JP2006093018A - Coaxial cable strand, coaxial cable, and multi-core coaxial cable - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coaxial cable and a multi-core coaxial cable provided with flexure resistant properties, twisting resistant properties, as well as durability, using copper foil thread for its center conductor. <P>SOLUTION: For a coaxial cable strand 1a, 1b, of which an outer periphery of the center conductors 2a, 2b made of a single-core wire or twisted wires is covered with an insulator 3, and outer conductors 4a, 4b are arranged on the outer periphery of the insulator, and the center conductor 2 is formed of copper foil thread. As the center thread of the copper foil thread, high tensile-strength fiber having a heat resistance such as that of aramid fiber is used. The coaxial cable is structured by covering the coaxial cable strand with a jacket made of an insulating material. Further, a plurality of coaxial cable strands are covered with a common jacket to make up a multi-core coaxial cable, or a plurality of coaxial cables are covered with a common jacket to make up a multi-core coaxial cable. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a coaxial cable used for signal transmission or the like at a bent portion or a twisted portion, and relates to a coaxial cable strand, a coaxial cable, and a multi-core coaxial cable.

  In recent years, with the spread of notebook computers, mobile phones, small video cameras, etc., in addition to the reduction in size and weight of these information communication devices, high-speed data transmission and higher density are required. In these communication devices, the liquid crystal display unit is usually configured to be foldable. For this reason, the electrical connection between the device main body unit and the display unit is a wiring structure involving rotation or twisting. It is said that. In general, it is necessary to suppress the occurrence of electromagnetic interference (EMI) between circuits due to electromagnetic waves radiated from signal lines.

  In order to cope with this, a flexible substrate (FPC) that can be bent for circuit mounting and wiring in an apparatus is used. However, in addition to the conventional folding type, recently, an opening / closing / twisting type device has appeared, and generally the wiring length of the FPC becomes long, and it is difficult to minimize the ground potential. For circuit wiring using FPC, a solid ground structure having a ground conductor layer as a ground conductor layer is known as a ground conductor layer for securing a low resistance ground conductor and EMI countermeasures. The bendability is poor at the bent part, and cracks may occur and break.

  For this reason, it is known that slits are made in the ground conductor portion of the rotating portion, or that signal conductors and ground conductors are alternately arranged in a staggered manner to reduce ground conductor performance and ensure flexibility. (For example, refer to Patent Document 1). However, if the number of solid ground conductors is reduced in order to improve flexibility, the resistance value of the ground conductor increases and the ground potential rises, and there is a problem that the impedance mismatch of signals and EMI characteristics deteriorate. The wiring method using the FPC has not provided a satisfactory effective solution.

It is also known to use a bending-resistant shielded cable at a portion where the bending of a robot or the like is repeatedly applied to the wiring of the rotating portion using the FPC (see, for example, Patent Document 2). In the bending-resistant shielded cable disclosed in Patent Document 2, the outer periphery of a cable core obtained by twisting a plurality of counter wires having a shield layer is pressed and wound, a shield layer is provided on the outer periphery, and the outermost layer is covered with a jacket. Configured. And it is supposed that both the shield layer of an electric wire and the shield layer of a cable core can be formed by horizontal winding or a braided structure using a copper foil thread. However, it is only disclosed as a bend-resistant shielded cable, and its usage is not clear.
Japanese Patent Laid-Open No. 2004-88020 Japanese Utility Model Publication No. 5-38712

  In contrast to the electrical wiring of rotating parts using FPC, recently, wiring is performed using a cable harness in which a plurality of ultra-thin coaxial cables are bundled in a part that involves opening / closing and twisting of a folding device such as a mobile phone. Is being considered. In the wiring system using the cable harness made of this ultrafine coaxial cable, the use of the coaxial cable is considered to have no problem with respect to impedance matching and EMI. However, a copper alloy stranded wire is used to give a certain degree of tensile strength to the central conductor of the coaxial cable used, but it is fragile to twist and bend, and has a difficulty in twisting characteristics especially for mobile phone applications. As a cause of this, there is a problem that a foreign matter mixed portion, a metal dispersion defective portion, or the like exists in the conductor, and twisting breakage occurs from that point.

