JP2005091616A - Optical fiber cable and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical fiber cable having strength against curvature, without deteriorating the tensile strength, by using the tension resistant body of a noninductive resin material. <P>SOLUTION: The optical fiber cable 1 has a long optical element part 9 provided with: a coated optical fiber 3; the tension resistant body 5 disposed at both ends of the coated optical fiber 3 along the longitudinal direction of the coated optical fiber 3, in which a plurality of noninductive resin substances are twisted together; and a cable sheath 7 for coating the coated optical fiber 3 and the tension resistant body 5, in which at least one notch part 11 is formed on the surface of the cable sheath 7 on each side of the coated optical fiber 3, with respect to the second direction perpendicular to the first direction connecting the tension resistant body 5, in a plane perpendicular to the longitudinal direction. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an optical fiber cable and a manufacturing method thereof.

  About 1 or 2 cores are usually used as optical fiber cables (drop cables) for premises and aerials. However, with the expansion of FTTH (Fiber to the home), it is about 4 to 10 cores for small-scale condominiums and buildings. Multi-center demand is expected.

  Further, from the viewpoint of the post-branch workability, it is considered effective to use a single strand (or a tape optical fiber core having about two cores) as the optical fiber core to be housed.

  When an attempt is made to design a multi-fiber optical fiber cable including a single optical fiber, a loose tube cable, a slot cable, and the like are conceivable. However, since the outer diameter is large and the cost is high, FIG. A cable that follows the simple drop-indoor cable 101 with a small diameter as shown in FIG. That is, in FIG. 6, a drop indoor cable 101 is a single optical fiber core wire 103 and an optical element tensile body 105 disposed on both sides in parallel in the vicinity thereof and covered with a cable sheath 107. A notch 109 is formed on the surface of the cable sheath 107 on both sides (up and down in FIG. 6) of the optical fiber core wire 103 in a direction perpendicular to the direction in which the optical element strength members 105 are connected. (For example, refer to Patent Document 1).

Referring to FIG. 7, the optical fiber drop cable 111 is a long cable in which the cable sheath 107 of the drop indoor cable 101 is covered with the support wire 113 with the same sheath material 115 as the cable sheath 107. The support wire portions 117 are integrated in parallel with each other via a neck portion 119 (see, for example, Patent Document 2).
JP 2000-171673 A JP 2001-83385 A

  By the way, in the conventional optical fiber drop cable 111 (or the drop indoor cable 101), a steel wire or glass FRP is used as the tensile element 105 for the optical element.

  When a steel wire is used as the optical element tension member 105, a termination box attached to the wall of the subscriber's house to avoid damage to the equipment in the subscriber's house and the risk of fire due to the influence of the induced lightning surge. Is connected to the home wiring cable. Further, glass FRP is suitably used as a non-inductive material tensile element 105 for an optical element in order to draw it directly into the house without connecting to the house cable.

  When a steel wire is used for the optical element strength member 105, a steel wire is obtained by applying a minimum bend to the optical element portion (corresponding to the drop / indoor cable 101) during the disconnecting operation from the cable support wire portion 117. As a result, the optical element portion 101 after being cut off may be curled, resulting in poor workability.

  In addition, when glass FRP is used for the optical element strength member 105, if the optical element portion 101 is subjected to a minimum bend during the disconnection from the cable support wire portion 117, the optical element strength member 105 is easily bent. May occur, causing an increase in optical transmission loss and disconnection of the optical fiber core 103. For this reason, it is necessary to carefully perform the installation work so that the optical element portion 101 is not subjected to a minimum bend, and when the optical element tensile member 105 is bent, the optical fiber drop cable 111 may be exchanged. Since it is necessary, there is a problem that the laying workability is poor.

  As the above countermeasure, for example, a method of using a non-inductive material made of, for example, high-strength plastic for the tensile element 105 for an optical element is conceivable. High-strength plastic materials are advantageous in that they are more flexible than steel wires and glass FRP, and are not easily buckled.

