cable

Abstract

Provided is a cable that can be made lightweight, easily routed, and in which a metal wire that forms a shield layer is less likely to break even if the cable is bent. A cable (1) includes a cable core (3) having one or more electric wires (2), a shield layer (5) that covers the periphery of the cable core (3), and a sheath (6) that covers the periphery of the shield layer (5), and the shield layer (5) is formed of a braided shield that is formed by braiding a plurality of first metal wires (51) made of aluminum or an aluminum alloy and a plurality of second metal wires (52) made of copper or a copper alloy in a crisscross manner.

Description

TECHNICAL FIELD

[0001] The present application relates to a cable. BACKGROUND

[0002] As a countermeasure for improving productivity in a factory or the like, the spread of industrial robots such as human-robot collaborative robots and small multi-joint robots is expanding. As a cable used in an industrial robot, there are a movable section cable that is routed to a movable section of an industrial robot, and a fixed section cable that connects an industrial robot and a control device or the like. Among them, as a cable used as a fixed section cable, as a countermeasure against external noise in a factory or the like, a cable provided with a shield layer around a cable core is used. As the shield layer, a braided shield made of braiding a metal wire made of copper or a copper alloy is widely used.

[0003] Note that, as prior art document information related to the present application, there is Patent Literature 1.

[0004] PRIOR ART DOCUMENT

[0005] PATENT LITERATURE

[0006] Patent Literature 1: Japanese Patent Application Publication No. 2014-71974 SUMMARY

[0007] PROBLEMS TO BE SOLVED BY THE INVENTION

[0008] However, since the cable used as the above-described fixed section cable connects an industrial robot and a control device or the like in a factory or the like, the cable length becomes long (for example, about 25 m to 50 m or so). In addition, in recent years, the number of electric wires built in the cable has also increased to, for example, 40 or more, and the cable outer diameter has also increased to, for example, 20 mm or more.

[0009] Therefore, in the cable using a braided shield made of braiding a metal wire made of copper or a copper alloy as a shield layer, the weight of the cable becomes very heavy (for example, about 30% of the total copper amount in the cable becomes the copper amount of the shield layer). Therefore, the burden on the worker who performs the routing work and the carrying work of the cable increases, and attention is also required for the safety assurance of the work.

[0010] In addition, in the cable using a braided shield made of braiding a metal wire made of copper or a copper alloy as a shield layer, since the rigidity (restoring force to return to a straight shape when the cable is bent) of the shield layer is large, it is also sometimes difficult to bend the cable with a small bending radius. Therefore, for example, at the time of routing work of the cable, it is difficult to bend the cable into a desired shape that matches the routing space and perform routing, and, for example, at the time of carrying work, it is also difficult to compactly store the cable in a storage case or the like and perform carrying or the like, and the operability of the cable deteriorates.

[0011] To solve this problem, for example, consider using a braided shield made of braiding metal wires composed of aluminum or an aluminum alloy in the shielding layer. However, in this case, although the cable becomes lightweight, abrasion of the metal wires caused by friction between the metal wires themselves easily occurs when the cable is bent, and the metal wires are easily broken. If a break occurs in the metal wires that make up the shielding layer, the function as a shielding layer is reduced.

[0012] Therefore, an object of the present application is to provide a cable that can be lightweight, easily routed, and in which the metal wires that make up the shielding layer are not easily broken even if the cable is bent.

[0013] Method for solving the problem

[0014] The present application provides a cable that can be lightweight, easily routed, and in which the metal wires that make up the shielding layer are not easily broken even if the cable is bent.

[0015] Effects of the Invention

[0016] According to the present application, a cable that can be lightweight, easily routed, and in which the metal wires that make up the shielding layer are not easily broken even if the cable is bent can be provided. BRIEF DESCRIPTION OF DRAWINGS

[0017] FIG. 1(a) is a cross-sectional view showing a cross section perpendicular to the length direction of a cable according to an embodiment of the present application, and FIG. 1(b) is a schematic view of a shielding layer.

[0018] Explanation of Symbols

[0019] 1...cable, 2...wire, 3...cable core, 4...pressing wrap tape, 5...shielding layer, 6...jacket, 51...first metal wire, 52...second metal wire. DETAILED DESCRIPTION

[0020] [Embodiment]

[0021] Hereinafter, an embodiment of the present application will be described with reference to the drawings.

