Motor-operated 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 an electric motor having an open input terminal, a close input terminal, and a common terminal. The open input terminal and the close 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, and the valve operates in the open direction. When the contact of the operation switch is connected to the close input terminal side, the close input terminal is connected to the external power supply and the electric motor is energized, and the valve operates in the open direction.

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

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 switch and the relay installed in the power supply line open and close the power line between the external power supply and the electric motor, so an on-off capacity (contact capacity) corresponding to the on-off of high power is required. Accordingly, there is a problem that the cost increases. In addition, due to the opening and closing of a large current by a mechanical contact, the number of operating times until the end of life is not large. Therefore, depending on the usage state, the replacement cycle of parts becomes short, and the maintenance work becomes troublesome.

[0006] In addition, the electromagnetic noise generated with the opening and closing of a large current may affect the operation of the electronic circuit arranged near the on-off switch or the electric valve.

[0007] Therefore, one object of the present invention is to provide an electric valve advantageous for cost reduction or reduction of maintenance work.

[0008] Another object of the present invention is to provide an electric valve advantageous for reduction of generation of electromagnetic noise.

Means for Solving the Problems

[0009] In order to solve the above problems, the present invention provides an embodiment having the features exemplified below.

[0010] 1. A valve body for opening and closing a flow path, a driving force for operating the valve body is generated, and it has an open terminal, a closed terminal, and a common terminal. When power is supplied between the open terminal and the common terminal, the valve body is driven in the open direction, and when power is supplied between the closed terminal and the common terminal, the valve body is driven in the closed direction. An electric motor, an open command terminal to which an open command for instructing the operation of the valve body in the open direction is input from the outside, a close command terminal to which a close command for instructing the operation of the valve body in the close direction is input from the outside, a first power supply terminal and a second power supply 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 close command detection element for detecting the input of a close command to the close command terminal, A common power supply line connecting the common terminal to the first power supply terminal, An open power supply line 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 turns on the open semiconductor switch when the open command detection element detects an input of an open command, and turns on the closed semiconductor switch when the closed command detection element detects an input of a closed command, including an electric valve.

[0011] 2. 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 supply 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 supply terminal. The electric valve according to item 1.

[0012] 3. Further including a fully open detection means for detecting that the valve body has reached the fully open position, and the control circuit turns 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 full opening, and otherwise shuts off the open semiconductor switch. The electric valve according to item 1 or 2.

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

[0014] 5. Further including a fully closed detection means for detecting that the valve body has reached the fully closed position, and the control circuit turns on the closed semiconductor switch if the closed command detection element detects an input of a closed command and the fully closed detection means does not detect full closing, and otherwise shuts off the closed semiconductor switch. The electric valve according to any one of items 1 to 4.

[0015] 6. 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 and reverses the on / off of the light emitting element of the fully closed detection photocoupler. The electric valve according to item 5.

[0016] 7. Further includes a spring for accumulating energy for emergency operation, and an accumulation completion detection means for detecting completion of energy accumulation of the spring. When the first power terminal and the second power terminal are connected to an external power supply and the accumulation completion detection means has not detected completion of energy accumulation of the spring, the control circuit drives the electric motor by conducting one of a predetermined one of the open semiconductor switch and the closed semiconductor switch until the accumulation completion detection means detects completion of energy accumulation of the spring, and executes an initial operation for accumulating energy in the spring. The electric valve according to any one of items 1 to 6.

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

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

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

Brief Description of the Drawings

[0020]

Figure 1

Figures 2A - 2C

Figure 3

Figure 4

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

[0023] This motor-operated valve 100 includes a valve body 1, an output shaft 2 having the valve body 1 coupled to its 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. The transmission mechanism 60 includes a planetary gear mechanism 61 in this embodiment. 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, for example. 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 arranged so as to face the stopper plate 6. The pair of stopper bolts 7 are arranged to abut against the stopper plate 6 at the fully open position and the fully closed position of the output shaft 2 respectively, so as to restrict the rotation of the output shaft 2. The fully open position is the position where the valve body 1 is in the fully open state, and the fully closed position is the position where the valve body 1 is in the fully closed state.

[0025] The planetary gear mechanism 61 includes an internal gear 62 having internal teeth 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 plurality of 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 so as to be relatively rotatable via a bearing 66. A reduction gear 67 meshes with the external teeth of the internal gear 62, and a pinion 9 of the gear head 8 meshes with the reduction gear 67. The sun gear 65 is fixed to the outer periphery of a sleeve 68 that passes through the output shaft 2. The sleeve 68 is coupled to the output shaft 2 so as to be relatively rotatable via a bearing 69. Therefore, the sun gear 65 is relatively rotatable with respect to the output shaft 2.

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

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

[0028] The spring drive gear 71 further meshes with a reduction gear 77, and a gear 78 fixed to the drive shaft of the electromagnetic brake B meshes with this reduction gear 77. Specifically, the electromagnetic brake B includes a disk assembly coupled to the drive shaft of the gear 78, an armature that contacts and separates from the disk assembly, a field incorporating an excitation coil, and a coil spring that biases the armature in a direction away from the disk assembly. In the non-excited state where the excitation coil is not energized, the armature is held in a state separated from the disk assembly by the spring force of the coil spring, and the disk assembly is in a non-braking state where it 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 disk assembly, thereby bringing the brake into a braking state.

