electric wire

Abstract

To provide an electric wire capable of preventing an element wire for transmitting an electrical signal from being cut.SOLUTION: An electric wire includes: at least one inner stranded wire 10 obtained by stranding a plurality of inner element wires 11; at least one outer element wire 21 being a conductor and having a diameter larger than that of the inner element wire 11; a plurality of outer stranded wires 20 stranded to arrange the inner stranded wire 10 in the inside; and a coating 30 covering the periphery of the plurality of outer stranded wires 20. The outer stranded wire 20 arranged in the outer periphery of the inner stranded wire 10 includes an outer element wire 21 having a diameter larger than that of the inner element wire 11; and a force easily acting on the outer element wire 21 of the outer stranded wire 20 arranged on the outside close to the coating and hardly acting on the inner element wire 11 of the inner stranded wire 10 arranged in the inside apart from the coating can prevent the inner element wire 11 of the inner stranded wire 10 for transmitting an electrical signal from being cut.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an electric wire. [Background technology]

[0002] Known electric wires that can be wound up, unwound, or bent are used in automobiles, elevators, robots, wind turbines for wind power generation, etc. Known electric wires have a configuration including a plurality of secondary strands formed by twisting together a plurality of primary strands, each of which is made up of strands of element wires that transmit a plurality of electrical signals, and a coating that covers the plurality of secondary strands (see, for example, Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-140006 [Patent Document 2] Japanese Patent Application Publication No. 2018-190516 Summary of the Invention [Problem to be solved by the invention]

[0004] In the case of an electric wire having the above-described configuration, there is a problem in that the wires are easily broken when the covering is removed to expose the secondary stranded wire. Specifically, when the covering is removed, force is likely to act on the wires located on the outer periphery of the secondary stranded wire, causing the wires to easily break.

[0005] The present invention has been made to solve the above-mentioned problems, and has an object to provide an electric wire in which the wires that transmit electric signals are difficult to break. [Means for solving the problem]

[0006] In order to achieve the above object, the present invention provides the following means. The electric wire of the present invention includes at least one inner stranded wire formed by twisting together a plurality of inner strands, a conductor having at least one outer strand having a diameter larger than that of the inner strand, a plurality of outer stranded wires twisted together with the inner stranded wire disposed inside, and a covering surrounding the plurality of outer stranded wires.

[0007] According to the electric wire of the present invention, the outer stranded wire arranged around the inner stranded wire has an outer strand having a larger diameter than the inner strands. When stripping the coating to expose the inner stranded wire and the outer stranded wire, force is likely to act on the outer stranded wire arranged on the outside closer to the coating, but force is less likely to act on the inner stranded wire arranged on the inside farther from the coating. [Effects of the Invention]

[0008] According to the electric wire of the present invention, the outer stranded wire arranged around the inner stranded wire has an outer strand having a larger diameter than the inner strand, which has the effect of making the strands that transmit electrical signals less likely to break. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 2 is a cross-sectional view illustrating the configuration of the electric wire. [Figure 2] FIG. 10 is a cross-sectional view illustrating the configuration of another electric wire having a different number of inner stranded wires. [Figure 3] FIG. 2 is a partial cross-sectional view illustrating the configuration of the inner stranded wire. [Figure 4] FIG. 4 is a schematic diagram illustrating the spring properties of the inner wire. [Figure 5] FIG. 2 is a schematic diagram illustrating a connection between an electric wire and a sensor. [Figure 6] FIG. 2 is a schematic diagram illustrating the connection between an electric wire and a connector. [Figure 7] 10A and 10B are schematic diagrams illustrating the formation of the inner stranded wire and the outer stranded wire. [Figure 8] 10 is a cross-sectional view illustrating the configuration of another electric wire having a different number of outer stranded wires. FIG. [Figure 9] 10 is a partial cross-sectional view illustrating the configuration of an outer stranded wire having a different number of outer strands. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0010] An electric wire 1 according to one embodiment of the present invention will be described with reference to Figs. 1 to 9. In this embodiment, the electric wire 1 is applied to an example in which it is connected to a sensor of an antilock braking system (hereinafter also referred to as ABS) of an automobile. Note that a cable having a plurality of electric wires 1 may be connected to the ABS sensor.

