JP2019056837A - Optical fiber cable - Google Patents

Abstract

To provide an optical fiber cable capable of suppressing an increase in micro bend loss of an optical fiber conductor stored with high density.SOLUTION: A plurality of optical fiber tape conductors 120 are stored within a spacer 3 provided coaxially with a tensile strength member 4 as a center, and the outer periphery of the spacer 3 is covered with a covering 5. The spacer 3 includes an annular outer wall 32 and a barrier rib 31 provided in a diametric direction, two closed containing passages 33 that is formed by an outer wall 32 and the barrier rib 31 and store the optical fiber tape conductors 120 are provided within the spacer 3, and the containing passages 33 are formed spirally along a longitudinal direction of an optical fiber cable 1. In the optical fiber tape conductors 120, a connection part in which adjacent optical fiber conductors are connected and a non-connection part in which they are not connected are provided intermittently in a longitudinal direction between partial or all optical fiber conductors while the plurality of optical fiber conductors are being disposed in parallel.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an optical fiber cable.

Patent Document 1 describes an optical cable in which a plurality of optical fiber ribbons are housed in a spacer that is resin-molded coaxially around a strength member (tension member). The outer peripheral wall and a plurality of radial partition walls are divided into a plurality of closed storage paths that store the optical fiber ribbon, and the storage path is formed in a spiral shape.
In Patent Documents 2 and 3, an intermittently connected type in which a plurality of optical fiber strands are disposed side by side and are intermittently bonded in the longitudinal direction, and bonding portions between adjacent optical fiber strands are formed in a staggered manner. An optical fiber ribbon is described. Patent Document 2 describes a slot-type optical fiber cable in which an optical fiber unit made of an intermittently connected optical fiber ribbon is housed in a slot groove. Patent Document 3 describes a slotless optical fiber cable using the intermittently connected optical fiber ribbon.
Further, Patent Document 4 describes an optical fiber cable in which optical fiber core wires fixed by an intermittent fixing portion are densely bundled and stored in a spiral state by being twisted into a slot groove. .

JP 2012-88359 A Japanese Patent Laid-Open No. 2006-133611 JP 2016-133607 A JP 2011-100115 A

Since the optical fiber cable (optical cable) of Patent Document 1 does not require a rib structure for housing the optical fiber ribbon, the outer diameter of the spacer can be reduced and the optical fiber cable can be reduced in diameter. . However, when the optical fiber ribbon is stored at a high density, the end of the optical fiber ribbon is subjected to irregular stress from the partition wall or the outer peripheral wall, and the microbend loss increases.
Further, in the slot type optical fiber cable as in Patent Document 2, it is necessary to secure the lateral pressure resistance with the rib of the slot, so that the rib must be thickened and the storage density cannot be increased.
In addition, the slotless type optical fiber cable as disclosed in Patent Document 3 must have a resistance against side pressure with a sheath, but at the same time, a strength member must be built in the sheath. For this reason, stress concentration occurs in the strength member portion and the deformation tends to occur, so that the sheath must be made thicker and it is difficult to make the cable thin.
On the other hand, in order to increase the density of the optical fiber cable, it is known that the optical fiber core wire is stored in a twisted state (see Patent Document 4), but the twisted optical fiber unit is stored. At this time, if a large torsional strain remains in the optical fiber core wire, the optical fiber core wire tends to spread outward and is pressed against the outer wall, causing an increase in loss.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an optical fiber cable that can suppress an increase in microbend loss of an optical fiber tape core housed in a high density and can realize a reduction in diameter.

An optical fiber cable according to one aspect of the present invention is provided.
An optical fiber cable in which a plurality of optical fiber ribbons are housed in a spacer provided coaxially with a tensile member at the center, and the outer periphery of the spacer is covered with a jacket,
The spacer has an annular outer wall and a partition wall provided in a radial direction,
In the spacer, there are provided two closed storage paths that are formed by the outer wall and the partition wall and store the optical fiber ribbon, and the storage path spirals along the longitudinal direction of the optical fiber cable. Formed in a shape,
The optical fiber ribbon is a connecting portion in which a plurality of optical fibers are arranged in parallel and a part or all of the optical fibers are connected between adjacent optical fibers. And an unconnected portion in which adjacent optical fiber cores are not connected is intermittently provided in the longitudinal direction.

  According to the optical fiber cable of the above invention, it is possible to suppress the increase in microbend loss of the optical fiber ribbons housed in a high density and to realize a reduction in diameter.