[0029] A plurality of cams 79 are coupled to the output shaft 2. Further, a plurality of limit switches corresponding to the plurality of cams 79 are provided. The plurality of limit switches include an open detection limit switch LS1 that operates at the fully open position of the output shaft 2, a fully closed detection limit switch LS2 that operates at the fully closed position of the output shaft 2, and the like.

[0030] The electric motor M, the electromagnetic brake B, the transmission mechanism 60, etc. are housed in the housing 14 as shown by the two-dot chain line. A wiring board 15 on which circuit components constituting the control unit K1 and the like are mounted is housed in the housing 14.

[0031] [Operation of Electric Valve] The outline of the operation of this electric valve 100 is shown in FIGS. 2A to 2C and is as outlined below. For ease of understanding, in FIGS. 2A to 2C showing a plurality of states, the members whose rotation is restricted are hatched.

[0032] When the electric valve 100 is used, the spring winding operation shown in FIG. 2A, that is, the initial operation, is performed. In the initial state where 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. Hereinafter, the fully closed position will be described as the initial position. In the initial state, the stopper bolt 7 abuts against the stopper plate 6, whereby the rotation of the output shaft 2 in the closing direction (clockwise rotation in FIG. 2A) is restricted. In this state, the electromagnetic brake B is de-energized and in the non-braking state, and the electric motor M is driven in the winding-up direction. Thereby, the pinion 9 rotates, and the 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 FIG. 2A). This rotation is transmitted to the planetary gear 63. The revolution 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 without revolving. The rotation of the planetary gear 63 causes the sun gear 65 to rotate in the winding-up direction (counterclockwise direction in FIG. 2A). The rotation of the sun gear 65 is transmitted to the spring drive gear 71 via the relay gear 70, causing the rotation of the spring central axis 72. Thereby, the spring 4 is wound up.

[0033] When the winding-up of the spring 4 is completed, the electromagnetic brake B is energized, so that the electromagnetic brake B becomes the braking state. The braking force is transmitted to the spring central axis 72 via the reduction gear 77 and the spring drive gear 71, so the spring 4 is held in the wound-up state. Further, the braking force is transmitted from the spring drive gear 71 to the relay gear 70, restricting the rotation of the sun gear 65 connected to the relay gear 70.

[0034] In this state, when the electric motor M is driven in the opening direction, as shown in FIG. 2B, the internal gear 62 rotates in the opening direction (counterclockwise direction in FIG. 2B). Then, 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, thereby causing the carrier 64 to rotate. As a result, the output shaft 2 fixed to the carrier 64 rotates in the opening direction (counterclockwise direction in FIG. 2B), and the valve body 1 opens. If the power supply to the electric motor M is stopped, the valve body 1 can be stopped at an arbitrary intermediate opening degree. From this state, if the electric motor M is driven in the closing direction, the internal gear 62 rotates in the closing direction (clockwise direction in FIG. 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 thereto to rotate in the closing direction (clockwise direction in FIG. 2B). Thereby, the valve body 1 rotates in the closing direction. Thus, 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, and the valve body 1 can be opened and closed, or the opening degree thereof can be adjusted to an arbitrary opening degree between fully open and fully closed.

[0035] When the electric motor M is not energized, as shown in FIG. 2C, the rotation of the internal gear 62 is restricted by the electric motor M. In this state, when the power supply to the electromagnetic brake B is cut off and it becomes a non-braking state, 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 relay 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 thereby the output shaft 2 rotates in the closing direction (clockwise direction in FIG. 2C) together with the carrier 64. The rotation of the output shaft 2 in the closing direction stops when the stopper plate 6 abuts against the stopper bolt 7. Thus, at the time of a power failure, the emergency shut-off operation (emergency operation) that quickly guides the valve body 1 to the fully closed position can be achieved by the restoring force of the spring 4.

[0036] [Electrical Configuration of Electric Valve] FIG. 3 is an electric circuit diagram for explaining an example of the electrical configuration of the electric valve 100. The electric valve 100 has external connection terminals (T1 to T4) for external connection. The external connection terminals (T1 to T4) are typically connected to the control panel 20 via the cable 25. The control panel 20 is provided 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 close command output terminal b for outputting a close command, and a switch S1 that can connect the common terminal c to the open command output terminal a or the close command output terminal b or be in an off state where it is not connected to either. The switch S1 may be a manual switch or a semiconductor switch controlled by a controller (not shown).

[0037] The external connection terminals include, in this example, 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 for commanding the operation of the valve body 1 in the open direction is input from the outside. 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 for commanding the operation of the valve body 1 in the close direction is input from the outside. 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 respectively connected to both ends of the AC power supply e.

[0038] An open command detection element is provided to detect the input of an open command to the open command terminal T1. The open command detection element includes, in this embodiment, 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 optically coupled to 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. The light emitting element 31 includes, in this embodiment, two light emitting diodes connected in reverse parallel.

[0039] Similarly, a close command detection element is provided to detect the input of a close command to the close command terminal T2. In this embodiment, the close command detection element includes a close command detection photocoupler U2. The close command detection photocoupler U2 includes a light emitting element 33 connected between the close command terminal T2 and the first power supply terminal T3, and a phototransistor 34 that is optically coupled to 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 reverse parallel.

