JPH0756524B2 - Optical cable and manufacturing method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Outline of the Invention] An optical fiber bundle in which a plurality of optical fibers are concentrated and roughly wound with colored threads, strings or tapes at a winding tension higher than the supply tension of the optical fibers. An optical cable and a manufacturing method capable of protecting an optical fiber from abnormal tension and easily increasing the number of optical fiber cores that can be identified in the same pipe by a structure in which a plurality of LAP tapes are assembled and housed in a pipe.

[Industrial application field]

The present invention relates to a multi-fiber optical cable or optical unit and a method for manufacturing the same, and more particularly to a structure of an optical cable or an optical unit for preventing abnormal tension applied to the optical fiber and facilitating identification of the optical fiber core wires in the same pipe and a method for manufacturing the same. It is a thing.

[Conventional technology]

As an example of an optical cable or optical unit in which a plurality of optical fibers are housed in a pipe, a structure in which about 10 fibers are housed in a plastic pipe formed by tube extrusion is known (for example, U.S. Pat. No. 4,153,33).
No. 2 bulletin). FIG. 6 shows an outline of the cross-sectional structure of this type of 10-core accommodating loose tube core wire. Reference numeral 2 is an optical fiber, and 3 is a thermoplastic resin pipe. In the conventional structure, the optical fiber 2 is generally colored differently in order to identify the optical fiber.

Further, in the conventional manufacturing method, in order to improve the identification of each optical fiber 2 as shown in FIG. 7, the outer periphery of the optical fiber 2 is roughly wound with a short pitch so as not to adversely affect the optical fiber 2. Rough winding is performed with low tension.

[Problems to be solved by the invention]

The optical cable having the conventional structure has a limitation that all the optical fibers are colored for identifying the optical fiber, and thus there is a limitation that the number of fibers cannot be increased. Also, since the ordinary optical cable shown in FIG. 6 does not have a tensile strength structure because of the loose tube core structure, it is difficult to control the tension at the time of manufacturing, and excessive tension may be applied to the optical fiber. There is a problem that extremely high technology is required to stably manufacture a long optical unit of this kind of structure. Further, as shown in FIG. 7, in the case of a structure in which a plurality of optical fibers are concentrated and roughly wound, in order to perform high-speed manufacturing, the coarse winding head 5 should be tensioned at a low tension in order to perform high-speed production. It is necessary to rotate at high speed, which is difficult in terms of equipment. Further, since the optical fiber bundle in which the optical fibers are concentrated does not have a tension member, there is a problem that it is necessary to pay attention to the tension relationship so as not to apply an excessive tension to the optical fiber.

[Means for solving problems]

In order to solve the conventional problems, the present invention coarsely winds an optical fiber bundle with a thread, a string or a tape with a winding tension higher than the supply tension of the optical fiber, and identifies the coarsely wound thread, the string or the tape. It features a colored structure.

[Work]

The present invention protects the optical fiber from abnormal tension by making the coarse winding tension applied to the optical fiber bundle larger than the supply tension of the optical fiber at the time of manufacturing, and coloring the coarse winding allows the inside of the same pipe to be protected. The number of identifiable optical fibers can be easily increased. Embodiments will be described below with reference to the drawings.

〔Example〕

FIG. 1 shows an outline of the cross-sectional structure of a 24-fiber optical cable according to an embodiment of the present invention. In a pipe (hereinafter referred to as a pipe) 3 made of a thermoplastic resin such as nylon, polypropylene or polyethylene, an optical fiber 2 is provided around a tensile strength member 4.
This is an example of forming a 24-fiber optical cable by accommodating four 6-fiber optical fiber bundles 1 each having a longitudinal core. As shown in the cross-sectional view of one embodiment in FIG. 3, the pipe 3 is made of, for example, a metal or plastic, or a composite of metal and plastic is vertically attached to the outer periphery of a LAP tape 6 formed into a circular shape and a thermoplastic resin A structure in which the pipe 3 is covered may be used. The edge of the LAP tape 6 may be abutted as shown in FIG. 3, or may have a structure having an overlapping portion formed by vertically attaching it in a circular shape.
The former butt structure is preferable in terms of mechanical strength.

