JP6345438B2 - Optical cable manufacturing method and manufacturing apparatus - Google Patents

Description

The present invention relates to an optical cable manufacturing method and manufacturing apparatus .

  It is known to manufacture an optical cable by placing an optical fiber ribbon in a slot (grooved spacer) in which a groove is formed. When manufacturing an SZ-type optical cable by placing an optical fiber ribbon in a slot having an SZ groove (a spiral groove whose direction is periodically reversed), a rotating plate called a face plate of an optical fiber assembling machine is used. By rotating the rotating plate in accordance with the circumferential position of the SZ groove while inserting the optical fiber tape core through the opening, the optical fiber tape core is inserted into the slot groove while twisting the optical fiber tape. Is performed. Patent Documents 1 and 2 disclose a rotating plate (a branching plate of Patent Document 1 and a eyeplate of Patent Document 2) that collects optical fiber ribbons in a slot groove.

  On the other hand, an optical cable is known in which the slot is omitted and the diameter is reduced. Patent Document 3 describes an optical cable in which a slot is omitted and a plurality of optical fibers are assembled in a press-wound tape that is brazed into a cylindrical shape. Patent Document 3 also describes that an optical cable is configured by using a plurality of optical fiber units each including a plurality of optical fibers.

Japanese Patent Laid-Open No. 11-72676 JP-A-11-202175 JP 2013-101175 A

  When twisting a plurality of optical fiber units, if the optical fiber unit bundled in a cylindrical shape is inserted into the circular opening of the rotating plate of the collecting machine, the circular opening is rotated when the rotating plate rotates. In some cases, the optical fiber unit may be idle. As a result, when the optical cable is bent, elongation strain or compression strain is likely to be accumulated in the optical fiber (described later).

  An object of the present invention is to prevent the optical fiber unit from idling inside the opening of the rotating plate when the rotating plate of the collecting machine rotates.

A main invention for achieving the above object is a method of manufacturing a slotless optical cable having a plurality of optical fiber units in which a plurality of optical fibers are bundled, and a non-circular opening of a rotating plate of a collective machine The optical fiber unit is inserted, and a plurality of the optical fiber units are twisted while rotating the rotating plate, and the optical fiber unit includes a plurality of optical fiber tapes, The rotating plate has a plurality of non-circular openings that extend long in the same direction, and the rotating plate is rotated while the optical fiber unit is inserted into each of the openings. An optical cable manufacturing method comprising twisting optical fiber units .

  Other characteristics of the present invention will be made clear by the description and drawings described later.

  ADVANTAGE OF THE INVENTION According to this invention, when the rotating plate of an aggregation machine rotates, it can suppress that an optical fiber unit idles inside the opening part of a rotating plate.

FIG. 1 is a cross-sectional view of the optical cable 1. FIG. 2 is an explanatory diagram of the optical fiber unit 2. FIG. 3 is an explanatory diagram of the intermittently fixed type optical fiber tape 3. FIG. 4 is an explanatory diagram of the manufacturing apparatus 10 for the optical cable 1. FIG. 5 is an explanatory diagram of the eyeplate 12 of the reference example. 6A to 6D are explanatory views of a state when the eye plate 12 of the reference example is rotated. FIG. 7 is a graph of the distance between the bending neutral plane of the optical cable 1 and a certain optical fiber 3A. FIG. 8 is an explanatory diagram of the eyeplate 12 of the first embodiment. FIG. 9A to FIG. 9D are explanatory views of a state when the eyeplate 12 of the first embodiment is rotated. FIG. 10 is a graph of the distance between the neutral plane of bending of the optical cable 1 and a certain optical fiber 3A. FIG. 11 is an explanatory diagram of the eyeplate 12 of a modification of the first embodiment. 12A to 12D are explanatory diagrams illustrating a state when the eye plate 12 according to the modified example of the first embodiment is rotated. FIG. 13 is an explanatory diagram of the eyeplate 12 of the second embodiment. FIG. 14 is an explanatory diagram of the eyeplate 12 of a modification of the second embodiment. FIG. 15 is an explanatory diagram of the collective machine 11 according to the third embodiment.

