JPH0438427Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field of the Invention) The present invention relates to an improvement of a fiber optic composite overhead ground wire having an aluminum spacer.

(Technical background of the invention and its problems) In recent years, optical fiber composite overhead ground wires with a structure in which optical fibers are arranged inside aluminum pipes have been put into practical use.

As such optical fiber composite overhead ground wire,
A structure is known in which a spacer is placed inside an aluminum pipe and an optical fiber is housed in a spiral groove provided in the spacer.

That is, for example, as shown in FIG. 4, a spacer 2 provided with a plurality of spiral grooves 2a is provided in an aluminum pipe 1, and each groove 2 of this spacer 2 is
The optical fiber core 3 is accommodated in the interior a, thereby protecting the optical fiber core 3 from external forces. Note that the aluminum coated wire 4 is arranged around the circumferential surface of the aluminum pipe 1.

By the way, in order to increase the amount of information transmitted in the optical fiber composite overhead ground line having the above structure, it is sufficient to increase the number of optical fiber core wires 3, but if the number of optical fiber core wires 3 is increased, a large number of In order to provide the groove 2a, the outer diameter of the spacer 2 must be increased. Accordingly, it becomes necessary to increase the outer diameter of the aluminum pipe 1, which increases the material cost and becomes uneconomical.In addition, the outer diameter of the overhead ground wire itself also increases, so a large wind pressure is applied after installation. There is a drawback that the amount of adhesion of falling snow, etc. increases.

Further, when a large number of grooves 2a are provided in the spacer 2, the distance between the grooves 2a becomes small, so that the grooves 2a may be deformed during cutting, as shown in FIG. 5. Therefore, lateral pressure is applied to the optical fiber core wire 3, resulting in a significant increase in optical transmission loss. In addition, providing a large number of grooves 2a adjacent to each other requires a great deal of time and effort in the cutting operation, which poses a problem in terms of mass production.

Furthermore, the inside of the aluminum pipe 1 of the optical fiber composite overhead ground wire may become extremely hot due to lightning strikes or the like. Therefore, it is desirable to reliably prevent the optical fiber 3 from melting.

(Purpose of the invention) The purpose of the invention is to create an optical fiber that has a small diameter, can transmit a large amount of information, has low optical transmission loss due to lateral pressure, has a structure that can be mass-produced, and has excellent heat resistance. The purpose is to provide a composite overhead ground wire.

(Summary of the invention) The present invention is an aluminum optical tape cable in which a coating layer made of polyimide resin is provided via a buffer coat on a plurality of optical fiber cores arranged in parallel in a row and having a buffer coat made of silicone resin. It is characterized by being laminated in a groove provided in a spacer.

(Embodiments of the invention) Hereinafter, embodiments of the invention will be described in detail with reference to the drawings.

The optical fiber composite overhead ground wire according to the present invention is the first
As shown in the figure, an aluminum pipe 10 is provided. This aluminum pipe 10 is made of hard aluminum and has an outer diameter of 5.5 mm, and a rod-shaped aluminum spacer 11 is arranged inside. This aluminum spacer 11 is also made of hard aluminum, and spiral grooves 11a, 11a each having a U-shaped cross section are provided at opposing positions on its circumferential surface. This aluminum spacer 11 has a diameter of 4.6 mm, and the groove 11
A has a width of 2.2 mm and is provided with a spiral pitch of 100 to 300 mm. Optical tape cables 12, 12 are stacked in each groove 11a. As shown in FIG. 2, these optical tape cables 12 consist of six optical fiber cores 1 arranged in parallel in a row.
3, and a coating layer 14 which is extruded and coated onto these optical fiber cores 13 in a flat shape. The optical fiber core wire 13 includes a graded index type optical fiber wire, and as shown in FIG.
It has a core 13a with a diameter of 50 μm and a clad 13b with an outer diameter of 125 μm, and on the clad 13b is a primary coat 13 made of modified silicone resin.
c, and buffer coat 1 made of silicone resin.
3d is coated with an outer diameter of 300 μm. The coating layer 14 is made of polyimide resin, and the optical tape cable 12 has a heat dimension of 0.4 mm and a width dimension of
It is formed to be 1.9mm.

An overhead ground wire 15 made of an aluminum coated wire is arranged around the aluminum pipe 10, thereby forming an optical fiber composite overhead ground wire.