  The present invention has been made in view of the above-described circumstances, and by using a copper foil thread as a central conductor of a coaxial cable, a coaxial cable strand and a coaxial cable having performance ensuring and durability against bending / twisting, and The issue is to provide a multi-core cable.

  A coaxial cable strand according to the present invention is a coaxial cable strand in which the outer periphery of a central conductor made of a single core wire or a stranded wire is covered with an insulator, and an outer conductor is disposed on the outer periphery of the insulator, Form with copper foil thread. As the center yarn of the copper foil yarn, it is preferable to use a heat resistant high tensile strength fiber such as an aramid fiber.

  A coaxial cable according to the present invention is configured by covering the above-described coaxial cable strand with an outer jacket made of an insulating material. Further, a plurality of coaxial cable strands can be covered with a common jacket to form a multi-core coaxial cable, or a plurality of coaxial cables can be covered with a common jacket to form a multi-core coaxial cable. A plurality of coaxial cable strands or coaxial cables may be flat multi-core coaxial cables arranged in parallel.

  As in the present invention, by using a copper foil thread as the central conductor, a coaxial cable having a sufficient performance and durability against bending and twisting can be obtained, and the cable is excellent in flexibility and has a long life and reliability. A harness can be produced.

  Embodiments of the present invention will be described with reference to the drawings. 1A and 1B are diagrams showing an example of a coaxial cable strand according to the present invention, FIG. 1C is a diagram for explaining a configuration of a copper foil thread, and FIG. 1D is a coaxial cable. It is a figure which shows the center conductor of this. In the figure, 1a and 1b are coaxial cable strands, 2a is a central conductor (single core wire), 2b is a central conductor (stranded wire), 3 is an insulator, 4a is an external conductor (ribbon conductor), and 4b is an external conductor ( (Circle line), 6 is a copper foil thread, 7 is a high tensile strength fiber, and 8 is a copper foil tape.

  In the coaxial cable strands 1a and 1b according to the present invention, the outer periphery of a central conductor 2a made of a single core wire or a central conductor 2b made of a stranded wire is covered with an insulator 3, and an outer conductor 4a or 4b is coaxially arranged on the outer side. Configured. As will be described later, the coaxial cable strands 1a and 1b are formed into a coaxial cable by covering the outer sides of the outer conductors 4a and 4b with a jacket, and are formed into a multi-core cable by covering a plurality of cables with a common jacket. The

  In the coaxial cable strand 1a shown in FIG. 1A, for example, a single core wire is used for the center conductor 2a, the outer conductor 4a is a flat ribbon conductor on the outer periphery of the insulator 3, and a predetermined helical pitch (for example, winding In this example, the film is uniformly wound at an angle of 45 degrees or more. In the coaxial cable strand 1b shown in FIG. 1B, for example, a stranded wire is used for the center conductor 2b, a round copper alloy wire is used for the outer conductor 4b on the outer periphery of the insulator 3, and a horizontal winding or a braided structure is used. This is an example. The central conductor of the coaxial cable strand 1a shown in FIG. 1 (A) may be a stranded wire, and the central conductor of the coaxial cable strand 1b shown in FIG. 1 (B) may be a single core wire.

  In the present invention, the copper foil yarn 6 is used as a single core wire or a stranded wire as the central conductor of the coaxial cable strands 1a and 1b having the above-described shape. The copper foil thread 6 has, for example, a shape as shown in FIG. 1C, and is generally used for an earphone, a headphone, a curl cord of a telephone, etc., and has a bending strength, flexibility and lightness. It is known as a special conductor. Further, as disclosed in Patent Document 2, it is also widely used as a shield conductor for cables.

