JP2000306445A - Bushing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bushing having reliability enhanced by inhibiting the occurrence of electrolytic corrosion due to water invasion, by enhancing the joint strength of an aluminum material or a main material of an upper flange to a plated copper material to prevent the exfoliation of the two. SOLUTION: In this bushing, an upper flange 23 on an upper part of a center conductor 3 is made by joining a copper material 11 to an aluminum material 12. A lower part of the copper material 11 is embedded in an upper part of the aluminum material 12 while an upper part thereof is exposed from the aluminum material 12. The lower part of the copper material 11 embedded in the aluminum material 12 has the shape of a downwardly widening truncated cone and the upper part of the exposed copper material 11 has the shape of a cylinder with an outer diameter smaller than the outer diameter of the truncated cone.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bushing having an upper flange connected to an overhead line, and more particularly to a bushing having an improved joining technique of a copper material and an aluminum material constituting the upper flange. is there.

[0002]

2. Description of the Related Art Conventionally, gas insulated switchgears, gas circuit breakers, and the like have been widely used as power transmission and transformation equipment. When these devices are of the air insulation type, a bushing is generally arranged at the outlet. An upper flange is provided at an upper portion of the bushing, and an overhead wire is connected to the upper flange. A conventional example of such a bushing will be specifically described with reference to FIGS.

[0005] As shown in FIG. 5, a bushing is provided with a porcelain tube 1 for the purpose of air insulation and supporting members.
A cylindrical central conductor 3 for passing a current to the main body of the apparatus is provided in the insulator tube 1, and an inner shield 4 for controlling an internal electric field is arranged below the insulator tube 1.

An upper flange 2 is fixed to an upper part of the center conductor 3. On the upper surface of the upper flange 2, a square or rectangular connection portion 2 a is raised, and a terminal plate 6 is attached with a clad plate 5 interposed therebetween. An overhead wire is connected to the upper flange 2 via the terminal plate 6.

As shown in FIG. 6, the clad plate 5 comprises a silver plated portion 7 and an aluminum material 8 joined by explosion or the like. The connecting portion 2a is disposed on the aluminum material 8 side, and the terminal plate 6 is disposed on the silver plating portion 7 side. The clad plate 5 and the terminal plate 6 are mounted on the connecting portion 2a by mounting bolts 9. The silver plating 7 is formed by applying silver plating to a copper material.

The material of the upper flange 2 is mainly aluminum because it is lighter than copper and has good workability. However, the portion of the upper flange 2 where the terminal plate 6 is connected needs to be plated with silver or tin in order to enhance the current-carrying performance. However, plating on aluminum has not been applied due to the problem of adhesion.

Therefore, conventionally, as described above, the clad plate 5 having the silver plated portion 7 is sandwiched between the mounting portion 2a of the upper flange 2 and the terminal plate 6, so that the silver plated portion 7 and the terminal plate 6 , The terminal plate 6 is attached to the upper flange 2. As a method of attaching the terminal plate 6 other than using the clad plate 5, the upper flange 2
A copper material is soldered to the connecting portion 2a of the above, and silver plating is applied to the copper material.

[0008]

However, the above prior art has the following problems. That is, in the clad plate 5, since the outer peripheral portions of the silver plated portion 7 and the aluminum plate 8 were the same, the bonding strength between the two was low. Therefore, when a strong impact is received from the outside, there is a possibility of peeling. When the silver-plated portion 7 and the aluminum plate 8 are separated, water may enter from the separated portion, causing electrolytic corrosion and leading to poor conduction of the bushing.

The present invention has been proposed to solve such problems, and an object of the present invention is to increase the bonding strength between an aluminum material, which is a main material of an upper flange, and a copper material to be plated. Another object of the present invention is to provide a bushing in which the separation of the two is prevented, thereby suppressing the occurrence of electrolytic corrosion due to the intrusion of water and improving the reliability.

[0010]

In order to achieve the above object, the present invention relates to a bushing in which an upper flange connected to an overhead wire is fixed above a central conductor and has the following structural features. are doing.

