Electric valve control device and electric valve device

Abstract

To provide a motor-driven valve control device and a motor-driven valve device capable of suppressing an increase in an internal temperature of a motor driver.SOLUTION: Upon receipt of a valve opening degree changing command including a target valve opening degree Dt of a motor-driven valve 5, a computer 80 of a motor-driven valve control device 70 acquires a target number Nt, which is the number of pulses P to be input to a motor driver 77, to bring the valve opening degree of the motor-driven valve 5 to the target valve opening degree Dt. Upon determination that an ambient temperature Ta of the motor driver 77 is not high, the computer 80 continuously inputs the pulse P of the target number Nt to the motor driver 77. Upon determination that the ambient temperature Ta is high, the computer 80 continuously inputs the pulse P by unit number Nu to the motor driver 77 until the number of pulses P input to the motor driver 77 reaches the target number Nt while providing a pulse input pause period each time the pulse P of the unit number Nu is input.SELECTED DRAWING: Figure 9

Description

Technical Field

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

Background Art

[0002] Patent Document 1 discloses an example of a conventional electric valve device. The electric valve device includes an electric valve and an electric valve control device. The electric valve is incorporated into the refrigeration cycle of an air conditioner. The electric valve includes a valve body, a valve element, and a stepping motor for moving the valve element. The stepping motor includes a rotor and a stator. The stepping motor is connected to a motor driver of the electric valve control device. When a pulse is input to the motor driver, the motor driver supplies a drive current corresponding to the pulse to the stator to rotate the rotor. In response to the rotation of the rotor, the valve element moves, and the valve opening degree of the electric valve is changed.

[0003] The electric valve is controlled by the electric valve control device. The electric valve control device changes the valve opening degree of the electric valve within the range from the minimum opening degree to the maximum opening degree. When the electric valve control device receives a valve opening degree change command including the target valve opening degree of the electric valve from the air conditioner control device, it inputs the number of pulses calculated based on the target valve opening degree to the motor driver. Thereby, the valve opening degree of the electric valve is changed to the target valve opening degree.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The motor driver has a die on which an integrated circuit is formed and an IC package in which the die is encapsulated. Based on the junction temperature of the motor driver and the like, the range of the ambient temperature (operating temperature range) when the motor driver is in use is defined. The electric valve device may be installed in a high-temperature location such as an engine room of a vehicle. When the motor driver is used in a high-temperature environment, the internal temperature of the motor driver tends to rise. The rise in the internal temperature of the motor driver can cause malfunction or failure.

[0006] Therefore, an object of the present invention is to provide an electric valve control device capable of suppressing the rise in the internal temperature of a motor driver and an electric valve device having the electric valve control device.

Means for Solving the Problems

[0007] In order to achieve the above object, an electric valve control device according to an aspect of the present invention is an electric valve control device that controls an electric valve having a stepping motor, and has a control unit that inputs a pulse to a motor driver connected to the stepping motor, the motor driver supplies a drive current corresponding to the pulse to the stepping motor, when the control unit receives a valve opening degree change command including a target valve opening degree of the electric valve, the control unit obtains a target number that is the number of pulses input to the motor driver to make the valve opening degree of the electric valve the target valve opening degree, when the control unit determines that the ambient temperature of the motor driver is not high, the control unit continuously inputs the target number of pulses to the motor driver, when the control unit determines that the ambient temperature is high, the control unit obtains a unit number that is the number of pulses continuously input to the motor driver, and continuously inputs pulses to the motor driver by the unit number until the number of pulses input to the motor driver reaches the target number, and a pulse input pause period is provided every time the unit number of pulses is input.

[0008] In the present invention, the stepping motor has an A-phase stator and a B-phase stator, the motor driver supplies drive currents corresponding to pulses to the A-phase stator and the B-phase stator, and it is preferable that the pulse input to the motor driver immediately before the pulse input pause period is a pulse that causes the motor driver to supply a drive current to only the A-phase stator or only the B-phase stator.

[0009] In the present invention, it is preferable that the length of the pulse input pause period is equal to or longer than the length of time required for the input of the unit number of pulses immediately before the pulse input pause period.

[0010] To achieve the above object, an electric valve device according to another aspect of the present invention includes an electric valve having a stepping motor and the electric valve control device.

Effect of the Invention

[0011] When the electric valve control device determines that the ambient temperature of the motor driver is not high, it continuously inputs a target number of pulses to the motor driver at once. When the electric valve control device determines that the ambient temperature of the motor driver is high, it does not input a target number of pulses to the motor driver at once, but inputs pulses to the motor driver one unit number at a time. Then, the electric valve control device provides a pulse input pause period during which no pulse is input every time it inputs a unit number of pulses to the motor driver. Therefore, it is possible to avoid continuous operation of the motor driver for a long time and suppress an increase in the internal temperature of the motor driver.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Embodiment for Carrying Out the Invention

[0013] Hereinafter, the configuration of the electric valve device according to an embodiment of the present invention will be described with reference to FIGS. 1 to 5. The electric valve device 1 according to this embodiment is used, for example, as a flow control valve for controlling the refrigerant flow rate in the refrigeration cycle of an air conditioner.

