JP3398575B2 - Electric actuator - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric actuator in which a valve for controlling a flow rate, a damper for controlling an air volume, and the like are used as an operating end, and a return spring is provided on a drive shaft of the operating end.

[0002]

2. Description of the Related Art Conventionally, as this type of electric actuator, a spring return type actuator having a valve or a damper at its operating end has been used. In this spring return type actuator, by transmitting the rotational force of the drive motor to the operating end via the reduction mechanism,
The torque is increased to open and close the operating end, that is, the valve or damper. A return spring is provided on the drive shaft of the valve and damper, and when the main power to the electric actuator is cut off due to a power failure or the like, the force of the return spring (to prevent adverse effects on other devices) The operating end is forcibly closed or fully opened by the return force (return torque).

[Prior Art 1] FIG. 9 shows an example of a conventional electric actuator for proportional control. FIG. 1 shows the configuration of the main parts of this electric actuator. 1 is a drive shaft of an operating end (valve), 2 is a return spring attached to the drive shaft 1, 3 is a drive motor, 4 is a reduction gear train, and 5 is a reduction gear train. Is a clutch. In this electric actuator, a drive motor 3 having a holding torque is used.
Power is supplied to the drive motor 3 via an operation changeover switch (not shown). Further, the clutch 5 is constantly supplied with electric power to be in clutch engagement, and the output shaft of the drive motor 3 is constantly rotationally coupled to the drive shaft 1 via the reduction gear train 4.

When power is supplied to the drive motor 3 with the operation changeover switch open, the drive motor 3 rotates in the normal direction and the drive torque of the drive motor 3 is increased by the clutch 5 and the reduction gear train 4.
Is transmitted to the drive shaft 1 via the return spring 2
The drive shaft 1 moves in the opening direction against the restoring force of. When the operation changeover switch is turned off (neutral), the drive shaft 1 holds the current operation position by the holding torque of the drive motor 3. When power is supplied to the drive motor 3 with the operation selector switch closed, the drive motor 3 reversely rotates,
The drive torque of the drive motor 3 is transmitted to the drive shaft 1 via the clutch 5 and the reduction gear train 4, and the drive shaft 1 operates in the closing direction.

When the main power supply to the electric actuator is cut off due to a power failure or the like, the power supply to the clutch 5 is also cut off. Therefore, the clutch 5 is disengaged, the torque of the drive motor 3 is not transmitted to the drive shaft 1, and the return force of the return spring 2 causes the drive shaft 1 to move in the closing direction, forcibly closing the valve. It is said that

[Conventional Example 2] FIG. 10 shows another example of a conventional electric actuator for proportional control. The figure shows the configuration of the main parts of this electric actuator, and the same symbols as in FIG. 9 indicate the same components. In this electric actuator, a drive motor 3'having no holding torque is used, and a brake device 6 is used in place of the clutch 5.

[0007] Operation 'when supplying power to the drive motor 3' the switch drive motor 3 as an open side and forward, driving the driving torque of the drive motor 3 'is via the reduction gear train 4 shaft 1 Is transmitted to the drive shaft 1, and the drive shaft 1 operates in the opening direction against the return force of the return spring 2. When the operation changeover switch is turned off (neutral), the supply of power to the brake device 6 is started, the holding torque by friction braking is generated by the operation of the brake device 6, and the drive shaft 1 holds the current operating position. . When power is supplied to the drive motor 3'with the operation changeover switch closed, the power supply to the brake device 6 is cut off, the brake device 6 is deactivated, and the holding torque due to friction braking disappears.
As a result, the drive motor 3'reverses, the drive torque of the drive motor 3'is transmitted to the drive shaft 1 via the reduction gear train 4, and the drive shaft 1 operates in the closing direction.

When the main power supply to the electric actuator is cut off due to a power failure or the like, the power supply to the brake device 6 is also cut off. For this reason, the brake device 6 does not operate, and the holding torque due to frictional braking does not occur. Therefore, the return force of the return spring 2 causes the drive shaft 1 to operate in the closing direction, and the valve is forcibly closed. .

[0009]

However, according to such a conventional electric actuator, mechanical components such as the clutch 5 and the brake device 6 that cause friction are required, and deterioration due to wear is likely to occur, resulting in low reliability. There was a problem. In addition, heat generation due to friction in the clutch 5 and the brake device 6 also causes deterioration earlier and reduces reliability. In addition, the number of parts increases, and it is not possible to promote size reduction, weight reduction, and cost reduction.

