JP2006339040A

JP2006339040A - Composite electric cable

Info

Publication number: JP2006339040A
Application number: JP2005162764A
Authority: JP
Inventors: Yasunori Hattori; Masayoshi Tadano; Yukio Uchida; 幸夫内田; 政義多々納; 保徳服部
Original assignee: Nisshin Steel Co Ltd; 日新製鋼株式会社
Priority date: 2005-06-02
Filing date: 2005-06-02
Publication date: 2006-12-14

Abstract

An electric wire having excellent flexibility and tensile strength that can be used as a substitute for a copper twisted wire in a wire harness, particularly in connection with a harness plug, having excellent resistance to disconnection of a crimping portion, and in the crimping portion. The present invention provides an electric wire that does not contain copper and that can suppress the heat generation of electricity.
A composite electric wire having a plurality of aluminum wires in the center and a plurality of hot-dip aluminum-plated iron wires around the center. As the aluminum wire, one having a diameter of 0.12 to 1.5 mm can be applied, and as the molten aluminum plated iron wire, an aluminum wire having a diameter of 0.1 to 2.0 mm is used as a core material, and a molten aluminum plating of 30 g / m ² or more is applied. Applicable ones can be applied. Moreover, the thing with which following (1) Formula is materialized between the number a of the said aluminum wire and the number b of the hot-dip aluminum plating iron wire becomes a preferable object.
0.2 ≦ b / a ≦ 0.5 (1)
[Selection figure] None

Description

The present invention relates to a composite electric wire in which metal wires made of different kinds of materials are arranged at the center and the periphery, and particularly relates to an electric wire suitable for a wire harness.

Many electrical components are used in electrical equipment, automobiles, etc., and each electrical component is electrically connected by wiring a wire harness consisting of multiple wires, multiple connectors, etc. in the equipment or vehicle. It is connected. Electric wires used in this wire harness are mainly made of twisted copper wires. However, in recent years, there has been a review of the wire harness material for this wire harness.

That is, there is an increasing need for weight reduction in automobiles and various electric devices. Since the wire harness has a considerable weight, it is strongly desired to adopt a light material such as aluminum instead of copper having a large specific gravity. In addition, laws on the recycling of household electrical appliances and automobiles have been enacted, and importance has been placed on the separate collection of copper. In particular, for automobiles, it is necessary to reduce the copper content to 0.3% or less in the “all-recycling” process in which the so-called “gara” of scrap cars is pressed and used in an electric furnace. From these things, the electric wire for wire harnesses is also shifting from a copper wire to an aluminum wire.

Aluminum has the second highest electrical conductivity after copper, is excellent in wire drawing workability, and is lightweight, so it has been used as a wire material mainly for applications in overhead power transmission lines and overhead distribution lines. ing. In the case of an aluminum electric wire, in order to ensure the same conductivity as that of a copper wire, it is necessary to increase the cross-sectional area by about 1.3 times. In order to improve the strength level of the electric wire as a countermeasure, a “steel core aluminum stranded wire” in which a steel wire is arranged at the center of the cross section of the aluminum stranded wire is used, and various improvements have been attempted (Patent Documents). 1).

On the other hand, an aluminum stranded wire has lower durability against “bending” than a copper stranded wire, and is more likely to break when subjected to severe bending. For this reason, it is not always easy to apply an aluminum twisted wire for wire harness applications. For example, a special bending mechanism has been proposed in a portion subjected to severe bending (Patent Document 2). Moreover, the aluminum stranded wire also has a defect that disconnection at the crimping portion is more likely to occur than the copper stranded wire.

JP 2001-195925 A Japanese Patent Laid-Open No. 2004-247053

In view of such a current situation, the present invention is an electric wire having excellent flexibility and tensile strength that can be used as a substitute for a copper stranded wire in a wire harness, and in particular, a disconnection resistance of a crimping portion in connection with a harness plug It is intended to provide an electric wire that does not contain copper and is excellent in electrical resistance and heat generation at the crimping part.

The above object is achieved by a composite electric wire having a plurality of aluminum wires in the center and a plurality of hot-dip aluminized iron wires around it.
As the aluminum wire constituting the central portion, for example, a wire having a diameter of 0.12 to 1.5 mm can be applied, and as the molten aluminum plated iron wire constituting the periphery, for example, an iron wire having a diameter of 0.1 to 2.0 mm is used as a core material. A material subjected to hot dip aluminum plating can be applied.

Also, a preferable object is that the following equation (1) is established between the number a of the aluminum wires constituting the central portion and the number b of the hot-dip aluminum-plated iron wires constituting the periphery thereof.
0.2 ≦ b / a ≦ 0.5 (1)

The adhesion amount of the molten aluminum plating per one molten aluminum plated iron wire is preferably 30 g / m ² or more. Here, the “m ² ” is a unit surface area of the hot-dip aluminized iron wire before plating. Moreover, what the Si content in an aluminum plating layer is 0-15 mass% is applicable to the said molten aluminum plating iron wire. Here, the lower limit of Si content is 0% when the Si content is below the measurement limit in a normal analysis method in a hot dipping line, and for example, so-called pure aluminum plating corresponds to this. In the case where Si is contained in the aluminum plating layer, those having a Si content of 2 to 15% by mass are preferred.

