Multi-core cable

Abstract

The present disclosure provides a multi-core cable in which generation of sound during twisting is suppressed. A multi-core cable is provided with: a core formed by twisting a plurality of coated wires; an outer skin disposed outside the core; and a shield layer disposed between the core and the sheath, the shield layer having a braided conductor formed by braiding metal wires, the outer diameter of the metal wires being 0.05 mm or more and 0.08 mm or less, the braiding density of the braided conductor being 91% or more, and the braiding pitch of the braided conductor being 5 times or more and 6 times or less of the outer diameter of the core.

Description

Technical Field

[0001] The present disclosure relates to a multi-core cable. Background Art

[0002] Patent Document 1 discloses a transmission cable that complies with the USB (Universal Serial Bus) Type-C standard and includes a shielding layer.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2017-10747

[0006] In a multi-core cable, when a force is applied to the multi-core cable during use of a device connected to the multi-core cable, a phenomenon called sound (sound) may occur due to the twisting of the multi-core cable. If the sound is repeatedly generated, it may cause discomfort to the user depending on the installation environment of the multi-core cable. Therefore, in a multi-core cable, it is sometimes required to suppress the sound. Summary of the invention

[0007] Therefore, an object of the present disclosure is to provide a multi-core cable that suppresses noise during twisting.

[0008] The multi-core cable disclosed herein comprises: a core formed by twisting a plurality of covered electric wires; a sheath arranged outside the core; and a shielding layer arranged between the core and the sheath, the shielding layer comprising a braided conductor formed by braiding metal wires, the outer diameter of the metal wires being greater than 0.05 mm and less than 0.08 mm, the braiding density of the braided conductor being greater than 91%, and the braiding pitch of the braided conductor being greater than 5 times and less than 6 times the outer diameter of the core.

[0009] Effects of the Invention

[0010] According to the present disclosure, it is possible to provide a multi-core cable in which noise during twisting is suppressed. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 This 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.

[0012] Figure 2A This is an illustration of a braided conductor.

[0013] Figure 2B This is a diagram to explain the weaving pitch.

[0014] Figure 3 This is a diagram for explaining the sound test.

[0015] Description of Reference Numerals

[0016] 10: Multi-core cable

[0017] D10: outer diameter of multi-core cable

[0018] 11: Core

[0019] 111: First floor

[0020] 112: Second floor

[0021] C11: Circumcircle

[0022] D11: outer diameter of the core

[0023] 12: Shielding layer

[0024] 13: Skin

[0025] 14: Pressing

[0026] 15: First Wire

[0027] 151: First conductor

[0028] 152: First Insulator

[0029] 16: Twisted pair wire

[0030] 161: Second wire

[0031] 1611: Second conductor

[0032] 1612: Second insulator

[0033] 17: Third Wire

[0034] 171: Third conductor

[0035] 172: The third insulator

[0036] 18: Fourth Wire

[0037] 181: The fourth conductor

[0038] 182: The Fourth Insulator

[0039] 19: Coaxial cable

[0040] 191: The Fifth Conductor

[0041] 192: The Fifth Insulator

[0042] 193: External conductor

[0043] 194: Peripheral covering

[0044] 20: Covered wire

[0045] 200: Braided conductor 21: Metal wire D21: Outer diameter of metal wire 22: Metal wire bundle 23: Mesh P: Braiding pitch 31: Chuck

[0046] 32: Chuck

[0047] 33: hollow arrow 34: axis 35: double-headed arrow. DETAILED DESCRIPTION

[0048] Hereinafter, specific implementation methods will be described.

[0049] [Description of Embodiments of the Present Disclosure]

[0050] First, the embodiments of the present disclosure will be described by way of example. In the following description, the same reference numerals are given to the same or corresponding elements, and the same description thereof will not be repeated.

[0051] (1) A multi-core cable of one embodiment of the present invention comprises: a core formed by twisting a plurality of covered electric wires; a sheath arranged outside the core; and a shielding layer arranged between the core and the sheath, the shielding layer comprising a braided conductor formed by braiding metal wires, the outer diameter of the metal wires being greater than 0.05 mm and less than 0.08 mm, the braiding density of the braided conductor being greater than 91%, and the braiding pitch of the braided conductor being greater than 5 times and less than 6 times the outer diameter of the core.

