JP2016080850A - Optical fiber cable and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical fiber cable and the like that reliably prevent optical fiber core wires from protruding, and is excellent in manufacturability and taking-out work efficiency of coated optical fibers.SOLUTION: A circumferential length of a press-winding tape 7 cylindrically formed on an outer circumference of an optical fiber unit 5 is defined as B, and length of an overlapping part 8 in a circumferential direction is defined as C. In this case, the overlapping part 8 is formed so that the overlapping rate of the overlapping length C to the whole circumferential length B is 50% or more. That is, it is set so that C/B≥0.5 is satisfied. In order to set like this, the width of the press-winding tape 7 is to be set with respect to the circumferential length of the optical fiber unit 5. That is, the width of the press-winding tape 7 is set so that the overlapping part length C/(a press-winding tape width W-the overlapping part length C)≥0.5 is satisfied.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an optical fiber cable composed of a plurality of optical fiber core wires and the like.

  Conventionally, a slot-type optical fiber cable with a built-in optical fiber inside and a coating layer formed on the outermost periphery is prevented from being subjected to concentrated force on the internal optical fiber by external force or the like. Fiber optic cable is used. As such a slot-type optical fiber cable, for example, an optical fiber is accommodated in a groove of a slot rod, a press-wrapping tape is vertically wound around the outer periphery, and an outer jacket is extruded and coated (for example, a patent) References 1, 2). In this case, the wrap portion of the press-wound tape is joined by fusion or adhesion, or further, a coarse winding string is wound around the outer periphery to prevent the press-wound tape from opening and the optical fiber core wire jumps out. Is prevented.

  On the other hand, slotless type optical fiber cables that do not use slot rods are also used. As such an optical fiber cable, for example, yarn (polyester fiber, aramid fiber, PP fiber, etc.) is gathered as a buffer material on the outer periphery of the optical fiber core, and a sheath is coated on the outer periphery (see FIG. Patent Document 3).

  In addition, there is an optical fiber cable in which a press-wrapping tape is vertically wound around the outer periphery of the optical fiber core and the outer sheath is coated on the outer periphery (Patent Document 4).

JP 2004-012914 A JP 2007-304347 A JP 2006-337581 A JP 2001-343571 A

  However, slot type optical fiber cables such as Patent Documents 1 and 2 are expensive in slot rods, and the entire outer diameter of the optical fiber cable is increased. For this reason, in order to achieve higher density and smaller diameter, a slotless type optical fiber cable may be used.

  However, the slotless type optical fiber cable as in Patent Document 3 is provided with a buffer layer on the outer periphery of the optical fiber core, so that the workability of taking out the internal optical fiber core is poor. For example, when taking out an optical fiber core wire, there is a possibility of cutting the optical fiber core wire together with the cutting of the yarn constituting the buffer layer. Further, since the yarn after removal becomes fibrous waste, there is a problem in handling.

  On the other hand, as in Patent Document 4, in a structure in which a press-wrapping tape is wound around the outer periphery of the optical fiber core wire, the yarn is not used. It is unnecessary.

  However, in order to prevent the optical fiber core wire from jumping out from the press-winding tape, for example, it is necessary to join a wrap portion of the press-winding tape or to use a rough winding string or the like on the outer periphery of the press-winding tape. However, with such a configuration, the number of manufacturing processes increases and the workability of taking out the optical fiber core wire deteriorates. Therefore, an optical fiber cable that reliably prevents the optical fiber core from jumping out and is excellent in manufacturability and workability for taking out the optical fiber core is desired.

  The present invention has been made in view of such problems, and provides an optical fiber cable or the like that reliably prevents the optical fiber core wire from jumping out and is excellent in manufacturability and workability for taking out the optical fiber core wire. For the purpose.

  In order to achieve the above-described object, the first invention is provided to cover an optical fiber unit composed of a plurality of optical fiber core wires, a press winding tape provided on an outer peripheral portion of the optical fiber unit, and the press winding tape. The press-wrapping tape, the longitudinal direction of the press-wrapping tape substantially coincides with the axial direction of the optical fiber cable, and the width direction of the press-wrapping tape is the circumferential direction of the optical fiber cable. As described above, the wrap ratio that is the wrap length in the circumferential direction of the press-wound tape with respect to the peripheral length of the press-wound tape that is vertically attached to the outer periphery of the optical fiber unit and formed into a cylindrical shape is 50% or more. Is an optical fiber cable.