[0022] FIG. 1(a) is a cross-sectional view showing a cross section perpendicular to the length direction of a cable according to an embodiment of the present application, and FIG. 1(b) is a schematic view of a shielding layer. The cable 1 is used, for example, as a fixed portion cable that connects industrial robots and control equipment, etc. in factories, etc.

[0023] As shown in FIG. 1(a), FIG. 1(b), the electric cable 1 has a cable core 3 having one or more electric wires 2, a shield layer 5 covering the periphery of the cable core 3, and a sheath 6 covering the periphery of the shield layer 5.

[0024] The electric wire 2 has a conductor 21 and an insulator 22 covering the periphery of the conductor 21. The conductor 21 is composed of a stranded conductor in which a plurality of metal wires are stranded. In the present embodiment, the conductor 21 is composed of a stranded body in which 37 metal wires each composed of a tinned soft copper wire having an outer diameter of 0.26 mm are collectively stranded. The stranding pitch of the conductor 21 is, for example, 29 mm or more and 40 mm or less. In addition, the outer diameter of the conductor 21 is about 1.8 mm, and the conductor size is 15 AWG. Note that the outer diameter of the conductor 21 and the conductor size are not limited thereto, and the outer diameter of the conductor 21 and the conductor size can be the same in each of the plurality of electric wires 2.

[0025] As the insulator 22, an insulator composed of a polyvinyl chloride resin composition is used. The thickness of the insulator 22 is, for example, 0.5 mm or more and 0.7 mm or less, and the outer diameter of the insulator 22 (the outer diameter of the electric wire 2) is 2.9 mm or more and 3.1 mm or less.

[0026] The cable core 3 is composed of a plurality of electric wires 2 stranded in a spiral shape around a central fitting member 7 disposed at the center of the electric cable. In the present embodiment, for example, as shown in FIG. 1(a), a cable core 3 in which the electric wires 2 are stranded in three layers can be used, in which 8 electric wires 2 are stranded around the central fitting member 7 as a first layer, 14 electric wires 2 are further stranded around the first layer as a second layer, and 20 electric wires 2 are further stranded around the second layer as a third layer. At this time, the total number of the electric wires 2 constituting the cable core 3 is 42. The electric wires 2 of each layer are stranded in the same direction. The outer diameter of the cable core 3 is about 22 mm to 23 mm. Note that the number of the electric wires 2 constituting the cable core 3 is set to 42 in this case, but the number of the electric wires 2 constituting the cable core 3 is not limited thereto, and can be one or more. In the case where the cable core 3 is composed of one electric wire 2 disposed at the center of the electric cable (without the central fitting member 7), the electric cable 1 becomes a coaxial electric cable.

[0027] The central fitting member 7 is composed of a plurality of fiber-like bodies (filament-like bodies) bundled. In the present embodiment, 50 short fiber yarns of No. 10 (10s / 1) are bundled to serve as the central fitting member 7. Note that the material and the number of the filament-like bodies constituting the central fitting member 7 are not limited thereto. The central fitting member 7 is disposed only at the center of the electric cable, and is not disposed between the electric wires 2 of each layer, nor between the electric wire 2 and the press-wound tape 4. In addition, the central fitting member 7 is disposed so as to enter between the electric wires 2 of the first layer constituting the cable core 3 (between the electric wires 2 adjacent in the circumferential direction in the first layer).

[0028] A pressing winding tape 4 is spirally wound around the cable core 3. The pressing winding tape 4 functions to maintain the twist of the cable core 3, and is spirally wound around the cable core 3 with a portion thereof overlapping in the width direction. The winding direction of the pressing winding tape 4 is set to the same direction as the twisting direction of the cable core 3. Note that the winding direction of the pressing winding tape 4 is the direction in which the pressing winding tape 4 is rotated from the other end to the one end of the cable 1. Further, the twisting direction of the cable core 3 is the direction in which the electric wire 2 is rotated from the other end to the one end of the cable 1. As the pressing winding tape 4, a tape made of paper or nonwoven fabric, or a resin tape made of a resin such as polyethylene can be used. Note that the pressing winding tape 4 is not essential, and for example, in the case where the cable core 3 is made of one electric wire 2, the pressing winding tape 4 that functions to maintain the twist of the cable core 3 can be omitted.

[0029] The shield layer 5 is provided so as to cover around the pressing winding tape 4. Details of the shield layer 5 are described later.

