JPH03190022A - Manufacture of vacuum interrupter - Google Patents

Abstract

PURPOSE:To prevent a metal, having a low melting point, from intruding into the junction interface and to stabilize brazing, by using the brazing material, which is made of Ti-Al alloy including a specified quantity of Ti, for airtight seal junction of members in which electrodes including the metal having a low melting point are provided. CONSTITUTION:In a fixed side member 1 and a movable side member 2 formed previously, electrodes 11, 21 made of copper members including the metal having a low melting point are temporarily assembled at inner ends of lead bars 12, 22 through brazing materials 43, 44. An insulating cylinder 3, in which both ends auxiliary members 131, 231 made of copper are provided, is temporarily assembled through brazing materials 42, 47. The brazing materials 42, 43, 44, 47 are made of Ti-Al alloy including Ti at 20-90weight%, and they are brazed at a predetermined temperature in the non-oxidizing atmosphere for junction, and a vacuum service branch pipe 14 is pinched off through an exhaust pipe 14 to obtain a desirable vacuum interrupter. The metal having a low melting point is thereby prevented from intruding into the junction interface to secure and stabilize the airtight seal junction.

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.

B9 Summary of the Invention The present invention provides a method for applying Ti- to the hermetic brazing part in the final assembly stage of a vacuum interrupter whose electrodes contain a low melting point metal.
By using a brazing material containing Al as a main component and vacuuming after assembly, the brazing strength and airtightness are improved.

C8 Prior Art FIG. 4 is a schematic diagram of a conventional vacuum interrupter of this type.

In the figure, violet is a fixed side member, and the main members are a linear rod 12 having a fixed electrode II at its 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 2I at its inner end, a movable end plate 23, and a bellows 24. , 3 is an insulating cylinder made of a material such as ceramics, and 3! is a metal shield provided inside the insulating tube.

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 Fig. 4, soldering materials 41 to 47 made 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.

■ As shown in Figure 4, brazing materials 41 to 47 made of sheet solder and wire solder are placed at the joints of each component and temporarily assembled, and then brazed in a non-oxidizing atmosphere (for example, hydrogen atmosphere). After that, the vacuum interrupter is manufactured by heating and exhausting in the atmosphere through an exhaust pipe (not shown).

(2) The fixed side member 1 and the movable side member 2 are manufactured in advance in a pre-process, and brazing materials 42 and 47 are interposed between them and the insulating cylinder 3, and they are brazed together in a vacuum. Alternatively, a vacuum interrupter is manufactured by vacuuming after brazing.

In addition, in the cases of (1) and (2) above, the same brazing material (for example, Cu-based brazing material) is placed in each location, and in the case of (2), brazing materials with different melting points (for example, Cu-based and Ag-based brazing material) are used. is common.

D9 Problems to be Solved by the Invention Conventionally, in order to satisfy the various characteristics required for vacuum interrupters, it has generally been the case that electrodes contain 0.1 to 20% by weight of a low melting point metal, such as Bi (bismuth). It is being done.

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 penetrates into the molten brazing material, causing a problem of adversely affecting 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. This applies to all of these brazing metal locations. Moreover, in the case of batch brazing in a vacuum, the inside of the vacuum interrupter becomes completely hermetically sealed under the high temperature heating state, so there is a problem that evaporated Bi tends to be trapped inside, further deteriorating the airtight joint characteristics.

■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 found that if Cu (copper) members are joined together using a brazing material made of Ti and AI, a low melting point metal will be added to the brazed part. It has been found that airtight brazing can be achieved without any intrusion. In other words, it has been found that a reliable hermetic seal joint can be achieved by using Ti--Al brazing material for the hermetic seal joint portion of the vacuum interrupter. It has also been found that by adding a material that forms a eutectic with Ti or AI, the diffusion layer of Ti and AI can be stabilized and the bonding can be made more reliable.

In other words, it was found that the existence of a Ti or AI diffusion layer in the brazing portion effectively prevents low-melting point metals from entering the bonding interface and enables stable brazing.

Furthermore, it has been found that the -layer hermetic seal bonding characteristics are stable if the vacuum interrupter is not manufactured all at once in a vacuum, but is manufactured by brazing and then evacuating (evacuating).

Therefore, in the present invention, a Ti-Al alloy brazing material containing 20 to 90% by weight of Ti is used as a brazing material for an airtight seal joint when integrating a vacuum interrupter.

Note that (1) a third component consisting of a material that forms a eutectic with either Ti or AI is added, the total content of Ti and AI is 20% by weight or more, and the weight ratio is Ti/AI=20/ 80
An alloy brazing material having a ratio of ~90/10 may also be used. Examples of the material (third component) that forms this eutectic include Cu (copper), I
At least one of n (indium), Ni (nickel), Mn (manganese), and Fe (iron) is applicable.

