cable

Abstract

We provide highly flexible cables. [Solution] A cable comprising a pair of twisted wires, an inner sheath placed outside the twisted wires, a shield layer placed outside the inner sheath, and an outer sheath placed outside the shield layer, wherein the repulsive force when bent into a U-shape and the radius of curvature of the bent portion is changed from 100 mm to 50 mm is 0.5 N or less.

Description

Technical Field

[0001] The present disclosure relates to a cable.

Background Art

[0002] Patent Document 1 discloses a twisted pair cable including a pair of mutually twisted electric wires, wherein the electric wires have a plurality of types of twisting pitches.

Prior Art Documents

Patent Documents

[0003] [[ID=2I]]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In recent years, the electrification of various vehicles such as automobiles has advanced, and the length of the cables installed inside the vehicle has become longer. The cable needs to be deformed according to the shape of the installation space, and is required to have excellent flexibility from the viewpoints of improving workability and productivity during the manufacture of automobiles and the like.

[0005] An object of the present disclosure is to provide a cable having excellent flexibility.

Means for Solving the Problems

Effects of the Invention

[0007] <000s040>​​​​According to this disclosure, it is possible to provide a cable with excellent flexibility. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a cross-sectional view of a cable according to one aspect of the present disclosure, in a plane perpendicular to the longitudinal side. [Figure 2A] Figure 2A is an explanatory diagram of the method for evaluating the rebound force. [Figure 2B] Figure 2B is an explanatory diagram of the method for evaluating the rebound force. [Figure 3] Figure 3 is an explanatory diagram of the method for evaluating the pull-out force. [Figure 4] Figure 4 is a table showing the configuration of the cable fabricated in the experimental example and the evaluation results. [Modes for carrying out the invention]

[0009] The implementation methods are described below.

[0010] [Description of Embodiments in this Disclosure] The embodiments of this disclosure are first listed and described. In the following description, the same or corresponding elements are denoted by the same reference numerals, and the same description of them is not repeated.

[0011] (1) A cable according to one aspect of the present disclosure comprises a pair of twisted wires, an inner sheath placed outside the pair of twisted wires, a shield layer placed outside the inner sheath, and an outer sheath placed outside the shield layer, wherein the repulsive force when bent into a U-shape and the radius of curvature of the bent portion is changed from 100 mm to 50 mm is 0.5 N or less.

[0012] By limiting the repulsive force to 0.5N or less, the cable becomes easily deformable and highly flexible, improving workability and productivity during wiring.

[0013] (2) In (1), the tensile elastic modulus of the inner sheath may be greater than that of the outer sheath and less than that of the insulator of the electric wire.

[0014] When a force is externally applied to the cable, the member farthest from the center will deform first. Therefore, regarding the tensile elastic modulus, by making the outer sheath farthest from the center of the cable the smallest and increasing it in the order of the inner sheath and the insulator, a cable that is particularly easily deformed and has excellent flexibility can be obtained.

[0015] (3) In (1) or (2), the inner sheath may contain polypropylene as a main component.

[0016] By including polypropylene as a main component in the inner sheath, the heat resistance of the cable can be enhanced, and the electrical characteristics can be improved even when heated.

[0017] (4) In (3), the inner sheath may further contain a thermoplastic elastomer as a main component.

[0018] By including a thermoplastic elastomer in the inner sheath, the flexibility of the inner sheath and the cable can be enhanced. Therefore, the repulsive force of the cable can be reduced, and the workability during wiring can be improved.

[0019] (5) In any one of (1) to (4), the insulator of the electric wire may contain polypropylene as a main component.

[0020] By including polypropylene as a main component in the insulator, the heat resistance of the electric wire, the twisted pair electric wire, and the cable can be enhanced, and the electrical characteristics can be improved even when heated.

[0021] (6) In any of (1) to (5), the shield layer may include a first shield layer containing a metal tape and a second shield layer containing a metal wire, and the pull-out force between the first shield layer and the second shield layer may be 10 N or more.

[0022] By having a first shielding layer and a second shielding layer in the cable, signal leakage to the outside and interference from external radio waves can be significantly reduced. Furthermore, the attenuation of the cable in the high-frequency range can be minimized.

