JP2000182485A - Manufacture of vacuum value - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a valve capable of forming a covering layer, having uniform quality in a connecting part by piling up a brazing material of silver or tin, or containing silver or tin as main component on a conductor connecting surface of an current-carrying shaft, heating at a specified temperature to melt the brazing material, and forming the covering layer of the brazing material on the conductor connecting surface. SOLUTION: A circular brazing material disk 9 of silver or tin, or containing silver or tin as a main component, having the same diameter as that of a fixed side current- carrying shaft 2A is placed on the top of the fixed side current-carrying shaft 2A. The outer diameter of the brazing material disk 9 is the same as that of the fixed side current-carrying shaft 2A, the brazing material disk 9 has a specified thickness, and is made of BAg-8 alloy (72 wt.% Ag and 28 wt.% Cu). In this state, with the temperature raised to a specified value in a heating furnace, a 10-14 μm thick silver covering film is formed in a connecting part 14A of the tip of the fixed side current- carrying shaft 2A. The brazing material of silver or tin, or containing silver or tin as a main component is piled up on the conductor connecting surface of the current- carrying shaft 2A, heated to 700-830 deg.C to cause the brazing material to melt, and the covering film of the brazing material is formed on the conductor connecting surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing a vacuum valve.

[0002]

2. Description of the Related Art FIG. 5 is a longitudinal sectional view showing an example of a conventional vacuum valve, showing an open state. In FIG.
The lower end of an insulating container 3A made of ceramic and cylindrical is brazed to the upper end of an intermediate flange 4b made of stainless steel in an annular shape, and the lower end of the intermediate flange 4b is made of a support made of stainless steel. A ring 4a is brazed, and the support ring 4a has an upper intermediate flange 4b.
The same intermediate flange 4c is brazed symmetrically.

[0003] The lower end of the intermediate flange 4c is brazed to the upper end of the same insulating container 3B as the upper insulating container 3a, and the upper end of the upper insulating container 3A is fixed to the fixed side end made of stainless steel. The lower end surface of the outer periphery of the plate 5A is brazed, and the upper end of the movable side end plate 5B is also symmetrically brazed to the lower end of the lower insulating container 3B.

[0004] The lower end of an upper arc shield 6A made of stainless steel is inserted into the inner periphery of the support ring 4a and brazed to the upper side of the stepped portion of the intermediate portion. The upper end of a short lower arc shield 6b, also made of stainless steel, is inserted into the lower side and brazed.

[0005] In a through hole formed at the center of the fixed end plate 5A, a fixed energizing shaft 2A made of a copper rod is penetrated with its upper end slightly protruding therefrom and brazed to the fixed end plate 5A. ing. Similarly, a movable-side conducting shaft 2B made of a copper rod is also provided through a bush 5b in a through hole formed at the center of the movable-side end plate 5B.

A fixed electrode 1A is brazed to the lower end of the upper fixed energizing shaft 2A, and the movable end of the same product as the fixed electrode 1A is mounted to the upper end of the lower movable energizing shaft 2B. Electrode 1B is symmetrically brazed.

A lower end of a bellows 7 made of a stainless steel plate in a bellows shape is brazed to an inner surface of the movable side end plate 5B, and a lower surface of a stepped portion formed at an intermediate upper portion of the movable side conductive shaft 2B is brazed. The bellows cover 8 is brazed, and the upper end of the bellows 7 is brazed to the lower surface of the bellows cover 8.

In the vacuum valve constructed as described above, the final assembly is performed in a high-temperature vacuum furnace, and an insulating rod (not shown) connected to the lower end of the movable-side energized shaft 2B is provided with an operating mechanism of the vacuum circuit breaker. As a result, the movable-side energized shaft 2B is driven upward as shown by the arrow A, and the movable-side electrode 1B brazed to the upper end of the movable-side energized shaft 2B is fixed to the fixed-side electrode 1A. Upon contact, the vacuum circuit breaker is turned on.

