JP2001176360A - Fluid-power drive device of circuit breaker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve such problems that when the retention of a toggle mechanism acts at the time of operation, it becomes resistant to the driving force, and when the retention is strong, actions of a control valve are harmed, and when the retention is weak, the control valve becomes unstable at the time of start-up and suspension. SOLUTION: A valve body of the control valve is provided with a taper part or a groove, and a piston is arranged, which contacts with the taper part or the groove of the valve body by receiving a force of a spring mechanism from the back. On the side of the valve body of this piston, a pressure chamber connecting to the supply-pressure side is arranged, and the spring-mechanism side of the piston is connected to the low-pressure side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a configuration of a fluid pressure driving device for opening and closing contacts of a power circuit breaker.

[0002]

2. Description of the Related Art Since a power circuit breaker provided to protect a power supply system in an emergency such as a lightning strike requires an extremely high-speed opening and closing operation, a fluid pressure drive device for driving the circuit breaker controls a large flow rate. A valve is required. Therefore, a pilot-operated control valve that obtains a large flow rate by hydraulically driving a large control valve with a small pilot valve is used. However, the control valve is a mechanism that switches between the open circuit operation state and the closed circuit operation state depending on the level of the pressure, so when the fluid pressure source is stopped, there is no accumulation in the accumulator and the supply of high pressure is stopped, the control valve The position of the valve cannot be maintained. Therefore, in a conventional fluid pressure drive device of a circuit breaker, for example, as described in Japanese Patent Application Laid-Open No. 1-239719, a toggle mechanism for pressing and fixing a ball by a spring force into a groove or the like provided in a valve body is used. Was used.

[0003]

In the above-mentioned prior art configuration, the spring force of the toggle mechanism always acts on the valve body regardless of the level of the fluid pressure. Resistance of the pilot operation force. For this reason, if the spring is strengthened so that it can be held firmly without pressure, the driving force of the control valve decreases, so that the operation is slowed down, the operation is susceptible to pressure fluctuation, and the operation time varies. And other problems occur. However, if the pilot operation force is increased to solve this problem, the pilot chamber becomes larger and the flow rate required for the pilot valve becomes larger, so that the hydraulic drive becomes larger, or the operation of the control valve becomes larger. Problems occur such that high performance cannot be obtained due to low speed.

On the other hand, if the spring is weakened to avoid such a problem, the pressure balance of the pilot operation system is reduced in the process of decreasing the pressure in order to stop the fluid pressure driving device and in the process of starting and increasing the pressure. In some cases, the valve body of the control valve may move due to slight collapse. In addition, the valve body may move due to vibration or impact during transportation. Then, there arises a problem that the circuit breaker moves at the time of stop or start, causing a dangerous state, or a problem that the high-pressure supply side communicates with the low-pressure return side at the time of start, so that the pressure cannot be increased.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems in the prior art, to obtain a small and high performance stably, and to achieve a high reliability and safety of a fluid pressure drive device for a circuit breaker. Is to provide.

[0006]

In order to achieve the above object, according to the present invention, at least one tapered portion or groove is provided in a part of a valve body of a control valve, while the tip of the control valve receives a force of a spring mechanism from behind. Is provided with a piston that contacts the tapered portion or groove of the valve element, and a pressure chamber that is connected to the supply pressure side is provided on the side of the piston that contacts the tapered portion or groove, and the spring mechanism side of the piston is connected to the low-pressure side. A toggle mechanism is provided.

Accordingly, in the normal operation state in which high pressure is supplied, the force acting from the pressure chamber connected to the supply side overcomes the spring force and separates the piston of the toggle mechanism from the valve body. The holding force does not become the resistance force of the pilot operation force, and the force that separates the piston from the valve body by the fluid pressure is large, so that the spring force can be sufficiently increased. It can be held more firmly.

Therefore, according to the present invention, it is possible to realize a fluid pressure drive device for a circuit breaker having a small size and high performance stably obtained and having high reliability and safety.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the fluid pressure driving device for a circuit breaker according to the present invention will be described below with reference to FIGS.
FIG. 1 shows a state in which the fluid pressure driving device is stopped with the circuit breaker open (cut), and FIG. 2 shows a state in which the circuit breaker is closed (closed) with the fluid pressure driving device operated to supply high pressure. Show.

A fluid pressure driving device 3 for a circuit breaker, which comprises a fixed contact 1 and a movable contact 2 and opens and closes a contact, includes a fluid pressure cylinder 4 for driving the movable contact 2 with a piston 5. The supply pressure of the working fluid discharged from the fluid pressure source 8 and stored in the accumulator 9 always acts on the small pressure receiving area 6, and the large pressure receiving area forming the cylinder operating chamber 7 has a control valve having a valve body 12. 11 is selectively connected to a high pressure supply pressure side or a low pressure return side leading to the reservoir 10.

The control valve 11 excites the open circuit solenoid 15 and the pilot valve 14 controls the control valve pilot chamber 1.
3 is switched to a low pressure to open the cylinder operating chamber 7 at a low pressure to open the circuit. Conversely, the closing solenoid 16 is excited, and the pilot valve 14 controls the control valve pilot chamber 1.
By switching 3 to a high pressure, the cylinder operation chamber 7 is set to a high pressure to perform a closing operation.