  However, there is a problem that the tensile elastic modulus is lower than that of the glass FRP, and the tensile strength of the optical element portion 101 is inferior. In order to obtain the tensile strength equivalent to that of the optical element portion 101 using the glass FRP for the optical element strength member 105, it is necessary to increase the cross-sectional area, but the optical element portion 101 is bent due to the increase in the cross-sectional area. As a result, there is a problem that the strain applied to the surface of the optical element strength member 105 becomes large, and it is easy to cause buckling and breakage.

  The present invention has been made to solve the above-described problems.

  An optical fiber cable according to the present invention includes an optical fiber core, a tensile body that is disposed on both sides of the optical fiber core along the longitudinal direction of the optical fiber core, and a plurality of non-inductive resin materials are twisted together. A cable sheath covering the optical fiber core and the tensile body on both sides of the optical fiber core in a second direction perpendicular to the first direction connecting the tensile body in a plane perpendicular to the extending direction. And a cable sheath having at least one notch formed on the surface of the cable sheath.

  The optical fiber cable according to the present invention is a long cable support line portion in which the support line is covered with a sheath in the optical fiber cable, and the cable support line portion is arranged in parallel with the optical element portion and integrated. It is preferable to have.

  In the optical fiber cable according to the present invention, it is preferable that the optical fiber core has one or a plurality of strands or tape cores.

  An optical fiber cable manufacturing method according to the present invention includes an optical fiber core and a plurality of non-inductive resin materials arranged on both sides of the optical fiber core along the longitudinal direction of the optical fiber core. A step of feeding each of the strength members to the extrusion head of the extruder, a step of extruding a thermoplastic resin to the extrusion head, and an optical element portion in which the optical fiber core wire and the strength member are covered with a cable sheath. Forming notches on the surface of the cable sheath on both sides of the optical fiber core in the second direction perpendicular to the first direction connecting the strength members in a plane perpendicular to the longitudinal direction. And a step of forming an optical element part including the step.

  In the method of manufacturing an optical fiber cable according to the present invention, an optical fiber core is disposed on both sides of the optical fiber core along the longitudinal direction of the optical fiber core, and a plurality of non-inductive resin materials are twisted together. A process of feeding a tensile body and a support wire to the extrusion head of the extruder, a process of extruding a thermoplastic resin to the extrusion head, and covering the optical fiber core and the tensile body with a cable sheath The optical element portion and the cable support wire portion in which the support wire is covered with a sheath are arranged in parallel and integrally formed, and in a plane perpendicular to the longitudinal direction of the optical fiber core wire Forming a step including forming notches on the surface of the cable sheath on both sides of the optical fiber core wire in the second direction perpendicular to the first direction connecting the strength members. It is an feature.

As will be understood from the means for solving the above problems, according to the present invention, since the tensile strength member is formed by twisting a plurality of small-diameter high-strength non-inductive resin materials, The optical fiber cable is strong against bending without impairing the tensile strength. In other words, the tensile body is made by twisting a plurality of non-inductive resin materials having a small diameter to reduce the strain applied to each tensile body when the optical fiber cable is bent, even if the cross-sectional area is large.・ The occurrence of damage can be suppressed. Moreover, the tensile strength can be ensured by increasing the cross-sectional area.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  Referring to FIG. 1, as an optical fiber cable 1 according to the first embodiment of the present invention, an optical fiber core wire 3 made of a single strand extending in a longitudinal direction perpendicular to the paper surface in FIG. It has been. In the vicinity of both sides of the optical fiber core 3 (left and right in FIG. 1), the optical element strength member 5 is arranged in parallel with the optical fiber core 3.

  The optical element strength member 5 is formed by twisting a plurality of thin high-strength non-inductive resin materials. In this embodiment, the non-inductive resin material has an outer diameter of, for example, 0.3 mm. 7 polyester strings are twisted together with a twist number of 50 times / m, for example, to an outer diameter of 0.9 mm.

  The optical fiber core wire 3 and the optical element strength member 5 are covered with a cable sheath 7 made of a thermoplastic resin to form a long optical element portion 9. In a plane orthogonal to the longitudinal direction of the fiber core wire 3, the optical fiber core wire 3 in a direction (vertical direction in FIG. 1; second direction) orthogonal to the arrangement direction (first direction) of the optical element strength members 5. A notch portion 11 is formed on the surface of the cable sheath 7 located on both sides (up and down in FIG. 1).

