JPS6239546Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an improvement of a flat cable used as internal wiring of electronic equipment. As is well known, coaxial cores, which have an insulator on the center conductor and an outer conductor on the outer periphery, have excellent electrical properties, but are difficult to process and have poor flexibility. There were flaws.

Therefore, in order to create a wire core with improved terminal processing and flexibility without significantly deteriorating electrical characteristics, ground conductors are placed on both sides of the signal conductor, and these are integrally covered with an insulator with a rectangular cross section. A three-conductor wire core with a structure consisting of the following has been proposed and put into practical use.

On the other hand, a flat cable made by arranging multiple insulated wire cores in parallel and integrating them has a good space factor and is therefore widely used as an internal wiring material for electronic devices.

Therefore, when wiring the aforementioned three-conductor wire core within an electronic device, it is preferable to arrange a plurality of wire cores in parallel to form an integrated flat cable.

Conventionally, when creating a flat cable with three conductor wire cores, the three conductor wire cores were arranged closely in parallel, and heat was applied from above to melt the insulation of the three conductor wire cores and fuse the wire cores together. Ta.

However, in this case, no matter how much the dimensional accuracy of the three-conductor core was improved, the dimensional accuracy between the conductors in the flat cable deteriorated.

That is, when a three-conductor wire core is made into a flat cable, the insulation is heated to a temperature above its melting point in order to be fused, but at this time the volume of the insulation changes significantly.

This volume change of the insulator is particularly large in the case of fluorine resins (PFA, FEP, E-TFE, E-CTFE, etc.), and by applying heat above the melting point,
The dimensional accuracy of a three-conductor wire core changes, and dimensional accuracy cannot be achieved even if the cable is made into a flat cable.

Furthermore, when heat above the melting point is applied to fuse the three-conductor wire core, the insulator recrystallizes, increasing the adhesion strength with the conductor, which also has a negative effect on the stripability of the conductor.

It is an object of the present invention to provide a flat cable that eliminates the drawbacks of the prior art described above and has significantly improved dimensional accuracy at the terminal portion where terminal processing is required.

In other words, the gist of the present invention is to arrange a plurality of wire cores made of an insulator with a rectangular cross section on the outer periphery of a conductor in parallel, and heat-seal the adjacent wire cores only on the surface at a predetermined position in the length direction. The flat cable is characterized by being composed of:

In the above, it is important that the thermal fusion of adjacent cores is limited to the surface only, and that the contact portions of adjacent cores are not fused, resulting in dimensional accuracy between adjacent cores. This is a significant improvement.

By the way, the dimensional accuracy of the three-conductor wire core is the insulator width
The distance between the signal conductor and the ground conductor is 0.45±0.05, and the signal conductor is set at 0.635±0.01mm from the insulator end.

In addition, the dimensional accuracy when 50 of these three-conductor wire cores are flattened is 62.23± the distance between the signal conductors on both sides.
The dimensional accuracy must be 0.21mm, and the distance between opposing ground conductors of adjacent cores must be 0.37±0.05mm.

The insulator of the wire core in this invention is PFA, FEP, which is a material whose volume changes significantly above its melting point.
Although the main target is fluororesins such as E-TFE and E-CTFE, it is not limited thereto, and can also be applied to polyethylene and the like having similar properties.

Further, the core conductor of the present invention is not limited to three conductors, but can be similarly applied to one conductor, two conductors, or four or more conductors.

Next, one embodiment of the flat cable of the present invention will be further described with reference to the accompanying drawings.

Reference numeral 1 denotes a three-conductor wire core, in which three silver-plated annealed copper wires 4 with a diameter of 0.16 mm are arranged at a distance of 0.45±0.05 mm, and FEP is extruded and coated on the outer periphery as an insulator 5 with a rectangular cross section.

The thickness of the insulator 5 is 0.7 mm, and the width is 1.27±0.02 mm.

Prepare 50 of these three-conductor wire cores 1 with a length of 5 m, create terminal heat-sealed parts 1 of 80 mm at both ends, bind them with a cable band 2 in the middle, and wire core bundle part 3.
And so.

As shown in FIG. 2, the terminal heat-sealed portion 1 was heat-sealed 6 only to the upper and lower surfaces of the wire cores, and the contact portion 7 between adjacent wire cores was not fused. The method of manufacturing this terminal heat-sealed part 1 is to arrange 50 wire cores in parallel in contact with each other,
Heat was applied from the top and bottom using heating electrodes, and by adjusting the temperature, time, and pressure, only the surface on the electrode side was fused.

When a 50-core flat cable was manufactured in this way, the distance between the conductors at the center of the cores at both ends and the distance between the conductors between adjacent cores sufficiently satisfied the desired dimensional accuracy. It was confirmed that there were no problems in actual use.

It was also confirmed that there were no problems with the conductor stripping properties of the terminal.

Furthermore, since the middle part of the flat cable is a bundled part, the near-end crosstalk is improved to 1/2 and the far-end crosstalk to 1/4 compared to a tape wire that is flat all the way through, and it was confirmed that the shielding effect is great.

As explained above, the present invention makes it possible to provide a flat cable with excellent dimensional accuracy by heat-sealing only the surface of the insulated wire core.
Its practical value is great.

[Brief explanation of the drawing]

FIG. 1 is an explanatory plan view showing one embodiment of the flat cable of the present invention, and FIG. 2 is an explanatory cross-sectional view showing the end fused portion thereof. 1... Wire core terminal fused portion, 2... Binding band,
3... Wire core bundle portion, 4... Conductor, 5... Insulator, 6... Fused portion, 7... Non-fused portion.

Claims (1)

[Scope of utility model registration request] It is characterized by being constructed by arranging a plurality of wire cores made of an insulator with a rectangular cross section around the outer periphery of the conductor in contact with each other in parallel, and heat-sealing adjacent wire cores only on the surface at predetermined positions in the length direction. flat cable.