WO2019009238A1

WO2019009238A1 - Optical fiber cable

Info

Publication number: WO2019009238A1
Application number: PCT/JP2018/025043
Authority: WO
Inventors: 太郎石田; 一史野地; 賢吾田邉
Original assignee: 昭和電線ケーブルシステム株式会社
Priority date: 2017-07-03
Filing date: 2018-07-02
Publication date: 2019-01-10
Also published as: JP7117302B2; CN110914729A; JPWO2019009238A1

Abstract

The present invention provides an optical fiber cable capable of suppressing increased loss during wiring work and breakage. This optical fiber cable includes an optical fiber, a center tensioner, an outer tensioner, and an outer cover. The center tensioner is made of a fibrous body and is provided along the length of the optical fiber. The outer tensioner is made of a fibrous body and is provided along the length of the optical fiber around the optical fiber and the center tensioner. The outer cover is provided around the outer tensioner. Here, the fineness of the outer tensioner is less than that of the center tensioner.

Description

Fiber optic cable

The present invention relates to optical fiber cables.

Along with the start of high-speed communication services, small cells having a communication area smaller than that of macro cells are installed in addition to macro cells as mobile base stations that are mobile station radio stations. Small cells are installed to suppress deterioration in communication quality in places where there are many users (such as downtown areas such as stations and commercial facilities) and places where radio waves are difficult to reach (such as underground malls). Small cells include nanocells and picocells installed in places such as buildings, underground malls, and the inside of buildings, and include femtocells installed in places such as stores, offices, and general households.

JP 2008-015414 A JP, 2005-062744, A

Conventionally, in a macro cell, a cable aggregation type optical fiber cable is used. The cord assembly type optical fiber cable is low in handleability because of its high rigidity. For this reason, it is not easy to perform the wiring work of the small cell using the cord assembly type optical fiber cable.

For example, an optical fiber cable is formed by transversely winding an aramid fiber in an assembly composed of an optical fiber core wire, an inter-fiber interposition and a central buffer material. Here, in the optical fiber cable, the outer peripheral side has a higher density than the inner peripheral side. For this reason, when the optical fiber cable is bent, the loss (transmission loss) may increase in the optical fiber cable. In addition, if the optical fiber cable is twisted, breakage may occur, such as disconnection of the optical fiber cable.

In particular, when the optical fiber cable is bent in the small cell wiring operation or when the optical fiber cable is twisted, the above problem may become apparent.

Therefore, the problem to be solved by the present invention is to provide an optical fiber cable which suppresses an increase in loss in wiring work and is less likely to be damaged.

The optical fiber cable of the present invention comprises an optical fiber core wire, a central tension member, a peripheral tension member and a jacket. The central tension member is formed of a fiber body and is provided vertically to the optical fiber core. The peripheral tension member is formed of a fiber body, and is provided vertically to the optical fiber core wire and the optical fiber core wire around the central tension member. A jacket is provided around the peripheral tension member. Here, the fineness of the peripheral tension members is smaller than the fineness of the central tension member.

According to the present invention, it is possible to suppress an increase in loss in wiring work and provide an optical fiber cable which is less likely to be damaged.

FIG. 1 is a view schematically showing the main part of the optical fiber cable according to the embodiment. FIG. 2: is a figure which shows typically the principal part of the optical fiber cable concerning the modification of embodiment.

Embodiments of the invention will be described using the drawings. The invention is not limited to the contents of the drawings. The drawings show the outline, and the dimensional ratio of each part does not necessarily coincide with the actual one. In addition, about the same component, the same code | symbol is attached | subjected and the overlapping description is abbreviate | omitted suitably.

[A] Configuration FIG. 1 is a view schematically showing a main part of an optical fiber cable according to an embodiment. FIG. 1 shows a cross section (xz plane) in which the axial direction (y direction) of the optical fiber cable 1 is orthogonal.

As shown in FIG. 1, the optical fiber cable 1 is circular in cross section, and includes an optical fiber core wire 10, a tension member 20, and a jacket 30. Each part which comprises the optical fiber cable 1 is demonstrated one by one.

[A-1] Optical fiber 10
The optical fiber 10 is circular in cross section. The optical fiber core wire 10 is configured, for example, by sequentially providing a primary coating (not shown) and a secondary coating (not shown) on an optical fiber (not shown). In the optical fiber, for example, the core and the cladding are formed of quartz glass. The primary coating is formed of, for example, an ultraviolet curable resin. The secondary coating is formed of, for example, a thermoplastic resin.

