JP2787346B2 - Method of forming cable edge connection - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial application field) The present invention relates to a method for forming an edge connection portion of a cable.

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

That is, as shown in FIG. 2, the terminal of the cable to be connected is first stripped off, and the exposed conductor 1a is connected by a conventional method to form a conductor connection portion 1. Mold insulator 3 on spindle over body 2
To form Next, a semiconductive heat-shrinkable tube which has been rounded so that one end surface is semicircular from one cable outer semiconductive layer 4 to the tapered portion of the mold insulator 3 is molded, and the rounded end is molded. The inner semiconductive layer is formed by being fitted and thermally contracted so as to be located at the tapered portion of the insulator.

Then, the surface of the heat-shrinkable semiconductive heat-shrinkable tube is cut with a saw blade or glass to roughen the surface in order to improve the adhesiveness to the edge insulating layer provided on the outer periphery.

Next, a trimming insulating layer 6 is formed on the outer periphery of the inner semiconductive layer 5, and a semiconductive shrink tube whose one end has been rounded in advance is rounded from the tapered portion of the trimming insulating layer 6 to the other cable semiconductive layer. It is fitted and heat-shrinked so that the formed front end is located on the border insulating layer 6.

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

On the other hand, it is necessary to reduce the thickness of the semiconductive heat-shrinkable tube used for the inner semiconductive layer, so that it is difficult to perform rounding and to perform processing with high accuracy.

The present invention has been made in view of such a conventional viewpoint, and enables a rounding process of an end portion of a semiconductive heat-shrinkable tube with high precision, thereby improving an insulating performance of a marginal insulating portion. It is an object of the present invention to provide a method for forming a part.

[Means for Solving the Problems] According to the present invention, a spindle-shaped mold insulator is formed on the outer periphery of a conductor connecting portion of a cable, and the mold insulator is formed from an external semiconductive layer of one cable. A first semiconductive heat-shrinkable tube is fitted over the tapered portion and heat-shrinked to form an inner semiconductive layer, and then a marginal insulating layer is formed on the outer periphery of the inner semiconductive layer. A method of fitting a second semiconductive heat-shrinkable tube over an outer semiconductive layer of a cable and heat shrinking to form an edge connection portion of the cable, wherein at least one end of the first semiconductive heat-shrinkable tube is formed. After temporarily shrinking to increase the wall thickness, the end is rounded, and the semiconductive heat-shrinkable tube is rounded so that the one end is positioned at the tapered portion of the mold insulator. Be fitted from outer semiconducting layer of the cable toward the tapered portion of the mold insulator is characterized by thermally shrinking.

Prior to fitting the first semiconductive heat-shrinkable tube used for the inner semiconductive layer from the outer semiconductive layer of one cable to the tapered portion of the mold insulator, the surface is roughened in advance. Thereby, the adhesiveness with the edge insulating layer formed on the inner semiconductive layer can be improved. Further, it is preferable that the edge of the second semiconductive heat-shrinkable tube is also rounded by the same method as that of the first semiconductive heat-shrinkable tube, but a material processed by a conventional method can also be used.

(Operation) Since the heat-shrinkable tube is formed so as to shrink mainly in the circumferential direction, the shrinkage increases in wall thickness. Or diameter d ₁ to indicate its longitudinal cross section 1 (a), the heat-shrinkable tube 8 of a thickness t _1, the thickness when the heat shrunk to a diameter d ₂ as the first diagram (b) is α Only thicker.

In the present invention, the thickness of the semiconductive heat-shrinkable tube is increased by this method, the workability of the rounding process is improved, and the rounding process is performed with high accuracy. In addition, prior to the formation of the connection portion, the surface of the semiconductive heat-shrinkable tube used for the inner semiconductive layer is roughened in advance, so that the adhesiveness with the edge insulating layer provided on the outer periphery of the inner semiconductive layer is improved. Further, if semi-conductive chips generated during processing are removed in advance by washing, there is no possibility that chips are mixed in the edge insulating layer and the insulation performance is not deteriorated.

Example Next, an example of the present invention will be described with reference to the drawings.

In this embodiment, as shown in FIG. 1 (a), the uncontracted semiconductive heat-shrinkable tube 8 restricts the contraction diameter to such an extent that it can be fitted on the tapered portion of the mold insulator 3. As shown in FIG. 1 (b), the cylindrical member 9 is temporarily shrunk to the outer diameter of the cylindrical member 9 using hot air, a heater, or the like to increase the wall thickness.
, And the end face of the distal end portion A is rounded into a semicircle as shown in FIG. 1 (c). Thereafter, the semiconductive heat-shrinkable tube used as the inner semiconductive layer is roughened by cutting the outer peripheral portion where the edge insulating layer is to be formed with a saw blade, glass or the like.

