WO1999052116A1

WO1999052116A1 - Coaxial cable, multicore cable, and electronics using them

Info

Publication number: WO1999052116A1
Application number: PCT/JP1999/001744
Authority: WO
Inventors: Kiyonori Yokoi; Akinori Mori; Seiji Endo; Akira Yamamoto
Original assignee: Sumitomo Electric Industries, Ltd.
Priority date: 1998-04-06
Filing date: 1999-04-01
Publication date: 1999-10-14
Also published as: KR100613954B1; TW424241B; JPH11297132A; EP0987720A4; EP0987720A1; DE69923740D1; EP0987720B1; KR20010013227A; DE69923740T2

Abstract

A coaxial cable capable of facilitating an external conductor removing work for terminal treatment, providing an excellent insulation characteristics, and reducing noise even if it is bent or rotated, wherein one or more pieces of coaxial strands (1) having an external conductor which are formed by spirally winding a ribbon-shaped conductor having smoothly cornered generally rectangular cross section, at an angle of 45° or higher, around the periphery of an insulating body are used so as to form a coaxial cable, and the coaxial cables are disposed at those positions where they are subject to mechanical rotation and bending so as to form electronics.

Description

Description Coaxial cable, multi-core cable and electronic equipment using the same

The present invention relates to a single-core coaxial element wire, a coaxial cable or a multi-core coaxial cable used for connecting a liquid crystal display inside a notebook computer or a sensor cable of a medical ultrasonic diagnostic apparatus, and an electronic apparatus using the same. About. Background art

Conventionally, coaxial cables in which a sheath is applied to a coaxial element wire composed of a center conductor, an insulator, and an outer conductor have been used. Such coaxial cables include a single-core cable in which a single coaxial cable is covered, a multi-core cable in which a plurality of single-core cables are provided with a common cover, and a plurality of coaxial cables. There is a multi-core cable for applying a common jacket. As a method of arranging coaxial wires or single-core cables in a multi-core cable, there is a layered multi-core cable in which coaxial wires or single-core cables are mutually twisted with a flat multi-core cable arranged on a plane. Such a single-core or multi-core coaxial cable may be a combination of cables of the same type or a composite cable combining other types of communication lines and power lines.

In a conventional coaxial cable, a metal tape or a laminated tape obtained by laminating a metal tape and an insulating film such as polyester is generally used as an outer conductor (shield). For example, braided metal tapes such as those disclosed in Japanese Utility Model Laid-Open No. 2-74772 and Japanese Patent Laid-Open No. 2-77728 are known. When the outer conductor is a metal tape braid, there is an advantage that it does not vary. On the other hand, there is a disadvantage that it takes time and effort to remove the external conductor for terminal treatment.

FIG. 4 is a side view showing a conventional coaxial cable using a braided metal tape. In FIG. 4, 11 is a center conductor, 12 is an insulator, 13 is an outer conductor braided with metal tape, and 14 is a jacket. As such a metal tape, a slit of a wide metal tape is usually used, but a cut surface at the time of slitting the metal tape is used. On the contrary, sharp edges such as burrs remain, and this portion may damage the insulator, or the voltage may be concentrated at this point, and the withstand voltage may decrease. In particular, this problem becomes serious in the case of a thin coaxial cable having a thin insulation thickness of 0.15 mm or less.

In addition, the conventional coaxial cable can be used to move the sensor wiring for electronic devices, especially for the medical sensor cable, where the cable moves whenever the rotating part, which is the connection between the monitor and the main unit of a notebook computer, or the medical treatment site is changed. When the coaxial cable is moved, the static noise is generated due to friction between the insulator and the outer conductor when the coaxial cable moves. Disclosure of the invention

The present invention has been obtained as a result of various studies on the above problems, and can be applied to the coaxial cables of the above various forms. The present inventors have used, as an external conductor, a ripon-shaped conductor obtained by rolling and flattening a copper or copper alloy round wire, and spirally winding the ripon-shaped conductor on an insulator to form an outer conductor. By configuring, it is possible to obtain a coaxial element wire and a coaxial cable having flexibility, small generation of noise when mechanical movement is performed, and excellent in mechanical durability and having a small outer diameter. This led to the completion of the present invention.

