JPS60157110A - Method of producing slackness suppression type wire - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Background and purpose of the invention] The present invention relates to a method for manufacturing a slack-reduced electric wire.

Electrical wires made of stranded wires of steel core and aluminum wire are well known and are generally used as overhead wires in which the two are twisted together and there is no relative sliding movement. In such a case, due to the difference in linear expansion coefficient between the two, the tension is not distributed only to the steel core, but the temperature rise due to energization changes the condition of the overhead wire, increasing the sag and reducing the current capacity accordingly, which is inconvenient. be. To this end, a so-called sag-reducing structure has been proposed in which a small gap is created between the steel core and the aluminum wire to allow relative sliding between the two. An example of this is JP-A No. 5
8-80211, in which an electric wire is manufactured by placing a water-soluble intermediary on the steel core to create a gap between the steel core and the aluminum stranded wire, and then eluting it to close the gap. A method of providing this information has been proposed. Although this method is effective, there is a high possibility that inclusions will remain between the two, resulting in the problem of corrosion of the wire. Some materials use materials that have anti-corrosion properties, but such materials are relatively soft and it is difficult to reliably leave the desired gap between the steel core and the aluminum strands.

On the other hand, there is a method that uses a hardened string or tape of an anticorrosive grease-like substance as an interposition, and this is an extremely effective method. To do so is currently quite difficult.

An object of the present invention is to provide a method for manufacturing a slack-reducing electric wire that can reliably and easily create a gap between a steel core and an aluminum stranded wire.

[Summary of the invention]

According to the present invention, this is achieved by applying anticorrosive grease made of a relatively soft material to the outer periphery of the steel core, solidifying it, and then twisting the aluminum wire thereon.

〔Example〕

FIG. 1 is a schematic diagram of an apparatus for carrying out the method of the invention, and FIG. 2 is a sectional view of the resulting wire in its uncoated state.

1 and 2, a suitable number of steel wires 1 are twisted together using a steel wire twisting machine 4 to make a steel core, and this steel core is passed through a grease applicator 5 to coat it with anti-corrosive soft grease. Apply to its outer periphery. The steel core coated with grease in this manner is passed through a grease hardening device 6. The grease curing device 6 may be a cold air device, and by blowing cold air onto the grease, the anticorrosive grease is solidified to form a grease layer 2 which also serves as an intervening layer.

The steel core on which the grease layer 2 has been formed in this manner is twisted together with the aluminum wire 3 on the grease layer 2 in the aluminum stranded wire a7, and is appropriately coated to form an electric wire.

A solidified grease layer 2 is interposed between the steel core and aluminum wire of the electric wire formed in this way, and even if this grease subsequently softens, a gap remains between the two to allow relative movement. Thus, a slack-reduced electric wire can be easily manufactured.

We have described the method of curing anticorrosive grease by blowing cold air, but for example, it is also possible to place an ultra-compact cooler that uses compressed air in the production line and pass a steel core through the gib for blowing cold air. In this way, it is possible to downsize the manufacturing apparatus itself. Furthermore, depending on the dimensions of the electric wire, it is also possible to adjust the thickness of the grease using a drawing die so that it becomes the thickness necessary for suppressing sag after appropriately applying the grease.

〔Effect of the invention〕

According to the present invention, it is extremely easy to form a gap between the steel core and the aluminum stranded wire, and therefore it is possible to easily and reliably manufacture a slack-reducing electric wire. Because of this, corrosion of the aluminum stranded wire does not progress.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of an apparatus for carrying out the method of the invention;
FIG. 2 is a sectional view of a slack-suppressing electric wire according to the present invention. l...Steel wire, 2...Grease layer, 3...Aluminum stranded wire,
4... Steel wire twisting machine, 5... Grease application device, 6...
・Grease hardening device, 7... Aluminum wire twisting machine. taste 1 day

Claims (1)

[Claims] In the production of steel-core aluminum stranded wire, which consists of twisting a plurality of aluminum wires around the circumference of a steel core, anti-corrosion grease is applied to the outer circumference of the steel core, and the aluminum wires are twisted while the grease is solidified. A method for manufacturing a slack-suppressing electric wire, comprising forming a gap with grease between the steel core and the aluminum wire.