The present invention has been made to solve the above problems, and an object of the present invention is to use an operating end at an arbitrary operating position without using mechanical parts such as a clutch and a brake device that cause friction. It is an object of the present invention to provide an electric actuator that can hold the device, improve reliability, and reduce size, weight, and cost.

[0011]

In order to achieve such an object, a first invention (an invention according to claim 1) is a drive shaft provided with a return spring, and a reduction gear train on the drive shaft. an output shaft and a rotation combined drive motor and the auxiliary motor through a drive motor and the auxiliary
It is equipped with a control circuit that controls the operation of the auxiliary motor , and the detected angle is more than the target angle to the drive motor in the control circuit.
If small, drive motor and auxiliary motor in normal
Direction, and the detected angle is more than the target angle to the drive motor
Is larger, stop the drive of the auxiliary motor and start
Drive the drive motor in the reverse direction to target the drive motor.
When the angle matches the detected angle, drive the auxiliary motor
A circuit is provided to hold the operating position of the drive shaft at the current position by stopping the motor and applying a brake current to the drive motor to generate a torque that balances the return force of the return spring. is there. According to the present invention, when the detected angle is smaller than the target angle to the drive motor, the drive motor is
Motor and auxiliary motor are driven in the forward direction,
The operation position moves in the opening direction, for example. To drive motor
If the detected angle is larger than the target angle, the drive
Only the motor is driven in the reverse direction, and the operating position of the drive shaft is
For example, it operates in the closing direction. The target angle to the drive motor and
When the detected angles match, a torque (TH) matching the return force (Tsp) of the return spring is generated in the drive motor, and the operating position of the drive shaft is held at the current position. .

[0012]

[0013]

[0014]

The second invention (the invention according to claim 2) is the control
If the detected angle in the circuit is smaller than the target angle to the drive motor, drive the drive motor and auxiliary motor in the forward rotation direction, and the detected angle is larger than the target angle to the drive motor. In this case, the drive motor and auxiliary motor are driven in the reverse direction, and when the target angle to the drive motor and the detected angle match, a brake current is sent to the drive motor and auxiliary motor to restore the return spring. A circuit is provided which generates a torque that balances the force and holds the operating position of the drive shaft at the current position. According to the present invention, when the detected angle is smaller than the target angle to the drive motor, the drive motor and the auxiliary motor are driven in the forward rotation direction, and the operation position of the drive shaft is moved in the opening direction, for example. Operate. When the detected angle is larger than the target angle to the drive motor, the drive motor and the auxiliary motor are driven in the reverse rotation direction, and the operation position of the drive shaft moves in the closing direction, for example. When the target angle to the drive motor matches the detected angle, a torque (TH1 + TH2) that balances the return force (Tsp) of the return spring is generated in the drive motor and the auxiliary motor, and the operation position of the drive shaft is generated. Is held at the current position.

The third invention (the invention according to claim 3) is a control system.
If the detected angle in the circuit is smaller than the target angle to the drive motor, drive the drive motor and auxiliary motor in the forward rotation direction, and the detected angle is larger than the target angle to the drive motor. In this case, stop the driving of the auxiliary motor and then drive the driving motor in the reverse direction, and if the target angle to the driving motor and the detected angle match, apply the braking current to the driving motor and the auxiliary motor. A circuit is provided to generate a torque that balances the return force of the return spring and hold the operating position of the drive shaft at the current position. According to the present invention, when the detected angle is smaller than the target angle to the drive motor, the drive motor and the auxiliary motor are driven in the forward rotation direction, and the operation position of the drive shaft is moved in the opening direction, for example. Operate. When the detected angle is larger than the target angle to the drive motor, only the drive motor is driven in the reverse direction, and the operation position of the drive shaft moves in the closing direction, for example. When the target angle to the drive motor and the detected angle match, a torque that balances the return force (Tsp) of the return spring is generated in the drive motor and the auxiliary motor (TH1 + TH2), and the operating position of the drive shaft is generated. Is held at the current position.

