Motor-operated valve control device, motor-operated valve device, and motor-operated valve control method

Abstract

To provide a motor valve control device capable of determining whether a rotor can rotate normally within an appropriate rotation range.SOLUTION: A motor valve control device determines that a rotor cannot rotate normally, when a pulse number (input number Xi) input to a stepping motor from a second direction rotation restriction state Sr2 to a first direction rotation restriction state Sr1 or from the first direction rotation restriction state Sr1 to the second direction rotation restriction state Sr2 is smaller than a design number Xd, or when the input number Xi is larger than an upper limit number Xu that is larger than the design number Xd.SELECTED DRAWING: Figure 17

Description

[Technical Field]

[0001] The present invention relates to an electric valve control device, an electric valve device having the electric valve control device, and a method for controlling an electric valve. [Background technology]

[0002] Patent Document 1 discloses an example of a conventional motor-operated valve. This type of motor-operated valve is incorporated into the refrigeration cycle of an air conditioner. The motor-operated valve has a valve body, a valve disc, and a stepping motor for moving the valve disc. The stepping motor has a rotor and a stator. The rotor rotates when pulses are input to the stepping motor. The motor-operated valve has a movement mechanism that moves the valve disc in response to the rotation of the rotor. The rotor rotates between a reference position and a fully open position. When the rotor is in the reference position, a movable stopper attached to the rotor contacts a fixed stopper attached to the valve body, restricting the rotor from rotating in the valve closing direction. When the rotor is in the fully open position, the valve disc is furthest from the valve opening of the valve body.

[0003] The motor-operated valve is controlled by a motor-operated valve control device. During the initialization operation, the motor-operated valve control device inputs pulses to the stepping motor to rotate the rotor in the valve closing direction and position the rotor at the reference position. The number of pulses input to the stepping motor is a number sufficient for the movable stopper to contact the fixed stopper (hereinafter referred to as the "initialization number"). The initialization number is set to a number greater than the designed number of pulses input to the stepping motor when rotating the rotor from the fully open position to the reference position. When the rotor rotates in the valve closing direction and the movable stopper contacts the fixed stopper, the rotor is positioned at the reference position. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2019 / 130928 Summary of the Invention [Problem to be solved by the invention]

[0005] During initialization, the motor-operated valve control device inputs pulses to the stepping motor until the number of pulses input to the stepping motor reaches the initialization number. However, for example, if foreign matter contained in the refrigerant enters the moving mechanism or the moving mechanism malfunctions, the rotor may stop at a position between the reference position and the fully open position. Furthermore, the movable stopper and the fixed stopper wear due to repeated contact. As the movable stopper and the fixed stopper become worn, the rotor may rotate far beyond the reference position in the valve closing direction, making it impossible to position the rotor at the reference position. Therefore, the motor-operated valve control device may start controlling the motor-operated valve after initialization even though the motor-operated valve is not operating normally.

[0006] Therefore, an object of the present invention is to provide an electric valve control device that can determine whether a rotor can rotate normally within an appropriate rotation range, an electric valve device having an electric valve control device, and a method for controlling an electric valve. [Means for solving the problem]

[0007] In order to achieve the above object, an electric valve control device according to one aspect of the present invention comprises: An electric valve control device for controlling an electric valve having: a valve body having a valve port; a stepping motor having a rotor; a valve element that approaches the valve port when the rotor rotates in a first direction and moves away from the valve port when the rotor rotates in a second direction; a first stopper mechanism that restricts the rotation of the rotor in the first direction when the rotor is in a reference position; and a second stopper mechanism that restricts the rotation of the rotor in the second direction when the rotor is in a fully open position, The electric valve control device is (1) inputting a pulse to the stepping motor to rotate the rotor in the second direction; (2) When the motor-operated valve is in a state where the rotation of the rotor in the second direction is restricted (hereinafter referred to as the "second-direction rotation restricted state") while the rotor is being rotated in the second direction, a pulse is input to the stepping motor to rotate the rotor in the first direction, (3) When the motor-operated valve is in a state where the rotation of the rotor in the first direction is restricted (hereinafter referred to as the "first direction rotation restricted state") while the rotor is being rotated in the first direction, the number of pulses (hereinafter referred to as the "input number") input to the stepping motor during the period from the second direction rotation restricted state to the first direction rotation restricted state is acquired, (4) When the input number is equal to or greater than the designed number of pulses (hereinafter referred to as the "design number") input to the stepping motor when rotating the rotor from the fully open position to the reference position and is equal to or less than an upper limit number greater than the design number, it is determined that the rotor can rotate normally; (5) When the input number is smaller than the design number or when the input number is larger than the upper limit number, it is determined that the rotor cannot rotate normally.

[0008] In order to achieve the above object, an electric valve control device according to another aspect of the present invention comprises: An electric valve control device for controlling an electric valve having: a valve body having a valve port; a stepping motor having a rotor; a valve element that approaches the valve port when the rotor rotates in a first direction and moves away from the valve port when the rotor rotates in a second direction; a first stopper mechanism that restricts the rotation of the rotor in the first direction when the rotor is in a reference position; and a second stopper mechanism that restricts the rotation of the rotor in the second direction when the rotor is in a fully open position, The electric valve control device is (1) inputting a pulse to the stepping motor to rotate the rotor in the first direction; (2) When the motor-operated valve is in a state where the rotation of the rotor in the first direction is restricted (hereinafter referred to as a "first-direction rotation restricted state") while the rotor is being rotated in the first direction, a pulse is input to the stepping motor to rotate the rotor in the second direction, (3) When the motor-operated valve is in a state where the rotation of the rotor in the second direction is restricted (hereinafter referred to as the "second direction rotation restricted state") while the rotor is being rotated in the second direction, the number of pulses (hereinafter referred to as the "input number") input to the stepping motor from the first direction rotation restricted state to the second direction rotation restricted state is acquired, (4) When the input number is equal to or greater than the designed number of pulses (hereinafter referred to as the "design number") input to the stepping motor when rotating the rotor from the reference position to the fully open position and is equal to or less than an upper limit number greater than the design number, it is determined that the rotor can rotate normally; (5) When the input number is smaller than the design number or when the input number is larger than the upper limit number, it is determined that the rotor cannot rotate normally.

[0009] In the present invention, The electric valve control device is A voltage generated in a stator of the stepping motor due to rotation of the rotor is obtained; It is preferable to determine whether the motor-operated valve is in the first direction rotation restriction state and the second direction rotation restriction state based on at least one of (i) the area of the voltage waveform, (ii) the amplitude of waves periodically observed in the voltage waveform, and (iii) the periodic appearance of new waves different from the waves periodically observed in the voltage waveform.

[0010] In the present invention, The stator has an A-phase stator and a B-phase stator, a drive current corresponding to a pulse input to the stepping motor is supplied to the A-phase stator and the B-phase stator; It is preferable that the motor-operated valve control device obtains the voltage generated in either the A-phase stator or the B-phase stator when the drive current is supplied to the other one of the A-phase stator and the B-phase stator.

[0011] In order to achieve the above object, an electric valve device according to another aspect of the present invention comprises: The motor-operated valve and the motor-operated valve control device are included.

[0012] In order to achieve the above object, a control method for a motor-operated valve according to another aspect of the present invention includes: A control method for an electrically operated valve having a valve body having a valve port, a stepping motor having a rotor, a valve element that approaches the valve port when the rotor rotates in a first direction and moves away from the valve port when the rotor rotates in a second direction, a first stopper mechanism that restricts rotation of the rotor in the first direction when the rotor is in a reference position, and a second stopper mechanism that restricts rotation of the rotor in the second direction when the rotor is in a fully open position, (1) inputting a pulse to the stepping motor to rotate the rotor in the second direction; (2) When the motor-operated valve is in a state where the rotation of the rotor in the second direction is restricted (hereinafter referred to as the "second-direction rotation restricted state") while the rotor is being rotated in the second direction, a pulse is input to the stepping motor to rotate the rotor in the first direction, (3) When the motor-operated valve is in a state where the rotation of the rotor in the first direction is restricted (hereinafter referred to as the "first direction rotation restricted state") while the rotor is being rotated in the first direction, the number of pulses (hereinafter referred to as the "input number") input to the stepping motor during the period from the second direction rotation restricted state to the first direction rotation restricted state is acquired, (4) When the input number is equal to or greater than the designed number of pulses (hereinafter referred to as the "design number") input to the stepping motor when rotating the rotor from the fully open position to the reference position and is equal to or less than an upper limit number greater than the design number, it is determined that the rotor can rotate normally; (5) When the input number is smaller than the design number or when the input number is larger than the upper limit number, it is determined that the rotor cannot rotate normally.