The optical fiber bundle stored in the optical cable shown in FIG.
As shown in FIG. 2, it has a structure in which it is twisted around the coarse winding yarn 5, and this is because the tension of the coarse winding yarn 5 is made stronger than the tension of the optical fiber bundle. It goes without saying that the coarse thread used is colored for identification. According to the present embodiment, for example, in the configuration shown in FIG. 1, the all-optical fiber can be specified only by applying 6 colors as the optical fiber and 4 colors as the coarse winding thread, and it is possible to increase the number of cores with a small number of colors. . Furthermore, in the case of a large-capacity optical cable composed of a plurality of pipes, the number of cores can be easily increased by coloring the pipes.

Further, since the optical fiber bundle of the present invention is configured such that the optical fiber is wound around the coarse winding as shown in FIG. 2, a material having a characteristic of high Young's modulus such as Kevlar ( If you use (registered trademark), econole fiber, etc., the coarse thread will also have the function of tensile strength fiber,
Tension-related restrictions become easier. For example, if a 1140d Kevlar (registered trademark) is used, the elongation of the optical fiber bundle can be suppressed to 0.1% or less even with a tension of 1.5 kg. The production of the present optical fiber bundle can be realized by making the tension of the coarse winding yarn larger than the supply tension of the optical fiber, and the basic production equipment is the same as the conventional production equipment of the optical fiber bundle shown in FIG. Since the tension relationship does not require relatively strictness, it is easy in terms of equipment.

Since the structure of the optical cable according to the present invention is a structure in which the optical fiber is wound around the coarse winding system, it is strong against bending and it is not necessary to twist the optical fiber itself. Further, by controlling the tension of the coarse winding yarn and the supply tension of the optical fiber, the optical fiber can be easily slackened. For example, add about 1.1 kg of tension to the 1140d Kevlar® (extension 01%), and
When 6 optical fibers with a supply tension of 0 g (extension 0.05%, glass fiber 125 μmφ) are roughly wound, a slack of about 0.05% is attached. However, it is necessary to consider shrinkage of the outer pipe in practice.

The structure in which the optical fiber according to the present invention is combined with the tensile strength member also improves workability in construction.

FIG. 4 shows a cross-sectional structure of a 5-fiber optical fiber bundle accommodating 10-fiber optical cable according to an embodiment of the present invention. Collect 5 optical fibers,
This is a structure in which two optical fiber bundles 7 that are roughly wound with 1140d Kevlar (registered trademark), LAP tapes are formed into a circular shape, but are abutted, and then housed in a thermoplastic resin pipe 3 covered with a plastic pipe.

FIG. 5 shows an outline of the manufacturing process. 5 optical fibers 2
Supplied from the optical fiber supply bobbin 8 and the concentrating dice 9
The rough winding supply bobbin 10
Cobra 5 from the coarse winding system Coarsely wound by
Gather 5 fiber optic fiber 7 with 2 set dice 12,
Inside the LAP tape 6 that is molded and supplied from the loop supply drum 13.
And then PE-coated with a crosshead 14 for extrusion.
The LAP pipe cable 15 is produced. Kevlar of coarse winding thread 5
(Registered trademark) is one that is colored blue and yellow in this embodiment.
used. The manufacturing condition is that the supply tension of the optical fiber 2 is 50.
g, the winding tension of the Kevlar (registered trademark) of the coarse winding system 5 is 500 g,
The coarse winding pitch was 100 mm. During manufacturing, obstacles during manufacturing
There was no particular harm, and the production was successful.

