JP2005208430A - Optical cable - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical cable excellent in handleability without causing uneven wear at the time of being laid, and reduced in diameter, weight, and cost, which copes with high laying tension and is useful as an optical cable for use in indoor wiring of a building and a general residence. <P>SOLUTION: The optical cable having cross section of circular shape has a sheath 13 formed at the outer circumference of coated optical fibers 11 through a tension fiber layer 12, wherein a tension body 14 consisting of tension fibers is embedded in the sheath 13. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an optical cable used for indoor wiring in buildings and general houses.

  As an optical cable for indoor wiring in a building or a general house, for example, one having a structure as shown in FIGS. 10 to 12 is known.

  The optical cable shown in FIG. 10 has a single-core optical fiber core 1 and two tensile wires 2 made of steel, FRP (fiber reinforced plastic), etc. arranged on both sides of the optical fiber core 1 and these are collectively made of a resin such as polyethylene. The outer cover 3 is formed by coating, and notches 3a and 3a for tearing are provided at the center of both long pieces of the outer cover 3 and at the portion where the single-core optical fiber core wire 1 is located. . The optical cable shown in FIG. 11 is a so-called slot-type optical cable. The single-core optical fiber core 1 is accommodated in a plurality of grooves (slots) 5 provided on the outer periphery of the slot rod 4 and pressed on the outer periphery. The outer cover 3 made of a resin such as polyethylene is provided via the wound layer 6. A tensile body 7 made of FRP or the like is embedded in the center of the slot rod 4. Furthermore, the optical cable shown in FIG. 12 has a tensile strength fiber 8 arranged around a single-core optical fiber core 1 and a jacket 3 made of a resin such as polyethylene coated thereon. In addition, although not shown in the drawings, various types of structures have been developed such as a structure in which a tensile body whose outer periphery is coated with a resin is connected to both sides of the optical cable shown in FIG. Reference 1).

  However, such conventional optical cables have the following problems.

  That is, first, since the cross-sectional shape of the optical cable shown in FIG. 10 is rectangular or elliptical, directionality occurs in the bending direction (bending only in the short axis direction of the cable as shown by the arrow in FIG. 10). In addition, it is difficult to handle, and when laying, only a part of the cable is rubbed against the piping and the like, and uneven wear tends to occur. In addition, there was a problem that it was difficult to increase the number of cores due to the structure (about 12 cores is the limit).

  On the other hand, in the optical cable shown in FIG. 11, there is no directionality in the bending direction and multi-core is easy. However, since the outer diameter becomes large, the repulsive force (rigidity) when bent is large, and there is a problem in terms of difficulty in handling as in the optical cable of FIG. Moreover, since there are many component members, there also existed a problem that weight became heavy and the price also became high.

In addition, the optical cable shown in FIG. 12 has a problem that when the cable jacket 3 is pulled with a strong force when laying, the jacket 3 extends. Furthermore, the optical cable shown in FIG. 12 has problems in handling and the like even in the case where the tensile strength members are connected to both sides.
JP 2001-249259 A

  As described above, optical cables for indoor wiring laid in buildings and general houses have been developed and put to practical use. However, each has its advantages and disadvantages and still has satisfactory characteristics. Is not obtained.

  The present invention has been made to solve such problems of the prior art, has excellent handleability, does not cause uneven wear during laying, and can be reduced in diameter, weight, and cost. An object of the present invention is to provide an optical cable useful for indoor wiring of buildings and ordinary houses, which can sufficiently cope with high installation tension.

  In order to achieve the above object, an optical cable according to a first aspect of the present invention is an optical cable having a circular cross section provided with a jacket on the outer periphery of an optical fiber core via a tensile strength fiber layer. Further, a tensile strength body made of a tensile strength fiber is embedded.

  According to a second aspect of the present invention, in the optical cable according to the first aspect, a plurality of strength members made of the strength fibers are equally arranged in the circumferential direction and embedded.

  According to a third aspect of the present invention, in the optical cable of the first or second aspect, the tensile fiber layer and the tensile body each have a tensile elastic modulus (initial tensile resistance shown in JIS L 1013) of 4.9 N / d ( Denier) or higher tensile strength fibers.

  According to a fourth aspect of the present invention, in the optical cable according to any one of the first to third aspects, the outer jacket has an outer diameter of 3 mm to 6 mm and an inner diameter of 1 mm to 4 mm. Tensile fibers (denier) to 10000d (denier) are embedded.

  According to the optical cable of the present invention, directionality does not occur when bending, and the cable can be reduced in diameter and rigidity can be reduced, so that handling properties are greatly improved, and uneven wear occurs during laying. Can also be suppressed. Further, since the number of constituent members can be reduced, not only the diameter can be reduced, but also the weight and cost can be reduced. Furthermore, since tensile strength fibers are embedded inside the jacket, the jacket does not stretch even if it is gripped and pulled with a strong force, and it can sufficiently cope with high laying tension. It becomes possible.