[0023] By setting the pull-out force between the first shield layer and the second shield layer to 10N or more, the adhesion force at the shield layers is increased, preventing damage when force is applied along the length of the cable.

[0024] (7) In any of (1) to (6), there may be a further resin tape layer in which the resin tape is arranged spirally along the longitudinal direction of the twisted wire pair.

[0025] The cable of this disclosure, by further having a resin tape layer, can stabilize the shape of the twisted-pair wires. Therefore, in the cable of this disclosure, the shapes of the inner sheath, shield layer, and outer sheath, which are placed outside the twisted-pair wires, can also be stabilized, and they can be easily made into a desired shape.

[0026] [Details of the embodiments of this disclosure] A specific example of a cable according to one embodiment of this disclosure (hereinafter referred to as "this embodiment") will be described below with reference to the drawings. However, the present invention is not limited to these examples and is intended to be shown in the claims, with all modifications in the sense and scope equivalent to the claims being included.

[0027] In this specification, the names of components may be described with prefixes such as "1st shield layer" and "2nd shield layer." These prefixes are merely used to identify each component and prevent confusion during description; they do not indicate arrangement, priority, or anything else. Therefore, when there is no particular risk of confusion, or when referring to them collectively, they can simply be described as "shield layer."

[0028] Figures 1, 2A, 2B, and 3 are schematic diagrams illustrating the arrangement of each component and the procedures for evaluation methods, and do not accurately represent the size, shape, etc. of each component. [cable] Figure 1 shows a cross-sectional view of the cable 10 of this embodiment perpendicular to its longitudinal side.

[0029] In Figure 1, the axis along the length of the cable is defined as the Z-axis, and the plane perpendicular to the length of the cable 10 is defined as the XY plane.

[0030] As shown in Figure 1, the cable 10 of this embodiment includes a pair of twisted wires 110, an inner sheath 13 disposed outside the pair of twisted wires 110, a shield layer 14 disposed outside the inner sheath 13, and an outer sheath 15 disposed outside the shield layer 14.

[0031] The following describes each component of the cable 10 in this embodiment. (1) Regarding the components of the cable (1-1) Stranded wire A twisted-pair wire 110 is made by twisting together a pair of wires 11, that is, two wires 11. By twisting together a pair of wires 11 to form a twisted-pair wire 110, the flexibility of the cable 10 can be increased. (1-1-1) Electric wire The electric wire 11 has a conductor 111 and an insulator 112 placed outside the conductor 111. (conductor) The conductor 111 may be a single wire, a stranded wire made by twisting together multiple conductor strands 1111, or a compressed conductor made by compressing a stranded wire. By making the conductor 111 a stranded wire made by twisting together conductor strands 1111, the flexibility of the electric wire 11, the twisted pair electric wire 110, and even the cable 10 can be increased.

[0032] For the conductor 111, one or more conductive materials selected from, for example, copper, copper alloy, silver-plated copper, and tin-plated copper may be used. Soft copper may be used as the copper. Silver-plated copper and tin-plated copper may be silver-plated soft copper and tin-plated soft copper, respectively.

[0033] The cross-sectional area of ​​the conductor 111 is, for example, 0.05 mm². 2 More than 3mm 2 The following is also acceptable.

[0034] The cross-sectional area of ​​the conductor 111 can be determined from the measured wire diameter D1111 and the number of wires 1111 if the conductor 111 is a stranded wire. If the conductor 111 is a single wire, the cross-sectional area of ​​the conductor 111 can be determined from the measured outer diameter of the conductor 111. (Insulator) As shown in Figure 1, the insulator 112 can be placed outside the conductor 111 and can cover the outer surface along the longitudinal direction of the electric wire 11.

[0035] The insulator 112 may contain polyolefin resin.

[0036] Examples of polyolefin resins include polyethylene (PE), polypropylene (PP), ethylene-vinyl acetate copolymer (EVA), ethylene-ethyl acrylate copolymer (EEA), ethylene α-olefin copolymer, ethylene methyl acrylate copolymer, ethylene butyl acrylate copolymer, ethylene methyl methacrylate copolymer, ethylene acrylic acid copolymer, partially saponified EVA, maleic anhydride-modified polyolefin, ethylene acrylic acid ester maleic anhydride copolymer, and the like.

