cable

Abstract

To provide a cable having bending resistance.SOLUTION: A cable comprising a core including a coated wire and an outer sheath disposed outside the core, wherein the coated wire includes a conductor formed of a copper alloy and an insulator disposed outside the conductor, the conductor is a stranded wire obtained by twisting a plurality of conductor wires, a twist pitch of the conductor is 25 times or less of an outer diameter of the conductor, and the insulator contains a polyvinyl chloride resin and has a tensile modulus of elasticity of 150 MPa or more.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] Patent Document 1 describes a wire harness comprising a plurality of twisted insulated wires each having a conductor and an insulating layer covering the outer periphery of the conductor, a plurality of interposers contacting the insulating layers of the plurality of insulated wires; Equipped with A lubricant is applied to each of the plurality of intervening portions, A multi-core cable is disclosed in which the absolute value of the difference between the SP value of the material forming the multiple intervening layers and the SP value of the lubricant is smaller than the absolute value of the difference between the SP value of the lubricant and the SP value of the material forming the insulating layer. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-113276 Summary of the Invention [Problem to be solved by the invention]

[0004] Cables used in factories and the like are often arranged in drive units and are repeatedly bent, so that cables used in factories and the like are required to have bending resistance.

[0005] Therefore, an object of the present disclosure is to provide a cable that is resistant to bending. [Means for solving the problem]

[0006] The cable of the present disclosure has a core including a coated electric wire and an outer sheath arranged on the outside of the core, the coated electric wire has a conductor formed from a copper alloy and an insulator arranged on the outside of the conductor, the conductor is a twisted wire formed by twisting together multiple conductor wires, the twist pitch of the conductor is 25 times or less the outer diameter of the conductor, and the insulator contains polyvinyl chloride resin and has a tensile modulus of elasticity of 150 MPa or more. [Effects of the Invention]

[0007] According to the present disclosure, a cable with bending resistance can be provided. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a cross-sectional view of a cable according to one embodiment of the present disclosure taken along a plane perpendicular to the longitudinal direction thereof. [Figure 2] FIG. 2 is a cross-sectional view of a cable according to another embodiment of the present disclosure taken along a plane perpendicular to the longitudinal direction thereof. [Figure 3] FIG. 3 is a cross-sectional view of a cable according to another embodiment of the present disclosure taken along a plane perpendicular to the longitudinal direction thereof. [Figure 4] FIG. 4 is a cross-sectional view of a cable according to another embodiment of the present disclosure taken along a plane perpendicular to the longitudinal direction thereof. [Figure 5] FIG. 5 is an explanatory diagram of a method for evaluating bending resistance. [Figure 6] FIG. 6 is a table showing the configuration and evaluation results of the experimental example. DETAILED DESCRIPTION OF THE INVENTION

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

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

[0011] (1) A cable according to one embodiment of the present disclosure has a core including a coated electric wire and an outer sheath arranged outside the core, the coated electric wire has a conductor formed from a copper alloy and an insulator arranged outside the conductor, the conductor is a twisted wire formed by twisting together a plurality of conductor wires, the twist pitch of the conductor is 25 times or less the outer diameter of the conductor, and the insulator contains polyvinyl chloride resin and has a tensile modulus of elasticity of 150 MPa or more.

[0012] The conductor of the coated electric wire in the cable according to one embodiment of the present disclosure is formed from a copper alloy, which increases the strength of the conductor and makes it less likely to break compared to when the conductor is formed from soft copper.

[0013] By setting the twist pitch of the conductor to 25 times or less the outer diameter of the conductor, it is possible to stabilize the behavior of the position of the insulated wire in the cable when the cable is bent, and to prevent large localized loads from being applied to the conductor.

[0014] The insulator contains polyvinyl chloride resin, which makes it easy to adjust the tensile modulus of the insulator to a desired range. By making the insulator's tensile modulus 150 MPa or more, the behavior of the insulated wire in the cable, which changes position when the cable is bent, can be stabilized, and large local loads on the conductor can be prevented.

[0015] Therefore, according to a cable according to one aspect of the present disclosure, even when the cable is repeatedly bent, the conductor contained in the coated wire of the cable can be prevented from breaking, thereby improving the bending resistance of the cable.

[0016] (2) In the above (1), the core may include a plurality of the insulated electric wires, and the plurality of insulated electric wires may be twisted together along the length.

[0017] Since the core contains multiple coated wires, it is possible to connect multiple terminals with a single cable, improving wiring workability.

[0018] By twisting multiple insulated electric wires together, the multiple insulated electric wires can be handled as a single unit, which increases the productivity of the cable and also improves adhesion to the outer sheath.