[0014] FIG. 1 is a block diagram of an air conditioner system having an electric valve device according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of the electric valve device of FIG. 1. In FIG. 2, a stator and an electric valve control device are schematically shown. In FIG. 2, illustration of a housing that houses the stator and the electric valve control device is omitted. FIG. 3 is a plan view of a valve shaft holder, a stopper member, a rotor, and a stator included in the electric valve device of FIG. 1. In FIG. 3, the stator is schematically shown. In FIG. 3, magnetic poles of the rotor are schematically shown. FIG. 4 is a diagram for explaining a computer, a motor driver, and a stepping motor included in the electric valve device of FIG. 1. FIG. 4A schematically shows connections between the computer, the motor driver, and the stepping motor. FIG. 4B shows an example of correspondence between a pulse and a drive current supplied by the motor driver to the stator. FIG. 5 is a diagram showing an example of a data table indicating correspondence between the number of pulses input to the motor driver and the valve opening degree of the electric valve.

[0015] FIG. 1 shows an example of an air conditioner system 100 mounted on a vehicle. This air conditioner system 100 has a compressor 101, a condenser 102, an electric valve device 1 (electric valve 5), and an evaporator 103 that are connected in sequence via a pipe 105. The electric valve device 1 is an expansion valve. The air conditioner system 100 has an air conditioner control device 110. The air conditioner control device 110 is communicably connected to the electric valve device 1. The air conditioner control device 110 controls the flow rate of the refrigerant flowing through the pipe 105 using the electric valve device 1.

[0016] As shown in FIG. 2, the electric valve device 1 has an electric valve 5 and an electric valve control device 70.

[0017] The electric valve 5 has a valve body 10, a stem 20, a valve element 30, a drive mechanism 40, and a stator 60.

[0018] The valve body 10 has a main body member 11 and a connecting member 13. The main body member 11 has a cylindrical shape. The main body member 11 has a valve chamber 14. A first conduit 15 and a second conduit 16 are joined to the main body member 11. The first conduit 15 is arranged along a direction orthogonal to the axis L (the left - right direction in FIG. 2) and is connected to the valve chamber 14. The second conduit 16 is arranged along the axis L direction (the up - down direction in FIG. 2) and is connected to the valve chamber 14 via a valve port 17. The valve port 17 is surrounded by an annular valve seat 18 in the valve chamber 14. A circular fitting hole 11a is formed in the upper end surface of the main body member 11. The inner peripheral surface of the fitting hole 11a has a plane 11d facing leftward in FIG. 2. A through - hole 11b communicating with the valve chamber 14 is formed in the bottom surface of the fitting hole 11a. The connecting member 13 has an annular plate shape. The inner peripheral edge of the connecting member 13 is joined to the upper end portion of the main body member 11. The main body member 11 and the connecting member 13 are made of a metal such as an aluminum alloy, stainless steel, or brass.

[0019] The cam 20 is made of a metal such as stainless steel. The cam 20 has a cylindrical shape with an open lower end and a closed upper end. The lower end of the cam 20 is joined to the outer peripheral edge of the connecting member 13.

[0020] The valve element 30 has a first shaft portion 31, a second shaft portion 32, and a valve portion 33. The first shaft portion 31 and the second shaft portion 32 have a cylindrical shape. The diameter of the second shaft portion 32 is smaller than the diameter of the first shaft portion 31. The second shaft portion 32 is coaxially connected to the upper end portion of the first shaft portion 31. A stepped portion 34, which is an upward - facing annular plane, is formed at the connected portion of the first shaft portion 31 and the second shaft portion 32. The valve portion 33 has a substantially conical shape in which the diameter decreases from top to bottom. The valve portion 33 is coaxially connected to the lower end portion of the first shaft portion 31. The tip of the valve portion 33 is arranged at the valve port 17. A variable throttle portion is formed between the valve portion 33 and the valve port 17. The valve portion 33 is arranged facing the valve seat 18. The valve portion 33 contacts the valve seat 18 in the closed - valve state.

[0021] The drive mechanism 40 moves the valve body 30 in the vertical direction (the direction of the axis L). The opening degree of the valve port 17 (that is, the valve opening degree of the electric valve 5) changes with the movement of the valve body 30. The drive mechanism 40 includes a rotor 41, a valve shaft holder 42, a guide bush 43, a stopper member 44, and a fixture 45.

[0022] The rotor 41 has a cylindrical shape. The outer diameter of the rotor 41 is slightly smaller than the inner diameter of the cam 20. The rotor 41 is disposed inside the cam 20. The rotor 41 is rotatable relative to the valve body 10. A plurality of N poles and a plurality of S poles are formed on the outer peripheral surface of the rotor 41. The plurality of N poles and the plurality of S poles extend in the vertical direction. The plurality of N poles and the plurality of S poles are alternately arranged at equal angular intervals in the circumferential direction. In this embodiment, the rotor 41 has 12 N poles and 12 S poles. The angle between adjacent N poles and S poles is 15 degrees.

[0023] The valve shaft holder 42 has a cylindrical shape with an open lower end and a closed upper end. The valve shaft holder 42 is fitted into the fitting hole 41a of the rotor 41. The valve shaft holder 42 rotates together with the rotor 41. The valve shaft holder 42 has a movable stopper 42s. The movable stopper 42s is a protrusion that projects radially outward from the lower end of the outer peripheral surface of the valve shaft holder 42. A shaft hole 42b is formed in the upper wall portion 42a of the valve shaft holder 42. The second shaft portion 32 of the valve body 30 is disposed in the shaft hole 42b so as to be movable in the direction of the axis L. A washer 46 is disposed on the lower surface of the upper wall portion 42a of the valve shaft holder 42. A closing spring 47 is disposed between the washer 46 and the stepped portion 34 of the valve body 30. The closing spring 47 is a coil spring and presses the valve body 30 toward the valve seat 18. A female thread 42c is formed on the inner peripheral surface of the valve shaft holder 42. The movable stopper 42s is fixed to the rotor 41.

