JPH0455398Y2 - - Google Patents

Description

[Detailed description of the invention] A. Industrial application field The present invention relates to a vacuum interrupter, and in particular, a brazing material layer is provided on the inside of the metal end plate joined to the metal bellows at the part that comes into contact with the atmosphere to improve rust prevention. Relating to an enhanced vacuum interrupter.

B. Summary of the invention When one end of a metal bellows is joined to the inside of a metal end plate that constitutes a part of a vacuum vessel, a The brazing metal layer provides anti-rust properties,
It is intended to improve the durability and reliability of a vacuum interrupter by strengthening the rust prevention ability in areas where it is difficult to prevent rust by painting.

C. Prior Art A vacuum interrupter constitutes the main part of a vacuum circuit breaker, and together with its driving device, it is very important.

The second diagram representing the schematic structure of such a vacuum interrupter
As shown in the figure, electrodes 13 and 14 are integrally provided on opposing inner end surfaces of a pair of lead rods 11 and 12 that are in a straight line with each other, respectively. One lead rod 11 is integrally fixed to the metal end plate 16 while passing through the metal end plate joined to one end of the insulating tube 15 . The other lead rod 12, which is connected to a drive device (not shown), is connected via a metal bellows 18 to a metal end plate 17 joined to the other end of the insulating tube 15.
The electrode 14 is capable of reciprocating in the opposite direction of the electrodes 14 and can come into contact with the electrode 13 on the fixed side. Then, an electrode 1 held by an end plate 16 is placed in a vacuum chamber 19 in an insulating cylinder 15 kept in a vacuum.
A shield 20 surrounding the electrodes 3 and 14 is incorporated.
This prevents metal vapor constituting the electrodes 13 and 14 from adhering to the inner wall of the insulating cylinder 15 due to the arc generated when the electrodes 3 and 14 approach each other, thereby preventing insulation failure from occurring.

Incidentally, ceramics such as alumina or borosilicate-based hard glass are used as the insulating tube 15, but the metal end plates 16 and 17 to be joined to this are made of metal with a coefficient of thermal expansion similar to that of the insulating tube 15. ,
For example, iron-based alloys such as Fe-Ni alloy and Fe-Ni-Co alloy are often used.

D Problems to be solved by the invention As shown in Fig. 3, which shows the part where the metal bellows and the metal end plate are joined in the vacuum interrupter shown in Fig. 2, one end (upper end) is on the movable side. The other end (lower end side) of the metal bellows 18 that is joined to the lead rod 12 is brazed to an annular metal bellows joint 21 provided on the end plate 17 so as to protrude inward.

Generally, the above metal end plate 17 is used as the metal end plate 17.
Iron-based alloys such as Fe-Ni alloys are prone to rust, so
A coating film 2 is applied to the part of the metal end plate 17 that is exposed to the atmosphere.
Anti-corrosion treatment has been carried out by grade 2.

However, the end face 23 facing the vacuum chamber 19 on the radially inner side of the bellows joint 21 (hereinafter this part will be referred to as the inner end face) has a small gap with the lead rod 13. Therefore, it is difficult to perform painting, etc., and even if it is possible, the rust prevention treatment is often insufficient. Therefore, over a long period of time, rust will develop on the inner end surface 23 of the metal end plate 17, and as this progresses, the airtightness of the bellows joint 21 will be impaired, resulting in a decrease in the durability of the vacuum interrupter. It was hot.

In view of the above-mentioned problems in the conventional vacuum interrupter, the present invention provides a vacuum interrupter that can surely prevent rust on the inner end surface of the end plate to which the bellows are joined, thereby improving reliability and durability. With the goal.

E Means for Solving Problems In the vacuum interrupter according to the present invention, the lead rod on the movable side is located on the inner circumferential side of the joint between the end of the metal bellows to which the lead rod is hermetically penetrated and the jointed metal end plate. The present invention is characterized in that a rust-preventive layer is formed by a brazing material layer on the vacuum chamber side end surface of the metal end plate.

