JP2020024949A - Insulated wires and multi-core cables for vehicles - Google Patents

Abstract

To provide a coated cable for a vehicle with reduced costs while suppressing deterioration of flex resistance.SOLUTION: A coated cable 10 is obtained by coating a conductor 12 with an isolation layer 13 made of resin. In the coated cable 10, the conductor 12 is composed with a plurality of twisted wires 14, 15 twisted together, each of the twisted wires 14, 15 is composed with a plurality of strands 16, 17 twisted together, and a diameter of the strand 16 of the twisted wire 14 disposed at a center of the conductor 12 is larger than a diameter of the strand 17 composing the other twisted wire 15.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a covered electric wire and a multi-core cable for a vehicle.

A multi-core cable described in Patent Literature 1 is known. The conductor of the core electric wire of this multi-core cable is a stranded wire formed by twisting a plurality of strands of a copper alloy having a diameter of 0.08 mm. The conductor is composed of about 360 to 610 strands. The cross-sectional area of the conductor (total cross-sectional area of a plurality of strands) is 1.5 to 3.0 mm ² , and preferably 1.8 to ^2.5 mm ² .

JP 2014-220043 A

  SUMMARY OF THE INVENTION The present invention provides an insulated wire with reduced cost while suppressing a decrease in bending resistance, and a multi-core cable for a vehicle using the same.

The insulated wire of the present invention,
A covered wire in which a conductor is covered with a resin insulating layer,
The conductor is configured by twisting a plurality of stranded wires,
The stranded wire is configured by twisting a plurality of strands,
The diameter of the strand forming the stranded wire disposed at the center of the conductor is larger than the diameter of the strands forming the other stranded wires.

The multi-core cable for a vehicle according to the present invention includes:
Two said covered electric wires;
And a jacket covering the two covered electric wires.

  ADVANTAGE OF THE INVENTION According to this invention, the covered electric wire and the multicore cable for vehicles which reduced cost while suppressing the fall of bending resistance are provided.

It is a sectional view showing the multi-core cable for vehicles concerning a first embodiment of the present invention. It is a sectional view showing the multi-core cable for vehicles concerning a second embodiment of the present invention.

<Overview of Embodiment of the Present Invention>
First, an outline of an embodiment of the present invention will be described.
(1) The insulated wire
The conductor is a covered electric wire covered with a resin insulating layer,
The insulating layer covers the conductor with a thickness of 0.3 mm or more and 0.4 mm or less,
A cross-sectional area of the conductor is 1.5 mm ² or more and 3.0 mm ² or less;
The conductor is configured by twisting a plurality of stranded wires,
The stranded wire is configured by twisting a plurality of strands,
A diameter of the strand constituting the stranded wire disposed at the center of the conductor is larger than a diameter of the strand constituting the other stranded wire.

When configuring a stranded wire having a desired cross-sectional area, if the stranded wire is configured with a thick strand, the number of stranded wires is reduced as compared with the case where a stranded wire is configured with a thin strand, so that the cost can be reduced. . However, when a stranded wire is formed by a thick wire, the bending resistance of the stranded wire is reduced as compared with a case where a stranded wire is formed by a thin wire.
Then, according to the covered electric wire which concerns on the said structure, only the strand which comprises the stranded wire arrange | positioned at the center uses a strand thicker than another strand. As a result, the cost of the conductor can be reduced as compared with the case where the conductor is composed of only thin wires.
There is a concern that the use of a thick wire as a part of the wire constituting the conductor may reduce the bending resistance of the entire conductor. However, since the stranded wire composed of the thick strand is arranged at the center of the conductor, the reduction in the bending resistance of the entire conductor is suppressed. Thus, it is possible to reduce the cost while suppressing a decrease in the bending resistance of the entire conductor.

(2) In the covered electric wire having the configuration of the above (1),
The conductor is configured by twisting the seven strands,
Six of the stranded wires may be stranded around one of the stranded wires arranged at the center of the conductor.

  According to the coated electric wire having the above configuration, the stranded wires can be arranged in a balanced manner in the cross section of the coated electric wire, and the twisted structure of the conductor can be stably maintained.

(3) In the covered electric wire having the configuration of the above (2),
The diameter of the strand constituting one of the strands arranged at the center of the conductor is 0.1 mm or more, and the diameter of the strand constituting the other strand is 0.08 mm or less. There may be.

  According to the coated electric wire having the above-described configuration, it is easy to achieve both suppression of reduction in bending resistance and reduction in cost. If the diameter of the strand constituting one stranded wire arranged at the center of the conductor is less than 0.1 mm, it is difficult to reduce the cost. If the diameter of the wires constituting the other stranded wires is larger than 0.08 mm, it is difficult to suppress a decrease in bending resistance.

