JP2603981B2 - Manufacturing method of aluminum tube containing optical fiber unit - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method of manufacturing an aluminum tube containing an optical fiber unit used for an optical fiber combined overhead ground wire (OPGW) and the like.

[Conventional technology]

Conventionally, as a method of manufacturing such an aluminum tube containing an optical fiber unit, an aluminum tape is continuously formed into a tubular shape by a forming roll, and the optical fiber unit is housed therein, and the seam is welded by a continuous seam welding device. Is welded to form an aluminum tube containing the optical fiber unit, and if necessary, the aluminum tube is drawn to reduce the diameter.

[Problems to be solved by the invention]

However, in this manufacturing method, it is necessary to perform seam welding stably over a long length, strict process control is required, and welding defects and the like occur, which is extremely minute. However, the production yield was poor, as the whole long product became defective.

[Means for solving the problem]

According to the present invention, an aluminum tube is continuously extruded using a friction drive type extruder provided with a heat shielding member in a hollow nipple, and an optical fiber unit is housed inside the aluminum tube. A method of manufacturing an aluminum tube containing an optical fiber unit, wherein the aluminum tube is reduced in diameter by performing a plurality of drawing processes at the same time as drawing the metal tube, wherein the heat shielding member includes a metal pipe through which an optical fiber unit is inserted, and the metal pipe. Characterized by having a thin metal tube wound around the outer periphery of the metal pipe and flowing a cooling medium for cooling the metal pipe.

 Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 shows an example of a manufacturing apparatus suitably used in the manufacturing method of the present invention. In the figure, reference numeral 1 denotes an optical fiber unit sending section. This optical fiber unit sending section 1
Is a known striated body delivery device for delivering the long optical fiber unit A wound around the delivery drum 2. The optical fiber unit A here is an optical fiber core, a unit composed of a plurality of optical fiber cores, a cable made of this unit or a transmission body using an optical fiber such as an optical fiber cord or an optical fiber tape core. Are generically referred to. The optical fiber unit A sent from the optical fiber unit sending section 1 is sequentially and continuously sent to an extruding device 3 that stores the optical fiber unit A in a hot-extrusion aluminum tube.

This extruder 3 is disclosed in Japanese Patent Application Laid-Open No. 47-31859,
No. 9-9246, Japanese Patent Publication No. 59-9247, etc., are improved extrusion devices called friction drive type extrusion devices or conform type extrusion devices. As shown in FIG. 4, a fixed shoe block 5, a hollow nipple 6, an extrusion die 7, and a heat shielding member 8. The drive wheel 4 is formed by forming a groove 10 serving as a metal introduction chamber 9 on the outer peripheral surface thereof, and is rotated by a drive shaft (not shown) in the direction of the arrow in the figure. The fixed shoe block 5 has an arc-shaped inner peripheral surface which is provided around and engaged with the outer peripheral surface of the drive wheel 4, and an extrusion chamber 11 following the metal introduction chamber 9 is formed inside the fixed shoe block 5. . An annular extrusion die is provided at the front of the extrusion chamber 11, and a hollow nipple 6 is provided at the rear. The hollow nipple 6 includes a cylindrical portion 6a and a flange portion 6b. The cylindrical portion 6a is coaxially inserted into the extrusion die 7 at a predetermined interval, and the flange portion 6b is fixed to the fixed shoe block 5. It is fixed to. The hollow portion of the hollow nipple 6 is open to an optical fiber knit insertion hole 12 formed in the fixed shoe block 5.

A cylindrical heat shielding member 8 is fixed to the inner wall of the hollow portion of the hollow nipple 6. This heat shielding member 8
As shown in FIG. 3, a copper alloy having good thermal conductivity, a metal thin tube 14 made of stainless steel or the like is spirally wound around an outer peripheral surface of a metal pipe 13 made of stainless steel or the like, It is brazed and integrally attached so that a cooling medium such as cooling water can flow through the thin metal tube 14. The heat shielding member 8 is connected to the hollow nipple 6 via a heat-resistant heat insulating material 15 such as asbestos or ceramic.
The optical fiber unit A inserted from the optical fiber unit insertion hole 12 of the fixed shoe block 5 is inserted into the hollow portion of the heat shielding member 8 coaxially.

