JP2007299558A - Electric cable - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric cable improved in bending performance in order to wire in a place where a bending movement occurs frequently. <P>SOLUTION: The electric cable 10 is provided with a plurality of electric wires 11 consisting of a conductor 21 and an insulating layer 22 and a sheath 13 to cover the plurality of electric wires 11. Grooves 23 are formed on the surface of the insulating layer 22 of the electric wires 11 along the longitudinal direction of the electric wires 11. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electric cable including a plurality of electric wires such as a power supply line and a signal line, and more particularly to an electric cable excellent in flexibility.

  With the electrification of automobiles, electric cables equipped with power supply lines and signal lines are being routed where they are subject to much vibration and bending of automobiles.

  FIG. 4 shows an example of a conventional electric cable. The electric cable 40 is composed of four electric wires 41 such as a power supply line and a signal line, an outer winding 42 of the outer periphery of the four electric wires 41, and a sheath 43 covering the outer periphery. The four electric wires 41 are twisted and bundled. The sheath 43 is made of a rubber material such as EPDM and a resin such as polyurethane, and has a substantially circular cross section. There may be a case where an electric shield layer made of a metal braided wire or the like is provided between the four electric wires 41 and the sheath 43.

  5A and 5B are a cross-sectional view and an external view of an electric wire serving as a power supply line or a signal line. The electric wire 50 is provided with an insulating layer 52 around a stranded wire obtained by twisting a plurality of conductors 51 (seven in this example). Each conductor 51 is configured by bundling a large number of strands made of thin copper wires. The insulating layer 52 is made of a resin such as polyethylene, vinyl chloride, or ETFE, and has a substantially circular cross section. The diameter of the strands, the number of strands that are bundled to form a conductor, and the number of conductors that form a stranded wire are set according to the use of the power supply line and signal line and the required characteristics.

In order to improve the flexibility (easy to bend) of an electric cable, various structures have been studied. (For example, Patent Documents 1 and 2)
JP 2005-166610 A JP-A-2005-203117

  Electrical cables that are routed where automobiles frequently undergo bending motion are required to have better flexibility.

  Therefore, an object of the present invention is to provide an electric cable with improved flexibility.

  In order to achieve the above object, an electric cable of the present invention is an electric cable comprising a plurality of electric wires made of a conductor and an insulating layer, and a sheath covering the plurality of electric wires, and the length of the electric wire on the surface of the insulating layer of the electric wire. A groove along the direction is formed.

  The bendability of the electric cable can be improved.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Electric cable)
FIG. 1 shows an embodiment of the electric cable of the present invention. The electric cable 10 includes four electric wires 11 such as a power supply line and a signal line, a presser winding 12 on the outer periphery of the four electric wires 11, and a sheath 13 covering the outer periphery. The four electric wires 11 are twisted and bundled. The sheath 13 is made of a rubber material such as EPDM and a resin such as polyurethane, and has a substantially circular cross section. In some cases, an electric shield layer made of a metal braided wire or the like is provided between the four electric wires 11 and the sheath 13.

(Electrical wire)
2A and 2B are a cross-sectional view and an external view of an electric wire serving as a power supply line or a signal line. The electric wire 20 is provided with an insulating layer 22 around a stranded wire obtained by twisting a plurality of conductors 21 (seven in this example). Each conductor 21 is configured by bundling a large number of strands made of copper or copper alloy thin copper wire. The insulating layer 22 is made of a resin such as polyethylene, vinyl chloride, or ETFE, and has a substantially circular cross section. The diameter of the strands, the number of strands that are bundled to form a conductor, and the number of conductors that form a stranded wire are set according to the use of the power supply line and signal line and the required characteristics.

(groove)
In the present embodiment, a groove 23 along the longitudinal direction of the electric wire is formed on the surface of the insulating layer in all electric wires such as a power supply line and a signal line. The grooves 23 are formed at a plurality of positions at equal intervals on the surface of the insulating layer 22 of the electric wire 20. As shown in FIG. 2B, the groove 23 is formed linearly along the longitudinal direction of the electric wire 20. Each groove 23 has a substantially rectangular cross section. In addition, you may form a groove | channel spirally along the longitudinal direction of an electric wire. As shown in FIGS. 3A and 3B, the groove may have a U-shaped cross section or a wavy cross section.

