JPS62249326A - Vacuum interruptor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a vacuum interrupter, and more particularly to a vacuum interrupter equipped with a longitudinal field generating coil outside a vacuum vessel.

B0 Summary of the invention A vacuum container is formed by joining a metal container to the end of an insulating cylinder by brazing, and a vertical magnetic field generating coil is provided outside the metal container and surrounding a pair of electrodes, and is further insulated from the metal container. In a vacuum interrupter that has a shield inside the vacuum container that covers the joint with the cylinder, the end of the insulating cylinder is connected to the end of the insulating cylinder within the line area connecting the outer peripheral side tip of the coil outside the metal container and the shield tip inside the vacuum container. By configuring the provided metallized layer to be located, electric field concentration in the metallized layer at the solder sealing portion between the insulating cylinder end and the metal member is alleviated, and the withstand voltage characteristics of the external creeping surface of the vacuum interrupter are improved. ◇ C1 Conventional technology Vacuum interrupters generally have metal members hermetically joined to both ends of an insulating tube made of ceramics, glass, etc. by brazing to form a vacuum container. A fixed electrode rod and a movable electrode rod are introduced through the metal member in an airtight manner, and a pair of electrodes is fixed to the inner end of each electrode rod so as to face each other. This vacuum interrupter also has a magnetic field generating coil (
Some devices are equipped with a coil (hereinafter referred to as a coil) to apply a magnetic field (axial magnetic field) parallel to the arc between the electrodes.

An example of such a vacuum interrupter is shown in FIG. 3, and will be described below. 1 is a vacuum container, and the vacuum container 1 includes an insulating cylinder 2 made of ceramics and a metal Jl! sealing one end side (lower end side in the figure) of this insulating cylinder. A metal container made of non-magnetic stainless steel is airtightly joined to the insulating tube by brazing as a metal member that seals the end plate 3 which is a member and the other end side (upper end side) of the insulation @S. It consists of

This metal container Hiroshi has a ceiling plate +a and is formed into a substantially cup shape, and the inside thereof is an arc extinguishing chamber j. A shield 6 made of non-magnetic stainless steel is provided at the lower part of the metal container φ and extends from the metal container side toward the insulating tube side so as to cover the joint between the metal container φ and the insulating tube.

A fixed-side electrode rod having an electrode 11 at its inner end is provided to pass through the ceiling plate μa of the metal container in an airtight manner. Furthermore, an electrode rod t on the movable side having an electrode t at the inner end is provided through the end plate 3 that seals the other end side of the insulating cylinder through a bellows 10 in an airtight and movable manner. It is. The movable electrode rod is provided with a bellows shield saw made of non-magnetic stainless steel like a bellows IO't'lt.

Reference numeral 13 denotes a substantially cylindrical coil, and this coil 13 surrounds the outer periphery of the metal container via the air 11B, and also surrounds a pair of m
It is provided so as to still surround the poles /l and t when cut off. The coil /3 is formed into a cylindrical shape having approximately one turn with a slit at one location, and has an arm /Ja extending radially inward from one end thereof and connected to a fixed electrode rod. 1 is connected to the other end of the arc portion of the coil 130, and tS is a shield provided on the back of the movable electrode t and on the movable electrode rod d.

D0 Problems to be Solved by the Invention In the vacuum interrupter configured as described above, the joint between the insulating tube and the metal container is brazed as shown in FIG. 4, which is an enlarged view of part A in FIG. 3. There is.

That is, an extremely thin metallized layer 16 is formed on the end face of the insulating cylinder, and the end face of the metal container is applied to this metallized layer, and then they are brazed together. Therefore, the metallized layer 16 and the brazing filler metal/? There was a problem in that the presence of a and z7b reduced the withstand voltage characteristics of the external creeping surface of the insulating cylinder.

That is, since the shield 6 covers the inner end of the metallized layer 16 and the brazing material /1& inside the vacuum container 1, the electric field is relatively not concentrated thereon. However, the electric field tends to concentrate on the outer end of the metallized layer L and the brazing material /7b on the outside of the vacuum container L, and since the layer is extremely thin, electrons are easily emitted, causing dielectric breakdown. As a result, there was a problem in that the withstand voltage characteristics of the external creeping surface of the insulating cylinder were deteriorated.

In order to deal with the above-mentioned problem, measures are generally adopted, such as increasing the creepage distance by increasing the dimension 11 of the insulating tube shown in FIG. 3, but this has the problem of increasing costs.

Also, the method shown in Prisoner 5 can be considered. That is, by increasing the dimensions of the shield 2 and increasing the cover distance at the end of the insulating cylinder 2, the distance between the wire connecting the edge of the insulating cylinder 2 and the shield tip 6a, and the horizontal line m passing through the shield tip 6a is increased. ) is set to a sufficiently large angle Iθ, electric field concentration can be prevented and a drop in withstand voltage can be suppressed. However, in this case, it becomes impossible to maintain a sufficient distance g between the shield 6 and the bellows shield /:1, and another problem arises in that the internal withstand voltage of the vacuum incluctor decreases.

