JP6150422B2 - Fiber optic cable - Google Patents

Description

  The present invention relates to a slotless optical fiber cable.

  As a cable structure for realizing a reduction in the diameter and density of an optical fiber cable, a slotless, optical fiber unit is formed by bundling a plurality of optical fiber core wires with a bundle material, and an assembly of optical fiber units In order to improve performance, a structure has been proposed in which presser winding is applied to the outer periphery and the outside is covered with a cable jacket (see, for example, Patent Document 1).

  However, when an optical fiber cable is installed, the optical fiber core wire moves in the longitudinal direction due to various factors such as installation conditions and the environment after installation, and the end of the optical fiber core wire is the end of the cable. There is a risk that the cable connection workability may be hindered due to the movement of the core wire that protrudes or becomes swallowed.

  As a measure for preventing such core wire movement, a structure in which a cured resin is enclosed in a slot groove in a slot-type optical fiber cable has been proposed (for example, see Patent Document 2). Moreover, the structure which gave the tape which impregnated the adhesive agent was proposed (for example, refer patent document 3).

JP 2009-237341 A JP-A-10-206707 JP 2003-241037 A

  However, in the slot structure described in Patent Document 2, it was possible to enclose the curable resin in the groove. However, in the slotless type, since there is no groove in the structure, it is difficult to encapsulate the curable resin. It cannot be applied to the reduction in diameter and density of a cable using a mold structure.

  In the structure described in Patent Document 3, the tape impregnated with the adhesive is formed by applying two types of tapes having different fluidity and further covering with a jacket. For this reason, there are concerns about the complexity of the line, the distinction of the adhesive tape, and the problems in terms of cost.

  In view of the above problems, an object of the present invention is to provide a slotless optical fiber cable that can suppress the movement of the optical fiber in the longitudinal direction of the cable and can suppress the deterioration of workability during connection work. To provide a fiber cable.

  According to one aspect of the present invention, a plurality of optical fibers twisted together, a press-winding tape that covers the periphery of the plurality of optical fibers, and a plurality of optical fibers and the press-winding tape in the longitudinal direction of the cable. An optical fiber cable is provided that includes a string-like body that is provided along a straight line and coated with an ultraviolet curable resin, and a jacket that covers the periphery of the presser tape.

  In one embodiment of the present invention, a pair of strength members embedded in a jacket may be further provided, and the string-like body may be disposed on a straight line connecting the pair of strength members.

  In one embodiment of the present invention, the coating thickness of the ultraviolet curable resin coated on the string may be 0.1 mm to 0.5 mm.

  In one embodiment of the present invention, the elastic modulus of the ultraviolet curable resin coated on the string may be 0.83 MPa to 1.30 MPa.

  In one embodiment of the present invention, a plurality of optical fibers may be twisted in the SZ direction, the twist pitch may be 300 mm to 1000 mm, and the twist angle may be 180 ° to 360 °.

  According to the present invention, in a slotless optical fiber cable, it is possible to provide an optical fiber cable that can suppress the movement of the optical fiber in the longitudinal direction of the cable and can suppress the deterioration of workability during the connection work. Can do.

It is sectional drawing perpendicular | vertical to the cable longitudinal direction which shows an example of the optical fiber cable which concerns on embodiment of this invention. It is the schematic which shows an example of the optical fiber which concerns on embodiment of this invention, and a string-like body. It is the schematic which shows another example of the optical fiber which concerns on embodiment of this invention, and a string-like body. It is sectional drawing perpendicular | vertical to the cable longitudinal direction of the string-like body which concerns on embodiment of this invention. It is the schematic which shows an example of the manufacturing apparatus of the optical fiber cable which concerns on embodiment of this invention. It is a table | surface showing the evaluation result 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.

  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. However, it should be noted that the drawings are schematic, and the relationship between the thickness and the planar dimensions, the ratio of the thickness of each layer, and the like are different from the actual ones. Therefore, specific thicknesses and dimensions should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

  Further, the embodiments described below exemplify apparatuses and methods for embodying the technical idea of the present invention, and the technical idea of the present invention includes the material, shape, structure, The layout is not specified as follows. The technical idea of the present invention can be variously modified within the scope of the claims.

