JP2005234361A - Optical fiber unit, optical fiber cable using the same, and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve productivity of an optical cable and ability in intermediate after-branching thereof, and also to unitize optical fibers to be able to prevent an increase in loss at the time of intermediate after-branching. <P>SOLUTION: An optical fiber unit 1 is constituted by converging two or more optical fibers 3 to be held in an optical fiber cable. As to the two or more optical fibers 3, the center of each optical fiber 3 is arranged on almost the same circumference in a plane perpendicular to the longitudinal direction of the optical fiber 3, and also an interval is provided between outer peripheral faces of each optical fiber 3 in the line connecting the centers of each optical fiber adjacent to each other on the circumference, and the convergence center part of the two or more optical fibers 3 and a part of the side of each optical fiber 3 are fixed by bridging 19. Therefore, the optical fibers 3 are prevented from coming loose at the time of intermediate after-branching, discrimination of the fibers 3 is improved, workability of taking the fibers 3 out is improved, and increase in loss at the time of intermediate after-branching is prevented. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an optical fiber unit, an optical fiber cable using the optical fiber unit, and a method for manufacturing the optical fiber unit. In particular, in the structure of a single-core slot optical cable, the optical cable manufacturability and intermediate post-branching are improved. The present invention relates to an optical fiber unit in which optical fibers are unitized so that an increase in loss can be prevented, an optical fiber cable using the optical fiber unit, and a manufacturing method thereof.

  An optical fiber cable (hereinafter simply referred to as an “optical cable”) configured by housing a plurality of optical fibers of 0.25 mmφ is to improve the connection workability with a plurality of optical fibers of the downstream optical cable. In addition, a plurality of optical fibers housed in the optical cable are bundled in advance and unitized.

  Referring to FIGS. 10A, 10B, and 11, conventionally, in order to form a plurality of optical fibers 101 as a unit into an optical fiber unit 103, a plurality of optical fibers 101 are vertically attached. The mainstream is a bundle of bunching yarns 105 bound to the outer periphery. For example, when the colored optical fiber 101 is accommodated in a single groove in the slot groove 111 of the slot 109 of the optical cable 107 as shown in FIG. 11, four optical fibers 101 (for example, the outer diameter is 0.5 mm). It is general to use a structure in which a plurality of units are accommodated in one slot groove 111 by roughly winding an optical fiber core wire) with a bunching yarn 105 as an optical fiber unit 103.

  As the optical cable 107, for example, as shown in FIG. 11, there is an aerial round type 32-core optical cable, and four slot grooves 111 formed by SZ twist are formed on the outer periphery of a slot 109 having a tension member 113 at the center. One or a plurality of the optical fiber units 103 (two optical fiber units 103 in FIG. 11) are accommodated in each slot groove 111, and a presser winding 115 made of a nonwoven fabric or the like is wound around the outer periphery of the slot 109. Then, a cable sheath 117 made of polyethylene resin or the like is applied to the outer periphery of the presser winding 115 (see, for example, Patent Document 1 and Patent Document 2).

Referring to FIG. 12, as a conventional optical fiber unit 119, four optical fibers 101 arranged in parallel are fixed by a resin fixing material 121, and an optical fiber tape core defined by JIS C 6838 is used. It is the form of a line.
Japanese Patent No. 3423192 JP-A-9-152529

  By the way, in the conventional optical fiber unit 103, when cross-binding with the bunching yarn 105, it is necessary to reduce the coarse winding tension as much as possible so as not to increase the loss by tightening the optical fiber 101. However, the optical fiber 101 is cheap and has a problem in that it is difficult to distinguish from other optical fiber units 103 housed in the same slot groove 111.

  In addition, when the target optical fiber 101 is taken out at the time of branching after the middle, if the optical fiber 101 is broken, there is a problem that the other optical fiber 101 is liable to be twilled.

  Further, when the bunching yarn 105 is cross-wound, there is a problem in that the yarn is easily cut and the linear velocity is not generated, so that the productivity is poor.

  The optical fiber unit 119 shown in FIG. 12 is suitable for a slot type multi-core optical cable having 100 to 300 cores, but is not very suitable for a slot type multi-core optical cable having less than 100 cores.

