JPH0230985A - Protective device for electrically driven servo-motor of hydraulic machinery - Google Patents

Abstract

PURPOSE:To enhance reliability as a protective device for an electrically driven servo-motor by connecting the electrically driven servo-motor for driving a guide vane with a protective drive device, and thereby providing a clutch which switches guide drive transfer force. CONSTITUTION:An electrically driven servo-motor 18 for driving a guide vane 1 is connected with a protective drive device 11 over the axial line of a gate shaft 3 which drives a guide ring 2 for driving the guide vane 1. And a clutch 9 switching guide vane driving transfer force is provided between the electrically driven servo-motor 18 and the protective drive device 11. This constitution can thereby enhance reliability as a protective device for the electrically driven servo-motor.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention provides a protection device for an electric servo motor that operates a guide vane that adjusts the amount of inflow water or the amount of water discharged in hydraulic machines such as water turbines and pump water turbines. Related (Prior Art) In recent years, electric servo motors have been increasingly used to operate guide vanes of water turbines in small and medium-sized hydroelectric power plants in order to reduce construction and maintenance costs.

In this type of electric servo motor, it is necessary to convert the relatively high-speed, low-torque, reversible rotational motion of the electric motor into relatively low-speed, high-load, reciprocating linear motion.
As shown in Publication No. 5, roller bearings such as ball screws, ball nuts, ball bearings, and tapered roller bearings are used as components of the main movable parts. In these roller bearings, if damage occurs to the inner race, ball screw, outer race, ball, or contact surface with the rollers due to long-term use or contamination with foreign matter, the amount of heat generated will increase due to increased bearing loss or decreased power transmission efficiency. The damage increases and the damage progresses to rapid expansion and seizure, and parts that should normally move relative to each other become mechanically locked.

Although the possibility of such a situation occurring is minimal in absolute terms compared to hydraulic cylinders, which have been widely used to operate guide vanes in conventional hydraulic machinery, electric servo motors There are far more. Furthermore, when seizure occurs in roller bearings, it is often accompanied by deformation or popping out of the balls or rollers, and destruction of the inner race and outer race, so mechanical locking occurs instantaneously. Furthermore, as bearing loss increases and power transmission efficiency decreases, the amount of heat generated by the motor itself tends to increase, and as this progresses, insulation breakdown of the motor coil occurs and the motor becomes unable to rotate or generate torque. Become. Then, the guide vane becomes inoperable and in a free state (a state dominated by the hydraulic moment applied to the guide vane). Such a state also occurs when a motor drive power source is lost or a motor control device malfunctions.

As mentioned above, due to the structural limitations of the electric servo motor itself, compared to the conventional hydraulic cylinder structure used in the membrane, there is a possibility that the electric servo motor itself will be mechanically locked and malfunction, resulting in inoperability. It contains significantly more. If such a failure occurs, not only will it cause sudden frequency fluctuations and load fluctuations in the generator, but especially if the guide vane becomes free, there will be an abnormal increase in water pressure in the iron pipe and casing, and damage to the water turbine and rotating parts of the generator will occur. At the same time, if the load of the generator is interrupted, the rotation of the turbine and generator will continue to increase to the launchway rotation speed, resulting in damage to the hydropower plant structure. There will also be danger.

Therefore, in hydroelectric power plants that use electric servo motors, in order to prevent the guide vanes from becoming free, the guide vanes should be self-closing, or a weight or pneumatic cylinder that moves the guide ring in the closing direction should be used. If a protective device such as an air motor is installed and the electric servo motor is mechanically locked at a certain opening,
Many methods are used, such as blocking the flow of water through large valves.

Furthermore, as a protection device when a mechanical locking phenomenon occurs in an electric servo motor, for example,
As shown in Japanese Patent No. 426, a system is also adopted in which the electric servo motor base itself is equipped with a fluid servo motor, and the electric servo motor base itself is moved in the guide vane closing direction in an emergency.

(Problem to be solved by the invention) However, when the guide vane is of a self-closing type, it is necessary to generate a closing side hydraulic moment over the entire range of the guide vane opening. Compared to the guide vane type which is close to the balanced type, the maximum closing side water camouflage amount is approximately twice as much. Accordingly, the operating force of the electric servo motor normally used to operate the guide vane is almost doubled, which increases the capacity of the electric servo motor, which is uneconomical.