Conversely, from this closed state, the movable-side conducting shaft 2B
Is driven downward, the movable electrode 1B is separated from the fixed electrode 1A, and the vacuum circuit breaker is in an open state. At this time, the arc generated between the fixed side electrode 1A and the movable side electrode 1B is extinguished inside the vacuum maintained state,
The particles of the metal vapor scattered by the arc adhere to the inner surfaces of the upper arc shield 6A and the lower arc shield 6B, thereby preventing the surface creeping insulation properties of the inner circumference of the insulating containers 3A and 3B from being deteriorated.

FIG. 6 is a view showing a state in which the vacuum valve is connected to a conductor of an insulating frame of a vacuum circuit breaker. In FIG. 6, the lower surface of the fixed-side connection conductor 13 is fixed to the connection portion 14A at the upper end of the fixed-side energized shaft 2A with bolts, and the outer connection portion 14B at the lower end of the movable-side energized shaft 2B has an annular shape. Conductor 15
Is inserted and brazed. On the right side of the conductor 15, the upper end of a flexible conductor 16 formed by laminating a thin mild steel plate is connected with a bolt, and the lower portion of the flexible conductor 16 is connected to a movable connection conductor. 17
Are connected by bolts.

Accordingly, the upper end surface of the fixed-side energized shaft 2A is plated with silver or tin to reduce the contact resistance at the time of connection with the fixed-side connection conductor 13, and the outer periphery of the lower portion of the movable-side energized shaft 2B as well. Also, silver plating and tin plating are applied.

That is, in this method of manufacturing a vacuum valve, as a partial assembly, a fixed-side conducting shaft 2A and a fixed-side end plate 5A in which a fixed-side electrode 1A plated with silver or tin is brazed to a connecting portion 14A are brazed. Similarly, the movable-side conducting shaft 2B to which the movable-side electrode 1B is brazed, the movable-side end plate 5B, and the bellows 7
And the bellows cover 8 is brazed with a high melting point brazing material.

Next, the partially assembled fixed side and movable side, the upper and lower insulating containers 3A and 3B, and the intermediate sealing part 4 therebetween are hermetically sealed using a low-temperature brazing material in a vacuum furnace. And final assembly. The upper and lower connection surfaces 14A, 14B
May be formed after the above high-temperature brazing.

[0014]

However, in such a conventional method of manufacturing a vacuum valve, in the high melting point brazing of the partial assembly, the connection portion at the upper end of the fixed side conducting shaft 2A is used.
There is a possibility that not only a part of the silver or tin plating coating layer applied to the connection portion 14B on the outer periphery of the lower end of the movable side conductive shaft 2B and 14A is softened, but also evaporated and thinned to vary the thickness.

If the coating layer becomes excessively thin, the connection between the fixed-side connecting conductor 13 at the upper end and the conductor 15 at the lower end brazed to the ends of the fixed-side conducting shaft 2A and the movable-side conducting shaft 2B. The resistance may vary, and the temperature rise due to energization may exceed an allowable value.

For this reason, a method of increasing the plating thickness of silver and tin is conceivable. However, the time required for electroplating is greatly increased, and the required energy is increased. Further, it is conceivable to cover the outer surface of the plating layer with ceramic or other metal to prevent the temperature of the plating layer from rising, thereby preventing softening due to high-temperature partial assembly. However, this requires more steps.

On the other hand, a method of forming a plating layer after the final assembly is also conceivable. However, there is a possibility that other metal portions may be corroded during the plating process. It takes time. Therefore, an object of the present invention is to provide a method of manufacturing a vacuum valve capable of forming a coating layer of constant quality on a connection portion without increasing the number of steps.

[0018]

According to a first aspect of the present invention, silver or tin or a brazing material containing silver or tin as a main component is laminated on a conductor connection surface of a current-carrying shaft of a vacuum valve.
It is characterized in that it is heated and melted at 830 ° C. to form a brazing material coating on the conductor connection surface.