[0037] As the polyethylene, LLDPE (linear low-density polyethylene) or VLDPE (very low-density polyethylene) may be used.

[0038] The insulator 112 of the electric wire 11 may contain polypropylene as its main component.

[0039] By including polypropylene as the main component of the insulator 112, the heat resistance of the electric wire 11, the twisted wire pair 110, and the cable 10 can be improved, and the electrical properties can be enhanced even when heated.

[0040] The cable of this embodiment can be used as a signal line for transmitting signals at a communication speed of, for example, 1 Gbps or more. For this reason, the electrical characteristics in this specification mainly refer to the transmission characteristics when transmitting signals, and may be one or more characteristics selected from impedance, insertion loss (IL), reflection loss (RL), longitudinal conversion loss (LCL), and longitudinal transfer conversion loss (LCTL).

[0041] IL stands for Insertion Loss. RL stands for Return Loss. LCL stands for Longitudinal Conversion Loss. LCTL stands for Longitudinal Conversion Transfer Loss.

[0042] In this specification, "enhanced heat resistance and high electrical properties even when heated" means that the material passes the test when tested at 105°C, based on the SAE standard J3117-2. SAE is an abbreviation for Society of Automotive Engineers.

[0043] In this specification, the main component refers to the component in the resin (excluding additives such as flame retardants) that is present in an amount of 40% by mass or more. Note that the main component may contain multiple types of components.

[0044] The resin of the insulator 112 may or may not be crosslinked. The resin of the insulator 112 does not have to be crosslinked, and by making the resin of the insulator 112 non-crosslinked, the electrical characteristics of the electric wire 11, twisted pair electric wire 110, and cable 10 can be improved.

[0045] In addition to the resin mentioned above, the insulator 112 may also contain additives such as flame retardants, flame retardant enhancers, antioxidants, lubricants, colorants, reflective agents, opacifiers, processing stabilizers, and plasticizers. (1-2) Inner sheath The cable 10 in this embodiment may have an inner sheath 13 arranged outside the twisted wire pair 110.

[0046] By positioning the inner sheath 13 outside the twisted wire pair 110, the shape of the twisted wire pair 110 can be stabilized and protected.

[0047] The inner sheath 13 may contain polyolefin resin. An example of polyolefin resin was explained in the section on insulator 112, so the explanation is omitted here.

[0048] The inner sheath 13 may contain polypropylene as its main component.

[0049] By including polypropylene as the main component of the inner sheath 13, the heat resistance of the cable 10 can be increased, and its electrical properties can be improved even when heated.

[0050] The inner sheath 13 may further contain a thermoplastic elastomer, or may contain a thermoplastic elastomer as its main component.

[0051] The inclusion of a thermoplastic elastomer in the inner sheath 13 enhances the flexibility of both the inner sheath 13 and the cable 10. This reduces the repulsive force of the cable 10, improving workability during wiring.

[0052] Examples of thermoplastic elastomers include olefin-based elastomers, polyester-based elastomers, polyurethane-based elastomers, and polyamide-based elastomers. The thermoplastic elastomer may have a melting point of 160°C or higher. Using a thermoplastic elastomer with a melting point of 160°C or higher can improve the heat resistance of the cable 10.

[0053] The resin of the inner sheath 13 may or may not be crosslinked. The resin of the inner sheath 13 does not have to be crosslinked, and by making the resin of the inner sheath 13 non-crosslinked, the electrical characteristics of the cable 10 can be improved.

[0054] In addition to the resin mentioned above, the inner sheath 13 may also contain additives such as flame retardants, flame retardant enhancers, antioxidants, lubricants, colorants, reflective agents, opacifiers, processing stabilizers, and plasticizers. (1-3) Shield layer The cable 10 in this embodiment may have a shield layer 14 located outside the inner sheath 13.

[0055] The presence of a shielding layer 14 in cable 10 reduces signal leakage to the outside and interference from external radio waves. Furthermore, it reduces the attenuation of cable 10 in the high-frequency range.

[0056] The shield layer 14 may include a first shield layer 141 containing a metal tape and a second shield layer 142 containing a metal wire.

