JPH0467523A - Manufacture of vacuum interrupter - Google Patents

Abstract

PURPOSE:To prevent a low-melting point metal from infiltrating and diffusing into an airtight brazed section by butting the surfaces of electrodes containing the low-melting point metal, and providing a filter at the portion to be brazed. CONSTITUTION:A fixed electrode 6 is coupled at the tip of a fixed lead bar 5, and a moving electrode 9 is coupled at the tip of a moving lead bar 8 via a brazing filler metal respectively. The brazing filler metal is inserted into a junction 22 between a fixed side flange 2 and a metal ring 1b end. A force is applied to the lead bar 8, the surface 6c of the electrode 6 and the surface 9c of the electrode 9 are butted, exposed portions of the electrodes themselves are reduced, and the inside of the portion 22 is covered by a filter 21. It is heated in a vacuum furnace, and the electrode 6 and the lead bar 5, the electrode 9 and the lead bar 8, and the flange 2 and the metal ring 1b are brazed respectively. The electrodes 6, 9 have little exposed portion, and the evaporated and scattered quantity of Bi is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for manufacturing a vacuum interrupter whose electrodes contain a low melting point metal such as bismuth (hereinafter referred to as Bi).

B. Summary of the Invention The method for manufacturing a vacuum interrupter according to the present invention comprises: abutting the surfaces of electrodes containing a low melting point metal; and providing a cylindrical filter inside the part to be brazed to form an airtight seal. In this state, brazing is performed in a vacuum. Since there is little exposed part of the electrode, there is little evaporation of the low melting point metal. Also, vaporized low-melting point metals are captured by the filter, so they do not enter the airtight braze.

C. Prior Art One type of vacuum interrupter that suppresses surge voltage is one in which the electrode contains a low melting point metal such as Bi. The structure of an example of such a vacuum interrupter is shown in FIG.

In FIG. 5, reference numeral 1 denotes an insulating container, which consists of an insulating cylinder 1a made of glass or ceramics and metal rings 1b and lc attached to both sides of the insulating cylinder 1a. Insulation capacity! ! A fixed side flange 2 and a movable side flange 3 are attached to the ends of #1 metal rings 1b and lc. A fixed lead rod 5 passes through the center of the fixed flange 2. The fixed lead rod 5 is integrated with the fixed flange 2. A fixed M pole 6 is attached to the tip of the fixed lead rod 5 within the insulating container 1 .

A hole 7 is provided in the center of the movable flange 3, through which a movable lead rod 8 is inserted into the insulating container 1. A movable electrode 9 facing the fixed electrode 6 is attached to the tip of the movable lead rod 8. These fixed electrodes 6 and movable electrodes 9 are made of a conductive material such as ml (411 lower, Cu) as a base material, and contain a low melting point metal such as Bi.

There is a bellows 1 between the movable lead rod 8 and the movable side flange 3.
The movable lead rod 8 is connected to an operating mechanism (not shown), and the electrodes 6 and 9 are opened and closed by moving the movable lead rod 8 in the axial direction by the operating mechanism.

Note that an arc shield 11 surrounding the electrodes 6 and 9 is provided within the insulating container 1. Moreover, 12 in the figure is an exhaust pipe provided on the fixed side flange 2.

Such a vacuum interrupter is manufactured by the following procedure.

First, fixed lead rod 5, fixed side flange 2, fixed electrode 6
, while brazing the exhaust pipe 12, the movable lead rod 8
, the bellows 10, the movable electrode 9, and the movable flange 3 are brazed.

Brazing is carried out in vacuum, in an inert gas or a reducing gas.

Next, the metal rings 1b and lc at both ends of the insulating container 1, the fixed side flange 2, and the movable side flange 3 are welded.

Next, the inside of the insulating container 1 is evacuated through the exhaust pipe 12, and then the exhaust pipe 12 is collapsed to close the container.

D Problems to be Solved by the Invention As described above, manufacturing a vacuum interrupter whose electrodes contain a low melting point metal requires brazing, welding, and vacuum evacuation, making the manufacturing process complicated and costly. It was also accompanied by

On the other hand, in general vacuum interrupters that are not low-surge types, all structural members are joined by brazing in a vacuum, so brazing can sometimes involve evacuation of the inside of the container, simplifying the manufacturing process. I can figure it out.

