Communication wires, terminal wires and wire harnesses

Abstract

To provide an electric wire for communication, an electric wire with a terminal and a wire harness which have strength suitable for arrangement in an automobile and transfer characteristics corresponding to communication with Ethernet.SOLUTION: An electric wire 1A for communication includes a twisted pair wire 2 obtained by twisting a pair of insulated wires 11A and 11B, and a sheath 12A which covers the outer periphery of the twisted pair wire 2 and is formed of a polyolefin-based resin. The insulated wires 11A and 11B have conductors 111 which are composed of a twisted wire obtained by twisting element wires 1111, and have tensile strength of 750 MPa or more and a cross-sectional area of 0.35 mm2, and insulated coatings 112 which cover the outer peripheries of the conductors 111 and are formed of a polyolefin-based resin. As for the electric wire 1A for communication, a twisting direction of the element wires 1111 in the conductors 111 and twisting directions of the insulated wire 11A and the insulated wire 11B are opposite to each other, and a characteristic impedance is within 100 Ω±10 Ω.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a communication electric wire, an electric wire with a terminal, and a wire harness. [Background technology]

[0002] An invention of an electric wire used for Ethernet (registered trademark) communication in an automobile is, for example, the electric wire disclosed in Patent Document 1. The communication electric wire disclosed in Patent Document 1 is made by twisting together electric wires each including a conductor having a tensile strength of 400 MPa or more and a breaking elongation of 7% or more, and an insulating coating that covers the conductor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-188431 A Summary of the Invention [Problem to be solved by the invention]

[0004] Generally, when considering the crimping of a terminal to an electric wire, it is known that the tensile strength of the conductor after crimping is lower than the tensile strength before crimping. This is because when the electric wire is crimped to the terminal, the cross-sectional area of ​​the conductor is reduced, and the conductor is stretched and deformed, resulting in a deterioration in tensile strength. In the case of electric wires for automobiles, it is desirable for the conductor to withstand a force of 50N, as stated in the minimum tensile strength of the terminal crimped part shown in Table 2 on page 3 of JASO D 616 (issued in 2011), a standard of the Society of Automotive Engineers of Japan. Therefore, when the electric wire before the terminal is crimped is designed in accordance with JASO D 616, it is desirable for it to be manufactured so that it has a tensile strength that can withstand a force of 50N after crimping.

[0005] However, there is a concern that the communication electric wire disclosed in Patent Document 1 does not satisfy the minimum tensile strength of the terminal crimped portion. Therefore, in order to satisfy the minimum tensile strength, it is necessary to increase the tensile strength of the conductor.

[0006] However, if the tensile strength of the conductor is increased to meet the minimum tensile strength, the conductor will become harder, which may cause the wire twist to become disordered or to develop twist tendencies. If the conductor twist opens due to such disorder or twist tendencies, the characteristic impedance will change, adversely affecting the transmission characteristics stipulated by the Ethernet standard, so measures are required to prevent the transmission characteristics from deteriorating.

[0007] The present invention has been made in consideration of the above, and aims to provide a communication wire, a terminal-equipped wire, and a wire harness that have strength suitable for wiring in an automobile and transmission characteristics compatible with Ethernet communication. [Means for solving the problem]

[0008] In order to solve the above-mentioned problems and achieve the object, a communication electric wire according to one aspect of the present invention includes a twisted pair wire formed by twisting a plurality of insulated electric wires, and a sheath covering an outer periphery of the twisted pair wire, each of the insulated electric wires being formed by twisting element wires, having a tensile strength of 750 MPa or more, and a cross-sectional area of ​​0.35 mm 2 or below and an insulating coating covering the outer periphery of the conductor, wherein the stranding direction of the wires is opposite to the stranding direction of the insulated wire, and the communication electric wire has a characteristic impedance within the range of 100Ω±10Ω.

[0009] In the communication electric wire according to one aspect of the present invention, the conductor may have a breaking elongation of 1% or more and less than 4%.

[0010] In the communication electric cable according to one aspect of the present invention, the wire may be made of a copper alloy containing tin, and the concentration of tin may be 0.6 mass % or more and 0.8 mass % or less.

