cable

Abstract

To provide a cable that prevents the shield performance of a shield layer from being impaired due to bending and twisting.SOLUTION: A cable has: a cable core including one or more wires; a shield layer that is provided around the cable core and is composed of a metal wire; and a sheath provided around the shield layer. The metal wire comprises a copper alloy wire composed of a copper alloy containing indium of 0.3 mass% or more and 0.65 mass% or less and has a tensile strength of 350 MPa or more and an elongation of 7% or more.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] Patent Document 1 (JP 5-311285 A) describes a copper alloy wire containing In and Sn in addition to Cu. Patent Document 2 (JP 2014-159609 A) describes a copper alloy body before wiredrawing, which contains 0.01 atomic % or more of at least one element selected from the group consisting of Ag, In, Mg, and Sn. Patent Document 3 (WO 2014 / 007259 A) describes performing intermediate heat treatment between multiple cold working processes in the production process of a copper alloy material. Patent Document 4 (JP 2015-4118 A) describes performing annealing after drawing and then finish drawing in the production process of a drawn copper wire. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 5-311285 [Patent Document 2] Japanese Patent Application Laid-Open No. 2014-159609 [Patent Document 3] International Publication No. 2014 / 007259 [Patent Document 4] Japanese Patent Application Laid-Open No. 2015-4118 Summary of the Invention [Problem to be solved by the invention]

[0004] Metal wires made of copper alloys are used in a variety of applications. For example, in cables used as internal wiring components in electronic devices, industrial robots, automobiles, and the like, metal wires made of copper alloys are used for the conductors that form the shielding layer. In such cables, it is desirable that the shielding performance is not easily degraded even when the cable is repeatedly bent or twisted. In order to prevent the shielding performance of the shielding layer from being degraded, it is preferable, for example, to make the shielding layer less likely to break when the cable is bent or twisted.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a cable in which the shielding performance of the shielding layer is less likely to deteriorate due to bending or twisting. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems, the present invention provides a cable comprising a cable core including one or more electric wires, a shielding layer made of metal wires arranged around the cable core, and a sheath arranged around the shielding layer, wherein the metal wires are copper alloy wires made of a copper alloy containing 0.3% by mass or more and 0.65% by mass or less of indium, and the cable has a tensile strength of 350 MPa or more and an elongation of 7% or more. [Effects of the Invention]

[0007] According to a representative embodiment of the present invention, it is possible to provide a cable in which the shielding performance of the shielding layer is less likely to deteriorate due to bending or twisting. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic cross-sectional view showing a cross section perpendicular to the longitudinal direction of a cable according to an embodiment of the present invention. [Figure 2] FIG. 2 is a flow chart showing an example of a manufacturing process for a metal wire used in a shielding layer of a cable according to an embodiment of the present invention. [Figure 3] FIG. 1 is a conceptual diagram of a bending test. [Figure 4] FIG. 1 is a conceptual diagram of a twisting test. DETAILED DESCRIPTION OF THE INVENTION

[0009] [Embodiment Mode] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

[0010] Fig. 1 is a schematic cross-sectional view showing a cross section perpendicular to the longitudinal direction of a cable according to this embodiment. Cable 100 shown in Fig. 1 is used as an internal wiring component to be wired inside electronic devices, industrial robots, automobiles, etc., and is particularly suitable for use in locations where repeated bending and twisting occurs.

[0011] Cable 100 includes cable core 103 having insulated wire 101 as one or more electric wires, shielding layer 105 provided to cover the periphery of cable core 103, and sheath 106 provided to cover the periphery of shielding layer 105. Cable 100 according to this embodiment may have a cushion layer (breakage suppression layer) provided between cable core 103 and shielding layer 105 to suppress breakage of the metal wires constituting shielding layer 105 when cable 100 is repeatedly bent or twisted.

