JP6605862B2 - Optical fiber cable, optical fiber cable manufacturing method, and optical fiber cable manufacturing apparatus - Google Patents

Description

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

  When water enters the inside of the optical fiber cable, the water flows in the longitudinal direction of the cable in the optical fiber cable (running water), and there is a possibility that the water reaches the connection part or branch part of the optical fiber cable. Patent Documents 1 and 2 describe disposing a string-like water-absorbing member such as a water-absorbing yarn inside the optical fiber cable in order to prevent water running in the optical fiber cable.

JP2013-088542A JP 2006-337581 A

  A string-like water-absorbing member such as a water-absorbing yarn has a small amount of water absorption by itself, and therefore it is necessary to increase the number of water-absorbing yarns in an optical fiber cable incorporating a large amount of optical fibers. However, increasing the number of water-absorbing yarns complicates the optical fiber cable manufacturing process and increases the amount of work such as exchanging and replenishing water-absorbing yarns in the manufacturing process, which increases costs.

  An object of this invention is to maintain the waterproof characteristic of an optical fiber cable, reducing the number of the water absorbing members incorporated.

A main invention for achieving the above object is to provide an optical fiber assembly in which a plurality of optical fibers are assembled, a jacket housing the optical fiber assembly, and the optical fiber so that the optical fibers face each other. An internal water-absorbing tape disposed inside the assembly, and the internal water-absorbing tape is twisted so as to turn both edges of the internal water-absorbing tape in opposite directions along the longitudinal direction of the housing space of the jacket. It is an optical fiber cable characterized by being arranged in the state.

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

  According to the optical fiber cable according to the present invention, it is possible to maintain the waterproof property of the optical fiber cable while reducing the number of built-in water absorbing members.

FIG. 1 is a cross-sectional view of an optical fiber cable. 2A to 2C are explanatory diagrams of a configuration example of the optical fiber unit 11. FIG. 3 is a perspective view of an intermittently fixed type optical fiber tape. FIG. 4A is an explanatory diagram of the arrangement of the internal water-absorbing tape 3 in the housing space of the outer jacket 2. FIG. 4B is an explanatory diagram of an existing range (existing region) of the internal water-absorbing tape 3 when viewed from the longitudinal direction. FIG. 5A is a diagram illustrating an overall configuration of a manufacturing apparatus M for manufacturing an optical fiber cable. FIG. 5B is an explanatory diagram of the rotating plate M21. 6A and 6B are explanatory diagrams of a comparative example.

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

  An optical fiber assembly in which a plurality of optical fibers are assembled, a jacket housing the optical fiber assembly, and disposed inside the optical fiber assembly so that the optical fibers face each other, An optical fiber cable characterized by comprising an internal water-absorbing tape arranged in a state twisted along the longitudinal direction of the housing accommodating space is clarified. According to such an optical fiber cable, it is possible to maintain the waterproof property of the optical fiber cable while reducing the number of built-in water absorbing members.

  The optical fiber assembly includes a plurality of optical fiber units in which a plurality of the optical fibers are bundled, and the plurality of optical fiber units are arranged in the accommodation space in a twisted state, and the internal water absorption The tape is preferably arranged between the plurality of optical fiber units. Thereby, an internal water absorption tape functions as a separator, and it becomes easy for an operator to take out a desired optical fiber unit.

  It is desirable that the optical fiber aggregate is twisted spirally in one direction, and the internal water absorbing tape is arranged in a state twisted in the one direction. Thereby, the area | region which can suppress running water with an internal water absorption tape becomes wide.

  The optical fiber assembly is preferably twisted in an SZ shape by repeatedly reversing the twist direction, and the internal water-absorbing tape is preferably arranged in a state twisted in an SZ shape by repeatedly reversing the twist direction. . This facilitates the work of taking out the optical fiber.

  The internal water-absorbing tape is preferably arranged in a state twisted by 180 degrees or more along the longitudinal direction of the housing space of the jacket. Thereby, the presence area | region of an internal water absorption tape when it sees from a longitudinal direction becomes large, and the area | region which can suppress running water becomes wide.

  The twist angle per unit length of the internal water absorbing tape is preferably 0.11 degree / mm or more. Thereby, a favorable waterproof characteristic is acquired.

  It is desirable that water absorbing powder is applied to the internal water absorbing tape. Thereby, running water in the optical fiber cable can be suppressed by the swollen water-absorbing powder.

  It is desirable that an external water-absorbing tape is wound around the outer periphery of the optical fiber assembly. Thereby, the water stop effect | action of an optical fiber cable can be improved more.

  The width of the internal water-absorbing tape is preferably smaller than the diameter of the optical fiber assembly. Thereby, the signal loss of an optical fiber can be suppressed.

  A method of manufacturing an optical fiber cable, comprising: an optical fiber assembly in which a plurality of optical fibers are aggregated; an inner water-absorbing tape; and an outer sheath that accommodates the optical fiber assembly and the inner water-absorbing tape. A step of feeding out the optical fiber and the internal water-absorbing tape, and the internal water-absorbing tape is disposed inside so that the optical fiber faces the both surfaces of the internal water-absorbing tape while twisting the internal water-absorbing tape along the longitudinal direction. And a step of forming the jacket on the outside of the optical fiber assembly in which the plurality of optical fibers are assembled. Becomes clear. According to such a manufacturing method, it is possible to manufacture an optical fiber cable having a good waterproof property while reducing the number of built-in water absorbing members.