(4) In the covered electric wire having any one of the constitutions (1) to (3),
The insulating layer may be mainly composed of a copolymer of ethylene and an α-olefin having a carbonyl group.

  In the covered electric wire having the above configuration, the insulation layer has high bending resistance, and the covered electric wire has higher bending resistance.

(5) In the coated electric wire according to any of the above (1) to (4),
The outer diameter of the stranded wire having the largest outer diameter may be 1.5 times or less the outer diameter of the stranded wire having the smallest outer diameter.

  According to the coated electric wire having the above configuration, since the outer diameters of the plurality of stranded wires are uniform, the twisted stranded shape is stabilized.

(6) In the coated electric wire according to any one of the above (1) to (5),
The outer diameter of the stranded wire disposed at the center of the conductor may be 75% or more and 125% or less of the outer diameter of the other stranded wires.

  According to the coated electric wire having the above configuration, since the outer diameters of the plurality of stranded wires are uniform, the twisted stranded shape is stabilized.

(7) A multi-core cable for a vehicle,
Any of the above-described two covered electric wires of (1) to (6);
And a jacket covering the two covered electric wires.

  According to the multi-core cable for a vehicle having the above configuration, the wiring operation is easier than in the case where two covered electric wires are separately wired.

(8) In the multi-core cable for a vehicle according to the above (7),
A second conductor thinner than the conductor, a second insulating layer covering the second conductor, having a plurality of second wires each having a,
The second electric wires may be twisted together in pairs to form a pair-twisted second electric wire.

  According to the multi-core cable for a vehicle having the above configuration, the wiring operation is easier than in the case where the two covered electric wires and the twisted pair second electric wire are separately wired.

(9) The multi-core cable for a vehicle according to the above (8),
The two covered electric wires and the twisted pair second electric wire are stranded,
The jacket may cover the two twisted covered electric wires and the twisted paired second electric wire.

  According to the multi-core cable for a vehicle having the above configuration, the two insulated wires and the twisted pair second electric wire are twisted and the twisted state is covered with the jacket, so that the outer diameter of the multi-core cable is The shape becomes stable.

(10) The multi-core cable for a vehicle according to the above (9),
In the cross section orthogonal to the longitudinal direction of the multi-core cable, the two covered electric wires may be arranged point-symmetrically.

  According to the multi-core cable for a vehicle having the above configuration, the thick coated electric wires are arranged in a well-balanced cross section and have good symmetry, so that the multi-core cable is less likely to be twisted.

(11) The multi-core cable for a vehicle according to the above (7),
In a cross section orthogonal to the longitudinal direction of the multi-core cable, a ratio of a major axis dimension to a minor axis dimension (major axis dimension / minor axis dimension) may be 1.8 or more.

  According to the multi-core cable for a vehicle having the above configuration, the cable can be suitably routed in a flat space. Easy to bend in the short axis direction (thickness direction) and easy to route. It is easy to secure a large contact area with a planar mounting target such as a wall, and it is easy to fix a multi-core cable.

<Details of Embodiment of the Present Invention>
Hereinafter, an example of an embodiment of a covered electric wire and a multicore cable for vehicles including the covered electric wire according to the present invention will be described in detail with reference to the drawings.

<First embodiment>
The multi-core cable 1 is used, for example, to connect an ECU (Electric Control Unit) mounted on a vehicle to an electric parking brake, a wheel speed sensor, and the like provided around wheels. The wheels are rotatably supported on the vehicle body around the axle. In some cases, the wheels are supported via a suspension device or a steering device. That is, the wheels are displaceably supported by the vehicle body. The multi-core cable 1 of the present embodiment is suitably used for connecting an ECU fixed to a vehicle body to a component attached to a wheel that is displaceably supported by the vehicle body.
The multi-core cable 1 is required to be routed in a small space in the tire house in which the wheels are housed, and is easy to bend so as not to hinder the displacement of the wheels, and has high durability against repeated bending. Is required.

  FIG. 1 is a sectional view showing a multi-core cable 1 according to the first embodiment of the present invention. FIG. 1 shows a cross section orthogonal to the longitudinal direction of the multi-core cable 1. As shown in FIG. 1, the multi-core cable 1 has two power lines 10, two signal lines 21, two electric wires 31, and a jacket 40. The outer diameter of the multi-core cable 1 of the present embodiment can be 7 mm to 18 mm, preferably 7.5 mm to 13 mm.

(Power line)
Each of the two power lines 10 (an example of a covered electric wire) includes a first conductor 12 (an example of a conductor) and a first insulating layer 13 (an example of an insulating layer) that covers the first conductor 12, respectively. The two power lines 10 are the same in size and material.