It is sectional drawing which shows an example of the optical fiber cable which concerns on this embodiment. It is a figure which shows an example of the storage path currently formed in the spacer. It is a top view which shows an example of an intermittent connection type optical fiber ribbon. It is AA sectional drawing of FIG. It is a figure which shows an example of the mechanism which manufactures an optical fiber unit. It is the schematic diagram which looked at the cage of FIG. 5 from the front side. It is a figure which shows another example of the mechanism which manufactures an optical fiber unit. It is the schematic diagram which looked at the cage of FIG. 7 from the front side. It is a figure which shows an example of the manufacturing apparatus of an optical fiber cable.

(Description of Embodiment of the Present Invention)
First, embodiments of the present invention will be listed and described.
An optical fiber cable according to one aspect of the present invention is provided.
(1) An optical fiber cable in which a plurality of optical fiber ribbons are housed in a spacer provided coaxially with a tensile body as a center, and an outer periphery of the spacer is covered with a jacket;
The spacer has an annular outer wall and a partition wall provided in a radial direction,
In the spacer, there are provided two closed storage paths that are formed by the outer wall and the partition wall and store the optical fiber ribbon, and the storage path spirals along the longitudinal direction of the optical fiber cable. Formed in a shape,
The optical fiber ribbon is a connecting portion in which a plurality of optical fibers are arranged in parallel and a part or all of the optical fibers are connected between adjacent optical fibers. And an unconnected portion in which adjacent optical fiber cores are not connected is intermittently provided in the longitudinal direction.
According to the above configuration, since the optical fiber ribbon has an intermittent structure, an increase in the microbend loss of the optical fiber ribbon stored at high density can be suppressed, and a reduction in diameter can be realized.

(2) The plurality of optical fiber ribbons are assembled to constitute an optical fiber unit;
The optical fiber unit is twisted in a state where the optical fiber ribbons are twisted back along the longitudinal direction of the optical fiber cable.
The optical fiber unit may be stored in a state of being twisted back into the storage path along the longitudinal direction of the optical fiber cable.
According to the above configuration, since the optical fiber ribbons are twisted in a state where the optical fiber unit is twisted along the longitudinal direction of the optical fiber cable, the optical fiber cores cross and twist. And no twisting distortion occurs in the optical fiber core. For this reason, an optical fiber core wire does not try to spread outside, but deterioration of transmission characteristics can be suppressed.
In addition, since the optical fiber unit is stored in a spiral storage path in a twisted state, the entire optical fiber unit is not twisted. For this reason, it can prevent that an optical fiber unit spreads outside, and can suppress the deterioration of a transmission characteristic.

(3) The optical fiber unit is constituted by a secondary unit in which a plurality of primary units in which the plurality of optical fiber ribbons are collected,
The primary unit is twisted in a state where the optical fiber ribbons are twisted back along the longitudinal direction of the optical fiber cable,
The secondary unit may be twisted in a state where a plurality of the primary units are twisted back along the longitudinal direction of the optical fiber cable.
According to the above configuration, when the optical fiber unit is configured as a secondary unit in which a plurality of primary units in which a plurality of optical fiber ribbons are collected, each of the primary unit and the secondary unit is an optical unit. By twisting along the longitudinal direction of the fiber cable, the optical fiber cores and the primary units can be prevented from being twisted, and the optical fiber cores are not twisted and distorted.

(4) A plurality of the optical fiber units may be stored in the storage path.
According to the above configuration, by storing a plurality of optical fiber units in the storage path, a larger number of optical fiber ribbons can be easily stored, which is advantageous for reducing the diameter of the optical fiber cable.

(5) The plurality of optical fiber units stored in the storage path are:
It may be accommodated while changing the position in the accommodation path along the longitudinal direction of the optical fiber cable.
If the position of the optical fiber unit in the storage path does not change, the unit on the upper side of the storage path will be stored with a longer path than the unit on the bottom side of the storage path. It is necessary to make it longer than the optical fiber unit. To that end, it is necessary to prepare in advance an optical fiber unit whose length is changed according to the position (upper side, bottom side, etc.) in the storage path, and to place it at that position in the assembly (storage in the storage path) process. This complicates the manufacturing process. Further, there is a risk that a loss of disposal for discarding the extra length of the optical fiber unit may occur.
On the other hand, when a plurality of optical fiber units stored in the same storage path are stored while being replaced with each other along the longitudinal direction of the optical fiber cable, the lengths are leveled as described above. This phenomenon does not occur. For this reason, the complexity of the manufacturing process by changing the length of the optical fiber unit and the increase in the manufacturing cost due to the increase in the disposal loss of the optical fiber unit can be suppressed.

