JPH0422507Y2 - - Google Patents

Description

[Detailed description of the invention] A. Industrial field of application The invention applies to the atmosphere side of the inner wall of the metal end plate where the bellows and the insulating cylinder are joined to form a part of the vacuum vessel, and the atmosphere side of the bellows joint. This article relates to a vacuum interrupter with enhanced anti-corrosion properties.

B. Summary of the invention By brazing and joining one end of the bellows and one end of the cylindrical bearing holding fitting surrounding the movable lead rod to the inner wall side of the metal end plate that forms part of the vacuum vessel, It is intended to improve the durability and reliability of vacuum interrupters by strengthening rust prevention in areas where conventional methods such as painting or resin molding are difficult to prevent rust.

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 third 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 one metal end plate 16 whose outer periphery is joined to one end of an insulating tube 15 to form a vacuum container, while passing through the metal end plate 16 . The other lead rod (hereinafter referred to as a movable lead rod) 1 connected to a drive device (not shown)
2 is connected via a bellows 18 to the other metal end plate 17 whose outer peripheral edge is joined to the other end of the insulating cylinder 15 to form the vacuum container, and the electrodes 13 and 14 are The electrode 14 is capable of reciprocating in opposite directions and comes into contact with the fixed electrode 13. A metal end plate 1 is placed in a vacuum chamber 19 in an insulating cylinder 15 that is kept in a vacuum.
6 and surrounds the electrodes 13, 14.
0 is incorporated to prevent metal vapor constituting the electrodes 13 and 14 from adhering to the inner wall of the insulating cylinder 15 due to an arc generated when the electrodes 13 and 14 are brought close to each other, thereby preventing insulation failure from occurring.

By the way, racemics 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 bonded 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. 4 shows an example of the cross-sectional structure of the joint portion (in the direction of the arrow in FIG. 3) between the bellows and the end plate in such a vacuum interplater. In FIG. 4, the other end of the bellows 18 that is joined to the movable lead rod 12 passing through the metal end plate 17 is connected to the metal end plate 17 whose outer peripheral end is sealed or brazed to one end of an insulating cylinder (not shown). It is brazed to a bellows joint 21 having an annular shape. In order to smooth the reciprocating movement of the movable lead rod 12, a bearing 2 made of resin such as nylon or tetrafluoroethylene resin is installed at the inner peripheral end of the metal end plate 17.
2 via an adhesive layer 23
4 is also known, and the reference numeral 25 in the figure is a rust-preventing protective layer formed by painting or resin molding.

Further, as shown in FIG. 5, a stepped portion is formed on the inner peripheral side (on the movable lead rod 12 side) of the metal end plate 17, and this step is made to protrude outward (downward in the figure) to form a cylindrical connecting portion. 26 is also known. A bearing for the movable lead rod 12 is attached to this cylindrical connecting portion 26 as in the case of FIG. 4 described above,
Alternatively, an insulating frame constituting a vacuum interrupter or disconnector may be inserted to fix the vacuum interrupter.

D Problems to be solved by the invention Metals such as Fe-Ni alloy and Fe-Ni-Co alloy that form the metal end plate 17 used in the vacuum interrupter shown in Figs. 3 to 5 are Since it is easy to rust when exposed to the atmosphere, it is necessary to perform rust prevention treatment, and a rust prevention protective layer 25 is formed on the outer surface of the metal end plate 17 by painting, resin molding, or the like.

By the way, since the bellows 18 is brazed to the metal end plate 17 so as to partition the inner wall portion of the metal end plate 17 exposed to the atmosphere, the brazed portion may be damaged during repeated opening and closing. There was a risk of vacuum leakage.

Moreover, the bearing holding part 24, the connecting part 26, etc. located on the bellows joint part 21 side radially inward (atmospheric side) of the bellows joint part 21 may have a small clearance with the movable lead rod 12. Therefore, it is difficult to perform anti-rust treatment such as painting or resin molding on the inner wall surface A of the bearing holding portion 24 and the connecting portion 26, 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 gap between the movable lead rod 12 and the bearing 23 or the connecting part 26 will cause rust to form on the inner wall surface A of the bearing holding part 24 of the metal end plate 17 and the connecting part 26. As the vacuum interrupter progresses, the airtightness of the bellows joint 21 is impaired, resulting in a drawback that the durability as a vacuum interrupter is reduced.

