JP2013030368A - Resin-cast article and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve adhesiveness between an insulating layer cast with an epoxy resin and an electric member embedded therein.SOLUTION: There is provided a resin-cast article comprising: a main insulating layer 11 cast with a casting resin; an electric member, such as metallic caps 4, 7, which is embedded in the main insulating layer 11 and is provided in the periphery of sealing metallic parts 2, 3 of a vacuum valve 1, to which sandblasting has been performed; and insulating films 6, 10 provided on a sandblasted surface of the metallic caps 4, 7 and formed of an insulating paint, a heat distortion temperature of which is lower than that of the main insulating layer 11.

Description

  Embodiments described herein relate generally to a resin cast product in which an electric member such as a vacuum valve is embedded in an insulating layer, and a method for manufacturing the same.

  2. Description of the Related Art Conventionally, in a vacuum valve having a pair of contactable contacts, an insulating layer is formed by casting a resin such as an epoxy resin on the outer periphery, and external insulation reinforcement is performed. In this case, the metal fitting for electric field relaxation is provided in the sealing fitting of the vacuum valve, and a sandblasting treatment or a conductive paint coating treatment is performed so as to adhere well to the insulating layer (for example, , See Patent Document 1).

  However, as the capacity of the vacuum valve increases, the temperature rise due to the energization current increases, and a stronger bond is required. That is, since the thermal stress generated from the difference in the linear expansion coefficient between the epoxy resin and the metal cap and the temperature difference increases, the adhesiveness must be improved so as to withstand it. In addition, when adhesion cannot be endured, peeling or the like occurs and insulation deterioration occurs.

JP 2005-276472 A

  A problem to be solved by the present invention is that a resin casting product that can improve the adhesion between an electric member and an insulating layer in an electric member such as a vacuum valve provided with a metal cap embedded in the insulating layer, and its manufacture It is to provide a method.

  In order to solve the above-mentioned problems, a resin cast product according to an embodiment includes a main insulating layer cast with a casting resin, an electric member embedded in the main insulating layer and subjected to sandblasting, and the electric And an insulating coating provided with an insulating paint having a thermal deformation temperature lower than that of the main insulating layer.

Sectional drawing which shows the structure of the resin casting product which concerns on Example 1 of this invention. The principal part expanded sectional view which shows the structure of the resin casting product which concerns on Example 1 of this invention. The figure which shows the manufacturing method of the resin casting based on Example 1 of this invention. Sectional drawing which shows the structure of the resin casting product which concerns on Example 2 of this invention.

  Embodiments of the present invention will be described below with reference to the drawings.

  First, a resin cast product according to Example 1 of the present invention will be described with reference to FIGS. FIG. 1 is a cross-sectional view showing a configuration of a resin cast product according to Embodiment 1 of the present invention according to Embodiment 1 of the present invention, and FIG. 2 shows a configuration of the resin cast product according to Embodiment 1 of the present invention. The principal part expanded sectional view shown, FIG. 3 is a figure which shows the manufacturing method of the resin casting based on Example 1 of this invention. In the resin cast product, an electric member embedded in the insulating layer will be described using a vacuum valve.

  As shown in FIG. 1, a fixed-side sealing metal fitting 2 and a movable-side sealing metal fitting 3 are sealed at both ends of a vacuum insulating container 1 of a vacuum valve having a pair of contactable and separable contacts. Around the fixed-side sealing fitting 2, a hook-shaped fixed-side metal cap 4 is provided and fixed to the fixed-side energizing shaft 5. The fixed-side metal cap 4 is provided with a fixed-side insulating coating 6 for improving adhesiveness described later.

  A hook-like movable metal cap 7 is also provided around the movable sealing metal fitting 3 and is fixed to the resin intrusion prevention tube 8. A movable movable energizing shaft 9 is inserted into the resin intrusion prevention pipe 8. Similarly to the fixed side, the movable side metal cap 7 is provided with a movable side insulating coating 10. A main insulating layer 11 cast with epoxy resin is provided on the outer periphery of the vacuum valve 1 and the metal caps 4 and 7. That is, in the main insulating layer 11, the vacuum valve 1 and the metal caps 4 and 7 that are electric members are embedded. At both ends of the insulating layer 11, tapered interface connecting portions 11a and 11b for connecting to other members are provided.

  Next, a manufacturing method is demonstrated with reference to FIG. 2, FIG.

  As shown in FIGS. 2 and 3, first, the metal caps 4 and 7 made of a copper material are subjected to sand blasting to roughen to a surface roughness Rz of 30 to 50 μm (st1). After this is washed with acetone (st2) and dried (st3), an insulating coating is applied, for example, by brushing, and insulating coatings 6 and 10 having an insulation thickness of several tens to several hundreds of μm are provided (st4). The surfaces of the insulating coatings 6 and 10 are smoother than the surfaces of the metal caps 4 and 7 as shown.

  Here, the insulating paints are glycidyl ether type epoxy resins such as bisphenol A type epoxy resin and bisphenol F type epoxy resin, cyclic aliphatic epoxy resins such as bis adipate, and hexahydrophthalic acid glycidyl ester type epoxy resins. Further, a curing agent such as an aliphatic dicarboxylic acid such as succinic acid or dimer acid, an alicyclic dicarboxylic acid such as hexahydrophthalic acid, or an aromatic dicarboxylic acid such as phthalic acid or isophthalic acid is mixed. If the mixing ratio of the curing agent is smaller than that of the main agent, the heat distortion temperature can be suppressed lower than that of the main insulating layer 11 and the adhesiveness can be improved. The insulating paint can be diluted with acetone, methanol or the like.