  In the case of the optical fiber cable 1 shown in FIG. 1, the notch portion 11 is provided so that the surface 13 connecting the notch portions 11 facing each other intersects the optical fiber core wire 3. Therefore, when the cable sheath 7 is torn from the notch 11 and the optical fiber core wire 3 is extracted, the extraction can be easily performed.

  In the above configuration, since the optical element strength member 5 is used which is formed by twisting a plurality of small-diameter high-strength non-inductive resin materials, the tensile strength of the optical fiber cable 1 is not impaired. The cable is strong against bending. That is, when the optical fiber cable 1 is bent, the strain applied to each non-inductive resin material is reduced, the occurrence of buckling / breakage of the optical element tensile member 5 is suppressed, and the cross-sectional area is increased. As a result, the tensile strength is secured.

  FIG. 2 shows an optical fiber cable 1 according to a second embodiment of the present invention. The optical fiber cable 1 has a long optical element portion 9 similar to that shown in FIG. The optical fiber cable 1 further includes a long cable support line portion 19 in which the support line 15 is covered with a sheath 17. The support wire 15 is made of, for example, a steel wire (metal wire). The sheath 17 is a thermoplastic resin and is formed integrally with the cable sheath 7. Therefore, the cable support line portion 19 is integrated with the optical element portion 9 in parallel via the neck portion 21. In the plane orthogonal to the longitudinal direction of the fiber core wire 3, the support wire 15, the pair of optical element strength members 5 and the fiber core wire 3 are arranged along the first direction.

  With this configuration, the optical fiber cable 1 is formed by integrating the long cable support line portion 19 in which the support wire 15 is covered with the sheath 17 and the optical element portion 9 through the neck portion 21 in parallel with each other. It can be used as an optical fiber drop cable and has the same effect as the effect in FIG.

  The optical fiber core 3 may be a plurality of strands or a tape strand in addition to a single strand. In particular, a 0.25 mm strand is most preferably used, but a 2-core tape core or a single core of about 0.4 to 0.9 mm is also used.

  Next, a method for manufacturing the optical fiber cable 1 shown in FIG. 2 will be described.

  FIG. 3 shows a cross-sectional view of the extrusion head 23, and a nipple portion 25 as shown in FIG. 4 is provided at the center of the extrusion head 23 of the extruder. As shown in FIG. 5, for example, a die portion 29 having a die hole 27 having substantially the same shape as the outer peripheral shape of the cross section of the optical fiber cable 1 of FIG. 2 is provided on the outer periphery of 25. In this case, protrusions 31a and 31b for forming the notch portion 11 are provided in the die hole 27 at a position corresponding to the notch portion 11 of the optical fiber cable 1 in FIG. Yes. A flow path 33 through which the thermoplastic resin P as a sheath is pushed out is provided between the die portion 29 and the nipple portion 25.

  Further, as shown in FIG. 4, for example, a nipple hole 35 as a through hole through which the optical fiber core wire 3 passes is formed in the nipple portion 25, and the nipple hole 35 has a substantially circular cross section. . Further, on both outer sides of the nipple hole 35, there are provided nipple holes 37 through which the optical element strength member 5 formed by twisting a plurality of small-diameter high-strength non-inductive resin materials are twisted. A nipple hole 39 through which the support line 15 passes is formed on the outside (left side) of the nipple hole 37.

  3 and 4, the optical fiber core wire 3 wound on a reel (not shown) provided on the right side in FIG. 3 and FIG. 4, and a plurality of high-strength non-inductive resin materials having a small diameter are previously twisted together. The two optical element strength members 5 and the support wires 15 are drawn out and sent into the extrusion head 23.

  Further, the optical fiber core wire 3 passes through the nipple hole 35 of the nipple portion 25 in the extrusion head 23, and the two optical element strength members 5 pass through the nipple holes 37 of the nipple portion 25, and further One support line 15 passes through the nipple hole 39 and travels to the left in FIGS. 3 and 4, and the molten thermoplastic resin P is pushed out from the flow path 33 of the die portion 29, thereby being shown in FIG. 2. Thus, the optical fiber cable 1 can be obtained.

