stored in the ROM to control the actions of various control target devices connected to the output side.

[0084] The first expansion valve control device 81 and the second expansion valve control device 82 are connected to each other via the air conditioning control device 80 and the wiring harness so as to be able to communicate with each other. Therefore, the operation of the control target device connected to the output side of the other control device can be controlled based on the detection signal or operation signal input to one control device.

[0085] The air conditioning control device 80 controls the operation of the compressor 111 of the vapor compression refrigeration cycle 110 , the electromagnetic on-off valve 117 , the blower 121 of the vehicle interior air conditioning unit 120 , the actuator for driving the air mix door 122 , and the like.

[0086] The first expansion valve control device 81 controls the operation of the first expansion valve 113 of the refrigeration cycle 110. Specifically, the value of the drive current output to the motor unit 11 of the first expansion valve control device 81 is calculated, and the drive current is output to the motor unit 11 according to the calculation result. The first expansion valve control device 81 is composed of the circuit unit 70 of the first expansion valve 113.

[0087] The second expansion valve control device 82 controls the operation of the second expansion valve 115 of the vapor compression refrigeration cycle 110. Specifically, the value of the drive current output to the motor unit 11 of the second expansion valve control device 82 is calculated, and the drive current is output to the motor unit 11 based on the calculation result. The second expansion valve control device 82 is formed by the circuit unit 70 of the second expansion valve 115.

[0088] The input side of the air conditioning control device 80 is connected to a control sensor group such as an indoor air temperature sensor 83, an outdoor air temperature sensor 84, a sunlight sensor 85, an air conditioning wind temperature sensor 86, a high-pressure side refrigerant sensor 87, and a low-pressure side refrigerant sensor 88. Detection signals of these sensors are input to the air conditioning control device 80. These sensors are included in the components constituting the refrigeration cycle.

[0089] The indoor air temperature sensor 83 is an indoor air temperature detection unit that detects the indoor air temperature Tr, which is the temperature inside the vehicle interior. The outdoor air temperature sensor 84 is an outdoor air temperature detection unit that detects the outdoor air temperature Tam, which is the temperature outside the vehicle interior. The sunshine sensor 85 is a sunshine amount detection unit that detects the sunshine amount As irradiated into the vehicle interior. The air conditioning wind temperature sensor 86 is an air conditioning wind temperature detection unit that detects the temperature TAV of the air conditioning wind sent from the vehicle interior air conditioning unit 120 into the vehicle interior.

[0090] The high-pressure refrigerant sensor 87 is a high-pressure refrigerant detection unit that detects the pressure and temperature of the high-pressure refrigerant in the vapor compression refrigeration cycle 110. The low-pressure refrigerant sensor 88 is a low-pressure refrigerant detection unit that detects the pressure and temperature of the low-pressure refrigerant in the vapor compression refrigeration cycle 110.

[0091] The input side of the air conditioning control device 80 is also connected to various operation switches provided on the air conditioning operation panel. The air conditioning operation panel is arranged near the instrument panel in the front part of the vehicle interior. The instrument panel is arranged near the front of the driver's seat in the front part of the vehicle interior. The instrument panel displays various information such as the driving speed of the electric vehicle and the operation status of the electric vehicle. When various devices of the electric vehicle are abnormal or fail, the instrument panel warns the passengers through display, sound, etc.

[0092] Operation signals from various operation switches of the air-conditioning operation panel are input to the air-conditioning control device 80. Specifically, various operation switches provided on the air-conditioning operation panel include an automatic switch, an air-conditioning switch, an air volume setting switch, a temperature setting switch, and the like.

[0093] The automatic switch is an operation unit for the passenger to set or release the automatic control driving of the air conditioner in the vehicle interior. The air conditioner switch is an operation unit for the passenger to request the cooling of the air by the indoor evaporator. The air volume setting switch is an operation unit for the passenger to manually set the air volume of the blower 121. The temperature setting switch is an operation unit for the passenger to set the set temperature Tset in the vehicle interior.