[0040] In each of the photocouplers U1 and U2, when the light emitting elements 31 and 33 are turned 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 described below. Therefore, hereinafter, the state in which the light emitting elements of the photocouplers U1 to U5 are turned off is referred to as the off state, and the state in which the light emitting elements of the photocouplers U1 to U5 are emitting light is 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 close command detection photocoupler U2 and the close command terminal T2. These resistors have a function of providing electrical resistance to the current from the AC power supply e to limit the current, and can be composed of resistors, or can also be composed of capacitors. Capacitors have the advantage of making the elements smaller.

[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 alternating current motor. When energized between the open terminal ma and the common terminal mc, the electric motor M rotates in the rotational direction that drives the valve body 1 in the opening direction (hereinafter, such rotation is referred to as "rotation in the opening direction"). When energized between the closed terminal mb and the common terminal mc, the electric motor M rotates in the rotational direction that drives the valve body 1 in the closing direction (hereinafter, such rotation is referred to as "rotation in the closing direction"). A phase advance 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 the common power supply line Pc. No switch is provided on the common power supply line Pc, and thus the common terminal mc is always connected to one end of the alternating current power supply e. The open terminal ma is connected to the second power supply terminal T4 via the 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 supply terminal T4 via the closed power supply line Pb. A closed semiconductor switch Q2 is interposed between the closed terminal mb and the second power supply terminal T4 on the closed power supply line Pb. In this embodiment, the open semiconductor switch Q1 and the closed semiconductor switch Q2 are constituted by triacs.

[0043] A control signal is input to the control terminal of the semiconductor switch Q1 (more specifically, the gate terminal of the triac) by the optotriac coupler U6. The optotriac coupler U6 includes a light-emitting element 41 that is turned on / off by the control circuit 50, and an optotriac 42 that is optically coupled to the light-emitting element 41 and conducts when the light-emitting element 41 emits light. A series circuit of a current-limiting resistor R4 and the optotriac 42 is connected between both terminals of the semiconductor switch Q1, and the connection point of the resistor R4 and the optotriac 42 is connected to the control terminal of the semiconductor switch Q1. When the optotriac 42 conducts, the 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 optotriac 42 is a zero-cross type and constitutes a zero-cross switch. And the optotriac coupler U6 constitutes a zero-cross type open drive circuit 51 that zero-cross operates the semiconductor switch Q1.

[0044] Similarly, a control signal is input to the control terminal of the semiconductor switch Q2 (more specifically, the gate terminal of the triac) by the optotriac coupler U7. The optotriac coupler U7 includes a light-emitting element 43 that is turned on / off by the control circuit 50, and an optotriac 44 that is optically coupled to the light-emitting element 43 and conducts when the light-emitting element 43 emits light. A series circuit of a current-limiting resistor R5 and the optotriac 44 is connected between both terminals of the semiconductor switch Q2, and the connection point of the resistor R5 and the optotriac 44 is connected to the control terminal of the semiconductor switch Q2. When the optotriac 44 conducts, the 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 optotriac 44 is a zero-cross type and constitutes a zero-cross switch. And the optotriac coupler U7 constitutes a zero-cross type closed drive circuit 52 that zero-cross operates the semiconductor switch Q2.

[0045] Since the photo-triacs 42 and 44 are of the zero-crossing type, there is a period during which the lighting / extinguishing of the light-emitting elements 41 and 43 does not exactly correspond to the conduction / blocking of the photo-triacs 42 and 44. However, hereinafter, for convenience of explanation, when the light-emitting elements 41 and 43 of the photo-triac couplers U6 and U7 are extinguished, it is regarded as the "off state" assuming that the photo-triacs 42 and 44 are blocked, and when the light-emitting elements 41 and 43 of the photo-triac couplers U6 and U7 are emitting light, it may be regarded as the "on state" assuming that the photo-triacs 42 and 44 are conducting.

[0046] The motor-operated valve 100 further includes an open detection means for detecting that the valve body 1 has reached the fully open position. In this embodiment, the open detection means includes an open detection photo-coupler U3 and an open detection limit switch LS1. The open detection photo-coupler U3 includes a light-emitting element 35 connected between a first power supply terminal T3 and a second power supply terminal T4, and a photo-transistor 36 that is optically coupled to the light-emitting element 35 and conducts when the light-emitting element 35 emits light. In this embodiment, the light-emitting element 35 includes two light-emitting diodes connected in reverse parallel. The output of the photo-transistor 36 is input to the control circuit 50. The open detection limit switch LS1 is connected between the terminals of the light-emitting element 35 and is in a conductive state and shorts between its terminals except in the fully closed position. The open detection limit switch LS1 operates and becomes a blocking state when the valve body 1 reaches the fully open position, releases the short circuit between the terminals of the light-emitting element 35, and causes the light-emitting element 35 to emit light. Thereby, the open detection photo-coupler U3 becomes an on state (the photo-transistor 36 is in a conductive state), and the control circuit 50 is notified of the open detection.

[0047] The motor-operated valve 100 also includes a fully closed detection means for detecting that 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 the first power supply terminal T3 and the second power supply terminal T4, and a phototransistor 38 that is optically coupled to the light-emitting element 37 and is conductive when the light-emitting element 37 emits light. In this embodiment, the light-emitting element 37 includes two light-emitting diodes connected in reverse parallel. 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 is in a conductive state at positions other than the fully closed position, shorting the terminals. When the valve body 1 reaches the fully closed position, the fully closed detection limit switch LS2 operates to be in a cut-off state, releasing the short circuit between the terminals of the light-emitting element 37 and causing the light-emitting element 37 to emit light. This causes the full-close detection photocoupler U4 to be turned on (the phototransistor 38 is in a conductive state), and the control circuit 50 is notified that the full-close detection has been made.

