JPH0574911B2 - - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to a method of forming a cable connection, and more particularly to a method of forming a cable connection having a rubber-plastic insulation reinforcement.

[Technical Background of the Invention] Conventionally, the following method has been used as a method for forming a connection portion of a crosslinked rubber/plastic insulated cable.

That is, a rubber/plastic insulating reinforcing material that can be crosslinked by heating is formed on the outer periphery of the cable conductor connection section, which has been stripped in stages and conductor connections are made, by tape wrapping molding or injection molding, and then as shown in FIG. a preformed heat-crosslinkable rubber/plastic insulation reinforcement 1;
A heat-resistant presser tape 2 such as polyimide tape is wound around the outer circumference of the cable, and the end of the presser tape 2 is split into two stepped cylindrical pieces on the outer semiconductive layer 4 of the cross-linked rubber/plastic insulated cable 3. Presser metal fitting 5
, and then press the presser tape 2 from this presser metal fitting 5.
Silicone rubber heat shrink tube 6
Press and fix. Next, a two-part cylindrical airtight container 8 is fitted onto the presser metal fitting 5 through the packing 7, and the packing 7 is tightened with the tightening metal fitting 9 to fix the airtight container 8 airtightly.

Thereafter, pressure gas is sealed in the airtight container 8, and the rubber/plastic insulation reinforcement 1 is heated by a heating means placed in the airtight container 8 to crosslink it.

The thus crosslinked rubber/plastic insulation reinforcement 1 is coated with a semiconductive heat shrinkable tube (not shown) based on rubber/plastic, and heated again to fuse them together. The connection part is completed.

[Problems with the Background Art] However, such conventional methods require two heating steps: crosslinking the rubber/plastic insulation reinforcement 1 and fusing the semiconductive heat-shrinkable tube, and also cause the cable to deteriorate. When the holding tape 2 expands once in the heating process and contracts in the next cooling process, the thermal deformation caused by the expansion of the cable during heating remains as a permanent deformation, so the airtight container 8 and the crosslinked rubber
The disadvantage is that gaps are created between the plastic insulated cables 3, through which pressure gas leaks, resulting in incomplete pressurization and deterioration of the properties of the cable connection.

[Object of the Invention] The present invention has been made to solve these difficulties, and is capable of crosslinking a rubber/plastic insulation reinforcement and fusing a semiconductive heat-shrinkable tube in one step. Moreover, it is an object of the present invention to provide a method for forming a cable connection part that does not cause leakage of pressure gas even during the cooling process after crosslinking.

[Summary of the Invention] That is, the method for forming a cable connection part of the present invention involves applying a crosslinked rubber/plastic-based half-layer to the outer periphery of a heat-crosslinkable rubber/plastic insulation reinforcement formed on a conductor connection part of a cable. Covering a conductive heat-shrinkable tube, an airtight container having a tube-gripping mechanism at both ends is fitted onto the outer periphery of the tube with the tube-gripping mechanism airtightly gripping the cylindrical end of the semi-conductive heat-shrinkable tube; After that, a pressure gas is sealed in the airtight container, and
The method is characterized in that the semiconductive heat-shrinkable tube and the rubber/plastic insulation reinforcement are heated to fuse them together.

[Embodiment of the Invention] The details of the present invention will be described below with reference to an embodiment shown in the drawings.

FIG. 1 is a partial sectional view for explaining one embodiment of the method of the present invention. In FIG. 1, parts common to those in FIG. 2 are given the same reference numerals.

In the present invention, first, a crosslinkable rubber/plastic insulated cable 3 is placed on the conductor connection portion of the crosslinked rubber/plastic insulated cable 3, which has been peeled off and connected, by a method such as tape wrapping molding or injection molding.
A plastic insulation reinforcement is formed.