  The wrap portion of the press-wound tape is desirably a non-joined portion that is not fused or bonded.

  The reduction rate in the width direction when a tension of 50 N is applied to the press-wound tape is desirably 10% or less.

  The press-wrapping tape is formed in a cylindrical shape in advance, and an inner diameter of the formed cylindrical body is smaller than an outer diameter of the optical fiber unit, and the optical fiber unit is inserted into the cylindrical body. In this case, the cylindrical body may be expanded by the optical fiber unit, and the cylindrical body and the optical fiber unit may be brought into close contact with each other.

  According to 1st invention, the opening of a press-wound tape can be prevented by making the wrap rate of a press-wound tape into 50% or more. For this reason, it is not necessary to provide a rough winding string further on the outer periphery. Therefore, it is not necessary to cut and remove the rough winding string when taking out the internal optical fiber core, so that the workability of taking out the optical fiber core is good.

  In particular, the workability of taking out the optical fiber core wire can be further enhanced by making the wrap portion of the press-wound tape a non-bonded portion that is not fused or bonded.

  Moreover, the change of the width of the press-wound tape at the time of the longitudinal wrapping of the press-wound tape can be suppressed by setting the reduction rate in the width direction when a tension of 50 N is applied to the press-wound tape to 10% or less. For this reason, the wrap rate of 50% or more can be secured stably.

  Since the press-winding tape is formed in a cylindrical shape and is spread by the optical fiber unit, the press-winding tape and the optical fiber unit are brought into close contact with each other by a force for the press-winding tape to return to the original diameter. For this reason, an optical fiber cable having a small outer diameter can be obtained.

  According to a second aspect of the present invention, there is provided a plurality of pressing tapes such that the longitudinal direction of the pressing tape substantially coincides with the axial direction of the optical fiber cable and the width direction of the pressing tape is the circumferential direction of the optical fiber cable. A step of longitudinally winding the outer periphery of an optical fiber unit made of an optical fiber core wire, and a step of directly covering and covering the outer periphery of the press-wound tape without wrapping a coarse winding string. The wrap ratio, which is the wrap length in the circumferential direction of the press-winding tape with respect to the peripheral length of the press-winding tape formed in a shape, is 50% or more.

  The step of vertically attaching the press-wound tape includes a step of rounding and heating the press-wound tape so that a width direction thereof is a circumferential direction, forming a tubular body, opening a wrap portion of the tubular body, And inserting the optical fiber unit composed of a plurality of optical fiber cores into the cylindrical body, and returning the cylindrical body to its original form, and the inner diameter of the cylindrical body formed is that of the optical fiber unit. When the optical fiber unit is inserted into the cylindrical body that is smaller than the outer diameter, the cylindrical body may be expanded by the optical fiber unit.

  According to the second invention, since it is not necessary to provide a rough winding string, it is possible to obtain a method for manufacturing an optical fiber cable which has good manufacturability and good workability for taking out the optical fiber core wire.

  Moreover, the cylindrical body which hold | maintained the cylindrical shape can be formed by first forming a press-wound tape in a cylindrical shape and heating it. At this time, since the holding tape is not wound around the outer periphery of the optical fiber unit, there is no need to provide a clearance between the optical fiber unit and the holding tape. Therefore, the outer diameter of the optical fiber cable can be reduced by an amount corresponding to the clearance. Further, since the press-winding tape itself maintains a cylindrical shape, the optical fiber core wire can be prevented from jumping out without winding a rough winding string or the like around the outer periphery.

  According to the present invention, an optical fiber cable or the like excellent in manufacturability and workability of taking out an optical fiber core can be provided while reliably preventing the optical fiber core from jumping out.

