Multicore cable

Abstract

To provide a multicore cable in which generation of noise when twisted is suppressed.SOLUTION: A multicore cable 10 has: a core 11 in which a plurality of coated cables are stranded; a jacket 13 which is arranged outside the core; and a shielding layer 12 which is arranged between the core and the jacket. The shielding layer has a braided conductor in which metal wires are braided, the external diameter of the metal wire is 0.05 mm or more and 0.08 mm or less, the braid density of the braided conductor is 91% or more, and the braid pitch is 5 times or more and 6 times or less the external diameter of the core.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to multi-conductor cables. [Background technology]

[0002] Patent Document 1 discloses a transmission cable that complies with the USB Type-C standard and includes a shield layer. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-10747 A Summary of the Invention [Problem to be solved by the invention]

[0004] In multi-core cables, when a device to which the multi-core cable is connected is used, a force is applied to the multi-core cable, causing the multi-core cable to twist and produce noise, which is known as a phenomenon called "sounding." If sounding occurs repeatedly, depending on the environment in which the multi-core cable is installed, it may cause discomfort to the user. For this reason, there has been a demand for suppressing sounding in multi-core cables.

[0005] Therefore, an object of the present disclosure is to provide a multi-core cable that suppresses noise when twisted. [Means for solving the problem]

[0006] The multi-core cable of the present disclosure includes a core formed by twisting together a plurality of covered electric wires; an outer jacket disposed outside the core; a shielding layer disposed between the core and the jacket, The shielding layer has a braided conductor formed by braiding metal wires, The outer diameter of the metal wire is 0.05 mm or more and 0.08 mm or less, The braided conductor has a braid density of 91% or more and a braid pitch of 5 to 6 times the outer diameter of the core. Effect of the Invention

[0007] According to the present disclosure, it is possible to provide a multi-core cable that suppresses noise when twisted. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a cross-sectional view of a multi-core cable according to one embodiment of the present disclosure taken along a plane perpendicular to the longitudinal direction. [Figure 2A] FIG. 2A is an explanatory diagram of a braided conductor. [Figure 2B] FIG. 2B is an explanatory diagram of the braid pitch. [Diagram 3] FIG. 3 is an explanatory diagram of the noise test. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] The embodiments for carrying out the invention are described below.

[0010] [Description of the embodiments of the present disclosure] First, the embodiments of the present disclosure will be described. In the following description, the same or corresponding elements are denoted by the same reference numerals, and the same description thereof will not be repeated.

[0011] (1) A multi-core cable according to one embodiment of the present disclosure includes: a core formed by twisting together a plurality of covered electric wires; an outer jacket disposed outside the core; a shielding layer disposed between the core and the jacket, The shielding layer has a braided conductor formed by braiding metal wires, The outer diameter of the metal wire is 0.05 mm or more and 0.08 mm or less, The braided conductor has a braid density of 91% or more and a braid pitch of 5 to 6 times the outer diameter of the core.

[0012] It is believed that friction between the shielding layer and the core or the jacket at the loosened portion of the shielding layer is the cause of the noise. By setting the outer diameter, braid density, and braid pitch of the metal wire within a predetermined range, it is believed that the shielding layer is less likely to become loose when the multi-core cable is twisted. Therefore, it is believed that the multi-core cable according to one embodiment of the present disclosure can particularly suppress the noise.

[0013] (2) In a cross section perpendicular to the longitudinal direction of the core, The plurality of coated electric wires are arranged in a plurality of layers from the center of the core, The plurality of covered electric wires disposed on the outer surface of the core may be disposed along a circumscribing circle of the core.

