JP2008181755A - Coaxial cable and multi-core cable - Google Patents

Abstract

The present invention provides a coaxial cable having a coating that is reduced in hardness and thickness, has no variation in electric resistance, and can be easily peeled off during terminal processing.
In a coaxial cable, an insulating layer is first coated on a central conductor, an external conductor is provided outside the insulating layer, and a resin tape is wound around the external conductor to form a jacket. The resin tape 10 has a resin layer 11 and an adhesive layer 13. The width L of the adhesive layer 13 is narrower than the width W of the resin layer 11. It is preferable that the resin tape 10 is overlapped and wound around at least a portion including the adhesive layer 13.
[Selection] Figure 2

Description

  The present invention relates to a coaxial cable and a multi-core cable, and more particularly to an ultra-fine diameter coaxial cable and a multi-core cable in which a plurality of coaxial cables are assembled.

  In recent years, miniaturization and high performance have been demanded in all devices such as medical probes such as endoscopes and communication devices such as mobile phones, and in response, insulated wires used as cable harnesses or inside devices And coaxial cables are also required to have very thin outer diameters. For example, for coaxial cables, very thin ultra-fine coaxial cables having an outer diameter of 0.25 mm or 0.16 mm are manufactured, and multi-core cables formed by twisting, for example, a plurality of such ultra-fine coaxial cables are put to practical use. ing.

  As shown in FIG. 1 (B), the micro coaxial cable 5 forms a core by forming an insulating layer 62 on the outer periphery of the center conductor 63, and a plurality of ultra fine outer conductors are wound horizontally on the outer periphery of the core. The shield layer 61 is formed, and the jacket (outer jacket) is coated on the outer periphery of the shield layer 61. The shield layer 61 may be formed by braiding or metal tape other than horizontal winding.

  For example, as described in Patent Document 1, the jacket is formed by winding a plastic tape such as polyester by overlapping winding. A typical example of the polyester tape is a polyethylene terephthalate (PET) tape. When a resin tape such as a polyester tape is lap-wrapped, an adhesive layer is provided so that the wound tape cannot be unwound and the tape is bonded together.

  However, when the winding is performed with the adhesive layer on the inside, the shield layer 61 and the resin tape are bonded to each other, so that it is difficult to expose the shield layer 61 during terminal processing. On the other hand, if the adhesive layer is placed on the outer side and the wrap-around is performed, the cables are caught by each other and cannot be fed out when the coaxial cable is wound up.

  Therefore, as shown in FIG. 1B, in the conventional micro coaxial cable 5, a non-adhesive (plain color) resin tape 60 is inserted between the shield layer 61 and the resin tape 50 with adhesive. Yes.

More specifically, as illustrated in FIG. 2B, in the resin tape with adhesive 50, for example, an adhesive layer 53 is attached to one whole surface of the PET tape 51 with a pigment layer 52 interposed therebetween. Then, as shown in FIG. 3 (B), an adhesiveless resin tape 60 is first lap-wrapped on the shield layer 61, and the adhesive-attached resin tape 50 is further lap-wrapped with the adhesive layer 53 inside. Is done.
JP 2006-32073 A

  However, in the conventional micro coaxial cable, since two resin tapes are wound in layers and heat-bonded, the resin tape is tightly wound, the adhesion to the external conductor is strong, and the difficulty of exposing the external conductor during terminal processing remains. Remain.

  Moreover, since the conventional micro coaxial cable is wound with resin tape as a result, it tends to be thick and hard. Furthermore, as shown in FIG. 4 (B), since two resin tapes 50 and 60 are overlapped and wound, a part that overlaps only two parts (part indicated by a dashed-dotted ellipse), and three or four There are overlapping parts (parts indicated by dashed ellipses). As described above, since the conventional micro coaxial cable has a variation in the overlap, the pressure resistance characteristic provided to the resin tape such as a PET tape also varies.

  The present invention has been made in view of the circumstances as described above. A coaxial cable having a coating that reduces hardness and thickness, has no variation in electric resistance, and can be easily peeled off during terminal processing, and the coaxial cable. An object is to provide a multi-core cable in which a plurality of sets are assembled.

A coaxial cable according to the present invention is a coaxial cable in which a central conductor is covered with an insulating layer, an outer conductor is provided outside the insulating layer, and a resin tape is wound around the outer periphery of the coaxial cable. It has an adhesive layer, and the width of the adhesive layer is narrower than the width of the resin layer.
The multi-core cable according to the present invention is characterized in that a plurality of the coaxial cables described above are assembled into a multi-core cable.