  The two power lines 10 can be used to connect the electric parking brake and the ECU. The electric parking brake has a motor that drives a brake caliper. For example, one power line 10 can be used as a power supply line for supplying power to the motor, and the other power line 10 can be used as a ground line for the motor.

The first conductor 12 is configured by twisting a plurality of stranded wires. Each stranded wire is formed by twisting a plurality of strands. The strand is a wire made of copper or a copper alloy. The strand can be made of a material having predetermined conductivity and flexibility, such as tin-plated soft copper wire, in addition to copper and copper alloy. The cross-sectional area of the first conductor 12 can be 1.5 mm ² or more and 3 mm ² or less.

  In the illustrated example, the first conductor 12 is configured by twisting seven stranded wires. In a cross section orthogonal to the longitudinal direction of the power line 10, one stranded wire (hereinafter, referred to as a center stranded wire 14) is located at the center in the radial direction, and six stranded wires (hereinafter, referred to as center stranded wires 14) surround the center stranded wire 14. Hereinafter, referred to as the surrounding stranded wire 15). The center stranded wire 14 is always located at the center in the radial direction, and the peripheral stranded wire 15 is always located around the center stranded wire 14. The positional relationship is maintained over the longitudinal direction of the multi-core cable 1.

  The center stranded wire 14 is configured by twisting 46 strands 16 having a diameter of 0.1 mm. The outer diameter of the center stranded wire 14 is 0.8 mm. The surrounding stranded wire 15 is configured by twisting 72 strands 17 having a diameter of 0.08 mm. The outer diameter of the surrounding stranded wire 15 is 0.8 mm. The strand 16 of the center strand 14 is thicker than the strand 17 of the surrounding strand 15. In FIG. 1, the number of the strands 16 of the center strand 14 is drawn with a number different from the actual number so that it is easy to grasp that the number of strands 16 of the peripheral strand 15 is smaller than the number of strands 17 of the surrounding strand 15. I have.

  It is preferable that the diameter of the strand 16 of the center strand 14 is 0.1 mm or more, and the diameter of the strand 17 of the surrounding strand 15 is 0.08 mm or less. If the diameter of the strand 16 of the center stranded wire 14 is less than 0.1 mm, it is difficult to reduce the cost. If the diameter of the strand 17 of the surrounding stranded wire 15 is larger than 0.08 mm, it is difficult to suppress a decrease in bending resistance. It is preferable that the diameter of the strand 16 of the center strand 14 and the diameter of the strand 17 of the surrounding strand 15 be in the range of 0.05 mm to 0.2 mm.

In the present embodiment, the outer diameter of the peripheral stranded wire 15 is 0.98 times the outer diameter of the center stranded wire 14. That is, the outer diameter of the peripheral stranded wire 15 having the largest outer diameter among the stranded wires is 1.5 times or less the outer diameter of the center stranded wire having the smallest outer diameter among the stranded wires.
The outer diameter of the center stranded wire 14 is 101% of the outer diameter of the peripheral stranded wire 15. That is, the outer diameter of the center stranded wire 14 arranged at the center of the first conductor 12 is 75% or more and 125% or less of the outer diameter of the other peripheral stranded wires 15.
As described above, in this embodiment, since the sizes of the plurality of stranded wires 14 and 15 are uniform, the stranded shape of the first conductor 12 in which the plurality of stranded wires 14 and 15 are stranded is easily stabilized.

  The outer diameter of the first insulating layer 13 can be 2 mm or more and 4 mm or less. The thickness of the thinnest portion of the first insulating layer 13 (the thickness from the surface of the stranded wire to the outer surface of the first insulating layer 13) is 0.3 mm or more and 0.4 mm or less. The first insulating layer 13 is preferably formed of a resin mainly containing a copolymer of ethylene and an α-olefin having a carbonyl group, but is preferably formed of a resin such as a cross-linked heat-resistant polyethylene or a cross-linked fluororesin. Is also good.

  The first insulating layer 13 is preferably formed of a copolymer of ethylene and an α-olefin having a carbonyl group (hereinafter, also referred to as a main component resin) from the viewpoint of improving the bending resistance at low temperatures. The lower limit of the content of the α-olefin having a carbonyl group in the main component resin is preferably 14% by mass, and more preferably 20% by mass. On the other hand, the upper limit of the content of the α-olefin having a carbonyl group is preferably 46% by mass, and more preferably 30% by mass. When the content of the α-olefin having a carbonyl group is smaller than the lower limit, the effect of improving the flex resistance at low temperatures may be insufficient. Conversely, if the content of the α-olefin having a carbonyl group exceeds the upper limit, mechanical properties such as strength of the first insulating layer 13 may be reduced.

