JP2009237341A - Optical fiber cable and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To mount optical fibers with high density, and to make compatible both reduction in the diameter of an optical fiber cable and favorable transmission characteristics and impact resistance characteristics. <P>SOLUTION: An optical fiber cable 1 comprises: a cable core 5 into which a plurality of optical fibers 3 are aggregated; a plurality of sheets of protection tapes 9 which have widths shorter than the circumferential length of an outer periphery of the cable core 5 and the edges of which are lapped and vertically provided at the cable core 5 in the lengthwise direction of the cable core 5 to cover the outer periphery of the cable core; and a cable sheath 11 directly coated over outer peripheries of the plurality of protection tapes 9. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an optical fiber cable and a manufacturing method thereof, and more particularly, to an optical fiber cable and a manufacturing method thereof capable of mounting optical fibers at a high density and achieving both a reduction in cable diameter and characteristics.

  Conventionally, an optical fiber cable generally has a structure in which a sheath is provided after an optical fiber is mounted in a protective member such as a loose tube or a slot.

  For example, in the optical fiber cable of Patent Document 1, an optical fiber is placed in the groove of a sector having a groove parallel to the axis, and an optical unit is made by applying restraining winding (tape lateral winding) on the optical fiber. Is given a twist in the SZ direction.

  In the optical fiber cable of Patent Document 2, after storing the optical fiber core wire in the groove of the slot rod having a straight groove on the surface, a tape is vertically attached to the surface of the slot rod, and the outer periphery of the tape is Coarsely wound, and then the sheath is covered while twisting the slot rod in the SZ direction.

  The optical fiber cable of Patent Document 3 includes a cable core that is not pressed and a sheath that covers the periphery of the cable core and has a tear string inside the cable core. Since the cable core has no presser winding, it is easy to branch after the middle, and the sheath thickness between the cable core and the tear string is 0.3 to 0.9 mm, so the tear string is depressed in the cable core. To prevent it. Alternatively, by using a twisted string made of yarn as the above-described tear string, the impact resistance is ensured.

In the optical fiber cable (drop cable) of Patent Literature 4, a release sheet having a width wider than that of the optical fiber ribbon is vertically attached so as to cover both sides of the optical fiber ribbon.
JP-A-61-95307 Japanese Patent Laid-Open No. 9-43468 JP 2001-343569 A JP 2007-41382 A

  By the way, in the conventional optical fiber cable, as shown in Patent Document 1 and Patent Document 2, in a structure in which an optical fiber is mounted in a protective member such as a slot rod (or loose tube), the protective member is There is a problem that the mounting density of the optical fiber inevitably decreases as much as it exists.

  Therefore, a method of forming a cable core by gathering a plurality of optical fibers in a twisted or straight state without using the protective member and then pressing and winding the entire cable core includes Patent Document 1 and Patent Document As in the case of No. 2, rough winding is generally performed after tape winding or longitudinal tape attachment. However, in any of the methods of tape winding or tape vertical attachment, there is a problem in that if the optical fiber is directly wound around the optical fiber assembly, the optical fiber is tightened and loss is deteriorated.

  In order to solve this problem, in Patent Document 3, a sheath is directly sheathed on a cable core that is not pressed and wound, and a tear string (lip cord) is disposed on the inner surface of the cable sheath in consideration of an intermediate rear branch. In this case, when an impact force is applied from the outside, in order to prevent the phenomenon that the sheath of the part sandwiched between the tear string and the cable core is torn and the tear string is depressed in the cable core, the sheath thickness is increased, The outer diameter is increased by using a lot of yarn as a cushioning material in addition to using a twisted cord made of yarn as the tearing cord. However, the problem that the outer diameter of the cable becomes thick has not been solved.

  In Patent Document 4, a wide release sheet is only used for improving the separation property of the optical fiber.

  In the present invention, an optical fiber is mounted at a high density, and the optical fiber is sandwiched between a crack generated on the inner surface of the cable sheath due to an impact, a gap between the cracks, and the like. The purpose is to prevent this.