  At least the following matters will be apparent from the description and drawings described below.

A method of manufacturing an optical cable comprising a plurality of optical fiber units in which a plurality of optical fibers are bundled, wherein the optical fiber unit is inserted through a non-circular opening of a rotating plate of a collecting machine, and the rotating plate A method of manufacturing an optical cable in which a plurality of optical fiber units are twisted while rotating is clarified.
According to this manufacturing method, when the rotating plate of the collecting machine rotates, it is possible to prevent the optical fiber unit from spinning around inside the opening of the rotating plate.

  It is desirable that the opening has a straight portion. This makes it difficult for the optical fiber unit to idle in the opening of the rotating plate.

  The optical fiber unit preferably includes a plurality of optical fiber tapes, and the optical fiber unit is inserted into the opening while the surface of any one of the optical fiber tapes is along the straight line portion. This makes it difficult for the optical fiber unit to idle in the opening of the rotating plate.

  The opening is preferably substantially rectangular. Thereby, it becomes possible to sandwich a plurality of laminated optical fiber tapes from the laminating direction at two opposite sides of the opening.

  The opening is preferably elliptical. This makes it difficult for the optical fiber unit to idle in the opening of the rotating plate.

  The rotating plate has a plurality of non-circular openings, and the plurality of optical fiber units are twisted by rotating the rotating plate with the optical fiber units inserted into the openings. It is desirable that This makes it difficult for the optical fiber unit to idle in the opening of the rotating plate.

  A plurality of the rotating plates having the non-circular openings are provided, and another rotating plate having a plurality of openings is provided on the downstream side of the rotating plates having the non-circular openings. And the optical fiber unit inserted through the non-circular opening is inserted into the opening of the other rotating plate, while rotating the rotating plate having the non-circular opening, It is desirable that a plurality of the optical fiber units be twisted by causing the separate rotating plate. This makes it difficult for the optical fiber unit to idle in the opening of the rotating plate.

The area of the opening is S (mm ² ), the number of optical fibers constituting the optical fiber unit is X, and the cross-sectional area Y (mm ² ) of the optical fiber unit is Y = 0.106X + 0.9777. When expressed by an approximate expression, the ratio Y / S of the cross-sectional area Y of the optical fiber unit to the area S of the opening is preferably 0.65 or more and 0.95 or less. This makes it difficult for the optical fiber unit to idle in the opening of the rotating plate.

=== First Embodiment ===
<Reference explanation: Optical cable 1>
FIG. 1 is a cross-sectional view of the optical cable 1. FIG. 2 is an explanatory diagram of the optical fiber unit 2. The optical cable 1 includes a plurality of optical fiber units 2, a press-wound tape 6, and a jacket 7. The plurality of optical fiber units 2 are twisted in one direction or in an SZ type.

  The optical fiber unit 2 is configured by bundling a plurality of optical fibers 3A. The optical fiber unit 2 bundles the plurality of optical fibers 3A with the bundle material 4 so that the plurality of optical fibers 3A do not fall apart. Here, the optical fiber unit 2 is configured by bundling a plurality of intermittently fixed optical fiber tapes 3.

FIG. 3 is an explanatory diagram of the intermittently fixed type optical fiber tape 3. The intermittently fixed optical fiber tape 3 is an optical fiber tape in which connecting portions 3B that connect adjacent optical fibers 3A are intermittently arranged in the longitudinal direction and the width direction of the optical fiber 3A.
The intermittently fixed optical fiber tape 3 is composed of three or more optical fibers 3A (optical fiber core wires) arranged in parallel. A plurality of connecting portions 3B that connect two adjacent optical fibers 3A are intermittently arranged two-dimensionally in the longitudinal direction and the width direction. The connecting portion 3B is a portion that connects the two adjacent optical fibers 3A with, for example, an ultraviolet curable resin or a thermoplastic resin. A region other than the connecting portion 3B between the adjacent two optical fibers 3A is a non-connecting portion. In the unconnected portion, the adjacent two optical fibers 3A are not restrained. Thereby, the optical fiber tape 3 can be rolled and bundled into a cylindrical shape or folded and stored, and the optical fibers 3A can be mounted on the optical cable 1 with high density.