[0014] In the cross section of the core, if the distance from the center of the core to the covered electric wires arranged on the outer surface varies greatly, some covered electric wires will protrude outward from the other covered electric wires, and the covered electric wires will be more likely to come into contact with the shielding layer. It is considered that the covered electric wires protruding outward from the other covered electric wires will come into contact with the shielding layer, which will more likely cause audible noise. In the cross section perpendicular to the longitudinal direction of the core, multiple covered electric wires are arranged in multiple layers from the center of the core, and multiple covered electric wires arranged on the outer surface of the core are arranged along a circumscribing circle, so that the cross section of the core can be made closer to a circle. Therefore, in the cross section perpendicular to the longitudinal direction of the core, it is possible to prevent the covered electric wires from protruding outward from the other covered electric wires. As a result, it is considered that audible noise can be particularly suppressed when the multi-core cable is twisted.

[0015] [Details of the embodiment of the present disclosure] Specific examples of a multi-core cable according to an embodiment of the present disclosure (hereinafter, referred to as the present embodiment) will be described below with reference to the drawings. Note that the present invention is not limited to these examples, but is defined by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0016] In this specification, the names of components may be described with first, second, third, etc. added to them, such as a first electric wire, a second electric wire, a third electric wire, a first conductor, a second conductor, a third conductor, a first insulator, a second insulator, and a third insulator. The first, second, third, etc. are written merely to distinguish each component and to prevent confusion during the description, and do not represent the arrangement, priority, etc. For this reason, when there is no particular risk of confusion or when the components are described together, they may be simply written as electric wire, conductor, and insulator. [Multi-core cable] Fig. 1 shows an example of the configuration of a cross section perpendicular to the longitudinal direction of the multi-core cable of this embodiment. The direction along the Z axis from the paper surface in Fig. 1 corresponds to the longitudinal direction of the multi-core cable 10 and the cores 11. The XY plane is the cross section perpendicular to the longitudinal direction of the multi-core cable 10 and the cores 11.

[0017] 1, the multi-core cable 10 of this embodiment has a core 11 and an outer jacket 13 disposed outside the core 11. The multi-core cable 10 of this embodiment also has a shielding layer 12 disposed between the core 11 and the outer jacket 13.

[0018] Each member contained in the multi-core cable of this embodiment will be described below. (1) Core (1-1) Materials that the core has The core 11 has a plurality of covered wires 20 . (1-1-1) Insulated wire The coated wire 20 of the core 11 is not particularly limited, and can be selected according to the characteristics required for the multi-core cable 10, etc.

[0019] The multi-core cable 10 may have an electric wire or a coaxial wire as the covered electric wire 20. The multi-core cable 10 may also have an uncovered drain wire or the like in addition to the covered electric wire 20 as necessary. The multiple covered electric wires 20 in the multi-core cable 10 may be twisted together to form the core 11.

[0020] The multi-core cable 10 shown in FIG. 1 has, as the covered electric wire 20, a first electric wire 15, a twisted pair electric wire 16, a third electric wire 17, a fourth electric wire 18, and a coaxial wire 19.

[0021] The configuration of the covered electric wire 20 will be described in the order of the first electric wire 15, the second electric wire 161, the third electric wire 17, the fourth electric wire 18, the coaxial wire 19, and the twisted pair electric wire 16. (A) Electric wire The electric wire may have a conductor and an insulator covering the outer surface of the conductor.

[0022] First electric wire 15 in multi-core cable 10 shown in FIG. 1 may have first conductor 151 which is a conductor, and first insulator 152 which is an insulator covering the outer surface of first conductor 151 .

[0023] The second electric wire 161 may have a second conductor 1611 which is a conductor, and a second insulator 1612 which is an insulator covering the outer surface of the second conductor 1611 .

[0024] Moreover, the third electric wire 17 may have a third conductor 171 which is a conductor, and a third insulator 172 which is an insulator covering the outer surface of the third conductor 171 .

[0025] The fourth electric wire 18 may have a fourth conductor 181 which is a conductor, and a fourth insulator 182 which is an insulator covering the outer surface of the fourth conductor 181 .

[0026] An example of the configuration of each member of the electric wire will be described. (A-1) Conductor The conductor may have a single conductor wire or multiple conductor wires. When the conductor has multiple conductor wires, the multiple conductor wires may be twisted together. In other words, when the conductor has multiple conductor wires, the conductor may be a twisted wire of multiple conductor wires.