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

FIG. 1 is a cross-sectional view showing an embodiment of the optical cable of the present invention.
As shown in FIG. 1, an optical cable 101 according to this embodiment includes two single-core optical fibers 11, a tensile fiber layer 12 provided around the optical fiber core 11, and a resin having a circular cross section on the outer side. And an outer cover 13 formed by covering the cover. Two tensile strength members 14 made of tensile strength fibers are embedded in the outer sheath 13 at positions almost opposite to each other with the single-core optical fiber core wire 11 interposed therebetween.

  The single-core optical fiber core 11 is not particularly limited, and the outer periphery of the optical fiber is coated with a silicone resin or an ultraviolet curable resin, and the outer periphery is further coated with a nylon resin (usually nylon) And so on).

  Further, as the tensile strength fiber constituting the tensile strength fiber layer 12 provided around the single-core optical fiber core wire 11 and the tensile strength body 14 embedded in the jacket 13, poly-p-phenylene terephthalamide fiber or the like is used. Aramid fibers, polyarylate fibers, polyparaphenylene benzbisoxazole fibers, polyester fibers such as polyethylene terephthalate fibers, nylon fibers, and the like are used. The tensile strength fiber layer 12 is formed by vertically attaching such tensile strength fibers around each single-core optical fiber core wire 11. The tensile strength fiber constituting the tensile strength fiber layer 12 and the tensile strength fiber constituting the strength member 14 may be the same or different materials.

  Furthermore, examples of the resin constituting the outer cover 13 include polyurethane, polyethylene, polyvinyl chloride, and the like. Among these, polyurethane is preferable from the viewpoint of wear resistance and flexibility. In particular, when laying in a pipe, the use of polyurethane is preferred because of high demands for wear resistance and flexibility. In addition, a coloring agent and a flame retardant may be mix | blended with these resin.

  In the optical fiber cable 101 configured as described above, since the cable section has a circular shape, directionality is unlikely to occur when bending, and a material that can be reduced in diameter and has high rigidity is used. (The tensile strain applied in the longitudinal direction of the cable is mainly suppressed by the tensile fiber layer 12 and the tensile member 14 provided around the single-core optical fiber core 11). As a result, the wiring work can be carried out easily and smoothly. In addition, since it is difficult for directionality to occur when bending, it is possible to prevent the occurrence of uneven wear due to only a part of the cable coming into contact with piping or a wall during laying. Furthermore, since the number of constituent members can be reduced, not only the diameter can be reduced, but also weight reduction and cost reduction can be achieved. Furthermore, since the tensile strength fibers are embedded in the outer sheath 13, the outer sheath does not stretch even if the outer sheath is gripped and pulled with a strong force, and it can sufficiently cope with a high laying tension. be able to.

  In the present invention, if the thickness of the jacket 13 is too thin, the protective effect on the single-core optical fiber core wire 11 and the mechanical strength of the cable are insufficient, and conversely, if the thickness is too thick, the outer diameter and weight are too small. Increasing the diameter and reducing the weight become difficult. From this point of view, the thickness of the jacket 13 depends on the type of material constituting it, the number and types of the optical fiber cores 11 to be accommodated, etc., but generally the outer diameter is 3 mm to 6 mm, the inner diameter Is preferably in the range of about 1 mm to 4 mm.

  Further, the tensile body 14 formed of the tensile strength fibers 12 and the tensile strength fibers embedded in the outer sheath 13 also has a protective effect on the single-core optical fiber core wire 11 and pulls the outer sheath 13 if the amount of the tensile strength fibers is too small. The effect of preventing elongation at the time of pulling is reduced, and conversely, if it is too large, the thickness of the jacket 13 must be increased, the cable outer diameter becomes larger, and the cable in the piping etc. Causes an increase in the occupied area and a decrease in flexibility. From such a viewpoint, the total thickness of the tensile strength fibers constituting the tensile strength body 14 and the tensile strength fibers constituting the tensile strength fiber layer 12 is in the range of 7000d (denier) to 60000d (denier), and the tensile strength is increased. As the body 14, tensile strength fibers having a thickness of 1000d (denier) to 10000d (denier) are embedded (when each tensile strength body 14 is configured by concentrating a plurality of small-diameter tensile strength fibers, The total thickness is preferably in the range of 1000 d (denier) to 10000 d (denier).

  Moreover, it is preferable to embed each strength member 14 so that the distance from the outer peripheral surface of the jacket 13 is about 0.3 mm or more. If it is buried more outward than this, the tension member 14 may be damaged when the jacket 13 is damaged or worn during laying.

  Further, the tensile strength fiber layer and the tensile strength body 14 are preferably composed of tensile strength fibers each having a tensile modulus (initial tensile resistance shown in JIS L 1013) of 4.9 N / d (denier) or more. If (the initial tensile resistance shown in JIS L 1013) is too small, a large amount of tensile strength fibers must be used, and the cable outer diameter increases.