  Next, dripping after the application of the insulating paint is prevented, and pre-curing is performed at about 100 ° C., which is lower than the heat deformation temperature of the main insulating layer 11 (st5). The heat deformation temperature after pre-curing is about 60 ° C., which is lower than the heat deformation temperature 120 to 150 ° C. of the main insulating layer 11 described later. Pre-curing means that the surface is cured and is cured at a temperature lower than the curing temperature of the main insulating layer 11.

  Next, the vacuum valve to which the metal caps 4 and 7 are attached is set in a casting mold (st6), casting is performed (st7), and the main insulating layer 11 is formed. The casting resin can be applied as long as it is a compound having two or more epoxy groups in one molecule. A predetermined amount of an acid anhydride curing agent is mixed with bisphenol A type epoxy resin or bisphenol F type epoxy resin, and silica is added. An inorganic filler such as alumina is also added with a predetermined amount. It is desirable to adjust the addition amount of the inorganic filler so that the linear expansion coefficient is the same as that of the metal caps 4 and 7 made of copper. As the casting, a general vacuum casting with a mold temperature of 120 to 150 ° C. is used.

The partial discharge characteristics depending on the presence or absence of the insulating coatings 6 and 10 are shown in Table 1. However, in the case where the insulating coatings 6 and 10 were provided, there was no peeling between the metal caps 4 and 7 and the main insulating layer 11 and the characteristics were excellent. . In the case where the insulating coatings 6 and 10 were not provided, the partial discharge characteristics deteriorated. As test conditions, the insulation thickness of the main insulating layer 11 is 25 mm, and a ground layer is provided on the outer periphery.

  Thereby, the pre-cured insulating coatings 6 and 10 having a low thermal deformation temperature can alleviate the residual stress generated in the casting resin being cured, and can improve the adhesive force. The insulating coatings 6 and 10 and the main insulating layer 11 are the same kind of epoxy resin material. Further, the metal caps 4 and 7 side has an anchor effect due to roughening, and the main insulating layer 11 side can prevent stress concentration due to the smooth surfaces of the insulating coatings 6 and 10 and further has an adhesive strength. Can be improved. In addition, it is not preferable that the thermal deformation temperature of the insulating coatings 6 and 10 is high because cracks and the like occur in the coating itself.

  According to the resin cast product of Example 1, the main insulating layer 11 is formed by providing the metal caps 4 and 7 with the insulating coatings 6 and 10 having a thermal deformation temperature lower than that of the main insulating layer 11. Adhesive strength can be obtained, and excellent electrical characteristics can be obtained.

  Next, a resin cast product according to Embodiment 2 of the present invention will be described with reference to FIG. FIG. 4 is a cross-sectional view showing a configuration of a resin cast product according to Example 2 of the present invention. In addition, this Example 2 is different from Example 1 in that a bushing is used for a resin cast product. In FIG. 4, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 4, an insulating coating 23 having a thermal deformation temperature smaller than that of the main insulating layer 22 is provided around the center conductor 21 of the sandblasted aluminum. The center conductor 21 is aluminum, and has a larger linear expansion coefficient and a larger bonding area than the copper material of the first embodiment, but the basic main components of the main insulating layer 22 and the insulating coating 23 are the same as those of the first embodiment. is there. However, since the adhesion is improved by the insulating coating 23, excellent electrical characteristics can be obtained. The center conductor 21 is an electric member embedded in the main insulating layer 22.

  According to the resin cast product of the second embodiment, even if the material of the electric member embedded in the main insulating layer 22 is changed, the same effect as the first embodiment can be obtained.

  According to the embodiment as described above, it is possible to improve the adhesion between the insulating layer forming the main insulation and the electric member embedded in the insulating layer.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 1 Vacuum insulation container 2, 3 Sealing metal fittings 4, 7 Metal cap 5, 9 Current-carrying shaft 6, 10, 23 Insulation coating 8 Resin intrusion prevention pipes 11, 22 Main insulation layers 11a, 11b Interface connection part 21 Central conductor

Claims (6)

A main insulating layer cast with a casting resin;
An electrical member embedded in the main insulating layer and subjected to sandblasting;
A resin cast product, comprising: an insulating coating provided on a sandblasted surface of the electric member and provided with an insulating paint having a thermal deformation temperature lower than that of the main insulating layer.   2. The resin cast product according to claim 1, wherein the electrical member is a vacuum valve and a metal cap provided around a sealing fitting of the vacuum valve.   The resin cast product according to claim 1, wherein the electrical member is a central conductor constituting a bushing. The casting resin is obtained by adding a predetermined amount of an acid anhydride and an inorganic filler to a bisphenol A type epoxy resin,
4. The resin cast product according to claim 1, wherein the insulating paint is a mixture of an ester-based epoxy resin and a predetermined amount of dimer acid. 5. Apply sand blasting to electrical components,
Apply an insulating paint mixed with a predetermined amount of dimer acid to ester epoxy resin on its surface,
This is precured,
Set the pre-cured electrical member in the casting mold,
This casting mold is filled with a casting resin obtained by adding a predetermined amount of an acid anhydride and an inorganic filler to a bisphenol A type epoxy resin,
A method for producing a resin casting, characterized by being heat-cured.   The method for producing a resin cast product according to claim 5, wherein the surface subjected to the sandblast treatment with the insulating paint is smoothed.

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