JPH042020A - Manufacture of vacuum interrupter - Google Patents

Abstract

PURPOSE:To effectively prevent evaporating and scattering a low melting point metal so as to give reliable and stable airtight seal uniting to a vacuum interrupter by using an amorphous soldering material made of Cu-Ni-P-Sn as a kind of soldering material. CONSTITUTION:A stationary-side member 1 is composed of a stationary-side end-plate 13 made of Cu and a reed rod 12 made of Cu, and it is unitedly formed by arranging a soldering material made of Cu-Mn-Ni between the respective members to be temporarily assembled. A movableside member 2 is composed of a stationary-side end-plate 23 made of Cu, and a reed rod 22 made of Cu and a bellows 24, and it is unitedly formed by arranging the soldering material made of Cu-Mn-Ni between the respective members to be temporarily assembled. The members 1 and 2 are temporarily assembled together by providing electrodes (components of Cu, Cr and Bi) 11, 21 respectively at the internal-end portions of the respective reed rods 12, 22 via soldering materials 43, 44. The members are temporarily assembled also to an insulating cylinder 3 via respective corresponding soldering-materials 42, 47. Each of these soldering materials belongs to an amorphous soldering material made of 77.6 of Cu-5.7 of Ni-9.7 of Sn(wt.%), and a desired vacuum interrupter can be manufactured by soldering and uniting the members together at a temperature of about 700 deg.C lower than a temperature necessary to solder each of the electrodes, and heating the resultant unit and exhausting the air therefrom.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Industrial Application Field The present invention relates to a method for manufacturing a vacuum interrupter, and particularly to a method for manufacturing a vacuum interrupter whose electrodes contain a low melting point metal.

B1 Summary of the Invention The present invention provides an amorphous brazing part of a vacuum interrupter whose electrodes contain a low-melting point metal, particularly an airtight brazing material in the final assembly stage, which is made of Cu, Ni, P, and Sn. Use brazing material and set the brazing heating temperature to 700℃.
By performing evacuation and brazing at the same time at a temperature below .degree. C., the brazing strength and airtight seal are improved.

C1 Prior Art FIG. 4 is a schematic diagram of a conventional vacuum interrupter of this type.

In the figure, l is a fixed side member, and main members are a lead rod 12 having a fixed electrode 11 at the inner end and a fixed side end plate 13. 2 is a movable member;
The main members are a lead rod 22 having a movable electrode 21 at its inner end, a movable end plate 23, and a bellows 24. 3 is an insulating cylinder made of a member such as ceramics, and 31 is a metal shield provided inside the insulating cylinder.

The vacuum interrupter configured in this way has a movable electrode 21
The electric current is switched on and off by moving up and down in the figure.

A vacuum interrupter having such a configuration is generally manufactured by the following method.

■ As shown in Figure 4, soldering materials 41 to 47 consisting of plate soldering and wire soldering are placed at the joints of each constituent member and temporarily assembled, and this is placed in a vacuum furnace to perform heating exhaust and brazing at the same time. Vacuum interrupters are manufactured in bulk.

■ Part or all of the fixed side member 1 and the movable side member 2 are manufactured in advance in a previous process, and then brazed in a vacuum with a brazing material 42, 47 interposed between them and the insulating cylinder 3. and heating and exhausting at the same time to manufacture a vacuum incretor.

In the case of (2) above, the same brazing material (for example, Cu
In the case of (2), it is common to use brazing materials with different melting points (for example, Cu-based and Ag-based).

B9 Problems to be Solved by the Invention Conventionally, in order to satisfy the various characteristics required of a vacuum interrupter, electrodes were made of Cu (copper) as a main component, and a low melting point metal such as Bi (bismuth) was added to this by 0.1. ~20% by weight
It is common practice to include

However, when the electrode contains such a low melting point metal, it is known that a part of the low melting point metal evaporates from the electrode at the temperature (700 to 1000° C.) during brazing. This evaporated metal not only adheres to the internal materials of the vacuum container, but also partially invades the molten wax material and may adversely affect the brazing joint.

