Electric valve

Abstract

The present invention comprises a motor unit (11) that generates rotational driving force when electric power is supplied, a valve opening forming member (50) that forms a valve opening (52a) through which a fluid passes, a valve body (48) that opens and closes the valve opening, a magnetic gear (60b) that magnetically transmits rotational power from an output shaft (14) of the motor unit to the valve body, and a control unit (81) that controls the current supplied to the motor unit. The control unit limits the current supplied to the motor unit to no more than a fully-closed limiting current (Is) during fully-closed operation when the valve opening has been fully closed by the valve body. The fully-closed limiting current value is greater than an opening-degree adjustment current value (Ia), which is the value of the current supplied to the motor unit during an opening-degree adjustment when the degree to which the valve opening is open is being adjusted by the valve body.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Japanese Patent Application No. 2022-101834, filed on June 24, 2022, the contents of which are incorporated herein by reference. [Technical Field]

[0002] The present disclosure relates to an electrically operated valve that is driven to open and close by an electric motor. [Background technology]

[0003] A conventional motor-operated valve of this type is described in Patent Document 1. In this conventional technology, an electric motor drives a main valve element, which then seats on a main valve seat, thereby closing the main valve port and bringing the valve into a closed state. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-34140 Summary of the Invention

[0005] In motor-operated valves, it is necessary to effectively seal the fluid so that the fluid whose flow rate is being adjusted does not enter the electric motor. One possible solution to this problem is to use a magnetic gear that magnetically transmits the rotational driving force in the mechanism that transmits the rotational driving force from the electric motor to the valve body.

[0006] However, with this measure, if the torque of the electric motor exceeds the step-out torque of the magnetic gear, the magnetic gear will step out of step and will begin to rotate forward and backward repeatedly, making it impossible to reliably close the valve and resulting in fluid leakage.

[0007] In view of the above, the present disclosure aims to reduce fluid leakage when a motor-operated valve having a magnetic gear is fully closed.

[0008] An electric valve according to one aspect of the present disclosure includes a motor unit, a valve opening forming member, a valve body, a magnetic gear, and a control unit.

[0009] The motor unit generates a rotational driving force when power is supplied to it. The valve orifice forming member forms a valve orifice through which fluid passes. The valve disc opens and closes the valve orifice. The magnetic gear magnetically transmits the rotational driving force from the output shaft of the motor unit to the valve disc. The control unit controls the current supplied to the motor unit.

[0010] The control unit limits the current supplied to the motor unit to a fully closed limit current value or less during a fully closed operation in which the valve element fully closes the valve port. The fully closed limit current value is a current value greater than the current value during opening adjustment. The current value during opening adjustment is the value of the current supplied to the motor unit during opening adjustment in which the valve element adjusts the opening of the valve port.

[0011] This prevents the magnetic gear from losing synchronization due to excessive current being supplied to the motor during full-close operation, thereby preventing the valve disc from rotating reversely due to loss of synchronization, thereby improving the full closure of the valve port. [Brief explanation of the drawings]

[0012] The above and other objects, features and advantages of the present disclosure will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. [Figure 1] 1 is an overall configuration diagram showing a vehicle air conditioner according to a first embodiment. [Figure 2] FIG. 2 is a cross-sectional view showing a first expansion valve of the first embodiment. [Figure 3] FIG. 3 is a cross-sectional view taken along the line III-III in FIG. 2. [Figure 4] 1 is a block diagram showing an electronic control unit of a vehicle air conditioner according to a first embodiment. [Figure 5] 4 is a graph showing the relationship between torque and current in a motor unit of the first expansion valve of the first embodiment. [Figure 6]4 is a graph illustrating a failure detection current value and a fully closed limit current value stored in the first expansion valve control device of the first embodiment. [Figure 7] 4 is a flowchart showing a control process executed by a first expansion valve control device of the first embodiment. [Figure 8] 10 is a graph illustrating a failure detection current value and a fully closed limit current value stored in a first expansion valve control device of a second embodiment. [Figure 9] 10 is a graph illustrating a failure detection current value and a fully closed limit current value stored in a first expansion valve control device of a third embodiment. [Figure 10] 10 is a graph illustrating a failure detection current value and a limit current value at full closure stored in a first expansion valve control device of a fourth embodiment. [Figure 11] 10 is a flowchart showing a control process executed by a first expansion valve control device of a fifth embodiment. [Figure 12] 10 is a flowchart showing a control process executed by a first expansion valve control device of a sixth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, several embodiments for carrying out the present disclosure will be described with reference to the drawings. In each embodiment, parts corresponding to matters described in the preceding embodiment will be assigned the same reference numerals, and duplicated explanations may be omitted. In each embodiment, when only a part of the configuration is described, other previously described embodiments may be applied to the other parts of the configuration. In addition to combinations of parts that are specifically specified as being combinable in each embodiment, it is also possible to partially combine embodiments even if not specified, as long as there is no particular problem with the combination.

[0014] (First embodiment) A first embodiment of the present disclosure will be described with reference to Figures 1 to 7. A power transmission device 1 of this embodiment is applied to a first expansion valve 113 and a second expansion valve 115 of a vapor compression refrigeration cycle 110. The vapor compression refrigeration cycle 110 is applied to a vehicle air conditioner 100 shown in Figure 1. The vehicle air conditioner 100 is applied to an electric vehicle that obtains driving power for running the vehicle from an electric motor for running the vehicle.

[0015] The vehicle air conditioner 100 has three operating modes: a cooling mode for cooling the vehicle interior, a heating mode for heating the vehicle interior, and a dehumidifying and heating mode for heating and dehumidifying the vehicle interior. In Fig. 1, the refrigerant flow in the cooling mode is indicated by a solid arrow, the refrigerant flow in the heating mode is indicated by a dashed arrow, and the refrigerant flow in the dehumidifying and heating mode is indicated by a two-dot chain arrow.

[0016] The vehicle air conditioner 100 includes a vapor compression refrigeration cycle 110 and a vehicle interior air conditioning unit 120 .

[0017] The vapor compression refrigeration cycle 110 has 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 .

[0018] The compressor 111 is an electric compressor that draws in, compresses, and discharges a refrigerant. The vapor compression refrigeration cycle 110 is a subcritical cycle in which the high-pressure side refrigerant pressure does not exceed the critical pressure of the refrigerant, and a fluorocarbon refrigerant (e.g., R134a) is used as the refrigerant circulating through the vapor compression refrigeration cycle 110.

[0019] The indoor heat exchanger 112 condenses the refrigerant discharged from the compressor 111 by exchanging heat with the air flowing inside 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 from the first expansion valve 113 and outside air.

[0020] The second expansion valve 115 reduces the pressure and expands the refrigerant that has flowed out from the exterior heat exchanger 114. The evaporator 116 evaporates the refrigerant that has been reduced in pressure and expanded by the second expansion valve 115 by exchanging heat with the air flowing inside the interior air conditioning unit 120.