[0094] The input side of the first expansion valve control device 81 is connected to the first current and voltage sensor 90 and the first rotation angle sensor 91. The first current and voltage sensor 90 is a first expansion valve current and voltage detection unit that detects the current and voltage supplied to the motor unit 11 of the first expansion valve 113. The first rotation angle sensor 91 is a first rotation angle detection unit that detects the rotation angle (in other words, the rotation position) of the motor unit 11 of the first expansion valve 113.

[0095] The first current and voltage sensor 90 is attached to the first expansion valve 113. In the first current and voltage sensor 90, the current detection unit and the voltage detection unit are integrated, but the current detection unit and the voltage detection unit may be configured independently.

[0096] The input side of the second expansion valve control device 82 is connected to a second current and voltage sensor 92 and a second rotation angle sensor 93. The second current and voltage sensor 92 is a second expansion valve current and voltage detection unit that detects the current and voltage supplied to the motor unit 11 of the second expansion valve 115. The second rotation angle sensor 93 is a second rotation angle detection unit that detects the rotation angle (in other words, the rotation position) of the motor unit 11 of the second expansion valve 115.

[0097] The second current and voltage sensor 92 is attached to the second expansion valve 115. In the second current and voltage sensor 92, the current detection unit and the voltage detection unit are integrated, but the current detection unit and the voltage detection unit may be configured independently.

[0098] Next, the operation of the vehicle air conditioner 100 in the present embodiment will be described in general terms. The air conditioner control device 80 determines whether to execute any of the operation modes of the cooling mode, the heating mode, and the dehumidification heating mode based on detection signals from a control sensor group such as an indoor air temperature sensor 83, an outdoor air temperature sensor 84, a sunlight sensor 85, an air conditioning wind temperature sensor 86, a high-pressure side refrigerant sensor 87, and a low-pressure side refrigerant sensor 88.

[0099] The air conditioning control device 80 performs opening and closing control on the electromagnetic on-off valve 117 , the first expansion valve 113 , and the second expansion valve 115 , and switches to the determined operation mode.

[0100] In the cooling mode, the electromagnetic on-off valve 117 is in a closed state, the first expansion valve 113 is in a fully open state without throttling the refrigerant flow, and the second expansion valve 115 is in a valve opening degree that throttles the refrigerant flow. At this time, the air conditioning control device 80 determines the target throttling opening degree of the second expansion valve 115 based on the detection signal from the control sensor group, and outputs the determined target throttling opening degree to the second expansion valve control device 82. The second expansion valve control device 82 controls the second expansion valve 115 in such a way that the opening degree of the second expansion valve 115 becomes the target throttling opening degree output from the air conditioning control device 80.

[0101] In the heating mode, the electromagnetic on-off valve 117 is in an open state, the first expansion valve 113 is in a valve opening degree for throttling the flow of the refrigerant, and the second expansion valve 115 is in a closed state for blocking the flow of the refrigerant. At this time, the air conditioning control device 80 determines the target throttling opening degree of the first expansion valve 113 based on the detection signal from the control sensor group, and outputs the determined target throttling opening degree to the first expansion valve control device 81. The first expansion valve control device 81 controls the first expansion valve 113 in such a way that the opening degree of the first expansion valve 113 becomes the target throttling opening degree output from the air conditioning control device 80.

[0102] In the dehumidification and heating mode, the electromagnetic on-off valve 117 is in the closed valve state, and the first expansion valve 113 and the second expansion valve 115 are in the valve opening degree for throttling the flow of the refrigerant. At this time, the air conditioning control device 80 determines the target throttling opening degree of the first expansion valve 113 and the target throttling opening degree of the second expansion valve 115 based on the detection signal from the control sensor group, and outputs the determined target throttling opening degree to the first expansion valve control device 81 and the second expansion valve control device 82. The first expansion valve control device 81 controls the first expansion valve 113 in such a way that the opening degree of the first expansion valve 113 becomes the target throttling opening degree output from the air conditioning control device 80. The second expansion valve control device 82 controls the second expansion valve 115 in such a way that the opening degree of the second expansion valve 115 becomes the target throttling opening degree output from the air conditioning control device 80.

