JP2002055265A - Method for manufacturing optical fiber unit and apparatus for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coating method by which coated optical fibers are stranded to a uniform array and the intrusion of air bubbles is averted in forming a UV resin coating of an optical fiber unit and a coating die device. SOLUTION: When the optical fiber unit is manufactured by stranding a plurality of the coated optical fibers 12 around a central tension member 11 and coating the entire part with the UV resin 13 in manufacture of the optical fiber unit, a plurality of the coated optical fibers 12 are precoated with the UV resin 13 at a point F before aggregating and stranding of a plurality of the coated optical fibers 12 are completed and, in succession, the stranding of the tension member 11 and a plurality of the coated optical fibers 12 is completed at a point P and the entire part is coated with the UV resin 13 at a point S following the same. As a result, the optical fiber unit, which is stranded with the coated optical fibers 12 around the tension member 11 with the uniform array and is not intruded with the air bubbles in the coating resin 13 is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an optical fiber unit in which a plurality of optical fiber cores are twisted around a central tensile strength wire and assembled to be coated with an ultraviolet curing resin and integrated. And manufacturing equipment.

[0002]

2. Description of the Related Art Submarine optical fiber cables require the strictest reliability among optical fiber cables. However, in recent years, further expansion of transmission capacity and longer distance between relay stations have been demanded. What wasn't said was needed to be improved. The submarine optical fiber cable is constructed by housing the optical fiber unit in a metal tube tube, covering the outside of the metal tube tube with a steel strand, and further armoring the outside with a copper tube, polyethylene insulation layer and polyethylene sheath. .

In an optical fiber unit for a submarine optical fiber cable, six to eight optical fiber cores are twisted around a central tensile strength line, and the whole is made of an ultraviolet-curable resin (hereinafter, referred to as a resin).
UV resin). For the optical fiber core, a glass fiber having a nominal outer diameter of 0.125 mm is UV resin so that the outer diameter is 0.25 to 0.4 mm,
A pigment coated with a silicone resin or the like is used.

FIG. 6 shows a conventional optical fiber unit having a UV.
The outline of the resin coating method is shown. In the figure, 1 is a tensile strength wire, 2 is an optical fiber core, 3 is a UV resin coating, 4 is a coating die device, and 5 is an ultraviolet irradiation furnace. The plurality of optical fiber cores 2 are paid out from respective supply reels (not shown), and are drawn into the coating die apparatus 4 while being twisted around the tensile strength wire 1 (usually a steel wire is used). The tensile wire 1 and the plurality of optical fibers 2 are
The assembly is completed at the point P in the coating die apparatus 4 to complete the twisting, and then the UV coating 3 is applied and molded, and the ultraviolet irradiation furnace 5
To cure the coating and move on to the next step. In the next step, a secondary coating is further applied as necessary, or the film is wound as it is by a winding device (not shown).

FIG. 7 schematically shows a coating die apparatus 4 for implementing the conventional UV resin coating method for an optical fiber unit shown in FIG. 6, in which 6 is a nipple, 7 is a die, 8 is a sleeve,
Reference numeral 9 denotes a resin inlet, and 10 denotes a resin outlet. The coating die device 4 is configured by fitting a nipple 6 and a die 7 into a cylindrical sleeve 8. The strength member 1 and the optical fiber core 2 are drawn into the coating die device from the smooth cone-shaped inlet of the nipple 6 while being twisted, and are coated with the UV resin injected from the resin supply port 9. The air and the resin mixed with the air in the initial stage of the coating start are discharged from the resin discharge port 10.

In the UV resin coating by the above-mentioned conventional method and apparatus, the UV resin is applied after the tensile strength wire 1 and the optical fiber 2 are completely twisted. For this reason, the UV resin is not uniformly applied to the entire surface of the optical fiber core wire 2, and the optical fiber core wire 2 moves in the coating die device 4 and the arrangement is not constant. Therefore, if the resin is applied near the entrance of the nipple, a large amount of air bubbles are mixed in the unit, which increases transmission loss.

