Communication Cables

Abstract

To provide an electric wire for communication which enables arrangement in an automobile by crimping a terminal.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 single wire or a twisted wire, and have tensile strength of 750 MPa or more, breaking elongation of 1% or more and less than 4% and a cross-sectional area of 0.35 mm2 or less, 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, there is a gap outside the insulation coatings 112 inside the inner face of the sheath 12A, 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 cable. [Background technology]

[0002] Inventions of electric wires used for communication inside an automobile include, for example, electric wires disclosed in Patent Documents 1 to 9. Patent Documents 1 to 8 disclose communication electric wires twisted together, each wire having a conductor with a tensile strength of 400 MPa or more and a breaking elongation of 7% or more and an insulating coating that covers the conductor. Patent Document 9 discloses an electric wire for information transmission inside a vehicle twisted together conductors that are Sn-Cu alloys, have a tensile strength of 350 MPa or more, and contain 0.2 to 1.5 wt% tin. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6164382 [Patent Document 2] Patent No. 6108057 [Patent Document 3] Patent No. 6447756 [Patent Document 4] Patent No. 6274346 [Patent Document 5] Patent No. 6485591 [Patent Document 6] JP 2019-114548 A [Patent Document 7] JP 2019-33101 A [Patent Document 8] JP 2017-188431 A [Patent Document 9] JP 2009-245742 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 wires disclosed in Patent Documents 1 to 9 do not satisfy the minimum tensile strength of the terminal crimped portion.

[0006] The present invention has been made in view of the above, and has an object to provide a communication electric wire that can be installed in an automobile by crimping a terminal. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems and achieve the object, a communication electric wire according to one aspect of the present invention comprises a twisted pair wire in which a plurality of insulated electric wires are twisted together, and a sheath formed of a polyolefin-based resin that covers the outer periphery of the twisted pair wire, and each of the insulated electric wires is composed of a single wire or a twisted wire, has a tensile strength of 750 MPa or more, a breaking elongation of 1% or more and less than 4%, and a cross-sectional area of ​​0.35 mm 2 and an insulating coating formed of a polyolefin resin that covers the outer periphery of the conductor, wherein there is an air gap on the outside of the insulating coating inside the inner surface of the sheath, and the characteristic impedance is within the range of 100 Ω ± 10 Ω.

[0008] The communication electric wire according to one aspect of the present invention is characterized in that, in a radial cross section, the ratio of the voids to a cross-sectional area inside the inner surface of the sheath is 10% or more and 30% or less.

[0009] In one aspect of the present invention, the electric wire for communication is characterized in that the twist ratio of the twisted pair wires is 100%±10%. Effect of the Invention

[0010] According to the present invention, it is possible to provide a communication electric wire having a strength suitable for wiring in an automobile when the terminal is crimped. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a cross-sectional view of a communication wire according to an embodiment. [Diagram 2] FIG. 2 is a diagram showing how to twist a twisted pair of wires. [Diagram 3] FIG. 3 is a diagram showing an example of wiring of communication wires in an automobile. [Figure 4] FIG. 4 is a cross-sectional view of a communication wire according to a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] 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.

[0013] 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.

[0014] 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.

[0015] (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 strands 1111 and then annealing the compressed conductor. The conductor 111 is an example of a stranded wire. With regard to annealing the 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 750 MPa or more and the breaking elongation is 1% or more and 4% or less. The radial cross-sectional area of ​​the conductor 111 is 0.35 mm 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.). The number of wires 1111 constituting the conductor 111, which is a twisted wire, is not limited to seven, and may be other numbers. Also, the conductor 111 may be a solid wire instead of a twisted wire.

[0016] The wire 1111 is made of a copper alloy containing tin. The concentration of tin in the wire 1111 is preferably 0.4 mass% or more and 0.8 mass% or less, and more preferably 0.6 mass% or more and 0.8 mass% or less. The wire 1111 may be a copper alloy containing 1 to 4 mass% of silver (e.g., Cu-1%Ag, Cu-2%Ag, Cu-4%Ag, etc.). The insulated wire 11B has the same configuration as the insulated wire 11A, and therefore a description thereof will be omitted.