[0030] The sheath 6 is provided so as to cover around the shield layer 5, for the purpose of protecting the shield layer 5 and the cable core 3. In the present embodiment, the sheath 6 is made of a polyvinyl chloride resin composition. The thickness of the sheath 6 is 1.1 mm or more and 1.3 mm or less, and the outer diameter of the sheath 6 (the outer diameter of the cable 1) is about 26 mm.

[0031] (Shield layer 5)

[0032] As shown in Fig. 1(b), in the cable 1 of the present embodiment, the shield layer 5 is made of a braided shield that is braided with a plurality of first metal wires 51 made of aluminum or an aluminum alloy and a plurality of second metal wires 52 made of copper or a copper alloy in a crisscross manner.

[0033] Thus, the shield layer 5 can be made lighter in weight than a braided shield made of metal wires made of only copper or a copper alloy. Further, by the shield layer 5 including the first metal wires 51 made of aluminum or an aluminum alloy having a low yield strength, the shield layer 5 becomes soft and it becomes easy to bend the cable 1. Further, the shield layer 5 is less likely to cause breakage of the metal wires due to friction between the metal wires when the cable 1 is bent, compared to a braided shield made of metal wires made of only aluminum or an aluminum alloy. This is because, compared to a braided shield made of metal wires made of aluminum or an aluminum alloy, a braided shield made of the first metal wires 51 made of aluminum or an aluminum alloy and the second metal wires 52 made of copper or a copper alloy is less likely to cause abrasion when the metal wires rub against each other because the metal wires easily slide against each other.

[0034] In addition, when connecting the end of the electric cable 1 to a substrate or the like, the braided shield formed of the metal wires composed of only aluminum or aluminum alloy is difficult to connect by soldering. In contrast, in the present embodiment, since the second metal wires 52 composed of copper or copper alloy are included in the shield layer 5, connection by soldering can be easily performed.

[0035] Further, when processing the end of the electric cable 1, there is a case where the shield layer 5 is exposed at the end of the electric cable 1, the exposed shield layer 5 (braided shield) is untangled using a dedicated tool or the like, and the untangled and scattered metal wires 51, 52 are bundled in a manner branched from the electric cable core 3 to be connected to a substrate or the like. In this case, the shield layer 5 is connected to the substrate or the like by fastening the bundled metal wires 51, 52 or by soldering, whereby the connection of the shield layer 5 to the substrate or the like is performed. In the present embodiment, the shield layer 5 includes the first metal wires 51 composed of aluminum or aluminum alloy having a low yield strength, and thus the operation of untangling the shield layer 5 can be easily performed compared to the braided shield composed of only copper. Further, when the untangled metal wires 51, 52 are bundled, the first metal wires 51 also function to maintain the shape, and thus the metal wires 51, 52 can be easily bundled into a desired shape. Note that, when the metal wires 51, 52 are bundled, the second metal wires 52 are bundled around the first metal wires 51 in a manner wound in a spiral shape, whereby connection by soldering can be easily performed.

[0036] In the present embodiment, as the first metal wires 51 composed of aluminum, for example, an aluminum wire composed of pure aluminum can be used. In addition, as the first metal wires 51 composed of aluminum alloy, for example, an aluminum alloy wire containing one or more metal elements among magnesium, iron, zirconium, nickel, manganese, zinc, cobalt, titanium, and the like in a prescribed content can be used. In addition, as the second metal wires 52 composed of copper, a tinned soft copper wire in which a surface of a soft copper wire is provided with tin plating can be used. In addition, as the second metal wires 52 composed of copper alloy, for example, a copper alloy wire containing one or more metal elements among magnesium, tin, indium, silver, nickel, zinc, and the like in a prescribed content can be used. Note that, the above-mentioned soft copper wire can use tough copper, oxygen-free copper, or the like. In the present embodiment, in order to further suppress breakage of the metal wires due to friction between the metal wires, liquid paraffin can be applied to a surface of the second metal wires 52 (for example, a surface of the tinned soft copper wire) as lubricating oil.