The present invention firstly provides a coaxial strand comprising a center conductor, an insulator and an outer conductor, wherein the insulator has a thickness of 0.15 mm or less and a copper or copper alloy round wire is rolled as the outer conductor. A coaxial strand characterized by using a ribbon-shaped conductor that has been flattened, and the ribbon-shaped conductor is spirally wound around an insulator.

Second, it is a coaxial wire consisting of a center conductor, an insulator, and an outer conductor, and the insulator is provided in contact with and around the core conductor, and the thickness of the insulator is 0.03 mm at the smallest part. The outer conductor is 0.15 mm or less, and the outer conductor is formed by spirally winding one or more ripon-shaped conductors with a smooth cross section at four corners, with one long side facing the insulator. And a winding angle of the ripon-shaped conductor with respect to the axis of the coaxial wire is 45 degrees or more. Here, when the center conductor is a fire wire of a plurality of conductor wires, the thickness of the insulator is obtained as the thickness of the smallest part by measuring the thickness of the insulator in the circumferential direction. Here, the ribbon-shaped conductor is made of a metal containing copper, It is wound around the insulator with a tension of 30% or more of the tensile breaking tension of the conductor.

Also, a single core coaxial cable may be provided by coating the single coaxial strand described above with a jacket.

Also, a multi-core cable in which a plurality of the above-described coaxial wires are gathered and provided with a common jacket may be used. Further, the single core coaxial cable may be provided with a common jacket to form a multicore cable.

Further, the electronic device is characterized in that the coaxial element wire, the coaxial cable or the multi-core cable is arranged at a position where the electronic device is mechanically turned or bent.

The substantially rectangular ripon-shaped conductor having a smooth cross section at four corners can be easily manufactured at low cost by rolling and flattening a copper or copper alloy round wire. In the present invention, since the ripon-shaped conductor does not have a sharp edge on the outer periphery of the cross section, there is no problem of damage to the insulator or voltage concentration when wound as an external conductor, and such a substantially rectangular ripon. The conductor has high mechanical strength and is not braided, so it is easy to remove and handle in terminal treatment and the like. Further, the inventors have found that the noise generated in the coaxial cable due to the rotation and bending of the arrangement portion in the electronic device is the electrostatic noise generated due to the friction between the insulator and the outer conductor. Since the outer conductor of the present invention is spirally wound with one long side of the substantially rectangular shape of the ribbon-shaped conductor facing the insulator, the contact surface between the ribbon-shaped conductor and the insulator has a wider friction. Because of the large size, even when the coaxial cable is bent, the phenomenon that the ripon-shaped conductor moves by rubbing against the insulator does not easily occur, and electrostatic noise is prevented. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a perspective view showing a single-core coaxial cable using a typical coaxial wire of the present invention, and FIG. 2 is a schematic diagram for explaining how to wind a ripon-shaped conductor according to the present invention. FIG. 3 is a schematic view showing a cross section of a flat cable as an example of the multi-core cable of the present invention.

FIG. 4 is a side view showing a conventional coaxial cable using a braid of metal tape. Fifth, a cross-sectional view of the ripon-shaped conductor of the present invention is shown in comparison with a round wire before rolling. FIG. 6 is a diagram illustrating a bending test of a coaxial strand. Fig. 7 shows the twist of the coaxial strand It is a figure explaining a round test. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention will be described in detail with reference to the drawings. The coaxial cable constituting the coaxial cable of the present invention basically has a thickness of the insulator of 0.15 mm or less, and the coaxial cable can be configured to have a small diameter. It is effective for coaxial cables wired in electronic devices and thin flat multi-core cables that are required to be miniaturized. In addition, a copper or copper alloy round wire is rolled and flattened as a lipon-shaped conductor as an outer conductor, and this ripon-shaped conductor is spirally wound on an insulator to form a coaxial strand. FIG. 1 is a perspective view schematically showing a single-core coaxial cable using a typical coaxial wire of the present invention. In FIG. 1, 1 is a central conductor such as copper or a copper alloy, 2 is an insulator made of PFA, polyester, polyimide film, etc., 3 is an outer conductor, and a ribbon having a substantially rectangular cross section and a smooth cross section at four corners. It consists of a conductor. This ripon-shaped conductor can be manufactured by chamfering four corners of a rectangular conductor wire. In addition, copper or copper alloy round wires can be rolled and flattened, which is advantageous in terms of manufacturing cost. The outer conductor 3 is formed by spirally winding the ribbon-shaped conductor around the insulator 2.