[0048] The motor-operated valve 100 also includes an accumulation completion detection means for detecting the completion of winding up the spring 4, i.e., the completion of energy accumulation. In this embodiment, the accumulation completion detection means includes a winding detection photocoupler U5 (an example of an accumulation completion detection photocoupler) and a winding detection limit switch LS3 (an example of an accumulation completion detection limit switch). The winding detection photocoupler U5 includes a light-emitting element 39 connected between the first power supply terminal T3 and the second power supply terminal T4, and a phototransistor 40 that is optically coupled to the light-emitting element 39 and is turned on by the light emission of the light-emitting element 39. In this embodiment, the light-emitting element 39 includes two light-emitting diodes connected in reverse parallel. 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 completed, it is turned on and short-circuits the terminals of the light-emitting element 39, and when the spring 4 is completed, it is activated and turned off, releasing the short circuit between the terminals of the light-emitting element 39 and causing the light-emitting element 39 to emit light. This causes the winding detection photocoupler U5 to be turned on (the phototransistor 40 is in a conductive state), and the control circuit 50 is notified that the spring 4 has been wound up.

[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 supply terminal T3 and the second power supply terminal T4. A current limiting resistor R3 is further connected in series to the series circuit of these photocouplers U3, U4, and U5. The photocouplers U3, U4, and U5 may be connected in parallel between the first power supply terminal T3 and the second power supply terminal T4.

[0050] On the other hand, a 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 the 100V AC from the AC power supply e to, for example, 24V AC, and a rectifier circuit 56 that rectifies the 24V AC output from the step-down transformer 55 to generate a DC voltage VP1 of 24V DC. The DC voltage VP1 is used as a power source for operating the electromagnetic brake B.

[0051] Furthermore, a second power supply unit PU2 is connected to the first power supply unit PU1. The second power supply unit PU2 includes a DC-DC converter that steps down the DC 24V generated by the first power supply unit PU1 to an operating voltage Vcc of, for example, DC 5V. The operating voltage Vcc is supplied not only to the control circuit 50 but also to the photo transistors 32, 34, 36, 38, 40 of the photocouplers U1 to U5, the light emitting elements 41, 43 of the photo thyristor couplers U6, U7, and the like.

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

[0053] The photo transistors 32, 34, 36, 38, 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 the ground potential via pull-down resistors R11 to R15, respectively. According to the conduction / non-conduction of the photo transistors 32, 34, 36, 38, 40 (that is, according to the on / off of the photocouplers U1 to U5), H-level / L-level signals are input to the input ports P1 to P5. The H level (high level) is the operating voltage Vcc, and the L level (low level) is the ground potential.

[0054] On one hand, the light-emitting elements 41 and 43 of the photo-triac couplers U6 and U7 are respectively connected to the output ports P11 and P12 of the control circuit 50. Operating voltage Vcc is applied to each of the light-emitting elements 41 and 43 via current-limiting resistors R16 and R17. By controlling the potentials of the output ports P11 and P12 by the control circuit 50, the on / off states of the light-emitting elements 41 and 43 (i.e., the on / off states of the photo-triac couplers U6 and U7) are controlled. Also, 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 to 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 to control the electromagnetic brake B to a braking state or a non-braking state. During a power outage, since the power supply to the electromagnetic brake B is cut off, the electromagnetic brake B becomes a non-braking state. Note that since the electromagnetic brake B is not frequently turned on / off, the problem of electromagnetic noise associated with on / off is small. Therefore, the power supply / shutdown to the electromagnetic brake B may be performed by a relay, and the excitation / demagnetization of the coil of the relay may be controlled by the power transistor Q3.

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

[0056] [Control Logic] FIG. 4 shows a logic circuit for explaining a control example by the control circuit 50. The control logic by this logic circuit is typically realized by a microcomputer included in the control circuit 50 executing software. Of course, it goes without saying that the hardware (electronic circuit) constituting this logic circuit may be provided in the control circuit 50.

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

[0058] The first input of the NAND gate 81 is connected to the input port P1, and is given an open - command detection signal output by the open - command detection photocoupler U1. The open - command detection signal is at the H level if an open command is given, and at the L level if no open command is given. The second input of the NAND gate 81 is connected to the input port P3, and is given the all - open detection signal output by the all - open detection photocoupler U3 after logical inversion. The all - open detection signal is at the L level when all - open is not detected, and at the H level when all - open is detected. Therefore, the second input of the NAND gate 81 is at the H level when all - open is not detected, and at the L level when all - open is detected.

[0059] Therefore, when an open command is detected and all - open is not detected, the output of the NAND gate 81 becomes the L level, the light - emitting element 41 of the opto - triac coupler U6 emits light, and the opto - triac coupler U6 becomes in the on state. Thereby, 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 open direction and the valve body 1 reaches the fully - open position, the all - open detection signal is inverted to the H level, so the output of the NAND gate 81 is inverted to the H level. Then, the light - emitting element 41 of the opto - triac coupler U6 stops emitting light, the opto - triac coupler U6 becomes in the off state, and accordingly, the open semiconductor switch Q1 becomes in the cut - off state, and the electric motor M stops being driven.