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

The optical fiber unit of the present invention is an optical fiber unit formed by converging a plurality of optical fibers housed in an optical fiber cable.
The plurality of optical fibers are arranged on substantially the same circumference in a plane orthogonal to the longitudinal direction of the optical fibers, and the centers of the optical fibers adjacent to each other on the circumference are connected. An interval is provided between the outer peripheral surfaces of the optical fibers on the line, and the converging central portion of the plurality of optical fibers and a part of the side surfaces of the optical fibers are fixed with a fixing material provided in a substantially circular shape on the surface. With
When the diameter of the fixing material is Dc, the diameter of the circumference in which the plurality of optical fibers are arranged is Do, and the center radius of each optical fiber is r,
Do-2r <Dc <Do + 2r
It is characterized by being configured to satisfy the above conditions.

  In the optical fiber unit of the present invention, it is preferable that in the optical fiber unit, the arrangement state of the plurality of optical fibers satisfies a condition of Do> 2√2 · r.

  Moreover, it is preferable that the optical fiber unit of this invention forms the said fixing material continuously in the longitudinal direction of an optical fiber in the said optical fiber unit.

  Moreover, it is preferable that the optical fiber unit of this invention forms the said fixing material intermittently in the longitudinal direction of an optical fiber in the said optical fiber unit.

  In the optical fiber unit of the present invention, it is preferable that the fixing material is colored in the optical fiber unit.

An optical fiber cable according to the present invention comprises an optical fiber unit by converging a plurality of optical fibers and a cable core containing one or a plurality of the optical fiber units, and a cable sheath covering an outer peripheral portion of the cable core; , And
The optical fiber unit has the plurality of optical fibers arranged on substantially the same circumference in a plane orthogonal to the longitudinal direction of the optical fibers, and adjacent to each other on the circumference. An interval is provided between the outer peripheral surfaces of the optical fibers on the line connecting the centers of the optical fibers, and the converging central portion of the plurality of optical fibers and a part of the side surfaces of the optical fibers are provided in a substantially circular shape on the surface. And fixing with a fixing material,
When the diameter of the fixing material is Dc, the diameter of the circumference in which the plurality of optical fibers are arranged is Do, and the center radius of each optical fiber is r,
Do-2r <Dc <Do + 2r
It is characterized by being configured to satisfy the above conditions.

  In the optical fiber cable of the present invention, it is preferable that in the optical fiber cable, the arrangement state of the plurality of optical fibers satisfies a condition of Do> 2√2 · r.

  In the optical fiber cable of the present invention, it is preferable that the fixing material is continuously applied in a longitudinal direction of the optical fiber in the optical fiber cable.

  In the optical fiber cable of the present invention, it is preferable that the fixing material is intermittently applied in the longitudinal direction of the optical fiber in the optical fiber cable.

  In the optical fiber cable of the present invention, it is preferable that the fixing material is colored in the optical fiber cable.

  In the optical fiber cable of the present invention, in the optical fiber cable, the cable core includes a slot having a tensile body at a central portion and a slot groove at an outer peripheral portion, and one or a plurality of the plurality of the above-described ones are provided in the slot groove It is preferable to store the optical fiber unit.

Further, the optical fiber cable of the present invention, in the optical fiber cable, the cable core includes one or a plurality of the optical fiber units, and an interposed member vertically attached around the optical fiber unit,
It is preferable that a pair of strength members arranged at opposing positions sandwiching the center of the cable sheath is vertically attached to the cable sheath.

In the method for manufacturing an optical fiber cable according to the present invention, a plurality of optical fibers are arranged on substantially the same circumference in the plane orthogonal to the longitudinal direction of the optical fibers, and on the circumference. An interval is provided between the outer peripheral surfaces of the optical fibers on a line connecting the centers of the optical fibers adjacent to each other, and the converging central portion of the plurality of optical fibers and a part of the side surfaces of the optical fibers are substantially at the surface. While fixing with a circular shaped fixing material,
When the diameter of the fixing material is Dc, the diameter of the circumference in which the plurality of optical fibers are arranged is Do, and the center radius of each optical fiber is r,
Do-2r <Dc <Do + 2r
Supplying one or a plurality of optical fiber units converged so as to satisfy the above conditions and supplying them to the extrusion head;
Extruding a resin for a cable sheath to the extrusion head;
Extruding the outer periphery of the one or more optical fiber units so as to cover with a cable sheath;
It is characterized by comprising.