FIG. 8 shows a UV resin-coated section of an optical fiber unit formed by a conventional method. The optical fiber cores 2 are arranged in a circle around the tensile strength wire 1, but the optical fiber cores 2 are arranged in a circle. The spacing between the lines 2 was uneven and the arrangement was non-uniform, and the bubbles 11 were mixed. If the arrangement of the optical fiber cores 2 is disturbed or bubbles are present in the UV resin coating 3, transmission loss increases due to lateral pressure or temperature change, and transmission characteristics become unstable.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has been made in consideration of the above-mentioned problems.
Provided are a coating method and a coating die apparatus in which optical fiber core wires are twisted in a uniform arrangement when forming a resin coating and in which bubbles are not mixed.

[0009]

In manufacturing an optical fiber unit, when manufacturing an optical fiber unit in which a plurality of optical fiber core wires are twisted around a central tensile strength member and the whole is covered with resin, the above-mentioned plurality of optical fiber units are required. Before assembling and twisting the optical fiber cores, a plurality of optical fiber cores are pre-coated with UV resin, and then the twisting between the tensile strength member and the optical fiber cores is completed. Thereafter, the whole is coated with a UV resin. As a result, the optical fiber core wires are twisted in a uniform arrangement around the tensile strength wire, and an optical fiber unit in which bubbles are not mixed into the coating resin is formed.

[0010]

1 and 2, an embodiment of the present invention will be described. FIG. 1 is a view schematically showing a UV resin coating method for an optical fiber unit according to the present invention, and FIG. 2 is a partial schematic view of a coating die apparatus for performing the coating method of FIG. In the figure, 11 is a tensile wire, 12 is an optical fiber core, 1
3 is a UV resin coating, 14 is a coating die apparatus, 15 is an ultraviolet irradiation furnace, 16 is a nipple, 17 is a die, 18 is a sleeve, 19 is a resin supply port, 20 is a resin discharge port, 21 is a precoat nipple, and 22 and 23. Denotes a resin reservoir, and 24 denotes a flow path.

In the present invention, as shown in FIG. 1, a plurality of optical fiber cores 12 are unreeled from respective supply reels (not shown) and twisted around a tensile strength wire 11 to form a coating die apparatus. It is drawn into 14. The tensile strength wire 11 and the plurality of optical fiber cores 12 are in a state before the optical fiber cores 12 are assembled and twisted at the point F in the coating die apparatus 14, and the tensile strength of the optical fiber cores 12 and A gap remains between the wire 11. At this point F, UV resin is supplied, and each of the optical fibers 12 is precoated with UV resin.

Thereafter, the optical fiber cores 12 are gathered around the tensile strength wire 11 at a point P in the coating die apparatus 14 to complete the twisting. The point P is set by adjusting the shape of the nipple in the coating die apparatus 14 and the tension of the optical fiber 12. At the subsequent S point, the UV resin is supplied again to the whole, and the UV resin coating 13 is applied. After this,
The resin coating is cured in the ultraviolet irradiation furnace 15 as in the conventional method, and the process proceeds to the next step.

The coating die apparatus 14 shown in FIG. 2 is constructed by assembling a nipple 16, a precoat nipple 21 and a die 17 coaxially with a cylindrical sleeve 18. A resin reservoir 22 having a gap H is formed between the nipple 16 and the precoat nipple 21.
The UV resin injected from 9 is divided and supplied by the flow path 24. The resin reservoir 22 corresponds to the point F in FIG. 1 and at this position, the UV is applied to the plurality of optical fiber cores 12 drawn from the smooth cone-shaped inlet of the nipple 16.
Precoat resin. Although the structure in which the resin is supplied to the resin reservoir 22 is divided in the flow path 24, the resin may be supplied in a flow path independent of the resin supply port 19.

In the portion of the resin reservoir 22, the plurality of optical fiber cores 12 are in an open state where assembly and twisting are not completed, and UV resin is applied around each optical fiber core 12. Is done. The plurality of optical fiber cores 12 precoated with UV resin are used as precoated nipples 2.
At point P near the exit of the first tapered hole, the pieces are assembled and twisting is completed. The point P in FIG. 2 is the same as the point P shown in FIG.

A resin reservoir 23 is formed between the precoat nipple 21 and the die 17, and UV resin is supplied from a resin supply port 19. This resin reservoir 23 corresponds to S in FIG.
It is equivalent to a point. The air and the resin mixed with air in the initial stage of the coating start are discharged from the resin outlet 2
Emitted from 0. The plurality of optical fiber cores 12 twisted with the center tensile wire 11 having passed through the precoat nipple 21 are covered with a resin reservoir 23 so as to have a predetermined covering outer diameter, and are passed through a passage hole of the die 17. Molded.