  Note that the plurality of optical fibers 3 </ b> A constituting the optical fiber unit 2 are not limited to those constituted by the intermittently fixed type optical fiber tape 3. For example, it may be composed of a plurality of single-core optical fibers.

The bundle material 4 (see FIG. 2) is a string-like or tape-like member that bundles a plurality of optical fibers 3A. Here, the bundle material 4 is spirally wound around the plurality of optical fibers 3A. The bundle material 4 is colored, and the color of the bundle material 4 is different for each optical fiber unit 2 in the optical cable 1. Thereby, the bundle material 4 functions as an identification member of the optical fiber unit 2. Note that an identification mark (for example, a barcode) may be formed on the bundle material 4.
Here, one bundle material 4 is used for one optical fiber unit 2, but two or more bundle materials 4 may be used. When there are two or more bundle members 4, the winding directions when spirally wound may be opposite to each other, or one may be vertically attached while the other is spirally wound. Moreover, when the bundle material 4 is two or more, you may join the location where the bundle material 4 cross | intersects.

  The presser winding tape 6 (see FIG. 1) is a member that wraps a plurality of optical fiber units 2 inside the outer cover 7. As the presser winding tape 6, a polyimide tape, a polyester tape, a polypropylene tape, a polyethylene tape, or the like is used. In addition, a nonwoven fabric can be used as the presser winding tape 6. In this case, the nonwoven fabric used is a tape formed of polyimide, polyester, polypropylene, polyethylene or the like. In addition, the nonwoven fabric may be a material to which water-absorbing powder or the like is attached and applied, or a surface processed for that purpose. The presser winding tape 6 may be a non-woven fabric bonded with a film such as a polyester film.

The outer jacket 7 is a member that covers the plurality of optical fiber units 2 (and the presser winding tape 6) so as to be accommodated therein. In the outer jacket 7, a tensile body 8 and a tear string 9 are arranged. The tensile body 8 is a member that resists the contraction of the outer cover 7 and suppresses distortion and bending applied to the optical fiber 3 </ b> A due to the contraction of the outer cover 7. The tear string 9 is a member used when tearing the outer jacket 7 of the optical cable 1 in the longitudinal direction when the optical cable 1 is branched.
The outer jacket 7 may not have the strength member 8 and the tear string 9. Further, either one or both of the strength member 8 and the tear string 9 may be absent inside the outer jacket 7. Further, another member may be arranged inside the outer jacket 7.
Here, the number of the optical fiber units 2 accommodated in the jacket 7 is four, but other numbers may be used.

<Reference explanation: Manufacturing apparatus 10 for optical cable 1>
FIG. 4 is an explanatory diagram of the manufacturing apparatus 10 for the optical cable 1.
The collecting machine 11 has a plate 12 (rotary plate), and the optical fiber units 2 are inserted through the openings 13 of the plate 12. When the eye plate 12 rotates, a plurality of optical fiber units 2 are twisted by the collecting die 14. The eyeplate 12 will be described later.

  The plurality of twisted optical fiber units 2 are supplied to the extruder 16. The extruder 16 is supplied with a plurality of optical fiber units 2, a press-wound tape 6, two strength members 8, and two tear strings 9. The extruder 16 coats the resin (sheath 7) while running the plurality of optical fiber units 2 accommodated in the press-wound tape 6 while feeding the tensile body 8 and the tear string 9 from the respective supply sources. . Thereby, the optical cable 1 shown in FIG. 1 is manufactured. The manufactured optical cable 1 is wound around a drum.