In the method for manufacturing an optical fiber cable according to the present invention, a plurality of optical fibers are arranged on substantially the same circumference in the plane orthogonal to the longitudinal direction of the optical fibers, and on the circumference. An interval is provided between the outer peripheral surfaces of the optical fibers on a line connecting the centers of the optical fibers adjacent to each other, and the converging central portion of the plurality of optical fibers and a part of the side surfaces of the optical fibers are substantially at the surface. While fixing with a circular shaped fixing material,
When the diameter of the fixing material is Dc, the diameter of the circumference in which the plurality of optical fibers are arranged is Do, and the center radius of each optical fiber is r,
Do-2r <Dc <Do + 2r
A process of running and supplying an optical fiber unit converged so as to satisfy the above-mentioned conditions; and
Storing one or a plurality of the optical fiber units in the slot groove of a slot having a tensile body at the center and a slot groove at the outer periphery, and forming a cable core;
Supplying the extrusion head by running the cable core;
Extruding a resin for a cable sheath to the extrusion head;
Extruding to cover the outer periphery of the cable core with a cable sheath;
It is characterized by comprising.

  As will be understood from the means for solving the above problems, according to the present invention, when the optical fiber unit focuses a plurality of optical fibers, a treatment such as winding with a bind yarn as in the prior art is performed. Even if it does not give, it can be integrated by a fixing material (center interposing material). In addition, since the centers of the plurality of optical fibers are arranged on substantially the same circumference and a gap is formed between the outer peripheral surfaces of the adjacent optical fibers, the circumference of the plurality of optical fibers is reduced. As a result, the fixing material on the center side and the outer side are not separated, so that integration can be made more reliably.

  Further, since the optical fibers adjacent to each other on the circumference are narrowest on the line connecting the centers of the respective optical fibers, one optical fiber can be easily separated by a weak force on this line, and the take-out property is improved. Can be improved.

  In addition, since the range of the diameter Dc of the fixing material is set to Do-2r <Dc <Do + 2r, it is possible to reliably prevent the optical fiber from being scattered, to improve the discriminability even with respect to the tracer color optical fiber, and to take out the optical fiber Workability can be improved.

  Furthermore, the optical fiber unit can be easily identified by coloring the fixing material.

  As described above, the optical fiber cable using this optical fiber unit ensures the prevention of optical fiber breakage during the operation of intermediate post-branching, and provides a tracer-colored optical fiber, similar to the effect of the optical fiber unit described above. In contrast, the discriminability can be improved and the workability of taking out the optical fiber can be improved. Further, it is possible to prevent an increase in loss at the time of intermediate post branching.

  For the reasons described above, the manufacturability of the optical fiber cable using this optical fiber unit can be improved.

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

  Referring to FIGS. 1A to 1D, an optical fiber unit 1 according to this embodiment is a unit in which a plurality of optical fibers 3 are converged and is shown in FIG. As described above, these are accommodated in various optical fiber cables 5 (hereinafter simply referred to as “optical cables”). In this embodiment, the optical fiber 3 is an optical fiber 7 (for example, an outer diameter of 0.25 mm) or an optical fiber core 13 (for example, an outer diameter of 0.9 mm) defined by JIS. It is included.

  When the optical fiber 3 is an optical fiber 7, as shown in FIG. 1 (C), a coating resin such as a UV resin is used as a coating material on the outer periphery of the optical bare fiber 9 of 125 μm quartz glass. 11 and having a diameter of 250 μmφ.

  When the optical fiber 3 is an optical fiber core wire 13, as shown in FIG. 1D, 0.4 mmφ is formed as the first coating layer 15 on the outer periphery of the optical bare fiber 9 of 125 μmφ quartz glass. The outer periphery of the silicon resin is coated with a polyamide resin as the second coating layer 17 so that the diameter is 0.9 mmφ.