1 is a cross-sectional view showing an optical fiber cable 1; The figure which shows the wrapping state of the press-wound tape 7. FIG. The figure which shows the manufacturing process of the optical fiber cable. FIG. 4 is a cross-sectional view taken along line YY in FIG. 3. The figure which shows the manufacturing process of the optical fiber cable. FIG. 6 is a cross-sectional view of the press-winding tape 7 showing a process of covering the optical fiber unit 5 with the press-winding tape 7, where (a) is a cross-sectional view of an M portion in FIG. 5 and (b) is a cross-sectional view of an N portion in FIG. FIG. 6 is a cross-sectional view of the press-winding tape 7 showing a process of covering the optical fiber unit 5 with the press-winding tape 7, where (a) is a cross-sectional view of an O portion in FIG. 5 and (b) is a cross-sectional view of a P portion in FIG. The figure which shows the cylindrical body 20a. The figure which shows the evaluation method of the pressing tape 7. (A) is a figure which shows the state which bent the optical fiber cable 1, (b) is a figure which shows the state of the wrap part 8 at the time of normal, (c) is a wrap part at the time of bending the optical fiber cable 1 FIG. Sectional drawing which shows the optical fiber cable 1a. The figure which shows the state which removed the jacket of the optical fiber cable.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing an optical fiber cable 1. The optical fiber cable 1 is a slotless cable that does not use a slot, and includes a plurality of optical fiber cores 3, a press winding tape 7, a tension member 9, a tear string 11, a jacket 13, and the like. In the following description, an assembly of a plurality of optical fiber cores 3 is simply referred to as an optical fiber unit 5. The optical fiber unit 5 is, for example, an assembly of 200 optical fibers 3 having a single core of Φ0.25 mm.

  On the outer periphery of the optical fiber unit 5, a press-wound tape 7 is provided. The presser winding tape 7 is disposed so as to cover the outer periphery of the optical fiber unit 5 by vertical additional winding. In other words, the longitudinal direction of the press-winding tape 7 is substantially aligned with the axial direction of the optical fiber cable 1, and is vertically attached to the outer periphery of the optical fiber unit 5 so that the width direction of the press-winding tape 7 is the circumferential direction of the optical fiber cable 1. It is wound.

  The press-wound tape 7 thus formed in a cylindrical shape has a wrap portion 8 formed in the circumferential direction. That is, both ends in the width direction of the press-wound tape 7 overlap. The wrap portion 8 is a non-joined portion that is not joined to each other by fusion or adhesion. In addition, about the form of the lap | wrap part 8, a detail is mentioned later.

  There is no restriction | limiting in particular in the material of the press-wound tape 7, It can select suitably. For example, polyolefins (eg, low density polyethylene, high density polyethylene, polypropylene, etc.), polyamides (PA) (eg, nylon-6, nylon-12, etc.), polyacetals (POM), polyesters (eg, PET, PEN, PTT, PBT, PPT, PHT, PBN, PES, PBS, etc.), syndiotactic polystyrene (SPS), polyphenylene sulfides (PPS), polyether ether ketones (PEEK), liquid crystal polymers (LCP), A fluororesin, isotactic polypropylene (isoPP), or the like can be used. Among these, polyolefins, polyesters, and syndiotactic polystyrene (SPS) are preferable from the viewpoint of durability, mechanical strength, and cost, and polyesters are particularly preferable.

  As the press-wound tape 7, for example, a uniaxially or biaxially stretched film (tape) can be used. Preferably, a biaxially stretched film is preferable in consideration of tension during cable forming. A nonwoven fabric tape can be used as the other tape. Moreover, what bonded the nonwoven fabric tape and the film can also be used. In addition, for the purpose of improving the peelability from the outer cover 13 to be described later, for example, a surface coated with a lubricant such as oils, wax, silicone or the like, for example, a surface subjected to uneven processing It can also be used.

  An outer cover 13 is provided on the outer periphery of the press-wound tape 7. The jacket 13 is a layer for covering and protecting the optical fiber cable 1. A tension member 9 and a tear string 11 are embedded in the outer cover 13 as necessary.

  Next, the wrap part 8 of the press-winding tape 7 will be described. FIG. 2 is a view showing a wrap state of the press-wound tape 7. The total circumferential length of the press-wound tape 7 formed in a cylindrical shape on the outer periphery of the optical fiber unit 5 is B, and the length of the circumferential wrap portion 8 is C. In this case, the wrap portion 8 is formed so that the wrap length C (wrap ratio) with respect to the entire circumference B is 50% or more. That is, C / B ≧ 0.5.

