JPS6021854Y2 - shielded cable - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to improvements in shielded cables.

2. Description of the Related Art In recent years, shielded cables having a structure in which a cable core is divided into eastbound and hundredbound lines using shielding tape have been used as cables for transmitting high-frequency signals such as television and telephone signals, or digital signals such as PCM.

Above all, in order to achieve sufficient shielding, at least one of the eastbound line core 10 and the 6th line line core 20 (in the figure, the eastbound line A so-called D-type shielded cable is used in which the core (core) is completely surrounded by shielding tape 30.

40 is the outer shielding layer and 50 is the protective sheath.

However, this D-type shielded cable had the following problems and was difficult to manufacture.

That is, the shielding tape 30 is vertically interposed between the cable cores 10 and 20, then formed to surround the cable core 10, and finally the tape ends are overlapped.

As shown in FIG. 2, the overlapping method is generally carried out by pressing the inner end of the shielding tape with a presser 40.

On the other hand, in order to impart flexibility to the cable, the entire cable is twisted at the same time as the tape is formed.

In addition, the position of the seam of the shielding tape 30 constantly moves from side to side due to the twisting of the cable, and the presser 40 cannot follow this movement. Because the tape is held down, it tends to shift in one direction, so the inner and outer ends of the tape may be swapped, which is a problem in cable manufacturing.

The present invention has been devised in view of the above, and provides a new shielded cable that has the same performance as the D-type shielded cable, is easy to manufacture, and has additional benefits. At least one of the east line core and the 6th line core is surrounded by a first shielding tape in a C-shaped cross section to separate both cores, and the first A second shielding tape is vertically interposed between the shielding tape and the wire core so as to span between the open ends of the first shielding tape.

The present invention will be explained below based on the drawings.

FIG. 3 is a sectional view of an embodiment of the present invention.

In the figure, 1 is the line core for the east side line, 2 is the line core for the 6-row line, and 3 is the first shielding tape that surrounds the line core for the east side line in a substantially C-shaped cross section, and the end portion thereof There is an opening 4 between 31 and 32.

A second shielding tape 5 is interposed vertically between the first shielding tape 3 and the wire core 1 so as to span between the open ends 31 and 32 of the first shielding tape.

The length l of the overlapping portion of both shielding tapes depends on the cable size, but may be about 5 to 40 rrvn.

Further, 6 is an external shielding layer surrounding the east line line core 1 wrapped with the first shielding tape 3 and the 6th line line core 2;
7 is a protective sheath.

In order to insert the second shielding tape vertically, as shown in FIG. What is necessary is to insert a presser 8 wider than the shielding tape and press it against the wire core 1 side with the presser 8.

A simple metal tape may be used as the second shielding tape, but if the thickness of the tape exceeds 100 μm, there is a risk of damaging the core insulation at the tape end, so use a laminate tape with at least the tape end covered with plastic. It's good to do that.

If you use a metal thin film composite tape with a metal layer of several micrometers to several tens of micrometers and lined with paper or plastic tape, the tape itself is extremely flexible, so it is possible to insulate the core at the end of the metal layer. It is preferable and does not cause any damage.

Generally, in the case of a D-type shielded cable, the inner end of the shielding tape comes into contact with the core wire, and there is a risk that this end may damage the core insulation.To prevent this, the tape end is covered with plastic. Although an edge-treated laminate tape is used, in the present invention, by interposing the second shielding tape, there is no need to worry about this, and the first shielding tape 3 can also be made of a simple metal. .

In addition, if the metal surface of the second shielding tape 5 is arranged so as to be in contact with the first shielding tape 3, the metal surfaces of both shielding tapes will be in contact with each other, so laminated as a shielding tape. It is possible to obtain a cable with superior crosstalk characteristics compared to a D-type shielded cable, in which metals cannot be brought into contact with each other at the overlapping portion of the tapes because tape must be used.

Of course, in this case, a single-sided laminated tape may be used as the first shielding tape 3, with the inner surface being a metal surface.

Since the shielded cable according to the present invention has the above-mentioned configuration, it has the following effects.

1 Since the ends of the first shielding tape 3 are open, it is possible to stably manufacture the cable without having to worry about replacing the tape ends, as is the case with D-type shielded cables. .

Moreover, the cable performance is almost the same as that of the D-type shielded cable.

2 In the case of a D-type shielded cable, there is a risk that the inner tape end may damage the insulation of the cable core, so it is necessary to use an edge-treated laminated tape. Since the shielding tape has a trauma-preventing effect, it is also possible to use a mere metal tape as the first shielding tape, thus providing a cable that is much cheaper than a D-type shielded cable.

3 Furthermore, as the first shielding tape, a tape with an exposed metal surface on at least one side is used, and is arranged with the metal surface facing inward, and as the second shielding tape, a tape with the metal surface exposed on one side is used. If the metal surfaces of the first and second shielding tapes are brought into contact with each other by interposing them with the metal surfaces facing outward, the metal surfaces can be brought into contact with each other at the overlapped portion of the shielding tapes. It is possible to obtain a cable with superior crosstalk characteristics compared to a D-type shielded cable that cannot.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a conventional D-type shielded cable, and FIG. 2 is an explanatory diagram showing a method of overlapping the ends of the shielding tape when manufacturing the cable of FIG. 1. Fig. 3 is a sectional view of one embodiment of the shielded cable according to the present invention, and Fig. 4 is an explanatory diagram showing a method of interposing a second shielding tape when manufacturing the cable shown in Fig. 3. It is. In Fig. 3, 1... East line line core, 2...
...6-line line core, 3...first shielding tape, 5...second shielding tape, in Figure 4, end...presser Ingredients.

Claims (1)

[Scope of utility model registration request] The core of at least one of the east line core and the 6th line core is surrounded by a first shielding tape in a substantially C-shaped cross section to divide both cores, and the first shielding tape and the wire A shielded cable characterized in that a second shielding tape is longitudinally interposed between the cores so as to span between the open ends of the first shielding tape.