[0021] The electromagnetic on-off valve 117 is a solenoid valve that opens and closes a refrigerant flow path that leads the refrigerant flowing out from the outdoor heat exchanger 114 to the accumulator 118, bypassing the second expansion valve 115 and the evaporator 116. The accumulator 118 separates the refrigerant evaporated in the evaporator 116 and the refrigerant that has passed through the electromagnetic on-off valve 117 into gas and liquid.

[0022] 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 interior heat exchanger 112, and an air mix door 122 are disposed.

[0023] The blower 121 is an electric blower that blows air into an air passage in the vehicle interior air conditioning unit 120. The evaporator 116 is arranged downstream of the blower 121 in the air flow. The interior heat exchanger 112 is arranged downstream of the evaporator 116 in the air flow. The air mix door 122 adjusts the flow rate ratio between the air flowing to the interior heat exchanger 112 and the air flowing bypassing the interior heat exchanger 112. The vehicle interior air conditioning unit 120 blows air whose temperature has been adjusted by the air mix door 122 into the vehicle interior.

[0024] In the cooling mode of the vehicle air conditioner 100, the electromagnetic on-off valve 117 is closed, and the air mix door 122 closes the air flow path to the indoor heat exchanger 112. Therefore, the refrigerant discharged from the compressor 111 passes through the indoor heat exchanger 112 without undergoing heat exchange therein, flows through the first expansion valve 113, the outdoor heat exchanger 114, the second expansion valve 115, the evaporator 116, and the accumulator 118 in this order, and returns from the accumulator 118 to the compressor 111.

[0025] At this time, the first expansion valve 113 is fully opened so as not to throttle the refrigerant flow, and the second expansion valve 115 is opened to throttle the refrigerant flow, so that the refrigerant is condensed in the outdoor heat exchanger 114 and evaporated in the evaporator 116.

[0026] In the heating mode of the vehicle air conditioner 100, the electromagnetic on-off valve 117 is opened, the second expansion valve 115 is closed 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 sequentially through 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 then returns from the accumulator 118 to the compressor 111. At this time, the first expansion valve 113 is opened to a degree that throttles the refrigerant flow, and the second expansion valve 115 is closed, so that the refrigerant is condensed in the indoor heat exchanger 112, evaporated in the outdoor heat exchanger 114, and does not flow to the evaporator 116.

[0027] In the dehumidifying and heating mode of the vehicle air conditioner 100, the electromagnetic on-off valve 117 is closed, 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 this order through 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 then returns to the compressor 111 from the accumulator 118.

[0028] At this time, the first expansion valve 113 and the second expansion valve 115 are opened to a degree that restricts the flow of refrigerant, so that the refrigerant is condensed in the indoor heat exchanger 112 and evaporated in the outdoor heat exchanger 114 and the evaporator 116.

[0029] 2, the first expansion valve 113 has the power transmission device 1, the drive-side mechanism unit 10, and the driven-side mechanism unit 35. The first expansion valve 113 is disposed longitudinally in the vehicle. The longitudinal disposition means that the axial direction of the valve body 48 is approximately parallel to the vertical direction of the vehicle, and the drive-side mechanism unit 10 is disposed above the driven-side mechanism unit 35.

[0030] The power transmission device 1 transmits the rotational driving force generated by the drive-side mechanism portion 10 to the driven-side mechanism portion 35 using magnetic force.

[0031] The drive-side mechanism section 10 has a motor section 11 and a motor case 15. The motor section 11 is a motor that can be driven by speed feedback control, and has a stator 12, a rotor 13, and a shaft 14. The motor section 11 is, for example, a three-phase brushless motor or a DC brush motor.

[0032] The shaft 14 is the output shaft of the motor unit 11 and also the input shaft of the power transmission device 1, and rotates integrally with the rotor 13. The motor case 15 houses the motor unit 11.

[0033] The stator 12 is fixed to a 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.

[0034] The rotor 13 is cylindrical, and the stator 12 is disposed inside the rotor 13. As shown in Fig. 3, the rotor 13 has multiple pairs of magnets, each consisting of an N pole 13n and an S pole 13s, arranged along the circumferential direction. In this example, there are four N poles 13n and four S poles 13s, so the number of poles Pr of the rotor 13 is eight. The stator 12 and the rotor 13 output a driving force that rotates the shaft 14 by electromagnetic force.

[0035] The motor case 15 is formed with an axis alignment portion 15a for axial alignment (centering) between the shaft 14 of the drive-side mechanism portion 10 and the rotating member 41 of the driven-side mechanism portion 35. The axis alignment portion 15a is fitted into the main body portion 50 of the driven-side mechanism portion 35.

[0036] A circuit section 70 is housed within the motor case 15. The circuit section 70 has a circuit board on which a plurality of electronic components for controlling the motor section 11 are mounted.

[0037] The driven-side mechanism section 35 has a rotating member 41, a valve element 48, a bearing member 49, and a main body section 50. The rotating member 41, the valve element 48, and the bearing member 49 are housed in the main body section 50. The main body section 50, together with the motor case 15, constitutes the housing of the first expansion valve 113. The main body section 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 section 50 is a valve-port forming member that forms the valve port 52a of the valve chamber 52.

[0038] The rotating member 41 is the output shaft of the power transmission device 1, and is rotated by the driving force transmitted from the drive-side mechanism 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 opposite the drive-side mechanism 10. The rotating member 41 is rotatably supported by a bearing member 49 fixed to the main body 50.

[0039] The valve element 48 is a rod-shaped member disposed within the valve chamber 52. The valve element 48 is disposed coaxially with the rotating member 41. A protruding piece 48a of the valve element 48 meshes with the meshing groove 41a of the rotating member 41. As a result, the rotational force of the rotating member 41 is transmitted to the valve element 48.

[0040] The protruding piece 48a is formed at one end of the valve body 48. A male screw is formed on the outer peripheral surface of the valve body 48. The male screw of the valve body 48 is threaded into a screw hole 50a formed in the main body 50 to form a screw mechanism. As a result, when the valve body 48 rotates, the valve body 48 moves in the axial direction.

[0041] The valve element 48 is formed of a plurality of members. Specifically, the valve element 48 is composed of a male thread member 481 located on the rotating member 41 side and having the male thread formed thereon, a valve seat side member 482 located on the valve seat 55 side, and a ball 483 disposed between the two members 481 and 482. By disposing the ball 483 between the two members 481 and 482, the valve seat side member 482 of the valve element 48 moves in the axial direction without rotating.

[0042] A valve seat side member 482 of the valve body 48, which serves as a ball receiving member, is biased by a coil spring 47 in a direction away from the valve seat 55 in the axial direction of the valve body 48.