  2 to 4, the optical fiber unit 1 according to this embodiment includes a surface in which a plurality of color-coded (four in this case) optical fibers 3 are orthogonal to the longitudinal direction of the optical fiber 3. In FIG. 5, the centers of the optical fibers 3 are vertically focused so as to be arranged on, for example, substantially the same circumference of the unit core diameter Do. Furthermore, the focusing central portion of the four optical fibers 3 and a part of the side surface of each optical fiber 3 are continuously fixed in the longitudinal direction of the optical fiber 3 with, for example, a thermoplastic resin as a fixing material 19 (center interposing material). It is unitized by being done. In addition, the said fixing material 19 can attach the four optical fibers 3 vertically by using a low shrink material as a thermoplastic resin.

  The above-mentioned focusing central portion indicates the range of the fixing material 19 in the state of FIG. 3. In this state, the fixing material 19 is simply in contact with the outer peripheral surface of the plurality of optical fibers 3. 19 is not in a fixed state.

  Further, in order to prevent the low shrink material as the fixing material 19 from being separated into the inside (center side) and the outside in the unit radial direction, the unit core diameter Do of the four optical fibers 3 is Do> 2√. 2 · r. Here, r is the center radius of the optical fiber 3. That is, when the number of the optical fibers 3 of the optical fiber unit 1 is four, a gap is generated between the outer peripheral surfaces of the adjacent optical fibers 3 under the condition of Do> 2√2 · r. Therefore, the center and outer low shrink materials are not separated from the circumference of the unit core diameter Do.

  In addition, when the number of the optical fibers 3 of the optical fiber unit 1 is another number, the above conditions are different. For example, when there are six optical fibers 3, Do> 2√3 · r. In any case, this embodiment is characterized in that the optical fiber unit 1 composed of a plurality of optical fibers 3 is arranged so that a gap is formed between the outer peripheral surfaces of the optical fibers 3 adjacent to each other. is there.

  Furthermore, if the diameter Dc of the center interposing material (fixing material 19) made of low shrink resin is too small, the optical fiber core wire 13 will be scattered, while if the diameter Dc is too large, the optical fiber unit will be broken. It becomes difficult to take out one of the cores, and it becomes difficult to identify the optical fiber 3 of the tracer color.

  Therefore, this embodiment is characterized in that the range of the diameter Dc of the fixing member 19 (center interposing member) is Do-2r <Dc <Do + 2r. That is, Do-2r is the diameter of the inscribed circle of the four optical fibers 3 as shown in FIG. A larger range (not including the minimum diameter). On the other hand, Do + 2r is the diameter of the circumscribed circle of the four optical fibers 3 where the diameter Dc of the fixing material 19 (center intermediary material) is smaller than the maximum diameter of the fixing material 19 as shown in FIG. (Not including the maximum diameter).

  From the above, the optical fiber unit 1 composed of the four-fiber optical fiber 3 is formed by the four-fiber optical fiber 3 using the above-described fixing material 19 (central It is in the state integrated by the material. At this time, since the unit core diameter Do of the four optical fibers 3 is set to Do> 2√2 · r in relation to the center radius r of the optical fiber 3, the fixing member 19 is located on the inner side (center side) in the unit radial direction. ) And the outside, it is more reliably integrated. However, since the distance between the outer peripheral surfaces of the adjacent optical fibers 3 is the narrowest distance on the line connecting the centers of the optical fibers, one optical fiber 3 can be easily removed from the optical fiber unit 1 on this line by a weak force. Can be separated.

  In addition, since the range of the diameter Dc of the fixing material 19 (center interposing material) is Do-2r <Dc <Do + 2r, the fixing material 19 on the inner side (center side) of the circumference of the unit core diameter Do is surely 4 The optical fibers 3 can be integrated in close contact with each other. On the other hand, since the fixing member 19 outside the circumference of the unit core diameter Do does not cover each optical fiber 3, it is avoided that each optical fiber 3 cannot be identified.

  Therefore, the optical fiber unit 1 of this embodiment ensures the prevention of the optical fiber 3 from being scattered, improves the discriminability with respect to the tracer-color optical fiber 3, and improves the workability of taking out the optical fiber 3. Can do.