  An optical fiber cable manufacturing apparatus comprising: an optical fiber assembly in which a plurality of optical fibers are assembled; an internal water-absorbing tape; and an outer sheath that houses the optical fiber assembly and the internal water-absorbing tape. The internal water-absorbing tape is disposed inside so that the optical fiber faces the both surfaces of the internal water-absorbing tape while twisting the internal water-absorbing tape along the longitudinal direction while sending out the optical fiber and the internal water-absorbing tape. An optical fiber cable comprising: an aggregator that collects a plurality of the optical fibers; and an extruder that forms the jacket on the outside of the optical fiber assembly in which the optical fibers are aggregated. The manufacturing apparatus will become clear. According to such a manufacturing apparatus, it is possible to manufacture an optical fiber cable having a good waterproof property while reducing the number of built-in water absorbing members.

  The aggregation machine includes a rotating plate having a first opening for inserting the internal water-absorbing tape and a plurality of second openings for inserting a plurality of optical fibers, and the first opening includes the rotating plate. While inserting the internal water-absorbing tape and rotating the rotating plate in a state where a plurality of optical fibers are inserted through the second opening, the internal water-absorbing tape is twisted along the longitudinal direction while the internal water-absorbing tape is twisted. It is desirable that the plurality of optical fibers are assembled by disposing the internal water-absorbing tape inside so that the optical fibers face both surfaces of the water-absorbing tape. Thereby, the optical fiber cable provided with the internal water absorption tape arrange | positioned in the twisted state can be manufactured.

=== First Embodiment ===
<Basic configuration of optical fiber cable>
The basic configuration of the optical fiber cable according to the present embodiment will be described below with reference to FIGS.

  FIG. 1 is a cross-sectional view of an optical fiber cable. The optical fiber cable includes an optical fiber assembly 1, a jacket 2, and an internal water absorbing tape 3. The optical fiber assembly 1 is housed in the housing space inside the outer jacket 2. As will be described later, the inner water-absorbing tape 3 is disposed inside the optical fiber assembly 1 so that both surfaces thereof face the optical fiber 1L, and is twisted along the longitudinal direction of the housing space of the outer jacket 2. Is arranged in. The outer side of the optical fiber assembly 1 is covered with an external water absorbing tape 4 that also functions as a presser winding tape, and the outer side is covered with a jacket 2. A tension member 5 (strength member) and a lip cord 6 (tear string) are embedded in the jacket 2.

  The jacket 2 is a covering material formed on the outermost layer of the optical fiber cable, and protects the optical fiber assembly 1 from the external environment. The jacket 2 accommodates the optical fiber assembly 1, the internal water absorption tape 3, and the external water absorption tape 4 in the internal storage space. The jacket 2 is made of, for example, polyvinyl chloride, polyethylene, nylon, polypropylene, or the like.

  The optical fiber assembly 1 is an assembly in which a plurality of optical fibers 1L (representing a single-core optical fiber; the same applies hereinafter) are assembled. The optical fiber assembly 1 of the present embodiment is composed of a plurality of optical fiber units 11 (11A to 11F).

  2A to 2C are explanatory diagrams of a configuration example of the optical fiber unit 11. The optical fiber unit 11 has a structure in which a bundle of optical fibers (optical fiber bundle) is bundled with a bundle material 12.

  The bundle material 12 is a member that bundles a plurality of optical fibers, and is a thread-like, string-like, or tape-like member that can bind a plurality of optical fibers. The bundle material 12 is wound around the outer periphery of the optical fiber bundle. In the optical fiber unit 11 shown in FIG. 2A, one bundle material 12 is wound spirally in one direction. However, two or more bundle members 12 may be used (see FIGS. 2B and 2C). As shown in FIGS. 2A and 2B, when the bundle material 12 is spirally wound in one direction on the outer periphery of the optical fiber bundle, when the optical fiber 1L is taken out from the optical fiber unit 11, the bundle material 12 is spiraled. It takes a long time to cut the bundle material 12, and it takes time to take out the optical fiber 1L (it takes time to unwind the bundle material 12 wound spirally). ). On the other hand, in the optical fiber unit 11 shown in FIG. 2C, the bundle material 12 is wound along the longitudinal direction of the optical fiber bundle while alternately reversing the winding direction on the outer periphery of the optical fiber bundle. It is joined to another bundle material 12 at a reversal point in the winding direction. Thereby, if the junction point at the reversal point is separated, the bundle material 12 covering the outer periphery of the optical fiber bundle in a net shape can be opened, and the optical fiber 1L can be easily taken out from the optical fiber unit 11.

