JP2003131095A - Method for manufacturing optical fiber cable unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing an optical fiber cable unit which can apply a fused resin to a twisted wire while constituting the twisted wire by twisting a group of optical fibers without sucking air. SOLUTION: The twisted wire of a plurality of the optical fibers 1 is twisted in the vicinity of an entrance 2A of a coating nipple. The fused resin 4 is ejected to a slope 5B on the front face of a nipple holder in the vicinity of the coating nipple, is made to flow from the slope into the entrance of the coating nipple located under a surface 2B via an upper part of the surface 2B of the coating nipple and the surface, and is applied to the twisted wire.

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 cable unit in which a plurality of optical fiber element wires are twisted together and a molten resin is applied around them.

[0002]

2. Description of the Related Art As an example of this type of cable unit, an optical submarine cable unit is known as shown in FIG. That is, a plurality of optical fiber strands 1 are twisted around a tensile strength member TM, for example, a steel wire, a copper-plated steel wire, a twisted steel wire in which a plurality of thin steel wires are twisted, and the outside thereof. Then, the ultraviolet curable resin 4 is applied to the optical fiber element wire 1 and the optical fiber element wire 1 is integrally fixed to the strength member TM, and then the outer cover S is extruded and coated on the outside thereof.

When manufacturing this cable unit, a method shown in FIG. 3 is known as a conventional method for applying a molten resin especially to the outside of the stranded wire of the optical fiber element wire.

That is, the apparatus used in this method is a pressurizing chamber 5 for filling the molten resin in a nipple holder 5 for supporting the coating nipple 2 of the molten resin and applying pressure.
A is formed, and the coating nipple 2 is attached to the entrance of this pressure chamber.

The coating nipple 2 has a disk shape, and a twisted wire guide hole for guiding a twisted wire 3 to be described later is bored in the central portion thereof, and the entrance of this guide hole constitutes a coating nipple entrance 2A.

A passage hole for the cable unit, the surface of which is coated with molten resin, is formed at the outlet of the pressurizing chamber.

A molten resin supply pipe 6 for discharging the molten resin 4 having a relatively high viscosity is mounted above the front surface of the nipple holder 5.

Further, the pressure chamber 5A of the nipple holder 5
A molten resin press-fitting pipe 7A for press-fitting the molten resin from the outside of the nipple holder casing is communicated with, and a molten resin of the same type as the molten resin 4 is press-fitted from this pipe 5A. In addition, 7B is a discharge pipe for discharging a part of the molten resin in the pressurizing chamber.

Therefore, a plurality of running optical fiber strands 1 are continuously supplied to the coating nipple 2, and each bobbin around which each optical fiber strand is wound is twisted by a twisting machine (not shown). ), The twisted wire is applied to the wire group in the vicinity of the coating nipple entrance 2A to form the twisted wire 3.

At this time, the molten resin 3 having a relatively high viscosity is discharged from the molten resin supply pipe 6 in a substantially vertical direction, and the molten resin is applied around the twisted optical fiber element group. It

[0011]

In the above conventional method, the position where the molten resin 4 to be discharged and the optical fiber element wire group to be twisted first come into contact with each other when the optical fiber element wire group is twisted Since the gathering point, that is, not in the vicinity of the coating nipple inlet 2A, but in front of the coating nipple inlet 2A, the resin collects ambient air until the coating nipple inlet 2A is reached after these strands are twisted together. I will get involved.

Further, due to the viscosity of the molten resin and the shape of the outlet of the molten resin supply pipe 6, the nipple inlet 2A
In combination with the fact that the shape in which the molten resin accumulates is unstable, the molten resin entrains air and causes the inconvenience that air bubbles are mixed into the resin.

On the other hand, in order to solve this problem, Japanese Unexamined Patent Application Publication No.
The devices of JP-A-62-475 and JP-A-2000-241690 are known, but these devices have a complicated structure for rotating a coating nipple (die) and have a problem that a special rotating mechanism is required. .

According to the present invention, when the molten resin is applied to the stranded wire by advantageously solving the above problems and applying the molten resin to the stranded wire, air is not entrained in the molten resin and air bubbles are hardly mixed in the resin. An object is to provide a method for manufacturing a fiber cable unit.

[0015]

SUMMARY OF THE INVENTION In order to achieve the above object, the first object of the present invention is to provide a plurality of optical fiber strands continuously supplied to a coating nipple. The strands are twisted near the entrance of the coating nipple to form a stranded wire, and the molten resin is discharged toward the nipple holder inclined surface near the coating nipple, and the discharged molten resin is discharged from the inclined surface to the surface of the coating nipple. It is configured such that the molten resin is applied to the twisted wire by flowing through the upper part and further on the surface to the entrance of the coating nipple on the lower part of the surface.

A second problem-solving means is the same as the first problem-solving means, in which the optical fiber cable unit has a structure in which optical fiber strands are twisted around a strength member and the molten resin applied is an ultraviolet curable resin. Has been adopted.

The operation of the first means for solving problems is that air bubbles are hardly entrained in the molten resin applied to the stranded wire.

The operation of the second means for solving problems is effective for manufacturing a submarine optical cable.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIG.

The apparatus used in the method of the present invention is provided with a pressurizing chamber 5A for filling and pressurizing the molten resin in a nipple holder 5 which supports the coating nipple 2 of the molten resin. A coating nipple 2 is attached to the entrance.

The front surface of the nipple holder 5 has a conical tapered curved surface 5B toward the coating nipple 2.

The coating nipple 2 has a disk shape, and a twisted wire guide hole for guiding the twisted wire 3 is bored in the center thereof, and the entrance of this guide hole constitutes the coating nipple entrance 2A.

On the other hand, a passage hole for a cable unit whose surface is coated with a molten resin is formed at the outlet of the pressurizing chamber.