  Examples of the α-olefin having a carbonyl group include alkyl (meth) acrylates such as methyl (meth) acrylate and ethyl (meth) acrylate; aryl (meth) acrylates such as phenyl (meth) acrylate; vinyl acetate And vinyl esters such as vinyl propionate; unsaturated acids such as (meth) acrylic acid, crotonic acid, maleic acid, and itaconic acid; vinyl ketones such as methyl vinyl ketone and phenyl vinyl ketone; and (meth) acrylamide. Can be. Among these, alkyl (meth) acrylate and vinyl ester are preferred, and ethyl acrylate and vinyl acetate are more preferred.

  Examples of the main component resin include resins such as EVA, EEA, ethylene-methyl acrylate copolymer (EMA), and ethylene-butyl acrylate copolymer (EBA). Among them, EVA and EEA are preferable.

  In the present embodiment, two power lines 10 are arranged point-symmetrically in a cross section orthogonal to the longitudinal direction of the multi-core cable 1. Since the thick power lines 10 are arranged in a well-balanced manner and have good symmetry, the multi-core cable 1 is unlikely to be twisted. Further, in the cross section orthogonal to the longitudinal direction of the multi-core cable 1, one pair of twisted signal wires 20 and one pair of twisted wires 30 are also arranged point-symmetrically. Has been enhanced.

(Signal line)
Each of the two signal lines 21 includes a second conductor 22 that is thinner than the first conductor 12, and a second insulating layer 23 that covers the second conductor 22. The two signal wires 21 to be twisted have the same size and the same material. The signal lines 21 are twisted in pairs to form a twisted pair signal line 20. The twist pitch of the twisted pair signal line 20 can be 10 times or more and 15 times or less the twisted diameter of the twisted pair signal line 20 (outer diameter of the twisted pair signal line 20). The twisted pair signal line 20 is covered with a signal coating 24. The same material as that of the first insulating layer 13 may be used for the signal coating 24, or a different material may be used.

  The outer diameter of the twisted pair signal line 20 can be substantially the same as the outer diameter of the power line 10. The outer diameter of the power line 10 is preferably 75% or more and 136% or less of the outer diameter of the twisted pair signal line 20. The outer diameter of the power line 10 is more preferably 75% or more and 125% or less of the outer diameter of the twisted pair signal line 20. The outer diameter of the power line 10 is more preferably 90% or more and 115% or less of the outer diameter of the twisted pair signal line 20.

  The signal line 21 can be used to transmit a signal from a sensor, or can be used to transmit a control signal from an ECU. The two signal lines 21 can be used, for example, for wiring of an anti-lock brake system (ABS). Each of the two signal lines 21 can be used, for example, as a line connecting a differential wheel speed sensor and the ECU of the vehicle.

The second conductor 22 may be configured by twisting a plurality of strands as illustrated, or may be configured by a single strand. The second conductor 22 may be made of the same material as that of the strand forming the first conductor 12, or may be made of a different material. The cross-sectional area of the second conductor 22 can be not less than 0.13 mm ^{2 and not} more than 0.5 mm ² .
The same material as the first insulating layer 13 may be used for the second insulating layer 23, or a different material may be used. The outer diameter of the second insulating layer 23 can be not less than 1.0 mm and not more than 2.2 mm.

(Electrical wire)
Each of the two electric wires 31 includes a third conductor 32 that is thinner than the first conductor 12, and a third insulating layer 133 that covers the third conductor 32. The two electric wires 31 are twisted in a pair to constitute a twisted pair electric wire 30. The two electric wires 31 to be twisted have the same size and the same material. The electric wire 31 may be the same in size and material as the signal line 21. The twisted pair wire 30 is preferably twisted in the same direction as the twisted pair signal wire 20. It is preferable that the twisted wire 30 has the same twist pitch as the twisted signal wire 20. The twisted pair wire 30 is covered with a wire covering 34. The same material as that of the first insulating layer 13 may be used for the electric wire covering 34, or a different material may be used.

  The outer diameter of the twisted pair wire 30 can be substantially the same as the outer diameter of the twisted pair signal wire 20. The outer diameter of the twisted pair wire 30 can be substantially the same as the outer diameter of the power line 10. The outer diameter of the power line 10 is preferably 75% or more and 136% or less of the outer diameter of the twisted pair wire 30. The outer diameter of the power line 10 is more preferably 75% or more and 125% or less of the outer diameter of the twisted pair wire 30. The outer diameter of the power line 10 is more preferably 90% or more and 115% or less of the outer diameter of the twisted pair electric wire 30.

  The electric wire 31 can be used to transmit a signal from a sensor, can be used to transmit a control signal from an ECU, and can also be used as a power supply line for supplying power to an electronic device. . The electric wire 31 can be used, for example, as a power supply line, a control line, or a sensor wire used in an active suspension system that changes the hydraulic characteristics of the suspension. Alternatively, the electric wire 31 can be used, for example, for wiring a CAN (Controller Area Network) for a vehicle.