[0012] The insulated wire 101 constituting the cable core 103 includes a conductor and an insulator covering the conductor. The conductor is a stranded conductor formed by twisting together metal wires, such as tin-plated annealed copper wires. The stranded conductor may be a concentric stranded conductor formed by twisting together multiple sub-strands, each of which is made up of twisted metal wires. The stranded conductor may also be a compressed conductor, the cross section perpendicular to the longitudinal direction of which is compressed into a circular shape. A compressed conductor is effective for transmitting signals in a high-frequency band of 1 GHz or higher, even when the cable 100 is placed in a location where the cable is repeatedly bent or twisted, or where the cable is repeatedly slid while bent into a U-shape. The insulator may be made of, for example, polyethylene, polypropylene, or fluororesin. The insulator may be a foamed insulator. The insulator may also be a laminated structure formed by stacking multiple insulating layers.

[0013] In the cable core 103, a filler made of a linear body of fiber such as staple fiber yarn is provided around the cable center and the insulated wires 101. The filler is twisted with a plurality of insulated wires 101 (six in this example) to form the cable core 103. This is not a limitation, and the cable core 103 may have a linear body made of fiber only in the cable center. The number of insulated wires 101 constituting the cable core 103 is not limited to that shown in the figure. For example, the cable core 103 may be made of a single insulated wire 101. In this case, the cable 100 becomes a coaxial cable. The cable core 103 may also be formed by twisting together two or more insulated wires 101 to form a stranded wire, which is then twisted with another insulated wire 101.

[0014] A tape 104 is spirally wound around the cable core 103. The tape 104 serves as a holding member that prevents the cable core 103 from untwisting. Examples of the tape 104 that can be used include tape made of paper or nonwoven fabric, and resin tape made of polyethylene (PE). The tape 104 is not essential. When the tape 104 is spirally wound around the cable core 103, the twist of the multiple insulated electric wires 101 that make up the cable core 103 is less likely to untwist than when the tape 104 is not wound around the cable core 103. This makes it less likely that the insulated electric wires 101 will break due to repeated sliding movements. The tape 104 can be replaced with, for example, a resin-coated tape or a tape wound with a filament made of cotton or the like. The tape 104 may not be provided depending on the application.

[0015] The shield layer 105 is a layer for blocking external noise and is provided to cover the periphery of the cable core 103. In this embodiment, a braided shield formed by braiding a plurality of metal wires 107 made of copper alloy wires (described later) is used as the shield layer 105. The braided shield has a braid density of 85% or more and a braid angle of 40 degrees or less. By forming the shield layer 105 using such a braided shield, the flexibility of the cable 100 can be improved, making the shield layer 105 less likely to break even when the cable 100 is repeatedly bent or twisted. The shield layer 105 may be formed by laminating multiple braided shields. When the shield layer 105 is formed by laminating two braided shields, the shield layer 105 includes a first braided shield disposed on the cable core 103 side and a second braided shield disposed around the first braided shield. The first braided shield preferably has a higher braid density than the second braided shield. The braid density of the first braided shield and the second braided shield is 85% or more. The braid angle of the first braided shield is preferably smaller than that of the second braided shield. Having such a braid density and braid angle makes shield layer 105 less likely to break even when cable 100 is repeatedly bent or twisted.

[0016] Here, a braided shield formed by braiding multiple copper alloy metal wires 107 is used for the shield layer 105. However, the present invention is not limited to this. For example, a cross-woven braided shield formed by braiding multiple copper alloy metal wires with fiber wires such as staple fiber, or a cross-woven braided shield formed by braiding multiple copper alloy metal wires with copper foil thread, may also be used for the shield layer 105. Furthermore, the metal wires 107 used for the braided shield may have their surfaces coated with a lubricant such as liquid paraffin. This reduces abrasion between the shield layer 105 and the cable core 103 or between the shield layer 105 and the sheath 106. The braid density of the shield layer 105 is preferably 85% or higher from the viewpoint of shielding external noise. Furthermore, to reduce the outer diameter of the cable 100, a horizontally wound shield formed by helically winding multiple metal wires around the cable core 103 may be used for the shield layer 105 instead of the braided shield. The multiple metal wires constituting the spirally wound shield may be the same as the metal wires constituting the braided shield. The spirally wound shield may have a two-layer structure. In this case, it is preferable that the first spirally wound shield arranged on the cable core 103 side and the second spirally wound shield arranged around the first spirally wound shield have different winding directions. By winding the first spirally wound shield and the second spirally wound shield in different winding directions (opposite directions), the winding state of the metal wires constituting the shield layer 105 is less likely to become distorted when the cable 100 is bent (especially when the cable 100 is bent into a U-shape and repeatedly slid).