[0024] The guide bush 43 has a base portion 43a and a support portion 43b. The base portion 43a and the support portion 43b have a cylindrical shape. The outer peripheral surface of the base portion 43a has a flat surface 43d. The base portion 43a is press-fitted into the fitting hole 11a of the main body member 11, and the flat surface 43d contacts the flat surface 11d of the fitting hole 11a. Thereby, the central axis of the main body member 11 and the central axis of the guide bush 43 coincide on the axis L, and the guide bush 43 is correctly positioned around the axis L with respect to the main body member 11. The outer diameter of the support portion 43b is smaller than the outer diameter of the base portion 43a. The inner diameter of the support portion 43b is the same as the inner diameter of the base portion 43a. The support portion 43b is coaxially connected to the upper end portion of the base portion 43a. A male thread 43c is formed on the outer peripheral surface of the support portion 43b. The male thread 43c is screwed into the female thread 42c of the valve shaft holder 42. The valve shaft holder 42 and the guide bush 43 constitute a screw mechanism that converts the rotation of the rotor 41 into a linear motion. The first shaft portion 31 of the valve body 30 is disposed inside the guide bush 43. The guide bush 43 supports the valve body 30 so as to be movable in the direction of the axis L.

[0025] The stopper member 44 has a stopper body 44a. The stopper body 44a has a cylindrical shape. A female thread 44c is formed on the inner peripheral surface of the stopper body 44a. The stopper body 44a has a fixed stopper 44s. The fixed stopper 44s is a protrusion that projects radially outward from the outer peripheral surface of the stopper body 44a. The female thread 44c is screwed into the male thread 43c until the stopper body 44a contacts the base portion 43a of the guide bush 43. Thereby, the stopper member 44 is fixed to the guide bush 43. The fixed stopper 44s is fixed to the valve body 10.

[0026] The fixture 45 has a fixing portion 45a and a flange portion 45b. The fixing portion 45a has a stepped cylindrical shape. Inside the fixing portion 45a, the second shaft portion 32 of the valve body 30 is disposed. The fixing portion 45a is joined to the second shaft portion 32. The flange portion 45b is continuously provided at the lower end portion of the fixing portion 45a. A return spring 48 is disposed outside the fixture 45. The return spring 48 is a coil spring. Note that the return spring 48 is not an essential component in the present invention.

[0027] The stator 60 has a cylindrical shape. The stator 60 has a phase-A stator 61 and a phase-B stator 62.

[0028] The phase-A stator 61 has a plurality of claw-pole type pole teeth 61a, 61b on its inner circumference. The tip of the pole tooth 61a faces downward, and the tip of the pole tooth 61b faces upward. The pole teeth 61a and 61b are alternately arranged at equal angular intervals in the circumferential direction. In the present embodiment, the phase-A stator 61 has 12 pole teeth 61a and 12 pole teeth 61b. The angle between two adjacent pole teeth 61a and 61b is 15 degrees. When the coil 61c of the phase-A stator 61 is energized, the pole teeth 61a and 61b become magnetic poles with different polarities from each other.

[0029] The phase-B stator 62 has a plurality of claw-pole type pole teeth 62a, 62b on its inner circumference. The tip of the pole tooth 62a faces downward, and the tip of the pole tooth 62b faces upward. The pole teeth 62a and 62b are alternately arranged at equal angular intervals in the circumferential direction. In the present embodiment, the phase-B stator 62 has 12 pole teeth 62a and 12 pole teeth 62b. The angle between two adjacent pole teeth 62a and 62b is 15 degrees. When the coil 62c of the phase-B stator 62 is energized, the pole teeth 62a and 62b become magnetic poles with different polarities from each other.

[0030] The A-phase stator 61 and the B-phase stator 62 are coaxially arranged. The angle between the pole teeth 61a of the A-phase stator 61 and the pole teeth 62a of the B-phase stator 62, when viewed from the direction of the axis L, is 7.5 degrees. That is, the B-phase stator 62 is at a position rotated 7.5 degrees around the axis L with respect to the A-phase stator 61 from the position where the pole teeth 61a and the pole teeth 62a are aligned in the direction of the axis L. As shown in Fig. 4A, the terminals A1, A2 of the coil 61c of the A-phase stator 61 and the terminals B1, B2 of the coil 62c of the B-phase stator 62 are connected to the motor driver 77 of the motor valve control device 70.

[0031] Inside the stator 60, the can 20 is arranged. The stator 60, together with the rotor 41 arranged inside the can 20, constitutes a stepping motor 66.

[0032] When a pulse P is input to the stepping motor 66, the rotor 41 rotates. Specifically, the rotor 41 rotates when a drive current corresponding to the pulse P is supplied to the stator 60 of the stepping motor 66. In this specification, "when a pulse P is input to the stepping motor 66" is synonymous with "when a drive current corresponding to the pulse P is supplied to the stator 60 of the stepping motor 66".

[0033] Pulses P[1] to P[8] shown in Fig. 4B are input to the stepping motor 66 in order. In this embodiment, the speed of the pulse P is 125 pps. The speed of the pulse P may be 400 pps. The speed of the pulse P is appropriately set according to the system in which the motor valve device 1 is incorporated, etc.