The third conductor 32 may be configured by twisting a plurality of strands as illustrated, or may be configured by a single strand. The third conductor 32 may be made of the same material as the conductors forming the first conductor 12 and the second conductor 22, or may be made of a different material. The cross-sectional area of the third conductor 32 can be not less than 0.13 mm ^{2 and not} more than 0.5 mm ² .
The third insulating layer 133 can use the same material as the second insulating layer 23, or may use a different material. The outer diameter of the third insulating layer 133 can be not less than 1.0 mm and not more than 2.2 mm.

(Jacket)
The jacket 40 covers all the lines including the two power lines 10, the two signal lines 21, and the two electric wires 31. Two power lines 10, one twisted pair signal line 20, and one twisted pair wire 30 are integrally twisted. The outer cover 40 covers the two power lines 10, the one twisted pair signal line 20, and the one twisted pair wire 30, which are twisted together.

  The outer cover 40 has an inner outer cover 41 and an outer outer cover 42 located outside the inner outer cover 41. The outer diameter of the jacket 40 can be not less than 7.5 mm and not more than 11 mm.

  The inner jacket 41 maintains the twisted shape of all the wires including the two power lines 10, the two signal lines 21, and the two electric wires 31. The inner jacket 41 is formed by extruding the outer circumferences of the two power lines 10, the two signal lines 21, and the two electric wires 31. The inner jacket 41 may be made of the same material as the outer jacket 42, or may be made of a different resin from the outer jacket 42. The inner jacket 41 is formed of, for example, a polyolefin-based resin such as polyethylene or ethylene-vinyl acetate copolymer (EVA), a polyurethane elastomer, a polyester elastomer, or a resin composition formed by mixing at least two of these. be able to. The inner jacket 41 may be cross-linked.

  The outer jacket 42 is provided to protect all the lines including the two power lines 10, the two signal lines 21, and the two electric wires 31 from the outside. The outer jacket 42 is formed by extrusion-coating the outer periphery of the inner jacket 41. The outer jacket 42 may be comprised of a cross-linked / non-cross-linked polyurethane (TPU) with good wear resistance. Outer jacket 42 is preferably made of crosslinked polyurethane because of its excellent heat resistance. For example, the outer jacket 42 can be made of polyurethane having excellent wear resistance, and the inner jacket 41 can be made of polyethylene, which is less expensive than the polyurethane constituting the outer jacket 42, as long as the effect is exhibited.

(Intervening)
The multi-core cable 1 has an interposition 50. The interposition 50 is provided inside the jacket 40. The interposition 50 is provided between the two power lines 10. The interposition 50 can be arranged between the two power lines 10 by twisting the two power lines 10, the twisted pair signal lines 20, and the twisted electric wires 30 together with the interpositions 50.

  The interposition 50 can be made of a fiber such as a staple yarn or a nylon yarn. It is preferable that the interposition 50 is made of a fiber having a good slippage with respect to the power line 10. Since the staple yarn and the nylon yarn have a buffering action against the displacement of the power line 10, it is preferable that the interposition 50 is formed of the staple yarn or the nylon yarn. The interposition 50 may be a yarn composed of a tensile fiber. The interposition 50 may be a yarn made of the same material as the jacket 40 or a yarn made of a material different from that of the jacket 40. The interposition 50 may be a yarn made of, for example, polyethylene (PE) or polypropylene (PP).

(Suppression winding)
The multi-core cable 1 may have a hold-down winding 51. The hold-down winding 51 covers the two power lines 10, the one twisted signal line 20, and the one twisted electric wire 30. The hold-down winding 51 stably maintains the twisted shape of these wires. The hold-down winding 51 is provided inside the jacket 40.

  For example, a paper tape, a nonwoven fabric, or a resin tape such as polyester can be used as the hold-down winding 51. Further, the hold-down winding 51 may be spirally wound around the two power lines 10, the one twisted pair signal line 20, and the one twisted pair electric wire 30, or may be vertically attached. The winding direction may be Z winding or S winding. The winding direction may be the same as the twist direction of the twisted signal wire 20 or the twisted wire 30 or may be wound in the opposite direction. When the winding direction of the control winding 51 is opposite to the twisting direction of the twisted signal wire 20 and the twisted wire 30, irregularities are less likely to be formed on the surface of the winding 51, and the outer diameter shape of the multi-core cable 1 is easily stabilized. It is preferred.

  When the resin jacket 40 is provided by extrusion coating, the resin may adhere to the two power lines 10 and it may be difficult to separate the two power lines 10 at the terminal of the multi-core cable 1. Therefore, by providing the suppression winding 51, the resin can be prevented from adhering to the two power lines 10, and the two power lines 10 can be easily taken out at the terminal.