[0052] It is believed that the friction between the core and the outer skin at the part where the shield layer is loose is the cause of the noise. It is believed that by setting the outer diameter, braiding density, and braiding pitch of the metal wire within a specified range, it is less likely that the shield layer will be loosened when the multi-core cable is twisted. Therefore, it is believed that the multi-core cable of one embodiment of the present disclosure can particularly suppress the noise.

[0053] (2) In a cross section of the core perpendicular to the longitudinal direction, the plurality of covered electric wires may be arranged to form a plurality of layers from the center of the core, and the plurality of covered electric wires arranged on the outer surface of the core may be arranged along a circumscribed circle of the core.

[0054] In the cross section of the core, if the distance between the covered electric wires arranged on the outer surface and the center of the core is greatly uneven, a covered electric wire protruding outwards than other covered electric wires will be generated, and the covered electric wire is easy to contact the shielding layer. In addition, it is believed that the covered electric wire protruding outwards than other covered electric wires is easy to generate sound due to the contact of the shielding layer with the covered electric wires protruding outwards. In the cross section of the core perpendicular to the length direction, multiple covered electric wires are arranged to form multiple layers from the center of the core, and multiple covered electric wires arranged on the outer surface of the core are arranged along the circumscribed circle, so that the cross section of the core can be close to a circle. Therefore, it is possible to suppress the generation of covered electric wires protruding outwards than other covered electric wires in the cross section of the core perpendicular to the length direction. As a result, it is believed that when the multi-core cable is twisted, the sound can be particularly suppressed.

[0055] [Details of the embodiments of the present disclosure]

[0056] Hereinafter, a specific example of a multi-core cable of an embodiment of the present disclosure (hereinafter, referred to as "this embodiment") is described with reference to the accompanying drawings. It should be noted that the present invention is not limited to these examples, but is shown by the claims, and is intended to include all changes within the meaning and scope equivalent to the claims.

[0057] In this specification, the names of components may be described by adding first, second, third, etc., such as first electric wire, second electric wire, third electric wire, first conductor, second conductor, third conductor, first insulator, second insulator, and third insulator. First, second, third, etc. are only recorded to distinguish each component and prevent confusion during description, and do not indicate arrangement, priority, etc. Therefore, when there is no particular concern about confusion and the description is summarized, it can be recorded as a wire, a conductor, and an insulator.

[0058] [Multi-core cable]

[0059] Figure 1 2 shows a configuration example of a cross section perpendicular to the longitudinal direction of the multi-core cable of the present embodiment. Figure 1 The direction along the Z axis from the paper surface in φ corresponds to the longitudinal direction of the multi-core cable 10 and the core 11. The XY plane is a cross section perpendicular to the longitudinal direction of the multi-core cable 10 and the core 11.

[0060] like Figure 1 As shown, the multi-core cable 10 of the present embodiment includes a core 11 and a sheath 13 disposed outside the core 11. In addition, the multi-core cable 10 of the present embodiment includes a shield layer 12 disposed between the core 11 and the sheath 13.

[0061] Each member included in the multi-core cable of this embodiment will be described.

[0062] (1) core

[0063] (1-1) Components of the core

[0064] The core 11 has a plurality of covered electric wires 20 .

[0065] (1-1-1) Regarding covered electric wires

[0066] The covered electric 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 .

[0067] The multicore cable 10 may include electric wires or coaxial wires as the covered electric wires 20. If necessary, the multicore cable 10 may include an uncovered drain wire in addition to the covered electric wires 20. The core 11 may be formed by twisting a plurality of covered electric wires 20 included in the multicore cable 10.

[0068] Figure 1 The multi-core cable 10 shown includes 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 as a coated electric wire 20 .

[0069] The structure of the covered electric wire 20 will be described in the order of the electric wire, the coaxial wire 19 , and the twisted pair electric wire 16 . The electric wire is the first electric wire 15 , the second electric wire 161 , the third electric wire 17 , and the fourth electric wire 18 .