[0019] (3) In the above (1) or (2), a shielding layer may be disposed between the core and the jacket.

[0020] The shielding layer in the cable can reduce signal leakage to the outside and signal intrusion from the outside, and also provides mechanical protection for the core.

[0021] (4) In any of the above (1) to (3), the copper alloy may be a copper-tin alloy.

[0022] By using a copper-tin alloy as the copper alloy for the conductor, it is possible to increase electrical conductivity and reduce costs.

[0023] (5) In any one of the above (1) to (4), the outer covering may contain polyvinyl chloride resin.

[0024] Polyvinyl chloride resin is a resin with excellent flame retardancy, so if the outer jacket contains polyvinyl chloride resin, the flame retardancy of the cable can be improved.

[0025] (6) In any one of the above (1) to (5), the outer covering may contain a flame retardant.

[0026] The flame retardancy of the cable can be improved by including a flame retardant in the outer sheath.

[0027] (7) In any one of the above (1) to (6), the core may include a twisted pair electric wire formed by twisting two of the covered electric wires together.

[0028] By twisting two covered electric wires together to form a twisted pair electric wire, the signals transmitted by the covered electric wire can be made less susceptible to the effects of noise.

[0029] (8) In any of the above (1) to (7), the core may include an inclusion.

[0030] The inclusion of the core prevents displacement of the insulated wires contained in the cable when the cable is repeatedly bent, improving bending resistance. In addition, the shape of the core outline can be made closer to a circle in a cross section perpendicular to the longitudinal direction of the cable, improving the handleability of the cable.

[0031] [Details of the embodiments of the present disclosure] Specific examples of cables 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 of the claims. [cable] Fig. 1 shows a schematic diagram of a cross section perpendicular to the length of the cable of this embodiment. Figs. 2, 3, and 4 show schematic diagrams of cross sections perpendicular to the length of cables according to other configuration examples of this embodiment. In Figs. 1, 2, 3, and 4, the length of the cable is along the Z axis, i.e., the axis perpendicular to the paper surface. Figs. 1, 2, 3, and 4 show cross sections on the XY plane perpendicular to the Z axis.

[0032] 2, 3, and 4 are explanatory diagrams of other configuration examples of the cable of this embodiment, and therefore, the following description will be given mainly using FIG. 1, and will also use FIGS. 2 and 3 as necessary.

[0033] As shown in FIG. 1, a cable 10 of this embodiment has a core 100 including a coated wire 11 and an outer jacket 12 disposed outside the core 100. (1) Regarding the components contained in the cable Each member contained in the cable of this embodiment will be described. (1-1) Core As shown in FIG. 1, the core 100 can include a covered wire 11 .

[0034] The number of coated wires 11 in the core 100 is not particularly limited.

[0035] The core 100 may include only one covered electric wire 11. Alternatively, like the covered electric wire 11 shown in Fig. 1, the core 100 may include two or more covered electric wires 11. When the core 100 includes multiple covered electric wires 11, the cable 10 of this embodiment may also be referred to as a multi-core cable.

[0036] By including a plurality of coated electric wires 11 in the core 100, it becomes possible to connect a plurality of terminals with a single cable, thereby improving the workability of wiring.

[0037] When the core 100 includes a plurality of insulated electric wires 11, the plurality of insulated electric wires 11 may be twisted together along the longitudinal direction. By twisting the plurality of insulated electric wires 11 together, the plurality of insulated electric wires 11 can be handled as a single unit, thereby improving the productivity of the cable 10 and also improving the adhesion with the jacket 12.

[0038] There is no particular limitation on the twist pitch of the core 100, i.e., the twist pitch when twisting the coated electric wires 11 included in the core 100. The twist pitch of the core 100 may be, for example, 5 to 20 times the outer diameter D100 of the core 100.

[0039] By setting the twist pitch of the core 100 to 20 times or less the outer diameter D100 of the core 100, the position of the coated wire 11 included in the core 100 is less likely to change even when the cable 10 is repeatedly bent, thereby improving bending resistance.

[0040] By setting the twist pitch of the core 100 to be five times or more the outer diameter D100 of the core 100, the productivity of the core 100 and the cable can be increased.

[0041] The outer diameter D100 of the core 100 can be the average value of the lengths of two perpendicular diameters in the smallest encompassing circle C100 of the core 100. In this specification, bending resistance means the property of the coated wire 11 included in the cable 10 not easily breaking when the cable 10 is repeatedly bent.