Each of the optical fiber cores 12 is pre-coated with a UV resin before being collectively arranged around the central tensile strength member 11, so that the UV resin is applied to all the gaps between the optical fiber cores. It is filled, no bubbles are mixed in, no voids are generated, and the arrangement is uniform.

FIG. 3 is a diagram showing details of the nipple 6 and the precoat nipple 21. The nipple 6 has an inlet 25 for guiding a plurality of optical fibers into the coating die apparatus. The inlet 25 is formed in a smooth cone shape which is mirror-finished for smooth guiding without damaging the surface of the optical fiber core. Inlet 2
The hole diameter D at the exit end of No. 5 is set such that the optical fiber core wire is in contact with the center tensile line with a predetermined gap and is in a ring shape. An annular groove 27 is formed in the back wall 26 of the nipple 6 for assembling the pre-coated nipple 21 without axial deviation.

The precoat nipple 21 has a tapered hole 28 having a shape communicating with the inlet 25 of the nipple 6. The hole diameter E on the outlet side of the tapered hole 28 is set to be equal to or smaller than the hole diameter D on the outlet end of the nipple 24. The surface 29 on the inlet side of the tapered hole 28 is between the back wall 26 of the nipple 6 and
It is located behind the annular front end 30 so that a predetermined gap H (shown in FIG. 2) is formed. The front end 30 of the pre-coated nipple 21 is fitted in the annular groove 27 of the nipple 6 and is formed with high precision so as to be coaxial and relatively positioned. Further, the hole diameter E on the outlet side of the precoat nipple 21 is formed to be equal to or larger than the forming hole of the die 17. If the hole diameter E is smaller than the molding hole of the die 17, pores are easily generated in the resin coating.

FIG. 4 is a view showing the relationship between the central tensile wire 11 and the optical fiber core 12 at the point F at the precoat position in FIGS. A plurality of optical fiber cores 12
The shape of the inlet of the nipple 6 and the tension of the optical fiber are set so as to be spaced apart from the center tension line 11 by a predetermined gap G and to be positioned in a ring at uniform intervals.

FIG. 5 is a cross-sectional view of the optical fiber unit after the UV resin coating 13 is cured in the ultraviolet curing furnace 15 of FIG. The wires 12 are evenly twisted, and no bubbles are mixed.

Next, an embodiment of the present invention will be described with a specific example. 0.8mm outside diameter on tensile strength line of optical fiber unit
0.4m outer diameter for optical fiber core using steel wire
Eight nylon-coated fibers were used so that the finished outer diameter of the optical fiber unit was 1.95 mm.

First, at a point F to be precoated, a nipple is used to verify the gap G between the optical fiber core 12 and the center tensile wire 11 as shown in FIG. Of nipple Nos. 1-5
Was prototyped. Table 1 shows the results of each coating.

[Table 1]

As a result, the nipple No. In any of the cases 1 to 5, the arrangement of the optical fiber wires was good, and it was confirmed that the pre-coating of the UV resin before assembling into the tensile strength wire and twisting was effective. However, No. When the gap G is large as in 1 and 2, air bubbles are easily mixed. Therefore,
No. It is desirable that the gap G of 3 to 5 be in the range of 0.3 mm to 0.8 mm. The nipple outlet diameter D is
It is inevitably determined from the gap G, the diameter of the tensile strength wire used, and the diameter of the optical fiber core.

The gap H between the nipple 6 and the precoat nipple 21 shown in FIG.
And is desirably 0.8 mm to 1.6 mm. If it is less than 0.8 mm, sufficient precoating cannot be performed, and if it is more than 1.6 mm, air bubbles are likely to be mixed. A large amount of resin adheres to the finished outer diameter of the optical fiber unit +0.3 to 0.4 mm in the tapered hole of the precoat nipple 21.
Narrowed down to a degree. As a result, it is possible to prevent non-uniform arrangement of the optical fibers.

The UV resin used has a viscosity of 3.0 to 3.0.
Those having a range of 8.0 Pa · s are desirable. 3.0Pa ・
If it is less than s, air bubbles are likely to be mixed, and if it is more than 8.0 Pa · s, the arrangement of the optical fiber cores tends to be uneven.

