JP2008159403A - Wire conductor, and insulated wire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lightweight wire conductor capable of improving strength degradation caused by diameter reduction, and of suppressing heat generation in carrying a current even if severance occurs in wires by any chance. <P>SOLUTION: This wire conductor 10a is formed by intertwining seven copper element wires 12 with one stainless steel element wire 14. The stainless steel element wire 12 is small in a coefficient of elongation smaller than that of the copper element wire 12, and formed to increase a cross-sectional area. The wire conductor 10a may be circularly compressed. It is preferable that the cross-sectional area of the wire conductor 10a is ≤0.3 mm<SP>2</SP>. This insulated wire is composed by covering the outer periphery of the wire conductor 10a with an insulating material. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a wire conductor and an insulated wire, and more particularly to a wire conductor and an insulated wire that are suitably used for an automotive wire.

  Conventionally, as an insulated wire used for wiring of vehicles such as automobiles and electric / electronic devices, an insulated wire using a wire conductor in which a plurality of wires made of copper such as tough pitch copper are twisted is often used. .

  In recent years, performance of vehicles such as automobiles and electrical / electronic devices has been improved, and the number of insulated wires used tends to increase with an increase in various control circuits.

  Here, in the automobile field, a reduction in vehicle weight is desired from the viewpoint of energy saving and the like. Therefore, as part of reducing the vehicle weight, attempts have been made to reduce the weight of the insulated wires. For example, in a conventional insulated wire, since there is a surplus in current carrying capacity, the insulated wire is made lighter by reducing the diameter of the wire conductor.

  However, when the diameter of the wire conductor is reduced, there is a problem that the strength of the insulated wire is reduced. Thus, attempts have been made to improve the strength of insulated wires having a thin wire conductor.

  For example, Patent Document 1 discloses a wire conductor for an automobile configured by combining a plurality of strands made of stainless steel and a strand made of copper.

JP 2004-207079 A

  However, since stainless steel has a lower conductivity than copper, the strand made of stainless steel has a higher conductor resistance than the strand made of copper. For this reason, for example, if the wire conductor is pulled or repeatedly bent and the copper wire is disconnected first, the wire is likely to generate heat during energization.

  The problem to be solved by the present invention is to provide a wire conductor and an insulated wire that can improve strength reduction due to reduction in weight and diameter, and can suppress heat generation during energization even if it is disconnected. It is in.

  The electric wire conductor according to the present invention is an electric wire conductor formed by twisting a first strand made of a conductive material and a second strand made of a conductive material having lower conductivity and higher strength than the first strand. The second wire has a smaller elongation and a larger cross-sectional area than the first wire.

  In this case, the first strand is made of one or more materials selected from copper, copper alloy, aluminum and aluminum alloy, and the second strand is selected from iron, nickel and stainless steel. What consists of 1 type or 2 or more types of materials can be shown suitably.

  At this time, it is desirable that the wire conductor has an elongation of 15% or more.

  And it is desirable for the elongation rate of said 2nd strand to exist in the range of 50 to 95% of the elongation rate of said 1st strand.

  Furthermore, it is desirable that the entire cross-sectional area of the second strand is in the range of 10 to 90% with respect to the cross-sectional area of the wire conductor.

And the said wire conductor can be used especially suitably for the thin diameter electric wire whose cross-sectional area is 0.3 mm < ² > or less.

  Furthermore, the electric wire conductor may be circularly compressed.

  On the other hand, the gist of the insulated wire according to the present invention is that it uses the wire conductor.

  Since the electric wire conductor according to the present invention is formed by twisting the first element wire and the second element wire having higher strength than the first element wire, the conductor strength is higher than that of the electric wire conductor made of only the first element wire. Becomes higher. Thereby, for example, even when the wire conductor is made thin and lightened, the strength of the wire conductor is not easily lowered, so that the strength reduction accompanying the reduction in weight and diameter can be improved.

  Since the second strand has a smaller elongation and a larger cross-sectional area than the first strand, the first strand is applied when a tensile force is applied to the wire conductor or when the wire conductor is repeatedly bent. The second strand breaks before the line. As a result, when the first element wire is disconnected, the second element wire is disconnected. Therefore, even if the first element wire is disconnected during energization, a current is applied to the second element wire with low conductivity and high conductor resistance. It is possible to prevent the second strand from generating heat due to easy flow.