(1) Thickness of insulator: Electronic devices such as notebook computers and medical sensors change position and angle by human power, so they are required to be smaller and lighter, and coaxial cables to be used are also laid out in narrow spaces. Is done. For this reason, thinner coaxial cables are required. On the other hand, when the coaxial cable is deformed by the rotation or bending of the arrangement portion, the strain applied to the coaxial cable, especially to the outer conductor, increases as the outer diameter increases, and the noise generation also increases. For this reason, the thickness of the insulator of the coaxial strand of the present invention and the coaxial strand constituting the coaxial cable must be as thin as 0.15 mm or less. On the other hand, although the thickness of the insulator is better as it is thinner, it will be repeatedly deformed by bending and twisting during use, so it will be extremely thin within the range showing moderate mechanical durability and flexibility A value, for example, about 0.03 mm or more is desirable.

(2) Outer conductor: The ripon-shaped conductor that constitutes the outer conductor is made of a rolled and flattened round wire using a metal conductor such as copper or copper alloy, and this ribbon-shaped A conductor is spirally wound on an insulator to form an external conductor. Since the ripon-shaped conductor is obtained by rolling a round wire as described above, the four corners of the cross section have a smooth shape and a substantially rectangular shape without sharp edges on the entire circumference. The outer conductor is formed by winding one long side of a substantially rectangular shape of the ribbon-shaped conductor toward the insulator. As a result of the ribbon-shaped conductor having such a form, it does not have an acute edge like the slit tape of the conventional method, and is not likely to cause damage to the insulator or localization of the voltage, and has a stable withstand voltage characteristic. Obtainable. In addition, by using flattened copper or copper alloy by rolling a round wire as a ribbon-shaped conductor without softening, it can be unwound simply by winding without the need for special braiding as in the conventional method. There is an advantage. The tension when winding the ribbon-shaped conductor does not impair the properties of the insulator, and the coaxial strand or cable is bent or twisted while the wound ribbon-shaped conductor always keeps the strength to tighten the insulator. It is necessary that the tension does not break when the wire is broken, and it is preferably 30% or more and 80% or less of the breaking tension of the ripon-shaped conductor. Further, a layer in which a metal is deposited on a thinner tape may be provided under the outer conductor, in which case the shielding effect can be improved and the dielectric strength characteristics of the insulator can be increased.

The winding angle of the ripon-shaped conductor is preferably 45 ° or more in terms of imparting flexibility, and more preferably 60 ° or more.If the angle is too close to a right angle, productivity is extremely reduced, which is preferable. There is no limit, about 80 degrees. The outer conductor preferably has a thickness of not more than 0.03 mm in order to reduce the outer diameter of the coaxial strand and the coaxial cable, and has a thickness of not less than 0.01 mm from the viewpoint of mechanical strength. Desirably. The width of the ripon-shaped conductor is preferably wide from the viewpoint of maintaining the characteristics as the external conductor, and is preferably 0.1 mm or more.The width is narrow from the viewpoint of workability of winding and cost. Since the material cost is lower and wrinkles during winding are less likely to occur, it is preferable that the thickness is 0.3 mm or less. In particular, from the viewpoints of electrical characteristics, mechanical characteristics, and manufacturability, the outer conductor is a tape with a thickness of 0.025 mm and a width of 0.20 mm produced by rolling a round wire with an outer diameter of 0.08 mm. Conductors and tape-shaped conductors with a thickness of 0.012111111 and a width of 0.18 mm produced by rolling a round wire with an outer diameter of 0.05 mm have excellent properties.