[0070] (A) Wires

[0071] An electrical wire may have a conductor and an insulator covering an outer surface of the conductor.

[0072] exist Figure 1 In the case of the first electric wire 15 in the multi-core cable 10 shown, it may include a first conductor 151 as a conductor and a first insulator 152 as an insulator covering the outer surface of the first conductor 151 .

[0073] In the case of the second electric wire 161 , there may be a second conductor 1611 as a conductor and a second insulator 1612 as an insulator covering the outer surface of the second conductor 1611 .

[0074] Furthermore, in the case of the third electric wire 17 , there may be a third conductor 171 as a conductor and a third insulator 172 as an insulator covering the outer surface of the third conductor 171 .

[0075] In the case of the fourth electric wire 18 , there may be a fourth conductor 181 as a conductor and a fourth insulator 182 as an insulator covering the outer surface of the fourth conductor 181 .

[0076] A configuration example of each member included in the electric wire will be described.

[0077] (A-1) Conductor

[0078] The conductor may include a single conductor wire or a plurality of conductor wires. When the conductor includes a plurality of conductor wires, the plurality of conductor wires may be twisted in advance. That is, when the conductor includes a plurality of conductor wires, the conductor may include a twisted wire of the plurality of conductor wires.

[0079] The material of the conductor is not particularly limited, but for example, one or more conductor materials selected from copper alloy, copper, silver-plated annealed copper, and tin-plated annealed copper can be used. Soft copper can also be used as copper.

[0080] (A-2) Insulator

[0081] The material constituting the insulator is not particularly limited but may include a resin material.

[0082] For example, one or more selected from fluororesins such as polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), ethylene-tetrafluoroethylene copolymer (ETFE), polyester resins such as polyethylene terephthalate (PET), and polyolefin resins such as polyethylene, polypropylene, and polymethylpentene can be used as the resin material. The resin material contained in the insulator may be cross-linked or not.

[0083] The insulator may be composed only of the above-mentioned resin material, but in addition to the resin material, the insulator may also contain one or more additives selected from flame retardants, flame retardant aids, antioxidants, lubricants, colorants, reflectivity imparting agents, masking agents, processing stabilizers, plasticizers, etc.

[0084] (B) Coaxial cable

[0085] like Figure 1 As shown, the coaxial line 19 may include: 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 peripheral coating 194 covering the outer surface of the outer conductor 193 .

[0086] The fifth conductor 191 and the fifth insulator 192 can have the same configuration as the conductor and the insulator described in the electric wire section, for example, and thus description thereof is omitted.

[0087] The outer conductor 193 and the outer peripheral cover 194 are described.

[0088] (B-1) External conductor

[0089] The outer conductor 193 may include, for example, a metal wire, a metal foil, or a metal film (evaporated film).

[0090] When the outer conductor 193 has a metal wire, for example, a material obtained by twisting a plurality of metal wires in a manner of horizontal winding or braiding can be used. For example, copper, copper alloy, aluminum, aluminum alloy, etc. can be used as the material of the metal wire. Soft copper wire or hard copper wire can also be used as the metal wire. The surface of the metal wire can also be silver-plated or tin-plated. Therefore, for example, silver-plated copper alloy, tin-plated copper alloy, etc. can also be used as the metal wire.

[0091] When the outer conductor 193 has a metal foil or a metal film, for example, copper, copper alloy, aluminum, aluminum alloy, etc. can be used as the material of the metal foil or the metal film. When the outer conductor 193 has a metal foil or a metal film, for example, the outer conductor 193 can be formed by arranging a conductive tape having a metal foil or a metal film arranged on a base material on the outer surface of the fifth insulator 192.

[0092] (B-2) Peripheral covering

[0093] The outer peripheral coating 194 may include a resin material, and examples of the resin material include one or more selected from polyolefin, polyester, polyvinyl chloride (PVC), and fluororesin.

[0094] The outer peripheral coating 194 may contain various additives such as a flame retardant in addition to the resin material.

[0095] The resin material of the outer peripheral coating 194 may or may not be cross-linked.

