JP2003295016A - Multiple core optical fiber cable - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the bending characteristics of an optical fiber cable using grooved spacers. <P>SOLUTION: The spacer 1<SB>1</SB>is composed of an outer layer 1A<SB>1</SB>consisting of a solid high-density polyethylene resin (HDPE) having a groove 2 on the outer periphery and an inner layer 1B<SB>1</SB>consisting of a foamed resin material inserted and holding a tension member 4 inserted at its center, to make the bending rigidity G<SB>1</SB>of the spacer 1<SB>1</SB>G<SB>1</SB>≤9.0 [N.m<SP>2</SP>]. A coating 6<SB>1</SB>is provided with an outer layer 6A<SB>1</SB>consisting of a straight chain low-density polyethylene resin (LLDPE) and an inner layer 6B<SB>1</SB>consisting of a metal foil and is formed by subjecting the inner layer 6B<SB>1</SB>to bellows-like corrugating, by which the bending rigidity G<SB>2</SB>of the coating 6<SB>1</SB>is made into G<SB>2</SB>≤12.0 [N.m<SP>2</SP>]. As a result, the bending rigidity G<SB>0</SB>of the entire part of the multiple core optical fiber cable is set at G<SB>0</SB>≤21.0 [N.m<SP>2</SP>]. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-core optical fiber cable which holds a large number of optical fiber cores by using a grooved spacer.

[0002]

2. Description of the Related Art An example of a general multi-core optical fiber cable having a grooved spacer is shown in FIG. In this multi-core optical fiber cable, a plurality of optical fiber cores (tape cores) 3 which are bundled in a tape shape are stacked and held in the respective spiral grooves 2 formed on the outer periphery of the spacer 1. . Then, the tension member 4 made of steel stranded wire or the like is inserted through the center of the spacer 1. Further, the spacer 1 with a spiral groove is covered with a cover consisting of a press winding tape 5 and a cover 6. In this way, the multi-core optical fiber is constructed.

[0003]

In the multicore optical fiber cable having the above structure, the spacer 1 is made of a solid body made of a resin material such as high density polyethylene (HDPE), and the bending rigidity of the multicore optical fiber is It is big. Therefore, it is difficult to bend the multi-core optical fiber cable with a small radius of curvature, and improvement in workability is desired.

Particularly in recent years, in order to cope with an increase in the amount of information to be transmitted, the number of optical fibers held by one multi-core optical fiber cable has been increased, for example, from several hundreds to 1,000. As a result, the cable diameter becomes large, and the above problem becomes more remarkable.

The present invention has been made paying attention to such a point, is excellent in weight saving and bending characteristics, and is excellent in workability that enables laying along a curved path having a relatively small radius of curvature. It is intended to provide a multi-fiber optical fiber cable.

[0006]

In the present invention, in order to achieve the above object, a cable is constructed as follows.

That is, a tension member is inserted through the center, and a spacer is provided on the outer periphery of which a groove is provided along substantially the axial direction. The spacer is held after the optical fiber core wire is inserted and held in the groove. A multi-core optical fiber cable covered with a coating, wherein the spacer is an outer layer made of a solid high-density polyethylene material (HDPE) having the groove on the outer periphery, and a foamed resin in which the tension member is inserted and held in the center. Since the spacer has an inner layer made of a material, the flexural rigidity G _{1 of the} spacer is G ₁ ≦ 9.0 [N · m ² ], and the coating is a solid linear low-density polyethylene material (LLDPE). The bending rigidity G ₂ of this coating is G ₂ ≦ 12.0 [N.
m ² ], and the bending rigidity G _{0 of the} entire cable is G ₀ ≤21.
It was set to 0 [N · m ² ].

Further, the tension member is inserted through the center.
In addition, a groove is provided on the outer periphery along the substantially axial direction.
It has a spacer and holds the optical fiber core in the groove.
Then, a multi-fiber optical fiber is formed by covering the spacer with a coating.
Cable, the spacer having a plurality of
Full linear low density polyethylene material (L
LDPE) outer layer and the tension member in the center.
Full linear low density polyethylene material with a bar inserted and retained
(LLDPE) or full ultra low density polyethylene material
(VLDPE) inner layer
Flexural rigidity G of spacer₁To G₁≦ 6.0 [N · m²]When
The above-mentioned coating is a solid linear low-density polyethylene material.
(LLDPE) outer layer and metal foil inner layer
And corrugated to the inner layer
Then, the bending rigidity G of this coating₂To G₂≦ 12.0 [N ・
m²], And bending rigidity G of the entire cable₀To G₀≤18.
0 [N ・ m ²].

