JPH0741053Y2 - Multi-core shielded cable - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a multi-core shielded cable used for general instrumentation, computers, etc., and in particular, a multi-core shield with improved variation in electrical characteristics between cable core layers. It is about cables.

[Prior Art] Conventionally, multi-core shielded cables for general instrumentation and computers have, in terms of handleability, a thin, light and flexible cable, good terminal processability, and excellent electrical characteristics. In view of this, it is required that the capacitance be low, the characteristic impedance is high, the transmission characteristic is good, the shield effect is good, and the price is low.

Recently, with the spread of electronic devices, FMI countermeasures (electromagnetic interference countermeasures) have become an essential condition, and cable shields have been emphasized.

From such a point, the conventional multi-core shielded cable has a laminated tape composed of a metal foil tape and a plastic tape on the outer periphery of a cable core in which a plurality of insulated core wires are twisted in multiple layers so that the plastic tape is on the cable core side. It is known that it is formed by winding, and a braid and a jacket made of a metal wire are sequentially provided on the outer circumference of a laminated tape.

[Problems to be Solved by the Invention] However, in the above-mentioned conventional multi-core shielded cable, since the shield structure has a laminated tape on the inner side and a braid on the outer side, the insulation core wire of the inner layer and the insulation core wire of the outermost layer are There is a problem in that there are large variations in electrical characteristics and there is a difference of about 10Ω in characteristic impedance. This is because the outermost insulation wire of the cable core closest to the shield was electrically affected by the shield. That is,
This is due to the proximity effect and the reaction effect of the shield, and was greatly affected by the thin metal foil tape applied to the outer circumference of the outermost insulating core wire.

An object of the present invention is to provide a multi-core shielded cable, which improves the above-mentioned drawbacks of the prior art and improves the variation in electrical characteristics between cable core layers.

[Means for Solving the Problems] In the present invention, a braid made of a metal wire is provided on the outer circumference of a cable core in which a plurality of insulating core wires are twisted or assembled in multiple layers, and a metal foil tape and a plastic are provided on the outer circumference of the braid. In a multi-core shielded cable in which a metal foil tape is wound so that the metal foil tape is on the braid side and a jacket is provided on the outer circumference of the laminate tape, the thickness of the braid is formed to be thicker than the laminate tape. It was done.

[Operation] The multi-core shielded cable of the present invention has the shield structure formed by braiding the inside and winding the laminate tape vertically or horizontally so that the outermost layer of the cable core closest to the shield is formed. Since a thick braid is provided on the outer periphery of the insulation core wire, it can be reduced that the insulation core wire is electrically affected by the proximity effect of the shield, the reaction effect, etc. It is possible to reduce variations in the electrical characteristics of the outermost insulating core wire.

[Embodiment] FIG. 1 shows an embodiment of the multi-core shielded cable of the present invention.

1 is a conductor, 2 is an insulator, 3 is an insulated core wire, 4 is a twisted pair wire, 5
Is an inner layer, 6 is an outer layer, 7 is a cable core, 8 is a braid, 9 is an aluminum foil tape, 10 is a polyester tape, 11 is a laminated tape, and 12 is a jacket.

Conductor 1 is made of tin-plated annealed copper wire with an outer diameter of 0.381 mm,
The outer periphery is extruded and covered with an insulator 2 of thermoplastic resin such as polyethylene having a thickness of 0.25 mm to form an insulating core wire 3. A cable core 7 is formed as an outer layer 6 by providing 14 pairs of twisted wires 4 on an inner layer 5 formed by rounding 11 pieces of paired twisted wires 4 obtained by twisting the insulated core wires 3 in pairs. On the outer periphery of the cable core 7, there is provided a braid 8 in which tin-plated annealed copper wire having a wire diameter of 0.12 mm is woven at a density of 85%. The laminating tape 11 is composed of an aluminum foil tape 9 having a thickness of 10 μm and a polyester tape 10 having a thickness of 13 μm. The aluminum foil tape 9 is wound around the outer periphery of the braid 8 side by side so that the aluminum foil tape 9 is on the braid 8 side. Is formed. At this time, the aluminum foil tape 9 may be coated with an adhesive in order to facilitate the terminal processing and to improve the flexibility of the cable. The jacket 5 is made of a thermoplastic resin such as polyvinyl chloride having a thickness of 0.81 mm, and the outer periphery of the laminating tape 11 is extrusion-coated.

As a result of measuring the characteristic impedance of the multi-core shielded cable manufactured in this way, the average inner-layer insulation core wire
93.8Ω, the average of the outer core insulation wire is 92.1Ω.

As a comparative example, as a result of measuring the characteristic impedance of a multi-core shielded cable in which the same laminated tape and braid as the above example were sequentially provided on the outer periphery of the cable core, the inner layer insulation core wire was 92.6Ω on average, and the outer layer insulation core Line averages 88.6
Ω.

[Effects of the Invention] As described above, the multi-core shielded cable of the present invention has a shield structure in which the inner side is braided and the outer side is laminated tape on the outer periphery of the cable core.
Since the outermost layer of the cable core closest to the shield is provided with a thick braid on the outer periphery of the insulation core wire, the insulation core wire is less affected by electrical effects such as proximity effect and reaction effect of the shield. Therefore, there is an effect that variations in electrical characteristics between the inner-layer insulating core wire and the outermost-layer insulating core wire can be reduced.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an embodiment of the multi-core shielded cable of the present invention, (1) is a schematic view and (2) is a sectional view. 1: Conductor, 2: Insulator, 3: Insulated core wire, 4: Twisted wire, 5: Inner layer, 6:
Outer layer, 7: Cable core, 8: Braid, 9: Aluminum foil tape, 10: Polyester tape, 11: Laminated tape, 1
2: Jacket.

Claims (1)

[Scope of utility model registration request] 1. A braid made of a metal wire is provided on the outer circumference of a cable core in which a plurality of insulating core wires are twisted or assembled in multiple layers,
A multi-core shielded cable in which a laminate tape composed of a metal foil tape and a plastic tape is wound around the outer periphery of the braid so that the metal foil tape is on the braid side, and a jacket is provided on the outer periphery of the laminate tape. A multi-core shielded cable having a thickness thicker than the laminated tape.