The invention corresponding to claim 2 is characterized in that the heating and melting of the brazing material are performed simultaneously with the vacuum high-temperature brazing of the vacuum valve. The invention corresponding to claim 3 is characterized in that the thickness of the coating is at least 1 μm or more. By such means, in the present invention, a single coating forming step for reducing the contact resistance with respect to the current-carrying shaft at the stage before assembling is omitted.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the method for manufacturing a vacuum valve according to the present invention will be described below with reference to the drawings. FIG.
FIG. 5 is a partial longitudinal sectional view showing a first embodiment of a method of manufacturing a vacuum valve according to the present invention, which corresponds to a partially enlarged view of FIG. 5 shown in the prior art, and corresponds to claims 1 and 2. is there.

FIG. 1 is a partially exploded view of the final assembly process in the vacuum furnace of the vacuum valve shown in FIG. That is,
A brazing material (not shown) is placed on the upper end of the insulating container 3A in the same manner as in the related art, and a fixed-side end plate 5A brazed to the fixed-side current-carrying shaft 2A by partial assembly on the brazing material is conventionally provided. Are mounted on the same axis. In this state, brazing is performed in a high-temperature vacuum furnace (820 to 830 ° C.) in the final assembly.

On the other hand, in the present invention, silver or tin having the same diameter as this fixed-side energized shaft 2A or an annular solder containing silver or tin as a main component is provided on the upper end surface of the fixed-side energized shaft 2A. The material disk 9 is placed as shown by the arrow. The outer diameter of the brazing disk 9 is the same as the outer diameter of the fixed-side conducting shaft 2A.

Further, a ceramic weight 10 having a convex portion 10a formed at the center of the lower surface is successively placed on the upper surface of the brazing material disk 9. The outer diameter of the weight 10 is the outer diameter of the fixed-side energized shaft 2A + 2 mm.

At the center of the connecting portion 14A at the upper end of the fixed-side energized shaft 2A, a female screw 2a is machined.
A hole having the same diameter as the inner diameter of the brazing material disk 9 is machined, and the outer diameter of the convex portion 10a of the weight 10 is slightly smaller than the inner diameter of the female screw 2a.

The thickness of the brazing disc 9 first adopted by the inventors is 0.04 mm, and the material is BAg-8 (72% by weight of Ag, C
u28% by weight) alloy. The weight of the weight 10 is 500 g
It is.

In this state, the temperature is raised to 790 ° C. in a heating furnace, and a silver coating having a thickness of 10 to 14 μm is applied to the connection surface 14A at the upper end of the fixed-side energized shaft 2A without performing electrolytic plating with a plating solution.
Could be formed.

According to this method of manufacturing a vacuum valve, electrolytic plating can be omitted, so that not only the process can be shortened, but also energy saving can be achieved and the problem of plating solution treatment can be solved. it can.

In the above embodiment, the brazing material disc 9
Has the same outer diameter as the outer diameter of the fixed-side energized shaft 2A.
Depending on the positioning accuracy of the brazing disk 9 by 10, it may be slightly increased to prevent the silver coating layer from dropping on the outer peripheral portion of the connection surface 14 </ b> A.

In the above embodiment, the material of the brazing disk 9 is a BAg-8 alloy. However, the ratio of silver to copper may be changed, or only silver may be used, and tin or tin may be contained. Brazing material may be used.

Further, in the above-described embodiment, the brazing material coating layer formed on the connection surface 14A is formed after the final assembly of the vacuum valve, but may be performed simultaneously with the final assembly in a high-temperature vacuum furnace.
In this case, the process can be further reduced.

According to the results of the trial production performed by the inventors, when the coating layer was formed simultaneously with the final assembly using the above-described BAg-8 alloy, the surface roughness was improved to Ra: 0.9 to 1.05. When the thickness of the coating was less than 1 μm, the underlying copper was partially exposed. When the thickness was 1 μm or more, not only the coating was not exposed, but also the adhesiveness was excellent and it did not peel off.

FIG. 2 is a partially enlarged exploded longitudinal sectional view showing a method of forming a coating layer of a brazing material on the connection surface 14B on the outer periphery of the lower end of the movable-side energized shaft 2B, corresponding to FIG. It is. FIG. 3 is an assembled view of the exploded view of FIG.