(Production method)
The electric wire is formed by injecting an insulating layer material around the stranded wire in the die from the outside of the extrusion die, applying and curing the strand while inserting the stranded wire of the conductor into the extrusion die. An uneven shape is provided on the inner peripheral surface of the extrusion die through which the stranded wire is inserted. Thereby, a groove is formed on the surface of the insulating layer. What is necessary is just to set the uneven | corrugated shape of the internal peripheral surface of die | dye according to the shape of the groove | channel to form. In the case of forming a spiral groove, the insulating layer may be formed while rotating a die with respect to the stranded wire.

(Function)
When the electric cable is bent, the electric wires such as the signal line and the power line move relative to each other while being in contact with each other. In this embodiment, since the groove | channel is formed in the surface of an electric wire, the frictional force at the time of mutually contacting falls. Accordingly, the relative movement of the electric wires while being in contact with each other at the time of bending is facilitated, and the flexibility of the electric cable is improved.

  Moreover, since the groove | channel is formed in the surface of an electric wire, the clearance gap by a groove | channel arises in an electric cable. This gap has an effect of improving air permeability in the electric cable. Thereby, the bad influence of the expansion | swelling and shrinkage | contraction by the heat | fever at the time of use of an electric cable can be reduced.

(Modification)
The present invention is not limited to the electric cable of the above-described embodiment, but can be applied to the shape, size and number of electric wires such as a power supply line and a signal line, the arrangement of electric wires in the sheath, etc. designed according to the application purpose. .

  In the above embodiment, the electric cable has a sheath in which all the electric wires are provided with grooves, but a part of the electric wires may be provided with grooves.

(Application examples)
The electric cable of the present invention can be used as an electric cable connected to a movable device of a robot or an automobile. In automobiles, the present invention can be applied to electric cables that are frequently subjected to vibration and bending, such as electric brake harnesses and harnesses for in-wheel motors.

It is sectional drawing of the electric cable of embodiment of this invention. BRIEF DESCRIPTION OF THE DRAWINGS It is a figure of electric wires, such as a power wire and a signal wire | line of embodiment of this invention, (a) is sectional drawing, (b) is an external view. It is a cross-sectional enlarged view of the groove | channel of the modification of this invention, (a) is a groove | channel with a U-shaped cross section, (b) is a groove | channel on a cross-sectional wave. It is a sectional view of a conventional electric cable. It is a figure of electric wires, such as a power wire and a signal wire of a prior art, (a) is a sectional view and (b) is an appearance figure.

Explanation of symbols

10, 40 Electric cable 11, 20, 41, 50 Electric wire such as power line and signal line 12, 42 Presser winding 13, 43 Sheath 21, 51 Conductor 22, 52 Insulating layer 23 Groove

Claims (9)

In an electric cable comprising a plurality of electric wires made of a conductor and an insulating layer and a sheath covering the plurality of electric wires,
An electrical cable, wherein a groove along the longitudinal direction of the electric wire is formed on a surface of the insulating layer of the electric wire.   The electric cable according to claim 1, wherein a plurality of the grooves are formed at equal intervals in a circumferential direction of the surface of the insulating layer of the electric wire.   The electric cable according to claim 1, wherein the groove is formed linearly along a longitudinal direction of the electric wire.   The electric cable according to claim 1, wherein the groove is provided in a spiral shape along a longitudinal direction of the electric wire.   The electric cable according to claim 1, wherein the groove has a rectangular cross section.   The electrical cable according to claim 1, wherein the groove is formed in a substantially U-shaped cross section.   The electrical cable according to claim 1, wherein the groove is formed in a corrugated cross section.   The electrical cable according to claim 1, wherein the groove is formed in all of the plurality of electric wires.   The electric cable according to claim 1, wherein the groove is formed in a part of the plurality of electric wires.

Images