Electric valve control device

Abstract

To enhance quietness of a motor-driven valve.SOLUTION: A motor-driven valve control device is connected with a motor-driven valve which adjusts a valve opening by rotation of a rotor. The motor-driven valve control device includes a rotation detection section for detecting a rotation angle of the rotor, and a rotation control section for moving the rotor toward a prescribed initial position (stop position) by indicating a rotation speed and a rotation direction of the rotor. In movement control of the rotor to the initial position, the rotation control section reduces the rotation speed of the rotor when a difference value between the rotation angle at an origin position of the rotor and the rotation angle detected for the rotor is sufficiently small.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to a motor-operated valve, and more particularly to a method for controlling a rotor. [Background technology]

[0002] Automotive air conditioners are generally configured with a compressor, a condenser, an expansion device, an evaporator, and other components arranged in a refrigeration cycle. The refrigeration cycle is provided with various control valves, such as an expansion valve as an expansion device, to control the flow of the refrigerant. With the recent spread of electric vehicles, motor-operated valves equipped with a motor as a drive unit are becoming more widely used.

[0003] Known examples of such motorized valves include one equipped with a magnetic sensor for detecting the valve opening degree (see, for example, Patent Document 1). A valve disc is provided at one end of an actuating rod that rotates with the rotor, and a magnet (sensor magnet) is provided at the other end. A magnetic sensor is provided so as to face the sensor magnet in the axial direction. The rotational motion of the rotor is converted into axial motion of the valve disc by a screw feed mechanism. By detecting changes in magnetic flux accompanying the rotation of the rotor with the magnetic sensor, the rotational angle of the sensor magnet and therefore the axial position of the valve disc can be detected, and the valve opening degree can be calculated.

[0004] A reference position is set for the actuating rod that moves up and down inside the motor-operated valve. When the rotor continues to rotate in the valve closing direction and reaches the reference position, also called the "origin," the rotor's rotation is restricted by a stopper (see, for example, Patent Document 2). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2018-135908 A [Patent Document 2] JP 2020-204344 A Summary of the Invention [Problem to be solved by the invention]

[0006] Because electric vehicles are very quiet, even the slightest mechanical noises from the motor-operated valve are easily noticeable. Among the mechanical noises generated by the motor-operated valve, the collision sound of the stopper when the rotor is moved near the reference position is particularly likely to be recognized as an abnormal noise.

[0007] A primary object of the present invention is to provide a technique for improving the quietness of a motor-operated valve. [Means for solving the problem]

[0008] An electric valve control device according to one aspect of the present invention is connected to an electric valve that adjusts the valve opening degree by rotation of a rotor. This device includes a rotation detection unit that detects the rotation angle of the rotor, and a rotation control unit that indicates the rotation speed and rotation direction of the rotor, thereby moving the rotor toward a predetermined stop position. When controlling the movement of the rotor to a stop position, the rotation control unit slows down the rotation speed of the rotor when a difference value between a reference angle value indicating the rotation angle of the rotor at a reference position and the rotation angle detected for the rotor is less than a first threshold value.

[0009] In one embodiment of the present invention, an electric valve control program causes a computer to perform the following functions: detect the rotation angle of a rotor of an electric valve; move the rotor toward a predetermined stop position by indicating the rotation speed and rotation direction of the rotor; and slow down the rotation speed of the rotor when the difference value between a reference angle value indicating the rotation angle of the rotor at a reference position and the rotation angle detected for the rotor is less than a first threshold value when controlling the movement of the rotor to the stop position. Effect of the Invention

[0010] According to the present invention, it is easy to improve the noise reduction of the motor-operated valve. [Brief description of the drawings]

[0011] [Figure 1]1 is a cross-sectional view illustrating a motor-operated valve according to an embodiment. [Diagram 2] FIG. 2 is a diagram illustrating a configuration of a stator and its surroundings. [Diagram 3] FIG. 2 is a diagram illustrating a configuration of a rotor. [Figure 4] 3 is a schematic diagram showing the relationship between a magnetic sensor, a sensor magnet, and magnetic lines of force generated from the sensor magnet; FIG. [Diagram 5] FIG. [Figure 6] 4 is a graph showing the relationship between the sensing angle of a sensor magnet and a sensor output value. [Figure 7] 1 is a graph showing the relationship between angle value and step. [Figure 8] FIG. 4 is a schematic diagram of a range of movement of a rotor. [Figure 9] FIG. 2 is a functional block diagram of the motor-operated valve control device. [Figure 10] 13 is a flowchart showing the process of an initialization process. [Figure 11] FIG. 11 is a first conceptual diagram showing the relationship between the pointing direction and the sensing angle during synchronization rise. [Figure 12] FIG. 11 is a second conceptual diagram showing the relationship between the pointing direction and the sensing angle during synchronization rise. [Figure 13] 11 is a flowchart showing the process of the origin search process in S12 of FIG. 10. [Figure 14] 11 is a first conceptual diagram showing the relationship between the pointing direction and the sensing angle during the origin search process. FIG. [Figure 15] 13 is a second conceptual diagram showing the relationship between the pointing direction and the sensing angle during the origin search process. FIG. [Figure 16] 1 is a first conceptual diagram showing the relationship between the pointing direction and the sensing angle during re-tuning. FIG. [Figure 17] FIG. 2 is a second conceptual diagram showing the relationship between the pointing direction and the sensing angle during re-tuning. [Figure 18] 11 is a conceptual diagram showing the relationship between the pointing direction and the sensing angle when the initial position is set. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. In the following description, for convenience, the positional relationship of each structure may be expressed based on the illustrated state. In addition, in the following embodiment and its modified examples, substantially the same components are given the same reference numerals, and the description thereof will be omitted as appropriate.

[0013] FIG. 1 is a cross-sectional view illustrating a motor-operated valve according to an embodiment. The motor-operated valve 1 is applied to a refrigeration cycle of an automobile air conditioner (not shown). This refrigeration cycle includes a compressor that compresses the circulating refrigerant, a condenser that condenses the compressed refrigerant, an expansion valve that throttles and expands the condensed refrigerant and sends it out in the form of mist, and an evaporator that evaporates the mist of refrigerant and cools the air inside the vehicle cabin with the latent heat of evaporation. The motor-operated valve 1 functions as an expansion valve for the refrigeration cycle.

[0014] The motor-operated valve 1 is constructed by assembling a valve body 2 and a motor unit 3. The valve body 2 has a body 5 that houses a valve portion. The body 5 functions as a "valve body." The body 5 is constructed by assembling a first body 6 and a second body 8 coaxially. Both the first body 6 and the second body 8 are made of stainless steel (hereinafter referred to as "SUS"). Since the second body 8 is provided with a valve seat 24, a material with excellent wear resistance is selected. The first body 6 has better weldability than the second body 8, and the second body 8 has better workability than the first body 6.

[0015] The first body 6 is a stepped cylinder whose outer diameter tapers stepwise downward. The outer diameter of the upper end of the first body 6 is slightly tapered, forming a locking portion 52 with a step. A male thread 10 is formed on the outer peripheral surface of the lower part of the first body 6 for assembling the motor-operated valve 1 to a piping body (not shown). The piping body is connected to piping extending from the condenser side and piping connected to the evaporator, but the details thereof will not be described. A seal receiving portion 12 consisting of an annular groove is formed on the outer peripheral surface of the first body 6 slightly above the male thread 10, and a seal ring 14 (O-ring) is fitted into it.