[0011] An electric wire with terminal according to one aspect of the present invention is an electric wire with terminal including a terminal and any one of the communication electric wires described above joined to the terminal.

[0012] A wire harness according to one aspect of the present invention includes the electric wire with terminal described above and is arranged in an automobile. Effect of the Invention

[0013] According to the present invention, it is possible to provide a communication electric wire, an electric wire with terminal, and a wire harness that have strength suitable for wiring in an automobile and transmission characteristics compatible with Ethernet communication. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is a cross-sectional view of a communication wire according to an embodiment. [Diagram 2] FIG. 2 is a cross-sectional view of a communication wire having a solid sheath. [Diagram 3] FIG. 3 is a diagram showing how to twist a twisted pair of wires. [Figure 4] FIG. 4 is a diagram showing the measurement results of the transmission characteristics of a communication cable. [Diagram 5] FIG. 5 is a cross-sectional view of a communication wire according to a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings. Note that the present invention is not limited to the embodiment described below. In addition, in the description of the drawings, the same or corresponding elements are appropriately assigned the same reference numerals. Furthermore, it should be noted that the drawings are schematic, and the dimensional relationship of each element may differ from the actual one. There may also be parts in which the dimensional relationship and ratio are different between the drawings.

[0016] 1 is a cross-sectional view of a communication electric wire 1A according to one embodiment of the present invention. The communication electric wire 1A has a characteristic impedance in the range of 100Ω±10Ω. The communication electric wire 1A is wired, for example, in an automobile and used for communication in the automobile in accordance with the Ethernet (registered trademark) standard.

[0017] The communication electric wire 1A is composed of an insulated electric wire 11A, an insulated electric wire 11B, and a sheath 12A. The insulated electric wire 11A and the insulated electric wire 11B are twisted together to form a twisted pair wire 2, and the twisted pair wire 2 is covered with a sheath 12A.

[0018] (Insulated Wire) The insulated wire 11A is composed of a conductor 111 and an insulating coating 112. The conductor 111 is, for example, a compressed conductor formed by compressing seven S-twisted wires 1111 and annealing the compressed conductor. The conductor 111 is an example of a twisted wire. The conductor 111 may be Z-twisted instead of S-twisted. Regarding annealing of this compressed conductor, the heating temperature, heating time, temperature holding time after heating, and cooling time are set so that the tensile strength of the compressed conductor is in the range of 600 MPa to 1200 MPa and the breaking elongation is 1% or more and 7% or less. The tensile strength of the compressed conductor is preferably 750 MPa or more. The radial cross-sectional area of ​​the conductor 111 is 0.05 mm 2 (0.05sq) or more and 0.35mm 2 (0.35 sq.) or less. From the viewpoint of reducing weight and reducing diameter when wired in an automobile, the cross-sectional area of ​​the conductor 111 in the radial direction is set to 0.22 mm 2 (0.22sq), preferably less than 0.13mm 2 It is more preferable that the thickness of the wires 1111 is 0.13 sq. Note that the number of wires 1111 constituting the conductor 111, which is a stranded wire, is not limited to seven, and may be any other number.

[0019] The wire 1111 is made of a copper alloy containing tin. The concentration of tin in the wire 1111 is preferably 0.4% by mass or more and 0.8% by mass or less, and more preferably 0.6% by mass or more and 0.8% by mass or less. The wire 1111 may also be made of a copper alloy containing 1% by mass or more and 4% by mass or less of silver. The insulated wire 11B has the same configuration as the insulated wire 11A, and therefore a description thereof will be omitted.

[0020] The insulating coating 112 is preferably made of a resin having a low dielectric constant, and is formed of a resin based on a polyolefin resin such as PE (polyethylene), EVA (ethylene vinyl acetate), or PP (polypropylene). In this embodiment, the insulating coating 112 is formed of a halogen-free material based on PP to which a flame retardant and an antioxidant are added. The thickness of the insulating coating 112 is formed so that the characteristic impedance of the communication electric wire 1A is 100Ω±10Ω. The hardness of the insulating coating 112 is preferably such that it does not cause plastic deformation when the communication electric wires 1A and 1B are arranged in an automobile and the temperature rises. For example, in the communication electric wire 1A having a pipe-shaped sheath 12A, the hardness of the insulating coating 112 is preferably equal to that of the sheath 12A.