For comparison, in the same manufacturing process as in FIG. 5, when manufacturing was performed with a winding tension of 50 g for roughly winding Kevlar (registered trademark) as a coarse winding yarn, one fiber was broken during the manufacturing. There was a failure to do so. The cause seems to be the abnormal tension applied to the optical fiber. No particular difference was found in the mechanical properties of the optical cables obtained when the winding tension of the coarse winding was 500 g and 50 g.

Further, according to the present invention, as shown in FIG. 5, the optical cable having the structure of FIG. 4 can be manufactured in one step. It is possible to realize a low-cost optical cable that can be realized.

Although the embodiment described above has described the optical cable,
It is obvious that the present invention is similarly applied to the optical fiber assembly type optical unit having the same structure, which is one aspect of the present invention.

〔The invention's effect〕

As described above, the present invention is very effective in protecting the optical fiber from the abnormal tension under the simple manufacturing condition that the winding tension of the coarse winding is made higher than the supply tension of the optical fiber. Furthermore, by coloring the winding roughly, it is possible to easily increase the number of identifiable optical fiber cores in the same pipe, which is also effective in increasing the number of cores.

[Brief description of drawings]

FIG. 1 is a cross-sectional structural view of a 24-fiber optical cable according to an embodiment of the present invention,
FIG. 2 is a block diagram of an optical fiber bundle according to the present invention, FIG. 3 is a sectional view of an embodiment of an optical fiber bundle storing pipe according to the present invention, and FIG. 4 is a five-fiber optical fiber bundle storing 10 of an embodiment of the present invention.
FIG. 5 is a cross-sectional structural view of the optical fiber cable, FIG. 5 is a schematic view of the steps of a method for manufacturing a 10-fiber optical fiber cable containing a 5-fiber fiber bundle according to the present invention,
FIG. 6 is a cross-sectional structural view of a conventional 10-fiber storage loose tube core wire, and FIG. 7 is a configuration diagram of a conventional optical fiber bundle. 1 ... 6-fiber optical fiber bundle, 2 ... Optical fiber, 3 ... Thermoplastic resin pipe, 4 ... Tensile member, 5 ... Coarse winding thread, 6
…… LAP tape, 7 …… 5-fiber optical fiber bundle, 8 …… Optical fiber supply bobbin, 9 …… Concentration die, 10 …… Rough winding thread supply bobbin, 11 …… Rough winding head, 12 …… Assembling die, 13 …… LAP tape supply drum, 14 …… Extrusion crosshead, 15 …… LAP pipe cable

 ─────────────────────────────────────────────────── ─── Continuation of front page (56) Reference JP-A-55-124908 (JP, A) JP-A-57-111501 (JP, A) JP-A-58-5703 (JP, A) JP-A-60- 57305 (JP, A) Actual Open 57-142704 (JP, U) Actual Open 59-161105 (JP, U) Actual Open 59-82210 (JP, U)

Claims (5)

[Claims] 1. An optical cable having a structure in which an optical fiber bundle of a plurality of optical fibers is housed in a pipe, wherein the optical fiber bundle is roughly wound with a thread, a string or a tape, and the winding tension of the rough winding is An optical cable characterized by having a structure larger than the supply tension of the optical fiber. 2. The optical cable according to claim 1, wherein the optical fiber bundle has a non-twisted structure. 3. The optical cable according to claim 1, wherein the coarsely wound thread, cord or tape is colored for identification. 4. The optical cable according to claim 1, wherein the pipe is colored for identification. 5. A method of manufacturing an optical cable in which a plurality of optical fibers are concentrated and housed in a pipe, wherein the plurality of optical fibers are concentrated to form an optical fiber bundle, and the optical fiber bundle is formed by using a thread, a string or a tape. Coarse winding is performed with a winding tension higher than the fiber supply tension, a plurality of the roughly wound optical fiber bundles are collected, the collected optical fiber bundles are inserted into a LAP tape, and the outer circumference of the LAP tape is covered. A method for manufacturing an optical cable, which comprises the step of coating