Further, the hydraulic moment applied to the guide vane is variable and generally changes significantly depending on the opening degree of the guide vane. Therefore, in an emergency situation where the electric motor rotation speed cannot be controlled, the closing speed of the guide vane cannot be controlled, and if it is slower than the optimum closing speed, the increase in rotation of the water turbine cannot be suppressed within the specified value, and the guide vane closes. If the closing speed of the pipe is fast, the increase in water pressure of the iron pipe cannot be suppressed within the specified value.

In the case of a protection device in which a weight is provided on the guide ring and a moment is applied to the normally closed side, the electric servo capacity becomes large, which is uneconomical, and the closing speed cannot be controlled.

If a device that closes using fluid pressure such as compressed air or water pressure is provided, such as an air cylinder, an air motor, or a water pressure cylinder, the capacity of the electric servo motor will not be large enough in the above case. However, even in normal operation, the air cylinder, water pressure cylinder, or rotor of the air motor follows the movement of the electric servo motor under no load, so the power from the sliding resistance is used as the electric servo motor. This would be uneconomical.

Additionally, it will unnecessarily shorten the lifespan of these devices, which is not only uneconomical in this respect, but also increases the possibility that these cylinders, air motors, etc. will fail during normal operation and become mechanically locked. Therefore, such usage is not preferable because it causes a decrease in the reliability of the protection device itself.

In the case of a system in which a fluid cylinder is installed at the base of the electric servo motor and the entire electric servo motor is moved to the closed side in an emergency, the fluid cylinder is prevented from operating even if the electric servo motor receives the maximum operating force normally generated. must be maintained by fluid pressure or spring force. In the case of a system that maintains fluid pressure, if the fluid pressure drops or is lost, the electric servo motor will operate due to the operating force generated, and it may become uncontrollable even if there is no abnormality in the electric servo motor itself. There is sex. When the fluid cylinder is always held in place by spring force, when it operates, it must generate a force greater than the electric servo motor operating force against the spring force, so the capacity of the fluid cylinder The capacity must be more than twice that of the electric servo motor, and together with the spring device, this equipment itself becomes very expensive and uneconomical.

In addition, if the electric servo motor is uncontrollable, it is possible to cut off the water flow to the large mouth valve, but this is the final protection method, and assuming an accident where the large mouth valve is damaged due to vibration or shock caused by the water cutoff, Until the iron pipe water intake gate is closed, there is a possibility that serious accidents such as iron pipe water leaking into the power plant may occur.

Therefore, considering the operational reliability of the entire hydroelectric power plant, it is not preferable to use this protection method to directly protect the electric servo motor itself.

SUMMARY OF THE INVENTION The present invention has been made in view of the drawbacks of conventional protection devices for electric servo motors for operating guide vanes of hydraulic machines, and an object of the present invention is to provide a protection device that is sufficiently reliable as a protection device and can be supplied at an optimal cost. The purpose is to

[Structure of the invention]

(Means for Solving the Problem) In order to achieve the above object, the present invention provides an electric servo motor for driving the guide vane and a protection drive on the axis of the gate shaft for moving the guide ring for driving the guide vane. The present invention is characterized in that a clutch is provided between the electric servo motor and the protection drive device for switching the guide vane drive transmission force.

(Function) According to the present invention, since the mechanical connection between the electric servo motor and the gate shaft is performed by a spring-biased clutch, the electric servo motor can When the motor is in a normal state, the mechanical connection will not become disconnected and reliable guide vane control can be performed. In addition, this clutch is switched to the protection drive device side using the same fluid pressure as the operating fluid pressure of the protection drive device, and since the electric servo motor uses a self-locking type, the protection drive When the device fluid pressure is lost, the clutch does not operate and the mechanical connection between the electric servo motor and the gate shaft is ensured, so the guide vane does not become free. Furthermore, since the clutch is mechanically connected to both the electric servo motor and the protection drive device during clutch switching, the guide vane does not become free even in this state.

(Example) Hereinafter, the present invention will be described in detail based on an example shown in the drawings.

1 to 4 are a vertical sectional view around a gate shaft when an embodiment of the present invention is applied to a horizontal shaft water turbine, which is an example of a hydraulic machine, and a conceptual diagram and a system diagram of devices related thereto.

