JPH0436905A - Shielding wire for pressure welding - Google Patents

Abstract

PURPOSE:To adhere the metal tape of a shielding layer to a drain wire by making up the drain wire of twisted wires of strands of tin plated annealed copper wire and forming one of the strands or a plurality thereof from thermoplastic strings and by method wherein the thermoplastic strings are molten when a sheath is extruded so that the molten strings and the metal tape forming a shielding layer are made to adhere. CONSTITUTION:A drain wire 3a made up of twisted wires of tin plated annealed wires is constituted of, for example, seven strands 6, and one strand 7 forming the external circumference of the drain wire 3a is formed from, for example, a polyethylene string of thermosetting plastic. Therefore, the polyethylene string 7 is molten by heat generated at the time of sheath extrusion and then heating of a core wire, so that the string 7 adheres to the metal tape forming a sheath layer formed longitudinally attaching to the external circumference of the string 7 and resultantly, the drain wire certainly adheres to the metal tape. It is thereby possible for the electric continuity between the drain wire 3a and the metal tape forming the shielding layer to be kept.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a shielded wire, particularly a shielded wire for pressure contact.

[Prior Art] FIG. 5 is a cross-sectional view showing the configuration of an example of a conventional shielded electric wire. That is, a central drain wire 3 and two insulated wire cores constituting a signal line in which a conductor 1 is coated with an insulator 2 are arranged parallel to each other on the left and right, and a metal tape is vertically placed on the outer periphery of the wire cores when extruding the sheath 5. A shield layer 4 is provided, and the outer periphery of the shield layer 4 is integrally covered with a sheath 5 by extrusion. Therefore, the entire circumference of the signal line composed of the left and right insulated wire cores is shielded by the shield layer 4, and the drain wire 3 is used to ground the shield layer 4 made of metal tape.

FIGS. 6(A) and 6(B) are a cross-sectional view and a side view of the end portion showing the state of pre-processing for press-welding the shielded wire. That is, the sheath 5) and the shield layer 4 at the ends of the shield wire are peeled off, but the drain wire 3 at the center is peeled off.
If the sheath 5 of the drain wire 3 is peeled off, pressure contact becomes impossible, so the sheath 5 and the shield layer 4 of the drain wire 3 are
As shown in Figure 3 (■3), leave it as is.

At this time, if the adhesion between the shield layer 4 of the metal tape and the insulator 2 is too strong, the insulator 2 will stretch when the shield layer 4 is peeled off, causing poor pressure bonding, so it is necessary to suppress the adhesion. Ta.

[Problems to be Solved by the Invention] As described above, the adhesion between the metal tapes of the sheath layer 4 made of metal tape in the drain wire portion and between the metal tapes and the drain wire is as shown in FIG. 7(A). (B
) As shown in Figure 2, the shield layer 4 is formed by vertically stacking the metal tape, so the adhesion is weak and it tends to come loose downwards, which may cause defects during the shield wire pressure welding work. There is a risk of it being damaged.

The present invention has been made in view of the above points, and provides an improved press-contact shielded wire that eliminates the drawbacks of the above-mentioned prior art (i.e., brings the drain wire and the metal tape of the shield layer into close contact with each other). The purpose is to

[Means and effects for solving the problem] This invention has the following features:
In a shielded wire consisting of an insulated core wire made of signal cotton and a drain wire, the drain wire (consisting of twisted wires of tinned annealed copper wire)
One or more of them are formed using thermoplastic plastic snack strings, and the above-mentioned
1. A shielded electric wire for pressure welding, characterized in that a plastic string is melted and stretched so as to be in close contact with a metal tape forming a shielding layer.

Further, the present invention is a shielded electric wire for press-fitting, which is formed by gap-winding a drain wire in a plastic dab coated with an adhesive.

Furthermore, the present invention provides a pressure welding method in which the drain wire is formed by injecting a hollow melt adhesive into the gap between the strands of the drain wire, and the outer periphery of the drain wire is wound with a brass weave gap. This is a shielded wire for use.

[Example] 1': This invention will be explained in detail based on the drawings.

FIG. 1 is a cross-sectional view showing the structure of a drain wire of a shielded electric wire for press-fitting according to an embodiment.