In this way, by stacking the optical tape cable 12 including a plurality of optical fiber cores 13 in the groove 11a of the aluminum spacer 11, a large number of optical fibers can be stacked in the aluminum pipe 10 without increasing the outer diameter of the aluminum spacer 11. The same effect can be obtained by arranging core wires. Therefore, the amount of information transmitted can be increased without increasing the outer diameter of the optical fiber composite overhead ground wire. Moreover, since it is sufficient to provide only a pair of grooves 11a having a large width dimension in the aluminum spacer 11, the cutting operation for forming the grooves 11a is extremely simple, and the grooves 11a are not deformed during the operation. Therefore, not only can an increase in optical transmission loss due to the lateral pressure of the optical tape cable 12 be prevented, but also the aluminum spacer 11 can be manufactured easily, making it possible to mass-produce optical fiber composite overhead ground wires. Furthermore, when using the optical tape cable 12 in this way, it is possible to connect it to other optical fiber composite overhead ground wire optical tape cables 12 of the same structure by using a multi-fiber connector during overhead installation. Therefore, the connection work can be done easily and in a short time, and each optical fiber core wire 13
Since they are arranged in parallel, erroneous connections can be effectively prevented. Since the optical tape cable 12 does not have a large diameter tension member,
The work of storing it in the junction box becomes extremely easy, and the junction box can be made smaller.

On the other hand, since the coating layer 14 of the optical tape cable 12 is made of polyimide resin with excellent heat resistance,
Even if the inside of the aluminum pipe 10 instantaneously rises to about 400° C. due to a lightning strike, for example, the coating layer 14 will not melt. Therefore, the optical tape cable 12
It is possible to reliably prevent each optical fiber core wire 13 from being fused. Further, since the polyimide resin is a thermosetting resin, the coating layer 14 can be continuously coated on the buffer coat 13d made of silicone resin, and therefore the optical tape cable 12
can be manufactured in a continuous process. Since the coating layer 14 made of polyimide resin is in close contact with the buffer coat 13d, the buffer coat 13d can be peeled off together with the coating layer 14, and it is also possible to attach a reinforcing heat shrink sleeve, epoxy resin, etc. Excellent adhesion and adhesion to agents. Therefore, the connection work is further simplified, and the connection portion can be reliably reinforced. Furthermore, since the coating layer 14 made of polyimide resin has a large Young's modulus, it is hardly damaged even when accommodated in the groove 11a of the aluminum spacer 11, and therefore the optical tape cable 12 is not deteriorated by moisture or the like. It can also be prevented. In addition, the coating layer 14 made of polyimide resin has advantages such as excellent fatigue and mechanical strength, chemical resistance, radiation resistance, electrical insulation, and impact resistance.

FIG. 3 shows a modification of the present invention, in which an optical tape cable 1 has a structure in which a tension member 16 made of a wire is placed in the center parallel to the optical fiber core 13.
2 is shown.

In the optical tape cable 12, a polyimide resin layer is provided on the buffer coat 13d, and a coating layer 14 made of the above-mentioned polyimide resin is provided thereon.
may be provided. Furthermore, it goes without saying that a heat insulating layer may be provided between the aluminum pipe 10 and the aluminum spacer 11 to further protect the optical tape cable 12 more reliably.

(Effects of the invention) According to the invention, the outer diameter of the aluminum spacer can be increased by laminating an optical tape cable in which a polyimide resin coating layer is provided on a plurality of optical fiber cores within the groove of an aluminum spacer. In addition, a large number of optical fibers can be incorporated into the overhead ground wire without having to do anything, and the aluminum spacer only needs to be provided with a few wide grooves. Therefore, it is possible to provide an optical fiber composite overhead ground wire that has a small diameter, can transmit a large amount of information, has low optical transmission loss, and can be mass-produced. Further, since the coating layer made of polyimide resin is provided, the optical fiber core wire of the optical tape cable does not melt even under high temperatures, and therefore, an optical fiber composite overhead ground wire with excellent heat resistance can be obtained. Since a coating layer made of polyimide resin is provided on the buffer coat made of silicone resin of the optical fiber core wire, the optical tape cable can be manufactured in a continuous process, and the buffer coat can be peeled off together with the coating layer at once. This makes the connection work extremely easy.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view of an optical fiber composite overhead ground wire according to the present invention, Fig. 2 is a cross-sectional view of an optical tape cable,
FIG. 3 is a sectional view showing a modified example of an optical tape cable, FIG. 4 is a sectional view of a conventional optical fiber composite overhead ground wire, and FIG. 5 is an enlarged sectional view of a part of FIG. 4. . DESCRIPTION OF SYMBOLS 11... Aluminum spacer, 11a... Spiral groove, 12... Optical tape cable, 13... Optical fiber core wire, 14... Covering layer.

Claims (1)

[Scope of utility model registration request] In an optical fiber composite overhead ground wire comprising an aluminum spacer provided with a spiral groove along the longitudinal direction, and an optical fiber housed in the groove, the optical fibers are arranged in parallel in a line. The optical tape cable includes a plurality of optical fiber cores having a buffer coat made of silicone resin, and a coating layer made of polyimide resin coated on these optical fiber cores via the buffer coat, and the optical fibers are laminated in the groove. Optical fiber composite overhead ground line.