[0016] The first body 6 has a circular hole-shaped recessed fitting portion 16 at its lower portion. The second body 8 has a bottomed cylindrical shape, and its upper portion is press-fitted into the recessed fitting portion 16. A seal accommodating portion 18 consisting of an annular groove is formed on the outer peripheral surface of the lower portion of the second body 8, and a seal ring 20 is fitted into the seal accommodating portion 18. A valve hole 22 is provided so as to penetrate the bottom portion of the second body 8 in the axial direction, and a valve seat 24 is formed at the upper end opening of the valve hole 22. An inlet port 26 is provided at the side of the second body 8, and an outlet port 28 is provided at the lower portion. A valve chamber 30 is formed inside the first body 6 and the second body 8. The inlet port 26 and the outlet port 28 are in communication with each other via the valve chamber 30.

[0017] An actuating rod 32 extending from the rotor 60 of the motor unit 3 is inserted into the inside of the body 5. The actuating rod 32 passes through the valve chamber 30. The actuating rod 32 is obtained by cutting a bar made of a non-magnetic metal, and a needle-shaped valve element 34 is provided integrally at its lower part. The valve element 34 is attached to and detached from the valve seat 24 from the valve chamber 30 side to open and close the valve portion.

[0018] A guide member 36 is erected at the center of the upper part of the first body 6. The guide member 36 is obtained by cutting a tube material made of a non-magnetic metal into a stepped cylindrical shape, and a male thread 38 is formed on the outer circumferential surface of the axial center part. The lower end part of the guide member 36 has a large diameter, and the large diameter part 40 is press-fitted into the upper center of the first body 6 and fixed coaxially. The guide member 36 supports the operating rod 32 axially slidably with its inner circumferential surface, and supports the rotating shaft 62 of the rotor 60 rotatably and slidably with its outer circumferential surface.

[0019] A spring receiver 42 is provided on the operating rod 32 slightly above the valve body 34, and a spring receiver 44 is also provided on the bottom of the guide member 36. A spring 46 (functioning as a "biasing member") is interposed between the spring receivers 42, 44 to bias the valve body 34 in the valve closing direction.

[0020] On the other hand, the motor unit 3 is configured as a three-phase stepping motor including a rotor 60 and a stator 64. The motor unit 3 has a cylindrical can 66 with a bottom, with the rotor 60 disposed inside the can 66 and the stator 64 disposed outside the can 66. The can 66 is a cylindrical member with a bottom that covers the space in which the valve body 34 and its drive mechanism are disposed and contains the rotor 60, and defines an inner pressure space (internal space) where the pressure of the refrigerant acts and an outer non-pressurized space (external space) where the pressure of the refrigerant does not act.

[0021] The can 66 is made of a non-magnetic metal (SUS in this embodiment), and is assembled coaxially with its lower portion being fitted onto the upper end of the first body 6. The amount of insertion of the can 66 is regulated by engaging the lower end with the engaging portion 52. The body 5 and the can 66 are fixed and sealed by applying a full circumference weld (not shown) along the boundary between the lower end of the can 66 and the first body 6. The space surrounded by the body 5 and the can 66 forms the above-mentioned pressure space.

[0022] The stator 64 is configured by arranging a plurality of salient poles at equal intervals on the inner periphery of the laminated core 70. The laminated core 70 is configured by laminating annular cores in the axial direction. A bobbin 74 with a coil 73 (electromagnetic coil) attached thereto is attached to each salient pole. The coil 73 and the bobbin 74 form a "coil unit 75." In this embodiment, the motor unit has three coil units 75 for supplying three-phase current, which are provided at intervals of 120 degrees with respect to the central axis of the laminated core 70 (described in detail later).

[0023] The stator 64 is provided integrally with a case 76 of the motor unit 3. That is, the case 76 is obtained by injection molding (also called "insert molding" or "mold molding") of a corrosion-resistant resin material. The stator 64 is covered with the molded resin formed by the injection molding. The case 76 is made of the molded resin. Hereinafter, the molded product of the stator 64 and the case 76 is also called a "stator unit 78."

[0024] The stator unit 78 has a hollow structure, and is assembled to the body 5 while the can 66 is coaxially inserted therethrough. A seal receiving portion 80 consisting of an annular groove is formed on the outer peripheral surface of the first body 6 slightly below the locking portion 52, and a seal ring 82 (O-ring) is fitted into the seal receiving portion 80. The seal ring 82 is interposed between the upper outer peripheral surface of the first body 6 and the lower inner peripheral surface of the case 76, thereby preventing the outside atmosphere (water, etc.) from entering the gap between the can 66 and the stator 64.

[0025] The rotor 60 includes a cylindrical rotor core 102 attached to the rotating shaft 62, a rotor magnet 104 provided on the outer circumferential surface of the rotor core 102, and a sensor magnet 106 provided on the upper end surface of the rotor core 102. The rotor core 102 is attached to the rotating shaft 62. The rotor magnet 104 is magnetized (magnetized) into multiple poles in its circumferential direction. The sensor magnet 106 is also magnetized (magnetized) into multiple poles. The rotor magnet 104 and the sensor magnet 106 are obtained by magnetizing a magnet portion integrally molded with the rotor core 102 in a post-process, the details of which will be described later.

[0026] The rotating shaft 62 is a cylindrical shaft with a bottom, and is fitted onto the guide member 36 with its open end facing downward. A female thread 108 is formed on the inner peripheral surface of the lower part of the rotating shaft 62, and meshes with the male thread 38 of the guide member 36. A screw feed mechanism 109 formed by these threads converts the rotational motion of the rotor 60 into axial motion of the operating rod 32. This causes the valve element 34 to move (rise and fall) in the axial direction, that is, in the opening and closing direction of the valve portion.

[0027] The upper part of the actuation rod 32 is reduced in diameter, and the reduced diameter part 110 penetrates the bottom part 112 of the rotary shaft 62. An annular stopper 114 is fixed to the tip part of the reduced diameter part 110. Meanwhile, a spring 116 that urges the actuation rod 32 downward (i.e., in the valve closing direction) is interposed between the base end of the reduced diameter part 110 and the bottom part 112. With this configuration, when the valve is opened, the actuation rod 32 is displaced integrally with the rotor 60 in such a manner that the stopper 114 is engaged with the bottom part 112. Meanwhile, when the valve is closed, the spring 116 is compressed by the reaction force that the valve body 34 receives from the valve seat 24. The elastic reaction force of the spring 116 at this time can press the valve body 34 against the valve seat 24, improving the seating performance (valve closing performance) of the valve body 34.

[0028] The motor unit 3 has a circuit board 118 on the outside of the can 66. The circuit board 118 is fixed inside the case 76. In this embodiment, various circuits functioning as a control unit and a communication unit are mounted on the lower surface of the circuit board 118. Specifically, a drive circuit for driving the motor, a control circuit (microcomputer) for outputting a control signal to the drive circuit, a communication circuit for the control circuit to communicate with an external device, a power supply circuit for supplying power to each circuit and the motor (coil), etc. are mounted. The upper end of the case 76 is closed by a lid 77. The circuit board 118 is disposed in the space below the lid 77 of the case 76.

[0029] A magnetic sensor 119 is provided on the surface of the circuit board 118 facing the sensor magnet 106. The magnetic sensor 119 faces the sensor magnet 106 in the axial direction via the bottom end wall of the can 66. The magnetic flux generated by the sensor magnet 106 changes as the rotor 60 rotates. The magnetic sensor 119 detects the amount of displacement of the rotor 60 (the rotation angle of the rotor 60 in this embodiment) by detecting this change in magnetic flux. The control unit calculates the axial position of the valve body 34 and therefore the valve opening degree based on the amount of displacement of the rotor 60.

[0030] A pair of terminals 117 connected to the coil 73 extend from each bobbin 74 and are connected to a circuit board 118. A power supply terminal, a ground terminal, and a communication terminal (collectively referred to as "connection terminals 81") extend from the circuit board 118 and are each drawn out to the outside through a side wall of the case 76. A connector portion 79 is integrally provided on the side of the case 76, and the connection terminals 81 are arranged inside the connector portion 79.