  According to the coaxial cable of the present invention, it is possible to reduce the hardness and thickness, to provide a coating that can be easily peeled off even during terminal processing without variation in electric resistance. Thereby, a thin and soft multi-core cable can be provided.

  1 is a cross-sectional view showing an example of a coaxial cable using a resin tape as a jacket, FIG. 2 is a diagram showing an example of a layer structure of the resin tape in the coaxial cable of FIG. 1, and FIG. 3 is a resin of FIG. FIG. 4 is a schematic cross-sectional view illustrating an example of a layer structure when a resin tape is wound by the winding method of FIG. 3. 1 to 4, each figure (A) shows a coaxial cable according to the present invention, and each figure (B) shows a conventional coaxial cable for comparison with each figure (A).

  As illustrated in FIG. 1A, the ultra-thin coaxial cable 1 according to the present invention covers the outer periphery of the center conductor 23 with an insulating layer 22, and a shield layer 21 made of an external conductor is provided outside the insulating layer 22. Further, the resin tape 10 is wound as an outer cover.

  In such a micro coaxial cable 1, first, the center conductor 23 is covered with an insulating layer 22 such as fluororesin, foamed fluororesin, solid polyethylene (PE), foamed PE or the like to form an insulating wire serving as a core. The insulated wire (insulated wire) is not limited to the single core as shown in FIG. 1A as the central conductor 23, and may be a stranded wire obtained by twisting a plurality of thin conductors. . In addition to forming the insulating layer by extrusion of fluororesin or polyethylene, other structures such as polyester tape winding may be adopted as long as the central conductor 23 and the outer conductor can be insulated.

  Then, the shield layer 21 is formed on the insulated wire (core) by winding a plurality of ultrafine outer conductors horizontally. A strand such as a tin-plated alloy wire is used as the outer conductor, and is wound spirally on the insulator. The shield layer 21 may be formed by lightly compressing a plurality of horizontally wound ultrafine conductors and using a flat ultrafine conductor, or may have a braided structure. Or you may form with a copper foil thread | yarn or a metal tape.

  And in the micro coaxial cable 1 which concerns on this invention, as shown to FIG. 1 (A), the resin tape 10 is wound on the shield layer 21 as a restraining volume. The resin tape 10 serves as a jacket (outer jacket) for the coaxial cable 1.

  The resin tape 10 used in the present invention is a tape such as a polyester tape partially having an adhesive. More specifically, as shown in FIG. 2A, in the resin tape 10 with an adhesive, for example, the pigment layer 12 is formed on one entire surface of the PET tape 11, and the adhesive layer 13 is further formed on a part thereof. It is pasted. Here, the pigment layer 12 may not be provided and may remain transparent. A dye may be added to the adhesive layer 13.

  Thus, the resin tape 10 has the resin layer such as the PET tape 11 and the adhesive layer 13, and the width L of the adhesive layer 13 is narrower than the width W of the resin layer such as the PET tape 11. . That is, the adhesive layer 13 exists only in a part of the resin layer (PET tape 11 or the like) in the width direction, and the adhesive layer 13 and the region where the adhesive layer 13 is not formed on the resin layer. The application region 14 exists. Here, a PET tape with a partial adhesive is illustrated as the resin tape 10, but other materials such as polyethylene naphthalate (PEN) and polypropylene (PP) are used as the resin layer in addition to the PET tape 11. May be.

  As the PET tape 11, for example, a tape having a width W of about 0.9 mm to 4 mm may be adopted. For example, when the width W of the resin layer is about 2.0 mm, the width L of the adhesive layer 13 may be about 0.7 mm. Further, the thickness T of the PET tape 11 is about 1.5-6 μm (such as 4.0 μm), the thickness t of the pigment layer 12 is about 1.0 μm, and the thickness d of the adhesive layer 13 is about 1.5 μm. Good.

  When the resin tape 10 is overlapped with the shield layer 21 as a winding, as shown in FIG. 3A, the inner adhesive portion by the adhesive layer 13 is PET tape so that the wound tape cannot be unwound. 11, and only the inner unbonded portion by the adhesive uncoated region 14 can be in contact with the shield layer 21.

Thus, the resin tape 10 used in the present invention can be wound without the adhesive layer 13 being in contact with the shield layer 21 by controlling the overlap at the time of winding. That is, it is possible to wrap and overlap the opposite surface of the PET tape 11 at a portion including at least the adhesive layer 13. In other words, the resin tape 10 may be wound with the width L _D (see FIG. 4A) equal to or greater than the width L of the adhesive layer 13 being overlapped.