(3) Multi-core cable: In particular, in the case of the multi-core cable of the present invention, coaxial strands are assembled. In both cases where a common jacket is applied, or when a single core coaxial cable is assembled and a common jacket is applied, the outer conductor of the coaxial wire is formed from a round wire by rolling to form an acute angle around the outer circumference. With a smooth surface without edges, etc., even if a force from the side surface, so-called side pressure, acts on the coaxial wire by twisting, etc., there is no risk that the insulator will be damaged by the external conductor, and the withstand voltage of the insulator will decrease. This eliminates the need to worry about multi-core cables while maintaining the mechanical durability and electrical characteristics of the multi-core cables, and enables thinner and thinner multi-core cables. The present invention will be specifically described by the following examples.

(Example 1)

For use as an external conductor, a round wire made of tin-plated copper alloy with an outer diameter of 0.05 mm, whose cross-sectional shape is shown in Fig. 5 (A), is rolled, and the thickness is shown in Fig. 5 (B). A long lipon-shaped conductor having a length of 0.12 mm and a width of 0.18 mm was produced. PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer) resin is applied as an insulator around a 0.09 mm outer diameter center conductor (7 strands of 30 m outer diameter tinplate copper alloy wire). After coating by a known extrusion coating method so as to form a circular outer shape having an outer diameter of 0.23 mm, as shown in FIG. 0 gf Z With one tension, spaced at a pitch of 0.29 mm, spirally wound around the axis of the coaxial wire at an angle of 68 degrees to wind the coaxial wire. Produced.

This coaxial wire was subjected to a withstand voltage test as its basic characteristics, a bending test and a torsion test, and an electrostatic noise test as insulation characteristics when used in a rotating or bent portion. At this time, since the coaxial cable was manufactured by combining coaxial strands in various forms, the evaluation was performed with the coaxial strands in order to evaluate without the influence of the jacket.

Withstand voltage test: Using a 300 m coaxial wire, a DC voltage of 100 V was applied between the center conductor and the outer conductor for 1 minute, and the presence or absence of dielectric breakdown was examined. As a result, no withstand voltage failure in which the insulating layer was destroyed was observed, and characteristics as a good coaxial cable were confirmed.

Mandrel bending test: Fig. 6 schematically shows the test method. The center part of the coaxial strand 20 is sandwiched between two metal rods 22 with an outer diameter of 5 mm, and a load of 50 gf is placed at the lower end. Weight 21 was attached, and the upper end was wrapped 90 degrees around the left and right metal rods and stretched. One bending was performed once for each of the left and right, and the bending was performed 100 times at a speed of 30 times Z. After that, the same pressure resistance test as above was performed, but no pressure failure was recognized, and excellent resistance to repeated bending was confirmed.

Torsion test: Fig. 7 schematically shows the test method. Fix the upper end of the 20 cm long coaxial strand 20 to the upper end fixing point 24, attach a load 23 of 50 gf to the lower end and suspend it vertically.This load 23 is the center axis of the coaxial cable. The work was performed clockwise and counterclockwise alternately by 180 degrees around the axis. With each twist of clockwise and counterclockwise as one twist, after twisting 100,000 times at a speed of 30 times, the same withstand voltage test as above was performed. It was not recognized, and excellent resistance to twisting was confirmed.

Electrostatic noise characteristics: Fig. 7 schematically shows the test method. In addition, to evaluate the magnitude of electrostatic noise when rapid deformation is applied, a 50-cm long coaxial strand is stretched horizontally, a 20-cm-long cotton thread is tied at the center, and the A load of 20 gf was applied to the other end. While measuring the voltage between the center conductor and the outer conductor of the coaxial wire with a voltmeter, the weight was allowed to freely fall from the height of the coaxial wire, and the electrostatic noise characteristics were measured as the maximum value of the voltage fluctuation. . As a result of performing the same measurement 10 times, the maximum value of the voltage fluctuation generated for this coaxial strand was a maximum of 2.5 mV. On the other hand, when the outer conductor of the coaxial wire was changed to the conventional braid shown in Fig. 4 and the same evaluation was performed, voltage fluctuations with the maximum value reaching 100 mV were observed. From these results, it was confirmed that the use of the present invention significantly improved electrostatic noise.

