Electric valve control device and electric valve control program

Abstract

To easily retrieve a reference position (origin) specific to an electric valve.SOLUTION: An electric valve control device comprises: a rotation instruction unit for instructing an instruction angle to a stepping motor in such a manner that a step advances in a direction in which an axial motion is limited by a stop mechanism; a rotation detection unit for acquiring a sensed angle of a rotor from a sensor; a storage unit for holding the acquired sensed angle as record data; a stop detection unit for detecting a stop state of the rotor based on the acquired sensed angle; and an origin discrimination unit for repeating tracking of steps from a step, in which the stop state is detected, in the record data, determining whether or not a differential between a sensed angle in the step in which the stop state is detected and the sensed angle in the tracked step is greater than a predetermined value, and discriminating a step which is advanced from a step, in which the differential is greater than the predetermined value, in an advancing direction by a predetermined number as an origin of rotation of the rotor.SELECTED DRAWING: Figure 11

Description

[Technical Field]

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

[0002] Automotive air conditioning systems generally consist of a refrigeration cycle that includes a compressor, condenser, expansion device, evaporator, etc. The refrigeration cycle includes various control valves, such as an expansion valve, to control the flow of refrigerant. With the recent popularity of electric vehicles, motor-operated valves equipped with a motor as a drive unit are becoming increasingly popular.

[0003] Known examples of such motor-operated valves include one equipped with a magnetic sensor for detecting the valve opening degree (see, for example, Patent Document 1). A valve disc is attached to one end of an actuating rod that rotates together with the rotor, and a magnet (sensor magnet) is attached to the other end. A magnetic sensor is attached 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 valve element 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 known as the "origin," the rotor's rotation is restricted by a stopper (see, for example, Patent Document 2).

[0005] Even for motor-operated valves of the same type, there will be individual differences in the reference position. It is not appropriate to set a uniform reference position for each motor-operated valve. For this reason, when manufacturing motor-operated valves, it is necessary to detect and record the unique reference position for each motor-operated valve. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2018-135908 [Patent Document 2] Japanese Patent Publication No. 2020-204344 Summary of the Invention [Problem to be solved by the invention]

[0007] When the rotor's rotation is restricted by the stopper, the back electromotive force of the stepping motor that drives the rotor decreases. Therefore, one possible method for determining the reference position is to search for the point at which the back electromotive force of the stepping motor changes significantly while rotating the rotor in the valve closing direction. In this case, rotating the rotor at high speed is undesirable because a strong impact is applied to the stopper at the reference position. On the other hand, when rotating the rotor at low speed, it becomes difficult to detect the change in back electromotive force. Furthermore, if the rotor's movement is restricted not by the stopper but by foreign matter such as metal chips, the reference position may be incorrectly recognized.

[0008] A primary object of the present invention is to provide a technique for appropriately searching for a reference position (origin) specific to a motor-operated valve. [Means for solving the problem]

[0009] In one aspect of the present invention, an electric valve control device controls an electric valve having a stepping motor that rotates a rotor, a first mechanism that converts the rotational motion of the rotor into axial motion of a valve disc, a second mechanism that restricts the axial motion of the valve disc, and a sensor that measures the angle of the rotor to obtain a sensed angle, and is equipped with a rotation instruction unit that instructs the stepping motor to a command angle so that the axial motion progresses one step at a time in the direction in which the axial motion is restricted by the second mechanism, a rotation detection unit that acquires the sensed angle of the rotor from the sensor for each step, a memory unit that stores the acquired sensed angle for each step as recorded data, a stop detection unit that detects a stopped state of the rotor due to restriction of the axial motion for each step based on the acquired sensed angle, and an origin determination unit that repeatedly traces back steps in the recorded data starting from the step where the stopped state was detected, determines whether the difference between the sensed angle at the step where the stopped state was detected and the sensed angle at the step that was traced back is greater than a predetermined value, identifies the step where the difference is greater than the predetermined value, and determines the step a predetermined number of steps forward from the identified step in the direction of progression as the origin of rotor rotation.

[0010] In another aspect of the present invention, an electric valve control device controls an electric valve having a stepping motor that rotates a rotor, a mechanism that converts the rotational motion of the rotor into axial motion of the valve body, and a sensor that measures the angle of the rotor to obtain a sensed angle, and comprises a rotation instruction unit that instructs the stepping motor to a specified angle so as to proceed one step at a time, a rotation detection unit that acquires the sensed angle of the rotor from the sensor for each step, a memory unit that stores the acquired sensed angle for each step as recorded data, a step-out detection unit that detects a step-out state of the rotor due to restriction of axial motion based on the acquired sensed angle for each step, and a trigger position discrimination unit that repeatedly goes back in the recorded data from the step where the step-out state was detected, determines whether the difference between the sensed angle at the step where the step-out state was detected and the sensed angle at the step that went back is greater than a predetermined value, identifies the step where the difference is greater than the predetermined value, and determines the step a predetermined number of steps in the direction of progression from the identified step as the step-out trigger position.

[0011] In one aspect of the present invention, an electric valve control program causes a computer that controls an electric valve having a stepping motor that rotates a rotor, a first mechanism that converts the rotational motion of the rotor into axial motion of a valve disc, a second mechanism that restricts the axial motion of the valve disc, and a sensor that measures the angle of the rotor to obtain a sensed angle to perform the following functions: instructing the stepping motor to specify an angle so that the axial motion progresses step by step in the direction in which the axial motion is restricted by the second mechanism; obtaining the sensed angle of the rotor from the sensor for each step; storing the obtained sensed angle for each step as recorded data; detecting a stopped state of the rotor due to restriction of the axial motion based on the obtained sensed angle for each step; and repeatedly tracing back steps in the recorded data starting from the step in which the stopped state was detected, determining whether the difference between the sensed angle at the step in which the stopped state was detected and the sensed angle at the step that was traced back is greater than a predetermined value, identifying the step in which the difference is greater than the predetermined value, and determining the step a predetermined number of steps forward from the identified step in the forward direction as the origin of rotor rotation.

[0012] In another aspect of the present invention, an electric valve control program causes a computer controlling an electric valve having a stepping motor that rotates a rotor, a mechanism that converts the rotational motion of the rotor into axial motion of the valve body, and a sensor that measures the angle of the rotor to obtain a sensed angle to perform the following functions: instructing the stepping motor to indicate a command angle so as to proceed step by step; obtaining the sensed angle of the rotor from the sensor for each step; storing the obtained sensed angle for each step as recorded data; detecting a state of out-of-step of the rotor due to restriction of axial motion based on the obtained sensed angle for each step; and repeatedly tracing back steps in the recorded data starting from the step where the out-of-step state was detected, determining whether the difference between the sensed angle at the step where the out-of-step state was detected and the sensed angle at the step that was traced back is greater than a predetermined value, identifying the step where the difference is greater than the predetermined value, and determining the step a predetermined number of steps forward from the identified step as the trigger position for out-of-step.

[0013] In another aspect of the present invention, an electric valve control device controls an electric valve having a stepping motor that rotates a rotor, a first mechanism that converts the rotational motion of the rotor into axial motion of a valve body, a second mechanism that restricts the axial motion of the valve body, and a sensor that measures the angle of the rotor to obtain a sensed angle, and comprises: a rotation instruction unit that instructs the stepping motor to specify an angle so as to progress one step at a time in the direction in which the axial motion is restricted by the second mechanism; a rotation detection unit that acquires the sensed angle of the rotor from the sensor for each step; a memory unit that stores the sensed angle acquired for each step as recorded data; a stop detection unit that detects a stopped state of the rotor due to restriction of the axial motion for each step based on the sensed angle acquired; and an origin determination unit that identifies a step to be determined in the recorded data according to the order in which the steps progress, determines whether the difference between the sensed angle at the step in which the stopped state was detected and the sensed angle at the step to be determined is less than or equal to a predetermined value, and determines the step to be determined first to have a difference less than or equal to the predetermined value as the origin of rotor rotation.

[0014] In another aspect of the present invention, an electric valve control device controls an electric valve having a stepping motor that rotates a rotor, a mechanism that converts the rotational motion of the rotor into axial motion of the valve body, and a sensor that measures the angle of the rotor to obtain a sensed angle, and comprises: a rotation instruction unit that instructs the stepping motor to an instructed angle so as to progress one step at a time; a rotation detection unit that acquires the sensed angle of the rotor from the sensor for each step; a memory unit that stores the acquired sensed angle for each step as recorded data; a step-out detection unit that detects a step-out state of the rotor due to restriction of axial motion based on the acquired sensed angle for each step; and a trigger position discrimination unit that identifies a step to be judged in accordance with the order of step progression in the recorded data, determines whether the difference between the sensed angle at the step where the step-out state was detected and the sensed angle at the step to be judged is less than a predetermined value, and discriminates the step to be judged that is first judged to have a difference less than the predetermined value as the trigger position for step-out.

