Electric valve

Abstract

To provide a motor-operated valve advantageous for reduction of costs or reduction of maintenance work.SOLUTION: A motor-operated valve 100 includes an electric motor M for operating a valve body, and a control circuit 50. An open command and a close command to be input into an open command terminal T1 and a close command terminal T2 respectively are detected by an open command detection element (U1) and a close command detection element (U2) respectively. A common terminal mc of the electric motor M is connected to a first power terminal T3 by a common electric supply line Pc. An open terminal ma and a close terminal mb of the electric motor M are connected to a second power terminal T4 via an open electric supply line Pa and a close electric supply line Pb respectively. An open semiconductor switch Q1 and a close semiconductor switch Q2 are interposed in the open electric supply line Pa and the close electric supply line Pb respectively. The control circuit 50 conducts the open semiconductor switch Q1 when the open command detection element (U1) detects the input of the open command, and conducts the close semiconductor switch Q2 when the close command detection element (U2) detects the input of the close command.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] This invention relates to an electric valve.

Background Art

[0002] Patent Document 1 discloses an electric valve that opens and closes a valve by means of an electric motor having an open input terminal, a closed input terminal, and a common terminal. The open input terminal and the closed input terminal are connected to one terminal of an external power supply via an operation switch provided outside the electric valve, and the common terminal is connected to the other terminal of the external power supply. When the contact of the operation switch is connected to the open input terminal side, the open input terminal is connected to the external power supply and the electric motor is energized, causing the valve to operate in the open direction. When the contact of the operation switch is connected to the closed input terminal side, the closed input terminal is connected to the external power supply and the electric motor is energized, causing the valve to operate in the open direction.

[0003] A relay that operates by means of a fully open detection limit switch is interposed in the power supply line connected to the open input terminal inside the electric valve. When the fully open limit switch detects that the valve is fully open, the relay contact opens and power supply to the open input terminal is stopped. Similarly, a relay that operates by means of a fully closed detection limit switch is interposed in the other power supply line connected to the closed input terminal inside the electric valve. When the fully closed limit switch detects that the valve is fully closed, the relay contact opens and power supply to the closed input terminal is stopped.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Both the on / off switches and the relays interposed in the power supply lines open and close the power line between the external power source and the electric motor, requiring switching capacity (contact capacity) to handle high power switching. Consequently, this presents the challenge of high costs. In addition, because high current switching is performed by mechanical contacts, the number of operations before reaching the end of their lifespan is not high, and therefore, depending on the usage conditions, the replacement cycle for parts may be short, leading to increased maintenance effort.

[0006] Furthermore, electromagnetic noise generated by switching large currents may affect the operation of electronic circuits located near switching switches and motorized valves.

[0007] Therefore, one objective of this invention is to provide an electric valve that is advantageous in reducing costs or maintenance work.

[0008] Another object of this invention is to provide an electric valve that is advantageous in reducing the generation of electromagnetic noise. [Means for solving the problem]

[0009] To solve the above problems, this invention provides embodiments having the following exemplary features.

[0010] 1. A valve body that opens and closes the flow path, An electric motor that generates a driving force to actuate the valve body, and has an open terminal, a closed terminal and a common terminal, drives the valve body in the opening direction when current is passed between the open terminal and the common terminal, and drives the valve body in the closing direction when current is passed between the closed terminal and the common terminal, An open command terminal to which an open command that commands the valve body to move in the open direction is input from the outside, A closing command terminal to which a closing command that instructs the valve body to operate in the closing direction is input from an external source, First power terminal and second power terminal connected to an external power supply, An open command detection element for detecting the input of an open command to the open command terminal, A closing command detection element that detects the input of a closing command to the closing command terminal, A common power supply line connecting the aforementioned common terminal to the first power supply terminal, An open power supply wire connecting the open terminal to the second power supply terminal, A closed power supply line connecting the closed terminal to the second power supply terminal, An open semiconductor switch interposed in the open power supply line, A closed semiconductor switch interposed in the closed power supply line, An electric valve comprising: a control circuit that, when the open command detection element detects an input of an open command, causes the open semiconductor switch to conduct, and when the closed command detection element detects an input of a closed command, causes the closed semiconductor switch to conduct.

[0011] 2. The electric valve according to item 1, wherein the open command detection element includes an open command detection photocoupler including a light-emitting element connected between the open command terminal and the first power terminal, and the closed command detection element includes a closed command detection photocoupler including a light-emitting element connected between the closed command terminal and the first power terminal.

[0012] 3. The electric valve according to claim 1 or 2, further comprising a fully open detection means for detecting when the valve body has reached the fully open position, wherein the control circuit conducts on the open semiconductor switch if the open command detection element detects an input of an open command and the fully open detection means has not detected a fully open position, and otherwise disconnects the open semiconductor switch.

[0013] 4. The motorized valve according to claim 3, wherein the fully open detection means includes a fully open detection photocoupler including a light-emitting element connected between the first power terminal and the second power terminal, and a fully open detection limit switch that operates when the valve body reaches the fully open position to reverse the on / off state of the light-emitting element of the fully open detection photocoupler.

[0014] 5. The electric valve according to any one of claims 1 to 4, further comprising a fully closed detection means for detecting when the valve body has reached a fully closed position, wherein the control circuit conducts on the closed semiconductor switch if the closed command detection element detects an input of a closed command and the fully closed detection means has not detected full closure, and otherwise disconnects the closed semiconductor switch.

[0015] 6. The motorized valve according to claim 5, wherein the fully closed detection means includes a fully closed detection photocoupler including a light-emitting element connected between the first power terminal and the second power terminal, and a fully closed detection limit switch that operates when the valve body reaches the fully closed position to reverse the on / off state of the light-emitting element of the fully closed detection photocoupler.

[0016] 7. Further includes a spring for storing energy for emergency operation, and a storage completion detection means for detecting the completion of energy storage in the spring, The electric valve according to any one of claims 1 to 6, wherein the control circuit is configured such that the first power terminal and the second power terminal are connected to an external power source, and when the storage completion detection means has not detected that the spring has completed storing energy, it drives the electric motor by making one of the open semiconductor switch and the closed semiconductor switch conductive until the storage completion detection means detects that the spring has completed storing energy, thereby performing an initial operation to store energy in the spring.

[0017] 8. The electric valve according to item 7, wherein the storage completion detection means includes a storage completion detection photocoupler including a light-emitting element connected between the first power terminal and the second power terminal, and a storage completion detection limit switch that operates when the energy storage of the spring is complete to reverse the on / off state of the light-emitting element of the storage completion detection photocoupler.

[0018] 9. The electric valve according to any one of claims 1 to 8, wherein the electric motor is an AC electric motor, and is controlled by the control circuit, further comprising a zero-crossing type open drive circuit and a zero-crossing type closed drive circuit that cause the open semiconductor switch and the closed semiconductor switch to perform zero-crossing operation, respectively.

[0019] 10. The zero-crossing open drive circuit includes a light-emitting element that is switched on / off by the control circuit and a zero-crossing phototriac that photocouples with the light-emitting element, and is configured to drive the open semiconductor switch with the phototriac. The zero - cross type closed drive circuit includes a light - emitting element that is turned on / off by the control circuit, and a zero - cross type photo - triac that is optically coupled to the light - emitting element, and is configured to drive the closed semiconductor switch by the photo - triac. The motorized valve according to item 9.