[0021] (sheath) The sheath 12A contributes to protecting the twisted pairs 2, stabilizing the twisting of the twisted pairs 2, and ensuring a distance between the twisted pairs 2 and the surrounding environment. The sheath 12A is formed in a hollow pipe shape. The sheath 12A is preferably formed of a resin based on a polyolefin resin. In this embodiment, the sheath 12A is formed of a halogen-free material based on a polyolefin resin to which a flame retardant and an antioxidant are added. In addition, inside the inner surface of the hollow sheath 12A, in a cross section along the radial direction of the communication electric wire 1A, the ratio of the space excluding the insulated electric wires 11A and 11B to the area inside the inner surface of the sheath 12A is called the void ratio, and the void ratio is preferably 8% or more and 30% or less.

[0022] The sheath protecting the twisted pair wires 2 may be a solid sheath that is not hollow, instead of the pipe-shaped sheath 12A shown in Fig. 1. Fig. 2 is a cross-sectional view of a communication electric wire 1B having a solid sheath 12B. Also, a tape or the like may be interposed between the twisted pair wires 2 and the sheaths 12A and 12B.

[0023] (twisted pair wire) 3 is a diagram showing a method of twisting the twisted pair wire 2. The twisted pair wire 2 is a twisted wire obtained by twisting the insulated electric wires 11A and 11B with a double twist buncher type twisting machine. In this embodiment, the twisted pair wire 2 is obtained by twisting the insulated electric wires 11A and 11B with a Z twist, which is opposite to the twist direction of the conductor 111, which is an S twist. The pitch of the twisted pair wire 2 is preferably 12 mm to 35 mm, and more preferably 16 mm to 30 mm. When the conductor 111 is Z twisted, the insulated electric wires 11A and 11B are twisted with an S twist, which is opposite to the twist direction of the conductor 111.

[0024] However, when insulated electric wires 11A and 11B are simply twisted together, insulated electric wires 11A and 11B are twisted when they are twisted together, and this twist creates an untwisting force, making twisted pair 2 prone to coming apart.

[0025] Therefore, in this embodiment, while insulated electric wires 11A and 11B are twisted and rotated together in a direction opposite to the rotational direction of the twisting (i.e., a rotational direction that reduces the twisting of insulated electric wires 11A and 11B due to the twisting), a so-called twist-back is performed to prevent twisting.

[0026] Here, the ratio Y / X of the twisting rotation angle X to the twisting rotation angle Y is called the twisting ratio. That is, when the insulated electric wires 11A and 11B are not twisted at all and the insulated electric wires 11A and 11B are in a twisted state, the twisting ratio is 0%, and when the insulated electric wires 11A and 11B are twisted at all and the insulated electric wires 11A and 11B are not twisted at all, the twisting ratio is 100%. In this embodiment, the twisting ratio of the twisted pair wire 2 is 100%. By setting the twisting ratio to 100%, the insulated electric wires 11A and 11B are less likely to come apart. The twisting ratio is not limited to 100%, but may be in the range of 100%±10%.

[0027] (evaluation) The communication electric wire 1A for evaluation was prepared by changing the radial cross-sectional area of ​​the conductor 111, the pitch of the twisted pair wire 2, and the twist direction of the twisted pair wire 2, and the transmission characteristics were evaluated. All the communication electric wires 1A prepared for evaluation had a pipe-shaped sheath 12A with a diameter of 3.2 mm, and the wires 1111 were formed of a copper alloy in which electric copper with a purity of 99.9% or more was mixed with tin at a concentration of 0.7% by mass, and were annealed to have a breaking elongation of 2.5% and a tensile strength of 800 MPa. The communication electric wires 1A for evaluation had the twist of the conductor 111 S-twisted with a pitch of 15 mm, and the radial cross-sectional areas of the conductor 111 were three types, 0.13 sq, 0.22 sq, and 0.08 sq.

