JPS596450B2 - vacuum switch - Google Patents

Description

[Detailed description of the invention] The present invention relates to a vacuum switch.

High-voltage, large-capacity vacuum switches have a breakdown voltage of -
The kV77 is long due to its length, and since it is necessary to connect and disconnect between the electrodes in half a cycle or one cycle, the speed increases and the impact force increases significantly.

Therefore, if the vacuum switch alone were to have a structure that could withstand this, it would be extremely expensive.

In addition, the creepage distance must be increased to withstand flashing when the external creepage is contaminated.

Conventionally, in order to increase the external creepage distance, the vacuum container of the vacuum switch was usually directly covered with a resin molded body.
The casting temperature of the resin and the Tg (glass transition temperature) of the casting material are higher than the operating temperature of the equipment, and the operating temperature is expected to fluctuate by several tens of degrees, so thermal stress due to the relationship between the casting material and the vacuum port and torque. occurs and the bottle is damaged.

A type in which a vacuum bottle is molded with a flexible resin causes the same problems as the above-mentioned type; for example, even if it can withstand only thermal stress, there is a strong possibility that it will break due to the impact force caused by the insertion and disconnection of electrodes.

Furthermore, in the type where the vacuum bottle is molded with a foam cushion in order to alleviate this thermal stress, the use of foam has a negative effect on the lifespan of the battery due to the high pressure. It is necessary to provide a shield to alleviate the electric field.

Furthermore, this evening, Eve wrapped the vacuum switch bottle loosely in a thick cushion, so the tightening force was either very small or almost impossible.

If the tightening force is too large, the bottle will be destroyed as described above, but if the tightening force is too small, the flashover value through the interface will be low.

A low flashover value requires a longer interface distance, which results in a larger vacuum switch.

Furthermore, if the tightening pressure of the cushion is low, vibrations such as opening and closing of the electrodes will cause play between the cushion and the molded body.

Therefore, the present applicant has proposed a product in which a butadiene rubber coating layer is provided in order to alleviate thermal stress so that a suitably large tightening pressure can be applied, and has previously filed a patent application.

According to this, it is sufficiently effective in increasing the flash fault voltage at the glass cylinder interface and reducing its variation, but...
In order to have an appropriate clamping pressure in a vacuum switch with a
There are limitations on the thermal expansion coefficient and structural dimensions of the composition, and on the curing conditions when forming the above-mentioned coating layer by casting, making it difficult to obtain the necessary electrical and mechanical properties.

Therefore, in view of the above-mentioned points, the present invention provides a vacuum switch having a structure in which a cushion layer is provided between an insulating tube and a vacuum switch. In order to obtain tightening force, a stretchable bag-shaped insulating material is placed inside the cushion rubber layer, and liquid rubber is press-fitted into it and hardened to form a material that can be used indoors or outdoors with excellent mechanical and electrical properties. The purpose is to provide a vacuum switch applied to.

The present invention will be explained in detail below based on illustrated embodiments.

FIG. 1 is a side vertical sectional view of a vacuum switch according to the present invention.

In the figure, the vacuum switch 1 is, for example, a 36KV type, and its structure is as follows: an end plate 4 disposed on the fixed electrode 2 side, a movable electrode 3
An insulating cylinder 7 made of a glass material with a metal member 6 sealed at the middle part and the end part is provided between the side end plate 5 and the vacuum switch 1 has a fixed electrode 2 and a movable electrode 3. Contact point 2a
.

An intermediate shield 8 is disposed near 3a, and this shield 8 is supported and fixed to the intermediate portion of the cylinder 7 by a support member 8a.

9 is a bellows. Further, a reinforcing plate 10 is provided on the end plate 4 of the vacuum switch 1.

The vacuum switch 1 is covered with an insulating tube 12 with an appropriate space a outside the switch 1.

In the space a, the surface of the insulating cylinder 7 of the vacuum switch 1,
A cushion rubber layer 11 is provided that constitutes a covering layer for the end plates 4 and 5 and the plate-like portions of the reinforcing plate 10. Furthermore, in the cushion rubber layer 11, a bag-shaped insulating material having elasticity is provided. Object 16 is buried.