[A-2] Tension member 20
The tension member 20 is a linear tensile member, and is provided as a reinforcing wire for reinforcing the optical fiber core wire 10. The tension member 20 protects the optical fiber core wire 10 by functioning as a cushion that reduces an impact applied to the optical fiber core wire 10 when an external force such as a side pressure is applied to the optical fiber cable 1, for example.

In the present embodiment, the tension member 20 includes a central tension member 21 and a peripheral tension member 22. The central tension member 21 is a fiber body, and a plurality of fibers (not shown) are bundled so as to have a circular outer shape. The peripheral tension member 22 is, like the central tension member 21, a fiber body in which a plurality of fibers are bundled. Here, the peripheral tension member 22 is provided around the optical fiber core 10 and the central tension member 21, and a plurality of fibers (not shown) are bundled so that the outer shape becomes circular.

In the tension member 20, the central tension member 21 and the peripheral tension member 22 are provided vertically to the optical fiber core 10. That is, the axial direction of the central tension member 21 and the axial direction of the peripheral tension member 22 are along the axial direction (y direction) of the optical fiber core wire 10.

In the tension member 20, the fineness of the peripheral tension member 22 is smaller than the fineness of the central tension member 21. That is, in the optical fiber cable 1 of the present embodiment, the density on the outer peripheral side is lower than that on the inner peripheral side. Therefore, for example, even when the optical fiber cable 1 is bent in the small cell wiring operation, it is possible to suppress an increase in communication loss in the optical fiber cable 1. In addition, for example, even when twisting occurs in the optical fiber cable 1 in the wiring operation of the small cell, the occurrence of breakage (breakage or the like) in the optical fiber cable 1 can be suppressed. As a result, it is possible to improve the reliability of the optical fiber cable 1.

Here, the fineness of the central tension member 21 is preferably 5000 denier or more and 10000 denier or less. The fineness of the peripheral tension member 22 is preferably 500 deniers or more and 3000 deniers or less. Thereby, it is possible to further enhance the above effect.

Further, in the tension member 20, it is preferable that the central tension member 21 and the peripheral tension member 22 be formed of, for example, aramid fibers. Thereby, since the optical fiber cable 1 becomes easy to bend, the efficiency of the wiring operation can be enhanced.

[A-3] Outer cover 30
The jacket 30 is a sheath and is provided around the peripheral tension member 22. The jacket 30 is provided to protect the optical fiber 10.

The jacket 30 is preferably formed using flame-retardant polyethylene (which does not burn in a test according to JIS C3521). Thereby, the action of the dehydration endothermic reaction of metal hydroxides such as magnesium hydroxide and aluminum hydroxide contained in the flame retardant polyethylene can exert an autodigestive effect.

Moreover, it is preferable that the thermal contraction rate of the outer jacket 30 is 2% or less. The jacket 30 shrinks when a temperature difference repeatedly occurs in the environment where the optical fiber cable 1 is installed. The loss of the optical fiber cable 1 may increase due to the stress applied to the optical fiber core wire 10 along with this. However, when the thermal contraction rate of the jacket 30 is 2% or less, the jacket 30 is difficult to shrink even when the temperature difference is repeatedly generated. As a result, the loss of the optical fiber cable 1 can be effectively suppressed. Specifically, when the temperature cycle test (according to JIS C 6851, temperature condition: -20 to + 60 ° C, number of cycles: 3 times), increase in transmission loss should be 0.2 dB / km or less Can. In addition, when measuring said thermal contraction rate, the test piece which cut | disconnected the optical fiber cable 1 at 1 m was first prepared. And after testing the test piece in a thermostat (100 degreeC) for 1 hour, the test was done by leaving it to stand at normal temperature (20 degreeC) for 1 hour. And about the test piece, the ratio of the length after a test to the length before a test was computed as a heat contraction rate.

[B] Manufacturing Method An outline of a manufacturing method for manufacturing the optical fiber cable 1 of the present embodiment will be described.

When manufacturing said optical fiber cable 1, an extrusion molding apparatus (illustration omitted) is used, for example. Specifically, the optical fiber 10 with the tension member 20 attached around is passed through a die (not shown) of the extrusion molding apparatus. In the present embodiment, as described above, the central tension member 21 and the peripheral tension member 22 as the tension members 20 are vertically attached to the optical fiber 10. Then, in a state in which the optical fiber 10 with the tension member 20 attached to the periphery is fed from the die, the resin constituting the outer jacket 30 is pushed out from the die. Thereby, the optical fiber cable 1 is manufactured by forming the jacket 30 around the peripheral tension member 22.

