JP2004070042A - Optical cable and method for manufacturing optical cable - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical cable which holds heat resistance beyond a predetermined level, without using metal material. <P>SOLUTION: A cable core 2 containing a coated optical fiber is wound with a heat resistant and non-conductive member of glass tape 3a, etc. and covered with resin, such as polyethylene. Thus, a cable jacket (sheath) 4 is formed. The glass tape 3a, etc. can apply the heat resistance without impairing non-inductivity of the optical cable, because the glass tape 3a, etc. are incombustible and nonconductive. Accordingly, the reservation of the non-inductivity and high heat resistance by using the nonmetal optical cable are made compatible. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an optical cable having non-inductive properties without using a metal material and having high heat resistance, and a method for manufacturing the same.
[0002]
[Prior art]
As for optical cables, cables of various specifications are provided according to applications and required performance. For example, in order to obtain a predetermined level of heat resistance in an optical cable, a metal material is used as a sheath of an optical fiber, or a material obtained by combining a resin and a metal is used. As a composite of a resin and a metal, a LAP sheath type composite of a polyethylene resin layer and an aluminum tape has been provided. In addition to heat resistance, it is common to use a thin metal or metal tube for the sheath or use a steel material for the tension member in order to provide mechanical properties against tensile strength and bending stress, moisture resistance and waterproofness. is there.
[0003]
FIG. 6 is a schematic cross-sectional view showing an example of a layered cable in a general-purpose optical cable. In the figure, 10 is an optical cable, 11 is a tension member, 12 is an optical fiber core, 13 is a buffer layer, 14 is a presser winding, and 15 is A sheath, 15a is a metal tape constituting the sheath, and 15b is a resin layer constituting the sheath. In a layered cable having a metallic structure, a LAP sheath formed by bonding a metal tape 15a of aluminum or the like to the inner surface of a resin layer 15b of, for example, polyethylene is used as the sheath 15, and a tension is used. A steel wire is used for the member 11. In the case of the non-metallic type, a polyethylene material is used for the sheath, and the tension member 11 is made of FRP.
[0004]
FIG. 7 is a schematic cross-sectional view showing an example of a 6-core type cord-type cable in a general-purpose optical cable. In the figure, reference numeral 20 denotes an optical cable, 21 denotes a tension member, 22 denotes an optical fiber cord, 23 denotes a holding coil, 24 denotes a sheath, 24a is a metal tape constituting the sheath, and 24b is a resin layer constituting the sheath. Similarly, in the case of the cord type cable, in the case of the metallic type, an LAP sheath made of a composite material of a resin layer 24b such as polyethylene and a metal tape 24a is used as the sheath 24, and a steel wire is used as the tension member 21. In the case of the non-metallic type, a polyethylene material is used for the sheath 24, and the tension member 21 is made of FRP.
[0005]
The LAP sheath is formed by wrapping a metal tape such as an aluminum tape or the like on which an adhesive resin is preliminarily laminated, around a tension member, a fiber core or a cable core made of a fiber cord, a cushioning material, etc. In general, the resin is continuously melt-coated by using an extruder so that the two are bonded and integrated.
[0006]
Regarding the heat resistance of an optical cable, a test method for evaluating the heat resistance of an optical cable is provided by Japanese Cable Manufacturers Association (JCMA) certification test No. 1040 concerning heat resistance. In the qualification test, stress is applied to the sample cable by a predetermined weight, the sample cable is burned under predetermined overheating and combustion conditions, and the disconnection state of the sample fiber and the increase state of the transmission loss are confirmed.
[0007]
When a metal sheath or a sheath made of a composite of metal and resin is used, even if the main components of the sample cable are melted and burned out by burning, the metal body remains, supporting the stress of the loaded weight. be able to.
[0008]
[Problems to be solved by the invention]
Although an optical fiber is inherently non-inductive, if a metal is used for a tension member or a sheath of a cable, for example, a spark may be applied to the metal part when a lightning strike occurs, and the cable may be broken. In addition, when an optical cable is provided along with a power cable, the metal material of the optical cable may receive a strong electric field from the power cable and affect its communication characteristics. That is, in order to maintain the non-inductive characteristics of the optical fiber with high reliability, it is preferable that the optical cable be formed of a non-metallic material.
[0009]
The present invention has been made in view of the above-described circumstances, and provides an optical cable capable of maintaining a predetermined level or more of heat resistance without using a metal material in a heat-resistant optical cable, and a method for manufacturing the same. It is the purpose.
[0010]
[Means for Solving the Problems]
An optical cable according to the present invention is an optical cable in which a sheath is coated around a cable core including an optical fiber core, and is composed of only a non-metallic material. A non-metallic material, and a sheath formed around the non-metallic material.