[0103] Next, the operation of the first expansion valve 113 in this embodiment will be described. The operation of the second expansion valve 115 is the same as that of the first expansion valve 113, and thus the description of the operation of the second expansion valve 115 will be omitted.

[0104] When the driving current is output from the first expansion valve control device 81 to the motor unit 11 of the first expansion valve 113, the rotor 13 of the motor unit 11 rotates, and the shaft 14 of the motor unit 11 also rotates integrally. When the shaft 14 of the motor unit 11 rotates and the drive side magnet 20 also rotates integrally, the magnetic pole piece 25 rotates in the same direction as the rotation direction of the drive side magnet 20 due to the interaction of the magnetic force between the drive side magnet 20 and the fixed magnet 40.

[0105] The reduction ratio at this time is equal to the value obtained by dividing the number of poles Pp of the pole piece 25 by the number of poles Pin of the drive side magnet 20. Since the number of poles Pp of the pole piece 25 is greater than the number of poles Pin of the drive side magnet 20, the rotation speed of the pole piece 25 is less than that of the drive side magnet 20.

[0106] In this example, the number of poles Pp of the pole piece 25 is 42, and the number of poles Pin of the driving side magnet 20 is 2, so the reduction ratio is 21.

[0107] On the other hand, in a configuration in which the pole piece 25 is fixed and a magnet having the same number of poles as the fixed magnet 40 is engaged with the rotating member 41 of the driven-side mechanism portion 35 for rotation (hereinafter referred to as a comparative example), the reduction ratio is 20.

[0108] Since the pole number Pp of the pole piece 25 is greater than the pole number Pf of the fixed magnet 40 , the reduction ratio in the present embodiment in which the pole piece 25 is rotated is greater than the reduction ratio in the comparative example in which a magnet having the same pole number as the fixed magnet 40 is rotated.

[0109] In the present embodiment in which the pole piece 25 is rotated, the pole piece 25 is a member independent of the partition wall 51. Therefore, the pressure resistance of the partition wall 51 can be improved compared with the conventional structure in which the pole piece is buried in the sealing plate without rotating.

[0110] The partition wall 51 has the sealing cylindrical portion 51b and the sealing bottom surface portion 51c, and thus has a disk shape with the center portion recessed toward the driven-side mechanism portion 35. Therefore, the partition wall 51 can be disposed as a member independent of the pole piece 25, and the pressure resistance of the partition wall 51 can be improved.

[0111] The number Npp of the magnetic body portions 25a of the pole piece 25 is in the following relationship with respect to the number Pin of poles of the drive side magnet 20 and the number Pf of poles of the fixed magnet 40:

[0112] Npp=(Pin+Pf) / 2

[0113] Thus, the rotational force of the drive side magnet 20 can be transmitted to the magnetic pole piece 25. The rotational force of the drive side magnet 20 is transmitted to the magnetic pole piece 25, so that the rotating member 41 as the output shaft of the power transmission device 1 rotates, and the rotational force of the rotating member 41 is transmitted to the valve core 48, so that the valve core 48 moves in the axial direction. The valve core 48 moves in the axial direction, so that the valve port 52a of the valve chamber 52 is opened and closed, and the flow rate of the refrigerant passing through the valve port 52a is adjusted.

[0114] At this time, in the non-contact connection portion 60, since the partition wall 51 is given magnetism, Figure 5As shown, the magnetic flux forms a magnetic circuit MC flowing in parallel. Figure 3 and Figure 5 The torque generation path φ1 is shown by the solid arrow, and Figure 3 and Figure 5 The short-circuit magnetic flux path φ2 shown by the dotted arrow serves as the path for the magnetic flux to flow.