The reason why the above-mentioned simple manufacturing method cannot be used for vacuum interrupters whose electrodes contain a low melting point metal such as Bi is as follows.

First, when brazing electrodes in a vacuum, low melting point metals such as Bi, which are electrode components, evaporate and scatter at high temperatures (currently used brazing materials are heated to over 750°C), resulting in a low cutting current. One reason is that the value cannot be obtained.

Second, the evaporated and scattered Bi acid component during vacuum brazing penetrates and diffuses into the parts, making vacuum-tight brazing impossible.

E. Means for Solving the Problems In order to solve the above problems, the present invention provides an insulating container, a fixed flange and a movable flange attached to both ends of the insulating container, a fixed lead rod passing through the fixed flange, and a fixed lead. a fixed electrode attached to the tip of the rod and containing a low-melting point metal, a movable lead rod guided into the insulated cavity through the movable flange, and provided at the tip of the movable lead rod opposite to the fixed electrode, A method for manufacturing a vacuum interrupter comprising a movable electrode containing a low melting point metal and a bellows connecting the movable lead rod and the movable side flange, the movable lead rod, the bellows and the movable side flange, or in addition to the movable lead rod and the movable side flange, an insulating A step of brazing the container, a step of brazing the fixed lead rod and the fixed side flange, or an insulating container in addition to these, and abutting the surfaces of the electrodes together, and a step of brazing the insulating container and the fixed side flange or the movable side flange. A vacuum interrupter is manufactured by a step of providing a cylindrical filter inside the part to be brazed, and brazing the electrode, lead rod, insulating container, and fixed side flange or movable side flange in vacuum in this state. That's what I did.

F. Effect Since the surfaces of the electrodes containing the low melting point metal are brought into contact with each other and brazing is performed, evaporation of the low melting point metal is reduced. Additionally, since a filter is provided, airtight brazing can prevent low melting point metals from entering and diffusing into the parts.

Embodiment G Next, a method for manufacturing a vacuum interrupter according to the present invention will be explained based on an embodiment shown in the drawings.

First, as shown in FIG. 1(a), the movable lead rod 8 and one end of the bellows 10, the other end of the bellows 10 and the inner edge of the movable flange 3, and the outer edge of the movable flange 3 and the insulating container 1.
The movable side assembly 13 is manufactured by brazing the metal ring IC end of the .

At the same time, as shown in FIG. A cylindrical filter 21 is fixed on the inner bottom surface of the filter by brazing or the like.This filter 21 is a permeable metal with pores, and is made of sintered metal such as nickel (N1)-chromium (Cr)Ni. reactor.

Note that the metal ring 1b of the insulation capacitance N1 should not be made a part of the movable assembly 13 but a part of the fixed assembly 14.
The end may be brazed to the outer edge of the fixed flange 2.

Next, the fixed electrode 6 and the fixed lead rod 5, the movable electrode 9 and the movable lead rod 8, and the metal ring 1 of the insulating container 1 of the movable assembly 13.
The b end and the outer edge of the fixed side flange 2 of the fixed side assembly 14 are brazed.

The electrodes 6 and 9 are made of C to ensure low breaking current value characteristics.
It is based on a conductive material such as U and contains a low melting point metal such as Bi. In addition to Cu, the conductive materials that form the electrodes 6 and 9 include 11 (Ag),
Cu alloy, Ag alloy, etc. are used, and these include
Alloys of Cr, cobalt (Co), Ni, iron (Fe), molybdenum (Mo), tungsten (W), tantalum (Ta), etc., as well as alloys of MO compounds, W compounds, etc. are also used. be done. The low melting point metals contained in these materials are not limited to Bi, but also PB (PB).
, tellurium (Tea), antimony (SB), etc. should also be adopted.

In the final assembly, first, with the fixed side assembly 14 facing down, the back surface 6b of the fixed electrode 6 is fitted to the tip of the fixed lead rod 5 via a brazing material. On the other hand, the back surface 9b of the movable electrode 9 is fitted to the tip of the movable lead rod 8 of the movable side assembly 13 via a brazing material.

In this state, the movable assembly 13 is assembled by covering the stationary assembly 14.

That is, the end of the insulating cylindrical metal ring 1b of the movable assembly 13 is placed on the outer edge of the fixed flange 2 of the fixed assembly 14. A brazing material is interposed at a seam (brazed portion) 22 between the fixed side flange 2 and the end of the metal ring 1b.