  In the present invention, for example, as shown in FIGS. 2 and 3, the number of single-core optical fibers 16 may be one, or may be three or more. The optical cable 102 shown in FIG. 2 is one in which two single-core optical fiber cores 11 are arranged in the above embodiment, and the optical cable 103 shown in FIG. 3 is a single-core optical fiber core wire in the above-described embodiment. Three 11 are arranged.

  Further, for example, as shown in FIGS. 4 to 6, one or more optical fiber tape cores 111 and 112 may be used instead of the single optical fiber core 11. The optical cable 104 shown in FIG. 4 is a two-core optical fiber in which two optical fiber strands are arranged in parallel instead of the two single-core optical fibers 11 and the outer periphery is collectively coated in the above embodiment. One tape core 111 is arranged, and the optical cable 105 shown in FIG. 5 is one in which two similar two-core optical fiber ribbons 111 are arranged. Furthermore, the optical cable 106 shown in FIG. 6 is a four-core cable in which four optical fiber strands are arranged in parallel instead of the two single-core optical fiber wires 11 and the outer periphery thereof is collectively covered in the above embodiment. Three optical fiber ribbons 112 are arranged.

  In the present invention, the number of strength members 14 made of strength fibers embedded in the jacket 13 is not particularly limited, and may be one, three or more. The optical cable 107 shown in FIG. 7 has three tensile members 14 arranged in the above embodiment, and the optical cable 108 shown in FIG. 8 has four tensile members 14 arranged in the above embodiment. . However, from the viewpoint of suppressing the elongation of the outer cover 13 and ensuring the strength of the outer cover 13, about two to five are preferable. In the case of arranging three or more, it is preferable to arrange them at substantially equal intervals in the circumferential direction as in the case of the above embodiment, and the embedding depth is about 0.3 mm from the outer peripheral surface of the jacket 13. It is preferable to embed so that it may become the above.

  Furthermore, in the present invention, for example, as shown in FIG. 9, a tear notch 15 may be provided on the outer peripheral surface of the jacket 21. During the cable connection work, the inner optical fiber core wire 11 can be easily taken out by tearing the jacket 13 starting from the tearing notches 15.

  Next, examples of the present invention will be described, but the present invention is not limited to the following examples.

Example An optical fiber having the structure shown in FIG. 1 was produced. First, 6 poly-p-phenylene terephthalamide fibers (Kevlar 49: Trademark) with a thickness of 1420d (denier) are vertically attached to the outer periphery of two single-core UV-curable resin-coated optical fibers having an outer diameter of 250 μm. However, an optical cable having an outer diameter of about 3 mm was manufactured by extruding the outer periphery of the flame retardant polyurethane into a pipe having a thickness of about 0.8 mm. When extruding flame retardant polyurethane, two of the vertically attached poly-p-phenylene terephthalamide fibers are embedded in the extrusion coating at a depth of about 0.4 mm from the outer peripheral surface. It was to so.

  The obtained optical cable was subjected to a heat cycle test (-10 ° C to + 60 ° C, 3 cycles), and the maximum transmission loss increase was examined. It was less than 0.05 dB / km and had good temperature characteristics. . Moreover, when wiring was actually attempted in the piping in the building, the cable could be freely bent in any direction, and the wiring could be performed smoothly, and at that time, the jacket did not extend.

Sectional drawing which shows one Embodiment of the optical cable of this invention. Sectional drawing which shows other embodiment of the optical cable of this invention. Sectional drawing which shows other embodiment of the optical cable of this invention. Sectional drawing which shows other embodiment of the optical cable of this invention. Sectional drawing which shows other embodiment of the optical cable of this invention. Sectional drawing which shows other embodiment of the optical cable of this invention. Sectional drawing which shows other embodiment of the optical cable of this invention. Sectional drawing which shows other embodiment of the optical cable of this invention. Sectional drawing which shows other embodiment of the optical cable of this invention. Sectional drawing which shows an example of the conventional optical cable. Sectional drawing which shows the other example of the conventional optical cable. Sectional drawing which shows the other example of the conventional optical cable.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Single fiber optical fiber, 12 ... Tensile fiber layer, 13 ... Outer sheath, 14 ... Tensile body which consists of tensile fiber, 101-109 ... Optical cable, 111, 112 ... Optical fiber tape core

Claims (4)

  An optical cable having a circular cross-section with a jacket on the outer periphery of an optical fiber core through a tensile fiber layer, wherein a tensile body made of a tensile fiber is embedded in the jacket.   The optical cable according to claim 1, wherein a plurality of strength members made of the strength fibers are equally arranged in the circumferential direction and embedded.   2. The tensile strength fiber layer and the strength member are each composed of a tensile strength fiber having a tensile modulus (initial tensile resistance shown in JIS L 1013) of 4.9 N / d (denier) or more. Or the optical cable of 2.   The outer jacket has an outer diameter of 3 mm to 6 mm and an inner diameter of 1 mm to 4 mm, and a tensile strength fiber having a thickness of 1000 d (denier) to 10000 d (denier) is embedded as the tensile strength body. 4. The optical cable according to any one of items 1 to 3.

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