JP2580313Y2 - Optical cable - Google Patents

Description

[Detailed description of the invention]

[0001]

In the present invention, a plastic flexible square groove, in which an optical fiber ribbon or an optical fiber core is accommodated, has good sliding and minimizes the occurrence of distortion due to bending or the like. It relates to an optical cable.

[0002]

2. Description of the Related Art In recent years, in the technical field of optical cables, the number of optical fiber cores is required to be higher, and a cable having an optical fiber core number of 3000 to 4000 or more is desired.

[0003] From such a viewpoint, the present applicant has proposed a long flexible angular groove having a square groove, and a plurality of optical fiber tapes are placed in the groove of the square groove.
An optical cable in which a plurality of the square grooves are twisted in multiple layers around the outer periphery of a tension member has been proposed (Japanese Patent Application No. 02-31177).

[0004]

However, in an optical cable in which such a large number of square grooves are gathered, if the optical cable is bent during transportation or installation, the optical fiber tape in the groove may be distorted. I understood. Measures to alleviate this bending distortion include: (1) increasing the groove of the angular groove so that the optical fiber ribbon or the like can easily move in the groove, and providing sufficient clearance, (2) or the optical fiber. In order to improve the slip of the optical fiber ribbon, it is conceivable to apply a lubricant or the like to the surface of the optical fiber ribbon or the like. However, increasing the clearance of the angular groove is not preferable because it is against the densification and ultra-multi-core of the optical cable.
On the other hand, in the case of applying a lubricant to the surface of an optical fiber tape or the like, there is a problem in that the application itself is quite difficult, resulting in application unevenness and inevitable contamination around the device.

[0005] The present invention has been made in view of such a point.

[0006]

Means for Solving the Problems The present invention relates to an outer peripheral section.
Perimeter of tension member consisting of a linear striated surface
One or more optical fiber ribbons or optical fibers.
The left and right standing wall parts where the fiber core wire is stored in the groove are almost
One or more vertical flexible angle grooves
Twisted as several layers, and the first layer of the square groove
The bottom side is the outer circumference of the center tension member
An optical cable of a direct contact type , wherein the square groove is made of plastic, and a friction coefficient control material is added to the plastic material, so that the entire outer surface and the entire inner surface of the square groove have a low friction coefficient. An optical cable characterized in that:

[0007]

The function of reducing the friction of the angular groove itself is not limited to the optical fiber ribbon or the optical fiber core housed in the groove, but also between the angular groove and the tension member and between the angular grooves. Since the movement is performed smoothly, the occurrence of distortion is effectively suppressed. Ma
The left and right standing walls of the corner groove are almost vertical
When twisting square grooves, each adjacent square group
There is a gap above the standing wall between the
Is obtained.

[0008]

FIG. 1 shows an embodiment of an optical cable according to the present invention. In the figure, 1 is a left and right standing having a square groove 2.
The installation wall portion is a long flexible angle groove having a substantially vertical shape, and a plurality of optical fiber tape cores 3 such as five as shown in FIG. For example, in the case of an optical cable having a two-layer structure, whether the outer peripheral section centered on the innermost corner groove 1 is a circular linear body
The outermost corner groove 1 is twisted and wound on the cable core, and the sheath 5 is applied to the outer sheath.

In the present invention, the above-mentioned square groove 1 is formed of a plastic such as polyethylene, nylon, PBT or polypropylene, and at the time of this formation, a friction coefficient controlling material is added to the plastic material to form the square groove having a low friction coefficient. And When the base material is polyethylene, examples of the friction coefficient controlling material include a slip agent such as fatty acid amide and an anti-blocking agent such as natural silica. These are added alone or in combination to obtain a desired low coefficient of friction.

As an example of a specific composition, 0.01 to 1 part by weight of fatty acid amide and 0.01 to 1 part by weight of natural silica are added to 100 parts by weight of polyethylene.
If necessary, an antistatic agent and the like are added as other additives.

The coefficient of friction between the angular groove 1 obtained in this way and the UV-coated optical fiber tape core wire 3 housed in the groove 2 was examined, and the value (μ ₁₃ ) was obtained.
Was 0.01, and the friction coefficient (μ ₁₁ ) of the square grooves 1 and 1 was 0.05. In the conventional angular groove without addition of the friction coefficient controlling material, in a corresponding friction coefficient mu ₁₃ 0.1, also a corresponding friction coefficient mu ₁₁ 0.3, compared to the present invention The size was 10 times or more. In the friction coefficient mu ₁₃ of the angle groove and the optical fiber ribbon, for example, it is determined by the following method. First, as shown in FIG. 3, a sample angular groove 11 is wound around a cylindrical body 16 having a radius R.
The winding angle θ is, for example, 2π, and the optical fiber tape core 13 to be measured is housed in the groove of the angular groove 11, as shown in FIG. A load cell 17 was attached to the end, and the tension F when pulling the optical fiber tape 13 was measured. Then, by calculating by introducing the measured data to the relational expression of _{μ 13 θ = In (F /} W), the friction coefficient _{mu 13} is determined.

