JPS6392212A - Insulating spacer - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) The present invention relates to an insulating spacer for connecting and supporting, for example, a bus conductor of a gas insulated switchgear such as a gas insulated bus bar, which houses a live part together with an insulating gas. Regarding.

(Prior Art) Gas-insulated electrical equipment is constructed by housing electrical equipment such as circuit breakers and disconnectors in a metal container filled with insulating gas.
Insulating spacers are provided at the connections between the containers to separate the gases between the containers. In this case, the insulating spacer is arranged so that its flange part is sandwiched between the flange parts of adjacent metal containers, and is tightened with a bolt passing through the flange part of the metal container and the insulating spacer. and (B) show an example of a generally used insulating spacer. This insulating spacer 1 has a bulge 3 that supports a conductor connection part 2 at a position near the center, and a peripheral flange. Embedded fittings 5, 5 for screwing or penetrating bolts into portion 4; ···have. Such an insulating spacer 1 is generally manufactured by integrally molding the embedded fitting 5 and the insulating main body 1b with epoxy resin, and heating and curing the resin at a predetermined temperature. However, in the cooling stage after casting the insulating spacer 1, there is a possibility that interfacial peeling phenomenon may occur at the contact surface between the embedded fitting 5 and the insulating main body 1b.

This interfacial peeling is caused in particular by the difference in coefficient of linear expansion between the embedded fitting 5 and the insulating main body 1b (approximately 1.5 to 2 times).

In addition, the presence of interfacial peeling is caused by the progress of interfacial peeling due to mechanical external forces such as bending, and furthermore, the presence of interfacial peeling is caused by the progress of interfacial peeling due to mechanical external forces such as bending, and furthermore, the presence of interfacial peeling is caused by the progress of interfacial peeling due to mechanical external forces such as bending. 5
As shown in FIGS. (A) and (B), cracks 6 may occur around the embedded metal fitting 5, which may reduce the strength of the insulating spacer 1. Therefore, attempts have been made to improve the adhesion at the contact surface between the embedded fitting 5 and the insulating main body 1b through chemical treatment to suppress the interfacial peeling and the progress of interfacial peeling, but there are still problems in terms of reliability. .

(Problems to be Solved by the Invention) As described above, in the conventional insulating spacer 1, interfacial peeling may occur between the embedded metal fitting 5 of the flange portion 4 and the insulating main body lb, resulting in a decrease in strength.

The present invention aims to eliminate the above-mentioned drawbacks, reduce the peeling stress generated between the embedded metal fitting and the insulating main body due to thermal stress, etc., and provide an insulating spacer for gas-insulated electric equipment that has high long-term reliability. purpose.

[Structure of the invention]

(Means for Solving the Problems) In order to achieve the above object, in the present invention, at least one end surface of the embedded metal fitting is provided with a counterbore.

(Function) With this configuration, the vicinity of the end face of the embedded fitting is easily deformed, and separation from the insulating body does not occur.

(Example) An embodiment of the present invention will be described with reference to FIG.

The insulating spacer 1 is approximately the same as that shown in FIGS. 4(A) and 4(B), and has a plurality of embedded metal fittings 5 on approximately the same circumference around the insulating main body 1b. Insulating spacer 1
Each of the embedded metal fittings 5 embedded in the flange portion 4 of is subjected to counterbore processing. That is, the embedded metal fitting 5 is formed into a substantially cylindrical shape with a thickness H, and a hole for inserting a bolt is provided in the center thereof. Also, counterbores 7 with a depth t are provided on both end surfaces of the embedded metal fitting 5. Further, it is desirable that the depth t of the counterbore 7 is 10 to 30% of the thickness H of the embedded metal fitting 5 in terms of mechanical strength, and the wall thickness of the embedded metal fitting 5 at the counterbore 7 portion is
It is desirable to set it to about 10% of the diameter.

Although the counterbore 7 is provided on both end surfaces of the embedded fitting 5 in this embodiment, it may be provided on only one end surface.

Let us now consider the influence of thermal stress generated in the insulating spacer 1 due to the temperature drop during resin curing during the manufacturing process. At this time, a large tensile force, that is, peeling stress, is generated at the end of the contact surface 8 due to the difference in linear expansion coefficient between the embedded fitting 5 and the insulating main body 1b.

