JPH05250943A - Manufacture of circularity type sheath cable - Google Patents

Abstract

PURPOSE:To fill sheath material to groove parts of a twisted cable core sufficiently, achieve a smooth outer appearance, and finish it to be circular securely if a cable size or the sheath material is varied by providing a pressure cooling device at an outlet of a die. CONSTITUTION:Sheath material 18 heat fused by an extruder B is guided to a crosshead C installed at a forward end of the extruder B, a twisted cable core 17 comprising plural insulation core wires twisted with each other is guided to a nipple assembled in a head C, and the material 18 is moulded in the die. In this case, a pressure cooling device main body A with which it can be cooled under a pressurizing atmosphere is provided at an exit of the die, and the fused resin-coated cable core 17 obtained by moulding in the die is cooled and solidified under pressurization. Its form can thus be fixed while maintaining a smooth condition, so if the size of the cable core 17 or the material 18 is varied, the material 18 can be filled to groove parts of the cable core 17 sufficiently, achieving a smooth apperance and finishing it to be circular.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improved method for manufacturing a solid type sheath cable.

[0002]

2. Description of the Related Art A full-length sheath cable having a sheath material filled with a sheath material between twisted cable cores is a sheath material formed by twisting two or more insulating core wires directly above the twisted cable core. When the extrusion coating method is used, the extrusion speed and the take-up speed are adjusted to be higher or almost the same as the extrusion speed so that the troughs of the twisted cable cores are sufficiently filled with the material. When full extrusion molding is performed, the twist of the insulated core wire of the twisted cable core appears on the sheath. In order to prevent this twist from appearing, extrusion coating of the sheath material is performed by a pipe extrusion method, and the take-up speed of the twisted cable core is made faster than the extrusion speed of the sheath material. That is, it may be considered that the sheath material is drawn off, but this does not sufficiently fill the valley portion of the twisted cable wire core with the sheath material.

Therefore, when a sheath is extruded directly on a twisted cable core formed by twisting two or more insulating cores, the twist of the twisted cable core is formed on the sheath by full extrusion molding. Although it appears in Fig. 2, pre-forming is performed so that the trough of the twisted cable core is sufficiently filled with the sheath material, and then the sheath material is pipe-extruded on the cable sheath in which the twist is obtained in It is applied so that the above-mentioned twists are eliminated and it is finished in a round shape. It is done through such a process.

However, in the above method, since the process comprises two steps, the productivity becomes extremely poor. In order to solve this problem, a method of filling the valley portion of the twisted cable wire core with a sheath material in one step and finishing the appearance smooth is shown in Japanese Utility Model Publication No. 58-510 and Japanese Utility Model Publication No. 3-14744. As described above, the sheath extrusion molding die (die,
Various methods of changing the shape of the nipple have been proposed, but this method requires a great deal of work because it is necessary to change the details of the shape of the die and nipple by trial and error whenever the cable size or sheath material changes. Further, in terms of the effect, there is a drawback that it is difficult to sufficiently satisfy the quality (the valley portion of the twisted cable wire core is completely filled with the sheath material and the appearance is finished smoothly).

[0005]

DISCLOSURE OF INVENTION Problems to be Solved by the Invention As a result of intensive studies in view of the present situation, the present invention produces a solid type sheath cable in which a sheath is extruded directly above a twisted cable core formed by twisting a plurality of insulating core wires. In this method, various sheath materials are extruded and coated directly on top of various twisted cable cores of different sizes in which multiple insulated wire cores are twisted, but the troughs of the twisted cable cores are sufficiently filled with the sheath material. The present invention has found a manufacturing method capable of achieving a smooth appearance, a round finish, and a low cost (one step) to solve the conventional quality problems.

[0006]

That is, the present invention relates to a method for manufacturing a solid type sheath cable in which a sheath material is fully extrusion-molded directly above a twisted cable wire core in which a plurality of insulating core wires are twisted together. It is characterized in that the sheath immediately above the wire core is formed by the solid extrusion molding method, and the obtained melted resin-coated twisted cable wire core is cooled and solidified in a pressurized cooling atmosphere.