When the optical cable of the present invention using the square groove 1 is bent upward in the figure, for example, as shown in FIG. Is acted upon by the force of compression
Naturally, even if the optical fiber ribbon 3 is housed in the groove 2 due to these forces, if the friction with the wall surface of the groove 2 is large, a large distortion will occur to follow the movement. In the present invention, since the friction coefficient of the angular groove 1 is small as described above, the angular groove 1 and the optical fiber ribbon 3, the adjacent (left and right or up and down) angular grooves 1 and 1, the angular groove 1 Since an extremely good sliding is obtained between the tension member 1 and the tension member 4, for example,
Strain at each part is well absorbed and improved.

Although the corner groove 1 in the above embodiment has a single groove, the present invention is not limited to this, and the corner groove 1 has several grooves connected in a comb shape. In the case of using, it is of course applicable. Further, the core wire accommodated in the angular groove 1 is not limited to the above-described optical fiber tape core wire 3 but may be a normal optical fiber core wire.

[0014]

As is apparent from the above description, in the optical cable of the present invention, one or two or more optical fiber tapes or optical fiber cores are erected on the left and right sides in the groove.
A plurality of flexible angular grooves whose wall portions are substantially vertical are formed into one or more layers, and a linear striated body having a circular outer peripheral section centered at least on the bottom side of the first layer of the angular grooves.
In direct contact with the outer circumference of the tension member consisting of
A twisted optical cable, wherein the square groove is made of plastic, and a friction coefficient control material is added to the plastic material so that the entire outer surface and the entire inner surface of the square groove have a low friction coefficient, so that the groove is formed. The movement between the square groove and the tension member, between the square grooves, and the like, as well as the optical fiber tape core wire housed inside, is smoothly performed, and the occurrence of distortion is effectively suppressed. Of course, as a result, in the optical cable of the present invention, a large clearance is unnecessary in the groove of the square groove, so that it is possible to increase the density of the optical fiber, to increase the number of optical fibers, and to use an optical fiber tape. Since it is not necessary to apply a lubricant to the surface of the device, uneven application and stains around the device are basically eliminated. Also, the left and right standing walls of the corner groove
Since the part is almost vertical, twisted square grooves
At the time, on the upper side of the standing wall portion between adjacent corner grooves
Since there is a gap, the entire twisted body of each square groove is
Even so, moderate flexibility is obtained.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing one embodiment of an optical cable according to the present invention.

FIG. 2 is a perspective view showing a square groove used in the optical cable of FIG. 1 and an optical fiber ribbon accommodated in the groove.

FIG. 3 is a schematic explanatory view showing an apparatus system for obtaining a friction coefficient.

FIG. 4 is a longitudinal sectional view showing the optical fiber ribbons accommodated in the angular grooves in the apparatus system of FIG. 3;

FIG. 5 is a partially cutaway side view showing a bent state of the optical cable according to the present invention.

[Explanation of symbols]

 1 square groove, 2 groove, 3 optical fiber ribbon, 4 tension member, 5 sheath,

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yoshiyuki Sato 1440, Mukurosaki, Sakura-shi, Chiba Fujikura Electric Wire Co., Ltd.Sakura Plant (72) Inventor Hideo Suzuki 1440 Mukurosaki, Sakura City, Chiba Prefecture Fujikura Electric Cable Co., Ltd.Sakura Plant (72) Inventor Shigeru Tomita 1-6 Uchisaiwaicho, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Corporation (56) References JP-A-55-45087 (JP, A) JP-A-1-270018 (JP, A) JP-A-2-272509 (JP, A) JP-A-61-272212 (JP, A) -46416 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) G02B 6/44 366

Claims (1)

(57) [Scope of request for utility model registration] 1. A tenn comprising a linear filament having an outer peripheral cross section.
One or two or more optical fiber
Left or right with loop core or optical fiber core stored in groove
Flexible angle groove where the vertical wall portion of the is almost vertical
Are twisted as one layer or a plurality of layers, and
The bottom surface of the first layer of the groove is the center tension member.
An optical cable in direct contact with a circular outer periphery of a bar , wherein the square groove is made of plastic, and a friction coefficient control material is added to the plastic material, and the entire outer surface and the entire inner surface of the square groove are provided. An optical cable characterized by having a low coefficient of friction.