[0061] If the opening command is not detected, the opening command detection signal becomes the L level. Therefore, the output of the NAND gate 81 becomes the H level, the photo triac coupler U6 turns off, and thus the opening semiconductor switch Q1 is in the off state, and the electric motor M stops driving.

[0062] The logic circuit in the control circuit 50 includes a NOR gate 82 for driving the light emitting element 43 of the photo triac coupler U7 that drives the closing semiconductor switch Q2. An AND gate 83 is connected to the first input of the NOR gate 82, and a winding-up completion detection signal (L level when the spring winding-up is not completed, H level when the spring winding-up is completed) from the winding-up detection photo coupler U5 is inverted and input to the second input of the NOR gate 82 from the input port P5. The closing command detection signal given from the closing command detection photo coupler U2 to the input port P2 is input to the first input of the AND gate 83. The fully closed detection signal given from the fully closed detection photo coupler U4 to the input port P4 is inverted and input to the second input of the AND gate 83. Therefore, the output of the AND gate 83, that is, the first input of the NOR gate 82, becomes the H level when the closing command is detected and the fully closed state is not detected, and becomes the L level when the closing command is not detected or the fully closed state is detected. The output of the NOR gate 82 is connected to the output port P12 connected to the light emitting element 43 of the photo triac coupler U7.

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

[0064] Also, when the spring winding is not completed, the output of the NOR gate 82 is at the L level. Accordingly, the photo triac coupler U7 is turned on, the closed semiconductor switch Q2 conducts, and the electric motor M rotates in the closed direction. Thereby, the initial operation for spring winding is performed. After the winding of the spring 4 is completed by the initial operation, the on / off of the photo triac 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 the completion of spring winding is not detected, the input to the input port P5 is at the L level, the output port P13 is at the L level, and the power transistor Q3 is in the cutoff state. Therefore, the energization of the electromagnetic brake B is in the stopped state, and the electromagnetic brake B is in the non-braking state. When the completion of spring winding is detected, since the input to the input port P5 becomes the H level, the output port P13 becomes the H level, and the power transistor Q3 conducts. Thereby, the electromagnetic brake B is energized, and the electromagnetic brake B is in the braking state.

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

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

[0068] From this state, when an AC power supply e is connected to the first power supply terminal T3 and the second power supply terminal T4 and power-on is started (including recovery from a power outage), the initial operation is started. Until the completion of the initial operation, the control circuit 50 does not accept the input of the close command detection signal and the open command detection signal to the input ports P1 and P2 as invalid. Since the fully open detection limit switch LS1 is in a conductive state, the fully open detection photocoupler U3 is in an off state, and the fully open detection signal (input port P3) is at the L level indicating a non-detection state of full opening. Since the fully closed detection limit switch LS2 is in an open state, the fully closed detection photocoupler U4 is in an on state, and the fully closed detection signal (input port P4) is at the H level indicating a fully closed detection state. Since the winding-up detection limit switch LS3 is in a conductive state, the winding-up detection photocoupler U5 is in an off state, and the winding-up completion detection signal (input port P5) is at the L level indicating non-detection of winding-up completion. Therefore, the electromagnetic brake B is in a non-braking state. On the other hand, since the phototriac coupler U7 that drives the closed semiconductor switch Q2 is in an on state, the electric motor M rotates in the closed direction. Thereby, the initial operation for spring winding-up (see Fig. 2A) is performed. When the spring winding-up is completed, the winding-up detection limit switch LS3 becomes open, and the winding-up detection photocoupler U5 turns on, so that the winding-up completion detection signal (input port P5) becomes the H level indicating the completion of spring winding-up. Thereby, the electromagnetic brake B becomes in a braking state, and the rotation of the electric motor M in the closed direction stops. Thus, the initial operation is completed.

[0069] After that, when an open command is input from the control panel 20, the open command detection photocoupler U1 becomes on, so the open command detection signal (input port P1) becomes the H level indicating open command detection. At this time, since the fully open detection limit switch LS1 is in the conducting state, the fully open detection photocoupler U3 is in the off state, and the fully open detection signal (input port P3) is the L level indicating non-detection of full opening. Therefore, the output of the NAND gate 81 becomes the L level, and the phototriac coupler U6 that drives the open semiconductor switch Q1 becomes on. Thereby, the electric motor M rotates in the open direction. When the input of the open command stops, the output of the NAND gate 81 is inverted to the 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 cut off and the fully open detection photocoupler U3 is turned on. Thereby, since the output of the NAND gate 81 is inverted to the H level, the electric motor M stops.

[0070] When driving from the fully closed position in the open direction, the fully closed detection limit switch LS2 changes from the cut-off state to the conducting state, so the fully closed detection photocoupler U4 becomes the off state, and the fully closed detection signal (input port P4) becomes the L level indicating non-detection of full closing. In this state, when a close command is input, the close command detection photocoupler U2 becomes on, and the close command detection signal (input port P2) becomes the H level indicating close command detection. Then, since the output of the AND gate 83 becomes the H level, the phototriac coupler U7 that drives the close semiconductor switch Q2 is turned on by the NOR gate 82. Thereby, the electric motor M rotates in the close direction. When the input of the close command stops, the output of the AND gate 83 is inverted to the L level, and accordingly, the output of the NOR gate 82 is inverted to the H level, so the electric motor M stops. If the input of the close command continues until the valve body 1 reaches the fully closed position, the fully closed detection limit switch LS2 is cut off and the fully closed detection photocoupler U4 is turned on, so the fully closed detection signal (input port P4) becomes the H level indicating full closing detection. Thereby, the output of the AND gate 83 is inverted to the L level, and accordingly, the output of the NOR gate 82 is inverted to the H level, so the electric motor M stops.