  In short, the manufacturing method of the optical fiber cable 1 has the following characteristics. That is, in this manufacturing method, the extrusion head 23 is used, and this extrusion head 23 has the following.

(A) The tip portion has a truncated cone (or truncated cone) shape, and the tip surface (or truncated surface) 25a has a nipple hole 35 for allowing the fiber core wire 3 to pass therethrough and a pair of tensile elements for optical elements. Nipple portion 25 having a pair of nipple holes 37 for allowing 5 to pass through,
(B) A die portion 29 having a conical inner peripheral surface arranged parallel to the conical surface of the nipple portion 25 at a predetermined interval, and a sheath thermoplastic resin P together with the fiber core wire 3. A die portion 29 having protrusions 31a and 31b projecting into the die hole 27 in order to form the die hole 27 for extruding and the notch portion 11;
The nipple holes 37 are disposed on both sides of the nipple hole 35 in the first direction on the distal end surface 25a. Furthermore, the protrusions 31a and 31b are provided to face each other in a second direction orthogonal to the first direction in a plane parallel to the tip surface 25a.

  Further, in the first direction, it is desirable that the tip portions of the projecting portions 31 a and 31 b have substantially the same Cartesian coordinate value as the center of the nipple hole 35.

  And this manufacturing method has the following processes.

(1) Step of pulling out the optical fiber core wire 3 from the nipple hole 35 (2) Step of pulling out the optical element tensile body 5 from the nipple hole 37 (3) Thermoplastic resin together with the optical fiber core wire 3 from the die hole 27 (4) In front of the die hole 27 in the extrusion direction, the thermoplastic resin P surrounds the optical fiber core wire 3 and the optical element strength member 5 to cure the thermoplastic resin P. Step of integrating the optical fiber core wire 3 and the optical element tensile body 5 Here, a step of drawing the optical fiber core wire 3 from the nipple hole 35, and a step of drawing the optical element tensile body 5 from the nipple hole 37, The process of extruding the thermoplastic resin P or the like from the die hole 27 is performed simultaneously.

  Moreover, according to the said manufacturing method, the optical fiber cable 1 provided with the optical fiber core wire 3, the optical element strength member 5, the sheaths 7 and 17, and the support wire 15 can be rapidly manufactured in a series of continuous processes.

  With the above configuration, the molten thermoplastic resin P pushed out from the flow path 33 between the nipple portion 25 and the die portion 29 is solidified while passing through the die hole 27. Therefore, the optical fiber cable 1 shown in FIG. 2 can be obtained.

  In addition, the optical fiber cable 1 as shown in FIG. 1 can be obtained using another dice | dies part, without supplying said support wire 15. FIG. Further, according to the above manufacturing method, the optical fiber cable 1 including the optical fiber core wire 3, the optical element strength member 5, and the sheath 7 can be quickly formed in a series of continuous processes as in the manufacturing method shown in FIGS. Can be manufactured.

  Next, the performance of the optical fiber cable 1 according to the embodiment of the present invention will be described in detail.

  The optical fiber cable 1 of FIG. 2 was manufactured as a test cable. This test cable is a cable having an outer diameter of 2.0 mm × 5.5 mm, in which the optical element strength member 5 having an outer diameter of 0.9 mm is formed by twisting seven polyester strings having an outer diameter of 0.3 mm. .

  When the characteristic values such as transmission loss and loss temperature fluctuation of the above test cable were measured, the transmission loss at a measurement wavelength of 1.55 μm was 0.25 dB / km or less, and the loss temperature fluctuation was 0 to −30 ° C. to + 70 ° C. Good results of 1 dB / km or less were obtained.

  Moreover, about the optical element part 9 which cut | disconnected the cable support wire part 19, when the load from which elongation rate becomes 0.3% was measured, it was 78N.

  Similarly, for a conventional optical fiber cable (hereinafter referred to as “comparison cable”) in which a glass FRP having an outer diameter of 0.5 mm is used as a tensile body for an optical element, a load with an elongation of 0.3% is measured. As a result, it was 73N. Therefore, it was confirmed that the test cable of this embodiment described above has a tensile strength equal to or higher than that of the conventional comparative cable.

