JP2014228821A - Optical fiber cable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical fiber cable that can reduce the diameter, reduce the directional property of a curve of the cable, and prevent induction.SOLUTION: The optical fiber cable includes: a cable core 1 including one or more optical fibers; a band-like tensile strength body 3 made of fiber-reinforced plastic deformed so as to accommodate the cable core 1; and a jacket 4 covering the outer periphery of the tensile strength body 3. The tensile strength body 3 includes a presser coil 2 that is curved in a U shape or C shape so as to accommodate the cable core 1 and is vertically wound so as to cover the opening of the U shape or C shape.

Description

  The present invention relates to a slot type optical fiber cable.

  Conventionally, a slot-type optical fiber cable having a slot portion for accommodating an optical fiber is known in order to improve the intermediate post-branch property of the fiber cable (see, for example, Patent Documents 1 to 3).

Japanese Patent No. 4891870 JP 2009-229786 A JP 2004-117675 A

  However, in the optical fiber cable described in Patent Document 1, since one strength member and one rigid straight member are embedded in the sheath with the optical fiber interposed therebetween, the cable has a bending directionality. For this reason, it may be difficult to work in a hand hole or on a pillar. Furthermore, when a steel wire is used for the tension member, the cable becomes a dielectric, which may affect the characteristics of other metal cables. On the other hand, when fiber reinforced plastic (FRP) is used for the tension member, an FRP having a larger outer diameter is required in order to obtain a Young's modulus equivalent to that of a steel wire in consideration of cable characteristics. Therefore, the outer diameter of the cable is increased.

  Moreover, in the optical fiber cable described in Patent Document 2, FRP that is curved in advance is used. When such a curved FRP is bobbin-wound, there is a problem that the winding diameter is remarkably increased as compared with a non-curved belt-like FRP, or it is easily deformed due to winding tension or drop of winding.

  Further, in the optical fiber cable described in Patent Document 3, the resin constituting the outer sheath wraps around the opening of the tape-shaped tensile strength member toward the optical fiber, and the extra portion of the optical fiber accompanying the shrinkage of the outer sheath at a low temperature. In some cases, it is not possible to secure a space that can sufficiently absorb the long generation, and the transmission loss of the optical fiber is deteriorated.

  In view of the above problems, an object of the present invention is to provide an optical fiber cable that can be reduced in diameter, can reduce the direction of bending of the cable, and can be non-inductive.

  According to one aspect of the present invention, an optical fiber comprising an optical fiber, a belt-shaped tensile member made of fiber-reinforced plastic deformed so as to accommodate the optical fiber, and a jacket covering the outer periphery of the tensile member. A cable is provided.

  In one embodiment of the present invention, a presser winding that covers the outer periphery of the optical fiber may be further provided.

  In one embodiment of the present invention, the fiber reinforced plastic may be an aramid fiber reinforced plastic or a glass fiber reinforced plastic.

  In one embodiment of the present invention, a tear string vertically attached to the outer periphery of the strength member may be further provided.

  In one embodiment of the present invention, at least a part of the outer peripheral surface of the strength member may be bonded to the outer cover with an adhesive.

  In one embodiment of the present invention, the strength member is curved in a U-shape or C-shape so as to accommodate the optical fiber, has an opening between both ends, and is vertically attached to cover the opening. A winding tape may be further provided.

  In one embodiment of the present invention, the strength member is curved in a U shape or a C shape so as to accommodate the optical fiber, and has a first member having an opening between both ends, and a second member covering the opening. And a member.

  In one embodiment of the present invention, the strength member may be deformed into a cylindrical shape so that both ends thereof are in contact with each other.

  ADVANTAGE OF THE INVENTION According to this invention, the optical fiber cable which can achieve diameter reduction, can reduce the directionality of the bending of a cable, and can be made non-inductive can be provided.

It is sectional drawing perpendicular | vertical to a longitudinal direction which shows an example of the optical fiber cable which concerns on embodiment of this invention. It is sectional drawing perpendicular | vertical to a longitudinal direction which shows an example of the optical fiber cable which concerns on other embodiment of this invention. It is sectional drawing perpendicular | vertical to a longitudinal direction which shows another example of the optical fiber cable which concerns on other embodiment of this invention. It is sectional drawing perpendicular | vertical to a longitudinal direction which shows another example of the optical fiber cable which concerns on other embodiment of this invention. It is sectional drawing perpendicular | vertical to a longitudinal direction which shows another example of the optical fiber cable which concerns on other embodiment of this invention.

