JPH0797456B2 - Method of manufacturing conductor for wiring - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for manufacturing a wiring conductor for equipment, in particular, a wiring conductor for which a pressure contact connector such as a flat type cable is used.

[Conventional technology]

In order to streamline the work of connecting cables and connectors, the range of applications of pressure-welded connectors that can be connected without removing the insulating film is expanding. As shown in Fig. 4, the U-shaped contact pin (4) is inserted into the cable (2) with the insulation film (3) and the gap between the U-shaped groove (5). The twisted conductor (1) in which the strands are twisted is sandwiched, and an electrical connection is obtained by the pressure contact force.

[Problems to be solved by the invention]

Conventionally, when such a crimping connector was used, Sn-plated annealed copper stranded wire was used for the cable conductor, but as shown in Fig. 5, the twisted conductor (1) is untwisted, resulting in sufficient connection reliability. There was a problem that could not be obtained. Therefore, the whole stranded wire was collectively coated with Sn as a conductor.
The use of Sn-coated annealed copper stranded wires and compressed conductors that have been diced after stranded wire and compressed into a circular cross-section have also become apparent.

However, since the Sn-coated annealed copper stranded wire is integrated with Sn, it has a property similar to that of a single wire, resulting in a problem that flexibility is deteriorated. Further, it is necessary to melt-coat an expensive Sn-plated annealed copper stranded wire, which causes a problem of cost increase.

The compression conductor has the advantage that it does not increase the cost because it is made by passing it through a drawing die when twisting the strands at the same time, but since it can compress only about 10% in terms of diameter ratio, The restraint was not sufficient, and the twist collapse could not be completely prevented, and the connection reliability was insufficient. In addition, the space factor remains low, and it has not reached the market demand for smaller diameter and lighter weight.

[Means for solving problems]

As a result of various studies in view of this, the present invention has improved the space factor, reduced the diameter and weight, and increased the contact area between the wires to enhance the restraint, thereby improving the reliability of the contact with the pressure welding connector. This is a method for manufacturing the wiring conductor that has been made possible by twisting the outer wires at least one layer along the longitudinal direction of the outer surface of each inner wire having a polygonal cross section, and then obtaining the stranded wire. It is characterized by being compression molded into a circular cross section.

That is, according to the present invention, as shown in FIG. 1, six outer strands (b) are twisted along the longitudinal direction of six side faces around a central strand (1a) having a hexagonal cross section, The whole wire is compression-molded into a circular cross section to obtain a conductor.

In this case, the outer strand does not need to have a circular cross section, but rather an elliptical strand is more suitable in terms of space factor after compression molding and connection reliability. Further, the central strand and the outer strand do not have to be made of the same material, and the compression moldability of the strand is better when the hardness of the central strand is higher than that of the outer strand.

The present invention has been described above with reference to an example in which six outer strands are twisted around one central strand as shown in FIG. 1, but the present invention is not limited to this, and for example, a cross section as shown in FIG. Eight outer wires (1b) may be twisted around the octagonal central wire (1a), and as shown in FIG. 3, around the central wire (1a) having a hexagonal cross section, Six intermediate wires (1
After c) is twisted and its outer peripheral surface is formed into a dodecagonal shape, 12 outer strands (1b) may be twisted as a second layer.

[Work]

As described above, the present invention makes the gap between the strands smaller by making the cross-sectional shape of the twisted surface of the inner strands for twisting the outer strands a polygon having sides equal to the number of outer strands. Further, since the contact area between the strands is increased, the restraining force between the strands is increased, and the twisting does not occur due to the shearing force when the compression connector is inserted. Also, since it is not integrated like the Sn-coated stranded wire, it exhibits moderate flexibility for ordinary bending.

〔Example〕

Six outer strands were twisted around a central strand having a hexagonal cross section, and subsequently compressed into a circular cross section using a die to manufacture the conductor according to the example of the present invention shown in FIG. That is, the Sn-plated phosphor bronze wire, which is a regular hexagon with a side length of 0.22 mm, is used as the central element wire, and the cross section has a major axis of 0.37 mm and a minor axis of 0.33 mm.
Approximately elliptical Sn-plated annealed copper wire is twisted, and then the outer diameter is
It was compressed into a circle of 0.96 mm. The space factor of this conductor was measured, and at the same time, the insulator was covered and inserted into a pressure contact connector to measure its contact resistance. The results are shown in Table 1 in comparison with the conductor according to the comparative example and the conductor according to the conventional example.

The contact resistance was measured by setting the number of n to 50 under each condition and applying a current of 2 amps to obtain the average value and standard deviation σ ₋₁ . The average value and the standard deviation of the contact resistance are expressed as a ratio, with the case of the conventional conductor being 1. As the conductor of the conventional example, an Sn-plated annealed copper stranded wire obtained by twisting seven Sn-plated annealed copper wires having a diameter of 0.32 mm was used, and the conductor of the comparative example had a diameter of 0.35 mm.
The conductor of the conventional example in which seven pieces of m-plated Sn-plated annealed copper wires were twisted together was circularly compressed to an outer diameter of 0.96 mm.

As is apparent from Table 1, the conductors of the examples of the present invention have a large space factor, and therefore, the current capacity can be increased with the same outer diameter, and the outer diameter can be reduced with the same current capacity.
In addition, since the binding force on the wire side is large, the twisting breakage when inserted into the press-connecting connector is small, and a dramatic improvement in connection reliability is recognized as compared with the conventional example and the comparative example.

〔The invention's effect〕

Since the conductor obtained by the present invention has a high space factor, it can sufficiently meet the demand for a smaller diameter, and since the twisting of the strands is less likely to occur, the connection reliability is high with a pressure welding connector, and equipment such as flat cables. Among them, the use of a wiring cable between devices as a conductor, an automobile cable, or the like has a remarkable industrial effect such as a reduction in assembly cost.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a conductor according to the present embodiment,
FIG. 2 is a cross-sectional view showing another embodiment of the conductor according to the present invention, FIG. 3 is a cross-sectional view showing yet another embodiment of the conductor according to the present invention, and FIG. FIG. 5 is a cross-sectional view showing a connection state of conductors, and FIG. 5 is a cross-sectional view showing a connection failure due to a pressure contact connector. 1. Twisted conductor 1a. Central strand 1b. Outer strand 1c. Intermediate strand 2. Cable 3. Insulation 4. U-shaped contact pin 5. U-shaped groove

Claims (1)

[Claims] 1. A stranded wire obtained by twisting at least one outer strand along the longitudinal direction of the outer surface of each inner strand having a polygonal cross section, and then compression-molding the resulting stranded wire into a circular cross section. And a method for manufacturing a wiring conductor.