  The optical fiber unit 11 is configured by bundling a plurality of intermittently fixed optical fiber tapes. FIG. 3 is a perspective view of an intermittently fixed type optical fiber tape. The intermittently fixed type optical fiber tape is an optical fiber tape in which a plurality (here, 12) of optical fibers 1L are intermittently connected in parallel. Two adjacent optical fibers 1 </ b> L are connected by a connecting portion 13. A plurality of connecting portions 13 are intermittently arranged in the longitudinal direction between two adjacent optical fibers. The plurality of connecting portions 13 of the intermittently fixed optical fiber tape are intermittently arranged two-dimensionally in the longitudinal direction and the tape width direction. A region other than the connecting portion 13 between two adjacent optical fibers is a non-connecting portion. In the unconnected portion, the two adjacent optical fibers are not restrained. As a result, the intermittently fixed optical fiber tape can be rounded into a cylindrical shape (bundle shape) or folded, and a large number of optical fibers can be bundled at high density.

  The intermittently fixed optical fiber tape is not limited to that shown in FIG. For example, the arrangement of the connecting portions 13 may be changed. Further, the number of optical fibers 1L constituting the intermittently fixed optical fiber tape may be changed. Further, the plurality of optical fibers 1L constituting the optical fiber unit 11 may not be configured by an intermittently fixed type optical fiber tape, and may be configured by bundling a plurality of single-core optical fibers 1L, for example. good.

  A plurality (six in this case) of optical fiber units 11 of the optical fiber cable shown in FIG. 1 are arranged in a housing space inside the jacket 2 in a twisted state. The plurality of optical fiber units 11 may be twisted spirally in one direction. Or the some optical fiber unit 11 may be twisted by SZ shape by repeating inversion of the twist direction by predetermined pitch. The internal water-absorbing tape 3 is twisted at a twisting pitch corresponding to the twisting pitch of the plurality of optical fiber units 11 and is disposed in a housing space inside the jacket 2 (described later).

  In FIG. 1, the optical fiber assembly 1 is constituted by an optical fiber unit 11 in which a plurality of optical fibers 1 </ b> L are bundled by a bundle material 12. However, the optical fiber assembly 1 may not be configured by the optical fiber unit 11, and may be configured by a large number of optical fibers 1 </ b> L that are not bundled by the bundle material 12. Even in this case, it is desirable that the multiple optical fibers 1 </ b> L constituting the optical fiber assembly 1 are arranged in the accommodation space inside the jacket 2 in a twisted state.

<About water absorption tape>
As shown in FIG. 1, the optical fiber cable of this embodiment includes an inner water absorbing tape 3 and an outer water absorbing tape 4.

  The internal water-absorbing tape 3 (and the external water-absorbing tape 4) is a water-absorbing member that absorbs moisture in the accommodation space inside the outer jacket 2. The internal water-absorbing tape 3 has a tape shape (including a belt shape, a sheet shape, and a flat shape), has a predetermined width, and is different from a string-like (fiber-like) water-absorbing yarn. Since the internal water-absorbing tape 3 has a wide tape shape, one internal water-absorbing tape 3 has a larger amount of water absorption than a single water-absorbing yarn.

  The internal water-absorbing tape 3 (and the external water-absorbing tape 4) has a configuration in which water-absorbing powder is attached (applied) to a tape-shaped substrate. The tape-shaped substrate is made of, for example, a nonwoven fabric made of polyester resin. In addition, the base material may have water absorption or may not have water absorption. The water-absorbing powder is a water-absorbing granular or powdery substance (water-absorbing substance). The water-absorbing powder may be adhered (applied) to the surface of the tape-shaped substrate, or may be disposed between the tape-shaped substrates composed of two nonwoven fabrics. At the time of water absorption (when the water absorption powder absorbs water), the granular or granular water absorption powder expands to become a jelly (swelling). As such water-absorbing powder, for example, a starch-based, cellulose-based, polyacrylic acid-based, polyvinyl alcohol-based, polyoxyethylene-based highly water-absorbing material having a particle diameter of 5 to 30 μm, or a mixture thereof may be used. it can. When the water-absorbing powder in the form of jelly closes the gap in the optical fiber cable, the inside of the optical fiber cable is stopped. In addition, when the water-absorbing powder swollen during running water (the water-absorbing powder that expands into a jelly shape) moves in the longitudinal direction, a gap in the optical fiber cable is closed (described later).

  As shown in FIG. 1, the internal water-absorbing tape 3 is disposed inside the optical fiber assembly 1 so that both surfaces thereof face the optical fiber 1L. Thus, the internal water-absorbing tape 3 is disposed inside the optical fiber assembly 1, so that the internal water-absorbing tape 3 can transmit water (between the optical fibers 1 </ b> L) that travels in the longitudinal direction in the optical fiber assembly 1 during running. Can be absorbed.