  In addition, although the fixing material 19 (center intermediary material) of said embodiment is continuously provided in the longitudinal direction of the optical fiber unit 1 in FIG. 1 (A), it is shown by FIG. 5 (A). Even if it is provided intermittently in the longitudinal direction of the optical fiber unit 1 as shown in FIG. Further, the optical fiber unit 1 is applied even when a plurality of optical fibers 3 are twisted and converged in one direction as shown in FIG. In this case, by using a thermoplastic resin of a low shrink material as the fixing member 19, the twist pitch of the optical fiber 3 can be increased. Although not shown in the figure, the optical fiber unit 1 shown in FIG. 5B is also applicable even if the fixing material 19 is provided intermittently in the longitudinal direction of the optical fiber unit 1.

  Next, the optical cable 5 of this embodiment will be described with reference to the drawings.

  Referring to FIG. 6, the optical cable 5 according to the embodiment of the present invention is provided with four slot grooves 25 formed in an SZ twist on the outer periphery of a slot 23 having a tension member 21 as a strength member at the center. In each slot groove 25, one or a plurality of the optical fiber units 1 are housed, and in this embodiment, two optical fiber units 1 are housed. Further, a presser winding 27 made of a nonwoven fabric or the like is wound around the outer periphery of the slot 23, and these constitute a cable core 29 as a whole.

  A cable sheath 31 (jacket) covers the outer periphery of the cable core 29. The cable sheath 31 is made of PE (polyethylene) or PVC (polyvinyl chloride).

  Referring to FIG. 7, as an optical cable 33 according to another embodiment of the present invention, a structure in which one or a plurality of the optical fiber units 1 described above, and five optical fiber units 1 in this embodiment are mounted. It has become. That is, the interposition member 35 is vertically attached so as to protect the space between and around the five optical fiber units 1, and these constitute the cable core 37 as a whole. The interposition member 35 is made of, for example, PP yarn (polypropylene yarn). A cable sheath 39 (outer jacket) is provided so as to cover the outer periphery of the cable core 37, and the cable sheath 39 has a position where two strength members 41 are opposed to the outside of the cable core 37. Built in parallel to the stretching direction. The cable sheath 39 is made of PE (polyethylene) or PVC (polyvinyl chloride).

  Next, an optical cable 5 containing the optical fiber unit 1 of this embodiment was manufactured as a prototype, and transmission characteristics and workability during intermediate post-branching were verified.

  The optical fiber unit 1 has a structure in which four optical fiber cores 13 of 0.5 mm are vertically attached as the optical fiber 3 and are integrated with a polypropylene resin containing a filler as a fixing member 19 (center interposing member). The unit core diameter Do of the four optical fibers 3 is 0.9 mm (Do = 0.9 mm), and the diameter Dc of the fixing member 19 (center interposing material) is 1.0 mm (Dc = 1.0 mm). is there.

  The prototype optical cable 5 is a 40-fiber slot type optical cable in which two optical fiber units 1 are accommodated in each slot groove 25 as shown in FIG. The slot 23 has a steel wire having a diameter of 2 mm as the tension member 21 at the center, and has five SZ slot grooves 25 on the outer peripheral portion.

  As a result of the evaluation of the loss temperature characteristics of −30 ° C. to + 70 ° C. × 3 cycles for the example cable 5 manufactured as a prototype as described above, this example cable 5 has an initial loss of 0 at a measurement wavelength of 1.55 μm. .20 dB / km, the maximum during the temperature characteristic test was 0.23 dB / km, and good loss characteristics were exhibited.

  Also, an optical cable containing the optical fiber unit having the conventional structure shown in FIG. 10 was manufactured as a comparative example cable, and an intermediate post-branching experiment was conducted on two types of optical cables, the comparative example cable and the above-described example cable 5. . The comparative example cable has the same structure as the example cable 5 except for the configuration of the optical fiber unit.

In this intermediate post-branching experiment, as shown in FIG. 8, the work until the cable sheath 31 was peeled off and the internal optical fiber 3 was taken out was performed, and workability was confirmed. In addition, the above workability shows the visibility and the take-out property of the optical fiber, and the single optical fiber 3 can be easily taken out from the four-fiber optical fiber unit taken out from the slot groove 25 of each cable at the time of intermediate post branching. Judgment was made based on whether or not Furthermore, the loss fluctuation (@ 1.55 μm) of the optical fiber 3 during the intermediate post branching operation was monitored at a sampling period of 10 msec. The results are shown in Table 1. In addition, in the evaluation of the above-described visibility and take-out property, ◎ indicates “excellent” and Δ indicates “poor”.