A fourth invention (an invention according to claim 4) is a control system.
If the detected angle in the circuit is smaller than the target angle to the drive motor, drive the drive motor and auxiliary motor in the forward rotation direction, and the detected angle is larger than the target angle to the drive motor. In this case, drive the drive motor and auxiliary motor in the reverse direction, and if the target angle to the drive motor matches the detected angle, stop the drive of the auxiliary motor and apply the brake current to the drive motor. A circuit is provided to generate a torque that balances the return force of the return spring and hold the operating position of the drive shaft at the current position. According to the present invention, when the detected angle is smaller than the target angle to the drive motor, the drive motor and the auxiliary motor are driven in the forward rotation direction, and the operation position of the drive shaft is moved in the opening direction, for example. Operate. When the detected angle is larger than the target angle to the drive motor, the drive motor and the auxiliary motor are driven in the reverse rotation direction, and the operation position of the drive shaft moves in the closing direction, for example. When the target angle to the drive motor and the detected angle match, a torque (TH) that balances the return force (Tsp) of the return spring is generated in the drive motor, and the operation position of the drive shaft becomes the current position. Retained.

[0018]

[ Reference example ]

FIG. 2 is a diagram showing a main part configuration of a reference example of an electric actuator for proportional control. In this electric actuator, as in the conventional electric actuator shown in FIG. 10, a driving motor 3'having no holding torque is used. Further, the brake device 6 shown in FIG. 10 is omitted, and the control circuit 7 has a function in place of the brake device 6. In this reference example , a 4-phase VR type stepping motor is used as the driving motor 3 '.

FIG. 1 is a block diagram showing the internal structure of the control circuit 7. The control circuit 7 includes an arithmetic circuit 7-1, a pulse distribution circuit 7-2, a brake circuit 7-3, a motor drive circuit 7
-4 and an output angle detection circuit 7-5.

The output angle detection circuit 7-5 detects the current angle of the drive motor 3 '. The arithmetic circuit 7-1 compares the input signal from the outside (target angle to the drive motor 3 ') with the detected angle from the output angle detection circuit 7-5 and generates a command signal according to the comparison result. To do.

Here, if the detected angle is smaller than the target angle to the drive motor 3 ', the arithmetic circuit 7-1 sends a normal rotation command to the pulse distribution circuit 7-2. In response to this normal rotation command, the pulse distribution circuit 7-2 is changed to (a) in FIG.
Drive pulse train φ1 in the forward direction as shown in FIG.
φ4 is created and given to the drive motor 3 ′ through the motor drive circuit 7-4. Upon receiving the drive pulse train in the normal rotation direction, the drive motor 3 ′ rotates in the normal direction, and the drive shaft 1 operates in the opening direction.

The arithmetic circuit 7-1 sends a reverse rotation command to the pulse distribution circuit 7-2 when the detected angle is larger than the target angle to the drive motor 3 '. In response to this reverse rotation command,
The pulse distribution circuit 7-2 includes (a) to (d) of FIG.
Drive pulse trains .phi.1 to .phi.4 in the reverse direction as shown in FIG. 4 are created and given to the drive motor 3'through the motor drive circuit 7-4. Upon receiving the drive pulse train in the reverse direction, the drive motor 3'reverses and the drive shaft 1 operates in the closing direction.

When the target angle to the drive motor 3'is coincident with the detected angle, the arithmetic circuit 7-1 detects the brake circuit 7 '.
Send a brake command (position hold command) to -3. In response to this brake command, the brake circuit 7-3 is changed to the one shown in FIG.
(A) to (d) of the brake pulse train (φ
1, φ4 is “H”, φ2 and φ3 are “L” pulse trains), and the drive motor 3 ′ is supplied via the motor drive circuit 7-4.
Give to. Upon receiving this brake pulse train, a brake current flows through the drive motor 3 ', and the return spring 2
A torque T1 = TH (holding torque) that balances the restoring force Tsp of the drive shaft 1 is generated, and the drive shaft 1 holds the current operating position.

When the main power supply to the electric actuator is cut off due to a power failure or the like, no torque is generated in the drive motor 3 ', so that the return force Tsp of the return spring 2 causes the drive shaft 1 to move in the closing direction. However, it is forcibly closed.

According to the electric actuator of this reference example , a braking current is passed through the drive motor 3'to generate the holding torque TH, so that mechanical parts that cause friction such as a clutch and a brake device are not required, and wear is eliminated. Degradation due to heat generation is eliminated and reliability is improved. Further, since mechanical parts such as a clutch and a brake device are not used, it is possible to realize size reduction, weight reduction and cost reduction.