[0015] In another aspect of the present invention, an electric valve control program causes a computer that controls an electric valve having a stepping motor that rotates a rotor, a first mechanism that converts the rotational motion of the rotor into axial motion of a valve disc, a second mechanism that restricts the axial motion of the valve disc, and a sensor that measures the angle of the rotor to obtain a sensed angle to perform the following functions: instructing the stepping motor to specify an angle so as to proceed step by step in the direction in which the axial motion is restricted by the second mechanism; acquiring the sensed angle of the rotor from the sensor for each step; storing the acquired sensed angle for each step as recorded data; detecting a stopped state of the rotor due to restriction of the axial motion based on the acquired sensed angle for each step; identifying a step to be judged in accordance with the order in which the steps are progressed in the recorded data, determining whether the difference between the sensed angle at the step in which the stopped state was detected and the sensed angle at the step to be judged is less than or equal to a predetermined value; and determining the step to be judged that is first judged to have a difference less than or equal to the predetermined value as the origin of rotor rotation.

[0016] In another aspect of the present invention, an electric valve control program causes a computer controlling an electric valve having a stepping motor that rotates a rotor, a mechanism that converts the rotational motion of the rotor into axial motion of the valve body, and a sensor that measures the angle of the rotor to obtain a sensed angle to perform the following functions: instructing the stepping motor to specify a command angle so as to progress one step at a time; obtaining the sensed angle of the rotor from the sensor for each step; storing the obtained sensed angle for each step as recorded data; detecting a step-out state of the rotor due to restriction of axial motion based on the obtained sensed angle for each step; identifying a step to be judged in accordance with the order of step progression in the recorded data, determining whether the difference between the sensed angle at the step where the step-out state was detected and the sensed angle at the step to be judged is less than a predetermined value, and identifying the step to be judged that is first judged to have a difference less than the predetermined value as the trigger position for step-out. [Effects of the Invention]

[0017] According to the present invention, it becomes easier to appropriately search for a reference position (origin) specific to a motor-operated valve. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a cross-sectional view illustrating a motor-operated valve according to an embodiment. [Figure 2] FIG. 2 is a diagram illustrating a configuration of a stator and its surroundings. [Figure 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. [Figure 5] FIG. 2 is a plan view of a sensor magnet. [Figure 6] 10 is a graph showing the relationship between the sensor value of the sensor magnet and the sensing angle. [Figure 7] 10 is a graph showing the relationship between the angle value (duty ratio) and the step. [Figure 8] FIG. 2 is a schematic diagram of the range of movement of the rotor. [Figure 9] 10 is a graph showing the transition of steps and rotor angles in the origin detection operation. [Figure 10] Figure 10(A) is a graph showing the transition of steps and rotor angle in ideal behavior, and Figure 10(B) is a graph showing the transition of steps and rotor angle in realistic behavior. [Figure 11] Fig. 11(A) is a graph for explaining a method for determining the origin on the assumption of ideal behavior, and Fig. 11(B) is a graph for explaining a method for determining the origin on the assumption of realistic behavior. [Figure 12] Fig. 12(A) is a graph showing an example where the error range does not cross the angle boundary, Fig. 12(B) is a graph showing an example where the upper side of the error range crosses the angle boundary, and Fig. 12(C) is a graph showing an example where the lower side of the error range crosses the angle boundary. [Figure 13] This is a truth table for determining whether an error is within or outside the error range. [Figure 14]FIG. 2 is a functional block diagram of the motor-operated valve control device. [Figure 15] 10 is a flowchart showing a main processing step. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. For convenience, the following description may refer to the positional relationship of each structure based on the illustrated state. In the following embodiments and their modifications, substantially identical components will be designated by the same reference numerals, and their description will be omitted where appropriate.

[0020] FIG. 1 is a cross-sectional view showing a motor-operated valve according to an embodiment. The motor-operated valve 1 is applied to the refrigeration cycle of an automotive 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 to send it out in the form of mist, and an evaporator that evaporates the mist of refrigerant and cools the air inside the vehicle cabin using the latent heat of evaporation. The motor-operated valve 1 functions as an expansion valve for this refrigeration cycle.

[0021] 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"). The second body 8 is provided with a valve seat 24, so 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.

[0022] The first body 6 is a stepped cylinder whose outer diameter tapers in stages downward. The outer diameter of the upper end of the first body 6 is slightly tapered, forming a step-like locking portion 52. 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 pipes extending from the condenser side and pipes connected to the evaporator, but detailed explanations of these will be omitted. 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.

[0023] A circular hole-shaped recessed fitting portion 16 is provided in the lower part of the first body 6. The second body 8 is cylindrical with a bottom, and its upper part is press-fitted into the recessed fitting portion 16. A seal accommodating portion 18 consisting of an annular groove is formed in the outer peripheral surface of the lower part 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 axially penetrate the bottom part of the second body 8, and a valve seat 24 is formed at the upper opening of the valve hole 22. An inlet port 26 is provided in the side part of the second body 8, and an outlet port 28 is provided in the lower part. A valve chest 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 via the valve chest 30.

[0024] An actuation rod 32 extending from the rotor 60 of the motor unit 3 is inserted into the body 5. The actuation rod 32 passes through the valve chamber 30. The actuation rod 32 is obtained by cutting a rod made of a non-magnetic metal, and a needle-shaped valve element 34 is provided integrally at the bottom of the actuation rod 32. The valve element 34 opens and closes the valve by attaching and detaching from the valve seat 24 from the valve chamber 30 side.

[0025] A guide member 36 is erected at the top center of the first body 6. The guide member 36 is obtained by cutting a tube made of a non-magnetic metal into a stepped cylindrical shape, and a male thread 38 is formed on the outer peripheral surface of the axial center portion of the guide member 36. The lower end of the guide member 36 has a large diameter, and this large diameter portion 40 is press-fitted into the top center of the first body 6 and fixed coaxially. The guide member 36 supports the actuation rod 32 axially slidably with its inner peripheral surface, and rotatably and slidably supports the rotary shaft 62 of the rotor 60 with its outer peripheral surface.

[0026] A spring retainer 42 is provided on the operating rod 32 slightly above the valve element 34, and a spring retainer 44 is also provided at the bottom of the guide member 36. A spring 46 (which functions as a "biasing member") is interposed between the spring retainers 42, 44 to bias the valve element 34 in the valve closing direction.

[0027] 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 arranged inside the can 66 and the stator 64 arranged 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-pressure space (external space) where the pressure of the refrigerant does not act.

[0028] The can 66 is made of a non-magnetic metal (SUS in this embodiment), and is assembled coaxially with its lower portion fitted onto the upper end of the first body 6. The insertion depth of the can 66 is limited by its lower end being locked by the locking portion 52. The body 5 and the can 66 are fixed and sealed by applying a full-circle welding (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 pressure space.

[0029] The stator 64 is configured by arranging multiple salient poles at equal intervals on the inner periphery of a laminated core 70. The laminated core 70 is configured by laminating annular cores in the axial direction. A bobbin 74, to which a coil 73 (electromagnetic coil) is attached, is attached to each salient pole. These coils 73 and bobbins 74 form a "coil unit 75." In this embodiment, three coil units 75 for supplying three-phase current are provided at 120-degree intervals around the central axis of the laminated core 70 (details will be described later).

[0030] 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 obtained 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 will also be referred to as a "stator unit 78."

[0031] The stator unit 78 has a hollow structure and is assembled to the body 5 with the can 66 inserted coaxially. 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 external atmosphere (water, etc.) from entering the gap between the can 66 and the stator 64.

[0032] The rotor 60 includes a cylindrical rotor core 102 attached to the rotating shaft 62, a rotor magnet 104 attached to the outer peripheral surface of the rotor core 102, and a sensor magnet 106 attached to 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) with multiple poles in its circumferential direction. The sensor magnet 106 is also magnetized (magnetized) with multiple poles. The rotor magnet 104 and the sensor magnet 106 are obtained by magnetizing magnet portions integrally molded with the rotor core 102 in a post-process, and details of this will be described later.

[0033] 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 is engaged with the male thread 38 of the guide member 36. A screw feed mechanism 109 using these threads converts the rotational motion of the rotor 60 into axial motion of the actuation rod 32. This causes the valve element 34 to move (lift) in the axial direction, i.e., in the opening and closing direction of the valve portion. The screw feed mechanism 109 is an example of a "first mechanism that converts the rotational motion of the rotor 60 into axial motion of the valve element 34."