[0017] The metal wire 107 constituting the shield layer 105 is made of a copper alloy wire. This copper alloy wire is made of a copper alloy containing 0.3 mass % to 0.65 mass % indium (In). The remainder of the copper alloy contains unavoidable impurities. The tensile strength of the metal wire 107 made of a copper alloy wire is 350 MPa or more (preferably, 350 MPa to 400 MPa), the conductivity of the metal wire 107 is 70% IACS or more (preferably, 70% IACS to 90% IACS), and the elongation of the metal wire 107 is 7% or more (preferably, 7% to 18%). The outer diameter of the metal wire 107 is, for example, 0.05 mm to 0.30 mm.

[0018] The conductivity mentioned above is based on the index "IACS (International Annealed Copper Standard)." The conductivity using IACS is based on annealed standard soft copper (volume resistivity: 1.7241 × 10 -2 The electrical conductivity of 100% IACS is defined as the conductivity of annealed standard soft copper, and the percentage of this conductivity relative to the conductivity of annealed standard soft copper is expressed as "xx% IACS." The above-mentioned conductivity is calculated based on the measurement results of measuring the electrical resistance and diameter of the test piece in accordance with the test method for electrical copper wire specified in the Japanese Industrial Standard (JIS C 3002:1992).

[0019] The "elongation" of the metal wire 107 is determined by conducting a tensile test on a test piece in accordance with the test method for electrical copper wire specified in the Japanese Industrial Standards (JIS C 3002:1992) and calculating the value from the measurement results. The "tensile strength" of the metal wire 107 is determined by conducting a tensile test on a test piece in accordance with the tensile test method for metallic materials specified in the Japanese Industrial Standards (JIS Z 2241:2011) and calculating the value from the measurement results.

[0020] Examples of the unavoidable impurities contained in the copper alloy include aluminum (Al), silicon (Si), phosphorus (P), sulfur (S), chromium (Cr), iron (Fe), nickel (Ni), arsenic (As), selenium (Se), silver (Ag), antimony (Sb), lead (Pb), and bismuth (Bi). The unavoidable impurities contained in the copper alloy are contained in a range of, for example, 20 ppm by mass or more and 30 ppm by mass or less.

[0021] The metal wire 107 made of the above-mentioned copper alloy wire can achieve both high levels of tensile strength and electrical conductivity. As a result of confirmation by the present inventors, a copper alloy wire made of a copper alloy containing 0.3 mass % or more and 0.65 mass % or less of indium (In), with the remainder being copper (Cu) and unavoidable impurities, has electrical conductivity of 70% IACS or more and tensile strength of 350 MPa or more.

[0022] Furthermore, the metal wire 107 constituting the shielding layer 105 may be made of a plated wire in which a plating layer is provided on the outer periphery of a copper alloy wire. The metal wire 107 made of a plated wire has a tensile strength of 350 MPa or more, a conductivity of 80% IACS or more, and an elongation of 7% or more. That is, the metal wire 107 made of a plated wire has a tensile strength of 350 MPa or more (preferably, 350 MPa or more and 400 MPa or less), a conductivity of 70% IACS or more (preferably, 70% IACS or more and 90% IACS or less), and an elongation of 7% or more (preferably, 7% or more and 18% or less) when a plating layer is provided on the outer periphery of the copper alloy wire. The plated wire is a semi-hard wire.