Although the composite electric wire of the present invention is an electric wire mainly composed of aluminum (hereinafter referred to as “aluminum-based electric wire”), disconnection at a bent portion or a terminal crimping portion hardly occurs. For this reason, it can be used for a wire harness as it is without providing a special bending mechanism. In addition, since the tensile strength is improved, the wire harness manufacturing stage and the handleability when the wire harness is incorporated into an automobile or the like are excellent. It also has excellent corrosion resistance, and heat generation at the crimp terminal can be kept low. Therefore, the present invention brings about cost reduction and reliability improvement of wire harnesses composed of aluminum-based electric wires, and contributes to recycling and weight reduction of electrical equipment and automobiles through the widespread use of wire harnesses that do not use copper wires. Can do.

As described above, steel core aluminum stranded wires have been put into practical use in order to supplement the strength level of aluminum-based electric wires. However, since the steel core aluminum stranded wire uses a steel wire, it is disadvantageous in terms of conductivity. Further, the outermost layer of the metal member responsible for energization is the same as an electric wire made of only an aluminum wire in that it is made of an aluminum wire. For this reason, when the steel core aluminum stranded wire is used for an application in which bending bending or crimping is performed, the aluminum wire constituting the outermost layer is easily damaged and does not lead to drastic improvement in breakage resistance.

As a result of various studies, if the outermost layer of the metal member responsible for energization is composed of a metal wire with a high strength level, the inventor will bend even if a relatively low durability material such as an aluminum wire is placed inside. It has been found that the breakage resistance against bending and crimping can be greatly improved. An example of such a high-strength metal wire is iron wire. However, what is satisfactory in a wire harness use cannot be obtained only by using a stranded wire covered with iron wire.

That is, if the outermost layer of the metal member is made of iron wire, sufficient reliability cannot be ensured in terms of corrosion resistance. Further, if the inner aluminum wire is covered with a sufficient amount of iron wire so that it is not exposed to the outermost layer, the conductivity will be poor. Furthermore, since the contact portion with the crimp terminal is electrically connected via a high-resistance iron wire, local heat generation is also a concern. Accordingly, it is not always easy to employ a method of reinforcing the outermost layer with a high-strength metal wire in an aluminum-based electric wire.

Therefore, the inventors proceeded with further detailed research. As a result, it has been found that when a hot-dip aluminum plated iron wire is used as the high-strength metal wire disposed in the outermost layer, the disconnection resistance can be remarkably improved without the above-described problems becoming apparent. That is, in the present invention, a twisted wire structure having a plurality of aluminum wires at the center and a plurality of hot-dip aluminum-plated iron wires around the center is adopted.

As the aluminum wire constituting the center, one having a diameter of 0.12 to 1.5 mm can be adopted, and one having a diameter of 0.14 to 0.8 mm is more preferable for an automobile wire harness. In terms of material, an aluminum wire equivalent to an existing aluminum stranded wire can be adopted.

As the hot-dip aluminum-plated iron wire constituting the periphery, a hot-dip aluminum plated wire having a diameter of 0.09 to 1.9 mm as a core material can be adopted. What plated the core material with a diameter of 0.13-0.7 mm is still more preferable for the wire harness for motor vehicles. The iron wire used as the core material can be a normal iron wire as shown in JIS G3532, but from the viewpoint of conductivity, it is preferable to reduce impurities as much as possible.

As for the adhesion amount of the molten aluminum plating per iron wire, it is desirable to ensure 30 g / m < ² > or more. If the amount is less than this, there is a high possibility that iron is exposed at the crimped portion or the portion that has been bent and bent, and the problems of corrosion resistance deterioration and contact resistance increase are likely to become apparent. In addition, the ratio of iron in the cross section of the wire increases, leading to a decrease in conductivity. If possible, the adhesion amount of aluminum plating is preferably 40 g / m ² or more. The upper limit of the aluminum plating adhesion amount is not particularly limited, but generally good results are obtained in the range of 200 g / m ² or less. The hot dip aluminum plating method may follow a general continuous plating method for wire.

It is preferable that the ratio of the aluminum wire and the galvanized iron wire satisfies the following formula (1) in the number ratio.
0.2 ≦ b / a ≦ 0.5 (1)
Where a is the number of aluminum wires, and b is the number of hot-dip aluminized iron wires.

In order to obtain the composite electric wire of the present invention using the wires as described above, a plurality of aluminum wires constituting the central portion are twisted together according to a general method for producing a twisted wire, and a plurality of wires are disposed around the aluminum twisted wire. What is necessary is just to twist together the said hot-dip aluminum plating iron wire.

The composite electric wire thus obtained can be used for a wire harness in place of a conventional copper stranded wire.