6A and 6B are explanatory diagrams of a comparative example. In the comparative example, as illustrated in FIG. 6A, the internal water-absorbing tape 3 ′ is not twisted but is disposed along the longitudinal direction of the housing space of the outer cover 2. In the comparative example, as shown in FIG. 6B, the region 3A ′ of the internal water-absorbing tape 3 ′ when viewed from the longitudinal direction (the internal water-absorbing tape 3 ′ is present when the internal water-absorbing tape 3 ′ is projected in the longitudinal direction). The region) is a region of the same extent as the cross-sectional shape of the internal water-absorbing tape 3 ′.
FIG. 6B shows a water stop area 3B ′ and a non-water stop area 3C ′. The water-stop region 3B ′ is a region where running water can be suppressed by the water-absorbing tape (the internal water-absorbing tape 3 and the external water-absorbing tape 4), and is a region where hatching (dot mesh) is applied in the drawing. In the comparative example, the water stop region 3B ′ is a region where the water absorption function of the water absorption tape (the internal water absorption tape 3 and the external water absorption tape 4) is effective, and is a region within a predetermined distance from the water absorption tape. In other words, the water stop region 3B ′ of the comparative example is a region where swollen water-absorbing powder is present. The non-water-stop region 3C ′ is a region where running water is difficult to suppress, and is a hatched region in the drawing. In the comparative example, the non-water-stop region 3C ′ is a region away from the water-absorbing tape by a predetermined distance or more. In the comparative example, since the internal water-absorbing tape 3 'is not twisted, the non-water-stop region 3C' exists along the longitudinal direction. As a result, the water runs in the longitudinal direction along the non-water-stop region 3C '. It becomes easy (it becomes easy to run).

FIG. 4A is an explanatory diagram of the arrangement of the internal water-absorbing tape 3 in the housing space of the outer jacket 2. As shown in the figure, the internal water-absorbing tape 3 is arranged in a state of being twisted along the longitudinal direction of the housing space of the outer jacket 2.
FIG. 4B is an explanatory diagram of an existing range (existing region) of the internal water-absorbing tape 3 when viewed from the longitudinal direction. A region 3A surrounded by a dotted line in the figure is a region where the internal water-absorbing tape 3 exists when viewed from the longitudinal direction. In other words, the region 3A is a region where the internal water-absorbing tape 3 is present when the internal water-absorbing tape 3 is projected in the longitudinal direction, and the dotted line indicating the region 3A is the internal water-absorbing tape when the internal water-absorbing tape 3 is projected in the longitudinal direction. 3 is a line showing the outer edge of the tape 3.

  As shown in FIG. 4A, since the internal water-absorbing tape 3 is arranged in a twisted state along the longitudinal direction of the housing space of the outer cover 2, as shown in FIG. The area 3 </ b> A where the water absorbing tape 3 exists is a circular area whose diameter is the width D <b> 1 of the internal water absorbing tape 3. Since the internal water-absorbing tape 3 is arranged in a state of being twisted along the longitudinal direction of the housing space of the outer jacket 2, as shown in FIG. 4B, the region 3A is a large part of the inner housing space of the outer jacket 2. Will be occupied.

  Also in this embodiment, when attention is paid to the cross section at a certain position, it corresponds to a region (non-water-stop region 3C ′ shown in FIG. 6B) that is a predetermined distance or more away from the water-absorbing tape (inner water-absorbing tape 3 and outer water-absorbing tape 4). Area) exists. However, in this embodiment, since the internal water-absorbing tape 3 is twisted and arranged along the longitudinal direction, this region (region away from the water-absorbing tape by a predetermined distance or more: non-water-stop region 3C ′ shown in FIG. 6B). The corresponding region) is formed in a spiral shape along the longitudinal direction. And for the reason (water stop mechanism) demonstrated below, the water running in the area | region (area | region equivalent to the non-water stop area | region 3C 'shown in FIG. 6B) separated from the water absorption tape more than predetermined distance is suppressed.

In the present embodiment, when water enters the housing space inside the jacket 2 of the optical fiber cable, the water absorption powder of the water absorption tape (the internal water absorption tape 3 and the external water absorption tape 4) absorbs water and expands into a jelly shape. . Further, when water is about to flow in the longitudinal direction, a part of the swollen water-absorbing powder moves along the longitudinal direction. At this time, the water-absorbing powder moved in the longitudinal direction closes a part of a region (a region corresponding to the non-water-stop region 3C ′ shown in FIG. 6B) that is a predetermined distance or more away from the internal water-absorbing tape 3 at the downstream position. That is, the swollen water-absorbing powder moved in the longitudinal direction, together with the water-absorbing powder swollen on the downstream side, closes the accommodation space inside the outer cover 2. Thereby, the optical fiber cable is stopped.
That is, paying attention to the cross section at the water-stopped position, in the region within a predetermined distance from the water-absorbing tape (region corresponding to the water-stop region 3B ′ in FIG. 6B), the water-absorbing powder in the cross-section mainly swells. The water will be stopped. Further, in the cross section, in a region (a region corresponding to the non-water-stop region 3C ′ in FIG. 6B) that is a predetermined distance or more away from the water-absorbing tape, the water-absorbing powder that has moved from the upstream side of the cross-section The water is stopped by the water absorbing powder that has moved in the direction.
Thus, in this embodiment, the internal water-absorbing tape 3 is arranged in a twisted state along the longitudinal direction, and the swollen water-absorbing powder is swollen by moving in the longitudinal direction during running. The water absorbing powder is present in the region 3A surrounded by the dotted line in FIG. 4B (the region 3A in which the internal water absorbing tape 3 is present when viewed from the longitudinal direction), and the housing space inside the jacket 2 is blocked. it can. For the above reason (water stop mechanism), in this embodiment, although there is a region (region corresponding to the non-water stop region 3C ′ shown in FIG. 6B) that is separated from the internal water-absorbing tape 3 by a predetermined distance or more, Running water in this area is suppressed.

