JP2007183477A - Optical fiber cable - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical fiber cable which facilitates insertion to a pipe line, etc. without having to use using a lubricant and contributes the improvement of operation efficiency of laying operation. <P>SOLUTION: The optical fiber cable 70 is made by collectively covering at least an optical fiber 10 and a tension member 20 with a sheath 50, the coefficient of dynamic friction of an outer surface of the sheath 50 is 0.09 to 0.12. The optical fiber cable 70 comprises the sheath 50 made of high-pressure polymerization polyethylene resin, which contains a fatty acid amide type lubricant at a ratio of 0.18 wt.% to 0.32 wt.%. The optical fiber cable 70 comprises the fatty acid amide lubricant which is at least one kind selected from between erucic acid amide or oleic acid amide. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an optical fiber cable.

An example of the optical fiber cable is shown in FIG. 1 and is often referred to as a drop cable. An optical fiber cable 7 as a drop cable includes an optical fiber 1 such as one or a plurality of single-core optical fibers or optical fiber tapes, a tension member 2 made of steel wire or aramid resin, and a support wire 3 at the neck. 4 and a sheath 5 having four. In some cases, a notch 6 may be provided on the sheath 5 for the convenience of breaking the sheath 5 and taking out the internal optical fiber 1 or the like.
The dynamic friction coefficient (JIS K 7125) of the outer surface of the sheath of such an optical fiber cable is usually set to 0.15 to 0.4 or more. As described in Patent Document 1, “(if the coefficient of dynamic friction is too low), the cable wound around the bobbin or the drum due to vibration during transportation or laying operation is caused by the collapse or loosening of the cable. The quality of the cable terminal may be deteriorated, and further, a problem such as protrusion of the cable terminal may occur due to loose winding.
JP 2004-272069 A

By the way, as shown in FIG. 2, the above-mentioned optical fiber cable may be laid by inserting one or a plurality of optical fiber cables 7 into the pipe 8. In particular, in recent years when the expansion of an optical fiber network represented by FTTH (Fiber to the home) has progressed, a predetermined optical fiber cable in a pipe line through which a predetermined number of optical fiber cables have already been inserted is exchanged, or A new optical fiber cable has to be inserted additionally. In such a case, in the conventionally known optical fiber cable, it is not necessary to install the fiber optic cable due to friction between the optical fiber cable and the inner wall of the pipe when inserted into the pipe, or friction generated between the existing optical fiber cable. Excessive power is required. For this reason, when inserting the optical fiber cable, a process such as applying a lubricant to the sheath surface each time is required. However, when a lubricant is used, the application process or the like impairs the insertion workability, and even after the insertion, excess lubricant drops from the end of the pipe line and hinders connection work and the like. In some cases, improvements were desired.
Accordingly, an object of the present invention is to provide an optical fiber cable that can be easily inserted into a pipe line and the like without using a lubricant, and that contributes to an improvement in work efficiency of the laying operation.

  The inventors of the present invention have intensively studied the dynamic friction coefficient that has been conventionally considered necessary to maintain the stability of the winding state when wound on a drum or the like, and found an acceptable critical point. We have come up with an optical fiber cable that can significantly improve work efficiency. That is, the optical fiber cable according to claim 1 is an optical fiber cable in which at least an optical fiber and a tension member are collectively covered with a sheath, and a dynamic friction coefficient of the outer surface of the sheath is 0.09 or more and 0.12 or less. It is characterized by.

  An optical fiber cable according to claim 2 is an optical fiber cable in which at least an optical fiber and a tension member are collectively covered with a sheath, and the sheath is made of high-pressure polysynthetic polyethylene resin and 0.18% by weight of a fatty acid amide-based lubricant. It is characterized by being contained at a ratio of 0.32% by weight or less.

An optical fiber cable according to claim 3 is the optical fiber cable according to claim 2, wherein the fatty acid amide-based lubricant is at least one selected from erucic acid amide or oleic acid amide. .

  According to the optical fiber cable of the first aspect, since the dynamic friction coefficient of the outer surface of the sheath is set to the minimum value that can be maintained within the allowable range of the wound state stability, it is possible to move to the pipe without using a lubricant. Therefore, it is possible to provide an optical fiber cable that is easy to insert and that contributes to improving the work efficiency of the laying work.

  According to the optical fiber cable of the second aspect, since the fatty acid amide-based lubricant is contained in a predetermined ratio, it is suitable for setting the dynamic friction coefficient of the outer surface of the sheath to an appropriate value, and when using the existing coating apparatus. It is preferable because the behavior change of the resin material is suppressed within an allowable range.

  As in the optical fiber cable according to claim 3, the fatty acid amide-based lubricant is preferably at least one selected from erucic acid amide or oleic acid amide.

Embodiments of the present invention will be described in detail below with reference to the drawings.
As an embodiment of the present invention, an optical fiber cable 70 shown in FIG. 3 was prepared. An optical fiber cable 70 includes a four-core tape core wire 10, a support wire 30 made of φ1.2 mm steel wire, two tension members 20 made of φ0.5 mm aramid FRP, and a sheath 50 having a neck portion 40. It is configured by batch coating. The long side of the sheath 50 excluding the support line is 3.8 mm, the short side is 2.0 mm, the neck 40 is 0.2 mm in length, the thickness is 0.2 mm, and the outer diameter of the sheath 50 covering the support line 30 is 2.0 mm. The overall height of the optical fiber cable 70 is 6.0 mm.