According to a first aspect of the present invention, an upper flange is formed by joining a molten aluminum material around a lower portion of the copper material while exposing the upper portion of the copper material, and joining the copper material and the aluminum material. And the outer diameter of the lower portion of the copper material buried in the aluminum material is larger than the outer diameter of the upper portion of the copper material exposed.

In the first aspect of the present invention having the above configuration,
By using molten forging, the shape of the copper material becomes relatively wide, and it is possible to easily join a copper material having a different outer diameter dimension to an aluminum material at the top and bottom. Therefore, by making the outer diameter of the lower part of the copper material incorporated in the aluminum material larger than the outer diameter of the upper part of the copper material, the copper material can be firmly joined to the aluminum material. Therefore, even if a strong impact is applied to the upper flange from the outside, there is no possibility that the copper material and the aluminum material are separated, and the corrosion of the bushing can be reliably improved by preventing the electrolytic corrosion due to the intrusion of water.

According to a second aspect of the present invention, in the bushing of the first aspect, the lower portion of the copper material is formed in a truncated cone shape. According to a third aspect of the present invention, in the bushing according to the first aspect, a lower portion of the copper material has a disk shape.

According to the second and third aspects of the present invention, the lower part of the copper material is made larger than the upper part of the copper material by an extremely simple shape. The joining strength can be increased.

The invention according to claim 4 is the invention according to claim 1, 2, or 3.
In the bushing described above, a connection portion for the overhead wire is set up on the upper portion of the copper material. According to the fourth aspect of the present invention, it is possible to attach a terminal plate having a simple shape to the raised connection portion.
It is possible to further simplify the configuration.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION

(1) First Embodiment [Configuration] Hereinafter, a first embodiment of the present invention will be specifically described with reference to FIG. The first embodiment corresponds to claims 1 and 2, and FIG. 1 is a sectional view of a main part of the first embodiment. The same members as those in the conventional example shown in FIGS. 5 and 6 are denoted by the same reference numerals, and description thereof will be omitted.

As shown in FIG. 1, an upper flange 23 is fixed above the center conductor 3. The upper flange 23 is made of a joint product of the copper material 11 and the aluminum material 12. The lower part of the copper material 11 is embedded in the upper surface of the aluminum material 12, and the upper part is exposed from the aluminum material 12. The lower part of the copper material 11 buried in the aluminum material 12 has a truncated conical shape spreading downward. The exposed upper portion of the copper material 11 has a cylindrical shape having an outer diameter smaller than the outer diameter of the truncated cone. Furthermore, silver plating is applied to the upper part of the copper material 11, and an L-shaped terminal plate 13 is fixed by mounting bolts 14.

For joining the copper material 11 and the aluminum material 12 described above, a so-called molten metal forging method is used. That is,
The copper material 11 having the above-described shape is fixed inside the mold, and the molten aluminum material 12 is poured into the mold. At this time, only the periphery of the lower part of the copper material 11 is filled with the aluminum material 12, and the upper part of the copper material 11 is exposed. In this state, pressure is applied to join the copper material 11 and the aluminum material 12 together.

[Operation and Effect] In the first embodiment having the above configuration, the copper material 11 can be formed by using a molten metal forging method.
Is relatively free, and the copper material 11 having a different outer diameter dimension in the upper and lower portions can be easily joined to the aluminum material 12. Therefore, the lower part of the copper material 11 incorporated in the aluminum material 12 can be formed into a truncated cone shape larger than the upper part of the copper material 11, so that the copper material 11 can be firmly joined to the aluminum material 12. Moreover, since the lower part of the copper material 11 is made larger than the upper part of the copper material 11 by a simple shape such as a truncated cone, the configuration can be simplified easily.

As described above, according to the first embodiment, plating is performed by an extremely simple structure, such as forming the upper flange 23 from a joined product of the copper material 11 and the aluminum material 12 by a molten metal forging method. The joining strength between the copper material 11 and the aluminum material 12 that is the main material of the upper flange 23 can be increased. Therefore, even if the upper flange 23 receives a strong impact from the outside, the copper material 11 and the aluminum material 12 do not peel off. As a result, the occurrence of electrolytic corrosion due to the intrusion of water can be reliably prevented. Thus, the bushing can always maintain a good energized state, and the reliability can be improved.

