JPH03107319A - Formation of edge-cut splice of cable - Google Patents

Abstract

PURPOSE:To improve the workability and enable precise rounding by rounding an end of a semiconductor heat-shrinkable tube after temporary shrink for thickening the wall thereof. CONSTITUTION:A semiconductor heat-shrinkable tube 8 not shrunk is fitted to a cylinder 9 to regulate the diameter thereof after shrink so that the tube can be fitted to the taper of a mold insulator 3 and is temporarily contracted to the outside diameter of the cylinder 9 with a heater, etc., to thicken the tube wall, the cylinder 9 is pulled out, and the end face of a tip A is rounded semi-circularly. The periphery, on which an edge-cut insulating layer is to be formed, of the semiconductor heat contraction tube used as an internal semiconductor layer is cut with sawteeth or glass and roughened.

Description

[Detailed description of the invention] [Promise of invention] (Industrial application field) The present invention relates to a method of forming a cable edge connection.

(Prior Art) Conventionally, the edge-cut connection portion of a crosslinked polyethylene insulated cable (CV cable) has been formed by the following method.

That is, as shown in Fig. 2, first, the terminals of the cables to be connected are stripped in stages, and the exposed conductors 1a are connected in a conventional manner to form the conductor connection part 1, and the outer periphery of the conductor connection part 1 is coated with cable insulation. Mold insulator 3 on the spindle across the body 2
form. Next, a semiconductive heat shrinkable tube that has been previously rounded so that one end surface has a semicircular shape is placed from one cable external semiconductive layer 4 to the tapered part of the molded insulator 3, and the rounded end is molded. The inner semiconducting layer is formed by fitting the insulator so that it is located in the tapered part and heat-shrinking it.

Then, the surface of this heat-shrinked semiconducting heat-shrinkable tube is
In order to improve adhesion to the edge-cut insulating layer provided on the outer periphery, the surface is roughened by cutting with a saw blade or glass.

Next, an edge-cutting insulating layer 6 is formed on the outer periphery of the inner semiconductive layer 5,
A semi-conductive shrink tube with one end rounded in advance is inserted from the tapered part of the edge-cut insulating layer 6 to the other cable semi-conductive layer so that the rounded tip is positioned on the edge-cut insulating layer 6, and heated. Shrink it.

(Problem to be Solved by the Invention) When forming the edge-cut connection part of the cable by such a method, a higher electric field is concentrated on the inner semiconducting layer 5 than on the outer semiconducting layer 7. High precision is required for rounding the tip of the semiconductive heat-shrinkable tube used for the conductive layer.

On the other hand, since the thickness of the semiconducting heat-shrinkable tube used for the inner semiconducting layer needs to be thin, it is difficult to round it and process it with high precision.

The present invention has been made in response to such conventional viewpoints, and provides an edge-cut connection that improves the insulation performance of the edge-cut insulation part by making it possible to accurately round the end of a semiconductive heat-shrinkable tube. The purpose of the present invention is to provide a method for forming a part.

[Structure of the Invention] (Means for Solving the Problems) The present invention forms a spindle-shaped molded insulator on the outer periphery of a conductor connection portion of a cable, and the molded insulator is formed from an external semiconductive layer of one cable. A first semiconductive heat-shrinkable tube is fitted over the tapered part and heat-shrinked to form an inner semiconductive layer, and then an edge-cut insulating layer is formed around the outer periphery of the inner semi-conductive layer, and from this edge-cut insulating layer the other In a method of forming a cable edge connection by fitting and heat-shrinking a second semi-conductive heat-shrinkable tube over an outer semi-conductive layer of a cable, at least one end of the first semi-conductive heat-shrinkable tube is After temporarily shrinking to increase the wall thickness, this end is rounded, and the one end of the semiconductive heat shrinkable tube is placed in the tapered part of the molded insulator. It is characterized in that the cable is fitted from the outer semiconductive layer to the tapered part of the molded insulator and is thermally shrunk.

Note that before the first semiconducting heat shrinkable tube used for the inner semiconducting layer is fitted from the outer semiconducting layer of one cable to the tapered part of the mold insulator, the surface is roughened in advance. By doing so, it is possible to improve the adhesion with the edge-cut insulating layer formed on the inner semiconductive layer. The edge of the second semiconductive heat shrink tube also has a first
Although it is preferable to round the tube in the same manner as the semiconductive heat shrink tube, it is also possible to use a tube processed by conventional methods.

(Function) Since the heat-shrinkable tube is formed to shrink mainly in its circumferential direction, its wall thickness increases when it shrinks. That is, as shown in the longitudinal section of FIG.
When it is heat-shrinked to a diameter d2 as shown in Figure (b), the wall thickness becomes thicker by α.