[0057] The cable 10 has a shield layer 14 consisting of a first shield layer 141 and a second shield layer 142, which significantly reduces signal leakage to the outside and radio wave intrusion from the outside. In addition, the attenuation of the cable 10 in the high-frequency range can be reduced.

[0058] Each shield layer will be explained below. (1-3-1) First Shield Layer The first shield layer 141 is a layer located outside the inner sheath 13, and may include a metal tape.

[0059] The metal tape may be arranged vertically, or it may be arranged spirally along the length of the inner sheath 13.

[0060] Vertical mounting refers to a method of arranging the metal tape so that its long side follows the long side of the inner sheath 13, and winding it so that the width of the metal tape follows the outer circumference of the inner sheath 13. When arranging the metal tape in a vertical manner, the ends of the metal tape may be arranged so that they overlap along the width of the tape.

[0061] When the metal tape is arranged spirally along the longitudinal side of the inner sheath 13, the metal tape may also be arranged spirally (horizontally) outside the inner sheath 13 so that at least a portion of it overlaps.

[0062] By placing the metal tape outside the thinner sheath 13 so that at least a portion of it overlaps, the outer surface of the inner sheath 13 can be completely covered with the metal tape, thereby improving the shielding characteristics.

[0063] The metal tape of the first shield layer 141 may have a metal layer containing a metal material. Examples of metal materials include one or more selected from copper, copper alloys, aluminum, aluminum alloys, etc. The metal layer of the metal tape may consist of only one layer of a single metal material, or it may consist of layers of two or more different metal materials. Furthermore, a non-metallic material, such as a protective film containing an organic material, may be placed on the surface of the metal layer.

[0064] The metal tape may further contain a base material. The base material may include insulating materials such as organic polymer materials or 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.

[0065] If the metal tape includes a substrate, the metal layer may be placed on one or more surfaces selected from the top and bottom surfaces of the substrate. (1-3-2) Second Shield Layer The second shield layer 142 is a layer containing metal wires.

[0066] As the material for the metal wire, metal materials such as copper, copper alloys, aluminum, aluminum alloys, etc., or materials with plating applied to their surface, such as tin-plated soft copper or silver-plated soft copper, may be used. Soft copper may be used as the copper.

[0067] The multiple metal strands in the second shield layer 142 may form a winding shield or a braided shield.

[0068] As described above, the second shield layer 142 may form a braided shield. By making the second shield layer 142 a braided shield, the gaps between the metal strands can be reduced, thereby improving the radio wave shielding characteristics of the shield layer 14. In addition, by making the second shield layer 142 a braided shield, damage to the second shield layer 142 can be prevented even when the cable 10 is repeatedly bent, thereby increasing durability. (1-4) Outer sheath The outer sheath 15 can be positioned outside the shield layer 14.

[0069] In this embodiment, the cable 10 includes an outer sheath 15, which protects the shield layer 14 and the twisted wire pair 110, preventing damage and other issues.

[0070] The outer sheath 15 may contain a resin material.

[0071] Examples of resin materials include one or more selected from polyolefin resin, polyester resin, polyvinyl chloride resin (PVC), fluororesin, etc.

[0072] An example of polyolefin resin was explained in the section on insulator 112, so the explanation will be omitted here.

[0073] Examples of polyester resins include polyethylene terephthalate (PET).

[0074] Examples of fluororesins include polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), and ethylene-tetrafluoroethylene copolymer (ETFE).

[0075] The resin material of the outer sheath 15 may or may not be cross-linked.

[0076] As mentioned above, the resin material of the outer sheath 15 does not have to be crosslinked. By making the resin material of the outer sheath 15 non-crosslinked, the resin material of the inner sheath 13 can also be non-crosslinked, thereby improving the electrical characteristics of the electric wire 11, the twisted pair electric wire 110, and the cable 10.

[0077] The outer sheath 15 may contain additives other than resin materials, such as flame retardants, flame retardant enhancers, antioxidants, lubricants, colorants, reflective agents, opacifiers, processing stabilizers, and plasticizers.

[0078] The outer sheath 15 may be formed, for example, by spirally wrapping a resin tape containing a resin material around the surface of the shield layer 14, or by extrusion molding or the like. (1-5) Resin tape layer The cable 10 of this embodiment may further have a resin tape layer 12 which includes a resin tape arranged spirally along the longitudinal direction of the twisted wire pair 110.

