JP2022142635A - Electric wire for communication - Google Patents

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

The present invention relates to a communication wire.

Patent Documents 1 to 9, for example, disclose electric wires as inventions of electric wires used for communication in automobiles. Patent Documents 1 to 8 disclose communication electric wires obtained by twisting electric wires including a conductor having a tensile strength of 400 MPa or more and a breaking elongation of 7% or more and an insulating coating covering the conductor. . Patent Document 9 discloses an electric wire for in-vehicle information transmission in which a conductor made of an Sn—Cu alloy, having a tensile strength of 350 MPa or more and containing 0.2 to 1.5 wt% of tin is twisted together. It is

Japanese Patent No. 6164382 Japanese Patent No. 6108057 Japanese Patent No. 6447756 Japanese Patent No. 6274346 Japanese Patent No. 6485591 JP 2019-114548 A Japanese Patent Application Laid-Open No. 2019-33101 JP 2017-188431 A JP 2009-245742 A

Generally, when crimping a terminal onto an electric wire, it is known that the tensile strength of a conductor after crimping is lower than the tensile strength before crimping. This is because when the wire is crimped to the terminal, the wire is compressed, the cross-sectional area of the conductor is reduced, the wire is stretched and deformed, and the tensile strength is deteriorated. In the electric wire for automobiles, the conductor to which the terminal is crimped is listed in the minimum tensile strength of the crimped part of the terminal shown in Table 2 on page 3 of JASO D 616 (published in 2011), a standard of the Society of Automotive Engineers of Japan. As you can see, it is desirable to be able to withstand a force of 50N. Therefore, when the electric wire before the terminal is crimped is designed according to JASO D 616, it is desired that the electric wire be manufactured so as to have a tensile strength capable of withstanding a force of 50 N after crimping.

However, there is a concern that the communication wires disclosed in Patent Documents 1 to 9 do not satisfy the minimum tensile strength of the terminal crimping portion.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a communication wire that can be installed in a vehicle by crimping a terminal.

In order to solve the above problems and achieve the object, a communication wire according to one aspect of the present invention includes a twisted pair wire obtained by twisting a plurality of insulated wires and a polyolefin resin covering the outer periphery of the twisted pair wire. Each of the insulated wires is composed of a single wire or a stranded wire, has a tensile strength of 750 MPa or more, has a breaking elongation of 1% or more and less than 4%, and has a cross-sectional area of It has a conductor with a size of 0.35 mm ² or less and an insulating coating made of polyolefin resin that covers the outer periphery of the conductor, and there is a gap outside the insulating coating inside the inner surface of the sheath. , the characteristic impedance is within the range of 100Ω±10Ω.

A communication wire according to an aspect of the present invention is characterized in that, in a cross section in a radial direction, the ratio of the voids to the cross-sectional area inside the inner surface of the sheath is 10% or more and 30% or less.

According to one aspect of the present invention, the electric wire for communication is characterized in that the twist rate of the twisted pair wire is 100%±10%.

Advantageous Effects of Invention According to the present invention, it is possible to provide a communication electric wire having a strength suitable for wiring in an automobile in a state where a terminal is crimped.

FIG. 1 is a cross-sectional view of a communication wire according to an embodiment. FIG. 2 is a diagram showing how to twist a twisted pair wire. FIG. 3 is a diagram showing an example of wiring of communication wires to a vehicle. FIG. 4 is a cross-sectional view of a communication wire according to a modification.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In addition, this invention is not limited by embodiment described below. Moreover, in the description of the drawings, the same or corresponding elements are given the same reference numerals as appropriate. Furthermore, it should be noted that the drawings are schematic, and the dimensional relationship of each element may differ from the actual one. Even between the drawings, there are cases where portions with different dimensional relationships and ratios are included.

