JPH0644875A - Resin mold vacuum valve - Google Patents

Abstract

PURPOSE:To make a flexible resin layer and an insulating reinforcing cylinder touch each other with high surface pressure so as to relieve thermal stress, and improve surface creeping insulation by forming a slant on a flexible resin layer on the periphery of a vacuum bulb, and forming a reverse slant on an insulting reinforcing cylinder on its periphery so as to fit the slant. CONSTITUTION:Both ends opening portions of an insulating cylinder 2 made of ceramic material are sealed airtightly by end plates so as to form a vacuum vessel 5. A pair of contacts 9 is provided inside the same so as to be free in connecting and disconnecting, so that a vacuum bulb is formed. A flexible resin layer 12, made of cyclic resin group epoxy resin as main material, is formed on the periphery of the bulb so as to form a slant on the outer surface thereof. An insulating reinforcing cylinder 10, molded with the bisphenol A type epoxy resin as the main material, is provided on the periphery of the resin layer 12. A reverse slant in correspondence to the slant of the resin layer 12 is formed on the inner surface thereof, so that both touch each other based on a stress cone method having high insulating performance. Thereby, it is possible to relieve thermal stress substantially relating to anti-crack performance and separation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin-molded vacuum valve having a reinforced outer creepage insulation.

[0002]

2. Description of the Related Art FIG. 4 is a sectional view showing an example of a typical vacuum valve. This vacuum valve 1 forms a vacuum container 5 by hermetically sealing the openings at both ends of an insulating cylinder 2 made of a ceramic material or the like with a fixed side end plate 3 and a movable side end plate 4.
The fixed shaft 6 is vacuum-tightly fixed to the fixed end plate 3,
The movable shaft 7 is attached to the movable side end plate 4 via a bellows 8, and the contacts 9 can be opened and closed by a driving force of an operation mechanism (not shown) while maintaining a vacuum.

In such a vacuum valve 1, the inside of the insulating cylinder 2 is made into a high vacuum having an excellent dielectric strength against a high voltage, and the arc generated when the contact 9 is opened and closed in the high vacuum is immediately extinguished. It interrupts the high voltage circuit. Therefore, since the contact 9 is opened / closed in a high vacuum, the electrode opening / closing distance required for interruption can be extremely shortened to interrupt the high voltage circuit. Therefore, the insulating cylinder 2 accommodating the electrodes of the vacuum valve 1 can be made compact with respect to a high voltage.

However, it is possible to make the insulating cylinder 2 compact by reducing the creepage distance on the outside so that, for example, when contaminants (moisture, dust, etc.) in the atmosphere adhere to the insulating cylinder 2, the withstand voltage decreases. External flashover is likely to occur. For this reason, it is known to integrally provide an insulating jacket on the outside of the vacuum container 5 by casting with an epoxy resin or the like in consideration of contamination conditions.

However, in such an integral structure, since the thermal expansion coefficient of the insulating jacket and the thermal expansion coefficient of the insulating cylinder 2 are different from each other, cracks may occur due to the generation of thermal stress, or the interface due to the impact force during opening / closing operation. Defects such as peeling occur and the reliability of the product is reduced. Even if the insulation jacket is good, the insulation cylinder 2 may be destroyed due to the generation of thermal stress. In particular, when the material of the insulating cylinder 2 is glass or the like, it becomes an important problem.

Therefore, as one of the structures for eliminating the above-mentioned problems such as cracks, an insulating reinforcing cylinder having a substantially outer creeping insulation length substantially made of epoxy resin or the like has been manufactured in advance by casting, and a vacuum valve is added thereto. There is one in which a flexible resin is poured and integrated after assembling 1.

FIG. 3 is a cross-sectional view showing an example of this structure, in which a rubber-like elastic body 11 made of polybutadiene, polyurethane, or the like is formed in the gap between the vacuum container 5 and the insulating reinforcing cylinder 10 for stress relaxation. .