Although the degree of such adverse effects is partly related to the content of low-melting point metals, the hermetic seal joints are particularly problematic.

In other words, even if the mechanical bonding strength is sufficient, there is a risk that the hermetic sealing bond may be insufficient.

Such hermetic seal joints are the brazing metal parts 41, 42, 45, and 46, 47 in Fig. 4 mentioned above.■ When assembling in a vacuum furnace, This applies to all of these brazing metal locations.

■ If the fixed side and movable side members are manufactured in advance in the previous process and then integrated in the next process, the brazing material part 42.47 corresponds to this.

Means for Solving the E0 Problem As a result of various experiments, the inventors first focused on the temperature at which evaporation and scattering of Bi becomes active in metals containing low melting point metals (eg, Bi).

Figure 4 shows 50Cu-40Cr-10Bi (wt%)
The relationship between heating temperature (horizontal axis) and weight loss rate (vertical axis) in a metal member with the composition of inert atmosphere (vacuum)
This is what I investigated.

From this figure, it was found that the weight suddenly decreased from around 700°C, that is, the evaporation and scattering of Bi became active from around 700°C. In other words, it was found that when brazing is performed at a temperature of 700° C. or lower, there is almost no evaporation and scattering of Bi, and there is no adverse effect.

(2) Based on the above (2), we have found that if the brazing material is made of Cu, Ni, P, and Sn and is amorphous and can be brazed at a temperature of 700° C. or lower, stable brazing can be achieved.

If the brazing material is made of Cu, Ni, P, and Sn and is amorphous, it will not only be possible to braze at temperatures below 700°C without evaporation and scattering of Bi, but also Cu-N1-P in the brazed part. It was found that there was a -Sn diffusion layer, which suppressed the intrusion of the low melting point metal into the bonding interface, allowing stable brazing.

Therefore, the present invention provides a brazing material and a brazing method that are not adversely affected even if it contains low-melting point metals. (1) An amorphous material made of Cu, Ni, P, and Sn A brazing material containing 77-80% by weight of Cu and 3% by weight of Ni.
A brazing material made of 8 to 53% by weight, 7 to 8% by weight of P, and 4 to 10% by weight of Sn.

(2) This is a method of brazing at a temperature of 630° C. or higher and at a temperature of 700° C. or lower, at which the evaporation and scattering of the low-melting point metal in the metal member containing the low-melting point metal does not become active.

However, if the proportions of Cu, Ni, P, and Sn or the temperature deviate from the above relationships, a stable brazed joint could not be obtained.

(1) As the low melting point metal, for example, Bi (bismuth)
, Sb (antimony), and other metals that are well known as low melting point metals.

(2) When integrating a vacuum interrupter, (1) A fixed side member and a movable side member are formed separately, and these are integrated with an insulating tube.

■ When one of the fixed side member and the movable side member is integrated with the insulating cylinder in advance, and then the whole is integrated.

Any of the following applies.

(3) The electrode may be brazed to the lead rod in advance in the previous step. Furthermore, in the case of joining an electrode with a low content of low melting point metal and a lead rod, instead of using the In-containing brazing material used in the present invention, Cu-Mn, which is conventionally used for boat fishing, is used.
- It may be a brazing material such as Ni. However, it is desirable to use the brazing material containing In used in the present invention.

(4) In the present invention, the joint portion may be made of Cu;
The entire member does not need to be made of Cu or a material containing Cu as a main component.

Since the brazing temperature for F6 action is approximately 700℃ or less, there is little scattering of low-melting point metals, and since the inside of the vacuum interrupter is not completely sealed during brazing, evaporated low-melting point metals will not be trapped inside the vacuum interrupter. Decrease. Moreover, the existence of a Cu-Ni-P-5n diffusion layer in the brazed joint can suppress the intrusion of low-melting point metals into the joint interface, making it possible to airtightly seal the vacuum incluctor equipped with electrodes containing low-melting point metals. can be made reliably and highly reliable.