The above-mentioned stiffnesses G ₁ , G ₂ and G ₀ are all measured values at a temperature of 20 ± 5 ° C.

Further, in the present invention, HDPE, LLDPE and VLDPE used as the polyethylene material are defined as follows. That is, HDPE has a density of 0.9
42 g / cm ³ or more, LLDPE has a density of 0.910
and g / cm ³ or more 0.942g / cm less than ^3, VLDP
E has a density of less than 0.910 g / cm ³ .

Further, the bending rigidity G _{2 of the} coating is G ₂ ≤12.
In the case of 0 [N · m ² ], the thickness of the metal foil forming the inner layer is preferably 150 μm, the pitch when the bellows-like corrugation is applied to the inner layer is preferably 2 mm, and the height difference between the mountains and the valleys is 0.5 mm is preferable.

[Operation] According to the configuration of the present invention, it is possible to bend the entire cable with a relatively small radius of curvature, for example, a bending diameter of 1000 mm or less, while having sufficient optical fiber core wire holding strength.

High density polyethylene material (HDPE)
When the spacer is formed by including the outer layer and the inner layer of the foamed resin material, the inner layer has low bending rigidity, and the outer layer has high bending rigidity and high strength. This makes it possible to achieve both the strength required to hold the optical fiber core wire and the bendability required to improve workability.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view of a multi-fiber optical fiber cable according to a first embodiment of the present invention, and FIG. 2 is a vertical sectional front view thereof. The basic configuration of this multi-core optical fiber cable is the same as that of the conventional multi-core optical fiber cable. That is, the spacer with spiral groove 1 ₁
A plurality of tape-shaped optical fiber cores (tape cores) 3 are laminated and held in the spiral grooves 2 formed on the outer periphery of the tape. The center of the spacer 1 ₁ is inserted through the tension member 4 made of steel stranded wire or steel wire. Holding spacer with spiral groove 1 ₁ Wrapping tape 5 and coating 6 ₁
Covered with.

Next, the characteristic structure of the first embodiment will be described. The spacer with spiral groove 1 ₁ has a two-layer structure in which an outer layer 1A ₁ provided with a plurality of spiral grooves 2 at an equal pitch on the outer periphery and an inner layer 1B ₁ having a tension member 4 inserted and held in the center thereof are coaxially arranged. There is. The outer layer 1A ₁ is made of a high density polyethylene material (HDPE). The inner layer 1B ₁ is formed of a foamed resin material, here, for example, a foamed polyethylene material.

The coating ₆₁ includes an outer layer 6A ₁ consisting of linear low density polyethylene material of solid (LLDPE), and an inner layer 6B ₁ comprising an aluminum foil of a metal foil and an example is constructed by coaxially disposed . In the coating 6 _{1 including the} outer layer 6A ₁ and the inner layer 6B ₁ , the inner layer 6B ₁ is corrugated.

Here, the bending rigidity of the member is the Young's
It can be expressed as the product of the modulus E and the moment of inertia of area I.
Wear. As shown in Fig. 3, the cable bending characteristics are measured.
The load on the center point of the sample cable supported across the fulcrum.
It is performed by measuring the amount of displacement when the weight P is applied. Center point
Load is P [N], sample support interval is L [m], displacement is v [m]
Then, the bending stiffness E · I [N · m²] Is represented by the following formula
It E ・ I = (P ・ L³) / 48v In this embodiment, high density polyethylene material (HDPE)
Outer layer 1A consisting of₁And insert the tension member 4 in the center.
Inner layer 1B made of expanded polyethylene material₁And to
Therefore spacer 1₁Are configured. In addition, linear low density
Layer 6A made of polyethylene (LLDPE)₁When
Inner layer 6B made of metal foil₁With inner layer 6B ₁Bellows
Attach and cover 6₁Are configured.