[0043] As the valve element 48 moves in the axial direction, the valve element 48 comes into contact with or separates from the valve seat 55, thereby opening and closing the valve port 52a of the valve chamber 52. When the valve element 48 separates from the valve seat 55 in the valve chamber 52, the refrigerant flows through the valve port 52a from the inlet-side connection port 53 to the outlet-side connection port 54, where it is decompressed and expanded.

[0044] 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 sealing plate 51. The magnetic gear 60b includes a drive-side magnet 20, a pole piece 25, and a fixed magnet 40.

[0045] The drive-side magnet 20 rotates integrally with the shaft 14 of the motor unit 11. The pole piece 25 modulates the magnetic flux between the drive-side 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.

[0046] 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 intervening member 21. In other words, the motor unit 11 is disposed inside the driving-side magnet 20. The intervening member 21 is made of a magnetic material.

[0047] The driving-side magnet 20 has at least one pair of magnets, each consisting of an N pole 20n and an S pole 20s, arranged along the circumferential direction. In this example, there is one N pole 20n and one S pole 20s, so the number of poles Pin of the driving-side magnet 20 is two.

[0048] The number of poles Pin of the drive-side magnet 20 is equal to the number of poles Pr of the rotor 13 minus the number of slots Ns of the stator 12. In this example, the number of poles Pr of the rotor 13 is 8, and the number of slots Ns of the stator 12 is 6, so the number of poles Pin of the drive-side magnet 20 is 2.

[0049] The sealing plate 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.

[0050] The sealing plate 51 prevents the refrigerant (high-pressure refrigerant) present in the driven-side space 113b from leaking into the driving-side space 113a. In this example, the sealing plate 51 is made of a non-magnetic material (for example, SUS305).

[0051] The sealing plate 51 is disk-shaped with a downward recess in the center, and has a sealing upper surface 51a, a sealing cylindrical portion 51b, and a sealing bottom surface 51c. The sealing upper surface 51a is annular, and its outer edge 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 drive-side magnet 20. The sealing bottom surface 51c is located below the drive-side magnet 20, and blocks the sealing cylindrical portion 51b from the drive-side space 113a side.

[0052] The sealing bottom surface portion 51c is a disk-shaped portion whose center is curved downward. The corners forming the boundary between the sealing cylindrical portion 51b and the sealing bottom surface portion 51c are not right angles but are rounded with a predetermined radius of curvature, thereby improving pressure resistance.

[0053] In order to improve pressure resistance, the sealing plate 51 has a sealing upper surface portion 51a, a sealing cylindrical portion 51b, and a sealing bottom surface portion 51c integrally molded.

[0054] The sealing 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 sealing bottom surface portion 51c is disposed in a location where there are few torque generation points, which makes it easy to ensure the torque resistance and pressure resistance of the sealing plate 51.

[0055] The pole piece 25 is cylindrical, and is disposed on the outer diameter side of the sealing cylindrical portion 51b of the sealing plate 51. The pole piece 25 is joined to the rotating member 41 of the driven-side mechanism portion .

[0056] The fixed magnet 40 is cylindrical and is disposed on the outer diameter side of the pole piece 25. The fixed magnet 40 is fitted into a cylindrical main body cylindrical portion 50b (in other words, the cylindrical portion of the housing) of the main body portion 50 (in other words, the housing) via a cylindrical back yoke 56. The back yoke 56 and the main body cylindrical portion 50b are formed of a magnetic material.

[0057] The fixed magnet 40 is made up of a plurality of pairs of magnets, each consisting of an N pole 40n and an S pole 40s, arranged at approximately equal intervals along 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, so the number of poles Pf of the fixed magnet 40 is 40.

[0058] The pole piece 25 has a plurality of magnetic material portions 25a and a plurality of non-magnetic material portions 25b. The magnetic material portions 25a and the non-magnetic material portions 25b are frustum-shaped, and the magnetic material portions 25a are arranged at approximately equal intervals along the circumferential direction. The non-magnetic material portions 25b are arranged between the magnetic material portions 25a. For example, the magnetic material portions 25a are made of a soft magnetic material (e.g., an iron-based metal), and the non-magnetic material portions 25b are made of a non-magnetic material (e.g., stainless steel or resin).

[0059] 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, there are 21 magnetic material portions 25a and 21 non-magnetic material portions 25b. That is, the number Npp of magnetic material portions 25a has the following relationship with the number of poles Pin of the drive-side magnet 20 and the number of poles Pf of the fixed magnet 40: Npp=(Pin+Pf) / 2 The axial length of the pole piece 25 is shorter than the axial length of the fixed magnet 40. This reduces axial magnetic flux leakage at the pole piece 25, improving transmission torque.

[0060] The configuration of the second expansion valve 115 is similar to that of the first expansion valve 113, and therefore a detailed description of the configuration of the second expansion valve 115 will be omitted.

[0061] Next, an overview of the electrical control unit of this embodiment will be described. The air conditioning control device 80, first expansion valve control device 81, and second expansion valve control device 82 shown in Fig. 4 are electronic control units having a well-known microcomputer including a CPU, ROM, RAM, etc., and peripheral circuits. The air conditioning control device 80, first expansion valve control device 81, and second expansion valve control device 82 perform various calculations and processes based on control programs stored in the ROM, and control the operation of various controlled devices connected to the output side.

[0062] The first expansion valve control device 81 and the second expansion valve control device 82 are connected to the air conditioning control device 80 via a harness so that they can communicate with each other. Therefore, based on a detection signal or an operation signal input to one of the control devices, the operation of a controlled device connected to the output side of the other control device can be controlled.

[0063] 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.

[0064] The first expansion valve control device 81 controls the operation of the first expansion valve 113 of the refrigeration cycle 110. Specifically, it calculates the value of the drive current to be output to the motor unit 11 of the first expansion valve control device 81, and outputs the drive current to the motor unit 11 based on the calculation result. The first expansion valve control device 81 is composed of the circuit unit 70 of the first expansion valve 113.

[0065] 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 second expansion valve control device 82 calculates the value of the drive current to be output to the motor unit 11 of the second expansion valve control device 82, and outputs the drive current to the motor unit 11 based on the calculation result. The second expansion valve control device 82 is composed of the circuit unit 70 of the second expansion valve 115.

[0066] A group of control sensors, such as an inside air temperature sensor 83, an outside air temperature sensor 84, a solar radiation sensor 85, an air conditioning air temperature sensor 86, a high-pressure side refrigerant sensor 87, and a low-pressure side refrigerant sensor 88, are connected to the input side of the air conditioning control device 80. Detection signals from these sensors are input to the air conditioning control device 80. These sensors are included in the components that make up the refrigeration cycle.

[0067] The interior air temperature sensor 83 is an interior air temperature detection unit that detects the interior air temperature Tr, which is the temperature inside the vehicle cabin. The exterior air temperature sensor 84 is an exterior air temperature detection unit that detects the exterior air temperature Tam, which is the temperature outside the vehicle cabin. The solar radiation sensor 85 is an solar radiation amount detection unit that detects the amount of solar radiation As irradiated into the vehicle cabin. The air conditioning air temperature sensor 86 is an air conditioning air temperature detection unit that detects the temperature TAV of the conditioned air blown into the vehicle cabin from the interior air conditioning unit 120.

