JPH039206Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to improvement of high voltage insulating molded products.

Prior Art and Problems There is a high-voltage insulating molded product in which a cylindrical metal fitting is embedded in an epoxy resin molded body, and E in FIG. 3A shows a cable termination sleeve as an example thereof. In Fig. 3A, 1' is an epoxy resin molded body, 2' is a lower shield embedded in the molded body 1', 20' is an upper shield, 5' is a cable (51' is a cable insulator,
2' indicates a cable conductor), and 6' indicates a rubber cone.

In such an insulating molded product in which a metal fitting is embedded in an epoxy resin molded body, normal stress and stress are generated at the interface between the metal fitting and the epoxy resin body due to curing shrinkage of the epoxy resin, difference in coefficient of thermal expansion between the epoxy resin and the metal, etc. Shear stress is generated, and the tensile stress and shear stress of the normal stress act as an interfacial peeling force. To explain these stress states using the interface between the lower shield and the epoxy resin body in the cable termination sleeve as an example, as shown in Figure 3B, there is a shear stress τi and a tensile stress on the inner surface of the shield fitting. A stress δi acts on the outer surface, and a shear stress τo and a compressive stress δo act on the outer surface, so that the peeling force at the inner surface is considerably larger than that at the outer surface. For this reason, at this inner surface interface, peeling occurs that extends from the root of the shield fitting to the tip, and strong electrical stress acts on the tip due to the so-called electric field concentration effect, so the peeled surface of the tip Electric discharge may occur, eventually leading to penetrating failure.

On the other hand, if the adhesive force is made higher than the peeling force through adhesive treatment in order to prevent interfacial peeling, a large interfacial stress corresponding to the peeling force will be generated, leading to cracks in the epoxy resin molded body. , serious problems arise not only in electrical strength but also in mechanical strength and airtightness.

Purpose of the invention The purpose of the present invention is to provide a high-voltage insulating molded product that can eliminate interface peeling at the tip of a shield fitting or the above-mentioned interface crack by a simple means.

Structure of the invention The high-voltage molded product according to the present invention is a resin molded product in which a cylindrical metal fitting is embedded in a resin molded body, in which the tip of the cylindrical metal fitting protrudes inwardly in a curved shape, and includes the protruding surface. This structure is characterized in that adhesive treatment is applied to the tip of the metal fitting and the outer surface of the metal fitting.

Description of examples The present invention will be explained below with reference to the drawings.

In FIG. 1, 1 is an epoxy resin molded body. 2 is a cylindrical metal fitting, which is embedded in the resin mold body 1. At the tip of this cylindrical metal fitting 2, there is provided a protrusion 21 which can protrude in an arc shape toward the inner diameter side, and an adhesive treatment 3 is applied to the surface of this protrusion 21 and the outer surface of the metal fitting. The inner surface of the metal fitting is in an untreated state except for the above-mentioned protrusion surface, and for the above-mentioned adhesion treatment, an appropriate means capable of making the adhesive force stronger than that in the untreated state can be used. For example, it is possible to use sanding, coating with adhesive resin, or a combination of these, and additionally, grooves can be provided on the outer surface of the shield fitting as shown at 22 in FIG.

In FIG. 1, as in the case described above, a peeling force acts on the interface between the shield fitting 2 and the epoxy resin body 1 due to curing shrinkage of the epoxy resin, etc.
The peeling force on the inner surface of the shield fitting is considerably greater than on the outer surface, and the adhesive force on the inner surface excluding the tip protruding surface is smaller than the adhesive force on the outer surface.
The interface on the inner surface except for the protruding surface of the tip is easily peeled off, and no stress is generated at the interface, thereby preventing the occurrence of cracks. At the inner surface interface, when the resin body 1 tries to deform relative to the shield fitting 2, the deformation in the longitudinal direction is restrained by the protrusion 21 on the inner surface of the tip of the seal fitting. Because of this, the restraining stress can be alleviated, and since the adhesive force on the surface of the protrusion is increased by the adhesive treatment 3, peeling on the surface of the protrusion can be reliably eliminated. Therefore, it is possible to reliably prevent corona discharge from occurring at the tip of the shield fitting.

In the above, the tip of the shield fitting can be provided with a protrusion that protrudes not only toward the inner surface as described above but also in a curved shape on either the inner or outer surface (for example, the shield fitting shown in FIG. 20). In the case of a cable termination tube, as shown in FIG. 2, a lower shield fitting 2 and an upper shield fitting 20
The present invention can be applied to any of the following. In Fig. 2, 1 is an epoxy resin molded body, 2 is a lower shield metal fitting, 20 is an upper shield metal fitting,
21 and 21 indicate curved protrusions, and 3 and 3 indicate adhesive processing, respectively.

Effects of the invention The high-voltage insulating molded product according to the invention has the structure as described above, and by simply providing a curved protrusion at the tip of the cylindrical metal fitting and adhesively treating a part of the metal fitting, the high voltage insulating molded product according to the present invention This can prevent interfacial peeling or cracking of the insulator on the inner surface of the fitting. Therefore, these obstacles can be eliminated by simple means.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram showing one embodiment of the present invention;
The figures are explanatory diagrams showing another embodiment of the present invention, FIG. 3A is an explanatory diagram showing a conventional high-voltage insulating molded product, and FIG. 3B is an explanatory diagram showing the stress state of the conventional molded product. In the figure, 1 is a resin molded body, 2 is a cylindrical metal fitting, 21 is a curved protrusion, and 3 is an adhesive treatment part.

Claims (1)

[Scope of utility model registration request] In a resin molded product in which a cylindrical metal fitting is embedded in a resin mold body, the tip of the cylindrical metal fitting is made to protrude inwardly in a curved shape, and an adhesive treatment is applied to the metal fitting tip including the protruding surface and the outer surface of the metal fitting. A high voltage insulating molded product characterized by: