JPH0896640A - Bushing equipment - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a bushing having a porcelain insulator having improved mechanical strength and also improved electrical reliability against dielectric breakdown. [Structure] A sealing surface 6 is provided on a cylindrical surface of the porcelain bushing 21 for maintaining a hermetically sealed mounting portion to an apparatus.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bushing device,
In particular, the present invention relates to a bushing device in which a bushing body is side-supported.

[0002]

2. Description of the Related Art Device mounting of a conventional bushing device will be described with reference to FIG. A support fitting 3 as a support member is bonded to the porcelain bushing 1 via a cement portion 2 as a joining material. On the other hand, the gasket 4 is installed on the sealing surface 6 which is a part of the device mounting surface 5. When this support fitting 3 is attached to the device mounting surface 5 and tightened with the mounting bolts 8, the gasket 4 is tightened and the device is sealed. Since the sealing surface 6 is installed vertically on the equipment mounting surface 5, that is, on the cylindrical surface of the porcelain bushing 1, the shape of the porcelain bushing 1 has a different diameter at this portion, that is, the mounting portion with the equipment, and becomes thinner with a step. Become.

[0003]

However, the insulator 1
Since the inner diameter of the porcelain was constant, the shape of the porcelain bushing 1 on the side of the device mounting portion was thin, and firing was difficult. Further, under such a shape, the porcelain insulator 1 was fragile, and moreover, stress was likely to be concentrated at the step portion, so that the mechanical strength was weak. Furthermore, gasket 4
Bushing seat 1 that holds the ground and is also grounded in terms of potential
Since the inner diameter of 1 also becomes smaller, the distance from the central conductor 7 becomes shorter, and the electric field at this portion becomes larger, which is not preferable for insulation. In particular, the insulating medium 12 of the device has a dielectric constant of 1
If it is significantly smaller than the dielectric constant of, the electric field in the gap between the bushing seat 11 and the porcelain bushing 1 becomes extremely large, and there is a possibility of dielectric breakdown. In addition, even if a medium such as insulating oil, which has no difference from the dielectric constant of the porcelain tube 1 is used as the insulating medium 12 of the device, if air bubbles accumulate in the gap between the bushing seat 11 and the porcelain tube 1, insulation There was a possibility of destruction.

Further, conventionally, the sealing surface 6 is arranged perpendicularly to the surface of the porcelain tube, and the gasket 4 is compressed by tightening the mounting bolt 8. Therefore, in the cement portion 2, the gasket 4 is compressed. Shear force is generated. The shearing force due to the bolt fastening is generally much larger than the compressive force of the weight of the bushing exerted on the sealing surface 6 by the porcelain bushing 1, and a large-area bonding surface is required.

Therefore, the present invention has been made to solve the above-mentioned problems of the prior art, and its object is to provide a bushing device having a porcelain tube with improved mechanical strength and electrical reliability against dielectric breakdown. To provide.

[0006]

In order to achieve the above-mentioned object, the present invention inserts a current-carrying conductor inside a porcelain bushing and inserts one end of this porcelain bushing into an opening provided in a predetermined device in a secret manner. In the bushing device in which the porcelain bushing is laterally supported by the support member attached to the opening end, the side surface of the porcelain bushing is hermetically joined to the gas seal provided in the opening and also joined to the support member. Supports joining through materials.

Further, in order to achieve the above object, the present invention provides a bushing device according to claim 1, wherein the surface of the sealing surface is coated with conductive grease.

[0008]

With such a structure, since the cross section of the cylinder near the device mounting portion of the porcelain insulator has a spatial allowance, the thickness of the porcelain insulator can be made uniform and the mechanical strength can be enhanced. At the same time, the insulation distance can be made longer, so that the electrical reliability can be improved. Further, since the compressive force due to the bolt fastening of the gasket to the porcelain bushing does not act as the shearing force to the cement portion, it is possible to reduce the bonding area of the cement portion.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. The same parts as those in FIG. 4 are designated by the same reference numerals and the description thereof will be omitted. The sealing surface 6 is installed along the surface of the cylindrical surface of the insulator. Further, the porcelain insulator 21 has a structure having almost no different diameter portion except for the shade.