[0031] A stopper 90 is formed below the rotor 60. As shown in Patent Document 2, the configuration of the stopper 90 is known. When the operating rod 32 reaches the valve-closed position, an elastic reaction force is applied to the rotor 60 by a spring 116, and the valve is stably maintained closed. Eventually, the stopper 90 comes into contact with a protrusion (locking portion) (not shown) formed as part of the guide member 36, completely restricting the rotation of the rotor 60 in the valve-closed direction. Hereinafter, the position of the rotor 60 at this time, in other words, the point where the stopper 90 comes into contact with the protrusion, is referred to as the "origin." In addition, in this embodiment, the origin is referred to as the "reference position."

[0032] Fig. 2 is a diagram showing the configuration of the stator 64 and its surroundings. Fig. 2(A) corresponds to the cross section seen from the arrow AA in Fig. 1, and is a cross section of the stator unit 78. Fig. 2(B) shows only the stator 64 (before resin molding). For reference, Fig. 2(A) also shows the can 66 and the rotor 60 (see the two-dot chain line).

[0033] Since the motor unit 3 is a three-phase motor, as shown in FIG. 2A, coil units 75 are provided at equal intervals around the axis L of the rotor 60. As also shown in FIG. 2B, slots 120a to 120c (collectively referred to as "slots 120" when no particular distinction is made) are provided at intervals of 120 degrees around the axis L on the inner periphery of the laminated core 70. In each slot 120, salient poles 122a to 122c (collectively referred to as "salient poles 122") protruding radially inward from the center are formed, and a U-phase coil 73a, a V-phase coil 73b, and a W-phase coil 73c (collectively referred to as "coils 73") are respectively assembled therein. Slits 124 having a U-shaped cross section are also formed between adjacent slots 120 to optimize the magnetic path.

[0034] The rotor magnet 104 faces the salient poles 122a to 122c via the can 66. In this embodiment, as shown in Fig. 2(A), the rotor magnet 104 is magnetized to have ten poles in the male thread, but the number of poles can be set appropriately.

[0035] Next, the configuration of the magnets in the rotor 60 will be described in detail. Fig. 3 is a diagram showing the configuration of the rotor 60. Fig. 3(A) is a perspective view, Fig. 3(B) is a front view, Fig. 3(C) is a plan view, and Fig. 3(D) is a cross-sectional view taken along the line BB in Fig. 3(C). In the diagram, "N" indicates the north pole and "S" indicates the south pole. For ease of explanation, the rotating shaft 62 (see Fig. 1) is omitted in the diagram.

[0036] The rotor 60 has a rotor magnet 104 along the outer circumferential surface of the rotor core 102, and a sensor magnet 106 at the axial end of the rotor core 102 (FIGS. 3(A) and 3(D)). The rotor magnet 104 is cylindrical, and its outer circumferential surface is magnetized with 10 poles (FIGS. 3(B) and 3(C)). On the other hand, the sensor magnet 106 is annular, and its plane is magnetized with 2 poles.

[0037] 3(D), the inner circumferential surface of rotor magnet 104 fits into annular groove 140, and the bottom surface of sensor magnet 106 fits into annular groove 144. That is, annular groove 140 functions as a fall-off prevention structure that prevents rotor magnet 104 from falling off from rotor core 102. Similarly, annular groove 144 functions as a fall-off prevention structure that prevents sensor magnet 106 from falling off from rotor core 102.

[0038] Given the above configuration, next, a description will be given of a method in which the magnetic sensor 119 detects the rotation angle of the rotor 60. In the following, the up-down direction in Fig. 1 will be referred to as the "opening / closing direction" or the "up-down direction".

[0039] FIG. 4 is a schematic diagram showing the relationship between the magnetic sensor 119, the sensor magnet 106, and the magnetic lines of force generated from the sensor magnet 106. As shown in FIG. FIG. 4 is a schematic diagram of the magnetic sensor 119 and the sensor magnet 106 as viewed from the side. As shown in FIG. 4, magnetic lines of force are generated from N to S of the sensor magnet 106 (permanent magnet). The magnetic sensor 119 located directly above the sensor magnet 106 is a rotary sensor of a known configuration that detects the magnetic lines of force generated from the sensor magnet 106. The magnetic sensor 119 detects the rotation angle of the sensor magnet 106 (rotor 60) based on the direction of the magnetic lines of force (described in detail later). Note that in this embodiment, the magnetic sensor 119 can detect the rotation angle of the sensor magnet 106, but the magnetic sensor 119 cannot directly detect the distance to the sensor magnet 106, in other words, the amount of movement of the operating rod 32 in the opening and closing direction.

[0040] FIG. 5 is a plan view of the sensor magnet 106. A rotational driving force is applied to the rotor 60 by passing a driving current through the coil 73 of the stator 64 in a manner described below. When the rotor 60 is rotated in the valve closing direction (downward) (hereinafter referred to as "downward rotation"), the actuation rod 32 (valve element 34) moves in the valve closing direction, i.e., downward in Fig. 1 in conjunction with the rotor 60. When the rotor 60 is rotated in the valve opening direction (hereinafter referred to as "upward rotation"), the actuation rod 32 (valve element 34) moves in the valve opening direction, i.e., upward in Fig. 1 in conjunction with the rotor 60.

[0041] The sensor magnet 106 also rotates in conjunction with the rotation of the rotor 60. As the sensor magnet 106 rotates, the magnetic field direction MA of the sensor magnet 106 also changes. When an XY coordinate system (corresponding to the horizontal plane in FIG. 1) is set as shown in FIG. 5, the angle that the magnetic field direction MA makes with the X-axis is defined as θ. The magnetic sensor 119 detects the rotation angle θ of the sensor magnet 106 using a known method shown in the angle sensor of Patent Document 1.

[0042] FIG. 6 is a graph showing the relationship between the sensing angle of the sensor magnet 106 and the sensor output value. The horizontal axis indicates the actual rotation angle θ of the sensor magnet 106 detected by the magnetic sensor 119 (hereinafter referred to as the "sensor angle"). The vertical axis indicates the output value of the magnetic sensor 119 (hereinafter referred to as the "sensor value"). The sensor value is further normalized by the magnetic sensor 119 within the range of "lower limit value 0 to upper limit value TA". The upper limit value TA can be set arbitrarily. As shown in FIG. 6, the magnetic sensor 119 outputs the sensor value in a sawtooth waveform corresponding to the sensor angle. Hereinafter, the value obtained by normalizing the sensor value within the above range will be referred to as the "angle value". Based on the angle value, the control circuit can detect the sensor angle, i.e., the actual rotation angle of the sensor magnet 106.

[0043] FIG. 7 is a graph showing the relationship between the angle value and the step. In this embodiment, when the valve body 34 is moved from the highest point (valve open) to the lowest point (valve closed), the rotor 60 rotates a total of four times. As will be described in detail later, the control circuit changes the drive current supplied to the three-phase coil 73 to change the magnetic field direction of the coil 73, thereby rotating the rotor 60. In this embodiment, the control circuit rotates the rotor 60 in units of u1 degrees (described in detail later). Hereinafter, this unit rotation amount is called a "step". Since 360 ​​degrees x 4 rotations ÷ u1 degrees = 1440 / u1, the control circuit instructs the rotor 60 to rotate a total of (1440 / u1) steps within the operating range of the actuation rod 32. Corresponding to the four rotations of the rotor 60, the angle value changes four times between 0 and TA.