The insulating pipe 12 is mounted on a fixed substrate 13 with an embedded metal fitting 14. It is fixed with bolts 15.

When installing the cushion rubber layer 11, the bag-shaped insulator 16, and the insulating tube 12 in the vacuum switch 1, the bag-shaped insulator 16 with the press-fit tube part 17 at the end is inserted into the insulator tube 12, and the end A vacuum switch 1 provided with a reinforcing plate 10 is inserted and arranged concentrically on the plate 4.

At this time, the outer circumferential surface of the glass cylinder 7 of the vacuum switch 1 and the inner circumferential surface of the insulating tube 12 form an appropriate distance, and that part is placed in the space a, and the bag-shaped The inner and outer diameters of the bag-shaped insulator 16 and the inner diameter of the insulator tube 11 are adjusted so that the insulator 16 forms an appropriate distance between the outer circumferential surface of the insulating cylinder 7 and the inner circumferential surface of the insulator tube 12. The dimensions have been increased.

The insulating tube 12 is made of porcelain or, for example, an average strength of 8 to 8 ky.
/Tomo2, longitudinal elastic modulus 1000kg/Tomo2, expansion coefficient 4
An epoxy resin having a temperature of 10"/°C is used.

The outer peripheral surface of the insulating pipe 12 is provided with pleats to prevent sweat loss.

After the vacuum switch 1 and the bag-shaped insulator 16 are placed inside the insulating tube 12, the inside of the bag-shaped insulator 16 is evacuated, and a liquid rubber, for example, a liquid rubber having a water group at the end is placed in the space a. Polybutadiene or its copolymer and ordinary isocyanates are mixed in equivalent ratio, defoamed, and then injected.

In this case, the liquid rubber is injected through the ring-shaped gap 18 formed around the end plate 5 of the vacuum switch 1, and left at room temperature or heated to harden.

This rubber liquid is cured by the main chain extension reaction and crosslinking reaction, and becomes rubbery to form the cushion rubber layer 11.

After the cushion rubber layer 11 is formed in a rubber-like manner in this way, liquid rubber made of the same material as the rubber liquid or a different material and similar to the rubber liquid is applied to the bag-shaped insulator 16 at the required pressure. Press in until the

In this case, the press-fit tube section 17 is made to protrude outward from the gap 18, and the rubber liquid is injected through the press-fit tube section 17, and then left at room temperature or heated to harden.

Then, the rubber liquid hardens and becomes rubbery in the same manner as in the case of the cushion rubber layer 11 described above.

The amount of liquid rubber press-fitted into the space a and the inside of the bag-shaped insulator 16 is such that the pressure-fitted tube portion becomes an injection port by press-fitting it to a value that requires both external pressure to the vacuum switch 1 and internal pressure to the insulating tube 12. 17 is sealed and cured under predetermined conditions, for example at room temperature.

The above-mentioned required pressure means that when the liquid rubber hardens, it tightens the vacuum switch 1 and presses the insulating tube 12 outward, so that there is no gap at the interface even if the temperature (usage atmosphere) goes up or down due to the difference in their thermal expansion coefficients. This refers to the pressure at which the vacuum switch 1 or the insulating tube 12 is not destroyed, and there is no displacement of the interface.

The insulating pipe 12 is made of porcelain when used outdoors or in a similar location, and is made of resin molded when used indoors. By changing it, it can be adapted to each place of use.

The bag-shaped insulator 16 is made of a material having electrical insulation properties and appropriate elasticity, such as elastic rubber or soft resin, and its structure is illustrated in FIG. 2.

The one shown at A in the figure is a pipe 1 with insulation and elasticity.
The upper end of the pipe 16' is sealed and the lower end is opened to form the above-mentioned press-fit pipe section 17.

The one shown in FIG. B is formed of a pipe 16' as shown in FIG. 'The upper end of the pipe is bent downward to form a discharge pipe part 19.