[0042] Although Fig. 1 shows an example in which the core 100 includes eight covered electric wires 11, the present invention is not limited to this. For example, as in the cable 30 shown in Fig. 3, the core 300 may include 16 covered electric wires 11, and as in the cable 40 shown in Fig. 4, the core 400 may include 24 covered electric wires 11. However, the cable is not limited to the cable configurations shown in Figs. 1, 3, and 4, and the cable of this embodiment may include any number of covered electric wires 11 depending on the application, etc. Furthermore, the covered electric wires 11 contained in the cable of this embodiment are not limited to those having the same size and material for the conductor and insulator, and may include covered electric wires 11 of different sizes and materials.

[0043] 3 and 4, the reference numerals of some of the insulated electric wires 11 and the reference numerals of the conductors 111 and insulators 112 that form the insulated electric wires 11 are omitted, but the double-circle-shaped objects in the figures are insulated electric wires 11. As will be described with reference to FIG. 1, each insulated electric wire 11 has a conductor 111 and an insulator 112.

[0044] As shown in Fig. 1, the core 100 may include a twisted pair electric wire 101 formed by twisting together two covered electric wires 11. For example, as in the core 400 shown in Fig. 4, the core 100 may include a plurality of pairs of twisted pair electric wires 101. Some or all of the covered electric wires 11 included in the core 100 may be twisted pair electric wires.

[0045] The twisted pair electric wire 101 can be further twisted with another coated electric wire 11 or another twisted pair electric wire 101 to form a core 100.

[0046] By twisting two covered electric wires together to form a twisted pair electric wire, the signals transmitted by the covered electric wire can be made less susceptible to the effects of noise. (1-2) Insulated wire The coated wire 11 has a conductor 111 made of a copper alloy and an insulator 112 disposed on the outside of the conductor 111 . (1-2-1) Conductor The inventors of the present invention have conducted research into cables with excellent flex resistance. As a result, they have found that flex resistance can be improved by forming conductor 111 from a copper alloy. This is because forming conductor 111 from a copper alloy increases the strength of conductor 111 and makes it less likely to break compared to when it is formed from soft copper.

[0047] The copper alloy used for the conductor 111 may be one or more selected from a copper-silver alloy, a copper-tin alloy, a copper-zirconium alloy, and a copper-beryllium alloy. The copper alloy used for the conductor 111 may be a copper-tin alloy. By using a copper-tin alloy as the copper alloy for the conductor 111, it is possible to improve electrical conductivity and reduce costs.

[0048] The tin content in the copper-tin alloy is not particularly limited, but may be, for example, 0.1% by mass or more and 1.7% by mass or less. When the copper-tin alloy contains 0.1% by mass or more of tin, the strength of the conductor 111 can be increased. Furthermore, when the copper-tin alloy contains 1.7% by mass or less of tin, the electrical conductivity of the conductor 111 can be increased.

[0049] The conductor 111 can be a stranded wire made by twisting together a plurality of conductor wires 111A. In Fig. 1, only the conductor wire 111 included in one covered electric wire 11 is shown as a conductor wire 111A, but even in a covered electric wire 11 where the conductor is shown as a single circle, the conductor can be a stranded wire made by twisting together conductor wires. The same applies to the cables shown in Figs. 2 to 4.

[0050] The twist pitch of the conductor 111, that is, the twist pitch when twisting the conductor wires 111A, can be 25 times or less the outer diameter D111 of the conductor 111, and may be 18 times or less the outer diameter D111 of the conductor 111.

[0051] By setting the twist pitch of the conductor 111 to 25 times or less the outer diameter D111 of the conductor 111, it is possible to stabilize the behavior of the positional change of the insulated wire 11 of the cable 10 when the cable 10 is bent, thereby preventing a large load from being applied locally to the conductor 111.

[0052] The lower limit of the twist pitch of the conductor 111 is not particularly limited, but may be, for example, 10 times or more, or 15 times or more the outer diameter D111 of the conductor 111.

[0053] Therefore, the twist pitch of the conductor 111 may be, for example, 10 times or more and 25 times or less, or 15 times or more and 18 times or less, of the outer diameter D111 of the conductor 111.

[0054] The cross-sectional area of ​​the conductor 111 is not particularly limited, but for example, 2 More than 3mm 2 It may be the following:

[0055] The cross-sectional area of ​​the conductor 111 is 0.05 mm 2 By setting the cross-sectional area of ​​the conductor 111 to 3 mm or more, the electrical resistance value of the conductor can be reduced. 2 By setting the following, the weight of the coated electric wire 11 can be reduced.

[0056] The cross-sectional area of ​​the conductor 111 is calculated by multiplying the cross-sectional area of ​​the conductor wires 111A, which is calculated from the wire diameter of the conductor wires 111A, by the number of conductor wires 111A that the conductor 111 has. (1-2-2) Insulator As shown in FIG. 1, the insulator 112 can cover the outer surface of the conductor 111, specifically the outer surface along the longitudinal direction of the covered electric wire 11. (Ingredients contained in the insulator) The insulator 112 may contain a resin.