In FIG. 2, a guide vane 1 of a water turbine is connected to a guide ring 2 via a link, and this guide ring 2 is connected to a gate shaft 3 with a bell crank 4 and a connecting rod 5.
are connected via.

This gate shaft 3 is rotatably supported via a gate shaft bearing 6, as shown in FIG. On the axis of the gate shaft 3 located on the opposite side of the bell crank 4 with the gate shaft bearing 6 in between, there is a space between a part of the stepped collar formed on the gate shaft 3 and the ring key 7a in the axial direction. A gate arm 8 is fitted so as to be immovable and rotatable relative to the gate shaft 3. As shown in FIG. 3, unevenly spaced trapezoidal grooves 8a are formed on the side surface of the gate arm 8, and a clutch plate 9 is engaged with the trapezoidal grooves 8a.

This clutch plate 9 is attached to the gate shaft 3 via a keyway 10 so as to be non-rotatable but relatively movable in the axial direction.

On the side surface of this clutch plate 9, unevenly spaced trapezoidal projections 9a that mesh with the gate arm side are formed, and unevenly spaced trapezoidal projections 9b that mesh with this are formed on the protector arm 11 side. It is formed. This protector arm 1
1 is fitted between a stepped portion formed on the gate shaft 3 and the ring key 7b via a needle bearing 12 so as to be immovable in the axial direction but rotatable with slight resistance with respect to the gate shaft 3. ing. Furthermore, the protection device arm 11 is formed with equidistant trapezoidal grooves 11a that engage with the protrusions 9b on the side surface on the clutch plate 9 side. Further, a clutch operating cylinder 13 is fitted near the shaft end of the gate shaft 3 on the protector arm 11 side, and this clutch operating cylinder 13 is fixed to the clutch plate 9 via a clutch operating rod 14. Furthermore, gate shaft 3
A spindle 15 is fixed to the shaft end of the spindle 15, and the other end of the spindle 15 passes through the clutch operation cylinder 13 and extends to the outside.At the same time, a small hole 15a for a compressed air passage is formed in the center of the spindle 15. has been done. An axially movable spring receiver 16 is fixed to the spindle 15, and a disc spring 17 is mounted in a compressed state between the spring receiver 16 and the clutch operation cylinder 13.

Further, an electric servo motor 18 is pin-coupled to the gate arm 8, as shown in FIG. 3, and an air cylinder 19 is pin-coupled to the protection device arm 11, as shown in FIG. This electric servo motor 18 uses a worm and a single wheel as a speed reduction device. This is a self-locking type that can maintain its position even if the operating rod receives a reaction force of the maximum capacity of the electric servo motor when no torque is generated in the electric motor. As shown in FIG. 1, an air tank 20 is provided as a driving source for the air cylinder 19, and compressed air is constantly stored in the air tank 20. This air tank 20 is connected to the air cylinder 1 via a solenoid valve 21 and a closed-side operation pipe 22.
It is connected to the closed side boat 9 and also to the end of the spindle 15 via a clutch operation pipe 23.

The solenoid valve 21 normally cuts off air supply from the air tank 20 and communicates the closed-side operating pipe 22 and the clutch operating pipe 23 with the atmosphere. If the electric servo motor 18 has fallen into an uncontrollable state, for example, the motor operating current is higher than a specified value, the water turbine rotation speed has reached acceleration, the governor power supply has been lost, the motor operating power supply When the solenoid is energized under the condition that the solenoid is lost, the air tank 20, the closing side operating pipe 22, and the clutch operating pipe 23 are made to pass through.

The gate shaft bearing 6 is provided with a clutch pressure distributor 24 that operates on the condition that the clutch plate 9 is completely switched to the gate arm 8 side, and the air cylinder 19 is provided with a clutch pressure distributor 24 that operates on the condition that the clutch plate 9 is completely switched to the gate arm 8 side. An air cylinder pressure distributor 25 is provided which operates under the following conditions. Further, an open side operation pipe 26 extending from the air tank 20 is connected to an open side port of the air cylinder 19 via a clutch pressure distributor 24 and an air cylinder pressure distributor 25.

Next, the operation of this embodiment will be explained.