  The twist pitch of the internal water-absorbing tape 3 is the same as the twist pitch of the optical fiber unit 11 (or the twist pitch of the optical fiber assembly 1). That is, the internal water-absorbing tape 3 is twisted together with the optical fiber unit 11. Thereby, it becomes easy to arrange | position the internal water absorption tape 3 between the optical fiber units 11 (refer FIG. 1).

  In the present embodiment, as shown in FIG. 1, the internal water-absorbing tape 3 is disposed between the optical fiber units 11 so as to separate the six optical fiber units 11 into three. Thereby, the internal water absorption tape 3 functions as a separator, and it becomes easy for an operator to take out a desired optical fiber unit 11. Moreover, it is easy to manufacture an optical fiber cable having such an arrangement (described later).

  In this embodiment, the internal water-absorbing tape 3 shown in FIG. 4A is twisted spirally in one direction. In this case, the plurality of optical fiber units 11 (or the optical fiber assembly 1) are also twisted spirally in one direction, and the internal water-absorbing tape 3 is twisted spirally in one direction together with the optical fiber unit 11. . As a result, as shown in FIG. 4B, the region 3 </ b> A of the internal water-absorbing tape 3 when viewed from the longitudinal direction becomes a circular region whose diameter is the width of the internal water-absorbing tape 3, so that the running water can be suppressed. Becomes wider.

  The internal water-absorbing tape 3 may be twisted in an SZ shape by repeatedly reversing the twist direction instead of being spirally twisted in one direction. In this case, the plurality of optical fiber units 11 (or the optical fiber aggregate 1) are also twisted in an SZ shape by repeatedly reversing the twist direction, and the internal water-absorbing tape 3 is twisted together with the optical fiber unit 11 in an SZ shape. Good to be. This facilitates the work of taking out the optical fiber 1L. When the internal water-absorbing tape 3 is arranged in a SZ-shaped state, it is desirable that the internal water-absorbing tape 3 is twisted at a twist angle of 180 degrees or more while repeatedly reversing the twist direction. Thereby, since the area 3A of the internal water-absorbing tape 3 when viewed from the longitudinal direction is a circular area having the diameter of the internal water-absorbing tape 3 as a diameter, an area where running water can be suppressed is widened. In addition, if the twist angle of the internal water-absorbing tape 3 is less than 180 degrees, the presence area 3A of the internal water-absorbing tape 3 when viewed from the longitudinal direction becomes a fan-shaped area, so that the water-stopping area may be narrowed. is there.

  Table 1 is a table showing the relationship between the twist pitch of the internal water absorbing tape 3 and the waterproof test result of the optical fiber cable. The optical fiber cable has the same configuration as that shown in FIG. 1, the outer diameter is 13 mm, the inner diameter of the jacket 2 is 8 mm, the number of the optical fiber units 11 is 6, and the optical fiber unit 11 per unit. The optical fiber 1L was a 432-fiber optical fiber cable having 72 cores. Moreover, the cross-sectional shape of the internal water absorbing tape 3 was 6 mm in width and 0.23 mm in thickness. The cross-sectional shape of the external water absorbing tape was 35 mm wide and 0.23 mm thick. The plurality of optical fiber units 11 were twisted in the SZ shape, and the internal water absorbing tape 3 was twisted in the SZ shape. The twist angle B of the internal water-absorbing tape 3 (the angle twisted while repeatedly reversing the twist direction) was 180 degrees. The twist pitch A (pitch of reversal of twist direction) of the internal water-absorbing tape 3 was changed in the range of 300 mm to 1900 mm. Each optical fiber cable is subjected to a waterproof test in conformity with IEC 60794-1-2F5, one end of a 3 m long optical fiber cable is given pressure by a 1 m water column, and water leaks from the other end after 24 hours. The presence or absence was confirmed. The waterproof property was evaluated as “× (defect)” when there was water leakage, and “◯ (good)” when there was no water leakage.

  As shown in Table 1, when the twist pitch A is 1700 mm or less (the twist angle per unit length is 0.11 degree / mm or more), the waterproof property is good. On the other hand, when the twist pitch A is 1900 mm or more (the twist angle per unit length is 0.09 degrees / mm or less), the waterproof property is poor. The reason for this is considered to be that the shorter the twist pitch A of the internal water-absorbing tape 3 is, the more easily water is stopped by the movement of the swollen water-absorbing powder in the longitudinal direction. In addition, as the twisted pitch A of the internal water-absorbing tape 3 becomes longer, the arrangement of the internal water-absorbing tape approaches the state of the comparative example (see FIGS. 6A and 6B), so even if the water-absorbing powder moves in the longitudinal direction, it contributes to water stoppage. This is thought to be difficult. For this reason, it is desirable that the twist pitch A (pitch of reversal of the twist direction) of the internal water-absorbing tape 3 is 1700 mm or less. The twist angle (= B / A) per unit length of the internal water-absorbing tape 3 is preferably 0.11 degree / mm or more.

