JP4538372B2 - Slot type optical fiber cable and manufacturing method thereof - Google Patents

Description

  The present invention relates to a slot-type optical fiber cable that improves loss characteristics and at the same time improves roundness, and a method for manufacturing the same.

  A conventional slot-type optical fiber cable has a structure as shown in Patent Document 1, for example. That is, referring to FIG. 4, the slot type optical fiber cable 101 includes a long slot 105 having a tensile body 103 at the center, and the outer periphery of the slot 105 is appropriately spaced at equal intervals, for example. Three slot grooves 107 are formed. In each slot groove 107, for example, four optical fiber tape cores 109 as optical fibers are laminated in a plurality of layers, for example, three layers.

  For example, a tape winding 111 (metal tape) as a press winding tape is vertically wound around the outer periphery of the slot 105. This state is generally called a cable core 113. The outer periphery of the tape winding 111 in the cable core 113 is covered with a jacket 115 made of, for example, a thermoplastic resin.

  Further, as shown in FIG. 5, the above-mentioned four-fiber optical fiber ribbon 109 has four optical fiber strands 117 arranged in a horizontal row, and the plurality of optical fiber strands. The outer periphery of 117 is covered with a batch resin 119 such as a UV resin.

  The optical fiber 117 is formed by coating the outer periphery of a bare optical fiber 121 generally made of glass (quartz) with a coating resin 123 such as UV resin.

  The manufacturing method of the slot type optical fiber cable 101 will be described below. As shown in FIG. 6, the cable core 113 in which a tape winding 111 (metal tape) is wound around the outer periphery of the slot 105. 6 is run from the left to the right in FIG. 6 in the nipple 127 of the extrusion device 125, and the thermoplastic resin 131 serving as the outer jacket 115 is inserted and extruded from between the die 129 and the nipple 127 to form a slot type. An optical fiber cable 101 is manufactured.

Further, in Patent Document 2, as a method of manufacturing a plastic pipe with a conductive path, a hot-melted plastic material is extruded into a pipe shape, and a high pressure gas is injected into a hollow portion of the extruded pipe to form a predetermined pipe. How to do is known.
JP-A-11-142701 Japanese Patent Laid-Open No. 4-62024

  By the way, in the case of the conventional slot type optical fiber cable 101 described above, as the slot groove 107 of the slot 105 becomes larger, the outer diameter of the slot 105 and the outer diameter to the bottom of the slot groove 107 become larger as shown in FIG. The difference between the outer diameter and the outer diameter increases, and even if the jacket 115 is covered, the outer diameter difference appears as an appearance of the slot type optical fiber cable 101.

  If irregularities appear in the shape of the slot groove 107 in the appearance of the slot type optical fiber cable 101, for example, the shape of the upper slot groove 107 in FIG. 4, when the slot type optical fiber cable 101 is connected, for example, a commercially available jacket removal tool However, since the blades do not uniformly enter the outer jacket 115, the outer jacket 115 is difficult to peel off, and when laying, the resistance of the entire slot-type optical fiber cable 101 in the conduit increases. Accordingly, when considering only eliminating the irregularities in the shape of the slot groove 107, the thickness of the outer cover 115 increases in the slot groove 107 portion, and the outer cover material of the outer cover 115 falls into the slot groove 107 portion, It is conceivable that a side pressure is applied to the optical fiber ribbon 109 to increase the loss.

Further, the coating of the outer jacket 115 in the slot type optical fiber cable 101 is performed by coating the thermoplastic resin 131 on the slot 105 in a pipe shape in the manufacturing process shown in FIG. There is a drawback that the shape of the cable core 113 tends to appear as shown in FIG. As a countermeasure, the withdrawal rate = π / 4 (Id ² −Dn ² ) / π / 4 (D ² −d ² ) × 100% (where Id is the inner diameter of the die 131, Dn is the outer diameter of the nipple 129, Measures are taken to assemble the dice 129 and the nipple 127 so that the withdrawal rate expressed by d: outer diameter of the cable core 111 and D: outer diameter of the jacket 115) is smaller than the normal value. However, depending on the type of the thermoplastic resin 131, there are manufacturing problems such as difficulty in molding and deterioration of the surface condition.