[0068] The high-pressure side refrigerant sensor 87 is a high-pressure side refrigerant detection unit that detects the pressure and temperature of the high-pressure side refrigerant of the vapor compression refrigeration cycle 110. The low-pressure side refrigerant sensor 88 is a low-pressure side refrigerant detection unit that detects the pressure and temperature of the low-pressure side refrigerant of the vapor compression refrigeration cycle 110.

[0069] 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 located near the instrument panel at the front of the vehicle interior. The instrument panel is located near the front of the vehicle interior directly in front of the driver's seat. The instrument panel displays various information such as the electric vehicle's traveling speed and operating status. If an abnormality or failure occurs in any of the electric vehicle's equipment, the instrument panel will warn the occupants by display, audio, etc.

[0070] Operation signals from various operation switches on the air conditioning operation panel are input to the air conditioning control device 80. Specific examples of the various operation switches provided on the air conditioning operation panel include an auto switch, an air conditioner switch, an air volume setting switch, and a temperature setting switch.

[0071] The auto switch is an operation unit that allows the occupant to activate or deactivate automatic control operation of the cabin air conditioning. The air conditioning switch is an operation unit that allows the occupant to request air cooling by the cabin evaporator. The air volume setting switch is an operation unit that allows the occupant to manually set the air volume of the blower 121. The temperature setting switch is an operation unit that allows the occupant to set the set temperature Tset in the cabin.

[0072] A first current / voltage sensor 90 and a first rotation angle sensor 91 are connected to the input side of the first expansion valve control device 81. The first current / voltage sensor 90 is a first expansion valve current / 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.

[0073] The first current / voltage sensor 90 is attached to the first expansion valve 113. In the first current / voltage sensor 90, the current detection section and the voltage detection section are integrated, but the current detection section and the voltage detection section may be configured as separate sections.

[0074] A second current / voltage sensor 92 and a second rotation angle sensor 93 are connected to the input side of the second expansion valve control device 82. The second current / voltage sensor 92 is a second expansion valve current / 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.

[0075] The second current / voltage sensor 92 is attached to the second expansion valve 115. In the second current / voltage sensor 92, the current detection section and the voltage detection section are integrated, but the current detection section and the voltage detection section may be configured as separate sections.

[0076] Next, an outline of the operation of the vehicle air conditioner 100 in this embodiment will be described. The air conditioning control device 80 determines which operating mode to execute among the cooling mode, heating mode, and dehumidifying heating mode based on detection signals from a group of control sensors, such as an inside air temperature sensor 83, an outside air temperature sensor 84, a solar radiation sensor 85, an air conditioning air temperature sensor 86, a high-pressure side refrigerant sensor 87, and a low-pressure side refrigerant sensor 88.

[0077] The air conditioning control device 80 controls the opening and closing of the electromagnetic on-off valve 117, the first expansion valve 113, and the second expansion valve 115, and switches to the determined operation mode.

[0078] In the cooling mode, the solenoid on-off valve 117 is closed, the first expansion valve 113 is fully open so as not to throttle the refrigerant flow, and the second expansion valve 115 is opened to throttle the refrigerant flow. At this time, the air conditioning control device 80 determines a target throttle opening for the second expansion valve 115 based on detection signals from the control sensors and outputs the determined target throttle opening to the second expansion valve control device 82. The second expansion valve control device 82 controls the second expansion valve 115 so that the opening of the second expansion valve 115 becomes the target throttle opening output from the air conditioning control device 80.

[0079] In the heating mode, the solenoid on-off valve 117 is opened, the first expansion valve 113 is opened to throttle the flow of refrigerant, and the second expansion valve 115 is closed to block the flow of refrigerant. At this time, the air conditioning control device 80 determines a target throttle opening for the first expansion valve 113 based on detection signals from the control sensors and outputs the determined target throttle opening to the first expansion valve control device 81. The first expansion valve control device 81 controls the first expansion valve 113 so that the opening of the first expansion valve 113 becomes the target throttle opening output from the air conditioning control device 80.

[0080] In the dehumidifying heating mode, the electromagnetic on-off valve 117 is closed, and the first expansion valve 113 and the second expansion valve 115 are set to valve openings that throttle the flow of refrigerant. At this time, the air conditioning control device 80 determines the target throttle openings of the first expansion valve 113 and the second expansion valve 115 based on detection signals from the control sensors, and outputs the determined target throttle openings to the first expansion valve control device 81 and the second expansion valve control device 82.

[0081] The first expansion valve control device 81 controls the first expansion valve 113 so that the opening degree of the first expansion valve 113 becomes the target throttle opening degree output from the air conditioning control device 80. The second expansion valve control device 82 controls the second expansion valve 115 so that the opening degree of the second expansion valve 115 becomes the target throttle opening degree output from the air conditioning control device 80.

[0082] Next, a description will be given of the operation of the first expansion valve 113 in this embodiment. The operation of the second expansion valve 115 is similar to that of the first expansion valve 113, so a description of the operation of the second expansion valve 115 will be omitted.

[0083] When a drive 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 interaction between the drive-side magnet 20 and the fixed magnet 40 causes the pole piece 25 to rotate in the same direction as the rotation of the drive-side magnet 20.

[0084] 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 smaller than the rotation speed of the drive-side magnet 20.

[0085] In this example, the number of poles Pp of the pole piece 25 is 42, and the number of poles Pin of the drive-side magnet 20 is 2, so the reduction ratio is 21.

[0086] In contrast, in a configuration in which the pole piece 25 is fixed and a magnet with the same number of poles as the fixed magnet 40 is joined to the rotating member 41 of the driven side mechanism part 35 and rotated (hereinafter, this configuration will be referred to as the comparative example), the reduction ratio is 20.

[0087] Since the number of poles Pp of the pole piece 25 is greater than the number of poles Pf of the fixed magnet 40, in this embodiment in which the pole piece 25 is rotated, the reduction ratio is greater than in the comparative example in which a magnet with the same number of poles as the fixed magnet 40 is rotated.

[0088] In this embodiment in which the pole piece 25 is rotated, the pole piece 25 is a member independent of the sealing plate 51. Therefore, compared to the conventional structure in which the pole piece does not rotate and is embedded in the sealing plate, the pressure resistance of the sealing plate 51 can be improved.

[0089] The sealing plate 51 has a cylindrical sealing portion 51b and a bottom sealing portion 51c, and thus has a disk shape with a central portion recessed toward the driven-side mechanism portion 35. Therefore, the sealing plate 51 can be disposed as a member independent from the pole piece 25, and the pressure resistance of the sealing plate 51 can be improved.