[0096] (C) Twisted pair wire

[0097] For example, a portion of the coated electric wires 20 of the core 11 may be twisted in advance to form a twisted pair of electric wires. Figure 1 In the case of the multi-core cable 10 shown, two second electric wires 161 are twisted together to form a twisted pair electric wire 16 .

[0098] (1-2) Core composition

[0099] The core 11 may have a structure in which a plurality of covered electric wires 20 are twisted together.

[0100] The structure when the plurality of covered electric wires 20 are twisted is not particularly limited, but for example Figure 1 As shown, in a cross section of the core 11 perpendicular to the longitudinal direction, the plurality of covered electric wires 20 may be arranged so as to form a plurality of layers from the center of the core 11 .

[0101] exist Figure 1 In the illustrated multi-core cable 10 , the plurality of covered electric wires 20 are arranged to form two layers of a first layer 111 and a second layer 112 with respect to the core 11 , and the plurality of covered electric wires 20 are twisted.

[0102] Furthermore, the plurality of covered electric wires 20 arranged on the outer surface of the core 11, that is, the outermost layer, may be arranged along the circumscribed circle C11 of the core 11. Figure 1 In the case of the multi-core cable 10 shown, the covered electric wire 20 arranged in the second layer 112 is the covered electric wire 20 arranged on the outer surface.

[0103] In the cross section perpendicular to the longitudinal direction of the core, if the distance between the covered electric wire 20 arranged on the outer surface and the center of the core 11 is greatly uneven, a covered electric wire 20 protruding outwards than other covered electric wires 20 will be generated, and the covered electric wire 20 is likely to contact the shielding layer 12. And it is believed that the covered electric wire 20 protruding outwards than other covered electric wires 20 is likely to contact the shielding layer 12, and it is easy to generate noise. In the cross section perpendicular to the longitudinal direction of the core, a plurality of covered electric wires 20 are arranged to form a plurality of layers from the center of the core 11, and a plurality of covered 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 close to a circle. Therefore, it is possible to suppress the generation of a covered electric wire 20 protruding outwards than other covered electric wires 20 in the cross section perpendicular to the longitudinal direction of the core 11. As a result, it is believed that the noise can be particularly suppressed when the multi-core cable is twisted.

[0104] (2) Shielding layer

[0105] The shielding layer 12 may be disposed between the core 11 and the sheath 13 .

[0106] The multi-core cable 10 includes the shield layer 12, thereby being able to suppress the superposition of noise on the signal propagated by the covered electric wire 20. In addition, the influence of the noise on the external device can be suppressed.

[0107] The inventors of the present invention studied a multi-core cable that can suppress the generation of noise when twisted. As a result, they found that the generation of noise can be suppressed by selecting the structure of the shield layer, and completed the present invention.

[0108] Therefore, if Figure 2A As shown, the shielding layer 12 of the multi-core cable 10 of this embodiment may include a braided conductor 200 formed by braiding metal wires 21. Figure 2A As shown, the braided conductor 200 may have a structure in which the metal wire bundles 22 as the plurality of metal wires 21 are braided in a mutually intersecting manner and have meshes 23 at their intersections. Sometimes, the number of the metal wire bundles 22 as the plurality of metal wires 21 included in the braided conductor 200 is recorded as the number of ingots, etc., and the number of the metal wires 21 included in the metal wire bundles 22 is recorded as the number of strands.

[0109] The material of the metal wire 21 used in the braided conductor 200 of the shield layer 12 is not particularly limited, but for example, metal materials such as copper, copper alloy, aluminum, and aluminum alloy, or tin-plated soft copper, silver-plated soft copper, etc., which are materials plated on the surface of these materials, can be used. Soft copper can also be used as copper.

[0110] Furthermore, the outer diameter D21 of the metal wire 21 can be set to be greater than or equal to 0.05 mm and less than or equal to 0.08 mm.

[0111] The braiding density of the braided conductor 200 may be set to 91% or more, or may be set to 91% or more and 95% or less.

[0112] The braiding density refers to the ratio of the area occupied by the metal wires 21 per unit area of ​​the braided conductor 200 .