[0008]

However, in such a resin-molded vacuum valve, the rubber-like elastic body 11 such as uncured polybutadiene or polyurethane is attached to the insulating reinforcing cylinder 10.
Volumetric shrinkage occurs when it is poured and cured, that is, when it changes from a liquid to a solid, as most plastics do. Therefore, residual strain is generated at the interface between the rubber-like elastic body 11 and the insulating reinforcing cylinder 10, and the heat cycle received when the equipment is operated or stopped may cause separation between the vacuum container 5 and the insulating reinforcing cylinder 10, or the worst case. In that case, cracks may occur in the insulating reinforcing cylinder 10. If cracks or peeling occur, dielectric breakdown will cause an accident. An object of the present invention is to provide a resin-molded vacuum valve that relieves thermal stress and improves creepage insulation.

[0009]

In order to achieve the above object, the present invention provides a vacuum valve having a pair of contact points which can be freely contacted and separated in a vacuum container and a vacuum valve which is formed on the outer circumference of the vacuum valve and is unidirectional. Since the flexible resin layer having an inclination and the insulating reinforcing cylinder formed on the outer periphery of the flexible resin layer and having an inclination in the opposite direction to the inclination of the flexible resin layer are formed, It is possible to make contact with the insulation reinforcing tube by a stress cone method having good insulation characteristics.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. It should be noted that the same components as those of the conventional one are designated by the same reference numerals and the description thereof will be omitted.

1 and 2 are sectional views of a resin-molded vacuum valve according to the present invention. In these figures, for example, a vacuum container 5 formed by hermetically sealing both end openings of an insulating cylinder 2 made of a ceramic material with end plates is provided with a pair of contact points 9 that can be contacted and separated. A flexible resin layer 12 having a hardness of 50 to 90 is formed on the valve 1 and the outer periphery of the main body of the vacuum valve 1 by a spring hardness test according to JAS K 6301 5.2 and a JAS A rubber hardness tester. The flexible resin layer 12 is provided with an inclination as shown in FIG. In addition, the insulation reinforcing cylinder 10 which is the other side of the attachment is also provided with a reverse inclination corresponding to the inclination of the flexible resin layer 12, and both are in contact with each other by a stress cone method having high insulation performance. Further, as the flexible resin layer 12, a cyclic resin group epoxy resin (for example, CX090 and CX28 manufactured by Chisso Corporation) is used.
9 mixture) as the main agent, and the curing agent as an acid anhydride (for example,
HHPA), a tertiary amine as a curing accelerator (eg BDM
A flexible resin layer obtained by adding an appropriate amount of an inorganic filler such as silica to the composition using A) and curing the mixture under specified conditions is used.

The insulating reinforcing cylinder 10 is mainly composed of a bisphenol A type epoxy resin (for example, Epicoat 828 manufactured by Shell Chemical Co., Ltd.), and an acid anhydride (for example, modified acid manufactured by Hitachi Chemical Co., Ltd.) as a curing agent. Silica fine powder (for example, Co., Ltd.) as a filler was added to a compound containing an anhydride-based curing agent HN2200.
Cast resin composition in which 50% or more of the entire mixture is mixed with a mixture of Kuramori Co., Ltd.'s Crystallite 5X) and glass fiber with an average fiber length of 50 μm (for example, Milled Fiber REV-7 from Nippon Sheet Glass Co., Ltd.) It is produced by adding a specified amount of a tertiary amine (for example, BDMA) as a curing accelerator to the product and casting.

Silicone grease, for example, High Vacuum Silcone Grease from Dow Corning Co., Ltd., is applied to the interface between the flexible resin layer 12 and the insulating reinforcing tube 10 thus obtained.
Is applied, and the vacuum valve mounting plate 13 and the embedded metal 16 of the insulating reinforcing cylinder 10 are integrated with bolts. At this time, the surface pressure
0.5 kgf / cm ² Adjust the tightening force as described above.
Next, the operation will be described.

The insulating reinforcing cylinder 10 and the flexible resin layer 12 are inclined so that they can come into contact with each other, and have a structure capable of increasing the surface pressure at the interface between them. For this reason, both can be contacted by the stress cone method with high insulation performance. In particular, the insulation reinforcement cylinder 10 and the flexible resin layer 12
The surface pressure at the interface with 0.5kgf / cm ² With the above, the insulation performance is further improved.

On the other hand, since the flexible resin layer 12 is soft,
Although it is freely deformed when attached and adheres to the insulation reinforcement cylinder 10,
By applying silicone grease or the like on both interfaces and integrating them, the adhesion is further improved and the reliability is further improved.