[0011]
The method for manufacturing an optical cable according to the present invention is a method for manufacturing an optical cable including only a non-metallic material.The outer periphery of a cable core is coated with a non-conductive and non-flammable non-metallic material, and the non-metallic material is coated. It is characterized in that a sheath is formed around it.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
The optical cable of the present invention is a non-metallic structure that does not use a metal, and has a characteristic of obtaining a heat resistance of a predetermined level or more.Instead of a metal tape in a conventional LAP sheath, a non-flammable fiber using a glass fiber is used. Construct the cable using the material. The tension member uses a non-metallic material such as FRP as in the conventional configuration. According to the configuration of the present invention, it is possible to provide an optical cable having high non-inductive property and high heat resistance without using a metal material.
[0013]
FIG. 1 is a view for explaining an embodiment of an optical cable according to the present invention. In the figure, reference numeral 1a denotes an optical cable, 2 denotes a cable core, 3a denotes a glass tape, and 4 denotes a cable sheath. In the present embodiment, a glass tape 3 a is wound around the cable core 2 and further covered with a resin such as polyethylene to form a cable jacket 4.
[0014]
The glass tape 3a is formed by weaving glass fibers into a tape shape, and the glass tape 3a is spirally wound around the cable core 2. Then, the member around which the glass tape 3a is wound is melt-coated with a resin such as polyethylene using an extruder and a coating die.
[0015]
The above-mentioned cable core 2 is provided with a tension member and a fiber core or a fiber cord, and may include a cushioning material or a conventional hold-down winding. Of course, the cushioning material is not essential depending on the cable configuration, and the glass tape 3a can be wound around the cable core 2 without using a conventional holding coil.
[0016]
Further, the configuration of the present invention can be applied not only to the configuration of the layer type cable or the cord type cable as described in the related art, but also to various types of cables such as a spacer type, a unit type, and a tape slot type. The same applies to the embodiments shown in FIGS.
[0017]
Since the glass fiber is a non-flammable material and a non-conductor, heat resistance can be imparted without impairing the non-inductive property of the optical cable. For example, in the above-described qualification test relating to heat resistance, the glass tape does not melt or burn and keeps its substantially initial shape, so that it can withstand the stress caused by the applied weight. Further, according to the present invention, both non-metallicity of the optical cable and non-metallicity can be secured and high heat resistance can be achieved. In addition, by adopting a configuration in which a glass tape is disposed on a conventional small-diameter optical cable core, an optical cable can be manufactured without greatly increasing the outer diameter.
[0018]
FIG. 2 is a view for explaining another embodiment of the optical cable according to the present invention. In the figure, 1b is an optical cable, 2 is a cable core, 3b is a glass sheet, and 4 is a cable jacket. The glass sheet 3b of the present embodiment is formed by weaving glass fibers into a wide sheet shape, and the glass sheet 3b is wound around the upper surface of the cable core 2, and the outer periphery of the glass sheet 3b is formed with a resin coating to form a cable sheath 4a. Do.
[0019]
FIG. 3 is a view for explaining still another embodiment of the optical cable according to the present invention. In the figure, 1c is an optical cable, 2 is a cable core, 3c is a glass cord, and 4 is a cable jacket. In the present embodiment, the glass string 3c is arranged around the cable core 2 using the glass string 3c in which the glass fiber is formed in a string shape, so that the longitudinal direction of the glass string 3c and the cable core 2 match. Then, a cable jacket 4 made of resin coating is formed on the outer periphery.
[0020]
FIG. 4 is a view for explaining still another embodiment of the optical cable according to the present invention. In the figure, 1d is an optical cable, 2 is a cable core, 3b is a glass sheet, 3c is a glass string, 4 is a cable jacket. It is. In the present embodiment, the glass string 3c shown in FIG. 3 and the glass sheet 3b shown in FIG. That is, the glass cord 3c is arranged around the cable core 2 so that the longitudinal direction of the glass cord 3c and the cable core 2 coincide with each other, and the glass sheet 3b obtained by weaving the glass fiber into a wide sheet is wound around the outer periphery of the glass cord 3c. Then, the outer periphery of the glass sheet 3b is covered with a resin to form the cable jacket 4. In the configuration shown in FIG. 4, the glass tape 3a shown in FIG. 1 may be used instead of the glass sheet 3b.
[0021]
FIG. 5 is a schematic sectional view of a cable for explaining still another embodiment of the optical cable according to the present invention, and shows a schematic sectional configuration of a unit type optical fiber. In FIG. 5, 1e is an optical cable, 3 is a hold-down winding made of a glass material, 4 is a jacket made of resin, 5 is a tension member, 6 is an optical fiber unit, 6a is a slot, 6b is an 8-core tape core, and 7 is a glass cord. It is.