In the present invention, a sheath material is fully extruded directly above a twisted cable wire core formed by twisting a plurality of insulated core wires, and the obtained molten resin-coated twisted cable wire core is cooled in a pressurized cooling atmosphere. Even if the cable size and the sheath material are changed by one step of solidification, not only can the sheath material be sufficiently filled in the troughs of the twisted cable wire core, but also the appearance can be made smooth and surely rounded. Is estimated to be approximately as follows.

FIG. 1 shows one embodiment of the method of the present invention, in which the sheath material heat-melted by the extruder (B) is
Guided by the crosshead (C) attached to the tip of the extruder,
On the other hand, a twisted cable wire core (17) formed by twisting a plurality of insulated core wires is introduced into a nipple incorporated in the crosshead (C) and a sheath material is molded (squeezed) by a die.
Adjust the extrusion speed of the sheath material and the take-up speed of the twisted cable core so that the trough of the twisted cable core is sufficiently filled with the material so that the extrusion speed of the sheath material is faster or almost the same. Perform solid sheath extrusion molding.

In such a full-sheath extrusion molding, as a result of closely observing the phenomenon in which the twists of the twisted cable core appear on the sheath, the sheath layer immediately after being molded by the die has a rounded atmosphere. The twists of the twisted cable core will appear on the sheath as it is exposed to the surface. The extent of this is the size of the gap originally present in the valley of the twisted cable core, that is, the twisted insulation. The larger the cross-sectional area of the valley between the insulated core wires inside the circumscribed circle of the core wire, the more noticeable it is.Therefore, the twists appearing on the sheath are extruded on the valleys and peaks of the twisted cable core. It is assumed that this is caused by a large difference in the resin pressure of the sheathed material.

On the other hand, in the method of the present invention, a device capable of cooling in a pressure atmosphere is provided at the die outlet, and the molten resin-coated twisted cable core obtained by molding with a die is cooled and solidified under pressure. Therefore, it is estimated that it is possible to solidify the shape while maintaining a smooth state without causing a difference in the release of the resin pressure of the sheath material between the crests and the troughs of the twisted cable core. As a result, the size of the twisted cable core is not only changed, but even if it is combined with a sheath material having various melting characteristics, by setting appropriate pressurizing conditions, the sheath at the trough of the twisted cable core is set. It is a material that can be fully filled with a material and that has a smooth and round appearance.

[0011] In the present invention method, an appropriate pressure conditions during cooling is applied pressure is less than 0.2 kg / cm ² or more 5 kg / cm ^2. The reason for this is that if it is less than 0.2 kg / cm ² , the twists of the twisted cable wire core will appear although they are slight in appearance. Also, if the pressure exceeds 5.0 kg / cm ² , the twisted cable wire core and the sheath material will adhere to each other. Further, the method of the present invention is particularly remarkable effect is exhibited when the cross-sectional area of the valley between the insulation core wire inside the circumscribed circle of Yoawase cable wire core is preferably from 10 mm ² is 20 mm ² or more.

Next, as a concrete method for cooling and solidifying under a pressure atmosphere, the extruder (B) side of the pressure cooling apparatus main body (A) can be directly connected to the crosshead (C). Structure [(11) For example, a slide tube is provided to make the crosshead (C) and the cooling tank body (B) completely sealed], and a packing with a hole at the rear that is approximately the same as the outer diameter of the cable Provide (12) as a seal. Cool the shower ring (1
3), and to discharge to the outside of the cooling device main body (B), install a piston valve (14) while adjusting the water level, thereby blocking the pressure in the cooling tank from leaking to the outside of the main body (B). To do. Pressurization is performed by nitrogen gas and air from a cylinder (15) or a compressor, and the pressure is adjusted by a valve (16).

In the present invention, the twisted cable core means two insulated core wires obtained by coating a single wire or a twisted conductor with a plastic or rubber material such as polyvinyl chloride, polyethylene or ethylene-propylene copolymer. It means a twisted product.

The term "full extrusion molding of the sheath material" as used in the present invention means that the diameter of the die and the finished outer diameter of the sheath are almost equal when the sheath layer formed on the twisted cable wire core is extrusion molded. Is a method of adjusting the extrusion speed and the take-up speed so that the sheath material is sufficiently filled in the valley portion of the twisted cable wire core.

