JPH10326525A - Transfer cable - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To reduce the concentration of stress on strands of a shielding layer in a cable for movement and to suppress disconnection of the strands. SOLUTION: In a moving cable having a braided shielding layer, a copper stranded wire 4 is used for the shielding layer 3. That is, a cross-woven structure of the copper stranded wire 4 and the cotton yarn 5 having a plurality of copper wires as strands is used. By using the stranded wire 4 for the shielding layer 3, the application of stress due to external force to a specific element wire is reduced, and disconnection is suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a moving cable used in an uninterruptible bypass method for overhead distribution lines.

[0002]

2. Description of the Related Art A mobile cable is provided with a shielding layer on an outer semiconductive layer from the viewpoint of security and ensuring the performance of the cable. Usually, this shielding layer is 0.12mmφ ~ 0.20mmφ
It has a braided structure in which a small-diameter copper wire (metal wire) is woven, and the repeated bending, tension,
It is configured to withstand external forces such as twisting. For example, as shown in FIG. 4, a plurality of small-diameter copper wires 15 are arranged (or bundled) in parallel to form a unit strand 16 and a cotton thread 17, and the aggregate 16 is arranged in one direction. In many cases, a cross-woven braid in which the cotton yarn 17 is woven in a direction intersecting this is adopted.

[0003]

However, the moving cable having the conventional structure has the following problems. In a shielding layer braided by arranging a plurality of thin copper wires in parallel as one unit, a stress due to an external force during use of the cable is directly applied to each metal wire of the shielding layer. If the metal strands of the shielding layer are completely uniformly braided, there is no problem because the stress due to external force is dispersed and applied to each metal strand. However, in the actual shielding layer, since the metal wires are braided with different tensions, the stress due to the external force is applied to each metal wire unevenly. This means that stress concentrates on a specific metal strand.If one metal strand with concentrated stress breaks, then stress concentrates on another metal strand and breaks. As a result, the disconnection of the shielding layer progresses. If all the metal wires of the shielding layer are broken, the part far from the broken part is not grounded, which is very dangerous. The life of the currently used mobile cable is most often due to the disconnection of the shielding layer, and the strengthening of the shielding layer has been the point of extending the life of the mobile cable.

Accordingly, it is a primary object of the present invention to provide a moving cable capable of reducing concentration of stress on a metal wire of a shielding layer and suppressing disconnection of the metal wire.

[0005]

SUMMARY OF THE INVENTION The present invention achieves the above-mentioned object by combining metal wires in parallel instead of being arranged in parallel. That is, the moving cable of the present invention is characterized by including a shielding layer formed by using a stranded wire having a metal wire as a strand. Specific examples of the structure of the shielding layer include forming a stranded wire by twisting a plurality of metal wires, and braiding a natural fiber such as cotton or a synthetic fiber such as a polyamide resin with the stranded wire. Here, it is desirable that the twist pitch of the metal wire be 30 times or less the outer diameter of the twisted wire.

[0006]

Embodiments of the present invention will be described below. FIG. 1 is a schematic perspective view showing the structure of the cable of the present invention. As shown, the cable of the invention comprises a shielding layer 2 on a core 1 and a sheath 3 thereon. The core 1 is composed of a conductor, an inner semiconductive layer, an insulating layer, and an outer semiconductive layer (all not shown) in order from the center.

Here, the shielding layer 2 is made of tinned soft copper stranded wire 4
And a cotton yarn 5. That is, a plurality of tin-plated soft copper wires are stranded as metal wires, and this stranded wire is defined as one unit. Then, on the outer periphery of the core, the stranded wire 4 is wound in one direction, clockwise or counterclockwise, and both are woven so that the cotton yarn 5 is wound in the other direction to form an interwoven braid. The total cross-sectional area of the stranded wire 4 may be selected to be a value necessary for flowing the current induced in the cable shielding layer to the ground.

The pitch of the stranded wire 4 is 3 mm of the outer diameter of the stranded wire.
It is preferably 0 or less. The smaller the twist pitch of the strand is, the better, but if the twist pitch is reduced, the cost increases.

As described above, by twisting the strands rather than arranging them, the stress due to the external force is dispersed in the strands. The twisted wire has a higher mobility of each strand than the parallel strand, so that the stress applied to each strand can be greatly reduced. Further, the variation in the tension of the individual strands in the stranded wire decreases as the strand pitch of the strands decreases. Therefore, the stress can be further alleviated by reducing the twist pitch.