[C] Modified Example FIG. 2 is a view schematically showing a main part of an optical fiber cable according to a modified example of the embodiment. In FIG. 2, as in FIG. 1, a cross section (xz plane) in which the axial direction (y direction) of the optical fiber cable 1 is orthogonal is shown.

In the above embodiment, although the case where the number of the optical fiber cable 10 is single in the optical fiber cable 1 is shown (see FIG. 1), it is not limited thereto. As shown in FIG. 2, in the optical fiber cable 1, a plurality of (for example, two) optical fiber cores 10 may be provided.

Examples of the optical fiber cable 1 and comparative examples will be described using Tables 1 to 3.

Table 1 shows the relationship of each example of the optical fiber cable 1. Table 2 shows the result of the 180 ° bending test for each example of the optical fiber cable 1, and Table 3 shows the result of the torsion test. In Tables 1 to 3, Examples A1 to E4, Example F3, and Example F5 are Examples, and Examples F1 and X are Comparative Examples. In addition, in order to facilitate understanding, in the description of each example, each part is given a reference numeral (see FIG. 1) as in the above embodiment.

[Preparation of sample]
The samples of each example were prepared as follows.

(Example A1)
In Example A1, as the optical fiber core 10, the core and the cladding are formed of quartz glass, the primary coating is formed of an ultraviolet curable resin, and the secondary coating is formed of a thermoplastic resin (the outer Diameter: about 0.9 mm). Then, as the central tension member 21 and the peripheral tension member 22, a fiber body having fineness shown in Table 1 and formed of aramid fibers was used. Moreover, the outer cover 30 was formed using the flame retardant polyethylene.

Specifically, one central tension member 21 is disposed with the optical fiber core 10 vertically. Then, a plurality of (for example, 12) peripheral tension members 22 are vertically arranged around the optical fiber 10 and the central tension member 21. Thereafter, an outer cover 30 made of flame-retardant polyethylene was formed around the peripheral tension member 22 by extrusion molding. Here, as the flame retardant polyethylene, one having 50 to 100 parts by mass of magnesium hydroxide blended with 100 parts by mass of EEA (ethylene-ethyl acrylate copolymer) and PE (polyethylene) base resin is used. It was. By blending a large amount of magnesium hydroxide, the flowability of the resin is reduced, and distortion is unlikely to remain at the time of extrusion molding, so the amount of shrinkage of the jacket 30 by heating can be reduced.

(Example A3 to Example F5)
In each of the examples A3 to F5, the optical fiber cable 1 is manufactured in the same manner as the example A1, except that the fiber body having the fineness shown in Table 1 is used as the central tension member 21 and the peripheral tension member 22. did.

(Example X)
In Example X, a fiber body having the fineness shown in Table 1 was used as the peripheral tension member 22 without providing the central tension member 21. An optical fiber cable 1 was produced in the same manner as in Example A1 except this point. That is, in Example X, the tension members 20 are configured such that the fineness is uniformly distributed in the cross section.

[Evaluation]
About the sample of each case, as shown in Table 2 and Table 3, the 180 degree bending test and the torsion test were done and evaluated.

(180 ° bending test)
The 180 ° bending test was performed by the method defined in “JIS C 6851”. Specifically, U-bending was performed so that the sample of each example had an angle of 180 degrees around the mandrel (diameter 100 mm). The sample was subjected to reverse U-bending and then returned to the straight state. Here, the U-bending, the reverse U-bending, and the operation of returning to the straight state were repeated 10 cycles. And about the sample of each case, the loss increase amount was measured in the state which is performing the 180 degree bending test, and the largest loss increase amount was calculated | required.

In Table 2, it showed based on the reference | standard shown below about the result of the largest loss increase amount calculated | required by the 180 degree bending test.
・・・ ... When the maximum loss increase is 0.07 dB or less ○ ... When the maximum loss increase is more than 0.07 dB and 0.08 dB or less Δ ... More than .08 dB and less than 0.1 dB × · · · When the maximum increase in loss exceeds 0.1 dB

(Torsion test)
The torsion test was performed by the method defined in "JIS C 6851". Specifically, the sample was mounted on a stationary clamp and a rotary clamp in a twisting apparatus. Here, the sample was mounted such that the span length of the sample was 250 mm. The sample was then loaded with tension (40 N) to keep the sample in a straight state. In this state, after rotating the clamp on the rotating side clockwise by 180 ° in the twisting device, the clamp was returned to the initial position. Then, the clamp on the rotating side was rotated 180 degrees counterclockwise, and then returned to the initial position. These operations were repeated 20 cycles.