[0113] In the braided conductor 200, a metal wire bundle 22, which is a bundle of a plurality of metal wires 21 arranged, is braided on the outer periphery of the core 11. Therefore, along the longitudinal direction of the core 11, the same metal wire bundle 22 appears at a fixed pitch.

[0114] Figure 2B 2 is a schematic diagram showing only one bundle of metal wires 22 included in the braided conductor 200 disposed on the outer periphery of the core 11 in order to explain the braiding pitch P. Figure 2B As shown, the cable length when the metal wire bundle 22 included in the braided conductor 200 is wound around the core 11 once along the longitudinal direction of the core 11 is the braiding pitch P.

[0115] In the multi-core cable 10 of the present embodiment, the braiding pitch P can be set to be 5 times or more and 6 times or less the outer diameter D11 of the core 11 .

[0116] The friction between the core and the outer skin at the loose part of the shield layer 12 is considered to be the cause of the noise. It is considered that by setting the outer diameter D21, braiding density, and braiding pitch of the metal wire 21 within a predetermined range, the shield layer is less likely to be loose when the multi-core cable 10 is twisted. Therefore, in the multi-core cable 10 of this embodiment, it is considered that the loose part of the braided wire can be suppressed from contacting the outer surface of the core 11, thereby suppressing the generation of noise.

[0117] When the compression coil 14 is disposed on the outer surface of the core 11 , the outer diameter of the compression coil 14 becomes the outer diameter D11 of the core 11 .

[0118] (3) Skin

[0119] The outer skin 13 may be disposed outside the core 11 .

[0120] The material of the outer skin 13 is not particularly limited. The outer skin 13 may include a resin material. Examples of the resin material include polyolefins such as polyethylene, polyvinyl chloride (PVC), and thermoplastic elastomers (TPE).

[0121] The outer cover 13 may contain various additives such as a flame retardant in addition to the above-mentioned resin material.

[0122] The material of the outer skin 13 may or may not be cross-linked.

[0123] Since the multi-core cable 10 has the outer sheath 13 , the covered electric wires 20 and the shield layer 12 arranged inside can be protected.

[0124] (4) Rolling

[0125] The multi-core cable 10 may also have a crimp 14 covering the outer surface of the core 11 .

[0126] Since the multi-core cable 10 has the crimp 14, the arrangement of the coated electric wires 20 included in the multi-core cable 10 can be stabilized and the covered electric wires 20 can be bundled.

[0127] For example, a resin tape, a paper tape, or a nonwoven fabric tape can be used as the press roll 14 .

[0128] As the resin used for the resin belt, one or more selected from fluororesins such as polytetrafluoroethylene (PTFE) resin, polyester resins such as polyethylene terephthalate (PET) resin, polyethylene (PE), etc., which are excellent in heat resistance and abrasion resistance, etc., are mentioned.

[0129] In order to have conductivity, the resin tape used as the roll 14 may also contain a conductive material such as carbon. The conductive material may be added in a manner dispersed in the resin constituting the resin tape. In addition, for example, a metal tape having copper foil or aluminum foil disposed on the surface of the resin tape may also be used.

[0130] The winding direction of the press coil 14 may be the same direction as the twisting direction of the covered electric wires 20 constituting the core 11 , or may be the opposite direction to the twisting direction of the covered electric wires 20 .

[0131] Since the multi-core cable 10 has the crimp 14 , when the shield layer 12 is disposed outside the core 11 , it is possible to prevent the insulation of the coated electric wire 20 constituting the core 11 from being damaged.

[0132] [Example]

[0133] Hereinafter, specific examples will be given for description, but the present invention is not limited to these examples.

[0134] (Evaluation method)

[0135] First, a method for evaluating a multi-core cable produced in the following experimental example will be described.

[0136] (1) The outer diameter of the core is D11, the outer diameter of the shield is D12, the outer diameter of the multi-core cable is D10, and the outer diameter of the metal wire is D21

[0137] The outer diameter D11 of the core 11, the outer diameter D12 of the shield 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 C3005 (2014).

[0138] A micrometer was used to measure the outer diameter D21 of the metal wire, and a vernier caliper was used to measure the outer diameters other than the metal wire.

