JPH06231661A - Resin molded vacuum bulb and its manufacture - Google Patents

Abstract

PURPOSE:To enhance productivity in manufacture, and concurrently enhance electrical insulation by forming a stress relaxing layer around the outer circumference of a vacuum bulb where the layer is made of resin hardened by ultra violet ray. CONSTITUTION:In order to form a resin layer as a stress relaxing layer (UV hardening resin) 13, which is made of resin hardened by ultra violet ray, around the outer circumference of a vacuum bulb, the vacuum bulb is rotated by a variable speed motor, and let UV hardening resin stored in a resin tank, drop down therein. And ultra violet ray generated by a light source are locally irradiated thereon through a light inlet provided for a light shielding plate. This constitution thereby can prevent even a resin feed section fed from resin tank from being hardened. In this case, since the layer 13 acting as a stress relaxing layer made of UV hardening resin, is formed around the outer circumference of the vacuum bulb, and an insulation reinforcing cylinder 10 is also formed over the outer circumference of the layer 13, electrical insulation can thereby be enhanced. Furthermore, productivity can also be enhanced, because the bulb is locally irradiated by ultra violet ray.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin mold vacuum valve and a method for manufacturing the same.

[0002]

2. Description of the Related Art FIG. 3 is a sectional view of a typical vacuum valve.

In the figure, the vacuum valve 1 is an insulating cylinder 2.
Both end openings are airtightly sealed by the fixed side end plate 3 and the movable side end plate 4 to form a vacuum container 5, and the fixed shaft 6 is fixed to the fixed side end plate 3 in a vacuum airtight manner. 7 is attached to the movable side end plate 4 via a bellows 8 so that the contact 9 can be opened and closed while the vacuum is maintained.

Such a vacuum valve 1 utilizes a high vacuum having an excellent dielectric strength against a high voltage in the insulating cylinder 2 to immediately extinguish an arc generated when the contact 9 is opened and closed in the high vacuum. It makes an arc and interrupts the high voltage circuit.

Since the vacuum valve 1 opens and closes the contact 9 in a high vacuum in this manner, the high-voltage circuit can be interrupted by shortening the interelectrode distance required for interruption. Therefore, there is an advantage that the insulating cylinder 2 accommodating six electrodes of the vacuum valve can be made compact.

However, the fact that the insulating cylinder 2 can be made compact means that the outer creepage insulation distance is shortened, and when contaminants (moisture, dust, etc.) in the atmosphere adhere, the withstand voltage decreases. External flash is likely to occur. For this reason, it is known to provide an insulating outer cover on the outside of the vacuum container 5 with epoxy resin or the like in consideration of the stain condition.

Further, when the insulating envelope is directly formed on the surface of the vacuum container 5, cracks may be generated due to the thermal stress generated due to the difference in thermal expansion coefficient between them, or the interface may be separated due to the impact force during opening / closing operation. May occur, and the reliability as a product may be reduced. For this reason,
As one of the structures to eliminate the above-mentioned problems such as cracks and peeling, an insulation reinforcement cylinder having a substantially outer creeping insulation length substantially made of epoxy resin or the like is manufactured by casting in advance, and this is incorporated into a vacuum valve. There is something like this.

FIG. 4 is a cross-sectional view showing this structure, in which a rubber-like elastic body 11 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. It is said to be a potting method.

On the other hand, on the contrary, after forming a stress relaxation layer by a rubber-like elastic body 11 such as a flexible epoxy resin, polybutadiene or polyurethane on the outer periphery of the vacuum valve by casting in advance, epoxy having excellent mechanical properties is formed. There is also a method of molding with a cast material.

In this case, a prefabricated insulation reinforcing cylinder 10,
Alternatively, the rubber-like elastic body 11 is processed by using a casting mold. The casting mold has a mold release agent applied to the mold surface to improve the mold release property of the molded product.
10. A film of a release agent is also formed on the surface of the rubber-like elastic body 11. Currently, the main components of the release agent used are silicone compounds and fluorine compounds, and they have water repellency and prevent adhesion with other materials.

