JPH0241808Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a vacuum valve, and particularly to the structure of a fixed electrode shaft.

[Technical background of the invention and its problems]

Generally, a vacuum valve has a cylindrical envelope formed from an insulating material such as borosilicate glass, and has a small difference in coefficient of thermal expansion between the two ends of the envelope.
An end plate is provided through a metal ring made of a Fe-Ni alloy to form a vacuum container, and a pair of electrodes are disposed inside the vacuum container so that they can be freely connected and separated. A shield is placed inside the vacuum vessel to prevent metal vapor generated by the high-temperature arc from adhering to the surfaces of the envelope and bellows, reducing their insulation and airtightness. In addition,
If the rated voltage is low, some models have a shield attached to a fixed shaft.

By the way, these parts are usually assembled by brazing in a vacuum atmosphere, which increases the number of manufacturing steps and takes a long time.Moreover, a relatively large amount of silver solder, which is an expensive material, must be used, so the manufacturing process is slow. The cost of the assembly process accounts for a considerable amount of the cost.

Therefore, efforts are being made to downsize parts and reduce the amount of silver solder used as a brazing material.
This is also approaching its limit, and the development of an even cheaper structure is desired.

On the other hand, since a vacuum valve is subjected to a considerable impact force when its electrodes are opened and closed, there is a risk that the brazed parts of the parts may be damaged and fall off. however,
Vacuum valves are built into vacuum circuit breakers and connected to important power circuits, and control the starting and stopping of various devices that serve as loads. Vacuum valve accidents pose a major hindrance to plant operation, and a solution to this problem is also desired. It is rare.

[Purpose of the invention] The present invention was made in view of the above-mentioned circumstances, and aims to provide a vacuum valve that has a simple structure, is easy to assemble, and is inexpensive and highly reliable.

[Summary of the idea]

In the present invention, a vacuum container is formed by providing end plates at both end openings of an envelope formed of an insulating material, and a fixed shaft having a fixed electrode fixed to the end is provided on one end plate, and the other The end plate of the vacuum valve has a movable electrode fixed to the end that can freely come into contact with and separate from the fixed electrode.A vacuum valve has a movable electrode that can be moved freely via a bellows, and the fixed shaft has a fixed electrode fixed to one end. A fixed shaft main body, a substantially disk-shaped base connected to the other end of the fixed shaft main body, and a cylindrical shield coaxial with the fixed shaft main body and surrounding both electrodes are integrally formed, and a disk-shaped The outer surface of the base has a part that is approximately flush with the outer surface of the end plate, and by omitting the need for shield brazing, assembly is facilitated, the amount of expensive silver solder used is reduced, and reliability is improved. It is.

[Example of idea]

Hereinafter, one embodiment of the vacuum valve of the present invention will be described with reference to the drawings. In FIG. 1, a vacuum valve 1 has a cylindrical envelope 2 formed from an insulating material, and an Fe-Ni alloy made of an Fe-Ni alloy having a small difference in thermal expansion coefficient from the envelope 2 at both end openings. metal ring 3
and a vacuum vessel 7 provided with end plates 5 and 6 via 4 and 4, respectively, and evacuated to 1×10 ^-2 Pa or less;
A fixed shaft 9 is provided to be connected to the end plate 5 and has a fixed electrode 8 fixed to the end thereof, and a movable electrode is provided to be movably provided to the end plate 5 via a bellows 10 and can freely move toward and away from the fixed electrode 8. 11 is fixed to the end of the movable shaft 12
It consists of In addition, the code 13 in the same figure is
This is a shield for preventing vapor generated during opening and closing of the vacuum valve from adhering to the bellows 10.

Thus, the fixed shaft 9 described above is composed of a fixed shaft main body 15 to which the fixed electrode 8 is fixed at one end, and a substantially disc-shaped base 16 connected to the other end of the fixed shaft main body 15. A cylindrical shield 17 is attached to the base 16 coaxially with the fixed shaft body 15.
is integrally molded, and furthermore, the outer surface of the disk-shaped base (the surface opposite to the shield 17) is provided with a portion that is substantially flush with the outer surface of the end plate 6.