As a result, the outer diameter of the cable is 25 to 30 m.
When measured using a multi-fiber optical fiber cable having m and the number of cores of 400 to 1000 as an example, L = 0.5 m, v =
When 0.01 m, a flexural rigidity G ₁ of the spacer 1 ₁ coated 6
₁ the bending stiffness G _{2 is, G 1 ≦ 9.0 [N ·} m 2], G 2 ≦ 1
It becomes 2.0 [N · m ² ] (measurement at a temperature of 20 ± 5 ° C.). Therefore, the bending rigidity G _{0 of the} entire cable is G ₀ ≦ 2
It becomes 1.0 [N · m ² ] (measurement at a temperature of 20 ± 5 ° C.).

Therefore, it is possible to work with a bending diameter of 1000 mm or less for a multi-fiber optical fiber cable. Furthermore, in the present embodiment, the inner layer 1B ₁ in spacer 1 ₁
In the outer layer 1A ₁ , the bending rigidity is small, and in the outer layer 1A ₁ , the bending rigidity is large and the strength is high. This makes it possible to achieve both the strength required to hold the optical fiber core wire and the bendability required to improve workability.

The flexural rigidity G ₂ of the coating 6 ₁ is G ₂ ≦ 12.0
In order to obtain [N · m ² ], the molding conditions for the coating 6 ₁ are set as follows. That is, the thickness of the inner layer 6B ₁ (metal foil) made of metal foil, which is an example of aluminum foil, is 1
It is set to 50 μm. The pitch when the bellows-like corrugated treatment is applied to the inner layer 6B ₁ is 2 mm. Furthermore, the inner layer 6B
The height difference of the mountains and valleys when applying the bellows-like treatment to ₁ is 0.5
mm.

Next, a second embodiment of the present invention will be described. The configuration of the second embodiment is basically the same as in FIGS.
The same as the first embodiment described with reference to FIG. That is, each of the plurality of spiral grooves 2 formed on the outer peripheral of the spiral grooved spacer 1 _2, are engaged entering holding a tape-like coated optical fiber (the ribbon) 3 plurality of increments lamination. The center of the spacer 1 ₂ extends through the tension member 4 made of steel stranded wire or steel wire. This spiral grooved spacer 12 is covered with a press-winding tape 5 and a coating 6 ₂ .

Next, the characteristic structure of the second embodiment will be described. The spacer with spiral groove 1 ₂ has a two-layer structure in which an outer layer 1A ₂ having a plurality of spiral grooves 2 at an equal pitch on the outer periphery and an inner layer 1B ₂ having a tension member 4 inserted and held in the center thereof are coaxially arranged. There is. The outer layer 1A ₂ is formed of a linear low density polyethylene material (LLDPE). The inner layer 1B ₂ is formed of a linear low density polyethylene material (LLDPE) or an ultra low density polyethylene material (VLDPE).

The coating 6 _2, an outer layer 6A ₂ consisting of linear low density polyethylene material of solid (LLDPE), and an inner layer 6B ₂ made of aluminum foil of a metal foil and an example is constructed by coaxially disposed . Coating 6 ₂ with an outer layer 6A ₂ and the inner layer 6B ₂ is a bellows corrugation is applied to the inner layer 6B _2.

The bending rigidity, which can be expressed as the product of the Young's modulus E of the material and the moment of inertia of area I, is expressed by the following equation, as described above. E · I = (P · L ³ ) / 48v P [N]: center point load in FIG. 3, L [m]: sample support interval, v [m]: displacement amount In the present embodiment, linear low Density polyethylene material (LL
The spacer 1 ₂ is composed of an outer layer 1A _{2 made of} DPE) and an inner layer 1B ₂ made of a linear low density polyethylene material or a very low density polyethylene material (VLDPE) having a tension member 4 inserted and held in the center thereof. Further, an outer layer 6A ₂ made of a linear low density polyethylene material (LLDPE) and an inner layer 6B _{2 made of a} metal foil are provided, and the inner layer 6B ₂ is corrugated to form a coating 6 ₂ .

As a result, the outer diameter of the cable is 25 to 30 m.
m, a multi-core optical fiber cable having a number of cores of 400 to 1000 was measured as an example. L = 0.5 m, v = 0.
When 01M, and the flexural rigidity G ₂ flexural rigidity G ₁ and the coating 6 ₂ spiral grooved spacer _{1 2, G 1 ≦ 6.0 [} N · m 2], G
₂ ≤ 12.0 [Nm ² ] (measurement at temperature 20 ± 5 ° C)
become. Therefore, the bending rigidity G _{0 of the} entire cable is G ₀
≦ 18.0 [N · m ² ].