Brief Description of the Drawings

[0020] [Figure 1] FIG. 1 is a cross - sectional view for explaining the configuration of a motorized valve according to an embodiment of the present invention. [Figure 2A-2C] FIGS. 2A, 2B, and 2C are perspective views of main parts for explaining the operation of the motorized valve. [Figure 3] FIG. 3 is an electrical circuit diagram for explaining an example of the electrical configuration of the motorized valve. [Figure 4] FIG. 4 shows a logic circuit for explaining an example of control by the control circuit of the motorized valve.

Embodiments for Carrying Out the Invention

[0021] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0022] [Structure of Motorized Valve] FIG. 1 is a cross - sectional view for explaining the configuration of a motorized valve 100 according to an embodiment of the present invention, and FIGS. 2A to FIGS. C are perspective views of main parts for explaining the operation.

[0023] This motorized valve 100 includes a valve body 1, an output shaft 2 to which the valve body 1 is coupled at the tip, an electric motor M that generates a driving force for operating the valve body 1, a transmission mechanism 60 that transmits the rotation of the electric motor M to the output shaft 2, a spring 4 coupled to the transmission mechanism 60, and an electromagnetic brake B. In this embodiment, the transmission mechanism 60 includes a planetary gear mechanism 61. The valve body 1 opens and closes a flow path 5 (see FIGS. 2A, etc.) by rotating the output shaft 2 (valve rod) by 90 degrees. The valve body 1 may be a ball valve or a butterfly valve.

[0024] A stopper plate 6 is fixed to the output shaft 2. A pair of stopper bolts 7 are positioned opposite the stopper plate 6. The pair of stopper bolts 7 are positioned to contact the stopper plate 6 at the fully open and fully closed positions of the output shaft 2, respectively, in order to restrict the rotation of the output shaft 2. The fully open position is the position in which the valve body 1 is fully open, and the fully closed position is the position in which the valve body 1 is fully closed.

[0025] The planetary gear mechanism 61 includes an internal gear 62 having internal and external teeth, a plurality of planetary gears 63 arranged to mesh with the internal teeth of the internal gear 62, a carrier 64 that rotatably supports each of these planetary gears 63, and a sun gear 65 that meshes with the plurality of planetary gears 63. The carrier 64 is fixed to the output shaft 2 and rotates integrally with the output shaft 2. The internal gear 62 is coupled to the output shaft 2 via a bearing 66 so as to be rotatable relative to the output shaft 2. A reduction gear 67 meshes with the external teeth of the internal gear 62, and a pinion 9 of the gearhead 8 meshes with this reduction gear 67. The sun gear 65 is fixed to the outer circumference of a sleeve 68 that passes through the output shaft 2. The sleeve 68 is coupled to the output shaft 2 via a bearing 69 so as to be rotatable relative to the output shaft 2. Therefore, the sun gear 65 is rotatable relative to the output shaft 2.

[0026] The intermediate gear 70 is fixed to the sleeve 68 together with the sun gear 65. That is, the sun gear 65 is connected to the intermediate gear 70 via the sleeve 68 and rotates integrally with the intermediate gear 70. The sun gear 65 and the intermediate gear 70 may be integrally formed.

[0027] The intermediate gear 70 meshes with the spring drive gear 71. The spring drive gear 71 is fixed to the central shaft 72 of the spring 4 (a mainspring in this embodiment). A gear 73 is provided on the spring central shaft 72 (spring drive shaft). This gear 73 meshes with another gear 75 fixed to the cam shaft 74. A cam 76 is fixed to the cam shaft 74, and a winding detection limit switch LS3 engages with this cam 76. When the winding of the spring 4 is complete, the winding detection limit switch LS3 is pushed by the cam 76 to detect the completion of the winding of the spring 4.

[0028] A reduction gear 77 is further meshed with the spring-driven gear 71, and a gear 78 fixed to the drive shaft of the electromagnetic brake B is meshed with this reduction gear 77. Specifically, the electromagnetic brake B includes a disc assembly coupled to the drive shaft of the gear 78, an armature that moves toward and away from the disc assembly, a field containing an excitation coil, and a coil spring that biases the armature toward away from the disc assembly. In the un-excited state, when the excitation coil is not energized, the spring force of the coil spring holds the armature away from the disc assembly, resulting in an un-braked state in which the disc assembly can rotate. When the excitation coil is energized, the armature is attracted to the field against the spring force of the coil spring and pressed against the disc assembly, thereby creating a braking state.

[0029] Multiple cams 79 are connected to the output shaft 2. Furthermore, multiple limit switches are provided, each corresponding to one of the multiple cams 79. The multiple limit switches include a fully open detection limit switch LS1 that operates when the output shaft 2 is in the fully open position, and a fully closed detection limit switch LS2 that operates when the output shaft 2 is in the fully closed position.

[0030] The electric motor M, electromagnetic brake B, transmission mechanism 60, etc., are housed within the housing 14, as shown by the dashed line. Inside the housing 14 is a wiring board 15 on which circuit components constituting the control unit K1, etc., are mounted.

[0031] [Operation of the electric valve] The general operation of this electric valve 100 is shown in Figures 2A to 2C, and is outlined below. For ease of understanding, in Figures 2A to 2C, which show multiple states, components whose rotation is restricted are indicated with diagonal lines.

[0032] When using the electric valve 100, the spring winding operation, i.e., the initial operation, shown in Figure 2A, is performed. In the initial state when the power is not turned on, the valve body 1 is in the initial position. The initial position is either the fully closed position or the fully open position. In the following description, the fully closed position will be used as the initial position. In the initial state, the stopper bolt 7 is in contact with the stopper plate 6, thereby restricting the rotation of the output shaft 2 in the closing direction (clockwise rotation in Figure 2A). In this state, the electromagnetic brake B is de-energized and put into a non-braking state, and the electric motor M is driven in the winding direction. As a result, the pinion 9 rotates, and this rotation is transmitted to the internal gear 62 via the reduction gear 67. Then the internal gear 62 rotates in the closing direction (clockwise direction in Figure 2A). This rotation is transmitted to the planetary gear 63. The orbit of the planetary gear 63, that is, the rotation of the carrier 64 fixed to the output shaft 2, is restricted by the stopper bolt 7, so the planetary gear 63 rotates on its axis without orbiting. The rotation of the planetary gear 63 causes the sun gear 65 to rotate in the winding direction (counterclockwise direction in Figure 2A). The rotation of the sun gear 65 is transmitted to the spring drive gear 71 via the intermediate gear 70, causing the spring central axis 72 to rotate. As a result, the spring 4 is wound up.

[0033] Once the spring 4 is fully wound up, the electromagnetic brake B is energized, causing it to enter a braking state. This braking force is transmitted to the spring's central shaft 72 via the reduction gear 77 and the spring drive gear 71, so that the spring 4 is held in its wound-up state. Furthermore, this braking force is transmitted from the spring drive gear 71 to the intermediate gear 70, thereby restricting the rotation of the sun gear 65, which is connected to the intermediate gear 70.

[0034] In this state, when the electric motor M is driven in the opening direction, the internal gear 62 rotates in the opening direction (counterclockwise in Figure 2B), as shown in Figure 2B. As a result, since the rotation of the sun gear 65 is restricted, the rotation of the internal gear 62 causes the planetary gear 63 to revolve around the sun gear 65, causing the carrier 64 to rotate. This causes the output shaft 2, which is fixed to the carrier 64, to rotate in the opening direction (counterclockwise in Figure 2B), and the valve body 1 opens. By stopping the power supply to the electric motor M, the valve body 1 can be stopped at any intermediate opening. From this state, when the electric motor M is driven in the closing direction, the internal gear 62 rotates in the closing direction (clockwise in Figure 2B). Since the rotation of the sun gear 65 is restricted, the planetary gear 63 revolves, causing the carrier 64 and the output shaft 2 fixed to it to rotate in the closing direction (clockwise in Figure 2B). This causes the valve body 1 to rotate in the closing direction. In this way, by driving the electric motor M in the closing and opening directions, the output shaft 2 can be rotated in the closing and opening directions, respectively, allowing the valve body 1 to be opened and closed, or its opening degree to be adjusted to any degree between fully open and fully closed.