(Structure of optical fiber cable)
As shown in FIG. 1, the optical fiber cable according to the embodiment of the present invention includes a plurality of optical fibers 1 twisted together, a press-wound tape 3 covering the periphery of the plurality of optical fibers 1, and a plurality of A string-like body (also referred to as an “ultraviolet curable resin coated string”) 2 provided linearly along the longitudinal direction of the cable between the optical fiber 1 and the presser winding tape 3 and coated with an ultraviolet curable resin, and a presser. And a jacket 4 covering the periphery of the wound tape 3. Here, it is assumed that a plurality of optical fibers 1, the string-like body 2, and the presser winding tape 3 constitute one optical fiber unit 10.

  The plurality of optical fibers 1 are, for example, a collection of 24 optical fiber cores having a diameter of 0.25 mm. As the optical fiber 1, an optical fiber strand, an optical fiber core wire, an optical fiber tape core wire, etc. are employable. In the embodiment of the present invention, the number, type, size and the like of the optical fiber 1 are not particularly limited.

  2 and 3 show a plurality of optical fibers 1 and a string-like body 2 in a state of being wrapped in the press-wound tape 3 shown in FIG. The plurality of optical fibers 1 may be twisted in an SZ shape as shown in FIG. 2, or may be twisted in one direction as shown in FIG. Furthermore, although not shown, the plurality of optical fibers 1 may have a composite shape in which unidirectional twisting and SZ twisting are interchanged in the middle.

  The twist pitch of the plurality of optical fibers 1 is preferably 300 mm to 1000 mm, and the twist angle when the plurality of optical fibers 1 are twisted in an SZ shape as shown in FIG. 2 is preferably 180 ° to 360 °. When the twist pitch is less than 300 mm, if the wire speed is increased at the time of cable production, it is necessary to turn a number of dividing boards (aggregate twisting machine) for twisting, and the productivity decreases. On the other hand, when the twist pitch exceeds 1000 mm or the twist angle is smaller than 180 °, the plurality of optical fibers 1 are stretched substantially linearly, and transmission loss at low temperature increases when the optical fiber cable is bent. . On the other hand, if the twist angle is larger than 360 °, there is a problem in the take-out property of the optical fiber 1 when the optical fiber cable is branched at a predetermined pitch.

  The press-wound tape 3 shown in FIG. 1 can use a thermoplastic resin such as polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), or nylon (registered trademark).

  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.

  A pair of tear strings (lip cords) 5 a and 5 b are embedded in the jacket 4 at positions facing each other across the optical fiber unit 10. The pair of tear strings 5a and 5b is made of a twisted yarn made of polyester, a fiber string-like body such as an aramid fiber or glass fiber, or the like.

  Further, a pair of strength members (tension members) 6a and 6b are embedded in the jacket 4 at positions facing each other with the optical fiber unit 10 in between in a direction orthogonal to a straight line connecting the pair of tear strings 5a and 5b. ing. The pair of strength members 6a and 6b is made of a metal wire such as a steel wire or fiber reinforced plastic (FRP). The tensile bodies 6a and 6b are not limited to linear bodies, but may be strips. The band-like body is a long band-like one having a flat cross section, an elliptical shape, or a rectangular shape such as a rectangle.

  The position of the string-like body 2 is a straight line connecting the pair of strength members 6a and 6b in order to prevent the string-like body 2 from distorting the optical fiber 1 and increasing transmission loss when the optical fiber cable is bent. It is most preferable that the closer to a straight line connecting the pair of strength members 6a and 6b, the better.

  The string-like body 2 has a diameter of about 0.27 mm and may be larger than the diameter of the optical fiber 1. The cross-sectional shape of the string-like body 2 may be circular, elliptical, rectangular, or the like, and is not particularly limited. As shown in FIG. 4, the string-like body 2 includes a string portion 21 made of, for example, nylon and a coating layer 22 made of an ultraviolet curable resin coated on the surface of the string portion 21. The coating thickness T of the coating layer 22 is preferably about 0.1 mm to 0.5 mm. Making the coating thickness T of the coating layer 22 thinner than 0.1 mm is strict in manufacturing. On the other hand, when the coating thickness T of the coating layer 22 is thicker than 0.5 mm, the amount of the ultraviolet curable resin to be cured increases, and the productivity is lowered.