[0023] As described above, the plated metal wire 107 has a copper alloy wire made of a copper alloy containing 0.3% by mass or more and 0.65% by mass or less of indium (In). In particular, the copper alloy wire constituting the plated wire preferably contains 0.3% by mass or more and 0.65% by mass or less of indium (In), with the remainder being copper (Cu) and unavoidable impurities. Alternatively, the copper alloy wire constituting the plated wire may contain 0.3% by mass or more and less than 0.65% by mass of indium (In) and 0.02% by mass or more and less than 0.1% by mass of tin (Sn), with the remainder being copper (Cu) and unavoidable impurities. In this case, the total content of indium and tin contained in the copper alloy is 0.65% by mass or less.

[0024] The plating layer constituting the plated wire is provided around the copper alloy wire so as to contact the surface of the copper alloy wire. The thickness of the plating layer is, for example, 0.1 μm or more and 1.5 μm or less. The plating layer is made of, for example, tin (Sn), silver (Ag), nickel (Ni), etc.

[0025] The metal wire 107 made of a copper alloy wire constituting the shielding layer 105 can be improved by inducing strain in the copper alloy. Methods for inducing strain in a copper alloy include increasing the content of metal elements other than copper in the copper alloy and performing wire drawing. However, when strain is inducing strain in a copper alloy wire by these methods, the resistivity of the copper alloy as a conductive member increases, thereby decreasing the conductivity of the copper alloy wire. In other words, there is a trade-off between increasing the tensile strength of a copper alloy wire and increasing the conductivity of the copper alloy wire.

[0026] Therefore, in order to find a configuration that improves the electrical conductivity and tensile strength of solid-solution strengthened copper alloys, the inventors focused on the effect of several types of metal elements on the decrease in electrical conductivity of the copper alloy when they are solid-solved in the copper alloy, and the degree to which they contribute to improving tensile strength. That is, the degree to which they contribute to improving the tensile strength of a copper alloy wire varies depending on the type of metal element, and the tensile strength increases proportionally as the content of the element solid-solved in copper increases. Tin (Sn) and indium (In) are effective additive elements because they have a greater effect on increasing tensile strength when solid-solved in copper than metals such as aluminum (Al), nickel (Ni), or magnesium (Mg).

[0027] On the other hand, the degree of influence on the decrease in conductivity varies greatly depending on the type of metal element. Specifically, compared to metals such as nickel (Ni), tin (Sn), and aluminum (Al), silver (Ag), indium (In), and magnesium (Mg) can suppress the decrease in conductivity even when their concentration in copper is high. For example, when the concentration (mass concentration) of the above metal elements dissolved in oxygen-free copper is 900 ppm, the conductivity of tin (Sn) decreases to about 92% of that of pure copper (taken as 100% (percentage)), while the conductivity of indium (In) decreases to only about 98%. Furthermore, the conductivity of silver (Ag) decreases to only about 99% of that of pure copper (taken as 100% (percentage)).

[0028] From the above-mentioned characteristics, the copper alloy obtained by dissolving indium in copper has high levels of electrical conductivity and tensile strength. In addition, in the case of a copper alloy in which silver (Ag) is dissolved in copper, an even higher electrical conductivity than the copper alloy wire of the present embodiment can be obtained. However, since silver has a smaller effect on increasing tensile strength than indium at the same concentration, increasing the silver content increases the raw material cost of the copper alloy wire, so it is preferable to dissolve indium.

[0029] In addition, in order to improve the tensile strength of the copper alloy, it is preferable that the oxygen content of the copper alloy is low. In the present embodiment, the oxygen content of the copper alloy is 0.002 mass% or less. If the oxygen content of the copper alloy is 0.002 mass% or less, it is possible to prevent the tensile strength of the copper alloy from being reduced due to oxygen.

[0030] As a modification of the metal wire 107, the copper alloy wire may be a copper alloy containing 0.3 mass % or more but less than 0.65 mass % indium (In), 0.02 mass % or more but less than 0.1 mass % tin (Sn), and the remainder being copper (Cu) and unavoidable impurities, provided that the total content of indium and tin contained in the copper alloy is 0.65 mass % or less.