  In the waterproof test, the internal water-absorbing tape 3 is arranged in a state of being twisted in an SZ shape. However, considering the water-stopping mechanism due to the movement of the water-absorbing powder in the longitudinal direction as described above, the internal water-absorbing tape 3 Even in the case where the screw is arranged in a spiral shape in one direction, if the twist angle per unit length of the internal water-absorbing tape 3 is 0.11 degree / mm or more, good waterproof properties can be obtained. it is conceivable that. Further, if the internal water-absorbing tape 3 is arranged in a twisted state, the twist pitch A of the internal water-absorbing tape 3 is larger than 1700 mm, and the twist angle per unit length of the internal water-absorbing tape 3 is 0. Even if it is smaller than 11 degrees / mm, it is considered that the water stopping effect is improved as compared with the comparative example (when the internal water-absorbing tape 3 is not twisted).

  As shown in FIG. 4B, the width D1 of the inner water-absorbing tape 3 is desirably smaller than the outer diameter D2 of the optical fiber assembly 1. Thereby, since the internal water absorption tape 3 can be arrange | positioned inside the optical fiber assembly 1 so that the edge of the internal water absorption tape 3 may not protrude from the optical fiber assembly 1, the edge of the internal water absorption tape 3 is not bent. It will end. If the edge of the internal water-absorbing tape 3 is bent, the optical fiber 1L receives a load from the edge of the internal water-absorbing tape 3, and the signal loss of the optical fiber 1L may increase. If the width D1 of the internal water-absorbing tape 3 is too small, the region 3A (see FIG. 4B) becomes small and the water stop action is reduced. It is preferable that it is larger than the radius of the housing space (the radius of the inner wall surface of the jacket 2).

  As shown in FIG. 1, the optical fiber cable further includes an external water absorbing tape 4. The external water-absorbing tape 4 is also a water-absorbing member that absorbs moisture in the accommodation space inside the outer cover 2, similarly to the internal water-absorbing tape 3. The external water-absorbing tape 4 also has a configuration in which water-absorbing powder is adhered (applied) to a tape-like base material, similarly to the internal water-absorbing tape 3.

  The external water-absorbing tape 4 is wound and disposed so as to cover the outer periphery of the optical fiber assembly 1. A water-absorbing tape (external water-absorbing tape 4) different from the internal water-absorbing tape 3 is wound around the outer periphery of the optical fiber assembly 1, whereby the water-stopping action of the optical fiber cable can be further enhanced.

  The external water-absorbing tape 4 has a function as a press-wound tape that prevents contact between the molten resin constituting the jacket 2 and the optical fiber 1L during the manufacture of the optical fiber cable. By constituting the presser winding tape with a water absorbing tape (external water absorbing tape 4), it is possible to suppress water running in the gap between the presser winding tape and the outer jacket 2. The external water absorbing tape 4 and the presser winding tape may be provided separately. In this case, if the external water-absorbing tape 4 is disposed between the press-winding tape and the outer cover 2 while the press-winding tape is disposed on the outer periphery of the optical fiber assembly 1, the space between the press-winding tape and the outer cover 2 is determined. It becomes possible to suppress running water in the gap. Moreover, you may manufacture an optical fiber cable, without arrange | positioning the external water absorbing tape 4, arrange | positioning a press-wound tape around the outer periphery of the optical fiber assembly 1. FIG.

  As described above, according to the present embodiment, the internal water-absorbing tape 3 of the optical fiber cable is disposed inside the optical fiber assembly 1 so that the optical fibers 1L face each other, and It arrange | positions in the state twisted along the longitudinal direction of the accommodation space. As a result, the region where the internal water-absorbing tape 3 is present (see region 3A in FIG. 4B) when viewed from the longitudinal direction is widened, so that it is easy to stop water without arranging a large number of water-absorbing yarns. For this reason, according to this embodiment, it is possible to maintain the waterproof property of an optical fiber cable, reducing the number of the water absorbing members incorporated.

  Further, according to the present embodiment, the six optical fiber units 11 are arranged in the accommodation space inside the jacket 2 in a twisted state, and the internal water-absorbing tape 3 includes three six optical fiber units 11. It arrange | positions between the optical fiber units 11 so that it may isolate | separate each. Thereby, the internal water absorption tape 3 functions as a separator, and it becomes easy for an operator to take out a desired optical fiber unit 11.

  Moreover, according to this embodiment, when the optical fiber assembly 1 is twisted spirally in one direction, the internal water-absorbing tape 3 is also unidirectional along the twist direction of the optical fiber assembly 1. It is arranged in a twisted state. As a result, as shown in FIG. 4B, the region 3 </ b> A of the internal water-absorbing tape 3 when viewed from the longitudinal direction becomes a circular region whose diameter is the width of the internal water-absorbing tape 3, so that the running water can be suppressed. Becomes wider.

  Further, when the optical fiber assembly 1 is repeatedly twisted in an SZ shape by repeatedly reversing the twisting direction, the inner water absorbing tape 3 also repeats the reversal of the twisting direction along the twisting direction of the optical fiber assembly 1. Are arranged in a state of being twisted into an SZ shape. This facilitates the work of taking out the optical fiber 1L.