<Reference explanation: Eye plate 12 with circular opening 13>
FIG. 5 is an explanatory diagram of the eyeplate 12 of the reference example. The eye plate 12 of the reference example includes a circular opening 13. By inserting the optical fiber unit 2 into the opening 13 and rotating the eye plate 12, a plurality of optical fiber units 2 are twisted.

  6A to 6D are explanatory views of a state when the eye plate 12 of the reference example is rotated. Here, for the sake of explanation, a state in which the optical fiber unit 2 is inserted through only one opening 13 is shown. Also, one specific optical fiber 3A among the plurality of optical fibers 3A of the optical fiber unit 2 is indicated by a black circle.

  When the opening 13 of the eye plate 12 is circular, when the eye plate 12 is rotated, idle rotation occurs between the opening 13 and the optical fiber unit 2. For this reason, even if the eye plate 12 rotates, the optical fiber unit 2 in the opening 13 is not twisted, and for example, the black circle optical fiber 3A is always in the upper left position. As a result, when the eye plate 12 rotates, the distance between the rotation center of the eye plate 12 and the optical fiber 3A changes. For example, the distance between the rotation center of the eye plate 12 in FIG. 6C and the optical fiber 3A is shorter than the distance between the rotation center of the eye plate 12 in FIG. 6A and the optical fiber 3A.

  FIG. 7 is a graph of the distance between the bending neutral plane of the optical cable 1 and a certain optical fiber 3A. A cross-sectional view of the optical cable 1 is drawn on the upper side of the graph. In this cross-sectional view, the position of the target optical fiber 3A is indicated by a black circle. Here, the optical fiber unit 2 is twisted in one direction at a predetermined pitch. The neutral plane of bending is a plane that does not expand and contract when the optical cable 1 is bent. Here, the plane connecting the pair of strength members 8 is assumed to be a neutral plane.

  When the opening 13 of the eyeplate 12 is circular, the distance between the center of the optical cable 1 and the optical fiber 3A changes (see FIGS. 6A to 6D), so the distance between the neutral plane and the optical fiber 3A is It fluctuates toward one side (here, the upper side in the figure) when viewed from the elevation. As a result, when the optical cable 1 is bent, in the optical fiber 3A indicated by a black circle in FIG. 7 in the range of one pitch, the region where the elongation strain is generated becomes longer than the region where the compressive strain is generated. Elongation strain and compression strain do not cancel out, and elongation strain remains (note that the left side of the optical fiber unit 2 is the same as the black circle optical fiber 3A (axisymmetric position from the center of the optical fiber unit 2)). In the lower right optical fiber 3A, the region where the compressive strain occurs is longer than the region where the tensile strain occurs, and the compressive strain remains without canceling out the stretch strain and the compressive strain of the optical fiber 3A). When the distance between the neutral plane and the optical fiber 3A varies toward one side as seen from the neutral plane as in the optical cable 1 of the reference example, at least of the plurality of optical fibers 3A constituting the optical cable 1 The elongation strain remains in any one of the optical fibers 3A. When elongation strain remains in the optical fiber 3A, there also arises a problem that the fracture life of the optical fiber 3A is shortened. This problem is particularly noticeable when the optical cable 1 is wound around a drum.

  Further, as the diameter of the optical fiber core (the diameter of the approximate circle of the optical fiber assembly formed by collecting a plurality of optical fiber units 2) is increased, the distance between the neutral plane and the optical fiber 3A is one side as viewed from the neutral plane. It fluctuates greatly (here, the upper side in the figure). For this reason, when it is going to increase the number of cores of optical fiber 3A of optical cable 1, since the diameter of an optical fiber core becomes large, it becomes disadvantageous.