(6) The plurality of optical fiber units stored in the storage path are:
Along the longitudinal direction of the optical fiber cable, the twisting direction may be periodically changed while being twisted together and stored in the storage path.
The optical fiber units are twisted together and stored in the storage path while periodically changing the twisting direction. For example, a rotating faceplate is installed in front of the collective faceplate, and the faceplate is neutral. This can be realized by gathering while rotating in the range of ± 90 ° from the position. Thereby, since it is not necessary to rotate the whole supply bobbin which supplies an optical fiber unit, the cost of manufacturing equipment can be held down.

(7) The outer diameter of the optical fiber core wire may be not less than 125 μm and not more than 190 μm.
According to the above configuration, the optical fiber core wire can be accommodated at a high density in the optical fiber cable by making the diameter smaller than that of a general optical fiber core wire (outer diameter 250 μm).

(8) The outer diameter of the cladding of the optical fiber core wire may be not less than 80 μm and not more than 120 μm.
If the coating of the optical fiber core is thinned, the transmission characteristics of the optical fiber cable are likely to deteriorate due to adhesion of foreign matter and disconnection is likely to occur, but by reducing the outer diameter of the cladding, while ensuring the coating thickness, It becomes possible to reduce the diameter of the optical fiber core wire.

(9) The optical fiber core wire may have a loss increase of 5 dB / km or less when wound with a tension of 8 N on a bobbin obtained by winding # 240 sandpaper around a body surface having a body diameter of 280 mm.
When the diameter of the optical fiber core is reduced, the optical fiber core wire is easily bent in the optical fiber cable, and the transmission characteristics are likely to deteriorate. By using the optical fiber core wire having the above conditions, it is possible to suppress the deterioration of the transmission characteristics and realize a high-density optical fiber cable.

(Details of the embodiment of the present invention)
Specific examples of the optical fiber cable according to the embodiment of the present invention will be described below with reference to the drawings.
In addition, this invention is not limited to these illustrations, is shown by the claim, and intends that all the changes within the meaning and range equivalent to a claim are included.

FIG. 1 is a cross-sectional view showing an example of an optical fiber cable.
As shown in FIG. 1, the optical fiber cable 1 of the present example covers a spacer 3 provided coaxially with a tensile body 4 as a center, an optical fiber unit 2 accommodated in the spacer 3, and an outer periphery of the spacer 3. And a jacket 5.

  The spacer 3 has two partition walls 31 provided in the radial direction and an annular outer wall 32 connected to the outer ends of the partition walls 31. The two partition walls 31 are provided so as to extend in the opposite radial direction from the strength member 4 disposed at the center of the optical fiber cable 1.

  By the two partition walls 31 and the outer wall 32, two closed storage paths 33 (33a, 33b) capable of storing the optical fiber unit 2 are formed in the spacer 3. The storage paths 33a and 33b are formed so that the inside of the outer wall 32 is divided by the partition wall 31 so as to have the same size, for example, and a passage having a half-moon cross section is formed. The spacer 3 is formed of a resin material such as high-density polyethylene, and is formed by extrusion so that the partition wall 31 and the outer wall 32 have a thickness of 0.5 mm and an outer diameter of 4.0 mm, for example.

  The strength member 4 is composed of a plurality of (seven in this example) wires (for example, steel wires, fiber reinforced plastic wires, etc.) having resistance to tension and compression, for example. In this example, the outer periphery of the strength member 4 is covered with a resinous coating 4a so that the adhesiveness with the inner end of the partition wall 31 is enhanced. The tensile body 4 is provided along the longitudinal direction of the optical fiber cable 1.

  The jacket 5 is made of PE (polyethylene), PVC (polyvinyl chloride), or the like. The jacket 5 is formed by extrusion molding so that the thickness is, for example, 1.0 mm and the outer diameter is approximately 6.0 mm.

  As shown in FIG. 2, the partition wall 31 of the spacer 3 is formed in a spiral shape on the outer periphery of the coating 4 a of the strength member 4. Accordingly, the storage paths 33 a and 33 b formed by the partition wall 31 and the outer wall 32 are also formed in a spiral shape in one direction along the longitudinal direction of the optical fiber cable 1. 2 shows the optical fiber cable 1 in a state in which the optical fiber unit 2 is removed for easy viewing.

  As shown in FIG. 1, the optical fiber unit 2 stored in the storage path 33 includes a plurality of primary units 20 (three in this example) in which a plurality (12 in this example) of optical fiber ribbons 120 are collected. ) Formed as a collected secondary unit. The number of optical fiber ribbons 120 collected in one primary unit 20 may be two or more. If the secondary unit is composed of a plurality of primary units, one secondary unit (optical The number of primary units 20 collected in the (fiber unit) 2 may be two or more.