[0027] The material of the conductor is not particularly limited, and may be, for example, one or more conductor materials selected from copper alloy, copper, silver-plated soft copper, and tin-plated soft copper. Soft copper may also be used as the copper. (A-2) Insulator The material constituting the insulator is not particularly limited, but may include a resin material.

[0028] The resin material may be one or more selected from fluororesins such as polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkylvinylether copolymer (PFA), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), ethylene-tetrafluoroethylene copolymer (ETFE), polyester resins such as polyethylene terephthalate (PET), polyolefin resins such as polyethylene, polypropylene, polymethylpentene, etc. The resin material contained in the insulator may be crosslinked or may not be crosslinked.

[0029] The insulator may be composed only of the above-mentioned resin material, but may also contain, in addition to the resin material, one or more additives selected from a flame retardant, a flame retardant assistant, an antioxidant, a lubricant, a colorant, a reflectivity imparting agent, a masking agent, a processing stabilizer, a plasticizer, and the like. (B) Coaxial line As shown in FIG. 1 , the coaxial cable 19 may have a fifth conductor 191, a fifth insulator 192 covering the outer surface of the fifth conductor 191, an outer conductor 193 covering the outer surface of the fifth insulator 192, and an outer coating 194 covering the outer surface of the outer conductor 193.

[0030] The fifth conductor 191 and the fifth insulator 192 can have the same configuration as the conductor and insulator described for the electric wire, for example, and therefore a description thereof will be omitted.

[0031] The outer conductor 193 and the outer coating 194 will now be described. (B-1) Outer conductor The outer conductor 193 may include, for example, a metal wire, a metal foil, or a metal film (evaporated film).

[0032] When the outer conductor 193 has a metal wire, for example, a plurality of metal wires may be wound laterally or twisted together to form a braid. The material of the metal wire may be, for example, copper, a copper alloy, aluminum, an aluminum alloy, or the like. The metal wire may also be a soft copper wire or a hard copper wire. The surface of the metal wire may be plated with silver or tin. For this reason, the metal wire may be, for example, a silver-plated copper alloy or a tin-plated copper alloy.

[0033] When the external conductor 193 has a metal foil or a metal film, the material of the metal foil or the metal film can be, for example, copper, a copper alloy, aluminum, an aluminum alloy, etc. When the external conductor 193 has a metal foil or a metal film, the external conductor 193 can be formed by, for example, arranging a conductive tape having a metal foil or a metal film on a base material on the outer surface of the fifth insulator 192. (B-2) Outer periphery coating The outer circumferential coating 194 may include a resin material, such as one or more materials selected from the group consisting of polyolefin, polyester, polyvinyl chloride (PVC), and fluororesin.

[0034] In addition to the resin material, the outer coating 194 may also contain various additives such as a flame retardant.

[0035] The resin material of the outer circumferential coating 194 may or may not be crosslinked. (C) Twisted pair wire For example, a part of the covered electric wires 20 of the core 11 may be twisted in advance to form a twisted pair electric wire or the like. In the case of the multi-core cable 10 shown in FIG. (1-2) Core configuration The core 11 may have a configuration in which a plurality of covered electric wires 20 are twisted together.

[0036] The configuration in which multiple covered electric wires 20 are twisted together is not particularly limited. For example, as shown in FIG. 1, multiple covered electric wires 20 may be arranged in multiple layers from the center of core 11 in a cross section perpendicular to the longitudinal direction of core 11.

[0037] In the multi-core cable 10 shown in FIG. 1, a core 11 has a plurality of covered electric wires 20 arranged and twisted together to form two layers, a first layer 111 and a second layer 112.

[0038] The multiple covered electric wires 20 arranged on the outer surface of the core 11, i.e., in the outermost layer, may be arranged along the circumscribing circle C11 of the core 11. In the case of the multi-core cable 10 shown in Fig. 1, the covered electric wires 20 arranged in the second layer 112 become the covered electric wires 20 arranged on the outer surface.