[0071] When the power supply from the AC power supply e is interrupted due to a power outage or the like, the energization to the electromagnetic brake B stops and it becomes a non-braking state. As a result, the energy stored in the spring 4 is released, and an emergency shut-off operation is performed to move the valve body 1 to the fully closed position by this energy.

[0072] [Summary of the Embodiment] As described above, the electric valve 100 of this embodiment includes a valve body 1 that opens and closes a flow path, an electric motor M for operating the valve body 1, and a control circuit 50 that controls the electric motor M. The electric motor M has an open terminal ma, a closed terminal mb, and a common terminal mc. When energized between the open terminal ma and the common terminal mc, it rotates in the open direction to drive the valve body 1 in the open direction, and when energized between the closed terminal mb and the common terminal mc, it rotates in the closed direction to drive the valve body 1 in the closed direction. An open command from the outside that commands the operation of the valve body 1 in the open direction is input to the open command terminal T1, and the input of this open command is detected by the open command detection element (U1). Also, a close command from the outside that commands the operation of the valve body 1 in the closed direction is input to the close command terminal T2, and this close command is detected by the close command detection element (U2). The AC power supply e, which is an external power supply, 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 supply terminal T3 by a common power supply line Pc. And the open terminal ma of the electric motor M is connected to the second power supply terminal T4 via an open power supply line Pa, and its closed terminal mb is connected to the second power supply terminal T4 by starting 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. When the open command detection element (U1) detects the input of the open command, the control circuit 50 turns on the open semiconductor switch Q1, and when the close command detection element (U2) detects the input of the close command, the control circuit 50 turns on the closed semiconductor switch Q2.

[0073] According to this configuration, open commands and close commands from the outside are detected outside the power supply path to the electric motor M, and the conduction / blocking of the open semiconductor switch Q1 and the close semiconductor switch Q2 is controlled by the control circuit 50 in response to the detection of the open command and the close command. Thereby, appropriate energization to the electric motor M can be performed according to the open command and the close command, and the valve body 1 can be opened and closed.

[0074] Since the open semiconductor switch Q1 and the close semiconductor switch Q2 do not have mechanical contacts, there is no problem of high cost caused by using a mechanical relay with a large contact capacity, and there is no need for maintenance according to the durability life (number of operations) of the contacts. Thereby, an electric valve 100 advantageous for cost reduction or reduction of maintenance work can be provided. In addition, compared with using a relay having mechanical contacts, opening and closing by a semiconductor switch can reduce electromagnetic noise, and thereby, the influence on the operation of an electronic circuit arranged near the electric valve 100 can be reduced.

[0075] Also, the command signal generator 21 of the control panel 20 is connected to the open command detection element (U1) and the close command detection element (U2), and is arranged outside the power supply path to the electric motor M, so it does not open and close a large current. Therefore, the generation of electromagnetic noise in the command signal generator 21 can also be suppressed. Accordingly, the influence on the operation of an electronic circuit arranged near the control panel 20 can also be reduced. Also, even when the command signal generator 21 has mechanical contacts, it does not require a large contact capacity, so cost reduction can be achieved. Also, since it does not require opening and closing of a large current, the number of operations until the end of its life increases, and accordingly, the labor of maintenance can be reduced.

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

[0077] Also, in the above-described embodiment, the electric valve 100 further includes an all-open detection means (U3, LS1) for detecting that the valve body 1 has reached the fully open position. Then, if the opening command detection element (U1) detects the input of the opening command and the all-open detection means (U3, LS1) does not detect all-open, the control circuit 50 turns on the opening semiconductor switch Q1; otherwise, it turns off the opening semiconductor switch Q1. Thereby, 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. Also, the opening and closing of the opening power supply wire Pa according to whether the valve body 1 is in the fully open position or not is also performed by the opening semiconductor switch Q1, and the relay having mechanical contacts is not involved.

[0078] In the above-described embodiment, the fully open detection means includes a fully open detection photocoupler U3 including a light emitting element 35 connected between a first power supply terminal T3 and a second power supply terminal T4, and a fully open detection limit switch LS1 that operates when the valve body 1 reaches the fully open position and reverses the on / off state of the light emitting element 35 of the fully open detection photocoupler U3. With this configuration, it is possible to detect whether the valve body 1 is in the fully open position and notify the control circuit 50 while electrically insulating the external power supply (AC power supply e) and the control circuit 50. Since the fully open detection limit switch LS1 does not open and close the opening power supply wire Pa, substantially no electromagnetic noise is generated due to the operation of the fully open detection limit switch LS1. In the above-described embodiment, the fully open detection limit switch LS1 shorts the terminals of the light emitting element 35 to turn off (extinguish) the light emitting element 35 if the valve body 1 is not in the fully open position, and releases 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 an example, and it is also possible to reverse the logic and design such that the light emitting element 35 is turned on in the fully open position and turned off outside the fully open position.