  On the other hand, a method of forming a predetermined pipe by ejecting high pressure gas into a hollow portion of the extruded pipe while extruding a heated and melted plastic material into a pipe shape as shown in the above-mentioned conventional patent document 2 In this case, a conductive substance is fed into the hollow portion of the pipe together with the high-pressure gas to form a uniform conductive path over the entire inner surface of the pipe, which can be used as a means for eliminating irregularities in the shape of the slot groove 107. It is not possible.

  The present invention has been made to solve the above-described problems.

In order to achieve the object to be solved by the invention, a slot type optical fiber cable according to the invention accommodates a slot having a strength member at the center and optical fibers formed at appropriate intervals on the outer periphery of the slot. A cable core is configured by a slot groove for performing and a holding tape wound around the outer periphery of the slot in a state in which the optical fiber is accommodated in each slot groove, and the outer periphery of the holding tape in the cable core A slot-type optical fiber cable configured by covering the outer cover with a sheath, wherein a gap is formed between the press-wrapping tape immediately above each slot groove in the cable core and the outer cover , is formed deeper than the height of said optical fiber, said a holding tape directly above each slot groove, a gap is provided between the optical fiber It is characterized in that there. In the slot type optical fiber cable of the present invention, it is preferable that the jacket is formed of a thermoplastic resin.

The manufacturing method of the slot type optical fiber cable according to the present invention includes a slot having a strength member at the center, a slot groove for accommodating optical fibers formed at appropriate intervals on the outer periphery of the slot, and the slots. A cable core made of a holding tape wound in a state where the optical fiber is housed in a groove is caused to travel into a nipple of an extrusion device, and a thermoplastic resin as an outer sheath is made into a die and a nipple of the extrusion device. In the manufacturing method of the slot type optical fiber cable for manufacturing the slot type optical fiber cable inserted and extruded between
When the thermoplastic resin is extruded, mist-like moisture is fed into the outer periphery of the press-wound tape in the cable core together with compressed air in the nipple.

  As can be understood from the description of the means for solving the problems as described above, according to the slot type optical fiber cable and the method of manufacturing the same of the present invention, the optical fiber is wound in each slot groove. The cable core made of the holding tape is run into the nipple of the extrusion device, and the thermoplastic resin as the outer cover is inserted between the die and the nipple of the extrusion device and extruded to produce a slot type optical fiber cable. At the time of extrusion of the thermoplastic resin, by sending mist-like moisture together with compressed air to the outer periphery of the press-wrapping tape in the cable core in the nipple, the outer shell bulges concentrically under the internal pressure, and immediately above each slot groove A gap can be formed between the press-wrapping tape and the outer cover, and the outer cover falls in the slot groove It can be avoided.

  As a result, the jacket does not press the optical fiber, and an increase in transmission loss of the optical fiber can be suppressed.

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

  Referring to FIG. 1, a slot-type optical fiber cable 1 includes a long slot 5 having a strength member 3 at the center, and three slots 5 at equal intervals on the outer periphery of the slot 5. Slot groove 7 is formed. In each slot groove 7, for example, four optical fiber tape cores 9 as optical fibers are laminated in a plurality of layers, for example, three layers.

  For example, a tape winding 11 (metal tape) as a press winding tape is vertically wound around the outer periphery of the slot 5. This state is usually called a cable core 13. The outer periphery of the tape winding 11 in the cable core 13 is covered with a jacket 15 made of, for example, a thermoplastic resin.

  Further, as shown in FIG. 2, the four optical fiber ribbons 9 have four optical fiber strands 17 arranged in a horizontal row, and the plurality of optical fiber strands. The outer periphery of 17 is collectively covered with a batch resin 19 such as a UV resin.

  The optical fiber 17 is formed by coating the outer periphery of a bare optical fiber 21 generally made of glass (quartz) with a coating resin 23 such as a UV resin.

  Referring again to FIG. 1, a gap (gap) 25 is formed between the tape winding 11 immediately above each slot groove 7 in the cable core 13 and the jacket 15. By providing this gap 25, the thickness of the outer jacket 15 becomes uniform, and the drop in the slot groove 7 can be prevented.

  As a result, the outer jacket 15 does not press the optical fiber ribbon 9 and an increase in transmission loss of the optical fiber ribbon 9 can be suppressed.

  The manufacturing method of the slot-type optical fiber cable 1 will be described. As shown in FIG. 3, the cable core 13 in which the tape winding 11 (metal tape) is wound around the outer periphery of the slot 5 is vertically attached. 3 is moved from the left side to the right side in FIG. 3 in the nipple 29 of the extrusion device 27, and the thermoplastic resin 33 serving as the outer cover 15 is inserted and extruded from between the die 31 and the nipple 29 to form a slot type. The optical fiber cable 1 is manufactured.

