JPH041623Y2 - - Google Patents

Description

[Detailed description of the invention] A. Industrial application field The present invention relates to a vacuum interrupter, and in particular to a vacuum interrupter that has enhanced anti-corrosion ability for the metal bellows and the atmospheric contact portion of the inner wall of the metal member forming a part of the vacuum container. Regarding.

B. Summary of the invention The invention consists of joining a metal bellows and a bearing holding part to a metal member that forms part of a vacuum vessel, and providing a rust-preventive layer using a brazing filler metal on the part of the inner wall of the metal member that comes into contact with the atmosphere. This is a vacuum interrupter designed 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 with conventional painting or resin molding.

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 a metal end plate 16 joined to one end of an insulating cylinder 15, that is, one metal member forming a vacuum container, in a state of penetrating the metal end plate 16. The other lead rod (hereinafter referred to as a movable lead rod) 12 connected to a drive device (not shown) is a metal end plate that is the other metal member that is joined to the other end of the insulating cylinder 15 to form the vacuum container. 17 via a metal bellows 18, and the electrode 14 is connected to the fixed electrode 13 so that it can reciprocate in the opposite direction of the electrodes 13 and 14 as the drive device operates.
It is designed so that it can come into contact with. and,
A shield 20 that is held by the metal end plate 16 and surrounds the electrodes 13 and 14 is built into the vacuum chamber 19 in the insulating cylinder 15 that is kept in a vacuum. Electrodes 13, 14
This prevents metal vapor constituting the insulating cylinder 15 from adhering to the inner wall of the insulating cylinder 15 and causing insulation failure.

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.

FIG. 3 shows an example of the cross-sectional structure of the joint portion (in the direction of the arrow in FIG. 2) between the bellows and the end plate in such a vacuum interrupter. The other end of the metal bellows 18, whose one end is joined to the movable lead rod 12, is connected to the annular bellows joint 2 of the metal end plate 17.
1 is brazed. In order to smooth the reciprocating motion of the movable lead rod 12, a bearing 22 made of resin such as nylon or tetrafluoroethylene resin is held at the inner peripheral end of the metal end plate 17 via an adhesive layer 23. It is also known that a holding portion 24 is formed, and the reference numeral 25 in the figure is a rust-proofing protective layer formed by painting or resin molding.

D Problems to be solved by the invention In the vacuum interrupter shown in FIGS. 2 and 3, the metal end plate 17 is generally used.
Metals such as Fe-Ni alloys and Fe-Ni-Co alloys tend to rust when exposed to the atmosphere, so they need to be treated to prevent rust.

However, the bearing holding portion 24 , which is the end face radially inner than the bellows joint 21 on the side of the bellows joint 21 , is connected to the movable lead rod 12 and the metal end plate 17 .
Due to the small gap between the two parts, it is difficult to perform anti-rust treatment by painting, resin molding, etc., and even if it is possible, the anti-rust treatment is often insufficient. For this reason, over a long period of time, the atmosphere passing through the small gap between the movable lead rod 12 and the bearing 22 will cause rust to form on the inner wall of the bearing holding part 24 of the metal end plate 17, and this will progress and the airtightness of the bellows joint part 21 will deteriorate. As a result, it becomes difficult to maintain the degree of vacuum as a vacuum interrupter, and its durability is reduced.

Therefore, as shown in FIG. 4, the metal end plate 26 including the bearing holding part 24 is made of rust-resistant austenitic stainless steel or Inconel alloy. A vacuum interrupter configured to be used only as a sealing fitting 27 for airtight connection between an insulating tube 15 and an end plate 26, which can be subjected to anti-corrosion treatment from the outside, was developed in U.S. Patent No. 61-24929.
Known by the number. Items with the same reference numerals as those in Figure 3 above indicate products equivalent to these.
Descriptions of these will be omitted.

However, in this vacuum interrupter, a new airtight seal part by brazing is formed at the joint part A between the metal end plate 26 and the sealing fitting 27, which becomes a cause of a decrease in reliability.

In view of the above-mentioned problems in the conventional vacuum interrupter, the present invention provides a vacuum interrupter that can reliably prevent rust on the end plate without adding a new airtight seal part and improve reliability and durability. The purpose is to

E Means for solving the problem The present invention airtightly connects one end side of a metal bellows to the inner wall side of a metal member constituting a part of a vacuum container,
The other end of the metal bellows located in the vacuum container is hermetically connected to a movable lead rod having an electrode at the inner end, and the movable lead rod is positioned between the metal bellows and the movable lead rod. In a vacuum interrupter provided with a bearing holding part to which a guiding bearing is attached, the metal member and the bearing holding part are joined by brazing using different materials, and the joint part between the metal member and the metal bellows and the metal A rust-preventing layer made of a brazing material is provided on the inner wall of the metal member at the part of the metal member that is in contact with the atmosphere between the member and the joint portion of the bearing holding portion.

Note that the metal member is Fe-Ni alloy, Fe-Ni-
It is made of an alloy such as a Co alloy, and is not limited to a so-called plate-shaped end plate, but may also be a cup-shaped one. In addition, brazing filler metals include Ni-based, Cu-based, Al-based,
Furthermore, the bearing holding part is not limited to brazing to the inner wall side of the metal member.
It may be brazed to the outer wall side.

