JPH042019A - Manufacture of vacuum interrupter - Google Patents

Abstract

PURPOSE:To effectively prevent the volatilization and scatter of a low fusion point metal so as to manufacture a vacuum interrupter of reliable and stable airtight seal union by having a soldering material made of Cu, Ni, P and Sn, and also having it formed in an amorphous body. CONSTITUTION:A stationary-side member 1 is made up of a stationary-side end-plate 13, a reed bar 12 and an exhaust pipe 14 all made of Cu, and it is unitedly formed by arranging a soldering material between their respective members to be temporarily assembled. A movable-side member 2 is made up of a stationary-side end plate 23 made of Cu, a reed bar 22 made of Cu and a bellows 24, and it is unitedly formed by arranging the soldering material between their 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 inner-end portions of their respective reed bars 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 is made of 77.6 of Cu-5.7 of Ni-7 of P-9.7 of Sn (wt.%) and is amorphous, and a desired vacuum interrupter can be obtained by soldering and uniting the members together at a temperature of about 700 deg.C lower than a soldering temperature, and heating the resultant unit while making the inside of the unit vacuous to exhaust the air via the exhaust pipe 14.

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.

B8 Summary of the Invention The present invention uses an amorphous brazing material made of Cu, Ni, P, and Sn in the joint part as an airtight brazing material in the final assembly stage of a vacuum interrupter whose electrodes contain a low melting point metal. In addition, by setting the brazing heating temperature to 700° C. or lower and evacuating after assembly, the brazing strength and airtight joint are improved.

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

In the figure, reference numeral 1 denotes a fixed side member, and the main members are a lead rod 12 having a fixed electrode 11 at its inner end and a fixed side end plate 3. 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 ink cleaners are manufactured in bulk.

■ As shown in Fig. 4, soldering materials 41 to 47 made of sheet soldering and wire soldering are placed at the joints of each constituent member 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).

■ The fixed side member 1 and the movable side member 2 are manufactured in advance in the previous process, and the brazing material 42.47 is placed between the insulating cylinder 3 and the insulating cylinder 3.
Brazing is performed in a vacuum with the help of 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.

D Problems to be Solved by the Invention Conventionally, in order to satisfy the various characteristics required for vacuum interrupters, low melting point metals such as Bi (bismuth) have been used for electrodes.
It is generally practiced to contain 0.1 to 20% by weight.

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 during brazing (700 to 100° C.). This evaporated metal not only adheres to the internal materials of the vacuum container, but also partially intrudes into the melted wax material, which poses 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.

For such an airtight seal joint, the brazing metal parts 41, 42, 45, 46, and 47 in Figure 4 of the fat description are the corresponding parts, and ■ When assembling all at once in a vacuum furnace This applies to all of these brazing metal locations. Moreover, in the case of bulk brazing in a vacuum, the vacuum ink tank becomes completely airtight under high-temperature heating, which causes the problem that evaporated B1 tends to stay 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.

As a result of various experiments, the inventors focused on the temperature at which evaporation and scattering of B1 becomes active in a metal containing a low melting point metal (eg, Bi).

Figure 3 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 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 soldering can be achieved.

If the brazing material is made of Cu, Ni, P, and Sn and is amorphous, not only can brazing be performed at temperatures below 700°C without evaporation and scattering of Bi, but also Cu-Nj-P- It was found that the presence of a 8n diffusion layer suppressed the intrusion of the low melting point metal into the bonding interface and enabled stable brazing.

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

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. A high-quality brazing material containing 77 to 80% by weight of Cu, 38 to 53% by weight of Ni, 7 to 8% by weight of P, and 4 to 1% of S and n.
A brazing material made of 0% by weight.

(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 CuNNl%P, Sn, or 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) 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.

(4) The electrode may be brazed to the lead rod in advance in the previous step. In addition, in the case of joining with an electrode rod containing a small amount of low melting point metal, instead of using the In-containing brazing material used in the present invention, Cu-Mn-Ni, which is conventionally used for boat fishing, is used.
There is no problem even if it is a brazing material such as. However, it is desirable to use the brazing material containing In used in the present invention.

(5) 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 F1 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 presence of the Cu-N1-P-5n diffusion layer in the brazed joint can suppress the intrusion of low-melting point metals into the joint interface.
To ensure reliable and highly reliable hermetic sealing of a vacuum interrupter equipped with an electrode containing a low melting point metal.