[0057] The insulator 112 may contain polyvinyl chloride resin. When the insulator 112 contains polyvinyl chloride resin, the tensile modulus of the insulator 112 can be easily adjusted to fall within a desired range.

[0058] The resin may or may not be crosslinked.

[0059] In addition to resin, the insulator 112 may contain one or more additives selected from a flame retardant, a flame retardant assistant, an antioxidant, a lubricant, a colorant, a reflectivity imparting agent, an opacifying agent, a processing stabilizer, and a plasticizer.

[0060] As will be described later, the insulator 112 may have a tensile modulus of elasticity of 150 MPa or greater.

[0061] In order to make the tensile modulus of the insulator 112 150 MPa or more, the insulator 112 may contain an additive, for example, a plasticizer. As the plasticizer, a plasticizer that can be applied to the polyvinyl chloride contained in the insulator 112 can be used. As the plasticizer, for example, one or more types selected from phthalate ester-based plasticizers such as diisononyl phthalate (DINP) and dioctyl phthalate (DINP), trimellitate ester-based plasticizers such as tris(2-ethylhexyl) trimellitate (TOTM), polyester-based plasticizers, etc. can be used.

[0062] The content of the plasticizer in the insulator 112 is not particularly limited, and can be selected depending on the type of plasticizer so that the tensile modulus of the insulator 112 has a desired value. (Tensile modulus of insulator) The insulator 112 may have a tensile modulus of elasticity of 150 MPa or more.

[0063] By setting the tensile modulus of the insulator 112 to 150 MPa or more, it is possible to stabilize the behavior of the positional change of the insulated electric wire 11 of the cable 10 when the cable 10 is bent. In other words, when the cable 10 is repeatedly bent, the change in the position of the insulated electric wire 11 does not become irregular, but can be made small and regular. Therefore, it is possible to prevent a large load from being applied locally to the conductor 111 when the cable 10 is bent.

[0064] The upper limit of the tensile modulus of the insulator 112 is not particularly limited, but may be, for example, 600 MPa or less. Therefore, the tensile modulus of the insulator 112 may be 150 MPa or more and 600 MPa or less.

[0065] The tensile modulus of elasticity of the insulator 112 can be adjusted by, for example, the blending ratio of the plasticizer contained in the insulator 112 . (1-3) Outer covering As shown in FIG. 1, the cable 10 may further include a jacket 12 disposed outside the core 100 .

[0066] The cable 10 has the outer sheath 12, which protects the coated wire 11 contained in the core 100 disposed inside, and improves durability. (resin) The outer jacket 12 may contain a resin. The resin is not particularly limited, but the outer jacket 12 may contain, for example, one or more types selected from polyvinyl chloride resin and polyolefin resin, or may contain polyvinyl chloride resin.

[0067] By including one or more types of resin selected from polyvinyl chloride resin and polyolefin resin in the outer sheath 12, the insulated wire 11 of the cable 10 can be protected while reducing costs compared to when a fluororesin or the like is used as the resin.

[0068] Polyvinyl chloride resin is a resin with excellent flame retardancy, so if the jacket 12 contains polyvinyl chloride resin, the flame retardancy of the cable 10 can also be improved.

[0069] The resin of the jacket 12 may or may not be crosslinked. (additives) In addition to the above resins, the jacket 12 may contain additives such as flame retardants, flame retardant assistants, antioxidants, lubricants, colorants, reflectivity imparting agents, opacifying agents, processing stabilizers, and plasticizers.

[0070] The jacket 12 may contain a flame retardant to enhance the flame retardancy of the cable 10. The flame retardant is not particularly limited, but may be one or more selected from the group consisting of magnesium hydroxide, aluminum hydroxide, antimony trioxide, and bromine-based flame retardants.

[0071] By including a flame retardant in the jacket 12, the flame retardancy of the cable 10 can be improved. (1-4) Shield layer Like the cable 20 shown in FIG. 2, the cable 20 may have a shielding layer 14 disposed between the core 200 and the jacket 12 .

[0072] The shield layer 14 may include a conductive material. (Conductive tape) The shielding layer 14 may include a conductive tape.

[0073] The shield layer 14 may be formed, for example, by spirally winding a conductive tape including a conductive layer along the length of the core 200 .

[0074] The conductive tape may have only a conductive layer, or may have a laminated structure in which a conductive layer is disposed on one or more surfaces selected from the upper and lower surfaces of a substrate.