[0079] The resin tape layer 12 may be placed, for example, between the twisted wire pair 110 and the inner sheath 13.

[0080] The resin tape contained in the resin tape layer 12 may contain resin material.

[0081] Examples of resin materials include one or more selected from polyolefin resins, polyester resins, polyvinyl chloride resins, fluororesins, etc. Examples of polyolefin resins, polyester resins, polyvinyl chloride resins, and fluororesins were explained in the sections on insulator 112 and outer sheath 15, so their explanation is omitted here.

[0082] The cable 10 of this embodiment further includes a resin tape layer 12, which stabilizes the shape of the twisted wires 110. Therefore, in the cable 10 of this embodiment, the shapes of the inner sheath 13, shield layer 14, and outer sheath 15, which are placed outside the twisted wires 110, can also be stabilized, making it easy to achieve a desired shape. (2) Regarding the characteristics of the cable The evaluation methods for repulsive force and pull-out force described below will be explained in the examples. (2-1) Rebound force In this embodiment, the repulsive force of the cable 10 when the cable 10 is bent into a U-shape and the radius of curvature of the bent portion is changed from 100 mm to 50 mm may be 0.5 N or less, or it may be 0.4 N or less.

[0083] When cable 10 is bent into a U-shape, the smaller the radius of curvature at the bend, the stronger the repulsive force. By making the repulsive force 0.5N or less when the radius of curvature at the bend is changed from 100mm to 50mm, a cable that is easily deformable and highly flexible can be made, improving workability and productivity during wiring.

[0084] In the cable 10 of this embodiment, the lower limit of the repulsive force may be, for example, 0.05 N or more, or 0.1 N or more. By setting the repulsive force to 0.05 N or more, the strength and durability of the cable 10 can be increased.

[0085] Therefore, for the cable 10 of this embodiment, the repulsive force may be 0.05N or more and 0.5N or less, or 0.1N or more and 0.4N or less.

[0086] The repulsive force of the cable 10 can be kept within a desired range by selecting, for example, the resin material or compound of the inner sheath 13. (2-2) Pull-out force In this embodiment, if the cable 10 has a shield layer 14 comprising a first shield layer 141 and a second shield layer 142, the pull-out force between the first shield layer 141 and the second shield layer 142 may be 10N or more, or it may be 20N or more.

[0087] By setting the pull-out force between the first shield layer 141 and the second shield layer 142 to 10N or more, the adhesion force at the shield layer 14 is increased, preventing damage when force is applied along the length of the cable 10.

[0088] The pull-out force between the first shield layer 141 and the second shield layer 142 may be 80N or less, or 60N or less.

[0089] By keeping the pull-out force between the first shield layer 141 and the second shield layer 142 to 80N or less, the flexibility of the cable 10 can be particularly enhanced.

[0090] Therefore, for the cable 10 of this embodiment, the pull-out force between the first shield layer 141 and the second shield layer 142 may be 10N or more and 80N or less, or 20N or more and 60N or less. (2-3) Tensile modulus In this embodiment, the cable 10 may have an inner sheath 13 whose tensile modulus is greater than that of the outer sheath 15, and a cable 10 whose tensile modulus is less than that of the insulator 112 of the electric wire 11. The tensile modulus of the outer sheath 15 may be half or less of that of the inner sheath 13, and the modulus of the tensile modulus of the inner sheath 13 may be half or less of that of the insulator 112.

[0091] With respect to the outer sheath 15, inner sheath 13, and insulator 112, the tensile modulus of elasticity may be higher for the components closer to the center of the cable 10.

[0092] When an external force is applied to the cable 10, the components furthest from the center will deform first. Therefore, by making the tensile modulus smallest for the outer sheath 15, which is furthest from the center of the cable 10, and increasing in the order of inner sheath 13 and insulator 112, it is possible to create a cable that is particularly easy to deform and has excellent flexibility.

