JP4087014B2 - 2-core cable - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a non-adhesively applied two hearts cables common to envelope the outer periphery of the parallel to Article 2 of the cable core wires.
[0002]
[Prior art]
Conventionally, as an optical fiber cable for indoor wiring for connecting optical communication devices to each other, as shown in FIG. 3, a protective coating (internally made of vinyl chloride resin is provided on the outer periphery of the optical fiber core wire 1 with a high tensile fiber layer 2 interposed therebetween. A two-core optical fiber cable in which two cable cores 4 provided with a sheath 3 are juxtaposed in parallel, and an outer sheath (outer sheath) 5 made of vinyl chloride resin is applied non-adhesively to the outside of the cable core 4 for reinforcement. It has been known. In such an optical fiber cable, a tension member 6 made of a steel wire or the like is usually placed between the cable cores 4 and embedded in the outer jacket 5, and the whole is molded into a tape shape. Yes.
[0003]
By the way, in the above-described two-core flat cable, a so-called pipe extrusion method is used for forming the outer jacket 5 so that the cable core 4 is not crushed by the resin pressure of the extruder.
[0004]
That is, as shown in FIGS. 4 (a) and 4 (b), the nipple 8 having two protruding pipes 7 for inserting the cable core is inserted into the tip of the die 9 to insert the resin 10 into the tip. The jacket 5 is formed by an extruder that is extruded around the cable core 4 in a pipe shape. 4A is a longitudinal sectional view showing the structure of the nipple and die part of the extruder, and FIG. 4B is a view showing the nipple from the front.
[0005]
In the subsequent pulling, the gap between the cable core 4 and the jacket 5 is kept in an optimum state, that is, the jacket 5 does not press the cable core 4 and is kept in close contact. . This is because if there is a gap between the cable core 4 and the jacket 5, the cable core 4 may come out of the jacket 5 when cut into a short length. This is because if the outer sheath 5 is too close, the cable core 4 is pushed by the outer sheath 5 and receives an external force.
[0006]
However, adjusting the degree of pulling down in this way to keep the gap between the cable core 4 and the jacket 5 optimal is that the section of the jacket 5 is not circular and the degree of pulling is not uniform. Because of the large difference in the outer diameter between the cable core and the pipe, it was very difficult because it required a large pull-down. For this reason, it is difficult to stably obtain a two-core flat cable having good characteristics in which the cable core 4 is not pushed by the jacket 5 or the cable core 4 does not come out of the jacket 5. It was.
[0007]
[Problems to be solved by the invention]
As described above, in the conventional two-core flat cable and the manufacturing technology, it is difficult to keep the gap between the cable core and the jacket optimally by adjusting the degree of pulling, and the cable core is pushed by the jacket, Alternatively, there has been a problem that a two-core flat cable having good characteristics in which the cable core does not come out of the jacket and cannot be stably obtained.
[0008]
The present invention has been made to solve such a problem, and it is easy to adjust the gap between the cable core and the jacket, and the cable core is pushed by the jacket or the cable cable from the jacket. never mind will exits, and an object thereof is to provide a two-core cable that can also be 2 Shinpei cable characteristics can be stable.
[0009]
[Means for Solving the Problems]
2-core cable of the present invention comprises comprises a two cables core wires in parallel at intervals, a common envelope city which is extrusion coated on the tape-shaped by a pipe extrusion method on these cable wire heart straight in two-core cable, the jacket of the inner is characterized in that through the projection of plural rows formed in the axial direction in contact with the respective cable core wires.
[0011]
Oite 2 hearts cable having the above configuration, a common envelope for the inner diameter for the cable core wires immediately after extrusion can be highly Sada only small substantially projections, jacket and cable core wires in a small draw down Can be brought into contact with each other. Therefore, it is easy to adjust the gap between the cable core and the jacket by pulling down, and the cable core is not pushed by the jacket or the cable core does not come out of the jacket. A good two-core cable can be obtained stably.
[0012]
Envelope of Common but tape form that has been formed in (sectional flat) If, debit is not uniformly performed, since the inner surface for the envelope of the cable core wires are extruded deformed, withdrawal Toshino The adjustment of the degree is more difficult than when the common jacket is formed in a circular cross section, but since the projections are provided on the inner surface of the sheath, the amount of pull-down is small, and deformation on the cable core The power is reduced. Accordingly, it is possible to easily and stably obtain a two-core flat cable having good characteristics in which the cable core is not pushed by the jacket, or conversely, the cable core is not pulled out from the jacket. Become.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view showing a two-core flat optical fiber cable according to an embodiment of the present invention.
[0014]
In FIG. 1, this two-core flat type optical fiber cable has two cable cores 14 each provided with a protective coating 13 made of vinyl chloride resin or the like on the outer periphery of the optical fiber core 11 with a high tensile fiber layer 12 interposed therebetween. The tension members 15 made of steel wire or the like are spaced apart from each other so that the center thereof is located on the same plane as the center of each cable core 14, and a vinyl chloride resin is disposed on the outer periphery thereof. It has a structure in which a tape-like common outer cover 16 made of, for example, is applied.
[0015]