A discharge hole 5C for discharging the molten resin 4 having a relatively high viscosity is formed from the top of the coating die holder 5 toward the tapered curved surface 5B near the coating nipple entrance 2A. A molten resin supply pipe 6 is attached to the entrance of the.

Further, a filling pipe 7A for filling a molten resin different from the molten resin 4, usually a molten resin of the same kind as the molten resin 4, is connected to the pressure chamber 5A, and the pressure chamber 5A is also connected.
A discharge pipe 7B is provided in the pressurizing chamber 5A for exhausting a part of the molten resin inside, for example, the molten resin in the pressurizing chamber where air is mixed for some reason and is foamed out of the pressurizing chamber. It is in communication.

Therefore, in order to manufacture an optical fiber cable unit by the above apparatus, a plurality of running optical fiber strands 1 are continuously supplied to the coating nipple 2 while these optical fiber strand groups are being supplied. When the bobbin of the optical fiber element wire is revolved by the twisting machine to impart a twist, the coating nipple inlet 2A serves as a gathering point for twisting the optical fiber element wire group, and the twisted wire 3 is formed.

At this time, the molten resin 4 having a relatively high viscosity is vertically discharged from the discharge pipe 6 through the flow path 5A, and the discharged resin has a cone shape having an inclination due to its rheological behavior due to its viscosity and viscoelasticity. The curved surface 5B of the coating nipple reaches the surface 2B of the coating nipple without falling down.

The resin that has reached the surface 2B of the coating nipple further flows along the surface 2B and reaches the entrance 2A of the coating nipple. For the first time, the molten resin 4 is wetted and applied to the surface of the stranded wire 3 of the optical fiber element wire group passing through the entrance 2A.

In other words, the portion where the molten resin 4 first comes into contact with the stranded wire 3 of the optical fiber element wire is the gathering point of the optical fiber element wire group, that is, the coating die inlet 2A.

Therefore, the molten resin comes into contact first near the gathering point of the group of optical fiber strands,
In addition, in combination with the stable accumulation of the molten resin at the nipple entrance 2A, the molten resin is extremely less likely to entrap air and mix bubbles.

When air enters the molten resin in the pressurizing chamber 5A for some reason to generate bubbles, the exhaust pipe 7B is temporarily opened to exhaust this part to the outside of the pressurizing chamber. Has been done.

Normally, the discharge pipe 7B is closed, and the molten resin filled from the filling pipe 7A is filled under the sufficient pressure outside the molten resin 4 supplied from the molten resin supply pipe 6 and twisted. The resin is sufficiently filled even in the minute gaps between the optical fiber strands forming the wire 3.

A tensile strength member such as a steel wire, a copper-plated steel wire, or a twisted steel wire in which a plurality of thin steel wires are twisted together is arranged at the center of the twisted wire 3, and the molten resin 4 is ultraviolet-cured. In the case of a cable unit which is a mold resin, that is, a cable knit of a submarine optical fiber cable, an extrusion for coating a curing device (ultraviolet irradiation device) of an ultraviolet curable resin and an outer sheath of the cable downstream of the nipple holder 5. A molding machine is installed.

[0034]

As described above, according to the present invention, the stranded wire comes into contact with the molten resin at the gathering point of the optical fiber element wire group, and the pooled state of the molten resin is stabilized at the nipple entrance 2A. As a result, the molten resin is extremely unlikely to entrap air and mix bubbles.

Here, the application conditions of the molten ultraviolet-curable resin according to the present invention and the conventional method were compared and examined, and the results are shown in Table 1. As shown in this table, it is understood that, according to the method of the present invention, the molten resin pool condition at the nipple inlet is good and the bubble content is extremely low regardless of the resin viscosity.

[0036]

[Table 1]

[Brief description of drawings]

FIG. 1 is a sub-sectional view showing an example of the method of the present invention.

FIG. 2 is a sectional view showing an example of an optical fiber cable unit manufactured according to the present invention.

FIG. 3 is a sub-sectional view showing a conventional method.

[Explanation of symbols] 1 optical fiber strand, 2 coating nipple, 2A
Coating nipple entrance, 3 strands, 4 molten resin, 5 nipple holder, 5A pressure chamber, 5B conical inclined surface, 5C molten resin supply hole, 6 molten resin supply pipe, 7A molten resin filling pipe, 7B molten resin discharge pipe

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Takeshi Shimichi             1440 Rokuzaki, Sakura City, Chiba Prefecture Fujikura Ltd.             Sakura office (72) Inventor Keiji Ohashi             1440 Rokuzaki, Sakura City, Chiba Prefecture Fujikura Ltd.             Sakura office F term (reference) 2H001 BB06 DD21 MM05

Claims (3)

[Claims] 1. A plurality of optical fiber strands (1) are continuously supplied to a coating nipple (2), and these optical fiber strands are twisted in the vicinity of a coating nipple entrance (2A) to form a stranded wire. An inclined surface (5B) that forms the molten resin (4) toward the coating nipple above the nipple holder near the coating nipple while forming (3).
The molten resin discharged from the inclined surface is passed through the inclined surface through the upper portion of the coating nipple surface (2B) and further flows through the surface to the inlet of the coating nipple at the lower portion of the surface, and the molten resin is applied to the twisted wire. A method for manufacturing an optical fiber cable unit, characterized in that it is configured to be applied. 2. The optical fiber cable unit according to claim 1, wherein the plurality of optical fiber strands (1) are twisted around a strength member, and the molten resin is an ultraviolet curable resin. Manufacturing method. 3. The optical fiber according to claim 1, wherein the twisted wire (3) coated with the molten resin by the coating nipple (2) is further sent to a pressure chamber and coated with the molten resin. Cable unit manufacturing method.