<Eye plate 12 of the first embodiment>
FIG. 8 is an explanatory diagram of the eyeplate 12 of the first embodiment. The eye plate 12 of the first embodiment includes a substantially square opening 13 as the non-circular opening 13. By inserting the optical fiber unit 2 into the opening 13 and rotating the eye plate 12, a plurality of optical fiber units 2 are twisted.
In addition, the substantially square shape means a shape that becomes a square when the straight portion constituting the side (the straight portion that comes into contact with the optical fiber 3A) is extended, and does not have to be a strict square. A shape with rounded corners such as the opening 13 is also included. Similarly, in the following description, a substantially rectangular shape (or a substantially rectangular shape) means a shape that becomes a rectangle (or a rectangle) when a straight portion constituting a side is extended, and a shape with rounded corners is also included. Shall be included. In the following description, for the sake of simplicity, “abbreviation” is omitted, and for example, “substantially square” is simply described as “square”.

  FIG. 9A to FIG. 9D are explanatory views of a state when the eyeplate 12 of the first embodiment is rotated. Here, as in the description of the reference example, the state where the optical fiber unit 2 is inserted through only one opening 13 is shown. Also, one specific optical fiber 3A among the plurality of optical fibers 3A of the optical fiber unit 2 is indicated by a black circle.

  When the opening 13 of the eye plate 12 is non-circular, when the eye plate 12 is rotated, the optical fiber unit 2 is restrained in the opening 13 and twisted without spinning. As a result, when the eye plate 12 rotates, the distance between the center of rotation of the eye plate 12 and the optical fiber 3A does not change. For example, the distance between the rotation center of the eye plate 12 in FIG. 9C and the optical fiber 3A is substantially the same as the distance between the rotation center of the eye plate 12 in FIG. 9A and the optical fiber 3A.

  FIG. 10 is a graph of the distance between the neutral plane of bending of the optical cable 1 and a certain optical fiber 3A. When the opening portion 13 of the eye plate 12 is non-circular, the distance between the center of rotation of the eye plate 12 and the optical fiber 3A does not change (FIGS. 9A to 9D), so that the center surface fluctuates. As a result, when the optical cable 1 is curved, the elongation strain and the compressive strain of the optical fiber 3A cancel each other within a range of one pitch. That is, when the optical cable 1 is bent, when an elongation strain occurs at a certain location of the optical fiber 3A, a compressive strain occurs at a location in the immediate vicinity thereof, so that the optical fiber 3A is displaced in the longitudinal direction within the optical cable 1. By doing so, the elongation strain and the compression strain are offset, and the strain hardly remains in the optical fiber 3A. For this reason, elongation strain does not remain in the optical fiber 3A, and it can be suppressed that the breaking life of the optical fiber 3A is shortened.

  Since the opening part 13 of the eyeplate 12 of 1st Embodiment is square shape, it has a linear part. Thus, when the opening 13 has a straight portion, the opening 13 restrains the plurality of optical fibers 3A (the plurality of optical fibers 3A arranged in the width direction) of the optical fiber tape 3 when the eye plate 12 rotates. This is advantageous because it is easy to do. In other words, in order to constrain the plurality of optical fibers 3 </ b> A of the optical fiber tape 3 to the opening 13 of the eyeplate 12, the width direction of the optical fiber tape 3 is set to the direction of the straight portion of the opening 13 of the eyeplate 12. It is desirable to bring the surface of the optical fiber tape 3 into contact with the straight portion of the opening 13 of the eye plate 12 (while keeping the surface of the optical fiber tape 3 along the straight portion).

  In addition, since the opening 13 of the eyeplate 12 of the first embodiment has a square shape (rectangular shape), a plurality of laminated optical fiber tapes 3 are stacked on two sides (two opposite sides) of the opening 13. The optical fiber unit 2 can be inserted through the opening 13 while being sandwiched from the direction. Thereby, when the eyeplate 12 rotates, it is further advantageous because the openings 13 can easily restrain the plurality of optical fibers 3A (the plurality of optical fibers 3A arranged in the width direction) of the optical fiber tape 3.