Since the insulating reinforcing cylinder 10 contains a large amount of glass fiber, it is excellent in crack resistance and mechanical properties, and is made of a casting material having high reliability not only as electric insulation but also as a structural material. It

Here, in order to explain the effect of the embodiment of the present invention, the conventional resin-molded vacuum shown in FIG. 3 in which the resin-molded vacuum valve according to the present invention and the rubber-like elastic body 11 are made of a polyurethane resinous resin compound is used. Table 1 shows the results of the impulse withstand voltage test of the valve after the thermal shock test. The thermal shock test is performed as one of the reliability tests of resin molded parts, and thermal stress generated by the difference in the thermal expansion coefficient between the flexible resin layer 12 and the insulating cylinder 2 when repeatedly subjected to thermal shock. By the influence of the above, it is investigated whether or not peeling between the members and cracks of the insulating reinforcing cylinder 10 occur.

The conditions of the thermal shock test used in the present invention are 98-
Immersion in warm water of 100 ° C. for 1 hour, taking out from the warm water, and immediately immersing in cold water of 0 to 2 ° C. for 1 hour are performed up to 10 cycles. The vacuum valve used in the present invention has a rated AC 24 kV class and an impulse withstand voltage standard of ± 125 kV or more after a thermal shock test.

As shown in Table 1, the impulse withstand voltage after the thermal shock test was measured at the interface between the rubber-like elastic body 11 and the insulating cylinder 2 of the vacuum valve body in the case of the vacuum valve using the conventional insulating reinforcing cylinder 10. I got tangled up. It is considered that this is because peeling occurred between the both due to repeated thermal shock.

On the other hand, the resin-molded vacuum valve according to the present invention sufficiently satisfies the specified impulse withstand voltage even after the thermal shock test, and the interface between the flexible resin layer 12 and the insulating cylinder 2 of the vacuum valve body and There is no flashover between the flexible resin layer 12 and the insulating reinforcing cylinder 10.

As described above, in the resin-molded valve of the present invention, since the outer periphery of the vacuum valve body is covered with the flexible resin layer 12, the thermal stress greatly related to the crack resistance and the peeling is greatly alleviated, and the operation of the equipment is reduced. It is also possible to prevent the occurrence of cracks against thermal shock when stopped.

Further, there is a proportional relationship between the surface pressure of the flexible resin layer 12 and the insulation reinforcing cylinder 10 and the insulation characteristic to some extent. It is better to increase the surface pressure as the voltage increases. By adjusting the hardness, the insulating cylinder 2 of the vacuum valve 1 can be applied to the one using glass.

[0023]

[Table 1]

[0024]

As described above, according to the present invention, the flexible resin layer formed on the outer periphery of the vacuum valve is inclined in one direction, and the insulation reinforcement formed on the outer periphery of the flexible resin layer is further provided. Since the cylinder is provided with a reverse inclination so as to match the inclination of the flexible resin layer, the flexible resin layer and the insulation reinforcing cylinder can be brought into contact with each other by the surface pressure, and creeping insulation can be improved.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a resin mold vacuum valve of the present invention.

FIG. 2 is a diagram for explaining [FIG. 1].

FIG. 3 is a sectional view of a conventional resin-molded vacuum valve.

FIG. 4 is a cross-sectional view of a typical vacuum valve.

[Explanation of symbols]

1 ... Vacuum valve, 10 ... Insulation reinforcing tube, 12 ... Flexible resin layer.

Claims (3)

[Claims] 1. A vacuum valve having a pair of contact points which can be freely contacted and separated in a vacuum container, and a vacuum valve formed on the outer periphery of the vacuum valve,
A flexible resin layer having an inclination in one direction, and an insulating reinforcing tube formed on the outer periphery of the flexible resin layer and having an inclination in the opposite direction to the inclination of the flexible resin layer. Characteristic resin-molded vacuum valve. 2. The interface between the flexible resin layer and the insulating reinforcing cylinder
0.5 kgf / cm ² The resin-molded vacuum valve according to claim 1, wherein the resin mold vacuum valve is integrated by applying the above surface pressure. 3. The resin-molded vacuum valve according to claim 1 or 2, wherein silicone grease is formed at the interface between the flexible resin layer and the insulating reinforcing cylinder to integrate them.