[0035] When the electric motor M is not energized, the rotation of the internal gear 62 is restricted by the electric motor M, as shown in Figure 2C. In this state, when the power supply to the electromagnetic brake B is cut off and the brake becomes non-braked, the spring 4 is released. Then, the elastic restoring force of the spring 4 rotates the spring central axis 72. This rotation causes the sun gear 65 to rotate via the spring drive gear 71 and the intermediate gear 70. Since the rotation of the internal gear 62 is restricted, the rotation of the sun gear 65 causes the planetary gear 63 to revolve, and as a result, the output shaft 2 rotates in the closing direction (clockwise direction in Figure 2C) together with the carrier 64. The rotation of the output shaft 2 in the closing direction stops when the stopper plate 6 contacts the stopper bolt 7. In this way, in the event of a power outage, an emergency shutoff operation (emergency operation) can be achieved, which quickly guides the valve body 1 to the fully closed position by the restoring force of the spring 4.

[0036] [Electrical configuration of electric valves] Figure 3 is an electrical circuit diagram illustrating an example of the electrical configuration of the electric valve 100. The electric valve 100 has external connection terminals (T1 to T4) for external connections. The external connection terminals (T1 to T4) are typically connected to a control panel 20 via a cable 25. The control panel 20 is equipped with an AC power supply e (AC100V) as an external power supply and a command signal generator 21. In the illustrated example, the command signal generator 21 includes a common terminal c connected to one end of the AC power supply e, an open command output terminal a for outputting an open command, a closed command output terminal b for outputting a closed command, and a switch S1 that is in a disconnected state, either by connecting the common terminal c to the open command output terminal a or the closed command output terminal b, or by not connecting to either. The switch S1 may be a manual switch or a semiconductor switch controlled by a controller (not shown).

[0037] In this example, the external connection terminals include an open command terminal T1, a close command terminal T2, a first power supply terminal T3, and a second power supply terminal T4. The open command terminal T1 is an external connection terminal to which an open command is input from the outside, commanding the valve body 1 to operate in the opening direction. Therefore, the open command terminal T1 is connected to the open command output terminal a of the command signal generator 21. The close command terminal T2 is an external connection terminal to which a close command is input from the outside, commanding the valve body 1 to operate in the closing direction. Therefore, the close command terminal T2 is connected to the close command output terminal b of the command signal generator 21. The first power supply terminal T3 and the second power supply terminal T4 are connected to both ends of the AC power supply e, respectively.

[0038] An open command detection element is provided to detect the input of an open command to the open command terminal T1. In this embodiment, the open command detection element includes an open command detection photocoupler U1. The open command detection photocoupler U1 includes a light-emitting element 31 connected between the open command terminal T1 and the first power supply terminal T3, and a phototransistor 32 that is photocoupled with the light-emitting element 31 and conducts when the light-emitting element 31 emits light. The output of the phototransistor 32 is input to the control circuit 50. In this embodiment, the light-emitting element 31 includes two light-emitting diodes connected in antiparallel.

[0039] Similarly, a closed command detection element is provided to detect the input of a closed command to the closed command terminal T2. In this embodiment, the closed command detection element includes a closed command detection photocoupler U2. The closed command detection photocoupler U2 includes a light-emitting element 33 connected between the closed command terminal T2 and the first power supply terminal T3, and a phototransistor 34 that is photocoupled with the light-emitting element 33 and conducts when the light-emitting element 33 emits light. The output of the phototransistor 34 is input to the control circuit 50. In this embodiment, the light-emitting element 33 includes two light-emitting diodes connected in antiparallel.

[0040] In each photocoupler U1 and U2, when the light-emitting elements 31 and 33 are off, the phototransistors 32 and 34 are in the off state, and when the light-emitting elements 31 and 33 are emitting light, the phototransistors 32 and 34 are in the on state. The same applies to the other photocouplers U3, U4, and U5, which will be described below. Therefore, in the following, the state in which the light-emitting elements of photocouplers U1 to U5 are off will be referred to as the off state, and the state in which the light-emitting elements of photocouplers U1 to U5 are emitting light will be referred to as the on state.

[0041] A current-limiting resistor R1 is interposed between the open command detection photocoupler U1 and the open command terminal T1. Similarly, a current-limiting resistor R2 is interposed between the closed command detection photocoupler U2 and the closed command terminal T2. These resistors have the function of limiting the current by providing electrical resistance to the current from the AC power supply e, and can be made of resistors or capacitors. Capacitors have the advantage of allowing for smaller components.

[0042] The electric motor M has an open terminal ma, a closed terminal mb, and a common terminal mc. In this embodiment, the electric motor M is an AC electric motor. When current is supplied between the open terminal ma and the common terminal mc, the electric motor M rotates in a rotational direction that drives the valve body 1 in the opening direction (hereinafter, this type of rotation is referred to as "opening rotation"). When current is supplied between the closed terminal mb and the common terminal mc, the electric motor M rotates in a rotational direction that drives the valve body 1 in the closing direction (hereinafter, this type of rotation is referred to as "closing rotation"). A phase-advancing capacitor C1 is connected between the open terminal ma and the closed terminal mb. The common terminal mc is connected to the first power supply terminal T3 via a common power supply line Pc. No switches are provided on the common power supply line Pc, and therefore, the common terminal mc is always connected to one end of the AC power supply e. The open terminal ma is connected to the second power supply terminal T4 via an open power supply line Pa. An open semiconductor switch Q1 is interposed between the open terminal ma and the second power supply terminal T4 on the open power supply line Pa. The closed terminal mb is connected to the second power terminal T4 via a closed power supply line Pb. A closed semiconductor switch Q2 is interposed between the closed terminal mb and the second power terminal T4 in the closed power supply line Pb. In this embodiment, the open semiconductor switch Q1 and the closed semiconductor switch Q2 are composed of triacs.

[0043] A control signal is input to the control terminal of the open semiconductor switch Q1 (more specifically, the gate terminal of the triac) by a phototriac coupler U6. The phototriac coupler U6 includes a light-emitting element 41 that is turned on / off by the control circuit 50, and a phototriac 42 that is photocoupled with the light-emitting element 41 and becomes conductive when the light-emitting element 41 emits light. A series circuit of a current-limiting resistor R4 and the phototriac 42 is connected between the two terminals of the open semiconductor switch Q1, and the connection point between the resistor R4 and the phototriac 42 is connected to the control terminal of the open semiconductor switch Q1. When the phototriac 42 conducts, the open semiconductor switch Q1 conducts, power is supplied to the open terminal ma of the electric motor M, and the electric motor M rotates in the open direction. In this embodiment, the phototriac 42 is a zero-crossing type and constitutes a zero-crossing switch. The phototriac coupler U6 constitutes a zero-crossing type open drive circuit 51 that causes the open semiconductor switch Q1 to operate in zero-crossing mode.