In view of the above-mentioned problems in the conventional vacuum interrupter, the present invention has been developed to ensure durability and reliability by ensuring rust prevention on the atmosphere side of the inner wall surface of the metal member on the side where the bellows is provided, which forms a part of the vacuum container. It is an object of the present invention to provide a vacuum interrupter that can improve the performance of the vacuum interrupter.

E Means for Solving the Problems The vacuum interrupter according to the present invention has a metal end plate whose outer peripheral edge is hermetically brazed to an insulating cylinder forming a part of the vacuum container, and one end which is inside the metal end plate. A bellows whose circumferential side is hermetically brazed and whose other end is hermetically brazed to a movable lead rod; and a bearing which is made of a highly corrosion resistant material and has one end through which the movable lead rod can slide. A vacuum interrupter having a cylindrical bearing holding fitting that is integrally provided and whose other end is hermetically brazed to the inner peripheral side of the metal end plate and to one end of the bellows, the metal end plate and the The inner wall portion of the metal end plate located on the atmosphere side is held airtight by the other end of the bearing holding fitting with the airtight brazed portion with one end side of the bellows as a boundary, and the inner wall portion of the metal end plate located on the atmosphere side is held airtight by the other end of the bearing holding fitting. It is characterized by a rust-proofing protective layer formed on the outer wall portion.

Further, in the present invention, the metal end plate is formed of an Fe-Ni alloy or Fe-Ni-Co alloy that can be directly bonded to an insulator such as alumina ceramics, and may be either approximately plate-shaped or cup-shaped. The bearing retainer is made of highly corrosion-resistant austenitic stainless steel or Inconel alloy, and is placed between the bellows and the movable lead rod (see Figure 4), or along the movable lead rod. It is arranged so as to protrude outward (see Fig. 5). Furthermore,
The anti-rust protective layer provided on the outer surface of the metal end plate material is applied by painting or resin molding.

F Effect: The part of the inner wall surface of the metal end plate on the side where the bellows is installed, which forms part of the vacuum vessel, is not in direct contact with the atmosphere, and rust occurs on the inner wall surface of the metal end plate. is prevented.

G. Example The present invention will be explained based on the example shown in FIGS. 1 and 2. Note that in these figures, parts given the same reference numerals as those in FIGS. 3 to 5 described above indicate equivalent products, and detailed explanations thereof will be omitted.

First, in the vacuum interrupter shown in FIG. 1, a metal end plate (hereinafter simply referred to as an end plate) 13, which is joined to an insulating cylinder 11 made of alumina ceramics and forms a part of the vacuum vessel, is made of Fe-Ni alloy or Fe −Ni
-Co alloy, while the bearing holding fitting 27 is made of austenitic stainless steel or Inconel alloy.

To explain specifically, the end plate 17 has a bellows 1.
A bellows joint 21 protruding inward is provided to braze and join the ends of the bellows 18 and the movable lead rod 17 on the inner wall surface of the end plate 17 closer to the movable lead rod 12 than the bellows joint 21. 15, one end side of the bearing holding fitting 27 is brazed and joined. In this way, by brazing the bellows 18 and the bearing holding fitting 27 together on the inner wall surface of the end plate 17, the atmosphere side of the inner wall surface of the end plate 13 is prevented from coming into direct contact with the atmosphere. Moreover, the ends of the bellows 18 are brazed on both the vacuum side and the atmosphere side.

The outer peripheral end of the end plate 17 is brazed to the insulating cylinder 15 via a metallized layer 28 of molybdenum, molybdenum, manganese, etc., and the movable lead rod 12 is slidably attached to the bearing holding fitting 27. A penetrating resin bearing 22 is integrally attached with an adhesive layer 23 interposed therebetween. Bellows joint 2
On the inner wall surface A of the end plate 17 on the inner circumferential side than 1, a rust preventive layer 29 made of brazing material is formed, which is entirely joined to the bearing holding fitting 27.
A rust-preventive protective layer 25 is formed by painting, resin molding, etc. on the portion exposed to the atmosphere.