[0039] In a cross section perpendicular to the longitudinal direction of the core, if the distances of the coated electric wires 20 arranged on the outer surface from the center of the core 11 vary greatly, some coated electric wires 20 will protrude outward from the other coated electric wires 20, and the coated electric wires 20 will be more likely to come into contact with the shielding layer 12. It is considered that the coated electric wires 20 protruding outward from the other coated electric wires 20 will be more likely to make noise when they come into contact with the shielding layer 12. In a cross section perpendicular to the longitudinal direction of the core, the multiple coated electric wires 20 are arranged in multiple layers from the center of the core 11, and the multiple coated electric wires 20 arranged on the outer surface of the core 11 are arranged along the circumscribed circle C11, so that the cross section of the core 11 can be made closer to a circle. Therefore, in a cross section perpendicular to the longitudinal direction of the core 11, it is possible to suppress the occurrence of coated electric wires protruding outward from the other coated electric wires. As a result, it is considered that it is possible to particularly suppress noise when the multi-core cable is twisted. (2) Shielding layer The shielding layer 12 may be disposed between the core 11 and the jacket 13 .

[0040] The multi-core cable 10 having the shielding layer 12 can suppress noise from being carried on the signal propagating through the covered electric wire 20. In addition, the influence of noise on external devices can be suppressed.

[0041] The inventors of the present invention have investigated a multi-core cable that can suppress the generation of audible noise when twisted. As a result, they have found that the generation of audible noise can be suppressed by selecting the configuration of the shielding layer, and have completed the present invention.

[0042] Therefore, the shielding layer 12 of the multicore cable 10 of the present embodiment can have a braided conductor 200 in which metal wires 21 are braided, as shown in Fig. 2A. As shown in Fig. 2A, the braided conductor 200 can have a structure in which metal wire bundles 22, which are multiple metal wires 21, are braided so that they cross each other, and the intersections have stitches 23. The number of metal wire bundles 22, which are multiple metal wires 21, that the braided conductor 200 has may be expressed as the number of strands, and the number of metal wires 21 that the metal wire bundles 22 have may be expressed as the number of wires.

[0043] The material of the metal wire 21 used in the braided conductor 200 of the shielding layer 12 is not particularly limited, but may be, for example, a metal material such as copper, a copper alloy, aluminum, an aluminum alloy, or a material having a plated surface thereof, such as tin-plated soft copper or silver-plated soft copper. Soft copper may also be used as the copper.

[0044] The outer diameter D21 of the metal wire 21 can be set to 0.05 mm or more and 0.08 mm or less.

[0045] Braided conductor 200 may have a braid density of 91% or more, and may be 91% or more and 95% or less.

[0046] The braid density means the ratio of the area occupied by the metal wires 21 to the unit area of ​​the braided conductor 200.

[0047] In the braided conductor 200, a metal wire bundle 22, which is a bundle of multiple metal wires 21 arranged in parallel, is braided around the outer periphery of the core 11. Therefore, the same metal wire bundle 22 appears at a constant pitch along the length of the core 11.

[0048] 2B is a schematic diagram illustrating only one bundle of metal wires 22 included in braided conductor 200 arranged on the outer periphery of core 11, for the purpose of explaining braid pitch P. As shown in FIG. 2B, the cable length when metal wires 22 included in braided conductor 200 go around core 11 along the longitudinal direction of core 11 is the braid pitch P.

[0049] In the multi-core cable 10 of the present embodiment, the braid pitch P can be set to 5 to 6 times the outer diameter D11 of the core 11.

[0050] It is believed that friction between the shielding layer 12 and the core or jacket at loosened portions of the shielding layer 12 is the cause of the noise. By setting the outer diameter D21, braid density, and braid pitch of the metal wires 21 within predetermined ranges, it is believed that the shielding layer is less likely to become loose when the multi-core cable 10 is twisted. Therefore, it is believed that the multi-core cable 10 of this embodiment can particularly suppress the occurrence of noise by suppressing contact of loosened portions of the braided wires with the outer surface of the core 11.