[0044] Similarly, a control signal is input to the control terminal of the closed semiconductor switch Q2 (more specifically, the gate terminal of the triac) by the phototriac coupler U7. The phototriac coupler U7 includes a light-emitting element 43 that is turned on / off by the control circuit 50, and a phototriac 44 that is photocoupled with the light-emitting element 43 and becomes conductive when the light-emitting element 43 emits light. A series circuit of a current-limiting resistor R5 and the phototriac 44 is connected between the two terminals of the closed semiconductor switch Q2, and the connection point between the resistor R5 and the phototriac 44 is connected to the control terminal of the closed semiconductor switch Q2. When the phototriac 44 conducts, the closed semiconductor switch Q2 conducts, power is supplied to the closed terminal mb of the electric motor M, and the electric motor M rotates in the closed direction. In this embodiment, the phototriac 44 is a zero-crossing type and constitutes a zero-crossing switch. The phototriac coupler U7 constitutes a zero-crossing type closed drive circuit 52 that causes the closed semiconductor switch Q2 to operate in zero-crossing mode.

[0045] Since the phototriacs 42 and 44 are of the zero-crossing type, there is a period during which the illumination / exiting of the light-emitting elements 41 and 43 and the conduction / exiting of the phototriacs 42 and 44 do not strictly correspond. However, for the sake of explanation below, when the light-emitting elements 41 and 43 of the phototriac couplers U6 and U7 are off, we may consider the phototriacs 42 and 44 to be interrupted and refer to this as the "off state," and when the light-emitting elements 41 and 43 of the phototriac couplers U6 and U7 are emitting light, we may consider the phototriacs 42 and 44 to be conducting and refer to this as the "on state."

[0046] The electric valve 100 further includes a full-open detection means for detecting when the valve body 1 has reached the fully open position. In this embodiment, the full-open detection means includes a full-open detection photocoupler U3 and a full-open detection limit switch LS1. The full-open detection photocoupler U3 includes a light-emitting element 35 connected between a first power terminal T3 and a second power terminal T4, and a phototransistor 36 that photocouples with the light-emitting element 35 and becomes conductive when the light-emitting element 35 emits light. In this embodiment, the light-emitting element 35 includes two light-emitting diodes connected in antiparallel. The output of the phototransistor 36 is input to the control circuit 50. The full-open detection limit switch LS1 is connected between the terminals of the light-emitting element 35 and becomes conductive and short-circuits the terminals when the valve body 1 is not in the fully closed position. When the valve body 1 reaches the fully open position, the full-open detection limit switch LS1 activates and becomes interrupted, releasing the short circuit between the terminals of the light-emitting element 35 and causing the light-emitting element 35 to emit light. As a result, the fully open detection photocoupler U3 turns on (the phototransistor 36 becomes conductive), and the control circuit 50 is notified of the fully open detection.

[0047] The electric valve 100 also includes a fully closed detection means for detecting when the valve body 1 has reached the fully closed position. In this embodiment, the fully closed detection means includes a fully closed detection photocoupler U4 and a fully closed detection limit switch LS2. The fully closed detection photocoupler U4 includes a light-emitting element 37 connected between a first power terminal T3 and a second power terminal T4, and a phototransistor 38 that photocouples with the light-emitting element 37 and becomes conductive when the light-emitting element 37 emits light. In this embodiment, the light-emitting element 37 includes two light-emitting diodes connected in antiparallel. The output of the phototransistor 38 is input to the control circuit 50. The fully closed detection limit switch LS2 is connected between the terminals of the light-emitting element 37 and becomes conductive when the valve body 1 is not in the fully closed position, short-circuiting the terminals. When the valve body 1 reaches the fully closed position, the fully closed detection limit switch LS2 activates and becomes interrupted, releasing the short-circuit between the terminals of the light-emitting element 37 and causing the light-emitting element 37 to emit light. As a result, the fully closed detection photocoupler U4 turns on (the phototransistor 38 becomes conductive), and the control circuit 50 is notified that the gate is fully closed.

[0048] The electric valve 100 also includes a storage completion detection means for detecting when the winding of the spring 4, i.e., the storage of energy, is complete. In this embodiment, the storage completion detection means includes a winding detection photocoupler U5 (an example of a storage completion detection photocoupler) and a winding detection limit switch LS3 (an example of a storage completion detection limit switch). The winding detection photocoupler U5 includes a light-emitting element 39 connected between a first power terminal T3 and a second power terminal T4, and a phototransistor 40 that is photocoupled with the light-emitting element 39 and conducts when the light-emitting element 39 emits light. In this embodiment, the light-emitting element 39 includes two light-emitting diodes connected in antiparallel. The output of the phototransistor 40 is input to the control circuit 50. The winding detection limit switch LS3 is connected between the terminals of the light-emitting element 39, and when the spring winding is not complete, it conducts and short-circuits the terminals of the light-emitting element 39. When the winding of the spring 4 is complete, it operates and switches to an off state, releasing the short-circuit between the terminals of the light-emitting element 39 and causing the light-emitting element 39 to emit light. As a result, the winding detection photocoupler U5 turns ON (the phototransistor 40 becomes conductive), and the control circuit 50 is notified that the winding of the spring 4 is complete.

[0049] In this embodiment, the fully open detection photocoupler U3, the fully closed detection photocoupler U4, and the winding detection photocoupler U5 are connected in series between the first power terminal T3 and the second power terminal T4. In addition, a current-limiting resistor R3 is connected in series with the series circuit of these photocouplers U3, U4, and U5. The photocouplers U3, U4, and U5 may also be connected in parallel between the first power terminal T3 and the second power terminal T4.

[0050] Meanwhile, the first power supply unit PU1 is connected to the first power supply terminal T3 and the second power supply terminal T4. The first power supply unit PU1 includes a step-down transformer 55 that steps down AC100V from AC power supply e to, for example, AC24V, and a rectifier circuit 56 that rectifies the AC24V output by the step-down transformer 55 to generate a DC voltage VP1 of 24V. The DC voltage VP1 is used as a power source to operate the electromagnetic brake B.

[0051] Furthermore, the first power supply unit PU1 is connected to the second power supply unit PU2. The second power supply unit PU2 includes a DC-DC converter that steps down the DC24V generated by the first power supply unit PU1 to an operating voltage Vcc of, for example, DC5V. The operating voltage Vcc is supplied to the control circuit 50, as well as to the phototransistors 32, 34, 36, 38, and 40 of the photocouplers U1 to U5, and the light-emitting elements 41 and 43 of the phototriac couplers U6 and U7.

[0052] The control circuit 50 typically includes a microcomputer.

[0053] The phototransistors 32, 34, 36, 38, and 40 of the photocouplers U1 to U5 are connected to the input ports P1 to P5 of the control circuit 50. The input ports P1 to P5 are connected to ground potential via pull-down resistors R11 to R15, respectively, and H-level / L-level signals are input to the input ports P1 to P5 in accordance with the conduction / blocking of the phototransistors 32, 34, 36, 38, and 40 (i.e., in accordance with the on / off state of the photocouplers U1 to U5). The H level (high level) is the operating voltage Vcc, and the L level (low level) is the ground potential.

[0054] Meanwhile, the light-emitting elements 41 and 43 of the phototriac couplers U6 and U7 are connected to the output ports P11 and P12 of the control circuit 50, respectively. An operating voltage Vcc is supplied to each light-emitting element 41 and 43 via current-limiting resistors R16 and R17, and the on / off state of the light-emitting elements 41 and 43 (i.e., the on / off state of the phototriac couplers U6 and U7) is controlled by the control circuit 50 controlling the potential of the output ports P11 and P12. In addition, a brake drive circuit 53 for driving the electromagnetic brake B is connected to the output port P13 of the control circuit 50. The brake drive circuit 53 includes a power transistor Q3 connected in series with the electromagnetic brake B. The output port P13 of the control circuit 50 is connected to the gate of the power transistor Q3 via a current-limiting resistor R18. Therefore, by deriving a control signal to the output port of the control circuit 50, the power transistor Q3 can be turned on / off, and the electromagnetic brake B can be controlled to a braking state or an unbraked state. In the event of a power outage, the electromagnetic brake B will become deactivated due to the loss of power supply. Since the electromagnetic brake B is not frequently switched on and off, the problem of electromagnetic noise associated with switching on and off is minimal. Therefore, the power supply to and interruption of the electromagnetic brake B may be controlled by a relay, and the excitation / demagnetization of the relay coil may be controlled by power transistor Q3.