[0044] The control circuit applies a drive current of a predetermined level to the U-phase coil 73a. At this time, a drive current of a predetermined level is also applied to the V-phase coil 73b and the W-phase coil 73c. ​​A rotation angle to be instructed to the rotor 60 is set by applying a drive current to each coil 73. Hereinafter, the direction of the magnetic field generated from the coil 73 is referred to as a "command direction." A combination of the current values ​​of the drive currents applied to the U-phase coil 73a, the V-phase coil 73b, and the W-phase coil 73c is referred to as an "excitation pattern." In this embodiment, there are N types of excitation patterns. Changing a certain excitation pattern to the next adjacent excitation pattern corresponds to a "one step" of rotation, in other words, a rotation instruction for a unit amount of rotation.

[0045] The indicated direction changes by changing the excitation pattern, in other words, by changing the excitation pattern step by step. In synchronization with the change in the indicated direction, the rotor 60 rotates and the sensed angle θ also changes. After changing the excitation pattern, the control circuit calculates the sensed angle θ from the angle value detected by the magnetic sensor 119, thereby making it possible to determine whether the indicated direction (the rotation angle indicated to the rotor 60) and the sensed angle θ (the actual rotation angle of the rotor 60 detected by the magnetic sensor 119) are aligned. Hereinafter, the state in which the sensed angle tracks the indicated direction will be referred to as "synchronization," and the state in which the sensed angle cannot track the indicated direction will be referred to as "loss of synchronization."

[0046] N types of pattern IDs are assigned to the excitation pattern. In the excitation pattern with pattern ID=N1 (hereinafter, referred to as "excitation pattern (N1)"), the drive current values ​​of U-phase coil 73a, V-phase coil 73b, and W-phase coil 73c are IU(N1), IV(N1), and IW(N1), respectively. In other words, the excitation pattern (N1) means a combination of {IU(N1), IV(N1), IW(N1)}. The magnetic field balance in coil 73 changes depending on the drive currents IU(N1), IV(N1), and IW(N1), so the indication direction can be determined by the drive current.

[0047] When the control circuit changes the excitation pattern (N1) to the excitation pattern (N1+1), i.e., {IU(N1+1), IV(N1+1), IW(N1+1)}, the direction (pointing direction) of the magnetic field generated by the three coils 73 changes, and accordingly the rotor 60 rotates upward by a unit rotation amount. When the control circuit changes the excitation pattern (N1) to the excitation pattern (N1-1), the rotor 60 rotates downward by a unit rotation amount. N types (one cycle) of excitation patterns correspond to N steps.

[0048] When the control circuit advances the excitation pattern by N steps, the rotor 60 rotates F degrees. To rotate the rotor 60 one revolution (360 degrees), the excitation pattern needs to be changed by (360 / F) periods. The sensed angle of 360 degrees (one revolution) corresponds to N × (360 / F) steps.

[0049] By changing the excitation pattern, the indicating direction is changed, and the change in indicating direction imparts a rotational driving force to the rotor 60. After the valve element 34 is seated on the valve seat 24, the elastic reaction force of the spring 116 keeps the rotor 60 stably closed.

[0050] In this embodiment, the position of the rotor 60 when the stopper 90 abuts against the guide member 36 (more precisely, the protrusion of the guide member 36) is set as the origin (reference position), and the control circuit records the angle value and excitation pattern at this time as "origin information (reference information)." Hereinafter, the abutment of the stopper 90 against the protrusion of the guide member is referred to as "rotation restriction." Also, the contact sound generated by the stopper 90 abutting against the protrusion is referred to as "collision sound."

[0051] Due to manufacturing variations, the origin information differs for each motor-operated valve 1. The circuit board 118 is equipped with a non-volatile memory. The motor-operated valve 1 is inspected for its origin position during manufacturing, and origin information specific to the motor-operated valve 1 is recorded in the non-volatile memory.

[0052] As an example, the angle value in the origin information of the motor-operated valve 1a is assumed to be "15." On the other hand, the angle value in the origin information of another motor-operated valve 1b is assumed to be "23." Since there are individual differences in the motor-operated valves 1, the origin information is also set for each motor-operated valve 1.

[0053] Assume that an initialization command is sent from the outside to the motor-operated valve 1a. The control circuit of the circuit board 118 receives various commands such as the initialization command from the master (external device). When the initialization command is received, the control circuit searches for the origin while rotating the rotor 60 downward little by little. The control circuit detects an angle value by the magnetic sensor 119 during the downward rotation. The control circuit searches for a reference position by comparing the angle value of the origin information with the angle value detected by the magnetic sensor 119. For example, the control circuit of the motor-operated valve 1a can determine that the rotor 60 may have reached the origin when the angle value detected during the downward rotation is "15". Similarly, the control circuit of the motor-operated valve 1b can determine that the rotor 60 may have reached the origin when the angle value detected during the downward rotation is "23". The details of the origin search will be described later.

[0054] The control circuit adjusts the amount of movement of the operating rod 32, that is, the valve opening degree of the motor-operated valve 1, by specifying the number of steps corresponding to the amount of rotation of the rotor 60 with respect to the origin (valve closed position).

[0055] As described above, the origin information includes the angle value and excitation pattern at the origin. In the case of FIG. 7, the angle value and excitation pattern at the origin P0 are recorded in the non-volatile memory as the origin information. When the valve body 34 is moved from the highest point to the lowest point, the rotor 60 rotates a total of four times, so that the same angle value as the origin information is detected four times. In FIG. 7, the points P1, P2, P3, and P4 correspond to these. Hereinafter, the actual origin P0 is referred to as the "true origin" or simply the "origin," and the points P1, P2, P3, and P4, which have the same origin information as the origin P0 but are not the origin, are referred to as the "false origin."

[0056] In this embodiment, when an initialization command is sent, the control circuit sets the rotor 60 to an initial position Q, which is a position where the rotor 60 is rotated upward slightly in the opening direction from the origin P0. The initial position Q corresponds to a "stop position." The control circuit first sets the rotor 60 to the initial position Q, and then adjusts the valve opening by instructing the amount and direction of rotation of the rotor 60. Thereafter, the initial position Q becomes the reference point for control. The reason for setting the origin P0 and the initial position Q at different positions will be described later.

[0057] FIG. 8 is a schematic diagram of the range of movement of the rotor 60. As shown in FIG. The right direction in FIG. 8 indicates the opening direction (upward direction) of the rotor 60, and the left direction indicates the closing direction (downward direction). The origin P0 is the limit position where the stopper 90 is restricted from rotating and the rotor 60 cannot rotate further downward. The position where the rotor 60 rotates upward from the origin P0 by M2 steps is the valve opening point W. In this embodiment, M2 may be set arbitrarily. In the range from the origin P0 to the valve opening point W, the valve body 34 is pressed against the valve seat 24 by the elastic reaction force of the spring 116, so that the valve closed state is maintained. When the rotor 60 continues to rotate upward from the origin P0 and exceeds the valve opening point W, the valve body 34 separates from the valve seat 24 and the valve is in an open state. If the rotor 60 continues to rotate upward after the valve opening point W is exceeded, the valve opening degree gradually increases, and the flow rate from the inlet port 26 to the outlet port 28 increases.

[0058] The initial position Q is the position where the rotor 60 is rotated upward by M1 steps from the origin P0. M1 in this embodiment may be arbitrarily set. Note that M1 < M2. That is, when the rotor 60 is at the initial position Q, it is in the valve-closed state.

[0059] The initial position Q may be the origin P0. However, in this case, since the stopper 90 is too close to the protrusion, a collision sound is likely to occur. For example, when the rotor 60 is at the origin P0 and the rotor 60 is started, the rotor 60 swings and a collision sound is likely to occur. Alternatively, when the rotor 60 is at the origin P0, there is also a possibility that a collision sound is generated when the vibration of the vehicle is transmitted to the rotor 60. Therefore, in this embodiment, by separating the initial position Q from the origin P0, a gap (margin) is created between the stopper 90 and the protrusion, suppressing the generation of the collision sound.

