JPS5929386A - Insulating terminal for electric device - Google Patents

Abstract

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

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to improvements in insulated terminals used in electrical equipment such as lightning arresters.

[Technical background of the invention and its problems]

2. Description of the Related Art Conventionally, in electrical equipment such as lightning arresters, insulated terminals have been used to electrically connect electrodes attached to the ends of the elements to the outside.

As shown in Fig. 1, this insulated terminal is composed of a conductor 1 made of metal and an insulator 2 that covers the outer periphery of the conductor 1. After manufacturing the conductor 1 part, the insulator 2 is cast (molded).
It is often made by

Naturally, in such an insulated terminal, the conductor 1 and the insulator 2
Since the linear expansion coefficients of the two terminals are different, residual stress is already generated when the insulated terminal is manufactured by casting. In addition, during actual use, thermal stress is repeatedly applied due to temperature changes in the arrester element and ambient temperature changes. Therefore, if the generated stress is high, there is a risk of thermal fatigue causing delamination or breakage at the interface between the conductor 1 and the insulator 2, leading to a decrease in the reliability of the lightning arrester. become.

[Purpose of the invention]

The present invention was made in order to solve the above-mentioned problems, and its purpose is to provide a highly reliable terminal for electrical equipment that has high strength against residual stress generated during manufacturing and thermal fatigue applied during use. It is about providing.

[Summary of the invention]

In order to achieve the above object, the present invention focuses on the fact that the thermal stress generated in the above-mentioned insulated terminal is greatest at the insulator end, and reduces the thickness of the insulator end near the conductor end. It is characterized by

[Embodiments of the invention]

The present invention will be explained below with reference to an embodiment shown in the drawings. FIG. 2 is a sectional view showing an example of the structure of an insulated terminal for a lightning arrester according to the present invention. Claw 9: As shown in the figure, this insulated terminal is made by casting an insulator 3 whose end part is smaller in thickness than other thickness dimensions so as to cover the outer periphery of the conductor 4 except for the axial ends. In other words, a convex portion is formed near the contact surface between the end of the insulator 3 and the end of the conductor 4.

If the insulated terminal for a lightning arrester has such a configuration, the thickness of the end of the insulator 3 that comes into contact with the conductor 4 is /J't small, so the restraining force of the insulator 3 on the conductor 4 becomes small.
, an insulator 3 and a conductor 4 are formed. As a result, there is no risk of peeling or destruction occurring at the contact surface between the insulator 3 and the conductor 4 as in the past, and as a result, residual stress generated during manufacturing can be reduced.
It is possible to obtain an extremely reliable insulated terminal that has high strength against thermal fatigue during use.

Figures 3 and 4 show the thermal stress distribution in the radial and circumferential directions, with the horizontal axis representing the distance from the insulator end face (
x/d), and the vertical axis shows the stress ratio (r/σro) and (σθ/σθ0), respectively. In the figure, A is the conventional insulated terminal shown in FIG. 1, and B is the insulated terminal of this embodiment. The figure shows that the present insulated terminal B has improved thermal stress in both the radial direction and the circumferential direction compared to the conventional terminal A.

It should be noted that the present invention is not limited to the above embodiments, but can also be implemented as follows.

(&) As shown in Fig. 5, it may be composed of an insulator 5 and a conductor 4 with four parts formed at the end, and the thermal stress distribution in this case is as shown in C in Figs. 3 and 4. It will be like this.

(b) As shown in Figure 26, a cushioning material 7 may be inserted into a part (or all) of the contact surface between the insulator 6 and the conductor 4, and the thermal stress distribution in this case is the same. It will look like D in FIGS. 3 and 4.

In addition, the present invention can be modified and implemented in various ways without changing the gist thereof, such as application to electrical equipment other than lightning arresters.

〔Effect of the invention〕

As explained above, according to the present invention, the thickness of the end portion of the insulator is reduced, thereby providing highly reliable insulation for electrical equipment that has strength against residual stress generated during manufacturing and thermal fatigue applied during use. Terminals can be provided.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing a conventional insulated terminal for lightning arresters, Fig. 2 is a sectional view showing an embodiment of the present invention, and Figs. 3 and 4 show thermal stress distribution in the radial and circumferential directions. 5 and 6 are cross-sectional configuration diagrams showing other embodiments of the present invention. 1.4...Conductor, 2,3,5,6...Insulator, 7.
・Cushion material. Applicant's agent Patent attorney Takehiko Suzue Figure 1 f153 Figure 0 f30.6 0.4 Q2 0 Leaky furnace d Figure 4 371- Figure 5

Claims (2)

[Claims] (1) An insulator is cast to cover the outer periphery of the conductor except for the ends in the axial direction, and the thickness of the ends of the insulator near the ends of the conductor is reduced. Insulated terminals for electrical equipment. (2) The insulated terminal for electrical equipment according to claim (1), wherein a convex portion or a concave portion is formed near the contact surface of the insulator end with the conductor end.