[0013] In order to achieve the above object, a control method for a motor-operated valve according to another aspect of the present invention includes: A control method for an electrically operated valve having a valve body having a valve port, a stepping motor having a rotor, a valve element that approaches the valve port when the rotor rotates in a first direction and moves away from the valve port when the rotor rotates in a second direction, a first stopper mechanism that restricts rotation of the rotor in the first direction when the rotor is in a reference position, and a second stopper mechanism that restricts rotation of the rotor in the second direction when the rotor is in a fully open position, (1) inputting a pulse to the stepping motor to rotate the rotor in the first direction; (2) When the motor-operated valve is in a state where the rotation of the rotor in the first direction is restricted (hereinafter referred to as a "first-direction rotation restricted state") while the rotor is being rotated in the first direction, a pulse is input to the stepping motor to rotate the rotor in the second direction, (3) When the motor-operated valve is in a state where the rotation of the rotor in the second direction is restricted (hereinafter referred to as the "second direction rotation restricted state") while the rotor is being rotated in the second direction, the number of pulses (hereinafter referred to as the "input number") input to the stepping motor from the first direction rotation restricted state to the second direction rotation restricted state is acquired, (4) When the input number is equal to or greater than the designed number of pulses (hereinafter referred to as the "design number") input to the stepping motor when rotating the rotor from the reference position to the fully open position and is equal to or less than an upper limit number greater than the design number, it is determined that the rotor can rotate normally; (5) When the input number is smaller than the design number or when the input number is larger than the upper limit number, it is determined that the rotor cannot rotate normally. [Effects of the Invention]

[0014] According to the present invention, (1) Rotating the rotor of the motor-operated valve in a second direction; (2) When the motor-operated valve is in the second direction rotation restriction state, the rotor is rotated in the first direction. (3) When the motor-operated valve is in the first direction rotation restriction state, the number of pulses (input number) input to the stepping motor from the second direction rotation restriction state to the first direction rotation restriction state is acquired. (4) When the input number is equal to or greater than the design number and equal to or less than the upper limit number, it is determined that the rotor can rotate normally. (5) When the input number is smaller than the design number or when the input number is larger than the upper limit number, it is determined that the rotor cannot rotate normally.

[0015] Alternatively, according to the present invention, (1) Rotating the rotor of the motor-operated valve in a first direction; (2) When the motor-operated valve is in the first direction rotation restriction state, the rotor is rotated in the second direction. (3) When the motor-operated valve enters the second direction rotation restriction state, the number of pulses (input number) input to the stepping motor during the period from the first direction rotation restriction state to the second direction rotation restriction state is acquired. (4) When the input number is equal to or greater than the design number and equal to or less than the upper limit number, it is determined that the rotor can rotate normally. (5) When the input number is smaller than the design number or when the input number is larger than the upper limit number, it is determined that the rotor cannot rotate normally.

[0016] If the rotor can rotate normally between the reference position and the fully open position, when the rotor is rotated in a first direction, the first stopper mechanism restricts the rotation in the first direction (first-direction rotation restriction state), and when the rotor is rotated in a second direction, the second stopper mechanism restricts the rotation in the second direction (second-direction rotation restriction state). Furthermore, the first and second stopper mechanisms wear as they restrict rotor rotation, and as wear progresses, the rotor can rotate beyond the reference position or the fully open position. Therefore, if the rotor can rotate normally within the appropriate rotation range, which includes the range from the reference position to the fully open position, the input number will be greater than or equal to the design number and less than the upper limit number, which is greater than the design number. The upper limit number is set based on the design number, taking wear into account. Therefore, by comparing the input number with the design number and the upper limit number, it is possible to determine whether the rotor can rotate normally within the appropriate rotation range. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a block diagram of an air conditioning system having an electric valve device according to an embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view of the motor-operated valve device of FIG. [Figure 3] 3 is a diagram showing a rotor and a stator of the motor-operated valve device of FIG. 2. FIG. [Figure 4] 3 is a diagram illustrating a computer, a motor driver, and a stepping motor included in the motor-operated valve device of FIG. 2. FIG. [Figure 5] FIG. 2 is a diagram showing a schematic diagram of the positional relationship between the magnetic poles of the rotor and the pole teeth of the stator (when pulse P[1] is input). [Figure 6] FIG. 10 is a diagram showing a schematic diagram of the positional relationship between the magnetic poles of the rotor and the pole teeth of the stator (when pulse P[2] is input). [Figure 7] FIG. 10 is a diagram showing a schematic diagram of the positional relationship between the magnetic poles of the rotor and the pole teeth of the stator (when pulse P[3] is input). [Figure 8] FIG. 10 is a diagram showing a schematic diagram of the positional relationship between the magnetic poles of the rotor and the pole teeth of the stator (when pulse P[4] is input). [Figure 9] FIG. 10 is a diagram showing a schematic diagram of the positional relationship between the magnetic poles of the rotor and the pole teeth of the stator (when pulse P[5] is input). [Figure 10] FIG. 10 is a diagram showing a schematic diagram of the positional relationship between the magnetic poles of the rotor and the pole teeth of the stator (when pulse P[6] is input). [Figure 11] FIG. 10 is a diagram showing a schematic diagram of the positional relationship between the magnetic poles of the rotor and the pole teeth of the stator (when pulse P[7] is input). [Figure 12] FIG. 10 is a diagram showing a schematic diagram of the positional relationship between the magnetic poles of the rotor and the pole teeth of the stator (when pulse P[8] is input). [Figure 13] FIG. 10 is a diagram showing an example of a waveform of a voltage generated in a stator due to rotation of a rotor during initialization of the motor-operated valve device. [Figure 14] FIG. 14 is an enlarged view of a portion of the voltage waveform in FIG. 13. [Figure 15] FIG. 14 is an enlarged view of another part of the voltage waveform of FIG. [Figure 16] 3 is a flowchart showing an example of an initialization operation executed by a computer included in the motor-operated valve device of FIG. 2. [Figure 17] 16 is a flowchart showing an example of an initialization operation executed by a computer included in the motor-operated valve device of FIG. 2 (continuation of FIG. 16). DETAILED DESCRIPTION OF THE INVENTION

[0018] An electric valve device according to one embodiment of the present invention will be described below with reference to Figures 1 to 17. The electric valve device 1 according to this embodiment is used, for example, as a flow control valve that controls the flow rate of refrigerant in the refrigeration cycle of an air conditioner.

[0019] FIG. 1 is a block diagram of an air conditioning system having an electric valve device according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of the electric valve device of FIG. 1. FIG. 3 is a diagram showing the rotor and stator of the electric valve device of FIG. 2. FIG. 3 schematically shows the rotor and stator. FIG. 4 is a diagram explaining the computer, motor driver, and stepping motor of the electric valve device of FIG. 2. FIG. 4A is a diagram showing the connection between the computer, motor driver, and stepping motor of the electric valve control device. FIG. 4B shows an example of the correspondence between pulses and the drive current supplied by the motor driver to the stator. FIGS. 5 to 12 are diagrams showing the positional relationship between the magnetic poles of the rotor and the pole teeth of the stator. FIGS. 5 to 12 correspond to input of pulses P[1] to P[8]. FIGS. 5 to 12 also show the rotor and stator. FIG. 13 is a diagram showing an example of the waveform of the voltage generated in the stator by the rotation of the rotor during the initialization operation of the electric valve device. Fig. 14 is an enlarged view of a portion (period T1) of the voltage waveform in Fig. 13. Fig. 15 is an enlarged view of another portion (period T7) of the voltage waveform in Fig. 13. Figs. 16 and 17 are flowcharts showing an example of the initialization operation executed by the computer included in the motor-operated valve device of Fig. 2.

[0020] FIG. 1 shows an example of an air conditioning system 100 mounted on a vehicle. This air conditioning system 100 has a compressor 101, a condenser 102, an electric valve device 1 (electric valve 5), and an evaporator 103, which are connected in this order via piping 105. The electric valve device 1 is an expansion valve. The air conditioning system 100 also has an air conditioning control device 110. The air conditioning control device 110 is connected to the electric valve device 1 so as to be able to communicate with it. The air conditioning control device 110 uses the electric valve device 1 to control the flow rate of refrigerant flowing through the piping 105.

[0021] As shown in FIG. 2, the motor-operated valve device 1 includes a motor-operated valve 5 and a motor-operated valve control device 90.

[0022] As shown in each figure, the motor-operated valve 5 has a valve body 10 , a can 30 , a valve element 40 , a valve shaft 50 , a connecting mechanism 60 , a guide stem 70 , and a stepping motor 80 .