[0060] As described above, since the origin P0 is a position unique to the electric valve 1, the initial position Q also differs for each electric valve 1. When the control circuit receives the initialization command, it sets the rotor 60 to the initial position Q that is rotated upward by M1 steps from the origin P0. Hereinafter, moving the rotor 60 to the initial position Q is referred to as "initialization processing". In the following, the explanation will be centered around the initialization processing.

[0061] FIG. 9 is a functional block diagram of the electric valve control device 200. Each component of the electric valve control device 200 is realized by hardware (control circuit) including a control circuit (microcomputer) on the circuit board 118, a storage device such as a memory and a storage, and a wired or wireless communication line connecting them, and software stored in the storage device and supplying processing instructions to the arithmetic unit. The computer program may be composed of a device driver and an application program, and a library that provides common functions to these programs. Each block described below indicates a block in terms of function, not a configuration in terms of hardware unit.

[0062] The motor-operated valve control device 200 includes a data processing unit 202 , a communication unit 204 , a reference information storage unit 206 , and a rotor interface unit 208 . The communication unit 204 functions as an interface with an external device via the connection terminal 81. The rotor interface unit 208 functions as an interface with the magnetic sensor 119 and the coil unit 75. The reference information storage unit 206 stores origin information (reference information). The reference information storage unit 206 is a storage area configured in a non-volatile memory. The data processing unit 202 executes various processes based on the reference information and various data acquired from the communication unit 204 and the rotor interface unit 208. The data processing unit 202 also functions as an interface with the communication unit 204, the rotor interface unit 208, and the reference information storage unit 206.

[0063] The communication unit 204 includes a receiving unit 210 that receives data and commands from an external device, and a transmitting unit 212 that transmits data to the external device.

[0064] The rotor interface unit 208 includes a rotation instruction unit 214 and a rotation detection unit 216. The rotation instruction unit 214 outputs drive currents to the U-phase coil 73a, the V-phase coil 73b, and the W-phase coil 73c in accordance with the excitation pattern. The rotation detection unit 216 acquires an angle value from the magnetic sensor 119.

[0065] The data processing unit 202 includes a rotation control unit 218. The rotation control unit 218 controls the rotation instruction unit 214 based on the origin information. The rotation control unit 218 calculates a sensed angle based on the angle value. The rotation control unit 218 specifies an origin P0 (reference position) and an initial position Q based on the tracking ability of the sensed angle.

[0066] FIG. 10 is a flowchart showing the process of the initialization process. When the receiving unit 210 of the motor-operated valve control device 200 receives an initialization command from an external device via the connection terminal 81, the initialization process shown in FIG. 10 is started. During the initialization, the rotor 60 rotates upward by a predetermined amount (hereinafter referred to as "synchronous rise") (S10). The synchronous rise is a process for synchronizing the direction indicated by the excitation pattern with the angle value, which is the actual rotation angle of the rotor 60. In addition, when the rotor 60 starts to rotate, there is a possibility that impurities such as metal chips are caught in the screw feed mechanism 109 between the guide member 36 and the rotor 60. The upward rotation of the rotor 60 accompanying the synchronous rise can release the impurities from being caught by the rotor 60. In addition, the synchronous rise can apply an appropriate vibration to the screw feed mechanism 109, which can encourage the impurities to fall out of the screw feed mechanism 109. The synchronous rise will be described later with reference to FIG. 10 and FIG. 11.

[0067] Next, an "origin search process" is executed to move the rotor 60 to the origin P0 (S12). Before moving the rotor 60 to the initial position Q, the motor-operated valve control device 200 moves the rotor 60 to the origin P0 while shifting the designated direction in the downward rotation direction. The rotation control unit 218 identifies the origin P0 based on the origin information. Details of the origin search process will be described later with reference to Figs. 13, 14, and 15.

[0068] After the rotor 60 reaches the origin P0, the rotation control unit 218 causes the rotor 60 to step out of sync and then rotates upward to resynchronize the sensed angle with the indicated direction (hereinafter referred to as "re-tuning") (S14). In the upward rotation during re-tuning, the release of trapped impurities and their removal can be promoted in the same manner as in the synchronous upward movement. Details of re-tuning will be described later with reference to Figs. 16 and 17.

[0069] Finally, the rotation control unit 218 moves the rotor 60 to the initial position Q (hereinafter referred to as "initial position setting") (S16). The details of the initial position setting will be described later with reference to FIG.

[0070] FIG. 11 is a first conceptual diagram showing the relationship between the pointing direction and the sensing angle during synchronization rise. As described above, the indicated direction (magnetic field direction) changes little by little by switching between N types of excitation patterns. The upper part of Fig. 11 shows the indicated direction for one cycle by N types of excitation patterns as a circle. In the circle in Fig. 11, changing the indicated direction by the excitation pattern counterclockwise corresponds to the upward rotation of the rotor 60, and changing the indicated direction clockwise corresponds to the downward rotation of the rotor 60.

[0071] Changing the excitation pattern by one step changes the indicated direction A (magnetic field direction) in the coil 73, and the change in indicated direction A provides a rotational driving force of u1 degrees to the rotor 60. In this embodiment, changing the excitation pattern by N steps (one period) causes the rotor 60 to rotate F degrees. Changing the excitation pattern by (360 / F) periods causes the rotor 60 to rotate one rotation. The upper part of FIG. 11 conceptually shows the relationship between the indicated direction A (the direction of the magnetic field generated in the coil 73) and the sensed angle B (the orientation of the rotor 60).

[0072] For example, if F=360, then changing the excitation pattern by N steps (one period) causes the rotor 60 to rotate once (360 degrees). In this case, every time the excitation pattern is changed by one step, the rotor 60 rotates by (360 / N) degrees. With an N-step change, the rotor 60 rotates 360 degrees.

[0073] If F=180, the rotor 60 rotates half a turn (180 degrees) by changing the excitation pattern by N steps (one period). In this case, the rotor 60 rotates by (180 / N) degrees every time the excitation pattern is changed by one step. The N-step change causes the rotor 60 to rotate 180 degrees. After the excitation pattern is changed by N steps in a predetermined direction to rotate the rotor 60 half a turn, the excitation pattern is changed again by N steps in the same direction, causing the rotor 60 to rotate another half turn. In other words, by changing the excitation pattern by two periods in the same direction, a rotational driving force for one revolution can be applied to the rotor 60. In this way, the period of the excitation pattern and the period of the rotor 60 do not need to be the same.

[0074] When the initialization command is received, the rotation control unit 218 instructs the rotation instruction unit 214 to use a predetermined excitation pattern, and the rotation instruction unit 214 passes a drive current according to the excitation pattern. In general, when the power supply of a car air conditioner is turned on, an initialization command is transmitted to the motor-operated valve control device 200.

[0075] When the excitation pattern is set, the coil 73 generates a magnetic field in a predetermined direction, and thus the indicated direction A (the direction of the magnetic field from the coil 73) is set. The rotor 60 is given a rotational driving force by the magnetic force of the coil 73. As a result, the sensed angle B (the direction of the rotor 60) tries to approach the indicated direction A (the magnetic field direction indicated by the excitation pattern). When the excitation pattern is set, the sensed angle B may immediately coincide with the indicated direction A, but if the sensed angle B and the indicated direction A are too far apart, the sensed angle B may be drawn toward the indicated direction A but may not coincide with it.

[0076] The rotation control unit 218 switches the excitation pattern in the upward direction step by step, thereby sequentially changing the pointed direction A. In Fig. 11, since the sensed angle B is above the pointed direction A, the sensed angle B is attracted in the downward direction.