[0031] In the modified example of the metal wire 107, the copper alloy contains tin in a solid solution, so the conductivity is relatively low compared to the above-mentioned copper alloy wire that does not contain tin. However, by setting the tin content to less than 0.1 mass % and adding 0.3 mass % or more of indium, a conductivity of 70% IACS or more can be maintained. However, the total content of indium and tin contained in the copper alloy is preferably 0.65 mass % or less. In this way, in the modified example of the copper alloy wire, by solidifying tin at a predetermined content, it is possible to maintain a conductivity of 70% IACS or more and reduce the raw material cost of the copper alloy wire.

[0032] Sheath 106 covers the periphery of shield layer 105 and plays a role in protecting shield layer 105 and cable core 103. Sheath 106 is made of, for example, polyvinyl chloride resin, urethane resin, fluororesin, fluororubber, etc., and is made of a resin composition having at least one of these resins as a main component (base).

[0033] <Metal Wire Manufacturing Method> Next, a method for manufacturing the metal wire 107 that constitutes the shielding layer 105 of the cable 100 will be described. The above-mentioned metal wire 107 may or may not contain tin in the copper alloy, but the manufacturing method is the same. Figure 2 is a flow chart showing an example of a manufacturing process for the metal wire 107 used in the shielding layer 105 of the cable 100.

[0034] In the following, a method for manufacturing a metal wire will be described in which a wire rod having a certain outer diameter (for example, about 8 mm to 12 mm) is manufactured by a continuous casting and rolling method, and then the wire rod is drawn to manufacture a metal wire. The continuous casting and rolling method may be, for example, a continuous casting and rolling method called the SCR system (Southwire Continuous Rod system).

[0035] First, in the raw material preparation step shown in FIG. 2, a raw material is prepared. The raw material is a metal whose main component is copper. In addition to copper, the raw material may contain impurity elements that are inevitably mixed in, as described above. The raw material also contains additive elements including indium. In the metal wire manufacturing method described as a modified example of the metal wire, the additive elements are indium and tin. These additive elements are added to the copper-based raw material within a range that satisfies the above-mentioned content conditions.

[0036] Next, in the melting process shown in Fig. 2, the raw materials are melted in a melting furnace (not shown). The melting furnace is a heating furnace that can continuously melt the raw materials, and the molten copper melted in the melting furnace is transferred sequentially to a heat-retaining furnace (not shown).

[0037] Next, in the casting process shown in FIG. 2, the molten copper in the heat-retaining furnace is poured into a mold (not shown) and then cooled to solidify. The solidified casting is removed from the mold and sequentially sent to a rolling mill. The melting process to the casting process shown in FIG. 2 are carried out in an inert gas atmosphere (e.g., a nitrogen atmosphere). There is almost no oxygen in the inert gas atmosphere, and at least the oxygen concentration (volume concentration) is 10 ppm or less. In this way, by manufacturing the wire rod in an inert gas atmosphere with an extremely low oxygen concentration, it is possible to suppress the inclusion of oxygen in the copper during the casting process.

[0038] Next, in the rolling step shown in Fig. 2, the casting is rolled to form a wire rod having an outer diameter of about 8 mm to 12 mm. In the rolling step, the rolling treatment may be performed multiple times. Note that if the casting obtained in the casting step is used as a wire rod as is, this rolling step can be omitted. Furthermore, the wire rod may be subjected to a surface cleaning treatment such as oxide removal after the rolling step.

[0039] Next, in the winding step shown in FIG. 2, the wire is wound by a winding device (not shown) to obtain a roll of the wire.

[0040] Next, in the wiredrawing process shown in Fig. 2, the roughly drawn wire is drawn until it has a desired outer diameter (for example, 0.05 mm or more and 0.30 mm or less) to obtain a drawn wire material of a hard material. The wiredrawing process is carried out at room temperature (for example, 25°C), which is so-called cold working. In the wiredrawing process, the roughly drawn wire is elongated in the extension direction, but the wiredrawing process is divided into multiple steps (a first wiredrawing process step and a second wiredrawing process step), and a heat treatment process (sometimes called an annealing process) is carried out between the wiredrawing processes to apply heat treatment to the drawn wire material during the wiredrawing process.

