JP2006119459A - Optical fiber cable - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To acquire an allowable bending radius, to easily take out an optical fiber cord part and to improve the processability of the end of the optical fiber cord. <P>SOLUTION: The optical fiber is characterized in that a corrugate tube 21 having a slit 19 in the longitudinal direction is arranged on the outer periphery of the optical fiber cord 17 and the outer periphery of the corrugate tube 21 is covered by an outer skin 23 made of a thermoplastic resin. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an optical fiber cable used particularly for indoor wiring.

  Conventionally, as standardized in JIS C 6830, as shown in FIGS. 9 and 10, for example, on the outer periphery of the quartz optical fiber 103 having an outer diameter of 125 μmφ, UV resin having an outer diameter of 250 μmφ or from an outer diameter of 400 μmφ, for example. An optical fiber strand 107 is formed by coating a resin 105 such as a silicon resin, and an optical fiber core wire 111 is coated by coating a polyamide resin 109 having an outer diameter of 0.9 mmφ on the outer periphery of the optical fiber strand 107. Further, an optical fiber cord 117 is known as a structure in which, for example, a plurality of aramid fibers 113 are vertically attached to the outer periphery of the optical fiber core wire 111 and a PVC 115 having an outer diameter of, for example, 3 mmφ is covered as a jacket. It has been.

  In recent years, with the spread of fiber-to-the-home (FTTH), when an optical fiber cable penetrates into the home, the optical fiber cable is used in the home. Will be done frequently.

  Therefore, various optical fiber cables have been devised in order to prevent damage to the optical fiber cable due to slightly rough handling. Among them, optical fiber cables devised so as not to be bent smaller than a certain bending diameter have been proposed (Patent Documents 1 and 2).

These optical fiber cables have a structure in which a hard resin layer with a knot is formed on a part of the jacket of the optical fiber or the optical fiber cord, and the knot can be bent with a small force up to a certain bending radius R. This structure is possible and requires a large force to bend beyond the bending radius R.
Japanese Patent Laid-Open No. 11-223752 JP 2004-133005 A

  By the way, in the above-described conventional optical fiber cable, a hard resin layer having a knot is formed on a part of the jacket of the optical fiber or the optical fiber cord, so that the jacket of the optical fiber cord is removed. Have difficulty.

  In addition, it is important to secure a minimum bending radius against bending, which is a cause of breakage of the optical fiber, and to prevent ignition of the optical fiber due to fire in the home.

  Also, in order to secure the minimum bending radius, commercially available conduits and other corrugated tubes are often used. Usually, however, after installing such conduits and corrugated tubes on-site, optical fiber cords are used. Since it is pulled in, it is rarely integrated with the optical fiber cable.

  Further, in order to draw the optical fiber cord, the inner diameter of the electric wire tube or the corrugated tube must be larger than the outer diameter of the optical fiber cord to be drawn. However, after construction on site, the optical fiber cord moves in the longitudinal direction in the tube due to vibration or the like, and in the worst case, there is a risk of breaking the optical fiber. The use of a corrugated pipe made of metal is also one solution, but it requires a special production line (molded from tape and welded if necessary) instead of a fiber optic cable production line. To do.

  Furthermore, regarding flame retardancy, harmful gases are generated when the resin containing chlorine (halogen) is combusted. In recent years, in underpasses and indoors, it is necessary to select a non-halogen and flame-retardant resin that does not contain chlorine.

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

  In order to achieve the object to be solved by the above invention, an optical fiber cable of the present invention is provided with a corrugated tube having an inner diameter smaller than the outer diameter of the optical fiber cord having a slit in the longitudinal direction on the outer periphery of the optical fiber cord. It arrange | positions and coat | covers a jacket on the corrugated pipe outer periphery.

  In the optical fiber cable according to the present invention, it is preferable that a yarn is vertically attached between the corrugated tube and the optical fiber cord in the optical fiber cable.

  In the optical fiber cable according to the present invention, in the optical fiber cable, the corrugated tube is preferably made of a thermoplastic resin.

  In the optical fiber cable of the present invention, in the optical fiber cable, the thermoplastic resin is preferably polyamide or polypropylene.

  In the optical fiber cable of the present invention, in the optical fiber cable, it is preferable that one or more materials of the optical fiber cord, the corrugated tube, the yarn, and the jacket are a flame-retardant thermoplastic resin.