[0055] The control unit K1 shown in Figure 1 includes, for example, a control circuit 50, a first power supply unit PU1, a second power supply unit PU2, photocouplers U1 to U5, phototriac couplers U6 and U7, resistors R1 to R5, pull-down resistors R11 to R15, resistors R16 to R18, open semiconductor switch Q1, closed semiconductor switch Q2, power transistor Q3, and the like.

[0056] [Control Logic] Figure 4 shows a logic circuit illustrating an example of control by the control circuit 50. The control logic of this logic circuit is typically implemented by a microcomputer included in the control circuit 50 executing software. Of course, it goes without saying that the hardware (electronic circuits) constituting this logic circuit may also be provided in the control circuit 50.

[0057] The logic circuit within the control circuit 50 includes a NAND gate 81 for a phototriac coupler U6 that drives an open semiconductor switch Q1. The output of the NAND gate 81 is connected to an output port P11 which is connected to the light-emitting element 41 of the phototriac coupler U6.

[0058] The first input of the NAND gate 81 is connected to input port P1 and is supplied with an open command detection signal output by the open command detection photocoupler U1. The open command detection signal is high level if an open command is given and low level if no open command is given. The second input of the NAND gate 81 is connected to input port P3 and is supplied with a fully open detection signal output by the fully open detection photocoupler U3, inverted logically. The fully open detection signal is low level when fully open is not detected and high level when fully open is detected. Therefore, the second input of the NAND gate 81 is high level when fully open is not detected and low level when fully open is detected.

[0059] Therefore, when an open command is detected and a fully open state is not detected, the output of the NAND gate 81 becomes L level, the light-emitting element 41 of the phototriac coupler U6 lights up, and the phototriac coupler U6 turns ON. As a result, the open semiconductor switch Q1 conducts. Accordingly, the electric motor M rotates in the open direction.

[0060] When the electric motor M rotates in the opening direction and the valve body 1 reaches the fully open position, the fully open detection signal is inverted to a high level, causing the output of the NAND gate 81 to also invert to a high level. As a result, the light-emitting element 41 of the phototriac coupler U6 stops emitting light, and the phototriac coupler U6 turns off. Consequently, the open semiconductor switch Q1 is turned off, and the electric motor M stops driving.

[0061] If no open command is detected, the open command detection signal becomes low, so the output of the NAND gate 81 becomes high, the phototriac coupler U6 turns off, and therefore the open semiconductor switch Q1 is turned off, and the electric motor M stops driving.

[0062] The logic circuit within the control circuit 50 includes a NOR gate 82 for driving the light-emitting element 43 of the phototriac coupler U7 that drives the closed semiconductor switch Q2. An AND gate 83 is connected to the first input of the NOR gate 82, and an inverted winding completion detection signal (L level when spring winding is incomplete, H level when spring winding is complete) from the winding detection photocoupler U5 is input to the second input of the NOR gate 82 from the input port P5. The closed command detection signal provided to the input port P2 from the closed command detection photocoupler U2 is input to the first input of the AND gate 83. The fully closed detection signal provided to the input port P4 from the fully closed detection photocoupler U4 is input to the second input of the AND gate 83 inverted. Therefore, the output of the AND gate 83, i.e., the first input of the NOR gate 82, is H level when a closed command is detected and fully closed is not detected, and L level when a closed command is not detected or fully closed is detected. The output of the NOR gate 82 is connected to output port P12, which is connected to the light-emitting element 43 of the phototriac coupler U7.

[0063] Therefore, when a closing command is detected while the NOR gate 82 is not detected as fully closed, the output becomes L level. Accordingly, the phototriac coupler U7 turns on, the closed semiconductor switch Q2 conducts, and the electric motor M rotates in the closing direction.

[0064] Furthermore, the output of the NOR gate 82 is at a low level when the spring winding is incomplete. Accordingly, the phototriac coupler U7 turns on, the closed semiconductor switch Q2 conducts, and the electric motor M rotates in the closed direction. This performs the initial operation for winding the spring. After the winding of the spring 4 is completed by the initial operation, the on / off state of the phototriac coupler U7 is controlled according to the output of the AND gate 83.

[0065] The drive control of the electromagnetic brake B based on the output of the winding detection photocoupler U5 is as described above. When spring winding completion is not detected, the input to input port P5 is at an L level, the output port P13 is at an L level, and the power transistor Q3 is in a closed state. Therefore, the electromagnetic brake B is not energized, and the electromagnetic brake B is in a non-braking state. When spring winding completion is detected, the input to input port P5 becomes at an H level, the output port P13 becomes at an H level, and the power transistor Q3 conducts. As a result, the electromagnetic brake B is energized, and the electromagnetic brake B enters a braking state.

[0066] [Overall Operation Description] The operation of the electric valve 100 is outlined below.

[0067] When the electric valve 100 is not connected to the AC power supply e and is in an unpowered state (including during a power outage), the electromagnetic brake B is in a non-braking state, so the spring 4 is in a released state, and therefore the electric valve 100 is in its initial position. For example, if the initial position is the fully closed position, the fully open detection limit switch LS1 is in a conductive state, the fully closed detection limit switch LS2 is in a closed state, and the winding detection limit switch LS3 is in a conductive state.

[0068] From this state, when AC power e is connected to the first power terminal T3 and the second power terminal T4 and power is supplied (including recovery from a power outage), the initial operation begins. Until the initial operation is complete, the control circuit 50 does not accept input of either the closed command detection signal or the open command detection signal to input ports P1 and P2, treating them as invalid. Since the fully open detection limit switch LS1 is in the conductive state, the fully open detection photocoupler U3 is in the off state, and the fully open detection signal (input port P3) is at an L level, indicating that the fully open state has not been detected. Since the fully closed detection limit switch LS2 is in the off state, the fully closed detection photocoupler U4 is in the on state, and the fully closed detection signal (input port P4) is at an H level, indicating that the fully closed state has been detected. Since the winding detection limit switch LS3 is in the conductive state, the winding detection photocoupler U5 is in the off state, and the winding completion detection signal (input port P5) is at an L level, indicating that the winding completion has not been detected. Therefore, the electromagnetic brake B becomes non-braking, while the phototriac coupler U7 that drives the closed semiconductor switch Q2 turns ON, causing the electric motor M to rotate in the closed direction. This performs the initial operation for spring winding (see Figure 2A). When spring winding is complete, the winding detection limit switch LS3 turns OFF, and the winding detection photocoupler U5 turns ON, causing the winding completion detection signal (input port P5) to become H level, indicating that spring winding is complete. As a result, the electromagnetic brake B becomes braking, and the rotation of the electric motor M in the closed direction stops. Thus, the initial operation is completed.