  In order to do this, the width of the holding tape 7 may be set with respect to the circumference of the optical fiber unit 5. That is, the width of the press-wound tape 7 may be set so that the wrap length C / (press-wrap tape width W-wrap-portion length C) ≧ 0.5. At this time, it is desirable to set the width of the press-winding tape 7 in consideration of the elongation (reduction in width) of the press-winding tape 7.

  When the wrap ratio increases, the internal optical fiber core can be more reliably prevented from jumping out, but when the optical fiber core is taken out, it is difficult to open the holding tape 7. In particular, when the wrap rate exceeds 100%, a portion that wraps three times is formed, so that it is more difficult to open the press-wrapping tape 7. Therefore, it is desirable that the wrap rate is 100% or less.

  Next, a method for manufacturing the optical fiber cable 1 will be described. FIG. 3 is a schematic diagram of an apparatus for manufacturing the optical fiber cable 1. The tension member 9 and the tear string 11 are not shown. The presser winding tape 7 and the optical fiber unit 5 are sent to the forming device 15. The forming device 15 is a member whose tip is rounded and reduced in diameter. The presser tape 7 is rolled along the forming device 15 as it goes to the tip. At this time, the press-wound tape 7 is formed in a cylindrical shape so as to cover the outer periphery of the internal optical fiber unit 5.

  The press-wound tape 7 formed in a cylindrical shape so as to cover the outer periphery of the optical fiber unit 5 is introduced into the guide 17. The guide 17 is a cylindrical member, and is a part that holds the cylindrical shape of the press-winding tape 7 and introduces it into the jacket extruder 19. The forming device 15, the guide 17, and the nipple (not shown) arranged in the jacket extruder 19 are arranged on a substantially straight line. The tip of the guide 17 is positioned in the vicinity of the end of a nipple (not shown) disposed in the jacket extruder 19 until the guide 17 is introduced into the nipple from the forming device 15 by the guide 17. Is retained.

  A tension member 9 and a tear string 11 (not shown) are introduced into the jacket extruder 19, and the jacket 13 is pushed out to the outer periphery of the press-winding tape 7. The jacket 13 is, for example, low density polyethylene, and the thickness of the jacket 13 is, for example, about 2.0 mm. The optical fiber cable 1 formed as described above passes through a cooling water tank (not shown) and is wound up by a winder.

  Moreover, the optical fiber cable 1 can also be manufactured as follows. 4 is a cross-sectional view taken along line YY of FIG. Since the optical fiber unit 5 and the presser winding tape 7 pass through the inside of the tip of the forming device 15, a clearance is formed between the optical fiber unit 5 and the presser winding tape 7. Further, a clearance is formed between the press-winding tapes 7 at least by the thickness of the forming device 15 at a site where the press-winding tapes 7 are rolled and wrapped.

  Therefore, the outer diameter of the press-wound tape 7 is larger than the outer diameter of the optical fiber unit 5 by the clearance in a state where it passes through the forming device 15. For this reason, when a jacket having a predetermined thickness is pushed out to the outer periphery of the press-winding tape 7, an optical fiber cable having a larger diameter than necessary is formed.

  On the other hand, in the optical fiber manufacturing apparatus shown in FIG. 5, first, the press-wound tape 7 is sent to the forming apparatus 15 (arrow A in the figure).

  FIG. 6A is a cross-sectional view of the press-wound tape 7 in the portion M of FIG. The press-winding tape 7 sent to the forming device 15 has a flat linear shape. The forming device 15 is a member whose tip is rounded and reduced in diameter. The presser winding tape 7 is rounded along the forming device 15 toward the tip, and becomes a cylindrical shape.

  The press-wound tape 7 exiting the forming device 15 is introduced into the forming device 27 while maintaining the cylindrical shape. The molding apparatus 27 has a cylindrical guide part and a heating part. The press-winding tape 7 introduced into the molding device 27 is heated at a temperature and time at which the press-winding tape 7 is softened and stretched by the heating unit while being inserted into the guide portion and held in a cylindrical shape. .

  FIG. 6B is a cross-sectional view of the press-wound tape 7 at the N portion in FIG. By the forming device 27, the press-wound tape 7 is formed into a cylindrical body 20 with a cylindrical mold. That is, the cylindrical body 20 maintains the cylindrical shape molded by the molding device 27.

