JPH0643944Y2 - Optical composite overhead ground wire - Google Patents

Description

[Detailed Description of the Invention] [Outline of the Invention] An optical fiber unit, which is an assembly of a plurality of optical fibers, is housed in the groove of the grooved Al spacer, and the optical fiber unit is installed on the outer periphery of the grooved Al spacer.
An optical composite overhead ground wire with a structure in which a sheath is applied with an Al pipe and Al covered steel wires are gathered around the sheath, and the optical fiber unit has an outer diameter of 0.6 mm coated only with silicone resin.
The following optical fiber and tension member are twisted together to form a composite body, and a heat-resistant resin tape having a melting point of 200 ° C or higher is wound around the periphery of the composite body, so that the outer diameter of the cable is small, In addition, it is an optical composite overhead ground wire that can be easily taken out without damaging the optical fiber at the time of connection, the coating process can be omitted, and the connection and measurement work can be facilitated and productivity can be improved.

[Industrial field of application] The present invention stores an optical fiber unit in which a plurality of optical fibers are assembled in the groove of an Al spacer with grooves, and sheathes an Al pipe on the outer periphery, and an Al covered steel wire on the outer periphery of the sheath. The present invention relates to an integrated optical composite ground wire, and particularly to a structure of an optical fiber unit which has a small outer diameter and is easy to connect and measure and has high productivity.

[Conventional technology]

Fig. 3 shows the cross-sectional structure of this type of optical composite overhead ground wire. Four
Is an optical fiber unit housed in the groove 5 of the grooved Al spacer 6, 7 is an Al pipe covering the outer periphery of the grooved Al spacer 6, and 8 is an Al covered steel wire gathered on the outer periphery of the Al pipe 7. .

FIGS. 4a and 4b show a cross-sectional structure of an example of a conventional optical fiber unit, and FIGS. 4a and 4b show examples of 3 cores and 6 cores, respectively. The example of FIGS. 4a and b is
This is a structure in which the optical fibers 1 coated with silicon are assembled into three cores and six cores, and a heat resistant resin 9 is extrusion-coated on the outer periphery thereof. Hereinafter, it is referred to as Prior Art 1. 2 indicates a tension member.

FIGS. 5A and 5B show a sectional structure of another example of the conventional optical fiber unit, which is an example of 3 cores and 6 cores as in the example of FIGS. 4A and 4B. The example of FIGS. 5A and 5B has a structure in which, when the optical fibers 1 are assembled, silicon 10 is filled between the optical fibers 1 and integrated, and the outer periphery of the optical fibers 1 is extrusion-coated with the heat resistant resin 9. Hereinafter, it is referred to as Prior Art 2.

[Problems to be solved by the invention]

The optical composite overhead ground wire that houses the optical fiber unit having the structure of the conventional technique 1 has an outer shape of the optical fiber unit, and the outer shape of the optical fiber unit remains uneven even after the optical fiber assembly is coated with a heat-resistant resin. Therefore, it is difficult to adjust the height of the blade that tears the coating when removing the coating during connection or measurement, the optical fiber is easily scratched, and the heat-resistant resin coating is difficult to remove.

Further, in the optical composite overhead ground wire that stores the optical fiber unit having the structure of the conventional technique 2, it is necessary to fill the gap between the optical fibers with silicon when the optical fiber unit is formed, which inevitably raises the price. Further, since the optical fibers are fixed to each other with silicon, it is difficult to separate the optical fibers at the time of connection or measurement, and the optical fibers are easily damaged at the time of separation, which causes a problem in connection and measurement work together with the conventional technique 1.

In addition, the optical fiber coated only with silicone resin is weak in strength and sensitive to lateral pressure.When the tape is wound directly on the optical fiber, the optical fiber is slightly bent due to the step created at the edge of the tape overlapping part, and the optical fiber is slightly bent. There were also problems such as deterioration of loss characteristics.

[Means for solving problems]

In order to solve the conventional problems, the present invention has a thin heat-resistant resin tape having a melting point of 200 ° C. or more and 50 μm or less wound around the outer periphery of a composite body in which an optical fiber unit is twisted and assembled with an optical fiber and a tension member. It is characterized by having a structure.

[Action]

Since the structure of the optical fiber unit according to the present invention is a twisted composite of the optical fiber and the tension member, it can withstand the tension during winding of the heat resistant resin tape and the heat resistant resin tape is sufficiently thin. Therefore, it is possible to reduce the slight bending of the fiber due to the tape edge, obtain good optical loss characteristics, and because it is a heat-resistant resin tape winding type,
Can be easily separated without damaging the optical fiber when connecting or measuring. Embodiments will be described below with reference to the drawings.

