JPS6318132Y2 - - Google Patents

Description

[Detailed explanation of the invention] This invention is a cross-linked polyethylene insulated cable (hereinafter referred to as
This relates to improvements to the connection part of CV cables.

Conventionally, as one of the connections of CV cables, the end of the cable insulation layer was sharpened with a pencil to expose the conductor, a connection fitting was attached to the conductor, and silane cross-linking was performed by injection molding across the connection fitting and the cable insulation layer. Some have a polyethylene insulation reinforcing layer formed thereon.

However, when forming the insulation reinforcing layer by injection molding silane-grafted polyethylene, the connection part of the above structure has a diameter of about 0.1 to 0.5 mm on the surface of the cable insulation layer at the contact interface between the insulation reinforcement layer and the cable insulation layer. There was a problem with cracks forming. The reason for this is thought to be that the contraction force when the injection-molded silane-grafted polyethylene crosslinks also acts on the surface of the cable insulation layer.

Therefore, it may be possible to prevent cracks on the cable surface to some extent by increasing the surface temperature of the cable insulation layer and injection molding silane-grafted polyethylene to better fuse the silane-crosslinked polyethylene to the surface of the cable insulation layer. Thinking that this might be the case, I injection-molded the silane-grafted polyethylene at high temperatures, but when I injection-molded the silane-grafted polyethylene at high temperatures, the cable insulation layer softened due to the heat and became thinner due to the pressure during molding. This causes a problem in that the silane grafted polyethylene flows out from the end of the mold.

This idea was created in view of the above problems.
The present invention provides a connecting portion of a crosslinked polyethylene insulated cable that does not cause cracks on the surface of the cable insulating layer at the contact interface between the insulating reinforcing layer and the cable insulating layer.

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

Reference numeral 1 is a CV cable, in which the tip of the cable insulation layer 2 is pencil-sharpened to expose the conductor 3. A connecting fitting 4 is attached to the conductor 3. A crosslinked polyethylene insulation reinforcing layer 5 is provided on the connection fitting 4 and the cable insulating layer 2 by injection molding silane grafted polyethylene and crosslinking with silane. This structure is the same as the conventional one, but in the present invention, the insulation reinforcing layer 5 and the cable insulation layer 2
A polyethylene film adhesive layer 6 is placed on the contact interface with the
is interposed. This fusion layer is made by wrapping one or two layers of polyethylene film around the outer circumference of the cable insulation layer.
It is formed by fusing these together. Note that the fusion layer is provided to a length that slightly protrudes from the end of the insulation reinforcing layer.

To form the connection part of the above structure, the cable insulating layer 2 is sharpened to expose the conductor 3, and before or after attaching the connecting fitting 4 to the conductor 3,
A fusion layer 6 of polyethylene film is formed on the outer peripheral surface of the end portion of the cable insulation layer, and then an insulation reinforcing layer 5 is molded.

In the above embodiment, a terminal fitting is used as the connecting fitting, but instead of this, a well-known intermediate connecting fitting having conductor insertion holes at both ends may be used. In this case, a fusion layer of polyethylene film is provided on the CV cable insulation layer on both sides of the intermediate connection fitting.

As described above, the CV cable connection part according to the present invention has a fusion layer of polyethylene film interposed at the contact interface between the insulation reinforcing layer made of injection molded silane-grafted polyethylene and the cable insulation layer.
The insulation reinforcing layer is well fused to the polyethylene film fusion layer, resulting in a good fusion bond, and the shrinkage force of the insulation reinforcement layer is no longer applied to the cable insulation layer, which prevents cracks from forming on the outer surface of the cable insulation layer. can also be definitely prevented.

[Brief explanation of drawings]

The drawing is a half sectional view showing an embodiment of a connecting portion of a cross-linked polyethylene insulated cable according to the present invention. 1 is a cross-linked polyethylene insulated cable, 2 is an insulating layer, 3 is a conductor, 4 is a connecting fitting, 5 is an insulation reinforcing layer,
6 is a fusion layer.

Claims (1)

[Scope of utility model registration request] Cross-linked polyethylene made by sharpening the end of the cable insulation layer to expose the conductor, attaching a connecting fitting to the conductor, and providing a silane cross-linked polyethylene insulation reinforcing layer by injection molding over the connecting fitting and the cable insulation layer. A connecting portion of a cross-linked polyethylene insulated cable, characterized in that a fusion layer of polyethylene film is interposed at the contact interface between the insulation reinforcing layer and the cable insulating layer in the connecting portion of the insulated cable.