The sheath material is not particularly limited, and all commonly used plastics and rubber materials such as vinyl chloride resin, polyolefin resin, chloroprene rubber and polyurethane can be applied.

[0016]

【Example】

[Comparative Example 1] Insulation in which an insulating layer made of cross-linked polyethylene having a thickness of 0.5 mm is provided on a conductor having a cross-sectional area of 0.5 mm ² which is formed by concentrating 7/38 / 0.05 mmφ Immediately above the twisted cable wire core in which two core wires are twisted together,
When extruding a solid type sheath made of polyurethane resin, guide the twisted cable wire core to a nipple with a hole diameter of 4.1 mm, and thoroughly extrude the heat-melted polyurethane resin with a die with a hole diameter of 6.5 mm to form an atmosphere. A cable for a sensor was manufactured by setting the take-up speed so that the solidified product was solidified by water cooling and the finished outer diameter was 6.5 mm.

[Comparative Example 2] In Comparative Example 1, the same procedure as in Comparative Example 1 was performed except that the take-up speed was set so that the finished outer diameter of the cable was 5.3 mm and the sheath material was pipe-extruded. A sensor cable with a structure was manufactured.

[Comparative Example 3] In Comparative Example 2, except that a pressure cooling device was attached to the die outlet and the melt-molded product molded by the die was water-cooled under a pressure of 2.8 kg / cm ² .
The same procedure as in Comparative Example 2 was performed to manufacture a sensor cable having the same structure.

Example 1 Except that in Comparative Example 1, a pressure cooling device was attached to the die outlet, and the melt-molded product molded by the die was water-cooled under a pressure of 0.1 kg / cm ² .
The same procedure as in Comparative Example 1 was performed to manufacture a sensor cable having the same structure.

Example 2 Except that in Comparative Example 1, a pressure cooling device was attached to the die outlet, and the melt-molded product formed by the die was water-cooled under a pressure of 0.3 kg / cm ² .
The same procedure as in Comparative Example 1 was performed to manufacture a sensor cable having the same structure.

[Example 3] In Comparative Example 1, except that a pressure cooling device was attached to the die outlet and the melt-molded product formed by the die was water-cooled under a pressure of 4.0 kg / cm ² .
The same procedure as in Comparative Example 1 was performed to manufacture a sensor cable having the same structure.

Example 4 Except that in Comparative Example 1, a pressure cooling device was attached to the die outlet, and the melt-molded product molded by the die was water-cooled under a pressure of 5.7 kg / cm ² .
The same procedure as in Comparative Example 1 was performed to manufacture a sensor cable having the same structure.

[Comparative Example 4] ^On a conductor having a cross-sectional area of 8 mm ² of collective twist composed of 50 strands / 0.45 mmφ, a thickness of 1.2
When extruding a solid vinyl chloride resin sheath onto a twisted cable core, which is made by twisting three insulated core wires with an insulating layer made of vinyl chloride resin of 3 mm,
Guide the twisted cable wire core to a nipple with a hole diameter of 12.2 mm, fully extrude the heat-melted vinyl chloride resin with a die with a hole diameter of 17.5 mm, water-cool it in the air to solidify it, and finish the outer diameter. A cable for a cabtyre was manufactured by setting the take-up speed so that it would be 17.5 mm.

[Comparative Example 5] In Comparative Example 4, the same procedure as in Comparative Example 4 was performed except that the take-up speed was set so that the finished outer diameter was 16.0 mm and the sheath material was pipe-extruded. A cabtire cable having a structure was manufactured.

[Comparative Example 6] In Comparative Example 5, except that a pressure cooling device was attached to the die outlet and the melt-molded product molded by the die was water-cooled under a pressure of 3.8 kg / cm ² .
The same procedure as in Comparative Example 5 was performed to manufacture a cabtire cable having the same structure.

Example 5 Except that in Comparative Example 4, a pressure cooling device was attached to the die outlet, and the melt-molded product molded by the die was water-cooled under a pressure of 0.1 kg / cm ² .
A cable for a cabtire having the same structure was manufactured in the same manner as in Comparative Example 4.