〔Example〕

1 (a) and 1 (b) show a sectional structure of an embodiment of an optical fiber unit according to the present invention. FIGS. 1a and 1b are examples of 6-core and 3-core, respectively, 1 is an optical fiber, 2 is a tension member made of, for example, steel wire, fiber reinforced plastic (FRP), kepra, and 3 is a heat-resistant resin tape. Indicates.

FIG. 2 is a view for explaining the structure of an embodiment of a 6-fiber optical fiber unit according to the present invention. When the optical fiber unit is assembled, not only the optical fiber 1 but also the tension member 2 is always twisted and assembled together as a unit to form a composite, so that when the outer periphery is wound with the heat resistant resin tape 3, In order to ensure stable and reliable winding, the heat-resistant resin tape 3 has a structure that can withstand the tension during winding.

Also, the heat-resistant resin tape 3 is a sufficiently thin tape so as not to affect the transmission characteristics of the optical fiber 1, that is, to prevent an increase in transmission loss, for example, a thickness of 50 μm or less, although there are some differences depending on the material. It is preferable to wind at. Further, the heat-resistant resin tape 3 preferably has a melting point of 200 ° C. or higher because the actual use temperature of the optical composite overhead ground wire is always 100 to 150 ° C.

Next, specific examples will be described.

As a 6-fiber optical fiber unit having the structure shown in FIG.
0.4mm in diameter together with 0.4mmφ steel wire tension member
A composite structure in which 6 cores of φ optical fiber are twisted and assembled, and a polyimide tape (decomposition temperature 575 ° C) is wound around the outer periphery of the polyimide tape (decomposition temperature 575 ° C) with a thickness of 12.5 μm to have a length of 1 km. It was made.

As a result of measuring the transmission characteristics of the optical fiber unit having the above structure, no increase in transmission loss due to the winding of the polyimide tape was observed.

By coating the tension member with silicon, a cushioning effect can be brought about and further stabilization of the transmission loss can be expected.

[Effect of device]

As described above, in the optical composite overhead ground wire of the present invention, the optical fiber unit to be stored has the tape winding structure of the twisted composite of the optical fiber and the tension member. Since the optical fiber can be easily taken out without damage, connection and measurement work can be performed easily and stably, and since it is a composite structure that gathers the optical fiber and tension member together,
Since it withstands the tension caused by winding the heat-resistant resin tape at the time of assembly, it is possible to wind the assembly and the heat-resistant resin tape and omit the coating process, improving productivity and reducing the outer diameter, which is economical. Since it has advantages and the quality is sufficiently stable, it is effective when applied to multi-core optical composite overhead ground wire.

Moreover, since the heat-resistant resin tape is very thin, less than 50 μm, not only can the outer diameter of the optical fiber unit be reduced, but also the increase in transmission loss due to the slight bending of the optical fiber due to the tape edge can be suppressed. I can.

[Brief description of drawings]

1A and 1B are sectional views of an optical fiber unit according to the present invention, FIG. 2 is an explanatory view of an optical fiber unit structure according to the present invention, FIG. 3 is a sectional structure of an optical composite overhead ground wire, and FIG. Figure
a and b and FIGS. 5a and 5b are sectional structures of an example of a conventional optical fiber unit, respectively. 1 ... Optical fiber, 2 ... Tension member, 3 ... Heat-resistant resin tape, 4 ... Optical fiber unit, 5 ... Groove, 6 ... Groove
Al spacer, 7 ... Al pipe, 8 ... Al covered steel wire, 9 ... Heat resistant resin, 10 ... Silicon

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References Japanese Patent Laid-Open No. 50-131537 (JP, A) Actual Opening 59-151206 (JP, U) Actual Opening 60-48620 (JP, U) Actual Opening 60- 74411 (JP, U)

Claims (2)

[Scope of utility model registration request] 1. An optical fiber unit (4) having a plurality of optical fibers (1) assembled in a groove (5) of a grooved Al spacer (6), the outer periphery of the grooved Al spacer (6). In an optical composite overhead ground wire having a structure in which a sheath made of an Al pipe (7) is applied to the outer periphery of the sheath, and an Al-covered steel wire (8) is gathered on the outer periphery of the sheath, the optical fiber unit (4) is coated only with a silicone resin. A heat-resistant resin tape (3) having a melting point of 200 ° C or more and a thickness of 50 μm or less was wound directly on a composite body in which an optical fiber (1) having an outer diameter of 0.6 mm or less and a tension member (2) were twisted and assembled. Optical composite overhead ground wire characterized by its structure. 2. The optical composite overhead ground wire according to claim 1, wherein the tension member (2) is coated with silicon.