[0115] In the torque generating path φ1, the magnetic flux flows in the order of the N pole 20n of the driving side magnet 20, the partition wall 51, the magnetic body 25a of the pole piece 25, the fixed magnet 40, the back yoke 56, the fixed magnet 40, the magnetic body 25a of the pole piece 25, the partition wall 51, and the S pole 20s of the driving side magnet 20. In the short-circuit magnetic flux path φ2, the magnetic flux flows in the order of the N pole 20n of the driving side magnet 20, the partition wall 51, and the S pole 20s of the driving side magnet 20.

[0116] The torque generation path φ1 is a path through which magnetic flux flows for generating torque between the magnetic pole piece 25 and the fixed magnet 40. The short-circuit magnetic flux path φ2 is a path through which magnetic flux flows without generating torque and without being short-circuited.

[0117] Figure 6 The graph shows the relationship between the magnetic permeability of the partition wall 51 and the torque (hereinafter referred to as the transmission torque) generated between the magnetic pole piece 25 and the fixed magnet 40. The magnetic permeability of the partition wall 51 is between the magnetic permeability of a vacuum and the magnetic permeability of iron. The upper part of this graph is convex, and the magnetic permeability is a predetermined value ( Figure 6 The transmitted torque is maximum when the load is about 30% in the example.

[0118] In the low permeability region, the transmission torque increases as the permeability of the partition wall 51 increases. This is because the magnetic flux penetrating the partition wall 51 increases, and the magnetic flux flowing in the torque generation path φ1 also increases. On the other hand, in the high permeability region, the transmission torque decreases as the permeability of the partition wall 51 increases. This is because the magnetic flux flowing in the short-circuit magnetic flux path φ2 increases significantly, and the magnetic flux flowing in the torque generation path φ1 decreases.

[0119] Based on the above description, it is preferable that the magnetic permeability of the partition wall 51 and the magnetic permeability ( Figure 6 In the example, about 30%), the difference is within ±20% ( Figure 6 More preferably, when the difference between the magnetic permeability of the partition wall 51 and the magnetic permeability when the transmission torque is maximum is within ±10% ( Figure 6 In the example of about 20% to about 40%, it is possible to generate nearly maximum torque.

[0120] In order to make the partition walls 51 have a desired magnetic permeability, the partition walls 51 are formed of stainless steel obtained by transforming austenitic stainless steel such as SUS305 into martensite by work hardening to impart magnetism. Therefore, the pressure resistance of the partition walls 51 can be improved.

[0121] In the present embodiment, a magnetic circuit MC is provided in which the magnetic flux from the drive side magnet 20 flows in parallel, and the magnetic circuit MC forms a torque generation path φ1 and a short-circuit magnetic flux path φ2. In the torque generation path φ1, the magnetic flux flows from the N pole 20n of the drive side magnet 20 to the S pole 20s of the drive side magnet 20 via the magnetic pole piece 25 and the fixed magnet 40 to generate torque. In the short-circuit magnetic flux path φ2, the magnetic flux flows from the N pole 20n of the drive side magnet 20 to the S pole 20s of the drive side magnet 20 without passing through the magnetic pole piece 25.

[0122] Thus, by forming the short-circuit magnetic flux path φ2, it is possible to increase the magnetic flux flowing in the torque generation path φ1. Therefore, it is possible to increase the transmission torque.

[0123] In the present embodiment, the partition wall 51 is disposed between the driving side magnet 20 and the magnetic pole piece 25, has a magnetic permeability higher than that of a vacuum, and forms a short-circuit magnetic flux path φ2. Thus, the short-circuit magnetic flux path φ2 can be formed satisfactorily.

[0124] In the present embodiment, the magnetic permeability of the partition wall 51 is between the magnetic permeability of a vacuum and the magnetic permeability of iron. Specifically, the difference between the magnetic permeability of the partition wall 51 and the magnetic permeability when the torque is maximum is within ±20%. More specifically, the difference between the magnetic permeability of the partition wall 51 and the magnetic permeability when the torque is maximum is within ±10%.