[0069] Subsequently, when an open command is input from the control panel 20, the open command detection photocoupler U1 turns ON, and the open command detection signal (input port P1) becomes H level, indicating that an open command has been detected. At this time, the fully open detection limit switch LS1 is conducting, so the fully open detection photocoupler U3 is OFF, and the fully open detection signal (input port P3) is L level, indicating that the fully open position has not been detected. Therefore, the output of the NAND gate 81 becomes L level, and the phototriac coupler U6 that drives the open semiconductor switch Q1 turns ON. As a result, the electric motor M rotates in the open direction. When the input of the open command stops, the output of the NAND gate 81 reverses to H level, and the electric motor M stops. If the input of the open command continues until the valve body 1 reaches the fully open position, the fully open detection limit switch LS1 is interrupted, turning ON the fully open detection photocoupler U3. As a result, the output of the NAND gate 81 reverses to H level, and the electric motor M stops.

[0070] When the switch is driven from the fully closed position in the opening direction, the fully closed detection limit switch LS2 changes from the closed state to the conductive state, so the fully closed detection photocoupler U4 turns off, and the fully closed detection signal (input port P4) becomes an L level, indicating that the switch is not fully closed. In this state, when a closing command is input, the closing command detection photocoupler U2 turns on, and the closing command detection signal (input port P2) becomes an H level, indicating that the closing command has been detected. As a result, the output of the AND gate 83 becomes an H level, and the NOR gate 82 turns on the phototriac coupler U7 that drives the closed semiconductor switch Q2. This causes the electric motor M to rotate in the closing direction. When the input of the closing command is removed, the output of the AND gate 83 inverts to an L level, and accordingly the output of the NOR gate 82 inverts to an H level, so the electric motor M stops. If the closing command input continues until the valve body 1 reaches the fully closed position, the fully closed detection limit switch LS2 is interrupted, turning on the fully closed detection photocoupler U4, and the fully closed detection signal (input port P4) becomes a high level, indicating that the valve is fully closed. As a result, the output of the AND gate 83 is inverted to a low level, and accordingly the output of the NOR gate 82 is inverted to a high level, causing the electric motor M to stop.

[0071] If the power supply from the AC power source e is interrupted due to a power outage or the like, the electromagnetic brake B will no longer be energized and will become de-braked. As a result, the energy stored in the spring 4 is released, and this energy causes an emergency shutoff operation that moves the valve body 1 to the fully closed position.

[0072] [Summary of Embodiments] As described above, the electric valve 100 of this embodiment includes a valve body 1 for opening and closing a flow path, an electric motor M for operating the valve body 1, and a control circuit 50 for controlling the electric motor M. The electric motor M has an open terminal ma, a closed terminal mb, and a common terminal mc. When current is passed between the open terminal ma and the common terminal mc, it rotates in the opening direction to drive the valve body 1 in the opening direction, and when current is passed between the closed terminal mb and the common terminal mc, it rotates in the closing direction to drive the valve body 1 in the closing direction. An external open command to instruct the valve body 1 to operate in the opening direction is input to the open command terminal T1, and this input of an open command is detected by an open command detection element (U1). Similarly, an external close command to instruct the valve body 1 to operate in the closing direction is input to the close command terminal T2, and this close command is detected by a close command detection element (U2). An external AC power supply e is connected to the first power supply terminal T3 and the second power supply terminal T4. The common terminal mc of the electric motor M is connected to the first power terminal T3 by a common power supply line Pc. The open terminal ma of the electric motor M is connected to the second power terminal T4 via an open power supply line Pa, and its closed terminal mb is connected to the second power terminal T4 via a closed power supply line Pb. An open semiconductor switch Q1 is interposed in the open power supply line Pa, and a closed semiconductor switch Q2 is interposed in the closed power supply line Pb. The control circuit 50 conducts the open semiconductor switch Q1 when the open command detection element (U1) detects an open command input, and conducts the closed semiconductor switch Q2 when the closed command detection element (U2) detects a closed command input.

[0073] In this configuration, open and close commands from an external source are detected outside the power supply path to the electric motor M, and the conduction / disconnection of the open semiconductor switch Q1 and the closed semiconductor switch Q2 is controlled by the control circuit 50 in response to the detection of the open and close commands. As a result, the electric motor M is energized appropriately in response to the open and close commands, allowing the valve body 1 to be opened and closed.

[0074] Since the open semiconductor switch Q1 and the closed semiconductor switch Q2 do not have mechanical contacts, there is no high cost problem associated with using mechanical relays with large contact capacity, and there is no need for maintenance corresponding to the lifespan (number of operations) of the contacts. As a result, an electric valve 100 can be provided that is advantageous in reducing costs or maintenance work. In addition, opening and closing with semiconductor switches generates less electromagnetic noise than using relays with mechanical contacts, thereby reducing the impact on the operation of electronic circuits placed near the electric valve 100.

[0075] Furthermore, the command signal generator 21 of the control panel 20 is connected to the open command detection element (U1) and the closed command detection element (U2), and is located outside the power supply path to the electric motor M, so it does not switch large currents. Therefore, the generation of electromagnetic noise in the command signal generator 21 can be suppressed. Consequently, the impact on the operation of electronic circuits located near the control panel 20 can be reduced. In addition, even if the command signal generator 21 has mechanical contacts, it does not require a large contact capacity, so costs can be reduced. Also, because it does not require switching large currents, the number of operations until the end of its lifespan is increased, and maintenance effort can be reduced accordingly.

[0076] In the above embodiment, the open command detection element includes an open command detection photocoupler U1 having a light-emitting element 31 connected between the open command terminal T1 and the first power supply terminal T3. The closed command detection element includes a closed command detection photocoupler U2 having a light-emitting element 33 connected between the closed command terminal T2 and the first power supply terminal T3. With this configuration, open and closed commands can be detected and notified to the control circuit 50 while electrically isolating the external power supply (AC power supply e) from the control circuit 50.

[0077] Furthermore, in the above embodiment, the electric valve 100 further includes a fully open detection means (U3, LS1) for detecting when the valve body 1 has reached the fully open position. The control circuit 50 conducts the open semiconductor switch Q1 if the open command detection element (U1) detects an open command input and the fully open detection means (U3, LS1) have not detected a fully open position, and otherwise disconnects the open semiconductor switch Q1. As a result, if the valve body 1 is not in the fully open position, the electric motor M can be rotated in the opening direction to increase the opening degree of the valve body 1. The opening and closing of the open power supply line Pa according to whether the valve body 1 is in the fully open position is also performed by the open semiconductor switch Q1, and no relay with mechanical contacts is involved.

[0078] In the above embodiment, the fully open detection means includes a fully open detection photocoupler U3 including a light-emitting element 35 connected between a first power terminal T3 and a second power terminal T4, and a fully open detection limit switch LS1 that operates when the valve body 1 reaches the fully open position to reverse the on / off state of the light-emitting element 35 of the fully open detection photocoupler U3. This configuration allows for the detection of whether the valve body 1 is in the fully open position and notification to the control circuit 50 while electrically isolating the external power supply (AC power supply e) from the control circuit 50. Since the fully open detection limit switch LS1 does not open or close the open power supply line Pa, there is virtually no electromagnetic noise generated in conjunction with the operation of the fully open detection limit switch LS1. In the above embodiment, the fully open detection limit switch LS1 operates to short-circuit the terminals of the light-emitting element 35 to turn off (turn off) the light-emitting element 35 if the valve body 1 is not in the fully open position, and to release the short-circuit between the terminals of the light-emitting element 35 to turn on (light up) the light-emitting element 35 when the valve body 1 reaches the fully open position. However, this is just one example, and the logic can be reversed to design the device so that the light-emitting element 35 is turned on when it is in the fully open position and turned off when it is not in the fully open position.