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

(3) The conditions for using the brazing material are as follows: ■The temperature of the wax material is 900-1000℃.

■The atmosphere for brazing metal is vacuum or inert gas.

■The thickness of the brazing material is 0.02 to 1, OIII.

It is preferable that

(4) When integrating a vacuum interrupter, ■ When a fixed side member and a movable side member are formed separately, and when these are integrated with an insulating tube. ■ When one of the fixed side member and movable side member and an insulating tube are formed If you integrate them in advance and then integrate them as a whole.

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 the Tf-AI brazing material used in the present invention, a conventionally commonly used brazing material such as Cu-Mn-Ni can be used. It's okay to have one. However, it is desirable to use the TiAl brazing material used in the present invention.

(6) In the present invention, the joint portion only needs to be made of Cu, and the entire member does not need to be made of Cu or a material containing Cu as a main component.

Since the inside of the vacuum interrupter is not completely sealed during F0 action brazing, it is less likely that evaporated metals such as Bi are trapped inside, and moreover, there is no Ti in the brazed joint.

The presence of the AI diffusion layer can effectively prevent low-melting point metals from entering the bonding interface, ensuring reliable and highly reliable hermetic sealing of vacuum interrupters equipped with electrodes containing low-melting point metals. Can be done.

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

(a) For parts containing low melting point metals: Approximately 160g of Cr (chromium) powder with a particle size of I00 mesh is placed in an alumina container (inner diameter 68u), and Cu-B
1 alloy (approximately 400 g) was placed, the container was covered with a lid, and this was degassed in a vacuum furnace and heat treated at a temperature below the melting point of the Cu-B1 alloy to first diffusely bond the Cr particles. Forms a porous infiltration matrix.

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) Tf and AI powders with a particle size of 325 mesh and these T
i, Cu powder (-3
25 mesh) is prepared and mixed so that Ti is 35% by weight, AI is 30% by weight, and Cu is 35% by weight.

This mixed powder is heated and melted in a non-oxidizing atmosphere, and the obtained ingot is rolled and processed into a foil-shaped brazing material of about 0.2 x m.

(C) About brazing The above brazing material (T i -A I-Cu) is
- A B4 alloy member and a member made of oxygen-free copper were placed between each other, placed in an alumina container, and covered with a lid, and heat-treated in a vacuum furnace (980° C., 15 minutes) to bond 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 Ti and AI prevented Bi from precipitating at the interface, forming a stable brazed joint layer. .

(Experimental Examples 2 to 38) Under the same conditions as in Experimental Example 1 described above, brazing joints were investigated by changing the components of the brazing material. The results were as shown in Figure 3 and the table below.

(The following is a blank space) In addition, in Experimental Examples 30 to 35 and 37 and 38, the bonding strength was good, and as a result of the tensile test, it was not the brazed portion but the bonded base material portion that broke.

Therefore, from these results, (1) the brazing material is formed of Ti and AI, and the component ratio (weight ratio) of both is T i /
It was found that AI should be set to 20/80 to 90/10.

■When adding a third component that forms eutectic with Ti and AI, Ti
It was found that the upper limit of the content is 80% by weight, which has the effect of stabilizing the diffusion layer of AI.

■The preferred composition is a material that forms a eutectic with Ti and AI (tertiary
component), and the component ratio (weight ratio) is Ti /AI = 40/60 to 80/20 (Ti + A
I)/(Third component) It was found that it is sufficient to deviate from -20/80 to 90/10.

(Comparative Experimental Example) For comparison, commonly known AgCu-1n brazing filler metal and Cu-Mn-Ni brazing filler metal were used, and the temperature conditions were 800°C for the former and 950°C for the latter. In addition, brazing was attempted under the same conditions as in Example-1 above, but
Both peeled off and could not be brazed.

(One Example) From the above results, Ti- containing 20 to 90% by weight of Ti
It was found that A1 alloy brazing material can provide sufficient bonding strength even when directly bonding Cu (copper) components containing low melting point metals, so this brazing material was used to create the vacuum interrupter shown in Figure 1. was configured.

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, 35Cu-3
A brazing material (plate brazing material, linear brazing material) consisting of 5Ti-30AI (wt%) is arranged and temporarily assembled, and heated to a temperature of approximately 980°C in a non-oxidizing atmosphere (vacuum). to form a bond.