  The copper foil yarn 6 is generally formed by wrapping a flat wire copper foil tape 8 produced by rolling a round wire around a polyester-based high strength fiber 7. In addition, it may be a multi-copper foil thread in which 2 to 4 copper foil tapes are wound in layers. As the copper foil material, tin alloy copper or ordinary copper is used, and copper foil yarn 6 having an outer diameter of about 0.1 mm is widely used. In this invention, this copper foil thread | yarn 6 is used as a center conductor with a single core wire, or as shown in FIG.1 (D), a plurality (for example, 7 pieces) are twisted as the center conductor 2b. use. By twisting a plurality of single-core copper foil yarns 6, the mechanical strength can be increased and the overall resistance value can be lowered.

  When the copper foil thread 6 is used for the central conductors 2a and 2b of the coaxial cable strands 1a and 1b, the copper foil thread 6 is passed through the cross head to be covered with the insulator 3. When the cross head passes, the high tensile strength fiber 7 that is the center yarn of the copper foil yarn 6 is heated, and the polyester yarn may not be able to withstand sufficiently. Therefore, as the high tensile strength fiber 7 used in the present invention, it is preferable to use an aramid fiber excellent in high tensile strength and having heat resistance.

  FIG. 2 is a diagram for explaining the outline of the coaxial cable according to the present invention. 2A and 2B show a cross section of the coaxial cable, and FIGS. 2C and 2D show a state where the components are partially exposed. 2A shows an example in which a single core wire is used for the center conductor, and FIG. 2B shows an example in which a stranded wire is used for the center conductor. In the figure, reference numerals 10a and 10b denote coaxial cables, 11 denotes a jacket, and the other reference numerals are the same as those used in FIG.

  As the coaxial cable 10a shown in FIG. 2A, for example, the outer periphery of the coaxial cable strand 1a shown in FIG. As described with reference to FIG. 1A, the center conductor 2a uses a single-core copper foil thread, and the outside is covered with an insulator 3, and a flat ribbon conductor is formed on the outside with a predetermined helical pitch (for example, The outer conductor 4a is uniformly wound at a winding angle of 45 degrees or more. The flat ribbon conductor may be formed of a good conductive material such as copper or aluminum, and a round wire rolled flat. The ribbon conductor may be wound in close contact or wrapping so that no gap is generated, or may be wound in two layers with the winding direction opposite.

  As the coaxial cable 10b shown in FIG. 2B, for example, the outer periphery of the coaxial cable strand 1b shown in FIG. As described with reference to FIG. 1B, the central conductor 2b uses a stranded wire obtained by twisting a plurality of copper foil yarns, covers the outside with an insulator 3, and is formed of copper or alloy copper on the outside. A plurality of round wires are wound in a horizontal winding or a braided structure to form the outer conductor 4b.

  As described above, the coaxial cable strand or the coaxial cable formed by using the copper foil thread for the center conductor is more flexible than the conventional center conductor using the copper alloy wire, and is also bent and twisted. Strong and long life. Further, by using an aramid fiber having high heat resistance as the high tensile strength fiber of the copper foil yarn, it is possible to maintain high strength and to form the insulator as a fluororesin that requires high-temperature extrusion.

  FIG. 3 is a diagram showing an example in which a multi-core coaxial cable is formed using a plurality of coaxial cable strands shown in FIG. 1 or a plurality of coaxial cables shown in FIG. A multi-core coaxial cable 12a shown in FIG. 3 (A) uses a single core wire for the center conductor 2a, and a plurality of coaxial cable strands 1a or 1b in FIG. This is an example. In this example, the outer conductors 4a or 4b of the coaxial cable strands 1a or 1b are in contact with each other and are electrically connected in common, so that the resistance can be reduced and the shield potential difference can be kept small.

  The multi-core coaxial cable 12b shown in FIG. 3 (B) is an example in which a stranded wire is used for the center conductor 2b and a plurality of coaxial cables 10a or 10b in FIG. It is. In this example, each of the coaxial cables 10a or 10b is protected by the jacket 11 and can be easily branched in a single core. Will be better. In addition, the twist performance in a rotation part can be improved by gathering a some coaxial cable circularly like FIG. 3 (A) and FIG. 3 (B).

