JPH0541144A - Vacuum interrupter - Google Patents

Abstract

PURPOSE:To facilitate manufacture of a vacuum interrupter using an electrode, which includes the metal having a low melting point, by making flange, in which a ring part and a flange part are unified with step, of phosphor deoxidized copper. CONSTITUTION:A fixed side flange 3, in which a cylindrical ring part 3a and a disc shape flange part 3b are integrated in a stepped shape, and a movable side flange 4, in which a cylindrical ring part 4a and a disc shape flange part 4b are integrated in a stepped shape, are made of phosphor deoxidized copper. Even if the metal having a low melting point, which is sprashed from a fixed electrode 6 and a movable electrode 10 at the time of soldering, intrudes into the flanges 3, 4, it doesn't pass through the flanges 3, 4 along the particle boundary, and through-leak is not generated. Consequently, manufacture of a vacuum interrupter using the electrodes 6, 10, which include the metal having a low melting point, is performed similarly as in the case where an electrode, which does not include the metal having a low melting point, is used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum interrupter in which an electrode contains a low melting point metal such as bismuth (hereinafter referred to as Bi).

[0002]

2. Description of the Related Art An example of a typical structure of a vacuum interrupter is shown in FIG. The vacuum container 1 is composed of an insulating cylinder 2 made of ceramics or the like, and a fixed flange 3 and a movable flange 4 made of copper which are connected to both ends of the insulating cylinder 2. The fixed-side flange 3 is formed integrally by connecting a cylindrical ring portion 3a and a disc-shaped flange portion 3b in a stepwise manner, and the movable-side flange 4 is formed as a cylindrical ring portion 4a and a disc. The flange portion 4b is formed integrally by being connected stepwise. In the figure, 3c and 4c are stepped connecting portions.

A fixed lead rod 5 penetrates and is fixed to the central portion of the flange portion 3b of the fixed side flange 3. The fixed electrode 6 is attached to the tip of the fixed lead rod 5 in the vacuum container 1.
Is attached.

On the other hand, the flange portion 4b of the movable side flange 4
A hole 7 is formed in the central part of the above, through which a movable lead rod 8 is inserted into the vacuum container 1, and a movable electrode 10 facing the fixed electrode 6 is attached to the tip thereof. The movable lead rod 8 and the flange portion 4b of the movable side flange 4 are connected by a bellows 11, and the movable lead rod 8 is movable in the axial direction.

An operating mechanism (not shown) is connected to the movable lead rod 8, and the movable lead rod 8 is operated by the operating mechanism.
Is moved in the axial direction, the electrodes 6 and 10 are opened and closed.

Such a vacuum interrupter is manufactured by brazing in a vacuum furnace. The decrease in the strength of the joint portion (the brazing joint portion between the metallized portion of the insulating cylinder 2 and the rings 3a, 4a) due to the influence of the residual stress due to the brazing is caused by
It is relieved by the fact that it is integrated with 4b and is connected by a stepwise connecting portion.

[0007]

By the way, in such a vacuum interrupter, in order to obtain a low breaking current value characteristic and a low surge voltage characteristic, Bi, Pb, Zn,
A low melting point metal such as Sn, Sb, Se or Te is contained.

However, when a vacuum interrupter in which the electrode contains a low melting point metal such as Bi is manufactured by brazing,
The low-melting-point metal component in the electrode scatters during brazing, causing a problem that it leaks through the copper flanges 3 and 4, making manufacture of the vacuum interrupter very difficult.

Oxygen-free copper is conventionally used as the material for the flanges 3 and 4, and the flanges 3 made of oxygen-free copper are used.
FIG. 2 shows the results of examining the probability of penetration leak when a vacuum interrupter was manufactured with the thicknesses of 4 being 1 mm, 2 mm, 3 mm, and 4 mm. As the material of the electrode, Cu-C
A brazing temperature was set to 650 ° C. using an r-Bi alloy.

As can be seen from FIG. 2, when the thickness of the flanges 3 and 4 is increased, the occurrence of penetrating leak is reduced, and when it is 4 mm, it almost disappears.

However, the thickness of the flanges 3 and 4 is 4
mm, the strength of the brazed portion between the ring portions 3a and 4a and the metallized portion of the ceramic insulating cylinder 2 becomes extremely low due to the effect of residual stress, as shown in FIG. turn into.