[0079] Furthermore, in the above embodiment, the electric valve 100 further includes a fully closed detection means (U4, LS2) for detecting when the valve body 1 has reached the fully closed position. The control circuit 50 conducts the closed semiconductor switch Q2 if the closed command detection element (U2) detects the input of a closed command and the fully closed detection means (U4, LS2) does not detect that the valve is fully closed, and otherwise disconnects the closed semiconductor switch Q2. As a result, if the valve body 1 is not in the fully closed position, the electric motor M can be rotated in the closing direction to reduce the opening degree of the valve body 1. The opening and closing of the closed power supply line Pb according to whether the valve body 1 is in the fully closed position is also performed by the closed semiconductor switch Q2, and no relay with mechanical contacts is involved.

[0080] In the above embodiment, the fully closed detection means includes a fully closed detection photocoupler U4 including a light-emitting element 37 connected between a first power terminal T3 and a second power terminal T4, and a fully closed detection limit switch LS2 that operates when the valve body 1 reaches the fully closed position to reverse the on / off state of the light-emitting element 37 of the fully closed detection photocoupler U4. This configuration allows for the detection of whether the valve body 1 is in the fully closed position and notification to the control circuit 50, while electrically isolating the external power supply (AC power supply e) from the control circuit 50. Since the fully closed detection limit switch LS2 does not open or close the closed power supply line Pb, there is virtually no electromagnetic noise generated by the operation of the fully closed detection limit switch LS2. In the above embodiment, the fully closed detection limit switch LS2 operates to short-circuit the terminals of the light-emitting element 37 to turn off (turn off) the light-emitting element 37 if the valve body 1 is not in the fully closed position, and to release the short-circuit between the terminals of the light-emitting element 37 to turn on (light up) the light-emitting element 37 when the valve body 1 reaches the fully closed position. However, this is just one example, and the logic can be reversed to design the device so that the light-emitting element 37 is turned on when it is in the fully closed position and turned off when it is not in the fully closed position.

[0081] Furthermore, in the above embodiment, the electric valve 100 includes a spring 4 for storing energy for emergency operation and storage completion detection means (U5, LS3) for detecting the completion of energy storage in the spring 4.The control circuit 50, when the first power terminal T3 and the second power terminal T4 are connected to an external power source (AC power source e) and the storage completion detection means (U5, LS3) has not detected the completion of energy storage in the spring 4, drives the electric motor M to perform an initial operation to store energy in the spring 4 until the storage completion detection means (U5, LS3) detects the completion of energy storage in the spring 4.In the above embodiment, the emergency operation is an emergency closing operation in which the valve body 1 is closed by the energy of the spring 4, and the initial operation is an operation to rotate the electric motor M in the closing direction by conducting a closed semiconductor switch Q2.However, this is just one example, and the emergency operation may be an emergency opening operation in which the valve body 1 is opened by the energy of the spring 4.In this case, the initial operation may be an operation to rotate the electric motor M in the opening direction by conducting an open semiconductor switch Q1.

[0082] With this configuration, even during the initial operation for energy storage of spring 4, the opening and closing of the power supply lines Pa and Pb is performed by the open semiconductor switch Q1 or the closed semiconductor switch Q2, and relays with mechanical contacts are not involved.

[0083] In the above embodiment, the storage completion detection means includes a winding detection photocoupler U5 (storage completion detection photocoupler) which includes a light-emitting element 39 connected between a first power terminal T3 and a second power terminal T4, and a winding detection limit switch LS3 (storage completion detection limit switch) which operates when the energy storage of the spring 4 is complete to reverse the on / off state of the light-emitting element 39 of the winding detection photocoupler U5 (storage completion detection photocoupler). With this configuration, the incomplete / completed state of energy storage of the spring 4 can be detected and notified to the control circuit 50 while electrically isolating the external power supply (AC power supply e) and the control circuit 50. In the above embodiment, the winding detection limit switch LS3 operates to short-circuit the terminals of the light-emitting element 39 to turn off (turn off) the light-emitting element 39 if the spring winding (energy storage) is incomplete, and to release the short-circuit between the terminals of the light-emitting element 39 to turn on (light up) the light-emitting element 39 when the spring winding (energy storage) is complete. However, this is just one example, and the logic can be reversed to design the device so that the light-emitting element 39 is turned on when the spring winding (energy storage) is complete, and turned off when the spring winding (energy storage) is not complete.

[0084] Furthermore, in the above embodiment, the electric motor M is an AC electric motor. The electric valve 100 is controlled by the control circuit 50 and includes a zero-crossing type open drive circuit 51 and a zero-crossing type closed drive circuit 52 that cause the open semiconductor switch Q1 and the closed semiconductor switch Q2 to perform zero-crossing operation, respectively. With this configuration, the open semiconductor switch Q1 and the closed semiconductor switch Q2 turn on / off (zero-crossing operation) near zero volts of the AC voltage. This further reduces the generation of electromagnetic noise.

[0085] Furthermore, in the above embodiment, the zero-crossing open drive circuit 51 includes a light-emitting element 41 that is switched on / off by the control circuit 50 and a zero-crossing phototriac 42 that photocouples with the light-emitting element 41, and is configured to drive the open semiconductor switch Q1 with the phototriac 42. Similarly, the zero-crossing closed drive circuit 52 includes a light-emitting element 43 that is switched on / off by the control circuit 50 and a zero-crossing phototriac 44 that photocouples with the light-emitting element 43, and is configured to drive the closed semiconductor switch Q2 with the phototriac 44. With this configuration, power supply to the electric motor M can be controlled while electrically isolating the power supply lines Pa,Pb from the control circuit 50.

[0086] [Other embodiments] Although one embodiment of the present invention has been described above, the present invention can also be implemented in other forms.

[0087] For example, in the above-described embodiment, the open semiconductor switch Q1 is turned off when the fully open position is detected by the fully open detection means (U3, LS1). However, the limit switch LS1 may be interposed on the open power supply line Pa, and when the valve body 1 reaches the fully open position, the limit switch LS1 will cut off the open power supply line Pa. Similarly, in the above-described embodiment, the closed semiconductor switch Q2 is turned off when the fully closed position is detected by the fully closed detection means (U4, LS2). However, the limit switch LS2 may be interposed on the closed power supply line Pb, and when the valve body 1 reaches the fully closed position, the limit switch LS2 will cut off the closed power supply line Pb. In these configurations, electromagnetic noise is generated when the limit switches LS1 and LS2 operate at the fully open and / or fully closed positions. However, in applications where the opening degree of the valve body 1 is adjusted to an intermediate opening degree between fully closed and fully open, for example, the number of times the limit switches LS1 and LS2 operate is small, so this may not be a practical problem.

[0088] Furthermore, in the above-described embodiment, the completion of winding of the spring 4 is detected by the accumulation completion detection means (U5, LS3), and the operation of the electromagnetic brake B is controlled by the control circuit 50. However, a configuration in which a limit switch LS3 (or a relay that operates in accordance with the operation of the limit switch LS3) is interposed in the power supply line from the first power supply unit PU1 to the electromagnetic brake B is also possible. Since the power supply to the electromagnetic brake B is not turned on or off during the normal operation period after the initial operation is completed, the generation of electromagnetic noise associated with the on / off switching of the electromagnetic brake B may not be a substantial problem.

[0089] Furthermore, in the embodiment described above, the electromagnetic brake B is designed to de-brake when the external power supply is cut off, releasing the energy of the spring 4, but this is just one example. For example, the electromagnetic brake B can be controlled based on the detection signal of a sensor such as an earthquake sensor. In order to maintain operation that responds to the sensor even in the event of a power outage, an internal power supply should be provided that maintains power supply to the control circuit 50 and the electromagnetic brake B even when the external power supply is cut off. The internal power supply is typically a secondary battery or an electric double-layer capacitor. When such an internal power supply is provided, an unexcited type electromagnetic brake B that is in a braking state when unexcited can also be used.