  As can be seen from Table 1, in the example cable 5, the visibility of the optical fiber 3 at the time of rear branching was excellent, and loss fluctuation of the optical fiber 3 at the time of work did not occur. On the other hand, in the comparative example cable, the visibility and the take-out property of the optical fiber are inferior to those of the example cable 5.

  From the above results, it can be seen that the structure of the example cable 5 is an optical cable with excellent transmission characteristics and superior workability than the structure of the conventional comparative cable.

  Next, the manufacturing method of the slot type optical cable 5 shown in FIG. 6 will be described as an example of the manufacturing method of the optical cable of this embodiment.

  Referring to FIG. 9, as an optical cable manufacturing apparatus 43 used in this embodiment, a slot sending apparatus 45 for sending a slot 23 and a plurality of optical fiber units 1 of the above-described embodiment are sent. A unit sending device 47, a twisting device 49 for storing a plurality of optical fiber units 1 in the slot groove 25 of the slot 23, and a slot 23 in which the optical fiber unit 1 is stored by the twisting device 49. A presser winding device 51 for winding up the presser winding 27 and an extruder 53 for extruding the optical cable 5 by covering the cable winding resin on the presser winding 27 and covering the cable sheath resin. Has been.

  In this embodiment, the slot delivery device 45 is provided with one slot delivery bobbin 55, and the slot 23 provided with the tension member 21 is wound around the center. In this embodiment, the slot 23 is provided with four SZ twisted slot grooves 25 as shown in FIG.

  Each unit delivery device 47 is provided with 10 unit delivery bobbins 57, and each unit delivery bobbin 57 is wound with the optical fiber unit 1 of the above-described embodiment, and sent to the twisting device 49 of the next process. It is.

  As the twisting device 49, for example, a twisting control plate (not shown) is provided. The twist control plate is provided with one slot insertion hole that can pass through the slot 23 in the center, and five unit insertion holes that can pass through the optical fiber unit 1 around the slot insertion hole. Yes. The twisting control plate is repeatedly rotated in the forward and reverse directions, that is, in the clockwise and counterclockwise directions toward the feeding direction of the slot 23 in order to twist the optical fiber unit 1 in the slot groove 25 and SZ. It is configured as follows.

  The slot delivery bobbin 55 is rotated so that the slot 23 passes through the slot insertion hole of the twisting control plate, and a total of ten optical fiber units 1 are connected to the five twisting control plates. The two optical fiber units 1 are sent out to the unit insertion holes, that is, to the respective unit insertion holes.

  In the twisting device 49, the twisting control plates are alternately rotated in the forward and reverse directions so that the two optical fiber units 1 are inserted into the slot grooves 25 of the SZ twist of the slot 23, respectively.

  In the presser winding device 51, the presser winding 27 delivered from the presser winding delivery bobbin 59 is wound around the slot 23 in a state where the two optical fiber units 1 are inserted into the respective slot grooves 25, and the cable core. 29 is formed.

  The cable core 29 is sent to a cable sheath resin die 63 of an extrusion head 61 provided in the extruder 53. The cable sheath resin die 63 is formed in a substantially cylindrical shape so that, for example, polyethylene resin as a cable sheath resin is pushed out so as to wrap around the presser winding 27 wound around the slot 23 as the cable sheath 31. It becomes the shape to do.

  In the above state, for example, polyethylene resin as a resin material of the cable sheath 31 heated and smelted is injected into the extruder 53 and extruded from the extrusion head 61, so that the polyethylene resin of the cable sheath 31 is outside the cable core 29. It is extruded into a substantially cylindrical shape by pipe extrusion so as to cover the periphery. At this time, the cable core 29 is fed in accordance with the speed at which the polyethylene resin as the cable sheath resin is pushed out, so that the optical cable 5 having the cross-sectional shape shown in FIG.

  That is, the manufacturing method of the optical cable 5 includes the following steps.