[0011] Fig. 1 is a cross-sectional view illustrating the configuration of an electric wire 1. As shown in Fig. 1, the electric wire 1 includes one inner stranded wire 10, six outer stranded wires 20, and a coating 30. Fig. 2 is a cross-sectional view illustrating another configuration of the electric wire 1. In this embodiment, an example in which one inner stranded wire 10 is provided in one electric wire 1 will be described, but multiple inner stranded wires 10 may be provided. For example, as shown in Fig. 2, three inner stranded wires 10 may be provided. When multiple inner stranded wires 10 are provided, the multiple inner stranded wires 10 may be twisted together.

[0012] Fig. 3 is a cross-sectional view illustrating the configuration of the inner stranded wire 10. As shown in Fig. 1, the inner stranded wire 10 is arranged in the center of the electric wire 1, and is surrounded by the outer stranded wire 20. As shown in Fig. 3, the inner stranded wire 10 is a stranded wire with a diameter D10 in which multiple inner wires 11 are twisted together. The diameter D10 is the diameter of a circle inscribed with the inner stranded wire 10.

[0013] In this embodiment, the inner stranded wire 10 has a configuration in which 42 inner wires 11 are twisted together. Specifically, seven inner wires 11 are twisted together, and seven of these twisted wires are twisted together to form the inner stranded wire 10. The number of inner wires 11 that make up the inner stranded wire 10 may be more or less than 42.

[0014] In this embodiment, the description will be given by taking an example in which the diameter D11 of the inner wire 11 is a metal wire of about 0.05 mm. The diameter D11 of the inner wire 11 may be smaller or larger than 0.05 mm.

[0015] The description will be given by taking an example in which the inner stranded wire 10 is a stranded wire having a thickness of 0.25 sq (also written as "square") to 0.3 sq. The thickness of the inner stranded wire 10 may be thinner than 0.25 sq or thicker than 0.3 sq. Here, "sq" is an index representing the thickness of the conductor in an electric wire as defined by the JIS standard.

[0016] The inner wire 11 is a metal wire that transmits electrical signals and is made of a material that has at least one of the following characteristics: higher springiness, higher elastic modulus, and higher bending durability than the outer wire 21 described later.

[0017] The springiness is the ease with which the inner wires 11 return to their original shape. For example, in the case of an inner stranded wire 10 in which linearly extending inner wires 11 are twisted together, the springiness is the ease with which the inner wires 11 return to the linear shape they had before being twisted.

[0018] The elastic modulus is the quotient of the stress, which is an applied external force, as the numerator and the strain caused by the stress as the denominator. In other words, it is the proportionality constant between stress and strain in the elastic deformation of the inner wire 11. The elastic modulus includes Young's modulus (also written as longitudinal elastic modulus or tensile elastic modulus), shear elastic modulus (also written as transverse elastic modulus), and bulk elastic modulus.

[0019] Bending durability is a property that indicates how difficult it is to break the inner wire 11 when repeatedly bent and stretched. When the inner wire 11 has high bending durability, it means that the inner wire 11 is difficult to break when repeatedly bent and stretched.

[0020] In this embodiment, the description will be given by taking an example in which the inner wire 11 is an alloy wire formed using a copper alloy containing tin. Note that the inner wire 11 may also be a hard copper wire that is not annealed after being formed by wire drawing.

[0021] As shown in Figure 1, the six outer stranded wires 20 are twisted together and surround the inner stranded wire 10. Adjacent outer stranded wires 20 are arranged in contact with each other. In other words, the six outer stranded wires 20 form a cylindrical wall around the inner stranded wire 10.

[0022] In this embodiment, one outer stranded wire 20 is composed of one outer element wire 21. In addition, this embodiment will be described as being applied to an example in which there are six outer stranded wires 20, but the number of outer stranded wires may be more or less than six.

[0023] In this embodiment, the diameter D21 of the outer wire 21 is larger than the diameter D11 of the inner wire 11. Furthermore, since one outer stranded wire 20 is made up of one outer wire 21, the diameter D21 of the outer wire 21 is larger than the diameter D10 of the inner stranded wire 10.

[0024] The outer wire 21 is a metal wire for transmitting electrical signals, formed using a material that has at least one of the following characteristics: lower springiness, lower elastic modulus, and lower bending durability than the inner wire 11.