The common jacket 16 is formed by using a pipe type extruder having a nipple as shown in FIGS. 2 (a) and 2 (b). That is, two cable wire core insertion pipes 18 are provided at the tip of the nipple 17 of this pipe type extruder, and the tip is inserted to the tip of the die 19. Further, four V-grooves 20 extending in the axial direction are provided at substantially equal intervals in the circumferential direction on the outer peripheral surface of each of the cable core insertion pipes 18. 2A is a longitudinal sectional view showing the structure of the nipple and the die part of the extruder, FIG. 2B is a view showing the nipple from the front, and in these drawings, 21 indicates two cables. A tension member insertion hole opened between the wire core insertion pipes 18 and an extrusion material 22.
[0016]
In such a pipe type extruder, the common jacket 16 is formed on the two cable cores 14 and on the inner surface of each cable core 14, four protrusions 23 a, 23 b, 23 c corresponding to the V-groove 20. In the present invention, the protrusions 23a, 23b, 23c, and 23d are pulled down so as to be in contact with the cable core 14, respectively. As a result, as shown in FIG. 1, the three protrusions 23a, 23b, and 23c are in contact with each cable core 14, and the remaining one protrusion 23d is pulled toward the tension member 15 and adjacent to the protrusion 23a, A part of the inner surface with respect to 23c is formed in a shape in contact with the cable core. The reason why a part of the inner surface on the tension member 15 side is in contact with the cable core is that the outer surface of the jacket is irregular (tape-shaped), so that a larger pulling force acts than the other part.
[0017]
In such a two-core cable, the extrusion inner diameter of the common jacket 16 with respect to the cable core 14 is substantially smaller than that of the conventional one by the depth of the V-groove 20, so And the cable core 14 can be brought into contact with each other, and the force by which the jacket 16 presses the cable core can be reduced by deformation due to non-uniformity of the withdrawal. Therefore, the degree of pulling can be easily adjusted, and the cable core is not pushed by the jacket, or conversely, the cable core is not pulled out of the jacket, and a two-core cable with good characteristics can be easily obtained. And can be obtained stably.
[0018]
The above example is an example in which the present invention is applied to a two-core flat type optical fiber cable. However, the present invention is not limited to such an example, and can be widely applied to various other two-core cables. Needless to say. Further, the shape, number, position, and the like of the grooves provided on the outer peripheral surface of the pipe are not particularly limited to the above example, and may be appropriately determined within a range in which the above-described effects can be obtained.
[0019]
【Example】
Next, examples of the present invention will be specifically described.
[0020]
As an example cable core, a coated optical fiber core with an outer diameter of 2.0 mm obtained by extrusion-coating vinyl chloride resin on the outer periphery of an optical fiber core with an outer diameter of 0.9 mm along with an aramid fiber. In addition, a steel wire having an outer diameter of 0.7 mm was used as the tension member, and a common jacket was applied by the pipe type extruder shown in FIG. 2 (depth of V groove on the nipple outer peripheral surface 0.2 mm, width 0.2 mm). An optical fiber cable was manufactured. For the jacket material, use the same vinyl chloride resin as that used for the protective coating of the coated optical fiber so that the outer shape is a tape with a maximum width of about 7.0 mm and a maximum thickness of about 4.0 mm. In addition, the inner protrusion formed by the V groove on the outer peripheral surface of the nipple was pulled down so as to be in contact with the coated optical fiber. The distance between the centers of the two coated optical fibers is about 3.6 mm, and the distance between the centers of the steel wires and the coated optical fibers is about 1.8 mm.
[0021]
The obtained optical fiber cable had good and stable transmission characteristics without increasing loss due to side pressure. Further, the coated optical fiber core wire did not come out from the common jacket even when it was cut short.
[0022]
【The invention's effect】
As described above, according to the present invention, since the common jacket is extruded into a shape having a plurality of protrusions on the inner side with respect to each cable core, The cable cores can be properly brought into contact with each other, and the effect of the deforming force of the jacket on the cable core due to uneven pulling can be reduced. Therefore, it is possible to easily and stably obtain a two-core cable with good characteristics in which the cable core is not pushed by the jacket or, conversely, the cable core does not come out of the jacket. .
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a two-core flat optical fiber cable according to an embodiment of the present invention.
FIGS. 2A and 2B are diagrams showing a configuration of a main part of a pipe-type extruder used in the present invention, wherein FIG. 2A is a longitudinal sectional view showing a structure of a nipple and a die part, and FIG.
FIG. 3 is a cross-sectional view showing an example of a conventional two-core flat optical fiber cable.
4A and 4B are diagrams showing a configuration of a main part of a pipe-type extruder used for manufacturing a conventional two-core flat type optical fiber cable, wherein FIG. 4A is a longitudinal sectional view showing the structure of a nipple and a die portion, and FIG. The figure which showed from the front.
[Explanation of symbols]
11 ......... Optical fiber core 12 ......... High tensile strength fiber layer 13 ......... Protective coating 14 ......... Cable core 16 ......... Common sheath 17 ...... Nipple 18 ......... Cable core insertion General-purpose pipe 19 ......... Die 20 ......... V-groove 23 ......... Protrusions

Claims (3)

And two cables core wires in parallel at intervals in two-core cable comprising a common enveloping city which is extrusion coated on the tape-shaped by a pipe extrusion method on these cables core wires straight,
The two-core cable, wherein an inner side of the jacket is in contact with each cable core through a plurality of protrusions formed in the axial direction. 2. The two-core cable according to claim 1 , wherein the cable core is formed by coating an outer periphery of an optical fiber. 2. The two-core cable according to claim 1 , wherein the cable core is formed by providing a protective coating on the outer periphery of the optical fiber core via a high strength fiber layer.

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