Electric valve and electric valve device

Abstract

[Problem] To provide an electrically operated valve and an electrically operated valve device capable of detecting the rotation direction of a stepping motor. [Solution] A magnetic rotor (31) of an electrically operated valve (5) has a drive rotor (311) and a detection rotor (312) coaxially connected to the drive rotor (311). The detection rotor (312) has a cylindrical outer peripheral surface on which a plurality of detection magnetic poles (dp1-dp6) are arranged in the circumferential direction. A magnetic sensor (91) of an electric valve (5) detects the magnetic field of a plurality of detection magnetic poles (dp1-dp6). At least three of the plurality of detection magnetic poles (dp1-dp6) have different circumferential lengths from each other.

Description

Technical Field

[0001] The present invention relates to an electric valve and an electric valve device having the electric valve and an electric valve control device. Background Art

[0002] Patent Document 1 discloses an example of a conventional electric valve. The electric valve is assembled into, for example, an air conditioning system. The electric valve has a housing, a rotor, a stator, and one Hall IC. The rotor is disposed inside the housing. The rotor has a drive rotor and a detection rotor. The stator is disposed outside the housing. The rotor and the stator constitute a stepping motor. The Hall IC is disposed outside the housing. The output signal of the Hall IC is a signal (binary signal) corresponding to the orientation of the magnetic field generated by the detection rotor.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2003-329698

[0006] Technical Problem to be Solved by the Invention

[0007] The electric valve is controlled by an air conditioning control device. The air conditioning control device inputs pulses to the stepping motor to rotate the rotor. On the outer peripheral surface of the detection rotor, N poles and S poles are arranged at equal intervals in the circumferential direction. Regardless of the direction in which the rotor rotates, the output signal of the Hall IC changes at a constant period. Therefore, the air conditioning control device cannot detect the rotation direction of the rotor based on the output signal of the Hall IC and cannot determine whether the rotor is rotating in the correct direction. Summary of the Invention

[0008] Accordingly, an object of the present invention is to provide an electric valve and an electric valve device capable of detecting the rotation direction of a stepping motor.

[0009] Technical Means for Solving the Technical Problem

[0010] To achieve the above object, an electric valve according to an aspect of the present invention includes: a valve body having a valve port; a stepping motor having a drive rotor and a stator; a valve element that moves relative to the valve port according to the rotation of the drive rotor; a detection rotor coaxially connected to the drive rotor; and a magnetic sensor, wherein the detection rotor has a cylindrical outer peripheral surface on which a plurality of detection magnetic poles are arranged in the circumferential direction, the magnetic sensor detects the magnetic fields of the plurality of detection magnetic poles, and the circumferential lengths of at least three of the plurality of detection magnetic poles are different from each other.

[0011] According to the present invention, when the detection rotor rotates together with the drive rotor, the magnetic fields of a plurality of detection magnetic poles are sequentially detected by a magnetic sensor. The output signal of the magnetic sensor contains signal portions corresponding to at least three detection magnetic poles having different circumferential lengths. The order of appearance of these signal portions when the detection rotor rotates in the first direction is different from the order of appearance of these signal portions when the detection rotor rotates in the second direction. Therefore, based on the output signal of the magnetic sensor, the rotation direction of the drive rotor can be detected.

[0012] In the present invention, preferably, the plurality of detection magnetic poles are arranged in the circumferential direction such that the polarities alternate on the outer circumferential surface of the detection rotor, and at least one of the plurality of detection magnetic poles has a different polarity and circumferential length.

[0013] According to the present invention, when the detection rotor rotates together with the drive rotor, the magnetic fields of a plurality of detection magnetic poles are sequentially detected by a magnetic sensor. The output signal of the magnetic sensor contains signal portions corresponding to the plurality of detection magnetic poles. At least one of the plurality of detection magnetic poles has a different polarity and circumferential length, so at least one of the signal values and lengths of these signal portions is different. The order of appearance of these signal portions when the detection rotor rotates in the first direction is different from the order of appearance of these signal portions when the detection rotor rotates in the second direction. Therefore, based on the output signal of the magnetic sensor, the rotation direction of the drive rotor can be detected.

[0014] In addition, the positions (angles) of the boundaries of a plurality of detection magnetic poles (N poles, S poles) are determined in advance on the outer circumferential surface of the detection rotor. When the detection rotor rotates and this boundary passes through the detection region of the magnetic sensor, the output signal changes from a first signal value to a second signal value, or from the second signal value to the first signal value. In a structure where the magnetic sensor outputs a binary signal corresponding to the orientation of the magnetic field, for example, the first signal value is "H" and the second signal value is "L". In a structure where the magnetic sensor outputs an analog signal corresponding to the orientation of the magnetic field, for example, the first signal value is a positive value and the second signal value is a negative value. Therefore, based on the output signal of the magnetic sensor, the rotation angle of the drive rotor can be obtained.

[0015] In the present invention, preferably, the plurality of detection magnetic poles are arranged in the order of the circumferential length from large to small. By doing so, the length of the signal portion corresponding to the detection magnetic pole in the output signal of the magnetic sensor gradually becomes longer or gradually becomes shorter according to the rotation direction of the detection rotor. Therefore, based on the output signal of the magnetic sensor, the rotation direction of the drive rotor can be detected more easily.

[0016] In the present invention, preferably, the electric valve further has a stop mechanism that restricts the rotation of the drive rotor in the first direction when the drive rotor is in the reference position. When the drive rotor is in the reference position, the magnetic sensor detects the magnetic field of one detection magnetic pole among the plurality of detection magnetic poles. Hereinafter, this one detection magnetic pole will be referred to as the reference detection magnetic pole. By doing so, when the rotation of the drive rotor in the first direction is restricted at the reference position, the output of the signal portion corresponding to the reference detection magnetic pole in the output signal of the magnetic sensor is not completed. Thus, when the output signal of the magnetic sensor does not contain the signal portion corresponding to the reference detection magnetic pole, it can be inferred that the drive rotor is in the reference position. Therefore, based on the output signal of the magnetic sensor, it can be detected that the drive rotor is in the reference position.

[0017] In the present invention, preferably, the reference detection magnetic pole is the detection magnetic pole having the smallest circumferential length among the plurality of detection magnetic poles. By doing so, it is possible to determine earlier whether the output of the signal portion corresponding to the reference detection magnetic pole in the output signal of the magnetic sensor is completed. Therefore, based on the output signal of the magnetic sensor, it is possible to detect earlier that the drive rotor is in the reference position.

[0018] In the present invention, preferably, the drive rotor has a cylindrical outer peripheral surface and a plurality of drive magnetic poles. The plurality of drive magnetic poles are circumferentially arranged in such a manner that the polarities alternate on the outer peripheral surface of the drive rotor, and each has the same circumferential length. The circumferential length of the reference detection magnetic pole is equal to or less than the circumferential length of the drive magnetic poles, and a straight line passing through the circumferential center of the reference detection magnetic pole passes through the circumferential center of one of the plurality of drive magnetic poles. By doing so, it is possible to determine earlier whether the output of the signal portion corresponding to the reference detection magnetic pole in the output signal of the magnetic sensor is completed. Therefore, based on the output signal of the magnetic sensor, it is possible to detect earlier that the drive rotor is in the reference position.

[0019] In the present invention, preferably, the central angle corresponding to the circumferential length of the reference detection magnetic pole is smaller than twice the step angle of the stepping motor. By doing so, the signal portion corresponding to the reference detection magnetic pole in the output signal of the magnetic sensor has a length corresponding to approximately one pulse, and it is possible to determine earlier whether the output of the signal portion corresponding to the reference detection magnetic pole in the output signal of the magnetic sensor is completed. Therefore, based on the output signal of the magnetic sensor, it is possible to detect earlier that the drive rotor is in the reference position.

[0020] In order to achieve the above object, another aspect of the present invention relates to an electric valve device having the electric valve and an electric valve control device for controlling the electric valve. Among them, the electric valve control device obtains the rotation direction of the drive rotor based on the output signal of the magnetic sensor. According to the present invention, the electric valve control device can detect the rotation direction of the drive rotor of the electric valve through simple control.

[0021] In the present invention, preferably, the electric valve control device inputs pulses to the stepping motor to rotate the drive rotor, and the electric valve control device detects the misalignment of the stepping motor according to the rotation angle of the drive rotor obtained based on the output signal of the magnetic sensor and the rotation angle of the drive rotor corresponding to the pulses input to the stepping motor. In this way, the electric valve control device can detect the misalignment of the stepping motor through simple control.

[0022] In order to achieve the above object, another aspect of the present invention relates to an electric valve device having the electric valve and an electric valve control device for controlling the electric valve. Among them, in the operation of the electric valve control device positioning the drive rotor at the reference position, pulses are input to the stepping motor to rotate the drive rotor in the first direction, and when the output signal of the magnetic sensor does not contain a signal portion corresponding to the reference detection magnetic pole, the input of pulses to the stepping motor is stopped. According to the present invention, the electric valve control device can easily control the stepping motor to stop after positioning the drive rotor at the reference position.

[0023] Effects of the Invention

[0024] According to the present invention, the rotation direction of the stepping motor can be detected by a simple structure. Brief Description of the Drawings

[0025] Figure 1 It is a block diagram of an air conditioning system having an electric valve device according to an embodiment of the present invention.

[0026] Figure 2 It is a cross-sectional view of the electric valve device.

[0027] Figure 3 It is a perspective view of the magnetic rotor.

[0028] Figure 4 It is a bottom view and a top view of the magnetic rotor.