[0125] Thus, the amount of magnetic flux flowing in the torque generation path φ1 can be appropriately increased, and thus the transmission torque can be improved.

[0126] In the present embodiment, the partition walls 51 are made of austenitic stainless steel having martensite. This makes it possible to easily form the partition walls 51 having an appropriate magnetic permeability and to increase the strength of the partition walls 51.

[0127] In this embodiment, the partition wall 51 is divided into a driving side space 113a as a space on the driving side magnet 20 side and a driven side space 113b as a space on the magnetic pole piece 25 side. This can reduce the number of parts compared to the case where the member forming the short-circuit magnetic flux path φ2 is formed as a separate member from the partition wall 51.

[0128] In this embodiment, the partition wall 51 forms a part of the pressure vessel that seals the driven side space 113b with pressure resistance. This can reduce the number of parts compared to the case where the member forming the short-circuit magnetic flux path φ2 is formed as a separate member from the pressure vessel.

[0129] (Second Embodiment)

[0130] In the first embodiment, the partition wall 51 is formed of stainless steel obtained by transforming austenitic stainless steel such as SUS305 into martensite by work hardening to impart magnetism. Figure 7 As shown, the partition wall 51 is formed by laminating a non-magnetic layer 511 and a magnetic layer 512 .

[0131] The non-magnetic layer 511 is formed of a non-magnetic body. The magnetic layer 512 is formed of a magnetic body. The magnetic permeability of the partition wall 51 can be appropriately set by appropriately setting the ratio of the non-magnetic layer 511 to the magnetic layer 512. In this embodiment, the same effects as those of the first embodiment can be achieved.

[0132] In the present embodiment, the partition wall 51 is formed of a plurality of layers, namely, the non-magnetic layer 511 and the magnetic layer 512, wherein the magnetic layer 512 is a magnetic body. Thus, the partition wall 51 having an appropriate magnetic permeability can be easily formed.

[0133] (Third Embodiment)

[0134] The magnetic gear 60b of the first embodiment is a radial type magnetic gear 60b in which the driving side magnet 20, the magnetic pole piece 25 and the fixed magnet 40 are stacked in the radial direction, while the magnetic gear 60b of the present embodiment is Figure 8 As shown, it is an axial type magnetic gear 60b in which the driving side magnet 20, the pole piece 25 and the fixed magnet 40 are stacked in the axial direction.

[0135] In this embodiment, as in the first embodiment, a magnetic circuit MC having a torque generation path φ1 and a short-circuit magnetic flux path φ2 connected in parallel with each other can be formed. Therefore, by making the partition wall 51 have a desired magnetic permeability, a large transmission torque can be generated.

[0136] (Fourth Embodiment)

[0137] The magnetic gear 60b of the first embodiment is a radial type magnetic gear 60b in which the driving side magnet 20, the magnetic pole piece 25 and the fixed magnet 40 are stacked in the radial direction, while the magnetic gear 60b of the present embodiment is Fig. 9 As shown, the driving side magnet 20, the pole piece 25 and the fixed magnet 40 are formed into a long plate shape and are stacked so as to face each other, forming a linear magnetic gear 60b.

[0138] In this embodiment, a magnetic circuit MC having a torque generation path φ1 and a short-circuit magnetic flux path φ2 connected in parallel with each other can be formed as in the first embodiment, so that a large transmission torque can be generated by making the partition wall 51 have a desired magnetic permeability.

[0139] The present invention is not limited to the above-described embodiment, and the following various modifications are possible without departing from the gist of the present invention.

[0140] In the first embodiment, the partition wall 51 is formed of stainless steel that has been imparted with magnetism by work hardening austenitic stainless steel such as SUS305 into martensite, but it may also be formed of a magnetic metal having a reduced magnetic permeability by deforming a magnetic metal such as an electromagnetic steel sheet. The partition wall 51 may also be formed of a resin mixed with iron powder.