[0034] When rotating the rotor 41 in one direction (clockwise in FIG. 3), pulses P are cyclically input to the stepping motor 66 in ascending order (in the order of pulses P[1] to P[8]). When the rotor 41 rotates in one direction, the rotor 41 moves downward due to the screw feed action between the female thread 42c of the valve shaft holder 42 and the male thread 43c of the guide bush 43. The rotor 41 pushes the valve body 30 downward via the valve closing spring 47. The valve body 30 moves downward and the valve portion 33 contacts the valve seat 18. The position of the rotor 41 at this time is the valve closing position Rc. When the rotor 41 is further rotated in one direction from this state, the valve closing spring 47 is compressed and the rotor 41 moves further downward. The valve body 30 does not move downward. Then, when the movable stopper 42s of the valve shaft holder 42 contacts the fixed stopper 44s of the stopper member 44, the rotation of the rotor 41 in one direction is restricted. The position of the rotor 41 at this time is the reference position Rx. The movable stopper 42s and the fixed stopper 44s are the stopper mechanism 49 that restricts the rotation of the rotor 41 in one direction.

[0035] When rotating the rotor 41 in the other direction opposite to the one direction (counterclockwise in FIG. 3), pulses P are cyclically input to the stepping motor 66 in descending order (in the order of pulses P[8] to P[1]). When the rotor 41 rotates in the other direction, the rotor 41 moves upward due to the screw feed action between the female thread 42c of the valve shaft holder 42 and the male thread 43c of the guide bush 43. The valve shaft holder 42 moves upward together with the rotor 41, and the valve shaft holder 42 pushes the fixture 45 upward. The valve body 30 moves upward together with the fixture 45, and the valve body 30 separates from the valve seat 18. The position of the rotor 41 when the flow rate of the fluid at the valve port 17 is a predetermined set value in a predetermined flow rate measurement environment is defined as the valve opening position Ro. The set value is appropriately set according to the configuration and application of the electric valve device 1.

[0036] When the rotor 41 rotates in one direction, the valve port 17 closes, and when the rotor 41 rotates in the other direction, the valve port 17 opens. That is, one direction is the valve closing direction and the other direction is the valve opening direction.

[0037] The opening degree of the valve port 17 corresponds to the valve opening degree of the electric valve 5. The electric valve 5 is controlled so that the valve opening degree is within the range from the minimum opening degree (0%) to the maximum opening degree (100%).

[0038] In this embodiment, when the rotor 41 is at a position (reference position Rx) where the rotation in one direction is restricted by the stopper mechanism 49, the valve opening degree is the minimum opening degree (0%) of the electric valve 5. Also, when the rotor 41 is at a position (fully open position Rz) where the valve port 17 has an opening degree that allows the refrigerant with a flow rate of 90% of the maximum flow rate (for example, Cv value) of the electric valve 5 to flow, the valve opening degree is the maximum opening degree (100%) of the electric valve 5. The number of pulses P required to rotate the rotor 41 from the reference position Rx to the fully open position Rz is 500.

[0039] Note that the settings of the minimum opening degree and the maximum opening degree are not limited to the above. For example, the valve opening degree when the valve leakage amount of the electric valve 5 reaches a predetermined flow rate when the rotor 41 rotates in the valve opening direction from the valve closed position Rc may be the minimum opening degree (0%) of the electric valve 5. Or, the valve opening degree when the rotor 41 is at the valve closed position Rc or the valve open position Ro may be the minimum opening degree (0%) of the electric valve 5. Also, the valve opening degree when the rotor 41 is at a position immediately before the screw engagement between the female screw 42c and the male screw 43c is disengaged may be the maximum opening degree (100%) of the electric valve 5.

[0040] The electric valve control device 70 has a substrate 71 on which a plurality of electronic components (not shown) are mounted. The substrate 71 and the stator 60 are housed in a housing (not shown) made of synthetic resin. As shown in FIG. 1, the electric valve control device 70 has a non-volatile memory 75, a communication device 76, a motor driver 77, and a computer 80. The electric valve control device 70 controls the electric valve 5 based on a command received from the air conditioner control device 110.

[0041] The non-volatile memory 75 stores data that needs to be retained even when the power is cut off. The non-volatile memory 75 is, for example, an EEPROM or a flash memory.

[0042] The communication device 76 is communicably connected to the air conditioner control device 110 via the wired communication bus 120. The air conditioner system 100 employs a communication method such as, for example, Local Interconnect Network (LIN) or Controller Area Network (CAN). Note that the communication device 76 may be wirelessly communicably connected to the air conditioner control device 110.

[0043] The motor driver 77 supplies a drive current to the stepping motor 66 based on the pulse P input from the computer 80. As shown in FIG. 4A, the motor driver 77 is connected to the terminals A1, A2 of the coil 61c of the A-phase stator 61 and the terminals B1, B2 of the coil 62c of the B-phase stator 62. FIG. 4B shows an example of the correspondence between the pulse P and the drive current supplied by the motor driver 77. In FIG. 4B, (+) indicates supplying a drive current from terminal A1 to terminal A2 or from terminal B1 to terminal B2, (-) indicates supplying a drive current from terminal A2 to terminal A1 or from terminal B2 to terminal B1, and (0) indicates not supplying a drive current.