[0023] The valve body 10 has a main body member 11 and a valve seat member 21. The main body member 11 has a cylindrical shape. The valve seat member 21 has a disk shape. The valve seat member 21 is joined to the lower end of the main body member 11. The valve seat member 21 has a valve port 22 and a valve seat 23. The valve port 22 is a circular hole that passes through the center of the valve seat member 21 in the up-down direction (direction of the axis L). The valve seat 23 is an annular tapered surface formed on the upper surface of the valve seat member 21. The valve seat 23 surrounds the valve port 22.

[0024] The valve body 10 has a valve chamber 14. A first conduit 18 is brazed to the main body member 11. The first conduit 18 passes through the main body member 11 in the horizontal direction (left and right direction in FIG. 2 ). The first conduit 18 is connected to the valve chamber 14. A second conduit 28 is brazed to the valve seat member 21. The second conduit 28 is arranged along the vertical direction. The second conduit 28 is connected to the valve port 22.

[0025] The can 30 has a cylindrical shape with a closed upper end. The outer diameter of the can 30 is equal to the outer diameter of the main body member 11. The inner diameter of the can 30 is larger than the inner diameter of the main body member 11. The can 30 is attached to the upper end surface of the main body member 11. Specifically, the lower end of the can 30 is welded to the outer periphery of the upper end surface of the main body member 11.

[0026] The valve body 40 has a shaft portion 41, a valve portion 42, and a sleeve 43. The shaft portion 41 has a cylindrical shape. The valve portion 42 has a conical shape with its tip facing downward. The valve portion 42 is coaxially connected to the lower end of the shaft portion 41. The sleeve 43 has a cylindrical shape. The shaft portion 41 is inserted into the inside of the sleeve 43. The sleeve 43 is fixed to the shaft portion 41.

[0027] The valve element 40 faces the valve port 22 in the vertical direction in the valve chamber 14. The valve portion 42 moves toward and away from the valve seat 23. When the valve portion 42 moves away from the valve seat 23, the valve port 22 opens and the motor-operated valve 5 enters an open state. In the open state, the first conduit 18 and the second conduit 28 are connected via the valve chamber 14. When the valve portion 42 comes into contact with the valve seat 23, the valve port 22 closes and the motor-operated valve 5 enters a closed state. In the closed state, the connection between the first conduit 18 and the second conduit 28 is interrupted.

[0028] The valve shaft 50 has a first portion 51, a second portion 52, and a third portion 53. The first portion 51 and the second portion 52 have a cylindrical shape. A male thread 51c is formed on the outer peripheral surface of the first portion 51. The outer diameter of the second portion 52 is smaller than the outer diameter of the first portion 51. The second portion 52 is coaxially connected to the upper end of the first portion 51. The third portion 53 has a disk shape. The outer diameter of the third portion 53 is larger than the outer diameter of the first portion 51. The third portion 53 is coaxially connected to the lower end of the first portion 51.

[0029] An upper stopper body 55 is attached to the upper end of the first portion 51. A lower stopper body 56 is attached to the lower end of the first portion 51.

[0030] The connecting mechanism 60 connects the valve element 40 to the valve stem 50. The connecting mechanism 60 has a holder 61, a valve element support member 62, a spacer 63, a spring receiving member 65, and a valve closing spring 66.

[0031] The holder 61 has a cylindrical shape with a closed upper end. The holder 61 is fixed to the third portion 53 of the valve stem 50. Specifically, the valve stem 50 has a cylindrical fixing portion 54 extending downward from the lower surface of the third portion 53, and the fixing portion 54 is inserted into a through-hole formed in an upper wall portion 61a of the holder 61 and then expanded in diameter. As a result, the upper wall portion 61a is held by the third portion 53 and the fixing portion 54. The inner space of the holder 61 is connected to the valve chamber 14 via a pressure equalizing hole 61b.

[0032] The valve disc support member 62 has an annular disk shape. The outer peripheral edge of the valve disc support member 62 is crimped to the lower end of the holder 61. A spacer 63 having an annular disk shape is disposed on the upper surface of the valve disc support member 62. The shaft portion 41 of the valve disc 40 is inserted into the inside of the valve disc support member 62 and the inside of the spacer 63. The sleeve 43 of the valve disc 40 prevents the shaft portion 41 from falling off the valve disc support member 62. The valve disc support member 62 supports the valve disc 40 so that it can move up and down.

[0033] The spring receiving member 65 has a cylindrical shape. A flange 65a that protrudes radially outward is formed at the lower end of the spring receiving member 65. The spring receiving member 65 is disposed inside the holder 61 so as to be movable up and down. The lower surface of the spring receiving member 65 contacts the upper end of the shaft portion 41 of the valve body 40.

[0034] The valve-closing spring 66 is a compression coil spring. The valve-closing spring 66 is disposed between the upper wall portion 61a of the holder 61 and the flange 65a of the spring receiving member 65. The valve-closing spring 66 presses the spring receiving member 65 against the shaft portion 41 of the valve body 40. The valve-closing spring 66 presses the valve body 40 downward via the spring receiving member 65.

[0035] The valve element 40 and the valve shaft 50 may be directly connected to each other without the intermediation of the connecting mechanism 60.

[0036] The guide stem 70 has a columnar portion 71 , a cylindrical portion 72 , a holding portion 73 , and a disk 74 .

[0037] An upper stopper portion 75 is formed at the upper end of the cylindrical portion 71. A lower stopper portion 76 is formed at the lower end of the cylindrical portion 71. A female thread 71c that penetrates the cylindrical portion 71 in the vertical direction is provided in the center of the cylindrical portion 71. The female thread 71c is threadedly engaged with the male thread 51c of the valve stem 50.

[0038] The cylindrical portion 72 is connected to the lower end of the columnar portion 71. The third portion 53 of the valve shaft 50, the lower stopper body 56, and the connecting mechanism 60 are arranged inside the cylindrical portion 72. The inner diameter of the cylindrical portion 72 is equal to the outer diameter of the holder 61. The cylindrical portion 72 supports the holder 61 so that it can move up and down.

[0039] The retaining portion 73 is an annular protrusion that protrudes radially outward from the outer circumferential surface of the cylindrical portion 72. The disk 74 is formed in an annular shape. The inner peripheral edge of the disk 74 is embedded in the retaining portion 73. The outer peripheral edge of the disk 74 is welded to the inner peripheral edge of the upper end surface of the main body member 11. The guide stem 70 is fixed to the valve body 10.

[0040] The stepping motor 80 includes a rotor 81 and a stator 82 .

[0041] The rotor 81 has a cylindrical shape with a closed upper end. A plurality of north poles and a plurality of south poles are formed on the outer peripheral surface of the rotor 81. The plurality of north poles and a plurality of south poles extend in the vertical direction. As shown in FIG. 3, the plurality of north poles and a plurality of south poles are alternately arranged at equal angular intervals in the circumferential direction. In this embodiment, the rotor 81 has 12 north poles and 12 south poles. The angle between adjacent north poles and south poles is 15 degrees.

[0042] The rotor 81 is rotatably disposed inside the can 30. An upper wall portion 81a of the rotor 81 is connected to the second portion 52 of the valve stem 50 via a connector 83. The valve stem 50 rotates together with the rotor 81. When the valve stem 50 rotates, the valve stem 50, the connecting mechanism 60, and the valve element 40 move up and down due to the screw feed action between the male thread 51c and the female thread 71c of the guide stem 70. The valve stem 50 and the guide stem 70 form a movement mechanism that moves the valve element 40 in accordance with the rotation of the rotor 81.

[0043] The stator 82 has a cylindrical shape. The stator 82 is disposed on the outside of the can 30. The stator 82 has an A-phase stator 85 and a B-phase stator 86.

[0044] The A-phase stator 85 has a plurality of claw-pole-shaped pole teeth 85a, 85b on its inner circumference. In FIG. 3, the radially outer side of the A-phase stator 85 corresponds to the upper side, and the radially inner side corresponds to the lower side. The tips of the pole teeth 85a face downward, and the tips of the pole teeth 85b face upward. The pole teeth 85a and the pole teeth 85b are alternately arranged at equal angular intervals in the circumferential direction. In this embodiment, the A-phase stator 85 has 12 pole teeth 85a and 12 pole teeth 85b. The angle between adjacent pole teeth 85a and pole teeth 85b is 15 degrees. When the coil 85c of the A-phase stator 85 is energized, the pole teeth 85a and the pole teeth 85b become magnetic poles of opposite polarity.