[0037] Further, in the present embodiment, the cross-sectional area of the first metal wire 51 (e.g., a pure aluminum wire) made of aluminum or an aluminum alloy is larger than the cross-sectional area of the second metal wire 52 (e.g., a tinned soft copper wire) made of copper or a copper alloy. Thus, in the portion where the two metal wires 51, 52 cross, a gap is easily generated between the first metal wire 51 and the second metal wire 52, and the breakage of the metal wires due to the friction between the metal wires when the cable 1 is bent can be further suppressed. Further, by making the cross-sectional area of the first metal wire 51 larger than the cross-sectional area of the second metal wire 52, the first metal wire 51 and the second metal wire 52 can be visually distinguished from each other according to the difference in the outer diameter. As a result, the boundary (step) between the first metal wire 51 and the second metal wire 52 can be easily visually confirmed at the time of the terminal processing, and the operation of inserting a tool or the like into the boundary (step) to untwist the braided shield can be facilitated. Note that the cross-sectional area of the first metal wire 51 refers to the area of the cross section perpendicular to the length direction of the first metal wire 51, and the cross-sectional area of the second metal wire 52 refers to the area of the cross section perpendicular to the length direction of the second metal wire 52.

[0038] More specifically, in a cross-sectional view perpendicular to the length direction of the cable, the cross-sectional area of the first metal wire 51 is 1.5 times or more and 2.0 times or less of the cross-sectional area of the second metal wire 52. By making the cross-sectional area of the first metal wire 51 1.5 times or more of the cross-sectional area of the second metal wire 52, even if the first metal wire 51 is made of aluminum (or an aluminum alloy) having a lower electrical conductivity than copper, the increase in the resistance of the shield layer 5 can be suppressed, and the reduction in the shielding effect can be suppressed. Further, by making the cross-sectional area of the first metal wire 51 2.0 times or less of the cross-sectional area of the second metal wire 52, the difference in the outer diameter of the wires can be suppressed from becoming too large, and the generation of undulations or deformations in the braided shield at the time of manufacturing the braided shield due to the difference in the length of the two metal wires 51, 52 can be suppressed. If undulations or deformations are generated in the braided shield, damage to the portion where the undulations or deformations are generated is likely to occur during the manufacturing process, and breakage is likely to occur. By suppressing the cross-sectional area of the first metal wire 51 to be 2.0 times or less of the cross-sectional area of the second metal wire 52, damage during the manufacturing process can be suppressed. In the present embodiment, for example, a tinned soft copper wire having an outer diameter of 0.12 mm (cross-sectional area of about 0.011 mm 2 ) can be used as the second metal wire 52, and a pure aluminum wire having an outer diameter of 0.15 mm or more and 0.17 mm or less (cross-sectional area of about 0.018 mm 2 or more and about 0.023 mm 2 or less) can be used as the first metal wire 51.

[0039] As the first metal wire 51 and the second metal wire 52, a soft material that is easy to bend is preferably used. More specifically, the first metal wire 51 can have a tensile strength of 90 MPa or more, an elongation of 1.0% or more, and an electrical conductivity of 60% or more. In addition, the second metal wire 52 can have a tensile strength of 200 MPa or more, an elongation of 10% or more, and an electrical conductivity of 98% or more. Thereby, the breakage of the metal wires 51, 52 caused by the tensile stress at the time of bending the cable 1 can be suppressed, and the ease of bending of the cable 1 can be maintained.

[0040] The number of twists (the number of twists) of the braided shield that constitutes the shield layer 5 is, for example, 16 or 24. In the case of 16, 8 twists are constituted only by the first metal wire 51, and the remaining 8 twists are constituted only by the second metal wire 52. The number of strands (the number of strands) of both the first metal wire 51 and the second metal wire 52 is the same. That is, the number of the first metal wires 51 and the number of the second metal wires 52 used in the shield layer 5 are the same number.

[0041] Since the number of the first metal wires 51 and the number of the second metal wires 52 are the same, and in addition, the cross-sectional area of the first metal wire 51 is larger than the cross-sectional area of the second metal wire 52, in the shield layer 5, the proportion of the cross-sectional area of the entire first metal wire 51 is larger than the proportion of the cross-sectional area of the entire second metal wire 52. More specifically, in a cross-sectional view perpendicular to the cable length direction, the proportion of the total of the cross-sectional areas of the first metal wires 51 with respect to the cross-sectional area of the entire shield layer 5 can be 55% or more and 65% or less. Similarly, in a cross-sectional view perpendicular to the cable length direction, the proportion of the total of the cross-sectional areas of the second metal wires 52 with respect to the cross-sectional area of the entire shield layer 5 can be 35% or more and 45% or less. In other words, in a cross-sectional view perpendicular to the cable length direction, the ratio S1 / S2 of the cross-sectional area S1 obtained by adding the cross-sectional areas of the plurality of first metal wires 51 each other and the cross-sectional area S2 obtained by adding the cross-sectional areas of the plurality of second metal wires 52 each other can be set to 1.22 (55 / 45) or more and 1.86 (65 / 35) or less. Thereby, the entire shield layer 5 is made soft to easily bend the cable 1, and it is easy to maintain the shape of the shield layer 5 at the time of forming processing into a desired shape, and the end processing of the cable 1 becomes easy.