[0090] The number Npp of magnetic material portions 25a of the pole piece 25 has the following relationship with the number of poles Pin of the drive-side magnet 20 and the number of poles Pf of the fixed magnet 40: Npp=(Pin+Pf) / 2 This allows the rotational force of the drive-side magnet 20 to be transmitted to the pole piece 25. When the rotational force of the drive-side magnet 20 is transmitted to the pole piece 25, the rotating member 41, which is the output shaft of the power transmission device 1, rotates, and when the rotational force of the rotating member 41 is transmitted to the valve element 48, the valve element 48 moves in the axial direction. When the valve element 48 moves in the axial direction, the valve port 52a of the valve chamber 52 is opened or closed, and the flow rate of the refrigerant passing through the valve port 52a is adjusted.

[0091] The first expansion valve control device 81 performs feedback control of the motor unit 11 based on detection signals from the first current / voltage sensor 90 and the first rotation angle sensor 91. As shown in Fig. 5, the torque generated by the motor unit 11 (hereinafter referred to as motor torque) is proportional to the current supplied to the motor unit 11 (hereinafter referred to as motor current).

[0092] The first expansion valve control device 81 stores in advance the failure detection current value Ib and the fully closed limit current value Is shown in Fig. 6. The failure detection current value Ib (in other words, the abnormality determination current value) is a current value corresponding to the failure detection torque value Tb. The fully closed limit current value Is is a current value corresponding to the fully closed limit torque value Ts.

[0093] The fault detection torque value Tb (in other words, the abnormality determination torque value) is the motor torque value when an abnormality occurs in the operation of the valve element 48. In other words, the fault detection torque value Tb is the motor torque value when an abnormality occurs in the rotation of the motor unit 11 due to a foreign object interfering with the valve element 48, causing a sudden increase in motor torque.

[0094] The fully closed limit torque value Ts is the value of the motor torque when the valve disc 48 fully closes the valve port 52a. In other words, the fully closed limit torque value Ts is the motor torque value when the valve disc 48 is pressed against the valve seat 55 and the motor torque increases rapidly.

[0095] As shown in Figure 6, the fault detection torque value Tb is greater than the maximum motor torque Ta (hereinafter referred to as the torque value during opening adjustment) when the valve body 48 is normally adjusting the opening of the valve port 52a (in other words, during normal use), and is smaller than the base speed torque value Tv of the motor section 11 (hereinafter referred to as the motor base speed torque value).

[0096] The motor unit 11 has the characteristic that the rotational speed of the motor unit 11 (hereinafter referred to as the motor rotational speed) is constant relative to the motor torque in a range where the motor torque is smaller than the motor base speed torque value Tv, and the motor rotational speed decreases as the motor torque increases in a range where the motor torque is larger than the motor base speed torque value Tv.

[0097] As described above, since the motor torque is proportional to the motor current, the fault detection current value Ib is greater than the opening adjustment current value Ia and less than the motor base speed current value Iv. The opening adjustment current value Ia is a current value corresponding to the opening adjustment torque value Ta. The motor base speed current value Iv is a current value corresponding to the motor base speed torque value Tv.

[0098] The fully closed limit torque value Ts is greater than the motor base speed torque value Tv and less than the magnetic gear detuning torque value Tg, which is the minimum motor torque value at which the magnetic gear 60b detuning.

[0099] Therefore, the fully closed limit current value Is is greater than the motor base speed current value Iv and less than the magnetic gear detuning current value Ig, which is a current value corresponding to the magnetic gear detuning torque value Tg.

[0100] 7 is a flowchart showing the control process executed by the first expansion valve control device 81. In step S1000, an instruction signal for the operation mode of the first expansion valve 113 is input from the air conditioning control device 80. Specifically, an instruction signal for either a fully closed operation mode or an opening degree adjustment mode is input. The fully closed operation mode is an operation mode in which the first expansion valve 113 is fully closed. The opening degree adjustment mode is an operation mode in which the first expansion valve 113 is adjusted to a target opening degree.

[0101] In step S1010, it is determined whether the operation mode instructed by the air conditioning controller 80 is the fully closed operation mode, and if it is determined that it is not the fully closed operation mode (i.e., the opening degree adjustment mode), the process proceeds to step S1020.

[0102] In step S1020, a command signal for the target opening degree is input from the air conditioning control device 80. In step S1030, the failure detection current value Ib stored in advance in the air conditioning control device 80 is read out.

[0103] In step S1040, the motor unit 11 is feedback-controlled so that the rotational position of the motor unit 11 approaches the target position.

[0104] In step S1050, failure detection control (in other words, abnormality determination control) is performed. Specifically, it is determined whether or not the motor current has reached the failure detection current value Ib based on the detection signal of first current / voltage sensor 90. If it is determined in step S1050 that the motor current has not reached the failure detection current value Ib, the process proceeds to step S1060.

[0105] In step S1060, it is determined whether or not the rotational position of the motor unit 11 has reached the target position, based on the detection signal of the first rotation angle sensor 91. If it is determined that the rotational position of the motor unit 11 has not reached the target position, the process returns to step S1040.

[0106] If it is determined in step S1060 that the rotational position of the motor unit 11 has reached the target position, the process proceeds to step 1070, where a signal indicating that the motor unit 11 has reached the target position is output to the air conditioning control device 80.

[0107] On the other hand, if it is determined in step S1050 that the motor current has reached the failure detection current value Ib, the process proceeds to step S1080, in which a signal indicating expansion valve failure is sent to the air conditioning controller 80.

[0108] In other words, it is believed that the motor current became larger than the current value Ia during opening adjustment due to interference from a foreign object or the like, and therefore it is estimated that the first expansion valve 113 has failed (in other words, an abnormality has occurred in the operation of the valve body 48).

[0109] On the other hand, if it is determined in step S1010 that the operating mode instructed by the air conditioning control device 80 is the fully closed operating mode, the process proceeds to step S1100, where the fully closed limit current value Is stored in advance in the air conditioning control device 80 is read out.

[0110] In step S1110, the motor unit 11 is feedback-controlled so that the rotational position of the motor unit 11 approaches the target position (the position at which the valve element 48 is fully closed). In step S1120, it is determined whether the motor current has reached the fully closed limit current value Is based on the detection signal of the first current / voltage sensor 90. If it is determined in step S1120 that the motor current has not reached the fully closed limit current value Is, the process returns to step S1110.

[0111] If it is determined in step S1120 that the motor current has reached the fully closed limit current value Is, the process proceeds to step S1130, where a signal indicating that the valve has been closed is output to the air conditioning controller 80.

[0112] This prevents the torque of the motor unit 11 from exceeding the magnetic gear desynchronization torque value Tg, thereby preventing the magnetic gear 60b from desynchronizing and repeatedly rotating in the forward and reverse directions. As a result, the first expansion valve 113 can be reliably fully closed.