[0026]

As is apparent from the above description, according to the present invention, each optical fiber core of the optical fiber unit has:
Before being assembled and arranged around the central strength member, UV
Since it is pre-coated uniformly with resin, it eliminates coating unevenness in the assembled and twisted state, keeps the intervals between optical fiber core wires even, and also has no gaps between optical fiber core wires. Filled with UV resin, it is possible to eliminate the incorporation of bubbles and the generation of cavities. Therefore, the optical fiber unit has a uniform optical fiber arrangement and excellent symmetry, and does not cause irregular bending of the fiber due to external pressure or the like.Therefore, an increase in process loss, an increase in water pressure loss, an increase in lateral pressure loss, and an increase in loss due to temperature change. Does not occur.

[Brief description of the drawings]

FIG. 1 is a schematic view illustrating a method of coating an optical fiber unit with a UV resin according to the present invention.

FIG. 2 is a schematic diagram of a coating die apparatus for performing the method of the present invention.

FIG. 3 is a view showing a nipple and a precoat nipple of the coating die apparatus of the present invention.

FIG. 4 is a diagram showing a positional relationship between optical fiber core wires during precoating according to the present invention.

FIG. 5 is a sectional view of an optical fiber unit formed according to the present invention.

FIG. 6 is a schematic view showing a method of coating a conventional optical fiber unit with a UV resin.

FIG. 7 is a schematic view of a coating die apparatus for performing a conventional method.

FIG. 8 is a sectional view of an optical fiber unit formed by a conventional method.

[Explanation of symbols]

11: Tensile wire, 12: Optical fiber core, 13: UV resin coating, 14: Coating die device, 15: UV irradiation furnace, 1
6: Nipple, 17: Die, 18: Sleeve, 19: Resin supply port, 20: Resin discharge port, 21: Precoat nipple, 22, 23: Resin reservoir, 24: Flow path, 25: Inlet,
28 ... Tapered hole.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Takehiko Okada 1st Tayacho, Sakae-ku, Yokohama-shi, Kanagawa Prefecture Sumitomo Electric Industries, Ltd. Yokohama Works (72) Inventor Yoshiaki Nagao 1st Tayacho, Sakae-ku, Yokohama-shi, Kanagawa Sumitomo F-term (reference) in Electric Manufacturing Co., Ltd. Yokohama Works 2H001 DD03 DD21 KK17 MM02 MM05 MM09 PP01 4G060 AA01 AC12 AC15 AD22 AD59 CB00

Claims (7)

[Claims] 1. A method of manufacturing an optical fiber unit, comprising: twisting a plurality of optical fibers around a central tensile member, and coating the whole with a resin, wherein the plurality of optical fibers are twisted. Before the completion, the plurality of optical fiber strands are pre-coated with the resin, and then the twisting of the tensile strength element and the plurality of optical fiber cores is completed, and thereafter the whole is covered with the resin. A method of manufacturing an optical fiber unit. 2. The optical fiber unit according to claim 1, wherein the precoating is performed at a position where a gap G between the optical fiber core wire and the tensile strength wire is 0.3 to 0.8 mm. Manufacturing method. 3. The method according to claim 1, wherein the resin is an ultraviolet curable resin (UV resin). 4. The method of manufacturing an optical fiber unit according to claim 3, wherein the viscosity of the ultraviolet curable resin (UV resin) is 3.0 to 8.0 Pa · s. 5. An apparatus for manufacturing an optical fiber unit, comprising twisting a plurality of optical fiber cores around a central tensile strength member and coating the whole with resin, wherein the plurality of optical fiber cores are assembled. A nipple for twisting and guiding is provided, and a die for coating and molding the resin, a precoat nipple is arranged between the nipple and the die, and the assembly is completed between the nipple and the precoat nipple to complete the twisting. Forming a resin reservoir for pre-coating the resin on the plurality of optical fiber cores before, between the die and the pre-coated nipple, the entirety of the plurality of optical fiber cores assembled and twisted. An apparatus for manufacturing an optical fiber unit, wherein a resin reservoir for covering the resin is formed. 6. The gap H between the resin reservoirs to be precoated is
The optical fiber unit manufacturing apparatus according to claim 5, wherein the optical fiber unit has a thickness of 0.8 to 1.6 mm. 7. A hole diameter E on the outlet side of the precoat nipple.
7. The apparatus for manufacturing an optical fiber unit according to claim 5, wherein a diameter of the die is equal to or larger than a diameter of a forming hole of the die.