(1) The process of running the optical fiber unit 1 formed by converging the four optical fibers 3 and integrating them with the fixing member 19 (center intermediary material) and sending them to the twisting device 49 (2) The optical fiber unit 1 is twisted with a twisting control plate of the twisting device 49 so as to be inserted into a predetermined position of the slot groove 25 of the slot 23, and a cable core 29 is formed by winding a presser winding 27 around the outer periphery of the slot 23. (3) A step of feeding the cable core 29 into which the optical fiber unit 1 is inserted and feeding it to the die 63 of the extrusion head 61. (4) A polyethylene resin as a cable sheath resin to the die 63 of the extrusion head 61. (5) Extruding to provide a cable sheath 31 so as to cover the outer periphery of the cable core 29 Here, a supply step of one slot 23 and ten optical fiber units 1, a press core 27 is wound around the outer periphery of the slot 23 to form a cable core 29, and a supply step of the cable core 29, The process of extruding the resin for cable sheath from the die 63 of the extrusion head 61 is simultaneously performed in a continuous process, and the optical cable 5 is quickly manufactured.

  From the above, in the optical fiber unit 1 of this embodiment, a plurality of the optical fibers 3 are converged and integrated with the fixing material 19 (center interposing material). The optical fiber unit 1 can be easily converged without using a body. By housing the optical fiber unit 1 in the optical cable 5, for example, the manufacturability of the optical cable 5 can be improved. Furthermore, for the reasons described above, there is no striated body such as a bunching yarn as in the prior art, so that the workability of the intermediate post branching of the optical cable 5 can be improved.

  Further, the optical fiber unit 1 according to the embodiment of the present invention is particularly suitable for a slot type small-core optical cable having less than 100 cores.

(A) is a perspective view of an optical fiber unit according to an embodiment of the present invention, (B) is a sectional view showing a longitudinal sectional shape of (A), and (C) is a light as an optical fiber of (A). It is sectional drawing of a fiber strand, (D) is sectional drawing of the optical fiber core wire as an optical fiber of (A). It is an enlarged view of Drawing 1 (B), and is a sectional view showing the relation between an optical fiber and a fixing material. It is sectional drawing which shows the state of the fixed material minimum diameter in FIG. It is sectional drawing which shows the state of the fixed material largest diameter in FIG. (A) is a perspective view of an optical fiber unit according to another embodiment of the present invention, and (B) is a perspective view of an optical fiber unit according to another embodiment. It is sectional drawing of the slot type optical cable of embodiment of this invention. It is sectional drawing of the center tube type | mold optical cable of embodiment of this invention. It is a schematic explanatory drawing at the time of intermediate post branching of the slot type optical cable. It is a schematic explanatory drawing of the manufacturing method of the optical cable of embodiment of this invention. (A) is a perspective view of a conventional optical fiber unit, and (B) is a longitudinal sectional view of (A). It is sectional drawing of the conventional slot type optical cable. It is sectional drawing of the other conventional optical fiber unit.

Explanation of symbols

1 Optical fiber unit 3 Optical fiber 5 Optical cable (optical fiber cable)
7 Optical fiber strand 13 Optical fiber core wire 19 Fixing material (centering material)
21 Tension member (strength member)
23 Slot 25 Slot groove 27 Press winding 29 Cable core 31 Cable sheath 33 Optical cable 35 Interposing member 37 Cable core 39 Cable sheath 41 Strength member 43 Optical cable manufacturing device 49 Twisting device 51 Press winding device 53 Extruder 61 Extrusion head 63 Dies

Claims (14)