[0029] Figure 5 It is a view showing the outer peripheral surface of the magnetic rotor developed into a planar shape.

[0030] Figure 6 It is a cross-sectional view of the stator unit.

[0031] Figure 7 It is a perspective view of a sensor substrate and a substrate support member.

[0032] Figure 8 It is another perspective view of a sensor substrate and a substrate support member.

[0033] Figure 9 It is a diagram for explaining the configuration of a magnetic sensor.

[0034] Figure 10 It is a diagram schematically showing the positional relationship between the pole teeth of a stator and a magnetic sensor.

[0035] Figure 11 It is a perspective view of a control substrate.

[0036] Figure 12 It is a diagram showing the connection relationship among a microcomputer, a stepping motor, and a magnetic sensor.

[0037] Figure 13 It is a diagram showing an example of the relationship between a pulse and a drive current.

[0038] Figure 14 It is a diagram schematically showing the positional relationship between a magnetic rotor and a stator (when input pulse P[1] is applied).

[0039] Figure 15 It is a diagram schematically showing the positional relationship between a magnetic rotor and a stator (when input pulse P[2] is applied).

[0040] Figure 16 It is a diagram schematically showing the positional relationship between a magnetic rotor and a stator (when input pulse P[3] is applied).

[0041] Figure 17 It is a diagram schematically showing the positional relationship between a magnetic rotor and a stator (when input pulse P[4] is applied).

[0042] Figure 18 It is a diagram schematically showing the positional relationship between a magnetic rotor and a stator (when input pulse P[5] is applied).

[0043] Figure 19 It is a diagram schematically showing the positional relationship between a magnetic rotor and a stator (when input pulse P[6] is applied).

[0044] Figure 20 It is a diagram schematically showing the positional relationship between a magnetic rotor and a stator (when input pulse P[7] is applied).

[0045] Figure 21 It is a diagram schematically showing the positional relationship between a magnetic rotor and a stator (when input pulse P[8] is applied).

[0046] Figure 22 It is a diagram showing an example of the output signal of a magnetic sensor.

[0047] Figure 23 It is a diagram showing an example of the relationship between the time, the pulses input to the stepping motor, the rotation direction and rotation angle of the magnetic rotor, and the output signal of the magnetic sensor.

[0048] Figure 24 It is a diagram illustrating the movement of the magnetic rotor in a state where the rotation of the magnetic rotor in the first direction is restricted.

[0049] Figure 25 It is a diagram illustrating the movement of the magnetic rotor in a state where the rotation of the magnetic rotor in the first direction is restricted (continued Figure 24 ).

[0050] Figure 26 It is a flowchart showing an example of the operation of the electric valve control device.

[0051] Figure 27 It is a bottom view and a top view showing the structure of the first modified example of the magnetic rotor.

[0052] Figure 28 It is a bottom view and a top view showing the structure of the second modified example of the magnetic rotor. Detailed implementation mode

[0053] Hereinafter, with reference to Figures 1 to 26 , the electric valve device according to an embodiment of the present invention will be described.

[0054] Figure 1 It is a block diagram of an air-conditioning system having the electric valve device according to an embodiment of the present invention. Figure 2 It is a cross-sectional view of an electric valve device having an electric valve and an electric valve control device. Figure 3 It is a perspective view of the magnetic rotor of the electric valve. Figure 4 (A) of is a bottom view of the magnetic rotor. Figure 4 (B) of is a top view of the magnetic rotor. Figure 5 It is a diagram in which the outer peripheral surface of the magnetic rotor is developed into a planar shape. In Figure 4 (A) of , Figure 4 (B) of , and Figure 5 of , the magnetic poles of the drive rotor and the magnetic poles of the detection rotor of the magnetic rotor are schematically shown. Figure 6 It is a cross-sectional view of the stator unit of the electric valve. Figure 7 It is a perspective view of the sensor substrate and the substrate support member of the electric valve. Figure 8 It is another perspective view of the sensor substrate and the substrate support member. Figure 9 It is a diagram illustrating the arrangement of the magnetic sensors of the electric valve. Figure 10 It is a diagram schematically showing the positional relationship between the pole teeth of the stator and the magnetic sensors. Figure 11It is a perspective view of a control board of an electric valve control device. Figure 12 It is a diagram schematically showing the connection relationship among a microcomputer of the electric valve control device, a stepping motor of the electric valve, and a magnetic sensor. Figure 13 It is a diagram showing an example of the relationship between a pulse and a drive current supplied to stators (A-phase stator, B-phase stator). Figures 14 to 21 It is a diagram schematically showing the positional relationship between a magnetic rotor and a stator. Figures 14 to 21 It corresponds to when pulses P[1] to P[8] are input to the stepping motor. Figure 22 (A) of it is a diagram showing an example of an output signal of the magnetic sensor when the magnetic rotor rotates in the first direction. Figure 22 (B) of it is a diagram showing an example of an output signal of the magnetic sensor when the magnetic rotor rotates in the second direction. Figure 23 It is a diagram showing an example of the relationship among time, a pulse input to the stepping motor, the rotation direction and rotation angle of the magnetic rotor, and the output signal of the magnetic sensor. Figure 24 and Figure 25 It is a diagram explaining the movement of the magnetic rotor in a state where the rotation of the magnetic rotor in the first direction is restricted. Figure 26 It is a flowchart showing an example of the operation of the electric valve control device. In Figure 2 and Figure 6 , the magnetic sensor is shown by a dotted line. In Figure 2 , Figures 6 to 9 and Figure 11 , in the X direction indicated by arrow X is the left-right direction, in the Y direction indicated by arrow Y is the front-back direction, and in the Z direction indicated by arrow Z is the up-down direction. On the side where the letter "X" is marked in arrow X is the right direction, on the side where the letter "Y" is marked in arrow Y is the front direction, and on the side where the letter "Z" is marked in arrow Z is the up direction.

[0055] The electric valve device 1 according to this embodiment includes an electric valve 5 and an electric valve control device (hereinafter, simply referred to as "control device 100").

[0056] The electric valve device 1 is assembled, for example, into Figure 1 the air conditioning system 400 shown. The air conditioning system 400 includes a compressor 401, a condenser 402, an electric valve device 1 (electric valve 5), and an evaporator 403. The compressor 401, the condenser 402, the electric valve 5, and the evaporator 403 are sequentially connected via a pipe 405. The air conditioning system 400 includes an air conditioning control device 410. The air conditioning control device 410 is communicably connected to the electric valve device 1 (control device 100) via a communication bus 420. The air conditioning control device 410 controls the flow rate of the refrigerant flowing through the pipe 405 using the electric valve device 1.

[0057] As Figure 2As shown, the electric valve 5 includes a valve body 10, a tank body 20, a drive mechanism 30, a valve core 40, a stator unit 50, a sensor substrate 90, and a magnetic sensor 91.

[0058] The valve body 10 is made of a metal such as aluminum alloy. The valve body 10 includes a main body member 11, a support member 12, and a connecting member 13. The main body member 11 has a rectangular parallelepiped shape. The main body member 11 has a mounting hole 11a. The mounting hole 11a is disposed on the upper surface 11b of the main body member 11. The support member 12 has a cylindrical shape. The lower part of the support member 12 is disposed in the mounting hole 11a. The support member 12 is mounted on the main body member 11 by a threaded structure. The upper part of the support member 12 projects from the upper surface 11b of the main body member 11. The support member 12 has a fitting hole 12a. The fitting hole 12a is disposed on the upper surface of the support member 12. The main body member 11 has a valve chamber 14, a flow path 15, a flow path 16, a valve port 17, and a valve seat 18. The flow path 15 is connected to the valve chamber 14. The flow path 16 is connected to the valve chamber 14 via the valve port 17. The valve seat 18 surrounds the valve port 17 in the valve chamber 14. The connecting member 13 has an annular plate shape. The inner peripheral edge of the connecting member 13 is joined to the upper part of the support member 12.

[0059] The tank body 20 is made of a metal such as stainless steel. The tank body 20 has a cylindrical shape. The upper end of the tank body 20 is closed and the lower end is open. The lower end of the tank body 20 is joined to the outer peripheral edge of the connecting member 13. The tank body 20 is a housing.

[0060] The drive mechanism 30 moves the valve core 40 in the vertical direction (axis L direction). The drive mechanism 30 is disposed inside the tank body 20. The drive mechanism 30 includes a magnetic rotor 31, a valve shaft holder 32, and a guide bushing 33.

[0061] Shown in Figures 3 to 5 is the magnetic rotor 31. The magnetic rotor 31 has a cylindrical shape. The outer diameter of the magnetic rotor 31 is slightly smaller than the inner diameter of the tank body 20. The magnetic rotor 31 integrally has a drive rotor 311 and a detection rotor 312.

[0062] The drive rotor 311 has an outer peripheral surface with a cylindrical shape. The drive rotor 311 has a plurality of drive magnetic poles cp. The plurality of drive magnetic poles cp are disposed on the outer peripheral surface of the drive rotor 311. The plurality of drive magnetic poles cp extend in the vertical direction. The plurality of drive magnetic poles cp have a plurality of N poles and a plurality of S poles. The plurality of N poles and the plurality of S poles are alternately arranged at equal intervals in the circumferential direction. In the present embodiment, the drive rotor 311 has 12 N poles and 12 S poles, and the total number of the plurality of drive magnetic poles cp is 24. The circumferential lengths of the plurality of drive magnetic poles cp are the same. The central angle α1 corresponding to the circumferential length of the plurality of drive magnetic poles cp is 15 degrees. The plurality of drive magnetic poles cp are arranged in the circumferential direction such that the polarities alternate on the outer peripheral surface of the drive rotor 311, and each has the same circumferential length.