[0044] When the pulse P[1] or P[5] is input to the motor driver 77, the motor driver 77 supplies a drive current only to the coil 61c of the A-phase stator 61. When a drive current is supplied only to the coil 61c, the pole teeth 61a, 61b of the A-phase stator 61 face the poles of the rotor 41 in the radial direction. When the supply of the drive current to the coil 61c is stopped in this state, the poles of the rotor 41 attract the pole teeth 61a, 61b of the A-phase stator 61, and the detent torque of the stepping motor 66 becomes relatively large.

[0045] When a pulse P[3] or P[7] is input to the motor driver 77, the motor driver 77 supplies a drive current only to the coil 62c of the B-phase stator 62. When a drive current is supplied only to the coil 62c, the pole teeth 62a and 62b of the B-phase stator 62 and the poles of the rotor 41 face each other in the radial direction. When the supply of the drive current to the coil 62c is stopped in this state, the poles of the rotor 41 attract the pole teeth 62a and 62b of the B-phase stator 62, and the detent torque of the stepping motor 66 becomes relatively large.

[0046] When the detent torque of the stepping motor 66 is large, it is possible to suppress the rotor 41 from rotating due to vibration or the like.

[0047] When a pulse P[2], P[4], P[6] or P[8] is input to the motor driver 77, the motor driver 77 supplies a drive current to the coil 61c of the A-phase stator 61 and the coil 62c of the B-phase stator 62. When the supply of the drive current to the coil 61c and the coil 62c is stopped in this state, the detent torque of the stepping motor 66 becomes relatively small.

[0048] The computer 80 is a microcomputer for embedded devices in which a CPU, a ROM, a RAM, an input / output interface (I / O), a timer, and a temperature sensor are incorporated in one package. The computer 80 is arranged near the motor driver 77 so that the temperature sensor can measure the ambient temperature Ta of the motor driver 77. The computer 80 may include a non-volatile memory 75, a communication device 76, and the motor driver 77. An external temperature sensor or an external analog-to-digital converter may be connected to the computer 80. The computer 80 is a control unit.

[0049] In the ROM of the computer 80, programs executed by the CPU and various setting values that do not need to be rewritten are stored.

[0050] In this embodiment, a data table G is stored in the ROM of the computer 80. The data table G shows the correspondence between the number of pulses input to the motor driver 77 and the valve opening degree of the motorized valve 5. Specifically, in the data table G, the number of pulses P (0 to 500) input to the motor driver 77 when the rotor 41 is at the reference position Rx, and the valve opening degree (0 to 100%) corresponding to the position where the rotor 41 is positioned by the input of the number of pulses P are associated with each other. FIG. 5 shows an example of the data table G. Note that the correspondence between the number of pulses input to the stepping motor 66 and the valve opening degree of the motorized valve 5 may be shown by a calculation formula.

[0051] A unit number Nu is stored in the ROM of the computer 80. The unit number Nu is the number of pulses P continuously input to the motor driver 77 when the ambient temperature Ta of the motor driver 77 is high. When the computer 80 determines that the ambient temperature Ta of the motor driver 77 is high, the computer 80 makes the number of pulses P continuously input to the motor driver 77 not exceed the unit number Nu. The unit number Nu is set to the number of pulses P (permissible number) that can be continuously input when the ambient temperature Ta of the motor driver 77 is high. In this embodiment, the unit number Nu is 24, and the unit number Nu is set in the range of 2 to 250.

[0052] The length E of the pulse input pause period is stored in the ROM of the computer 80. The pulse input pause period is a period during which the computer 80 does not input the pulse P to the motor driver 77. The pulse input pause period is provided after the unit number Nu of pulses P is input to the motor driver 77. In this embodiment, the length E of the pulse input pause period is 192 ms, and the length E is the same as the length of time required for the continuous input of the unit number Nu of pulses P. The length E is set in the range of 16 to 2000 ms. The length E is preferably not less than the time required for the input of the unit number Nu of pulses P immediately before the pulse input pause period.

[0053] The high-temperature determination threshold Th is stored in the ROM of the computer 80. The high-temperature determination threshold Th is used when determining whether the ambient temperature Ta of the motor driver 77 is high.

[0054] The data table G, the unit number Nu, the length E of the pulse input pause period, and the high-temperature determination threshold Th may be stored in the non-volatile memory 75.

[0055] The RAM of the computer 80 is a working memory used when the CPU executes a program. The current valve opening Dc indicating the current valve opening degree of the electric valve 5 is stored in the RAM of the computer 80. The current valve opening Dc is copied from the RAM to the non-volatile memory 75 when the power of the electric valve control device 70 is cut off or when shifting to the sleep mode. The current valve opening Dc is copied from the non-volatile memory 75 to the RAM when the power of the electric valve control device 70 is turned on or when resuming from the sleep mode. Also, the first counter C1 and the second counter C2 are stored in the RAM of the computer 80.

[0056] Next, an example of the process executed by the electric valve control device 70 will be described with reference to FIGS. 6 and 7. FIGS. 6 and 7 are flowcharts showing an example of the process executed by the computer 1 included in the electric valve device of FIG. 1 80 is a flowchart showing an example of the process executed.

[0057] When the power of the electric valve control device 70 (specifically, the computer 80) is turned on or when resuming from the sleep mode, it shifts to the operation mode. In the operation mode, the electric valve control device 70 waits for a command from the air conditioner control device 110. Then, when the electric valve control device 70 receives a valve opening degree change command from the air conditioner control device 110, it executes the process shown in the flowcharts of FIGS. 6 and 7. The valve opening degree change command includes the target value (target valve opening degree Dt) of the valve opening degree of the electric valve 5.