(2) Second Embodiment [Structure] A second embodiment corresponds to claims 1 and 3, and FIG. 2 is a sectional view of a main part of the second embodiment. . As shown in FIG. 2, the upper flange 24 according to the second embodiment is a joined product of a copper material 21 and an aluminum material 22 by a molten metal forging method. The feature of the second embodiment is that the lower part of the copper material 21 buried in the aluminum material 22 has a disk shape having an outer diameter larger than the outer diameter of the exposed upper part of the copper material 21.

[Operation and Effect] The second embodiment having such a configuration
According to the embodiment, by forming the lower part of the copper material 21 incorporated in the aluminum material 22 into a disk shape larger than the upper part of the copper material 21, the copper material 21 can be firmly joined to the aluminum material 22. it can. Therefore, even if the upper flange 24 receives a strong external impact, there is no possibility that the copper material 21 and the aluminum material 22 are separated. Therefore, similarly to the first embodiment, it is possible to prevent electric corrosion due to intrusion of water and contribute to improvement of reliability.

(3) Other Embodiments The present invention is not limited to the above-described embodiments. For example, the embodiment shown in FIGS. It is a modification of the second embodiment. These embodiments are characterized in that connection portions 11a and 21a for overhead wires are set up on the upper surfaces of copper materials 11 and 21. The connection portions 11a and 21a are formed in a square or a rectangle, and are plated with silver.

The above embodiment corresponds to claim 4, in which the terminal plate 6 having a simple shape can be attached to the connecting portions 11a and 21a instead of the L-shaped terminal plate 13 as in the prior art. Therefore, in addition to the above-described effects, there is an advantage that the configuration can be simplified.

The shapes and dimensions of the copper material and the aluminum material constituting the upper flange can be changed as appropriate, and the shape of the copper material is such that only the lower portion has a truncated cone shape as in the first embodiment. Instead, an embodiment in which the entire copper material is formed in a truncated cone shape is also included.

[0026]

As described above, according to the bushing of the present invention, the main material of the upper flange is formed by a very simple structure such as forming the upper flange from a joint product of a copper material and an aluminum material by molten metal forging. The joint strength between a certain aluminum material and the copper material to be plated was increased to prevent the two from being separated, and the occurrence of electrolytic corrosion due to the intrusion of water was suppressed, thereby improving reliability.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of a first embodiment according to the present invention.

FIG. 2 is a sectional view of a main part of a second embodiment according to the present invention.

FIG. 3A is a sectional view of a main part of another embodiment according to the present invention, and FIG. 3B is a side view of the same.

FIG. 4 (a) is a sectional view of a main part of another embodiment according to the present invention, and FIG. 4 (b) is a side view of the same.

FIG. 5 is a sectional view of a conventional bushing.

FIG. 6 is a sectional view of a main part of a conventional bushing.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Insulator tube 2, 23, 24 ... Upper flange 2a, 11a, 21a ... Connection part 3 ... Center conductor 4 ... Inner shield 5 ... Cladding plate 6, 13 ... Terminal plate 7 ... Silver plating part 8, 12, 22 ... Aluminum material 9,14 ... Mounting bolts 11,21 ... Copper

Claims (4)

[Claims] 1. A bushing in which an insulator tube is provided, a center conductor is provided in the insulator tube, and an upper flange connected to an overhead wire is fixed to the upper portion of the center conductor. The molten aluminum material is poured around the lower part of the material, and the copper material and the aluminum material are joined by applying pressure to the aluminum by forging,
A bushing comprising the upper flange, wherein an outer diameter of the lower part of the copper material buried in the aluminum material is larger than an outer diameter of the upper part of the copper material exposed. 2. The bushing according to claim 1, wherein a lower portion of said copper material has a truncated cone shape. 3. The bushing according to claim 1, wherein a lower portion of said copper material has a disk shape. 4. A bushing according to claim 1, wherein a connection part to said overhead wire is raised above said copper material.