  In order to allow the opening 13 to restrain the optical fiber unit 2 when the eye plate 12 rotates, the ratio of the area of the optical fiber unit 2 to the opening area of the opening 13 is 60% or more. Is desirable, and it is more desirable that it is 65% or more. If this ratio is 60% or more, the strain of the optical fiber 3A can be reduced by canceling out the elongation strain and the compression strain of the optical fiber 3A. Furthermore, if this ratio is 65% or more, it is possible to prevent elongation strain from occurring in the optical fiber 3A.

<Modification of First Embodiment>
FIG. 11 is an explanatory diagram of the eyeplate 12 of a modification of the first embodiment. 12A to 12D are explanatory diagrams illustrating a state when the eye plate 12 according to the modified example of the first embodiment is rotated. The eye plate 12 of this modification includes a rectangular (substantially rectangular) opening 13 as the non-circular opening 13.

  Also in this modified example, when the eye plate 12 is rotated, the optical fiber unit 2 is constrained in the opening 13 and twisted without spinning. As a result, when the eye plate 12 rotates, the distance between the center of rotation of the eye plate 12 and the optical fiber 3A does not change. For this reason, as in the case of the first embodiment (when the opening 13 has a square shape), when the optical cable 1 is bent, it becomes easy to cancel the elongation strain and the compression strain of the optical fiber 3A.

  Moreover, since the opening part 13 of the eyeplate 12 of a modification is rectangular shape, it has a linear part. For this reason, also in the modified example, when the eye plate 12 rotates, the openings 13 tend to restrain the plurality of optical fibers 3A (the plurality of optical fibers 3A arranged in the width direction) of the optical fiber tape 3. In other words, also in the modified example, in order to constrain the plurality of optical fibers 3A of the optical fiber tape 3 to the opening 13 of the eye plate 12, the width direction of the optical fiber tape 3 is changed to the straight line of the opening 13 of the eye plate 12. It is desirable to bring the surface of the optical fiber tape 3 into contact with the straight portion of the opening 13 of the eyeplate 12 while keeping the direction of the portion.

=== Second Embodiment ===
FIG. 13 is an explanatory diagram of the eyeplate 12 of the second embodiment. The eye plate 12 of the second embodiment includes an elliptical opening 13 as the non-circular opening 13. Unlike the opening 13 (square or rectangular opening 13) of the first embodiment described above, the opening 13 of the eyeplate 12 of the second embodiment has no straight portion, but the opening 13 is not. Since it is circular, the opening 13 can restrain the optical fiber unit 2 when the eye plate 12 rotates.

  FIG. 14 is an explanatory diagram of the eyeplate 12 of a modification of the second embodiment. The eye plate 12 of this modification includes a D-shaped opening 13 as the non-circular opening 13. Also in this modified example, since the opening 13 is non-circular, when the eye plate 12 is rotated, the optical fiber unit 2 is restrained in the opening 13 and twisted without spinning. Also in this modification, in order to constrain the plurality of optical fibers 3 </ b> A of the optical fiber tape 3 to the opening 13 of the eyeplate 12, the width direction of the optical fiber tape 3 is set to the straight line of the opening 13 of the eyeplate 12. It is desirable to bring the surface of the optical fiber tape 3 into contact with the straight portion of the opening 13 of the eyeplate 12 while keeping the direction of the portion.

=== Third Embodiment ===
In the first and second embodiments described above, the eye plate 12 (rotary plate) immediately before the assembly die 14 has a plurality of non-circular openings 13. However, the non-circular opening 13 may be arranged on another rotating plate.

  FIG. 15 is an explanatory diagram of the collective machine 11 according to the third embodiment. The collective machine 11 of the third embodiment includes a first eye plate 12A and a plurality of second eye plates 12B. Although only one second eye plate 12B is illustrated in the drawing, the collective machine 11 actually has four second eye plates 12B.