  In this case, the first strand is selected from one or more of copper, copper alloy, aluminum and aluminum alloy, and the second strand is selected from one, two or more of iron, nickel and stainless steel. By doing so, the above-described effects are surely achieved.

  At this time, when the elongation percentage of the wire conductor is 15% or more, for example, the wire conductor can be suitably used for an automobile wire.

  And when the elongation rate of said 2nd strand exists in the range of 50 to 95% of the elongation rate of said 1st strand, when tensile force is added to an electric wire conductor, it is reliably from a 2nd strand. Disconnect.

  Furthermore, when the cross-sectional area of the entire second strand is in the range of 10 to 90% with respect to the cross-sectional area of the wire conductor, the conductor strength is further improved.

And since it can use for the thin diameter electric wire whose cross-sectional area of an electric wire conductor is 0.3 mm < ² > or less, the weight reduction of an insulated wire can be achieved in the automotive field etc., for example.

  Furthermore, if the wire conductor is circularly compressed, the gap between the strands is reduced, so that the diameter of the wire conductor can be reduced when viewed with the same cross-sectional area.

On the other hand, since the insulated wire according to the present invention uses the wire conductor, the wire strength is high even if the wire conductor is made thinner. Moreover, even if the first strand breaks during energization, the second strand is broken first, so that heat generation of the wire is suppressed. And since electric wire intensity | strength is high, it can use suitably also for the thin diameter electric wire whose cross-sectional area of an electric wire conductor is 0.3 mm < ² > or less. Moreover, if the said insulated wire is used for the automotive field, for example, it can contribute to the weight reduction of a vehicle weight.

  Next, an embodiment of the present invention will be described in detail.

  The electric wire conductor according to the present invention is formed by twisting together a first element wire serving as a conductor and a second element wire serving as a reinforcing body that increases the strength of the electric wire conductor. The electric wire conductor is composed of one or more first strands and one or more second strands.

  The first strand is made of a conductive material. Examples of the conductive material include materials normally used as electric wire conductors such as copper, copper alloy, aluminum, and aluminum alloy. These may be either soft or hard. Although the elongation rate of a 1st strand is not specifically limited, For example, when using for the electric wire for motor vehicles, it is preferable that it is 15% or more. The elongation can be measured based on JIS C3002.

The cross-sectional area of the first strand is not particularly limited, but the weight of the electric wire can be reduced as the cross-sectional area is smaller. Therefore, for example, it is preferable to set it to 0.02 mm ² or less in consideration of the energization capacity. Further, the number of the first strands is not particularly limited, and may be determined in consideration of the cross-sectional area of one first strand and the energization amount.

  The second strand is a reinforcement that increases the strength of the electric wire conductor, and is formed of a material having a higher strength than the first strand. High-strength material means a material with a large elastic modulus and a high yield point stress. These are larger (higher) than the first strand, and therefore consist of only the first strand with the same diameter and number. The strength of the wire conductor composed of the first strand and the second strand is higher than that of the wire conductor.

  Examples of such materials include iron, nickel, and stainless steel. Since these materials have lower conductivity than the first strand, the conductor resistance is high. These materials may be either soft or hard. However, since the heat treatment temperature is generally high, it is preferable to use a soft heat-treated material because the heat treatment step of the second strand can be omitted.

  A more preferable material is stainless steel. This is because it is difficult to corrode and has excellent reliability in long-term use. Examples of stainless steel include SUS304 and SUS316.

  The second strand preferably has a smaller elongation than the first strand. This is because, for example, when a tensile force is applied to the wire conductor and a tensile stress is applied to the entire wire conductor, it becomes easier to break the wire earlier than the first strand. The elongation rate of the second strand is not particularly limited, but may be within a range of 50 to 95% of the elongation rate of the first strand in order to be surely broken before the first strand. preferable. In addition, when using for the electric wire for motor vehicles, it is preferable that the elongation rate of a 2nd strand is 15% or more.