[0113] At this time, since the fully closed limit torque value Ts is greater than the motor base speed torque value Tv, the first expansion valve 113 can be reliably brought into a fully closed state with a large motor torque compared to when the fully closed limit torque value Ts is smaller than the motor base speed torque value Tv.

[0114] By the above control processing, a failure of the first expansion valve 113 can be detected when adjusting the opening of the valve port 52a using the valve body 48, and when performing a full closing operation to fully close the valve port 52a using the valve body 48, the valve port 52a can be reliably fully closed.

[0115] A configuration in which the motor base speed torque value Tv is smaller than the magnetic gear detuning torque value Tg, as in this embodiment, allows the motor size to be small, but there is a problem in that the valve cannot be closed if the magnetic gear detuning occurs during full closing operation.

[0116] In this regard, in this embodiment, by operating the motor unit 11 with a current limit applied during the full-closing operation, reverse rotation due to loss of synchronism of the magnetic gear 60b is prevented, and full closure can be ensured.

[0117] Furthermore, due to the characteristics of the magnetic gear 60b, the load torque increases gradually and deceleration occurs from when the magnetic gear 60b is seated until it is fully closed, thereby improving the sealing performance.

[0118] By not applying failure detection during the full-closing operation, refrigerant leakage can be reduced by tightening the valve disc 48 with a motor torque appropriate for closing after the valve disc 48 seats on the valve seat 55. When the full-closing operation is completed, the full-closing limit current value Is is reached, so the completion of the full-closing operation can be detected.

[0119] By applying fault detection during flow rate adjustment operation, a fault in which the output shaft of the motor unit 11 or the valve element 48 stops moving due to clogging with foreign matter or the like can be detected by the fault detection current value Ib being reached. This prevents the magnetic gear 60b from losing synchronization due to a fault, thereby preventing large fluctuations in the motor rotation speed due to loss of synchronization of the magnetic gear 60b and ultimately preventing large vibrations in the refrigerant piping.

[0120] In this embodiment, when the first expansion valve control device 81 is in the fully closed operation, the current supplied to the motor unit 11 is limited to a value not exceeding the fully closed limit current value Is. The fully closed limit current value Is is a current value larger than the current value Ia during the opening degree adjustment.

[0121] According to this, it is possible to suppress the motor current from becoming excessive during the fully closed operation and the magnetic gear 60b from getting out of synchronization. Therefore, it is possible to suppress the reverse rotation of the valve body 48 due to the out-of-synchronization of the magnetic gear 60b, and thus improve the fully closed property of the valve port 52a.

[0122] In this embodiment, the fully closed limit current value Is is a current value smaller than the magnetic gear out-of-synchronization current value Ig. According to this, it is possible to reliably suppress the magnetic gear 60b from getting out of synchronization during the fully closed operation.

[0123] In this embodiment, the first expansion valve control device 81 performs failure detection control. In the failure detection control, when the current supplied to the motor unit 11 reaches the failure detection current value Ib, it is determined that the first expansion valve 113 has failed. The failure detection current value Ib is a current value larger than the current value Ia during the opening degree adjustment and smaller than the fully closed limit current value Is. According to this, it is possible to detect that the first expansion valve 113 has failed before the magnetic gear 60b gets out of synchronization.

[0124] In this embodiment, the failure detection current value Ib is a current value smaller than the magnetic gear out-of-synchronization current value Ig. According to this, it is possible to reliably detect that the first expansion valve 113 has failed before the magnetic gear 60b gets out of synchronization.

[0125] In this embodiment, the current value Ia during the opening degree adjustment, the failure detection current value Ib, the fully closed limit current value Is, and the magnetic gear out-of-synchronization current value Ig satisfy the relationship Ia < Ib < Is < Ig. According to this, it is possible to reliably determine that an abnormality has occurred in the operation of the valve body 48 before the magnetic gear 60b gets out of synchronization, and it is possible to reliably suppress the magnetic gear 60b from getting out of synchronization during the fully closed operation.

[0126] In this embodiment, the first expansion valve control device 81 does not perform failure detection control during full-closed operation. According to this, it is possible to avoid erroneously detecting that the first expansion valve 113 has failed when the valve body 48 closes the valve port 52a.

[0127] In this embodiment, the full-closed limit current value Is is the motor current value when the motor unit 11 becomes non-rotatable. According to this, it is possible to reliably suppress the magnetic gear 60b from being out of synchronization during full-closed operation.

[0128] (Second Embodiment) In the above first embodiment, the current value Ia during opening degree adjustment, the failure detection current value Ib, the motor base speed current value Iv, the full-closed limit current value Is, and the magnetic gear out-of-synchronization current value Ig are in the relationship of Ia < Ib < Iv < Is < Ig.

[0129] In this embodiment, as shown in FIG. 8, the current value Ia during opening degree adjustment, the failure detection current value Ib, the motor base speed current value Iv, the full-closed limit current value Is, and the magnetic gear out-of-synchronization current value Ig are in the relationship of Ia < Ib < Is < Iv < Ig.

[0130] According to this, since it can rotate at the base speed even when the valve is shut, compared with the above first embodiment in which it rotates at a speed slower than the base speed when the valve is shut, the time until shut can be shortened.

[0131] (Third Embodiment) In the above first embodiment, the current value Ia during opening degree adjustment, the failure detection current value Ib, the motor base speed current value Iv, the full-closed limit current value Is, and the magnetic gear out-of-synchronization current value Ig are in the relationship of Ia < Ib < Iv < Is < Ig.

[0132] In this embodiment, as shown in FIG. 9, the current value Ia during opening degree adjustment, the failure detection current value Ib, the motor base speed current value Iv, the full-closed limit current value Is, and the magnetic gear out-of-synchronization current value Ig are in the relationship of Ia < Iv < Ib < Is < Ig.

[0133] As a result, the fault detection torque value Tb becomes larger compared to the first embodiment, so that the flow rate adjustment operation can be performed with a larger torque compared to the first embodiment.

[0134] (Fourth Embodiment) In the first embodiment, the current value Ia during opening degree adjustment, the fault detection current value Ib, the motor base speed current value Iv, the fully closed time limit current value Is, and the magnetic gear out-of-tune current value Ig have the relationship of Ia < Ib < Iv < Is < Ig.

[0135] In this embodiment, as shown in FIG. 10, the current value Ia during opening degree adjustment, the fault detection current value Ib, the motor base speed current value Iv, the fully closed time limit current value Is, and the magnetic gear out-of-tune current value Ig have the relationship of Ia < Iv < Ib = Is < Ig.

[0136] Thereby, the control can be simplified as compared with the case where the fault detection torque value Tb and the fully closed time limit torque value Ts are different from each other.

[0137] (Fifth Embodiment) In the fault detection control of the first embodiment, when the current of the motor unit 11 reaches the fault detection current value Ib, it is determined that the first expansion valve 113 has failed. However, in the fault detection control of this embodiment, when the current of the motor unit 11 reaches the fault detection current value Ib and the motor unit 11 is not rotating, it is determined that the first expansion valve 113 has failed.