[0058] The electric valve control device 70 obtains a target number Nt, which is the number of pulses P input to the motor driver 77 to set the valve opening to the target valve opening Dt based on the target valve opening Dt included in the valve opening change command (S110). Specifically, the electric valve control device 70 obtains the target valve opening Dt from the valve opening change command and reads the current valve opening Dc from the RAM. The electric valve control device 70 refers to the data table G and obtains the difference value between the number of pulses associated with the target valve opening Dt and the number of pulses associated with the current valve opening Dc as the target number Nt.

[0059] The electric valve control device 70 determines whether the ambient temperature Ta of the motor driver 77 is high (S120). Specifically, the electric valve control device 70 obtains the ambient temperature Ta of the motor driver 77 based on the signal from the temperature sensor and compares the ambient temperature Ta with the high-temperature determination threshold Th.

[0060] When the ambient temperature Ta is less than the high-temperature determination threshold Th (N in S120), the electric valve control device 70 determines that the ambient temperature Ta is not high and executes normal processing (S130 to S160). When the ambient temperature Ta is greater than or equal to the high-temperature determination threshold Th (in S120 Y ), the electric valve control device 70 determines that the ambient temperature Ta is high and executes high-temperature processing (S210 to S300).

[0061] In normal processing, the electric valve control device 70 sets the first counter C1 to 0 (S130). The electric valve control device 70 determines whether the first counter C1 is equal to the target number Nt (S140). If the first counter C1 is not equal to the target number Nt (N in S140), the electric valve control device 70 inputs one pulse P to the motor driver 77 (S150). At this time, if the target valve opening Dt is smaller than the current valve opening Dc, the electric valve control device 70 inputs the pulse P in ascending order. The rotor 41 rotates in the valve closing direction. Or, if the target valve opening Dt is larger than the current valve opening Dc, the electric valve control device 70 inputs the pulse P in descending order. The rotor 41 rotates in the valve opening direction. The electric valve control device 70 increments the first counter C1 by 1 (S160) and returns to the determination of the first counter C1 (S140). Then, the electric valve control device 70 repeats the input of the pulse P until the first counter C1 reaches the target number Nt (S140 - S160). When the first counter C1 reaches the target number Nt (Y in S140), the electric valve control device 70 stores the target valve opening Dt as the current valve opening Dc in the RAM and ends the process.

[0062] In high-temperature processing, the electric valve control device 70 sets the first counter C1 to 0 and the second counter C2 to 0 (S210). The electric valve control device 70 reads the unit number Nu from the ROM. The electric valve control device 70 determines whether the first counter C1 is equal to the target number Nt and whether the second counter C2 is equal to the unit number Nu (S220, S230). If the first counter C1 is not equal to the target number Nt and the second counter C2 is not equal to the unit number Nu (N in S220, N in S230), the electric valve control device 70 inputs one pulse P to the motor driver 77 (S240). At this time, if the target valve opening Dt is smaller than the current valve opening Dc, the electric valve control device 70 inputs the pulse P in ascending order. The rotor 41 rotates in the valve closing direction. Or, if the target valve opening Dt is larger than the current valve opening Dc, the electric valve control device 70 inputs the pulse P in descending order. The rotor 41 rotates in the valve opening direction. The electric valve control device 70 increments the first counter C1 by 1 and increments the second counter C2 by 1 (S250) and returns to the determination of the first counter C1 (S220).

[0063] If the first counter C1 is not the target number Nt and the second counter C2 is the unit number Nu (N in S220, Y in S230), the electric valve control device 70 determines whether the last input pulse P to the motor driver 77 is any of P[1], P[3], P[5], and P[7] (S260).

[0064] If the last input pulse P to the motor driver 77 is not any of P[1], P[3], P[5], and P[7] (N in S260), the electric valve control device 70 inputs one pulse P to the motor driver 77 (S270). At this time, if the target valve opening Dt is smaller than the current valve opening Dc, the electric valve control device 70 inputs the pulse P in ascending order. The rotor 41 rotates in the valve closing direction. Or, if the target valve opening Dt is larger than the current valve opening Dc, the electric valve control device 70 inputs the pulse P in descending order. The rotor 41 rotates in the valve opening direction.

[0065] In step S270, the pulse P input by the electric valve control device 70 to the motor driver 77 is P[1], P[3], P[5], or P[7]. That is, when the last input pulse P to the motor driver 77 is P[2], the next input pulse P to the motor driver 77 is P[1] or P[3]. When the last input pulse P to the motor driver 77 is P[4], the next input pulse P to the motor driver 77 is P[3] or P[5]. When the last input pulse P to the motor driver 77 is P[6], the next input pulse P to the motor driver 77 is P[5] or P[7]. When the last input pulse P to the motor driver 77 is P[8], the next input pulse P to the motor driver 77 is P[7] or P[1]. And the electric valve control device 70 First counter C1 increments it by 1 (S280), sets the length E to the timer, and waits until the pulse input pause period elapses (S290).

[0066] When the pulse P last input to the motor driver 77 is any one of P[1], P[3], P[5], and P[7] (Y in S260), the electric valve control device 70 sets the length E in the timer and waits until the pulse input pause period elapses (S290).

[0067] During the pulse input pause period, the electric valve control device 70 does not input the pulse P to the motor driver 77, and the motor driver 77 does not supply drive current to the A-phase stator 61 and the B-phase stator 62. Since the pulse P last input to the motor driver 77 is any one of P[1], P[3], P[5], and P[7], the detent torque of the stepping motor 66 is relatively large during the pulse input pause period.