This discharge pipe part 19 is similar to the press-fit pipe part 17, and has the above-mentioned gap 1.
8, when injecting liquid rubber from the press-fitting pipe section 17, the internal air is discharged to assist the injection of the liquid rubber, and after a predetermined amount of liquid rubber has been injected, the opening is sealed, and the press-fitting is then carried out. This is applied to the case where liquid rubber is further press-fitted from the pipe portion 17 to a required pressure value.

The one shown in Figures A' and A'1 is formed into a double cylinder by combining an insulating and stretchable inner cylinder 16'' and an outer cylinder 16''/, with a ring-shaped space between the two cylinders. is formed by sealing an upper end and a lower end, and a press-fit tube portion 1γ is provided at the lower end.

The one shown in Figure A' has the same configuration as the one shown in Figure A'tA'1 above, but is formed with a smaller height, but is made up of multiple pieces with appropriate spacing in the vertical direction. are connected by a connecting pipe 20.

The one shown in Figure B' has the same structure as the one shown in Figures A' and A'1 above, but the difference is that it is equipped with the discharge pipe section 19 shown in Figure B above. be.

The one shown in Figure B" has the same structure as the one shown in Figure A" above, but the difference is that it is equipped with the discharge section 19 shown in Figures B and B' above. .

As explained above, according to the vacuum switch according to the present invention, the vacuum switch 1 is press-fitted into the space a between the vacuum switch 1 and the insulating tube 12 in order to relieve thermal stress so that an appropriate tightening force is applied. In the cushion rubber layer 11 provided, a bag-shaped insulator 16 having elasticity is further disposed, and liquid rubber is press-fitted into the bag-shaped insulator 16 to a required pressure value and cured. The cushion rubber layer 11 is moved to the glass cylinder 7 of the vacuum switch by applying appropriate pressure and the pressure of the hardened rubber layer inside the bag-shaped insulator 16.
The vacuum switch 1 and the insulating tube 12 have the necessary tightening force and adhesion to the insulating tube 12, and the vacuum switch 1 and the insulating tube 12 are in close contact with each other, and are strong against static forces and impact forces when the electrode is turned on and off, and do not vibrate. By being able to absorb the material sufficiently, there will be no interfacial dislocation, and not only the mechanical strength but also the electrical properties (flash fault value) of the interface can be improved.

In addition, the sign and magnitude of the pressure applied to the vacuum switch and the insulating tube depend on the thermal expansion coefficient and structural dimensions of the vacuum switch, the cushion rubber layer, the bag-shaped insulator, the insulating tube, and the curing conditions of both liquid rubbers. , since the limitations of the conventional example to obtain the necessary electrical and mechanical properties are eliminated, the above-mentioned necessary characteristics can be easily obtained, and furthermore, there is no foaming rubber etc. as in the conventional example, so there are no voids. There is no deterioration of electrical properties due to partial discharge, and there is no need for surface treatment to improve the adhesion between the outer circumferential surface of the glass cylinder, the inner circumferential surface of the insulating tube, and the cushion rubber layer, so the number of processing steps can be reduced. There are advantages.

[Brief explanation of drawings]

FIG. 1 is a side vertical cross-sectional view of the vacuum switch according to the present invention, and FIG. FIG. 2 A1 is a side vertical sectional view of the bag-shaped insulator shown in FIG. 2 A'. 1... Vacuum switch, 11... ... Cushion rubber layer, 12 ... Insulating pipe, 16 ...
...Stretchable bag-shaped insulator, 20...Connection pipe, a...Space.

Claims (1)

[Claims] 1. A cushion rubber layer constituting the coating layer of the vacuum switch is provided in the space between the insulating tube and the vacuum switch, and a bag-shaped insulator having elasticity is provided in the cushion layer. 1. A vacuum switch, characterized in that the vacuum switch is formed by press-fitting liquid rubber into the bag-shaped insulator up to a required pressure value and hardening it. 2. The vacuum switch according to claim 1, wherein the bag-shaped insulator is formed by spirally winding an insulating and stretchable pipe. 3. The vacuum switch according to claim 1, wherein the bag-shaped insulator is made of a stretchable double cylinder. 4. The bag-shaped insulator is formed by connecting a plurality of stretchable double cylinders with the same diameter coaxially in a connected pipe. Claim 1
Vacuum switch described in section.