  The twelve optical fiber ribbons 120 included in the primary unit 20 are grouped together so that each of the optical fiber ribbons 120 extends along the longitudinal direction of the optical fiber cable 1. While being twisted, it is twisted in a spiral in one direction.

  For example, twelve optical fiber ribbons 120 are twisted right-twisted with each other. Each of the optical fiber ribbons 120 is twisted while being twisted counterclockwise, that is, twisted in the opposite direction. In this example, “twisting” refers to twisting of each optical fiber ribbon in a direction that eliminates the twist of each optical fiber ribbon that occurs when the optical fiber ribbons are twisted together. Means.

  The twelve optical fiber ribbons 120 twisted together may be bundled with an identifying bundle member 25 formed of a resin tape such as polyester. Further, the optical fiber ribbons 120 may be twisted together in an SZ shape such as a spiral in which the twisting direction is periodically reversed.

  The three primary units 20 included in the secondary unit 2 are twisted in a spiral in one direction while the primary units 20 are twisted back along the longitudinal direction of the optical fiber cable 1. In the case of the three primary units 20, as in the case of the twelve optical fiber ribbons 120, they are twisted together while being twisted. That is, the three primary units 20 are twisted together while twisting the primary units 20 generated when the primary units 20 are twisted together in such a direction that the twists are eliminated.

  The three primary units 20 twisted together may be bundled by a bundle material as described above. In addition, each primary unit 20 may be twisted together in SZ shape like the spiral which the twist direction reverses periodically, for example.

  The secondary unit 2 is stored in the storage path 33 in a state of being twisted back with respect to the storage path 33 formed in a spiral shape along the longitudinal direction of the optical fiber cable 1. That is, the secondary unit 2 is stored in the storage path 33 while twisting the secondary unit 2 generated when stored in the storage path 33 in a direction in which the twist is eliminated. In this example, four secondary units 2 are stored in the storage paths 33a and 33b, respectively. Since the primary units 20 (three primary units 20 in this example) included in the stored secondary unit 2 are twisted together, the position in the storage path 33 is changed (for example, storage) (E.g., located on the bottom side or on the upper side of the path 33).

  In this example, the secondary unit 2 in which the three primary units 20 are twisted together is housed in the housing path 33 as one optical fiber unit, but the present invention is not limited to this configuration. For example, the primary unit 20 formed by twisting a plurality of optical fiber ribbons 120 may be stored in the storage path 33 as one optical fiber unit. Moreover, the tertiary unit formed by twisting a plurality of secondary units may be accommodated.

  As shown in FIGS. 3 and 4, the optical fiber ribbon 120 is an intermittently connected optical fiber ribbon. The optical fiber ribbon 120 is adjacent to a connecting portion 122 where adjacent optical fibers 121 are connected in a state where a plurality (12 in this example) of optical fibers 121 are arranged in parallel. A non-connecting portion 123 that is not connected between the optical fiber core wires 121 is intermittently provided in the longitudinal direction. FIG. 3 shows an intermittently connected optical fiber ribbon 120 with the optical fibers 121 opened in the arrangement direction. The part where the connection part 122 and the non-connection part 123 are provided intermittently may be between some optical fiber core wires or between all optical fiber core wires.

  The optical fiber ribbon 120 is formed by intermittently applying a connecting resin 124 such as an ultraviolet curable resin or a thermosetting resin between the optical fibers to intermittently connect the connecting portion 122 and the non-connecting portion 123. It is produced as follows. In addition, by applying the connection resin 124 to the plurality of optical fiber core wires 121 and connecting all the optical fiber core wires 121, a part is cut with a rotary blade or the like to form the non-connecting portion 123. Alternatively, the intermittently connected optical fiber ribbon 120 may be manufactured.

  As shown in FIG. 4, the optical fiber core wire 121 includes, for example, a glass fiber composed of a core 121a and a clad 121b, and two coating layers (an inner coating layer 121c and an outer coating layer 121d) covering the glass fiber. It has. The covering layers 121c and 121d are made of, for example, an ultraviolet curable resin. For example, the optical fiber core 121 has an outer diameter R1 of 125 μm or more and 190 μm or less. The outer diameter R2 of the clad 121b (glass fiber) is, for example, not less than 80 μm and not more than 120 μm. The optical fiber 121 has an optical loss increase of 5 dB / km when it is wound at a tension of 8 N on a bobbin in which a sandpaper having a particle size of 240 (# 240) is wound around a body surface having a body diameter of 280 mm. It is as follows.