F Effect: Since a rust preventive layer is formed using a brazing metal layer on the inner side of the metal end plate that cannot be subjected to rust preventive treatment, on the part facing the vacuum chamber and in contact with the atmosphere, rust can be reliably prevented from forming in this part.

G. Example The present invention will be explained based on the example shown in FIG. The outer peripheral end of a metal end plate 17 forming an annular bellows joint 21 is brazed to one end of the insulating cylinder 15 made of alumina ceramics via a metallized layer 24, and the bellows joint of this end plate 17 is brazed to one end of the insulating cylinder 15 made of alumina ceramics. The other end of a bellows 18 made of austenitic stainless steel, one end of which is joined to the movable lead rod 12, is brazed to the portion 21. The metal end plate 17 and the bellows 18 are coupled to each other by brazing the inner circumferential wall of the inner protrusion 25 of the metal end plate 17 and the outer circumference of the bellows cylindrical portion 26. A rust prevention layer 27 made of a brazing material layer is formed on the inner end surface 23 of the metal end plate 17, and the other parts of the metal end plate 17 exposed to the atmosphere on the outside are provided with rust prevention as in the past. A coating film 22 is formed.

The brazing material constituting the rust prevention layer 27 is Fe-
The metal end plate 17 is made of iron-based alloy such as Ni alloy or Fe-Ni-Co alloy, and has good fluidity. ), and there is no risk of stress corrosion cracking of the metal end plate 17, such as a nickel-based, copper-based, aluminum-based, gold-based, or palladium-based brazing material, it is desirable to use a brazing material. Note that silver-based brazing filler metals cannot be used because silver may enter grain boundaries within the iron-based alloy and cause grain boundary cracks.

The means for forming the anti-rust layer 27 by the brazing material layer is a plate brazing material having an annular shape corresponding to the inner end surface 23 of the metal end plate 17, or a ring-shaped wire brazing material having approximately the same shape as the inside of the bellows cylindrical portion 26. Inner end surface 2
3, and the brazing material for the anticorrosion layer 27 is made by increasing the amount of brazing material that connects the metal end plate 17 and the bellows 18, so that a part of the brazing material is placed on the metal end plate. 17 surface may be covered. Alternatively, a brazing material for the anti-rust layer 27 may be placed inside the bellows 18.

Note that the formation of the anti-corrosion layer 27 of the brazing material layer may be carried out specially only in this part, but when configuring the vacuum interrupter, the brazing material is interposed between each member and temporary assembly is performed, and at the same time this part is formed. It is preferable to place the filler metal in advance and heat and evacuate it all at once in a vacuum furnace for treatment.

Note that the present invention can also be applied to the configuration shown in FIG. 3, and it is sufficient to use a large amount of brazing filler metal.

H Effects of the invention According to the vacuum interrupter of the invention, a rust-preventive layer made of a brazing metal layer is formed on the end face facing the vacuum chamber on the inner circumferential side of the joint between the metal end plate and the bellows. The rust prevention treatment on the inside of the metal end plate, which could not be treated, can be reliably formed by the brazing material layer, thereby making it possible to obtain a vacuum interrupter with high durability and reliability.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view showing the structure of the main parts of an embodiment of the vacuum interrupter according to the present invention, Fig. 2 is a cross-sectional view showing the schematic structure of the vacuum interrupter, and Fig. 3 is the joint between the end plate and the bellows. It is a sectional view showing an example. Further, in the figures, 12 is a lead rod, 15 is an insulating tube, 17 is a metal end plate, 18 is a bellows, 22 is an anti-rust coating film, 23 is an inner end surface, and 27 is an anti-rust layer.

Claims (1)

[Scope of utility model registration request] One end of a substantially cylindrical metal bellows is provided in airtight contact with the vacuum chamber side of a metal end plate constituting a part of the vacuum container, and the bellows is positioned in the vacuum chamber, and the other end of the bellows is connected to the inner end. In a vacuum interrupter constructed by airtightly joining a lead rod having an electrode at the part thereof, the metal end plate is located at the brazed joint between one end side of the metal bellows and the metal end plate and on the inner circumferential side of the joint. A vacuum interrupter characterized by having a coating made of brazing material on the part that comes in contact with the atmosphere.