[0041] During the wiredrawing process, strain is generated in the metal wire, which increases the tensile strength of the metal wire but decreases the electrical conductivity of the metal wire. Heat treatment during the wiredrawing process reduces the strain in the metal wire. Therefore, the tensile strength of the heat-treated metal wire decreases but its electrical conductivity increases. The inventors of the present application have found that by performing a heat treatment process during the wiredrawing process (between the first wiredrawing process and the second wiredrawing process) so as to satisfy the following conditions, the tensile strength and electrical conductivity of the final semi-hard metal wire can be maintained at a high level. The semi-hard metal wire referred to here is a metal wire with an elongation of 7% or more and 18% or less.

[0042] Assuming that the tensile strength of the metal wire before heat treatment (after the wiredrawing process immediately before heat treatment) is A, the tensile strength of the metal wire after heat treatment (immediately after heat treatment) is B, and C = B / A, the heat treatment is performed so that the tensile strength ratio C is 0.5 to 0.8. Furthermore, assuming that the elongation of the metal wire before heat treatment (after the wiredrawing process immediately before heat treatment) is D, the elongation of the metal wire after heat treatment (immediately after heat treatment) is E, and F = E / D, the heat treatment is performed so that the elongation ratio F is 10 to 50. Note that, as shown in FIG. 2, because further wiredrawing is performed after the heat treatment, the heat treatment is preferably performed so that the electrical conductivity of the metal wire immediately after the heat treatment is 86% IACS or higher (preferably 88% IACS or higher). Furthermore, the tensile strength of the metal wire immediately after the heat treatment is preferably 60 MPa to 200 MPa, and the elongation of the metal wire immediately after the heat treatment is preferably 20% to 40%. This allows the electrical conductivity to be 70% IACS or higher after the wire drawing process (second wire drawing process) that follows the heat treatment process. Note that the heat treatment process described above is preferably performed at a temperature of 400°C or higher and 900°C or lower.

[0043] 2 illustrates an embodiment in which a rough wire is drawn to a desired outer diameter (e.g., an outer diameter of 0.50 mm or more and 3.00 mm or less) in a wiredrawing process (first wiredrawing process), the drawn wire is then subjected to a heat treatment process under the conditions described above, and the drawn wire is then drawn to a desired outer diameter (e.g., an outer diameter of 0.05 mm or more and 0.30 mm or less) in a wiredrawing process (second wiredrawing process). However, various modifications are also applicable. For example, the second wiredrawing process may be divided into multiple wiredrawing processes, and the drawn wire may be drawn stepwise to the desired wire diameter in each of the multiple wiredrawing processes. By drawing the drawn wire stepwise through multiple wiredrawing processes in the second wiredrawing process, the hard drawn wire described above can be obtained more reliably than when the second wiredrawing process is composed of a single wiredrawing process. In addition, when the second wiredrawing process is composed of multiple wiredrawing processes, the above-mentioned heat treatment process may be performed between the multiple wiredrawing processes as needed. The hard drawn wire material referred to here is a metal wire with an elongation of 0.5% to 3% and an outer diameter of 0.05 mm to 0.30 mm.

[0044] Next, the hard wire drawn material having the desired outer diameter obtained in the wiredrawing process is subjected to a semi-hardening treatment. By subjecting the hard wire drawn material to the semi-hardening treatment, a copper alloy wire in a semi-hard state is obtained. For example, the semi-hardening treatment may involve heating the hard wire drawn material obtained in the wiredrawing process under heating conditions such as a heating temperature of 520°C to 580°C and a heating time of 0.3 seconds to 0.8 seconds. This results in a copper alloy wire having a tensile strength of 350 MPa to 400 MPa, an electrical conductivity of 70% IACS to 90% IACS, an elongation of 7% to 18%, and an outer diameter of 0.05 mm to 0.30 mm. The copper alloy wire obtained in this manner can be used as the metal wire 107 of the shielding layer 105.