  In order to solve the above-mentioned problems, an optical fiber cable of the present invention is a cable core in which a plurality of optical fibers are assembled, and a plurality of protective tapes that are narrower than the circumference of the outer periphery of the cable core, A plurality of protective tapes that are wrapped in the longitudinal direction of the cable core by wrapping the edge portions of the respective protective tapes so as to cover the outer periphery of the cable core, and a cable sheath that directly covers the outer periphery of the plurality of protective tapes It is characterized by being comprised by these.

  In the optical fiber cable of the present invention, it is preferable that the protective tape is three or more in the optical fiber cable.

  The optical fiber cable of the present invention is the optical fiber cable, wherein the cable core is composed of a plurality of optical fiber units in which a plurality of optical fibers are assembled into a unit, and the plurality of optical fiber units. Are preferably twisted together.

  According to the optical fiber cable manufacturing method of the present invention, a plurality of optical fibers are assembled to form a cable core, and a plurality of protective tapes having a width smaller than the circumference of the outer periphery of the cable core are used. Wrap the edge of each protective tape to cover the outer periphery and vertically attach it in the longitudinal direction of the cable core, and manufacture the optical fiber cable by directly covering the outer periphery of this vertically attached protective tape with the cable sheath It is characterized by doing.

  The optical fiber cable manufacturing method of the present invention is the optical fiber cable manufacturing method, wherein the cable core is formed by assembling a plurality of optical fibers into a unit to form an optical fiber unit. It is preferable to gather the optical fiber units by twisting them together.

  As will be understood from the means for solving the above problems, according to the optical fiber cable and the manufacturing method thereof of the present invention, the edge portion of the protective tape is formed using a plurality of narrow protective tapes. By wrapping each other vertically on the outer periphery of the cable core, it is possible to obtain a good transmission characteristic by making a structure with a direct cable sheath without overlying a plurality of protective tapes. The impact resistance is also good, and it is possible to realize a small-diameter high-density cable. In addition, it is possible to prevent the optical fiber from being caught between cracks generated on the inner surface of the cable sheath when an impact is applied, or gaps between the cracks. Therefore, a multi-core optical fiber can be manufactured as an optical fiber cable having a small outer diameter, so that resources can be saved in terms of construction and distribution.

  Embodiments of the present invention will be described below with reference to the drawings.

  Referring to FIG. 1, an optical fiber cable 1 according to this embodiment is a cable in which a plurality of optical fibers 3 formed of an optical fiber, an optical fiber, an optical fiber tape, or other forms are assembled. A core 5 is provided.

  In this embodiment, the cable core 5 is formed by assembling a plurality of optical fibers 3 so that an optical fiber unit 7 is formed into a unit, and a plurality of the optical fiber units 7 are twisted and assembled. It consists of

  More specifically, the optical fiber 3 is a colored optical fiber strand having a diameter of, for example, 250 μmφ, and the optical fiber unit 7 is formed by collecting 20 colored optical fiber strands. Furthermore, the cable core 5 is formed by twisting and gathering together five optical fiber units 7. Therefore, the cable core 5 of this embodiment is a collection of 100 colored optical fiber strands, and the finished diameter of the cable core 5 is, for example, 3.2 mmφ.

  Further, on the outer periphery of the cable core 5, a plurality of protective tapes 9 having a narrower width than the peripheral length of the outer periphery of the cable core 5 are used. In this embodiment, five protective tapes 9 having a narrow width are used. Are vertically attached to the longitudinal direction of the cable core 5 by wrapping the edge portions of the respective protective tapes 9 so as to cover the outer periphery of the cable core 5. The protective tape 9 is preferably 3 or more.

  Further, the outer periphery of the plurality of protective tapes 9 is directly covered with a cable sheath 11 made of resin or the like.

  Further, in the cable sheath 11, a lip cord 13 (a tear string) vertically attached in the longitudinal direction of the cable core 5 is embedded at a position facing the cable core 5.