Next, a downward force is applied to the movable lead rod 8, and the fixed electrode 6
The surface 6c of the movable electrode 9 and the surface 9c of the movable electrode 9 are brought into contact with each other.

As a result, the surfaces 6c and 9c of the electrodes 6 and 9 are covered with each other, and the exposed portion of the electrodes themselves is reduced. Moreover, the filter 21 on the inner bottom surface of the fixed side flange 2 is
As shown in the figure and FIG. 3, the inner side of the part 22 to be brazed, which is the joint between the stationary side flange 2 and the metal ring 1b, is covered.

After assembling as described above, the inside of the container consisting of the insulating container 1, both flanges 2.3, and the bellows 10 is evacuated by evacuation in a vacuum furnace, and the fixed electrode 6 is heated. The fixed lead rod 5, the movable electrode 9 and the movable lead rod 8, and the fixed side flange 2 and the metal ring 1b are brazed, respectively. Since the exposed portions of the electrodes 6 and 9 are small, the amount of Bi evaporation and scattering due to heating during brazing is reduced.

FIG. 4 shows the relationship between temperature and Bi evaporation amount for brazing. It can be seen that the amount of Bi evaporated is significantly reduced by the method of the present invention (indicated by a solid line) compared to the conventional method (indicated by a broken line) in which the electrode surfaces are not brought into contact with each other.

On the other hand, the part 22 to be airtightly brazed is the filter 2.
1, the evaporated and scattered Bi is captured by this filter 21 and prevented from entering and diffusing into the brazing portion 22.

Therefore, the vacuum tightness of the brazed portion 22 is maintained,
Its reliability is extremely high.

Note that it is conceivable to provide a metal shield such as stainless steel or a ceramic shield instead of the filter 21, but these cannot sufficiently capture Bi due to their small surface area.

■ Effects of the Invention According to the method for manufacturing a vacuum interrupter according to the present invention, since brazing is performed with the surfaces of the electrodes butted against each other, the exposed surface of the electrodes is reduced, and the low melting point metal contained in the electrodes is reduced. Evaporation and scattering are reduced.

In addition, a filter was installed inside the part to be vacuum-tightly brazed to capture the evaporated low melting point metal.
Brazing can prevent low-melting point metals from entering the part, and as a result, brazing can maintain the vacuum tightness of the part and has extremely high reliability.

3 is the movable side flange, 5 is a fixed lead rod, 6 is a fixed electrode, 8 (: movable lead rod, 91, a movable electrode; 101, f bellows, 21ba filter, 22 Rose brazing is part.

[Brief explanation of drawings]

Figure 1 (al) is a sectional view showing the assembly process of the movable part and fixed part, Figure 2 is a sectional view showing the final assembly process,
2 is a partial sectional view of FIG. 2, FIG. 4 is a diagram showing the relationship between temperature and bismuth evaporation amount for brazing, and FIG. 5 is a sectional view showing the structure of an example of a vacuum interrupter. In the drawing, 1 is an insulating container, lb and lc are metal rings, 2 is a fixed side flange, Patent Application Co., Ltd.

Claims (1)

[Claims] An insulating container, a fixed flange and a movable flange attached to both ends thereof, a fixed lead rod passing through the fixed flange, a fixed electrode containing a low melting point metal attached to the tip of the fixed lead rod, and a movable side flange. A movable lead rod guided into an insulating container through a flange, a movable electrode provided at the tip of the movable lead rod opposite to the fixed electrode and containing a low melting point metal, and between the movable lead rod and the movable flange. A method for manufacturing a vacuum interrupter comprising a bellows connecting a movable lead rod, a bellows and a movable flange, or a step of brazing an insulating container in addition to the movable lead rod, a bellows and a movable flange, and a step of brazing an insulating container to a fixed lead rod and a fixed flange, or in addition to these. In the step of brazing the insulating container, the surfaces of the electrodes are butted together, and a cylindrical filter is provided inside the part to be brazed between the insulating container and the fixed side flange or the movable side flange, and in this state, the electrodes are A method for manufacturing a vacuum interrupter, comprising the steps of: and brazing the lead rod, the insulating container, and the fixed side flange or the movable side flange in a vacuum.