If the counterbore 7 is not provided in the embedded fitting 5, the stress on the contact surface 8 changes linearly and becomes maximum at the upper and lower ends of the contact surface 8. However, by providing the counterbore 7 in the embedded metal fitting 5, the upper and lower ends of the contact surface 8, where the maximum stress was generated, can be easily deformed, and the stress at these locations is reduced. This will be explained using the stress distribution analysis diagram shown in FIG.

FIG. 2 shows the distribution of peeling stress on the contact surface 8, where the horizontal axis shows the peeling stress S, the vertical axis shows - in the direction of the thickness H of the embedded fitting 5 on the contact surface 8, and the origin is The center point in the thickness direction of the embedded metal fitting 5 is set where no tension occurs. Further, the broken line is the distribution of peeling stress when the counterbore 7 is not provided, and the solid line is the distribution of the peeling stress when the counterbore 7 is provided.

The peeling stress in the case where the counterbore 7 is not provided varies linearly with the change in the thickness direction of the embedded fitting 5, and reaches the maximum peeling stress S1 at the upper and lower ends of the contact surface 8. on the other hand.

When the counterbore 7 is provided, the peeling stress changes in a curved manner in the thickness direction, and reaches S at the upper and lower ends of the contact surface 8.

However, in this case, the region where the maximum peeling stress S2 occurs is not at the upper and lower ends of the contact surface 8, but at a location approximately equal to the depth t of the counterbore 7. Further, the maximum peel stress S in this case is smaller than the maximum peel stress S1 in the case where the counterbore 7 is not provided.

That is, by providing the counterbore 7 in the contact surface 8 of the embedded metal fitting 5, the upper and lower ends of the contact surface 8, where the maximum peeling stress has occurred, can be easily deformed, and the stress in these parts is reduced. As a result, the restriction on displacement at the depth position of the counterbore 7 is greatest, and the peeling stress here is the greatest.

Further, assuming that the adhesive force at the contact surface 8 between the embedded fitting 5 and the insulating main body 1b is uniform, the limit stress at the upper and lower ends of the contact surface 8 is half of the stress at other parts of the contact surface 8. As can be seen from FIG. 2, the peel stress 5 at the upper and lower ends of the contact surface 8 is approximately half of the maximum peel stress S2 generated at the depth position of the counterbore 7.

Therefore, the peel stress of the contact surface 8 is balanced in terms of strength. Further, as shown in FIG. 3, the embedded fitting 5 may have a counterbore in the fitting having screw holes passing through the upper and lower end surfaces.

Furthermore, although we have explained the single-phase insulating spacer here,
The same applies to three-phase bulk insulation spacers.

〔Effect of the invention〕

As explained above, according to the present invention, by providing a counterbore on at least one of the connection surfaces of the embedded fitting, peeling stress generated between the embedded fitting and the insulating body due to thermal stress, etc. can be reduced. The maximum value can be lowered, and an insulating spacer with excellent durability can be provided.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an insulating spacer showing one embodiment of the present invention, FIG. 2 is a peeling stress distribution diagram on a contact surface, and FIG. 3 is a partial sectional view of an insulating spacer showing another embodiment of the present invention. FIGS. 4(A) and 4(B) show a conventional insulating spacer, and FIGS. 4(A) and 4(B) are a plan view and a sectional view, respectively.
Figures 5(A) and 5(B) are enlarged views of Figure 4(A), and Figures 5(A) and 5(B) are of portions a and b of Figure 4(A), respectively. It is an enlarged view. 1... Insulating spacer 1b... Insulating main body 2...
Conductor connection part 3...Bulging part 4...Flange part
5...Embedded metal fittings 6...Crack 7...
・Spothole 8...Contact surface agent Patent attorney Nori Chika Ken Yudo Hirofumi Mitsumata No. 1 Figure 2 Figure 3 Figure 4 (A) Mouth Figure 5

Claims (1)

[Claims] An insulating spacer in which a plurality of embedded fittings are integrally cast on substantially the same circumference of a peripheral portion of an insulating main body, characterized in that at least one end surface of the embedded fittings is counterbore.