Next, a configuration example of a mechanism for manufacturing an optical fiber unit will be described with reference to FIGS.
FIG. 5 shows a manufacturing mechanism 40 having a configuration (cage rotation type) in which a cage 42 that houses a supply bobbin 41 is rotated when an optical fiber unit is manufactured. FIG. 6 is a schematic view of the cage 42 as viewed from the front side (right side in FIG. 5). The manufacturing mechanism 40 can manufacture the primary unit 20 by twisting the optical fiber ribbon 120, for example, and can manufacture the secondary unit 2 by twisting the primary unit 20 together.

First, the case where the primary unit 20 is manufactured using the manufacturing mechanism 40 will be described.
As shown in FIG. 5, the manufacturing mechanism 40 includes a supply bobbin 41 that feeds the optical fiber ribbon 120 and a cage 42 to which the supply bobbin 41 is attached. Further, the manufacturing mechanism 40 includes a collective plate 43 that arranges the fed optical fiber ribbon 120 at a predetermined position, and a winding drum 44 that winds up the manufactured primary unit 20.

  As shown in FIGS. 5 and 6, a plurality (12 in this example) of supply bobbins 41 are attached to the cage 42 in an annular shape coaxially with the rotation shaft 42 a of the cage 42. The number of supply bobbins 41 to be attached corresponds to the number of optical fiber ribbons 120 included in the primary unit 20. Each supply bobbin 41 rotates about the rotation shaft 41 a to send out the optical fiber ribbon 120 wound around the supply bobbin 41 to the collective plate 43.

  As the supply bobbin 41 feeds the optical fiber ribbon 120, the cage 42 rotates (rotates clockwise) in the direction of arrow B about the rotation axis 42a of the cage 42 as shown in FIG. With this rotation, the optical fiber ribbons 120 sent out from the supply bobbins 41 are twisted in a spiral in one direction. The cage 42 rotates at a predetermined speed according to the winding speed of the winding drum 44 so that the twisting pitch of the optical fiber ribbon 120 to be twisted becomes a predetermined pitch.

  As each supply bobbin 41 rotates in the arrow B direction of the cage 42, the direction of the rotation axis 41a of each supply bobbin 41 is constant (in this example, the horizontal direction) as shown in FIG. To the cage 42 in the direction of arrow C (left rotation). That is, each supply bobbin 41 rotates on the cage 42 in a direction (arrow C direction) opposite to the rotation direction (arrow B direction) of the cage 42 so that each supply bobbin 41 always faces the same direction. . By this rotation, each optical fiber tape core wire 120 when twisted is twisted back, and each optical fiber tape core wire 120 is twisted without twisting. In addition, the direction of the rotating shaft 41a of each supply bobbin 41 to be maintained is not limited to the horizontal direction, and may be maintained at another angle.

  The manufactured primary unit 20 is wound around a winding drum 44 that rotates in the direction of arrow D about the rotation shaft 44a.

Then, the case where the secondary unit 2 is manufactured using the manufacturing mechanism 40 is demonstrated.
In the case of manufacturing the secondary unit 2, in FIG. 5, the number of supply bobbins 41 (three in this example) corresponding to the number of primary units 20 included in the secondary unit 2 is attached to the cage 42. . Each supply bobbin 41 sends the wound primary unit 20 to the collective plate 43.

  As the primary unit 20 is delivered, the cage 42 rotates at a predetermined speed in the direction of arrow B as in the case of manufacturing the primary unit 20. By this rotation, the primary units 20 are twisted together in a spiral in one direction. Also, each supply bobbin 41 rotates in a direction opposite to the rotation direction of the cage 42 so that the direction of the rotation shaft 41a is maintained in a constant direction as in the case of manufacturing the primary unit 20 described above. By this rotation, each primary unit 20 is twisted back and twisted together. The manufactured secondary unit 2 is wound around the winding drum 44 in the same manner as described above. In addition, when manufacturing a tertiary unit, since a secondary unit should just be attached instead of said primary unit, the detailed description is abbreviate | omitted.

  FIG. 7 shows a manufacturing mechanism 50 having a configuration in which the winding drum 54 is rotated (winding rotary type) when manufacturing the optical fiber unit. FIG. 8 is a schematic view of the cage 52 as viewed from the front side (right side in FIG. 7). Similarly to the manufacturing mechanism 40, the manufacturing mechanism 50 can manufacture the primary unit 20 by twisting the optical fiber ribbon 120, and can manufacture the secondary unit 2 by twisting the primary unit 20. it can.