[0034] The upper part of the actuating rod 32 has a reduced diameter, and the reduced diameter portion 110 penetrates the bottom portion 112 of the rotary shaft 62. An annular stopper 114 is fixed to the tip of the reduced diameter portion 110. Meanwhile, a spring 116 that urges the actuating rod 32 downward (i.e., in the valve closing direction) is interposed between the base end of the reduced diameter portion 110 and the bottom portion 112. With this configuration, when the valve is opened, the actuating rod 32 is displaced integrally with the rotor 60 with the stopper 114 engaged with the bottom portion 112. Meanwhile, when the valve is closed, the spring 116 is compressed by the reaction force that the valve element 34 receives from the valve seat 24. At this time, the elastic reaction force of the spring 116 can press the valve element 34 against the valve seat 24, improving the seating performance (valve closing performance) of the valve element 34.

[0035] 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 that function as a control unit and a communication unit are mounted on the underside of the circuit board 118. Specifically, a drive circuit for driving the motor, a control circuit (microcomputer) that outputs control signals 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 on the underside of the circuit board 118. 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.

[0036] 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 disc 34, and therefore the valve opening, based on the amount of displacement of the rotor 60.

[0037] 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 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 the side wall of the case 76. A connector section 79 is integrally provided on the side of the case 76, and the connection terminals 81 are arranged inside the connector section 79.

[0038] A stopper 90 is formed below the rotor 60. The configuration of the stopper 90 is known, as shown in Patent Document 2. When the operating rod 32 reaches the valve-closed position, an elastic reaction force is applied to the rotor 60 by a spring 116, stably maintaining the valve closed. Ultimately, the stopper 90 abuts against a protrusion (locking portion) (not shown) formed as part of the guide member 36, completely restricting rotation of the rotor 60 in the valve-closing direction. Hereinafter, the step when the stopper 90 abuts against the protrusion will be referred to as the "origin" of the step. In addition, in this embodiment, the valve element 34 will be in the "reference position" at the origin of the step.

[0039] Figure 2 is a diagram showing the configuration of the stator 64 and its surroundings. Figure 2(A) corresponds to the cross section taken along the line AA in Figure 1, and is a cross section of the stator unit 78. Figure 2(B) shows only the stator 64 (before resin molding). For reference, Figure 2(A) also shows the can 66 and rotor 60 (see the two-dot chain line).

[0040] Because 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-120c (collectively referred to as "slots 120" when no distinction is made) are provided at 120-degree intervals around the axis L on the inner periphery of the laminated core 70. Each slot 120 has salient poles 122a-122c (collectively referred to as "salient poles 122") that protrude radially inward from the center thereof, 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 with a U-shaped cross section are also formed between adjacent slots 120, optimizing the magnetic path.

[0041] 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 corresponding to the male thread, but the number of poles can be set appropriately.

[0042] Next, the configuration of the magnets in the rotor 60 will be described in detail. 3A and 3B are diagrams showing the configuration of the rotor 60. FIG. 3A is a perspective view, FIG. 3B is a front view, FIG. 3C is a plan view, and FIG. 3D is a cross-sectional view taken along the line B-B in FIG. 3C. 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 not shown in the diagram.

[0043] The rotor 60 has a rotor magnet 104 along the outer peripheral 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 has ten magnetized poles on its outer peripheral surface (FIGS. 3(B) and 3(C)). On the other hand, the sensor magnet 106 is annular and has two magnetized poles on its plane.

[0044] 3(D), the inner peripheral surface of rotor magnet 104 is fitted into annular groove 140, and the lower surface of sensor magnet 106 is fitted 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.

[0045] Based on the above configuration, we will now explain how the magnetic sensor 119 detects the rotation angle of the rotor 60. In the following, the up and down direction in Fig. 1 will be referred to as the "opening / closing direction" or "up and down direction."

[0046] 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 field lines are generated from the north to south direction 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 field lines 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 field lines (described in detail below). 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 / closing direction.

[0047] FIG. 5 is a plan view of the sensor magnet 106. As shown in FIG. 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.

[0048] 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.

[0049] FIG. 6 is a graph showing the relationship between the sensor value of the sensor magnet 106 and the sensing angle. The horizontal axis represents the rotation angle θ of the sensor magnet 106, which is the measurement target of the magnetic sensor 119 (hereinafter, sometimes referred to as the "sensing angle"). The vertical axis represents the sensor value of the magnetic sensor 119. In this example, the sensor value is an arctangent value. As shown in FIG. 6, the magnetic sensor 119 detects a sensor value that exhibits a sawtooth waveform corresponding to the sensing angle. The magnetic sensor 119 converts the sensor value, which is an analog signal, into a pulse duty ratio using PWM (Pulse Width Modulation) and outputs a current representing the modulated digital signal. At this time, the sensor value is normalized to a "lower limit value DA to upper limit value TA" to determine the pulse duty ratio. The lower limit value DA and upper limit value TA can be set arbitrarily. The lower limit value DA may be 0. Hereinafter, the pulse duty ratio will be referred to as the "angle value." The control circuit can determine the actual rotor angle (sensing angle) based on the duty ratio (angle value) read from the pulse of the digital signal in accordance with the specifications of the magnetic sensor 119.

[0050] FIG. 7 is a graph showing the relationship between the angle value (duty ratio) and the step. In this embodiment, when the valve disc 34 is moved from the highest point to the lowest point, 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 coils 73 to change the magnetic field direction of each coil 73, thereby rotating the rotor 60. In this embodiment, the control circuit rotates the rotor 60 in increments of u1 degrees (as will be described in detail later). Hereinafter, this unit rotation amount will be referred to as a "step." Since 360 ​​degrees x 4 rotations ÷ u1 degrees = 1440 / u1 = SM4, the control circuit instructs the rotor 60 to rotate a total of SM4 steps within the operating range of the actuating rod 32. Corresponding to the four rotations of the rotor 60, the angle value changes four times between DA and TA.

[0051] Step 0 corresponds to the origin, and step n represents the nth step counting from the origin. SM1 in the figure represents the order of steps when the mechanical angle makes one revolution, SM2 represents the order of steps when the mechanical angle makes two revolutions, SM3 represents the order of steps when the mechanical angle makes three revolutions, and SM4 represents the order of steps when the mechanical angle makes four revolutions. The mechanical angle refers to the angle of a rotating body such as rotor 60 in real space.

[0052] The control circuit applies a predetermined level of drive current to the U-phase coil 73a. At this time, similar drive currents of predetermined levels are also applied to the V-phase coil 73b and the W-phase coil 73c. ​​By applying drive current to each coil 73, the magnetic field in the coil 73 is changed, causing the rotor 60 to rotate. A combination of drive current values ​​applied to each of the U-phase coil 73a, the V-phase coil 73b, and the W-phase coil 73c is called an "excitation pattern." In this embodiment, there are N types of excitation patterns. Changing from a certain excitation pattern P1 to the adjacent excitation pattern P2 corresponds to "one step" of rotation, or in other words, a rotation instruction for a unit rotation amount.

[0053] By changing the excitation pattern, in other words, by changing the excitation pattern step by step, the command angle α (ideal rotor angle) is controlled. In synchronization with the change in command angle α, 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, and determines whether the sensed angle θ (actual rotor angle) is tracking the command angle α. The state in which the sensed angle θ tracks the command angle α is called "synchronization," and the state in which the sensed angle θ cannot track the command angle α is called "loss of synchronization."

[0054] A pattern ID is assigned to each of the N types of excitation patterns. The drive current values ​​for the U-phase coil 73a, V-phase coil 73b, and W-phase coil 73c in the excitation pattern with pattern ID N1 (hereinafter referred to as "excitation pattern (N1)") are IU(N1), IV(N1), and IW(N1), respectively. In other words, the excitation pattern (N1) refers to the combination of [IU(N1), IV(N1), IW(N1)]. The drive currents IU(N1), IV(N1), and IW(N1) generate magnetic fields in the coils 73, guiding the rotor 60 to the command angle α corresponding to the excitation pattern (N1).

[0055] N types of pattern IDs correspond to N steps of one revolution of the electrical angle. The electrical angle is a theoretical value in which N pattern IDs are evenly allocated in the range of 0 to 360 degrees. Each step n from the origin to the top is cyclically associated with a pattern ID in sequence. For example, a pattern ID is determined as the remainder when n is divided by N. Furthermore, consecutive pattern IDs correspond to continuously changing excitation patterns.