[0042] (Action and Effect of Embodiment)

[0043] As explained above, in the electric cable 1 according to the present embodiment, the shield layer 5 is composed of a braided shield that is braided in a crisscross manner with a plurality of first metal wires 51 composed of aluminum or an aluminum alloy and a plurality of second metal wires 52 composed of copper or a copper alloy. By providing such a shield layer 5, it is possible to achieve an electric cable 1 that is lightweight, easy to lay, and in which it is difficult for the metal wires that make up the shield layer 5 to break even if the electric cable 1 is bent.

[0044] (SUMMARY OF EMBODIMENTS)

[0045] Next, with respect to the technical idea grasped from the above-described embodiments, reference signs and the like in the embodiments are cited. However, each symbol and the like in the following description does not limit the constituent elements in the claims to the components and the like specifically shown in the embodiments.

[0046] [1] An electric cable (1) comprising: an electric cable core (3) having one or more electric wires (2); a shield layer (5) covering the periphery of the electric cable core (3); and a sheath (6) covering the periphery of the shield layer (5),

[0047] The shield layer (5) is composed of a braided shield that is braided in a crisscross manner with a plurality of first metal wires (51) composed of aluminum or an aluminum alloy and a plurality of second metal wires (52) composed of copper or a copper alloy.

[0048] [2] The electric cable (1) according to [1], wherein the cross-sectional area of the first metal wire (51) is larger than the cross-sectional area of the second metal wire (52).

[0049] [3] The electric cable (1) according to [2], wherein the cross-sectional area of the first metal wire (51) is 1.5 times or more and 2.0 times or less of the cross-sectional area of the second metal wire (52).

[0050] [4] The electric cable (1) according to any one of [1] to [3], wherein the total proportion of the cross-sectional area of the first metal wire (51) in the cross-sectional area of the shield layer (5) is larger than the total proportion of the cross-sectional area of the second metal wire (52).

[0051] [5] The electric cable (1) according to any one of [1] to [4], wherein the first metal wire (51) is composed of a soft material, has a tensile strength of 90 MPa or more, an elongation of 10% or more, and an electrical conductivity of 60% or more.

[0052] [6] The electric cable (1) according to any one of [1] to [5], wherein the second metal wire (52) is composed of a soft material, has a tensile strength of 200 MPa or more, an elongation of 10% or more, and an electrical conductivity of 98% or more.

[0053] The above describes embodiments of the present application, but the above-described embodiments do not limit the application covered by the claims. Note that not all combinations of features described in the embodiments are essential to the means for solving the problems of the application. Further, the present application can be implemented appropriately without departing from the spirit of the present application.

Claims

1. A cable having: A cable core, which has one or more wires, A shielding layer that covers the area around the cable core, and A protective sleeve that covers the area around the shielding layer; The shielding layer is composed of a braided shielding element, which is formed by interlacing multiple first metal wires made of aluminum or aluminum alloy and multiple second metal wires made of copper or copper alloy. In a cross-sectional view perpendicular to the length of the cable, the ratio S1 / S2, which is the sum of the cross-sectional areas of the plurality of first metal wires, to the sum of the cross-sectional areas of the plurality of second metal wires, is 1.22 or more and 1.86 or less.

2. The cable according to claim 1, wherein, The cross-sectional area of ​​the first metal wire is larger than that of the second metal wire.

3. The cable according to claim 2, wherein, The cross-sectional area of ​​the first metal wire is more than 1.5 times and less than 2.0 times the cross-sectional area of ​​the second metal wire.

4. The cable according to any one of claims 1 to 3, wherein, A press-wound tape is spirally wound around the cable core, and the shielding layer is arranged to cover the area around the press-wound tape.

5. The cable according to any one of claims 1 to 3, wherein, The second metal wire is made of soft material, with a tensile strength of 200 MPa or more, an elongation of 10% or more, and a conductivity of 98% or more.

6. The cable according to claim 4, wherein, The second metal wire is made of soft material, with a tensile strength of 200 MPa or more, an elongation of 10% or more, and a conductivity of 98% or more.

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