[0075] The material of the conductive layer is not particularly limited, but may contain a metal, for example, metal foil. When the conductive layer contains a metal, the metal material is not particularly limited, but may be one or more selected from copper, copper alloys, aluminum, aluminum alloys, etc.

[0076] The material of the substrate is not particularly limited, but may contain one or more selected from insulating materials such as organic polymer materials and nonwoven fabrics. Examples of organic polymer materials include polyester resins such as polyethylene terephthalate (PET), polyolefin resins such as polypropylene, and vinyl resins such as polyvinyl chloride. The substrate may contain an insulating material, or may be made of only an insulating material.

[0077] When the shield layer 14 is formed by winding a conductive tape, the winding direction of the conductive tape is not particularly limited, and may be the same as or different from the twisting direction of the core 200, for example. (metal wire) The shield layer 14 may include metal wires.

[0078] When shielding layer 14 includes metal wires, the metal wires may be arranged in a braided structure or a spirally wound structure in shielding layer 14. By including metal wires in shielding layer 14 and having a braided structure or a spirally wound structure, breakage of shielding layer 14 can be prevented even when cable 10 is repeatedly bent.

[0079] The metal wires may be made of one or more materials selected from copper, aluminum, copper alloys, etc. The surfaces of the metal wires may be plated with silver or tin. Therefore, the metal wires may be made of, for example, a silver-plated copper alloy or a tin-plated copper alloy.

[0080] The cable has a shielding layer, which increases the cable's bending resistance and reduces signal leakage to the outside and signal intrusion from the outside. The shielding layer also provides mechanical protection for the core.

[0081] When the cable 20 has the shielding layer 14, the cable 20 may also have a drain wire 15 so as to enable electrical connection between the ground terminal of the device connected to the end of the cable 20 and the shielding layer 14. In the cable 20, the drain wire 15 may be disposed within the core 200 so as to be electrically connected to the shielding layer 14. The drain wire 15 may be twisted with the covered wire 11.

[0082] Drain wire 15 may have the same configuration as covered wire 11, except that it does not have insulator 112 and conductor 111 is exposed. Therefore, the same material as that of conductor 111 may be used for drain wire 15. The conductor of drain wire 15 may be a solid wire or a stranded wire in which multiple conductor wires are twisted together. (1-5) Intervention The core 100 of the cable 10 of this embodiment may include fillers 13 .

[0083] Including the filler 13 in the core 100 prevents displacement of the position of the coated wire 11 included in the cable 10 when the cable 10 is repeatedly bent, thereby improving the bending resistance. Also, in a cross section perpendicular to the longitudinal direction of the cable 10, the shape of the outline of the core 100 can be made closer to a circle, improving the handleability of the cable 10.

[0084] The filler 13 may be arranged, for example, in a cross section perpendicular to the longitudinal direction of the cable 10 so that the shape of the outline of the core 100 approaches a circle. For this reason, the filler 13 may be arranged in an area surrounded by the covered electric wires 11, as in the cable 10 shown in FIG. 1, or may be arranged at any multiple locations within the core 100 in a cross section perpendicular to the longitudinal direction of the cable 10.

[0085] The filler may include fibers such as staple fibers or nylon fibers. The filler may also include tensile strength fibers. (1-6) Pressing The cable 10 may also have a pressure wrap between the core 100 and the jacket 12. The pressure wrap may be formed, for example, by winding a tape body in a spiral shape along the longitudinal direction of the core 100. When the pressure wrap is formed by winding a tape body around the outer periphery of the core 100, the winding direction of the tape body is not particularly limited, and may be, for example, the same as or different from the twisting direction of the core 100 described above.

[0086] The tape body may include an insulating material such as paper, nonwoven fabric, or resin such as polyester.

[0087] By disposing a pressure winding between the core 100 and the jacket 12, the jacket 12 can be easily peeled off at the end along the length of the cable 10 when the coated wire 11 is taken out. [Example]

[0088] The present invention will be explained below by giving specific examples, but the present invention is not limited to these examples. 1. Evaluation Method First, the evaluation method of the electric wires produced in the following experimental examples will be described. (1) Wire diameter, outer diameter The wire diameter of the conductor wire 111A (see FIG. 1) used in the conductor 111 was determined by measuring the lengths of two perpendicular diameters in any cross section perpendicular to the longitudinal direction of the conductor wire 111A, and averaging the two diameters.

[0089] The outer diameter D111 of the conductor 111 was determined by measuring the lengths of two perpendicular diameters of the minimum including circle C111 of the conductor 111 in any cross section perpendicular to the longitudinal direction of the cable 10, and calculating the average value of the two diameters (see FIG. 1). The minimum including circle is the smallest circle that can contain the target shape. Therefore, the minimum including circle C111 of the conductor 111 is the smallest circle that can contain the conductor 111 in the cross section being evaluated.

