JPS624803B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a watertight electric wire manufacturing method.

Conventionally, watertight electric wires have been manufactured as shown in FIG. That is, a twisting die 2 that twists together seven strands 1 to form a strut, for example, a seven-core twisted wire;
At each entrance side of the twisting die 3, which twists 12 wires onto a 7-core twisted wire to form an electric wire, tape-shaped watertight materials 4 and 5 are supplied to the assembled wires, respectively. A gas burner is placed on the inlet side of the die to heat it, melting the tape-shaped watertight material and permeating it between the strands.

In the conventional method described above, the watertight material is processed into a tape shape, which may result in high costs. Also,
When processing a watertight material into a tape shape, it is difficult to make the tape thinner than a certain limit, so the thickness may become too thick relative to the amount of filling in the electric wire, and there is a risk of loss of watertight material. Further, excessive watertight material may adhere to the surface of the electric wire, causing unevenness on the surface. Furthermore, since the wire is heated by a gas burner at the inlet of the twisting die, the hard wire may be softened and its tensile strength may be reduced. Moreover, there is a possibility that the wire may change color due to heating.

Furthermore, there was a drawback that it was difficult for the watertight material to enter the gaps between the strands. Furthermore, since the watertight material is supplied in the form of a tape and heated to permeate it, it has been difficult to increase the working line speed.

The present invention has been made based on the above-mentioned circumstances, and provides a watertight electric wire manufacturing method that eliminates the above-mentioned conventional drawbacks.

The invention will be explained in detail below with reference to the drawings. In front of the first twisting machine 12 that twists, for example, six strands around the center strand 10 to form seven strands 11 that become the wire base, there is a first twisting machine 12 that coats the center strand with a watertight material. An extruder 13 is provided, and a steam heating die 14 is provided at the twisting opening of the first twisting machine 12. In addition, in front of the second twisting machine 16 that twists 12 strands of wire on the 7-strand twist 11 to form the electric wire 15, there is a 7-strand twister 16.
a second extruder 1 for coating the strands 11 with a watertight material;
7 is provided, and a steam heating die 1 is installed at the twist opening.
8 is provided.

In the present invention, the central strand is coated with a watertight material, the strands are twisted around it, and at the same time as the twisting, seven strands are heated using a steam heating die to spread the watertight material sufficiently between the strands. There is. In addition, the seven strands are covered with a watertight material and the strands are twisted around it.
It is heated at the same time as it is twisted to spread the watertight material sufficiently between the strands.

As described above, in the present invention, the watertight material is supplied in a molten state and is not processed once into a tape shape and supplied as in the conventional method, so that the cost increase due to tape formation can be avoided. In addition, since an appropriate amount can be supplied using an extruder, there is no loss of watertight material. Moreover, no unevenness is caused on the surface of the electric wire due to adhesion of the watertight material. Furthermore, since no heating is performed with a gas burner, there is no risk of softening of the hard wire, decrease in tensile strength, or discoloration. Further, since the watertight material is supplied in a molten state, it can easily enter between the strands of wire, and the working wire speed can be increased.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a conventional manufacturing method, and FIG. 2 is a schematic diagram of an embodiment of the present invention. 10... Center strand, 11... 7 twists, 12,
16... twisting machine, 13, 17... extruder, 14,
18...Steam heating die, 5...Electric wire.

Claims (1)

[Claims] 1. A watertight material is extruded and coated on the central strand before the first twisting machine which twists a plurality of strands around the central strand to form the base of the electric wire, and the first twisting machine A watertight material is extruded and coated on the electric wire base before a second twisting machine that heats the electric wire base with a steam heating die at the twisting opening and twists a plurality of strands on the electric wire base to form an electric wire, A watertight electric wire manufacturing method characterized in that the electric wire is heated by a steam heating die at the twisting opening of the second twisting machine.