JP2002231058A - Electric cable, and wire harness composed of electric cable group - Google Patents

Abstract

PROBLEM TO BE SOLVED: To impart a wire hardness with flexibility. SOLUTION: The electric cables, which are the constituents of the wire harness connected to an automobile, is formed by arranging an insulation resin covering layer in the outer periphery of a plurality of twisted core wires, and arcuate crest and valley are formed alternately in continuous fashion. The crest and the valley are extended in the axial direction, and many of the electric cables are bundled and banded together by winding a tape around the outer periphery. The contact pressure between adjacent electric cables are reduced by increasing contacting part of adjacent electric cables, and the wire harness is enabled to bend flexibly.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric wire and a wire harness composed of the electric wire group. Is to be able to do.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG.
Has an outer periphery of a core wire 1 formed by twisting a number of strands 1 ′ covered with an insulating resin 2, and the outer peripheral surface of the insulating resin 2 has a perfect circular shape. The reason why a large number of strands 1 'are twisted to form a multi-core wire type is to provide the wire w with more flexibility in bending than a single-core wire.

As shown in FIG. 6 (B), a wire harness W / H for bundling a large number of the electric wires w, winding a tape 3 around the outer periphery and binding them together and routing them to an automobile or the like is constituted.

When the wire group W is wound and fastened with the tape 3 as described above, the outer peripheral surface of the wire w has a substantially perfect circular shape, and therefore, as shown in FIG. The contact portion becomes a point contact (a line contact in the length direction) in a cross section, and contacts at one point C in the drawing.

When the tape 3 is strongly wound, a load is concentrated on one point C, the insulating resin 2 is deformed, and the state changes from a point contact state to a surface contact state. Also, when the wire harness W / H needs to be bent and routed, the wire group W at the bending point is also required.
A load is applied to the (especially the inner wire w), and the adjacent wires come into surface contact at one place.

[0006] As shown in Fig. 5, when the contact changes from the point contact to the surface contact, the frictional force generated between the electric wires rapidly increases, and the adjacent electric wires w are hardly slipped with each other. W / H is difficult to bend.

In order to solve the above problem, as shown in FIG. 7, a corrugated tube which can be easily bent in a bellows shape instead of wrapping a wire group W with a tape 3 for a wire harness which needs to be bent is used. There is a case where the electric wire group is sheathed in 5.

[0008]

However, when the wire group W is covered with the corrugated tube 5, the outer diameter of the wire harness is increased by the thickness of the corrugated tube as compared with the case where the wire is wound by tape. Therefore, it is necessary to increase the wiring space for the wiring harness, but if the wiring space is narrow, it is not possible to cover the wiring harness with a corrugated tube.

The present invention has been made in view of the above-mentioned problem, and has an advantage in that even when a group of electric wires is wound with a tape, bending flexibility is provided. The challenge is to do.

[0010]

In order to solve the above-mentioned problems, according to the present invention, first, an insulating resin coating layer is provided on the outer periphery where a large number of core wires are twisted, and the outer periphery of the insulating resin coating layer is provided. An electric wire is provided in which arc-shaped peaks and valleys are formed alternately and continuously on a surface, and the peaks and valleys extend in the axial direction.

The above-mentioned electric wire has an insulating resin coating layer having the same thickness as that of the conventional electric wire, so as to secure insulation and a core wire protecting function required for the electric wire, and to be integrated with the insulating resin coating layer on the outer peripheral surface of the insulating resin coating layer. An arc-shaped peak and a valley are alternately and continuously provided. The height of the ridge projecting from the outer peripheral surface of the insulating resin coating layer is minimized within the range in which the ridge can appear in order not to increase the outer diameter of the electric wire.

The ridges and valleys are formed by providing an uneven portion on the mold surface of the mold when the core wire is passed through the mold and the insulating resin coating layer is formed on the outer periphery thereof by drawing.
It can be easily formed with the ridges and valleys extending continuously in the axial direction.

According to a second aspect of the present invention, there is provided the electric wire according to the first aspect, wherein a large number of the electric wires are bundled, and the outer peripheral surface thereof is tape-tied and bound, and a contact portion between adjacent electric wires of the bundled electric wires is provided. The present invention provides a wire harness including a group of electric wires configured to be able to flexibly bend by reducing the contact pressure between the electric wires.

The relationship between the contact pressure and the frictional force between the wires bundled as a wire harness is as shown in FIG. 5A. That is, when the contact form of the electric wire changes from the point contact of S to T in the drawing to the surface contact in the TU direction, the frictional force increases rapidly.
When the friction coefficient is constant, as shown in FIG. 5B, the frictional force increases in proportion to the contact area, but the friction coefficient differs between point contact and surface contact. The point of contact at a plurality of locations reduces the frictional force generated between the electric wires as compared with the point contact at a plurality of locations. That is, assuming that the frictional force between the wires that are in surface contact at one point is P1, the sum P2 of the frictional forces when two wires are in point contact is P1> P2.

When the wire harness is configured as described above, the contact between adjacent wires is such that the ridge of one wire fits into the valley of the other wire, so that the ridge of one wire is connected to the other wire. Point contact with both sides of the valley portion at two points. Therefore, even if the wire harness is formed by tape-wrapping the wire group and the wire harness is bent to increase the contact pressure between the wires, the contact positions are dispersed at two points. The pressure is reduced and the peaks do not collapse at each point of contact, maintaining point contact. As a result, as described above, the frictional force between the electric wires is reduced, the electric wires become slippery in the axial direction, and even when the wire harness is wound with a tape, flexibility can be imparted and the wire harness can be easily bent.
In addition, the electric wire group is positioned relative to each other by the fitting of the peaks and the valleys, and the movement in the circumferential direction is regulated. Therefore, when the band clamp is wound around the wire harness, the electric wire does not move in the circumferential direction, and the band winding operation becomes easy.