(Shield layer)
The multi-core cable 1 may have a shield layer for suppressing noise radiated to the outside. The shield layer can be formed by winding a metal tape around the power line 10, the twisted signal line 20, and the twisted electric wire 30. The shield layer can also be formed by spirally winding a number of fine metal wires around these wires. Alternatively, the shield layer can be configured by braiding with a thin metal wire. The shield layer can be provided outside the holding roll 51 and inside the jacket 40.

(effect)
When configuring a stranded wire having a desired cross-sectional area, if the stranded wire is configured with a thick strand, the number of stranded wires is reduced as compared with the case where a stranded wire is configured with a thin strand, so that the cost can be reduced. . However, when the conductor is formed of a thick wire, the bending resistance of the conductor is reduced as compared with the case where the conductor is formed of a thin wire.

  Therefore, according to the power line 10 according to the embodiment, only the strand 16 of the center stranded wire 14 uses a strand thicker than the other strands 17. As a result, the cost of the conductor can be reduced as compared with the case where the conductor is composed of only thin wires.

The use of the thick strand 16 as a part of the strand forming the first conductor 12 may cause a decrease in the bending resistance of the entire first conductor 12. However, since the center stranded wire 14 composed of the thick strand 16 is arranged at the center of the first conductor 12, a decrease in the bending resistance of the entire first conductor 12 is suppressed.
For example, when the power line 10 is bent, an axial compressive stress acts on an inner portion of the bent portion and an axial tensile stress acts on an outer portion of the bent portion, but a central portion of the bent portion acts on the central portion of the bent portion. Large stress is unlikely to act. When the power line 10 is bent, the surrounding stranded wire 15 is located at an inner portion and an outer portion of the bent portion, and the center stranded wire 14 is located at the center portion of the bent portion. In other words, the peripheral stranded wire 15 has a large effect on the bending resistance of the power line 10, but the center stranded wire 14 is less likely to have a large effect on the bending resistance than the peripheral stranded wire 15. Therefore, in the power line 10 according to the present embodiment, by arranging the center stranded wire 14 composed of the thick strand 16 at the center of the first conductor 12, the cost is reduced while suppressing the decrease in bending resistance. Have been.

  In the multi-core cable 1 of the present embodiment, the first conductor 12 is configured by twisting one central stranded wire 14 and six peripheral stranded wires 15 arranged around the central stranded wire 14. I have. In the cross section of the power line 10, the stranded wires 14, 15 can be arranged in a well-balanced manner, and the stranded structure of the first conductor 12 can be stably maintained.

  In the multicore cable 1 of the present embodiment, the outer diameter of the power line 10 is preferably 75% or more and 136% or less of the outer diameter of the twisted pair signal line 20. The outer diameter of the power line 10 is more preferably 75% or more and 125% or less of the outer diameter of the twisted pair signal line 20. The outer diameter of the power line 10 is more preferably 90% or more and 115% or less of the outer diameter of the twisted pair signal line 20. The outer diameter of the power line 10 is the outer diameter of the first insulating layer 13. The outer diameter of the twisted pair signal line 20 is the diameter of a virtual circumscribed circle where the pair of signal lines 21 circumscribe. For example, the outer diameter of the twisted pair signal line 20 can be measured by sandwiching the two twisted signal lines 21 with a micrometer.

According to the multi-core cable 1 according to the present embodiment, since the sizes of the two power lines 10 and the twisted pair signal lines 20 are substantially the same, the twisted shape is easily maintained, and the diameter of the multi-core cable 1 is increased. Are easy to align along the longitudinal direction.
Further, in the cross section orthogonal to the longitudinal direction of the multi-core cable 1, the two power lines 10 and the twisted pair signal lines 20 are arranged while maintaining a fixed positional relationship, so that the cross-sectional shape after twisting is circular. Get closer. For this reason, it is easy to make the cross-sectional shape of the outer cover 40 close to a perfect circle, a gap is hardly generated between the outer cover 40 and the water blocking member, and the water stopping performance is further increased.
Further, it is more preferable that the sizes of the twisted pair signal wire 20 and the twisted pair wire 30 substantially match.

  In a multi-core cable provided with a plurality of wires, the wires may rub against each other, and the bending resistance may be reduced. However, according to the multi-core cable 1 according to the present embodiment, when the multi-core cable 1 is bent, the wires 10, 20, and 30 slide on the interposition 50. The force generated due to the contact with the twisted signal line 20 and the contact between the power line 10 and the twisted pair wire 30 is small. For this reason, the bending resistance of the multi-core cable 1 is enhanced.