  The second strand preferably has a larger cross-sectional area than the first strand. For example, when the electric wire conductor is repeatedly bent and subjected to bending stress throughout the electric wire conductor, it is easy to break the wire earlier than the first strand. In addition, when each strand maintains the circular cross section without circular compression of the whole electric wire conductor, you may compare not with a cross-sectional area but with a strand diameter. The number of second strands is not particularly limited. It is sufficient if the amount is sufficient to increase the strength of the wire conductor.

  The electric wire conductor is configured by combining the first strand and the second strand. Although it does not specifically limit as a combination, When the ratio of a 1st strand increases, intensity | strength will fall easily, but it will become easy to improve electroconductivity. On the other hand, when the proportion of the second strand increases, the conductivity tends to decrease, but the strength tends to improve. Therefore, it is preferable to combine the wires in consideration of conductivity and strength improvement effect.

  The ratio of the first strand (second strand) is represented by the cross-sectional area of the first strand (second strand) with respect to the cross-sectional area of the wire conductor. The cross-sectional area of the first strand (second strand) is represented by the cross-sectional area of the entire one or more first strands (second strand).

  Considering the conductivity and strength of the wire conductor, the ratio of the second strand is preferably in the range of 10 to 90%. More preferably, it is in the range of 10% to 50%. More preferably, it is in the range of 20% to 30%. This is because if it is less than 10%, the effect of improving the strength of the electric wire conductor tends to decrease. On the other hand, if it exceeds 90%, the conductor resistance tends to increase, so the allowable current of the wire tends to decrease, and if it exceeds 50%, the contact surface with the second strand increases when crimping with the terminal, This is because the contact resistance is likely to increase, so that heat is likely to be generated, making it difficult to use as a power line.

Although it does not specifically limit as a cross-sectional area of the whole electric wire conductor, It is preferable that it is 0.3 mm < ² > or less. This is because the wire weight can be reduced by reducing the diameter of the wire conductor. Further, even if the diameter of the electric wire conductor is reduced in this way, the strength can be maintained by the strength improvement effect. Note that the 0.3 mm ² or less, the cross-sectional area of the nominal, including those actual cross-sectional area is within the range of 0.08~0.38mm ^2.

  The wire conductor may be circularly compressed. Circular compression can be performed, for example, by passing the wire conductor through a compression die in a twisted state. When the electric wire conductor is circularly compressed, gaps between the strands are reduced, so that the diameter of the electric wire conductor can be reduced when viewed with the same cross-sectional area. In addition, the amount of coating can be reduced.

  Next, a more specific configuration of the electric wire conductor will be described with reference to FIGS.

  In FIG. 1, the electric wire conductor comprised by eight strands is shown. A wire conductor 10a shown in FIG. 1A is a combination example of seven first strands 12 and one second strand 14. A second strand 14 is disposed at the center, and seven first strands 12 are disposed so as to surround the second strand 14. The second strand 14 has a larger cross-sectional area than the first strand 12. An electric wire conductor 10b shown in FIG. 1B is obtained by circularly compressing the electric wire conductor 10a shown in FIG. Since the gap between the first strand 12 and the first strand 12 and between the first strand 12 and the second strand 14 is smaller than that of the wire conductor 10a, the wire conductor 10b is an electric wire. The diameter is smaller than that of the conductor 10a. Since the 2nd strand 14 is harder than the 1st strand 12, it is hard to be crushed rather than the 1st strand 12, and is maintaining the substantially circular shape.

  In FIG. 2, the electric wire conductor comprised by nine strands is shown. A wire conductor 20a shown in FIG. 2A is a combination example of eight first strands 12 and one second strand 14. A second strand 14 is disposed at the center, and eight first strands 12 are disposed so as to surround the second strand 14. The second strand 14 has a larger cross-sectional area than the first strand 12. An electric wire conductor 20b shown in FIG. 2B is obtained by circularly compressing the electric wire conductor 20a shown in FIG. Since the gap between the first strand 12 and the first strand 12 and between the first strand 12 and the second strand 14 is reduced as compared with the wire conductor 20a, the wire conductor 20b is an electric wire. The diameter is smaller than that of the conductor 20a. Since the 2nd strand 14 is harder than the 1st strand 12, it is hard to be crushed rather than the 1st strand 12, and is maintaining the substantially circular shape.