[0077] FIG. 12 is a second conceptual diagram showing the relationship between the pointing direction and the sensing angle during synchronization rise. The rotation control unit 218 moves the pointed direction A in the upward direction by N steps (one cycle). As the rotor 60 is attracted to the pointed direction A, the pointed direction A and the sensed angle B eventually synchronize with each other. Figure 12 shows the point in time when the pointed direction A and the sensed angle B are synchronized. Once synchronized, the rotor 60 rotates upward by u1 degrees in synchronization with the pointed direction A being moved one step in the upward direction.

[0078] FIG. 13 is a flowchart showing the process of the origin search process in S12 of FIG. After the motor-operated valve 1 is manufactured, an origin inspection is performed at the factory, and origin information, which is data specific to the origin, is recorded in the reference information storage unit 206. The origin search process is performed while referring to this origin information. The rotation control unit 218 detects the angle value while rotating the rotor 60. Hereinafter, the angle value registered as the origin information is called the "reference angle value," and the angle value detected for the rotor 60 is called the "current angle value." When the reference angle value and the current angle value are close to each other, the rotation control unit 218 determines that the rotor 60 is near the origin. However, as shown in FIG. 7, the current angle value also coincides with the reference angle value at the false origins P1, P2, P3, and P4. Therefore, the origin P0 cannot be identified by the origin information alone.

[0079] The rotation control unit 218 rotates the rotor 60 downward, and when the reference angle value and the current angle value approach each other, the rotation speed of the rotor 60 is reduced. This is because a collision sound occurs at the true origin P0, and the rotor 60 is slowed down to reduce the collision sound. If the rotor 60 is near the false origin, the rotor 60 can continue to rotate downward, so the reference angle value and the current angle value will eventually diverge. When the reference angle value and the current angle value diverge, the rotation control unit 218 returns the rotation speed of the rotor 60 to the original speed or increases it. On the other hand, when the true origin P0 is reached, the rotation restriction of the stopper 90 causes the sensed angle to no longer follow the indicated direction indicated by the excitation pattern. If such a phenomenon occurs, the rotation control unit 218 determines that the rotor 60 has reached the origin P0.

[0080] At the start of the origin search process, the indication direction and the sensed angle are synchronized. In this state, the rotation control unit 218 first resets the counter C to "0" (S20). The counter C is a variable prepared for determining the origin candidate. Next, the rotation control unit 218 sets the descending rotation speed of the rotor 60 to the rotation speed V1 (S22).

[0081] The rotation control unit 218 rotates the rotor 60 downward at a constant pace according to the rotation speed V1. The rotation instruction unit 214 rotates the rotor 60 downward by one step (S24). The magnetic sensor 119 detects the sensing angle, and the rotation detection unit 216 calculates the angle value (0 to TA) based on the sensor value output from the magnetic sensor 119. The rotation control unit 218 determines whether the difference value D (absolute value) between the reference angle value and the current angle value is smaller than a predetermined threshold value T1 (S26). When the difference value D is equal to or greater than the threshold value T1 (N in S26), that is, when the rotor 60 is neither near the true origin nor near the false origin, the rotation speed becomes V1 (high speed) (S28). Note that the threshold value T1 is arbitrary.

[0082] When the difference value D is less than the threshold value T1 (Y in S26), that is, when the rotor 60 is near the true origin P0 or near the false origins P1, P2, P3, P4, the rotation control unit 218 sets the rotation speed to V2 (S30). V2 < V1. The speed reduction is to reduce the collision sound in case the current position is near the true origin P0.

[0083] The rotation detection unit 216 calculates the actual rotation change amount a of the sensor magnet 106 for the downward rotation instruction of one step of the electric valve. Usually, for the rotation instruction of one step, a rotation change amount a of u1 degrees is assumed as described above. The rotation control unit 218 determines whether the rotation change amount a is less than the threshold value T2 (S32). In other words, the rotation control unit 218 determines whether the ratio (tracking property) of the change amount (rotation amount) of the sensing angle to the change amount (rotation amount) of the instruction direction is less than a predetermined threshold value. The threshold value T2 is arbitrary, but is set to about 0.3×u1 to 0.7×u1 degrees, for example.

[0084] When the amount of change in rotation a is less than the threshold value T2, it is possible that the rotor 60 has reached the origin and is subject to rotation restriction. Alternatively, it is possible that the rotor 60 is subject to temporary rotation restriction due to impurities such as metal chips. In either case, the tracking ability of the rotor 60 has decreased for some reason. In this way, when the amount of change in rotation a is less than the threshold value T2, it is possible that the rotor 60 is approaching the true origin P0, but it is also possible that the tracking ability of the rotor 60 has temporarily decreased at a position other than the true origin P0.

[0085] When the amount of change in rotation a is equal to or greater than the threshold value T2 (N in S32), that is, when rotor 60 is sufficiently tracking, rotation control unit 218 resets counter value C to "0" (S34). In addition, rotation control unit 218 clears latest origin information HP (described below) when it is stored (S36). Thereafter, the process returns to S24, and rotation control unit 218 again instructs downward rotation for one step.

[0086] On the other hand, when the rotation change amount a is less than the threshold T2 (Y in S32) and the counter value C=0 (Y in S38), that is, when the rotation change amount a becomes less than the threshold T2 for the first time, the rotation control unit 218 temporarily stores the current angle value and the current excitation pattern as the latest origin information HP (S40). After that, the rotation control unit 218 increments the counter value C (S42). When the counter value C is not zero (N in S38), that is, when "an event in which the rotation change amount a becomes less than the threshold T2 (hereinafter referred to as "tracking performance deterioration detection")" is continuously detected, the process of S40 is skipped. The latest origin information HP is maintained as it is. As long as tracking performance deterioration detection continues, the latest origin information HP is maintained and the counter value C continues to increase.

[0087] When the counter value C is less than the threshold value K1 (N in S44), the latest origin information HP is stored and the process returns to S24. The threshold value K1 is an arbitrary natural number. On the other hand, when the counter value C is equal to or greater than the threshold value K1, that is, when the tracking performance degradation detection occurs K1 times or more in succession (Y in S44), the process proceeds to re-tuning (S14) shown in FIG. 10. In this case, the rotation control unit 218 determines that the rotor 60 has reached the origin P0 at the time when the latest origin information HP is detected. Hereinafter, the angle value included in the latest origin information stored in S40 is referred to as the "origin angle value" and the excitation pattern is referred to as the "origin excitation pattern". Usually, the origin information and the latest origin information are the same. Subsequent processes are performed based on the latest origin information.

[0088] FIG. 14 is a first conceptual diagram showing the relationship between the pointing direction and the sensing angle during the origin search process. After synchronizing the indication direction A and the sensing angle B by the synchronized rise, the rotation control unit 218 rotates the rotor 60 downward while switching the excitation pattern as described in relation to Fig. 13. Near the false origin, the rotation control unit 218 slows the rotation speed of the rotor 60 from V1 to V2. For example, as shown in Fig. 14, the rotation speed of the rotor 60 is V2 (low speed) near the false origin P2, and returns to V1 when it moves away from the false origin P2.

[0089] FIG. 15 is a second conceptual diagram showing the relationship between the pointing direction and the sensing angle during the origin search process. When the rotor 60 reaches the true origin P0, the rotor 60 is restricted from rotating. Therefore, even if a downward rotation is instructed by a change in the excitation pattern, the rotor 60 cannot continue to rotate downward any further. After this, the rotation control unit 218 continues to switch the excitation pattern to the downward rotation direction. FIG. 15 corresponds to the state of "Y of S44" in FIG. 12. When the rotation restriction state is detected K1 times, it is found that the latest origin information HP corresponds to the true origin P0 when the excitation pattern advances by K1 steps after reaching the true origin P0. Although the instructed direction A advances downward, the sensed angle B cannot advance downward, so the rotor 60 temporarily steps out as shown in FIG. 15.