[0090] The outer diameter D200 of the core 200 was determined by measuring the lengths of two perpendicular diameters in the minimum encompassing circle C200 of the core 200 in any cross section perpendicular to the longitudinal direction of the cable 20, and taking the average value of the two diameters. (2) Twist pitch To measure the twist pitch of the conductor 111 of the insulated electric wire 11, the insulator 112 of the insulated electric wire 11 was removed to expose the conductor 111. Next, the twist pitch of the conductor 111, i.e., the twist pitch when twisting the conductor wires 111A included in the conductor 111, was measured in accordance with JIS C 3005 (2014). Then, the ratio of the twist pitch of the conductor 111 to the outer diameter D111 of the conductor 111 was calculated.

[0091] The twist pitch of the core 200 was measured using the same procedure as for the twist pitch of the conductor 111, except that the measurement object was the core 200 and the twist pitch was the twist pitch when twisting the coated electric wires 11 included in the core 200. Then, the ratio of the twist pitch of the core 200 to the outer diameter D200 of the core 200 was calculated. (3) Tensile elasticity test The insulator 112 of the coated electric wire 11 was subjected to a tensile test in accordance with JIS K 7161 (2024) at a tensile speed of 500 mm / min and a gauge length of 50 mm using a tensile tester. (4) Flexibility The bending resistance test was carried out according to the following procedure.

[0092] As shown in FIG. 5 , a cable 50 to be evaluated was placed vertically between two 40 mm diameter mandrels, a first mandrel 511 and a second mandrel 512, which were arranged horizontally and parallel to each other. The upper end of the cable 50 was then bent horizontally by 90° so that it abutted against the upper side of the first mandrel 511, and then bent horizontally by 90° so that it abutted against the upper side of the second mandrel 512. This repetition was performed while connecting all the conductors of the insulated wires in the cable in series and measuring the resistance. The number of bends at which the resistance increased to more than 10 times the initial resistance before the test was used as an index value for the flex endurance test. The number of bends evaluated in the flex endurance test was defined as one bend, where the cable 50 was bent from the left side in FIG. 5 to the right side and then returned to the left side. During the flex endurance test, a downward load of 5 N was applied to the cable 50 along the block arrow 52 in FIG. 5 .

[0093] Three samples were prepared for the same experimental example and evaluated, and the smallest number of flexing cycles among the three samples was taken as the number of flexing cycles in the flex resistance test for the sample of that experimental example.

[0094] The index values ​​of the flex resistance test, that is, the number of flexes was 1 million or more, was evaluated as A, the number of flexes was 500,000 or more but less than 1 million, was evaluated as B, the number of flexes was 250,000 or more but less than 500,000, was evaluated as C, and the number of flexes was less than 250,000, was evaluated as D. The evaluation results are shown in the "Flex resistance" column in Table 1.

[0095] A cable that receives an A rating in the bending resistance test can be said to have the best bending resistance, with bending resistance decreasing in the order of B, C, and D. A cable that receives an A or B rating in the bending resistance test can be evaluated as having sufficient bending resistance. A cable that receives an C or D rating in the bending resistance test can be evaluated as not having sufficient bending resistance.

[0096] When making the overall evaluation, a rating of A was given 2 points, a rating of B was given 1 point, a rating of C was given -1 point, and a rating of D was given -2 points. (5) Flame retardancy The flame retardancy test was carried out using the vertical flame test (VW-1) specified by the UL standard.

[0097] The vertical flame test (VW-1) is described in UL Standard 2556, and the following evaluations were carried out on three samples prepared under the same conditions.

[0098] Each sample was placed with the cable length vertical, and a burner flame was applied for 15 seconds, followed by a 15-second flame removal cycle, repeated five times. After five cycles of flame application and removal, a sample was deemed good if it extinguished within 60 seconds, the absorbent cotton underneath was not ignited by falling flames, and the kraft paper attached to the top of the sample was not burned or scorched. Three samples were then evaluated; if all three were good, they were rated A; if one or two were not good, they were rated B; and if none of the three were good, they were rated C. The evaluation results are shown in the "Flame Retardance" column in Table 1.

[0099] A rating of A indicates a cable with excellent flame retardancy, while a rating of B or C indicates a cable with poor flame retardancy.