That is, the drain wire 3 is made of twisted tin-plated annealed copper wire.
A is composed of, for example, seven wires 6, and one wire 7 forming the outer periphery is formed using thermoplastic plastic, for example, polyethylene string. Therefore, the polyethylene string 7 melts during sheath extrusion due to heat during sheath extrusion, heating of the core wire, etc., and comes into close contact with the metal tape forming the sheath N4 formed longitudinally along the outer periphery. The drain wire 3 and the metal tape will surely come into close contact with each other. Furthermore, electrical continuity between the drain wire 3a and the metal tape forming the shield layer is maintained.

Instead of this polyethylene string 7, it is also possible to use a fabric coated with polyethylene L/N.

In addition, in the above example, one Poly-Goo I non-string 7 was used in place of one of the strands, but as a modification of this, a drain drain as shown in FIG. A drain wire may be formed by using three of the outer strands of the wire 3b as a bodied 1/in string 7, or a plurality of two or more cotton wires of the same number as the polyethylene string for the drain wire. Of course, you can change it (j).

Next, a second embodiment of the present invention will be described based on the cross-sectional view and side view of the drain wire shown in FIGS. 3(A) and 3(B). That is, the drain wire 3c is formed by gap-winding a thermoplastic glass coated with an adhesive, such as a polyethylene tape 8, around a stranded wire -1- made of a tinned annealed copper wire 6. The drain wire 3c grounds the shield layer 4 made of a metal tape formed on the outer periphery of the drain wire 3c, and the tape 8 coated with adhesive is formed by covering the sheath 5 by extruding the shield layer 4 made of the metal tape vertically. At this time, the metal tape and the drain wire 3c are brought into close contact with each other while maintaining electrical conduction, thereby preventing the drain wire 3 and the shield layer 4 made of the metal tape from coming apart during press-contact.

Next, a third embodiment of the present invention will be described based on FIG. That is, the drain wire 3d has a botmelt adhesive 9 in the gap between the wires 6 made of tin-plated annealed copper wire.
It was formed by pouring. Then, a thermoplastic plastic tape 8, for example, polystyrene tape 8, is gap-wound around the outer periphery as shown in FIG. 3(B). Therefore, the polystyrene tape 8 and the longitudinally laid metal tape forming the sheath layer 4 are brought into closer contact with each other more reliably due to the heat generated during sheath extrusion, and electrical continuity is also maintained.

[Effects of the Invention] As explained below, the shielded electric wire for pressure welding of the present invention comprises one or more thermoplastic plastic strings consisting of stranded drain wires, and a polystyrene tape coated with an adhesive. It is constructed by gap winding or by pouring a hot melt adhesive between the wires, so when the shield wire is pressure welded, the drain wire and the metal tape that makes up the shield layer are firmly attached while maintaining electrical continuity. Because of this, it does not come apart and reliability is dramatically improved.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a drain wire showing an embodiment of the present invention, FIG. 2 is a cross-sectional view of a modified drain wire, and FIGS. 3(A) and (E) are cross-sectional views of a drain wire of a modified example. A cross-sectional view and a side view of a drain wire showing a second embodiment, FIG. 4 is a cross-sectional view of a drain wire showing a third embodiment of the present invention, and FIG. 5 is a configuration of a conventional pressure-welding shielded wire. 6(A) and (B) are front and side views showing the state of pre-processing for pressure-welding the shielded wire, and FIG. 7(A) and (B) are the front FIG. 6 is a front view and a side view of the drain wire after processing. 1...Conductor 2...Insulator 3, 3a, 3b, 3c, 3
d-...Drain wire 4...Shield layer 5...Sheath 6...Element wire (tin-plated annealed copper stranded wire) 7...Thermoplastic plastic string 8...Plastic tape 9...Hot melt Adhesive Figure 1

Claims (3)

[Claims] (1) In a shielded wire composed of an insulated core wire and a drain wire, the drain wire is composed of strands of tin-plated annealed copper wire, and one or more of these strands are tied with a thermoplastic plastic string. A shielded electric wire for pressure welding, characterized in that the thermoplastic plastic string is melted by heat during sheath extrusion, core wire heating, etc., and is brought into close contact with a metal tape forming a shield layer. (2) A pressure welding shielded electric wire, characterized in that the drain wire is formed by gap-winding a plastic tape coated with an adhesive. (3) A pressure welding shielded electric wire characterized in that the drain wire is formed by pouring hot melt adhesive into the gap between the strands of the drain wire, and gap-wrapping a plastic tape around the outer periphery of the drain wire.