[0093] In this specification, tensile modulus refers to the tensile modulus measured within the range of 23 ± 2°C. [Examples]

[0094] The present invention will be described with specific examples below, but it is not limited to these examples. (1) Evaluation method First, we will explain the evaluation method for the cables fabricated in the following experimental example. (1-1) Diameter of conductor strands, outer diameter of conductor, outer diameter of insulator, outer diameter of resin tape layer, outer diameter of inner sheath, outer diameter of shield layer, outer diameter of outer sheath, thickness of insulator, thickness of inner sheath, thickness of outer sheath The wire diameter and outer diameter of each part were measured using a micrometer or caliper according to the method described in JIS C 3005 (2014).

[0095] Specifically, the following were measured: the wire diameter D1111 of the conductor strands 1111, the outer diameter D111 of the conductor 111, the outer diameter D112 of the insulator 112, the outer diameter D110 of the twisted wire pair 110, the outer diameter D12 of the resin tape layer, the outer diameter D13 of the inner sheath 13, the outer diameter D14 of the shield layer 14, and the outer diameter D15 of the outer sheath 15.

[0096] To explain the measurement method using conductor 111 as an example, the lengths of two perpendicular diameters were measured for conductor 111 in any cross section perpendicular to the longitudinal side of cable 10, and the arithmetic mean was taken as the outer diameter D111 of conductor 111. The individual wire diameters and outer diameters of each part were measured under the same conditions and procedures, except that the measurement targets were changed to conductor wires 1111, insulator 112, twisted wire pair 110, resin tape layer 12, inner sheath 13, shield layer 14, and outer sheath 15.

[0097] The thickness T112 of the insulator 112 was calculated by subtracting the outer diameter D111 of the conductor 111 from the outer diameter D112 of the insulator 112 and dividing by 2. That is, T112 = (D112 - D111) ÷ 2.

[0098] The thickness T13 of the inner sheath 13 was calculated by subtracting the outer diameter D12 of the resin tape layer 12 from the outer diameter D13 of the inner sheath 13 and dividing by 2.

[0099] The thickness T15 of the outer sheath 15 was calculated by subtracting the outer diameter D14 of the shield layer 14 from the outer diameter D15 of the outer sheath 15 and dividing by 2. (1-2) Cross-sectional area of ​​the inner sheath, cross-sectional area of ​​the outer sheath Based on the measured and calculated outer diameter D13 of the inner sheath 13 and the outer diameter D12 of the resin tape layer 12, the cross-sectional area of ​​the inner sheath 13 was calculated by assuming that the cross-sectional shapes of the inner sheath 13 and the resin tape layer 12 are circles. Specifically, the area of ​​the circle calculated from the outer diameter D13 of the inner sheath 13 was subtracted from the area of ​​the circle calculated from the outer diameter D13 of the inner sheath 13 to obtain the cross-sectional area of ​​the inner sheath 13.

[0100] The cross-sectional area of ​​the outer sheath 15 was calculated by assuming that the cross-sectional shapes of the outer sheath 15 and the shield layer 14 are circles, based on the outer diameter D15 of the outer sheath 15 and the outer diameter D14 of the shield layer 14. Specifically, the area of ​​the circle calculated from the outer diameter D15 of the outer sheath 15 was subtracted from the area of ​​the circle calculated from the outer diameter D15 of the outer sheath 15 to obtain the cross-sectional area of ​​the outer sheath 15. (1-2) Twist pitch, pitch The twist pitch of the twisted wires, the twist pitch of the second shield layer, and the pitch of the resin tape layer were measured in accordance with JIS C 3005 (2014). (1-3) Tensile modulus Tensile tests were performed on the insulator 112, inner sheath 13, and outer sheath 15 of the electric wire 11 in accordance with JIS K 7161 (2024) using a tensile testing machine at a tensile speed of 500 mm / min and a gauge length of 50 mm. (1-4) Rebound force The rebound force was evaluated in accordance with IEC60794-1-2 Method 17c.

[0101] For evaluating the repulsive force, as shown in Figure 2A, the first end 10A of the cable 10 along its longitudinal direction was fixed by a fixing member 22 on the fixing surface 211A of the first fixing plate 211. Then, the cable 10 was bent at the bending portion 101 to form a U-shape, and the second end 10B of the cable 10 along its longitudinal direction was fixed to the fixing member 22 of the second fixing plate 212. The fixing surface 211A of the first fixing plate 211 and the second fixing plate 212 were positioned parallel to each other.