[0063] The upper end connection of the detection rotor 312 and the drive rotor 311 is detected. The detection rotor 312 can also be connected to the lower end of the drive rotor 311. The detection rotor 312 is coaxially arranged with the drive rotor 311. The detection rotor 312 rotates together with the drive rotor 311. The outer diameter of the detection rotor 312 is the same as the outer diameter of the drive rotor 311. The detection rotor 312 has a cylindrical outer peripheral surface.

[0064] The detection rotor 312 has a plurality of detection magnetic poles dp1 to dp6. The detection magnetic poles dp1 to dp6 are arranged on the outer peripheral surface of the detection rotor 312. The plurality of detection magnetic poles dp1 to dp6 are a plurality of N poles and a plurality of S poles. The detection magnetic poles dp1, dp3, and dp5 are N poles. The detection magnetic poles dp2, dp4, and dp6 are S poles. The detection magnetic poles dp1 to dp6 are arranged in the circumferential direction in such a manner that the polarities alternate on the outer peripheral surface of the detection rotor 312.

[0065] The central angle β1 corresponding to the circumferential length of the detection magnetic pole dp1 is 10 degrees.

[0066] The central angle β2 corresponding to the circumferential length of the detection magnetic pole dp2 is 30 degrees.

[0067] The central angle β3 corresponding to the circumferential length of the detection magnetic pole dp3 is 45 degrees.

[0068] The central angle β4 corresponding to the circumferential length of the detection magnetic pole dp4 is 50 degrees.

[0069] The central angle β5 corresponding to the circumferential length of the detection magnetic pole dp5 is 100 degrees.

[0070] The central angle β6 corresponding to the circumferential length of the detection magnetic pole dp6 is 125 degrees.

[0071] At least one of the polarity and the circumferential length of the detection magnetic poles dp1 to dp6 is different. If the polarities of the detection magnetic poles dp1 to dp6 are different, the circumferential lengths may be the same. If the circumferential lengths of the detection magnetic poles dp1 to dp6 are different, the polarities may be the same.

[0072] The circumferential lengths of the detection magnetic poles dp1, dp3, and dp5 are different from each other. When the circumferential lengths of the detection magnetic poles dp1, dp3, and dp5 are set as B1, B3, and B5, B1 < B3 < B5. The circumferential lengths of the detection magnetic poles dp2, dp4, and dp6 are different from each other. When the circumferential lengths of the detection magnetic poles dp2, dp4, and dp6 are set as B2, B4, and B6, B2 < B4 < B6. In the electric valve 5, B1 < B2 < B3 < B4 < B5 < B6 holds. Among the circumferential lengths of the detection magnetic poles dp1 to dp6, the circumferential length of the detection magnetic pole dp1 is the shortest, and the circumferential length of the detection magnetic pole dp6 is the longest. The detection magnetic pole dp1 is the minimum detection magnetic pole. The detection magnetic pole dp6 is the maximum detection magnetic pole.

[0073] The detection magnetic poles dp1 to dp6 are arranged in the order of the circumferential length size. In Figure 4 (B) of, in the counterclockwise direction (left-handed), they are arranged in the order of the detection magnetic poles dp1, dp2, dp3, dp4, dp5, and dp6. The circumferential lengths of the detection magnetic poles dp1 to dp6 gradually increase as moving forward in the counterclockwise direction. The circumferential lengths of the detection magnetic poles dp1 to dp6 can also gradually increase as moving forward in the clockwise direction.

[0074] In the electric valve 5, the circumferential length of the detection magnetic pole dp1 is smaller than the circumferential length of the drive magnetic pole cp. When the circumferential length of the drive magnetic pole cp is set as A1, B1 < A1 holds. Preferably, B1 ≤ A1 holds. The circumferential length of the detection magnetic pole dp1 can also be larger than the circumferential length of the drive magnetic pole cp. In the electric valve 5, the line E1, which is the line passing through the circumferential center of the detection magnetic pole dp1, passes through the circumferential center of one of the drive magnetic poles cp1 among the multiple drive magnetic poles cp. The line E1 can also deviate from the circumferential center of the drive magnetic pole cp1.

[0075] As Figure 5 shown, in the detection rotor 312, when the circumferential center of the detection magnetic pole dp1 is set as 0 degrees, the boundary between the detection magnetic pole dp1 and the detection magnetic pole dp6 is the position rotated 5 degrees around the axis L, the boundary between the detection magnetic pole dp6 and the detection magnetic pole dp5 is the position rotated 130 degrees around the axis L, the boundary between the detection magnetic pole dp5 and the detection magnetic pole dp4 is the position rotated 230 degrees around the axis L, the boundary between the detection magnetic pole dp4 and the detection magnetic pole dp3 is the position rotated 280 degrees around the axis L, the boundary between the detection magnetic pole dp3 and the detection magnetic pole dp2 is the position rotated 325 degrees around the axis L, and the boundary between the detection magnetic pole dp2 and the detection magnetic pole dp1 is the position rotated 355 degrees around the axis L.

[0076] The valve shaft holder 32 has a cylindrical shape. The upper end of the valve shaft holder 32 is closed and the lower end is open. A support ring 35 is fixed to the upper wall of the valve shaft holder 32. The support ring 35 connects the magnetic rotor 31 and the valve shaft holder 32. The inner peripheral surface of the valve shaft holder 32 is provided with an internal thread 32c.

[0077] The guide bushing 33 integrally includes a base 33a and a support portion 33b. The base 33a has a cylindrical shape. The support portion 33b has a cylindrical shape. The outer diameter of the support portion 33b is smaller than the outer diameter of the base 33a. The support portion 33b is coaxially connected to the upper end of the base 33a. An external thread 33c is provided on the outer peripheral surface of the support portion 33b. The external thread 33c is screwed into the internal thread 32c of the valve shaft retainer 32. The base 33a is pressed into the fitting hole 12a of the support member 12 of the valve body 10. The guide bushing 33 is combined with the valve body 10.

[0078] A movable stopper 32s is fixed to the valve shaft holder 32. A fixed stopper 33s is fixed to the base 33a of the guide bushing 33. When the movable stopper 32s contacts the fixed stopper 33s, the rotation of the valve shaft holder 32 (i.e., the magnetic rotor 31) in the first direction is restricted. The movable stopper 32s and the fixed stopper 33s constitute a stopper mechanism 38. The stopper mechanism 38 restricts the rotation of the magnetic rotor 31 in the first direction.

[0079] The valve core 40 integrally includes a first shaft portion 41, a second shaft portion 42, and a valve portion 43. The first shaft portion 41 has a cylindrical shape. The first shaft portion 41 is arranged inside the guide bushing 33 and inside the support member 12. The lower end of the first shaft portion 41 is arranged in the valve chamber 14. The second shaft portion 42 has a cylindrical shape. The diameter of the second shaft portion 42 is smaller than the diameter of the first shaft portion 41. The second shaft portion 42 is coaxially connected to the upper end of the first shaft portion 41. The second shaft portion 42 is inserted through a hole provided in the upper wall portion of the valve shaft holder 32. The push rod nut 36 for preventing disengagement is mounted on the second shaft portion 42. The valve portion 43 has a truncated cone shape whose diameter gradually decreases from the upper end toward the lower end. The valve portion 43 is coaxially connected to the lower end of the first shaft portion 41. The valve portion 43 is arranged in the valve chamber 14. The valve portion 43 is opposite to the valve port 17 in the up-down direction. The valve portion 43 opens and closes the valve port 17. When the valve portion 43 contacts the valve seat 18, the valve port 17 is closed. When the valve portion 43 leaves the valve seat 18, the valve port 17 is opened. The valve core 40 has a step portion 44. The step portion 44 is a circular annular plane facing upward. The step portion 44 is arranged at the connection portion between the first shaft portion 41 and the second shaft portion 42. A valve closing spring 37 is arranged between the step portion 44 and the upper wall portion of the valve shaft holder 32. The valve closing spring 37 is a compression coil spring. The valve closing spring 37 pushes the valve core 40 downward. The valve core 40 is formed, for example, by cutting a cylindrical workpiece.

[0080] The stator unit 50 includes a stator 60, a housing 70, and a case 80.

[0081] The stator 60 has a cylindrical shape. The stator 60 includes a phase-A stator 61 and a phase-B stator 62.

[0082] The phase-A stator 61 has a plurality of claw-pole type pole teeth 61a, 61b on its inner circumference. The tip of the pole tooth 61a faces downward, and the tip of the pole tooth 61b faces upward. The pole teeth 61a and 61b are alternately arranged at equal intervals in the circumferential direction. In this embodiment, the phase-A stator 61 has 12 pole teeth 61a and 12 pole teeth 61b. The angle between adjacent pole teeth 61a and 61b is 15 degrees. When the coil 61c of the phase-A stator 61 is energized, the pole teeth 61a and 61b become different polarities.

[0083] The phase-B stator 62 has a plurality of claw-pole type pole teeth 62a, 62b on its inner circumference. The tip of the pole tooth 62a faces downward, and the tip of the pole tooth 62b faces upward. The pole teeth 62a and 62b are alternately arranged at equal intervals in the circumferential direction. In this embodiment, the phase-B stator 62 has 12 pole teeth 62a and 12 pole teeth 62b. The angle between adjacent pole teeth 62a and 62b is 15 degrees. When the coil 62c of the phase-B stator 62 is energized, the pole teeth 62a and 62b become different polarities. The phase-B stator 62 has the same (including substantially the same) structure as the phase-A stator 61.