[0141] In the first embodiment, the pole piece 25 and the fixed magnet 40 are arranged radially outside the driving side magnet 20 , but the pole piece 25 and the fixed magnet 40 may be arranged radially inside the driving side magnet 20 .

[0142] In the above-mentioned embodiment, an example of applying the present invention to an expansion valve of a vapor compression refrigeration cycle is shown, but the present invention is not limited to the expansion valve, and can also be applied to various electric valves that open and close a valve port through which a fluid passes by a valve core. In addition to being applicable to electric valves, the present invention can also be applied to power transmission devices that transmit power from various driving-side devices to various driven-side devices.

[0143] The present invention has been described based on the embodiments, but it should be understood that the present invention is not limited to the embodiments and structures. The present invention includes various modifications and variations within the scope of equality. In addition, various combinations and forms, and further combinations and forms containing only one element, above or below it, also fall within the scope and thought range of the present invention.

[0144] The features of the power transmission device and the expansion valve disclosed in this specification are as follows.

[0145] (Item 1)

[0146] A power transmission device comprising:

[0147] A magnetic gear (60b) comprising an input shaft magnet (20) for inputting a rotational driving force, a magnetic force modulation portion (25) for modulating magnetic flux, a multi-pole magnet (40) having a greater number of poles than the input shaft magnet, and an output shaft (41) that rotates integrally with the magnetic force modulation portion or the multi-pole magnet; and

[0148] a magnetic circuit (MC) in which the magnetic flux from the input shaft magnet flows in parallel,

[0149] The magnetic circuit is formed by:

[0150] a torque generating path (φ1) for allowing magnetic flux to flow from the N pole (20n) of the input shaft magnet to the S pole (20s) of the input shaft magnet via the magnetic force modulation unit and the multi-pole magnet to generate torque; and

[0151] A short-circuit magnetic flux path (φ2) allows magnetic flux to flow from the N pole of the input shaft magnet to the S pole of the input shaft magnet without passing through the magnetic force modulation unit.

[0152] (Item 2)

[0153] The power transmission device according to item 1 comprises a short-circuit magnetic flux forming member (51) which is arranged between the input shaft magnet and the magnetic force modulation unit, has a magnetic permeability higher than that of a vacuum, and forms the short-circuit magnetic flux path.

[0154] (Item 3)

[0155] In the power transmission device described in item 2, the magnetic permeability of the short-circuit magnetic flux forming member is a magnetic permeability between the magnetic permeability of vacuum and the magnetic permeability of iron.

[0156] (Item 4)

[0157] In the power transmission device according to item 2 or 3, the difference between the magnetic permeability of the short-circuit magnetic flux forming member and the magnetic permeability when the torque is maximum is within ±20%.

[0158] (Item 5)

[0159] In the power transmission device according to any one of items 2 to 4, a difference between a magnetic permeability of the short-circuit magnetic flux forming member and a magnetic permeability when the torque is maximum is within ±10%.

[0160] (Item 6)

[0161] In the power transmission device according to any one of items 2 to 5, the short-circuit magnetic flux forming member is formed of a plurality of layers, and a part of the plurality of layers is a magnetic body.

[0162] (Item 7)

[0163] In the power transmission device according to any one of items 2 to 5, the short-circuit magnetic flux forming member is made of austenitic stainless steel and has martensite.

[0164] (Item 8)

[0165] In the power transmission device as described in any one of items 2 to 7, the short-circuit flux forming component is a partition wall (51) which divides the space into a driving side space (113a) which is the space on the input shaft magnet side, and a driven side space (113b) which is the space on the magnetic force modulation part side.

[0166] (Item 9)

[0167] In the power transmission device described in item 8, the short-circuit magnetic flux forming member forms a part of a pressure container (50, 51) that seals the driven side space in a pressure-resistant manner.