First, the case where the primary unit 20 is manufactured using the manufacturing mechanism 50 will be described.
As shown in FIG. 7, the manufacturing mechanism 50 includes a supply bobbin 51, a cage 52, a collective plate 53, and a winding drum 54, similar to the manufacturing mechanism 40.

  As shown in FIGS. 7 and 8, the supply bobbin 51 is attached to the cage 52 by the number corresponding to the number of the optical fiber ribbons 120 included in the primary unit 20, similarly to the manufacturing mechanism 40. Yes. Each supply bobbin 51 rotates around the rotation shaft 51 a to send the wound optical fiber ribbon 120 to the collective plate 53.

  The optical fiber ribbons 120 arranged at predetermined positions by the aggregate plate 53 are twisted together in a spiral in one direction by the rotation of the winding drum 54. The winding drum 54 rotates in the arrow D direction around the rotation shaft 54a, and rotates in the arrow F direction around the axis in the direction of the arrow E which is the pass line direction of the primary unit 20. By this rotation, the optical fiber ribbons 120 are rotated in the direction of arrow G in synchronization with the rotation of the take-up drum 54, and are twisted in a spiral in one direction.

  Each supply bobbin 51 rotates in the same direction as the direction of rotation of the winding drum 54 (direction of arrow F) in synchronization with the rotation of the winding drum 54 in the direction of arrow F. That is, each supply bobbin 51 rotates in a direction (arrow H direction) in which the direction of the rotation shaft 51a of each supply bobbin 51 changes with respect to the cage 52, as shown in FIG. In this case, the cage 52 does not rotate. Each supply bobbin 51 rotates around the rotation shaft 51 a while rotating in the direction of arrow H, and sends out the optical fiber ribbon 120. By this rotation, each optical fiber tape core wire 120 when twisted is twisted back, and each optical fiber tape core wire 120 is twisted without twisting.

Then, the case where the secondary unit 2 is manufactured using the manufacturing mechanism 50 is demonstrated.
When the secondary unit 2 is manufactured, the supply bobbins 51 corresponding to the number of the primary units 20 included in the secondary unit 2 are attached to the cage 52 in FIG. Each supply bobbin 51 sends the wound primary unit 20 to the collective plate 53.

  The winding drum 54 rotates in the direction of arrow D and rotates in the direction of arrow F as in the case of manufacturing the primary unit 20. By this rotation, the optical fiber ribbons 120 are twisted in a spiral in one direction. Further, each supply bobbin 51 rotates in the same direction as the rotation direction of the winding drum 54 as in the case of manufacturing the primary unit 20. By this rotation, each primary unit 20 is twisted back and twisted together. In addition, when manufacturing a tertiary unit, since a secondary unit should just be attached instead of said primary unit, the detailed description is abbreviate | omitted.

Next, an example of an apparatus for manufacturing the optical fiber cable 1 will be described with reference to FIG.
As shown in FIG. 9, the manufacturing apparatus 60 of the optical fiber cable 1 includes a feeding bobbin 70 for feeding out the tensile body 4, a cage 62, a supply bobbin 61 accommodated in the cage 62, and a twisting direction of the optical fiber unit 2. Is provided with a twisted plate 65 that can be periodically changed. Further, the manufacturing apparatus 60 includes a spacer molding machine 66, a collective plate 63 provided in the spacer molding machine 66, a spacer cooler 67, and a winding drum 64.

The feeding bobbin 70 is rotated in the direction of arrow I about the rotation shaft 70 a to send the tensile strength body 4 toward the spacer molding machine 66.
In this example, the secondary unit 2 manufactured by the manufacturing mechanism of FIG. 5 or FIG. 7 is wound around each supply bobbin 61. Each cage 62 is provided with a number of supply bobbins 61 corresponding to the number of secondary units 2 stored in the storage paths 33 a and 33 b of the spacer 3. Each supply bobbin 61 sends the secondary unit 2 to the twisting plate 65 by rotating around the rotation shaft 61a.

  The twist plate 65 is formed with a plurality of holes through which the secondary units 2 sent from the supply bobbin 61 pass. For example, the twisting plate 65 is reversely rotated within a range of ± 90 ° from the neutral position, thereby twisting the secondary units 2 passing through the twisting plate 65 with each other while periodically changing the twisting direction (SZ twisting). ). The SZ-twisted secondary unit 2 is sent out from the twist plate 65 toward the spacer forming machine 66.

