JPH0462034A - Method for forming laminating tape and die used therefor - Google Patents

Abstract

PURPOSE:To make it possible to easily and accurately carry out the tubular forming of laminating tape by a method wherein the draw forming with a forming die is carried out by circular line contacts, which consist of a plurality of steps arranged along the running direction and the diameter of which is gradually reduced. CONSTITUTION:First of all, a forming die consists of a plurality of truncated conical tubes 31, 32..., which are nested together. Inner facial small diameter parts 3a,... of tubes 31... are inclined curved surfaces, the diameter of each of which gradually expands out wards. Laminating tape sheath type cable is produced by setting the die 3 so as to direct its large diameter parts to upstream side during the tubular forming process of laminating tape. At this time, in the die 3, the laminating tape comes into circular contacts with die lands, since the small diameter parts of respective tubes 31... expand outwards. At the same time, the laminating tape is smoothly and gradually drawn into tubular form without developing the standing-out of overlapped parts and erosion.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for forming a laminate tape of a laminate sheathed cable into a cylindrical shape, and a die used therein.

[Prior art and its problems] Laminated sheath type cables are made by forming a laminate tape made of aluminum foil and polyethylene film (PE) on the outer periphery of the cable core into a cylindrical shape with the PE layer on the outside. The overlapping parts are heat-sealed, and an outer cover made of high-density polyethylene (HDPE) is extruded directly above it, and the inside of the outer cover and the PE of the laminate tape are bonded.
The layers are fused together using heat and pressure during extrusion molding of the outer cover.

The process of attaching the laminate tape to the cable core, that is, the method of forming the laminate tape into a cylindrical shape, first involves a laminate tape forming roll 1, a forming gutter 2, a forming die 3, as shown in FIGS. 1 and 2. A heating blower 4 and a press roller 5 are provided in this order in the running direction of the cable core a.

As shown in FIG. 5, the forming roll 1 includes a drum-shaped male roll 1a and a drum-shaped male roll 1b having axes perpendicular to the running direction.
and an uneven surface 1a of both rolls 1a and 1b.
When the laminate tape b is fed into the grooves 1a' and 1b', the laminate tape b is formed into a dish shape in the width direction by pressure contact between the uneven surfaces 1a' and 1b', and the laminate tape b runs in the forming gutter 2. The laminate tape b is pressed against the cable core a, and the laminate tape b is pressed against the cable core a by a heating blower 4. The overlapped portions of b are heated and pressed together using a releasable pressing roller 5 to be thermally fused (seamed).

In this molding process, the finish of the cylindrical molding of the laminate tape b is greatly influenced by the inner surface shape of the die 3, that is, the land shape and its arrangement.

For this reason, the present inventors have hitherto determined that the introduction angle of the die 3,
Various studies have been conducted to mold the land into a desired cylindrical shape by changing the length of the land, exit angle, etc. but,
In this way of thinking, - the stretched cylindrical laminate tape b rebounds due to its elasticity and cannot be finished in a cylindrical shape with a good outer diameter (shape), especially in order to obtain a product without floating seams. It took a lot of effort.

In view of the above points, an object of the present invention is to enable easy and accurate cylindrical molding of a laminate tape.

[Means to solve the problem]

In order to solve the above problems, in the forming method according to the present invention, in the above-mentioned method, the drawing by the forming die is made into circular line contact around the cable core, and the line contact is It was designed to have multiple stages along the direction, and to gradually reduce its diameter.

In addition, the above-mentioned forming die used in the forming method is composed of a plurality of truncated conical tubes, and the small diameter portion of the land is an inclined surface that gradually increases in diameter toward the outside. are fitted on the same shaft with the land large diameter part on the upstream side in the running direction, and the land small diameter part of each truncated conical cylinder has a configuration in which the diameter becomes smaller in turn toward the downstream side in the running direction. be.