  In order to produce the wire conductor, for example, a desired number of first strands and second strands may be prepared and twisted together. At this time, cold processing such as wire drawing / compression or heat treatment may be performed before twisting or after twisting.

  The elongation of the first and second strands can be adjusted by cold working such as wire drawing / compression, heat treatment, material composition, and the like. Since work hardening is performed by cold working, the elongation of the strands can be reduced, and the elongation of the strands can be increased by heat treatment. The cross-sectional area can be adjusted by cold working such as wire drawing and compression.

  The first strand and the second strand may be adjusted to the intended elongation and cross-sectional area before being twisted, and the elongation and cross-sectional area are expected to change due to wire drawing, compression, heat treatment, etc. The material may be selected by (1) and may be adjusted to the desired elongation and cross-sectional area by wire drawing, compression, heat treatment, and the like after twisting.

  That is, a wire conductor may be formed by twisting a first strand and a second strand that have been adjusted in advance to the desired elongation and cross-sectional area, respectively, and the first strand and the second strand After twisting together, it may be adjusted to the desired elongation and cross-sectional area by performing cold working such as wire drawing / compression or heat treatment.

  As an example of adjusting the elongation and the cross-sectional area after twisting, for example, a copper element wire is a first element wire and a stainless steel element wire is a second element wire. After twisting one soft stainless steel wire adjusted to 7 and seven hard copper wires that have not been heat-treated, the elongation rate of the copper strand becomes higher than the elongation rate of the stainless steel wire It can be shown that heat treatment is performed.

  The heat treatment temperature is preferably in the range of 300 to 500 ° C. This is because if the temperature is lower than 300 ° C., work hardening due to cold working is difficult to remove, and thus it is difficult to obtain an effect of improving elongation. On the other hand, if the temperature exceeds 500 ° C., it is difficult to obtain an effect of improving the tensile strength.

  The heat treatment can be performed using various softening furnaces. The mode of the softening furnace is not particularly limited as long as desired characteristics are obtained for the wire conductor. It may be a batch type softening furnace or a continuous softening furnace. As a batch type softening furnace, a bell type softening furnace etc. can be illustrated, for example. On the other hand, examples of the continuous softening furnace include an energization continuous softening furnace, a pipe continuous softening furnace, and a high-frequency continuous softening furnace.

  Next, the insulated wire according to the present invention will be described.

  The insulated wire according to the present invention is formed by covering the outer periphery of the wire conductor with an insulator. The insulator may be a single layer or two or more layers. When two or more layers are used, each layer may be the same or different.

  Examples of the insulator include fluorine resins such as polyvinyl chloride, polyethylene, polypropylene, PFA resin, ETFE (ethylene tetrafluoroethylene copolymer) resin, and FEP (fluorinated ethylene propylene) resin. . The thickness of the coating is not particularly limited, but is preferably within a range of up to 0.2 mm, for example, to reduce the weight of the electric wire.

  Various additives may be blended in the insulator as necessary. Examples of such additives include antioxidants, metal deactivators, processing aids (lubricants, waxes, etc.) and the like.

  The insulated wire is, for example, an insulator material kneaded using a kneader that is usually used, such as an extruder (single axis, biaxial), a Banbury mixer, a pressure kneader, or a roll. The outer periphery of the electric wire conductor can be manufactured by extrusion coating.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto.

(Example 1)
7 soft copper strands with an elongation of 20-25% and strand diameter of 0.13 mm and a soft stainless steel strand (SUS304) with an elongation of 15-18% and strand diameter of 0.21 mm are twisted together An electric wire conductor was produced, and the outer circumference of the electric wire conductor was coated with a polyolefin blend with a thickness of 0.2 mm to produce an insulated electric wire.

(Example 2)
A wire conductor and an insulated wire were produced in the same manner as in Example 1 except that the number of the soft copper wires was eight.

  A tensile test and a bending test were performed on each insulated wire manufactured as described above. The results are shown in Table 1. In addition, each test method and evaluation method will be described below.