[0079] Also, in the above-described embodiment, the electric valve 100 further includes fully closed detection means (U4, LS2) for detecting that the valve body 1 has reached the fully closed position. And when the close command detection element (U2) detects the input of a close command and the fully closed detection means (U4, LS2) has not detected full closure, the control circuit 50 turns on the close semiconductor switch Q2, otherwise it turns off the close semiconductor switch Q2. Thereby, 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. Also, the opening and closing of the closing power supply wire Pb according to whether the valve body 1 is in the fully closed position is also performed by the close semiconductor switch Q2, and a relay having mechanical contacts is not involved.

[0080] In the above-described embodiment, the fully-closed detection means includes a fully-closed detection photocoupler U4 including a light-emitting element 37 connected between the first power supply terminal T3 and the second power supply terminal T4, and a fully-closed detection limit switch LS2 that operates when the valve body 1 reaches the fully-closed position and reverses the on / off state of the light-emitting element 37 of the fully-closed detection photocoupler U4. With this configuration, it is possible to detect whether the valve body 1 is in the fully-closed position and notify the control circuit 50 while electrically insulating the external power supply (alternating current power supply e) from the control circuit 50. Since the fully-closed detection limit switch LS2 does not open and close the closed power supply line Pb, substantially no electromagnetic noise is generated due to the operation of the fully-closed detection limit switch LS2. In the above-described embodiment, the fully-closed detection limit switch LS2 shorts the terminals of the light-emitting element 37 to turn off (extinguish) the light-emitting element 37 if the valve body 1 is not in the fully-closed position, and releases 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 an example, and it is also possible to reverse the logic and design such that the light-emitting element 37 is turned on in the fully-closed position and turned off outside the fully-closed position.

[0081] Also, in the above-described embodiment, the electric valve 100 includes a spring 4 that accumulates energy for an emergency operation, and an accumulation completion detection means (U5, LS3) that detects the completion of energy accumulation in the spring 4. And the control circuit 50 executes an initial operation to drive the electric motor M to accumulate energy in the spring 4 until the accumulation completion detection means (U5, LS3) detects the completion of energy accumulation in the spring 4 when the first power supply terminal T3 and the second power supply terminal T4 are connected to an external power supply (alternating current power supply e) and the accumulation completion detection means (U5, LS3) has not detected the completion of energy accumulation in the spring 4. In the above-described embodiment, the emergency operation is an emergency closing that closes the valve body 1 by the energy of the spring 4, and the initial operation is an operation of turning on the closed semiconductor switch Q2 to rotate the electric motor M in the closing direction. However, this is just an example, and the emergency operation may be an emergency opening that opens the valve body 1 by the energy of the spring 4. In this case, the initial operation may be an operation of turning on the open semiconductor switch Q1 to rotate the electric motor M in the opening direction.

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

[0083] In the above embodiment, the storage completion detection means includes a winding detection photocoupler U5 (storage completion detection photocoupler) including a light emitting element 39 connected between the first power supply terminal T3 and the second power supply terminal T4, and a winding detection limit switch LS3 (storage completion detection limit switch) that operates when the energy storage of the spring 4 is completed and reverses the on / off of the light emitting element 39 of the winding detection photocoupler U5 (storage completion detection photocoupler). With this configuration, it is possible to detect the incompletion / completion of the energy storage of the spring 4 and notify the control circuit 50 while electrically insulating the external power supply (alternating current power supply e) and the control circuit 50. In the above embodiment, the winding detection limit switch LS3 shorts the terminals of the light emitting element 39 to turn off (extinguish) the light emitting element 39 if the spring winding (energy storage) is incomplete, and releases 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 completed. However, this is just an example, and it is also possible to design it to reverse the logic, turn on the light emitting element 39 when the spring winding (energy storage) is completed, and turn off the light emitting element 39 when the spring winding (energy storage) is incomplete.

[0084] Also, in the above embodiment, the electric motor M is an alternating current motor. And the electric valve 100 includes a zero-cross type open drive circuit 51 and a zero-cross type closed drive circuit 52 that are controlled by the control circuit 50 to perform zero-cross operation on the open semiconductor switch Q1 and the closed semiconductor switch Q2 respectively. With this configuration, the open semiconductor switch Q1 and the closed semiconductor switch Q2 turn on / off (zero-cross operation) near the zero voltage of the alternating current voltage. Thereby, the generation of electromagnetic noise can be further reduced.

[0085] Also, in the above-described embodiment, the zero-cross type open drive circuit 51 includes a light-emitting element 41 that is turned on / off by the control circuit 50, and a zero-cross type photo triac 42 that is optically coupled to the light-emitting element 41, and is configured to drive the open semiconductor switch Q1 by the photo triac 42. Similarly, the zero-cross type close drive circuit 52 includes a light-emitting element 43 that is turned on / off by the control circuit 50, and a zero-cross type photo triac 44 that is optically coupled to the light-emitting element 43, and is configured to drive the close semiconductor switch Q2 by the photo triac 44. With this configuration, power supply to the electric motor M can be controlled while electrically insulating the power supply lines Pa, Pb and the control circuit 50.

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

[0087] For example, in the above-described embodiment, the fully open detection means (U3, LS1) detects full opening and turns off the open semiconductor switch Q1, but the limit switch LS1 may be interposed in the open power supply line Pa, and when the valve body 1 reaches the fully open position, the limit switch LS1 cuts off the open power supply line Pa. Similarly, in the above-described embodiment, the fully closed detection means (U4, LS2) detects full closing and turns off the close semiconductor switch Q2, but the limit switch LS2 may be interposed in the close power supply line Pb, and when the valve body 1 reaches the fully closed position, the limit switch LS2 cuts off the close power supply line Pb. In these configurations, electromagnetic noise is generated when the limit switches LS1, LS2 operate at the fully open position and / or the fully closed position. However, for example, in applications where the opening degree of the valve body 1 is adjusted to an intermediate opening degree between fully closed and fully open, the number of operations of the limit switches LS1, LS2 is small, so it may not be a substantial problem.