[0090] FIG. 16 is a first conceptual diagram showing the relationship between the pointing direction and the sensing angle during re-tuning. Even after the rotor 60 reaches the true origin P0, the rotation control unit 218 continues to switch the excitation pattern to the downward rotation direction. When the indicated direction A reaches the position shown in Fig. 16, the indicated direction A is closer to the rotor 60 from the upward direction than from the downward direction, so the rotor 60 receives a rotational driving force in the upward direction. The rotation direction of the rotor 60 is determined by the relative positional relationship between the magnetic field generated by the excitation pattern and the rotor 60.

[0091] FIG. 17 is a second conceptual diagram showing the relationship between the pointing direction and the sensing angle during re-tuning. The rotation control unit 218 continues to switch the excitation pattern to the downward rotation direction by M3 steps from the true origin P0. As shown in FIG. 16, the rotor 60 receives a rotational drive force in the upward direction. By continuing to move the excitation pattern in the downward rotation direction in this way even after reaching the true origin P0, the sensed angle B and the indicated direction A eventually approach each other relatively, and the two again match (synchronize). As described above, the rotation control unit 218 advances the excitation pattern by M3 steps from the origin excitation pattern registered in the latest origin information HP.

[0092] Since the amount of downward movement of the instruction direction A from the true origin P0 is M3 steps, the upward distance (number of steps) from the true origin P0 to the instruction direction A is "N-M3". The rotation control unit 218 may determine the angle value at a position rotated upward by "N-M3" steps from the true origin P0 based on the data shown in FIG. 7, and check whether the difference between the expected angle value and the actual angle value of the sensed angle B is within a predetermined threshold value. In other words, the rotation control unit 218 may check whether the instruction direction A and the sensed angle B are actually synchronized when the instruction direction A is moved downward by M3 steps from the true origin P0, in other words, whether a step-out has occurred.

[0093] FIG. 18 is a conceptual diagram showing the relationship between the pointing direction and the sensing angle when the initial position is set. As shown in Fig. 8, the initial position Q is located M1 steps upward from the origin P0. Since the excitation pattern has N steps per revolution, the rotation control unit 218 advances the excitation pattern in the downward direction by "N-M3-M1" steps from the state in Fig. 17. Through the above process, the rotor 60 reaches the initial position Q.

[0094] [Summary] The motor-operated valve 1, and in particular, the motor-operated valve control device 200, have been described above based on the embodiment. The motor-operated valve control device 200 reduces the speed of the rotor 60 at a point that may be the origin based on the origin information. This control method can prevent the occurrence of loud collision noise. In addition, after passing the false origin, the rotation speed of the rotor 60 is increased again, thereby shortening the time required for the origin search process.

[0095] The motor-operated valve control device 200 executes synchronous ascent before the origin search process. By moving the indicated direction in the upward rotation direction at the start of the initialization process, the sensing angle can be synchronized with the indicated direction. In addition, by rotating the rotor 60 upward before rotating it downward, it is possible to apply an appropriate vibration to the screw feed mechanism 109, so that impurities that may remain can be effectively removed.

[0096] In addition, after the rotor 60 reaches the true origin P0, the motor-operated valve control device 200 causes the rotor 60 to step out and then temporarily rotates the rotor 60 upward (see Figs. 16 and 17). Even after the rotor 60 reaches the origin, the rotor 60 is rotated upward slightly and then rotated downward, thereby facilitating the removal of impurities.

[0097] In this embodiment, the initial position Q is set at a position M1 steps away from the origin P0. When the rotor 60 starts to operate, the rotor 60 may swing up and down. If the initial position Q and the origin P0 are the same, this swinging may cause a collision sound. The rotor 60 may also swing due to the vibration of the vehicle. By providing a margin between the initial position Q and the origin P0, the generation of the collision sound can be suppressed. Furthermore, the collision between the stopper 90 and the protrusion is undesirable because it leads to wear of these parts. By providing a margin between the initial position Q and the origin P0, wear of the parts can be suppressed.

[0098] According to this embodiment, the origin (reference position) can be identified by detecting a decrease in the tracking ability of the rotor 60 by the magnetic sensor 119. The motor-operated valve control device 200 can inspect the tracking ability of the rotor 60 every time the rotor 60 is rotated by one motor-operated valve step.

[0099] In this embodiment, the position where the rotation change amount a falls below the threshold T2 K1 or more times in succession is specified as the origin. By setting K1 to a number of times, the risk of mistaking a point where the rod 32 becomes temporarily difficult to move due to impurities for the origin is reduced. K1 may be any integer equal to or greater than 1.

[0100] The present invention is not limited to the above-mentioned embodiment and modified examples, and the components can be modified without departing from the gist of the present invention. Various inventions can be formed by appropriately combining multiple components disclosed in the above-mentioned embodiment and modified examples. In addition, some components can be deleted from all the components shown in the above-mentioned embodiment and modified examples.

[0101] [Variations] In this embodiment, the valve closed position has been described as the origin (reference position). As a modified example, the valve fully open position may be set as the reference position. The reference position may be any position that serves as a reference for driving the actuating rod 32 by the rotor 60. The reference position may be set arbitrarily as long as it is a position where the rotation of the rotor 60 can be restricted by the stopper 90. The initial position (stop position) may be set as the reference position.

[0102] In the present embodiment, the driving current supplied to the stepping motor is defined by the excitation pattern, and the excitation pattern is switched by one step of the motor-operated valve to change the rotor 60 by a unit rotation amount. However, the present invention is not limited to this, and the rotor 60 may be rotated continuously at a constant speed, and the rotation control unit 218 may search for the reference position based on the tracking ability of the sensed angle per unit time.

[0103] In the present embodiment, when the reference angle value, which is an angle value included in the origin information, is close to the current angle value, which is an angle value detected for the rotor 60, the rotation control unit 218 determines that the rotor 60 is near the origin and reduces the rotation speed of the rotor 60. As a modified example, the rotation control unit 218 may determine whether the rotor 60 is near the origin based on the excitation pattern instead of the angle value. First, the excitation pattern registered as the origin information, i.e., the step value of the excitation pattern set at the origin, is called the "reference excitation value," and the step value of the excitation pattern actually set for the rotor 60 is called the "current excitation value." When the reference excitation value and the current excitation value are close to each other, the rotation control unit 218 determines that there is a possibility that the rotor 60 is near the origin.

[0104] Specifically, the rotation control unit 218 rotates the rotor 60 downward, and in S26 of Fig. 13, determines whether or not the difference value DX (absolute value) between the reference excitation value and the current excitation value is smaller than a predetermined threshold value TX. When the difference value DX is smaller than the threshold value TX (Y in S26), the rotation control unit 218 sets the rotation speed to V2 (low speed). In this way, it may be determined whether or not the rotor 60 is near the origin based on the excitation pattern instead of the angle value.

[0105] In the present embodiment, the reference position is specified on the condition that the rotation change amount a is continuously below the threshold value T2. As a modified example, the rotation control unit 218 may specify the reference position when the total number of times that the rotation change amount a falls below the threshold value T2 is equal to or greater than a predetermined number of times, regardless of whether the detection is continuous or not.

[0106] In the above embodiment, a configuration in which the magnetic sensor 119 faces the sensor magnet 106 in the axial direction is exemplified (see FIG. 1). In a modified example, the magnetic sensor may be disposed to the side (radially outward) of the sensor magnet. That is, the two may face each other in the radial direction. The outer peripheral surface of the sensor magnet may be magnetized. The number of poles may be appropriately set, for example, to two poles on the valve body.

[0107] In the above embodiment, a configuration in which the rotor magnet 104 and the sensor magnet 106 are spaced apart in the axial direction has been exemplified. In a modified example, the rotor magnet and the sensor magnet may be integrally configured. The rotor magnet portion and the sensor magnet portion may be integrally molded in the magnet portion molding process. In that case, the area (outer diameter) of the sensor magnet may be increased so that the magnetic sensor can reliably detect magnetic flux. Since the sensor magnet protrudes beyond the outer periphery of the rotor core, it becomes easier to injection mold the sensor magnet and the rotor magnet.