  The press-wound tape 7 (cylindrical body 20) that has exited the molding device 27 is sent to the optical fiber unit insertion device 28. The optical fiber unit 5 is sent to the optical fiber unit insertion device 28 (arrow Q in the figure). In the optical fiber unit insertion device 28, the wrap portion of the cylindrical body 20 is expanded, and the optical fiber unit 5 is inserted therein.

  FIG. 7A is a cross-sectional view of the press-wound tape 7 at the portion O in FIG. The optical fiber unit insertion device 28 widens the wrap portion of the cylindrical body 20 (arrow I in the figure), and the optical fiber unit 5 is inserted from the opening (arrow J in the figure). After the optical fiber unit 5 is inserted, the press-wound tape 7 returns to the original state (cylindrical body 20) and is sent to the jacket extruder 19.

  In addition, the method of opening the cylindrical body 20 is not specifically limited. For example, you may use the wiring jig for tubes with a slit conventionally used. The optical fiber unit 5 may be inserted by opening the wrap portion of the tubular body 20 to the extent that the optical fiber unit 5 can be inserted with a wiring jig.

  FIG. 7B is a cross-sectional view of the press-wound tape 7 in the P portion of FIG. When being sent to the jacket extruder 19, the press-wound tape 7 becomes cylindrical again due to the restoring force applied to the cylindrical body 20 (arrow K in the figure).

  Here, the inner diameter (H in FIG. 6B) of the initially formed cylindrical body is smaller than the outer diameter of the optical fiber unit 5 (L in FIG. 7B). Therefore, the press-wound tape 7 does not completely return to the original shape, but has a cylindrical shape that is spread by the optical fiber unit 5. Therefore, the inner surface of the press-wound tape 7 is pressed against and closely adhered to the outer peripheral surface of the optical fiber unit 5. Similarly, the press-wound tapes 7 are in close contact with each other at the wrap portion of the press-wound tape 7. For this reason, it is possible to suppress an unnecessary clearance from being formed inside the press-wound tape 7.

  The cylindrical shape of the press-wound tape 7 is not limited to a cylindrical shape. For example, it is good also as a polygonal cylinder shape like the cylindrical body 20a shown in FIG. Even in this case, it is desirable that the inner diameter of the cylindrical body 20 a be smaller than the outer diameter of the optical fiber unit 5 so as to be in close contact with the outer peripheral portion of the optical fiber unit 5. By doing in this way, the press-wrapping tape 7 can be more closely attached to the outer peripheral surface of the optical fiber unit 5. Thus, the cross-sectional shape of the cylindrical body can be set as appropriate.

  Here, it is desirable that the press-winding tape 7 to be used has a width reduction rate of 10% or less at the time of 50 N tension in the longitudinal direction. FIG. 9 is a diagram showing a method for evaluating the width reduction rate of the press-wound tape 7. The press-wound tape to be evaluated has a width of 30 mm and a length of 250 mm. First, both ends of the presser winding tape 7 are grasped by the chuck 23. At this time, the press-wound tape 7 is set on the chuck 23 so that the distance between the chucks 23 becomes 200 mm. Next, a force of 50 N is applied in the longitudinal direction of the press-wound tape 7 (in the direction of arrow R in the figure).

  In this state, hold for 30 seconds, and measure the width (narrowest part) of the press-wound tape 7 after 30 seconds in a state where a force of 50 N is applied. The width reduction rate of the presser tape 7 is calculated by {initial width− (width after 30 seconds)} / initial width. In the present invention, it is desirable that the width reduction rate of the press-wound tape 7 is 10% or less.

  As described above, when the optical fiber cable 1 is manufactured, the outer jacket 13 is wound around the outer periphery of the press-winding tape 7 while being wound. At this time, tension is applied to the presser tape 7 in the longitudinal direction. Since the tension is usually about 40 to 50 N, the press-winding tape 7 is stretched in the longitudinal direction by this tension. That is, the width of the press-winding tape 7 is reduced.

  Here, when the width reduction rate of the press-winding tape 7 exceeds 10%, the change in the width of the press-winding tape 7 becomes large when the optical fiber cable 1 is manufactured. For this reason, it is difficult to control the width of the press-winding tape 7. As described above, the wrap rate of the press-winding tape 7 is set by the width of the press-winding tape 7. For this reason, when the change in the width of the press-winding tape 7 becomes large, it becomes difficult to stably secure a wrap rate of 50% or more. For this reason, in order to stably secure the wrap rate of 50%, the width reduction rate of the press-wound tape 7 is desirably 10% or less.