[0045] The B-phase stator 86 has a plurality of claw-pole-shaped pole teeth 86a, 86b on its inner circumference. In FIG. 3, the radially outer side of the B-phase stator 86 corresponds to the upper side, and the radially inner side corresponds to the lower side. The tips of the pole teeth 86a face downward, and the tips of the pole teeth 86b face upward. The pole teeth 86a and the pole teeth 86b are alternately arranged at equal angular intervals in the circumferential direction. In this embodiment, the B-phase stator 86 has 12 pole teeth 86a and 12 pole teeth 86b. The angle between adjacent pole teeth 86a and pole teeth 86b is 15 degrees. When the coil 86c of the B-phase stator 86 is energized, the pole teeth 86a and the pole teeth 86b become magnetic poles of mutually opposite polarities.

[0046] The A-phase stator 85 is disposed coaxially on the B-phase stator 86. When viewed from the direction of the axis L, the angle between the pole teeth 85a of the A-phase stator 85 and the pole teeth 86a of the B-phase stator 86, which are adjacent to each other, is 7.5 degrees. In other words, the B-phase stator 86 is located at a position rotated by 7.5 degrees around the axis L with respect to the A-phase stator 85 from the position where the pole teeth 85a and 86a are aligned in the direction of the axis L. As shown in FIG. 4A , terminals A1 and A2 of the coil 85c of the A-phase stator 85 and terminals B1 and B2 of the coil 86c of the B-phase stator 86 are connected to a motor driver 94 of the motor-operated valve control device 90.

[0047] Pulses P (P[1] to P[8]) are input to stepping motor 80, causing rotor 81 to rotate. Specifically, a drive current corresponding to the pulses P is supplied to stator 82 of stepping motor 80, causing rotor 81 to rotate. In this specification, "inputting pulses P to stepping motor 80" is synonymous with "supplying a drive current corresponding to the pulses P to stator 82 of stepping motor 80."

[0048] Pulses P[1] to P[8] shown in Fig. 4B are input in sequence to the stepping motor 80. Figs. 5 to 12 show examples of the positional relationship between the rotor 81 and the stator 82 when pulses P[1] to P[8] are input. In Figs. 5 to 12, to make it easier to understand the positional relationship between the rotor 81 and the stator 82 (A-phase stator 85, B-phase stator 86), a reference pole tooth 85a and a reference magnetic pole (S pole) of the rotor 81 are indicated by black circles.

[0049] When the rotor 81 is rotated in the first direction (clockwise in FIGS. 5 to 12), pulses P are cyclically input to the stepping motor 80 in ascending order (the order of pulses P[1] to P[8]). The valve stem 50 rotates in the first direction together with the rotor 81, and the valve stem 50 moves downward due to the screw feed action between the male thread 51c of the valve stem 50 and the female thread 71c of the guide stem 70. The linking mechanism 60 and the valve disc 40 also move downward together with the valve stem 50. The valve disc 40 contacts the valve seat 23, closing the valve port 22 (closed valve state). The rotor 81 is in the closed valve position Rc at this time. When the rotor 81 is further rotated in the first direction, the valve closing spring 66 is compressed, and the linking mechanism 60 (holder 61, valve disc support member 62) moves further downward together with the valve stem 50. The valve disc 40 does not move downward. When the upper stopper body 55 comes into contact with the upper stopper portion 75 of the guide stem 70, the rotation of the rotor 81 in the first direction is restricted. The position of the rotor 81 at this time is the reference position Rx. The upper stopper body 55 and the upper stopper portion 75 form a first stopper mechanism S1 that restricts the rotation of the rotor 81 in the first direction.

[0050] To rotate the rotor 81 in the second direction (counterclockwise in FIGS. 5 to 12), pulses P are cyclically input to the stepping motor 80 in descending order (pulses P[8] to P[1]). The valve shaft 50 rotates in the second direction together with the rotor 81, and the valve shaft 50 moves upward due to the screw feed action between the male thread 51c of the valve shaft 50 and the female thread 71c of the guide stem 70. The connecting mechanism 60 (holder 61, valve disc support member 62) also moves upward together with the valve shaft 50. The valve disc 40 moves upward together with the valve disc support member 62, and the valve disc 40 separates from the valve seat 23, opening the valve port 22 (open valve state). The rotor 81 is further rotated in the second direction. When the lower stopper body 56 contacts the lower stopper portion 76 of the guide stem 70, rotation of the rotor 81 in the second direction is restricted. At this time, the rotor 81 is in the fully open position Rz. When the rotor 81 is in the fully open position Rz, the valve body 40 is farthest from the valve port 22. The lower stopper body 56 and the lower stopper portion 76 form a second stopper mechanism S2 that restricts the rotation of the rotor 81 in the second direction.

[0051] In the electric valve 5, the central axes of the valve body 10 (main body member 11, valve seat member 21, valve port 22, valve seat 23), can 30, valve body 40, valve shaft 50, connecting mechanism 60 (holder 61, spring receiving member 65), guide stem 70 (cylindrical portion 71, cylindrical portion 72, disc 74) and stepping motor 80 (rotor 81, stator 82) each coincide with the axis L.

[0052] The main body member 11, the valve seat member 21, the can 30, the valve body 40 and the valve shaft 50 are made of metal such as stainless steel, etc. The guide stem 70 is made of synthetic resin.

[0053] The motor-operated valve control device 90 has a substrate 91 on which multiple electronic components (not shown) are mounted. As shown in Fig. 1, the motor-operated valve control device 90 has a non-volatile memory 92, a communication device 93, a motor driver 94, and a computer 95. The motor-operated valve control device 90 controls the motor-operated valve 5 based on commands from the air conditioner control device 110.

[0054] The nonvolatile memory 92 stores data that needs to be retained even when the power is turned off. The nonvolatile memory 92 is, for example, an EEPROM or a flash memory. The nonvolatile memory 92 stores a design number Xd and an upper limit number Xu.

[0055] The design number Xd is the designed number of pulses input to the stepping motor 80 when the rotor 81 is rotated from the fully open position Rz to the reference position Rx (or when the rotor 81 is rotated from the reference position Rx to the fully open position Rz). The first stopper mechanism S1 and the second stopper mechanism S2 wear out by restricting the rotation of the rotor 81. When the first stopper mechanism S1 and the second stopper mechanism S2 wear out, the rotor 81 becomes rotatable to a position past the fully open position Rz in the second direction or past the reference position Rx in the first direction, thereby expanding the rotatable range of the rotor 81. Therefore, the upper limit number Xu is set to a number greater than the design number Xd, taking into account the expansion of the rotatable range due to wear. Specifically, the upper limit number Xu is set to a number greater than the design number Xd in accordance with the amount of wear allowable in the first stopper mechanism S1 and the second stopper mechanism S2. For example, the upper limit number Xu is set to a number that is 105 to 120% of the design number Xd. The rotation range of the rotor 81 when pulses P equal to the upper limit number Xu are input to the stepping motor 80 is the maximum rotatable range W, which includes the range from the fully open position Rz to the reference position Rx. When the rotor 81 is rotatable at least in the range from the fully open position Rz to the reference position Rx, and is rotatable at most within the maximum rotatable range W, the rotor 81 is rotatable within an appropriate rotation range.

[0056] The communication device 93 is communicably connected to the air conditioner control device 110 via a wired communication bus 120. The air conditioner system 100 employs a communication method such as a Local Interconnect Network (LIN) or a Controller Area Network (CAN). The communication device 93 may also be connected to the air conditioner control device 110 so as to be able to communicate wirelessly.

[0057] The motor driver 94 supplies a drive current to the stepping motor 80 based on a pulse P input from the computer 95. Fig. 4B shows an example of the correspondence between the pulse P and the drive current supplied by the motor driver 94. In Fig. 4B, (+) indicates that a drive current is supplied from terminal A1 to terminal A2 or from terminal B1 to terminal B2, (-) indicates that a drive current is supplied from terminal A2 to terminal A1 or from terminal B2 to terminal B1, and (0) indicates that no drive current is supplied.

[0058] When the motor driver 94 receives a pulse P[1] from the computer 95, it supplies a drive current from terminal A1 to terminal A2 to the coil 85c (+) and does not supply a drive current to the coil 86c (0).

[0059] When the motor driver 94 receives a pulse P[2] from the computer 95, it supplies a driving current (+) from terminal A1 to terminal A2 to the coil 85c, and a driving current (+) from terminal B1 to terminal B2 to the coil 86c.

[0060] When the motor driver 94 receives the pulse P[3] from the computer 95, it does not supply a drive current to the coil 85c (0) and supplies a drive current from the terminal B1 to the terminal B2 to the coil 86c (+).

[0061] When the motor driver 94 receives a pulse P[4] from the computer 95, it supplies a drive current (-) from terminal A2 to terminal A1 to the coil 85c, and a drive current (+) from terminal B1 to terminal B2 to the coil 86c.

[0062] When the motor driver 94 receives the pulse P[5] from the computer 95, it supplies a drive current (-) from the terminal A2 to the terminal A1 to the coil 85c, and does not supply a drive current (0) to the coil 86c.

