JPH0568075B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method of forming an insulator connection portion by a tape winding molding method.

[Technical background of the invention and its problems] Conventionally, as a method for forming a connection part of a crosslinked polyethylene insulated cable, etc., a crosslinkable semi-conductor is used in which a crosslinking agent is added to the outer periphery of a conductor connection part in which the conductor is sleeve-connected by stripping the conductor. A conductive rubber/plastic tape is wound around it and heated using a mold or the like to fuse the semiconductive rubber/plastic tape together and crosslink at the same time to form an internal semiconductive layer. A method is used in which a crosslinkable insulating rubber/plastic tape containing a crosslinking agent is wound and then heated again using a mold or the like to fuse and crosslink the tape to form an insulating reinforcing layer.

However, in this method, the tape is fused and crosslinked in two steps, so it takes a long time to form the connection, and the workability is extremely low. Furthermore, the edges of the tape cause protrusions on the surface of the formed semiconductive layer. The problem was that it was formed.

Recently, in order to deal with this problem, a method of using a semiconductive heat shrink tube instead of the semiconductive rubber/plastic tape described above (Japanese Patent Application Laid-Open No. 57-11991) has been proposed.
126085) has been proposed.

This method shortens the working time and provides a smooth surface for the internal semiconducting layer, but this method causes further heat shrinkage during heating molding of the insulating rubber/plastic tape, resulting in poor adhesion to the insulating layer. However, there were disadvantages in that the cable conductor and connection sleeve's shape became uneven, and the shape of the cable conductor and connection sleeve appeared as steps on the surface, reducing the intended effect.

[Object of the Invention] The present invention has been made in response to such conventional circumstances, and provides a cable in which a cable connection portion with a smooth internal semiconducting layer and excellent electrical properties can be easily formed in a short time. The present invention attempts to provide a method for forming a connection part.

[Summary of the Invention] That is, the method for forming a cable connection portion of the present invention includes forming an internal semiconductive layer and an insulating reinforcing layer on the outer periphery of a conductor connection portion of a rubber/plastic insulated cable in which the conductor is sleeve-connected by stripping the conductors.
A cross-linkable semiconductive rubber/plastic tape is wound in an almost spindle shape from the top of the connection sleeve to the internal semiconductive layer of the cable, and then a heat-resistant tape is wound on top of the tape, which is then heated from the outside to form the semiconductive layer. Only the outermost layer of the semiconductive rubber/plastic tape and its vicinity are fused and semi-crosslinked, and then the heat resistant tape is removed to form a crosslinkable layer on the semiconductive rubber/plastic tape wound layer and the insulating layer of the cable. The insulating rubber/plastic tape is wound into a spindle shape, and then the insulating rubber/plastic tape wound layer and the semiconductive rubber/plastic tape wound layer are fused and integrated by heating to completely crosslink. It is a feature.

[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 longitudinal sectional view of a cross-linked polyethylene insulated cable connection section for explaining the method of the present invention;
The figure is an enlarged sectional view of a part of the semiconductive crosslinked polyethylene tape wound layer.

In this embodiment, first, the cable conductors 1, 1 of the crosslinked polyethylene insulated cables 4, 4, which are stripped in stages to expose the cable conductor 1, the cable internal semiconducting layer 2, and the cable insulator 3, are removed using the connecting sleeve 5. Connected.

Next, a wound layer 6 is formed of a crosslinkable semiconductive polyethylene tape containing a crosslinking agent between the inner semiconductive layers 2 of the cable.

In the present invention, at that time, a crosslinkable semiconductive polyethylene tape containing a crosslinking agent is wound in a substantially spindle shape to fill the step between the connection sleeve 5 and the internal semiconductive layer 2. .

Next, this semiconductive polyethylene tape winding layer 6
A heat-resistant tape 7, such as a polyimide tape, is pressed and wound on top, and the surface of the semiconductive polyethylene tape wound layer 6 is heated from the outside using a dryer or the like. This heating only needs to fuse the outermost layer of the semiconductive polyethylene tape wound layer 6 or its vicinity to obtain at least a semi-crosslinked state, that is, a degree of crosslinking of about 60%. For example, if a 1000W dryer is used, 4 ~5 minutes of heating is sufficient.
In FIG. 2, M indicates a fused half-bridge.

In this heat treatment, only the surface layer of the semiconductive polyethylene tape wound layer 6 is heated to the temperature necessary for fusion crosslinking, so almost no thermal stress acts from inside, and the surface layer 6 is smooth and smooth. This method has the advantage that a smooth surface can be obtained and the work can be completed in a short time.

Moreover, since this heat treatment is carried out in a short time, the temperature returns to room temperature quickly, and the heat-resistant tape 7 can be removed and the formation of the insulating reinforcing layer 8 can be started after only a short time of cooling. be.

Thereafter, a cross-linkable insulating polyethylene tape containing a cross-linking agent is wound over the inner semi-conductive layer 6 across the cable insulators 3, 3, and heat-molded using a conventional method to form an insulation reinforcing layer 8. Ru.

In this heat molding process, the internal semiconducting layer 6
Although thermal stress is also generated from the side, the layer thickness of the insulating polyethylene tape wound layer is sufficiently larger than that of the internal semiconductive layer, and the surface portion of the internal semiconductive layer 6 is semi-crosslinked or crosslinked. A connection portion of a crosslinked polyethylene insulated cable having good electrical properties is formed without impairing the smoothness of the surface of the internal semiconducting layer.

In the above embodiments, an example in which the present invention is applied to the formation of a connection part of a cross-linked polyethylene cable has been described, but the present invention should not be limited to such an embodiment, and can be applied to the connection of other rubber/plastic cables. It is similarly applicable to the formation of parts.

[Effects of the Invention] As explained above, according to the present invention, crosslinkable semiconductive rubber/plastic tape is wound approximately in a spindle shape from the conductor connection sleeve to the internal semiconductive layer of the cable, and the outer surface of Since the internal semiconducting layer was formed by fusing the two layers by heating for a short period of time to obtain half-crosslinking, a cable connection portion having excellent electrical properties can be formed in a short period of time.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of a cross-linked polyethylene insulated cable connection section for explaining the method of the present invention, and FIG. 2 is an enlarged longitudinal cross-sectional view of a portion of the semiconductive polyethylene tape wound layer. DESCRIPTION OF SYMBOLS 1... Cable conductor, 2... Cable internal semiconducting layer, 3... Cable insulation layer, 4... Crosslinked polyethylene insulated cable, 5... Connection sleeve, 6...
... Semi-conductive polyethylene tape winding layer, 7 ... Heat-resistant tape, 8 ... Insulating reinforcing layer, M ... Fusion half-crosslinked part.

Claims (1)

[Claims] 1. When forming an internal semiconducting layer and an insulating reinforcing layer around the outer periphery of the conductor connection part of a rubber/plastic insulated cable whose conductors are sleeve-connected after being stripped in one step,
A cross-linkable semiconductive rubber/plastic tape is wound in an almost spindle shape from the top of the connection sleeve to the internal semiconductive layer of the cable, and then a heat-resistant tape is wound on top of the tape, which is then heated from the outside to form the semiconductive layer. Only the outermost layer of the semiconductive rubber/plastic tape and its vicinity are fused and semi-crosslinked, and then the heat resistant tape is removed to form a crosslinkable layer on the semiconductive rubber/plastic tape winding layer and the insulating layer of the cable. The insulating rubber/plastic tape is wound into a spindle shape, and then the insulating rubber/plastic tape wound layer and the semiconductive rubber/plastic tape wound layer are fused and integrated by heating to completely crosslink. Characteristic method for forming cable connections.