[0028] In the communication electric wire 1A in which the radial cross-sectional area of ​​the conductor 111 is 0.13 sq, the diameter of the conductor 111 is 0.45 mm, in the communication electric wire 1A in which the radial cross-sectional area of ​​the conductor 111 is 0.22 sq, the diameter of the conductor 111 is 0.55 mm, and in the communication electric wire 1A in which the radial cross-sectional area of ​​the conductor 111 is 0.08 sq, wires 1111 having a diameter of 0.12 mm are twisted together, and the diameter of the conductor 111 is 0.36 mm.

[0029] The thickness of the insulating coating 112 in the communication electric wire 1A for evaluation was adjusted so that the characteristic impedance, together with the thickness of the sheath 12A, would be within the range of 100Ω±10Ω, and was set to 0.2 mm for the communication electric wire 1A in which the radial cross-sectional area of ​​the conductor 111 was 0.13 sq, 0.24 mm for the communication electric wire 1A in which the radial cross-sectional area of ​​the conductor 111 was 0.22 sq, and 0.17 mm for the communication electric wire 1A in which the radial cross-sectional area of ​​the conductor 111 was 0.08 sq. Note that for the communication electric wire 1A in which the radial cross-sectional area of ​​the conductor 111 was 0.13 sq, the thickness of the sheath 12A was set to 0.75 mm.

[0030] For the evaluation of the transmission characteristics, 10m of each of the communication cables 1A for evaluation was taken, and the S-parameters were measured using an E5071C ENA vector network analyzer from Keysight Technologies, Inc. Among the measured S-parameters, Sdc11 and Sdc22 are called reflection mode conversion, and Sdc12 and Sdc21 are called transmission mode conversion. Figure 4(a) shows an example of the measurement result of reflection mode conversion, and Figure 4(b) shows an example of the measurement result of transmission mode conversion. The line L1 shown in Figure 4(a) and the line L2 shown in Figure 4(b) are the evaluation criteria stipulated in the 100BASE-T1 Ethernet standard. In the evaluation of communication cable 1A, the minimum value of (criteria) - (waveform) was considered as the margin, and if the margin was 10dB or more, it was evaluated as "◎", if the margin was less than 10dB and 5dB or more, it was evaluated as "○", if the margin was less than 5dB and 0dB or more, it was evaluated as "×", and if the margin was negative, it was evaluated as "NG". Also, ◯ is a worse evaluation result than ◎, × is a worse evaluation result than ○, and NG is a worse evaluation result than ×, and the worse evaluation result of the reflection mode conversion evaluation result or the transmission mode conversion evaluation result was regarded as the final evaluation result.

[0031] Of the communication electric wires 1A used for evaluation, the evaluation results of the communication electric wires 1A having a radial cross-sectional area of ​​conductor 111 of 0.13 sq are shown in Table 1, the evaluation results of the communication electric wires 1A having a radial cross-sectional area of ​​conductor 111 of 0.22 sq are shown in Table 2, and the evaluation results of the communication electric wires 1A having a radial cross-sectional area of ​​conductor 111 of 0.08 sq are shown in Table 3.

[0032] [Table 1]

[0033] [Table 2]

[0034] [Table 3]

[0035] As shown in Tables 1, 2, and 3, when the twist direction of the twisted pair 2 is the same as the twist direction of the conductor 111, the evaluation result is × or NG. On the other hand, when the twist direction of the twisted pair 2 is opposite to the twist direction of the conductor 111, the margin with respect to the criteria is large, and an evaluation result of ◎ or ○ is obtained, and the transmission characteristics are better than when the twist direction of the twisted pair 2 is the same as the twist direction of the conductor 111.

[0036] Furthermore, the communication electric wire 1A was evaluated for the strength of the twist tendency of the twisted pair 2. In the evaluation of the twist tendency, the radial cross-sectional area of ​​the conductor 111, the pitch of the twisted pair 2, and the twist direction of the twisted pair 2 were changed and the evaluation was performed in a state in which the sheath 12A was not provided. The twisted pair 2 for evaluation had the same configuration as the twisted pair 2 provided in the communication electric wire 1A for evaluation described above.