[Effect]

In the present invention configured as described above, the laminate tape is formed into a cylinder in the same manner as in the past, but when drawing by the die, the laminate tape is sequentially formed by circular line contact in multiple stages. This prevents the repulsion due to its elasticity. Therefore, floating of the cylindrical overlapping portion of the laminated tape (layering of both sides of the tape at the overlapping portion) does not occur.

Furthermore, since the squeezing action is based on line contact, there is little contact resistance with the laminate tape, and local sagging (wrinkles) of the laminate tape does not occur.

[Example] First, the forming die 3 will be explained. As shown in FIG. 3, a plurality of truncated conical cylinders 3. ．． 3. ...... are fitted together, and this f13. . . . is made of mechanical structural steel (S 35 C") and has hard chrome plating on the inside. Also, as shown in Fig. 4,
The inner small diameter portion 3a+ of the cylinder 31 has an inclined curved surface that gradually expands in diameter toward the outside.

Thirty-five cylinders 31 having this configuration were manufactured, with the dimensions of the small diameter portion, A, B, and C shown in Table 1 below.

Table 1 Unit, nφ The plurality of cylinders 3. . . . Inside, a tube 3 having appropriate dimensions A, B, and C according to the diameter of the cable core a.
Select an appropriate number of . . . and fit them on the same axis as shown in FIG.・・・
The small diameter portions 3a+... of... constituted the die 3 so that the diameter gradually becomes smaller toward the left in the figure.

As shown in FIGS. 1 and 2, this die 3 is set in the cylindrical molding process of the laminate tape b with its large diameter part facing upstream, as in the conventional method, to form a laminate sheath mold. Manufactured cables. At this time, dice 3
, the small diameter portion of each portion 3I... is expanded outward, so the laminated tape and the die land are in circular line contact, and each small diameter portion 3a+
. . . was gradually reduced in diameter, it was smoothly and gradually constricted into a cylindrical shape as shown by the chain line in Fig. 3, and there was no lifting of the overlapped portion and no sagging occurred.

(Effects of the Invention) The present invention is constructed as described above, prevents the repulsion of the laminate tape in the die, prevents floating of the overlapped portion, and prevents partial sagging, so that the laminate tape is prevented from floating. The tape is easily and reliably formed into a cylinder and placed over the cable core with high finishing accuracy.

[Brief explanation of the drawing]

FIG. 1 is a schematic front view of an embodiment of the method for forming a laminated tape according to the present invention, FIG. 2 is a plan view of the same embodiment, FIG. 3 is an enlarged sectional view of the die in FIG. The figure is an enlarged sectional view of the truncated conical tube shown in FIG. 3, and FIG. 5 is a right side view of the forming roll shown in FIG. 1. 1... Laminating tape forming roll, 2...
... Molding machine, 3... Molding die,
3. 3. ......Truncated conical tube, 3a+, 3az...Small diameter part, 4...
Heating roller, 5... Presser roller, a...
...Cable core, b... Laminate tape.

Claims (2)

[Claims] (1) The cable core is run in a straight line, and along the running path, a forming roll, a forming gutter, a forming die, a heating means, and a pressing roll are arranged in order, and the forming roll, forming gutter, and forming die are arranged in order. A laminate tape is guided, and the laminate tape is formed into a cylindrical shape so as to wrap around the cable core, and the overlapped portion of the cylindrical laminate is heated, and then the laminate tape is pressed by the pressure roll and heat welded. In the forming method, the drawing by the forming die is performed in a circular line contact around the cable core, and the line contact is made in multiple stages along the running direction, and the diameter is gradually reduced. A method for forming laminated tape characterized by: (2) The above molding die used in the method for molding a laminate tape according to claim (1), comprising a plurality of truncated conical tubes, the small diameter portion of the land being sloped so that the diameter gradually expands toward the outside. The truncated conical tubes are fitted together on the same axis with the land large diameter portion facing upstream in the running direction, and the land small diameter portion of each truncated conical tube facing downstream in the running direction. A molding die characterized by having diameters that gradually become smaller.