In an optical fiber unit formed by focusing a plurality of optical fibers housed in an optical fiber cable,
The plurality of optical fibers are arranged on substantially the same circumference in a plane orthogonal to the longitudinal direction of the optical fibers, and the centers of the optical fibers adjacent to each other on the circumference are connected. An interval is provided between the outer peripheral surfaces of the optical fibers on the line, and the converging central portion of the plurality of optical fibers and a part of the side surfaces of the optical fibers are fixed with a fixing material provided in a substantially circular shape on the surface. With
When the diameter of the fixing material is Dc, the diameter of the circumference in which the plurality of optical fibers are arranged is Do, and the center radius of each optical fiber is r,
Do-2r <Dc <Do + 2r
An optical fiber unit configured to satisfy the above conditions.   2. The optical fiber unit according to claim 1, wherein an arrangement state of the plurality of optical fibers satisfies a condition of Do> 2√2 · r.   3. The optical fiber unit according to claim 1, wherein the fixing material is continuously applied in a longitudinal direction of the optical fiber.   The optical fiber unit according to claim 1, wherein the fixing material is intermittently applied in a longitudinal direction of the optical fiber.   The optical fiber unit according to claim 1, wherein the fixing material is colored. The optical fiber unit is configured by converging a plurality of optical fibers and includes a cable core containing one or a plurality of the optical fiber units, and a cable sheath covering the outer periphery of the cable core,
The optical fiber unit has the plurality of optical fibers arranged on substantially the same circumference in a plane orthogonal to the longitudinal direction of the optical fibers, and adjacent to each other on the circumference. An interval is provided between the outer peripheral surfaces of the optical fibers on the line connecting the centers of the optical fibers, and the converging central portion of the plurality of optical fibers and a part of the side surfaces of the optical fibers are provided in a substantially circular shape on the surface. And fixing with a fixing material,
When the diameter of the fixing material is Dc, the diameter of the circumference in which the plurality of optical fibers are arranged is Do, and the center radius of each optical fiber is r,
Do-2r <Dc <Do + 2r
An optical fiber cable characterized by being configured to satisfy the above conditions.   The optical fiber cable according to claim 6, wherein an arrangement state of the plurality of optical fibers satisfies a condition of Do> 2√2 · r.   The optical fiber cable according to claim 6 or 7, wherein the fixing material is continuously applied in a longitudinal direction of the optical fiber.   The optical fiber cable according to claim 6 or 7, wherein the fixing material is intermittently applied in a longitudinal direction of the optical fiber.   The optical fiber cable according to claim 6, wherein the fixing material is colored.   The cable core includes a slot having a tensile body at a central portion and a slot groove at an outer peripheral portion, and one or a plurality of the optical fiber units are accommodated in the slot groove. The optical fiber cable in any one of -10. The cable core includes one or a plurality of the optical fiber units and an interposition member vertically attached around the optical fiber unit,
The optical fiber cable according to any one of claims 6 to 10, wherein a pair of strength members arranged at opposing positions sandwiching the center of the cable sheath are vertically attached to the cable sheath. A plurality of optical fibers are arranged on a line that connects the centers of optical fibers adjacent to each other on the circumference, with the centers of the optical fibers arranged on substantially the same circumference in a plane orthogonal to the longitudinal direction of the optical fibers. And an interval between the outer peripheral surfaces of each optical fiber in the optical fiber, and fixing the central portion of the plurality of optical fibers and a part of the side surface of each optical fiber with a fixing material provided in a substantially circular shape on the surface ,
When the diameter of the fixing material is Dc, the diameter of the circumference in which the plurality of optical fibers are arranged is Do, and the center radius of each optical fiber is r,
Do-2r <Dc <Do + 2r
Supplying one or a plurality of optical fiber units converged so as to satisfy the above conditions and supplying them to the extrusion head;
Extruding a resin for a cable sheath to the extrusion head;
Extruding the outer periphery of the one or more optical fiber units so as to cover with a cable sheath;
An optical fiber cable manufacturing method comprising: A plurality of optical fibers are arranged on a line connecting the centers of optical fibers adjacent to each other on the circumference, with the centers of the optical fibers arranged on substantially the same circumference in a plane orthogonal to the longitudinal direction of the optical fibers. And an interval between the outer peripheral surfaces of each of the optical fibers, and fixing a central portion of the plurality of optical fibers and a part of the side surface of each of the optical fibers with a fixing material provided in a substantially circular shape on the surface. ,
When the diameter of the fixing material is Dc, the diameter of the circumference in which the plurality of optical fibers are arranged is Do, and the center radius of each optical fiber is r,
Do-2r <Dc <Do + 2r
A process of running and supplying an optical fiber unit converged so as to satisfy the above condition; and
Housing one or a plurality of the optical fiber units in the slot groove of a slot having a tensile strength member at the center and a slot groove at the outer periphery; and molding a cable core;
Supplying the extrusion head by running the cable core;
Extruding a resin for a cable sheath to the extrusion head;
Extruding to cover the outer periphery of the cable core with a cable sheath;
An optical fiber cable manufacturing method comprising:

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