F Effect Since the inner wall side of the metal member between the joint between the metal bellows and the bearing holding fitting is covered with a rust-preventing layer made of brazing material, this brazing material film functions as a rust-preventing layer and prevents the movable lead rod and bearing from interfering with each other. This prevents the inner wall surface of the metal member from rusting due to the atmosphere passing through the sliding gap.

G. Example The present invention will be explained based on the example shown in FIG. Note that parts given the same reference numerals as those in FIGS. 2 to 4 described above indicate equivalent products, and detailed explanations thereof will be omitted.

At one end of the insulating tube 15 made of alumina ceramics, the outer circumferential end of a metal member (hereinafter simply referred to as an end plate) 28 having an annular bellows joint 21 formed thereon is connected via a metallized layer 29. The bellows joint 21 of the end plate 28 has one end joined to the movable lead rod 12 and the other end of a metal bellows (hereinafter simply referred to as bellows) 18 made of austenitic stainless steel is brazed. It is attached.

A cylindrical bearing holding fitting 30 made of the same material as the bellows 18 is brazed to the inner peripheral end of the end plate 28, and the movable lead rod 12 is slidably attached to the bearing holding fitting 30. A penetrating resin bearing 22 is integrally attached with an adhesive layer 23 interposed therebetween. The inner wall surface of the end plate 28 between the joint parts of the end plate 28 and the bellows 18 and the bearing holding fitting 30 is covered with a rust-preventing layer 3 made of a brazing material.
1 is formed, and the outer wall surface (outer surface) of this end plate 28
Rust-preventive protective layer 2 is applied by painting or resin molding.
5 is provided.

The brazing material constituting the anti-rust layer 31 is as follows:
The end plate 28 is made of a metal that easily rusts when exposed to the atmosphere, such as Fe-Ni alloy or Fe-Ni-Co alloy, which has good fluidity and high steam as it is necessary to braze in a vacuum furnace. It is desirable to use a brazing material that has a low pressure component (volatile component) and is free from the risk of causing stress corrosion cracking of the end plate 28, such as a nickel-based, copper, aluminum-based, gold-based, or palladium-based brazing material. Note that silver-based brazing filler metals cannot be used because there is a risk that silver will enter the grain boundaries within the iron-based alloy and cause grain boundary cracks.

The anti-rust layer 31 may be formed using a brazing filler metal for bonding the bellows 18 and the end plate 28 or a brazing filler metal for bonding the bearing holding fitting 30 and the end plate 28. Or rust prevention layer 3
In order to form 1, a plate solder or a wire solder may be specially arranged.

H. Effects of the invention According to the vacuum interrupter of the invention, the metal member forming a part of the vacuum container and the bearing holding fitting to which the bearing for guiding the movable lead rod is attached are formed as separate members, and the metal member and Since the inner wall surface of this metal member between the joints with the metal bellows and the bearing holding fittings is covered with a rust-preventive layer made of brazing material, the inner wall surface of the metal member, which was conventionally exposed to the atmosphere, is now directly exposed to the atmosphere. Therefore, the occurrence of rust can be effectively prevented, and thereby a vacuum interrupter with high durability and reliability can be obtained.
As a result, although Fe can be directly bonded to alumina ceramics as a metal component, it is prone to rust.
-Ni alloy and Fe-Ni-Co alloy can be used, and this allows the metal member to be formed of a single material and a single structure, which contributes to the elimination of airtight seals and improves reliability.

Furthermore, since the bearing holding fitting can be provided at a location unrelated to the airtight seal on the atmosphere side, the bearing holding fitting can be made of a material different from the metal member, such as austenitic stainless steel, which is unlikely to rust. .

[Brief explanation of drawings]

Fig. 1 is a 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 sectional view showing the schematic structure of the vacuum interrupter, and Figs. 3 and 4 are the end plate and bellows thereof. FIG. 3 is an enlarged cross-sectional view showing an example of a joint portion with the above. Also, in the figure, 12 is a movable lead rod, 15 is an insulating cylinder, 18 is a metal bellows, 22 is a bearing, 25
28 is a metal end plate, 30 is a bearing holding fitting, and 31 is a rust preventive layer.

Claims (1)

[Scope of utility model registration request] One end of a metal bellows is provided in airtight contact with the inner wall side of a metal member that constitutes a part of the vacuum container and through which the movable lead rod passes, and the metal bellows is positioned within the vacuum container, and the other end of the metal bellows is provided. a bearing holder, the side of which is in airtight contact with a movable lead rod having an electrode at the inner end thereof, and a bearing that is located between the metal bellows and the movable lead rod and that guides the movable lead rod is mounted; In the vacuum interrupter, the metal member and the bearing holding portion are formed of different materials and are joined by brazing, and the joint portion of the metal member and the metal bellows is connected to the metal member and the bearing holding portion. A vacuum interrupter characterized in that a rust-preventing layer made of a brazing material is provided on the inner wall of the metal member at a portion in contact with the atmosphere between the joint portion and the joint portion of the bearing holding portion.