[0025] In this embodiment, the description will be given by taking an example in which the outer wire 21 is a annealed copper wire. A annealed copper wire is a hard copper wire formed by wire drawing and then annealed. Using a annealed copper wire as the outer wire 21 makes it easier to reduce the manufacturing cost of the electric wire 1. Furthermore, in the hardening process described below, the outer wires 21 are more easily joined to each other. The outer wire 21 may also be an aluminum wire containing aluminum as a component.

[0026] The covering 30 is a member that covers the inner stranded wires 10 and the outer stranded wires 20. The covering 30 is made of an insulating resin material. Any known material can be used as the resin material, and there is no particular limitation.

[0027] Next, we will explain how to strip the coating 30 from the electric wire 1 having the above-described configuration. As shown in Fig. 1, when stripping the coating 30 to expose the inner stranded wires 10 and the outer stranded wires 20, force is likely to act on the outer stranded wires 20, which are located on the outside near the coating 30.

[0028] On the other hand, force is less likely to act on the inner stranded wire 10, which is disposed on the inside and away from the coating 30. The inner stranded wire 11 of the inner stranded wire 10 is disposed more inside the electric wire 1 than the outer stranded wire 21, and is less likely to be subjected to force, and is therefore less likely to be cut.

[0029] Fig. 4 is a schematic diagram illustrating the springiness of the inner wire 11. When the coating 30 is peeled off from the electric wire 1, the inner strand 10, which is made by twisting together the inner wires 11, experiences a force that causes the inner wires 11 to return to a straight shape due to its high springiness. For example, as shown in Fig. 4, as the inner wires 11 move away from the coating 30, a force acts to separate the inner wires 11 from each other. In other words, a force acts to cause the inner wires 11 to flare out.

[0030] 1, the electric wire 1 of this embodiment has an outer stranded wire 20 having an outer wire 21 with relatively low springiness disposed around an inner stranded wire 10 having inner wires 11 with relatively high springiness. The outer wire 21 has relatively low springiness and is therefore less likely to flare out even when the coating 30 is peeled off.

[0031] The outer wire 21 or outer stranded wire 20 arranged around it acts as a wall, making it difficult for the inner wires 11 of the inner stranded wire 10 to flare out. In other words, the inner wires 11 are confined inside the outer wire 21 or outer stranded wire 20 and are difficult to protrude to the outside.

[0032] Fig. 5 is a schematic diagram illustrating the connection between an electric wire 1 and a sensor 60. Fig. 6 is a schematic diagram illustrating the connection between an electric wire 1 and a connector 70. The electric wire 1 from which the coating 30 has been stripped is connected to the sensor 60 and the connector 70 as shown in Fig. 5 and Fig. 6. In Fig. 5, two electric wires 1 are connected by welding to two terminals 61, 61 of the sensor 60, respectively.

[0033] In Fig. 6, one electric wire 1 is connected by terminal crimping to a crimping portion 71 of one connector 70. The crimping portion 71 is a metal part having a U-shaped cross section with two side walls and a bottom surface, and is a part that is terminal-crimped to the electric wire 1 by bending the two side walls inward.

[0034] When the inner wire 11 is less likely to protrude outside the outer wire 21 or the outer stranded wire 20, the protruding inner wire 11 is less likely to come into contact with the circuit of the adjacent terminal 61, as shown in Fig. 5. In other words, it becomes less likely to cause a short circuit. Also, as shown in Fig. 6, the protruding inner wire 11 is less likely to protrude outside the crimping portion 71 and be crushed.

[0035] 7 is a schematic diagram illustrating the formation of the inner stranded wire 10 and the outer stranded wire 20. Before connecting the electric wire 1 to the sensor 60 and the connector 70, a step of hardening the exposed inner stranded wire 10 and outer stranded wire 20 is carried out.

[0036] In the hardening step, an anvil 100, a guide 110, and a horn 120 are used as shown in FIG.

[0037] The anvil 100 is a base on which the exposed inner stranded wire 10 and outer stranded wire 20 are placed. In this embodiment, a protrusion 101 is provided in the center of the top surface of the anvil 100, and the inner stranded wire 10 and outer stranded wire 20 are placed on either side of the protrusion 101.