[0056] When the control circuit moves from step n to step n+1, it switches from excitation pattern (N1) to excitation pattern (N1+1). This changes the magnetic field generated by each coil 73 with the drive current values ​​[IU(N1+1), IV(N1+1), IW(N1+1)], causing the rotor 60 to rotate upward by a unit rotation. Conversely, when the control circuit moves from step n to step n-1, it switches from excitation pattern (N1) to excitation pattern (N1-1). This changes the magnetic field generated by each coil 73 with the drive current values ​​[IU(N1-1), IV(N1-1), IW(N1-1)], causing the rotor 60 to rotate downward by a unit rotation.

[0057] In the case of the rotor 60 having the structure shown in FIG. 3, the rotor magnet 104 has five pairs of north and south poles, so one rotation of the rotor 60 (360 degrees of mechanical angle) results in five electrical rotations. In other words, one electrical rotation corresponds to 72 degrees of mechanical angle. Furthermore, one electrical rotation includes N steps, so the mechanical angle rotated with one step change is u1 = 72 / N degrees. Furthermore, as described in relation to FIG. 7, if the rotor 60 rotates four times while moving the valve disc 34 from the highest point to the origin, the entire movement will advance 4 × 5 × N steps. In other words, SM4 shown in FIG. 7 is 4 × 5 × N. Similarly, SM1 is 5 × N, SM2 is 2 × 5 × N, and SM3 is 3 × 5 × N.

[0058] 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)." When the motor-operated valve 1 is manufactured, the origin information (reference information) specific to the motor-operated valve 1 is recorded in the non-volatile memory of the circuit board 118. Then, the control circuit adjusts the amount of movement of the operating rod 32, i.e., the valve opening degree of the motor-operated valve 1, using step n that uses the origin (valve closed position) as a reference.

[0059] FIG. 8 is a schematic diagram of the range of movement of the rotor 60. As shown in FIG. In Figure 8, the right direction indicates the valve opening direction (upward direction) of the rotor 60, and the left direction indicates the valve closing direction (downward direction). The origin of step 0 is the limit position where the stopper 90 restricts rotation and the rotor 60 cannot further rotate downward. Step M is the valve opening point where the rotor 60 rotates upward. The value of M may be a predetermined common value or a unique value that differs for each motor-operated valve 1. If a unique value is used, the value of M, which indicates the step of the valve opening point, is stored in the non-volatile memory of the circuit board 118. Between the origin and the valve opening point, the elastic reaction force of the spring 116 presses the valve disc 34 against the valve seat 24, maintaining the valve closed state. When the rotor 60 continues to rotate upward from the origin 0 and passes the valve opening point M, the valve disc 34 separates from the valve seat 24, entering the valve open state. If the rotor 60 continues to rotate upward after passing the valve opening point, the valve opening gradually increases, and the flow rate from the inlet port 26 to the outlet port 28 increases.

[0060] This embodiment relates to a technique for detecting a specific origin by the motor-operated valve 1 after assembly including the motor-operated valve control device realized by the circuit board 118 has been completed, mainly during the manufacturing stage.

[0061] FIG. 9 is a graph showing the transition of steps and rotor angles in the origin detection operation. When starting to detect the origin, the step corresponding to the origin is naturally unknown, and there is no origin information yet. The position (step) shown here does not refer to a step based on the origin as explained in Figure 8, but rather refers to a provisional step.

[0062] The starting point 500 indicates the position (step) at which rotational movement for detecting the origin begins, and the rotor angle at that position. The rotor angle at the starting point 500 can be measured using an angle sensor. The illustrated ideal behavior line 502 indicates the relationship between the position (step) and the ideal rotor angle when the rotor 60 ideally operates in accordance with the operation of the stepping motor, starting from the starting point 500. In other words, it can be said to indicate the relationship between the step and the command angle α commanded by the excitation pattern corresponding to that step. When no force is applied to suppress the movement of the rotor 60, and the rotor angle is achieved as designed by the excitation pattern corresponding to the step, a measurement point will appear on the ideal behavior line 502.

[0063] In the figure, an upper tuning limit line 504 is shown above the ideal behavior line 502, and a lower tuning limit line 506 is shown below the ideal behavior line 502. The range between the lower tuning limit line 506 and the upper tuning limit line 504 is the tuning range 505. The tuning range 505 is the range within which the stepping motor is estimated to be in sync. In other words, if the rotor angle (sensed angle) measured at a certain step is within the tuning range 505, it can be estimated that the stepping motor is in an tuned state at that step. The range outside the tuning range 505 is the out-of-step range. The out-of-step range is the range within which an out-of-step state of the stepping motor is detected. In other words, if the rotor angle measured at a certain step is within the out-of-step range, it can be estimated that the stepping motor is in an out-of-step state at that step.

[0064] In the reverse rotation region 507, the upper tuning limit line 504 is below the lower tuning limit line 506. Therefore, the range between the upper tuning limit line 504 and the lower tuning limit line 506 is the out-of-step range, and the range below the upper tuning limit line 504 and above the lower tuning limit line 506 is the tuning range 505.

[0065] The arrows in the figure indicate the direction of transition in the origin detection operation. Specifically, the rotor 60 is rotated so that the valve element 34 moves toward the position where the stopper 90 abuts against the guide member 36 (more precisely, the protrusion of the guide member 36). In this example, the rotor 60 is rotated downward. The stepping motor rotates one step at a time. The operation of the motor-operated valve 1 when it advances one step is called a unit operation.

[0066] The motor-operated valve control device records the rotor angle (sensed angle) measured for each unit operation. The recording of the rotor angle will be described in detail later.

[0067] Furthermore, for each unit operation, the motor-operated valve control device determines, based on the measured rotor angle (sensed angle), whether the rotor 60 has come to a stop as a result of the stopper 90 coming into contact with the guide member 36. Immediately after the stopper 90 actually comes into contact with the guide member 36, it is difficult to determine from the measured rotor angle (sensed angle) that the rotor has come to a stop. This is because, even if the measured rotor angle (sensed angle) deviates from the ideal rotor angle (command angle), it is impossible to determine whether the rotor is in a stopped state or is merely a deviation that can occur during rotation. Therefore, the motor-operated valve control device determines that the rotor 60 is in a stopped state when the actual rotor angle (sensed angle) deviates to a certain extent from the ideal rotor angle (command angle).

[0068] The motor-operated valve control device detects the stopped state of the rotor 60 by applying logic for determining out-of-step. The stop mechanism (an example of a "second mechanism for limiting the axial movement of the valve disc"), in which the stopper 90 abuts against the guide member 36 to limit the axial movement of the valve disc 34, can also be said to be a mechanism that causes out-of-step. Therefore, it is natural in a sense that the stop of the rotor 60 caused by the stop mechanism can be detected using the same logic as for determining out-of-step. Therefore, it is clearly possible to detect the stopped state of the rotor 60 by a method for determining out-of-step other than the method exemplified here. Furthermore, the application of such a method for determining out-of-step is fully conceivable as a modified example of this embodiment.

[0069] FIG. 10(A) is a graph showing the transition of steps and rotor angles in ideal behavior. Here, it is assumed that there is no fluctuation in the rotor angle during rotation, no error in the magnetic sensor 119, etc.

[0070] As the step progresses in the valve closing direction, measurement points 415, 414, ..., 405, which indicate the step and rotor angle, appear from the upper right to the lower left in the figure. Rotor 60 rotates from measurement point 415 to measurement point 405, and these measurement points overlap with ideal behavior line 502.

[0071] Measurement point 404 represents the step at which stopper 90 comes into contact with guide member 36 and rotor 60 stops rotating. The steps proceed further in the order of measurement point 404, measurement point 403, measurement point 402, and measurement point 401, but the rotor angle does not change during this time. From measurement point 404 to measurement point 401, the deviation from the ideal rotor angle on ideal behavior line 502 is small, and remains within synchronization range 505, so it is not yet determined that the rotor has stopped.

[0072] When it reaches measurement point 400, it goes outside the synchronization range 505. In other words, since measurement point 400 has moved into the out-of-step range, it is determined that rotor 60 has already stopped. At this stage, the motor-operated valve control device stops the progress of the steps. Through the processing up to this point, the rotor angles at measurement points 415 to 400 have been recorded.

[0073] The motor-operated valve control device uses the recorded rotor angle data to identify the measurement point 404 when the rotor 60 actually stops. A method for identifying the step when the rotor 60 stops will be described later.

[0074] FIG. 10(B) is a graph showing the transition of steps and rotor angles in realistic behavior. Here, it is assumed that there is a deviation in the rotor angle during rotation, an error in the magnetic sensor 119, and the like.

