JPH0239290Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention is applicable to flat cables used as internal wiring of electronic equipment such as computers, and more specifically, to ease of wiring work, electrical characteristics, and terminal processing workability. This invention concerns the improvement of an excellent flat cable.

[Prior Art] Excellent electrical properties are required for internal wiring materials of electronic devices such as computers, and the applicant of this application has developed a cable structure that satisfies this requirement by using foamed fluororesin as an insulator. We are first proposing a cable using .

In other words, this cable consists of a central conductor, a highly foamed fluororesin insulator provided around its outer periphery, a drain wire attached vertically to this, a shielding tape layer provided around the outer periphery of these, and a fluorine resin insulator provided around the outer periphery of the center conductor. A plurality of cable cores made of resin jacket layers are arranged in parallel, and adjacent cores are fused and integrated.

This cable uses fluororesin as an insulator, so it has a low dielectric constant, and since it is made of foam, it has even better electrical properties.The drain wire is in contact with the shield tape, so the cable is terminally processed. It is easy to work with, and since the core is flat, wiring work is easy and has achieved the desired results.

[Problems that the invention aims to solve] However, when processing the terminals of this cable, a cutting machine is used to remove the jacket and the shield tape at the same time, but in order to further lower the dielectric constant, the insulation is removed. When a highly foamed insulator with a high degree of foaming is used, when the teeth of a cutting machine are inserted into the jacket, the soft foamed insulator deforms and absorbs the force of the cutting machine, causing the shield layer to open simultaneously with the jacket. There was a defect that could not be removed properly.

Furthermore, when the insulator is made to have a high degree of foaming of 50% or more, there is a drawback that the electrical properties change depending on the state of the bubbles due to the presence of air bubbles on the surface of the insulator, making the electrical characteristics unstable.

[Means for Solving the Problems] The purpose of the present invention is to eliminate the drawbacks of the prior art described above, and to provide a flat cable for electronic equipment that has good terminal processing workability and excellent crosstalk and electrical properties. It is about providing.

In other words, the gist is that an insulated conductor consisting of a central conductor, a highly foamed fluororesin insulator layer extruded and coated on its outer periphery, and a solid fluororesin insulator layer coated on its outer periphery; a drain wire attached vertically to at least one side of the conductor;
A plurality of cores each consisting of a press-wound shield tape layer provided on their outer peripheries and a fluororesin jacket coated on their outer peripheries by extrusion are arranged in parallel, and adjacent cores are spaced at least at predetermined intervals in the longitudinal direction. The press-wrapped shield tape is a laminate of aluminum and reinforcing polyester, and the polyester tape has independent holes uniformly provided in the vertical and horizontal directions of the tape. The flat cable is characterized in that the polyester tape surface is configured to face the jacket side.

[Function] In the above, silver-plated annealed copper wire is used as the center conductor and drain wire.

In other words, the flat cable of this invention uses fluororesin as the insulator and jacket.
Silver plating was applied to prevent the conductor from discoloring at the high temperatures during extrusion of the fluororesin.

The highly foamed fluororesin layer has a foaming degree of 50% or more,
Preferably 60% or more of PFA, FEP, or E-
TFE is provided by extrusion.

The solid fluororesin layer is provided by extrusion of PFA, FEP or E-TFE, and this solid fluororesin layer may be extruded and coated simultaneously with the highly expanded fluororesin layer, or may be provided separately. It is something.

Here, the solid fluororesin insulator layer must be provided sufficiently thinner than the foamed fluororesin insulator layer.

In other words, the solid fluororesin insulator layer is good for the purpose of stabilizing the electrical properties if it covers the surface of the foam insulator layer to make the surface smooth, and the thicker the solid fluororesin layer, the more the dielectric constant. This is not desirable because it increases

Although this thickness depends on the manufacturing technology, it is preferably 0.10 mm or less, particularly preferably 0.06 mm or less.

The drain wire may be provided on at least one side of the insulated conductor, and may be provided on both sides of the insulated conductor if necessary.

The press-wrap shield tape is preferably a laminate tape of aluminum and polyester, and is used with the aluminum side facing inside.

The aluminum tape used is approximately 9μ thick.

Polyester tape is for reinforcing aluminum tape, preferably 6μ or less, preferably 4μ or less,
The tape used has uniform, continuous, and independent holes drilled in both the vertical and horizontal directions, and its tensile strength has been reduced to a level that causes no problems in tape winding operations.

In other words, if the polyester tape is thick and does not have holes, it will be stronger and easier to handle during manufacturing, but if it is too strong, the shield tape will peel off at the same time as the jacket when processing the ends. This is because they are unable to do so.

Since the polyester tape has independent holes, its surface is uneven, and the frictional resistance against the jacket is large, allowing the shield layer to be peeled off at the same time as the jacket.

As a method of making holes in polyester tape,
Although it is possible to provide non-independent continuous holes, this is not preferable because the hole portion becomes a weak point.