In the present invention, by using this method, the thickness of the semiconductive heat-shrinkable tube is increased, the workability of the rounding process is improved, and the rounding process is performed with high accuracy. Also, prior to forming the connection part,
By roughening the surface of the semiconducting heat shrink tube used for the inner semiconducting layer in advance, the adhesion with the edge-cut insulating layer provided around the outer periphery of the inner semiconducting layer is improved, and the semiconducting tube generated during processing is also improved. If conductive cutting debris is removed by cleaning in advance, cutting debris will not be mixed into the edge-cutting insulating layer and the insulation performance will not deteriorate.

(Example) Next, one embodiment of the present invention will be described using the drawings.

In this embodiment, as shown in FIG. 1(a), the shrinkage diameter of the unshrinkable semiconductive heat shrinkable tube 8 is limited to a size that allows it to fit into the tapered part of the mold insulator 3. It is fitted into the cylindrical body or cylindrical body 9 for
As shown in b), the cylindrical body 9 is temporarily contracted to its outer diameter using hot air, a heater, etc. to increase its wall thickness, and then the cylindrical body 9 is pulled out to form the tip end as shown in FIG. 1(C). Round the end face of A into a semicircle. Thereafter, the semiconductive heat-shrinkable tube used as the inner semiconductive layer is roughened by cutting the outer periphery on which the edge-cut insulating layer is to be formed with a saw blade, glass, or the like.

Next, insert semiconductive heat shrink tubes with rounded ends into both of the stripped rubber/plastic cables to be connected, such as Cv cables, so that the rounded ends are on the connection side. , as shown in Figure 2,
The conductors are connected in a conventional manner to form the conductor connection part 1, and then the inserted conductive heat shrink tube is shifted onto the cable sheath to form each cable insulator 2 around the outer periphery of the conductor connection part 1.
A spindle-shaped molded insulator 3 is formed across the two.

Next, from the outer semiconductive layer 4a of one cable to the tapered part of the molded insulator 3, the outer peripheral part is roughened, and the first semiconductive heat shrink tube inserted earlier is
The rounded end portion is fitted onto the tapered portion of the molded insulator 3, and the inner semiconductive layer 5 is formed by heat shrinking using hot air, a heater, or the like.

Further, an insulating rubber tape is wound around the outer periphery of this inner semiconductive layer 5 to form an edge-cutting insulating layer 6, and finally, from the edge-cutting insulating layer 6 to the other cable semiconductive layer 4b, the tape is similarly shifted onto the cable sheath and covered. The second semiconductive heat-shrinkable tube that has been fitted is fitted and heat-shrinked to form the outer semiconductive layer 7.
form.

At this time, one end of the semiconductive heat-shrinkable tube that has been rounded is placed on the edge-cut insulating layer 6.

In the edge cutting connection part of the cable formed in this way, the workability is good when rounding the edge of the semiconducting heat shrinkable tube used for the semiconducting layer, and since the edge is pre-shrinked in advance, it is easy to work when forming the connection part. The shrinkage work is also included in the product.

Furthermore, since the surface of the inner semiconducting layer is roughened, the adhesion between the inner semiconducting layer and the edge-cutting insulating layer is good, and if the surface is roughened in a separate process from the formation of the connection part, cutting debris etc. Since the environment during connection formation is not polluted, no foreign matter was found in the formed connections and the insulation performance was good.

[Effects of the Invention] As explained above, according to the method of the present invention, the edge of the semiconductive heat-shrinkable tube is pre-shrinked to increase its wall thickness and then rounded, which improves workability. Precise rounding can be performed, and if the surface of the semiconductive heat shrink tube used for the inner semiconductive layer is roughened and cleaned, it will have better contact with the edge-cut insulating layer, making it easier to cut during roughening. Since there is no contamination of debris, the insulation performance is also improved.

[Brief explanation of drawings]

FIGS. 1(a) to C) are longitudinal cross-sectional views illustrating the process of rolling a semiconductive heat-shrinkable tube in the method of the present invention;
FIG. 2 is a longitudinal cross-sectional view of a cable edge-cut connection section for explaining the method of the present invention.

Claims (1)

[Claims] (1) A spindle-shaped molded insulator is formed around the outer periphery of the conductor connection portion of the cable, and a first semiconductive heat-shrinkable tube is fitted from the outer semiconductive layer of one cable to the tapered portion of the molded insulator. heat shrinking to form an inner semiconducting layer, then forming an edge-cut insulating layer around the outer periphery of the inner semi-conducting layer, and a second semi-conducting heat-shrinkable tube extending from the edge-cutting insulating layer to the outer semiconducting layer of the other cable. In the method of forming a cable edge connection by fitting and heat-shrinking the first semi-conductive heat-shrinkable tube, at least one end of the first semi-conductive heat-shrinkable tube is temporarily shrunk to increase the wall thickness, and then this end is a tapered portion of the molded insulator from the outer semiconductive layer of the one cable, such that the rounded end of the semiconducting heat shrink tube is located in the tapered portion of the molded insulator; A method for forming an edge-cut connection part of a cable, which comprises heat-shrinking the cable by fitting it over the cable.