[0108] In each embodiment, a laminated core (laminated magnetic core) is exemplified as the core of the stator. In a modified example, a dust core or other core may be adopted. A dust core is also called a "powder core" and is obtained by powdering a soft magnetic material, coating the powder with a non-conductive resin or the like, kneading the powder with a resin binder, and compression molding and heating it.

[0109] In each embodiment, a configuration in which the drive circuit, control circuit, communication circuit, and power supply circuit are mounted on the underside of the circuit board has been illustrated, but the circuits to be mounted can be changed as appropriate. For example, the drive circuit and power supply circuit may be mounted, while the control circuit may be installed outside the motor-operated valve. In addition, each circuit may be mounted on the upper surface of the circuit board.

[0110] In each embodiment, a PM type stepping motor is used as the motor unit, but a hybrid type stepping motor may also be used. In the above embodiments, the motor unit is a three-phase motor, but it may be another type such as a two-phase, four-phase, or five-phase motor. The number of electromagnetic coils in the stator is not limited to three for the motor unit or six for the first body, and may be set appropriately according to the number of phases of the motor.

[0111] The motor-operated valve of each embodiment is preferably applied to a refrigeration cycle that uses a refrigerant such as an alternative fluorocarbon (HFC-134a) as a refrigerant, but can also be applied to a refrigeration cycle that uses a refrigerant with a high operating pressure such as carbon dioxide. In that case, an external heat exchanger such as a gas cooler is disposed in the refrigeration cycle instead of a condenser.

[0112] In each embodiment, the motor-operated valve is configured as an expansion valve, but it may be configured as an opening / closing valve or a flow control valve that does not have an expansion function.

[0113] In each embodiment, the motor-operated valve is applied to the refrigeration cycle of an automotive air conditioner, but the motor-operated valve can be applied to any air conditioner equipped with an electric expansion valve, not limited to vehicles. Also, the motor-operated valve can be configured to control the flow of a fluid other than a refrigerant.

[0114] The present embodiment is not limited to electric vehicles, but can be applied to various types of vehicles.

[0115] The sensor magnet 106 may be magnetized with four poles on both sides (one-sided valve body with two poles magnetized on both sides). The magnetic flux can be strengthened by reversing the polarity of the magnetic poles on the upper and lower sides. In this case, even if the rotor 60 is displaced in the valve closing direction and the distance between the sensor magnet 106 and the magnetic sensor 119 increases, the sensitivity of the magnetic sensor 119 can be maintained at a good level. [Explanation of symbols]

[0116] 1 motor-operated valve, 2 valve body, 3 motor unit, 5 body, 6 first body, 8 second body, 10 male thread, 12 seal housing, 14 seal ring, 16 concave fitting portion, 18 seal housing, 20 seal ring, 22 valve hole, 24 valve seat, 26 inlet port, 28 outlet port, 30 valve chamber, 32 operating rod, 34 valve body, 36 guide member, 38 male thread, 40 large diameter portion, 42 spring retainer, 44 spring retainer, 46 spring, 52 locking portion, 60 rotor, 62 rotating shaft, 64 stator, 66 can, 70 laminated core, 73 coil, 73a U-phase coil, 73b V-phase coil, 73c W-phase coil, 74 bobbin, 75 coil unit, 76 case, 77 cover, 78 stator unit, 79 Connector section, 80 seal housing section, 81 connection terminal, 82 seal ring, 90 stopper, 102 rotor core, 104 rotor magnet, 106 sensor magnet, 108 female screw, 109 screw feed mechanism, 110 reduced diameter section, 112 bottom section, 114 stopper, 116 spring, 117 terminal, 118 circuit board, 119 magnetic sensor, 120 slot, 122 salient pole, 124 slit, 140 annular groove, 144 annular groove, 200 motor-operated valve control device, 202 data processing section, 204 communication section, 206 reference information storage section, 208 rotor interface section, 210 receiving section, 212 transmitting section, 214 rotation instruction section, 216 rotation detection section, 218 rotation control section, Q initial position

Claims

1. It is connected to an electric valve that adjusts the valve opening by rotating the rotor. a rotation detection unit that detects a rotation angle of the rotor; a rotation control unit that moves the rotor toward a predetermined stop position by instructing a rotation speed and a rotation direction of the rotor; a reference information storage unit that stores a reference angle value indicating a rotation angle of the rotor at a reference position, The reference angle value is a unique value measured in advance for each of the motor-operated valves, the rotation control unit reads out the reference angle value from the reference information storage unit when controlling the movement of the rotor to the stop position; The motor-operated valve control device comprises: a control device for controlling a rotation speed of the rotor that is slowed down when a difference value between the read reference angle value and a rotation angle detected for the rotor is less than a first threshold value.

2. 2. The motor-operated valve control device according to claim 1, wherein, in the motor-operated valve, when the rotor reaches the reference position, rotation of the rotor is restricted.

3. The electric valve control device according to claim 1 or 2, characterized in that, after the rotor speed is reduced, the rotation control unit increases the rotation speed of the rotor when a difference value between the rotation angle detected for the rotor and the reference angle value becomes equal to or greater than the first threshold value.

4. A receiving unit for receiving an initialization command, The electric valve control device according to any one of claims 1 to 3, characterized in that, when the initialization command is received, the rotation control unit rotates the rotor in a first direction to reach the reference position, and then moves the rotor to the stop position, which is a position rotated from the reference position by a first rotation amount in a second direction opposite to the first direction.

5. 5. The electric valve control device according to claim 4, wherein the rotation control unit, after causing the rotor to reach the reference position, further moves the rotor to the stop position by instructing the rotor to rotate a second rotation amount in the first direction.

6. 6. The electric valve control device according to claim 1, wherein, when moving the rotor to the stop position, the rotation control unit rotates the rotor a third rotation amount in a direction opposite to the direction toward the stop position, and then rotates the rotor in the direction toward the stop position.

7. the rotation detection unit detects a rotation angle of the rotor each time a unit rotation amount of the rotor is specified; The electric valve control device according to any one of claims 1 to 6, characterized in that the rotation control unit detects the amount of rotation of the rotor based on the detected rotation angle, and determines the timing when the rotor reaches the reference position on the condition that a state in which the ratio of the detected amount of rotation to the unit amount of rotation is equal to or less than a second threshold value is detected a predetermined number of times or more.

8. A function for detecting the rotation angle of the rotor of the motor-operated valve; a function of moving the rotor toward a predetermined stop position by instructing a rotation speed and a rotation direction of the rotor; a function of storing a reference angle value indicating a rotation angle of the rotor at a reference position as a unique value measured in advance for each of the motor-operated valves; When controlling the movement of the rotor to the stop position, the reference angle value is read out; and a function of slowing down the rotational speed of the rotor when a difference value between the read reference angle value and the rotational angle detected for the rotor is less than a first threshold value.

9. It is connected to an electric valve that adjusts the valve opening by rotating the rotor. a rotation detection unit that detects a rotation angle of the rotor; a rotation control unit that sets an excitation pattern to indicate a rotation speed and a rotation direction of the rotor and moves the rotor toward a predetermined stop position; a reference information storage unit that stores a reference excitation value indicating a setting value of the excitation pattern at a reference position of the rotor, The reference excitation value is a unique value measured in advance for each of the motor-operated valves, the rotation control unit reads out the reference excitation value from the reference information storage unit when controlling the movement of the rotor to the stop position; When a difference value between the read reference excitation value and an excitation pattern set for the rotor is less than a predetermined threshold value, the rotation speed of the rotor is reduced.

Images