[0084] The phase-A stator 61 and the phase-B stator 62 are coaxially arranged. The phase-A stator 61 and the phase-B stator 62 are in contact with each other. When viewed from the direction of the axis L, the angle between adjacent pole teeth 61a of the phase-A stator 61 and pole teeth 62a of the phase-B stator 62 is 7.5 degrees. This angle is half of the angle between adjacent pole teeth 61a and 61b, and is also half of the angle between adjacent pole teeth 62a and 62b. The coil 61c of the phase-A stator 61 and the coil 62c of the phase-B stator 62 are connected to a plurality of terminals 65.

[0085] The housing 70 is made of synthetic resin. The housing 70 has a cylindrical shape. The housing 70 is formed by injection molding. The housing 70 houses the stator 60. The housing 70 and the stator 60 are integrally formed (insert molding). Alternatively, the stator 60 and the housing 70 may be separately manufactured, and the stator 60 may be inserted into the inside of the housing 70.

[0086] The stator unit 50 has an inner space 74 defined by the inner surface of the housing 70 and the inner peripheral surface of the stator 60. The can body 20 is disposed in the inner space 74. The stator 60 and the magnetic rotor 31 (drive rotor 311) constitute a stepping motor 66. When the stator 60 (coils 61c, 62c) is energized, attractive and repulsive forces act between the drive magnetic poles cp of the drive rotor 311 and the pole teeth 61a, 61b, 62a, 62b of the stator 60, and the drive rotor 311 rotates.

[0087] The housing 70 has a substrate space 75. The substrate space 75 extends in the lateral direction (a direction orthogonal to the axis L). The substrate space 75 is disposed adjacent to the inner space 74. A partition wall 76 is provided between the inner space 74 and the substrate space 75. The partition wall 76 divides the inner space 74 and the substrate space 75. The cross-section (a section orthogonal to the axis L direction) of the partition wall 76 has an arc shape along the outer peripheral surface of the can body 20.

[0088] The housing 80 is made of synthetic resin. The housing 80 has a rectangular parallelepiped box shape. The housing 80 is joined to the housing 70. The space 85 inside the housing 80 is connected to the substrate space 75 through an opening 80a. A connector 83 is provided at the upper part of the housing 80.

[0089] In Figure 7 、 Figure 8 a sensor substrate 90 is shown. The sensor substrate 90 is a printed substrate on which electronic components are mounted. The sensor substrate 90 is housed in the substrate space 75. The sensor substrate 90 is disposed in the lateral direction. The first end portion 90a of the sensor substrate 90 is disposed in the space 85 of the housing 80. The second end portion 90b of the sensor substrate 90 is disposed near the partition wall 76. A substrate support member 95 is mounted on the sensor substrate 90. A boss 87 of the housing 80 is disposed inside the cylindrical portion 97 of the substrate support member 95. The sensor substrate 90 is mounted on the boss 87 via the substrate support member 95. A magnetic sensor 91 is mounted on the sensor substrate 90.

[0090] The magnetic sensor 91 is a Hall IC. The output signal K of the magnetic sensor 91 is a binary signal. The magnetic sensor 91 is disposed at the second end portion 90b of the sensor substrate 90.

[0091] The magnetic sensor 91 is arranged radially with respect to the detection rotor 312 of the magnetic rotor 31 via the can body 20 and the partition wall 76. In other words, the magnetic sensor 91 is disposed to face the detection rotor 312 in the radial direction (lateral direction) via the can body 20 and the partition wall 76. The magnetic sensor 91 detects the magnetic field generated by one of the detection magnetic poles dp1 to dp6 that faces the magnetic sensor 91 in the radial direction. In addition, the magnetic sensor 91 may also be configured to face the detection rotor 312 in the vertical direction.

[0092] The output signal K of the magnetic sensor 91 is a signal corresponding to the orientation of the magnetic field generated by the detected magnetic poles dp1 to dp6 of the detection rotor 312. Specifically, when the magnetic sensor 91 detects the magnetic field of the N pole, it outputs an H signal (first signal value) as the output signal K, and when it detects the magnetic field of the S pole, it outputs an L signal (second signal value) as the output signal K.

[0093] The output signal K of the magnetic sensor 91 can be an analog signal corresponding to the orientation of the magnetic field. The electric valve 5 can have two or more magnetic sensors 91.

[0094] In Figure 9 shows an example of the configuration of the magnetic sensor 91. Figure 9 is a view of the tank body 20, the magnetic rotor 31, the stator 60, the sensor substrate 90, and the magnetic sensor 91 as viewed from above. In Figure 9 the tank body 20 and the magnetic rotor 31 are shown by a cross-section cut by a plane including the upper surface of the stator 60. In Figure 9 the sensor substrate 90 and the magnetic sensor 91 are shown by dashed lines. In Figure 9 the line M1 connects the axis L and the magnetic detection part of the magnetic sensor 91. The line M1 is a straight line orthogonal to the axis L. The line M1 passes through the circumferential center of the pole tooth 61a of the A-phase stator 61 ( Figure 14 ).

[0095] In Figure 10 shows an example of the positional relationship among the A-phase stator 61, the B-phase stator 62, and the magnetic sensor 91 schematically. As Figure 10 shown, when the A-phase stator 61 and the B-phase stator 62 are viewed from the radial direction, the center of the pole tooth 61a of the A-phase stator 61 and the magnetic detection part of the magnetic sensor 91 are arranged on the line L1. The line L1 is a straight line parallel to the axis L. The line L1 is orthogonal to the line M1.

[0096] In the electric valve 5, the central axes of the main body member 11 (valve port 17, valve seat 18), the support member 12, the connecting member 13, the tank body 20, the magnetic rotor 31 (drive rotor 311, detection rotor 312), the valve element 40, and the stator 60 (A-phase stator 61, B-phase stator 62) coincide with the axis L.

[0097] In the electric valve 5, when the magnetic rotor 31 rotates in the first direction, due to the thread feed action of the internal thread 32c of the valve shaft holder 32 and the external thread 33c of the guide bushing 33, the magnetic rotor 31 and the valve shaft holder 32 move downward. The valve shaft holder 32 presses the valve element 40 downward via the valve closing spring 37. The valve element 40 moves downward, and the valve element 40 contacts the valve seat 18. The position of the magnetic rotor 31 at this time is the valve closing position Rc. When the magnetic rotor 31 further rotates in the first direction from this state, the valve closing spring 37 is compressed, and the magnetic rotor 31 and the valve shaft holder 32 move further downward. The valve element 40 does not move downward. Then, when the movable stopper 32s contacts the fixed stopper 33s, the rotation of the magnetic rotor 31 in the first direction is restricted. The position of the magnetic rotor 31 at this time is the reference position Rx.

[0098] In the electric valve 5, when the magnetic rotor 31 rotates in the second direction, due to the thread feed action of the internal thread 32c of the valve shaft holder 32 and the external thread 33c of the guide bushing 33, the magnetic rotor 31 and the valve shaft holder 32 move upward. The valve shaft holder 32 presses the push rod nut 36 upward. The valve element 40 moves upward, and the valve element 40 moves away from the valve seat 18. When the magnetic rotor 31 further rotates in the valve opening direction, the magnetic rotor 31 reaches the fully open position Rz. When the magnetic rotor 31 is located at the fully open position Rz, the valve element 40 is farthest from the valve port 17.

[0099] In addition, the electric valve 5 may also be configured such that when the magnetic rotor 31 is located at the reference position Rx, the valve element 40 moves away from the valve seat 18.

[0100] In the electric valve 5, when the magnetic rotor 31 is located at the reference position Rx, the circumferential center of the detection magnetic pole dp1 is positioned on the line M1, and the detection magnetic pole dp1 and the magnetic sensor 91 are arranged radially with respect to the magnetic rotor 31. The detection magnetic pole dp1 is the reference detection magnetic pole. Alternatively, when the magnetic rotor 31 is located at the reference position Rx, any one of the detection magnetic poles dp2 to dp6 and the magnetic sensor 91 may be arranged radially. The rotation angle of the magnetic rotor 31 when the magnetic rotor 31 is located at the reference position Rx is set to 0 degrees. The rotation angle increases when the magnetic rotor 31 rotates in the second direction and decreases when it rotates in the first direction.

[0101] In addition, in the electric valve 5, when the magnetic rotor 31 is located at the reference position Rx, the drive magnetic pole cp1 and the pole tooth 61a of the A-phase stator 61 are arranged radially with respect to the magnetic rotor 31.

[0102] The control device 100 includes a control board 110 and a microcomputer 120.

[0103] In Figure 11In the figure, it represents the control substrate 110. The control substrate 110 is a printed circuit board on which electronic components are mounted. The control substrate 110 is housed in the space 85 of the housing 80. The control substrate 110 is arranged in the vertical direction. The control substrate 110 is at a right angle to the sensor substrate 90. The control substrate 110 is arranged near the first end 90a of the sensor substrate 90. The control substrate 110 is connected to the sensor substrate 90 via the connection terminal 93. Multiple terminals 65 of the stator 60 are connected to the control substrate 110. The boss 87 of the housing 80 is arranged in the through-hole 112 of the control substrate 110. The control substrate 110 is mounted on the boss 87. A microcomputer 120 is mounted on the control substrate 110.