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

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

(Insulated wire)
11 A of insulated wires are comprised by the conductor 111 and the insulation coating 112. As shown in FIG. The conductor 111 is obtained by annealing a compressed conductor formed by compressing seven S-twisted strands 1111, for example. Conductor 111 is an example of a twisted wire. For the annealing performed on this compressed conductor, the tensile strength of the compressed conductor is 750 MPa or more, and the breaking elongation is 1% or more and 4% or less. Set the holding time and cooling time. Moreover, the cross-sectional area of the conductor 111 in the radial direction shall be 0.35 mm ² (0.35 sq) or less. From the viewpoint of weight reduction and diameter reduction when wiring in an automobile, it is preferable that the radial cross-sectional area of the conductor 111 is less than 0.22 mm ² (0.22 sq), and 0.13 mm ² (0.22 sq) or less. .13 sq) is more preferred. The number of strands 1111 constituting the conductor 111, which is a twisted wire, is not limited to seven, and may be another number. Also, the conductor 111 may be a single wire instead of a twisted wire.

The wire 1111 is made of a copper alloy containing tin. The concentration of tin in the wire 1111 is desirably 0.4% by mass or more and 0.8% by mass or less, more preferably 0.6% by mass or more and 0.8% by mass or less. Also, the wire 1111 may be a copper alloy containing 1 to 4% by mass of silver (for example, Cu-1%Ag, Cu-2%Ag, Cu-4%Ag, etc.). In addition, since the insulated wire 11B has the same configuration as the insulated wire 11A, the description thereof is omitted.

The insulating coating 112 is preferably made of a resin having a low dielectric constant, and is made 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 made of PP-based halogen-free material 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 wire 1A is 100Ω±10Ω. The hardness of the insulation coating 112 is preferably such that it does not undergo plastic deformation when the communication wires 1A and 1B are installed in an automobile and the temperature rises. It is preferable that the hardness of the insulating coating 112 is equivalent to that of the sheath 12A.

(sheath)
The sheath 12A contributes to protecting the twisted pair 2, stabilizing the twisted pair of the twisted pair 2, and ensuring the distance between the twisted pair 2 and the surrounding environment. The sheath 12A is formed in a hollow pipe shape. It is preferable that the sheath 12A is made of a resin having a polyolefin resin as a base material. In this embodiment, the sheath 12A is made of a halogen-free material based on a polyolefin-based resin to which a flame retardant and an antioxidant are added. Further, inside the inner surface of the hollow sheath 12A, the ratio of the space excluding the insulated wires 11A and 11B to the area inside the inner surface of the sheath 12A in the cross section along the radial direction of the communication wire 1A is defined as the gap. It is preferable that the porosity is 10% or more and 30% or less.

(twisted pair wire)
FIG. 2 is a diagram showing how the twisted pair wire 2 is twisted. The twisted pair wire 2 is a twisted wire obtained by twisting the insulated wire 11A and the insulated wire 11B with a double twist buncher type wire twister.

By the way, when the insulated wire 11A and the insulated wire 11B are twisted together, if the insulated wire 11A and the insulated wire 11B are simply twisted together, the insulated wire 11A and the insulated wire 11B are twisted in a twisted state. , the twisted pair wire 2 tends to come loose.

Therefore, in this embodiment, while twisting the insulated wire 11A and the insulated wire 11B, the rotation direction opposite to the twisting direction (that is, the twisting of the insulated wire 11A and the twisting of the insulated wire 11B due to twisting) The insulated wire 11A and the insulated wire 11B are each twisted and rotated in the direction of rotation to relax the twisting, that is, so-called twisting is applied to prevent twisting.

Here, the ratio Y/X between the twisting rotation angle X and the twisting rotation angle Y is referred to as the twisting ratio. That is, when the insulated wire 11A and the insulated wire 11B are not twisted at all, and the insulated wire 11A and the insulated wire 11B are twisted, the twist rate is 0%, and no twist is applied. , the value of the twist rate is 100% when there is no twist of the insulated wire 11A itself and no twist of the insulated wire 11B itself. In this embodiment, the twist rate of the twisted pair wire 2 is 100%. By setting the twist rate to 100%, the insulated wire 11A and the insulated wire 11B are less likely to come apart. The twist rate is not limited to 100%, and may be in the range of 100%±10%.