[0088] In the above-described embodiment, the completion of the winding-up 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 limit switch LS3 (or a relay that operates in response to the operation of the limit switch LS3) may be interposed in the power supply line from the first power supply unit PU1 to the electromagnetic brake B. During the normal operation period after the initial operation is completed, the energization of the electromagnetic brake B is not turned on / off, so the generation of electromagnetic noise associated with the on / off of the electromagnetic brake B may not be a substantial problem in some cases.

[0089] Also, in the above-described embodiment, the electromagnetic brake B is designed to be in an unbrake state and release the energy of the spring 4 when the external power supply is cut off, but this is just an example. For example, it is also possible to design the electromagnetic brake B to be controlled based on the detection signal of a sensor such as a seismic sensor. In order to maintain the operation in response to the sensor even during a power failure, it is sufficient to provide a built-in power supply that maintains the power supply to the control circuit 50 and the electromagnetic brake B even when the external power supply is interrupted. The built-in power supply is typically a secondary battery or an electric double layer capacitor. When such a built-in power supply is provided, it is also possible to use an electromagnetic brake B of the non-excitation operation type that becomes in a brake state when not excited.

[0090] Also, in the above-described embodiment, a configuration including the spring 4 for emergency operation and the electromagnetic brake B for operating it is shown, but the present invention may also be applied to an electric valve that does not include them.

[0091] In addition, various design changes can be made within the scope of the matters described in the claims.

Explanation of Reference Numerals

[0092] 1: Valve body 4: Spring 20: Control panel 21: Command signal generator 31, 33, 35, 37, 39: Light-emitting element 32, 34, 36, 38, 40: Phototransistor 41, 43: Light-emitting element 42, 44: Phototriac 50: Control circuit 51: Zero-cross type open drive circuit 52: Zero-cross type close 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: Hoisting detection limit switch M: Electric motor Pa: Open power supply wire Pb: Close power supply wire Pc: Common power supply wire Q1: Open semiconductor switch Q2: Close semiconductor switch Q3: Power transistor T1: Open command terminal T2: Close command terminal T3: First power supply terminal T4: Second power supply terminal U1: Open command detection photocoupler U2: Close command detection photocoupler U3: Fully open detection photocoupler U4: Fully closed detection photocoupler U5: Hoisting detection photocoupler U6: Phototriac coupler U7: Phototriac coupler e: AC power supply ma: Open terminal mb: Close terminal mc: Common terminal

Claims

1. A valve body for opening and closing a flow path, generates a driving force for operating the valve body, has an open terminal, a closed terminal, and a common terminal, and drives the valve body in the open direction when energized between the open terminal and the common terminal, and drives the valve body in the closed direction when energized between the closed terminal and the common terminal. An electric motor, An open command terminal to which an open command for commanding the operation of the valve body in the open direction is input from the outside, A close command terminal to which a close command for commanding the operation of the valve body in the close direction is input from the outside, A first power supply terminal and a second power supply 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 close command detection element for detecting the input of a close command to the close command terminal, A common power supply line connecting the common terminal to the first power supply terminal, An open power supply line connecting the open terminal to the second power supply terminal, A close 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 close semiconductor switch interposed in the close power supply line, A control circuit that conducts the open semiconductor switch when the open command detection element detects the input of an open command, and conducts the close semiconductor switch when the close command detection element detects the input of a close command, An electric valve including

2. 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 supply terminal, The close command detection element includes a close command detection photocoupler including a light emitting element connected between the close command terminal and the first power supply terminal. The electric valve according to claim 1.

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

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

5. Further includes a fully closed detection means for detecting that the valve body has reached the fully closed position, If the control circuit detects an input of a closing command by the closing command detection element and the fully closed detection means does not detect full closing, the control circuit turns on the closing semiconductor switch; otherwise, the control circuit turns off the closing semiconductor switch. The motor-operated valve according to claim 1.

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

7. A spring that stores energy for an emergency operation, and further includes storage completion detection means for detecting completion of energy storage of the spring, When the first power supply terminal and the second power supply terminal are connected to an external power supply and the storage completion detection means does not detect completion of energy storage of the spring, the control circuit drives the electric motor by conducting one of the opening semiconductor switch and the closing semiconductor switch determined in advance until the storage completion detection means detects completion of energy storage of the spring, thereby performing an initial operation for storing energy in the spring. The motor-operated valve according to claim 1.

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

9. The electric motor is an alternating current motor, and further includes a zero-crossing type opening drive circuit and a zero-crossing type closing drive circuit that are controlled by the control circuit and perform zero-crossing operations on the opening semiconductor switch and the closing semiconductor switch, respectively. The motor-operated valve according to any one of claims 1 to 8.

10. The zero-crossing type opening drive circuit includes a light-emitting element that is turned on / off by the control circuit, and a zero-crossing type phototriac that is optically coupled to the light-emitting element, and is configured to drive the opening semiconductor switch by the phototriac. The zero-cross type closed drive circuit according to claim 9 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.

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