  Here, in the sheath 50, a dynamic friction coefficient is set to 0.1 by blending 0.30% by weight of a fatty acid amide-based lubricant with a high-pressure polymerizable polyethylene resin. The dynamic friction coefficient is a value measured based on JIS K 7125. Since the optical fiber cable 70 in this embodiment has an appropriate dynamic friction coefficient, it can be laid with a small force when inserted into a pipe line and has good workability. In addition, there is no occurrence of winding collapse that hinders transportation when wound around a drum. In addition, since the blending amount of the lubricant is appropriate, the sheath can be formed without any problem with an existing resin coating apparatus.

  Sixteen types of optical fiber cables equivalent to the optical fiber cable 70 shown in FIG. 3 were prepared and evaluated as examples of the present invention or comparative examples. Between each sample, the configuration of the sheath was changed to change the dynamic friction coefficient. The following evaluation was performed on these samples.

Evaluation 1 (layability)
In order to reproduce the actual installation work, a pipe line with an inner diameter of 16 mm is installed as shown in FIG. 4, and each sample of the optical fiber cable is inserted into the pipe line, and one end is gripped and pulled, and the movement is continued. The force required to measure was measured. The measured force was evaluated as ◯ when the force was 260 g or less, and as x when the force exceeded 260 g.

Evaluation 2 (winding state stability)
As shown in FIG. 5, a sample having a trunk diameter of 306 mm, a trunk width of 300 mm, and a paper bobbin 90 wound with 1000 m of each optical fiber cable with a tension of 24.5 N, transported a land path of 2200 km by a truck, and no collapse occurred. Was marked with ◯, and those with collapse were marked with ×. The cable terminal 71 on the winding start side was led out of the flange 91 from the hole 92 provided in the bobbin flange 91 and fixed to the side surface of the bobbin with the adhesive tape 93. Further, the cable end 72 on the winding end side was fixed by being tied to a middle portion of the cable wound around different turns with a vinyl string.

Evaluation 3 (manufacturability)
When the sheath 50 was provided, a high-pressure polymerizable polyethylene resin coating apparatus, which is a conventional sheath, was used.
The above results are shown in Table 1 below.

Evaluation 4 (Abrasion resistance)
In an environment where the ambient temperature is 23 plus or minus 2 degrees and the humidity is 50 plus or minus 10%, the sheath surface is pressed against # 240 sandpaper with a load of 8.3 N, and a 10 mm span is rubbed at a cycle of 60 cycles / min. The number of times required for the outer skin to wear and the support wire to be exposed was measured.

Comprehensive evaluation Performing the above evaluation, if the laying property or winding state stability is x, the overall evaluation is x. .

  As the above results, samples 5, 6, 7, 8, 9, and 15 having a dynamic friction coefficient of 0.09 or more and 0.12 or less have a comprehensive evaluation of ◯ or more, and can be adopted as examples of the present invention. Furthermore, Samples 5, 6, 7, 8, and 9 in which the lubricant A is blended in the range of 0.18 wt% or more and 0.32 wt% or less to the high-pressure polymerizable polyethylene resin are also easy to manufacture and have a comprehensive evaluation of ◎, which is more preferable It is.

  In addition, the present invention is not limited to the above-described embodiments, and the presence or absence of a support wire, the size of each part, the number of optical fiber cores, a tape core wire, one or a plurality of single core wires, tension The material, dimensions, strength, sheath material, and the like of the member can be changed as appropriate.

It is a cross-sectional explanatory drawing of the conventional optical fiber cable. It is explanatory drawing of the method of inserting an optical fiber cable in a pipe line. It is a transverse section explanatory view showing an embodiment of an optical fiber cable of the present invention. It is explanatory drawing of the method of evaluating the laying property of the optical fiber cable of this invention. It is explanatory drawing of the method of evaluating the winding state stability of the optical fiber cable of this invention, (A) is longitudinal cross-sectional explanatory drawing, (B) is side explanatory drawing.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 4-core tape core wire 20 Tension member 30 Support line 40 Neck part 50 Sheath 70 Optical fiber cable 71 of this invention The cable end 72 of the winding start side The cable terminal 90 of the winding end side Bobbin 91 Bobbin rod 92 Hole 93 provided in the bobbin rod Adhesive tape

Claims (3)

  An optical fiber cable in which at least an optical fiber and a tension member are collectively covered with a sheath, wherein a dynamic friction coefficient of the outer surface of the sheath is 0.09 or more and 0.12 or less.   An optical fiber cable in which at least an optical fiber and a tension member are collectively covered with a sheath, the sheath comprising a high-pressure polysynthetic polyethylene resin and a fatty acid amide-based lubricant at a ratio of 0.18 wt% or more and 0.32 wt% or less. An optical fiber cable comprising:   3. The optical fiber cable according to claim 2, wherein the fatty acid amide-based lubricant is at least one selected from erucic acid amide or oleic acid amide.

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