[0104] As Figure 1 , Figure 12 shown, the microcomputer 120 is, for example, a microcomputer for embedded devices that integrates a CPU 121 as a central processing unit, a non-volatile memory 122, a motor driver 123, a working memory 124, a communication component 125, etc. into one package. The microcomputer 120 is responsible for the control of the electric valve 5. In addition, the non-volatile memory, the working memory, the communication component, and the motor driver may also be separate electronic components externally connected to the microcomputer 120.

[0105] The CPU 121 executes the program stored in the non-volatile memory 122 and functions as various functional parts. The working memory 124 stores variables used in various functional parts. The communication component 125 is connected to the air conditioner control device 410 via the communication bus 420. The motor driver 123 is connected to the stepping motor 66. Specifically, as Figure 12 shown, the motor driver 123 is connected to the coil 61c of the A-phase stator 61 and the coil 62c of the B-phase stator 62. The motor driver 123 supplies a drive current corresponding to the pulse P to the coil 61c and the coil 62c.

[0106] By inputting the pulse P (P[1]~P[8]) to the stepping motor 66, the magnetic rotor 31 rotates. Specifically, by supplying a drive current corresponding to the pulse P to the stator 60 of the stepping motor 66, the magnetic rotor 31 rotates. In this specification, "inputting the pulse P to the stepping motor 66" is synonymous with "supplying a drive current corresponding to the pulse P to the stator 60 of the stepping motor 66". The pulse P is input to the stepping motor 66 repeatedly in ascending or descending order. The pulses P[1]~P[8] are pulses P of one cycle amount, and are multiple pulses P repeatedly input to the stepping motor 66 in a specified order.

[0107] In this embodiment, the excitation mode of the stepping motor 66 is 1-2 phase excitation, and the step angle of the stepping motor 66 is 3.75 degrees. When the magnetic rotor 31 is located at the reference position Rx, the movable stopper 32s contacts the fixed stopper 33s, and the rotation of the magnetic rotor 31 in the first direction is restricted. The number of pulses P (initialization number) required for the magnetic rotor 31 to rotate from the reference position Rx to the fully open position Rz is 500.

[0108] Figure 13 The pulses P[1] to P[8] shown are sequentially input to the stepping motor 66. In Figures 14 to 21 An example of the positional relationship between the magnetic rotor 31 and the stator 60 when the pulses P[1] to P[8] are input is schematically shown. Figure 14 It shows the state where the magnetic rotor 31 is located at the reference position Rx. In Figure 14 the rotation angle of the magnetic rotor 31 is 0 degrees. In Figures 14 to 21 the magnetic poles of the magnetic rotor 31 (drive rotor 311, detection rotor 312) and the pole teeth of the stator 60 are schematically shown. In Figures 14 to 21 in order to easily grasp the positional relationship between the magnetic rotor 31 and the stator 60 (phase A stator 61, phase B stator 62), marks (black circles) are given to the reference pole tooth 61a and the reference magnetic pole (drive magnetic pole cp1) of the magnetic rotor 31.

[0109] When the pulses P are input to the stepping motor 66 in ascending order (in the order of P[1] to P[8]), the magnetic rotor 31 rotates in the second direction (counterclockwise direction in Figures 14 to 21 ).

[0110] When the pulses P are input to the stepping motor 66 in descending order (in the order of P[8] to P[1]), the magnetic rotor 31 rotates in the first direction (clockwise direction in Figures 14 to 21 ).

[0111] When the magnetic rotor 31 rotates in the first and second directions, the magnetic sensor 91 alternately outputs H signals and L signals corresponding to the detection magnetic poles dp1 to dp6. The H signals and L signals corresponding to the detection magnetic poles dp1 to dp6 are the signal portions in the output signal K corresponding to the detection magnetic poles dp1 to dp6. Since at least one of the polarities and the circumferential lengths of the detection magnetic poles dp1 to dp6 is different from each other, at least one of the signal values and the lengths of the signal portions in the output signal K corresponding to the detection magnetic poles dp1 to dp6 is different from each other.

[0112] The magnetic sensor 91 outputs an H signal corresponding to the detection magnetic pole dp1, and the length of the H signal roughly corresponds to 3 pulses P.

[0113] The magnetic sensor 91 outputs an L signal corresponding to the detection magnetic pole dp2, and the length of the L signal roughly corresponds to 8 pulses P.

[0114] The magnetic sensor 91 outputs an H signal corresponding to the detection magnetic pole dp3, and the length of the H signal roughly corresponds to 12 pulses P.

[0115] The magnetic sensor 91 outputs an L signal corresponding to the detection magnetic pole dp4, and the length of the L signal roughly corresponds to 13 pulses P.

[0116] The magnetic sensor 91 outputs an H signal corresponding to the detection magnetic pole dp5, and the length of the H signal roughly corresponds to 27 pulses P.

[0117] The magnetic sensor 91 outputs an L signal corresponding to the detection magnetic pole dp6, and the length of the L signal roughly corresponds to 33 pulses P.

[0118] Figure 22 (A) shows an example of the output signal K of the magnetic sensor 91 when the magnetic rotor 31 rotates at a constant speed in the first direction. In the waveform of the output signal K corresponding to one rotation (360 degrees) of the magnetic rotor 31, the lengths of the H signal and the L signal gradually become longer. This waveform is repeated every time the magnetic rotor 31 rotates once.

[0119] Figure 22 (B) shows an example of the output signal K of the magnetic sensor 91 when the magnetic rotor 31 rotates at a constant speed in the second direction. In the waveform of the output signal K corresponding to one rotation (360 degrees) of the magnetic rotor 31, the lengths of the H signal and the L signal gradually become shorter. This waveform is repeated every time the magnetic rotor 31 rotates once.

[0120] The magnetic sensor 91 outputs an output signal K corresponding to the rotation direction of the detection rotor 312. That is, the waveform of the output signal K when the detection rotor 312 rotates in the first direction is different from the waveform of the output signal K when it rotates in the second direction. Therefore, the control device 100 can detect the rotation direction of the magnetic rotor 31 based on the output signal K of the magnetic sensor 91.

[0121] In addition, the positions (angles) for determining the boundaries of the detected magnetic poles dp1 to dp6 (N poles, S poles) are previously determined in the outer peripheral surface of the rotor 312. When passing through the position where the boundary and the magnetic sensor 91 are arranged in the radial direction, the output signal K changes from the H signal to the L signal, or from the L signal to the H signal. Therefore, the control device 100 can obtain the rotation angle of the magnetic rotor 31 based on the output signal K of the magnetic sensor 91. In particular, the control device 100 can obtain the absolute rotation angle (0 to 360 degrees) of the magnetic rotor 31 at the time of the second change based on the signal value and length of the output signal K from the first change of the output signal K to the second change after the first change. The control device 100 can also use the absolute rotation angle of the magnetic rotor 31 to correct the rotation angle (variable) of the magnetic rotor 31 used in the control.

[0122] Next, referring to Figures 23 to 25 , in the electric valve device 1, the output signal K of the magnetic sensor 91 when the magnetic rotor 31 rotates in the first direction will be described. Figure 23 is a diagram showing an example of the pulse P input to the stepping motor 66 at times T1 to T113, the rotation direction and rotation angle of the magnetic rotor 31, and the output signal K. Figure 24 , Figure 25 is a diagram for explaining the movement of the magnetic rotor 31 in a state where the rotation of the magnetic rotor 31 in the first direction is restricted. In Figure 24 , Figure 25 , in order to easily grasp the positional relationship between the magnetic rotor 31 and the stator 60 (A-phase stator 61, B-phase stator 62), marks (black circles) are given to the reference pole tooth 61a and the drive magnetic pole cp1 (S pole) of the reference drive rotor 311. In Figure 24 , Figure 25 , the right direction is the first direction, and the left direction is the second direction. Figure 24 's (A) to Figure 24 's (D), Figure 25 's (A) to Figure 25 's (D) correspond to Figure 23 's times T105 to T113.

[0123] When the control device 100 repeatedly inputs the pulse P to the stepping motor 66 in descending order at constant time intervals (times T1 to T113), the magnetic rotor 31 rotates step by step in the first direction by the step angle. When the pulse P[1] is input to the stepping motor 66 at time T1, the rotation angle of the magnetic rotor 31 becomes 390 degrees.

[0124] When a pulse P is input to the stepping motor 66 at times T1 to T7 (rotation angle: 390.00 to 367.50 degrees), the magnetic sensor 91 outputs a signal. When a pulse P is input to the stepping motor 66 at time T8, the magnetic rotor 31 rotates in the first direction, and at the time point when the rotation angle of the magnetic rotor 31 becomes 365 degrees, the output signal K switches from the L signal to the H signal.

[0125] When a pulse P is input to the stepping motor 66 at times T8 to T10 (rotation angle: 363.75 to 356.25 degrees), the magnetic sensor 91 outputs an H signal. The H signal at times T8 to T10 corresponds to the detection magnetic pole dp1. When a pulse P is input to the stepping motor 66 at time T11, the magnetic rotor 31 rotates in the first direction, and at the time point when the rotation angle of the magnetic rotor 31 becomes 355 degrees, the output signal K switches from the H signal to the L signal.

[0126] When a pulse P is input to the stepping motor 66 at times T11 to T18 (rotation angle: 352.50 to 326.25 degrees), the magnetic sensor 91 outputs an L signal. The L signal at times T11 to T18 corresponds to the detection magnetic pole dp2. When a pulse P is input to the stepping motor 66 at time T19, the magnetic rotor 31 rotates in the first direction, and at the time point when the rotation angle of the magnetic rotor 31 becomes 325 degrees, the output signal K switches from the L signal to the H signal.