[0022]
In the present embodiment, in a configuration in which the cable core is wound by holding down a glass tape or the like, by disposing the glass string 7 as an intervening object, deformation of the optical cable can be prevented, and stress applied to the optical fiber itself can be reduced. .
[0023]
The optical cable shown in FIG. 5 is a slot type optical cable in which five optical fiber units 6 are bundled and arranged around the tension member 5. Each optical fiber unit 6 has an 80-fiber configuration by laminating eight layers of eight-core tape 6b in each groove of a slot having eight grooves, and the entire optical cable constitutes a 3200-core cable. You.
[0024]
Also in the present embodiment, heat resistance and non-induction are realized by using the presser winding 3 made of a glass material, as in the above embodiments. As a specific configuration of the presser winding 3, a glass tape, a glass sheet, a glass string, or a combination thereof as described with reference to FIGS. 1 to 4 can be applied.
[0025]
Further, in the present embodiment, the glass cord 7 is interposed on the outer peripheral side of the portion where the optical fiber units 6 are adjacent to each other, and the holding roll 3 winds the optical fiber unit 6 and the tension member 5 together with the glass cord 7. . The glass string 7 is formed by forming glass fibers in a string shape, and is made by bundling a large number of glass fibers.
[0026]
The unit type optical cable of 3200 cores as shown in FIG. 5 has an outer diameter of, for example, about 50 mm, and there is a possibility that the cable may be deformed by an external stress due to a gap around the optical fiber unit 6. As in the embodiment, a highly reliable heat-resistant cable can be provided by winding with the presser winding 3 with the glass string 7 made of a heat-resistant and non-metallic material interposed therebetween.
[0027]
【The invention's effect】
As is apparent from the above description, according to the present invention, the cable is formed by using a non-combustible material using glass fiber or the like instead of the metal tape in the conventional LAP sheath, so that the metal-free non-metallic structure is used. Accordingly, it is possible to provide an optical cable and a method for manufacturing the same that maintain heat resistance of a predetermined level or more.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating an embodiment of an optical cable according to the present invention.
FIG. 2 is a diagram for explaining another embodiment of the optical cable according to the present invention.
FIG. 3 is a diagram for explaining still another embodiment of the optical cable according to the present invention.
FIG. 4 is a view for explaining still another embodiment of the optical cable according to the present invention.
FIG. 5 is a schematic sectional view of a cable for explaining still another embodiment of the optical cable according to the present invention.
FIG. 6 is a schematic sectional view showing an example of a layered cable in a general-purpose optical cable.
FIG. 7 is a schematic sectional view showing an example of a 6-core type cord-type cable in a general-purpose optical cable.
[Explanation of symbols]
1a, 1b, 1c, 1d, 1e, 10, 20 ... optical cable, 2 ... cable core, 3, 14, 23 ... holding down, 3a ... glass tape, 3b ... glass sheet, 3c ... glass string, 4 ... cable jacket (Sheath), 5, 11, 21 ... tension member, 6 ... optical fiber unit, 6a ... slot, 6b ... 8 core ribbon, 7 ... glass cord, 12 ... optical fiber, 13 ... buffer layer, 15, 24 ... sheath, 15a, 24a ... metal tape, 15b, 24b ... resin layer, 22 ... optical fiber cord.

Claims (8)

An optical cable in which a sheath is coated around a cable core including an optical fiber core, and is constituted only by a nonmetallic material, wherein a nonconductive and nonflammable nonmetallic material is provided around the cable core. Wherein the sheath is formed around the non-metallic material. The optical cable according to claim 1, wherein the non-metallic material is formed in a tape shape or a sheet shape, and the tape-shaped or sheet-shaped non-metallic material is wound around the cable core. The non-metallic material is formed in a string shape, and is disposed such that a longitudinal axis direction of the cable core and a longitudinal axis direction of the cord-shaped non-metallic material match. 2. The optical cable according to 1. The optical cable according to claim 1, wherein the non-metallic material is a glass material. At least a portion between the cable core and the non-metallic material is configured by interposing a reinforcing material having the same material as the non-metallic material or a property equivalent to the non-metallic material. The optical cable according to any one of claims 1 to 4. The said reinforcing material is formed in the shape of a string, and is arrange | positioned so that the longitudinal direction of the said cable core and the longitudinal direction of the said non-metallic material of a string may correspond. 6. The optical cable according to 5. The optical cable according to claim 5, wherein the reinforcing material is a glass material. A method of manufacturing an optical cable comprising a sheath coated around a cable core including an optical fiber core wire and comprising only a non-metallic material, wherein a non-conductive and non-flammable non-metallic A method for manufacturing an optical cable, comprising coating a material and forming a sheath around the non-metallic material.

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