(Test Example) A bending test and a torsion test were performed on the cable having the above structure and the cable having the conventional structure, and the breaking state of the wires in the shielding layer was examined. As shown in FIG. 2, the test method of the bending test is to fix a predetermined length (shaded portion) of the cable 10, support the fixed portion on the rotating shaft 11, and attach a 10 kg weight 12 to the end of the cable. . Then, the cable was reciprocated in the range of 180 ° around the rotating shaft 11, and a cable having a radius of 50 mm was repeatedly applied to the cable 10 to examine the relationship between the number of times of bending and the resistance change of the shielding layer.

As shown in FIG. 3, the twisting test is performed by fixing one end of the cable 20 with a chuck 21 and setting the distance between the chuck 21 and the movable support 22 to a predetermined length. Is fixed to the movable support portion 22, and a 10 kg weight 24 is suspended from the other end of the cable 20 via the pulley 23. When the distance between the chuck 21 and the movable support portion 22 is L,
Since the cable twist angle (degree / m) is given by “90 degrees ÷ L”, in this example, L = 0.5 m and the twist of 180 ° / m can be given to the cable 20. Then, the chuck 21 is rotated within a range of ± 45 °, and the twist of the twist angle is repeatedly applied to the cable 20 to examine the relationship between the number of twists and the resistance change of the shielding layer.

In the embodiment, eleven tin-plated annealed copper wires having a diameter of 0.18 mm were stranded, and a cable having a shielding layer formed by weaving and knitting 12 stranded wires and 12 cotton yarns was used. Also,
In the comparative example, eleven 0.18 mmφ tin-plated annealed copper wires were juxtaposed, and a cable having a shielding layer formed by weaving and braiding 12 parallel copper wires and 12 cotton yarns was used.

The results of the bending test are shown in the graph of FIG. 4, and the results of the torsion test are shown in the graph of FIG. (A) of each figure shows the result of the example, and (B) shows the result of the comparative example. As shown in the graph, it can be seen that the resistance of the shielding layer increases as the number of times of bending (twisting) increases, and the number of broken tin-plated annealed copper wires increases. In the comparative example, the number of tests until all the wires were broken was 123,000 in the bending test and 11,000 in the torsion test, whereas in the example, the number of times was 150,000 and 32833. Thus, it can be seen that the effectiveness of the present invention has been demonstrated.

[0014]

As described above, according to the cable of the present invention, by using a copper stranded wire for the shielding layer of the braided structure, concentration of stress on a specific strand is reduced, and disconnection is suppressed. The life of the transfer cable can be extended.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view showing a configuration of a cable of the present invention.

FIG. 2 is an explanatory view showing a bending test method of a cable.

FIG. 3 is an explanatory view showing a twisting test method for a cable.

FIG. 4A is a graph showing a result of an example in a bending test, and FIG. 4B is a graph showing a result of the comparative example.

FIG. 5A is a graph showing the results of the example in the twist test, and FIG. 5B is a graph showing the results of the comparative example.

FIG. 6 is a plan view showing a braided structure of a shielding layer in a conventional moving cable.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Core 2 Shielding layer 3 Sheath 4 Tin-plated soft copper stranded wire 5 Cotton thread 10,20 Cable 11 Rotating axis 12,24 Weight 15 Thin copper wire 16 Collective element wire 17 Cotton thread 21 Chuck 22 Movable support part 23 Pulley

 ──────────────────────────────────────────────────続 き Continuation of the front page (71) Applicant 000002255 Showa Electric Wire & Cable Co., Ltd. 2-1-1 Oda Sakae, Kawasaki-ku, Kawasaki-shi, Kanagawa (72) Inventor Takashi Tanaka 1-1-3 Shimaya, Konohana-ku, Osaka-shi Sumitomo Electric Industries, Ltd.Osaka Works (72) Inventor, Kyokazu Ando 1 Higashi-Shinmachi, Higashi-ku, Nagoya City Inside Chubu Electric Power Company (72) Inventor Toshiaki Ito 18 Yanagimachi, Nagano City Chubu Electric Power Company (72) Invention Person Tetsu Kadoguchi 3-1-1, Sennen 3-chome, Minato-ku, Nagoya-shi Inside Toenec Co., Ltd. (72) Inventor Masahiro Yamada 2-1-1 Oda Sakae, Kawasaki-ku, Kawasaki City

Claims (2)

[Claims] 1. A moving cable comprising a shielding layer having a braided structure, wherein a twisted wire is woven into the shielding layer, and the twisted wire is formed by twisting a plurality of metal wires. Transfer cable. 2. The moving cable according to claim 1, wherein the twist pitch of the metal wires is 30 times or less the outer diameter of the twisted wire.