The brazing material constituting the anti-rust layer 29 is as follows:
It has good fluidity for the end plate 17 made of iron-based alloy such as Fe-Ni alloy or Fe-Ni-Co alloy, and high vapor pressure components (volatile It is desirable to use a brazing material that has a small amount of components) and that does not cause stress corrosion cracking of the end plate 17, such as a nickel-based, copper-based, aluminum-based, gold-based, or palladium-based brazing material. Note that silver-based brazing filler metals cannot be used because silver may enter the grain boundaries within the iron-based alloy and cause grain boundary cracks.

Next, another embodiment will be described based on FIG.
The one shown in FIG. 2 has a connecting fitting 30, which is a bearing holding fitting of the present invention, arranged concentrically with the movable lead rod 12 and protruding outward (downward in the figure) from the end plate 17. It is.

Specifically, the inner end of the connecting fitting 30 is bent into a hook shape and is brazed together with the bellows 18 to the bellows joint 21 of the end plate 17.
The inner circumferential surface of the end plate 17 and the outer circumferential portion of the connecting fitting 30 are brazed to prevent the inner wall surface A of the end plate 17 from coming into contact with the atmosphere. Note that the entire inner wall surface A of the end plate 17 may be covered with a rust-preventing layer made of a brazing material.

The protruding end of the connecting fitting 30 is connected to the movable lead rod 1.
This connecting fitting 30 is connected to a drive device (not shown) in Fig. 2, but it is possible to use one made of the same material as the bearing holding fitting in the previous embodiment. Components having the same functions as those in the embodiment are designated by the same reference numerals.

H. Effects of the invention According to the vacuum interrupter of the invention, the metal end plate, which forms part of the vacuum vessel, and the bearing holding fitting are formed from separate members, and the metal end plate, the bellows, and the bearing holding fitting are each joined together. Since the inner wall surface of the metal end plate between the parts is airtightly covered with a rust prevention layer made of brazing material or through the brazing material, the inner wall surface of the metal end plate, which was conventionally exposed to the atmosphere, is no longer directly exposed to the atmosphere. Therefore, the generation of rust can be effectively prevented, and thereby a vacuum interrupter with high durability and reliability can be obtained. As a result, Fe-Ni alloy and Fe-Ni-Co alloy, which can be directly bonded to alumina ceramics but are prone to rust, can be used as the metal end plate. This allows the metal end plate to be made of a single material and has a single structure. Since it can be formed by using the same method, it can contribute to reducing the number of airtight seal parts and improve reliability. Furthermore, since the bearing retainer can be provided at a location unrelated to the airtight seal on the atmosphere side, the bearing retainer can be made of a different material than the metal end plate, such as austenitic stainless steel, which does not easily rust. . In addition, since the bellows is brazed to the metal end plate and bearing holding fitting on both the vacuum side and the atmosphere side, the airtight brazing strength is improved and it is extremely durable without being damaged by frequent repeated opening and closing. can be improved.

[Brief explanation of the drawing]

1 and 2 are cross-sectional views showing the structure of the main parts in each embodiment of the vacuum interrupter according to the present invention, FIG. 3 is a cross-sectional view showing the schematic structure of the vacuum interrupter, and FIGS. 4 and 5 are FIG. 3 is a sectional view showing an example of a joint portion between the end plate and the bellows. Also, in the figure, 12 is a movable lead rod, 15 is an insulating cylinder, 17 is a metal end plate, 18 is a bellows, 22
25 is a bearing, 25 is an anti-rust protective layer, 27 is a bearing holding fitting, 29 is an anti-rust layer, and 30 is a connecting fitting.

Claims (1)

[Scope of utility model registration request] A metal end plate whose outer periphery is hermetically brazed to an insulating cylinder forming a part of the vacuum vessel, one end of which is hermetically brazed to the inner periphery of the metal end plate, and the other end of which is a movable lead rod. A bellows is hermetically brazed to the metal end plate, and the bellows is made of a highly corrosion-resistant material. and a cylindrical bearing holding fitting hermetically brazed to one end of the bellows, the vacuum interrupter having an airtight brazed portion between the metal end plate and the one end of the bellows as a boundary to the atmosphere side. A vacuum characterized in that an inner wall portion of the metal end plate located therein is airtightly held by the other end portion of the bearing holding fitting, and a rust-proofing protective layer is formed on an outer wall portion of the metal end plate located on the atmosphere side. Interrupter.