  The first eye plate 12A is a rotating plate immediately before the collective die 14 (see FIG. 4), and has a plurality of openings 13A (here, four openings 13A). The first eye plate 12A is disposed on the downstream side of the second eye plate 12B. The opening 13A of the first eye plate 12A does not have to be non-circular, and here is circular.

  The second eye plate 12B is a rotating plate disposed on the upstream side of the first eye plate 12A. A non-circular opening 13B is formed in the second eye plate 12B. The optical fiber unit 2 is inserted through the non-circular opening 13B of the second eye plate 12B and is inserted through the circular opening 13A of the first eye plate 12A.

When manufacturing the optical cable 1, the collecting machine 11 rotates the first eye plate 12 </ b> A and twists the plurality of optical fiber units 2. At this time, the collecting machine 11 rotates the second eye plate 12B in accordance with the rotation of the first eye plate 12A. For example, when the first eye plate 12A rotates 45 degrees, the collective machine 11 also rotates the second eye plate 12B by 45 degrees. Since the opening 13B of the second eye plate 12B is non-circular, when the second eye plate 12B is rotated, the optical fiber unit 2 is restrained by the opening 13B of the second eye plate 12B and does not rotate freely. To be twisted. Then, the optical fiber unit 2 twisted by the second eye plate 12B is supplied to the opening 13A of the first eye plate 12A. For this reason, although the opening 13A of the first eye plate 12A is circular, there is almost no idle rotation between the opening 13A of the first eye plate 12A and the optical fiber unit 2.
Therefore, also in the third embodiment, when the first eye plate 12A rotates, the distance between the rotation center of the first eye plate 12A and the optical fiber 3A does not need to change. Also in the third embodiment, when the optical cable 1 is curved, the elongation strain and the compression strain of the optical fiber 3A can be offset within a range of 1 pitch.

=== Example ===
A single optical fiber unit was composed of four 12-fiber intermittently fixed optical fiber tapes, and the four optical fiber units were twisted into the SZ type to produce a 192-fiber optical cable.
In the first example, four optical fiber units were twisted together using a grid having four square openings shown in FIG. In the second example, four optical fiber units were twisted together using a grid having four rectangular openings shown in FIG. In the third example, as shown in FIG. 15, four optical fiber units were twisted together using a first eye plate and a plurality of second eye plates. Further, as a comparative example, four optical fiber units were twisted together using a grid having four circular openings shown in FIG. 5A.
As an evaluation method of the optical cables of the first to third examples and the comparative example, each optical cable was wound around a drum having a body diameter of 800 mm by 500 m, and distortion measurement by the BOTDR method was performed. In addition, the optical cable was evaluated based on the maximum value of the distortion in all the optical fibers constituting the optical cable. The evaluation results are shown below.

  As shown in the evaluation results of Table 1, it was confirmed that the optical fiber of the optical cable of the comparative example had a large elongation distortion, whereas the optical fiber of the optical cable of the first to third examples suppressed the distortion. It was done. Thereby, the effect that the opening part of the eyeplate is non-circular was confirmed.

Next, the influence of the ratio (hereinafter referred to as area ratio) of the cross-sectional area Y (mm ² ) of the optical fiber unit to the area S (mm ² ) of the opening of the eyeplate was confirmed. Here, the cross-sectional area of the optical fiber unit is an area of a circle obtained by approximating the cross-section of the optical fiber bundle in a circle. The area Y (mm ² ) of this circle is expressed by the following approximate expression, where X is the number of optical fiber cores.
Y = 0.106X + 0.9777

  Prepare eye plates with different areas S of the openings in the area ratio of 50% to 100% (that is, Y / S is in the range of 0.5 to 1.0). An optical cable was manufactured in the same manner as in the first example. Then, each optical cable was wound around a drum having a trunk diameter of 800 mm by 500 m, and distortion measurement by the BOTDR method was performed. In addition, the optical cable was evaluated based on the maximum value of the distortion in all the optical fibers constituting the optical cable. The evaluation results are shown below.