At one end of the valve body 12 of the control valve 11, a taper portion 18 opposite to the taper portion 17 is provided. The taper portion 17 is in the open operation state, and the taper portion 18 is in the close operation state.
The pistons 21 and 22 having the balls 19 and 20 at the tip are provided so as to face each other. The pressure chambers 23 and 24 connected to the supply side are provided on the valve body side of the pistons 21 and 22, while the spring 2 is provided on the opposite side of the valve body.
5 and 26 and the space containing the spring is connected to the low pressure return side.

Next, the operation of this embodiment will be described.

With the above configuration, when the fluid pressure driving device is stopped, the pressure in the pressure chambers 23 and 24 becomes low, so that the pistons 21 and 22 are pressed toward the valve body by the forces of the springs 25 and 26. For example, as shown in FIG. 1, when the fluid pressure driving device is stopped in a state where the circuit breaker is opened (cut), the force of the springs 25 and 26 is applied from the balls 19 and 20 to the valve body via the tapered portion 17. 12 acts to keep the circuit open. On the other hand, when stopping in the closed (closed) state, the forces of the springs 25 and 26 act to maintain the valve body 12 in the closed operation state from the balls 19 and 20 via the tapered portion 18. That is, these constitute a toggle mechanism.

As shown in FIG. 2, when the fluid pressure source 8 is activated to supply a high pressure, as the pressure chambers 23, 24 become high pressure, the forces of the springs 25, 26 are overcome and the piston 2
Separate 1, 22 from the valve body. For this reason, in a normal operation state in which a high pressure is supplied, the holding force of the toggle mechanism by the springs 25 and 26 does not act on the valve body 12, so that the resistance force of the pilot operation force for driving the valve body 12 by the fluid pressure. It does not become.

Therefore, according to this embodiment, the valve element holding force at the time of stopping and the valve element driving force at the time of operation can be determined separately, so that the valve element is firmly held at the time of starting or stopping. Thus, the valve body driving force during operation can be minimized while providing sufficient spring force. as a result,
Since the trouble that the circuit breaker moves at the time of starting and stopping or the voltage cannot be increased during the starting does not occur, safety and reliability are improved. Further, since the diameter of the control valve pilot chamber 13 can be reduced to minimize the flow rate required for pilot operation, the control valve and the pilot valve can be downsized, and the capacity of the pilot valve can be given a margin. High-speed operation can be obtained more stably.

Next, another embodiment of the fluid pressure driving device for a circuit breaker according to the present invention will be described with reference to FIG. In the present embodiment, FIG.
In the embodiment shown in FIG. 2, screws 30 and 31 and lock nuts 32 and 3 are provided on opposite sides of the springs 25 and 26 from the piston.
3 is an example in which the forces of the springs 25 and 26 are adjusted by the screws 30 and 31 and then the locks can be fixed using the lock nuts 32 and 33.

According to this embodiment, the force acting from the pressure chambers 23, 24 overcomes the force of the springs 25, 26 and the piston 2
The pressure at which the valves 1 and 22 start to be separated from the valve body and the valve body holding force when the fluid pressure driving device is stopped can be adjusted according to the use conditions and characteristics of the device.

As shown in FIG. 4, the tapered portions shown in the above embodiments may be arc-shaped grooves 40, 41 having a larger radius of curvature than the balls 19, 20. A similar effect can be obtained with this configuration.

[0020]

As described above, according to the present invention, the holding force of the toggle mechanism acts on the valve element only when the fluid pressure driving device is stopped, so that the valve element can be firmly held at the time of starting or stopping. The valve body driving force at the time of operation can be minimized while providing a sufficient spring force. Therefore, a small and high performance can be stably obtained, and a fluid pressure drive device for a circuit breaker having high reliability and safety can be realized.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a state in which a fluid pressure driving device according to an embodiment of the present invention is stopped in an open circuit state.

FIG. 2 is a cross-sectional view showing a closed state in a state where the fluid pressure driving device of FIG. 1 is operated.

FIG. 3 is a sectional view showing another embodiment of the present invention.

FIG. 4 is a sectional view showing a modification of the embodiment of FIG. 1;

[Explanation of symbols]

12 ... valve element, 17, 18 ... taper part, 21, 22, ... piston, 23, 24 ... pressure chamber, 25, 26 ... spring, 30,
31 ... screws, 40, 41 ... grooves.

Claims (1)

[Claims] 1. A hydraulic cylinder for opening and closing a contact, a control valve for opening or closing the hydraulic cylinder, a pilot valve for switching the control valve between an open state and a closed state, and a working fluid. A fluid pressure drive device for a circuit breaker including a fluid pressure source for pressurizing and supplying, an accumulator for accumulating a working fluid pressurized and supplied from the fluid pressure source, and a reservoir for collecting and storing the discharged working fluid. Providing at least one tapered portion or groove in a part of the valve body of the control valve, and providing a piston whose tip abuts the tapered portion of the valve body under the force of a spring mechanism from behind, A pressure chamber connected to the supply pressure side is provided on the side that comes into contact with the tapered portion or the groove, and a toggle mechanism that connects the spring mechanism side of the piston to the low pressure side is provided. It sectional detect a fluid pressure driven device.