JPH0723971U - Electric servo motor - Google Patents

Abstract

(57) [Summary] [Purpose] To provide an electric servo motor for operating a water turbine guide vane of a hydroelectric power generation facility. In an electric servomotor 10 having an output part that reciprocates by rotation of a drive shaft and is connected to a driven part,
An AC generator 15 that generates power when the ball shaft 13 is driven to rotate via a ball nut 14 by an input from a driven part is connected to the drive shaft, and the rotation of the drive shaft is stopped by the power generation of the AC generator 15. Powder brake 17 that operates in the state
Is provided on the drive shaft, and a switch 21 that connects the AC generator 15 and the powder brake 17 when the driving force of the drive shaft is lost is interposed between the AC generator 15 and the powder brake 17.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an electric servomotor for operating, for example, a water turbine guide vane of a hydroelectric power generation facility.

[0002]

[Prior art]

 An example of a conventional electric servomotor for operating a hydraulic turbine guide vane of a hydraulic power generation facility will be described with reference to FIG. Fig. 4 shows the outline of the control structure of a water turbine using an electric servomotor. In the figure, reference numeral 01 is an electric servo motor, 02 is a gate shaft, 03 is a dashpot, 04 is a speed adjusting valve device, 05 is a connecting rod, 06 is a water turbine, and 07 is a guide vane.

In a power plant using the electric servomotor 01, when the control power supply is lost, the guide vanes 07 in the water turbine 06 are acted on by the water imbalance force in the closing direction. As a result, the rod 05 is closed. And transmitted to the electric servomotor 01 through the gate shaft 02, and the electric servomotor 01 moves in the closing direction. In this case, as a result of the closing speed being accelerated, as shown in FIG. 3, the closing speed becomes faster (indicated by a chain line B in the figure) than in the case where the power control closes rapidly (indicated by a broken line A in the figure). ). As a result, at the fully closed position of the electric servomotor 01, a large impact force is generated, and since the closing speed is high, the hydraulic iron pipe rises.

Therefore, conventionally, as a method of controlling this, as shown in FIG. 4, a dash pot 03 using oil is provided, and the operation passage of oil is throttled through the speed adjusting valve device 04. The speed of acceleration is suppressed to prevent stopper collision and penstock rising.

[0005]

[Problems to be solved by the device]

 However, the conventional electric servomotor as shown in FIG. 4 has the following problems. Current power plants are oilless, and we want to avoid using oil as much as possible. If a dash pot is provided, foundation work will be required and the construction cost will be high. It is necessary to inspect the dashpot for oil leaks, deterioration, and the amount of oil, and if oil should leak into the leak channel, it will cause pollution problems. There is a sliding object such as a piston in the dashpot, and the closing speed changes when it is worn due to use.

[0006]

[Means for Solving the Problems]

 The configuration of the electric servomotor according to the present invention which solves the above-mentioned problems is an electric servomotor having an output section which is reciprocated by the rotation of a drive shaft and connected to a driven section. An AC generator that generates electric power when the drive shaft is driven to rotate is connected to the drive shaft via the, and a powder brake that operates to stop the rotation of the drive shaft by the power generation of the AC generator is provided on the drive shaft. In addition, a switch connecting the AC generator and the powder brake when the driving force of the drive shaft is lost is interposed between the AC generator and the powder brake.

[0007]

[Action]

 When the control power source that drives the drive shaft is lost, the drive shaft is driven by the input from the driven part via the output part to rotate the AC generator. By changing the AC power source obtained from this AC generator to a DC power source and supplying a predetermined amount of power to the powder brake, the rotation speed of the output shaft of the servo motor is suppressed and the servo motor is closed when the power is lost. Prevents excessive impact force and iron pipe water pressure rise.

[0008]

【Example】

 Hereinafter, a preferred embodiment of the electric servomotor according to the present invention will be described.

FIG. 1 is a schematic diagram of an electric servomotor according to this embodiment. As shown in the figure, the electric servomotor 10 includes a three-phase induction motor 11, a ball screw shaft 13 that is rotated through gears 12a to 12d, and the ball screw shaft 13 is rotatable in the axial direction and is not shown. A ball nut 14 for opening and closing the guide vanes, an AC generator 15 connected to the end of the ball screw shaft 13, an exchanger 16 for switching AC electricity from the AC generator 15 to DC electricity, and It is also provided with a powder brake 17 which is connected to the drive shaft 11a of the three-phase induction motor 11 and stops the rotation speed thereof. In the figure, 18 is a control power supply, 19 is an electric servo control device, 20 is a failure detector, 21 is a switching switch for connecting the AC generator 15 and the powder brake 17, and 22 is a position detector. .