[0138] FIG. 11 is a flowchart showing the control process executed by the first expansion valve control device 81 of this embodiment. In step S2000, an instruction signal of the operation mode is input from the air conditioning control device 80. In step S2010, it is determined whether or not the operation mode instructed by the air conditioning control device 80 is the fully closed operation mode. If it is determined that it is not the fully closed operation mode (that is, it is the opening degree adjustment mode), the process proceeds to step S2020.

[0139] In step S2020, a command signal for the target opening is input from the air conditioning control device 80. In step S2030, the fault detection current value Ib stored in advance in the air conditioning control device 80 is read out. In step S2040, the motor unit 11 is feedback-controlled so that the rotational position of the motor unit 11 approaches the target position.

[0140] In step S2050, it is determined whether the motor current has reached the failure detection current value Ib based on the detection signal of the first current / voltage sensor 90. If it is determined in step S2050 that the motor current has reached the failure detection current value Ib, the process proceeds to step S2060.

[0141] In step S2060, it is determined whether or not the motor unit 11 is rotating based on the detection signal of the first rotation angle sensor 91. If it is determined in step S2060 that the motor unit 11 is not rotating, the process proceeds to step S2070, and a signal indicating expansion valve failure is sent to the air conditioning control device 80.

[0142] That is, it is considered that interference from a foreign object or the like not only caused the motor current to exceed the opening adjustment current value Ia, but also prevented the motor unit 11 from rotating, and therefore it is estimated that the first expansion valve 113 has failed.

[0143] If it is determined in step S2050 that the motor current has not reached the fault detection current value Ib, the process proceeds to step S2080. Also, if it is determined in step S2060 that the motor unit 11 is rotating, the process proceeds to step S2080.

[0144] In step S2080, it is determined whether or not the rotational position of the motor unit 11 has reached the target position, based on the detection signal of the first rotation angle sensor 91. If it is determined that the rotational position of the motor unit 11 has not reached the target position, the process returns to step S2040.

[0145] If it is determined in step S2080 that the rotational position of the motor unit 11 has reached the target position, the process proceeds to step S2090, in which a signal indicating that the motor unit 11 has reached the target position is output to the air conditioning control device 80.

[0146] On the other hand, if it is determined in step S2010 that the operating mode instructed by the air conditioning control device 80 is the fully closed operating mode, the process proceeds to step S2100, where the fully closed limit current value Is stored in advance in the air conditioning control device 80 is read out.

[0147] In step S2110, the motor unit 11 is feedback-controlled so that the rotational position of the motor unit 11 approaches the target position (the position at which the valve element 48 is fully closed). In step S2120, it is determined whether the motor current has reached the fully closed limit current value Is based on the detection signal of the first current / voltage sensor 90. If it is determined in step S2120 that the motor current has not reached the fully closed limit current value Is, the process returns to step S2110.

[0148] If it is determined in step S2120 that the motor current has reached the fully closed limit current value Is, the process proceeds to step S2130, in which a signal indicating that the valve has been closed is output to the air conditioning controller 80.

[0149] As a result, similarly to the first embodiment, a failure of the first expansion valve 113 can be detected when adjusting the opening degree, and the valve port 52a can be reliably fully closed when performing a full closing operation.

[0150] In this embodiment, during failure detection control, the first expansion valve control device 81 determines that the first expansion valve 113 has failed when the motor current reaches the failure detection current value Ib and the motor unit 11 becomes unable to rotate.

[0151] This makes it possible to reliably detect that the first expansion valve 113 has failed before the magnetic gear 60b loses synchronization.

[0152] (Sixth embodiment) In the failure detection control of the first embodiment described above, if the current of the motor unit 11 reaches the failure detection current value Ib, it is determined that the first expansion valve 113 has failed. However, in the failure detection control of this embodiment, if the motor unit 11 does not reach the target position within a predetermined time, it is determined that the first expansion valve 113 has failed.

[0153] 12 is a flowchart showing the control process executed by the first expansion valve control device 81 of this embodiment. In step S3000, an operation mode instruction signal is input from the air conditioning control device 80. In step S3010, it is determined whether the operation mode instructed by the air conditioning control device 80 is the fully closed operation mode, and if it is determined that it is not the fully closed operation mode (i.e., the opening adjustment mode), the process proceeds to step S3020.

[0154] In step S3020, a command signal for the target opening degree is input from the air conditioning control device 80. In step S3030, the failure detection current value Ib stored in advance in the air conditioning control device 80 is read out.

[0155] In step S3040, feedback control is performed on motor unit 11 so that the rotational position of motor unit 11 approaches the target position. In step S3050, it is determined whether a predetermined time has elapsed since motor unit 11 started to rotate. If it is determined that the predetermined time has not elapsed since motor unit 11 started to rotate, the process returns to step S3040.

[0156] If it is determined in step S3050 that a predetermined time has elapsed since the motor unit 11 started to rotate, the process proceeds to step S3060, where it is determined based on the detection signal of the first rotation angle sensor 91 whether the rotation position of the motor unit 11 has reached the target position within the predetermined time.

[0157] If it is determined in step S3060 that the rotational position of the motor unit 11 has reached the target position, the process proceeds to step S3070, where a signal indicating that the motor unit 11 has reached the target position is output to the air conditioning control device 80.

[0158] If it is determined in step S3060 that the rotational position of the motor unit 11 has not reached the target position within the predetermined time, the process proceeds to step S3080, in which a signal indicating a failure of the expansion valve is sent to the air conditioning control device 80.

[0159] That is, it is considered that the rotational position of the motor unit 11 is prevented from reaching the target position due to interference from a foreign object or the like, and therefore it is estimated that the first expansion valve 113 has failed.

[0160] On the other hand, if it is determined in step S3010 that the operation mode instructed by the air conditioning control device 80 is the fully closed operation mode, the process proceeds to step S3100, where the fully closed limit current value Is is read out from the memory in advance in the air conditioning control device 80. In step S3110, the motor unit 11 is feedback-controlled so that the rotational position of the motor unit 11 approaches the target position (the position where the valve element 48 is fully closed). In step S3120, it is determined whether the motor current has reached the fully closed limit current value Is based on the detection signal of the first current / voltage sensor 90. If it is determined in step S3120 that the motor current has not reached the fully closed limit current value Is, the process returns to step S3110.

[0161] If it is determined in step S3120 that the motor current has reached the fully closed limit current value Is, the process proceeds to step S3130, in which a signal indicating that the valve has been closed is output to the air conditioning controller 80.

[0162] As a result, similarly to the first embodiment, a failure of the first expansion valve 113 can be detected when adjusting the opening degree, and the valve port 52a can be reliably fully closed when performing a full closing operation.