[ Embodiment 1: First Invention ] FIG. 4 is a diagram showing a main configuration of a first embodiment of an electric actuator for proportional control according to the present invention. In this electric actuator, as in the electric actuator shown in FIG. 10, a driving motor 3'having no holding torque is used. Also, the brake device 6 is omitted,
The control circuit 8 has a function replacing the brake device 6. Further, an auxiliary motor 9 is provided in addition to the drive motor 3 ', and the output shaft of the auxiliary motor 9 is connected to the reduction gear train 4
It is rotationally coupled to the drive shaft 1 via. In this embodiment, a four-phase VR type stepping motor is used as the driving motor 3'and a DC motor that produces a back electromotive force is used as the auxiliary motor 9.

FIG. 5 is a block diagram showing the internal structure of the control circuit 8. The control circuit 8 includes an arithmetic circuit 8-1, a pulse distribution circuit 8-2, a brake circuit (driving motor position holding brake circuit) 8-3, a driving motor driving circuit 8-4,
Output angle detection circuit 8-5 and auxiliary motor drive circuit 8
It has -6.

The output angle detection circuit 8-5 detects the current angle of the drive motor 3 '. The arithmetic circuit 8-1 compares the input signal from the outside (target angle to the drive motor 3 ') with the detected angle from the output angle detection circuit 8-5, and generates a command signal according to the comparison result. To do.

Here, when the detected angle is smaller than the target angle to the drive motor 3 ', the arithmetic circuit 8-1 has a pulse distribution circuit 8-2 and an auxiliary motor drive circuit 8-6.
Send forward rotation command to. In response to this normal rotation command, the pulse distribution circuit 8-2 creates drive pulse trains φ1 to φ4 in the normal rotation direction as shown in (a) to (d) of FIG. -4 to the drive motor 3 '. Upon receiving the drive pulse train in the normal rotation direction, the drive motor 3'rotates normally. In addition, the auxiliary motor drive circuit 8-6
In response to the forward rotation command from the arithmetic circuit 8-1,
Drive current in the forward direction + I as shown in (e) of (a)
To the auxiliary motor 9. Upon receiving the drive current + I in the normal rotation direction, the auxiliary motor 9 rotates in the normal direction. By the normal rotation of the drive motor 3'and the auxiliary motor 9, that is, by adding the auxiliary torque T2 of the auxiliary motor 9 to the drive torque T1 of the drive motor 3 ', the drive shaft 1 operates in the opening direction.

The arithmetic circuit 8-1 sends a reverse rotation command to the pulse distribution circuit 8-2 when the detected angle is larger than the target angle to the drive motor 3 '. In this case, a stop command is sent to the auxiliary motor drive circuit 8-6, and the auxiliary motor 9
The drive current to I is set to I = 0 (see (e) in FIG. 6B). In response to the reverse rotation command from the arithmetic circuit 8-1, the pulse distribution circuit 8-2 forms drive pulse trains φ1 to φ4 in the reverse rotation direction as shown in (a) to (d) of FIG. It is given to the drive motor 3 ′ through the motor drive circuit 8-4. Upon receiving the drive pulse train in the reverse direction, the drive motor 3'reverses and the drive torque T1 generated by this
The drive shaft 1 thus moves in the closing direction. At this time, since the drive current to the auxiliary motor 9 is set to I = 0, the auxiliary torque T2 by the auxiliary motor 9 is not generated.

When the target angle to the drive motor 3'is coincident with the detected angle, the arithmetic circuit 8-1 determines the brake circuit 8-1.
Send a brake command to -3. In this case, a stop command is sent to the auxiliary motor drive circuit 8-6, and the drive current to the auxiliary motor 9 is set to I = 0 (see (e) in FIG. 6C). In response to the brake command from the arithmetic circuit 8-1, the brake circuit 8-3 causes the brake pulse train (φ1, φ4 to be “H”, φ4) as shown in (a) to (d) of FIG.
2, φ3 form a pulse train of “L”, and give it to the drive motor 3 ′ via the motor drive circuit 8-4. In response to this brake pulse train, a brake current flows through the drive motor 3 ', a torque T1 = TH (holding torque) that balances the restoring force Tsp of the return spring 2 is generated, and the drive shaft 1 moves to the current opening position. Hold. At this time, since the drive current to the auxiliary motor 9 is set to I = 0, the auxiliary torque T2 by the auxiliary motor 9 is not generated.