[0012]

In order to solve the above problems, according to the present invention, an insulating cylinder and a cylindrical ring portion and a disk-shaped flange portion, which are attached to one end of the insulating cylinder, are connected stepwise. And a fixed side flange integrally formed with the other end of the insulating cylinder, and a movable side integrally formed by connecting a cylindrical ring portion and a disc-shaped flange portion stepwise. The fixed lead rod that penetrates the flange, the flange portion of the fixed side flange, the fixed electrode that is attached to the tip of the fixed lead rod, contains the low melting point metal, and is guided into the insulating cylinder through the flange portion of the movable side flange. A vacuum interrupter comprising a movable lead rod, a movable electrode provided at the tip of the movable lead rod so as to face the fixed electrode, and containing a melting point metal, and a bellows connecting the movable lead rod and the movable side flange. Oite, wherein the fixed-side flange and a movable-side flange is to that the phosphorus deoxidized copper.

[0013]

[Function] Since the fixed side flange and the movable side flange are made of phosphorus deoxidized copper, even if the low melting point metal scattered during brazing enters the flange, it does not penetrate.
There is no leak.

[0014]

EXAMPLE An example of the present invention will be described. The constituent members are the same as those shown in FIG.
No. 4 is not made of oxygen-free copper but made of phosphorus-deoxidized copper.

In order to investigate the cause of the through leak, the cross section of the flanges 3 and 4 after the brazing process of the vacuum interrupter using the conventional flange made of oxygen-free copper was analyzed, and a micrograph thereof was conceptually shown. As shown in Fig. 4, it was found that the crystal grains of copper increased due to the heat load during brazing. Since the low melting point metal Bi infiltrates along the grain boundaries of copper, it is presumed that the infiltrated Bi penetrates the flange and the voids generated thereby cause the leak.

Therefore, in the present invention, as described above, the material of the integral fixed and movable flanges 3 and 4 is changed from oxygen-free copper to phosphorus-deoxidized copper. FIG. 5 is a conceptual representation of a micrograph of a cross section of the flanges 3 and 4 of the vacuum interrupter manufactured by using phosphorous deoxidized copper as the material of the flanges 3 and 4.
Shown in. As shown in this figure, the crystal grains of copper do not increase even by the heat load during brazing. This is because a small amount of phosphorus is present in phosphorus-deoxidized copper, and this phosphorus suppresses the growth of copper crystal grains.

Therefore, even if Bi, which is a low melting point metal, penetrates into the flanges 3 and 4, it does not penetrate through the flanges 3 and 4 along the grain boundaries, and as shown in FIG. If the thickness of 4 is 2 mm, the through leak does not occur. Moreover, if the thickness is 2 mm, as shown in FIG. 3, proper brazing strength can be maintained. The results shown in FIGS. 2 and 3 are obtained by brazing at 650 ° C. using an electrode made of Cu—Cr—Bi.

[0018]

According to the vacuum interrupter of the present invention, the material of the flange integrally formed by connecting the ring portion and the flange portion stepwise is phosphorus deoxidized copper. Even if the low melting point metal penetrates, the crystal grain boundaries of copper do not increase even by the heat load of 1. and the penetration of the flange is blocked and the penetration leak does not occur. Therefore, it becomes possible to manufacture the vacuum interrupter using the electrode containing the low melting point metal in the same manner as that using the electrode containing no low melting point metal.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a typical vacuum interrupter.

FIG. 2 is a graph showing a relationship between a flange thickness and a probability of occurrence of a through leak.

FIG. 3 is a graph showing the relationship between flange thickness and brazing strength.

FIG. 4 is a view conceptually showing a micrograph of a cross section of an oxygen-free copper flange after brazing.

FIG. 5 is a view conceptually showing a micrograph of a cross section of a phosphor deoxidized copper flange after brazing.

[Explanation of symbols]

 1 Vacuum container 2 Insulation cylinder 3 Fixed side flange 3a Ring part 3b Flange part 3c Connecting part 4 Movable side flange 4a Ring part 4b Flange part 4c Connecting part 5 Fixed lead rod 6 Fixed electrode 8 Movable lead rod 10 Movable electrode 11 Bellows

Claims (1)

[Claims] 1. An insulating cylinder, an insulating cylinder, a fixed side flange attached to one end of the insulating cylinder and integrally formed by connecting a cylindrical ring portion and a disk-shaped flange portion in a stepwise manner, A movable side flange attached to the other end of the fixed side flange, which is integrally formed by connecting a cylindrical ring part and a disc-shaped flange part in a stepwise manner, and a fixed lead rod penetrating the flange part of the fixed side flange. , A fixed electrode attached to the tip of the fixed lead rod and containing a low melting point metal, a movable lead rod guided into the insulating cylinder through the flange part of the movable side flange, and the fixed electrode at the tip of the movable lead rod. In a vacuum interrupter, which is provided to face each other and includes a movable electrode containing a low melting point metal, and a bellows that connects the movable lead rod and the movable side flange, the fixed side flange and the movable side flange are connected to each other. A vacuum interrupter characterized by being made of deoxidized copper.