[0163] In this embodiment, the first expansion valve control device 81 determines that the first expansion valve 113 has failed when the motor current reaches the failure detection current value Ib and the motor unit 11 does not reach the target rotation position within a predetermined time during failure detection control. The failure detection current value Ib is a current value that is greater than the opening adjustment current value Ia and smaller than the fully closed limit current value Is.

[0164] This makes it possible to reliably detect that the first expansion valve 113 has failed before the magnetic gear 60b loses synchronization.

[0165] The present disclosure is not limited to the above-described embodiments, and various modifications can be made as follows within the scope of the present disclosure.

[0166] In the above embodiment, an example is shown in which the present disclosure is applied to an expansion valve of a vapor compression refrigeration cycle, but the present disclosure is not limited to expansion valves and can be applied to various electric valves that open and close a valve port through which a fluid passes using a valve body.

[0167] Although the present disclosure has been described with reference to the embodiments, it is understood that the present disclosure is not limited to the embodiments or structures. The present disclosure also encompasses various modifications and equivalent modifications. In addition, various combinations and forms, including only one element, more than one element, or less than one element, are also within the scope and spirit of the present disclosure.

[0168] The motor-operated valve disclosed in this specification has the following features:

[0169] (Item 1) a motor unit (11) that generates a rotational driving force when supplied with electric power; a valve opening forming member (50) that forms a valve opening (52a) through which a fluid passes; a valve body (48) that opens and closes the valve port; a magnetic gear (60b) that magnetically transmits the rotational driving force from the output shaft (14) of the motor unit to the valve element; a control unit (81) that controls a current supplied to the motor unit, the control unit limits the current supplied to the motor unit to a fully closed limit current value (Is) or less during a fully closed operation in which the valve body fully closes the valve port, The fully closed limit current value is an electric valve having a current value greater than the opening adjustment current value (Ia), which is the value of the current supplied to the motor unit during opening adjustment when the valve body adjusts the opening of the valve port.

[0170] (Item 2) 2. The motor-operated valve according to item 1, wherein the fully closed limit current value is a current value smaller than a magnetic gear out-of-step current value (Ig) that is a current value when the magnetic gear steps out of step.

[0171] (Item 3) the control unit performs abnormality determination control to determine that an abnormality has occurred in the operation of the valve body when the current supplied to the motor unit reaches an abnormality determination current value (Ib); 3. The motor-operated valve according to item 1 or 2, wherein the abnormality determination current value is a current value that is greater than the opening adjustment current value and smaller than the fully closed limit current value.

[0172] (Item 4) the control unit performs abnormality determination control to determine that an abnormality has occurred in the operation of the valve body when the current supplied to the motor unit reaches an abnormality determination current value (Ib) and the motor unit becomes unable to rotate; 3. The motor-operated valve according to item 1 or 2, wherein the abnormality determination current value is a current value that is greater than the opening adjustment current value and smaller than the fully closed limit current value.

[0173] (Item 5) the control unit performs abnormality determination control to determine that an abnormality has occurred in the operation of the valve body when the current supplied to the motor unit reaches an abnormality determination current value (Ib) and the motor unit does not reach a target rotation position within a predetermined time; 3. The motor-operated valve according to item 1 or 2, wherein the abnormality determination current value is a current value that is greater than the opening adjustment current value and smaller than the fully closed limit current value.

[0174] (Item 6) The electric valve according to any one of Items 3 to 5, wherein the abnormal determination current value is a current value smaller than a magnetic gear demagnetization current value (Ig) which is a current at which the magnetic gear becomes out of tune.

[0175] (Item 7) The electric valve according to Item 6, wherein when the current value during opening degree adjustment is Ia, the abnormal determination current value is Ib, the full-closed time limit current value is Is, and the magnetic gear demagnetization current value is Ig, the relationship Ia < Ib < Is < Ig holds.

[0176] (Item 8) The electric valve according to Item 7, wherein the control unit does not perform the abnormal determination control during the full-closed operation.

[0177] (Item 9) The control unit feedback-controls the current supplied to the motor unit based on the rotational position of the motor unit. The electric valve according to any one of Items 1 to 8, wherein the full-closed time limit current value is a current value supplied to the motor unit when the motor unit becomes non-rotatable.

Claims

1. a motor unit (11) that generates a rotational driving force when supplied with electric power; a valve opening forming member (50) that forms a valve opening (52a) through which a fluid passes; a valve body (48) for opening and closing the valve port; a magnetic gear (60b) that magnetically transmits the rotational driving force from the output shaft (14) of the motor unit to the valve body; a control unit (81) that controls a current supplied to the motor unit, the control unit limits the current supplied to the motor unit to a fully closed limit current value (Is) or less during a fully closed operation in which the valve body fully closes the valve port, The fully closed limit current value is an electric valve having a current value greater than the opening adjustment current value (Ia), which is the value of the current supplied to the motor unit during opening adjustment when the valve body adjusts the opening of the valve port.

2. 2. The motor-operated valve according to claim 1, wherein the fully closed limit current value is a current value smaller than a magnetic gear out-of-step current value (Ig) that is a current value when the magnetic gear steps out of step.

3. the control unit performs abnormality determination control to determine that an abnormality has occurred in the operation of the valve body when the current supplied to the motor unit reaches an abnormality determination current value (Ib); 2. The motor-operated valve according to claim 1, wherein the abnormality determination current value is a current value that is greater than the opening adjustment current value and smaller than the fully closed limit current value.

4. the control unit performs abnormality determination control to determine that an abnormality has occurred in the operation of the valve body when the current supplied to the motor unit reaches an abnormality determination current value (Ib) and the motor unit becomes unable to rotate, 2. The motor-operated valve according to claim 1, wherein the abnormality determination current value is a current value that is greater than the opening adjustment current value and smaller than the fully closed limit current value.

5. the control unit performs abnormality determination control to determine that an abnormality has occurred in the operation of the valve body when the current supplied to the motor unit reaches an abnormality determination current value (Ib) and the motor unit does not reach a target rotation position within a predetermined time; 2. The motor-operated valve according to claim 1, wherein the abnormality determination current value is a current value that is greater than the opening adjustment current value and smaller than the fully closed limit current value.

6. 6. The motor-operated valve according to claim 3, wherein the abnormality determination current value is a current value smaller than a magnetic gear out-of-step current value (Ig) at which the magnetic gear loses synchronization.

7. The electric valve according to claim 6, wherein the relationship Ia<Ib<Is<Ig is satisfied, where Ia is the current value during opening adjustment, Ib is the abnormality determination current value, Is is the limit current value when fully closed, and Ig is the magnetic gear detuning current value.

8. The motor-operated valve according to claim 7, wherein the control unit does not perform the abnormality determination control during the fully closed operation.

9. the control unit performs feedback control of the current supplied to the motor unit based on the rotational position of the motor unit; 6. The motor-operated valve according to claim 1, wherein the fully closed state limit current value is a current value supplied to the motor unit when the motor unit is unable to rotate.

Images