In this embodiment, the auxiliary torque T2 of the auxiliary motor 9 is added to the driving torque T1 of the driving motor 3'when the driving shaft 1 is operated in the opening direction against the restoring force Tsp of the return spring 2. Since it is added, the load on the drive motor 3'is reduced, and the drive motor 3'can be downsized. That is, the auxiliary torque T2 that is equivalent to the restoring force Tsp of the return spring 2 is applied to the auxiliary motor 9.
By causing the driving motor 3 ′ to operate, it is not necessary to consider the restoring force Tsp of the return spring 2 so that the driving motor 3 ′ can reduce the load on the driving motor 3 ′. The size can be reduced. Further, in this embodiment, since the auxiliary torque T2 by the auxiliary motor 9 is set to zero when the drive shaft 1 is operated in the closing direction, the speed does not become too high during the operation in the closing direction. Further, in this embodiment, by setting the auxiliary torque T2 by the auxiliary motor 9, it is possible to make the torque of the same degree in both the opening direction and the closing direction of the drive shaft 1, and it is possible to set the torque in the opening direction and the closing direction. The torque can be balanced during operation in the direction. Further, in this case, the return force Tsp of the return spring 2 can be made large within the range of the position holding torque of the drive motor 3 ', and the return operation at the time of power interruption can be made more reliable.

[ Second Embodiment ] In the second embodiment, as shown in FIG. 7, a control circuit 8'is provided.
The arithmetic circuit 8-1, the pulse distribution circuit 8-2, and the first brake circuit (driving motor position holding brake circuit) 8
-3, a drive motor drive circuit 8-4, an output angle detection circuit 8-5, an auxiliary motor drive circuit 8-6, a switching circuit 8-7 and a second brake circuit (return deceleration brake circuit). ) 8-8 is provided.

The switching circuit 8-7 monitors the state of power supply to this electric actuator, and when the power is supplied, the command from the arithmetic circuit 8-1 is sent to the auxiliary motor drive circuit 8-6. send. As a result, in the normal state where the power is supplied, the same operation as the control circuit 8 shown in FIG. 5 is performed.

On the other hand, when the power supply is cut off due to a power failure or the like, the switching circuit 8-7 switches its circuit state and sends a brake signal to the brake circuit 8-8. The brake circuit 8-8 receives the brake signal from the switching circuit 8-7 and short-circuits the power supply terminals of the auxiliary motor 2.

On the other hand, when the power supply is cut off due to a power failure or the like, no torque is generated in the drive motor 3'and the auxiliary motor 9, so that the drive shaft 1 is closed by the return force Tsp of the return spring 2. To work. During the return operation of the drive shaft 1, a counter electromotive force is generated in the auxiliary motor 9, and the torque T2 = TB (brake torque) in the direction opposite to the rotation direction generated thereby causes the drive shaft 1
The operation speed of is suppressed, and the shock at the time of fully closing is softened.

In this embodiment, the switching circuit 8-
Although the power signal terminals of the auxiliary motor 2 are simply short-circuited by the brake signal from 7, the brake torque TB can be adjusted even with the same motor by changing the resistance of the short line. That is, if the variable resistance is inserted in the short line, the brake torque TB becomes maximum when the value of the variable resistance is zero, and the brake torque TB can be adjusted by changing the resistance value.

Further, in the first and second embodiments described above, as a variation, as shown in (a) to (e) of FIGS. 6A, 6B, and 6C, the opening direction of the drive shaft 1 is changed. During operation, the drive motor 3'and the auxiliary motor 9 are driven in the forward direction to generate the drive torque T1 and the auxiliary torque T2, and when the drive shaft 1 is in the closing direction, the auxiliary motor 9 is stopped and driven. The driving motor 3'is driven in the reverse direction to generate the driving torque T1, and when the position of the driving shaft 1 is held, the driving of the auxiliary motor 9 is stopped and a braking current is supplied to the driving motor 3'to hold the holding torque TH. Although it is generated ( first invention ), as a variation, FIG.
(A), (b) and (c) (a) to (d) and (f)
As shown in FIG. 3, when the drive shaft 1 is in the opening direction, the drive motor 3'and the auxiliary motor 9 are driven in the forward direction to generate the drive torque T1 and the auxiliary torque T2.
Drive motor 3'and auxiliary motor 9 are driven in the reverse rotation direction to generate drive torque T1 and auxiliary torque T2, and drive motor 3'and auxiliary motor 9 are held when the position of drive shaft 1 is maintained. A holding current T1 = TH1 and T2 = TH2 may be generated by applying a brake current to the valve ( second invention ).