In FIG. 2 and FIG. 3, the movable side conductive shaft 2B
A pair of tightening jigs 11 each having an L-shaped cross section in FIG. 2 and a substantially Ω-shape in FIG. 3 are inserted from below into the inner circumference of the lower end of the tightening jig 11. A pair of semicircular brazing filler metals 12 having a thickness of 0.04 mm is inserted in advance.

In this state, as shown in FIG. 3, a pair of fastening jigs 11 are tightened with bolts, and the temperature is raised and heated in the same manner as in the embodiment shown in FIG. 1 to form a silver coating layer or a tin-containing alloy coating layer. Can be formed.

FIG. 4 is a graph showing an appropriate relationship between the thickness of the brazing material containing silver as a main component and the silver content obtained by experiments by the inventors. The curve shown in FIG. 4 indicates that the thickness of the brazing material of the alloy containing silver as a main component is T (mm) and the silver content (% by weight).
Indicates that a good silver alloy coating can be formed in the range of T ≧ 2.16 ° A. That is, the mark “試 験” indicates the test conditions when a good coating was formed, and the mark “X” indicates the test conditions in which copper of the current-carrying shaft of the base material partially appeared in the coating.

[0036]

As described above, according to the first aspect of the present invention, silver or tin or a brazing material containing silver or tin as a main component is overlaid on the conductor connection surface of the energizing shaft of the vacuum valve.
By heating and melting at 830 ° C. to form a coating of the brazing material on the conductor connection surface, in particular, according to the invention corresponding to claim 2, the heating and melting of the brazing material are performed by a vacuum high-temperature brazing assembly process of a vacuum valve. Simultaneously, since a single coating forming step for the energized shaft in a state before assembly is omitted, a method of manufacturing a vacuum valve capable of forming a constant quality coating layer on the connection portion without increasing the number of steps is obtained. Can be. .

According to the third aspect of the present invention,
When the thickness of the coating is at least 1 μm or more, it is possible to obtain a method of manufacturing a vacuum valve having excellent coating adhesion.

[Brief description of the drawings]

FIG. 1 is a partially exploded longitudinal sectional view showing a first embodiment of a method for manufacturing a vacuum valve of the present invention.

FIG. 2 is a partially exploded vertical sectional view showing a second embodiment of the method for manufacturing a vacuum valve of the present invention.

FIG. 3 is a partial plan view showing a second embodiment of the method for manufacturing a vacuum valve of the present invention.

FIG. 4 is a graph showing the operation of the vacuum valve of the present invention.

FIG. 5 is a longitudinal sectional view showing an example of a conventional vacuum valve.

FIG. 6 is a diagram showing an example of a state in which a conventional vacuum valve is incorporated.

[Explanation of symbols]

1A: fixed-side electrode, 1B: movable-side electrode, 2A: fixed-side conducting shaft, 2B: movable-side conducting shaft, 3A, 3B: insulating container, 4
... intermediate sealing parts, 5A ... fixed side end plate, 5B ... movable side end plate, 6A ... upper arc shield, 6B ... lower arc shield, 7 ... bellows, 8 ... bellows cover, 9 ... brazing disk, 10 ... Weight, 10a: convex portion, 11: fastening jig, 12: brazing material, 13: fixed connection conductor, 14A, 14B: connection portion, 15: conductor, 16: flexible conductor, 17: movable connection conductor.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hiromichi Somei 1 Toshiba-cho, Fuchu-shi, Tokyo Inside the Fuchu factory, Toshiba Corporation

Claims (3)

[Claims] 1. A brazing material containing silver or tin or silver or tin as a main component is superimposed on a conductor connecting surface of a current-carrying shaft of a vacuum valve, and heated and melted at 700 ° C. to 830 ° C. to form a brazing material on the conductor connecting surface. A method for manufacturing a vacuum valve for forming a coating. 2. The method of manufacturing a vacuum valve according to claim 1, wherein the heating and melting of the brazing material are performed simultaneously with a step of assembling the vacuum valve with a high-temperature vacuum. 3. The method according to claim 1, wherein the thickness of the coating is at least 1 μm.