JP2007005096A - Shielded electric wire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a shielded electric wire with a high environment maintenance property and excellent fire retardancy. <P>SOLUTION: Since a metal tape 21 superposedly wound over a metal tape layer 20 between a shielding layer 13 and a sheath layer 14 is folded so that metal parts 22 come in direct contact with each other, the metal parts 22 are closely adhered with each other to block the inside, even if a resin tape part 23 of the metal tape 21 is burned or contracted at combustion of the shielded wire 10. This can stop inflammable gas from blasting off from inside, enabled to prevent spread of fire inside. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a shielded electric wire, for example, a shielded electric wire having high flame retardancy without adversely affecting the environment.

  Conventionally, the sheath layer of shielded wire contains PVC (polyvinyl chloride), and the halogen element (for example, chlorine) contained in PVC has an adverse effect on the environment when burned. The demand for halogen-free electric wires that do not contain halogen elements is increasing. Therefore, a shielded electric wire that does not adversely affect the environment has been proposed (see, for example, Patent Document 1). However, if the sheath does not contain a halogen element, the flame retardancy is inferior to that containing a halogen element, so that it has been desired to maintain the flame retardancy.

As shown in FIG. 5, the shielded electric wire 100 disclosed in Patent Document 1 is provided with an insulating layer 103 made of crosslinked polyethylene or the like on a conductor 101 via an internal semiconductive layer 102, and an external semiconductive layer thereon. A cable core 105 composed of the layer 104 is provided inside. And, on the outside of the cable core 105, a wire shield 106 in which a large number of copper thin wires are horizontally wound is provided, and on the outside thereof, a laminate tape 107 provided with a heat fusion layer on one side of an aluminum tape, A heat-shielding layer is formed by providing the heat-fusible layer with the vertical attachment or the like facing outward. Furthermore, the outermost layer on the outer side of the laminate tape 107 is covered with a plastic sheath 108 that does not contain a halogen element, and is provided so as to be integrated with the laminate tape 107 via a heat-sealing layer.
Japanese Patent Laying-Open No. 2001-6446 (FIG. 1)

In the shielded electric wire 100 disclosed in Patent Document 1, by using a non-halogen material that does not contain a halogen element as the material of the plastic sheath 108, generation of harmful substances such as chlorine gas and dioxin during combustion is prevented. In addition to preventing adverse effects on the environment, the water-shielding property is improved by laminating the laminate tape 107 to which the aluminum tape is attached.
However, the laminating tape 107 is a material that shrinks greatly upon burning, and the laminating tape 107 always exists between the aluminum tapes that have been wound around each other. There was a problem that a gap was formed in the portion, and combustion gas from the inner core was ejected from this gap, and combustion could continue.

  An object of the present invention is to provide a shielded electric wire having high environmental conservation and excellent flame retardancy.

  In order to achieve the above-described object, a shielded electric wire according to the present invention includes a central conductor disposed at the center, an insulating coating layer outside the central conductor, a shielding layer outside the insulating coating layer, and the shield. A shielded electric wire having a metal tape layer outside the layer and a sheath layer made of a non-halogen material outside the metal tape layer, the metal tape layer bonding the metal portion and the resin tape portion together The metal tape to be formed is formed by wrapping so that the metal portion is inside, and the metal tape is bent so that the metal portions are in contact with each other at the overlap portion.

  In the shielded electric wire configured in this way, the metal tape overlaid on the metal tape layer between the shield layer and the sheath layer is bent so that the metal portions are in direct contact with each other. Even if the resin tape portion of the metal tape burns or contracts during the combustion, the metal portions are in close contact with each other to block the inside. For this reason, it can prevent that the combustible gas which gasified because the insulation coating layer was high temperature from the inside of a metal tape layer can be ejected, and can spread to the inside.

  Moreover, the shielded electric wire according to the present invention is that a plurality of insulated conductor wires are twisted.

  In the shielded electric wire configured in this way, by spreading a plurality of insulated conductor wires, even if there is a gap inside the shield layer, it is possible to prevent the inside from spreading.

  According to the present invention, the environmental protection is maintained by forming the sheath layer from a non-halogen material, and the metal portions of the metal tape are connected to each other in the metal tape layer between the shield layer and the sheath layer when the shielded electric wire is burned. Is directly contacted and blocks the inside thereof, so that it is possible to provide a shielded electric wire capable of enhancing the flame retardancy.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments according to the present invention will be described in detail with reference to the drawings.
FIG. 1 is a cross-sectional view showing an embodiment of the shielded electric wire according to the present invention, FIG. 2 is a perspective view of a metal tape, and FIG. 3 is a cross-sectional view showing a state in which the metal tape is overwrapped.