G. Example The present invention will be explained in detail based on the following examples.

First, we will explain the results of experiments that investigated the properties of brazing filler metal.

(Experimental Example-1) This is an example of joining a metal member containing a low melting point metal and oxygen-free copper, which is composed of components of 50% by weight of Cu, 40% by weight of Cr, and 10% by weight of Bi.

(a) For a member containing a low melting point metal, approximately 160 g of Cr (chromium) powder with a particle size of 100 mesh is placed in an alumina container (inner diameter 68 mm), and Cu-
Place B1 alloy (approximately 400 g) and cover the container with a lid.
This is degassed and heat treated in a vacuum furnace at a temperature below the melting point of the Cu-B1 alloy to first diffusely bond the Cr particles to form a porous infiltrated base material.

Thereafter, the temperature is raised to infiltrate Cu and Bi into the infiltration base material.

At this time, the inside of the alumina container becomes an atmosphere containing Bi vapor, and a composite metal containing a large amount of Bi is obtained.

The metal material thus obtained is removed from the container and its outer surface is machined into a predetermined size and shape.

(b) About the brazing material 77.6Cu-5,7Ni-7P-9,7Sn (wt%
) Prepare an amorphous wax material.

(c) About brazing The above brazing material (Cu-Ni-P-9n) is
It was placed between the r-B1 alloy member and the member made of oxygen-free copper, placed in an alumina container, and heat-treated in a vacuum furnace (700° C., 15 minutes) to join them.

(d) Results of brazing It was confirmed that the bonded product obtained as described above was firmly bonded, and that the brazing material was sufficiently fluid.

Furthermore, when observing the cross section of the joint using an X-ray microanalyzer, it was confirmed that the diffusion layer of Au and In prevented Bi from precipitating at the interface, forming a stable brazed joint layer. .

(Comparative Experimental Example) For comparison, commonly known 63Ag27Cu
-1 Orno material and Cu-Mn-Ni-based brazing material were used, and the temperature conditions were 800°C for the former and 950°C for the latter, and the other conditions were the same as in the above experiment. However, I couldn't braze it.

(One Example) From the above results, it was found that a brazing material containing Au-In can provide sufficient bonding strength even when directly bonding a Cu (copper) member containing a low melting point metal. A vacuum interrupter shown in FIG. 1 was constructed using this brazing material.

That is, when constructing the vacuum ink club shown in FIG. 1, first, the fixed side member 1 shown in FIG. 2(a) and the movable side member 2 shown in FIG. 2(b) are each formed in a pre-process.

The fixed side member 1 includes an identification side end plate 13 made of Cu (copper),
A lead rod 12 made of Cu, an exhaust pipe 14 made of Cu,
Between each of these members, Cu-M
The n-Ni brazing material is placed and temporarily assembled, and a bond is formed by heating to a temperature of about 980° C. in a non-oxidizing atmosphere (vacuum).

Moreover, the movable side member 2 includes a fixed side end plate 23 made of Cu,
Rulito rod 22 made from Cu, SUS C7° stainless steel @
) made of bellows 24, temporarily assembled by placing Cu-Mn-Ni brazing material between each of these members, and heated to a temperature of approximately 1000°C in a non-oxidizing atmosphere (vacuum). to form a bond.

Fixed side member l and movable side member 2 formed in advance as described above
As shown in FIG. , a component containing 10% by weight of Bi) and temporarily assembled. Also, Cu is added to both ends.
The insulating tube 3 is temporarily assembled to the insulating cylinder 3 provided with auxiliary members 131 and 231 made of copper (copper) via brazing materials 42 and 47 (plate-shaped brazing materials), respectively. These brazing materials 42, 43, 44.47 are 77
．． It is an amorphous brazing material of 6Cu-5,7Ni-7P-9,7Sn (wt%), and in a non-oxidizing atmosphere (vacuum), the electrode brazing material mentioned above has a temperature lower than that of about 70%.
A predetermined vacuum interrupter is integrally constructed by brazing and joining at 0° C., and the desired vacuum interrupter is obtained by heating and exhausting.