[0100] When making the overall evaluation, a rating of A was given 2 points, a rating of B was given 1 point, and a rating of C was given 0 points. (6) Bending resistance of the shielding layer After the flex resistance test was completed, the outer jacket 12 was removed and the condition of the shielding layer 14 was visually inspected. If no breaks were found in the metal wires or metal foil contained in the shielding layer 14, it was rated as A, and if the metal wires or metal foil contained in the shielding layer 14 were broken and contained discontinuous portions, it was rated as B. The evaluation results are shown in the "Flex resistance of shield" column in Table 1.

[0101] A rating of A indicates a cable with excellent shielding resistance, while a rating of B indicates a cable with poor shielding resistance.

[0102] When making the overall evaluation, an A rating was given 2 points and a B rating was given 0 points. (7) Overall rating Scores based on the evaluation of flex resistance, flame retardancy, and flex resistance of the shielding layer were added together.

[0103] If the overall rating is 2 or higher, the cable can be rated as excellent overall. 2. Cable manufacturing conditions The cables used in each experiment are described below.

[0104] Experimental Examples 1 to 7 are working examples, and Experimental Examples 8 to 15 are comparative examples. (Experimental Example 1) A cable 20 having the cross-sectional structure shown in FIG. 2 was produced and evaluated. (1) Insulated wire The conductor 111 of the insulated electric wire 11 of the cable 20 is made by twisting together 40 strands of wires each having a wire diameter of 0.08 mm, and the conductor cross-sectional area is 0.20 mm. 2 A copper-tin alloy containing 0.3 mass % of tin is used as the material for the conductor 111. When the copper-tin alloy is used as the material for the conductor 111, it is referred to as a "copper alloy" in Table 1.

[0105] As shown in the "Twist Pitch" column in Table 1, the twist pitch of the conductor 111 was 21 times the outer diameter D111 of the conductor 111.

[0106] As shown in the "Resin" column in Table 1, the insulator 112 is made of a material that contains polyvinyl chloride resin (PVC) as the resin and has the tensile modulus shown in Table 1.

[0107] Two of the coated electric wires 11 were twisted together to form a twisted pair electric wire 101, which was then twisted together with other coated electric wires 11 and drain wires 15 to form a core 200. The twist pitch of the core 200 was about 10 times the outer diameter D200 of the core 200.

[0108] Outside the core 200, a shield layer 14 and an outer jacket 12 are arranged in this order from the position closest to the core 200. (2) Shield layer The shielding layer was formed by using a conductive tape with aluminum foil arranged on a polyethylene terephthalate (PET) substrate and spirally wrapping it along the longitudinal direction of the core 200. In Table 1, this shielding layer is referred to as "Al metal foil." (3) Outer covering As shown in the "Resin" column in Table 1, the outer jacket 12 contains polyvinyl chloride resin as the resin. A material containing a flame retardant is used for the outer jacket 12. If the outer jacket 12 contains a flame retardant, the "Flame Retardant" column in Table 1 will be marked with "Yes."

[0109] The evaluation results are shown in Table 1. (Experimental Example 2) Cables were produced and evaluated under the same conditions as in Experimental Example 1, except that the amount of plasticizer added to insulator 112 was changed to give the tensile modulus of elasticity shown in Table 1. The evaluation results are shown in Table 1. (Experimental Example 3) A cable was produced and evaluated under the same conditions as in Experimental Example 2, except that shielding layer 14 was a braided shielding layer made of metal wires formed from the same copper alloy as conductor 111.

[0110] Such a shielding layer is referred to as "metal wire" in Table 1. The evaluation results are shown in Table 1. (Experimental Example 4) Aside from changing the twist pitch of conductor 111, a cable was produced and evaluated under the same conditions as in Experimental Example 2. The evaluation results are shown in Table 1. (Experimental Example 5) A cable was produced and evaluated under the same conditions as in Experimental Example 4, except that shielding layer 14 was a braided shielding layer made of metal wires formed from the same copper alloy as conductor 111. (Experimental Example 6) Aside from changing the twist pitch of conductor 111, a cable was produced and evaluated under the same conditions as in Experimental Example 2. The evaluation results are shown in Table 1. (Experimental Example 7) A cable was produced and evaluated under the same conditions as in Experimental Example 2, except that polyethylene resin (PE) was used instead of polyvinyl chloride as the resin for the jacket 12. The evaluation results are shown in Table 1. (Experimental Example 8) The amount of plasticizer added to the insulator 112 was changed to obtain the tensile modulus shown in Table 1. In addition, no flame retardant was added to the jacket 12. Except for the above points, cables were produced and evaluated under the same conditions as in Experimental Example 1. The evaluation results are shown in Table 1.