[0038] The guide 110 is a member disposed on the upper surface of the anvil 100, and has an opening 111 in the center through which the protrusion 101 is inserted. The width of the opening 111 is formed to be wider than the width of the protrusion 101. A space is formed between the guide 110 and the protrusion 101 in which the inner stranded wire 10 and the outer stranded wire 20 are disposed.

[0039] The horn 120 is a member that sandwiches the inner stranded wire 10 and the outer stranded wire 20 between itself and the anvil 100, and is provided with two vibrating parts 121 that extend toward the anvil 100. The width of the vibrating parts 121 is narrower than the width from the side surface of the convex part 101 to the side surface of the opening 111. A gap G is formed between the vibrating parts 121 and the side surface of the opening 111.

[0040] The gap G is preferably large enough so that the outer strands 21 of the outer stranded wire 20 do not protrude from between the vibrating portion 121 and the side surface of the opening 111. In this embodiment, an example in which the gap G is 0.2 mm or more and 0.3 mm or less will be described.

[0041] When the inner stranded wire 10 and the outer stranded wire 20 are placed between the anvil 100, the guide 110, and the horn 120, the vibrating portion 121 of the horn 120 vibrates ultrasonically. Vibrations are transmitted from the tip of the vibrating portion 121 to the inner stranded wire 10 and the outer stranded wire 20. The outer strands 21 of the outer stranded wire 20 are bonded to each other by the vibration. In other words, the exposed inner stranded wire 10 and outer stranded wire 20 are solidified.

[0042] Furthermore, the presence of gap G prevents the tip of vibrating part 121 from coming into contact with the side surface of opening 111 when vibrating. Because diameter D21 of outer wire 21 is larger than diameter D11 of inner wire 11, gap G can be made wider, making it easier to prevent contact with guide 110 even when vibrating part 121.

[0043] In the electric wire 1 having the above configuration, the outer stranded wire 20 arranged around the inner stranded wire 10 has outer strands 21 with a larger diameter than the inner strands 11. When stripping the coating 30 to expose the inner stranded wire 10 and the outer stranded wire 20, force is likely to act on the outer strands 21 of the outer stranded wire 20 arranged on the outside closer to the coating 30, but force is less likely to act on the inner strands 11 of the inner stranded wire 10 arranged on the inside farther from the coating 30. Therefore, the inner wires 11 that transmit electrical signals are less likely to be cut when the coating 30 is stripped.

[0044] By twisting the outer stranded wires 20 adjacent to each other, it becomes easier to form a wall of the outer stranded wire 20 between the inner stranded wire 10 and the coating 30. By forming a wall of the outer stranded wire 20, it becomes difficult for force to act on the inner wires 11 of the inner stranded wire 10 when stripping off the coating 30.

[0045] Making the diameter of the outer stranded wire 20 larger than that of the inner stranded wire 10 makes it easier to form a wall of the outer stranded wire 20 between the inner stranded wire 10 and the coating 30. The formation of a wall of the outer stranded wire 20 makes it less likely that force will act on the inner wires 11 of the inner stranded wire 10 when stripping off the coating 30.

[0046] By reducing the springiness of the outer stranded wires 21 of the outer stranded wire 20 compared to the inner stranded wires 11 of the inner stranded wire 10, the outer stranded wires 21 are less likely to come out of the outer stranded wire 20 after the coating 30 is stripped off. Also, the inner stranded wires 11 are less likely to come out of the inner stranded wire 10 because they interfere with the outer stranded wires 20 arranged on the outer periphery of the inner stranded wire 10.

[0047] By increasing the spring property of the inner wire 11 compared to the outer wire 21, the inner wire 11 is less likely to be cut even if the outer wire 21 is cut due to bending of the electric wire 1. This makes it easier to maintain the function of transmitting electric signals of the electric wire 1.

[0048] By making the modulus of elasticity of the outer stranded wires 21 of the outer stranded wire 20 smaller than that of the inner stranded wires 11 of the inner stranded wire 10, the outer stranded wires 21 are less likely to come out of the outer stranded wire 20 after the coating 30 is stripped off. Also, because the inner stranded wires 11 interfere with the outer stranded wires 20 arranged on the outer periphery of the inner stranded wire 10, the inner stranded wires 11 are less likely to come out of the inner stranded wire 10.