Next, a stepped two-part cylindrical holding fitting 5 is attached to the outer semiconductive layer 4 of the rubber/plastic insulated cable 3 to be connected, and a semiconductive heat-shrinkable tube is attached so as to straddle these holding fittings 5. 10 is fitted and heat-shrinked. The inner diameter of the cylindrical holding fitting 5 is made slightly larger than the outer diameter of the outer semiconductive layer 4 in order to prevent deformation of the cable core during heat molding.

After that, a heat-resistant presser tape 2 such as polyimide tape is wound around the outer side of the presser metal fitting 5 except for the area on which the presser metal fitting 5 is placed, and an airtight container 8 is fitted onto the presser metal fitting 5 via the packing 7, and the packing is 7 is tightened from the outside with a tightening fitting 9, and the airtight container 8 is fixed airtightly.

Thereafter, while supplying pressure gas into the airtight container 8, the rubber/plastic insulation reinforcement 1 is heated by an infrared heater (not shown) or any other heating means previously placed inside the container 8, and is crosslinked. At the same time, the semiconductive heat-shrinkable tube 10 and the rubber/plastic insulation reinforcement 1 are fused together.

In this heating process, the rubber/plastic insulation reinforcement and the insulation layer of the crosslinked rubber/plastic insulated cable thermally expand, and then contract again in the cooling process, but through this heating and cooling process, the airtight container 8 becomes semiconductive. Since it is airtightly crimped through the heat shrink tube 10 and the packing 7,
Pressure gas does not leak from inside the airtight container 8, and therefore a void-free connection with good characteristics can be obtained.

After that, the fastening fittings 9 are removed, the airtight container 8 is opened, the holding tape 2 is removed, the unnecessary portion of the semiconductive heat-shrinkable tube 10 is cut off, the end portion is shaped, and then a protective coating is applied using a conventional method. By applying this, the cable connection part is completed.

[Effects of the Invention] As explained above, according to the present invention, the formation of the rubber/plastic insulating reinforcement and the formation of the outer semiconductive layer can be performed in the same process, and the pressure gas is removed through the heating and cooling processes. Since leakage can be prevented, a void-free cable connection with good characteristics can be formed. Further, a cylindrical holding fitting having a diameter slightly larger than the outer diameter of the outer semiconducting layer is attached to the outer periphery of the outer semiconductive layer, and a semiconductive heat-shrinkable tube is covered by spanning between the holding fittings. Therefore, the expansion of the cable core of the heating mold can be absorbed between the cable core and the holding fitting, and it is possible to provide a cable connection portion without the risk of deformation of the cable core.

[Brief explanation of drawings]

FIG. 1 is a partial longitudinal sectional view for explaining an embodiment of the method for forming a cable connection portion of the present invention, and FIG. 2 is a partial longitudinal sectional view for explaining a conventional method for forming a cable connection portion. . DESCRIPTION OF SYMBOLS 1... Rubber/plastic insulation reinforcement body crosslinkable by heating, 2... Holding tape, 3... Crosslinked rubber/plastic insulated cable, 4... External semiconductive layer, 5... Holding metal fitting, 6... Silicone rubber 7... Packing, 8... Airtight container, 9... Fastening fittings, 10... Semiconductive heat shrinkable tube.

Claims (1)

[Claims] 1 The outer periphery of the heat-crosslinkable rubber/plastic insulation reinforcement formed on the conductor connection part of the cable has an inner diameter slightly larger than the outer diameter of the cable core, and is fitted in advance to the outer periphery of the cable core. A semiconductive heat-shrinkable tube based on cross-linked rubber/plastic is covered between the cylindrical fittings,
An airtight container having a tube gripping mechanism at both ends is fitted onto the outer periphery of the semiconductive heat-shrinkable tube while the tube gripping mechanism airtightly grips the cylindrical end of the semiconductive heat-shrinkable tube. 1. A method of forming a cable connection portion, comprising: enclosing the semiconductive heat-shrinkable tube and the rubber/plastic insulating reinforcing body to fuse them together.