[0063] When the motor driver 94 receives the pulse P[6] from the computer 95, it supplies a drive current (-) from terminal A2 to terminal A1 to the coil 85c, and a drive current (-) from terminal B2 to terminal B1 to the coil 86c.

[0064] When the motor driver 94 receives the pulse P[7] from the computer 95, it does not supply a drive current to the coil 85c (0) and supplies a drive current from the terminal B2 to the terminal B1 to the coil 86c (-).

[0065] When the motor driver 94 receives a pulse P[8] from the computer 95, it supplies a driving current (+) from terminal A1 to terminal A2 to the coil 85c, and a driving current (-) from terminal B2 to terminal B1 to the coil 86c.

[0066] The computer 95 is a microcomputer for embedded devices that incorporates a CPU, ROM, RAM, an input / output interface, an A / D converter, etc. into a single package. The computer 95 may also include a non-volatile memory 92, a communication device 93, and a motor driver 94. The computer 95 functions as a rotation control unit 96, a voltage acquisition unit 97, and a state determination unit 98 by the CPU executing a program stored in the ROM.

[0067] The rotation control unit 96 inputs pulses P to the stepping motor 80 to rotate the rotor 81 in a first direction or a second direction. Specifically, the rotation control unit 96 inputs pulses P[1] to P[8] to the motor driver 94 based on a command received from the air conditioner control device 110. The motor driver 94 supplies drive current to the coil 85c of the A-phase stator 85 and the coil 86c of the B-phase stator 86 in accordance with the input pulses P[1] to P[8].

[0068] The voltage acquisition unit 97 acquires the voltage generated in the stator 82 due to the rotation of the rotor 81 (the voltage electromagnetically induced in the stator 82). Specifically, the voltage acquisition unit 97 acquires the voltage VB generated between terminals B1 and B2 of the coil 86c of the B-phase stator 86 when the rotation control unit 96 supplies a drive current only to the coil 85c of the A-phase stator 85 in response to pulses P[1] and P[5]. The voltage acquisition unit 97 acquires the voltage VA generated between terminals A1 and A2 of the coil 85c of the A-phase stator 85 when the rotation control unit 96 supplies a drive current only to the coil 86c of the B-phase stator 86 in response to pulses P[3] and P[7]. The voltage acquisition unit 97 may also acquire the voltage VA and the voltage VB when the rotation control unit 96 supplies a drive current to the coil 85c and the coil 86c in response to pulses P[1] to P[8]. In this case, the voltage acquisition unit 97 separates the voltage generated between terminals A1 and A2 by the drive current from the electromagnetically induced voltage VA, and separates the voltage generated between terminals B1 and B2 by the drive current from the electromagnetically induced voltage VB, thereby acquiring the voltage VA and the voltage VB.

[0069] The state determination unit 98 determines the state of the motor-operated valve 5 based on the waveforms of the voltages VA and VB acquired by the voltage acquisition unit 97 during an operation to position the rotor 81 at the reference position Rx (hereinafter referred to as the "initialization operation"). The motor-operated valve 5 has a rotation permitted state Sp, a first-direction rotation restricted state Sr1, and a second-direction rotation restricted state Sr2. The rotation permitted state Sp is a state in which rotation of the rotor 81 in the first direction and the second direction is permitted. The first-direction rotation restricted state Sr1 is a state in which rotation of the rotor 81 in the first direction is restricted. The second-direction rotation restricted state Sr2 is a state in which rotation of the rotor 81 in the second direction is restricted.

[0070] The method by which the state determination unit 98 determines the state of the motor-operated valve 5 based on the waveforms of the voltages VA and VB will be described.

[0071] 13 to 15 show examples of the waveforms of voltages VA and VB measured during the initialization operation. During each of periods T1 to T9, pulses P[1] to P[8] are input to the stepping motor 80 in ascending order. Although not shown in FIG. 13, the waveforms of voltages VA and VB before period T1 are the same (or substantially the same) as the waveforms of voltages VA and VB during period T1. In this embodiment, the period of pulse P is 8 ms, and one period T is 64 ms. During period T, pulses P[1] to P[8] are input. At time tc, the valve element 40 contacts the valve seat 23, and the rotor 81 is positioned at the closed position Rc. At time tx, the upper stopper body 55 contacts the upper stopper portion 75, and the rotor 81 is positioned at the reference position Rx. Rotation of the rotor 81 in the first direction is permitted before time tx, and is restricted after time tx.

[0072] The waveform of voltage VA includes A waves (a1 to a9), B waves (b1 to b9), C waves (c1 to c9), D waves (d1 to d9), and E waves (e7 to e9). Waves A and B are negative voltage (-V) waves observed periodically throughout the entire period T. Waves C and D are positive voltage (+V) waves observed periodically throughout the entire period T. Wave E is a positive voltage (+V) wave observed periodically after time tx.

[0073] If the areas of the waveform (including C and D waves) in the section corresponding to pulse P[7] in periods T1 to T9 are SA1 to SA9, the areas SA6 to SA9 in periods T6 to T9 after time tx are smaller than the areas SA1 to SA5 in periods T1 to T5 before time tx. Note that the area of the waveform is the area of the region surrounded by the horizontal axis corresponding to voltage 0 and the waveform itself.

[0074] Furthermore, the D wave is a positive voltage with a relatively large amplitude (d1 to d5) before time tx, and becomes a positive voltage with a relatively small amplitude (d6 to d9) after time tx.

[0075] Furthermore, E waves are not observed before time tx, but are observed periodically after time tx (e7 to e9). In other words, E waves are new waves that are different from the waves observed periodically throughout the entire period T, and appear periodically after time tx.

[0076] The waveform of voltage VB includes F waves (f1 to f9), G waves (g1 to g9), H waves (h1 to h9), J waves (j1 to j9), K waves (k1 to k9), and M waves (m7 to m9). F waves and G waves are positive voltage (+V) waves observed periodically throughout the entire period T. H waves, J waves, and K waves are negative voltage (-V) waves observed periodically throughout the entire period T. M waves are positive voltage (+V) waves observed periodically after time tx.

[0077] If the areas of the waveform (including F, G, and H waves) in the section corresponding to pulse P[1] in periods T1 to T9 are SB1 to SB9, the areas SB7 to SB9 in periods T7 to T9 after time tx are smaller than the areas SB1 to SB6 in periods T1 to T6 before time tx.

[0078] Furthermore, the G wave is a relatively large amplitude positive voltage before time tx (g1-g6), and becomes a relatively small amplitude negative voltage after time tx (g7-g9).Furthermore, after time tx, the G wave combines with the H wave to form a single wave (g7-g9).

[0079] Furthermore, the K wave is a negative voltage with a relatively small amplitude before time tx (k1 to k5), and becomes a negative voltage with a relatively large amplitude after time tx (k7 to k9).

[0080] Furthermore, M waves are not observed before time tx, but are observed periodically after time tx (m7 to m9). In other words, M waves are new waves that are different from the waves observed periodically throughout the entire period T, and they appear periodically after time tx.

[0081] As a result, the waveforms of voltage VA and voltage VB differ before and after time tx as follows. (i) The area of the waveform in the period T after time tx is smaller than the area of the waveform in the period T before time tx. (ii) The amplitude of the wave after time tx is different from the amplitude of the wave before time tx. (iii) Waves different from those observed before time tx periodically appear after time tx.

[0082] The waveforms of voltages VA and VB differ before and after the rotation of rotor 81 in the second direction is restricted by second stopper mechanism S2, similar to the waveforms in Figures 13 to 15. Furthermore, for example, if a foreign object enters the movement mechanism (valve stem 50 and guide stem 70) or if the movement mechanism breaks down, the rotation of rotor 81 is also restricted. In such cases, the waveforms of voltages VA and VB differ before and after the rotation of rotor 81 is restricted, similar to the waveforms in Figures 13 to 15.

[0083] Therefore, the state determination unit 98 can determine that the rotation of the rotor 81 in the first direction has been restricted and that the rotation of the rotor 81 in the second direction has been restricted by detecting at least one of the phenomena (i) to (iii) above in the waveform of the voltage VA or the waveform of the voltage VB.

[0084] The state determination unit 98 determines that the motor-operated valve 5 is in the rotation permitted state Sp when none of the phenomena shown in (i) to (iii) above is detected in the waveforms of the voltage VA and the voltage VB acquired by the voltage acquisition unit 97 during the initialization operation. The state determination unit 98 determines that the motor-operated valve 5 is in the first-direction rotation restricted state Sr1 when at least one of the phenomena shown in (i) to (iii) above is detected when the rotor 81 is rotating in the first direction. The state determination unit 98 determines that the motor-operated valve 5 is in the second-direction rotation restricted state Sr2 when at least one of the phenomena shown in (i) to (iii) above is detected when the rotor 81 is rotating in the second direction.