  Moreover, in order to suppress the movement of the optical fiber 1 in the cable longitudinal direction, it is preferable that the frictional resistance of the surface of the coating layer 22 of the string-like body 2 is larger than the frictional resistance of the coating layer of the surface of the optical fiber 1. The covering layer 22 of the string-like body 2 is in contact with the optical fiber 1 and the press-wound tape 3 without being bonded.

  According to the optical fiber cable according to the embodiment of the present invention, the plurality of optical fibers 1 and the string-like body 2 are obtained by applying the press-wound tape 3 with the string-like body 2 attached to the plurality of optical fibers 1. During this time, frictional resistance is generated between the string-like body 2 and the presser winding tape 3. As a result, the resistance between the plurality of optical fibers 1 and the press-wound tape 3 increases indirectly, making it difficult to move the core wire.

  Moreover, since many optical fibers contact with the string-like body 2 intermittently by twisting together the several optical fiber 1, a core wire movement is suppressed more.

  In addition, since the single string-like body 2 is placed along the press-wound tape 3, when a plurality of optical fiber units are accommodated in the outer jacket 4, the optical fiber unit is pressed without pressing the other optical fiber units. It is possible to reduce the diameter and density of the fiber cable.

(Optical fiber cable manufacturing equipment)
As shown in FIG. 5, the optical fiber cable manufacturing apparatus according to the embodiment of the present invention includes an optical fiber sending unit 101 that sends out a plurality of optical fibers 1 and a string-like body sending device that sends out a string-like body 2. 102, a press-wound tape delivery unit 103 that feeds the press-wound tape 3, a collective twisting machine 104 that gathers and twists a plurality of optical fibers 1, and a string-like body 2 attached to the periphery of the plurality of optical fibers 1 The guide (guide roller, guide pulley) 107 vertically attached with the presser winding tape 3 in the state, the tensile strength member sending portions 106a and 106b for sending the tensile strength members 6a and 6b, and the tear string sending portion 105a for sending the tear strings 5a and 5b, respectively. , 105b, and an extruder (extrusion head) 108 for extruding the resin used as the outer cover 4.

  Here, it is preferable to use the guide 107 having a smooth surface so that the coating layer 22 made of the ultraviolet curable resin coated on the surface of the string-like body 2 is not peeled off.

(Optical fiber cable manufacturing method)
Next, an example of an optical fiber cable manufacturing method according to the embodiment of the present invention using the optical fiber cable manufacturing apparatus shown in FIG. 5 will be described.

  (A) The optical fiber sending unit 101 shown in FIG. 5 sends out a plurality of optical fibers 1. The collective twisting machine 104 aggregates a plurality of optical fibers 1 and twists the plurality of optical fibers 1 in one direction or the SZ direction. The presser winding tape delivery unit 103 sends the presser winding tape 3. The guide 107 vertically attaches the press-wound tape 3 around the plurality of optical fibers 1 while attaching the string-like body 2 around the plurality of optical fibers 1.

  (B) The strength member sending units 106a and 106b send the strength members 6a and 6b. The tear string sending sections 105a and 105b send the tear strings 5a and 5b. Then, the bundle of optical fibers 1 to which the presser winding tape 3 is vertically attached is introduced into the extruder 108 together with the strength members 6a and 6b and the tear strings 5a and 5b.

  (C) The extruder 108 extrudes the resin to form the outer cover 4 around the presser winding tape 3. Thereafter, the optical fiber cable is completed by being cooled in a water tank or the like (not shown) and wound by a winder (not shown).

  According to the method for manufacturing an optical fiber cable according to the embodiment of the present invention, the optical fiber cable can be manufactured at a low cost with a simple line as compared with the case where a tape impregnated with an adhesive is used as described in Patent Document 3. Can be manufactured.