  Next, the function of the optical fiber cable 1 will be described. Fig.10 (a) is a figure which shows the state which bent the optical fiber cable 1 which removed the jacket. When the optical fiber cable 1 is bent (in the direction of arrow D in the figure), the inner peripheral side E of the optical fiber cable 1 is compressed and the outer peripheral side F is tensile bent.

  As shown in FIG. 10B, in the normal state (the state where there is no bending), the press-wound tape 7 maintains the shape when manufactured. However, when the optical fiber cable 1 is bent, the press-wrapping tape 7 is deformed as shown in FIG. At this time, in particular, on the inner circumferential side E of the bending, the presser winding tape 7 is easily deformed so as to spread outward (in the direction of arrow G in the figure). For this reason, if the front-end | tip of the lap | wrap part 8 is located in the inner peripheral side E, it will be easy to deform | transform in the direction in which the press winding tape 7 opens.

  On the other hand, on the outer peripheral side F of the bending of the optical fiber cable 1, it is easy to be deformed in the direction in which the wrap portion 8 is closed (the direction of arrow H in the figure). Here, if the wrap ratio of the wrap portion 8 is small, the wrap portion 8 may be opened when the tip of the wrap portion 8 is on the bending inner peripheral side, and the internal optical fiber core wire 3 may jump out. However, in the present invention, even when the tip of the wrap portion 8 that is most likely to open the press-wrapping tape 7 is positioned on the bending inner peripheral side E, the wrap portion 8 is formed with the other end exceeding the outer peripheral side F. For this reason, on the outer peripheral side F, the presser winding tape 7 is deformed in the closing direction. Therefore, the press-wound tape 7 does not open completely, and the internal optical fiber core wire 3 can be prevented from popping out.

  As described above, according to the present embodiment, the press-wound tape 7 is opened, and the optical fiber core wire 3 can be prevented from jumping out. At this time, it is not necessary to wind a coarsely wound string around the outer periphery of the press-winding tape 7. For this reason, it is excellent in manufacturability and is excellent in workability for taking out the optical fiber core wire 3.

  Further, since the press-wound tape 7 does not open, it is not necessary to join the wrap portion 8 of the press-winding tape by fusion or the like. For this reason, it is excellent in manufacturability and is excellent in workability for taking out the optical fiber core wire 3.

  Moreover, the wrap rate of 50% or more can be stably secured by setting the width reduction rate of the press-wound tape 7 to 10% or less.

  Next, a second embodiment will be described. FIG. 11 is a diagram showing the optical fiber cable 1a. In the following description, components having the same functions as those of the optical fiber cable 1 are denoted by the same reference numerals as those in FIG.

  The optical fiber cable 1a has substantially the same configuration as the optical fiber cable 1, but differs in that a support line 21 is provided. The optical fiber cable 1a is a self-supporting optical fiber cable, and the support line 21 and the cable portion are connected via a neck portion. The support wire 21 is, for example, a steel wire or the like, and is configured integrally with the cable portion (same configuration as the optical fiber cable 1) by the jacket 13.

  Also in the optical fiber cable 1a, the press-wrapping tape 7 is vertically wound around the outer periphery of the optical fiber unit 5 so that the wrap ratio of the wrap portion 8 is 50% or more. Further, if necessary, the press-wound tape 7 can be formed into a cylindrical shape and brought into close contact with the optical fiber unit 5.

  According to the second embodiment, an effect similar to that of the first embodiment can be obtained. Thus, in the present invention, the cross-sectional structure is not particularly limited as long as the wrap ratio of the press-winding tape 7 can be 50% or more.

  Actually, an optical fiber cable 1 as shown in FIG. 1 was prepared, and the presence or absence of the optical fiber core wire 3 was confirmed. On the outer periphery of the optical fiber unit 5 in which 200 optical fiber cores 3 having a diameter of 0.25 mm were assembled, a press-wrapping tape 7 was vertically wound around the wrap ratio. An outer cover having a thickness of 2.0 mm was extruded and coated on the outer periphery of the press-wound tape 7 together with the tear string 11 and the tension member 9.