  Further, a pair of tension members 15 are mounted in the cable sheath 11 so as to be shifted by about 90 ° in the circumferential direction of the cable sheath 11 with respect to the pair of lip cords 13 described above. In addition, a protrusion 17 is provided on the surface of the cable sheath 11 so as to protrude outward from the position of the pair of tension members 15. In this embodiment, the outer diameter of the optical fiber cable 1 is 6.50 to 15.80 mmφ.

  With the above configuration, the optical fiber cable 1 of this embodiment has a relatively narrow protective tape 9 with respect to the outer periphery of the cable core 5 without tightening the cable core 5 that is an aggregate of a plurality of optical fibers 3. Since at least three or more sheets are vertically attached while wrapping the edge portions of each other, the whole is wrapped, so that rough winding as in a normal tape attaching method is not required.

  By the way, in the case of normal tape longitudinal attachment, since a single tape is formed into a cylindrical shape, rough winding is essential to maintain this cylindrical state. However, the method of this embodiment does not require rough winding. That is, as described above, the cable core 11 is directly wound on the narrow protective tape 9 that is vertically attached while being wrapped with each other without rough winding, thereby tightening the cable core 5 by tape winding or rough winding. Without it, the entire cable core 5 can be wrapped.

  Next, the manufacturing method of the optical fiber cable of this embodiment will be described by taking the manufacturing method of the optical fiber cable 1 of the embodiment shown in FIG. 1 as an example.

  Referring to FIG. 2, as an optical cable manufacturing apparatus 19 used in this embodiment, a plurality of optical fibers 3 are assembled to form a plurality of optical fiber units 7, and then the plurality of optical fiber units 7 are twisted. A collecting machine 21 for collecting together is provided. The aggregation machine 21 includes an optical fiber delivery device 23 for delivering a plurality of optical fibers 3 and a plurality of unit aggregation machines 25 for assembling the plurality of optical fibers 3 to form an optical fiber unit 7. A twisting device 27 is provided for twisting and gathering the plurality of optical fiber units 7 formed by the plurality of unit gathering machines 25 in one direction or the SZ direction.

  In this embodiment, the optical fiber delivery device 23 is provided with 20 optical fiber delivery bobbins 29 corresponding to each optical fiber unit 7, and the optical fiber 3 is wound around each optical fiber delivery bobbin 29. It is sent to the twisting device 27 of the next process through each unit collecting machine 25. In addition, a total of five unit aggregation machines 25 are provided.

  As the twisting device 27, for example, a twisting control plate (not shown) is provided. The twist control plate is provided with five fiber unit insertion holes (not shown) that can pass through the optical fiber unit 7 concentrically with respect to the center. In order to twist the optical fiber unit 7 by SZ, the twist control plate is configured to rotate repeatedly in the forward and reverse directions, that is, in the clockwise and counterclockwise directions in the delivery direction of the optical fiber unit 7.

  Accordingly, 20 optical fiber delivery bobbins 29 are rotated for each unit, and a colored optical fiber strand having a diameter of, for example, 250 μmφ as the optical fiber 3 passes through each of the five unit assembly units 25 and then becomes each optical fiber unit 7. It is sent out so as to pass through the five optical fiber insertion holes of the twist control plate.

  Note that the 20 optical fibers 3 of each optical fiber unit 7 may be sent directly to each fiber unit insertion hole (not shown) of the twisting device 27 without using the unit assembling machine 25 described above. .

  In the twist control plate, the five optical fiber units 7 are alternately rotated in the forward and reverse directions so as to be SZ twisted, and an assembly, that is, the cable core 5 is manufactured. As another example, the above-described five optical fiber units 7 are twisted in one direction by rotating the twisting control plate in one direction.

  Further, the optical cable manufacturing apparatus 19 uses a plurality of protective tapes 9 that are narrower than the circumference of the outer periphery of the cable core 5 around the cable cores 5 assembled by the aggregation machine 21 described above. In this embodiment, five protective tapes 9 having a small width wrap the edges of the protective tapes 9 so as to cover the outer periphery of the cable cores 5 and vertically attach the protective tapes 9 in the longitudinal direction of the cable cores 5. An attachment device 31 is provided.