[0085] The state determination unit 98 may be configured to determine that the motor-operated valve 5 is in the first-direction rotation-restricted state Sr1 when two or more of the phenomena (i) to (iii) above are detected while the rotor 81 is rotating in the first direction, and to determine that the motor-operated valve 5 is in the second-direction rotation-restricted state Sr2 when two or more of the phenomena (i) to (iii) above are detected while the rotor 81 is rotating in the second direction. The state determination unit 98 may be configured to determine that the motor-operated valve 5 is in the rotation-permitted state Sp when the motor-operated valve 5 is neither in the first-direction rotation-restricted state Sr1 nor in the second-direction rotation-restricted state Sr2.

[0086] The following is an example in which the state determination unit 98 determines whether the state of the motor-operated valve 5 is the first-direction rotation restricted state Sr1 or the rotation permitted state Sp when the rotor 81 is rotated in the first direction.

[0087] When the rotor 81 is rotating in the first direction, the state determination unit 98 determines the state of the motor-operated valve 5 at the timing when the current period T during which pulses P[1] to P[8] are input ends. Specifically, the state determination unit 98 performs the following steps (1) to (8).

[0088] (1) The state determination unit 98 calculates the area SA of the waveform of the voltage VA in a section corresponding to the pulse P[7] in the current period T. Then, when the state determination unit 98 detects that the area SA is smaller than the area SA of the waveform in a section corresponding to the pulse P[7] in the immediately previous period T by a predetermined first area determination value or more, the state determination unit 98 determines that the motor-operated valve 5 is in the first-direction rotation restricted state Sr1. Note that the area SA may be the area of the waveform in a part of the period T, or may be the area of the waveform in the entire period T.

[0089] (2) The state determination unit 98 acquires the amplitude of the D wave in the current period T from the waveform of the voltage VA. Then, when the state determination unit 98 detects that the amplitude is smaller than the amplitude of the D wave in the immediately preceding period T by a predetermined first amplitude determination value or more, it determines that the motor-operated valve 5 is in the first-direction rotation restricted state Sr1.

[0090] (3) When the state determination unit 98 detects that a new E wave, which is different from the A wave, B wave, C wave, and D wave observed over all periods T, appears periodically over multiple consecutive periods T (e.g., three periods) in the waveform of the voltage VA, the state determination unit 98 determines that the motor-operated valve 5 is in the first-direction rotation restriction state Sr1.

[0091] (4) The state determination unit 98 calculates the area SB of the waveform of the voltage VB in the section corresponding to the pulse P[1] in the current period T. Then, when the state determination unit 98 detects that the area SB is smaller than the area SB of the waveform in the section corresponding to the pulse P[1] in the immediately previous period T by a predetermined second area determination value or more, the state determination unit 98 determines that the motor-operated valve 5 is in the first-direction rotation restricted state Sr1. Note that the area SB may be the area of the waveform in a portion of the period T, or may be the area of the waveform in the entire period T.

[0092] (5) The state determination unit 98 acquires the amplitude of the G wave in the current period T from the waveform of the voltage VB. Then, when the state determination unit 98 detects that the amplitude is smaller than the amplitude of the G wave in the immediately preceding period T by at least a predetermined second amplitude determination value, it determines that the motor-operated valve 5 is in the first-direction rotation restricted state Sr1.

[0093] (6) The state determination unit 98 acquires the amplitude of the K wave in the current period T from the waveform of the voltage VB. Then, when the state determination unit 98 detects that the amplitude is greater than the amplitude of the K wave in the immediately preceding period T by a predetermined third amplitude determination value or more, it determines that the motor-operated valve 5 is in the first-direction rotation restricted state Sr1.

[0094] (7) When the state determination unit 98 detects that a new M wave, which is different from the F wave, G wave, H wave, J wave, and K wave observed over all periods T, appears periodically over multiple consecutive periods T (e.g., three periods) in the waveform of the voltage VB, it determines that the motor-operated valve 5 is in the first direction rotation restriction state Sr1.

[0095] The areas and amplitudes used in the above (1), (2), (4) to (6) may be moving average values over a plurality of consecutive periods T. Also, only some of the above (1) to (7) may be performed.

[0096] (8) When it is not determined in the above (1) to (7) that the motor-operated valve 5 is in the first-direction rotation-restricted state Sr1, the state determination unit 98 determines that the motor-operated valve 5 is in the rotation-permitted state Sp.

[0097] Similarly, when the rotor 81 is rotating in the second direction, the state determination unit 98 determines whether the state of the motor-operated valve 5 is the second-direction rotation restricted state Sr2 or the rotation permitted state Sp.

[0098] The state determination unit 98 may treat the above (1) to (7) as provisional determinations, and may formally determine that the motor-operated valve 5 is in the first direction rotation restricted state Sr1 if it has provisionally determined that the motor-operated valve 5 is in the first direction rotation restricted state Sr1 a predetermined number of times, or may formally determine that the motor-operated valve 5 is in the first direction rotation restricted state Sr1 if it has not formally determined that the motor-operated valve 5 is in the first direction rotation restricted state Sr1.

[0099] Next, an example of the operation (initialization operation) of the motor-operated valve control device 90 will be described with reference to FIGS.

[0100] When the motor-operated valve control device 90 (specifically, the computer 95) receives an initialization command from the air conditioner control device 110 (S110), it functions as the rotation control unit 96 and starts inputting pulses P (descending order) to the stepping motor 80, causing the rotor 81 to rotate in the second direction (S120). As a result, a drive current corresponding to the pulses P is supplied to the stator 82, causing the rotor 81 to rotate in the second direction.

[0101] The electric valve control device 90 functions as a voltage acquisition unit 97 and acquires the voltage VA generated between terminals A1 and A2 of the coil 85c of the A-phase stator 85 and the voltage VB generated between terminals B1 and B2 of the coil 86c of the B-phase stator 86 (S130).

[0102] The motor-operated valve control device 90 functions as a state determination unit 98, and when the current period T during which pulses P[8] to P[1] are input ends, it determines the state of the motor-operated valve 5 (the second direction rotation restricted state Sr2 or the rotation permitted state Sp) based on the voltages VA and VB (S140).

[0103] When the motor-operated valve 5 is in the rotation-permitted state Sp (N in S150), the motor-operated valve control device 90 repeats steps S130 to S150.

[0104] When the motor-operated valve 5 is in the second direction rotation restricted state Sr2 (Y in S150), the motor-operated valve control device 90 stops inputting pulses P to the stepping motor 80 (S160).

[0105] Next, the motor-operated valve control device 90 functions as the rotation control unit 96, and starts inputting pulses P (ascending order) to the stepping motor 80 to rotate the rotor 81 in the first direction (S170). As a result, a drive current corresponding to the pulses P is supplied to the stator 82, and the rotor 81 rotates in the first direction.

[0106] The electric valve control device 90 functions as a voltage acquisition unit 97 and acquires the voltage VA generated between terminals A1 and A2 of the coil 85c of the A-phase stator 85 and the voltage VB generated between terminals B1 and B2 of the coil 86c of the B-phase stator 86 (S180).

[0107] The motor-operated valve control device 90 functions as a state determination unit 98, and when the current period T during which pulses P[1] to P[8] are input ends, it determines the state of the motor-operated valve 5 (first direction rotation restricted state Sr1 or rotation permitted state Sp) based on the voltage VA and the voltage VB (S190).

[0108] When the motor-operated valve 5 is in the rotation-permitted state Sp (N in S200), the motor-operated valve control device 90 repeats steps S180 to S200.

[0109] When the motor-operated valve 5 is in the first direction rotation restricted state Sr1 (Y in S200), the motor-operated valve control device 90 stops inputting pulses P to the stepping motor 80 (S210).

[0110] Next, the electric valve control device 90 acquires the number of pulses input to the stepping motor 80 (hereinafter referred to as the "input number Xi") from when it is determined that the electric valve 5 is in the second direction rotation restriction state Sr2 to when it is determined that it is in the first direction rotation restriction state Sr1 (S220).

[0111] If the rotor 81 is rotatable at least in the range from the fully open position Rz to the reference position Rx, and is rotatable at most in the maximum rotatable range W, the input number Xi is equal to or greater than the design number Xd and equal to or less than the upper limit number Xu.

[0112] If the rotor 81 cannot rotate from the fully open position Rz to the reference position Rx, the input number Xi will be smaller than the design number Xd.