(Example)
The optical fiber cable which concerns on embodiment of this invention was produced as an Example. As the string-like body 2, a 900d nylon thread coated with an ultraviolet curable resin having an elastic modulus of 0.83 MPa to 1.30 MPa with a coating thickness of 0.1 mm to 0.5 mm is prepared. The cord-like body 2 is fed from the same direction as the presser winding tape 3 having a width of 20 mm and a thickness of 38 μm, and the periphery of the optical fiber 1 with the cord-like body 2 is wrapped with the presser winding tape 3 to cover the outer cover 4. did. An ultraviolet curable resin having a relatively high elastic modulus that does not compress other optical fibers 1 when mounting or bending the optical fiber 1 was selected. The twist pitch of the optical fiber 1 was set to 300 mm to 1000 mm, and the twist angle was set to 180 ° to 360 °. On the other hand, as a comparative example, an optical fiber cable having the same conditions as in the example was manufactured except that the string-like body 2 was not provided.

  With respect to the manufactured Examples and Comparative Examples, a batch pull-out test of the optical fiber unit was performed, the core wire pulling force was measured, a cable overhead wire vibration test at a low temperature was performed, and the protruding amount of the optical fiber was measured. . The measurement results are shown in FIG. From FIG. 6, it can be seen that the core wire pulling force in the example is higher than the comparative example with respect to the core wire pulling force in the collective pulling test. In addition, regarding the amount of protrusion of the optical fiber in the cable overhead line vibration test, it can be seen that the amount of protrusion of the optical fiber core decreased in the example, and the core wire movement was improved.

(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, although the case where the optical fiber unit 10 includes one string-like body 2 has been described in FIG. 1, a plurality of (two or more) string-like bodies are provided according to the mounting density of the optical fiber 1 or the like. May be. For example, as shown in FIG. 7, the optical fiber unit 10 may include a plurality (two) of string-like bodies 2a and 2b. The two string-like bodies 2a and 2b are preferably arranged at positions facing each other across a bundle of optical fibers on a straight line connecting the pair of strength members 6a and 6b. In addition, it is preferable to provide one string-like body from the viewpoint of complexity and cost when manufacturing the cable.

  Moreover, although the case where the optical fiber cable is provided with one optical fiber unit 10 is shown in FIG. 1, the optical fiber cable may be provided with a plurality of optical fiber units. Each optical fiber unit may have the same configuration as the optical fiber unit 10 shown in FIG.

  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.

DESCRIPTION OF SYMBOLS 1 ... Optical fiber 2, 2a, 2b ... String-like body 3 ... Pressing winding tape 4 ... Jacket | cover 5a, 5b ... Tear string 6a, 6b ... Strength body 10 ... Optical fiber unit 21 ... String part 22 ... Covering layer 101 ... Light Fiber sending unit 102 ... string-like body sending device 103 ... tape sending unit 104 ... collective twisting machine 105a, 105b ... string sending unit 106a, 106b ... strength body sending unit 107 ... guide 108 ... extruder

Claims (4)

A plurality of optical fibers twisted together;
A presser winding tape covering the periphery of the plurality of optical fibers;
A string-like body provided linearly along the longitudinal direction of the cable between the plurality of optical fibers and the presser winding tape, and coated with an ultraviolet curable resin,
A jacket covering the periphery of the presser winding tape,
It further comprises a pair of strength members embedded in the jacket,
The optical fiber cable, wherein the string-like body is arranged on a straight line connecting the pair of strength members. The optical fiber cable according to claim 1, wherein a coating thickness of the ultraviolet curable resin coated on the string-like body is 0.1 mm to 0.5 mm. The optical fiber cable according to claim 1 or 2 , wherein the elastic modulus of the ultraviolet curable resin coated on the string-like body is 0.83 MPa to 1.30 MPa. The optical fiber cable according to claim 1 or 2 , wherein the plurality of optical fibers are twisted in the SZ direction, a twist pitch is 300 mm to 1000 mm, and a twist angle is 180 ° to 360 °.

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