[0111] If the outer jacket 12 does not contain a flame retardant, the "Flame Retardant" column in Table 1 is marked with "-". (Experimental Example 9) Cables were produced and evaluated under the same conditions as in Experimental Example 1, except that the amount of plasticizer added to insulator 112 was changed to give the tensile modulus of elasticity shown in Table 1. The evaluation results are shown in Table 1. (Experimental Example 10) Cables were produced and evaluated under the same conditions as in Experimental Example 1, except that the amount of plasticizer added to insulator 112 was changed to give the tensile modulus of elasticity shown in Table 1. The evaluation results are shown in Table 1. (Experimental Example 11) Aside from changing the twist pitch of conductor 111, a cable was produced and evaluated under the same conditions as in Experimental Example 2. The evaluation results are shown in Table 1. (Experimental Example 12) Annealed copper was used as the material for conductor 111, and the twist pitch of conductor 111 was 18 times the outer diameter D111 of conductor 111. No flame retardant was added to outer jacket 12. Other than the above, a cable was produced and evaluated under the same conditions as in Experimental Example 2. The evaluation results are shown in Table 1. (Experimental Example 13) Annealed copper was used as the material for conductor 111, and the twist pitch of conductor 111 was 18 times the outer diameter D111 of conductor 111. Other than the above, a cable was produced and evaluated under the same conditions as in Experimental Example 2. The evaluation results are shown in Table 1. (Experimental Example 14) For the sheath 12, polyethylene resin (PE) was used instead of polyvinyl chloride as the resin. The amount of plasticizer added to the insulator 112 was changed to give the tensile modulus shown in Table 1. In addition, no flame retardant was added to the sheath 12. Apart from the above, a cable was produced and evaluated under the same conditions as in Experimental Example 1. The evaluation results are shown in Table 1. (Experimental Example 15) Polyethylene resin (PE) was used instead of polyvinyl chloride as the resin for the jacket 12. The amount of plasticizer added to the insulator 112 was changed to give the tensile modulus shown in Table 1. Except for the above points, a cable was produced and evaluated under the same conditions as in Experimental Example 1. The evaluation results are shown in Table 1.

[0112] According to the results shown in Table 1, it was confirmed that the cables of Experimental Examples 1 to 7, in which the twist pitch of conductor 111 is 25 times or less the outer diameter D111 of conductor 111, in which insulator 112 contains polyvinyl chloride, and in which the tensile modulus of elasticity is 150 MPa or more, have excellent bending resistance.

[0113] In contrast, in the cables of Experimental Examples 8 to 10, 14, and 15, the tensile modulus of insulator 112 was less than 150 MPa. In addition, in the cable of Experimental Example 11, the twist pitch of conductor 111 was greater than 25 times the outer diameter D111 of conductor 111. In addition, in the cables of Experimental Examples 12 and 13, annealed copper was used as the conductor material. For this reason, the cables of Experimental Examples 8 to 15 were evaluated as C or D in terms of bending resistance, confirming that they had poor bending resistance.

[0114] Furthermore, it was confirmed that the cables of Experimental Examples 8 to 15 had a lower overall rating than the cables of Experimental Examples 1 to 7. [Explanation of symbols]

[0115] 10 Cable 11. Insulated wire 111 Conductor 111A Conductor Wire 112 Insulator C111 Minimum enclosing circle 12 Outer cover 13 Intervention 101 Twisted pair wire 100 cores C100 Minimum enclosing circle D111 Conductor outer diameter D100 Core outer diameter 20 Cable 200 cores C200 Minimum Enclosing Circle D200 Core outer diameter 14 Shielding layer 15 Drain wire 30 Cable 300 cores 40 Cable 400 cores 50 Cable 52 Block Arrow 511 First Mandrel 512 Second Mandrel

Claims

1. a core including a coated wire; an outer jacket disposed outside the core; The coated wire has a conductor made of a copper alloy and an insulator disposed outside the conductor, the conductor is a stranded wire formed by twisting together a plurality of conductor wires, and the twist pitch of the conductor is 25 times or less the outer diameter of the conductor; A cable wherein the insulator contains polyvinyl chloride resin and has a tensile modulus of elasticity of 150 MPa or more.

2. The core includes a plurality of the coated wires, The cable according to claim 1 , wherein the plurality of coated wires are twisted together along their length.

3. 3. The cable of claim 1, further comprising a shielding layer disposed between the core and the jacket.

4. 3. The cable according to claim 1, wherein the copper alloy is a copper-tin alloy.

5. 3. The cable according to claim 1, wherein the outer jacket contains a polyvinyl chloride resin.

6. 3. The cable according to claim 1, wherein the jacket contains a flame retardant.

7. 3. The cable according to claim 1, wherein the core includes a twisted pair of wires formed by twisting two of the covered wires together.

8. 3. The cable of claim 1 or claim 2, wherein the core includes fillers.

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