(Evaluation methods)
Electric wire tensile test It was performed according to JIS C 3002. That is, an insulated wire is cut into a length of 400 mm, and both ends of a test piece are attached to a chuck of a tensile tester at 23 ° C., and then pulled at a pulling speed of 200 mm / min. The broken wire was examined.

Conductor tensile test In place of the insulated wire, only the wire conductor in the insulated wire was subjected to a tensile test similar to the above-described wire tensile test.

Bending test The bending test was performed by the test method shown in FIG. That is, an insulated wire is cut to a length of 300 mm, a 500 g weight 34 is suspended at one end of the test piece 32 at 23 ° C., and the other end is bent at a bending radius R = 6 mm, a bending angle ± 90 °, and a bending speed is 1 round trip. / Sec. And repeatedly bent. One reciprocation was taken as one time, and the number of bendings was measured when the electrical conductor was no longer conducting (the wires were all disconnected). Moreover, in order to investigate the element | wire which disconnected previously, the test was stopped for every 100 times of bending | flexion, the electric wire coating | coated was peeled, and the presence or absence of the element | wire break was investigated.

  In Example 1 and Example 2, in the tensile test and the bending test, the stainless steel wire was disconnected first. That is, according to the wire conductor and the insulated wire according to the present embodiment, when a tensile force is applied to the wire conductor or when the wire conductor is repeatedly bent, the stainless steel wire is disconnected first. Therefore, since the stainless steel wire was already disconnected when the copper wire was disconnected, it was confirmed that current can easily flow through the stainless steel wire having a high conductor resistance and the stainless steel wire can be prevented from generating heat.

Moreover, the cross-sectional area of the electric wire conductor which concerns on a present Example was 0.14 mm < ² >, and the breaking load in the conductor tensile test was 60 N or more in both Examples. As a result, it was confirmed that the wire has a strength applicable to a thin wire having a nominal cross-sectional area of 0.3 mm ² or less, and it was confirmed that the strength reduction due to light weight and thinning can be improved.

  Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present invention.

  For example, in the embodiment, the wire conductor is formed in advance using a strand having a target elongation, but other than this, for example, a hard copper strand and a soft stainless strand are combined and twisted. It goes without saying that the same result can be obtained even if the copper wire is made to have a desired elongation by heat treatment. In the embodiment, the first strand is copper and the second strand is stainless. However, the first strand is made of a copper alloy, aluminum, or an aluminum alloy, and the second strand is iron, nickel, or Of course, the same result can be obtained even when it is made of stainless steel other than SUS304.

It is sectional drawing showing the electric wire conductor which concerns on one Embodiment of this invention, and is an electric wire conductor comprised by eight strands. It is sectional drawing showing the electric wire conductor which concerns on one Embodiment of this invention, and is an electric wire conductor comprised by nine strands. It is a figure explaining a bending test method.

Explanation of symbols

10a, 10b Wire conductor 20a, 20b Wire conductor 12 First strand (copper strand)
14 Second strand (stainless steel strand)

Claims (8)

A wire conductor formed by twisting a first strand made of a conductive material and a second strand made of a conductive material having lower conductivity and higher strength than the first strand,
The electric wire conductor, wherein the second strand has a smaller elongation and a larger cross-sectional area than the first strand.   The first strand is made of one or more materials selected from copper, copper alloy, aluminum and aluminum alloy, and the second strand is one or more selected from iron, nickel and stainless steel. It consists of 2 or more types of materials, The electric wire conductor of Claim 1 characterized by the above-mentioned.   The wire conductor according to claim 1 or 2, wherein the elongation is 15% or more.   The wire conductor according to any one of claims 1 to 3, wherein the elongation rate of the second strand is in a range of 50 to 95% of the elongation rate of the first strand.   The electric wire conductor according to any one of claims 1 to 4, wherein a cross-sectional area of the entire second strand is in a range of 10 to 90% with respect to a cross-sectional area of the electric wire conductor. The electric wire conductor according to any one of claims 1 to 5, wherein the cross-sectional area is 0.3 mm ² or less.   The wire conductor according to any one of claims 1 to 6, wherein the wire conductor is circularly compressed.   An insulated wire comprising the wire conductor according to any one of claims 1 to 7.

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