  As shown in FIG. 1, a shielded electric wire 10 according to an embodiment of the present invention includes a central conductor 11 disposed in the center, an insulating coating layer 12 outside the central conductor 11, and an outer coating layer 12 outside the insulating coating layer 12. A shielded electric wire 10 having a shield layer 13, a metal tape layer 20 outside the shield layer 13, and a sheath 14 layer made of a non-halogen material outside the metal tape layer, the metal tape layer 20 being The metal tape 21 formed by laminating the metal portion 22 and the resin tape portion 23 is formed by overlappingly winding the metal portion 22 so that the metal portion 22 is on the inside. 22 is bent so that they are in contact with each other (see FIG. 3).

The metal tape layer 20 is obtained by winding a metal tape 21 as shown in FIG. 2 on a part of the outer side of the shield layer 13 as shown in FIG.
As shown in FIG. 2, the metal tape 21 is bonded to a metal portion 22 such as copper foil or aluminum foil and a resin tape 23 such as polyethylene terephthalate so that the metal portion 22 is located outside. For example, it is bent into a J-shaped cross section. As shown in FIG. 3, the metal tape layer 20 is formed by wrapping the metal tape 21 on the outside of the shield layer 13 so as to partially overlap.
At this time, the metal portion 22 of the metal tape 21 that has been wound first and the metal portion 22 of the metal tape 21 that has been wound next are overlapped and wound outward so as to directly contact each other at the overlapping portion 22a. Thus, the metal tape layers are in direct contact with each other at the overlapping portion. The folding width of the metal tape is preferably 1/5 to 3/4 of the tape width. If the width of the overlapping portion is 1/5 or more of the tape width, it seems that the VW-1 vertical combustion test method (US UL standard) can be cleared. If the overlapping portion is too large, the productivity is lowered, so it is realistic that the width of the overlapping portion is at most 3/4.

The center conductor 11 is usually made of standard annealed copper wire and is formed by twisting a plurality of wires.
In addition, as shown in FIG. 4, a plurality of insulated conductor wires can be twisted to form a shield layer on the outer periphery thereof. Although two-core twist is shown in the figure, three or more cores may be twisted, or a single core may be used.
For the insulating coating layer 12, for example, heat-resistant polyethylene can be used.
Moreover, the shield layer 13 can be formed by, for example, laterally winding an annealed copper wire. It can also be a braided shield. With or without tin plating.
In addition, for example, a flame retardant polyolefin such as flame retardant polyethylene can be used for the sheath layer 14, and a flame retardant such as a metal hydroxide, a flame retardant aid, or the like can be appropriately blended.

Note that the shielded electric wire 10 of the present invention is not limited to the above-described embodiment, and appropriate modifications, improvements, and the like are possible.
For example, in the embodiment described above, the bent shape of the metal tape 21 is a J-shape, but this is an example, and any shape having the same action and effect can be applied, for example, an S-shape. .
In addition, the materials exemplified in the central conductor 11, the insulating coating layer 12, the shield layer 13, the sheath layer 14 and the like are arbitrary and are not limited as long as the present invention can be achieved.

  As described above, the shielded electric wire according to the present invention maintains the environmental conservation by forming a sheath layer from a non-halogen material, and at the time of burning the shielded electric wire, a metal tape layer between the shield layer and the sheath layer. Since the metal parts of the metal tape are in direct contact with each other to block the inside, it has the effect of increasing the flame retardancy and is useful as a highly flame retardant shielded wire without adversely affecting the environment .

It is sectional drawing which shows embodiment of the shielded electric wire which concerns on this invention. It is a perspective view of a metal covering resin tape. It is sectional drawing which shows the state which piled up the metal coating resin tape. It is a 2-core twisted center conductor, (A) is a perspective view, (B) is sectional drawing. It is sectional drawing which shows the conventional shielded electric wire.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Shield electric wire 11 Center conductor 12 Insulation coating layer 13 Shield layer 14 Sheath layer 20 Metal-coated resin tape layer 22 Metal part 22a Overlapping part

Claims (2)

A central conductor disposed in the center; an insulation coating layer outside the center conductor; a shield layer outside the insulation coating layer; a metal tape layer outside the shield layer; and a non-halogen outside the metal tape layer A shielded electric wire having a sheath layer made of a system material,
The metal tape layer is formed by wrapping a metal tape formed by bonding a metal part and a resin tape part so that the metal part is inside,
The shielded electric wire, wherein the metal tape is bent so that the metal portions are in contact with each other at an overlapping portion.   2. The shielded electric wire according to claim 1, wherein a plurality of conductor wires coated with insulation are twisted.

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