In such an extrusion device 3, when the rod-shaped preheated aluminum material B is supplied to the entrance of the metal introduction chamber 9, the contact friction resistance between the groove 10 of the drive wheel 4 and the aluminum material B with the rotation of the drive wheel 4 is increased. As a result, the aluminum material B is sent into the metal introduction chamber 9 and further pressed into the extrusion chamber 11. In this state, cooling water or the like is caused to flow through the thin metal tube 14 of the heat shielding member 8, and the optical fiber unit A is inserted into the heat shielding member 8 through the optical fiber unit insertion hole 12. The optical fiber unit A is housed in the aluminum tube 16 having the inner and outer diameters defined by the cylindrical portion 6a and being continuously extruded. At this time, the inner diameter of the extruded aluminum tube 16 is considerably larger than the outer diameter of the optical fiber unit A due to the presence of the hollow nipple 6 and the heat shielding member 8.

The aluminum tube 16 containing the optical fiber unit A thus extruded is then sent to a cooling device 17, where it is cooled and then sent to a first drawing die 17 where it is subjected to cooling drawing. After the diameter is reduced, the first caterpillar type take-up machine 19 linearly takes it. A hollow plug is used for the drawing process during cooling using a drawing die, and a method of inserting an optical fiber unit A into the center hole of the plug to make the inside of the aluminum tube smoother and a method of drawing (no plug) are used. Can be applied. The diameter reduction ratio of the aluminum tube 16 in the first drawing die 18 is about 15 to 25%. In the drawing process, the aluminum tube 16 needs to be pulled out without bending the aluminum tube 16 itself. A pulling roll or the like that bends or winds the aluminum tube 16 cannot be used. This is because the diameter of the aluminum tube 16 is reduced by being subjected to the drawing process, whereby the scanning speed of the aluminum tube 16 after the drawing process is increased, and the internal optical fiber unit A is moved at the same speed as the increased traveling speed. To travel,
This is because if the aluminum tube 16 is bent and pulled, the optical fiber unit A will be damaged by the difference in running speed.

The aluminum tube 16 containing the optical fiber unit A taken by the first caterpillar type take-up machine 19 is further subjected to a cold drawing process by a second drawing die 20, and then is subjected to a second caterpillar type mounting machine 21. The take-up roll of the take-up device 22 is taken as an aluminum tube C containing an optical fiber unit.
Winded up by 23. Of course, if necessary, a third, fourth, fifth, etc. drawing die and a caterpillar type take-up machine can be provided to reduce the diameter of the aluminum tube 16 to a desired diameter.

According to such a manufacturing method, since the extruding device 3 is provided with the heat shielding member 8, the heat generated during the hot extrusion of the aluminum tube 16 is not transmitted to the optical fiber unit A. Is not thermally degraded. In addition, since the extruded aluminum tube A is subjected to cold drawing several times, work hardening occurs, and even if a soft aluminum tube 16 having good extrudability is extruded, it can be formed into an optical fiber composite overhead ground wire or the like. It will have the necessary hardness to be used. Further, since the diameter of the aluminum tube 16 is sequentially reduced, the traveling speed after the diameter reduction is faster than that at the time of extrusion, and the productivity is increased despite the use of the conform type extrusion device 3. Of course, the inconvenience caused by the welding of the conventional seam of the aluminum tube is also solved. Further, since the heat shielding member 8 has a metal pipe 13 through which the optical fiber unit is inserted, and a metal thin tube 14 which is provided by being wound around the outer circumference of the pipe and through which a cooling medium for cooling the metal pipe 13 flows. The metal pipe 13 is forcibly cooled by flowing a cooling medium through the thin metal tube, and the temperature inside the metal pipe 13 is reduced to a temperature necessary for protecting the optical fiber unit, thereby ensuring the thermal deterioration of the optical fiber unit. Can be prevented.