[0051] When the pressure winding 14 is disposed on the outer surface of the core 11 , the outer diameter of the pressure winding 14 becomes the outer diameter D11 of the core 11 . (3) Outer covering An outer jacket 13 may be disposed on the outside of the core 11 .

[0052] There is no particular limitation on the material of the outer jacket 13. The outer jacket 13 may include a resin material. Examples of the resin material include polyolefins such as polyethylene, polyvinyl chloride (PVC), and thermoplastic elastomers (TPE).

[0053] In addition to the above-mentioned resin materials, the jacket 13 may also contain various additives such as a flame retardant.

[0054] The material of the jacket 13 may or may not be crosslinked.

[0055] The multi-core cable 10 has an outer sheath 13, which makes it possible to protect the covered electric wires 20 and the shielding layer 12 arranged inside. (4) Pressing Multi-conductor cable 10 may also have a retainer winding 14 covering the outer surface of core 11 .

[0056] By providing the multi-core cable 10 with the retaining winding 14, the arrangement of the covered electric wires 20 of the multi-core cable 10 can be stabilized and bundled.

[0057] The retainer roll 14 may be, for example, a resin tape, a paper tape, or a nonwoven tape.

[0058] Examples of resins used for the resin tape include one or more types selected from fluororesins such as polytetrafluoroethylene (PTFE) resin, which have excellent heat resistance and abrasion resistance, polyester resins such as polyethylene terephthalate (PET) resin, and polyethylene (PE).

[0059] The resin tape used as the pressure roll 14 may contain a conductive material such as carbon to provide electrical conductivity. The conductive material may be added so as to be dispersed in the resin constituting the resin tape. Alternatively, a metal tape having, for example, copper foil or aluminum foil disposed on the surface of the resin tape may be used.

[0060] The winding direction of the pressure winding 14 may be the same as or opposite to the twisting direction of the covered electric wires 20 constituting the core 11.

[0061] By providing the multi-core cable 10 with the retaining winding 14, it is possible to prevent the insulation of the covered wires 20 that constitute the core 11 from being damaged when the shielding layer 12 is disposed on the outside of the core 11. EXAMPLES

[0062] The present invention will be described below with reference to specific examples, but is not limited to these examples. (Evaluation method) First, the method for evaluating the multi-core cables produced in the following experimental examples will be described. (1) Outer diameter of core D11, outer diameter of shielding layer D12, outer diameter of multi-core cable D10, outer diameter of metal wire D21 The outer diameter D11 of the core 11, the outer diameter D12 of the shielding layer 12, the outer diameter D10 of the multi-core cable 10, and the outer diameter D21 of the metal wire of the multi-core cable produced in the following experimental examples were measured according to the method described in JIS C 3005 (2014).

[0063] A micrometer is used to measure the outer diameter D21 of metal wires, and a vernier caliper is used to measure the outer diameter of items other than metal wires.

[0064] Specifically, in any one cross section perpendicular to the longitudinal direction of multi-core cable 10 or metal wire 21, the lengths of two perpendicular diameters were measured for each portion to be measured, and the average value was taken as the outer diameter of each portion. (2) Braid density The braid density of braided conductor 200 in shielding layer 12 of multicore cable 10 produced in the following experimental examples was calculated according to the following formulas (1), (2), and (3).

[0065]

number

[0066]

number

[0067]

number

[0068] In equations (1), (2), and (3), γ represents the braid density (%), N represents the number of strands, C represents the number of strands, d represents the outer diameter D21 of the metal wire in the braided conductor 200, P represents the braid pitch (mm), and D represents the outer diameter D11 of the core (mm). (3) Braid pitch The metal wire bundle 22 to be measured was identified, and the cable length when the identified metal wire bundle 22 went around the core 11 along the longitudinal direction of the core was measured and defined as the braid pitch P. (4) Sound test As shown in Fig. 3, multi-core cable 10 having a length of 0.2 m produced in the following experimental example was allowed to hang vertically, and the upper and lower ends of multi-core cable 10 were held by chucks 31 and 32, respectively. A load of 2 N was applied downward to multi-core cable 10 along block arrow 33 in Fig. 3.