[0049] By increasing the bending resistance of the inner wires 11 of the inner stranded wire 10 compared to the outer wires 21 of the outer stranded wire 20, the inner wires 11 are less likely to break even when the outer wires 21 are broken due to bending of the electric wire 1. In other words, it becomes easier to ensure the transmission of electric signals through the electric wire 1.

[0050] Fig. 8 is a cross-sectional view illustrating the configuration of another electric wire 1A having a different number of outer strands 21A in the outer stranded wire 20A. Fig. 9 is a partial cross-sectional view illustrating the configuration of an outer stranded wire 20A having a different number of outer strands 21A.

[0051] In the above-described embodiment, the electric wire 1 in which one outer stranded wire 20 has one outer strand 21 has been described as an example. However, the electric wire 1A in which one outer stranded wire 20A has seven outer strands 21A may also be used as shown in FIGS. 8 and 9.

[0052] As shown in Fig. 9, the outer stranded wire 20A is a twisted wire with a diameter D20A in which seven outer stranded wires 21A are twisted together. Diameter D20A is the diameter of a circle inscribed with the outer stranded wire 20A. Diameter D20A of the outer stranded wire 20A is larger than diameter D10 of the inner stranded wire 10. Furthermore, the inner pitch at which the inner stranded wires 11 in the inner stranded wire 10 are twisted together is smaller than the outer pitch at which the outer stranded wires 21A in the outer stranded wire 20A are twisted together.

[0053] In this embodiment, the outer wire 21A is a annealed copper wire, just like the outer wire 21. The outer wire 21A is a annealed copper wire having a diameter D21A. The diameter D21A of the outer wire 21A is larger than the diameter D11 of the inner wire 11.

[0054] By making the inner pitch of the inner stranded wire 10 smaller than the outer pitch of the outer stranded wire 20A, even if the outer stranded wire 21A of the outer stranded wire 20A is cut due to bending of the electric wire 1A, the inner stranded wire 11 of the inner stranded wire 10 is less likely to be cut.

[0055] The technical scope of the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. For example, in the above-described embodiments, the electric wire 1 is described as being used in an ABS of an automobile, but the electric wire can also be used in applications where it is wound up and unwound or bent, other than an ABS of an automobile. For example, the electric wire can also be used in applications such as elevators, robots, and wind turbines for wind power generation. [Explanation of symbols]

[0056] 1,1A...Electric wire, 10...Inner stranded wire, 11...Inner wire, 20,20A...Outer stranded wire, 21,21A...Outer wire, 30...Insulation

Claims

1. At least one inner stranded wire formed by twisting together a plurality of inner strands; a conductor having at least one outer strand having a diameter larger than that of the inner strand, the outer strand being a plurality of outer strands twisted together with the inner strand disposed therein; a covering covering the outer stranded wires; is established, The outer wire has lower springiness, or the ease with which it returns to its original shape, compared to the inner wire.

2. At least one inner stranded wire formed by twisting together a plurality of inner strands; a conductor having at least one outer strand having a diameter larger than that of the inner strand, the outer strand being a plurality of outer strands twisted together with the inner strand disposed therein; a covering covering the outer stranded wires; is established, The outer wire has a lower modulus of elasticity than the inner wire.

3. At least one inner stranded wire formed by twisting together a plurality of inner strands; a conductor having at least one outer strand having a diameter larger than that of the inner strand, the outer strand being a plurality of outer strands twisted together with the inner strand disposed therein; a covering covering the outer stranded wires; is established, The inner wire has higher bending durability than the outer wire.

4. The electric wire according to claim 1 , wherein the plurality of outer stranded wires are twisted around the inner stranded wire so as to be adjacent to each other.

5. The electric wire according to claim 1 , wherein the diameter of the outer stranded wire is larger than the diameter of the inner stranded wire.

6. The outer stranded wire is formed by twisting together a plurality of the outer element wires, The electric wire according to claim 1 , wherein an inner pitch at which the inner wires in the inner stranded wire are twisted together is smaller than an outer pitch at which the outer wires in the outer stranded wire are twisted together.

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