[0102] Then, a load is applied along the block arrow 20 at a speed of 100 mm / min, starting from a state where the radius of curvature R1 at the bent section 101 shown in Figure 2A is 100 mm, until the radius of curvature R2 at the bent section 101 shows 50 mm, causing deformation. The load applied during this time is measured by a load cell (not shown) installed on the second fixing plate 212, and the maximum load from the 100 mm state to the 50 mm state is defined as the rebound force. (1-5) Pull-out force As shown in Figure 3, the measurement was taken using a pull-out force measuring jig 31, which was provided with through-holes of a size and shape that allowed only the components inside the first shield layer 141, namely the first shield layer 141, the inner sheath 13, the resin tape layer 12, and the twisted wire pair 110 to pass through.

[0103] First, the outer sheath 15 and the second shield layer 142 of the cable 10 were removed, with some exceptions. At this time, as shown in Figure 3, the outer sheath 15 and the second shield layer 142 (not shown) were left in such a way that their length L along the longitudinal direction of the cable 10 was 50 mm. In Figure 3, the cross-sectional structure of the cable 10 visible at the top end is omitted.

[0104] Then, the exposed first shield layer 141 was inserted into the through-hole of the pull-out force measuring jig 31. As a result, the cable 10 is set in the adhesion force measuring jig 31, as shown in Figure 3.

[0105] Next, with the pull-out force measuring jig 31 fixed, the cable 10 was pulled at a speed of 250 mm / min along the block arrow 30. Then, the remaining outer sheath 15 and the second shield layer 142 peeled off from the cable 10, and the magnitude of the force applied when the components inside the first shield layer 141 passed through the through-hole of the pull-out force measuring jig 31 and moved downwards from the jig 31 was measured. The measured magnitude of the force was defined as the pull-out force. (1-6) Electrical characteristics The evaluation was conducted in heat resistance class 105°C based on SAE standard J3117-2.

[0106] A rating of A was given if all of the following characteristics passed: impedance, insertion loss (IL), reflection loss (RL), longitudinal conversion loss (LCL), and longitudinal transfer conversion loss (LCTL). A rating of B was given if any one of the evaluated characteristics failed.

[0107] A rating of A means that the electrical properties remain excellent even after a heat resistance test involving heating at 105°C. (2) Experimental conditions and results The cables used in each experimental example are described below.

[0108] Cables for Experimental Examples 1, 2, 3, 4, 5, and 6 were fabricated and evaluated under the conditions shown in Figure 4. Experimental Examples 1 and 2 are comparative examples, while Experimental Examples 3, 4, 5, and 6 are examples.

[0109] In Figure 4, "PP" refers to polypropylene, "PET" refers to polyethylene terephthalate, "AL-PET" refers to a metal tape in which an aluminum metal layer is placed on a polyethylene terephthalate base material, and "PVC" refers to polyvinyl chloride resin. (2-1) Experimental Example 1 A cable 10 was fabricated having the cross-sectional shape shown in Figure 1 and the materials and configuration shown in Figure 4. The resin tape layer 12 is made by spirally winding a resin tape of the width and thickness shown in Figure 4 along the length of the twisted wire 110. The material of the inner sheath 13, "polypropylene (1)", differs from "polypropylene (2)" and "polypropylene (3)" described later in that it contains only polypropylene as the main component of the resin material and does not contain thermoplastic elastomer. The resins of the insulator 112, resin tape layer 12, inner sheath 13, and outer sheath 15 are not crosslinked. The evaluation results are shown in Figure 4. (2-2) Experimental Example 2 Cable 10 was fabricated and evaluated under the same conditions as in Experimental Example 1, except that the metal tape of the first shield layer was wound spirally along the longitudinal side of the inner sheath 13. The evaluation results are shown in Figure 4. (2-3) Experimental Example 3 The resin material of the insulator 112 of the electric wire 11 was changed to XLPE, i.e., cross-linked polyethylene. For the inner sheath 13, "polypropylene (2)" was used instead of "polypropylene (1)". Except for the above points, the cable 10 was fabricated and evaluated under the same conditions as in Experimental Example 1. The evaluation results are shown in Figure 4.