As shown in the evaluation results of Table 2, it is confirmed that the strain is suppressed when the area ratio is in the range of 65% to 95% (that is, Y / S is in the range of 0.65 to 0.95). It was done. When the area ratio was 100%, the optical fiber was disconnected, and the optical cable could not be substantially evaluated. Further, when the area ratio was 60% or less, a large elongation strain occurred in the optical fiber. This is thought to be because the opening was too large for the optical fiber unit, resulting in idle rotation between the opening and the optical fiber unit.
When the optical cable 1 is manufactured, the length of the optical fiber 3A relative to the length of the optical cable 1 is increased by 0.05% to 0.10% so that the fracture life of the optical fiber 3A is not shortened. Generally, compressive strain is applied to the optical fiber 3A in advance. However, this compressive strain is alleviated by bending the optical fiber 3 </ b> A so as to meander in the optical cable 1. Because of such factors at the time of manufacturing the optical cable 1, it is considered that a slight compressive strain was measured in the evaluation results of Examples 1 to 3 in Table 1 and the area ratio of 65% to 95% in Table 2.

=== Others ===
The above-described embodiments are for facilitating the understanding of the present invention, and are not intended to limit the present invention. The present invention can be modified and improved without departing from the gist thereof, and it goes without saying that the present invention includes equivalents thereof.

1 optical cable, 2 optical fiber unit,
3 optical fiber tape, 3A optical fiber, 3B connecting part,
4 Bundle material, 6 Presser winding tape, 7 Outer jacket,
8 strength members, 9 tear strings,
10 manufacturing equipment, 11 collecting machines,
12 eye plate (rotary plate), 12A first eye plate, 12B second eye plate,
13 (13A, 13B) opening,
14 Assembly dies, 16 Extruder

Claims (7)

A method of manufacturing a slotless optical cable comprising a plurality of optical fiber units in which a plurality of optical fibers are bundled,
Inserting the optical fiber unit through a non-circular opening of the rotating plate of the collecting machine; and
While twisting the plurality of optical fiber units while rotating the rotating plate ,
The rotating plate has a plurality of non-circular openings that extend long in the same direction,
A method of manufacturing an optical cable, wherein the plurality of optical fiber units are twisted together while rotating the rotating plate in a state where the optical fiber units are inserted through the openings . It is a manufacturing method of the optical cable according to claim 1,
The said opening part has a linear part, The manufacturing method of the optical cable characterized by the above-mentioned. It is a manufacturing method of the optical cable according to claim 2,
The optical fiber unit has a plurality of optical fiber tapes,
A method of manufacturing an optical cable, wherein the optical fiber unit is inserted into the opening while keeping the surface of any one of the optical fiber tapes along the straight portion. It is a manufacturing method of the optical cable according to claim 2 or 3,
The method of manufacturing an optical cable, wherein the opening is substantially rectangular. It is a manufacturing method of the optical cable according to claim 1,
The method of manufacturing an optical cable, wherein the opening has an elliptical shape. It is a manufacturing method of the optical cable in any one of Claims 1-5 ,
The area of the opening is S (mm ² ),
The number of the optical fibers constituting the optical fiber unit is X,
When the cross-sectional area Y (mm ² ) of the optical fiber unit is represented by an approximate expression as Y = 0.106X + 0.9777,
A ratio Y / S of the cross-sectional area Y of the optical fiber unit to the area S of the opening is 0.65 to 0.95.   A slotless type optical cable manufacturing apparatus including a plurality of optical fiber units in which a plurality of optical fibers are bundled,
  A rotating machine having a non-circular opening through which the optical fiber unit is inserted, and a gathering machine that twists the optical fiber units together,
  The rotating plate has a plurality of non-circular openings that extend long in the same direction,
  A plurality of optical fiber units are twisted together while rotating the rotating plate in a state where the optical fiber units are inserted through the openings.
An optical cable manufacturing apparatus.

Images