[0127] When a pulse P is input to the stepping motor 66 at times T19 to T30 (rotation angle: 322.50 to 281.25 degrees), the magnetic sensor 91 outputs an H signal. The H signal at times T19 to T30 corresponds to the detection magnetic pole dp3. When a pulse P is input to the stepping motor 66 at time T31, the magnetic rotor 31 rotates in the first direction, and at the time point when the rotation angle of the magnetic rotor 31 becomes 280 degrees, the output signal K switches from the H signal to the L signal.

[0128] When a pulse P is input to the stepping motor 66 at times T31 to T43 (rotation angle: 277.50 to 232.50 degrees), the magnetic sensor 91 outputs an L signal. The L signal at times T31 to T43 corresponds to the detection magnetic pole dp4. When a pulse P is input to the stepping motor 66 at time T44, the magnetic rotor 31 rotates in the first direction, and at the time point when the rotation angle of the magnetic rotor 31 becomes 230 degrees, the output signal K switches from the L signal to the H signal.

[0129] When a pulse P is input to the stepping motor 66 at times T44 to T70 (rotation angle: 228.75 to 131.25 degrees), the magnetic sensor 91 outputs an H signal. The H signal at times T44 to T70 corresponds to the detection magnetic pole dp5. When a pulse P is input to the stepping motor 66 at time T71, the magnetic rotor 31 rotates in the first direction, and at the time point when the rotation angle of the magnetic rotor 31 becomes 130 degrees, the output signal K switches from the H signal to the L signal.

[0130] When a pulse P is input to the stepping motor 66 at times T71 to T103 (rotation angle: 127.50 to 7.50 degrees), the magnetic sensor 91 outputs an L signal. The L signal at times T71 to T103 corresponds to the detection magnetic pole dp6. When a pulse P is input to the stepping motor 66 at time T104, the magnetic rotor 31 rotates in the first direction, and at the time point when the rotation angle of the magnetic rotor 31 becomes 5 degrees, the output signal K switches from the L signal to the H signal.

[0131] Then, when a pulse P[1] is input to the stepping motor 66 at time T105, the magnetic rotor 31 is positioned at the reference position Rx, and the rotation angle of the magnetic rotor 31 is 0 degrees. The magnetic sensor 91 outputs an H signal at time T105. The H signal at time T105 corresponds to the detection magnetic pole dp1. As shown in (A) of Figure 24 When the magnetic rotor 31 is positioned at the reference position Rx, the movable stopper 32s contacts the fixed stopper 33s, and the rotation of the magnetic rotor 31 in the first direction is restricted.

[0132] When pulses P[8], P[7], P[6], and P[5] are input to the stepping motor 66 at times T106, T107, T108, and T109, as shown in (B) of Figure 24 Figure 24 (C) of Figure 24 (D) of Figure 25 (A) of, the magnetic rotor 31 does not rotate. Therefore, after the pulses P are input at times T106, T107, T108, and T109, the rotation angle of the magnetic rotor 31 is 0 degrees, and the magnetic sensor 91 outputs an H signal.

[0133] When a pulse P[4] is input to the stepping motor 66 at time T110, as shown in Figure 25As shown in (B) of , the magnetic rotor 31 rotates in the second direction by an angle three times the step angle. At the time when the rotation angle of the magnetic rotor 31 becomes 5 degrees, the output signal K switches from the H signal to the L signal. The magnetic rotor 31 is positioned at the same position as at time T102 (rotation angle: 11.25 degrees). Time T102 is the time when the pulse P[4] is input before time T110. After the pulse P is input at time T110, the magnetic sensor 91 outputs an L signal. The L signal after time T110 corresponds to the detected magnetic pole dp6.

[0134] When pulses P[3], P[2], and P[1] are input to the stepping motor 66 at times T111, T112, and T113, as Figure 25 shown in (C) of , Figure 25 shown in (D) of , and Figure 24 shown in (A) of , the magnetic rotor 31 rotates step by step in the first direction by the step angle. After the pulse P is input at time T111 (rotation angle: 7.50 degrees), the magnetic sensor 91 outputs an L signal. After the pulse P is input at time T112 (rotation angle: 3.75 degrees), the magnetic sensor 91 outputs an H signal. After the pulse P is input at time T113 (rotation angle: 0.00 degrees), the magnetic sensor 91 outputs an H signal. At the time when the rotation angle of the magnetic rotor 31 becomes 5 degrees during times T111 to T113, the output signal K switches from the L signal to the H signal.

[0135] After that, according to the input of pulses P[8] to P[1], the output signal K repeats the same change as that from time T106 to T113. That is, the magnetic sensors 9 are arranged alternately in the radial direction with the detected magnetic poles dp1 and dp6, and repeatedly output H signals corresponding to approximately 6 pulses P and L signals corresponding to approximately 2 pulses P. The lengths of these H signals and L signals are different from the lengths of any of the signal portions (H signal, L signal) corresponding to the detected magnetic poles dp1 to dp6.

[0136] When the magnetic rotor 31 rotates normally, the output signal K of the magnetic sensor 91 only contains H signals and L signals corresponding to the detected magnetic poles dp1 to dp6. When the rotation of the magnetic rotor 31 in the first direction is restricted, then following the L signal corresponding to the detected magnetic pole dp6 (times T71 to T103), an H signal (times T104 to T109) with a length different from that of the H signal corresponding to the detected magnetic pole dp1 is output. That is, when the rotation of the magnetic rotor 31 in the first direction is restricted, the output of the signal portion corresponding to the detected magnetic pole dp1 is not completed, and the signal portion corresponding to the detected magnetic pole dp1 does not appear in the output signal K. Therefore, the control device 100 can detect that the magnetic rotor 31 is positioned at the reference position Rx by checking whether the output signal K contains the signal portion corresponding to the detected magnetic pole dp1.

[0137] Next, with reference to Figure 26 the flowchart of FIG. 2, an example of the operation of the control device 100 (the operation of positioning the magnetic rotor 31 at the reference position Rx) will be described.

[0138] The control device 100 (specifically, the CPU 121) inputs pulses P to the stepping motor 66 in descending order (S110). The magnetic rotor 31 rotates in the first direction. The control device 100 acquires the output signal K of the magnetic sensor 91 (S120). When the output signal K contains a signal portion corresponding to the detection magnetic pole dp1 (reference detection magnetic pole) (S130: Yes), the control device 100 determines that the magnetic rotor 31 rotates in the first direction and inputs the next pulse P (returns to S110). When the output signal K does not contain a signal portion corresponding to the detection magnetic pole dp1 (S130: No), the control device 100 determines that the magnetic rotor 31 does not rotate and detects that the rotation of the magnetic rotor 31 in the first direction is restricted (S140). Thus, the control device 100 determines that the magnetic rotor 31 is positioned at the reference position Rx and ends the operation.

[0139] The control device 100 can detect that the rotation of the magnetic rotor 31 in the first direction is restricted by the stopper mechanism 38 based on the output signal K of the magnetic sensor 91. In addition, the control device 100 can also detect, for example, that the rotation of the magnetic rotor 31 is restricted by foreign matter mixed in the refrigerant based on the output signal K of the magnetic sensor 91.

[0140] In addition, the control device 100 detects the rotation direction of the magnetic rotor 31 based on the appearance order of the signal portions corresponding to the detection magnetic poles dp1 to dp6 in the output signal K.

[0141] In addition, the control device 100 acquires the rotation angle (actual rotation angle) of the magnetic rotor 31 based on the time point at which the H signal and the L signal in the output signal K are switched. The control device 100 calculates the rotation angle (calculated rotation angle) of the magnetic rotor 31 based on the pulses P input to the stepping motor. The control device 100 detects the misalignment of the stepping motor 66 based on the actual rotation angle and the calculated rotation angle.

[0142] The electric valve device 1 involved in this embodiment has an electric valve 5 and a control device 100. The electric valve 5 has: a valve body 10 having a valve port 17; a stepping motor 66 having a drive rotor 311 and a stator 60; a valve core 40 that moves relative to the valve port 17 according to the rotation of the drive rotor 311; a detection rotor 312 coaxially connected to the drive rotor 311 and having a cylindrical outer peripheral surface; and a single magnetic sensor 91 radially arranged with the detection rotor 312. The output signal K of the magnetic sensor 91 is a binary signal corresponding to the orientation of the magnetic field detected by the magnetic sensor 91. The detection rotor 312 has a plurality of detection magnetic poles dp1 to dp6. The magnetic sensor 91 detects the magnetic fields of the plurality of detection magnetic poles dp1 to dp6. The plurality of detection magnetic poles dp1 to dp6 include a plurality of N poles and a plurality of S poles and are arranged such that the polarities alternate on the outer peripheral surface of the detection rotor 312. The plurality of N poles have different circumferential lengths. The plurality of S poles have different circumferential lengths.

[0143] According to the electric valve 5, when the detection rotor 312 rotates, the plurality of detection magnetic poles dp1 to dp6 are sequentially arranged radially with the magnetic sensor 91. The magnetic fields of the plurality of detection magnetic poles dp1 to dp6 are sequentially detected by the magnetic sensor 91. The output signal K of the magnetic sensor 91 contains signal portions (H signal, L signal) corresponding to the plurality of detection magnetic poles dp1 to dp6. Since at least one of the polarities and circumferential lengths of the plurality of detection magnetic poles dp1 to dp6 is different, at least one of the signal values and lengths of this signal portion is different. The appearance order of this signal portion (i.e., the waveform of the output signal K) when the detection rotor 312 rotates in the first direction is different from the appearance order of this signal portion when the detection rotor 312 rotates in the second direction. Therefore, the rotation direction of the drive rotor 311 can be detected based on the output signal K of a single magnetic sensor 91.