[0110] The material for the inner sheath 13, "Polypropylene (2)," mainly consists of polypropylene and thermoplastic elastomer. (2-4) Experimental Example 4 For the inner sheath 13, "polypropylene (3)" was used instead of "polypropylene (1)". Cable 10 was fabricated and evaluated under the same conditions as in Experimental Example 1, except for the above point. The evaluation results are shown in Figure 4.

[0111] The material for the inner sheath 13, "Polypropylene (3)," mainly consists of polypropylene and thermoplastic elastomer. (2-5) Experimental Example 5, Experimental Example 6 As shown in Figure 4, in Experimental Example 5, the thickness T112 of the insulator 112, the thickness and pitch of the resin tape used in the resin tape layer 12, the thickness T13 of the inner sheath 13, the width and thickness of the metal tape used in the first shield layer 141, and the thickness D15 of the outer sheath 15 were changed.

[0112] In Experimental Example 6, the twist pitch of the twisted wire 110, the thickness and pitch of the resin tape used in the resin tape layer 12, the thickness T13 of the inner sheath 13, the width and thickness of the metal tape used in the first shield layer 141, and the thickness D15 of the outer sheath 15 were changed.

[0113] Except for the points mentioned above, cable 10 was fabricated and evaluated under the same conditions as in Experimental Example 4. The evaluation results are shown in Figure 4.

[0114] As shown in Figure 4, the cables in Experimental Examples 3, 4, 5, and 6 exhibited a repulsive force of 0.5 N or less, confirming that they are highly flexible cables.

[0115] Furthermore, the cables in Experimental Examples 3, 4, 5, and 6 were subjected to a pull-out force of 10N or more, confirming that damage can be prevented even when force is applied along the length of the cable.

[0116] Furthermore, the cables used in Experimental Examples 4, 5, and 6 also received an A rating for their electrical characteristics, confirming their excellent heat resistance and their ability to maintain high electrical performance even when heated. [Explanation of symbols]

[0117] 10 Cables 11 Electric wire 111 Conductor D111 Outer diameter of the conductor 1111 Conductor strand D1111 Wire diameter 112 Insulator D112 Outer diameter of the insulator T112 Insulator thickness 110 stranded wire D110 Outer diameter of twisted-pair wire 12 Resin tape layer D12 Outer diameter of the resin tape layer 13 Inner sheath D13 Inner sheath outer diameter T13 Inner sheath thickness 14 Shield Layer D14 Outer diameter of the shield layer 141 First Shield Layer 142 Second Shield Layer 15 Outer Sheath D15 Outer diameter of the outer sheath T15 Outer sheath thickness 20 Block Arrows 211 1st fixed plate 211A Fixed surface 212 Second fixing plate 22 Fixing member 101 Bending section 10A 1st end 10B 2nd end R1 radius of curvature R2 radius of curvature 30 Block Arrows 31 Jig L Length

Claims

1. A twisted-pair wire, which is made by twisting a pair of wires together, An inner sheath placed outside the aforementioned twisted wire pair, A shield layer placed outside the inner sheath, It has an outer sheath positioned outside the shield layer, A cable in which the repulsive force is 0.5 N or less when bent into a U-shape and the radius of curvature of the bent portion is changed from 100 mm to 50 mm.

2. The cable according to claim 1, wherein the tensile modulus of the inner sheath is greater than the tensile modulus of the outer sheath and less than the tensile modulus of the insulator of the electric wire.

3. The cable according to claim 1 or claim 2, wherein the inner sheath mainly comprises polypropylene.

4. The cable according to claim 3, wherein the inner sheath further comprises a thermoplastic elastomer as a main component.

5. The cable according to claim 1 or claim 2, wherein the insulator of the electric wire contains polypropylene as the main component.

6. The shield layer includes a first shield layer containing a metal tape and a second shield layer containing a metal wire. The cable according to claim 1 or claim 2, wherein the pull-out force between the first shield layer and the second shield layer is 10 N or more.

7. The cable according to claim 1 or claim 2, further comprising a resin tape layer in which resin tape is arranged spirally along the longitudinal direction of the twisted wire pair.

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