[0045] The plated metal wire 107 is obtained by forming a plating layer on a copper alloy wire obtained by the metal wire manufacturing method shown in FIG. 2. The copper alloy wire before the plating layer is formed is a semi-hard metal wire with a tensile strength of 350 MPa or more and a conductivity of 70% IACS or more. The copper alloy wire is immersed in a plating tank containing a molten plating material (e.g., Sn) at a predetermined temperature (e.g., 250°C to 300°C). This applies a hot-dip coating to the entire outer surface of the copper alloy wire. The copper alloy wire coated with the hot-dip coating is then passed through a plating die to adjust the thickness of the hot-dip coating applied to the surface of the copper alloy wire, thereby forming a plating layer with a predetermined thickness. In particular, the hot-dip coating is preferably applied to the surface of the copper alloy wire at a linear speed of 100 m / min or more for an immersion time in the hot-dip coating of 0.1 to 1.0 seconds. The copper alloy wire on which the plating layer is formed in this manner maintains a semi-hard state and has an elongation of 7% to 18%.

[0046] <Example> Next, the results of evaluation of the characteristics of the cable 100 will be described.

[0047] In this example, a cable was used in which a tape was spirally wrapped around a cable core containing four insulated wires, a braided shield (shield layer) was provided around the tape by braiding multiple metal wires, and a sheath was provided around the braided shield.The cable core was made by twisting together insulated wires coated with an insulator (thickness: approximately 0.13 mm) made of fluororesin by tube extrusion and a filler made of staple fiber yarn around a conductor made of 60 / 0.08 mm (60 wires with an outer diameter of 0.08 mm) bunched stranded wire (twist pitch: approximately 15 mm) equivalent to 23 AWG (American wire gauge). The metal wire of the braided shield is a copper alloy wire containing 0.3% to 0.65% by mass of indium, surrounded by a tin-plated layer. The plated wire (outer diameter: approximately 0.08 mm) has a tensile strength of 350 MPa to 400 MPa, a conductivity of 70% IACS to 90% IACS, and an elongation of 7% to 18%. The braided shield has a braid density of 85% or more and a braid angle of 30° to 40°. The sheath is made of a resin composition primarily composed of polyvinyl chloride resin, which is coated on the outer periphery of the braided shield by tube extrusion. The cable has an outer diameter of approximately 8 mm.

[0048] (Bending test) A bending test was carried out on the cable having the above configuration.

[0049] As shown in Figure 3, the bending test was performed by hanging a weight with a load W = 500 gf from the bottom end of the sample cable, attaching bending jigs 43 curved on both sides of the cable, and moving the cable along the bending jig 43 to bend it horizontally at a bending angle X = ±90°. The bending radius (R) was 25 mm. The bending speed was 30 times / min, and one round trip in the horizontal direction was counted as one bending. The cable was then repeatedly bent, and the resistance of the shield layer was measured between both ends of the cable after each bending. The shield layer was considered to have broken when the resistance measured during the bending test increased by 20% compared to the resistance before the bending test (initial resistance). The number of bending times at that point was defined as the flex life.

[0050] As a result of the bending test, the cable according to this example showed an increase in resistance of less than 20% even after 3.3 million bending cycles, and the shielding layer was not considered to have broken. From this result, it can be considered that the shielding performance of the shielding layer of the cable according to this example is unlikely to deteriorate when repeatedly bent.

[0051] (Twist test) A twisting test was carried out on the cable having the above configuration.