According to experiments, when the polyester thickness is 25μ,
It was not possible to remove it at all, and when it was 12μ, only a portion of it could be removed.

On the other hand, those with uniform and continuous independent holes of 6μ or less to reduce the tensile strength
It is preferable in this application to use a polyester tape which is 100% removable and has uniform, continuous, independent holes with a thickness of 6 microns or less, preferably 4 microns.

Jackets include PFA, FEP, FTFE,
Fluororesin such as ECTFE is provided by extrusion coating.

Conventionally, extrusion coating of a fluororesin has generally been carried out by tube extrusion, and the cross-sectional shape is elliptical.

Therefore, when the cable cores are arranged in parallel, it is difficult to align the centers of the center conductor and the drain wire, resulting in the disadvantage that a collective connector cannot be used.

To solve this problem, the fluororesin jacket can be extruded and coated in a rectangular shape using a specially shaped die. This allows adjacent cores to be placed in line contact and the center conductor and drain wire to be centered. This makes it easier.

Further, as a method for heat-sealing the cores arranged in parallel, it is preferable that only the upper and lower surfaces of the cores be heat-sealed, and the contact portions between adjacent cores be non-sealed.

In other words, when fusing the core, only the top and bottom surfaces are heated to a temperature above the melting point of the jacket, but at this time, the volume of the jacket changes significantly (in particular, fluororesin has a tendency to expand in volume). (large), and it becomes impossible to obtain dimensional accuracy between the center conductors.To prevent this, it is preferable to heat-seal only the upper and lower surfaces.

[Embodiment of the invention] Next, an embodiment of the flat cable of the invention will be further described with reference to the accompanying drawings.

In FIG. 1, 1 is a central conductor, and a foamed insulator 2 and a solid insulator 3 are sequentially provided on the outer periphery of the central conductor, forming an insulated conductor.

Reference numeral 4 denotes a drain wire attached vertically to the insulated conductor, and a shield tape 5 is further provided around the outer periphery of the drain wire.

Reference numeral 6 denotes a jacket provided on the outer periphery of these cables, and constitutes a cable core.

Here, as the center conductor 1 and the drain wire 4, a silver-plated annealed copper wire with a diameter of 0.254 mm is used.

The foamed insulator 2 is made of PFA with a foaming degree of 60% or more, and is extruded to have an outer diameter of 0.57 mm.

E-TFE is used as the solid insulator 3,
Its thickness is about 0.06mm.

As the shield tape 5, a laminate tape of polyester and aluminum is used.
A tape 7 is used, which has a thickness of 9μ and polyester has a thickness of 4μ, and has uniform, continuous, and independent holes as shown in FIG.

Jacket 6 is extruded and coated with FEP.
The width is set to 1.27±0.07 and the thickness is set to 1.20±0.1.

A plurality of cable cores thus formed are integrated in parallel in parallel as shown in FIG. 2, and only the surfaces of adjacent cores are integrated by fusion.

According to the flat cable of this embodiment, which is constructed as described above, characteristics of characteristic impedance Z ₀ =56±5Ω and transmission speed Td=3.9±0.1 (nsec/m) are obtained.
Additionally, since the distance between the conductors was maintained at 1.27±0.07, it was possible to easily connect them all at once using pressure welding connectors.

[Effects of the invention] As explained above, according to the invention, it is possible to provide a cable for internal wiring of electronic devices that has excellent electrical characteristics and excellent terminal processing workability, and its practical value is extremely high. There is something big.

[Brief explanation of the drawing]

Fig. 1 is an explanatory cross-sectional view showing one embodiment of the core constituting the flat cable of the present invention, Fig. 2 is an explanatory cross-sectional view showing an embodiment of the flat cable of the present invention, and Fig. 3 is an explanatory cross-sectional view showing an embodiment of the core constituting the flat cable of the present invention. FIG. 2 is an explanatory diagram showing a cross section of an example of a polyester layer of a shielding tape used in FIG. 1: Conductor, 2: Highly foamed fluororesin insulator layer, 3:
Full fluororesin insulator layer, 4: Drain wire, 5:
Shield tape layer, 6: Fluororesin jacket layer,
7: Polyester tape.

Claims (1)

[Scope of utility model registration request] An insulated conductor consisting of a center conductor, a highly foamed fluororesin insulation layer coated on the outer periphery by extrusion, and a solid fluororesin insulation layer coated on the outer periphery; A plurality of cores are arranged in parallel, each consisting of drain wires, a press-wound shield tape layer provided around their outer peripheries, and a fluororesin jacket coated by extrusion on their outer peripheries, and the cores are arranged in parallel at least at predetermined intervals in the longitudinal direction. The above press-wrapped shield tape is made by heat-sealing only the surfaces of adjacent cores.
It is a laminate of aluminum and reinforcing polyester, and the polyester tape has independent holes uniformly provided in the vertical and horizontal directions of the tape, and is configured so that the polyester tape surface faces the jacket side. Features a flat cable.