[0068] When the pulse input pause period elapses, the electric valve control device 70 sets the second counter C2 to 0 (S300) and returns to the determination of the first counter C1 (S220).

[0069] Then, the electric valve control device 70 repeats the input of the pulse P until the first counter C1 reaches the target number Nt (S220 to S300). When the first counter C1 reaches the target number Nt (Y in S220), the electric valve control device 70 stores the target valve opening Dt as the current valve opening Dc in the RAM and ends the process.

[0070] Next, an example of the change in the internal temperature of the motor driver 77 when the electric valve control device 70 inputs the pulse P of the target number Nt to the motor driver 77 when the ambient temperature Ta of the motor driver 77 is high will be described with reference to FIGS. 8 and 9.

[0071] Figures 8 and 9 are graphs showing the time variations of the number of pulses P input to the motor driver 77 and the internal temperature of the motor driver 77. Figure 8 shows the case where pulses P of the target number Nt are continuously input. Figure 9 shows the case where a pulse input pause period is provided every time pulses P of the unit number Nu are continuously input. The unit number Nu is smaller than the target number Nt. Figures 8A and 9A show the relationship between time and the number of pulses input to the motor driver. Figures 8B and 9B show the relationship between time and the internal temperature of the motor driver 77. In Figures 8A and 9A, the solid line indicates the period during which pulses P are being input, and the dashed line indicates the period during which pulses P are not being input.

[0072] As shown in Figure 8A, when the electric valve control device 70 continuously inputs pulses P of the target number Nt to the motor driver 77, as shown in Figure 8B, the internal temperature of the motor driver 77 rises as the electric valve control device 70 inputs pulses P. If the target number Nt is relatively large, the internal temperature of the motor driver 77 will exceed the upper limit temperature Tz.

[0073] As shown in Figure 9A, when the electric valve control device 70 provides a pulse input pause period every time it continuously inputs pulses P of the unit number Nu to the motor driver 77, as shown in Figure 9B, although the internal temperature of the motor driver 77 rises as the electric valve control device 70 inputs pulses P, the internal temperature decreases during the pulse input pause period. Therefore, the rise in the internal temperature of the motor driver 77 when inputting pulses P of the target number Nt can be suppressed, and it can be prevented that the internal temperature of the motor driver 77 exceeds the upper limit temperature Tz.

[0074] As described above, the electric valve device 1 according to this embodiment includes an electric valve 5 and an electric valve control device 70. The electric valve 5 has a stepping motor 66. The electric valve control device 70 controls the electric valve 5. The electric valve control device 70 has a computer 80 that inputs a pulse P to a motor driver 77 connected to the stepping motor 66. When the computer 80 receives a valve opening change command including the target valve opening Dt of the electric valve 5, it acquires a target number Nt, which is the number of pulses P to be input to the motor driver 77 in order to set the valve opening of the electric valve 5 to the target valve opening Dt. When the computer 80 determines that the ambient temperature Ta of the motor driver 77 is not high, it continuously inputs the pulses P of the target number Nt to the motor driver 77. When the computer 80 determines that the ambient temperature Ta of the motor driver 77 is high, it acquires a unit number Nu, which is the number of pulses P to be continuously input to the motor driver 77. When the computer 80 determines that the ambient temperature Ta is high, until the number of pulses P input to the motor driver 77 reaches the target number Nt, it continuously inputs the pulses P to the motor driver 77 by the unit number Nu each time, and provides a pulse input pause period each time the pulses P of the unit number Nu are input.

[0075] When the electric valve control device 70 determines that the ambient temperature Ta of the motor driver 77 is not high, it continuously inputs the pulses P of the target number Nt to the motor driver 77 at once. When the electric valve control device 70 determines that the ambient temperature Ta of the motor driver 77 is high, instead of inputting the pulses P of the target number Nt to the motor driver 77 at once, it inputs the pulses P to the motor driver 77 by the unit number Nu each time. Then, the electric valve control device 70 provides a pulse input pause period during which no pulse P is input each time the pulses P of the unit number Nu are input to the motor driver 77. Therefore, continuous operation of the motor driver 77 for a long time can be avoided, and an increase in the internal temperature of the motor driver 77 can be suppressed.

[0076] Also, the stepping motor 66 has a phase A stator 61 and a phase B stator 62. The motor driver 77 supplies drive currents corresponding to the pulse P to the phase A stator 61 and the phase B stator 62. The pulse P input to the motor driver 77 immediately before the pulse input pause period is a pulse P (P[1], P[3], P[5] or P[7]) that causes the motor driver 77 to supply a drive current to only the phase A stator 61 or only the phase B stator 62. By doing so, the detent torque of the stepping motor 66 during the pulse input pause period can be made relatively large. Therefore, it is possible to suppress the rotor 41 from rotating due to vibration or the like.

[0077] Also, the length E of the pulse input pause period is equal to or longer than the length of the time required for the input of the pulse P of the unit number Nu immediately before the pulse input pause period. By doing so, it is possible to prevent the length of the pulse input pause period from becoming insufficient with respect to the input of the continuous pulses P immediately before the pulse input pause period.