As described above, even if the electric wire group is wound by tape and bound without using a corrugated tube, the wire harness can be easily bent, and the wire harness can be bent in a narrow wiring space. The rope becomes possible.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an electric wire 10 of the present invention,
The electric wire 10 is formed by twisting a number of strands 11 to form a core wire 12,
The outer periphery of the core wire 12 is covered with an insulating resin coating layer 13, and small arc-shaped peaks 13 a and valleys 13 b are formed alternately and continuously on the outer peripheral surface of the insulating resin coating layer 13. The lower apex of the valley 13 b is made to coincide with the outer peripheral surface of the insulating resin coating layer 13. The ridges 13a and the valleys 13b extend in the axial direction of the electric wire 10.

The state in which the ridge 13a of the electric wire 10 does not protrude, that is, the thickness t (the valley 13
b) is set to the same thickness as a conventional electric wire. The thickness of the insulating resin coating layer 13 is defined to a predetermined thickness by the diameter of the core wire 12. The projecting height H of the peak 13a is such that the outer diameter of the electric wire including the peak 13a is slightly larger than the conventional outer diameter of the electric wire. Specifically, the core wire 12
Is 100 mm 2, the outer diameter of the insulating resin coating layer 13 is 1.2 mm, and the outer diameter when the peak 13 a protrudes is 1.
The protrusion height H of each peak 13a is 0.1 mm.

It is preferable to form a large number of peaks 13a on the outer peripheral surface of the electric wire by reducing the pitch of the peaks 13a. In the case of an electric wire having a small outer diameter, as shown in FIGS. The peaks 13a may be provided at 90-degree intervals.

In the above-mentioned electric wire 10, the insulating resin coating layer 13 having a specified thickness t is provided on the outer peripheral surface of the core wire 12, so that the same insulation and core wire protecting function as those of the conventional electric wire can be provided.

FIG. 3 shows a wire harness 100 according to an embodiment of the present invention, in which a large number of the electric wires 10 shown in FIG.

In the wire harness 100, the electric wire 10
1 is configured as shown in FIG. 1, and as shown in FIG. 3C, the adjacent electric wires 10-1 and 10-2
-1 of the outer peripheral surface of the insulating resin coating layer 13 of FIG.
The peak 13a of 0-1 contacts two points A and B on both sides of the valley 13b of the electric wire 10-2.

As shown in FIG. 4, when the wire harness 100 having the above-described configuration is to be installed in an automobile, if it is necessary to bend the adjacent wires 10-1 and 10-2, two points A, B
, The bending load is distributed to the two points A and B. Therefore, the contact pressure applied to these two points A and B becomes small, and the two points A and B maintain the state of point contact and do not come into surface contact. Frictional force can be reduced. As a result, the adjacent electric wires 10-1 and 10-2 become slippery with each other, and the wire harness 100 can be flexibly bent.

As described above, since the electric wire 10 is a multi-core wire type, the flexibility of the electric wire 10 itself is ensured, and the flexibility is ensured even when these electric wires 10 are wrapped with a tape. The wire harness can be bent and routed even in a place where the routing space is narrow without using the wire harness.

[0025]

As is apparent from the above description, according to the present invention, peaks and valleys are provided on the outer peripheral surface of an electric wire, and these electric wires are bundled and tape-wound to form a wire harness. By increasing the number of contact portions between the electric wires and dispersing the contact pressure and maintaining the point contact at each contact position, the frictional force generated between the electric wires can be reduced. As a result, even if a large number of electric wires are bundled and tape-wound, each electric wire becomes slippery, and the wire harness is provided with flexibility and can be easily bent at a bending position.

Therefore, even in a bent portion of a narrow space where the corrugated tube cannot be routed when the corrugated tube is covered, the wire harness in which the wire group is wound with the tape can be bent while being bent.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of an electric wire of the present invention.

FIGS. 2A and 2B are schematic diagrams showing a modified example of an electric wire.

FIG. 3 shows an embodiment of the wire harness of the present invention,
(A) is a perspective view, (B) is a partially enlarged sectional view, and (C) is a partially enlarged sectional view showing a contact form between adjacent electric wires.

FIG. 4 is a drawing showing a bent portion of the wire harness.

FIG. 5A is a diagram showing a relationship between contact pressure and frictional force,
(B) is a diagram showing the relationship between the contact area and the frictional force.

6A is a perspective view showing a conventional electric wire, FIG. 6B is a perspective view of a wire harness obtained by binding the conventional electric wires, and FIG.
FIG. 3 is a partially enlarged sectional view showing a contact state of an adjacent electric wire.

FIGS. 7A and 7B are cross-sectional views showing another conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 3 Tape 10 Electric wire 11 Element wire 12 Core wire 13 Insulating resin coating layer 13a Mountain part 13b Valley part 100 Wire harness

Claims (2)

[Claims] An insulating resin coating layer is provided on an outer periphery where a number of core wires are twisted, and arc-shaped peaks and valleys are alternately formed on an outer peripheral surface of the insulating resin coating layer, An electric wire characterized in that these peaks and valleys extend in the axial direction. 2. An electric wire according to claim 1, wherein the electric wires are bundled together, and the outer peripheral surface thereof is taped and tied, and a contact portion between adjacent electric wires of the bundled electric wires is increased to reduce a contact pressure between the electric wires. Wire harness consisting of a group of wires that can be flexibly bent.