  For example, as shown in FIGS. 3 and 4, the protective tape longitudinal attachment device 31 is provided with a tape longitudinal attachment die 33. A cable core insertion hole 35 through which the cable core 5 is inserted is provided in the center of the tape vertical die 33, and five protective tapes 9 are inserted around the cable core insertion hole 35 so that each protective tape is inserted. Five tape insertion holes 37 for guiding the 9 edge portions to wrap are provided.

  Therefore, as shown in FIG. 4, the cable core 5 is sent out so as to pass through the cable core insertion hole 35. At the same time, the five protective tapes 9 are sent out so as to pass through the tape insertion holes 37, so that the edge portions of the five protective tapes 9 are vertically attached to the longitudinal direction of the cable core 5 while wrapping. The outer periphery of the cable core 5 is covered.

  Further, the optical cable manufacturing apparatus 19 includes an optical cable for extruding the optical fiber cable 1 by covering the five protective tapes 9 vertically attached to the outer periphery of the cable core 5 so as to cover the cable sheath resin. An extruder 39 is provided.

  The cable core 5 vertically attached by the five protective tapes 9 having a narrow width is sent out to the die 43 of the extrusion head 41 provided in the optical cable extruder 39. At the same time, the pair of lip cords 13 and the pair of tension members 15 are also sent out to the die 43. The die 43 has a shape in which the cable sheath resin is formed into a substantially cylindrical shape so that the cable sheath 11 is pushed out so as to cover the protective tape 9 vertically attached to the cable core 5.

  In the above state, the resin material of the cable sheath 11 heated and smelted is injected into the optical cable extruder 39 and pushed out from the extrusion head 41 so that the cable sheath 11 covers the outer periphery of the cable core 5. Extruded into a substantially cylindrical shape by pipe extrusion. At this time, the cable core 5, the pair of lip cords 13, and the pair of tension members 15 are fed in accordance with the speed at which the resin material of the cable sheath 11 is pushed out. The optical fiber cable 1 having a cross-sectional shape is manufactured.

  Next, Example 1 of the optical fiber cable 1 of this embodiment and the optical fiber cables of Comparative Examples 1 to 4 were manufactured, and each transmission loss maximum value (dB/km@1.55 μm), impact characteristics, The cable outer diameter was compared. The results are as shown in Table 1.

  The impact characteristics are those obtained by conducting an impact test with a 10 mm impact cylinder having a diameter of 20 mm.

Further, in the optical fiber cables of Example 1 and Comparative Examples 1 to 4, each cable core 5 is formed by mounting 100 cores of colored optical fiber having a diameter of 250 μmφ, as in the above-described embodiment. This is a 100-fiber optical fiber cable in which the finished diameter of the core 5 is about 3.2 mmφ. Comparative Examples 1 to 4 are examples in which a presser winding, a sheath, and a separation member for the lip cord 13 were examined.

  As can be seen from Table 1, in Example 1, the maximum transmission loss was 0.20 dB/km@1.55 μm (hereinafter simply referred to as “dB / km”), and the impact characteristics were also good. The cable outer diameter is 6.50 to 15.80 mmφ.

  The comparative example 1 is different from the first embodiment in that tape lateral winding is performed on the outer periphery of the cable core 5. The result is the same as the first embodiment except that the maximum transmission loss is 2.10 dB / km. There is no problem when the fiber is previously stored in the protective member as in the slot structure or the loose tube structure. However, when the optical fiber 3 is roughly wound around the cable core 5 as in this embodiment, the cable core 5 is tightened. This will cause loss degradation. Therefore, it is clear that Example 1 is superior.

  The comparative example 2 is different from the first embodiment in that the outer periphery of the tape is roughly wound after the tape core is attached to the outer periphery of the cable core 5. The result is the same as in the first embodiment except that the maximum transmission loss is 1.60 dB / km. Even if the tape is vertically attached to the cable core 5 in which the optical fibers 3 are assembled, if the outside is roughly wound, the cable core 5 is tightened for the same reason as in the comparative example 1, which causes loss deterioration. Therefore, it is clear that Example 1 is superior.