Moreover, the movable side member 2 includes a fixed side end plate 23 made of Cu,
It consists of a bellows 24 made of lead rod 22.5US (stainless steel) made of Cu, and a Cu-Mn-Ni brazing material is placed between each of these members to temporarily assemble it in a non-oxidizing atmosphere (vacuum). The bond is formed by heating to a temperature of about 100° C. (middle).

Fixed side member formed in advance as described above! and movable side member 2
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) via brazing materials 42 and 47 (plate-shaped brazing materials), respectively.

These brazing materials are 74Cu-13Ti-13AI (wt%) (Experiment Example-37), and they are brazed and bonded in a non-oxidizing atmosphere (vacuum) at a temperature of about 920°C, which is lower than the brazing temperature mentioned above. A predetermined vacuum interrupter is integrally constructed using the above-mentioned method, and then the desired vacuum interrupter is obtained by heating and evacuation by evacuation through the exhaust pipe 14, and pinching off the exhaust pipe 14.

The end plates 13, 23 and the auxiliary fittings 131, 231 in the vacuum interrupter thus formed were firmly joined, and as a result of investigation using a helium leak detector, it was confirmed that there was no leakage at all.

The reason for using the conventionally commonly used Cu-Mn-Ni brazing material between the bellows, lead rod, and end plate is that SUS brazing is stable with CuTi-Al in the present invention. This is because when the movable side member 2 is configured as described above, this brazing material portion is hardly affected by the adverse effects of Bi.

H. Effects of the Invention Since the present invention uses a brazing filler metal mainly composed of Ti and AI, a diffusion layer of Tf and AI is formed in the brazed part, and this diffusion layer forms a bonding interface between low melting point metals. Contains low-melting point metals (0,1-2
Even in a vacuum interrupter equipped with an electrode that is 0% by weight), a reliable and stable hermetic seal joint can be achieved.

Moreover, by adding a metal material that forms a eutectic with Ti and AI, the brazing joint can be performed more stably.

Furthermore, since the vacuum interrupter is integrated by brazing and then evacuated through an exhaust pipe to obtain the desired vacuum interrupter, the inside of the vacuum interrupter component is not completely sealed during brazing, so evaporated Bi, etc. This reduces the amount of metal trapped inside, making the hermetic seal joint more reliable and stable.

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 (b) are partial assembly diagrams of the vacuum interrupter in FIG. 1, and FIG. FIG. 4, which is an explanatory diagram of the component ratio and evaluation in each example, is a schematic configuration diagram of a conventional vacuum interrupter. 1... Fixed side member, 2... Movable side member, 12.22
... Lead rod, 42, 43, 44.47... Brazing material. Figure 2 (0) Gunbunhyoritatsu Gunbunkotachi 18

Claims (4)

[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, and an insulating cylinder in which the end plates of these members are hermetically joined;
A method for manufacturing a vacuum interrupter whose main component is an electrode provided at the inner end of each lead rod, comprising: a first step of forming the fixed side member and the movable side member; and a first step of forming the fixed side member and the movable side member. A second step of assembling a vacuum interrupter by brazing and joining the member and the insulating cylinder and an electrode to the inner end of the lead rod, and a third step of evacuating the inside of the assembled vacuum interrupter to obtain a vacuum interrupter. The electrode is formed of a material containing a low melting point metal, at least an end portion of the member to be brazed in the second step is formed of a copper material, and at least the airtight joint portion in the second step is formed of a material containing a low melting point metal. Ti-Al containing 20 to 90% by weight of Ti
A method for manufacturing a vacuum interrupter characterized by using a brazing material whose main component is. (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. (3) 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, and an insulating cylinder in which the end plates of these members are hermetically joined;
A method for manufacturing a vacuum interrupter whose main component is an electrode provided at the inner end of each lead rod, comprising: a first step of forming either the fixed side member or the movable side member; and the fixed side member. or a second step of brazing the other member of the movable side member to one end of the insulating tube, and brazing the other end of the insulating tube to the member obtained in the first step; It consists of a third step of joining and brazing and joining an electrode to the inner end of the lead rod to form a vacuum interrupter, and a fourth step of evacuating the inside of the vacuum container of the assembled vacuum interrupter to obtain a vacuum interrupter. The electrode is formed of a material containing a low melting point metal, at least the end portion of the member that will be the brazed portion in the third step is formed of a copper material, and at least the airtight joint portion in the third step is coated with 20 to 20% Ti. Ti-Al containing 90% by weight
A method for manufacturing a vacuum interrupter characterized by using a brazing material whose main component is. (4) Claim 3 characterized in that at least one of the electrodes is brazed to the inner end of the lead rod in the first step and the second step.
A method for manufacturing a vacuum interrupter described in .