Next, as shown in FIG. 3, the coaxial strands 10 were arranged in parallel and covered with a polyester tape with an adhesive as a jacket 4 to form a flat multicore cable. In addition, a single core coaxial cable is formed by coating the coaxial strand with a single core coaxial cable, and the single core coaxial cable is twisted with 30 cores, and a common jacket is applied to the outside of the single core coaxial cable. A thin multi-core cable was obtained while maintaining mechanical durability. It was confirmed that the multi-core cable obtained in this way also had good properties including insulation properties.

(Example 2) In Example 1, the ribbon-shaped conductor was spirally wound with a tension of 55 gf Zl at a pitch of 0.18 mm and an angle of 75 degrees in a butt winding as shown in FIG. 2 (B). To produce a coaxial strand. The withstand voltage characteristics, bending characteristics, twisting characteristics, and electrostatic noise characteristics of the coaxial strand were also good. Using this coaxial wire, a single-core coaxial cable, a flat multi-core cable and a multi-core cable were produced in the same manner as in Example 1. It was confirmed that the coaxial cable and the multi-core cable obtained in this way also had good properties including insulation properties.

(Example 3)

In Example 1, as shown in FIG. 2 (C), the ripon-shaped conductor was spirally wound at a pitch of 0.29 mm and an angle of 68 degrees under tension of one piece of 65 gf Z (2 pieces in the same direction). Coaxial strands were produced by winding each sheet. In addition, as shown in FIG. 2 (D), a second ribbon-shaped conductor was wound in the opposite direction at a pitch of 0.29 mm and an angle of 68 degrees. The withstand voltage characteristics, bending characteristics, torsion characteristics, and electrostatic noise characteristics of these coaxial wires were good, and the shield characteristics of the outer conductor layer were particularly excellent. Further, with respect to these coaxial strands, a single-core coaxial cable, a flat multi-core cable and a multi-core cable were produced in the same manner as in Example 1. It was confirmed that the coaxial cable and multi-core cable obtained in this way also had good properties including insulation properties. Industrial applicability

As described above, a substantially rectangular ripon-shaped conductor having a smooth cross section at the four corners is used as the external conductor, and the ripon-shaped conductor is spirally wound around the insulator to form a coaxial element without the external conductor. Therefore, by using this coaxial element wire, a thin coaxial cable having flexibility and high mechanical durability can be obtained. A plurality of these simultaneous strands or coaxial cables can be assembled and sheathed to use as a multi-core cable. In addition, by arranging the coaxial cable or multi-core cable obtained in this way in the rotating or bent part of the electronic device, it is possible to obtain an electronic device with excellent insulation characteristics and low electrostatic noise over a long period of time and high quality. Thus, high-speed internal signal transmission can be realized.

Claims

The scope of the claims

1. A coaxial element wire consisting of a center conductor, an insulator, and an outer conductor is provided. The thickness of the insulator is 0.15 mm or less, and a copper or copper alloy round wire is rolled and flattened as the outer conductor. A coaxial element comprising a ribbon-shaped conductor, wherein the ribbon-shaped conductor is spirally wound around the insulator to form a coaxial element.

2. A coaxial strand comprising a center conductor, an insulator, and an outer conductor is provided, and the insulator is provided in contact with and surrounding the center conductor, and the thickness of the insulator is 0.03 mm at the smallest portion. 0.15 mm or less, and the outer conductor is formed by spirally winding one or a plurality of substantially rectangular ripon-shaped conductors having smooth cross-sections at four corners with one long side facing the insulator. The winding angle of the ripon-shaped conductor with respect to the axis of the coaxial strand is 45 degrees or more.

3. The ribbon-shaped conductor is made of a metal containing copper, and is wound around the insulator with a tension of 30% or more of a tensile breaking tension of the ripon-shaped conductor. The coaxial strand described in 2.

4. A coaxial cable, wherein the single coaxial strand according to claim 1 is covered with a jacket.

5. A multi-core cable, wherein a plurality of the coaxial cables according to claim 4 are assembled and coated in common.

6. A multi-core cable, wherein a plurality of coaxial strands according to claims 1 to 3 are assembled to form a common jacket.

7. At least one of the coaxial cable described in claim 4 or the multi-core cable described in claim 5 or 6 is arranged at a position where the electronic device is mechanically rotated or bent. Electronic equipment.