[0052] As shown in Figure 4, the twisting test involved attaching one portion of the sample cable to a fixed chuck 52, and another portion above it, separated by a twist length d = 500 mm, to a rotating chuck 54. A weight with a load W = 1100 gf was then suspended from the lower end of the cable. Rotating chuck 54 was then rotated to apply a ±180° twist to the portion of the cable between fixed chuck 52 and rotating chuck 54. Rotating chuck 54 was rotated +180°, then -180°, and then returned to its original position. This rotation, indicated by arrows 5a, 5b, 5c, and 5d, constituted one cycle (counted as one turn). The twisting speed was 30 turns per minute, and one round trip in each direction was counted as one turn. The cable was then repeatedly twisted, and the resistance of the shield layer was measured between both ends of the cable after each appropriate twist. The shield layer was deemed to have broken when the resistance value measured during the twisting test increased by 20% compared to the resistance value before the twisting test (initial resistance value), and the number of twists at that time was taken as the twisting life.

[0053] As a result of the twisting test, the cable according to this example showed that the resistance value of the shield layer increased by less than 20% even after 180,000 twists, and the shield layer was not considered to have broken. From this result, it can be considered that the shielding performance of the cable according to this example is unlikely to deteriorate when twisted repeatedly.

[0054] (Summary of the embodiment) Next, the technical ideas grasped from the above-described embodiments will be described by using the reference numerals and the like in the embodiments. However, the reference numerals and the like in the following description do not limit the components in the claims to the members and the like specifically shown in the embodiments.

[0055] [1] A cable (100) comprising: a cable core (103) including one or more electric wires; a shielding layer (105) consisting of a metal wire (107) arranged around the cable core (103); and a sheath (106) arranged around the shielding layer (105), wherein the metal wire (107) is made of a copper alloy wire made of a copper alloy containing 0.3% by mass or more and 0.65% by mass or less of indium, and has a tensile strength of 350 MPa or more and an elongation of 7% or more.

[0056] [2] The cable (100) according to [1], wherein the copper alloy wire is made of a copper alloy containing tin at a concentration of 0.02% by mass or more and less than 0.1% by mass, and the total content of the indium and the tin is 0.65% by mass or less.

[0057] [3] The cable (100) according to [1] or [2], wherein the metal wire (107) is a plated wire having a plating layer provided around the copper alloy wire, and has a tensile strength of 350 MPa or more and an elongation of 7% or more.

[0058] [4] The cable (100) according to any one of [1] to [3], wherein the metal wire (107) has a conductivity of 70% IACS or more.

[0059] [5] The cable (100) according to any one of [1] to [4], wherein the shield layer (105) is made of a braided shield having a braid density of 85% or more and a braid angle of 40 degrees or less.

[0060] Although the embodiments of the present invention have been described above, the invention according to the claims is not limited to the above-described embodiments. It should be noted that not all of the combinations of features described in the embodiments are necessarily essential to the means for solving the problems of the invention. Furthermore, the present invention can be appropriately modified and implemented within the scope of its spirit. [Explanation of symbols]

[0061] 100 Cable 101 Insulated wire 103 Cable Core 104 Tape 105 Shielding Layer 106 Sheath 107 Metal Wire

Claims

1. A cable core in which a plurality of electric wires are twisted together; a shield layer made of a metal wire provided around the cable core; a sheath provided around the shield layer, the metal wire is a copper alloy wire made of a copper alloy containing 0.3 mass% or more and 0.65 mass% or less of indium and 0.02 mass% or more and less than 0.1 mass% of tin, wherein the total content of the indium and the tin is 0.65 mass% or less, The metal wire has a tensile strength of 350 MPa or more and an elongation of 7% or more, The shield layer is configured by laminating two layers of braided shields, each having a braid density of 85% or more and a braid angle of 40 degrees or less, the two-layer braided shield includes a first braided shield disposed on the cable core side and a second braided shield disposed around the first braided shield, the first braided shield has a higher braid density than the second braided shield; The first braided shield has a smaller braid angle than the second braided shield. cable.

2. The metal wire is a plated wire having a plating layer provided around the copper alloy wire. The cable of claim 1 .

3. The metal wire has a conductivity of 70% IACS or more.

3. The cable according to claim 1 or 2.

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