Another possible method is the method shown in FIG.

That is, by providing the tip ring 111 of the shield having the same potential as the main metallized layer 16 outside the vacuum interrupter, the electric field concentration in the metallized layer can be alleviated, and the external withstand voltage can be lowered. do not have. However, in this case as well, a shield ring lθ is required, which increases the cost and is disadvantageous.

Means for Solving the E0 Problem The present invention focuses on the fact that a vacuum interrupter is provided with a coil outside the metal container, and uses both the coil and the shield to prevent electric field concentration in the metallized layer portion.

That is, the present invention forms a vacuum container with an insulating tube and a cup-shaped metal container that is brazed to one end of the insulating tube through a metallized layer, and a pair of electrodes that move relatively inside the metal container. A coil with a concave pair of electrodes is provided outside the metal container, one electrode is connected to the metal container and the coil so that they are at the same potential, and a shield covering the metallized layer is placed inside the vacuum container at the same potential as the metal container. A vacuum interrupter is provided at the end of the insulating cylinder so that the metallized layer provided at the end of the insulating cylinder is located within the line area connecting the outer peripheral side tip of the coil outside the metal container and the shield tip inside the vacuum container. Configured.

20 Operation When brazing the end of the insulating tube and the end of the metal container, the metallized layer and brazing material at the joint must be inside the line area connecting the lower end of the shield inside the vacuum container and the lower end of the coil outside the vacuum container. Because of this position, electric field concentration in the metallized layer can be effectively alleviated both inside and outside the vacuum vessel, and in particular, the withstand voltage characteristics of the external creeping surface of the vacuum interrupter are improved.

G. Embodiment The present invention will be described below based on an embodiment shown in FIG. 2 and FIG. 1, which is an enlarged view of section A6 in FIG.

Note that parts equivalent to those in FIG. 3 are given the same reference numerals and their explanations will be omitted.

In FIG. 1, /q is an annular metal fitting made of Cu material provided at the lower end of the metal container. The annular metal fitting 19 is not formed at the end of the insulating cylinder, but is applied to the metallized layer/6 and the brazing material/7 &
, l'lb is fixed.

Therefore, in the present invention, the coil 13 outside the metal container
The metallized Ml group is located within the area of the line (c) connecting the outer peripheral end /Jb on the insulating cylinder side and the tip number & of the shield 6 in the vacuum vessel. As a result, since metal members having the same potential, that is, the shield 6 and the coil 13, are present on both sides of the metallized layer 16, the electric field is not concentrated on the metallized J4j/4 portion.

Note that the lower end of the coil 13 can be curved so that electric field concentration is less likely to occur; however, if the lower end of the coil 3 extends too long, electric field concentration may cause dielectric breakdown. Preferably, it extends to the end of the insulation w1.

H0 Effects of the Invention According to the present invention, the metallized portion at the joint between the end of the insulating tube and the metal container is controlled by the relationship between the shield inside the vacuum container and the coil outside the vacuum container using a magnetic field generating coil. Electric field concentration can be alleviated, the withstand voltage characteristics of the external creeping surface of the vacuum interrupter can be improved, and since a shield ring is not provided as a separate member on the outside of the vacuum vessel, there is no increase in cost.

[Brief explanation of drawings]

FIG. 1 is an enlarged sectional view of the A1 portion in FIG. 2, which is the main part of the present invention, and FIG. 2 is an explanatory diagram of the vacuum interrupter according to the present invention.
Fig. 3 is an explanatory diagram of a conventional vacuum interrupter, Fig. 4 is a detailed view of section A in Fig. 3, and Figs. 5 and 6 are cross-sectional explanatory diagrams showing improved examples of the vacuum interrupter shown in Fig. 3. be. l...Vacuum container, C...Insulating tube, 6...Shield, 6a...Shield tip, q...Electrode rod, 1.
11... Electrode, /3... Coil, 13b... Lower end of coil, 16... Metallized layer. Part 1 Figure 6 --- Shizushi p' 6a --- Seal p first #I 7.9 --- J grade Azusa 8.1l --- Idenki trench -- 13 --- Coil +31 ) - 1 - Coil lower end 16 - - Reed tap 1 Fig. 3

Claims (1)

[Claims] (1) A vacuum container is formed by an insulating cylinder and a metal container brazed to one end of the insulating cylinder via a metallized layer, and a pair of relatively movable electrodes is provided in the metal container, and
A coil that generates a cylindrical axial magnetic field surrounding a pair of electrodes is provided outside the metal container, and one electrode, the metal container, and the coil are connected to the same potential, and the other electrode is connected to the insulating tube through an electrode rod. In a vacuum interrupter constructed by inserting a shield through the metallized layer and providing a shield inside the vacuum container and at the same potential as the metal container so as to cover the metallized layer, the outer peripheral end of the coil outside the metal container and the shield end inside the vacuum container. A vacuum interrupter characterized in that the metallized layer provided at the end of the insulating cylinder is located within the line area connecting the two.