Therefore, when the resin-molded vacuum valve is manufactured by the potting method using the prefabricated insulating reinforcing cylinder 10, the treatment of the bonding surface between the insulating reinforcing cylinder 10 and the rubber elastic body 11 is very important. At present, after removing the release agent component by washing with an organic agent or the like, the material for forming the rubber-like elastic body 11 is poured after being roughened by sandblasting or the like and washed again with an organic solvent or the like. The same applies to the case where the rubber-like elastic body 11 is formed on the outer circumference of the vacuum valve in advance and is then molded with an epoxy-based casting material having excellent mechanical properties. Since the release agent adheres to the surface, it is washed with an organic solvent or the like, roughened with sandpaper, washed again with an organic solvent or the like, and then molded with an epoxy casting material having excellent mechanical properties.

[0012]

As described above, the manufacture of the resin-molded vacuum valve, especially the boundary surface where the above-mentioned materials are bonded, requires great care and requires a lot of trouble. In the unlikely event that a peeled portion is present in the adhesive portion, electric field concentration occurs and corona discharge characteristics are significantly reduced, and electrical insulation properties such as a reduction in dielectric breakdown strength are deteriorated.

In the conventional manufacturing method, the rubber-like elastic body is used.
A mold is required to form 11 and it takes several hours for the material to cure. Also, when molding with an epoxy-based casting material with excellent mechanical properties, surface treatment is required, etc.
Not suitable for mass production. An object of the present invention is to provide a highly productive manufacturing method and a resin mold vacuum valve having excellent electrical insulation.

[0014]

In order to achieve the above object, according to a first aspect of the invention, a vacuum is provided in which a pair of electrodes which can be contacted and separated is disposed in a vacuum container in which both ends of an insulating container are hermetically sealed. The gist of the present invention is to have a valve, a stress relaxation layer formed on the outer circumference of a vacuum valve and made of a resin that is cured by ultraviolet light, and an insulating layer molded on the outer circumference of the stress relaxation layer.

According to the second aspect of the invention, a vacuum valve having a pair of electrodes that can be contacted and separated from each other is rotated in a vacuum container formed by hermetically sealing both ends of an insulating container to supply a resin which is cured by ultraviolet rays. However, the gist is to partially irradiate ultraviolet rays to manufacture.

[0016]

With such a structure, in the first invention, the stress relaxation layer formed on the outer periphery of the vacuum valve is made of a resin which is cured by ultraviolet rays. Therefore, the stress relaxation layer can be formed without using a mold. And the curing time of the resin can be shortened.

In the second aspect of the invention, in order to form the stress relaxation layer on the outer periphery of the vacuum valve, the vacuum valve is rotated and ultraviolet rays are partially irradiated while supplying the resin which is cured by the ultraviolet rays. It is possible to form the stress relaxation layer without using, and it is possible to prevent the resin supply portion from being cured.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a view for explaining a method of manufacturing a resin-molded vacuum valve showing an embodiment of the present invention, and FIG. 2 is a sectional view of the resin-molded vacuum valve obtained in FIG. It should be noted that the same components as those in the related art are designated by the same reference numerals and the description thereof will be omitted.

In these figures, a resin that is cured by ultraviolet rays (hereinafter referred to as a stress relaxation layer on the outer periphery of the vacuum valve 1)
In order to form the layer 13 called UV curable resin, the vacuum valve 1 is rotated by a variable speed motor (not shown), and the UV curable resin 12 injected into the resin tank 18, for example, an acrylic UV curable resin (UVU1002: Sanyo Kasei). Industrial Co., Ltd.)
Light from the light inlet 17 provided in the light shield plate 15
The ultraviolet rays generated in 16 are locally irradiated. By doing so, it is possible to prevent the resin supply portion supplied from the resin tank 18 from being cured. Further, the thickness of the UV curable resin layer 13 can be adjusted by the thickness adjusting jig 14.
At this time, the UV curable resin 12 may be first formed on the outer circumference of the vacuum valve 1 by coating or dipping, and then the vacuum valve 1 may be rotated to locally irradiate ultraviolet rays.

The vacuum valve thus obtained is assembled in a mold (not shown) to form the insulating reinforcing cylinder 10,
Preheated under the specified conditions in advance, using 100 parts by weight of bisphenol A type epoxy resin and 85 parts by weight of modified acid anhydride curing agent as a matrix, 150 parts by weight of silica powder with an average particle size of 1.0 μm or less as a filler, fiber length of 30 ~ 100 μm short glass fiber
Molding is performed with a casting material in which a specified amount of a curing accelerator is added to a resin composition mixed with 250 parts by weight. After molding as described above, primary curing is performed under specified conditions, and then mold release is performed, and secondary curing is further performed to completely cure.