  As can be understood from the description of the means for solving the problems as described above, according to the present invention, the corrugation having an inner diameter smaller than the outer diameter of the optical fiber cord having a slit in the longitudinal direction on the outer periphery of the optical fiber cord. By arranging it on the tube and covering the outer periphery of this corrugated tube with the outer cover, it becomes possible to easily take out the optical fiber cord part while preventing the optical fiber from being broken by the bending of the optical fiber cable, The end workability of the optical fiber cord can be improved.

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

  1 and 2, an optical fiber cable 1 according to the present invention includes a quartz optical fiber 3 having an outer diameter of, for example, 125 μmφ at the center, and an outer periphery of the quartz optical fiber 3 having, for example, an outer diameter of 250 μmφ. An optical fiber 7 is formed by coating the UV resin 5. An optical fiber core 11 is formed by coating the outer periphery of the optical fiber 7 with a flame retardant polyolefin resin 9 having an oxygen index of 40 as a non-halogen flame retardant resin having an outer diameter of 0.9 mmφ, for example. Further, a flame retardant polyolefin resin 15 having an oxygen index of 40 is used as a non-halogen flame retardant resin having an outer diameter of 3.05 mmφ, for example, with a plurality of aramid fibers 13 vertically attached to the outer periphery of the optical fiber core 11 as a tensile body. An optical fiber cord 17 is formed by coating. On the outer periphery of the optical fiber cord 17, a corrugated pipe 21 having a slit 19 in the longitudinal direction and having an outer diameter of 5.1 mm, an inner diameter of 3.0 mm and made of polyamide resin or polypropylene fiber is disposed. 21 has a structure in which a flame retardant polyolefin resin 23 having an oxygen index of 40 as a non-halogen flame retardant resin having an outer diameter of 6.1 mmφ is coated on the outer periphery of 21. That is, the inner diameter D2 of the corrugated tube 21 is made smaller than the outer diameter D1 of the optical fiber cord 17 (D1> D2).

  With the above configuration, after removing the flame-retardant polyolefin resin 23 of the jacket, it becomes possible to easily take out the optical fiber cord 17 portion from the corrugated tube 21 having the slit 19, and at least save the labor of tearing vertically. it can. As a result, workability can be improved when, for example, connector processing is performed on the end of the optical fiber cord 17 or when connection work is performed at the end of the optical fiber cord 17, for example.

  By extruding the flame-retardant polyolefin resin 23 on the outer periphery of the corrugated tube 21, it becomes difficult to bend the corrugated tube 21 with the slit 19 below a certain bending diameter like the corrugated tube without the slit. It is possible to prevent the optical fiber from being broken by the bending of the optical fiber cable 1.

  By using any one or more materials of the optical fiber cord 17, the corrugated tube 21, the jacket 23, and the yarn 35 as a flame retardant resin, good flame retardant characteristics can be obtained. By making the inner diameter D2 of the corrugated tube 21 with the slit 19 smaller than the outer diameter D1 of the optical fiber cord 17 (D1> D2), the movement of the optical fiber cord 17 in the corrugated tube 21 can be prevented.

  For example, an SM type optical fiber 7 having an outer diameter of 250 μmφ is coated with a flame retardant polyolefin resin 9 having an oxygen index of 40 to form an optical fiber core 11 having an outer diameter of 0.9 mmφ. A plurality of aramid fibers 13 are vertically attached to the outer periphery of the optical fiber core wire 11, and a flame retardant polyolefin resin 15 having an oxygen index of 40 is extruded on the outer periphery to produce an optical fiber cord 17 having an outer diameter of 3.05 mmφ.

  The optical fiber cord 17 is housed in a corrugated tube 21 having a slit 19 having an inner diameter of 3.0 mm and an outer diameter of 5.1 mm, and a flame retardant polyolefin resin 23 having an oxygen index of 40 is extruded on the outer periphery thereof. A 1 mm optical fiber cable 1 was manufactured.

  When the bending test of the manufactured optical fiber cable 1 was performed, the optical fiber cable 1 was easily bent up to a bending radius R = 15 mm. However, to bend the optical fiber cable 1 so that the bending radius was smaller than 15 mm. It was confirmed that a great force was necessary.

  As the combustion test, it passed the combustion test of the standard of JIS C 3005.

  As shown in FIG. 3, the left end, which is one end of the optical fiber cable 1, holds the corrugated tube 21 with the clamp device 34, and the right end, which is the other end of the optical fiber cable 1, holds the optical fiber cord 17. However, as a result of pulling with 10N force, the optical fiber cord 17 did not move.