As a variation, FIG.
(A), (b), (c) (a) to (d) and (g)
As shown in FIG. 3, when the drive shaft 1 is in the opening direction, the drive motor 3'and the auxiliary motor 9 are driven in the forward direction to generate the drive torque T1 and the auxiliary torque T2.
Driving operation of the auxiliary motor 9 is stopped and the driving motor 3'is driven in the reverse direction to drive torque T1.
When the position of the drive shaft 1 is maintained, a braking current may be applied to the drive motor 3'and the auxiliary motor 9 to generate the holding torques TH1 and TH2 ( third invention ).

As a variation, FIG.
(A), (b) and (c) (a) to (d) and (h)
As shown in FIG. 3, when the drive shaft 1 is in the opening direction, the drive motor 3'and the auxiliary motor 9 are driven in the forward direction to generate the drive torque T1 and the auxiliary torque T2.
Drive motor 3'and auxiliary motor 9 are driven in the reverse direction during the closing direction operation to generate drive torque T1 and auxiliary torque T2. When the position of drive shaft 1 is maintained, the drive of auxiliary motor 9 is stopped. A holding current TH1 may be generated by applying a brake current to the drive motor 3 '( fourth invention ).

In the case of the variation, when the operating position of the drive shaft 1 is held, the auxiliary torque T2 by the auxiliary motor 9 is applied, so that the load on the drive motor 3'is reduced. Further, when the drive shaft 1 is operated in the closing direction, since the auxiliary torque T2 by the auxiliary motor 9 is applied, the operation can be secured even when the fluid reaction force is strong. With a variation, when holding the operating position of the drive shaft 1,
Since the auxiliary torque T2 is applied by the auxiliary motor 9, the load on the drive motor 3'is reduced. Also, drive shaft 1
Since the auxiliary torque T2 by the auxiliary motor 9 is set to zero when the is operated in the closing direction, the closing direction operation is not too fast. In the case of the variation, when the drive shaft 1 is operated in the closing direction, the auxiliary torque T2 is applied by the auxiliary motor 9, so that the operation can be secured even when the fluid reaction force is strong.

FIG. 8 shows a case 1 when the drive shaft 1 is in the opening direction, a case 2 when the position of the drive shaft 1 is held, a case 3 when the drive shaft 1 is in the closing direction, and a case 4 when the drive shaft 1 is in the non-energized return state.
Variations 1 to 4 in which the generated torques T1 and T2 of the drive motor 3'and the auxiliary motor 9 are
And the relationship of the overall torque T is shown. In addition, in FIG.
The torque in the forward rotation direction is +, and the torque in the reverse rotation direction is −, and the reference numerals are given.

Although a DC motor is used as the auxiliary motor 9 in the above-described embodiment, a DC motor type motor (DC servo motor) is used as a back electromotive force generation type motor.
Besides, it is possible to use a synchronous machine type motor (stepping motor, brushless motor) or the like.

[0044]

According to apparent the present invention since it has been described above, when the detection angle that is actually detected and the target angle of the drive motor is matched, for driving dynamic motor or drive motor and the auxiliary A brake current flows through the motor, a torque (TH) that balances the return force (Tsp) of the return spring is generated, and the operating position of the drive shaft is held at the current position, causing friction such as in the clutch and brake device. It becomes possible to secure a holding torque at an arbitrary operation position without using mechanical parts, improve reliability, and realize size reduction, weight reduction, and cost reduction.

[Brief description of drawings]

FIG. 1 is a block diagram showing an internal configuration of a control circuit shown in FIG.

FIG. 2 is a diagram showing a configuration of a main part of a reference example of an electric actuator for proportional control .

FIG. 3 is a time chart for explaining the operation of the control circuit shown in FIG.

FIG. 4 is a diagram showing a configuration of a main part of a first embodiment of an electric actuator for proportional control according to the present invention.

5 is a block diagram showing an internal configuration of the control circuit shown in FIG.

FIG. 6 is a time chart for explaining the operation of the control circuit shown in FIG.

FIG. 7 is another example of the control circuit shown in FIG.
It is a block diagram showing 2 ).

FIG. 8 is a diagram showing the relationship among the generated torques T1 and T2 of the drive motor and the auxiliary motor and the overall torque T in variations 1 to 8;

FIG. 9 is a main part configuration diagram showing an example of a conventional electric actuator for proportional control.

