JPH0141136Y2 - - Google Patents

Description

[Detailed description of the invention] [Technical field to which the invention pertains] This invention is an insulating paper used for the purpose of mitigating the electric field at the oil-immersed ends of bushings used in oil-immersed electrical equipment or at oil-immersed high-voltage conductor connections. This invention relates to shields insulated using It is desired that this type of shield insulation be easily and inexpensively insulated.

[Prior art and its problems]

Fig. 1 is a conventional structural diagram of a shield 2 provided around a metal fitting 1 at the end of the bushing.
The outer periphery and end portions of are insulated by pulp mold insulation 3. This product has the advantage of good appearance and good insulation properties, but has the disadvantage that it requires special technology and equipment, takes time to manufacture, and is expensive.

Figure 2 is also a conventional structural diagram of a shield provided surrounding the hardware 1 at the end of the bushing. crepe paper 22 made of crepe paper wrinkled into crepe shapes to make it flexible
It is insulated by covering it with. This has the disadvantage that when the voltage increases and the insulation thickness increases, when the crepe paper 22 is folded back at the end of the shield 21, the inner diameter side becomes thicker and molding becomes difficult.

[Purpose of invention]

The purpose of this invention is to overcome the drawbacks of the conventional structure described above and provide a shield insulated with insulating paper that is easy to manufacture and inexpensive.

[Key points of the idea]

In order to achieve the above object, according to the configuration of this invention, the insulation of the shield is made of a strip having a length and a width that can cover the most protruding curved part, where the electric field becomes more severe at both end faces, through the axial outer circumference of the shield. 1st
At least two types of crepe paper of different widths, consisting of an insulating paper and a second insulating paper wider than the first insulating paper, are overlapped and wrapped multiple times around the outer periphery of the shield, and are wrapped inwardly according to the shape of the shield. A shield is constituted by an insulating part formed by folding the insulating part, and a third insulating paper made of crepe paper, which is wider than the second insulating paper, which is wrapped around the insulating part and folded to cover and press the insulating part. .

[Example of idea]

Figures 3 to 5 are structural diagrams of an embodiment of this invention, in which a shield 2 is formed by folding both ends of a cylinder smoothly inward to cover a live part such as a metal fitting provided on the lower end surface of the bushing. The outer periphery of the shield, its ends, and a part of the inner periphery following the ends are covered and insulated with an insulator 31. The width of the insulator 31 is the length from the outer periphery of the shield 2 to the end of the curved part in contact with the shield 2, which is indicated by the dotted line in FIG. A first insulating paper 41 in the form of a band, and a second insulating paper 42 in the form of a band, which is wider than the insulating paper 41 and whose tip in the width direction reaches the tip bent inside the shield 2. An insulating section 43 formed by stacking at least two types of insulating papers with different widths and winding them around the outer periphery of the shield 2, and a third insulating paper wider than the second insulating paper 42 that covers and presses the insulating section. It consists of 44.

The insulating papers 41, 42, and 44 are made of crepe paper, which is a thin insulating paper with many crepe-like creases to give it flexibility and elasticity, thereby increasing its apparent thickness. And first and second insulating paper 41, 42
The wrinkles have been smoothed out in advance to reduce the apparent thickness.

As described above, the insulating papers 41 and 42 wound one on top of the other on the outer periphery of the shield 2 are brought into close contact with the inner periphery of the shield 2 in accordance with the shape of the shield 2 without tearing their widthwise ends. The insulating portion 43 can be easily prevented from unraveling by fixing its tip to an insulating band 45 such as a strip-shaped press board with glue.

[Effect of idea]

As is clear from the above explanation, according to the configuration of this invention, the part of the tip of the shield where the electric field is most severe is covered with at least two types of insulating papers 41 and 42 to obtain the necessary dielectric strength, and the inside Since the folded part has fewer layers of insulating paper, it is not particularly thicker than the outer periphery and difficult to work with, as in the past. In addition, both the insulating papers 41 and 42 can be made thinner by smoothing out the wrinkles of the crepe paper to a certain extent, so that an insulating layer made of insulating paper with a uniform thickness can be obtained without increasing the insulating thickness unnecessarily. It will be easier to leave it behind and do the work.

Since the third insulating paper 44 covers and presses the insulating portion 43, there is no need to particularly smooth out wrinkles using only the tension when wrapping it around the shield 2, so that sufficient elasticity remains and work can be done easily.

[Brief explanation of drawings]

Figures 1 and 2 are cross-sectional views of the conventional shield part, Figures 3 to 5 are cross-sectional views of the embodiment of this invention, Figure 3 is a cross-sectional view of the shield, and Figure 4 is a cross-sectional view of the shield before molding the insulating part. The sectional view, FIG. 5, is an enlarged view of the shield end. 2: Shield, 31: Insulator, 41: First insulating paper, 42: Second insulating paper, 43: Insulating section, 44: Third insulating paper, 45: Band.

Claims (1)

[Scope of Claim for Utility Model Registration] 1. A shield in which the outer periphery and both axial ends of a cylindrical shield that shields a live part, as well as a part of the inner periphery following the ends, are covered with insulating paper and insulated. , the insulating paper includes a first insulating paper in the form of a strip having a width that is long enough to cover the outer periphery of the shield and the ends of the curved portions at both ends in the axial direction, and an inner part of the insulating paper that is wider than the first insulating paper At least two types of crepe paper with different widths, including a second insulating paper that can cover the periphery further, are overlapped and wrapped around the outer periphery of the shield multiple times, and folded to match the shape of the shield to cover both axial ends of the inner surface of the shield. The third insulating paper is made of crepe paper and is wider than the second insulating paper, which is wrapped around the insulating part and folded to cover and press the insulating part. Shield with insulation. 2. An insulated shield according to claim 1 of the utility model registration, characterized in that the end of the third insulating paper is held down from the inner diameter side by a band made of an insulating material.