JPH042011A - Manufacturer of vacuum interrupter - Google Patents

Abstract

PURPOSE:To prevent evaporation and splash of low melting point metal effectively, and to confirm and stabilize airtight seal jointing by using a wax material consisting of Au-In as main component. CONSTITUTION:Fixed side member 1 consists of a fixed side end plate 13 and a lead rod 12, both made of Cu. Wax material of Cu-Mn-Ni is positioned between respective members tentatively assembled, and jointly formed. A movable side member 2 consists of a fixed side end plate 23, a lead rod 22 and a bellows 24, which are made of Cu. Wax material of Cu-Mn-Ni is positioned between respective members tentatively assembled members laud 2 are tentatively assembled to be joined in formation by providing electrodes (components of Cu, Cr, Bi) 11, 12, on the inner of each lead rod 12 and 22, through wax materials 43, 44. Also they are tentatively assembled to insulated cylinder 3 through each of wax materials 42, 47. Those wax materials are braze jointed at approx. 500 deg.C, lower than electrode brazing temperature with 67Au-33In (by weight%), after which heated and exhausted to gain desired vacuum interrupter.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application 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.

B6 Summary of the Invention The present invention uses a brazing material mainly composed of Au-In in the brazing part of a vacuum interrupter whose electrodes contain a low melting point metal, especially in the airtight brazing material in the final assembly stage.
In addition, by setting the brazing temperature to 700° C. or lower and performing evacuation and brazing assembly at the same time, the brazing strength and airtight joint are improved.

C8 Prior Art FIG. 5 is a schematic diagram of a conventional vacuum interrupter of this type.

In the figure, ■ is a stationary side member, which is composed of a lead rod 12 having a stationary electrode 11 at its inner end and a stationary side end plate 13 as main members. 2 is a movable side 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 5, 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 pre-process, and then brazed in a vacuum with a brazing material 42, 47 interposed between them and the insulating cylinder 3. A vacuum interrupter is manufactured by simultaneously performing heating and evacuation.

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).

D0 Problems to be Solved by the Invention Conventionally, in order to satisfy the various characteristics required for vacuum interrupters, 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 material of the vacuum container, but also partially enters the molten brazing 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, 46, and 47 in Fig. 5 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 Problem E1 As a result of various experiments, the inventors first focused on the temperature at which evaporation and scattering of Bi becomes active in a metal containing a low melting point metal (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), it has been found that if Au--In is used as a brazing material that can be brazed at a temperature of 700° C. or lower, stable brazing bonding can be achieved.

In other words, if the brazing material is made of A'u-In, not only can brazing be performed at a temperature of 700° C. or lower without evaporating and scattering of Bi, but also a diffusion layer of AuIn exists in the brazing part.
It was found that this made it possible to suppress the intrusion of the low melting point metal into the bonding interface and ensure stable brazing.

Therefore, the present invention uses a brazing material having a composition range shown in FIG. 3 as a brazing material for bonding Cu members together in a vacuum interrupter, namely: (1) ■ A brazing material containing 21 to 36% by weight of Au and In. .

■ A brazing material made of 38-53% by weight of Au and In.

(2) A temperature of 500°C or higher, which is the temperature above the eutectic point of Au and In, and 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. This is a method of brazing.

However, if the proportions of Au and In 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) Copper is a metal containing a low melting point metal.

Metals with high conductivity such as copper alloys, silver, and silver alloys 9 fall under this category.

(3) It is preferable to mix powders of each component in predetermined amounts and process the brazing material into a predetermined shape so that the characteristics of each component can be utilized.

Further, the desired brazing material is formed by compression molding into a ring shape or a disk shape using a mold. Alternatively, it can be easily obtained by first compression molding into a plate shape and then using a laser or the like.

Alternatively, an organic binder may be mixed with the mixed powder to form a paste and then applied. In addition, the powder is -
A particle size of 100 mesh or less (149 μm or less) is preferable.

(4) 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 cylinder.

■ 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.

(5) 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.

(6) 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 F1 action brazing temperature may be about 700° C. or lower, there is little scattering of the low melting point metal, and the intrusion of the low melting point metal into the brazed portion is reduced. Moreover, the existence of a diffusion layer of Au and In in the brazed joint can suppress the intrusion of low-melting point metals into the joint interface, ensuring airtight sealing of vacuum interrupters equipped with electrodes containing low-melting point metals. It can be made highly reliable.