[0069] Then, with the lower chuck 32 fixed, the upper chuck 31 was twisted left and right along the double arrow 35 with the axis 34 of the multi-core cable 10 as the rotation axis, at a speed of one round trip every three seconds between -90° and +90°.

[0070] In this case, the observer's ear was positioned within 10 to 50 mm of the multi-core cable, and if the observer could hear the sound, the observer was given an evaluation of B, and if the observer could not hear the sound, the observer was given an evaluation of A.

[0071] If the rating is A, the cable is evaluated as being a multi-core cable that suppresses noise when twisted. (Experimental conditions and results) The multi-core cables in each experimental example are described below.

[0072] Multi-core cables were produced according to the following Experimental Examples 1 and 2. Experimental Example 1 is a comparative example, and Experimental Example 2 is an embodiment of the present invention. [Experimental Example 1] A multi-core cable 10 having the cross-sectional structure perpendicular to its longitudinal direction shown in FIG. 1 was produced.

[0073] 1, in a cross section perpendicular to the longitudinal direction of the multi-core cable 10, a plurality of covered electric wires 20 are arranged and twisted together so as to form two layers, a first layer 111 and a second layer 112, from the center of the core 11. The plurality of covered electric wires 20 arranged on the outer surface of the core 11 are arranged along the circumscribing circle C11 of the core 11. Each covered electric wire 20 of the core 11 has already been described, and therefore description thereof will be omitted.

[0074] Outside the core 11, a pressure winding 14, a shielding layer 12, and an outer jacket 13 are arranged in that order from the position closest to the core 11.

[0075] The configuration of the braided conductor 200 of the shielding layer 12 is as shown in the "Braid" column of Table 1.

[0076] The evaluation results are shown in Table 1. [Experimental Example 2] The outer diameter D21 of the metal wire used in the shielding layer 12 and the configuration of the braided conductor were changed to the values ​​shown in Table 1. A multi-core cable 10 was produced under the same conditions as in Experimental Example 1 except for the above points. The evaluation results are shown in Table 1.

[0077] [Table 1] [Explanation of symbols]

[0078] 10 Multi-core cable D10 Outer diameter of multi-core cable 11 cores 111 First layer 112 Second layer C11 circumscribed circle D11 Core outer diameter 12 Shielding layer 13 Outer cover 14 Retainer roll 15 Daiichi Electric Cable 151 First Conductor 152 First Insulator 16 Twisted pair wire 161 Second electric wire 1611 Second Conductor 1612 Second Insulator 17 Third electric wire 171 Third Conductor 172 Third Insulator 18 Fourth electric wire 181 Fourth Conductor 182 The fourth insulator 19 coaxial line 191 Fifth Conductor 192 Fifth Insulator 193 Outer conductor 194 Outer covering 20. Insulated Wire 200 Braided Conductor 21 Metal Wire D21 Outside diameter of metal wire 22 Metal wire bundle 23 stitches P Braid pitch 31 Chuck 32 Chuck 33 Block Arrow 34 Axis 35 Double Arrow

Claims

1. A core in which a plurality of coated electric wires are twisted together; an outer jacket disposed outside the core; a shielding layer disposed between the core and the jacket, The shielding layer has a braided conductor formed by braiding metal wires, The outer diameter of the metal wire is 0.05 mm or more and 0.08 mm or less, A multi-core cable, wherein the braided conductor has a braid density of 91% or more and a braid pitch of 5 to 6 times the outer diameter of the core.

2. In a cross section perpendicular to the longitudinal direction of the core, The plurality of coated electric wires are arranged in a plurality of layers from the center of the core, The multi-core cable according to claim 1 , wherein the plurality of covered electric wires arranged on the outer surface of the core are arranged along a circumscribing circle of the core.

Images