  Comparative Example 3 differs from Example 1 in that a narrow tape is vertically attached to the lip cord. The result is almost the same as in Example 1, but the impact characteristics are lost and the lip cord is exposed in some places. Therefore, it is clear that Example 1 is superior.

  The comparative example 4 is different from the first embodiment in that a yarn is mounted as a protective member around the cable core 5. The result is the same as in Example 1 except that the cable outer diameter becomes thicker at 10.0 mm. Therefore, it is clear that Example 1 is superior.

  Next, in the optical fiber cable 1 of this embodiment, in order to investigate the influence of the width dimension and the number of the narrow protective tapes 9, the optical fiber cables 1 of Test Examples 1 to 7 are manufactured, and the respective transmission losses are measured. Maximum values, impact properties, waterproof properties, cable outer diameter, etc. were compared. The results are as shown in Table 2.

  The impact characteristics are those obtained by conducting an impact test with a 10 mm impact cylinder having a diameter of 20 mm.

  Further, the waterproof property is obtained by immersing the optical fiber cable 1 having a length of 40 m (meter) and a water depth of 1 m (meter) for 10 days and then performing a water running test.

Further, in each of the optical fiber cables 1 of Test Examples 1 to 7, as in the above-described embodiment, each cable core 5 has 100 cores of colored optical fiber strands having a diameter of 250 μmφ. This is a 100-fiber optical fiber cable 1 having a finished diameter of about 3.2 mmφ.

  In Test Example 1, the width of the protective tape 9 is 15 mm and the number is one. As a result, the maximum value of the transmission loss is 0.20 dB / km and the outer diameter of the cable is 6.50 mmφ, which is good, but it is difficult to cleanly cover the outer periphery of the cable core 5 with a single protective tape 9. As a result, the lip cord 13 is exposed at portions where the protective tape 9 is broken or wrinkled, and a loss remains in impact characteristics. In addition, there is a problem that the waterproof property is running through the gap between the broken protective tapes 9.

  In Test Example 2, the protective tape 9 has a width of 8 mm and two sheets. As a result, the maximum value of the transmission loss is 0.20 dB / km and the cable outer diameter is 6.50 mmφ, which is good, but it is difficult to cleanly cover the outer periphery of the cable core 5 with the two protective tapes 9. As a result, the lip cord 13 is exposed at portions where the protective tape 9 is broken or wrinkled, and a loss remains in impact characteristics. In addition, there is a problem that the waterproof property is running through the gap between the broken protective tapes 9.

  In Test Example 3, the protective tape 9 has a width of 7 mm and three sheets. As a result, the maximum transmission loss is 0.20 dB / km, the cable outer diameter is 6.50 mmφ, and the impact characteristics are also good. However, it is difficult to cover the entire cable core 5 cleanly with the three protective tapes 9, and the protective tape 9 is broken or wrinkled in some places. Although the cable core 5 is not exposed at this portion, there is a problem that water is running through the gap of the broken protective tape 9 in the waterproof property.

  In Test Example 4, the protective tape 9 has a width of 6 mm and four sheets. As a result, the maximum transmission loss is 0.20 dB / km, the cable outer diameter is 6.50 mmφ, and the impact characteristics are also good. Since the width dimension of the protective tape 9 is reduced, the protective tape 9 is not broken or wrinkled.

  In Test Example 5, the width of the protective tape 9 is 5 mm and the number of sheets is 5. As a result, the maximum transmission loss is 0.20 dB / km, the outer diameter of the cable is 6.50 mmφ, and the impact characteristics and the waterproof characteristics are good. Since the width dimension of the protective tape 9 is reduced, the protective tape 9 is not broken or wrinkled.

  In Test Example 6, the protective tape 9 has a width of 5 mm and 8 sheets. As a result, the maximum value of transmission loss is 0.20 dB / km, the cable outer diameter is 9.50 mmφ, and the impact characteristics and the waterproof characteristics are good. Since the width dimension of the protective tape 9 is reduced, the protective tape 9 is not broken or wrinkled.