Table 3 shows the results of the torsion test based on the criteria shown below.
・・・ ... no disconnection of the optical fiber core 10 and the transmission loss is 0.01 dB / km or less ○ ... no disconnection of the optical fiber core 10 and the transmission loss 0.01 dB / km 0.05 ····························································· Optical When the fiber 10 is broken

[Evaluation summary]
As shown in Table 1, Examples A1 to F5 differ from Example X in that the tension members 20 include a central tension member 21 and a peripheral tension member 22. In each of Examples A1 to F5 except Example F1 (Examples A1 to E4, Example F3, and Example F5), the fineness of peripheral tension member 22 is smaller than the fineness of central tension member 21. For this reason, as shown in Table 2, each example (Example A1 to Example E4, Example F3, Example F5) except Example F1 among Example A1 to Example F5 is compared with Example F1 and Example X as shown in Table 2. As shown in Table 3, damage is less likely to occur while the increase in loss is suppressed. On the other hand, when the fineness of the tension member 20 is uniformly distributed uniformly as in Example X, and as in Example F1, the fineness of the peripheral tension member 22 rather than the fineness of the central tension member 21. The above effect can not be achieved when the value of is larger.

As shown in Table 1, in Example B2, Example B4, Example B2, Example C2, Example C3, Example C4, Example D3, Example E2, Example E3, and Example E4, the denier of central tension member 21 is 5,000 deniers. As described above, the deniers are 10000 deniers or less, and the fineness of the peripheral tension members 22 is 500 deniers or more and 3000 deniers or less. For this reason, as shown in Table 2, each of the above-described examples can further effectively suppress an increase in loss in the wiring operation. Further, as shown in Table 3, each of the above-described examples can more effectively suppress the occurrence of breakage.

Specifically, the sample in each example has a circular cross-section in a flat state in the “bent portion” bent in the 180 ° bending test, and thus the optical fiber core wire 10 located at the center in the optical fiber cable 1 Is stressed. However, when the fineness of the peripheral tension member 22 is in the range of 500 deniers to 3000 deniers, the side pressure applied in the radial direction in the optical fiber 10 becomes smaller, so the stress applied to the optical fiber 10 becomes smaller. . When the fineness of the central tension member 21 is not less than 5000 denier and not more than 10000 denier, the curvature of the optical fiber core wire 10 does not become larger than the predetermined curvature in the sample bent in the 180 ° bending test. As a result, the loss increase amount of the optical fiber cable 1 can be reduced by setting the fineness of the central tension member 21 and the fineness of the peripheral tension member 22 in the ranges defined above.

In addition, the samples of each example are more centered on the peripheral tension member 22 than before the torsion test due to the “torsion deformation” caused by the torsion test. However, when the fineness of the peripheral tension member 22 is in the range of 500 deniers to 3000 deniers, the side pressure applied in the radial direction in the optical fiber 10 is reduced, so that the transmission loss can be reduced. In addition to this, by setting the fineness of the central tension member 21 and the fineness of the peripheral tension member 22 in the range defined above, the rigidity of the optical fiber cable 1 can be lowered, so that good flexibility can be obtained. it can.

In order to reduce the cost, it is preferable that the center tension member 21 and the peripheral tension member 22 have a high fineness. When the difference between the fineness of the central tension member 21 and the fineness of the peripheral tension member 22 is extremely large, eccentricity of the optical fiber core 10 may occur when a large stress is applied to the optical fiber cable 1 . Therefore, it is preferable that the fineness of the central tension member 21 and the fineness of the peripheral tension member 22 be in the above-mentioned range.

Reference Signs List 1 optical fiber cable 10 optical fiber core 20 tension member 21 center tension member 22 peripheral tension member 30 jacket

Claims

Optical fiber core wire,
A central tension member formed of a fiber body and provided longitudinally to the optical fiber core wire;
A peripheral tension member formed of a fiber body and provided vertically to the optical fiber at the periphery of the optical fiber and the central tension member;
And a jacket provided around the peripheral tension member,
An optical fiber cable characterized in that the fineness of the peripheral tension member is smaller than the fineness of the central tension member.
The fineness of the central tension member is not less than 5000 denier and not more than 10000 denier,
The fineness of the peripheral tension member is 500 deniers or more and 3000 deniers or less.
The optical fiber cable according to claim 1.
The central tension member and the peripheral tension member are formed of aramid fibers,
The optical fiber cable according to claim 1 or 2.
The jacket is formed of flame-retardant polyethylene and has a thermal shrinkage of 2% or less.
The optical fiber cable according to any one of claims 1 to 3.