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

  An optical fiber cable comprising: an optical fiber; a belt-shaped tensile body made of fiber-reinforced plastic deformed so as to accommodate the optical fiber; and a jacket covering an outer periphery of the tensile body. Become. With such an optical fiber cable, the diameter can be reduced, the direction of bending of the cable can be reduced, and non-induction can be achieved.

  In the optical fiber cable, it is desirable to further include a presser winding that covers the outer periphery of the optical fiber. Thereby, it is possible to prevent the optical fiber from being broken.

  The fiber reinforced plastic is desirably an aramid fiber reinforced plastic or a glass fiber reinforced plastic. Thereby, a strip | belt-shaped tension body can be deform | transformed so that an optical fiber may be accommodated inside.

  Moreover, it is desirable to further provide a tear string vertically attached to the outer periphery of the strength member. Thereby, a tear string can be pulled in the case of an intermediate back branch, and a jacket can be divided | segmented.

  Moreover, it is desirable that at least a part of the outer peripheral surface of the strength member is bonded to the outer cover with an adhesive. Thereby, the protrusion of the strength member due to the contraction of the jacket can be prevented.

  Further, the strength member is further provided with a press-wound tape that is curved in a U shape or a C shape so as to accommodate the optical fiber, has an opening between both ends, and is vertically attached to cover the opening. It is desirable. Thereby, it is possible to prevent the resin from entering the inside of the tensile body during the extrusion molding of the jacket.

  Further, the strength member includes a first member that is curved in a U shape or a C shape so as to accommodate the optical fiber, and has an opening between both ends, and a second member that covers the opening. Is desirable. Thereby, it is possible to prevent the resin from entering the inside of the tensile body during the extrusion molding of the jacket.

  Further, it is desirable that the tensile body is deformed into a cylindrical shape so that both ends thereof are in contact with each other. Thereby, it is possible to prevent the resin from entering the inside of the tensile body during the extrusion molding of the jacket.

  Next, embodiments of the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals.

  As shown in FIG. 1, an optical fiber cable according to an embodiment of the present invention includes a cable core 1 having at least one optical fiber and a fiber reinforced plastic deformed so as to accommodate the cable core 1 inside. A belt-like strength member (tension member) 3 and a jacket (sheath) 4 covering the outer periphery of the strength member 3 are provided.

  The number and type of optical fibers included in the cable core 1 are not particularly limited. The cable core 1 is configured by, for example, collecting 100 to 200 optical fiber cores having a diameter of 0.25 mm. As the optical fiber, a core wire such as an optical fiber strand, an optical fiber core wire, or an optical fiber tape core wire can be adopted. Among these, as the optical fiber ribbon, an intermittently fixed ribbon or the like can be used. Further, when having a plurality of optical fibers, they may be stretched in parallel without being twisted in the longitudinal direction, may be twisted in one direction, may be twisted in an SZ shape, and may be twisted in one direction. You may hold | maintain the composite shape which SZ twist changes in the middle.

  A presser winding 2 made of a plastic film is disposed so as to cover the outer periphery of the cable core 1. The cable core 1 and the presser winding 2 constitute an optical fiber unit. As the presser winding 2, instead of covering with a plastic film, bunching may be spirally formed with a thread or tape. The material of the presser winding 2 is a thermoplastic resin such as polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT) or nylon (registered trademark), or a thermosetting resin such as epoxy. Can be used. The presser winding 2 can prevent the optical fiber from being broken. Note that the optical fiber cable according to the embodiment of the present invention may not have the presser winding 2.

  The tensile body 3 is formed by deforming a band-shaped FRP having a rectangular cross section when mounted in a cable, and has a U-shaped (groove-shaped) or C-shaped cross-sectional shape. The strength member 3 serves as a so-called slot portion that accommodates the cable core 1 inside, and also serves to prevent the optical fiber from being damaged by a tension or the like that acts when the cable is laid or a temperature change caused after the laying. Have. As the FRP constituting the strength member 3, an aramid fiber reinforced plastic (AFRP) reinforced with an aramid fiber such as Kevlar (registered trademark), a glass fiber reinforced plastic (GFRP), or the like can be used.