FIG. 1 shows a normal state, that is, a state in which the guide vane 1 is mechanically connected to the electric servo motor 18. In this figure, the gate shaft 3 has a radial direction,
Even when a force in the thrust direction is applied, the gate shaft 3 is maintained in a fixed state and freely rotatable state by the gate shaft bearing 6. Also,
The repulsive force of the disc spring 17 is constantly exerted by the clutch operation cylinder 13.
, acts on the gate arm 8 via the clutch operating rod 14, and the force is sufficiently larger than the thrust direction component force generated by the maximum rotational torque of the trapezoidal groove 8a formed in the gate arm 8, so that the clutch plate 9 The trapezoidal protrusion 9a and the trapezoidal groove 8a of the gate arm 8 are engaged, and torque is transmitted between them, and at the same time, the gate arm 8 and the clutch plate 1 always move in the same manner.

Therefore, the operating amount and operating force of the operating rod 18a of the electric servo motor 18 are transmitted to the guide vane 1 through the path of the gate arm 8, clutch plate 9, gate shaft 3, bell crank 4, connecting wood 5, and guide ring 2. Ru.

Since this electric servo motor 18 is a self-locking type, after the guide vane 1 is operated to the target opening degree, no current is applied to the electric motor 18b, that is, the electric motor 18b is in a state in which it does not generate rotational torque.

At this time, the operating rod 18a of the electric servo motor 18 transfers the hydraulic moment generated in the guide vane 1 through the guide ring 2, connecting rod 5, bell crank 4, gate shaft 3, clutch plate 9, and gate arm 8. Although the guide vane is receiving the guide vane, it does not operate, so the guide vane always maintains a constant opening degree.

As described above, the electric servo motor 18 and the guide vane 1 are mechanically connected in the normal state, and the guide vane 1
The opening degree of is controlled by the movement of electric servo motor 18.

Here, the bearings that are the components of the electric servo motor 18 seize, and the electric motor 18b burns out. If any failure occurs, such as a loss of motor power, or if a failure occurs in the governor system,
The abnormality is electrically detected directly or indirectly, and the solenoid valve 21 is energized. When the electromagnetic valve 21 is energized, compressed air in the air tank 20 simultaneously flows to the spindle 15 and the closed port of the air cylinder 19 through the closed side operating pipe 22 and the clutch operating pipe 23 . Then, the compressed air guided through the small hole 15a of the spindle 15 flows into the clutch operating cylinder 13, and the clutch operating cylinder 13 moves against the clutch plate 9 against the repulsive force of the disc spring 17.
is pressed against the protective device arm 11 side. Therefore, the end face of the trapezoidal groove of the clutch plate 9 and the end face of the trapezoidal protrusion of the protection device arm 11 come into contact with each other, or if the positions of the trapezoidal groove and the trapezoidal protrusion are aligned, they engage as they are. In the case where the end face is pressed, the operating rod 19a has already been pressed.
Since the protection device arm 11 has started to move toward the closing side, the protection device arm 11 has started to rotate, and if the trapezoidal groove portion and the protrusion portion rotate by one pitch at most, they will be in an engaged state. During this operation, the clutch plate 9 is engaged with the gate arm 8 side until it is completely engaged with the protector arm 11 side.
The gate shaft 3 is in a restrained state with respect to the electric servo motor 18. The reason why the opening degree of the guide vane 1 does not change is because the stroke of the clutch plate 9 is minute and the above operation is performed instantaneously.

When the clutch plate 9 and the protective arm 11 are completely engaged,
Since the restraint between the gate arm 8 and the clutch plate 9 is released, the operating rod 19a moves to the closing side, and the closing side movement and operating force of the air cylinder 19 are controlled by the protection device arm 11,
It is transmitted to the guide vane 1 via the clutch plate 9, gate shaft 3, bell crank 4, operating rod 5, and guide ring 2, and the guide vane 1 moves toward the closing side to be fully closed.

This cuts off the amount of water flowing into the water wheel, and the water wheel comes to a halt.

Next, when the failure location is identified and the system is restored, the operating rod 18a of the electric servo motor is in the fully closed state and the guide vane 1 is held in the fully closed state, so the gate arm 8 and the clutch plate 9 The trapezoidal groove and the trapezoidal protrusion are at the same initial relative position. When the solenoid valve 21 is de-energized in this state, the closing-side operation tube 22 and the clutch operation tube 23 are in the exhaust state, so the air inside the clutch operation cylinder 13 is exhausted, the operation force due to air pressure is eliminated, and the disc spring 17 Due to the repulsive force, the clutch operation cylinder 13 presses the clutch plate 9 against the gate arm 8 side.