[0113] If wear of the first stopper mechanism S1 and the second stopper mechanism S2 progresses and the rotor 81 is rotatable beyond the maximum rotatable range W, the input number Xi becomes greater than the upper limit number Xu.

[0114] When the input number Xi is equal to or greater than the design number Xd and equal to or less than the upper limit number Xu (N in S230, N in S240), the motor-operated valve control device 90 notifies the air conditioner control device 110 that the initialization operation has been successfully completed, assuming that the rotor 81 can rotate normally between the fully open position Rz and the reference position Rx and that the rotor 81 is positioned at the reference position Rx (including a position near the reference position Rx) (S250).

[0115] When the input number Xi is smaller than the design number Xd (Y in S230), the motor-operated valve control device 90 notifies the air conditioner control device 110 that the initialization operation has ended abnormally (S260), since the rotation of the rotor 81 is restricted between the fully open position Rz and the reference position Rx, and the rotor 81 cannot rotate normally between the fully open position Rz and the reference position Rx.

[0116] When the input number Xi is greater than the upper limit number Xu (N in S230, Y in S240), the motor-operated valve control device 90 notifies the air conditioner control device 110 that the initialization operation has ended abnormally (S260), since the rotor 81 has rotated beyond the maximum rotatable range W and the rotor 81 cannot be positioned at the reference position Rx (including a position near the reference position Rx).

[0117] When the air conditioner control device 110 receives a notification that the initialization operation of the motor-operated valve 5 has ended normally, it starts controlling the flow rate of the refrigerant flowing through the pipe 105. When the air conditioner control device 110 receives a notification that the initialization operation of the motor-operated valve 5 has ended abnormally, it performs an operation to be performed when an abnormality occurs, such as stopping the air conditioner system 100 or causing the air conditioner system 100 to operate in a degenerated state.

[0118] As described above, the motor-operated valve device 1 according to this embodiment includes the motor-operated valve 5 and the motor-operated valve control device 90. The motor-operated valve 5 includes the valve body 10 having the valve port 22, the stepping motor 80 having the rotor 81, the valve element 40 that approaches the valve port 22 when the rotor 81 rotates in a first direction and moves away from the valve port 22 when the rotor 81 rotates in a second direction, a first stopper mechanism S1 that restricts rotation of the rotor 81 in the first direction when the rotor 81 is in a reference position Rx, and a second stopper mechanism S2 that restricts rotation of the rotor 81 in the second direction when the rotor 81 is in a fully open position Rz. The motor-operated valve control device 90 controls the motor-operated valve 5.

[0119] Then, in the initialization operation, the motor-operated valve control device 90 performs the following: (1) A pulse P is input to the stepping motor 80 to rotate the rotor 81 in the second direction; (2) When the motor-operated valve 5 enters the second direction rotation restriction state Sr2 while the rotor 81 is rotating in the second direction, a pulse P is input to the stepping motor 80 to rotate the rotor 81 in the first direction, (3) When the motor-operated valve 5 enters the first direction rotation restriction state Sr1 while the rotor 81 is rotating in the first direction, the number of pulses (input number Xi) input to the stepping motor 80 from the second direction rotation restriction state Sr2 to the first direction rotation restriction state Sr1 is acquired, (4) When the input number Xi is equal to or greater than the design number Xd and equal to or less than the upper limit number Xu, it is determined that the rotor 81 can rotate normally between the fully open position Rz and the reference position Rx and that the rotor 81 rotates within the maximum rotatable range W, and therefore the rotor 81 can rotate normally; (5) When the input number Xi is smaller than the design number Xd or when the input number Xi is larger than the upper limit number Xu, it is determined that the rotor 81 cannot rotate normally between the fully open position Rz and the reference position Rx, or that the rotor 81 rotates beyond the maximum rotatable range W, and therefore the rotor 81 cannot rotate normally.

[0120] If the rotor 81 can rotate normally between the fully open position Rz and the reference position Rx, when the rotor 81 is rotated in the second direction, the second stopper mechanism S2 restricts the rotation in the second direction (second-direction rotation restricted state Sr2), and when the rotor 81 is rotated in the first direction, the first stopper mechanism S1 restricts the rotation in the first direction (first-direction rotation restricted state Sr1). Furthermore, the first stopper mechanism S1 and the second stopper mechanism S2 wear by restricting the rotation of the rotor 81. As the wear progresses, the rotor 81 can rotate beyond the fully open position Rz or the reference position Rx. Therefore, when the rotor 81 can rotate normally within an appropriate rotation range, including the range from the fully open position Rz to the reference position Rx, the input number Xi is greater than or equal to the design number Xd and less than or equal to the upper limit number Xu. The upper limit number Xu is set based on the design number Xd, taking wear into account. From this, the motor-operated valve control device 90 can determine whether the rotor 81 can rotate normally within an appropriate rotation range by comparing the input number Xi with the design number Xd and the upper limit number Xu.

[0121] The motor-operated valve control device 90 also acquires the voltages VA and VB generated in the stator 82 of the stepping motor 80 due to the rotation of the rotor 81. The motor-operated valve control device 90 determines whether the motor-operated valve 5 is in the first-direction rotation restricted state Sr1 or the second-direction rotation restricted state Sr2 based on at least one of (i) the area of the waveforms of the voltages VA and VB, (ii) the amplitude of waves periodically observed in the waveforms of the voltages VA and VB, and (iii) the periodic appearance of new waves different from the waves periodically observed in the waveforms of the voltages VA and VB. In this way, the state of the motor-operated valve 5 can be determined by performing relatively simple processing on the voltages VA and VB.

[0122] Stator 82 also has an A-phase stator 85 and a B-phase stator 86. A drive current is supplied to A-phase stator 85 and B-phase stator 86 in accordance with pulses P input to stepping motor 80. Motor-operated valve control device 90 acquires voltage VB generated in B-phase stator 86 when drive current is supplied only to A-phase stator 85, and acquires voltage VA generated in A-phase stator 85 when drive current is supplied only to B-phase stator 86. In this manner, motor-operated valve control device 90 does not need to separate voltage VA from the voltage generated in A-phase stator 85 by the drive current, and does not need to separate voltage VB from the voltage generated in B-phase stator 86 by the drive current. Therefore, voltage VA and voltage VB can be acquired with a relatively simple configuration.

[0123] Furthermore, when the motor-operated valve control device 90 determines that the motor-operated valve 5 is in the first-directional rotation restricted state Sr1, it stops inputting pulses P to the stepping motor 80. When the motor-operated valve control device 90 determines that the motor-operated valve 5 is in the second-directional rotation restricted state Sr2, it stops inputting pulses P to the stepping motor 80. By doing so, it is possible to prevent the input of pulses P to the stepping motor 80 from continuing in a state in which the rotation of the rotor 81 is restricted. This makes it possible to suppress wear on the first stopper mechanism S1 and the second stopper mechanism S2 and improve the durability of the motor-operated valve 5.

[0124] The motor-operated valve control device 90 described above determines whether the motor-operated valve 5 is in the rotation permitted state Sp, the first-direction rotation restricted state Sr1, or the second-direction rotation restricted state Sr2. The motor-operated valve control device 90 may be configured to determine a state of the motor-operated valve 5 other than these.

[0125] According to FIG. 13, in the waveform of voltage VA, the D wave is a positive voltage with a constant amplitude (d1, d2) in each period T before time tc, and the amplitude gradually decreases from time tc to time tx (d3 to d5). Also, in the waveform of voltage VB, the K wave is a negative voltage with a constant amplitude (k1, k2) in each period before time tc, and the amplitude gradually decreases from time tc to time tx ( k 3~ k 5) These are presumably due to the fact that the rotor 81 passes the valve-closed position Rc and the valve-closing spring 66 is gradually compressed, causing the rotational speed of the rotor 81 to gradually decrease. Therefore, by detecting a gradual decrease in the amplitude of the waves in the waveform of voltage VA or voltage VB, it can be determined that the rotor 81 is in a position between the valve-closed position Rc and the reference position Rx.

[0126] Therefore, the motor-operated valve control device 90 may be configured to determine that the motor-operated valve 5 is in state Sq, in which the motor-operated valve 5 is in a position immediately before the reference position Rx, when the amplitude of the D wave periodically observed in the waveform of the voltage VA gradually decreases and / or the amplitude of the K wave periodically observed in the waveform of the voltage VB gradually decreases while the rotor 81 is rotating in the first direction. In state Sq, the rotor 81 is in a position between the valve-closed position Rc and the reference position Rx. Therefore, when the motor-operated valve control device 90 determines that the motor-operated valve 5 is in the first-direction rotation-restricted state Sr1 before determining that the motor-operated valve 5 is in state Sq while the rotor 81 is rotating in the first direction, it can determine that some abnormality has occurred and that rotation of the rotor 81 in the first direction has been restricted before the rotor 81 reaches the reference position Rx.