Since the fixed shaft 9 and the shield 17 are integrally molded using a mold and a forging press using a processing method similar to backward extrusion, the part that functions as the shield 17 is can be formed into thin side walls. When performing this molding, it is desirable that the side wall 17a of the shield 17 has a shape in which the inner side is slightly inclined outward with respect to the axis of the fixed shaft body 15. This is because when the integral fixed shaft 9 and shield 17 molded from the mold are removed, they easily come off from the mold. Although it can be removed from the mold even without this inclination, the side wall 17a is deformed when knocked out. Also, from the point of view of its function as a vacuum valve, the shield 17
The purpose is to prevent the diffusion of the arc generated when the electrodes are opened and closed, and the above-mentioned slope of the inner surface does not impair the characteristics of the vacuum valve in any way. Through experiments conducted by the present inventors, it was found that this inclination is preferably about 5° to 10°.

By the way, when the rated voltage is low, the insulation distance is also small, so there is no need to insulate and separate the shield from the fixed shaft. Conventionally, as shown in FIG. It consists of a disk-shaped base 22, and a cylindrical shield 23 drawn by a press is joined to this base 22 by brazing to make it integral. However, since this configuration integrates the fixed shaft 20 and the shield 23 by brazing, it is expected to not only reduce assembly man-hours and the amount of expensive silver brazing material used, but also improve reliability. Can not.

Therefore, in the present invention, as mentioned above, by integrally molding the fixed shaft and the shield using a forging press,
This eliminates the drawbacks of the conventional model.

On the other hand, the entire vacuum valve is assembled by arranging each component as shown in Figure 1, inserting silver solder in the required places, and heating it in a vacuum atmosphere.
Since the disk-shaped base of the fixed shaft is located at the lowest position, the stability of the posture is improved, and even when heated in a vacuum atmosphere, each component maintains a predetermined vertical position, preventing silver solder from flowing out unnecessarily. It is possible to prevent brazing defects from occurring, reduce assembly costs, and improve quality. Furthermore, when a vacuum valve with this configuration is incorporated into a vacuum circuit breaker, the fixed shaft side (lower side in Figure 1) is brought into contact with the insulating frame, and the screw hole provided at the center of the fixed shaft is inserted into the insulating frame side. Secure by screwing in the screws. As a result, the disc-shaped base of the fixed shaft comes into direct contact with the insulating frame, and the disc-shaped base also extends to the inner surface of the end plate, unlike the conventional rod-shaped fixed shaft. Compared to the vacuum valve, the vacuum valve is firmly fixed to the insulating frame. Therefore, no trouble occurs even in response to mechanical external forces during tripping and closing on multiple surfaces, and the operation of the vacuum circuit breaker can be made stable over a long period of time.

[Effect of idea]

Since the present invention is configured as described above,
It is possible to reduce the number of man-hours required for processing and assembly, reduce the amount of brazing material used, lower manufacturing costs, and improve reliability.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of the vacuum valve of the present invention, and FIG. 2 is a sectional view showing an assembly structure of a fixed shaft, fixed electrode, and shield of a conventional vacuum valve. 2... Envelope, 5, 6... End plate, 7... Vacuum container, 8... Fixed electrode, 9... Fixed shaft, 11... Movable electrode, 12... Movable shaft, 17... Shield.

Claims (1)

[Scope of utility model registration request] End plates are provided at both end openings of an envelope formed of an insulating material to form a vacuum container, and one end plate is provided with a fixed shaft having a fixed electrode fixed to the end,
In the vacuum valve, the other end plate has a movable electrode fixed to the end thereof, which is movable via a bellows. A fixed shaft body that is fixed to the fixed shaft body, a substantially disk-shaped base that extends to the other end of the fixed shaft body, and a cylindrical shield that is coaxial with the fixed shaft body and surrounds both electrodes are integrally molded. . A vacuum valve, characterized in that the outer surface of the disc-shaped base is provided with a portion that is substantially flush with the outer surface of the end plate.