  The tensile body 4 and the secondary unit 2 are respectively arranged at predetermined positions by the aggregate plate 63 and supplied to the spacer molding machine 66. The spacer molding machine 66 is provided with a rotary crosshead, and the spacer 3 including the annular outer wall 32 and the spiral partition wall 31 is extruded and formed around the strength member 4, and the storage path 33 for the spacer 3. The secondary unit 2 twisted in SZ is housed inside. The secondary units 2 are stored while changing positions in the storage path 33 by being twisted together.

  The spacer 3 in which the secondary unit 2 is accommodated is cooled and cured by the spacer cooler 67. The cured spacer 3 is formed by extruding the outer cover 5 on the outer periphery of the spacer 3 by a jacket molding machine (not shown), and subsequently cured by a jacket cooler (not shown). The cable 1 is wound around a winding drum 64.

  In addition, although this example demonstrated the structure which twists the secondary unit 2 accommodated in the storage path 33 by SZ, it is not limited to this. For example, the secondary units 2 stored in the storage path 33 may be twisted in a spiral in one direction while being twisted back. In that case, each supply bobbin 61 can be turned back by rotating in the same direction as the spiral of the storage path and rotating each bobbin in the opposite direction. In this case, the secondary units 2 are stored while changing their positions in the storage path 33 (for example, positioned on the bottom side or the upper side of the storage path 33).

  According to the optical fiber cable 1 as described above, the intermittent connection type optical fiber ribbon 120 is accommodated in the accommodation path 33 of the spacer 3. For this reason, since the shape of the optical fiber ribbon 120 in the cross section of the storage path can be freely changed, the optical fiber ribbon 120 in the storage path 33 is higher than that of the optical fiber tape that is not intermittently connected. It becomes possible to store in the density. Therefore, an increase in the microbend loss of the optical fiber ribbon 120 stored at a high density can be suppressed, and the outer diameter of the optical fiber cable 1 can be reduced.

  The secondary unit 2 is twisted in a state where the primary units 20 are twisted back along the longitudinal direction of the optical fiber cable 1. For this reason, it is possible to prevent the primary units 20 from crossing and twisting. The primary unit 20 is twisted in a state where the optical fiber ribbons 120 are twisted back along the longitudinal direction of the optical fiber cable 1. For this reason, it can prevent that the optical fiber tape core wires 120 cross | intersect and a twist arises. Accordingly, since the optical fiber core wire 121 constituting the optical fiber tape core wire 120 is not twisted and strained, the twisted optical fiber core wire 121 does not try to spread outside, and the microbend loss is increased. Can be suppressed.

  In addition, since the secondary unit 2 is stored in a twisted state with respect to the storage path 33 formed in a spiral shape, the secondary unit 2 is not twisted. For this reason, since the repulsive force which tries to release torsion is not generated in the stored secondary unit 2, irregular stress is applied to the optical fiber core wire 121 from the inner wall of the storage path 33. There is no. Therefore, an increase in the microbend loss of the optical fiber core wire 121 can be suppressed, and the outer diameter of the optical fiber cable 1 can be reduced. Moreover, the yield in the process of manufacturing the optical fiber cable 1 can be improved, and the manufacturing cost can be reduced.

A plurality of secondary units 2 stored in the storage path 33 are stored in the storage path 33 while changing their positions with each other along the longitudinal direction of the optical fiber cable 1.
If the position of the optical fiber unit in the storage path does not change, for example, the unit on the upper side of the storage path is stored with a longer path than the unit on the bottom side of the storage path. It must be longer than the optical fiber unit on the side. To that end, it is necessary to prepare in advance an optical fiber unit whose length is changed according to the position (upper side, bottom side, etc.) in the storage path, and to place it at that position in the assembly (storage in the storage path) process. This complicates the manufacturing process. Further, there is a risk that a loss of disposal for discarding the extra length of the optical fiber unit may occur.
Therefore, the length of the secondary unit 2 can be leveled by storing the optical fiber cable 1 while exchanging its position, and the above phenomenon can be prevented from occurring. As a result, it is possible to prevent the manufacturing process from becoming complicated, to prevent the secondary unit 2 from being discarded, and to reduce the manufacturing cost.

  Further, by using the twisting plate 65, the secondary units 2 can be twisted together and stored in the storage path 33 while periodically changing the twisting direction of the secondary units 2. Therefore, the secondary units 2 can be twisted together by reversing and rotating the twisting plate 65 without rotating the large cage 62 in which a large number of supply bobbins 61 are accommodated. Therefore, even when a cable having a large number of optical fiber ribbons 120 to be accommodated is manufactured, the manufacturing apparatus 60 can be prevented from increasing in size, and the manufacturing cost can be reduced.

