JP2017010903A - Bending resistant wire and wire harness - Google Patents

Abstract

An object of the present invention is to provide a bending-resistant electric wire and a wire harness that can improve bending resistance without requiring a dedicated member. A bending-resistant electric wire (1) includes a conductor portion (10) formed by twisting a plurality of conductive strands (11) and an insulating covering portion (20) covering the outer periphery of the conductor portion (10). The part 20 has a tensile strength of 10 MPa or more and 13 MPa or less, and the conductor part 10 has a strand pitch of the wire 11 of 10 mm or more and 21 mm or less. [Selection] Figure 2

Description

  The present invention relates to a bending-resistant electric wire and a wire harness.

  In recent years, automobiles have become more multi-component and have higher performance, and the need for flex-resistant electric wires is increasing. As a means for improving the flexibility of an electric wire, a cable in which a thin inclusion is interposed between adjacent stranded wires has been proposed. According to this cable, since the friction between the stranded wires is reduced by the small-diameter inclusions, the breakage of the strands constituting the stranded wires is suppressed, and the flexibility can be improved (see, for example, Patent Document 1). ). In addition, an insulating wire in which a slurry layer is provided between a conductor and an insulator has also been proposed. According to this insulating wire, the friction between the conductor and the insulator is reduced by the slurry layer, so that the breakage of the strands constituting the stranded wire is suppressed, and the flexibility can be improved (see, for example, Patent Document 2). ).

JP 2011-18545 A JP 2010-177189 A

  However, since the electric wires described in Patent Documents 1 and 2 need to be provided with a small-diameter inclusion or a slurry layer, a dedicated member for improving the bending resistance is required.

  The present invention has been made to solve such a conventional problem, and an object of the present invention is to provide a bending-resistant electric wire and a wiring harness that can improve bending resistance without requiring a dedicated member. Is to provide.

  The bending-resistant electric wire of the present invention includes a conductor portion formed by twisting a plurality of conductive strands, and an insulating covering portion that covers an outer periphery of the conductor portion, and the covering portion is a tensile member. The strength is 10 MPa or more and 13 MPa or less, and the conductor portion is characterized in that the strand pitch of the strand is 10 mm or more and 21 mm or less.

  According to the bending-resistant electric wire of the present invention, since the covering portion has a tensile strength of 13 MPa or less, the covering portion is easily deformed when bent. As a result, a gap is generated between the strands during bending, and wear between the strands is reduced, and the possibility of breakage of the strands is reduced. Furthermore, since the strand pitch of the conductor is 21 mm or less in the conductor portion, it is possible to prevent the strand from being twisted due to the pitch being too wide and to break the strand due to local stress applied during bending. can do. Thus, since the possibility of the breakage of the strands during bending can be reduced, the bending resistance can be improved without requiring a dedicated member.

  Furthermore, since the covering portion has a tensile strength of 10 MPa or more, it is difficult for buckling to occur in the electric wire itself, and it is possible to prevent the electric wire from being easily bent when the connector is inserted after attaching a terminal to the electric wire. In addition, since the conductor portion has a strand twist pitch of 10 mm or more, there is no situation in which the pitch is too narrow to make manufacture difficult.

  Furthermore, the wire harness of this invention is characterized by including the bending-resistant electric wire as described above.

  According to the wire harness of the present invention, since it is a wire harness including a bending-resistant electric wire, it is possible to provide a wire harness that is excellent in bending resistance and that is suitable as a wire harness that is repeatedly bent such as a sliding door. . Furthermore, since it is difficult for buckling to occur in a bending-resistant electric wire, it is possible to provide a wire harness that suppresses a decrease in productivity.

  ADVANTAGE OF THE INVENTION According to this invention, the bending resistant electric wire and wire harness which can improve bending resistance without requiring a member for exclusive use can be provided.

It is a perspective view showing an example of a wire harness concerning an embodiment of the present invention. It is sectional drawing which shows the bending-proof electric wire shown in FIG. 1, and has shown the time of non-bending. It is sectional drawing which shows the bending resistant electric wire shown in FIG. 1, and has shown at the time of bending. It is sectional drawing which shows the electric wire which concerns on a reference example, and has shown the time of bending. It is a graph which shows the characteristic of the bending resistant electric wire which concerns on an Example and a comparative example.