[0017] 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.

[0018] (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 10% or more and 30% or less.

[0019] (twisted pair wire) 2 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 an insulated electric wire 11A and an insulated electric wire 11B by a double twist buncher type twisting machine.

[0020] 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.

[0021] 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.

[0022] 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 within the range of 100%±10%.

[0023] (evaluation) Examples 1 to 5 were prepared using the conductor 111 having the above-mentioned configuration. The tensile strength and breaking elongation of the prepared Examples 1 to 5 were measured in accordance with JIS Z 2241. In the measurement, the original rating distance was 250 mm, and the pulling speed was 50 / min. For comparison with the examples, Comparative Examples 1 and 2, which have compositions similar to those of the communication electric wire described in the patent document, were used as comparative examples, and the tensile strength and breaking elongation were measured in the same manner as in Examples 1 to 5.

[0024] In Examples 1 to 5, the wire 1111 is made of a copper alloy containing tin at a concentration of 0.7 mass % in electrolytic copper having a purity of 99.9% or more, and the cross-sectional area in the radial direction of the conductor 111 is 0.13 mm 2 (0.13sq) and then annealed.

[0025] In Comparative Examples 1 and 2, the wire 1111 is made of a copper alloy having an Fe concentration of 0.05 mass % or more and 2.0 mass % or less and a Ti concentration of 0.02 mass % or more and 1.0 mass % or less, and the cross-sectional area in the radial direction is 0.13 mm 2 (0.13sq).

[0026] The tensile strength and breaking elongation measurement results of Examples 1 to 5 and Comparative Examples 1 and 2 are shown in Table 1.

[0027] [Table 1]

[0028] In Comparative Example 1, the tensile strength is 554.01 MPa. The force that the conductor 111 of Comparative Example 1 can withstand is calculated by multiplying the tensile strength by the cross-sectional area: 554.01 MPa × 0.13 mm 2 = 72N. In Comparative Example 2, the tensile strength is 553.31 MPa. The force that the conductor 111 of Comparative Example 2 can withstand is calculated by multiplying the tensile strength by the cross-sectional area: 553.31 MPa × 0.13 mm 2 When this conductor was crimped to a terminal used for an electric wire for an automobile, in the cases of Comparative Examples 1 and 2, the minimum tensile strength was sometimes less than 50 N, which is specified in JASO D 616.

[0029] On the other hand, among Examples 1 to 5, even Example 5, which has the smallest tensile strength, has a tensile strength of 938.65 MPa. The force that the conductor 111 of Example 5 can withstand is calculated by multiplying the tensile strength by the cross-sectional area, which is 938.65 MPa×0.13 mm 2 = 120N. When this conductor 111 is crimped to a terminal used for an electric wire for an automobile, it can satisfy the minimum tensile strength specified in JASO D 616 (actual measured value is 80N or more), and meets the standard when used as an electric wire for an automobile.

[0030] In this embodiment, the porosity is set within the range of 10% to 30%, thereby making it possible to satisfy the characteristic impedance required by the standard of Ethernet (registered trademark). Also, by setting the porosity within the range of 10% to 30%, welding between the insulating coating 112 of the insulated wire 11A and the insulating coating 112 of the insulated wire 11B and between the insulating coating 112 and the sheath 12A can be prevented when the sheath 12A is formed.

[0031] Generally, the tensile strength is 0.13 mm at 80 N or more. 2 Since the (0.13sq) electric wire is made of a hard metal, if the twisting ratio is small, the stress when twisting is insufficient, Residual stress causes wire curl, making processing difficult. In this embodiment, by controlling the tension with the twist-back ratio set to 100%±10%, it is possible to suppress deformation of the communication electric wire 1A due to residual stress, and processability is improved compared to when the twist-back ratio is small.

[0032] In addition, to solve the above problems with static tension, the resistance to impact load is determined by toughness. Toughness is the ability of a material to deform without plastic deformation, and is defined as the amount of energy per volume that the material can absorb before breaking. Toughness corresponds to the area of ​​the curve in the stress-strain diagram, which can be roughly approximated as tensile strength x elongation / volume. In addition, in measuring the tensile strength of the conductor 111, if the length of the test piece is standardized, elongation [m] can be replaced with elongation [%], and if the change in volume is small, tensile strength [N] x elongation [%] can be used as toughness. In this embodiment, the toughness exceeds 0.8, and the wire has sufficient toughness as an electric wire.