  The thickness of the strength member 3 is about 0.7 mm to 1.5 mm. The thickness of the strength member 3 is preferably 1.0 mm or less from the viewpoint of maintaining ease of bending and preventing the return after the covering 4 is coated.

  A pair of tear strings 5 a and 5 b (lip cords) are vertically attached to the outer periphery of the strength member 3. The tear strings 5a and 5b are made of a twisted yarn made of polyester, a fiber string such as an aramid fiber or glass fiber, or the like.

  A press-wound tape 8 is vertically attached so as to cover the opening 7 of the strength member 3. The material of the presser winding tape 8 is a thermoplastic resin such as polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT) or nylon (registered trademark), or thermosetting such as epoxy. Resin can be used. The presser winding tape 8 can prevent the resin from entering the inside of the tensile body 3 when the outer cover 4 is extruded.

  As the material of the jacket 4, a resin such as polyvinyl chloride (PVC), polyethylene (PE), nylon (registered trademark), fluorinated ethylene, or polypropylene (PP) can be used. Color bands 6a and 6b are provided on the surface portion of the jacket 4 corresponding to the positions of the tear strings 5a and 5b so that the positions of the tear strings 5a and 5b can be recognized. The color bands 6a and 6b are made of colored resin or the like, and are provided in parallel with the tear strings 5a and 5b in the cable longitudinal direction.

  At the time of intermediate post branching of the optical fiber cable according to the embodiment of the present invention, a portion provided with the color bands 6a and 6b of the outer cover 4 is shaved using a knife or a cutter, and the tear strings 5a and 5b are pulled out. And the tear strings 5a and 5b are pulled, and the outer jacket 4 is divided. The jacket 4 is opened, the holding tape 8 is peeled off, and the cable core 1 and the optical fiber are taken out from the opening 7 of the strength member 3. At this time, the opening of the strength member 3 is opened by the restoring force (repulsive force) of the deformed strength member 3 to return to the belt shape, so that the cable core 1 and the optical fiber can be easily taken out.

  According to the optical fiber cable according to the embodiment of the present invention, the strength member 3 serves as the original strength member as well as the slot portion that accommodates the cable core 1. There is no need to mount a tensile body, and the cable can be made thinner.

  Furthermore, FRP is used as the tensile body 3, and a metal material such as a steel wire is not used. For this reason, there is no metal part in the whole optical fiber cable, and it can be made non-inductive.

  Furthermore, since the strength member 3 has a U-shaped or C-shaped cross-sectional shape, the direction of the bending of the cable is suppressed as compared with a case where a pair of strength members are embedded with an optical fiber interposed therebetween. Can do.

  Furthermore, when the optical fiber cable is branched after the middle, the opening 7 is opened by a repulsive force that the tensile body 3 tries to return to a belt shape, so that the optical fiber can be easily taken out from the inside of the tensile body 3.

  As an example of a method for manufacturing an optical fiber cable according to an embodiment of the present invention, an optical fiber, a tear string 5a, 5b, and a presser winding while bending a band-shaped strength member 3 made of FRP by passing through a slit. 2. It introduce | transduces into the extruder (nipple) which abbreviate | omitted illustration with the press winding tape 8. FIG. Extruder heat of about 170 ° C. to 210 ° C. is applied to the strength member 3 when passing through the slit. Then, the resin is coated and extruded, and the strength member 3 is covered with the outer cover 4 while being curved. At this time, the presser winding tape 8 can prevent the resin from entering the inside of the strength member 3 when the outer cover 4 is extruded.

  According to the method of manufacturing an optical fiber cable according to the embodiment of the present invention, since the strength member 3 has both the function of the slot portion and the function as the original strength member, the jacket 4 and the slot portion are individually provided. No need to extrude. Therefore, it is not necessary to prepare two extruders, and the cost of capital investment can be reduced.

(Example)
As an example of the optical fiber cable according to the embodiment of the present invention, an optical fiber, a tear string, a plastic film, a press roll tape and an extruder (nipple) while bending a GFRP having a thickness of 1.5 mm and a width of 15 mm. ), And a 60-fiber optical fiber cable with an outer diameter of 9.0 mm was prototyped. A color band was added to the position on the jacket corresponding to the position of the tear string.

  The prototype optical fiber cable was evaluated for handling properties, transmission characteristics, and intermediate post branching properties. First, for handling properties, the cable was rounded with a diameter of 200 mm, and the presence or absence of abnormality was confirmed. As a result, it was possible to wind up without any problem and no abnormality was confirmed, so it was confirmed that the film had good handling properties.