  Preferred embodiments of the present invention will be described below with reference to the drawings. However, the present invention is not limited to the following embodiments.

  FIG. 1 is a perspective view showing an example of a wire harness according to an embodiment of the present invention. As shown in FIG. 1, the wire harness WH is a bundle of a plurality of electric wires W, and at least one of the plurality of electric wires W is constituted by a bending-resistant electric wire 1 described in detail below. For example, as shown in FIG. 1, such a wire harness WH may be provided with connectors C at both ends of the electric wire W, or may be wound with a tape (not shown) to collect a plurality of electric wires W. Good. Moreover, the wire harness WH may be provided with exterior components (not shown), such as a corrugated tube.

  2 is a cross-sectional view showing the bending-resistant electric wire shown in FIG. As shown in FIG. 2, the bending-resistant electric wire 1 includes a conductor portion 10 formed by twisting a plurality of conductive strands 11 and an insulating covering portion 20 that covers the outer periphery of the conductor portion 10. It is configured.

  The strand 11 which comprises the conductor part 10 is comprised, for example with pure copper, and specifically contains 99.9 mass% or more of Cu, and others are comprised with the impurity (an additive is included).

  The covering portion 20 is composed of, for example, a polyethylene resin mixture, and is specifically composed of polyethylene, a flame retardant mixture, and additives (antioxidants and stabilizers), and 60% by mass or more of polyethylene with respect to 100% by mass of these. 80% by mass or less, 5% by mass to 20% by mass of a flame retardant mixture, and 10% by mass to 25% by mass of additives.

  3 is a cross-sectional view showing the bending-resistant electric wire shown in FIG. 1, and FIG. 4 is a cross-sectional view showing an electric wire according to a reference example. 3 and 4 show cross sections of the respective electric wires when bent.

  In the bending-resistant electric wire 1 according to this embodiment, the tensile strength of the covering portion 20 is 13 MPa or less. For this reason, the bending-resistant electric wire 1 according to the present embodiment is easily deformed so that the covering portion 20 is deformed when bent, and the electric wire 1 is deformed so that the cross section of the electric wire 1 is crushed as shown in FIG. Thereby, the strand 11 becomes easy to move. That is, a gap is generated between the strands 11 at the time of bending, so that the wear between the strands 11 is reduced and the possibility of disconnection of the strands 11 is reduced.

  On the other hand, in the electric wire according to the reference example, the tensile strength of the covering portion 120 is not 13 MPa or less (specifically, 20 MPa or more and 23 MPa or less). For this reason, the coating | coated part 120 cannot change easily at the time of bending, and the cross-sectional shape of an electric wire does not change so much as shown in FIG. Therefore, the strands 111 may be worn at the time of bending, and the strands 111 may be disconnected.

  In addition, the bending resistant electric wire 1 according to the present embodiment has a twist pitch of the strands 11 of the conductor portion 10 of 21 mm or less. For this reason, the bending-resistant electric wire 1 according to the present embodiment prevents the strand 11 from being broken due to the pitch being too wide, causing the strand 11 to be twisted, and applying local stress during bending. be able to.

  Thus, since the bending resistant electric wire 1 which concerns on this embodiment can reduce the possibility of the disconnection of the strand 11 at the time of bending, it can improve bending resistance without requiring a dedicated member.

  Here, in the bending-resistant electric wire 1 according to the present embodiment, it is preferable that the tensile strength of the covering portion 20 is 10 MPa or more. This is because it is difficult for buckling of the bending-resistant electric wire 1 itself to occur, and it is possible to prevent the electric wire 1 from being easily bent when the connector is inserted after attaching a terminal to the electric wire 1.

  In addition, the conductor portion 10 preferably has a strand pitch of the strands 11 of 10 mm or more. This is because the situation in which the pitch is too narrow and the manufacture becomes difficult does not occur.

  Next, the bending resistant electric wire 1 which concerns on an Example and a comparative example is demonstrated. FIG. 5 is a chart showing the characteristics of the bent wire according to the example and the comparative example.