Then, after inserting the semiconductive heat-shrinkable tube with rounded ends into both the stepped-off rubber / plastic cable to be connected, for example, the CV cable, so that the rounded ends are on the connection side. , As shown in FIG.
The conductors are connected in a conventional manner to form a conductor connection portion 1, and then the inserted semiconductive heat-shrinkable tube is displaced over a cable sheath so that each cable insulator 2 is placed on the outer periphery of the conductor connection portion 1.
To form a spindle-shaped mold insulator 3.

Next, the outer peripheral portion is roughened from the outer semiconductive layer 4a of one cable to the tapered portion of the mold insulator 3, and the first semiconductive heat shrink tube inserted earlier is rounded. The inner semiconductive layer 5 is formed by fitting so that the portion is located at the tapered portion of the mold insulator 3 and thermally contracting using hot air or a heater.

Further, an insulating rubber tape is wound around the outer periphery of the inner semiconductive layer 5 to form a trim insulating layer 6, and finally, from the trim insulating layer 6 to the other cable semiconductive layer 4b, it is similarly displaced over the cable sheath and covered. The fitted second semiconductive heat-shrinkable tube is fitted and thermally shrunk to form the outer semiconductive layer 7.
To form At this time, the rounded end of the semiconductive heat-shrinkable tube is positioned on the edge insulating layer 6.

In the cut-off connection portion of the cable formed in this way, the workability when rounding the edge of the semiconductive heat-shrinkable tube used for the semiconductive layer is good. Contraction work becomes easy.

Furthermore, because the surface of the inner semiconductive layer is roughened,
Good adhesion between the inner semiconductive layer and the marginal insulating layer, and if the surface is roughened in a separate step from the formation of the connection, it will not pollute the environment at the time of formation of the connection with cutting debris. No foreign matter was found in the connection part, and the insulation performance was good.

[Effects of the Invention] As described above, according to the method of the present invention, the edge of the semiconductive heat-shrinkable tube is preliminarily shrunk in advance to increase the wall thickness and then to the rounding process. Precise rounding can be performed, and if the surface of the semiconductive heat-shrinkable tube used for the inner semiconductive layer is roughened and cleaned, the adhesion to the edge insulating layer is improved, and cutting chips during roughening are removed. Since there is no contamination, the insulation performance is further improved.

[Brief description of the drawings]

1 (a) to 1 (c) are longitudinal sectional views for explaining a step of rounding a semiconductive heat-shrinkable tube in the method of the present invention.
FIG. 2 is a longitudinal sectional view of an edge connection portion of a cable for explaining the method of the present invention. DESCRIPTION OF SYMBOLS 1 ... Conductor connection part 2 ... Cable insulator 3 ... Mold insulator 4a, 4b ... Cable outer semiconductive layer 5 ... Inner semiconductive layer 6 ... Edge insulating layer 7 ... Outer semiconductive layer 8 ... … Semiconducting heat shrink tubing 9 …… Cylinder

Continued on the front page (72) Inventor Kazuo Yamaguchi 2-1-1, Oda Sakae, Kawasaki-ku, Kawasaki-shi, Kanagawa Prefecture Inside Showa Electric Wire & Cable Co., Ltd. (72) Inventor Toyohiko Fuharu 2-1-1, Oda-Ei, Kawasaki-ku, Kawasaki-shi, Kanagawa Prefecture No. 1 Inside Showa Electric Wire & Cable Co., Ltd. (56) References JP-A-61-128712 (JP, A) JP-A-63-18915 (JP, A) JP-A-63-23508 (JP, A) 60-4648 (JP, B2) JP 2-61206 (JP, B2) (58) Fields investigated (Int. Cl. ⁶ , DB name) H02G 1/14 H02G 15/00-15/196

Claims (1)

(57) [Claims] 1. A spindle-shaped mold insulator is formed on an outer periphery of a conductor connecting portion of a cable, and a first semiconductive heat-shrinkable tube is covered from an outer semiconductive layer of one of the cables to a tapered portion of the mold insulator. Fitting and heat shrinking to form an inner semiconductive layer, then forming a marginal insulating layer on the outer periphery of the inner semiconductive layer, and extending a second semiconductive heat transfer layer from the marginal insulating layer to the outer semiconductive layer of the other cable. In the method of fitting a shrinkable tube and heat shrinking to form an edge connection portion of a cable, at least one end of the first semiconductive heat shrinkable tube is temporarily shrunk to increase the wall thickness. The semi-conductive heat-shrinkable tube is rounded, and the semi-conductive heat-shrinkable tube is cut off from the outer semi-conductive layer of the one cable so that the rounded end is located at the tapered portion of the mold insulator. The method of forming the edge cutting the cable connections, characterized in that over the tapered portion of the body to be fitted to thermal contraction.