JP2000251530A - Ultra-fine conductor for wiring material in movable portion - Google Patents

Abstract

PROBLEM TO BE SOLVED: To greatly improve tensile strength and bending resistance without causing reduction in conductivity. SOLUTION: In this ultra-fine conductor 1 for wiring material in a movable portion, a copper alloy formed by adding from 0.025 wt.% to 0.15 wt.% Mg and less than 0.20 wt.% Sn to Cu is extended and machined to less than 0.08 mm element wire diameter to form ultra-fine element wires 2 whose tensile strength is higher than 70 kg/mm2 and conductivity is higher than 70% IACS, and a plurality of these ultra-fine element wires 2 are stranded. Thus, tensile strength and bending resistance can be greatly improved without causing reduction in conductivity, and therefore, break or buckling is not caused for heavy bending stress.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrafine conductor for a movable portion wiring member used as a core wire of a movable portion wiring member wired to a movable portion of an electronic device such as a medical device or an industrial robot.

[0002]

2. Description of the Related Art Generally, a movable portion wiring member wired to a movable portion of an electronic device such as a medical device or an industrial robot has a stress such as severe bending, twisting, or tension due to its nature. In particular, the conductor serving as the core wire is required to have excellent bending resistance and tensile strength.

[0003] Therefore, recently, as a conductor used for such a movable portion wiring material, not only a soft copper wire but also Cu
An alloy material having improved tensile strength and bending resistance by adding an appropriate amount of Sn to the alloy has been developed, and has been partially commercialized.

On the other hand, in response to the recent demand for smaller, lighter, and higher-performance electronic devices, such movable section wiring members have been required to have smaller diameters for smaller and lighter weight and to increase the amount of information transmission. Although high conductivity has been demanded, at present, no small-diameter conductor that satisfies high conductivity as well as tensile strength and bending resistance has been proposed.

That is, when the above-mentioned conventional copper alloy is used as a material for a small-diameter conductor, it is necessary to further increase the addition amount of Sn in order to improve the tensile strength and the bending resistance accompanying the reduction in the diameter. However, there is a disadvantage that the conductivity is remarkably reduced, and it is impossible to satisfy all of tensile strength, bending resistance, and high conductivity at a high level.

Accordingly, the present invention has been devised in order to effectively solve such a problem, and an object of the present invention is to significantly improve the tensile strength and the bending resistance without lowering the conductivity. An object of the present invention is to provide a novel ultrafine conductor for a wiring member of a movable portion which can be made to work.

[0007]

In order to solve the above-mentioned problems, the present invention relates to a method for producing Cu containing 0.025 wt% or more of Mg and 0.15 wt% or less.
An ultra-fine wire with a tensile strength of 70 kg / mm ² or more and a conductivity of 70% IACS or more is formed by drawing a copper alloy containing less than 0.2 wt% of Sn and less than 0.20 wt% of Sn. Then, this ultrafine wire is formed by processing a plurality of stranded wires.

Accordingly, the tensile strength can be significantly increased and the bending resistance can be improved without lowering the conductivity, so that the tensile strength, the bending resistance and the conductivity are all satisfied at a high level. It becomes possible.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a preferred embodiment of the present invention will be described with reference to the accompanying drawings.

FIG. 1 shows an embodiment of an ultrafine conductor 1 for a movable portion wiring material according to the present invention.

As shown in the figure, the ultrafine conductor 1 for a movable portion wiring member has a strand diameter of 0.08 mm or less, preferably 0.1 mm or less.
It is formed by processing at least three or more stranded wires of an ultrafine wire 2 of not more than 05 mm, and the twist pitch is
The ratio is at least 10 to 25 with respect to the outer diameter of the conductor 1.

Here, the ratio between the pitch of the stranded wires and the conductor diameter is 10
The reason for limiting to ~ 24 is that if this ratio exceeds 24, the terminals of the stranded wire will be disintegrated at the time of terminal processing, it will be necessary to perform terminal processing by hand, and it will not be possible to automate terminal processing, If it is less than 10, the bending fatigue characteristics are generally improved, but in the case of a material having a small elongation such as hard copper wire, the amount of deflection applied to the strand during the twisting operation is increased, and the bending fatigue life is shortened. In addition, the speed at the time of the twisting operation is reduced, and the productivity is reduced. More preferably, the ratio between the twist pitch and the conductor diameter is in the range of 15-20. The reason why the ultrafine wire 2 is twisted is, of course, to improve the strength and the bending fatigue characteristics closely related to the strength. By the way, in the case of annealed copper wire, no matter how much it is twisted, satisfactory results regarding strength and bending fatigue characteristics cannot be obtained.

The ultrafine wire 2 is made of Cu containing MgO.
025 wt% or more and less than 0.15 wt%, and Sn in an amount of 0.
A copper alloy to which 20 wt% or less is added is cold drawn to a wire diameter of 0.08 mm or less, and has a tensile strength of 70 kg /
It exhibits high tensile strength and electrical conductivity of not less than ² mm ² and electrical conductivity of 70% IACS or more.