  Further, it was confirmed that the flame retardant polyolefin resin 23 which is the outer sheath of the optical fiber cable 1 was removed by about 30 cm and the optical fiber cord 17 could be easily taken out.

  FIG. 4 shows another optical fiber cable 1 instead of FIG. 4, parts that are the same as the parts in FIG. 2 are given the same reference numerals, and redundant descriptions are omitted.

  In FIG. 4, since the inner diameter D2 of the corrugated tube 21 is smaller than the outer diameter D1 of the optical fiber cord 17 (D1> D2), the optical fiber cord 17 cannot move in the tube, but in order to further enhance the effect of preventing the movement in the tube, the corrugated tube A yarn 35 serving as an intervening body is vertically provided between 21 and the optical fiber cord 17. As the yarn 35, for example, an aramid fiber, a polypropylene fiber, a polyethylene fiber, or the like is used. Further, in an optical fiber cable that requires flame retardancy, it is preferable to use a flame retardant yarn as the yarn.

  With the configuration described above, the effect of preventing the movement of the optical fiber cord 17 in the corrugated tube 21 can be enhanced by vertically attaching the yarn 35 as an intervening body between the corrugated tube 21 and the optical fiber cord 17. By making the yarn 35 vertically attached as an intervening body between the corrugated tube 21 and the optical fiber cord 17 into a flame retardant yarn, good flame retardant characteristics can be obtained.

  The manufacturing method of the above-described optical fiber cable 1 will be briefly described with reference to FIGS. 5, 6, and 7. In FIG. 5, the corrugated pipe 21 fed out from the corrugated pipe delivery bobbin 37 is a corrugated pipe opening device 39. It is introduced into the apparatus from one inlet 41. As shown in FIGS. 6 and 7, the corrugated tube 21 is gradually slit by the opening outer die 43 and the opening core 45 until the opening becomes wider than the outer diameter of the optical fiber cord 17. The part 19 is opened. The optical fiber cord 17 fed out from the optical fiber cord delivery bobbin 47 is introduced into the inside of the device through another inlet 49 of the corrugated tube opening device 39, and then the corrugated tube 21 is opened from the opening of the corrugated tube 21. It is inserted into the tube 21. afterwards. The corrugated tube 21 is preferably made of a material having a small plastic deformation degree so that the corrugated tube 21 is restored to the original tubular shape as much as possible.

  Thereafter, the optical fiber cord 17 inserted into the corrugated tube 21 is sent to the extruder 51 to become the optical fiber cable 1, and is wound around the optical fiber cable winding bobbin 57 through the cooling tank 53 and the take-up machine 55 to manufacture. Is done.

It is a perspective view of the optical fiber cable of this invention. It is a longitudinal cross-sectional view in FIG. It is explanatory drawing for performing the tension test of an optical fiber cable. It is a longitudinal cross-sectional view of the other optical fiber cable of this invention. It is a front view which shows the manufacturing method of the optical fiber cable of this invention. FIG. 6 is an enlarged cross-sectional view of the corrugated tube opening device taken along line VI-VI in FIG. 5. It is an expanded sectional view along the VII-VII line in FIG. It is a perspective view of the conventional optical fiber cable. It is sectional drawing in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical fiber cable 3 Quartz optical fiber 5 UV resin 7 Optical fiber strand 9 Non-halogen flame retardant resin 11 Optical fiber core wire 13 Aramid fiber 15 Non-halogen flame retardant resin 17 Optical fiber cord 19 Slit 21 Corrugated tube 23 Non-halogen flame retardant Resin 35 yarn

Claims (5)

  An optical fiber cable characterized in that a corrugated pipe having an inner diameter smaller than the outer diameter of the optical fiber cord having slits in the longitudinal direction is disposed on the outer circumference of the optical fiber cord, and the outer jacket is coated on the outer circumference of the corrugated pipe .   2. An optical fiber cable according to claim 1, wherein a yarn is vertically attached between the corrugated tube and the optical fiber cord.   3. The optical fiber cable according to claim 1, wherein the corrugated tube is made of a thermoplastic resin.   The optical fiber cable according to claim 3, wherein the thermoplastic resin is polyamide or polypropylene. The optical fiber cable according to claim 1 or 2, wherein one or more materials of the optical fiber cord, the corrugated pipe, the yarn, and the jacket are flame-retardant thermoplastic resin.

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