〔Example〕

SUS316 stainless steel pipe 13 with 0.5mm thickness and 5mm outer diameter
Then, a SUS304 stainless steel thin tube 14 having an outer diameter of 2 mm was spirally wound and brazed to form a heat shielding member 8, which was mounted in the hollow mandrel 6 of the extruder 3 as shown in FIG. The soft aluminum material B is extruded while flowing cooling water through the thin tube 15, and an aluminum tube 16 having an outer diameter of 20 mm and an inner diameter of 18 mm is extruded.
And the optical fiber unit A having an outer diameter of 3.0 mm was drawn from the heat shielding member 8. This was cooled, and then the drawing die and the caterpillar type take-up machine were respectively placed in the pipes.
Using a table to continuously reduce the diameter, the outer diameter of the aluminum tube 6mm,
The inner diameter was 4.8 mm.

The transmission characteristics and the like of the optical fiber unit of the aluminum tube containing the optical fiber unit thus obtained were not different from those at the beginning, and no abnormality was recognized. No defects such as pinholes were observed in the aluminum tube, and the aluminum tube was suitable for use as an optical fiber composite overhead ground wire.

〔The invention's effect〕

As described above, the method of manufacturing an aluminum tube containing an optical fiber unit according to the present invention continuously extrudes an aluminum tube using a friction drive type extruder provided with a heat shielding member in a hollow nipple, and separates the aluminum tube from the aluminum tube. After the optical fiber unit is stored in the aluminum tube, the aluminum tube is pulled out linearly and at the same time, the aluminum tube is reduced in diameter by performing a plurality of drawing processes. The tube can be manufactured continuously without defects and without deterioration of the optical fiber unit. Also, since the diameter of the aluminum tube is reduced by drawing, the final aluminum tube with the optical fiber unit can be manufactured at a speed higher than the extrusion speed of the aluminum tube, and the productivity is good.
In addition, the aluminum tube is hardened by the work hardening by the drawing process, and has a strength suitable for an optical fiber composite overhead ground wire and the like. Further, since the heat shielding member has a metal pipe through which the optical fiber unit is inserted, and a metal thin tube which is provided to be wound around the outer periphery of the metal pipe and through which a cooling medium for cooling the metal pipe flows, the cooling medium is provided. Is forced into the thin metal tube to forcibly cool the metal pipe, reduce the temperature inside the metal pipe to a temperature necessary for protecting the optical fiber unit, and reliably prevent thermal deterioration of the optical fiber unit.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an example of a manufacturing apparatus used in the manufacturing method of the present invention, FIG. 2 is a schematic sectional view showing an example of an extruding apparatus in FIG. 1, and FIG. It is the schematic sectional drawing which expanded the part. 1 ... optical fiber unit sending section, A ... optical fiber unit, 3 ... extrusion device, 6 ... hollow nipple, 8 ...
Heat shielding member, 16 ... aluminum tube, 18 ... first drawing die, 19 ... first caterpillar type take-up machine, 20 ... second
Tubing dies, 21 …… second caterpillar take-up machine, 22 ……
Winding device, C ... Aluminum tube containing optical fiber unit.

Claims (1)

(57) [Claims] 1. An aluminum tube is continuously extruded using a friction drive type extruder provided with a heat shielding member in a hollow nipple, and an optical fiber unit is housed inside the aluminum tube. A method for manufacturing an aluminum tube containing an optical fiber unit, in which the aluminum tube is reduced in diameter by performing a plurality of drawing processes at the same time as drawing straight, wherein the heat shielding member is a metal pipe through which the optical fiber unit is inserted. A method for manufacturing an aluminum tube containing an optical fiber unit, comprising: a metal thin tube wound around an outer periphery of a metal pipe and flowing a cooling medium for cooling the metal pipe.