[0168] (Item 10)

[0169] An expansion valve, comprising:

[0170] The power transmission device (1) according to any one of items 1 to 9;

[0171] a valve port forming member (50) which forms a valve port (52a) through which a refrigerant of a vapor compression refrigeration cycle (110) flows; and

[0172] A valve core (48) is used to adjust the opening of the valve port by the torque transmitted by the power transmission device.

Claims

1. A power transmission device, characterized in that: have: A magnetic gear (60b) comprising an input shaft magnet (20) for inputting a rotational driving force, a magnetic force modulation portion (25) for modulating magnetic flux, a multi-pole magnet (40) having a greater number of poles than the input shaft magnet, and an output shaft (41) that rotates integrally with the magnetic force modulation portion or the multi-pole magnet; and a magnetic circuit (MC) in which the magnetic flux from the input shaft magnet flows in parallel, The magnetic circuit is formed by: a torque generating path (φ1) for allowing magnetic flux to flow from the N pole (20n) of the input shaft magnet to the S pole (20s) of the input shaft magnet via the magnetic force modulation unit and the multi-pole magnet to generate torque; as well as A short-circuit magnetic flux path (φ2) allows magnetic flux to flow from the N pole of the input shaft magnet to the S pole of the input shaft magnet without passing through the magnetic force modulation unit.

2. The power transmission device according to claim 1, characterized in that: A short-circuit magnetic flux forming member (51) is provided, which is arranged between the input shaft magnet and the magnetic force modulation unit, has a magnetic permeability higher than that of a vacuum, and forms the short-circuit magnetic flux path.

3. The power transmission device according to claim 2, characterized in that: The magnetic permeability of the short-circuit magnetic flux forming member is between the magnetic permeability of vacuum and the magnetic permeability of iron.

4. The power transmission device according to claim 2, characterized in that: The difference between the magnetic permeability of the short-circuit magnetic flux forming member and the magnetic permeability when the torque is maximum is within ±20%.

5. The power transmission device according to claim 2, characterized in that: The difference between the magnetic permeability of the short-circuit magnetic flux forming member and the magnetic permeability when the torque is maximum is within ±10%.

6. The power transmission device according to claim 2, characterized in that: The short-circuit magnetic flux forming member is formed of a plurality of layers (511, 512), and a portion of the layers (512) of the plurality of layers is a magnetic body.

7. The power transmission device according to claim 2, characterized in that: The short-circuit magnetic flux forming member is made of austenitic stainless steel and has martensite.

8. The power transmission device according to claim 2, characterized in that: The short-circuit magnetic flux forming member is a partition wall (51) which is divided into a driving side space (113a) as a space on the input shaft magnet side and a driven side space (113b) as a space on the magnetic force modulation unit side.

9. The power transmission device according to claim 8, characterized in that: The short-circuit magnetic flux forming member forms a part of a pressure container (50, 51) which seals the driven side space in a pressure-resistant manner.

10. An expansion valve, characterized in that: have: A power transmission device (1) comprising a magnetic gear (60b) and a magnetic circuit (MC), the magnetic gear having an input shaft magnet (20) for inputting a rotational driving force, a magnetic force modulation unit (25) for modulating magnetic flux, a multi-pole magnet (40) having a greater number of poles than the input shaft magnet, and an output shaft (41) that rotates integrally with the magnetic force modulation unit or the multi-pole magnet, wherein the magnetic flux from the input shaft magnet flows in parallel in the magnetic circuit; a valve port forming member (50) which forms a valve port (52a) through which a refrigerant of a vapor compression refrigeration cycle (110) flows; and a valve core (48) which adjusts the opening of the valve port by the torque transmitted by the power transmission device, The magnetic circuit is formed by: a torque generating path (φ1) for allowing magnetic flux to flow from the N pole (20n) of the input shaft magnet to the S pole (20s) of the input shaft magnet via the magnetic force modulation unit and the multi-pole magnet to generate torque; as well as A short-circuit magnetic flux path (φ2) allows magnetic flux to flow from the N pole of the input shaft magnet to the S pole of the input shaft magnet without passing through the magnetic force modulation unit.

Images