In the vacuum interrupter thus formed, the electrode 11.21 and the lead rod 12.22 are joined, and the end plate 1
3.23 and the auxiliary fittings 131, 231 are firmly joined. In particular, the end plate 13.23 and the auxiliary fittings 131, 231
As a result of examining the joint with the helium leak detector using a helium leak detector, it was confirmed that there was no leakage at all.

Note that the Cu-Mn-Ni brazing material that has been commonly used between the bellows, the end plate, and the lead rod was used in the Cu-Ni-P-8n used in the present invention.
This is due to the fact that the brazing properties of the amorphous brazing material are not stable, and the brazing temperature in the post-process is low (there is almost no evaporation and scattering of low melting point metals, and this part of the brazing material is exposed to the adverse effects of Bi. This is because you almost never receive it.

Effects of the H0 Invention Since the brazing material according to the present invention is an amorphous brazing material of Cu-N1-P-5n, the brazing material can be heated at a temperature of 700°C or less, which prevents the evaporation of low-melting point metals. Splashing can be effectively prevented, thereby eliminating the intrusion of low melting point metals into the brazing filler metal. Moreover, the brazing material is C
Since a diffusion layer of u-N1-P-Sn is formed, this diffusion layer can suppress the intrusion of low melting point metal into the bonding interface, so electrodes containing low melting point metal (0.1 to 20% by weight) Even in a vacuum interrupter equipped with a vacuum interrupter, a reliable and stable airtight seal can be achieved.

Further, since the brazing material has a relatively low temperature of about 700° C. or less, the thermal influence on the joining member and other structural members can be reduced.

Therefore, the reliability and durability of the vacuum interrupter can be improved, contributing to quality improvement.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of a vacuum interrupter according to an embodiment of the present invention, FIGS. 2(a) and (b) are partial assembly diagrams of the vacuum interrupter in FIG. 1, and FIG. 3 is a diagram showing heating temperature and FIG. 4, which is a diagram showing the relationship between the weight reduction rate and the weight reduction rate, is a schematic configuration diagram of a conventional vacuum interrupter. 1... Fixed side member, 2... Movable side member, 11...
Fixed electrode, 12... Lead rod, 13... Fixed side end plate, 21... Movable electrode, 22... Lead rod, 23...
- Movable side end plate, 131... Auxiliary member, 231... Auxiliary member. 1st wJ Euse NjI METERU 8゛ Diagram Figure 2 (a) Township #1IIliL area Figure 2 (b) Partial assembly entrance Figure 4 Takenagame

Claims (2)

[Claims] (1) A fixed side member including at least a lead rod and an end plate, a movable side member including at least a lead rod and a bellows, an insulating cylinder to which the end plates of these members are hermetically joined, and each lead rod. A method for manufacturing a vacuum interrupter whose main component is an electrode provided at an inner end, including a first step of forming the fixed side member and the movable side member in advance, and insulating the formed fixed side member and the movable side member. The second step consists of brazing and airtightly joining the tube to the cylinder, and assembling a vacuum interrupter by brazing and joining an electrode to the inner end of each lead rod, and heating and evacuating in a vacuum to obtain a vacuum interrupter. The member is made of a material containing a low melting point metal, and at least the end portion of the member to be the brazed portion in the second step is made of a material containing copper as a main component, and at least the airtight joint portion in the second step is made of a material containing Cu. N
A method for manufacturing a vacuum interrupter, characterized in that an amorphous brazing material made of i, P, and Sn is used, and the brazing heating temperature is 700° C. or less. (2) The method for manufacturing a vacuum interrupter according to claim 1, characterized in that in the first step, at least one of the electrodes is brazed to the inner end of the lead rod.