  Further, the optical fiber core 121 is accommodated in the optical fiber cable 1 at a high density by making the outer diameter R1 of the optical fiber core 121 smaller than that of a general optical fiber (outer diameter 250 μm). be able to. However, in this case, if the coating of the optical fiber core wire 121 is thinned, the transmission characteristics of the optical fiber cable 1 are likely to deteriorate or break due to the adhesion of foreign matter. Therefore, by reducing the outer diameter R2 of the clad 121b, it is possible to reduce the diameter of the optical fiber core wire 121 while ensuring the coating thickness, and the optical fiber core wire 121 is increased in the optical fiber cable 1. Can be stored in density.

  Further, when the diameter of the optical fiber core 121 is reduced, the optical fiber core 121 is likely to bend in the optical fiber cable 1 and transmission characteristics are likely to deteriorate. On the other hand, since the optical fiber core wire 121 of the present example has the above-described microbend resistance property, it is possible to realize the high-density optical fiber cable 1 while suppressing the deterioration of the transmission property. .

  While the invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention. In addition, the number, position, shape, and the like of the constituent members described above are not limited to the above-described embodiments, and can be changed to a number, position, shape, and the like that are suitable for carrying out the present invention.

1: Optical fiber cable 2: Optical fiber unit (secondary unit)
3: Spacer 4: Tensile body 4a: Cover 5: Outer jacket 20: Primary unit 31: Partition wall 32: Outer wall 33 (33a, 33b): Storage path 40, 50: Manufacturing mechanism 41, 51, 61: Supply bobbin 42, 52 62: Cage 43, 53, 63: Collecting plate 44, 54, 64: Winding drum 60: Manufacturing device 65: Twist plate 66: Spacer molding machine 70: Feeding bobbin 120: Optical fiber ribbon 121: Light Fiber core wire 121a: Core 121b: Cladding 122: Connection portion 123: Non-connection portion

Claims (9)

An optical fiber cable in which a plurality of optical fiber ribbons are housed in a spacer provided coaxially with a tensile member at the center, and the outer periphery of the spacer is covered with a jacket,
The spacer has an annular outer wall and a partition wall provided in a radial direction,
In the spacer, there are provided two closed storage paths that are formed by the outer wall and the partition wall and store the optical fiber ribbon, and the storage path spirals along the longitudinal direction of the optical fiber cable. Formed in a shape,
The optical fiber ribbon is a connecting portion in which a plurality of optical fibers are arranged in parallel and a part or all of the optical fibers are connected between adjacent optical fibers. And a non-connecting portion that is not connected between adjacent optical fiber core wires is intermittently provided in the longitudinal direction,
Fiber optic cable. The plurality of optical fiber ribbons are assembled to constitute an optical fiber unit,
The optical fiber unit is twisted in a state where the optical fiber ribbons are twisted back along the longitudinal direction of the optical fiber cable.
The optical fiber unit is stored in a state of being twisted back into the storage path along the longitudinal direction of the optical fiber cable.
The optical fiber cable according to claim 1. The optical fiber unit is constituted by a secondary unit in which a plurality of primary units in which the plurality of optical fiber ribbons are collected,
The primary unit is twisted in a state where the optical fiber ribbons are twisted back along the longitudinal direction of the optical fiber cable,
The secondary unit is twisted in a state in which the plurality of primary units are twisted back along the longitudinal direction of the optical fiber cable.
The optical fiber cable according to claim 2. A plurality of the optical fiber units are stored in the storage path.
The optical fiber cable according to claim 2 or claim 3. The plurality of optical fiber units stored in the storage path are:
Along the longitudinal direction of the optical fiber cable, it is stored while changing the position in the storage path,
The optical fiber cable according to claim 4. The plurality of optical fiber units stored in the storage path are:
Along the longitudinal direction of the optical fiber cable, while periodically changing the twisting direction, are twisted together and stored in the storage path,
The optical fiber cable according to claim 5. The outer diameter of the optical fiber is 125 μm or more and 190 μm or less,
The optical fiber cable according to any one of claims 1 to 6. The outer diameter of the cladding of the optical fiber core wire is not less than 80 μm and not more than 120 μm,
The optical fiber cable according to any one of claims 1 to 7. The optical fiber core wire has an increase in loss of 5 dB / km or less when it is wound around a bobbin in which # 240 sandpaper is wound around a body surface having a body diameter of 280 mm with a tension of 8 N.
The optical fiber cable according to any one of claims 1 to 8.

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