[0075] In reality, fluctuations in the rotor angle during rotation can occur due to foreign matter getting caught, vibrations or external forces acting on the motor-operated valve 1. Therefore, the rotor angle during rotation (sensed angle) can deviate slightly from the ideal rotor angle (indicated angle), as shown by measurement points 314 to 305.

[0076] Furthermore, since errors occur in the measurements made by the magnetic sensor 119, the rotor angle (sensed angle) in the stopped state is not constant, as shown by measurement points 304 to 300.

[0077] FIG. 11(A) is a graph for explaining a method for determining the origin, assuming ideal behavior. Figure 11(A) is an enlarged view of a portion of Figure 10(A). In this example, the motor-operated valve control device identifies measurement point 404 where rotor 60 actually stopped, based on measurement point 400 where rotor 60 was determined to be in a stopped state.

[0078] To identify the measurement point 404 where the rotor 60 actually stopped, the motor-operated valve control device determines the previous measurement point 405, i.e., the measurement point 405 where the rotor 60 was last in a rotating state. Specifically, by comparing the rotor angle (sensed angle) at the measurement point 400 where the rotor 60 was judged to be in a stopped state with the rotor angle (sensed angle) at the measurement point 405, it can be determined that the measurement point 405 was in the last rotating state. If the difference in the rotor angles (sensed angles) is large, this means that the rotor 60 was rotating, regardless of an error in the magnetic sensor 119.

[0079] The "error angle" refers to the maximum deviation of the rotor angle (sensed angle) that appears as a measurement error of the magnetic sensor 119. The error angle is used as a threshold (an example of a "predetermined value") for determining the difference in the rotor angle (sensed angle) when determining the step (measurement point 405) that was in the last rotation state.

[0080] The rotor angle (sensed angle) at the measurement point 400 where it is determined that the rotor 60 is in a stopped state is represented as Y(0). An error range 515 is set with Y(0) as the median. The maximum angle Ymax of the error range 515 is the angle obtained by adding the error angle to Y(0). The minimum angle Ymin of the error range 515 is the angle obtained by subtracting the error angle from Y(0). The error range 515 indicates the range of error of the magnetic sensor 119 based on the rotor angle (sensed angle) at the measurement point where it is determined that the rotor 60 is in a stopped state. In other words, the error range 515 is a reference range for determining whether the measured rotor angle (sensed angle) corresponds to a stopped state. The reference range is the range that corresponds to a stopped state, and the error range 515 is an example of the reference range.

[0081] FIG. 11B is a graph for explaining a method for determining the origin on the assumption of realistic behavior. The rotor angles (sensed angles) measured at measurement points 300 to 304 where the rotor 60 is stopped contain measurement errors by the magnetic sensor 119. Therefore, in reality, the values ​​fluctuate slightly up and down in the diagram. However, all of measurement points 300 to 304 fall within an error range 515. On the other hand, measurement point 305, which was rotating, is outside the error range 515. Focusing on this point, the motor-operated valve control device traces the step progression from the record of measurement point 300 back to determine whether the rotor angle (sensed angle) at each measurement point falls within the error range 515. Then, it finds measurement point 305 that indicates a rotor angle (sensed angle) that does not fall within the error range 515. The measurement point 305 found first in the tracing back order corresponds to the last step in which the rotor was actually rotating. The measurement point 305 that is first determined to be outside the error range 515 corresponds to the "most recent step in which the difference in rotor angle (sensed angle) is greater than a predetermined value (in this example, the error angle)."

[0082] The motor-operated valve control device identifies the measurement point 305 where it is determined that the rotor angle (sensed angle) is outside the error range 515 first in retrospective order, and then determines that the next measurement point 304 in the order of step progression from that measurement point 305 is the step where the rotor 60 actually stopped. This step is then determined as the origin for stopping by the stop mechanism.

[0083] In principle, this is how origin detection is possible. However, there are some points to keep in mind when numerically processing the rotor angle (sensible angle) when expressing it as a parameter between 0 and 360 degrees during implementation. This is the issue of how to handle the boundary between 360 degrees and 0 degrees.

[0084] Angle (deg) expressed in the range of 0 to 360 is a type of parameter that cycles in a predetermined range (360 in this example). If error range 515 straddles the boundary between 360 (deg) and 0 (deg), it cannot be handled by a simple comparison of magnitude.

[0085] FIG. 12(A) is a graph showing an example in which the error range 515 does not cross the boundary of the angle. If the sum of the rotor angle (sensible angle): Y(0) of measurement point 300a, where rotor 60 is judged to be in a stopped state, plus the error angle does not exceed 360 (deg), and if the difference value obtained by subtracting the error angle from Y(0) is not a negative value, then the relationship of maximum angle Ymax of error range 515 > minimum angle Ymin of error range 515 holds, as shown in the figure.

[0086] In this case, if the rotor angles (sensible angles) of the traced measurement points 301a to 305a are represented by Y(n), the events can be organized as follows: Note that n represents the number of traces, which in this example represents 1 to 5. (Event 1) An event in which Y(n) is smaller than Ymin and greater than Ymax does not occur. (Event 2) If Y(n) is smaller than Ymin and smaller than Ymax, then Y(n) is outside the error range 515. (Event 3) If Y(n) is greater than Ymin and greater than Ymax, then Y(n) is outside the error range 515. (Event 4) If Y(n) is greater than Ymin and less than Ymax, then Y(n) is within the error range 515.

[0087] FIG. 12(B) is a graph showing an example in which the upper side of the error range 515 crosses the boundary of the angle. If the sum of the rotor angle (sensible angle): Y(0) at measurement point 300b where it is determined that rotor 60 is in a stopped state and the error angle exceeds 360 (deg), the value obtained by subtracting 360 (deg) from that sum, that is, a value slightly larger than 0, indicates the maximum angle Ymax of error range 515. In this case, as shown in the figure, the relationship of maximum angle Ymax of error range 515<minimum angle Ymin of error range 515 holds.

[0088] In this case, the events can be summarized as follows: (Event 5) If Y(n) is smaller than Ymin and larger than Ymax, then Y(n) is outside the error range 515. (Event 6) If Y(n) is smaller than Ymin and smaller than Ymax, then Y(n) is within the error range 515. (Event 7) If Y(n) is greater than Ymin and greater than Ymax, then Y(n) is within the error range 515. (Event 8) An event in which Y(n) is greater than Ymin and less than Ymax does not occur.

[0089] FIG. 12C is a graph showing an example in which the lower side of the error range 515 crosses the boundary of the angle. If the difference obtained by subtracting the error angle from the rotor angle (sensible angle): Y(0) of measurement point 300c, where it is determined that rotor 60 is in a stopped state, is a negative value, the value obtained by adding 360 to this difference, i.e., a value slightly smaller than 360 (deg), indicates the minimum angle Ymin of error range 515. In this case, as shown in the figure, the relationship of maximum angle Ymax of error range 515<minimum angle Ymin of error range 515 holds. In this case, the above-mentioned (Events 5) to (Event 8) also hold.

[0090] By summarizing these events, the origin determination process will be carried out in the following manner.

[0091] First step: The maximum angle Ymax and the minimum angle Ymin of the error range 515 are calculated based on the rotor angle (sensed angle): Y(0) of the measurement point 300 where it is determined that the rotor 60 is in a stopped state and the error angle.

[0092] Specifically, if the sum of the rotor angle (sensible angle): Y(0) of measurement point 300 where rotor 60 is determined to be in a stopped state and the error angle does not exceed 360 (deg), the sum is set as the maximum angle Ymax of error range 515. On the other hand, if the sum of Y(0) and the error angle exceeds 360 (deg), the value obtained by subtracting 360 (deg) from the sum is set as the maximum angle Ymax of error range 515 (see FIG. 12(B)).

[0093] Furthermore, if the difference obtained by subtracting the error angle from the rotor angle (sensible angle): Y(0) of measurement point 300 where rotor 60 is determined to be in a stopped state is not a negative value, the difference is set as the minimum angle Ymin of error range 515. On the other hand, if the difference obtained by subtracting the error angle from Y(0) is a negative value, the difference is added with 360 (deg) and set as the minimum angle Ymin of error range 515 (see FIG. 12(C)).