The flexural rigidity G ₂ of the coating 6 ₂ is G ₂ ≦ 12.0
In order to set [N · m ² ], the molding conditions for the coating 6 ₂ are set as follows, as in the first embodiment. That is, the inner layer 6B using aluminum foil as the metal foil
The thickness of ₂ (metal foil) is 150 μm. Inner layer 6
The pitch when the bellows-like corrugated treatment is applied to B ₂ is 2 mm. Further, the height difference between the peaks and valleys when the bellows-like corrugated treatment is applied to the inner layer 6B ₂ is 0.5 mm.

Therefore, work with a bending diameter of 1000 mm or less is possible for a multi-fiber optical fiber cable.

[0029]

As is apparent from the above description, according to the present invention, it is possible to improve the bending characteristics as a whole even in a large-diameter optical fiber cable that holds a large number of optical fiber core wires, and in a narrow field. It is possible to improve the handling property and the workability in.

[Brief description of drawings]

FIG. 1 is a perspective view of an optical fiber cable according to the present invention.

FIG. 2 is a vertical sectional front view of an optical fiber cable.

FIG. 3 is a principle diagram showing a method for measuring bending rigidity of a cable.

FIG. 4 is a perspective view of a conventional optical fiber cable.

[Explanation of symbols]

1 ₁ , 1 ₂ Spacer with spiral groove 1A ₁ , 1A ₂ Outer layer 1B ₁ , 1B ₂ Inner layer 2 Spiral groove 3 Optical fiber core wire 4 Tension member 5 Holding tape 6 ₁ , 6 ₂ Coating 6A ₁ , 6A ₂ Outer layer 6B ₁ , 6B ₂ Inner layer E · I Bending rigidity E Young's modulus of material I Second moment of area G ₁ Bending rigidity of spacer with spiral groove G ₂ Bending rigidity of coating G ₀ Bending rigidity of entire cable

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Ryo Nishikawa             4-3 Ikejiri, Itami City, Hyogo Prefecture Mitsubishi Electric Cable             Industrial Co., Ltd. Itami Works F term (reference) 2H001 BB09 BB16 DD04 DD24 KK06                       KK12 KK17 KK24 PP01

Claims (2)

[Claims] 1. A spacer having a tension member inserted through the center thereof and a groove extending substantially axially on the outer periphery of the tension member. The optical fiber core wire is inserted and held in the groove, and the spacer is attached. A multi-core optical fiber cable covered with a coating, wherein the spacer is an outer layer made of a solid high-density polyethylene material (HDPE) having the groove on the outer periphery, and a foamed resin in which the tension member is inserted and held in the center. Bending rigidity of this spacer G ₁
Is set to G ₁ ≦ 9.0 [N · m ² ], and the coating is a solid linear low-density polyethylene material (LL
DPE) and an inner layer composed of a metal foil, and the inner layer is corrugated,
The bending rigidity G ₂ of this coating is set to G ₂ ≦ 12.0 [N · m ² ], and the bending rigidity G _{0 of the} entire cable is set to G ₀ ≦ 21.0 [N · m ² ] (G ₁ , G ₂ and G ₀ are measured values at a temperature of 20 ± 5 ° C.), A multi-fiber optical fiber cable. 2. A spacer having a tension member inserted through the center thereof and a groove extending substantially axially on the outer periphery of the tension member. The optical fiber core wire is inserted and held in the groove, and the spacer is attached. A multi-core optical fiber cable covered with a coating, wherein the spacer is an outer layer made of solid linear low-density polyethylene material (LLDPE) having a plurality of the grooves on the outer circumference, and the tension member is provided at the center. Bending rigidity G of this spacer is obtained by constructing the inner layer made of a solid linear low-density polyethylene material (LLDPE) or a solid ultra-low density polyethylene material (VLDPE) which is inserted and retained.
₁ is G ₁ ≦ 6.0 [N · m ² ], and the coating is a solid linear low-density polyethylene material (LL
DPE) as an outer layer and an inner layer as a metal foil, and the inner layer is subjected to a corrugated corrugation so that the bending rigidity G ₂ of this coating is G ₂ ≦ 12.0 [N · m ² ]. The bending rigidity G _{0 of the} entire cable is set to G ₀ ≦ 18.0 [N · m ² ] (measured values at a temperature of 20 ± 5 ° C. for all G ₁ , G ₂ and G ₀ ), Multi-core optical fiber cable.