Here, the addition amount of Mg is set to 0.025-0.
The reason why the content is limited to 15 wt% is that even if the content is 0.025 wt% or less, the conductivity is high and there is no problem, but the tensile strength is insufficient and a high tensile strength of 70 kg / mm ² or more cannot be obtained. If the content exceeds 0.15 wt%, Mg is an active metal, so that MgO is easily generated, which causes disconnection during wire drawing. The reason why the amount of Sn added is set to 0.20 wt% or less is that if it exceeds 0.20 wt%, the conductivity is remarkably reduced, and a high conductivity of 70% IACS or more cannot be obtained. Further, the reason why the tensile strength is 70 kg / mm ² or more is that if it is less than that, sufficient bending resistance cannot be obtained, and the conductivity is 70% IACS or more. This is because the characteristics as a highly conductive conductor cannot be obtained as compared with the related art.

The ultra-fine conductor 1 for a movable portion wiring material of the present invention having the above-described structure can exhibit excellent tensile strength and bending resistance without lowering the conductivity. In addition, excellent productivity and reliability can be exhibited without inconvenience such as twisted wire breakage during terminal processing.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described.

A copper alloy to which Mg and Sn or Sn alone are added at various concentrations is cold drawn to φ0.04 mm to process ultrafine wires, and then, using these seven ultrafine wires, A plurality of types of ultrafine conductor samples were formed by twisting at various pitches. Thereafter, a flex life test was performed on these plural kinds of ultrafine conductor samples, and the results are shown in Table 1 below.

[0018]

[Table 1]

As a result, as shown in Table 1, Mg and Sn
In the case of the samples according to Examples 1 to 4 in which both the amount of addition and the pitch / conductor ratio are within the scope of the present invention, the flex life greatly exceeds 1000 times, and the tensile strength and the conductivity All exhibited high numerical values, and all of the flex resistance, tensile strength, and conductivity value were satisfied with high dimensions. In addition, it was found that there was no occurrence of stranded wire variation at the time of terminal processing, and excellent workability was exhibited.

On the other hand, in the case of the samples of Comparative Examples 1 and 2 made of the conventional Sn—Cu alloy to which no Mg is added, the flex life is low and the flex resistance is poor. In addition, the sample of Comparative Example 3 in which the amount of Sn added was further increased showed a good value in terms of flex resistance, but had a low conductivity of 65% IACS, which was a practically satisfactory value. Was not obtained.

Further, although the addition amounts of Mg and Sn are within the range of the present invention, in Comparative Example 4 in which the pitch / conductor ratio is less than the range of the present invention, the bending resistance is inferior. In Comparative Example 5, in which the pitch / conductor ratio exceeded the range of the present invention, all of the flex resistance, tensile strength, and electrical conductivity showed high values, but the twisted wire was uneven during terminal processing. In short, the workability was poor.

Incidentally, in parallel with this test, any one of silver plating, tin plating, and nickel plating was previously applied to each strand 2 of the microfine conductor 1 according to the present invention before the stranded wire was processed. Effective solderability was also confirmed.

[0023]

In summary, according to the present invention, the tensile strength and the bending resistance can be greatly improved without sacrificing the conductivity. As a result, tensile strength, flex resistance,
All of the high conductivity can be satisfied at a high level. The use of such an ultrafine conductor for a movable portion wiring material according to the present invention can greatly contribute to a reduction in size, weight, and performance of a medical device, an electronic device, and the like, and a movable portion thereof. Excellent effects can be exhibited.

[Brief description of the drawings]

FIG. 1 is an enlarged side view showing one embodiment of the present invention.

[Explanation of symbols]

 1 Ultrafine conductor for wiring material of movable part 2 Extrafine wire

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masayoshi Aoyama 5-1-1 Hidaka-cho, Hitachi City, Ibaraki Prefecture Power Systems Research Laboratory, Hitachi Cable, Ltd. (72) Inventor Hitoshi Ueno 5 Hidaka-cho, Hitachi City, Ibaraki Prefecture No. 1-1, Hitachi Cable Co., Ltd. H-Taka Plant F term (reference) 5G301 AA01 AA08 AA12 AA14 AA20 AB02 AB05 AD01 5G307 EA01 EB06 EC03 EF09 EF10

Claims (4)

[Claims] 1. An alloy containing 0.025 wt% or more of Mg and 0.1 wt.
An ultrafine wire having a tensile strength of 70 kg / mm ² or more and a conductivity of 70% IACS or more is formed by drawing a copper alloy containing less than 5 wt% and Sn added at 0.20 wt% or less to a wire diameter of 0.08 mm or less. An ultrafine conductor for a movable portion wiring material, wherein a plurality of the ultrafine wires are processed by twisting. 2. The movable part wiring according to claim 1, wherein the wire diameter of the ultrafine wire is 0.05 mm or less, and at least three or more of the ultrafine wires are processed by twisting. Extra fine conductor for materials. 3. The method according to claim 1, wherein the ratio between the twist pitch of the ultrafine wires and the conductor diameter is 10 to 24.
4. The ultrafine conductor for a movable portion wiring material according to claim 1. 4. The movable part wiring material according to claim 1, wherein one of silver plating, tin plating, and nickel plating is applied to an outer periphery of the ultrafine wire. Extra fine conductor.