  In addition, by bending the test cable and the comparison cable, the bending radius when the optical element strength member 5 was bent was confirmed. The comparison cable was bent at a bending radius of about 9.5 mm. However, the test cable has a bending radius of 3.5 mm, and is confirmed to have excellent buckling resistance.

  From the above, the optical fiber cable 1 of this embodiment has a feature that it is more flexible than a conventional comparative cable using a tensile member for optical elements of glass FRP and is not easily buckled. Yes. That is, the optical fiber cable 1 can be bent even if the cross-sectional area is increased by using the optical element strength member 5 formed by twisting a plurality of non-inductive resin materials made of high-strength plastic. The strain applied to the surface of the optical element strength member 5 can be reduced. For this reason, the cross-sectional area can be increased.

  As a result, the optical fiber cable 1 of this embodiment has a tensile strength equivalent to that of a conventional optical fiber cable using glass FRP as a tensile member for optical elements, and the optical fiber cable 1 is bent when the optical fiber cable 1 is bent. It is possible to prevent bending and breakage. Further, since the occurrence of curling is eliminated in the optical element portion 9 after the cable support line portion 19 is cut off, the laying workability of the optical fiber cable 1 can be greatly improved.

  In addition, this invention is not limited to embodiment mentioned above, It can implement in another aspect by making an appropriate change.

It is sectional drawing of the optical fiber cable of 1st Embodiment of this invention. It is sectional drawing of the optical fiber cable of 2nd Embodiment of this invention. It is sectional drawing of an extrusion head part. It is a perspective view of a nipple part. It is a perspective view of a die part. It is sectional drawing of the conventional optical fiber cable. It is sectional drawing of the other conventional optical fiber cable.

Explanation of symbols

1 Optical fiber cable (in this embodiment)
DESCRIPTION OF SYMBOLS 3 Fiber core 5 Strength element for optical elements 7 Cable sheath 9 Optical element part 11 Notch part 15 Support line 17 Sheath 19 Cable support line part 21 Neck part 23 Extrusion head 25 Nipple part 29 Die part

Claims (5)

An optical fiber core,
A tensile body disposed on both sides of the optical fiber core along the longitudinal direction of the fiber core and twisted with a plurality of non-inductive resin materials,
A cable sheath for covering the optical fiber core and the tensile body, and cables on both sides of the optical fiber core in a second direction perpendicular to the first direction connecting the tensile bodies in a plane perpendicular to the longitudinal direction. Cable sheaths each having at least one notch formed on the surface of the sheath;
An optical fiber cable comprising a long optical element portion comprising:   2. An optical fiber according to claim 1, wherein the optical fiber has a long cable support line part in which a support line is covered with a sheath, the cable support line part being arranged in parallel with the optical element part and integrated therewith. cable.   The optical fiber cable according to claim 1, wherein the optical fiber core includes one or more strands or a tape core. Extruders that run an optical fiber core and a tensile body that is arranged on both sides of the optical fiber core along the longitudinal direction of the optical fiber core and is twisted with a plurality of non-inductive resin materials. Supplying to the extrusion head of
Extruding a thermoplastic resin into the extrusion head;
Forming an optical element portion in which the optical fiber core wire and the tensile body are covered with a cable sheath, wherein the optical element portion in the second direction orthogonal to the first direction connecting the tensile bodies in a plane perpendicular to the longitudinal direction. Forming an optical element portion including a step of forming a notch portion on the surface of the cable sheath on both sides of the optical fiber core; and
An optical fiber cable manufacturing method comprising: An optical fiber core, a tensile body disposed on both sides of the optical fiber core along the longitudinal direction of the optical fiber core, and a plurality of non-inductive resin materials twisted together, and a support wire, respectively, run And supplying to the extrusion head of the extruder,
Extruding a thermoplastic resin into the extrusion head;
An optical element portion in which the optical fiber core wire and the tensile body are covered with a cable sheath, and a cable support wire portion in which the support wire is covered with a sheath are arranged in parallel and integrally formed, Forming a notch on the surface of the cable sheath on both sides of the optical fiber core in a second direction perpendicular to the first direction connecting the strength members in a plane perpendicular to the longitudinal direction of the optical fiber core. Molding process;
An optical fiber cable manufacturing method comprising:

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