<Second embodiment>
In the above-described first embodiment, the multi-core cable 1 in which the two power lines 10, the two signal lines 21, and the two electric wires 31 are twisted has been described, but the present invention is not limited to this. FIG. 2 is a sectional view of a multi-core cable 101 for a vehicle according to a second embodiment of the present invention.

  The multi-core cable 101 according to the present embodiment includes a single twisted pair signal wire 20 including two power lines 10 and two signal lines 21 and a single twisted pair wire 30 including two electric wires 31. And one second twisted pair wire 60 composed of two electric wires 61 and one third twisted pair electric wire 70 composed of two electric wires 71. These two power lines 10, one twisted pair signal line 20, one twisted pair wire 30, one second twisted pair wire 60, one third twisted pair wire 70, Are lined up in a row and covered with a jacket 40. In this cross section, the ratio (L2 / L1) of the dimension L2 in the long axis direction to the dimension L1 in the short axis direction is 1.8 or less. In the example shown, the ratio L2 / L1 is 4.6. The ratio L2 / L1 can be 7 or less.

  The second twisted pair electric wire 60 is configured by twisting two electric wires 61 in a pair. Each of these two electric wires 61 includes a fourth conductor 62 thinner than the first conductor 12 and a fourth insulating layer 63 covering the fourth conductor 62. These two electric wires 61 have the same size and material.

  The third twisted pair electric wire 70 is configured by twisting two electric wires 71 in pairs. Each of these two electric wires 71 includes a fifth conductor 72 that is thinner than the first conductor 12 and a fifth insulating layer 73 that covers the fifth conductor 72. These two electric wires 71 have the same size and material.

  The power line 10 can be used, for example, to connect the motor of the electric parking brake and the ECU. The twisted pair signal line 20 can be used, for example, for ABS wiring. The twisted pair wire 30 can be used for wiring of a damper control system, for example. The second twisted pair wire 60 and the third twisted pair wire 70 can be used, for example, for wiring in a vehicle-mounted network.

  Also in the present embodiment, the power line 10 is configured by twisting one center stranded wire 14 and six peripheral stranded wires 15 arranged around the center stranded wire 14. The strand 16 of the center strand 14 is thinner than the strand 17 of the surrounding strand 15. For this reason, the cost is reduced while suppressing the decrease in the bending resistance.

  In the first embodiment and the second embodiment described above, the example in which the first conductor is constituted by one center stranded wire and six peripheral stranded wires has been described, but the present invention is not limited to this. The number of strands constituting the center strand and the number of strands constituting the surrounding strand are not limited.

  The twist configuration of the first conductor is not particularly limited. However, when the first conductor is composed of one center stranded wire and six peripheral stranded wires described in the first embodiment and the second embodiment described above, the twist is This is preferable because the structure is easily maintained stably.

  Further, in the above-described embodiment, the example in which the covered electric wire of the present invention is applied to the power lines 10 and 10A has been described, but may be applied to the signal line 21, the electric wires 31, 61, 71, and the like. The covered electric wire of the present invention may be applied to all electric wires constituting the multi-core cable, or the coated electric wire of the present invention may be applied to a part of the electric wires constituting the multi-core cable.

<Example>
Next, as shown in Table 1 below, power lines according to Example 1, Example 2, and Comparative Example 1 were produced, and their bending resistance was evaluated. Each power line was configured by twisting one central stranded wire located at the center and six peripheral stranded wires provided around the central stranded wire.

(Example 1)
Forty-six strands of a tin-copper alloy having a diameter of 0.10 mm were twisted to produce a center stranded wire having a diameter of 0.8 mm. Twenty-two copper alloy wires having a diameter of 0.08 mm were twisted to prepare a peripheral stranded wire having a diameter of 0.8 mm. Six peripheral strands were twisted around one central strand to produce a first conductor. This first conductor was coated with an ethylene-ethyl acrylate copolymer (EEA) as a first insulating layer having a thickness of 0.3 mm to produce a power line of Example 1.

(Example 2)
Forty-six strands of a tin-copper alloy having a diameter of 0.10 mm were twisted to produce a center stranded wire having a diameter of 0.8 mm. Twenty-two copper alloy wires having a diameter of 0.08 mm were twisted to prepare a peripheral stranded wire having a diameter of 0.8 mm. Six peripheral strands were twisted around one central strand to produce a first conductor. This first conductor was coated with a crosslinked flame-retardant polyethylene as a first insulating layer with a thickness of 0.3 mm to produce a power line of Example 2.

(Comparative Example 1)
Twenty-two strands made of a tin-copper alloy having a diameter of 0.08 mm were twisted to prepare a center stranded wire and a peripheral stranded wire having a diameter of 0.8 mm. Six peripheral strands were twisted around one central strand to produce a first conductor. This first conductor was covered with EEA as a first insulating layer with a thickness of 0.3 mm, and a power line of Comparative Example 1 was produced.