When the clutch plate 9 is completely engaged with the gate arm 9, the clutch pressure distributor 24 is brought into communication with the open side operation pipe 26. Furthermore, since the air cylinder pressure distributor 25 is in communication with the closed-side operating pipe 26, the compressor air in the air tank 20 is guided to the open-side port of the air cylinder 19, and the operating rod 19a of the air cylinder 19 is It moves in the opening direction and reaches the fully open position. In this state, the air cylinder pressure distributor 25 shuts off the open side operation pipe 26 and at the same time puts the open side port of the air cylinder 19 into the exhaust state. This operation restores a complete normal operating state.

As described above, according to this embodiment, when the electric servo motor falls into an uncontrollable state, the guide vane can be reliably closed with a minute delay time and at the optimal closing speed.
It becomes possible to suppress the water pressure increase and speed increase to the minimum,
The reliability of the water turbine structure and generator rotating body structure is improved.

In addition, when stopping, during normal operation, when switching to a protective device, etc.
Since the guide vane does not become free in any condition, it is possible to prevent an abnormal rise in the water pressure of the iron pipe due to the fluttering of the guide vane, and to prevent damage to the guide vane or the operating mechanism, thereby improving reliability in this respect as well.

For other equipment and equipment, if it is determined in advance that it is better to stop operation urgently depending on the location and severity of the failure, switching to emergency closure can be performed via a solenoid valve if it is incorporated into the electrical sequence. This also improves the general reliability of power plant operations.

On the other hand, in steady operation, when there is no need to adjust the opening of the guide vane, the electric power generated by the electric servo motor is 0, and the compressed air to the protective air cylinder is supplied to the pressure regulator and solenoid valve. Since the compressed air is shut off by , the compressed air consumption is 0, making economical operation possible.

In the above embodiment, an air cylinder was used as an example of the protection device, but the same structure can be implemented even if other fluid cylinders such as water pressure, nitrogen gas, etc. are used.

In addition, if the electrical sequence is set to switch to the protective device side when a sudden closing signal is issued from the speed governor due to load shedding, etc., the electric servo motor only needs to perform normal relatively slow opening/closing operations. , the capacity of the electric servo motor is much smaller, making it compact and economical. Since the capacity of the motor is also reduced accordingly, the power supply device and control device within the motor can also be of small capacity, making it economical from this point of view as well.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, the guide vane is mechanically coupled to the electric servo motor when the electric servo motor is operating normally, and when the electric servo motor is out of control. When the protection drive device is mechanically connected to the electric servo motor, the connection with the electric servo is disconnected, and during switching or when the drive source of the protection drive device is 0, the mechanical connection with the electric servo motor is disconnected. Since the connection is maintained and the guide vane is restrained by the electric servo motor, it is possible to provide a highly reliable protection device for the electric servo motor.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of the present invention, FIG. 2 is a sectional view taken along the line ■-■ in FIG. 1, FIG. 3 is a sectional view taken along ■--■ in FIG. 1, and FIG. 4 is a sectional view taken along the line It is a TV-IV sectional view of. 1... Guide vane, 2... Guide ring, 3...
・Gate shaft, 6... Gate shaft bearing, 8.
...Gate arm, 9...Clutch plate, 10...Ki, 11...Arm for protection device, 13...Clutch operation cylinder, 14...Rod for clutch operation, 11
5...Spindle, 16...Spring receiver, 17
...Disc spring, 18...Electric servo motor, 18b.
...Electric motor, 19...Air cylinder 19a...
Operating rod, 20... Air tank, 21... Solenoid valve, 24... Clutch pressure distributor, 25... Air cylinder pressure distributor.

Claims (1)

[Claims] An electric servo motor for driving the guide vane and a protection drive device are connected on the axis of the gate shaft for moving the guide ring for driving the guide vane, and a guide is connected between the electric servo motor and the protection drive device. An electric servo motor protection device for a hydraulic machine, characterized by being provided with a clutch for switching vane drive transmission force.