[Example 6] In Comparative Example 4, except that a pressure cooling device was attached to the die outlet, and the melt-molded product molded by the die was water-cooled under a pressure of 0.5 kg / cm ² .
A cable for a cabtire having the same structure was manufactured in the same manner as in Comparative Example 4.

Example 7 The procedure of Comparative Example 4 was repeated except that a pressure cooling device was attached to the die outlet and the melt-molded product molded by the die was water-cooled under a pressure of 4.5 kg / cm ² .
A cable for a cabtire having the same structure was manufactured in the same manner as in Comparative Example 4.

Example 8 Except that in Comparative Example 4, a pressure cooling device was attached to the die outlet, and the melt-molded product molded by the die was water-cooled under a pressure of 5.9 kg / cm ² .
A cable for a cabtire having the same structure was manufactured in the same manner as in Comparative Example 4.

Appearance of the cables produced by the production methods of Comparative Examples 1 to 4 and Examples 1 to 8 described above, the filling property of the sheath material in the troughs of the twisted cable core, and the twisted cables as required. The degree of adhesion between the wire core and the sheath was evaluated and shown in Tables 1 and 2.

[0031]

[Table 1]

[0032]

[Table 2]

In the conventional sheath full extrusion molding of Comparative Examples 1 and 4, remarkable unevenness appears in the cable appearance, while in the pipe extrusion molding of the sheath material of Comparative Examples 2 and 5, the cable appearance is relatively round, but There is a drawback that the valley portion of the twisted cable core is not sufficiently filled with the sheath material.
Furthermore, in Comparative Examples 3 and 6 in which the melt-molded products obtained by pipe extrusion molding of the sheath materials of Comparative Examples 2 and 5 were cooled and solidified in a pressurized atmosphere, the twisted cable wire was compressed and cooled. Although the valley material of the core is sufficiently filled with the sheath material, the cable appearance becomes considerably uneven.

On the other hand, in Examples 1 to 8 in which the melt-molded products obtained by the solid extrusion molding of the sheath material of Comparative Examples 1 and 4 were cooled and solidified in a pressurized atmosphere, the valley portion of the twisted cable wire core was used. It is possible to obtain not only that the sheath material is sufficiently filled with the sheath material but also that the cable appearance has a substantially satisfactory roundness.

In particular, in Examples 2, 3 and 6 and 7, all points of the cable appearance, the material filling property of the valley portion between the twisted cable wire core and the sheath, and the adhesiveness between the twisted cable wire core and the sheath layer. It turns out that an extremely excellent product can be obtained.

[0036]

As is apparent from the above description, in the present invention, a melt-formed product obtained by fully extruding a sheath directly above a twisted cable wire core in which a plurality of insulated core wires are twisted is cooled by pressure. By cooling and solidifying in an atmosphere, even if the sheath material and cable size change, not only the trough of the twisted cable wire core is sufficiently filled with the sheath material,
It is a low cost (1
It can be realized in the process) and is extremely useful industrially.

[Brief description of drawings]

FIG. 1 is an example of a manufacturing method in which a melt-molded product obtained by fully extrusion-molding a sheath directly above a twisted cable wire core formed by twisting a plurality of insulated core wires is cooled and solidified in a pressure-cooled atmosphere. FIG.

[Explanation of symbols]

A main body of pressurizing and cooling device B extruder C molding die (crosshead) 11 structure in one embodiment of the present invention 12 packing 13 shower ring 14 piston valve 15 cylinder 16 pressure adjusting valve 17 made by twisting a plurality of insulating core wires Stranded cable core 18 Cable sheath

Claims (1)

[Claims] 1. A method for producing a solid type sheath cable in which a sheath material is fully extruded directly above a twisted cable wire core in which a plurality of insulated core wires are twisted together, and a sheath immediately above the twisted cable wire core is fully extruded. The method for producing a solid type sheath cable, which comprises forming the molten resin-coated twisted cable core and then solidifying it by cooling and solidifying it under a pressure-cooled atmosphere.