  In Test Example 7, the protective tape 9 has a width of 5 mm and 8 sheets. As a result, the maximum value of transmission loss is 0.20 dB / km, the cable outer diameter is 15.50 mmφ, and the impact characteristics and the waterproof characteristics are good. Since the width dimension of the protective tape 9 is reduced, the protective tape 9 is not broken or wrinkled.

  Considering the above Example 1 and Comparative Examples 1 to 4 and Test Examples 1 to 7 as a whole, when the cable core 5 is tightened with tape or coarse winding, a significant increase in transmission loss occurs. If the cable core 5 is completely separated from the cable sheath 11 by the protective tape 9, the impact characteristics are good. Moreover, the mounting of a protective member such as a yarn is not suitable for reducing the cable diameter. Further, by using the protective tape 9 as narrow as possible, the protective tape 9 can be folded or wrinkled by vertically attaching it to the cable core 5 while wrapping the edge portions of the plurality of thin protective tapes 9 together. The cable core 5 can be wound around without sagging, and good cable characteristics can be obtained.

  Moreover, even if there is water leakage in the waterproof property, the protective tape 9 is preferably 3 or more in terms of good impact properties, and is preferably about 8 in terms of good waterproof properties and impact properties. .

  From the above, using a plurality of narrow protective tapes 9, the edges of the protective tape 9 are vertically attached to the outer periphery of the cable core 5 while wrapping each other, and on the plurality of protective tapes 9 By adopting a structure in which the cable sheath 11 is directly applied without rough winding, good transmission characteristics can be obtained, impact resistance characteristics can be improved, and a small-diameter high-density cable can be realized. Further, it is possible to prevent the optical fiber 3 from being caught in a crack generated on the inner surface of the cable sheath 11 or a gap between the cracks. Therefore, since the multi-fiber optical fiber 3 can be manufactured as the optical fiber cable 1 having a small outer diameter, it is possible to save resources in terms of construction and physical distribution.

It is sectional drawing of the optical fiber cable of embodiment of this invention. It is a schematic explanatory drawing which shows the manufacturing method of the optical fiber cable of embodiment of this invention. It is a top view of the die for tape vertical attachment in a protection tape vertical attachment apparatus. It is a perspective view explaining the state which vertically attaches several protective tapes to the outer periphery of a cable core with the tape die for vertical attachment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical fiber cable 3 Optical fiber 5 Cable core 7 Optical fiber unit 9 Protective tape 11 Cable sheath 13 Lip cord 15 Tension member 19 Optical cable manufacturing apparatus 21 Collecting machine 25 Unit collecting machine 27 Twisting apparatus 31 Protective tape vertical attachment apparatus 33 Vertical tape Die for attachment 35 Cable core insertion hole 37 Tape insertion hole 39 Optical cable extruder

Claims (5)

A cable core that aggregates multiple optical fibers;
A plurality of protective tapes that are narrower than the outer peripheral length of the cable core, and a plurality of the protective tapes are vertically attached in the longitudinal direction of the cable core by wrapping the edge of each protective tape so as to cover the outer periphery of the cable core. A piece of protective tape,
A cable sheath directly covering the outer periphery of the plurality of protective tapes;
An optical fiber cable comprising:   The optical fiber cable according to claim 1, wherein the protective tape is three or more.   3. The cable core according to claim 1, wherein the cable core includes a plurality of optical fiber units in which a plurality of optical fibers are assembled into a unit, and the plurality of optical fiber units are twisted together. Fiber optic cable.   A plurality of optical fibers are aggregated to form a cable core, and a plurality of protective tapes having a width smaller than the outer peripheral length of the cable core are used to cover the outer periphery of the cable core so as to cover the edge portion of each protective tape. An optical fiber cable is manufactured by wrapping a cable in the longitudinal direction of the cable core and manufacturing the optical fiber cable by directly covering the outer periphery of the plurality of protective tapes attached vertically with a cable sheath. Method.   5. The optical fiber cable according to claim 4, wherein the cable core is formed by gathering a plurality of optical fibers into a unit to form an optical fiber unit, and then twisting and gathering the plurality of optical fiber units. Manufacturing method.

Images