[0094] Second step: Determine whether the maximum angle Ymax of the error range 515 is larger than the minimum angle Ymin of the error range 515. Specifically, determine whether the following determination formula A is true or false. Judgment formula A: Judgment result A=Ymax>Ymin

[0095] Third step: The rotor angles (sensible angles) of the traced measurement points 301 to 305 are compared to determine whether they are larger or smaller than the minimum angle Ymin of the error range 515. Specifically, the following determination formula B is determined to be true or false. Judgment formula B: Judgment result B=Ymin <Y(n)

[0096] Fourth step: Determine the magnitude relationship between Y(n), the rotor angle (sensed angle) of the traced measurement points 301 to 305, and the maximum angle Ymax of the error range 515. Specifically, determine whether the following determination formula C is true or false. Judgment formula C: Judgment result C=Y(n) <Ymax

[0097] Fifth step: Using the results of the second to fourth steps, determine whether the following formula Z is true or false. Judgment formula Z: Judgment result Z = Judgment result A xor Judgment result B xor Judgment result C

[0098] FIG. 13 is a truth table for determining whether the error is within or outside the error range. Judgment formula Z can be judged based on the judgment results of judgment formula A, judgment formula B, and judgment formula C. If the judgment result Z of judgment formula Z is true (1), it can be determined that the rotor angle (sensible angle): Y(n) of the traced measurement points 301 to 305 is within the error range 515, and if the judgment result Z of judgment formula Z is false (0), it can be determined that Y(n) is outside the error range 515.

[0099] FIG. 14 is a functional block diagram of the motor-operated valve control device 200. Each component of the motor-operated valve control device 200 is realized by hardware (control circuit) including a control circuit (microcomputer) on a circuit board 118, storage devices such as memory and storage, and wired or wireless communication lines connecting them, and software stored in the storage device that supplies processing instructions to the arithmetic unit. The computer program may be composed of device drivers and application programs, as well as libraries that provide common functions to these programs. Each block described below represents a functional block, rather than a hardware configuration.

[0100] The motor-operated valve control device 200 includes a data processing unit 202 , a communication unit 204 , a reference information storage unit 206 , a recorded data storage unit 230 , 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 non-volatile memory. The recorded data storage unit 230 can store the rotor angle (sensed angle), step, and excitation pattern at each of the measurement points 301 to 315 as recorded data. The recorded data storage unit 230 may be a storage area configured in volatile memory or a storage area configured in non-volatile memory. The number of measurement point records to be retained is arbitrary, but may be, for example, a number equal to 2 n (e.g., 8, 16, or 32), including the record of the most recent step, and data for older steps is discarded. In other words, the area for storing the records of the rotor angle (sensed angle) may be a ring buffer. The number of records may be determined depending on the characteristics of the stepping motor's drive method (half-step, 1 / 4 microstep, 1 / 8 microstep, etc.). The data processing unit 202 performs various processes based on the reference information and various data acquired from the communication unit 204 and rotor interface unit 208. The data processing unit 202 also functions as an interface for the communication unit 204, rotor interface unit 208, reference information storage unit 206, and recorded data storage unit 230.

[0101] 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.

[0102] Rotor interface unit 208 includes a rotation instruction unit 214 and a rotation detection unit 216. Rotation instruction unit 214 outputs drive currents to U-phase coil 73a, V-phase coil 73b, and W-phase coil 73c in accordance with the excitation pattern. Rotation detection unit 216 reads the duty ratio (angle value) from the current pulses received from magnetic sensor 119.

[0103] The data processing unit 202 includes a rotation control unit 218, a stop detection unit 220, and an origin determination unit 222. The rotation control unit 218 controls the rotation instruction unit 214 to execute rotor rotation for origin detection. The stop detection unit 220 detects the stopped state of the rotor 60. The origin determination unit 222 determines the origin from among steps corresponding to measurement points based on the recorded data.

[0104] FIG. 15 is a flowchart showing the main processing steps. The rotation instruction unit 214 rotates the rotor 60 upward by several steps, for example, approximately N steps, under the control of the rotation control unit 218 (hereinafter referred to as "confirmation ascent") (S10). Thereafter, the rotation instruction unit 214 rotates the rotor 60 downward under the control of the rotation control unit 218. The confirmation ascent allows the rotor position and the excitation position to be aligned, thereby synchronizing the stepping motor. Furthermore, when the rotor 60 starts to rotate, there is a possibility that foreign matter such as metal chips may be caught in the screw feed mechanism 109 between the guide member 36 and the rotor 60. The reverse rotation of the rotor 60 accompanying the confirmation ascent can release the foreign matter caught in the rotor 60. In addition, the confirmation ascent applies appropriate vibration to the screw feed mechanism 109, which can encourage the foreign matter to fall out of the screw feed mechanism 109.

[0105] The rotation control unit 218 controls the rotation instructing unit 214 to rotate the rotor 60 downward at a predetermined rotation speed. The rotation instructing unit 214 rotates the rotor 60 downward one step at a time at predetermined intervals under the control of the rotation control unit 218 (S12). In other words, the rotation instructing unit 214 instructs the stepping motor to specify an angle so as to move the rotor 60 one step at a time in a direction in which the axial movement of the valve disc 34 is limited by the stop mechanism (in this example, the downward direction in which the stopper 90 abuts against the guide member 36).

[0106] The rotation detection unit 216 acquires the rotor angle (sensed angle) for each step based on the duty ratio (angle value) read from the pulse of the current received from the magnetic sensor 119 (S14).

[0107] The rotation control unit 218 adds the rotor angle (sensed angle), step, and excitation pattern to the recorded data for each step, and stores the data in the recorded data storage unit 230 (S16).

[0108] 9 and 10(A), the stop detection unit 220 detects the rotor's stopped state when the difference between the actual rotor angle (sensed angle) and the ideal rotor angle (command angle) exceeds a reference value (the deviation width of the rotor angle that can be estimated as being in tune) (Y in S18). If the difference between the actual rotor angle (sensed angle) and the ideal rotor angle (command angle) is equal to or less than the reference value, the stop state of the rotor 60 is not detected (N in S18).

[0109] If a stopped state of the rotor 60 is not detected (N in S18), the process returns to S12 and repeats the above-described process. If a stopped state of the rotor 60 is detected (Y in S18), the origin determination unit 222 performs an origin determination process (S20). As described with reference to FIG. 11(B), the origin determination unit 222 traces back one step in the recorded data from the step where the stopped state was detected, and determines whether the difference between the sensed angle at the step where the stopped state was detected and the sensed angle at the previous step is greater than a predetermined value (in this example, an error angle). The origin determination unit 222 then identifies the nearest step where the difference is greater than the predetermined value, and determines the next step in the forward direction from the identified nearest step as the origin of rotation of the rotor 60. Note that a value greater than the error angle may be used as the predetermined value to determine the next step in the forward direction from the nearest step as the origin of rotation of the rotor 60.

[0110] More specifically, according to the above-described first to fifth steps and the truth table (FIG. 13), origin determination unit 222 determines whether each of the traced back measurement points is inside or outside error range 515. For measurement points 305 that are outside error range 515, it is determined that the difference between the sensed angle at the step where the stopped state was detected and the sensed angle at the traced back step is larger than a predetermined value (in this example, the error angle).

[0111] That is, origin determination unit 222 sets error range 515, with the maximum angle being the angle obtained by rotation in the positive direction by a predetermined value (in this example, the error angle) from the sensed angle in the step in which the stopped state was detected, and the minimum angle being the angle obtained by rotation in the negative direction by a predetermined value from the sensed angle in the step in which the stopped state was detected. Then, if the sensed angle in the preceding step falls outside error range 515, origin determination unit 222 determines that the difference in the sensed angles is greater than the predetermined value. Furthermore, when a parameter (in this example, "degrees") that circulates at a predetermined interval (in this example, 360) is used as the angle of rotor 60, origin determination unit 222 performs the above-mentioned logical operation in the process of determining whether the angle is inside or outside error range 515. According to this logical operation, when error range 515 (an example of a reference range) includes the boundary of the parameter and the maximum angle indicates a value smaller than the minimum angle (see FIGS. 12B and 12C), origin determination unit 222 determines the range from the minimum angle of error range 515 to the upper limit of the predetermined width (360 (deg) in this example) and the range from the lower limit of the predetermined width (0 (deg) in this example) to the maximum angle of error range 515 as error range 515. Note that this concept can also be applied when the duty ratio is used as a parameter representing the angle of rotor 60.

[0112] Then, the origin determination unit 222 stores the excitation pattern of the measurement point determined to be the origin as origin information (reference information) in the reference information storage unit 206 (S22). The origin determination unit 222 may add the rotor angle (sensing angle) and / or duty ratio (angle value) corresponding to the excitation pattern to the origin information (reference information).

[0113] As shown in Figures 12(B) and 12(C), it is also possible to adjust the orientation or position of mechanical parts during the assembly process of the motor-operated valve 1 so as to prevent error range 515 from straddling the boundary of the angle range (0 (deg) and 360 (deg)). However, adjusting the orientation or position of mechanical parts during the assembly process is a cumbersome task. According to this embodiment, the orientation or position of mechanical parts can be handled by calculation processing within the motor-operated valve 1 without having to adjust it, thereby reducing the load of the assembly work.

