JPS5825606A - Manufacture of optical fiber cable with aluminum sheath - Google Patents

Abstract

PURPOSE:To improve the strength of an aluminum sheath by reducing the diameter of an aluminum pipe which has the steel wire inserted and a greater external diameter than final product side by using a floating plug and thus increasing the strength of the aluminum sheath, and then replacing the internal steel wire with an optical fiber cable core by drawing. CONSTITUTION:In the figure, 5 is die and 6 is a floating plug which has a throughhole 7 where a steel wire 8 runs in the center. Using the floating plug 6 adjusts the thickness of an aluminum pipe 9 as well as reduction in external diameter, obtaining the aluminum sheath which has a prescribed external diameter and prescribed thickness. One terminal of an optical fiber calbe core is connected to one terminal of the steel wire in the aluminum pipe reduced in diameter to final aluminum sheath size by an adequate method, e.g. sleeve connection, etc., and the other terminal of the steel wire is drawn out of the aluminum pipe to insert the optical fiber core into the aluminum pipe, obtaining an aluminum-sheathed optical fiber cable.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing an optical communication cable, particularly an aluminum sheathed optical fiber cable used for an overhead ground wire.

Traditionally, information transmission in power distribution systems has relied on separately installed communication cables, but in recent years, optical fiber cables (hereinafter referred to as optical cables), which are free from radio wave interference and can provide multiple lines, have been developed and put into practical use. It became so. According to this optical cable, there is no need to install a separate cable, and it is possible to encapsulate it in an electric wire or cable to form an optical fiber composite electric wire.

The optical cable used for this purpose is an aluminum sheathed optical fiber cable in which the optical fiber is protected by an aluminum sheath, as shown in FIG. 1, since the strength of the optical fiber (eg, glass fiber) is weak.

In FIG. 1, I is an optical fiber wire and 2 is an aluminum sheath. (A) Figure shows the case of single core, (0) Figure a
j: Two tension members 3 are vertically attached or twisted together on two optical fiber lines 1, and the entire circumference is covered with an aluminum sheath 2. (c) In the figure, the optical fiber wire 1 is housed in the four grooves of the grooved filament body 4, and the periphery thereof is covered with an aluminum sheath 2. Hereinafter, the core excluding the aluminum sheath 2 will be referred to as an optical fiber cable core.

In this description, an optical fiber line means a core made of one or more optical communication fibers, or a line entirely coated with synthetic resin or the like.

Conventionally, these aluminum sheathed optical cables are manufactured entirely by
Either by the so-called tape forming-welding method, in which an aluminum sheath is attached vertically around the optical fiber wire, formed into a pipe shape, and the joints are seam welded, or by the so-called tape forming-welding method, in which the optical fiber wire is fully inserted into a pre-prepared aluminum pipe. It was done by the pipe insertion method.

However, in the tape forming and welding method, hard aluminum tape has poor elongation properties, making it difficult to form a pipe-like bottom shape, and the aluminum sheath material is almost soft, so the breaking strength and
It had the disadvantage of low vibration fatigue strength.

In addition, the pipe insertion method has the disadvantage that it is not possible to manufacture long aluminum sheathed optical cables due to restrictions on the length of the cable.

The present invention was made to solve the above-mentioned drawbacks, and
After increasing the strength of the aluminum sheath by reducing the diameter of the aluminum pipe, which has an outer diameter larger than the final product size with all the steel wires inserted, using a floating plug, the inner steel wire is replaced with an optical fiber cable core. The present invention aims to provide a method for manufacturing a long aluminum sheathed optical fiber cable in which the strength of the aluminum sheath is significantly improved.

The present invention manufactures a steel wire-containing aluminum pipe in which a steel wire with an outer diameter smaller than the inner diameter of the final aluminum sheath is fully inserted into an aluminum pipe with an outer diameter larger than the outer diameter of the aluminum sheath of the final aluminum sheath optical fiber cable. After that, this is subjected to all diameter reduction processing using dies or rolls until it reaches the final aluminous size, and at least one of the diameter reduction processing is performed using a floating plug having a through hole through which the steel wire passes, and then Then, the optical fiber cable core is inserted into the aluminum pipe by connecting an optical fiber cable core to one end of the steel wire and pulling out the other end of the steel wire from the aluminum pipe. This is a method for manufacturing an aluminum sheathed fiber optic cable.

In the method of the present invention, first, an aluminum pipe containing steel wire is manufactured.

The aluminum pipe in this case is a pipe made of aluminum or an aluminum alloy, and has an outer diameter larger than the outer diameter of the aluminum sheath of the final aluminum sheathed optical fiber cable. Also, the steel wire has an outer diameter smaller than the inner diameter of the final aluminum sheath, and is made longer than the aluminum pipe in consideration of the increase in length due to the subsequent diameter reduction process of the aluminum pipe.