  Here, in FIG. 3A, the description has been made on the assumption that the adhesive layer 13 and the adhesive non-applied region 14 are wound on the side in contact with the shield layer 21, but when the coaxial cable 1 is wound up. In order to prevent the cables from sticking to each other, the adhesive layer 13 and the adhesive-unapplied region 14 can be directed and wound on the outside.

  After the resin tape 10 is wound around the shield layer 21, it is allowed to stand at a high temperature for several hours in the constant temperature layer, or fusion is performed through a high temperature heating furnace. As the adhesive layer 13, a material that melts at 80 ° C. or higher is adopted. Usually, after the resin tape 10 is wound, the resin tape 10 is bonded to each other by placing it in a constant temperature bath at 90 ° C. or 100 ° C. for 4 hours. it can.

  As shown in FIGS. 3 (B) and 1 (B), the micro coaxial cable 1 generated after the fusion is completed is wound without the adhesive layer 13 being in contact with the shield layer 21. Conventionally, two PET tapes that have been overlaid can be reduced by one as shown in FIGS. 3 (A) and 1 (A). As described above, the micro coaxial cable 1 of the present invention can be made thinner than the conventional one, and the flexibility can be increased.

  Further, as shown in a partial cross-section in FIG. 4A, the finished micro coaxial cable 1 can be wound in a single sheet, thereby reducing variations in overlap of the resin tape 10 and improving the pressure resistance characteristics. The variation is also reduced. That is, in the present invention, since the resin tape 10 is overlapped with only one sheet, the overlapping portion is unified into three sheets (2 sheets depending on the winding method) as shown by the dashed ellipse in FIG. can do. Further, the coaxial cable 1 has less appearance irregularities, so that the appearance is clean.

  Further, in the micro coaxial cable 1, since only one sheet of the resin tape 10 is wound, the tightening can be reduced and the resin tape 10 is easily stripped. Moreover, even when the adhesive layer 13 and the adhesive non-applied region 14 are overwrapped toward the side in contact with the shield layer 21 or overwrapped outward, the adhesive of the resin tape 10 is processed at the time of terminal processing. The layer 13 does not touch the shield layer 21 to make it difficult to strip the tape.

  As described above, the coaxial cable according to the present invention has been described. However, the present invention provides a multicore cable in which a plurality of the coaxial cables are provided and connected by a connecting material, stored in a slot, or a plurality of coaxial cables are covered with a tube. A form as a cable (also referred to as a coaxial multi-core cable) may be employed.

  FIG. 5 is a cross-sectional view showing an example of a multi-core cable formed by assembling a plurality of coaxial cables of FIG. The multi-core cable 3 illustrated in FIG. 5 is a structure in which a plurality of coaxial cables 1 as described above are assembled to form a multi-core. The multi-core cable 3 includes four coaxial cables 1 and eight insulated wires (or spacers) 31 and the outer side thereof is covered with a jacket 32. Various structures such as providing a separate shield layer inside the outer jacket 32 can be applied.

It is sectional drawing which shows an example of the coaxial cable which used the resin tape as a jacket. It is a figure which shows an example of the layer structure of the resin tape in the coaxial cable of FIG. It is a figure for demonstrating an example of how to wind the resin tape of FIG. It is a schematic sectional drawing which shows an example of a layer structure when a resin tape is wound with the winding method of FIG. It is sectional drawing which shows an example of the multi-core cable formed by collecting a plurality of coaxial cables of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Coaxial cable, 3 ... Multi-core cable, 10 ... Resin tape, 11 ... PET tape, 12 ... Pigment layer, 13 ... Adhesive layer, 14 ... Adhesive non-application area | region, 21 ... Shield layer, 22 ... Insulating layer, 23 ... center conductor, 31 ... insulated wire, 32 ... jacket.

Claims (3)

  A coaxial cable covering the central conductor with an insulating layer, providing an outer conductor outside the insulating layer, and wrapping with a resin tape, the resin tape having a resin layer and an adhesive layer; A coaxial cable characterized in that the width of the adhesive layer is narrower than the width of the resin layer.   The coaxial cable according to claim 1, wherein the resin tape is overlapped and wound at least at a portion including the adhesive layer.   A multi-core cable in which a plurality of coaxial cables according to claim 1 or 2 are assembled to form a multi-core cable.

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