[0078] In the electric valve control device 70 described above, the unit number Nu is a fixed value and is stored in the ROM. The unit number Nu is not limited to a fixed value. In the electric valve control device 70, the unit number Nu may be a value corresponding to the ambient temperature Ta around the motor driver 77. In the electric valve control device 70, the unit number Nu may be made smaller as the ambient temperature Ta is higher. For example, when the ambient temperature Ta is equal to or higher than the high temperature determination threshold value Th and less than the high temperature determination threshold value Th + 10°C (Th ≤ Ta < Th + 10°C), the electric valve control device 70 sets the unit number Nu to 24, and when the ambient temperature Ta is equal to or higher than the high temperature determination threshold value Th + 10°C and less than the high temperature determination threshold value Th + 20°C (Th + 10°C ≤ Ta < Th + 20°C), the unit number Nu is set to 16, and when the ambient temperature Ta is equal to or higher than the high temperature determination threshold value Th + 20°C (Th + 20°C ≤ Ta), the unit number Nu is set to 8.

[0079] In the above-described electric valve control device 70, the length E of the pulse input pause period is a fixed value and is stored in the ROM. The length E is not limited to a fixed value. In the electric valve control device 70, the length E may be a value corresponding to the ambient temperature Ta around the motor driver 77. In the electric valve control device 70, the length E may be made longer as the ambient temperature Ta is higher. For example, when the ambient temperature Ta is equal to or higher than the high temperature determination threshold value Th and less than the high temperature determination threshold value Th + 10°C (Th ≤ Ta < Th + 10°C), the length E is set to 192 ms; when the ambient temperature Ta is equal to or higher than the high temperature determination threshold value Th + 10°C and less than the high temperature determination threshold value Th + 20°C (Th + 10°C ≤ Ta < Th + 20°C), the length E is set to 384 ms; and when the ambient temperature Ta is equal to or higher than the high temperature determination threshold value Th + 20°C (Th + 20°C ≤ Ta), the length E is set to 576 ms. Alternatively, the electric valve control device 70 may be configured to end the pulse input pause period when the ambient temperature Ta drops by a predetermined temperature (e.g., 1 to 10°C) during the pulse input pause period.

[0080] The embodiments of the present invention have been described above, but the present invention is not limited to the embodiments. For those skilled in the art, as long as it does not go against the spirit of the present invention, adding, deleting, or changing the design of components, or appropriately combining the features of the embodiments are all included in the scope of the present invention.

Explanation of Reference Numerals

[0081] 1… Electric valve device, 5… Electric valve, 10… Valve body, 11… Body member, 11a… Fitting hole, 11b… Through hole, 11d… Plane, 13… Connecting member, 14… Valve chamber, 15… First conduit, 16… Second conduit, 17… Valve port, 18… Valve seat, 20… Cam, 30… Valve body, 31… First shaft portion, 32… Second shaft portion, 33… Valve portion, 34… Step portion, 40… Driving mechanism, 41… Rotor, 41a… Fitting hole, 42… Valve shaft holder, 42a… Upper wall portion, 42b… Shaft hole, 42c… Female thread, 42s… Movable stopper, 43… Guide bush, 43a… Base portion, 43b… Support portion, 43c… Male thread, 43d… Plane, 44… Stopper member, 44a… Stopper body, 44c… Female thread, 44s… Fixed stopper, 45… Fixture, 45a… Fixed portion, 45b… Flange portion, 46… Washer, 47… Closing spring, 48… Return spring, 49… Stopper mechanism, 60… Stator, 61… A-phase stator, 61a… Pole tooth, 61b… Pole tooth, 61c… Coil, 62… B-phase stator, 62a… Pole tooth, 62b… Pole tooth, 62c… Coil, 66… Stepping motor, 70… Electric valve control device, 71… Substrate, 75… Non-volatile memory, 76… Communication device, 77… Motor driver, 80… Computer, 100… Air conditioning system, 101… Compressor, 102… Condenser, 103… Evaporator, 105… Pipe, 110… Air conditioning control device, 120… Wired communication bus, A1… Terminal, A2… Terminal, B1… Terminal, B2… Terminal, C1… First counter, C2… Second counter, G… Data table, L… Axis, Tz… Upper limit temperature

Claims

1. An electric valve control device for controlling an electric valve having a stepping motor, comprising: a control unit that inputs a pulse to a motor driver connected to the stepping motor; the motor driver supplies a drive current corresponding to the pulse to the stepping motor; when the control unit receives a valve opening degree change command including a target valve opening degree of the electric valve, the control unit obtains a target number, which is the number of pulses input to the motor driver to make the valve opening degree of the electric valve the target valve opening degree; when the control unit determines that the ambient temperature around the motor driver is not high, the control unit continuously inputs the target number of pulses to the motor driver at a set speed; when the control unit determines that the ambient temperature is high, the control unit obtains a unit number, which is the number of pulses continuously input to the motor driver, and continuously inputs pulses to the motor driver at the same speed as the set speed, one unit number at a time, until the number of pulses input to the motor driver reaches the target number, and provides a pulse input pause period every time the unit number of pulses is input. An electric valve control device characterized by this.

2. the stepping motor has a phase A stator and a phase B stator; the motor driver supplies a drive current corresponding to the pulse to the phase A stator and the phase B stator; the pulse input to the motor driver immediately before the pulse input pause period is a pulse that causes the motor driver to supply a drive current to only the phase A stator or only the phase B stator. The electric valve control device according to claim 1.

3. The length of the pulse input pause period is equal to or greater than the length of the time required for the input of the unit number of pulses immediately before the pulse input pause period. The electric valve control device according to claim 1 or claim 2.

4. An electric valve device having an electric valve having a stepping motor and the electric valve control device according to any one of claims 1 to 3.

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