This aluminum pipe may be manufactured by any method such as tape forming-seam welding or extrusion, and the steel wire may be inserted into the pipe during the above-mentioned manufacturing, or it may be inserted after the pipe is manufactured. insert.

This steel wire-filled υ aluminum pipe is successively reduced in diameter using a die or roll to the size of the final aluminum sheath.

In this case, with the method using only a normal die or roll, the wall thickness of the pipe increases as the diameter decreases, the area reduction rate does not become very large, and efficient work hardening is difficult, and the aluminum sheath Since the accuracy of the inner thickness deteriorates, it is important to perform at least one diameter reduction process using a floating plug in order to prevent this.

FIG. 2 is a longitudinal sectional view showing an example of a die and a floating plug used in an embodiment of the present invention.

In the figure, 5 is a die, 6 is a floating plug, and has a through hole 7 in the center through which a steel wire 8 passes.

When all of the floating plugs 6 are used, the outer diameter of the aluminum pipe 9 is reduced and the wall thickness is adjusted at the same time. An aluminum sheath with a predetermined outer diameter and wall thickness is obtained, and the target area reduction ratio can be achieved. This enables desired work hardening and improves strength. Note that it is better to replace the floating plug 601 at a location close to the product size in terms of dimensional accuracy.

Next, one end of the 6-1 optical fiber cable core is connected to one end of the steel wire in the steel wire-filled aluminum pipe whose diameter has been reduced to the final aluminous size, by a suitable method such as a sleeve connection, and the steel wire is When the other end of the wire is pulled out of the aluminum pipe, an optical fiber core is drawn into the aluminum pipe instead of the steel wire and inserted, creating an aluminum sheathed optical fiber cable. At this time, since the inner diameter of the aluminum pipe is sufficiently larger than the outer diameter of the steel wire and optical fiber cable core, the above-mentioned pulling out and pulling in can be easily performed, and even a long cable can be used.

As described above, the method of the present invention first includes, as described above,
Since the entire aluminum pipe with steel wire is manufactured and used as a material, it is possible to make the entire length of this pipe, and it is possible to insert a long steel wire into an aluminum pipe with a large outside diameter. After that, the aluminum pipe is subjected to a diameter reduction process W= with a die or roll to the final aluminum sheath size, and the steel wire has a through hole through which the steel wire passes through at least one of the diameter reduction processes. - Since the process is carried out using a floating plug, an aluminum sheath with a predetermined outer diameter and wall thickness can be obtained by the floating plug, the target area reduction rate can be achieved, the desired aluminum sheath can be work hardened, and the strength can be improved. Finally, connect the optical fiber cable core to one end of the steel wire in the aluminum pipe,
By pulling out the entire other end of the steel wire from the aluminum pipe, the entire fiber optic cable core is inserted into the aluminum pipe, so the outer diameters of the steel wire and the fiber optic cable core are sufficiently smaller than the inner diameter of the aluminum pipe. It is very easy to replace the steel wire and the optical fiber core even in long lengths, and therefore there is an advantage that long aluminum sheathed optical cables with high strength aluminum sheaths can be easily manufactured.

In addition, the method of the present invention uses a floating plug to reduce the diameter of the aluminum sheath, so the outer diameter and wall thickness of the aluminum sheath have good accuracy, and the aluminum sheath has uniform strength over its entire length and a protective effect for the optical fiber. It has the advantage of being able to manufacture all optical cables.

[Brief explanation of the drawing]

FIGS. 1A, 1B, and 1C are cross-sectional views showing examples of aluminum sheathed optical fiber cables. FIG. 2 is a longitudinal sectional view showing an example of a die and a floating plug used in an embodiment of the method of the present invention. 1... Optical fiber wire, 2... Aluminum sheath, 3...
... Tension member, 4... Grooved linear body, 5.
...Dice, 6...Floating plug, 7...
Through hole, 8... steel wire, 9... aluminum pipe. 9-

Claims (1)

[Claims] (1) After manufacturing a steel wire-filled aluminum pipe in which a steel wire with an outer diameter smaller than the inner diameter of the final aluminum sheath is inserted into an aluminum pipe with an outer diameter larger than the outer diameter of the aluminum sheath of the final aluminum sheath optical fiber cable. This is subjected to diameter reduction processing using a die or roll to the final aluminum sheath size, and at least one of the diameter reduction processing is performed using a floating plug having a through hole through which the steel wire passes, and then the above-mentioned An aluminum sheath characterized in that the optical fiber cable core is inserted into the aluminum pipe by connecting the optical fiber cable core to one end of the steel wire and pulling out the other end of the steel wire from the aluminum pipe. Method of manufacturing optical fiber cable.