  FIG. 3C shows a multi-core coaxial cable 14a in which a single core wire is used for the center conductor 2a, and a plurality of the coaxial cable strands 1a or 1b in FIG. FIG. 3D shows a multi-core coaxial in which a twisted wire is used for the central conductor 2b, and a plurality of the coaxial cables 10a or 10b in FIG. An example of the cable 14b is shown. In the configurations of FIGS. 3C and 3D, the common jacket 15 may be configured to cover the upper and lower surfaces of the coaxial cable by adhesive bonding.

  3 (C) and 3 (D) show the flat shape of the multi-core coaxial cable shown in FIGS. 3 (A) and 3 (B). The advantages of each are shown in FIGS. 3 (A) and 3 (B). This is similar to the case of 3 (B). By using a flat shape, it can be used in the same manner as FPC, and is particularly suitable for wiring along a flat surface and can improve bending performance. 3A to 3D, each coaxial cable is shielded by the external conductor 4a or 4b, and impedance matching and EMI characteristics can be ensured.

  FIG. 4 is a diagram illustrating an example in which an electrical connection terminal portion is formed on the various multi-core coaxial cables of FIG. As shown in FIG. 4 (A), the electrical connection terminal section is a connection terminal 16a in which ends of the coaxial cables are arranged in a form that facilitates electrical connection, or an electrical connector or the like as shown in FIG. 4 (B). It can be formed by the connection terminal 16b to which the connection means is connected. The electrical connection is usually made by a jack connector and a plug connector in which a large number of contacts are arranged in a row at a high density. For this reason, the cable ends of the multi-core coaxial cables 12a, 12b or 14a, 14b are arranged in a parallel line and arranged in a flat shape at a predetermined pitch in advance, or an electrical connector is connected to the multi-core with an electrical connector. It is preferably provided as a coaxial cable.

It is a figure explaining the coaxial cable strand by this invention. It is a figure explaining the coaxial cable by this invention. It is a figure explaining the multi-core coaxial cable by this invention. It is a figure which shows the multi-core coaxial cable provided with the electrical connection terminal by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1a, 1b ... Coaxial cable strand, 2a ... Center conductor (single core wire), 2b ... Center conductor (stranded wire), 3 ... Insulator, 4a ... External conductor (ribbon conductor), 4b ... External conductor (round wire) , 6 ... Copper foil thread, 7 ... High tensile fiber, 8 ... Copper foil tape, 10a, 10b ... Coaxial cable, 11 ... Outer sheath, 12a, 12b, 14a, 14b ... Multi-core coaxial cable, 13, 15 ... Common outside Cover, 16a, 16b ... connection terminal.

Claims (9)

  A coaxial cable element in which an outer periphery of a center conductor is covered with an insulator, and an outer conductor is disposed on the outer periphery of the insulator, wherein the center conductor is formed of a copper foil thread. line.   The coaxial cable strand according to claim 1, wherein a heat-resistant high tensile strength fiber is used for a center yarn of the copper foil yarn.   The coaxial cable strand according to claim 2, wherein the high tensile strength fiber is an aramid fiber.   The coaxial cable strand according to any one of claims 1 to 3, wherein the central conductor is formed of a stranded wire obtained by twisting a plurality of copper foil yarns.   A coaxial cable, wherein the coaxial cable strand according to any one of claims 1 to 4 is covered with an outer jacket made of an insulating material.   A multi-core coaxial cable, wherein a plurality of the coaxial cable strands according to any one of claims 1 to 4 are covered with a common jacket made of an insulating material.   A multi-core coaxial cable, wherein a plurality of the coaxial cables according to claim 5 are covered with a common jacket made of an insulating material.   The multi-core coaxial cable according to claim 6 or 7, wherein a plurality of the coaxial cable strands or coaxial cables are arranged in a parallel line.   The multi-core coaxial cable according to any one of claims 6 to 8, wherein an electrical connection terminal is formed on at least one end.

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