JPH0158728B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an improved method for effectively and accurately clamping electric wires having stepped surfaces.

[Prior Art] As a low wind noise or low corona noise (low AN) type electric wire, an electric wire 10 as shown in FIG. 2 has been proposed and is being put into practical use. That is, the outermost stranded wire layer of the electric wire 10 is made of wires 11 having a large width in the radial direction of the electric wire.
The electric wire 10 is composed of small-width strands 12, and peaks 10a and troughs 10b are formed on the outer periphery of the electric wire 10 to disturb the periodicity of the air fluid around the outer periphery of the electric wire, thereby achieving the desired effect. .

When fixing a wire with such a cross-sectional shape using a suspension clamp, spacer clamp, wedge-type clamp, bolt-type clamp, or come-along, the inner surface of the clamp part has a circular cross-section. contacts only the peak 10a, and if the circumferential surface of the peak 10a is small, not only will the tightening force be insufficient, but there is a risk of damaging the peak 10a. Therefore, in order to prevent such problems, a suitable plate-shaped aluminum collar is interposed in the valley portion 10a, and the entire outer periphery of the electric wire is adjusted to a circular cross section equal to the outer diameter of the peak portion 10, and the wire is clamped. I have already suggested. However, when this was actually applied, it was found that there were many problems. In other words, the twist pitch of wires that are twisted together to form peaks and valleys fluctuates due to changes in tension during stranding and tension during wire drawing, and the alignment of the wires becomes disordered, causing the aluminum collar to change. They may not mesh well as planned, but there may also be problems with dimensional accuracy, making it impossible for the aluminum collar to fit.

Therefore, if a similar outer circumference adjustment is made by winding a plurality of spiral rods with a circular cross section in the valley instead of the plate-shaped aluminum collar, a degree of freedom will be created in terms of dimensions, and the outer circumference of the stranded wire will be increased. I found that it fits well.

[Problems to be Solved by the Invention] As described above, by winding and interposing the spiral rod in the trough, the situation in which it could not be interposed due to dimensional errors was solved, but the outer diameter of the electric wire used in practical use is generally around 30 mm, and the height difference between the peaks and valleys formed in such electric wires is at most 1.5 to 2.5 mm.
Therefore, the diameter of the strands required to fill the valleys becomes substantially thinner. When winding a spiral rod with such a small diameter, the spiral rod itself has no stiffness, so it easily deforms due to external force, resulting in a flattened state or the end of the rod protruding from the wire. It was found that there are still problems that need to be solved, such as becoming a point of electric field concentration and causing corona generation.

[Means for Solving the Problems] The present invention has been made in view of the above-mentioned circumstances, and its gist is to clamp and fix an electric wire having a non-circular cross section having peaks and valleys on the outer peripheral surface. In this case, thin strands are placed in the areas that will become peaks, and thick strands are placed in areas that will become troughs, so that almost the entire circumference forms a circular outer surface. The diameter of the outer periphery formed by the wires arranged on the side with the larger circumference is slightly larger than the diameter of the outer periphery formed by the strands arranged on the side with the smaller circumference. A method of clamping and fixing an electric wire with a non-circular cross section by forming and fixing the wire with a clamp.

[Function] With the above configuration, the diameter of the wire of the spiral rod can be selected as required without being restricted by the size of the step between the peak and valley of the wire. Since you can select a rod with strong strength and so-called firmness, you can avoid troublesome situations such as the wire being tightly wrapped around the wire and the terminal popping out, and the rod with a larger circumference is more durable. By abutting with contact force, the clamp itself is fixed in a well-balanced manner.

[Example] This will be explained below based on examples.

Although FIG. 1 is shown as a somewhat exaggerated diagram, the electric wire 10 has a peak portion 10a and a valley portion 10b.
Spiral rods 2, 2 with a thick wire diameter are wound around the trough 10b, spiral rods 1, 1 with a thin wire diameter are wound around the crest 10a, and the spiral rods 1, 1 are wound around the crest 10a with a small circumference. The diameter B of the outer periphery formed by the rods 1, 1 is slightly smaller than the diameter A of the outer periphery formed by the rods 2, 2 wound around the valley portion 10b having a large circumference, that is, the relationship A>B. It is gripped and fixed by a clamp 20 schematically indicated by a dashed line.

As already explained, the diameter of the spiral rod is selected to have sufficient strength.
There is no risk of the strands falling or sagging due to external force, and since the strand 2 with the larger circumference has been selected to be clamped more firmly, the side with the smaller circumference should be clamped. This also prevents the screws from becoming insufficiently tightened.

When tightening with a clamp in this manner, it is desired that the inner surface of the clamp 20 be in contact with the entire circumference, so the difference between A and B should not be too large. It is desirable that the larger spiral rod on the A side undergoes some plastic deformation and elastic deformation due to tightening by the clamp 20, and that all the spiral rods come into contact with the inner surface of the clamp 20. The difference is 0.2~0.5mm
It is best to choose the appropriate amount.

What is shown in FIG. 3 is an example of actual dimensions when the present invention is applied to a practical size low-pitched AN type 930 mm ² ACSR. As a result of clamping with this configuration, it has been demonstrated that extremely stable and strong tightening can be achieved.

Note that the shapes of the spiral rod and the strands of the electric wire are merely exemplary, and are not limited to these, and it goes without saying that an appropriate cross-sectional shape can be selected.

[Effects of the Invention] As described above, according to the clamp fixing method of the present invention, electric wires having stepped surfaces can be strongly tightened in a stable state, and the spiral rod itself does not loosen or sag, so it is electrically stable. becomes. Furthermore, as a result of covering the entire circumference of the wire in the clamp portion with a spiral rod, it also has additional effects, such as preventing the surface of the wire from being damaged by arcs caused by lightning strikes, etc. Nowadays, the present invention has great significance as there is an increasing demand for electric wires having a special shape having a stepped surface.

[Brief explanation of drawings]

Fig. 1 is a schematic explanatory diagram of the clamp part according to the present invention, Fig. 2 is a sectional view showing an example of an electric wire having a stepped surface, and Fig. 3 is an explanation of actual dimensions of a specific example to which the invention according to the present invention is applied. It is a diagram. 1, 2: Spiral rod, 10: Electric wire, 10
a: crest, 10b: trough, 20: clamp piece.

Claims (1)

[Claims] 1. When clamping and fixing an electric wire with a non-circular cross section that has peaks and valleys on its outer peripheral surface, a thin wire is placed in the peaks and a thin wire is placed in the valleys. thick strands are arranged so that almost the entire circumference forms a circular outer peripheral surface, and the diameter of the outer periphery formed by the strands arranged at the peaks or valleys, whichever has the larger circumference, is A method for clamping and fixing an electric wire with a non-circular cross section, in which the wire is formed to have a diameter slightly larger than the diameter of the outer periphery formed by the strands arranged on the smaller side of the circumference, and then the wire is clamped. 2 The difference between the larger diameter and the smaller diameter of the outer circumference is
A method for clamping and fixing a non-circular cross-sectional electric wire according to claim 1, wherein the wire has a diameter of 0.2 to 0.5 mm.