FIG. 10 is a main part configuration diagram showing another example of the conventional electric actuator for proportional control.

[Explanation of symbols]

1 ... Drive shaft, 2 ... Return spring, 3 '... Drive motor, 4 ... Reduction gear train, 7, 8, 8' ... Control circuit, 9
... Auxiliary motor, 7-1, 8-1 ... Arithmetic circuit, 7-2,
8-2 ... Pulse distribution circuit, 7-3 ... Brake circuit, 7-
4 ... Motor drive circuit, 7-5, 8-5 ... Output angle detection circuit, 8-3 ... 1st brake circuit (drive motor position holding brake circuit), 8-4 ... Drive motor drive circuit,
8-6 ... Auxiliary motor drive circuit, 8-7 ... Switching circuit, 8
-8 ... Second brake circuit (return deceleration brake circuit).

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-9-137873 (JP, A) JP-A-2-188199 (JP, A) JP-A-6-265039 (JP, A) JP-A-6- 93888 (JP, A) JP-A-2-271175 (JP, A) JP-A-11-2147 (JP, A) JP-A-3-247976 (JP, A) JP-A-3-247975 (JP, A) JP-A-9-196216 (JP, A) JP-A-10-164878 (JP, A) Practical flat 4-73670 (JP, U) Practical flat 1-180198 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) F16K 31/04

Claims (4)

(57) [Claims] 1. A drive shaft provided with a return spring, a drive motor and an auxiliary motor whose output shaft is rotationally coupled to the drive shaft via a reduction gear train, and the drive motor and the auxiliary motor . A control circuit for controlling the operation of the motor , wherein the control circuit has a detected angle smaller than a target angle to the drive motor.
If the drive motor and auxiliary motor are
Direction, the detected angle is larger than the target angle to the drive motor.
If it does, stop the drive of the auxiliary motor and then
The drive motor was driven in the reverse direction, and the target angle to the drive motor and the detected angle matched.
In the case of stopping the drive of the auxiliary motor,
An electric actuator, comprising: a circuit that holds a current of the operating position of the drive shaft by applying a brake current to the motor to generate a torque that balances the restoring force of the return spring. 2. A drive shaft provided with a return spring, a drive motor and an auxiliary motor whose output shaft is rotationally coupled to the drive shaft through a reduction gear train, and the drive motor and the auxiliary motor. A control circuit for controlling the operation of the motor, wherein the control circuit has a detected angle smaller than a target angle to the drive motor.
If the drive motor and auxiliary motor are
Direction, the detected angle is larger than the target angle to the drive motor.
If the threshold value is met, reverse the drive motor and auxiliary motor
Direction, and the target angle to the drive motor matches the detected angle
The drive motor and the auxiliary motor
An electric actuator having a circuit for holding a current position of the operation position of the drive shaft by generating a torque that flows a brake current to balance the return force of the return spring. 3. A drive shaft provided with a return spring, a drive motor and an auxiliary motor whose output shaft is rotationally coupled to the drive shaft via a reduction gear train, and the drive motor and the auxiliary motor. A control circuit for controlling the operation of the motor, wherein the control circuit has a detected angle smaller than a target angle to the drive motor.
If the drive motor and auxiliary motor are
Direction, the detected angle is larger than the target angle to the drive motor.
If it does, stop the drive of the auxiliary motor and then
The drive motor was driven in the reverse direction, and the target angle to the drive motor and the detected angle matched.
The drive motor and the auxiliary motor
An electric actuator having a circuit for holding a current position of the operation position of the drive shaft by generating a torque that flows a brake current to balance the return force of the return spring. 4. A drive provided with a return spring.
Shaft, and its output shaft rotates through a reduction gear train to this drive shaft.
A drive motor and an auxiliary motor that are coupled to each other, and
Control that controls the operation of the drive motor and auxiliary motor
A circuit, the control circuit, when the detected angle is smaller than the target angle to the drive motor, drives the drive motor and the auxiliary motor in the forward direction, to the drive motor. When the detected angle is larger than the target angle, the drive motor and the auxiliary motor are driven in the reverse rotation direction, and when the target angle to the drive motor and the detected angle match, the auxiliary motor is driven. the by the driving motor upon stopping by flowing braking current to generate a torque to balance the return force of the return spring, the drive shaft
An electric actuator having a circuit for holding the operation position of the current position .