When the powder brake 17 is excited by the DC power from the converter 16, a strong magnetic flux suppresses and stops the rotation of the drive shaft 11a by a powder disposed inside the powder brake 17. Is shown in FIG. As shown in FIG. 2, an exciting coil 32 is arranged in the powder break body 31, and a powder 35 that can be magnetized in an excited state is placed in a space 34 provided on the outer periphery of the drive member 33. ing. The powder 35 only idles when the drive member 33 is rotated in a non-excited state, but when it is excited, the powder 35 is magnetized, and the magnetic coupling force and the frictional force between the powder 35 and the operating surface cause the two to rotate. The rotation of the drive shaft 11a of the servo motor which is connected to the drive member 33 is suppressed and stopped.

That is, by increasing / decreasing the current of the converter 16, the role of the brake of the drive shaft 11a of the three-phase induction motor 11 and the slip operation are performed.

In the above configuration, the electric servomotor 10 in the normal operation controls the three-phase induction motor 11 by the electric servo control device 19, rotates the ball screw shaft 13 by a predetermined amount, and detects the position detector 22. By reciprocally moving the ball nut 14 to a predetermined position in the axial direction, a guide vane (not shown) as a driven portion is opened and closed.

Next, when the control power supply 18 is lost, the failure detector 20 detects an abnormality of the electric servomotor control device 19, and the changeover switch 21 is switched to change the normal time converter 16 and the control device 19. The connection state of the AC generator 15 and the exchanger 16 is switched from the connection state of the AC generator 15 to the exchange unit 16 at the time of abnormality.

When the power source 18 of the electric servo controller 16 is lost, a force acts in the closing direction due to the hydraulic imbalance of the guide vanes, and the ball nut 14 moves in the axial direction (moves leftward in the figure), Due to this, the ball screw shaft 13 is driven to rotate, and the gears 12a to 12d and the AC generator 15 are driven.

The changeover switch 21 is changed over by the failure detector 20 and sends the electric power generated by the AC generator 15 to the converter 16 which is an AC / DC power supply device. The converter 16 replaces the AC power supply of the AC generator 15 with a DC power supply and supplies necessary power to the powder brake 17. As a result, the rotation of the output shaft 11a is suppressed by the operation of the powder brake 17 as described above, and the rotation speed thereof is suppressed.

Therefore, in the operation of the servo motor, an excessive impact force and an increase in iron pipe water pressure in the fully closed state due to power loss are prevented.

In this embodiment, the drive shaft is the ball screw shaft 13, and the ball nut 14 screwed to the ball screw shaft 13 is used as the output part to open and close the guide vane (not shown) that is the driven part. However, the present invention is not limited to this, and is applied to a motor that opens and closes the guide vanes when the ball nut 14 is driven to rotate and the ball screw shaft 13 is driven to rotate to reciprocate in the axial direction. The rotation of the ball nut 14 may be stopped.

Further, in the present embodiment, the motor having a plurality of output shafts has been described, but a single drive shaft is provided, and an alternating current generator and a powder brake are arranged on the single drive shaft to further reduce the size. You may

In addition to the AC generator (AG) described above, other means such as a battery or an external power source (including AG mounted on the generator) is used to supply power to operate the powder brake. You may do it.

[0020]

[Effect of device]

 As described above with reference to the embodiments, the electric servomotor of the present invention has the following effects. By mounting the AC generator and the powder brake as the drive shaft restraining means on the electric servomotor, it is possible to make the device compact compared to the conventional device having the restraining means provided outside. The conventional dashpot is no longer required, and the foundation work and its maintenance and inspection work can be omitted, and simplification can be achieved. The closing time of the electric servomotor at the time of power loss can be easily adjusted by adjusting the ratio of power consumption.

[Brief description of drawings]

FIG. 1 is a schematic diagram of an electric servomotor according to an embodiment.

FIG. 2 is a schematic view of a powder brake.

FIG. 3 is a graph showing a relationship between a servo stroke of a servo motor and a closing time when power is lost.

FIG. 4 is a schematic view of a conventional electric servomotor.

[Explanation of symbols]

 10 Electric Servo Motor 11 Three-Phase Induction Motor 13 Ball Screw Shaft 14 Ball Nut 15 AC Generator 16 Exchanger 17 Powder Brake 18 Control Power Supply 19 Electric Servo Controller 20 Failure Detector 21 Changeover Switch

Claims (1)

[Scope of utility model registration request] 1. An electric servomotor having an output part that reciprocates by rotation of a drive shaft and is connected to a driven part,
An AC generator, which generates power when the drive shaft is driven to rotate via the output unit by input from the driven unit, is connected to the drive shaft, and the AC generator operates to stop rotation of the drive shaft. An electric motor characterized in that a powder brake is provided on the drive shaft, and a switch connecting the AC generator and the powder brake is interposed between the AC generator and the powder brake when the drive force of the drive shaft is lost. Servomotor.