Next, the resin-molded vacuum valve 19 according to the present invention shown in FIG. 2 manufactured as described above, the insulating reinforcing cylinder 10 shown in FIG. 4 and the rubber-like elastic body 11 of polyurethane resin are used. When the vacuum valve and the impulse withstand voltage test were performed after the thermal shock test, the results shown in the following table were obtained.

The thermal shock test is carried out as one of the reliability tests of resin molded products, and the thermal expansion coefficient is repeatedly applied to the insulating reinforcing cylinder 10 or the rubber-like elastic body 11 and the insulating cylinder 2 so that the thermal expansion coefficient is different. The purpose of this is to investigate whether or not there is a peeling between each other and the occurrence of cracks in the insulating reinforcing cylinder 10 due to thermal stress generated from the.

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 set as one cycle up to 10 cycles. The vacuum valve used in the present invention is for a rating of 6.9 kV, but the standard of impulse withstand voltage after the thermal shock test is ± 85 kV or more.

[0024]

[Table 1] As shown in Table 1, the impulse withstand voltage after the thermal shock test is
In the case of the resin-molded vacuum valve in FIG. 4, 2 out of 5 pieces were broken. On the other hand, it is understood that the resin-molded vacuum valve according to the present invention sufficiently satisfies the specified impulse withstand voltage even after the thermal shock test, and there is no peeling at the bonded portion.

As described above, according to this embodiment, the UV curable resin is cured only in the portion irradiated with ultraviolet rays, and the curing time is completed within a few seconds by the irradiation of ultraviolet rays. Therefore, the uncured resin formed on the surface of the vacuum valve is not cured. UV curable resin cures before it drips, so UV curable resin layer 1 does not require a mold.
3, that is, the stress relaxation layer can be formed. Therefore, since there is no substance that inhibits adhesion such as a release agent at the interface of the obtained UV curable resin layer 13, the adhesion of the insulating reinforcing cylinder 10 containing the silica powder and the glass short fibers at a high density is also possible. It is improved, and the processing such as sandblasting becomes unnecessary.

Further, the elastic modulus of the UV curable resin 12 is 150 to 30.
0 kgf / mm ² On the other hand, the elastic modulus of the casting material used for the insulation reinforcing cylinder 10 is 1500 to 1600 kgf / mm ² Since the UV curable resin 12 is soft, its function as a stress relaxation layer can be remarkably improved, and the crack resistance of the resin mold vacuum valve 19 can be improved.

[0027]

As described above, according to the first aspect of the present invention, the stress relief layer made of a resin which is cured by ultraviolet rays is formed on the outer periphery of the vacuum valve, and the insulating layer is molded on the outer periphery of the stress relief layer. The electrical insulation can be improved.

According to the second aspect of the invention, since the vacuum valve is rotated and the resin which is hardened by ultraviolet rays is supplied and the resin is partially irradiated with ultraviolet rays for manufacturing, the productivity can be improved.

[Brief description of drawings]

FIG. 1 is a diagram for explaining an example of a method for manufacturing a resin-molded vacuum valve according to the present invention.

FIG. 2 is a sectional view showing an embodiment of a resin-molded vacuum valve of the present invention.

FIG. 3 is a sectional view of a typical vacuum valve.

FIG. 4 is a sectional view of a conventional resin-molded vacuum valve.

[Explanation of symbols]

 5 ... Vacuum container, 10 ... Insulation reinforcing tube, 13 ... UV curable resin layer.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshio Shimizu 1 Toshiba Town, Fuchu City, Tokyo Toshiba Corporation Fuchu Factory

Claims (4)

[Claims] 1. A vacuum valve having a pair of electrodes which can be separated from each other in a vacuum container in which both ends of an insulating container are hermetically sealed, and a resin which is formed on the outer periphery of the vacuum valve and is cured by ultraviolet rays. A resin-molded vacuum valve having a stress relaxation layer made of and an insulating layer molded around the stress relaxation layer. 2. The resin-molded vacuum valve according to claim 1, wherein the stress relaxation layer is an acrylic resin. 3. The resin-molded vacuum valve according to claim 1, wherein the insulating layer contains silica powder and glass short fibers. 4. A vacuum valve provided with a pair of electrodes which can be contacted and separated from each other is rotated in a vacuum container in which both ends of an insulating container are hermetically sealed, and a resin which is cured by ultraviolet rays is partially supplied while being supplied. A method for manufacturing a resin-molded vacuum valve, which is characterized in that it is irradiated with ultraviolet rays.