[0144] In addition, the positions (angles) of the boundaries of the detection magnetic poles dp1 to dp6 (N poles, S poles) are determined in advance on the outer peripheral surface of the detection rotor 312. When passing through the position where the boundary is radially arranged with the magnetic sensor 91, the output signal K changes from the H signal to the L signal, or from the L signal to the H signal. Therefore, based on the output signal K of the magnetic sensor 91, the rotation angle of the magnetic rotor 31 can be obtained.

[0145] In addition, the plurality of detection magnetic poles dp1 to dp6 are arranged in the order of the circumferential length size. By doing so, the lengths of the signal portions corresponding to the detection magnetic poles dp1 to dp6 in the output signal K of the magnetic sensor 91 gradually increase or gradually decrease according to the rotation direction of the detection rotor 312. Therefore, based on the output signal K of the magnetic sensor 91, the rotation direction of the drive rotor 311 can be detected more easily.

[0146] In addition, the electric valve 5 has a stop mechanism 38. When the drive rotor 311 is located at the reference position Rx, the stop mechanism 38 restricts the rotation of the drive rotor 311 in the first direction. When the drive rotor 311 is located at the reference position Rx, one of the plurality of detection magnetic poles dp1 to dp6, i.e., the detection magnetic pole dp1 (reference detection magnetic pole), is arranged radially with the magnetic sensor 91, and the magnetic sensor 91 detects the magnetic field of the detection magnetic pole dp1. In this way, when the rotation of the drive rotor 311 in the first direction at the reference position Rx is restricted, the output of the signal portion (H signal) corresponding to the detection magnetic pole dp1 in the output signal K of the magnetic sensor 91 is not completed. Thus, when the output signal K of the magnetic sensor 91 does not contain the signal portion corresponding to the detection magnetic pole dp1, it can be presumed that the drive rotor 311 is located at the reference position Rx. Therefore, based on the output signal K of the magnetic sensor 91, it can be detected that the drive rotor 311 is located at the reference position Rx.

[0147] In addition, the reference detection magnetic pole is the detection magnetic pole dp1 (minimum detection magnetic pole) having the smallest circumferential length among the plurality of detection magnetic poles dp1 to dp6. In this way, it can be determined earlier whether the output of the signal portion corresponding to the detection magnetic pole dp1 in the output signal K of the magnetic sensor 91 is completed. Therefore, based on the output signal K of the magnetic sensor 91, it can be detected earlier that the drive rotor 311 is located at the reference position Rx.

[0148] In addition, the drive rotor 311 has a cylindrical outer peripheral surface and a plurality of drive magnetic poles cp. The plurality of drive magnetic poles cp include a plurality of N poles and a plurality of S poles, and are circumferentially arranged in such a manner that the polarities alternate on the outer peripheral surface of the drive rotor 311. The plurality of drive magnetic poles cp each have the same circumferential length. The circumferential length of the detection magnetic pole dp1 is equal to or less than the circumferential length of the plurality of drive magnetic poles cp. The line E1 passing through the circumferential center of the detection magnetic pole dp1 passes through the circumferential center of one of the plurality of drive magnetic poles cp1. In this way, it can be determined earlier whether the output of the signal portion corresponding to the detection magnetic pole dp1 in the output signal K of the magnetic sensor 91 is completed. Therefore, based on the output signal K of the magnetic sensor 91, it can be detected earlier that the drive rotor 311 is located at the reference position Rx.

[0149] Further, preferably, the central angle β1 corresponding to the circumferential length of the detection magnetic pole dp1 is smaller than twice the step angle of the stepping motor 66. By doing so, the signal portion in the output signal K of the magnetic sensor 91 corresponding to the detection magnetic pole dp1 has a length corresponding to approximately one pulse P, and it is possible to more quickly determine whether the output of the signal portion in the output signal K of the magnetic sensor 91 corresponding to the detection magnetic pole dp1 is completed. Therefore, based on the output signal K of the magnetic sensor 91, it is possible to more quickly detect that the drive rotor 311 is located at the reference position Rx.

[0150] In addition, the control device 100 inputs a pulse P to the stepping motor 66 to rotate the drive rotor 311. The control device 100 obtains the rotation direction of the drive rotor 311 based on the output signal K of the magnetic sensor 91. The control device 100 can detect the rotation direction of the magnetic rotor 31 of the electric valve 5 through simple control.

[0151] In addition, the control device 100 inputs a pulse P to the stepping motor 66 to rotate the drive rotor 311. The control device 100 detects the misalignment of the stepping motor 66 based on the rotation angle of the magnetic rotor 31 obtained from the output signal K of the magnetic sensor 91 and the rotation angle of the magnetic rotor 31 corresponding to the pulse P input to the stepping motor 66. The control device 100 can detect the misalignment of the stepping motor 66 of the electric valve 5 through simple control.

[0152] In addition, in the operation of the control device 100 to position the drive rotor 311 at the reference position Rx, a pulse P is input to the stepping motor 66 to rotate the drive rotor 311 in the first direction. When the signal portion corresponding to the detection magnetic pole dp1 is not included in the output signal K of the magnetic sensor 91, the control device 100 stops inputting the pulse P to the stepping motor 66. The control device 100 can stop the stepping motor 66 through simple control after positioning the drive rotor 311 at the reference position Rx.

[0153] According to the electric valve device 1, in an inexpensive electric valve having only one magnetic sensor 91, it is possible to detect the rotation direction, rotation angle, and misalignment of the stepping motor 66 (magnetic rotor 31).

[0154] In the present embodiment, the electric valve device 1 includes a magnetic rotor 31. Six detection magnetic poles dp1 to dp6 are provided over the entire circumferential surface of the detection rotor 312 of the magnetic rotor 31. The electric valve device 1 may have Figure 27 the magnetic rotor 31A shown or Figure 28 the magnetic rotor 31B shown instead of the magnetic rotor 31.

[0155] Figure 27 Shows the structure of the magnetic rotor 31A, which is a first modification of the magnetic rotor 31 of the electric valve device 1 according to the present embodiment.Figure 27 (A) is a bottom view of the magnetic rotor 31A. Figure 27 (B) is a top view of the magnetic rotor 31A.

[0156] The magnetic rotor 31A integrally has a drive rotor 311 and a detection rotor 312A. The drive rotor 311 of the magnetic rotor 31A has the same structure as the drive rotor 311 of the magnetic rotor 31.

[0157] The detection rotor 312A is connected to the upper end of the drive rotor 311. The detection rotor 312A may also be connected to the lower end of the drive rotor 311. The detection rotor 312A is coaxially arranged with the drive rotor 311. The detection rotor 312A rotates together with the drive rotor 311. The outer diameter of the detection rotor 312A is the same as the outer diameter of the drive rotor 311. The detection rotor 312A has a cylindrical outer peripheral surface.

[0158] The detection rotor 312A has a plurality of detection magnetic poles dp1 to dp3. The detection magnetic poles dp1 to dp3 are arranged on the outer peripheral surface of the detection rotor 312A. The detection magnetic poles dp1 and dp3 are N poles. The detection magnetic pole dp2 is an S pole. The detection magnetic poles dp1 to dp3 are arranged in the circumferential direction in such a manner that the polarities alternate on the outer peripheral surface of the detection rotor 312A. The detection magnetic poles dp1 to dp3 of the detection rotor 312A of the magnetic rotor 31A have the same structure as the detection magnetic poles dp1 to dp3 of the detection rotor 312 of the magnetic rotor 31.

[0159] The detection rotor 312A has a non-magnetized portion NP. The non-magnetized portion NP is arranged between the detection magnetic poles dp1 and dp3 on the outer peripheral surface of the detection rotor 312A. The non-magnetized portion NP is a non-magnetized part of the outer peripheral surface of the detection rotor 312A. No magnetic pole is provided in the non-magnetized portion NP.

[0160] The detection rotor 312A has three detection magnetic poles (detection magnetic poles dp1 to dp3) and one non-magnetized portion NP. The detection magnetic poles dp1 to dp3 and the non-magnetized portion NP are arranged in the circumferential direction on the outer peripheral surface of the detection rotor 312A. The central angle βn corresponding to the circumferential length of the non-magnetized portion NP is 275 degrees.

[0161] Instead of the detection magnetic poles dp4 to dp6, the detection rotor 312A has the same structure as the detection rotor 312 of the magnetic rotor 31 except for having one non-magnetized portion NP.

[0162] When it is detected that the detection rotor 312A rotates together with the drive rotor 311, the magnetic fields of the plurality of detection magnetic poles dp1 to dp3 are sequentially detected by the magnetic sensor 91. The output signal K of the magnetic sensor 91 includes signal portions corresponding to the detection magnetic poles dp1 to dp3 having different circumferential lengths. The appearance order of this signal portion when the detection rotor 312A rotates in the first direction is different from the appearance order of this signal portion when the detection rotor 312A rotates in the second direction. Therefore, the control device 100 can detect the rotation direction of the drive rotor 311 based on the output signal K of the magnetic sensor 91.

[0163] Figure 28 Shows the structure of the magnetic rotor 31B which is a second modification of the magnetic rotor 31 of the electric valve device 1 according to the present embodiment. Figure 28 (A) of is a bottom view of the magnetic rotor 31B. Figure 28 (B) of is a top view of the magnetic rotor 31B.