[0114] [Variation 1] In this embodiment, an example has been shown in which the origin, i.e., the stop position of the stop mechanism that limits the axial motion of the valve disc 34, is determined. However, it is also possible to determine the position that triggers a step-out (hereinafter referred to as the "step-out trigger position") for step-out caused by factors other than the origin. In this case, instead of the stop detection unit 220, the motor-operated valve control device 200 is provided with a step-out detection unit (not shown) that detects a step-out state of the rotor 60 due to a restriction on axial motion (e.g., pinched metal chips) based on the measured rotor angle (sensed angle) for each step. The processing content of the step-out detection unit is equivalent to the processing of the stop detection unit 220 described in this embodiment. Furthermore, instead of the origin determination unit 222, the motor-operated valve control device 200 is provided with a trigger position determination unit (not shown). The trigger position determination unit traces the recorded data back one step at a time from the step in which the step-out state was detected and determines whether the difference between the sensed angle at the step in which the step-out state was detected and the sensed angle at the step back is greater than a predetermined value (in this example, an error angle). The trigger position determination unit then identifies the nearest step where the difference is greater than a predetermined value, and determines the next step in the direction of travel from the identified nearest step as the step-out trigger position. In other words, the measurement point (step) determined as the origin in this embodiment is determined as the step-out trigger position in Modification 1. In Modification 1, the cause of step-out is not necessarily the stop mechanism.

[0115] [Variation 2] In this embodiment, the origin is the position where the stop mechanism stops the valve disc 34, limiting its axial movement in the valve closing direction, i.e., the position where the lower stopper 90 abuts the guide member 36. However, the origin may also be the position where the stop mechanism stops the valve disc 34, limiting its axial movement in the valve opening direction. In this case, the rotation control unit 218 controls the rotation instruction unit 214 to rotate the valve disc 34 upward. The stop detection unit 220 detects a stopped state when the rotor angle (sensed angle) falls below the synchronization lower limit line 506. The origin determination unit 222 finds a measurement point in the previous step where the rotor angle (sensed angle) is outside the error range 515 and determines the next measurement point in the forward direction (upward direction) to be the origin.

[0116] [Variation 3] The motor-operated valve control device shown in this embodiment traces back the step progression order from the record of measurement point 300 to find measurement point 305 that indicates a rotor angle (sensed angle) that does not fall within error range 515. However, as a modified example, the motor-operated valve control device may also trace back the step progression order from the record of measurement points during rotation (e.g., measurement point 315) to find measurement point 304 that indicates a rotor angle (sensed angle) that falls within error range 515. The motor-operated valve control device determines that the measurement point 304 found first in the step progression order corresponds to the step where rotor 60 actually stopped. This step is then determined to be the origin for stopping by the stop mechanism. In other words, the origin determination unit 222 may identify a step to be determined according to the step progression order in the recorded data, determine whether the difference between the sensed angle at the step where a stopped state was detected and the sensed angle at the step to be determined is equal to or less than a predetermined value, and determine the step to be determined first to have the difference equal to or less than the predetermined value as the origin of rotor rotation. Alternatively, the trigger position determination unit in the first modification may determine that the step to be determined for which the difference is first determined to be equal to or smaller than the predetermined value as the step-out trigger position.

[0117] [Variation 4] In the present embodiment, the origin determination unit 222 determines whether the difference between the sensed angle at the step where the stopped state was detected and the sensed angle at the step back is greater than a predetermined value by going back one step at a time from the step where the stopped state was detected. However, as a modified example, the origin determination unit 222 may omit the determination at steps near the step where the stopped state was detected and go back from intermediate steps to make the determination. For example, the origin determination unit 222 may not make the determination up to the second step (measurement point 302 in FIG. 11B) immediately before the step where the stopped state was detected, but may make the determination by going back one step at a time from the third step (also measurement point 303). In other words, the origin determination unit 222 may repeatedly go back one step at a time from the middle of the step where the stopped state was detected (also measurement point 300) toward the origin. In the case of Modification 1, the trigger position determination unit may similarly go back one step at a time from the middle of the step where the stopped state was detected toward the step-out trigger position. The same applies to Modification 2.

[0118] [Variation 5] In the present embodiment, the most recent step in which the difference between the sensed angle at the step where the stopped state was detected and the sensed angle at the preceding step is greater than a predetermined value is identified, and the next step in the forward direction from the identified most recent step is determined as the origin of rotor rotation. However, the step identified by the origin discriminator 222 as having a sensed angle difference greater than the predetermined value is not limited to the most recent step. For example, the origin discriminator 222 may detect two consecutive steps in which the sensed angle difference is greater than the predetermined value and determine the next step in the forward direction from the second step as the origin. In other words, the origin discriminator 222 may identify a step in which the sensed angle difference is greater than the predetermined value and determine the step a predetermined number of steps in the forward direction from the identified step as the origin. In the case of the first modification, the trigger position discriminator may similarly identify a step in which the sensed angle difference is greater than the predetermined value and determine the step a predetermined number of steps in the forward direction from the identified step as the out-of-step trigger position. The same applies to the second modification.

[0119] [Variation 6] In the present embodiment, an example has been shown in which the stop position (origin) of the stop mechanism that limits the axial movement of the valve element 34 in the valve closing direction is used as the reference position in controlling the motor-operated valve 1, but the reference position is not limited to the origin. For example, the origin may be offset, and a position that is shifted a predetermined number of steps in the valve opening direction from the stop position (origin) may be defined as the reference position.

[0120] [Variation 7] In this embodiment, an example has been described in which information about the origin (reference point) detected at the manufacturing stage is recorded in the reference information storage unit 206, and the information is used at the operation stage, such as after the motor-operated valve 1 is mounted on the vehicle. As a method other than this embodiment, instead of detecting and recording the origin (reference point) at the manufacturing stage, the origin determination unit 222 may detect the origin (reference point) in a manner similar to this embodiment each time use of the motor-operated valve 1 is started (for example, each time power is supplied from the vehicle) at the operation stage.

[0121] [Other variations] Although a three-phase stepping motor is used as an example, a stepping motor other than a three-phase motor may be used, for example, a two-phase stepping motor may be used.

[0122] 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 also be magnetized. The number of poles can be set as appropriate, for example, to two poles on the valve body.

[0123] 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 this case, the area (outer diameter) of the sensor magnet may be increased so that the magnetic sensor can reliably detect magnetic flux. Because the sensor magnet protrudes beyond the outer periphery of the rotor core, the sensor magnet and rotor magnet can be easily injection molded.

[0124] In each embodiment, a laminated core (laminated magnetic core) has been exemplified as the core of the stator. In a modified example, a dust core or other core may be used. A dust core, also known as a "powder magnetic core," 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 the mixture.

[0125] In each embodiment, a configuration in which the drive circuit, control circuit, communication circuit, and power supply circuit are mounted on the underside of a 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. Alternatively, each circuit may be mounted on the top side of the circuit board. Part or all of the motor-operated valve control device 200 may be installed outside the motor-operated valve.

[0126] In each embodiment, a PM stepping motor is used as the motor unit, but a hybrid stepping motor may also be used. Furthermore, in the above embodiments, the motor unit is a three-phase motor, but other motors such as two-phase, four-phase, or five-phase motors may also be used. The number of electromagnetic coils in the stator is not limited to three or six, and may be set appropriately according to the number of phases of the motor.

[0127] The motor-operated valve of each embodiment is preferably applied to a refrigeration cycle that uses a refrigerant such as a chlorofluorocarbon alternative (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 provided in place of the condenser in the refrigeration cycle.

[0128] In each embodiment, the motor-operated valve is configured as an expansion valve, but it may also be configured as an on-off valve or a flow control valve that does not have an expansion function.

[0129] 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 just for vehicles. The motor-operated valve can also be configured to control the flow of fluids other than refrigerant.

[0130] The present embodiment is not limited to electric vehicles, but can be applied to various types of vehicles.

[0131] The sensor magnet 106 may be magnetized with four poles on both sides (two poles on both sides of the single-sided valve body). The magnetic flux can be strengthened by reversing the polarity of the magnetic poles on the top and bottom surfaces. 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.