[0037] For the evaluation of twisting tendency, 2 m of the twisted pair 2 was sampled, tension was applied to the sampled twisted pair 2, and both ends were held and then gradually brought closer together for evaluation. If the twisted pair 2 has a twisting tendency, as the ends are brought closer together, the twisted pair 2 will become twisted as the ends approach each other. During this process, the number of rotations of the twisted pair 2 as it is twisted was counted, and if the number of rotations was 6 rotations or less, it was evaluated as "○", if the number of rotations was more than 6 rotations but not more than 9 rotations, it was evaluated as "△", and if the number of rotations was more than 9 rotations, it was evaluated as "×".

[0038] Of the twisted pair wires 2 used for evaluation, the evaluation results of the twisted pair wire 2 in which the radial cross-sectional area of ​​the conductor 111 was 0.13 sq are shown in Table 4, the evaluation results of the twisted pair wire 2 in which the radial cross-sectional area of ​​the conductor 111 was 0.22 sq are shown in Table 5, and the evaluation results of the twisted pair wire 2 in which the radial cross-sectional area of ​​the conductor 111 was 0.08 sq are shown in Table 6.

[0039] [Table 4]

[0040] [Table 5]

[0041] [Table 6]

[0042] According to the evaluation results in Tables 4 to 6, as the diameter of conductor 111 increases, the rigidity increases, and thus twisting tends to occur. However, by increasing the pitch, twisting can be suppressed.

[0043] (Wire harness) In this embodiment, a terminal-attached electric wire is formed by joining a crimp terminal to the conductor 111 of the insulated electric wire 11A and the conductor 111 of the insulated electric wire 11B. The crimp terminal of the terminal-attached electric wire may be inserted into a connector housing (not shown) to form a connector-attached electric wire. A terminal-attached electric wire including the crimp terminal and the communication electric wire 1A is bundled with other electric wires and inserted into a connector to form a wire harness. This wire harness is arranged in, for example, an automobile.

[0044] [Variations] Although the embodiment of the present invention has been described above, the present invention is not limited to the above-mentioned embodiment and can be implemented in various other forms. For example, the above-mentioned embodiment may be modified as follows to implement the present invention. The above-mentioned embodiment and the following modifications may be combined with each other. The present invention also includes a configuration in which the components of the above-mentioned embodiments and modifications are appropriately combined. Further effects and modifications can be easily derived by a person skilled in the art. Therefore, the broader aspects of the present invention are not limited to the above-mentioned embodiment and modifications, and various modifications are possible.

[0045] Fig. 6 is a diagram showing a modified example of the communication electric wire. The communication electric wire 1B shown in Fig. 5 differs from the communication electric wire 1A in that it has an insulating coating 112A instead of the insulating coating 112. The insulating coating 112A is formed of a resin whose base material is a polyolefin resin. It differs in that the insulating coating 112 is a pipe type, whereas the insulating coating 112A is a solid type. [Explanation of symbols]

[0046] 1A, 1B communication wire 2 twisted pair 11A, 11B insulated wire 12A sheath 111 Conductor 112 Insulating coating 1111 Wire

Claims

1. A twisted pair wire formed by twisting a plurality of insulated electric wires; a sheath formed of a polyolefin resin covering an outer periphery of the twisted pair wire; having Each of the insulated wires is formed by twisting a Cu-Sn alloy wire, has a tensile strength of 750 MPa or more, and a cross-sectional area of ​​0.35 mm ２ A conductor as described below, and an insulating coating formed of a polyolefin resin that covers the outer periphery of the conductor; having The stranding direction of the wires is opposite to the stranding direction of the insulated wires, The characteristic impedance is within the range of 100Ω±10Ω. Communication wire.

2. The conductor has a breaking elongation of 1% or more and less than 4%.

2. The communication cable according to claim 1.

3. The wire has a tin concentration of 0.6 mass % or more and 0.8 mass % or less.

3. The communication cable according to claim 1 or 2.

4. The terminals and The communication wire according to claim 1 , which is joined to the terminal; A terminal-attached electric wire comprising:

5. A wire harness comprising the electric wire with terminal according to claim 4 and arranged in an automobile.

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