  At both ends of the obtained optical fiber cable 1, the optical fiber core 3 and the jacket are fixed so that the optical fiber core 3 does not move. The both ends of the optical fiber cable 1 were attached to the support | pillar installed in the space | interval of 3 m, and the optical fiber cable 1 was loosened moderately. As shown in FIG. 12, the jacket 13 was removed from the installed optical fiber cable 1 for 1 m (S in the figure) at the approximate center of the cable. The outer jacket 13 was removed by splitting the outer jacket 13 into two in the longitudinal direction by the tear string 11 and then removing the outer jacket 13 and the tension member 9.

  In this state, it was confirmed that the optical fiber core wire 3 was not popped out by the optical fiber unit 5 being loosened by its own weight. The results are shown in Table 1.

  As shown in Table 1, when the wrap ratio was less than 50%, the optical fiber core wire 3 was confirmed to be popped out. However, when the wrap ratio was 50% or higher, the optical fiber core wire 3 was not popped out.

  As mentioned above, although embodiment of this invention was described referring an accompanying drawing, the technical scope of this invention is not influenced by embodiment mentioned above. It is obvious for those skilled in the art that various modifications or modifications can be conceived within the scope of the technical idea described in the claims, and these are naturally within the technical scope of the present invention. It is understood that it belongs.

DESCRIPTION OF SYMBOLS 1, 1a ... Optical fiber cable 3 ... Optical fiber core wire 5 ... Optical fiber unit 7 ... Pressing tape 8 ... Wrap part 9 ... Tension member 11 ... Tear string 13 ......... Coat 15 ......... Forming device 17 ......... Guide 19 ......... Coat extruding machine 20, 20a ......... Cylindrical body 21 ......... Support wire 23 ......... Chuck 27 ......... Molding device 28 ... Optical fiber unit insertion device

Claims (6)

An optical fiber unit comprising a plurality of optical fiber cores;
A holding tape provided on the outer periphery of the optical fiber unit;
A jacket provided so as to cover the pressing tape,
Comprising
The presser winding tape is arranged on the outer periphery of the optical fiber unit so that the longitudinal direction of the presser winding tape is substantially coincident with the axial direction of the optical fiber cable, and the width direction of the presser winding tape is the circumferential direction of the optical fiber cable. Wrapped vertically,
An optical fiber cable, wherein a wrap ratio, which is a wrap length in a circumferential direction of the press-wound tape, with respect to a circumferential length of the press-wound tape formed in a cylindrical shape is 50% or more.   The optical fiber cable according to claim 1, wherein the wrap portion of the press-wound tape is a non-joined portion that is not fused or bonded.   The optical fiber cable according to claim 1 or 2, wherein a reduction rate in the width direction when a tension of 50 N is applied to the press-wound tape is 10% or less. The presser winding tape is formed in a cylindrical shape in advance, and the inner diameter of the formed cylindrical body is smaller than the outer diameter of the optical fiber unit,
The cylindrical body is spread by the optical fiber unit when the optical fiber unit is inserted into the cylindrical body, and the cylindrical body and the optical fiber unit are in close contact with each other. The optical fiber cable according to any one of claims 1 to 3. The press-wrapping tape is composed of a plurality of optical fiber cores so that the longitudinal direction of the press-wrap tape substantially coincides with the axial direction of the optical fiber cable and the width direction of the press-wrap tape is the circumferential direction of the optical fiber cable. A step of vertically winding the outer periphery of the optical fiber unit;
A process of extruding and covering the outer jacket directly on the outer periphery of the press-wound tape without winding a coarse winding string;
Comprising
A method of manufacturing an optical fiber cable, wherein a wrap ratio, which is a wrap length in a circumferential direction of the press-wound tape, with respect to a peripheral length of the press-wound tape formed in a cylindrical shape is 50% or more. The step of vertically attaching the press-wound tape includes:
Rounding and heating so that the width direction of the press-wound tape is the circumferential direction, and forming a tubular body;
Opening the wrap portion of the cylindrical body, inserting the optical fiber unit therein, and then returning the cylindrical body to its original form;
Comprising
The inner diameter of the formed cylindrical body is smaller than the outer diameter of the optical fiber unit,
6. The method of manufacturing an optical fiber cable according to claim 5, wherein when the optical fiber unit is inserted into the tubular body, the tubular body is expanded by the optical fiber unit.

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