[0132] The present invention is not limited to the above-described embodiments and modifications, and the components can be modified without departing from the spirit of the invention. Various inventions can be formed by appropriately combining multiple components disclosed in the above-described embodiments and modifications. Furthermore, some components can be omitted from all the components shown in the above-described embodiments and modifications. [Explanation of symbols]

[0133] 1 motor-operated valve, 2 valve body, 3 motor unit, 5 body, 6 first body, 8 second body, 10 male thread, 12 seal accommodating portion, 14 seal ring, 16 concave fitting portion, 18 seal accommodating portion, 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 engaging 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, 220 stop detection section, 222 origin determination section, 230 recorded data storage section

Claims

1. An electric valve control device for controlling an electric valve having a stepping motor that rotates a rotor, a first mechanism that converts the rotational motion of the rotor into axial motion of a valve body, a second mechanism that restricts the axial motion of the valve body, and a sensor that measures the angle of the rotor to obtain a sensed angle, a rotation instruction unit that instructs the stepping motor to specify an instruction angle so that the axial motion proceeds step by step in the direction restricted by the second mechanism; a rotation detection unit that acquires the sensed angle of the rotor from the sensor for each step; a storage unit that stores the sensed angle acquired for each step as recorded data; a stop detection unit that detects a stop state of the rotor due to restriction of the axial motion based on the acquired sensed angle for each step; an origin determination unit that repeatedly traces back steps in the recorded data, starting from the step where the stopped state was detected, determines whether the difference between the sensed angle at the step where the stopped state was detected and the sensed angle at the traced back step is greater than a predetermined value, identifies a step where the difference is greater than the predetermined value, and determines a step a predetermined number of steps forward from the identified step in the direction of advance as the origin of rotation of the rotor.

2. A parameter that circulates at a predetermined interval is used as the angle of the rotor, the origin determination unit sets a reference range in which the angle obtained by rotating the sensed angle in the step in which the stopped state was detected by the predetermined value in a positive direction is a maximum angle, and the angle obtained by rotating the sensed angle in the step in which the stopped state was detected by the predetermined value in a negative direction is a minimum angle, and when the sensed angle in the preceding step deviates from the reference range, it determines that the difference is greater than the predetermined value; 2. The electric valve control device according to claim 1, wherein, when the reference range includes the boundary of the parameter and the maximum angle indicates a value smaller than the minimum angle, a logical operation is performed to determine that the range from the minimum angle of the reference range to the upper limit of the specified width and the range from the lower limit of the specified width to the maximum angle of the reference range are the reference range.

3. An electric valve control device for controlling an electric valve having a stepping motor that rotates a rotor, a mechanism that converts the rotational motion of the rotor into axial motion of a valve body, and a sensor that measures the angle of the rotor to obtain a sensed angle, a rotation instruction unit that instructs the stepping motor to an instruction angle so as to advance one step at a time; a rotation detection unit that acquires the sensed angle of the rotor from the sensor for each step; a storage unit that stores the sensed angle acquired for each step as recorded data; a step-out detection unit that detects a step-out state of the rotor due to a restriction on the axial motion based on the sensed angle acquired for each step; an electric valve control device characterized by comprising a trigger position determination unit that repeatedly traces back steps in the recorded data, starting from the step where the out-of-step state was detected, determines whether the difference between the sensed angle at the step where the out-of-step state was detected and the sensed angle at the traced back step is greater than a predetermined value, identifies a step where the difference is greater than the predetermined value, and determines the step a predetermined number of steps forward from the identified step in the direction of progression as the trigger position for the out-of-step state.

4. a computer that controls an electrically operated valve having a stepping motor that rotates a rotor, a first mechanism that converts the rotational motion of the rotor into axial motion of a valve body, a second mechanism that limits the axial motion of the valve body, and a sensor that measures the angle of the rotor to obtain a sensed angle; a function of instructing the stepping motor to set an instruction angle so that the axial motion proceeds step by step in a direction restricted by the second mechanism; a function of acquiring the sensed angle of the rotor from the sensor for each step; a function of storing the acquired sensing angle as recorded data for each step; a function of detecting a stop state of the rotor due to restriction of the axial motion based on the acquired sensed angle for each step; a step in which the rotor is rotated a predetermined number of times in a forward direction from the step in which the stopped state was detected, ...

5. a computer that controls an electrically operated valve having a stepping motor that rotates a rotor, a mechanism that converts the rotational motion of the rotor into axial motion of a valve body, and a sensor that measures the angle of the rotor to obtain a sensed angle; a function of instructing the stepping motor to specify an angle so as to advance the step one by one; a function of acquiring the sensed angle of the rotor from the sensor for each step; a function of storing the acquired sensing angle as recorded data for each step; a function of detecting a step-out state of the rotor due to a restriction on the axial motion based on the sensed angle acquired for each step; An electric valve control program characterized by having the following function: in the recorded data, repeatedly going back through steps starting from the step where the out-of-step state was detected, determining whether the difference between the sensed angle at the step where the out-of-step state was detected and the sensed angle at the step going back is greater than a predetermined value, identifying a step where the difference is greater than the predetermined value, and determining that the step a predetermined number of steps forward from the identified step in the direction of advance is the position where the out-of-step occurred.

6. An electric valve control device for controlling an electric valve having a stepping motor that rotates a rotor, a first mechanism that converts the rotational motion of the rotor into axial motion of a valve body, a second mechanism that restricts the axial motion of the valve body, and a sensor that measures the angle of the rotor to obtain a sensed angle, a rotation instruction unit that instructs the stepping motor to specify an instruction angle so that the axial motion proceeds step by step in the direction restricted by the second mechanism; a rotation detection unit that acquires the sensed angle of the rotor from the sensor for each step; a storage unit that stores the sensed angle acquired for each step as recorded data; a stop detection unit that detects a stop state of the rotor due to restriction of the axial motion based on the acquired sensed angle for each step; an origin determination unit that identifies a step to be determined in the recorded data according to the order in which the steps progress, determines whether a difference between the sensed angle at the step in which the stopped state was detected and the sensed angle at the step to be determined is equal to or less than a predetermined value, and determines the step to be determined for which the difference is first determined to be equal to or less than the predetermined value as the origin of rotation of the rotor.

7. An electric valve control device for controlling an electric valve having a stepping motor that rotates a rotor, a mechanism that converts the rotational motion of the rotor into axial motion of a valve body, and a sensor that measures the angle of the rotor to obtain a sensed angle, a rotation instruction unit that instructs the stepping motor to an instruction angle so as to advance one step at a time; a rotation detection unit that acquires the sensed angle of the rotor from the sensor for each step; a storage unit that stores the sensed angle acquired for each step as recorded data; a step-out detection unit that detects a step-out state of the rotor due to a restriction on the axial motion based on the sensed angle acquired for each step; an electric valve control device characterized by comprising: a trigger position determination unit that identifies a step to be determined in the recorded data according to the order in which the steps progress, determines whether the difference between the sensed angle at the step in which the out-of-step state was detected and the sensed angle at the step to be determined is less than or equal to a predetermined value, and determines the step to be determined that the difference is first less than or equal to the predetermined value as the trigger position of the out-of-step.

8. a computer that controls an electrically operated valve having a stepping motor that rotates a rotor, a first mechanism that converts the rotational motion of the rotor into axial motion of a valve body, a second mechanism that limits the axial motion of the valve body, and a sensor that measures the angle of the rotor to obtain a sensed angle; a function of instructing the stepping motor to set an instruction angle so that the axial motion proceeds step by step in a direction restricted by the second mechanism; a function of acquiring the sensed angle of the rotor from the sensor for each step; a function of storing the acquired sensing angle as recorded data for each step; a function of detecting a stop state of the rotor due to restriction of the axial motion based on the acquired sensed angle for each step; a step to be judged in accordance with the order in which the steps are progressed in the recorded data; a step to be judged in accordance with the order in which the steps are progressed; a step to be judged in accordance with the order in which the steps are progressed; a step to be judged in accordance with the order in which the steps are progressed; a step to be judged in accordance with the order in which the steps are progressed; a step to be judged in accordance with the order in which the steps are progressed; a step to be judged in accordance with the order in which the steps are progressed;

9. a computer that controls an electrically operated valve having a stepping motor that rotates a rotor, a mechanism that converts the rotational motion of the rotor into axial motion of a valve body, and a sensor that measures the angle of the rotor to obtain a sensed angle; a function of instructing the stepping motor to specify an angle so as to advance the step one by one; a function of acquiring the sensed angle of the rotor from the sensor for each step; a function of storing the acquired sensing angle as recorded data for each step; a function of detecting a step-out state of the rotor due to a restriction on the axial motion based on the sensed angle acquired for each step; an electric valve control program that performs the function of identifying a step to be judged in the recorded data according to the order in which the steps progress, determining whether the difference between the sensed angle at the step where the out-of-step state was detected and the sensed angle at the step to be judged is less than or equal to a predetermined value, and determining that the step to be judged for which the difference is first judged to be less than or equal to the predetermined value is the trigger position for the out-of-step state.

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