<Method for manufacturing optical fiber cable>
Next, the manufacturing method of the optical fiber cable of this embodiment is demonstrated. Here, the manufacturing method of the optical fiber cable provided with the internal water absorption tape 3 twisted in SZ shape is demonstrated.

FIG. 5A is a diagram illustrating an overall configuration of a manufacturing apparatus M for manufacturing an optical fiber cable.
The optical fiber cable manufacturing apparatus M is an apparatus for manufacturing the optical fiber cable shown in FIG. 1, and includes a sending machine M1, a collecting machine M2, and an extruder M3. Each constituent member constituting the optical fiber cable is sent out in the order of the collecting machine M2 and the extruder M3 from the sending machine M1, and the optical fiber cable is manufactured.

  The sending machine M1 is a device that sends the optical fiber unit 11 and the internal water absorbing tape 3 to the collecting machine M2. The delivery machine M1 includes a supply source M1A for the internal water absorbing tape 3 and supply sources M1B to M1G for the optical fiber 1L (or the optical fiber tape shown in FIG. 3). A bundle material 12 is wound around a bundle of a plurality of optical fibers sent out from the supply sources M1B to M1G to form an optical fiber unit 11, and a plurality (here, six) of optical fiber units 11 are sent out to the collecting machine M2. It is.

  The collecting machine M2 is a device that twists the plurality of optical fiber units 11 and the internal water-absorbing tape 3 together. The collecting machine M2 has a rotating plate M21.

FIG. 5B is an explanatory diagram of the rotating plate M21.
The rotating plate M21 is a swingable member for twisting the plurality of optical fiber units 11 and the internal water-absorbing tape 3 into an SZ shape. R in the figure represents the swinging rotation direction. The rotating plate M21 has a plurality of openings M21A to M21G. The opening M21A is an opening (also referred to as “first opening” or “tape opening”) through which the internal water-absorbing tape 3 is inserted, and is a horizontally long opening along the outer shape of the internal water-absorbing tape 3 ( Through-hole). The openings M21B to M21G are also referred to as openings ("second opening", "unit opening", and "fiber bundle opening") for inserting the optical fiber unit 11 that is a bundle of a plurality of optical fibers. It is a circular opening (through hole). The opening M21A is disposed at the rotation center of the rotating plate M21, and the openings M21B to M21G are disposed so as to surround the periphery of the opening M21A. Here, the six openings M21B to M21G are arranged so as to be divided into three by the horizontally long opening M21A.

  The collecting machine M2 swings and rotates the rotating plate M21 in a state where the internal water-absorbing tape 3 is inserted through the opening M21A and the optical fiber unit 11 is inserted through the openings M21B to M21G. By rotating and rotating the rotating plate M21 with the internal water-absorbing tape 3 inserted through the opening M21A, the internal water-absorbing tape 3 is repeatedly twisted in an SZ shape by repeatedly reversing the twisting direction. Further, when the rotating plate M21 swings and rotates in a state where the optical fiber unit 11 is inserted through the openings M21B to M21G, the plurality of optical fibers 1L (optical fiber assembly 1) repeats the reversal of the twisting direction to repeat SZ. Twisted together. Further, since the openings M21B to M21G are arranged around the opening M21A, the internal water-absorbing tape 3 is arranged inside the optical fiber assembly 1 so that the optical fibers 1L face each other. It will be. The twist angle of the internal water-absorbing tape 3 can be adjusted by the rotation angle of the rotating plate M21. Further, the twist pitch (or twist angle per unit length) of the internal water-absorbing tape 3 can be adjusted by the rotational speed of the rotating plate M21 and the delivery speed of the internal water-absorbing tape 3. As described above, the collective machine M2 is configured to twist the internal water-absorbing tape 3 along the longitudinal direction, and arrange the internal water-absorbing tape 3 inside so that the optical fibers 1L face both surfaces of the internal water-absorbing tape 3. The optical fibers 1L are assembled. A plurality of optical fibers 1L (the optical fiber assembly 1 in which the internal water-absorbing tape 3 is disposed) assembled by the collecting machine M2 are sent out to the extruder M3.

  The extruder M3 is a device that forms a jacket 2 on the outside of the optical fiber assembly 1. The extruder M3 is also supplied with the external water-absorbing tape 4, the tension member 5, and the lip cord 6 together with the internal water-absorbing tape 3 and the plurality of optical fiber units 11 (optical fiber assembly 1). The extruder M3 covers the outer side of the optical fiber assembly 1 with an external water-absorbing tape 4 and extrudes a molten resin on the outer side of the external water-absorbing tape 4 so that the jacket 2 in which the tension member 5 and the lip cord 6 are embedded is formed. Form. Thereby, the optical fiber cable of this embodiment is manufactured.

  According to the above manufacturing method, since it is not necessary to send out a large number of water absorbing yarns, the manufacturing process of the optical fiber cable is simplified. Also, the amount of work for replacing or replenishing the water absorbing tape 3 can be reduced compared to the amount of work for replacing or replenishing the water absorbing yarn when a large number of water absorbing yarns are arranged, thereby reducing the cost of the optical fiber cable. Can be planned.