[0127] The motor-operated valve control device 90 described above positions the rotor 81 at the reference position Rx during the initialization operation. The motor-operated valve control device 90 may also position the rotor 81 at the fully open position Rz during the initialization operation instead of the reference position Rx.

[0128] That is, in the initialization operation, the motor-operated valve control device 90 performs the following: (1) A pulse P is input to the stepping motor 80 to rotate the rotor 81 in a first direction; (2) When the motor-operated valve 5 enters the first direction rotation restriction state Sr1 while the rotor 81 is rotating in the first direction, a pulse P is input to the stepping motor 80 to rotate the rotor 81 in the second direction, (3) When the motor-operated valve 5 enters the second direction rotation restriction state Sr2 while the rotor 81 is rotating in the second direction, the number of pulses (input number Xi) input to the stepping motor 80 from the first direction rotation restriction state Sr1 to the second direction rotation restriction state Sr2 is acquired, (4) When the input number Xi is equal to or greater than the design number Xd and equal to or less than the upper limit number Xu, it is determined that the rotor 81 can rotate normally between the reference position Rx and the fully open position Rz and that the rotor 81 rotates within the maximum rotatable range W, and therefore the rotor 81 can rotate normally; (5) When the input number Xi is smaller than the design number Xd or when the input number Xi is larger than the upper limit number Xu, it is determined that the rotor 81 cannot rotate normally between the reference position Rx and the fully open position Rz, or that the rotor 81 rotates beyond the maximum rotatable range W, and therefore the rotor 81 cannot rotate normally.

[0129] Even in this configuration, the motor-operated valve control device 90 can determine whether the rotor 81 can rotate normally within an appropriate rotation range.

[0130] Furthermore, the above-described motor-operated valve control device 90 determines whether or not the rotation of the rotor 81 is restricted based on the voltages VA and VB generated in the stator 82 of the stepping motor 80 due to the rotation of the rotor 81. The motor-operated valve control device 90 may determine whether or not the rotation of the rotor 81 is restricted by, for example, detecting the rotation angle of the rotor 81 using an angle sensor.

[0131] Furthermore, the motor-operated valve 5 described above is configured so that when the rotor 81 rotates in the first direction, the holder 61 attached to the valve stem 50 pushes the valve element 40 downward via the valve-closing spring 66 and the spring receiving member 65. The motor-operated valve 5 may be configured so that when the rotor 81 rotates in the first direction, the rotor 81 and the valve stem 50 directly push the valve element 40 downward. In this configuration, when the valve element 40 contacts the valve seat 23, the rotation of the rotor 81 in the first direction is restricted. In other words, the valve element 40 and the valve seat 23 form a first stopper mechanism, and the position of the rotor 81 when the valve element 40 contacts the valve seat 23 is the reference position Rx.

[0132] In this specification, terms indicating the shape of a member, such as "cylinder" or "column," are also used to refer to members that substantially have the shape of that term. For example, a "cylindrical member" includes both a cylindrical member and a substantially cylindrical member.

[0133] Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments. Any modifications, additions, deletions, or design changes of components made by a person skilled in the art to the above embodiments, or any combinations of features of the embodiments, are also included within the scope of the present invention as long as they do not deviate from the spirit of the present invention. [Explanation of symbols]

[0134] 1...motor-operated valve device, 5...motor-operated valve, 10...valve body, 11...body member, 14...valve chamber, 18...first conduit, 21...valve seat member, 22...valve port, 23...valve seat, 28...second conduit, 30...can, 40...valve body, 41...shaft portion, 42...valve portion, 43...sleeve, 50...valve stem, 51...first portion, 51c...male thread, 52...second portion, 53...third portion, 54...fixing portion, 55...upper stopper body, 56...lower stopper body, 60...connecting mechanism, 61...ho 61a...upper wall portion, 61b...pressure equalizing hole, 62...valve body support member, 63...spacer, 65...spring receiving member, 65a...flange, 66...valve closing spring, 70...guide stem, 71...cylindrical portion, 71c...female thread, 72...cylindrical portion, 73...retaining portion, 74...disk, 75...upper stopper portion, 76...lower stopper portion, 80...stepping motor, 81...rotor, 81a...upper wall portion, 82...stator, 83...connector, 85...A Phase stator, 85a...pole teeth, 85b...pole teeth, 85c...coil, 86...A phase stator, 86a...pole teeth, 86b...pole teeth, 86c...coil, 90...electric valve control device, 91...board, 92...non-volatile memory, 93...communication device, 94...motor driver, 95...computer, 96...rotation control unit, 97...voltage acquisition unit, 98...state determination unit, 100...air conditioning system, 101...compressor, 102...condenser, 103...steam Generator, 110...air conditioner control device, 120...wired communication bus, S1...first stopper mechanism, S2...second stopper mechanism, A1...terminal, A2...terminal, B1...terminal, B2...terminal, L...axis, P...pulse, Rc...closed valve position, Rx...reference position, Rz...fully open position, Sp...rotation allowance state, Sr1...first direction rotation restriction state, Sr2...second direction rotation restriction state, W...maximum rotatable range, Xi...number of inputs, Xd...design number, Xu...upper limit number

Claims

1. An electric valve control device for controlling an electric valve having a valve element that approaches a valve port when a rotor of a stepping motor rotates in a first direction and moves away from the valve port when the rotor rotates in a second direction, a first stopper mechanism that restricts rotation of the rotor in the first direction when the rotor is in a reference position, and a second stopper mechanism that restricts rotation of the rotor in the second direction when the rotor is in a fully open position, The state in which the motor-operated valve restricts the rotation of the rotor in the second direction is referred to as a "second-direction rotation restricted state," The state in which the motor-operated valve restricts the rotation of the rotor in the first direction is referred to as a "first-direction rotation restricted state," The designed number of pulses input to the stepping motor when rotating the rotor from the fully open position to the reference position is called the "design number." The electric valve control device is acquire an input number, which is the number of pulses input to the stepping motor, while the motor-operated valve is in a state where rotation is restricted in the second direction and the rotor is rotated in the first direction to enter the state where rotation is restricted in the first direction, or while the motor-operated valve is in a state where rotation is restricted in the first direction and the rotor is rotated in the second direction to enter the state where rotation is restricted in the second direction, 10. An electrically operated valve control device, comprising: a motor-operated valve control unit that determines that the rotor cannot rotate normally when the input number is smaller than the design number or when the input number is greater than an upper limit number that is greater than the design number.

2. The electric valve control device is A voltage generated in a stator of the stepping motor due to rotation of the rotor is obtained; 2. The motor-operated valve control device according to claim 1, wherein the motor-operated valve is determined to be in the first direction rotation restricted state and the second direction rotation restricted state based on at least one of (i) an area of the voltage waveform, (ii) an amplitude of a wave periodically observed in the voltage waveform, and (iii) a periodic appearance of a new wave different from the wave periodically observed in the voltage waveform.

3. The stator has an A-phase stator and a B-phase stator, a driving current corresponding to a pulse input to the stepping motor is supplied to the A-phase stator and the B-phase stator; 3. The motor-operated valve control device according to claim 2, wherein the motor-operated valve control device acquires the voltage generated in one of the A-phase stator and the B-phase stator when the drive current is supplied to the other one of the A-phase stator and the B-phase stator.

4. A motor-operated valve device comprising the motor-operated valve and the motor-operated valve control device according to any one of claims 1 to 3.

5. A control method for an electrically operated valve having a valve element that approaches a valve port when a rotor of a stepping motor rotates in a first direction and moves away from the valve port when the rotor rotates in a second direction, a first stopper mechanism that restricts rotation of the rotor in the first direction when the rotor is in a reference position, and a second stopper mechanism that restricts rotation of the rotor in the second direction when the rotor is in a fully open position, The state in which the motor-operated valve restricts the rotation of the rotor in the second direction is referred to as a "second-direction rotation restricted state," The state in which the motor-operated valve restricts the rotation of the rotor in the first direction is referred to as a "first-direction rotation restricted state," The designed number of pulses input to the stepping motor when rotating the rotor from the fully open position to the reference position is called the "design number." acquire an input number, which is the number of pulses input to the stepping motor, while the motor-operated valve is in a state where rotation is restricted in the second direction and the rotor is rotated in the first direction to enter the state where rotation is restricted in the first direction, or while the motor-operated valve is in a state where rotation is restricted in the first direction and the rotor is rotated in the second direction to enter the state where rotation is restricted in the second direction, A control method for a motor-operated valve, comprising determining that the rotor cannot rotate normally when the input number is smaller than the design number or when the input number is greater than an upper limit number greater than the design number.

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