  First, in the bending-resistant electric wires according to Example 1 and Example 2, 37 wires made of pure copper (containing 99.9% by mass or more of Cu and other impurities (including additives)) having a diameter of 0.26 mm are used. The conductor part was comprised by preparing this and twisting this. Here, in Example 1, the twist pitch was 10 mm, and in Example 2, the twist pitch was 21 mm. And non-crosslinked polyethylene (including 50 to 80% by mass of polyethylene, 5 to 25% by mass of flame retardant mixture, 10 to 25% by mass of additives, 100% by mass in total) Was used as an insulator material, and this was coated on the conductor portion as described above. The thickness (insulator thickness) of the covering portion at the time of covering was 0.42 mm in both Example 1 and Example 2, and the finished outer diameter of the bending-resistant electric wire was 2.6 mm. In addition, the tensile strength of the coating part at this time was 10 MPa or more and 13 MPa or less in both Example 1 and Example 2.

  Further, in the bending-resistant electric wire according to Example 3, 19 strands made of pure copper (having the same composition as in Examples 1 and 2) having a diameter of 0.16 mm were prepared, and the conductor portion was formed by twisting them. Configured. Here, the twist pitch was 16 mm. And crosslinked polyethylene (polyethylene is contained in an amount of 50% by mass or more and 80% by mass or less, a flame retardant mixture is contained in an amount of 5% by mass or more and 25% by mass or less, and an additive is contained in an amount of 10% by mass or more and 25% by mass or less. An insulator material was coated on the conductor portion as described above. The thickness of the covering portion (insulator thickness) at the time of covering was 0.3 mm, and the finished outer diameter of the bent wire was 1.4 mm. In addition, the tensile strength of the coating part at this time was 10 MPa or more and 13 MPa or less.

  In the electric wires according to Comparative Example 1 and Comparative Example 2, 37 conductors made of pure copper (having the same composition as in Examples 1 and 2) having a diameter of 0.26 mm were prepared and twisted to provide a conductor. The part was configured. Here, in Comparative Example 1, the twist pitch was 31 mm, and in Comparative Example 2, the twist pitch was 39 mm. In addition, in the electric wire which concerns on the comparative example 1 and the comparative example 2, the structure of the coating | coated part was the same as Example 1 and Example 2, and the tensile strength of the coating | coated part was 10 MPa or more and 13 MPa or less.

  Furthermore, in the electric wires according to Comparative Example 3 and Comparative Example 4, the conductor part was the same as Example 2 and Comparative Example 2, respectively, but the covered part was insulated with crosslinked polyethylene (having the same composition as Example 3). A body material was coated on the conductor portion as described above. The thickness (insulator thickness) of the coating portion at the time of coating was 0.42 mm in both Comparative Example 3 and Comparative Example 4, and the finished outer diameter of the electric wire was 2.6 mm. In addition, the tensile strength of the coating part at this time was 14 MPa or more and 16 MPa or less.

  In addition, in the electric wires according to Comparative Example 5 and Comparative Example 6, 37 strands made of pure copper (having the same composition as in Examples 1 and 2) having a diameter of 0.26 mm were prepared and twisted. A conductor part was constructed. Here, in Comparative Example 5, the twist pitch was 21 mm, and in Comparative Example 6, the twist pitch was 30 mm. Polypropylene (polypropylene 40% by mass to 70% by mass, ethylene / olefin copolymer 35% by mass to 45% by mass, inorganic filler mixture 1% by mass to 10% by mass, additive 1% by mass % And 10 mass% or less, and 100 mass% in total) was used as the insulator material, and this was coated on the conductor portion as described above. The thickness (insulator thickness) of the coating portion at the time of coating was 0.42 mm in both Comparative Example 5 and Comparative Example 6, and the finished outer diameter of the electric wire was 2.6 mm. In addition, the tensile strength of the coating part at this time was 20 MPa or more and 23 MPa or less.

  Moreover, in the electric wire which concerns on the comparative example 7, the conductor part was made the same as Example 3. FIG. Further, non-crosslinked polyethylene (having the same composition as in Examples 1 and 2) was used as an insulator material, and this was coated on the above-described conductor portion. The thickness of the covering portion (insulator thickness) at the time of covering was 0.3 mm, and the finished outer diameter of the bent wire was 1.4 mm. In addition, the tensile strength of the coating part at this time was 8 MPa or more and less than 10 MPa.