That is, since the sealing surface 6 is provided on the cylindrical surface in the vicinity of the device mounting portion of the porcelain insulator 21, there is a spatial allowance in the cross-section of the cylindrical device mounting portion in the vicinity thereof, and the thickness is almost constant except for the shade. It is possible to obtain a porcelain insulator having excellent mechanical strength. As a further effect, since the insulation distance between the central conductor 7 having a high potential and the bushing receiving seat 11 having a ground potential can be made large, the electric field can be relaxed.

Next, another embodiment of the present invention will be described with reference to FIG.
Will be described with reference to. The same parts as those in FIG. 4 are designated by the same reference numerals and the description thereof will be omitted. The sealing surface 6 is installed along the surface of the cylindrical surface of the insulator. Further, a support metal fitting 13 having a low height is bonded to the porcelain bushing 31 via the cement portion 2.

By the way, as described above, in the prior art shown in FIG. 4, the sealing surface 6 is arranged perpendicularly to the surface of the porcelain tube surface, and the gasket 4 is compressed by tightening the mounting bolts 8. In the portion 2, a shearing force is generated by bolt fastening.

However, in the present invention, since the seal surface 6 is installed along the surface of the porcelain tube cylindrical surface, the cement portion 2
The shearing force due to the weight of the bushing having the porcelain bushing and the current-carrying part acts on the bearing. However, since this shearing force is smaller than the shearing force due to the bolt fastening as described above, it is as wide as the bonding surface in the prior art. There is no need to take it. That is, since the bonding area of the support fitting 13 can be reduced by that much, the total length of the bushing device can be shortened. Therefore, the entire porcelain insulator can be made into a simple and compact structure, and the porcelain insulator can be easily molded and fired.

Next, regarding still another embodiment of the present invention,
This will be described with reference to FIG. The same parts as those in FIG. 4 are designated by the same reference numerals and the description thereof will be omitted. A compound 9 may be applied to the sealing surface 6 when the bushing is inserted into a device, but in this embodiment, conductive grease is used as the compound 9.

In the conventional technique shown in FIG. 4, in order to avoid concentration of the electric field on the bushing receiving end portion 10, it is necessary to round the edge of the end portion to eliminate the electric field sharp edge portion. However, in this embodiment, the conductive grease is applied to the bushing seat 11
If the coating is made thicker than the thickness of, the electric potential distribution in the vicinity of the bushing seat 11, which is the ground electric potential portion, becomes uniform, and the concentration of the electric field can be avoided. Further, this conductive grease serves to prevent rust on the equipment mounting surface 5.

Further, according to the present invention, there is a possibility that the surface of the porcelain bushing may rub against the gasket when the bushing is inserted into the device. In design, the surface of the porcelain porcelain is polished in order to obtain the surface accuracy of the porcelain porcelain, and only the gasket contacting part is actually rubbed. Therefore, there are not many sliding problems. Moreover, if an O-ring is used for the gasket 4 and grease is applied to the sliding surface, the sliding problem is almost solved.

[0017]

As described above, according to the present invention, since there is a spatial allowance in the cross section of the cylinder in the vicinity of the device mounting portion of the porcelain bushing, the thickness of the porcelain bushing can be made uniform and the mechanical strength can be improved. At the same time, the electric field reliability can be improved. Further, the molding and firing of the porcelain tube become easy.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a mounted state of a bushing device according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a mounted state of a bushing device according to another embodiment of the present invention.

FIG. 3 is a cross-sectional view showing a mounted state of a bushing device according to still another embodiment of the present invention.

FIG. 4 is a cross-sectional view showing a mounted state of a conventional bushing device.

[Explanation of symbols]

21 ... Insulator pipe, 2 ... Cement part, 3 ... Support metal fittings, 6 ... Sealing surface, 7 ... Central conductor, 9 ... Compound.

Claims (2)

[Claims] 1. A conductive conductor is inserted into the porcelain tube, one end of the porcelain tube is hermetically inserted into an opening provided in a predetermined device, and a support member attached to the outer peripheral surface of the open end is used. In a bushing device that supports the porcelain tube from the side, a side surface of the porcelain tube is airtightly joined to a sealing surface provided on the inner side surface of the opening via a gasket, and the support member is joined and supported via a joining material. Bushing device characterized by being processed. 2. The bushing device according to claim 1, wherein conductive grease is applied to the surface of the sealing surface.