[0139] Specifically, in any cross section perpendicular to the longitudinal direction of the multi-core cable 10 or the metal wire 21, the lengths of two orthogonal diameters are measured for each portion to be measured, and the average value is set as the outer diameter of each portion.

[0140] (2) Weaving density

[0141] The braiding density of the braided conductor 200 included in the shield layer 12 of the multi-core cable 10 produced in the following experimental example was calculated by the following equations (1), (2), and (3).

[0142] [Formula 1]

[0143] γ=(2F-F2)×100……(1)

[0144] [Formula 2]

[0145]

[0146] [Formula 3]

[0147]

[0148] In formula (1), formula (2), and formula (3), γ refers to the braiding density (%), N refers to the number of strands, C refers to the number of spindles, d refers to the outer diameter D21 of the metal wire of the braided conductor 200, P refers to the braiding pitch (mm), and D refers to the outer diameter D11 (mm) of the core.

[0149] (3) Weaving spacing

[0150] The metal wire bundle 22 to be measured is determined, and the cable length when the determined metal wire bundle 22 is wound around the core 11 is measured along the longitudinal direction of the core 11, and the braiding pitch P is set as the cable length.

[0151] (4) Sound test

[0152] like Figure 3 As shown in FIG. 1 , a multi-core cable 10 with a length of 0.2 m produced in the following experimental example is hung vertically, and the upper end and the lower end of the multi-core cable 10 are grasped by chucks 31 and 32, respectively. Figure 3 The hollow arrow 33 in FIG. 1 applies a load of 2N downward to the multi-core cable 10 .

[0153] Then, with the lower chuck 32 fixed, the upper chuck 31 is twisted left and right between -90° and +90° along the double-headed arrow 35 at a speed of one reciprocation every 3 seconds, with the axis 34 of the multi-core cable 10 as the rotation axis.

[0154] At this time, the observer's ear was placed within a distance of 50 mm from the multi-core cable 10, and the observer's evaluation was B when the sound was heard, and A when the sound was not heard.

[0155] When the evaluation is A, it can be evaluated that the multi-core cable suppresses the generation of noise during twisting.

[0156] (Experimental conditions and results)

[0157] Hereinafter, the multi-core cable in each experimental example will be described.

[0158] The following multi-core cables were produced: Experimental Example 1 and Experimental Example 2. Experimental Example 1 is a comparative example, and Experimental Example 2 is an example.

[0159] [Experimental Example 1]

[0160] Produce a Figure 1 The multi-core cable 10 has a structure of a cross section perpendicular to the longitudinal direction shown.

[0161] like Figure 1 As shown, in a cross section perpendicular to the longitudinal direction of the multi-core cable 10, a plurality of covered electric wires 20 are arranged to form two layers of a first layer 111 and a second layer 112 from the center of the core 11, and the plurality of covered electric wires 20 are twisted. Furthermore, the plurality of covered electric wires 20 arranged on the outer surface of the core 11 are arranged along the circumscribed circle C11 of the core 11. The respective covered electric wires 20 of the core 11 have been described, and therefore the description thereof is omitted.

[0162] In addition to the core 11 , a crimp 14 , a shield layer 12 , and a sheath 13 are arranged in this order from the position close to the core 11 .

[0163] The configuration of the braided conductor 200 of the shield layer 12 is shown in the “Braid” column of Table 1.

[0164] Table 1 shows the evaluation results.

[0165] [Experimental Example 2]

[0166] The outer diameter D21 of the metal wire used for the shield 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.

[0167] Table 1 shows the evaluation results.

[0168] [Table 1]

[0169]

Claims

1. A multi-core cable having: The core is formed by twisting a number of covered wires; A skin, disposed outside the core; as well as A shielding layer is disposed between the core and the sheath, The shielding layer has a braided conductor formed by braiding metal wires. The outer diameter of the metal wire is not less than 0.05 mm and not more than 0.08 mm, The braiding density of the braided conductor is 91% or more, and the braiding pitch of the braided conductor is 5 times or more and 6 times or less of the outer diameter of the core.

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

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