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 copper, which is composed of 50% by weight of Cu, 40% by weight of Or, 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 powder is placed on top of the Cr powder.
- B1 alloy (approximately 400 g) is placed, the container is covered with a lid, and this is degassed in a vacuum furnace and heat treated at a temperature below the melting point of the Cu-B1 alloy to first diffuse bond the Cr particles. to form 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) 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-5n) is
It was placed between the r-B1 alloy member and the member made of oxygen-free copper, placed in an alumina container, and bonded by heat treatment (700° 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 Ag, Cu, and In prevented Bi from precipitating at the interface, forming a stable brazed joint layer. It was done.

(Comparative Experimental Example) For comparison, commonly known 63Ag27Cu
-10 Ino material and Cu-Mn-Ni brazing material were used, and the temperature conditions were 80°C for the former and 950°C for the latter, and the other conditions were the same as in the above experimental example. It peeled off and could not be brazed.

(One example) From the above results, it is clear that sufficient bonding strength can be obtained even if Cu (copper) members containing low melting point metals are directly bonded using an amorphous brazing material of Cu-N1-P-Sn. Since this was found, the 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 11 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),
It consists of a lead rod 12 made of Cu and an exhaust pipe 14 made of Cu. A brazing material (plate-like brazing material, linear axle material) is placed between these parts for temporary assembly, and non-oxidized The bond is formed by heating to a temperature of about 1000° C. in a neutral atmosphere (vacuum).

Moreover, the movable side member 2 includes a fixed side end plate 23 made of Cu,
It consists of a bellows 24 made of a lead rod 22.5US (stainless steel) made of Cu, and a brazing material is placed between each of these parts to temporarily assemble it and heat it in a non-oxidizing atmosphere (vacuum) for about 1,000 yen. The bond is formed by heating to a temperature of °C.

Note that the above-mentioned brazing material used was a Cu-MnNi brazing material.

Fixed side member 1 and movable side member 2 formed in advance as described above
As shown in FIG. , Bi is 10
% by weight) and temporarily assemble. Also, C at both ends.
It is temporarily assembled to the insulating cylinder 3 provided with auxiliary members 131 and 231 made of u (copper) via brazing materials 42 and 47 (plate-shaped brazing materials), respectively. These brazing materials 42.43.44.47 are 7
7.6Cu-5,7Ni-7P-9,7Sn (wt%)
The solder metal is amorphous and is bonded in a non-oxidizing atmosphere (vacuum) at a temperature of approximately 700°C lower than the temperature of the solder metal used in the previous process to form a predetermined vacuum interrupter, and then heated. At the same time, the vacuum is evacuated through the exhaust pipe 14, and the desired vacuum interrupter is obtained by 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 an investigation using a helium leak detector confirmed that there was no leakage at all.

H0 Effects of the Invention Since the brazing material according to the present invention is made of Cu, Ni, P, and Sn and is amorphous, the heating temperature of the brazing material is 7.
Since it can be carried out at a temperature of 00° C. or lower, it is possible to effectively prevent the low melting point metal from evaporating and scattering, thereby eliminating the intrusion of the low melting point metal into the brazing material. Moreover, the brazing material has Cu in the part.
- Since a diffusion layer of -N1-PSn is formed, this diffusion layer can suppress the intrusion of low melting point metal into the bonding interface. Even in a vacuum interrupter, airtight sealing can be achieved reliably and stably.

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.

Furthermore, after the vacuum interrupter is integrated with the brazing material, it is evacuated through an exhaust pipe to obtain the desired vacuum interrupter, so the inside of the vacuum interrupter component is not completely sealed during brazing, so evaporated Bi It is possible to reduce the amount of metals such as those trapped inside, making the airtight 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. 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, 14... Exhaust pipe, 21... Movable electrode, 22... Lead rod, 23... Movable side end plate, 131-... Auxiliary member, 2
31... Auxiliary member. Figure 1 Jisami no 11■416゛Diagram 2 (a) Setsubun#flYukuni-gun ImashimafL map

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 the formed fixed side member and the movable side member. A second step of assembling a vacuum interrupter by brazing and joining the members and the insulating cylinder and an electrode to the inner end of each lead rod, and a second 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 the end portion of the member to be brazed in the second step is formed of a copper material, and at least the airtight joint in the second step is Cu and N in the part
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. (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; The third step consists of joining and brazing an electrode to the inner end of each lead rod to form a vacuum interrupter, and the fourth step consists 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 to be brazed in the third step is formed of a copper material, and Cu and N are added to at least the airtight joint in the third step.
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. (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.
The method for manufacturing the vacuum interrupter described in Section 1.