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

First, we will explain the results of an experiment 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) For the brazing material, prepare Au and In powders with a particle size of 325 mesh,
Thoroughly mix 53 g of U and 27 g of In using a mixer.

Approximately 1.5 g was collected from the obtained mixed powder, and the diameter was 40 m.
The mixture was uniformly filled into a mold of 300 m in diameter and press-molded at 30 tons to obtain a circular thin molded product with a thickness of about 0.4 mm.

(c) About brazing The brazing material (Au-In) is placed between the Cu-Cr-B1 alloy member and the member made of oxygen-free copper, and these are placed in an alumina container and the lid is closed. Then, they were bonded by heat treatment (500° C., 15 minutes) in a vacuum furnace.

(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. .

(Other Experimental Examples) Under the same conditions as in Experimental Example 1 above, brazing joints were investigated by changing the components of the brazing material. The results showed that within the composition range shown in FIG. 3, results similar to those in the above case could be obtained. That is, it was found that (1) the brazing material should be formed of Au-In, and the In content should be 21 to 36% by weight and 38 to 53% by weight.

(Comparative Experimental Example) For comparison, commonly known 63Af27Cu
-101n brazing material and Cu-Mn-Ni 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 Experimental Example I above, but brazing was attempted, but peeling occurred. 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 interrupter 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 l includes a fixed 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,
Lead rod 22.5US (stainless steel) made of Cu
It consists of a bellows 24 manufactured by Manufacturer Co., Ltd., and is temporarily assembled by placing Cu-Mn-Ni brazing material between each of these members, and heated to a temperature of about 1000°C in a non-oxidizing atmosphere (vacuum). Heat 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. In addition, Cu is added to both ends.
Each insulating tube 3 is equipped with a brazing material 42. Temporarily assemble using '47 (plate-shaped brazing material). These brazing materials 42, 43, 44, 47 are 6
7Au-331n (wt%), and in a non-oxidizing atmosphere (vacuum), the above-mentioned electrode brazing material is joined at a temperature of about 500° C., which is lower than the temperature, to integrally constitute a predetermined vacuum interrupter. The desired vacuum interrupter is obtained by heating and evacuation.

In the vacuum interrupter thus formed, the electrodes 11.21 and the lead rods 12, 22 are joined, and the end plate 1
323 and the auxiliary fittings 131, 231 are firmly joined. In particular, the joints between the end plates 13, 23 and the auxiliary fittings 131, 231 were investigated using a helium leak detector, and 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 is different from the brazing material containing AuIn used in the present invention. This is because the properties are not stable, and the temperature of the brazing material in the subsequent process is low and there is almost no evaporation and scattering of low melting point metals, so this brazing material is hardly affected by the negative effects of Bi. be.

H1 Effects of the Invention Since the brazing material according to the present invention has AuIn as its main component, the brazing material can be heated at a temperature of 700° C. or lower, which effectively prevents the evaporation and scattering of low-melting point metals. This prevents low melting point metals from entering the brazing material. Moreover, since a diffusion layer of Au and In is formed in the soldering part, this diffusion layer can suppress the intrusion of low melting point metals into the bonding interface.
Even in a vacuum interrupter equipped with an electrode that is 0% by weight), a reliable and stable hermetic seal joint 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 drawings]

FIG. 1 is a schematic configuration diagram of a vacuum interrupter according to an embodiment of the present invention, FIGS. 2(a) and 2(b) are partial assembly diagrams of the vacuum interrupter in FIG. FIG. 4 is a diagram showing the relationship between heating temperature and weight reduction rate, and FIG. 5 is a schematic 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, 2I... Movable electrode, 22... Lead rod, 23...
- Movable side end plate, 131... Auxiliary member, 231... Auxiliary member. Figure 1 M of #11, approximately 118 Figure 3 A clear diagram of the composition range of the Rose 7 Ze of the present invention 1 Heavy! ('/,) n Figure 2 (a) W) Partial Euro Partial Rough Fl Prisoner Figure 5 Tsuyoshi Bundle Double ζ Intauba's Nail Strategy

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 formed of a material containing copper as a main component, and at least the airtight joint portion in the second step is made of Au- I
A method for manufacturing a vacuum interrupter, characterized in that a brazing material containing n as a main component 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.