=== Other Embodiments ===
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.
<About the internal water absorption tape 3>
In the above embodiment, the optical fiber cable includes the single internal water absorbing tape 3. However, the internal water absorption tape with which an optical fiber cable is provided may be two or more. For example, the optical fiber cable may include a plurality of internal water-absorbing tapes by disposing a twisted internal water-absorbing tape inside each of the plurality of optical fiber units 11.

1 optical fiber assembly, 1L optical fiber, 2 jacket,
3 Internal water absorption tape, 4 External water absorption tape,
5 Tension member, 6 Lip cord,
11 optical fiber unit, 12 bundle material,
13 connecting part,
M manufacturing equipment, M1 sending machine,
M2 collecting machine, M21 rotating plate,
M3 extruder

Claims (13)

An optical fiber assembly in which a plurality of optical fibers are assembled;
A jacket housing the optical fiber assembly;
An internal water-absorbing tape disposed inside the optical fiber assembly so that the optical fibers face each other ;
With
Said internal water tape, optical fiber cable, characterized in that it is arranged in a state where the longitudinal edges of the inner water absorbing tape along was twisted to rotate in opposite directions of the envelope of the housing space . The optical fiber cable according to claim 1,
The optical fiber assembly includes a plurality of optical fiber units in which a plurality of the optical fibers are bundled,
The plurality of optical fiber units are arranged in the accommodation space in a twisted state,
The internal water-absorbing tape is disposed between the plurality of optical fiber units. The optical fiber cable according to claim 1 or 2,
The optical fiber assembly is twisted spirally in one direction,
The optical fiber cable, wherein the internal water-absorbing tape is arranged in a state twisted in the one direction. The optical fiber cable according to claim 1 or 2,
The optical fiber assembly is twisted in an SZ shape by repeatedly reversing the twist direction,
The optical fiber cable is characterized in that the internal water absorbing tape is arranged in a state of being twisted in an SZ shape by repeatedly reversing the twisting direction. An optical fiber cable according to claim 4,
The optical fiber cable is characterized in that the internal water-absorbing tape is arranged in a state twisted by 180 degrees or more along the longitudinal direction of the housing space of the jacket. An optical fiber cable according to any one of claims 1 to 5,
An optical fiber cable, wherein a twist angle per unit length of the internal water absorbing tape is 0.11 degree / mm or more. The optical fiber cable according to any one of claims 1 to 6,
An optical fiber cable, wherein water absorbing powder is applied to the internal water absorbing tape. The optical fiber cable according to claim 1,
An optical fiber cable, wherein an outer water absorbing tape is wound around the outer periphery of the optical fiber assembly. The optical fiber cable according to any one of claims 1 to 8,
An optical fiber cable, wherein a width of the internal water-absorbing tape is smaller than a diameter of the optical fiber assembly.   An optical fiber cable according to claim 9,
  The width of the internal water-absorbing tape is larger than the radius of the inner wall surface of the jacket.
An optical fiber cable characterized by that. An optical fiber assembly comprising: an optical fiber assembly in which a plurality of optical fibers are assembled; an internal water-absorbing tape; and an outer sheath that houses the optical fiber assembly and the internal water-absorbing tape,
Sending out the plurality of optical fibers and the internal water-absorbing tape;
While twisting the inner water-absorbing tape so that both edges of the inner water-absorbing tape are turned in opposite directions along the longitudinal direction, the inner water-absorbing tape is placed inside so that the optical fibers face both surfaces of the inner water-absorbing tape. Assembling a plurality of the optical fibers; and
Forming the jacket on the outside of the optical fiber assembly in which a plurality of optical fibers are assembled; and
An optical fiber cable manufacturing method comprising: An optical fiber cable manufacturing apparatus comprising an optical fiber assembly in which a plurality of optical fibers are aggregated, an internal water absorption tape, and an outer sheath that houses the optical fiber assembly and the internal water absorption tape,
A delivery device for delivering the plurality of optical fibers and the internal water-absorbing tape;
While twisting the inner water-absorbing tape so that both edges of the inner water-absorbing tape are turned in opposite directions along the longitudinal direction, the inner water-absorbing tape is placed inside so that the optical fibers face both surfaces of the inner water-absorbing tape. An aggregator that collects and arranges the plurality of optical fibers; and
An extruder for forming the jacket on the outside of the optical fiber assembly in which a plurality of optical fibers are assembled;
An optical fiber cable manufacturing apparatus comprising: An apparatus for manufacturing an optical fiber cable according to claim 12 ,
The aggregator is
A rotating plate having a first opening for inserting the internal water-absorbing tape and a plurality of second openings for inserting a plurality of optical fibers;
The internal water absorption tape is inserted into the first opening, and a plurality of optical fibers are inserted into the second opening, and the rotating plate is rotated to rotate the internal water absorption along the longitudinal direction. Twisting the inner water-absorbing tape so that both edges of the tape are turned in opposite directions, and arranging the inner water-absorbing tape inside so that the optical fibers are opposed to both surfaces of the inner water-absorbing tape. An apparatus for manufacturing an optical fiber cable, characterized in that

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