  When this slot type optical fiber cable 1 is manufactured, when extruding the thermoplastic resin 33, by sending mist-like moisture together with compressed air into the outer periphery of the tape winding 11 in the cable core 13 in the nipple 29, Since it is possible to simultaneously increase the internal pressure of the outer cover 15 and cool the inner surface of the outer cover 15 during coating, the tape windings 13 directly above the slot grooves 7 and the outer cover can be obtained as shown in FIG. A gap (gap) 25 is formed between the cover 15 and the cover 15. By forming this gap (gap) 25, the slot-type optical fiber cable 1 can be finished in a cylindrical shape with improved roundness.

  As described above, the thickness of the outer jacket 15 becomes uniform, and the drop in the slot groove 7 can be prevented. As a result, the outer jacket 15 does not press the optical fiber ribbon 9 and an increase in transmission loss of the optical fiber ribbon 9 can be suppressed.

  A prototype 100-fiber SZ slot type optical fiber cable 1 was manufactured by the above-described manufacturing method, and its loss characteristic, jacket removal property, and change in outer diameter were investigated.

  As a result, the results of the loss characteristics and the coat removal are as follows.

◇ Cable loss characteristics As a result of loss measurement at a loss temperature characteristic evaluation of −30 ° C. to + 70 ° C. × 3 cycles, a maximum loss increase was 0.03 dB / km in this temperature range, and good loss characteristics were obtained. Further, the protrusion of the slot 5 after the heat cycle was not recognized.

◇ Outer stripping property As a result of a cable sheath removal test using a commercially available cable sheath removal tool, the sheath 15 could be removed without damaging the tape winding 11, the slot 5, and the like.

It is sectional drawing of the slot type optical fiber cable of this invention. FIG. 2 is an enlarged cross-sectional view of a four-fiber optical fiber ribbon showing an example of an optical fiber housed in a slot groove in FIG. 1. It is the figure which showed the cross-sectional view state in the extrusion apparatus which manufactures the slot type optical fiber cable of this invention. It is a perspective view of the conventional slot type optical fiber cable. FIG. 5 is an enlarged cross-sectional view of a four-fiber optical fiber ribbon showing an example of an optical fiber housed in the slot groove in FIG. 4. It is the figure which showed the cross-sectional view state in the extrusion apparatus which manufactures the conventional slot type optical fiber cable.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Slot type optical fiber cable 3 Strength member 5 Slot 7 Slot groove 9 Optical fiber tape core wire 11 Tape winding (pressing winding tape)
13 Cable core 15 Outer sheath 17 Optical fiber wire 19 Collective resin 21 Bare optical fiber 23 Coating resin 25 Air gap (gap)
27 Extruder 29 Nipple 31 Die 33 Thermoplastic Resin

Claims (3)

A slot having a tensile body in the center, a slot groove for accommodating optical fibers formed at appropriate intervals on the outer periphery of the slot, and the slot in a state where the optical fiber is accommodated in each slot groove A slot-type optical fiber cable configured by forming a cable core with a press-wound tape wound around the outer periphery of the cable core and covering the outer periphery of the press-wound tape in the cable core with a jacket;
A gap is formed between the press-wrapping tape immediately above each slot groove in the cable core and the jacket,
The slot-type optical fiber cable , wherein each slot groove is formed deeper than the optical fiber, and a gap is provided between the holding tape just above each slot groove and the optical fiber. . The slot-type optical fiber cable according to claim 1,
The outer jacket is formed of a thermoplastic resin, and is a slot type optical fiber cable. A slot having a strength member at the center, a slot groove for accommodating optical fibers formed at appropriate intervals on the outer periphery of the slot, and a state in which the optical fiber is accommodated in each slot groove. A cable core made of the holding tape is run into the nipple of the extrusion device, and a thermoplastic resin serving as a jacket is inserted between the die and the nipple of the extrusion device and pushed out to form a slot type optical fiber cable. In the manufacturing method of the slot type optical fiber cable to manufacture,
A method of manufacturing a slot-type optical fiber cable, wherein mist-like moisture is fed together with compressed air into the outer periphery of a press-wound tape in the cable core in the nipple when the thermoplastic resin is extruded.

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