[0033] (Wire harness) Next, an example in which the communication wire 1A is routed to an automobile will be described. Fig. 3 is a diagram showing an example in which the communication wire 1A according to the above-mentioned embodiment is routed to an automobile. The automobile 1000 shown in Fig. 3 is, for example, an automobile including a hybrid vehicle, an electric vehicle, or a fuel cell vehicle. The automobile 1000 has a routing structure 500.

[0034] The wiring structure 500 is a system that supplies power from a secondary battery BAT possessed by the automobile 1000 to electrical equipment and relays signals exchanged between an ECU (Electronic Control Unit) 600 that controls the electrical equipment and the electrical equipment. The wiring structure 500 has a plurality of electric connection boxes and a plurality of cables. The secondary battery BAT is a secondary battery that can be repeatedly charged and discharged. The voltage of the secondary battery BAT is, for example, 12V, and it is charged by an alternator (not shown) possessed by the automobile 1000 and supplies power to a plurality of electrical equipment. The position of the secondary battery BAT is not limited to the position shown in the figure, and it may be disposed at another position within the automobile 1000.

[0035] The wiring structure 500 has a plurality of cables, namely, a cable BW1, a cable BW2, a cable RW, a cable LW, a cable RW1, a cable LW1, a cable RW11, and a cable LW11. The cables RW, LW, RW1, LW1, RW11, and LW11 are cables having the above-mentioned communication electric wire 1A, and are examples of wire harnesses.

[0036] The wiring structure 500 has a plurality of electric junction boxes, including a distribution unit FM, an electric junction box FR, an electric junction box FL, an electric junction box MR, an electric junction box ML, an electric junction box RR, and an electric junction box RL. These electric junction boxes have terminals to which electric wires that connect electric components and the electric junction box to supply power to the electric components are connected, terminals to which communication wires 1A that connect electric components and the electric junction box to transmit and receive signals between the electric components are connected, a control unit that controls the power supply to the electric components, a relay circuit, a fuse, a switching circuit, a smoothing circuit, and the like.

[0037] The electrical components connected to the multiple electrical junction boxes of the wiring structure 500 include, for example, lighting devices such as headlamps, tail lamps, stop lamps, and turn lamps, devices around the driver's seat such as a display device, car audio, and an instrument panel, devices such as power windows, wipers, seat heaters, door locks, electric mirrors, rear defrosters, and rear wipers, actuators, various sensors, etc. In order to prevent the drawing from becoming too complicated, the multiple electrical components are not shown in FIG.

[0038] According to the wiring structure 500, communication in accordance with the Ethernet (registered trademark) standard can be performed between the ECU 600 and the electrical equipment via the electrical junction box and the above-mentioned cable.

[0039] [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.

[0040] Fig. 4 is a diagram showing a modified example of the communication electric wire. The communication electric wire 1B shown in Fig. 4 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]

[0041] 1A, 1B communication wire 2 twisted pair 11A, 11B insulated wire 12A sheath 111 Conductor 112 Insulating coating 500 Cable Structure 600 ECU 1000 Cars 1111 Wire BAT secondary battery BW1, BW2, RW1, LW1, RW11, LW11 cables FM distribution section FR, MR, RR, FL, ML, RL Electrical Junction Box

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 comprises: It is made of a single wire or a stranded wire, is made of a Cu-Sn alloy, has a tensile strength of 750 MPa or more, a breaking elongation of 1% or more and less than 4%, and has 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 A gap is provided on the outside of the insulating coating inside the inner surface of the sheath, The characteristic impedance is within the range of 100Ω±10Ω. Communication wire.

2. In a radial cross section, the ratio of the void to the cross-sectional area inside the inner surface of the sheath is 10% or more and 30% or less.

2. The communication cable according to claim 1.

3. The twist ratio of the twisted pair is 100%±10%.

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

Images