(evaluation)
Examples 1 to 5 were produced for the conductor 111 having the above configuration. Tensile strength and elongation at break were measured according to JIS Z 2241 for Examples 1 to 5 prepared. In the measurement, the original score distance was set to 250 mm, and the tensile speed was set to 50/min. For comparison with the examples, comparative examples 1 and 2 having compositions similar to those of the communication wire described in the patent document were used as comparative examples, and tensile strength and elongation at break were measured in the same manner as in examples 1 to 5. did.

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

In Comparative Examples 1 and 2, the strand 1111 has an Fe concentration of 0.05% by mass or more and 2.0% by mass or less, and a Ti concentration of 0.02% by mass or more and 1.0% by mass or less. It is a copper alloy and has a radial cross-sectional area of 0.13 mm ² (0.13 sq).

Table 1 shows the tensile strength and breaking elongation measurement results of Examples 1 to 5 and Comparative Examples 1 and 2.

In Comparative Example 1, the tensile strength is 554.01 MPa. The force that the conductor 111 of Comparative Example 1 can withstand is 554.01 MPa×0.13 mm ² =72 N when the tensile strength is multiplied by the cross-sectional area. In Comparative Example 2, the tensile strength is 553.31 MPa. The force that the conductor 111 of Comparative Example 2 can withstand is 553.31 MPa×0.13 mm ² =72 N when the tensile strength is multiplied by the cross-sectional area. When this conductor was crimped to a terminal used for electric wires for automobiles, in Comparative Examples 1 and 2, the minimum tensile strength stipulated in JASO D 616, 50 N, was sometimes reached.

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

Further, in this embodiment, by setting the porosity within the range of 10% to 30%, it is possible to satisfy the characteristic impedance required by the Ethernet (registered trademark) standard. In addition, by setting the porosity within the range of 10% to 30%, when forming the sheath 12A, the insulation coating 112 of the insulated wire 11A and the insulation coating 112 of the insulated wire 11B are welded, and the insulation coating 112 and the sheath Welding with 12A is avoided.

In general, an electric wire with a tensile strength of 80 N or more and a size of 0.13 mm ² (0.13 sq) is a hard metal.
Line curl due to residual stress occurs, making processing difficult. In the present embodiment, by managing the tension with the twist rate of 100%±10%, it is possible to suppress the deformation of the communication wire 1A due to the residual stress. improving.

In contrast to the above problem of static tension, resistance to impact load is defined by toughness. Toughness is the ability of a material to deform without plastically deforming and is defined as the amount of energy per volume that a material can absorb before breaking. The toughness corresponds to the area of the curve in the stress-strain diagram, which can be approximated as tensile strength x elongation/volume. In addition, in the measurement of the tensile strength of the conductor 111, if the length of the test piece is unified, the elongation [m] can be replaced with the elongation [%], and if the change in volume is small, the tensile strength [ N]×elongation [%] can be used as the toughness. In this example, the toughness exceeds 0.8, which is sufficient for electric wires.

(wire harness)
Next, an example in which the communication wire 1A is installed in an automobile will be described. FIG. 3 is a diagram showing an example in which the communication wire 1A according to the embodiment described above is installed in a vehicle. A vehicle 1000 shown in FIG. 3 is, for example, a vehicle including a hybrid vehicle, an electric vehicle, a fuel cell vehicle, or the like. Automobile 1000 has routing structure 500 .

The wiring structure 500 supplies electric power supplied from the secondary battery BAT of the automobile 1000 to the electrical components, and transmits and receives signals between the electrical components and an ECU (Electronic Control Unit) 600 that controls the electrical components. It is a relay system. The routing structure 500 has multiple electrical junction boxes and multiple cables. The secondary battery BAT is a secondary battery that can be repeatedly charged and discharged. The secondary battery BAT has a voltage of 12 V, for example, and is charged by an alternator (not shown) of the automobile 1000 to supply electric power to a plurality of electrical components. The position of secondary battery BAT is not limited to the position shown in the figure, and may be arranged at another position within automobile 1000 .