  And the bending test and the buckling test were done about said Examples 1-3 and Comparative Examples 1-7. For the bending test, using a cylindrical mandrel bending tester, the wires according to the respective examples and comparative examples were bent straight from a state where the bending radius was 20 mm in an angle range of −90 ° to 90 ° at room temperature. Was repeated and the number of times of bending (number of reciprocations) when the wire was broken was measured. The bending test was performed with no load (0 g load), and the bending speed was 1 time / s.

  For the buckling test, the electric wires according to each of the examples and comparative examples were straightened and fixed at both ends with a predetermined instrument, and then the predetermined instruments were brought closer to each other and the load when the electric wire was bent was measured. did. The predetermined instrument fixed (pinch) both ends of the electric wire to 15 mm, and the distance between the predetermined instruments was set to 10 mm (that is, the length of the portion to which the load was applied was set to 10 mm). At this time, the case where the load was 15N or more was “◯”, and the case where the load was less than 15N was “×”.

  In addition, when it is less than 15N, when inserting a terminal in the terminal accommodating chamber of a connector after attaching a terminal to an electric wire, an electric wire will buckle and the productivity of a wire harness will fall. On the other hand, if it is 15 N or more, a decrease in productivity can be prevented.

  First, the number of bendings was 72,000 in Example 1, 60000 in Example 2, 90000 in Example 3, and 60000 or more in each case. In Examples 1 to 3, the buckling load was 15 N or more.

  On the other hand, the number of bendings is 47,000 in Comparative Example 1, 40000 in Comparative Example 2, 50000 in Comparative Example 3, 45000 in Comparative Example 4, and 40000 in Comparative Example 5. It was 32000 times in Comparative Example 6. That is, in Comparative Examples 1-6, the load at the time of buckling was all good at 15 N or more, but the number of bendings was less than 60000 times.

  From the above, it was found that when the tensile strength of the covering portion exceeds 13 MPa, or when the twist pitch exceeds 21 mm, the number of bendings is less than 60000 times.

  Furthermore, in Comparative Example 7, the number of flexing was 95,000 times, which was a preferable result, but the load during buckling was less than 15N.

  Therefore, it was found that when the tensile strength of the covering portion was less than 10 MPa, the load during buckling would be less than 15N.

  Thus, according to the bending-resistant electric wire 1 according to the present embodiment, since the covering portion 20 has a tensile strength of 13 MPa or less, the covering portion 20 is easily deformed when bent. As a result, a gap is generated between the strands 11 when bent, wear of the strands 11 is reduced, and the possibility of disconnection of the strands 11 is reduced. Furthermore, since the twisted pitch of the strands 11 of the conductor portion 10 is 21 mm or less, the pitch is too wide, the strands 11 are crushed, local stress is applied during bending, and the strands 11 are disconnected. Can also be prevented. In this way, since the possibility of disconnection of the element wire 11 at the time of bending can be reduced, the bending resistance can be improved without requiring a dedicated member.

  Furthermore, since the covering portion 20 has a tensile strength of 10 MPa or more, the electric wire 1 is less likely to buckle and prevents the electric wire 1 from being easily bent when a connector is inserted after attaching a terminal to the electric wire 1. be able to. Moreover, since the twist pitch of the strand 11 of the conductor part 10 is 10 mm or more, the situation where manufacture becomes difficult because the pitch is too narrow does not arise.

  Moreover, according to the wire harness WH which concerns on this embodiment, since it is the wire harness WH containing the bending-resistant electric wire 1, it is excellent in bending resistance, for example, is suitable as a wire harness WH used for the site | part bent repeatedly, such as a slide door. Can be provided.

  As mentioned above, although this invention was demonstrated based on embodiment, this invention is not limited to the said embodiment, You may add a change in the range which does not deviate from the meaning of this invention, and combines each embodiment. Also good.

  For example, the bending-resistant electric wire 1 according to this embodiment is a single electric wire, but may be applied to a twisted wire or the like as long as the bending-resistant electric wire 1 is included.

1: Bending resistant electric wire 10: Conductor portion 11: Wire 20: Covering portion C: Connector W: Electric wire WH: Wire harness

Claims (2)

A conductor formed by twisting a plurality of conductive strands;
An insulating covering portion covering the outer periphery of the conductor portion,
The covering portion has a tensile strength of 10 MPa or more and 13 MPa or less,
The conductor part has a twist pitch of a strand of 10 mm or more and 21 mm or less. A wire harness comprising the bending-resistant electric wire according to claim 1.

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