JPH0638355B2 - CV cable mold connection method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a CV cable mold connecting method, and more particularly to a mold connecting method using an edge cutting unit.

[Prior Art] As shown in FIG. 1, a CV cable, that is, a cross-linked polyethylene insulated vinyl sheath cable is connected by connecting the cable conductors 1a and 1b of the CV cables 1A and 1B with each other after a pencil ring, and surrounding the connecting portion. The sleeve 2 is covered with the sleeve 2, and the outer periphery of the sleeve 2 is extruded to form an insulator 3 for joints made of an uncrosslinked insulator by tape winding, and an edge cutting unit 4 premolded thereon is shown by an arrow a in FIG. Then, as shown in FIG. 2, the outer conductive layer 5 is provided on the outer peripheral surface of the insulator 3 for the joint and the outer peripheral surface of the edging unit 4 inserted in a part of the outer peripheral surface. The entire CV cable 1 is integrally molded.

[Problems to be Solved by the Invention] In such a conventional CV cable mold connection method, when the edging unit 4 is fitted into the insulator 3 for the joint, the rim cutting unit 4 and the inner peripheral surface of the edging unit 4 are A small gap 6 is always formed between the joint insulator 3 and the outer peripheral surface of the insulator 3.

As shown in FIG. 2, an outer conductive layer 5, which is generally a heat-shrinkable tube, is attached to the outer peripheral surface of the joint insulator 3 and the outer peripheral surface of the edging unit 4 fitted to a part of the outer peripheral surface. If the temperature is raised to mold the entire CV cable 1 integrally provided, the insulator 3 for joints, which is an uncrosslinked insulator, melts and the gap 6 disappears.

However, when the gap 6 is large, or when the outer conductive layer 5
When there is no great difference in melting point between the joint insulator 3 and the joint insulator 3, as shown in FIG. 3, the outer conductive layer 5 prevents the gap 6 formed between the edging unit 4 and the joint insulator 3 from forming. There is a possibility that it may enter the concave portion and form the convex portion 5a.

When such a convex portion 5a is generated, the withstand voltage performance of the joint portion is deteriorated.

Therefore, an object of the present invention is to provide a mold connecting method for a CV cable which eliminates the above-mentioned conventional drawbacks.

[Means and Actions for Solving Problems] In the present invention, the same material is used as the material for forming each of the joint insulator, the edging unit, and the external conductive layer, and the edging unit is insulated for the joint. Before the insertion into the body, the edging unit was heated to a high temperature and then inserted into the insulator for the joint.

[Embodiment] The mold connection method for a CV cable according to the present invention will be described below with reference to an embodiment shown in the drawings.

As shown in FIG. 1, the cable conductors 1a and 1b of the CV cables 1A and 1B are connected with each other after pencilling, a sleeve 2 is covered around the connecting portion, and the outer circumference thereof is extruded or tape-unwrapped. The joint insulator 3 in the state described above is covered, and the edging unit 4 which has been heated to a high temperature is fitted on the joint insulator 3 at room temperature as indicated by an arrow a in FIG.

Next, as shown in FIG. 2, a part of the outer peripheral surfaces of the CV cables 1A and 1B and the outer peripheral surface of the insulator 3 for joint,
A part of the outer peripheral surface of the edge cutting unit 4 is covered with the external conductive layer 5.

At this time, the heat of the heated edging unit 4 is conducted toward the joint insulator 3, and the edging unit 4 is attached to the boundary surface between the edging unit 4 and the joint insulator 3.
Contracts so that considerable pressure is applied inwardly towards the joint insulator 3.

Further, in this state, the joint insulator 3 is in a non-crosslinked state, and the edging unit 4 and the outer conductive layer 5 are in a crosslinked state. However, the pressure of the boundary surface causes the temperature rise process for heating the entire connection portion. Held up.

After this, the insulator 3 for the joint and the edge cutting unit 4
In order to bring the external conductive layer 5 into a crosslinked state, the entire connecting portion is heated and the temperature is gradually raised.

Then, in the vicinity of the melting points of the joint insulator 3, the edging unit 4, and the outer conductive layer 5, the joint insulator 3 is softened, and the joint insulator 3 flows due to the pressure of the boundary surface. Without forming the convex portion 5a shown in FIG. 3, as shown in FIG. 4, due to the flow effect of the insulator 3 for the joint due to the pressure of the boundary surface, the edging unit 4 and the outer conductive layer 5 are separated from each other. In the meantime, the outer conductive protrusion 3a of the joint insulator 3 is formed, and the protrusion 3a is formed in contrast to the convex portion 5a of the outer conductive layer 5 as shown in FIG. Therefore, the withstand voltage performance of the connecting portions of the cable conductors 1a and 1b of the CV cables 1A and 1B is not reduced.

This is because the same material is used as the material forming each of the joint insulator 3 and the outer conductive layer 5 of the edging unit 4, and the respective materials are selected so that there is no great difference in the melting points of the respective materials. This is because the joint insulator 3 is in an uncrosslinked state, and this flows between the edging unit 4 and the outer conductive layer 5 to generate the protrusion 3a of the joint insulator 3.

The heating of the edge cutting unit 4 needs to be below the melting point of the material of the edge cutting unit. When this material is cross-linked polyethylene, a temperature of around 100 ° C is desirable.

[Effects of the Invention] As described above, according to the present invention, the edging unit is heated and fitted into the insulator for the joint, and the insulator for the joint, the edging unit, and the outer conductive layer are close to the melting point. Since each of them is integrated in a crosslinked state, it is possible to prevent an outer conductive protrusion from being formed in the insulator for the joint, so that it is possible to prevent the withstand voltage performance of the connecting portion from being lowered and to stabilize the connecting portion. .

[Brief description of drawings]

1 and 2 are cross-sectional views showing the principal part of the CV cable mold connection method, FIG. 3 is an enlarged cross-sectional view of the main part of the connection part by the conventional CV cable mold connection method, and FIG. It is a principal part expanded sectional view of the connection part by the mold connection method for CV cables of this invention. 1a, 1b ... Cable conductor 3 ... Insulator for joint 4 ... Edge cutting unit

Claims (1)

[Claims] Claim: What is claimed is: 1. Connecting cable conductors, extruding on the outer periphery thereof, and winding a tape to form an insulator for joints, which is an uncrosslinked insulator, and on the outer periphery of the same material as the insulator for joints. In the mold connecting method for a CV cable, in which a preliminarily molded edge-cutting unit is inserted and molded integrally, in the state where the edge-cutting unit is heated, the edge-cutting unit is inserted in the insulator for the joint and further heated. It is characterized in that the edge cutting unit is contracted, and it is brought into close contact with the surface of the insulator for the joint under pressure, and then the whole of them is heated to perform the crosslinking treatment of the insulator for the joint. Mold connection method for CV cable.