[0090] Furthermore, although the above-described embodiment shows a configuration that includes a spring 4 for emergency operation and an electromagnetic brake B for activating it, this invention may also be applied to electric valves that do not have these features.

[0091] Furthermore, various design modifications can be made within the scope of the matters described in the patent claims. [Explanation of symbols]

[0092] 1: Valve body 4: Spring 20: Control Panel 21: Command signal generator 31, 33, 35, 37, 39: Light-emitting elements 32, 34, 36, 38, 40: Phototransistors 41, 43: Light-emitting element 42,44: Phototriac 50: Control circuit 51: Zero-crossing type open drive circuit 52: Zero-crossing type closed drive circuit 53: Brake drive circuit 81: NAND gate 82: NOR Gate 83: AND Gate 100: Electric valve LS1: Fully open detection limit switch LS2: Fully closed detection limit switch LS3: Winding detection limit switch M: Electric motor Pa: Open feeder line Pb: Closed feed line PC: Common power line Q1: Open semiconductor switch Q2: Closed semiconductor switch Q3: Power transistor T1: Open command terminal T2: Close command terminal T3: 1st power supply terminal T4: 2nd power supply terminal U1: Open command detection photocoupler U2: Closed command detection photocoupler U3: Fully open detection photocoupler U4: Fully enclosed detection photocoupler U5: Winding detection photocoupler U6: Phototriac coupler U7: Phototriac coupler e: AC power supply ma: open terminal mb: Closed terminal mc: Common terminal

Claims

1. A valve body that opens and closes the flow path, An electric motor that generates a driving force to actuate the valve body, and has an open terminal, a closed terminal and a common terminal, drives the valve body in the opening direction when current is passed between the open terminal and the common terminal, and drives the valve body in the closing direction when current is passed between the closed terminal and the common terminal, An open command terminal to which an open command that commands the valve body to move in the open direction is input from the outside, A closing command terminal to which a closing command that instructs the valve body to operate in the closing direction is input from an external source, First power terminal and second power terminal connected to an external power supply, An open command detection element for detecting the input of an open command to the open command terminal, A closing command detection element that detects the input of a closing command to the closing command terminal, A common power supply line connecting the common terminal to the first power supply terminal, An open power supply wire connecting the open terminal to the second power supply terminal, A closed power supply line connecting the closed terminal to the second power supply terminal, An open semiconductor switch interposed in the open power supply line, A closed semiconductor switch interposed in the closed power supply line, A control circuit that, when the open command detection element detects an open command input, causes the open semiconductor switch to conduct, and when the closed command detection element detects a closed command input, causes the closed semiconductor switch to conduct. A spring that stores energy for emergency action, A storage completion detection means for detecting the completion of energy storage in the spring, Includes, The control circuit is an electric valve in which, when the first power terminal and the second power terminal are connected to an external power source and the storage completion detection means has not detected that the energy storage of the spring is complete, the control circuit drives the electric motor to perform an initial operation to store energy in the spring by making one of the open semiconductor switch and the closed semiconductor switch conductive until the storage completion detection means detects that the energy storage of the spring is complete.

2. The open command detection element includes an open command detection photocoupler which includes a light-emitting element connected between the open command terminal and the first power supply terminal. The electric valve according to claim 1, wherein the closed command detection element includes a closed command detection photocoupler that includes a light-emitting element connected between the closed command terminal and the first power supply terminal.

3. The system further includes a fully open detection means for detecting when the valve body has reached the fully open position, The electric valve according to claim 1, wherein the control circuit conducts on the open semiconductor switch if the open command detection element detects an input of an open command and the fully open detection means does not detect a fully open state, and otherwise shuts off the open semiconductor switch.

4. The electric valve according to claim 3, wherein the fully open detection means includes a fully open detection photocoupler including a light-emitting element connected between the first power terminal and the second power terminal, and a fully open detection limit switch that operates when the valve body reaches the fully open position to reverse the on / off state of the light-emitting element of the fully open detection photocoupler.

5. The system further includes a fully closed detection means for detecting when the valve body has reached the fully closed position, The electric valve according to claim 1, wherein the control circuit conducts on the closed semiconductor switch if the closed command detection element detects the input of a closed command and the fully closed detection means does not detect that the valve is fully closed, and otherwise shuts off the closed semiconductor switch.

6. The electric valve according to claim 5, wherein the fully closed detection means includes a fully closed detection photocoupler including a light-emitting element connected between the first power terminal and the second power terminal, and a fully closed detection limit switch that operates when the valve body reaches the fully closed position to reverse the on / off state of the light-emitting element of the fully closed detection photocoupler.

7. The electric valve according to claim 1, wherein the storage completion detection means includes a storage completion detection photocoupler including a light-emitting element connected between the first power terminal and the second power terminal, and a storage completion detection limit switch that operates when the energy storage of the spring is completed to reverse the on / off state of the light-emitting element of the storage completion detection photocoupler.

8. The aforementioned electric motor is an AC electric motor, The electric valve according to any one of claims 1 to 7, further comprising a zero-crossing type open drive circuit and a zero-crossing type closed drive circuit controlled by the control circuit to perform zero-crossing operation on the open semiconductor switch and the closed semiconductor switch, respectively.

9. The zero-crossing open-drive circuit includes a light-emitting element that is switched on / off by the control circuit and a zero-crossing phototriac that photocouples with the light-emitting element, and is configured to drive the open-semiconductor switch with the phototriac. The electric valve according to claim 8, wherein the zero-crossing closed drive circuit includes a light-emitting element that is switched on / off by the control circuit and a zero-crossing phototriac that photocouples with the light-emitting element, and is configured to drive the closed semiconductor switch by the phototriac.

10. A valve body for opening and closing a flow path, An AC electric motor that generates a driving force to actuate the valve body, and has an open terminal, a closed terminal and a common terminal, drives the valve body in the opening direction when current is passed between the open terminal and the common terminal, and drives the valve body in the closing direction when current is passed between the closed terminal and the common terminal, An open command terminal to which an open command that commands the valve body to move in the open direction is input from the outside, A closing command terminal to which a closing command that instructs the valve body to operate in the closing direction is input from an external source, First power terminal and second power terminal connected to an external power supply, An open command detection element for detecting the input of an open command to the open command terminal, A closing command detection element that detects the input of a closing command to the closing command terminal, A common power supply line connecting the common terminal to the first power supply terminal, An open power supply wire connecting the open terminal to the second power supply terminal, A closed power supply line connecting the closed terminal to the second power supply terminal, An open semiconductor switch interposed in the open power supply line, A closed semiconductor switch interposed in the closed power supply line, A control circuit that, when the open command detection element detects an open command input, causes the open semiconductor switch to conduct, and when the closed command detection element detects a closed command input, causes the closed semiconductor switch to conduct. A zero-crossing type open drive circuit and a zero-crossing type closed drive circuit are controlled by the aforementioned control circuit to perform zero-crossing operation on the open semiconductor switch and the closed semiconductor switch, respectively. Includes, The zero-crossing open-drive circuit includes a light-emitting element that is switched on / off by the control circuit and a zero-crossing phototriac that photocouples with the light-emitting element, and is configured to drive the open-semiconductor switch with the phototriac. The zero-crossing type closed drive circuit includes a light-emitting element that is switched on / off by the control circuit and a zero-crossing type phototriac that photocouples with the light-emitting element, and is configured to drive the closed semiconductor switch by the phototriac, in an electrically operated valve.

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