The following three types of stranded wires were manufactured. These have similar shapes and sizes to which the same type of crimp terminals can be applied.
[Stranded wire A]
The composite electric wire of the example of the present invention.
Ten aluminum wires having a diameter of 0.2 mm were twisted in accordance with a general stranded wire manufacturing method to form a “central stranded wire”.
On the other hand, a hot-dip aluminum-plated iron wire was prepared by applying hot-dip aluminum plating with an iron wire having a diameter of 0.14 mm (equivalent to a normal iron wire of JIS G3532). The molten aluminum plating conditions are as follows: bath composition: 2.5 mass% Si, balance Al and inevitable impurities, bath temperature: 680 ° C., atmosphere exposed to the iron wire immediately before dipping in the bath: 50% H ₂ —N ₂ gas, Bath immersion time: 1 second, plating adhesion amount control: electromagnetic wiping method was performed on a continuous plating line.
Seven galvanized iron wires thus obtained were twisted around the central stranded wire to obtain a stranded wire A.

[Stranded wire B]
Comparative aluminum stranded wire.
17 aluminum wires having a diameter of 0.2 mm were twisted in accordance with a general twisted wire manufacturing method to obtain a twisted wire B.

[Stranded wire C]
The copper twisted wire of a comparative example. It is similar to what is used frequently in current wire harnesses.
17 copper wires having a diameter of 0.15 mm were twisted together according to a general twisted wire manufacturing method to obtain a twisted wire C.

(Disconnection resistance test)
Five types of crimp terminals generally used for wire harnesses were prepared. The same kind of crimp terminals were attached to both ends of a short sample electric wire obtained by cutting each stranded wire. At that time, the distance between both terminals was set to 10 mm. After fixing one of the terminals with a vise, grasp the other terminal with pliers and slowly apply the terminal grasped with the pliers to the longitudinal direction of the wire while applying a light tension so that the wire does not loosen between the terminals. The twist angle when at least one of the strands constituting the stranded wire near the terminal was disconnected (hereinafter referred to as “disconnection torsion angle”) was measured. Such a test was conducted by the same tester 10 times for each of the same type of terminals on the stranded wires A to C. That is, for each stranded wire, 5 types of terminals × 10 times = a total of 50 samples were prepared and the torsion test was performed.

As a result, in the comparison for each terminal of the same type, the average breakage twist angle (°) in each case was stranded wire A ≧ stranded wire C> stranded wire B. That is, it was confirmed that the composite electric wire of the present invention has a breakage resistance equal to or higher than that of a conventional copper stranded wire.

[Energization test]
Five types of crimp terminals generally used for wire harnesses were prepared. About the twisted wire A of this invention and the twisted wire C which is a copper twisted wire, the sample electric wire of length 300mm was prepared, and the same kind crimp terminal was attached to the both ends. At that time, one terminal was attached by crimping a thermocouple together with the electric wire (twisted wire). Terminals fitted to the crimp terminals were prepared, and lead wires were attached thereto. Then, both terminals of the sample electric wire were joined to the terminals with the lead wires, respectively, to constitute an electric circuit, and a current of 5 A was passed through the sample electric wire via a load by a 24 V DC power source. After the start of energization, the temperature when the temperature measured by the thermocouple became constant was read, and the degree of heat generation at the terminal portion was evaluated. Such a test was performed 10 times for each of the same type of terminals on the stranded wires A and C. That is, for each stranded wire, 5 types of terminals × 10 times = total of 50 samples were prepared and the energization test was performed.

As a result, in the comparison for each terminal of the same type, in each case, the average heat generation temperature was twisted wire A ≧ twisted wire C, and there was almost no difference between them, or that of the present invention was slightly higher. However, even in the case of the present invention example in which the average heat generation temperature was slightly high, the difference was slight, and the heat generation level was sufficient for practical use. Rather, considering the results of the disconnection resistance test, it is considered that the composite electric wire of the present invention is less likely to be disconnected under severe usage conditions, and is more reliable in terms of heat generation.

Claims

Composite electric wire with multiple aluminum wires in the center and multiple hot-dip galvanized iron wires around it.
The aluminum wire constituting the central portion has a diameter of 0.12 to 1.5 mm, and the molten aluminum plated iron wire constituting the periphery thereof has been subjected to molten aluminum plating with an iron wire having a diameter of 0.1 to 2.0 mm as a core material. The composite electric wire according to claim 1.
The composite electric wire according to claim 1 or 2, wherein the following expression (1) is established between the number a of the aluminum wires constituting the central portion and the number b of the molten aluminum-plated iron wires constituting the periphery thereof.
0.2 ≦ b / a ≦ 0.5 (1)
The composite electric wire according to claim 1, wherein an adhesion amount of the molten aluminum plating per one of the molten aluminum plated iron wires is 30 g / m ² or more.
5. The composite electric wire according to claim 1, wherein the molten aluminum-plated iron wire has an Si content in an aluminum plating layer of 0 to 15% by mass.
5. The composite electric wire according to claim 1, wherein the molten aluminum-plated iron wire has an Si content in an aluminum plating layer of 2 to 15 mass%.
The composite electric wire according to claim 1, wherein the composite electric wire is used for a wire harness.