(Repeated bending test)
The bending resistance of the power line was evaluated according to the repeated bending test specified in ISO 14572: 2011 (E) 5.9. In the repetitive bending test, the power line was repeatedly bent so as to be from -90 ° to + 90 °. If the amount of decrease in resistance from the initial resistance of the power line after bending 100,000 times was 5% or more, it was determined that the power line was broken. A case where the amount of decrease in the resistance value of the power line from the initial resistance value was less than 5% was determined to be acceptable. Furthermore, the case where the amount of decrease in the resistance value from the initial resistance value after bending 150,000 times was less than 5% was defined as excellent.
The power lines of Examples 1 and 2 passed. In particular, the power line of Example 1 was excellent. However, the power line of Comparative Example 1 was rejected.

(U-shaped bending test)
The automotive standard JASO C467-97, determined by the Japan Society of Automotive Engineers, 7.16, was evaluated according to the sensor harness bending test. In this test, the power line was repeatedly bent from a straight line to a U-shape. After bending 300,000 times at −30 °, it was subsequently bent 700,000 times at room temperature. After the test, a case where there was no abnormality in appearance such as cracks or cracks and the amount of decrease in resistance value from the initial resistance value was less than 5% was regarded as pass. Furthermore, after bending 300,000 times at −30 °, and subsequently bending 1200,000 times at room temperature, there is no abnormality in appearance such as cracks and cracks, and the resistance value from the initial resistance value is not changed. The case where the reduction amount was less than 5% was defined as excellent.
The power lines of Examples 1 and 2 passed. In particular, the power line of Example 1 was excellent. However, the power line of Comparative Example 1 was rejected.

1,101 Multi-core cable 10,10A Power line 12,12A First conductor 13 First insulating layer 14 Center stranded wire 15 Surround stranded wire 16,17 Element wire 18 Intermediate stranded wire 20 Twisted signal wire 21 Signal wire 22 Second conductor 23 Second insulating layer 30 Twisted electric wire 31 Electric wire 32 Third conductor 33 Third insulating layer 40 Outer cover 41 Inner cover 42 Outer cover 50 Interposition 51 Squeeze winding 60 Second twisted pair wire 61 Electric wire 62 Fourth conductor 63 Fourth insulation layer 70 Third twisted pair wire 71 Wire 72 Fifth conductor 73 Fifth insulation layer

Claims (12)

A covered wire in which a conductor is covered with a resin insulating layer,
The conductor is configured by twisting a plurality of stranded wires,
The stranded wire is configured by twisting a plurality of strands,
A covered electric wire, wherein a diameter of the strand constituting the stranded wire disposed at the center of the conductor is larger than a diameter of the strand constituting the other stranded wire. Sectional area of the conductor is 1.5 mm ² or more 3.0 mm ² or less, coated wire according to claim 1. The conductor is configured by twisting the seven strands,
3. The coated electric wire according to claim 1, wherein six of the stranded wires are twisted around one of the stranded wires arranged at the center of the conductor. 4.   The diameter of the strand constituting one of the strands arranged at the center of the conductor is 0.1 mm or more, and the diameter of the strand constituting the other strand is 0.08 mm or less. The insulated wire according to claim 3, which is provided.   The coated electric wire according to any one of claims 1 to 4, wherein the insulating layer mainly includes a copolymer of ethylene and an α-olefin having a carbonyl group.   The covered electric wire according to any one of claims 1 to 5, wherein the outer diameter of the stranded wire having the largest outer diameter is 1.5 times or less the outer diameter of the stranded wire having the smallest outer diameter. .   The outer diameter of the stranded wire arranged at the center of the conductor is 75% or more and 125% or less of the outer diameter of the other stranded wires according to any one of claims 1 to 6. Insulated wires. The two covered electric wires according to any one of claims 1 to 7, and
A multi-core cable for a vehicle, comprising: a jacket covering the two covered electric wires. A second conductor thinner than the conductor, a second insulating layer covering the second conductor, having a plurality of second wires each having a,
The multi-core cable for a vehicle according to claim 8, wherein the second electric wires are twisted in pairs to form a pair-twisted second electric wire. The two covered electric wires and the twisted pair second electric wire are stranded,
The multi-core cable for a vehicle according to claim 9, wherein the jacket covers the two twisted covered electric wires and the paired second electric wires.   The multi-core cable for a vehicle according to claim 10, wherein the two covered electric wires are arranged point-symmetrically in a cross section orthogonal to the longitudinal direction of the multi-core cable.   9. The vehicle according to claim 8, wherein a ratio of a major axis dimension to a minor axis dimension (major axis dimension / minor axis dimension) is 1.8 or more in a cross section orthogonal to the longitudinal direction of the multi-core cable. Core cable.

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