The wiring structure 500 has 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 as a plurality of cables. The cable RW, the cable LW, the cable RW1, the cable LW1, the cable RW11, and the cable LW11 are cables having the above-described communication wire 1A, and are examples of wire harnesses.

The wiring structure 500 has a distribution section FM, an electrical junction box FR, an electrical junction box FL, an electrical junction box MR, an electrical junction box ML, an electrical junction box RR, and an electrical junction box RL as a plurality of electrical junction boxes. These electrical junction boxes are composed of terminals that connect the electrical components and the electrical junction box to connect wires that supply power to the electrical components, and terminals that connect the electrical components and the electrical junction box to exchange signals with the electrical components. It has a terminal to which the communication wire 1A is connected, a control section for controlling power supply to electrical equipment, a relay circuit, a fuse, a switching circuit, a smoothing circuit, and the like.

The electrical components connected to the plurality of electrical connection boxes of the wiring structure 500 are, for example, lighting equipment such as headlamps, tail lamps, stop lamps, and turn lamps, display devices, car audio equipment, and driver's seats such as instrument panels. Peripheral devices, devices such as power windows, wipers, seat heaters, door locks, electric mirrors, rear defrosters, rear wipers, actuators, and various sensors. In addition, in order to prevent the drawing from becoming complicated, illustration of a plurality of electrical components is omitted in FIG.

According to the wiring structure 500, communication according to the Ethernet (registered trademark) standard can be performed between the ECU 600 and the electrical equipment via the electrical connection box and the cable described above.

[Modification]
Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and can be implemented in various other forms. For example, the present invention may be implemented by modifying the above-described embodiment as follows. It should be noted that the above-described embodiment and the following modified examples may be combined with each other. The present invention also includes configurations obtained by appropriately combining the constituent elements of the above-described embodiments and modifications. Further effects and modifications can be easily derived by those skilled in the art. Therefore, broader aspects of the present invention are not limited to the above-described embodiments and modifications, and various modifications are possible.

FIG. 4 is a diagram showing a modification of the communication wire. The communication wire 1B shown in FIG. 4 is different from the communication wire 1A in that the insulation coating 112 is replaced with an insulation coating 112A. The insulating coating 112A is made of a resin having a polyolefin resin as a base material. The insulating coating 112A is different in that the insulating coating 112 is of a pipe type, whereas the insulating coating 112 is of a solid type.

1A, 1B Communication wire 2 Twisted pair wire 11A, 11B Insulated wire 12A Sheath 111 Conductor 112 Insulating coating 500 Wiring structure 600 ECU
1000 Automobile 1111 Wire BAT Secondary battery BW1, BW2, RW1, LW1, RW11, LW11 Cable FM Distributor FR, MR, RR, FL, ML, RL Electrical connection box

Claims (3)

a twisted pair wire obtained by twisting a plurality of insulated wires;
a sheath made of a polyolefin resin that covers the outer periphery of the twisted pair wire;
has
each of the insulated wires,
A conductor composed of a single wire or a stranded wire, having a tensile strength of 750 MPa or more, an elongation at break of 1% or more and less than 4%, and a cross-sectional area of 0.35 mm ² or less, and a polyolefin covering the outer periphery of the conductor an insulating coating formed of a resin,
has
Inside the inner surface of the sheath, there is a gap outside the insulating coating,
A communication wire having a characteristic impedance within the range of 100Ω±10Ω. The electric wire for communication according to claim 1, wherein in a cross section in the radial direction, the ratio of the gap to the cross-sectional area inside the inner surface of the sheath is 10% or more and 30% or less. The electric wire for communication according to claim 1 or 2, wherein the twisted pair wire has a twist rate of 100% ± 10%.

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