  Next, regarding the transmission characteristics, optical loss measurement was performed on the cable 1000 m using an OTDR (Optical Time Domain Reflectometer). The transmission loss was 0.198 dB / km at a measurement wavelength of 1.55 μm, and it was confirmed that the film had good transmission characteristics.

  Next, with respect to the intermediate post-branching property, the loss fluctuation until the target optical fiber core wire was taken out was measured after performing the intermediate post-branching. As a result, it was confirmed that the measurement wavelength was 0.1 dB / heart or less at a wavelength of 1.55 μm and a good intermediate post-branching property was obtained.

(Other embodiments)
As described above, the present invention has been described according to the embodiment. However, it should not be understood that the description and drawings constituting a part of this disclosure limit the present invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art.

  For example, as shown in FIG. 2, the strength member 3 is deformed so as to accommodate the cable core 1 and covers the first member 3a having an opening between both ends and the opening of the first member 3a. And the second member 3b arranged as described above. The first member 3a and the second member 3b form a cylindrical shape. In this case, even if the press-wound tape 8 shown in FIG. 1 is not provided, it is possible to prevent the resin from entering the inside of the strength member 3 when the outer cover 4 is extruded.

  Moreover, when arrange | positioning in a closure etc., the protrusion of the tension | tensile_strength body 3 from a cable terminal generate | occur | produces by contraction of the jacket 4, and problems, such as a fiber disconnection, may arise. Therefore, as shown in FIG. 3, at least a part of the outer peripheral surface of the strength member 3 may be bonded to the outer cover 4 and the adhesive layer 9 to such an extent that the intermediate post-branching property is not hindered. Protrusion of the strength member 3 due to contraction of the outer jacket 4 can be prevented.

  Further, as shown in FIG. 4, the strength member 3 may be deformed into a cylindrical shape so that both ends of the strength member 3 are in contact with each other. In this case, even if the press-wound tape 8 shown in FIG. 1 is not provided, it is possible to prevent the resin from entering the inside of the strength member 3 when the outer cover 4 is extruded.

  Further, as shown in FIG. 5, protrusions 10 a and 10 b extending in the cable longitudinal direction may be provided on the jacket 4 instead of the color bands 6 a and 6 b shown in FIG. 1. The positions of the tear strings 5a and 5b can be recognized by the protrusions 10a and 10b. The number of the protrusions 10a and 10b is not particularly limited.

  As described above, the present invention naturally includes various embodiments not described herein. Therefore, the technical scope of the present invention is defined only by the invention specifying matters according to the scope of claims reasonable from the above description.

1 ... Cable core 2 ... Presser winding (plastic film)
DESCRIPTION OF SYMBOLS 3 ... Strength body 3a ... 1st member 3b ... 2nd member 4 ... Jacket | cover 5a, 5b ... Tear string 6a, 6b ... Color belt 8 ... Pressing winding tape 9 ... Adhesive layer 10a, 10b ... Protrusion

Claims (8)

Optical fiber,
A belt-shaped tensile member made of fiber-reinforced plastic deformed so as to accommodate the optical fiber inside;
An optical fiber cable comprising: a jacket covering an outer periphery of the strength member.   The optical fiber cable according to claim 1, further comprising a press winding covering an outer periphery of the optical fiber.   The optical fiber cable according to claim 1 or 2, wherein the fiber reinforced plastic is an aramid fiber reinforced plastic or a glass fiber reinforced plastic.   The optical fiber cable according to any one of claims 1 to 3, further comprising a tear string vertically attached to an outer periphery of the strength member.   The optical fiber cable according to any one of claims 1 to 4, wherein at least a part of an outer peripheral surface of the tensile strength body is bonded to the jacket with an adhesive. The tensile body is curved in a U-shape or C-shape so as to accommodate the optical fiber, and has openings between both ends;
The optical fiber cable according to claim 1, further comprising a press-wound tape vertically attached so as to cover the opening. The tensile body is
A first member curved in a U-shape or C-shape to accommodate the optical fiber, and having an opening between both ends;
The optical fiber cable according to claim 1, further comprising a second member that covers the opening.   The optical fiber cable according to any one of claims 1 to 4, wherein the tensile body is deformed into a cylindrical shape so that both ends thereof are in contact with each other.

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