[0164] The magnetic rotor 31B integrally has a drive rotor 311 and a detection rotor 312B. The drive rotor 311 of the magnetic rotor 31B has the same structure as the drive rotor 311 of the magnetic rotor 31.

[0165] The detection rotor 312B is connected to the upper end of the drive rotor 311. The detection rotor 312B may also be connected to the lower end of the drive rotor 311. The detection rotor 312B is coaxially arranged with the drive rotor 311. The detection rotor 312B rotates together with the drive rotor 311. The outer diameter of the detection rotor 312B is the same as the outer diameter of the drive rotor 311. The detection rotor 312B has a cylindrical outer peripheral surface.

[0166] The detection rotor 312B has a plurality of detection magnetic poles dp1 to dp6. The detection magnetic poles dp1 to dp6 are arranged on the outer peripheral surface of the detection rotor 312B. The detection magnetic poles dp1, dp3, and dp5 are N poles. The detection magnetic poles dp2, dp4, and dp6 are S poles. The detection magnetic poles dp1 to dp6 are arranged in the circumferential direction such that the polarities alternate on the outer peripheral surface of the detection rotor 312A.

[0167] The central angle β1 corresponding to the circumferential length of the detection magnetic pole dp1 is 10 degrees.

[0168] The central angle β2 corresponding to the circumferential length of the detection magnetic pole dp2 is 80 degrees.

[0169] The central angle β3 corresponding to the circumferential length of the detection magnetic pole dp3 is 30 degrees.

[0170] The central angle β4 corresponding to the circumferential length of the detection magnetic pole dp4 is 80 degrees.

[0171] The central angle β5 corresponding to the circumferential length of the detection magnetic pole dp5 is 80 degrees.

[0172] The central angle β6 corresponding to the circumferential length of the detection magnetic pole dp6 is 80 degrees.

[0173] The circumferential lengths of the detection magnetic poles dp1, dp3, and dp5 are different from each other. When the circumferential lengths of the detection magnetic poles dp1, dp3, and dp5 are set as B1, B3, and B5, B1 < B3 < B5 holds. The circumferential lengths of the detection magnetic poles dp2, dp4, and dp6 are the same. When the circumferential lengths of the detection magnetic poles dp2, dp4, and dp6 are set as B2, B4, and B6, B2 = B4 = B6 holds. In addition, the circumferential length of the detection magnetic pole dp5 is the same as the circumferential length of the detection magnetic pole dp2.

[0174] In addition, the detection rotor 312B may also have three non-magnetized portions NP instead of the detection magnetic poles dp2, dp4, and dp6.

[0175] When the detection rotor 312B rotates together with the drive rotor 311, the magnetic fields of the plurality of detection magnetic poles dp1, dp3, and dp5 are sequentially detected by the magnetic sensor 91. The output signal K of the magnetic sensor 91 includes signal portions corresponding to the detection magnetic poles dp1, dp3, and dp5 with different circumferential lengths. The appearance order of this signal portion when the detection rotor 312B rotates in the first direction is different from the appearance order of this signal portion when the detection rotor 312B rotates in the second direction. Therefore, the control device 100 can detect the rotation direction of the drive rotor 311 based on the output signal K of the magnetic sensor 91.

[0176] In addition, the detection rotor according to the present invention only needs to have at least three detection magnetic poles with different circumferential lengths. Preferably, at least one of the polarities and circumferential lengths of the detection magnetic poles is different from each other. The portion of the outer peripheral surface of the detection rotor other than the detection magnetic poles may also be a non-magnetized portion.

[0177] In the electric valve device 1 having the magnetic rotor 31A or the magnetic rotor 31B, the same (including substantially the same) effects as those of the present embodiment are also achieved.

[0178] In the present embodiment, the control device 100 controls the electric valve 5, but the air conditioner control device 410 may also directly control the electric valve 5. In this case, the air conditioner control device 410 is an electric valve control device.

[0179] In this specification, each term indicating the shape of components such as "cylinder" and "circular cylinder" is also used for components substantially having the shape indicated by the term. For example, a "component having a cylindrical shape" includes a component having a cylindrical shape and a component substantially having a cylindrical shape.

[0180] The above has described embodiments of the present invention, but the present invention is not limited to these examples. As long as it does not violate the gist of the present invention, structures in which those skilled in the art have appropriately added, deleted, or designed changes to the constituent elements of the above embodiments, or structures in which the features of the embodiments are appropriately combined, are also included within the scope of the present invention.

[0181] Symbol Description

[0182] 1... Electric valve device, 5... Electric valve, 10... Valve body, 11... Body member, 11a... Mounting hole, 11b... Upper surface, 12... Support member, 12a... Fitting hole, 13... Connecting member, 14... Valve chamber, 15, 16... Flow paths, 17... Valve port, 18... Valve seat, 20... Tank body, 30... Driving mechanism, 31, 31A, 31B... Magnetic rotors, 311... Driving rotor, 312, 312A, 312B... Detection rotors, 32... Valve shaft holder, 32c... Internal thread, 32s... Movable stopper, 33... Guide bushing, 33a... Base portion, 33b... Support portion, 33c... External thread, 33s... Fixed stopper, 35... Support ring, 36... Push rod nut, 37... Closing valve spring, 38... Stopping mechanism, 40... Valve core, 41... First shaft portion, 42... Second shaft portion, 43... Valve portion, 44... Step portion, 50... Stator unit, 60... Stator, 61... Phase-A stator, 61a, 61b... Pole teeth, 61c... Coil, 62... Phase-B stator, 62a, 62b... Pole teeth, 62c... Coil, 65... Terminal, 66... Stepper motor, 70... Outer shell, 74... Inner space, 75... Substrate space, 76... Partition wall, 80... Housing, 80a... Opening, 83... Connector, 85... Space, 87... Boss, 90... Sensor substrate, 90a... First end portion, 90b... Second end portion, 93... Connection terminal, 95... Substrate support member, 97... Cylindrical portion, 91... Magnetic sensor, 100... Electric valve control device, 110... Control substrate, 112... Through hole, 120... Microcomputer, 121... CPU, 122... Non-volatile memory, 123... Motor driver, 124... Working memory, 125... Communication component, cp, cp1... Driving magnetic poles, dp1~dp6... Detection magnetic poles, NP... Non-magnetized portion, L... Axis, K... Output signal.

Claims

1. An electric valve, comprising: a valve body having a valve port; a stepping motor having a drive rotor and a stator; a valve element that moves relative to the valve port according to the rotation of the drive rotor; a detection rotor coaxially connected to the drive rotor; and a magnetic sensor, characterized in that, the detection rotor has a cylindrical outer peripheral surface on which a plurality of detection magnetic poles are circumferentially arranged, the magnetic sensor detects the magnetic fields of the plurality of detection magnetic poles, the circumferential lengths of at least three of the plurality of detection magnetic poles are different from each other.

2. The electric valve according to claim 1, characterized in that, the plurality of detection magnetic poles are circumferentially arranged in such a manner that their polarities alternate on the outer peripheral surface of the detection rotor, and at least one of the polarity and the circumferential length of the plurality of detection magnetic poles is different from each other.

3. The electric valve according to claim 2, characterized in that, the plurality of detection magnetic poles are arranged in the order of the magnitude of their circumferential lengths.

4. The electric valve according to claim 1 or 2, characterized in that, the electric valve further has a stop mechanism that restricts the rotation of the drive rotor in a first direction when the drive rotor is in a reference position, when the drive rotor is in the reference position, the magnetic sensor detects the magnetic field of one of the plurality of detection magnetic poles, and hereinafter this one detection magnetic pole is referred to as the reference detection magnetic pole.

5. The electric valve according to claim 4, characterized in that, the reference detection magnetic pole is the detection magnetic pole having the smallest circumferential length among the plurality of detection magnetic poles.

6. The electric valve according to claim 5, characterized in that, the drive rotor has a cylindrical outer peripheral surface and a plurality of drive magnetic poles, the plurality of drive magnetic poles are circumferentially arranged in such a manner that their polarities alternate on the outer peripheral surface of the drive rotor, and each has the same circumferential length, the circumferential length of the reference detection magnetic pole is equal to or less than the circumferential length of the drive magnetic poles, a straight line passing through the circumferential center of the reference detection magnetic pole passes through the circumferential center of one of the plurality of drive magnetic poles.

7. The electric valve according to claim 6, characterized in that, the central angle corresponding to the circumferential length of the reference detection magnetic pole is smaller than twice the step angle of the stepping motor.

8. An electric valve device, comprising the electric valve according to claim 1 and an electric valve control device for controlling the electric valve, characterized in that, the electric valve control device obtains the rotation direction of the drive rotor based on the output signal of the magnetic sensor.

9. The electric valve device according to claim 8, characterized in that, the electric valve control device inputs pulses to the stepping motor to rotate the drive rotor, the electric valve control device detects the misalignment of the stepping motor based on the rotation angle of the drive rotor obtained from the output signal of the magnetic sensor and the rotation angle of the drive rotor corresponding to the pulses input to the stepping motor.

10. An electric valve device, having the electric valve as described in claim 4 and an electric valve control device for controlling the electric valve, characterized in that, in the operation of the electric valve control device for positioning the drive rotor at the reference position, pulses are input to the stepping motor to rotate the drive rotor in the first direction, when the output signal of the magnetic sensor does not contain a signal portion corresponding to the reference detection magnetic pole, the input of pulses to the stepping motor is stopped.

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