JP2503790Y2 - Flexible non-metallic optical fiber cable - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION << Industrial Application Field >> The present invention relates to a highly flexible non-metallic optical fiber cable used in the field of optical communication.

<< Background of Invention >> Various types of optical fiber cables used for optical communication have been proposed in consideration of damage to the optical fiber itself due to compression of lateral pressure or the like.

A spacer having a plurality of spiral grooves for accommodating communication materials such as optical fiber ribbons on the outer circumference of the tensile strength wire is known as a typical structure of these, and this type of spacer is It is widely used because it can increase the number of cores of an optical fiber and has sufficient protection against lateral pressure.

In addition, in the spacer of this structure, from the viewpoint of non-electrical induction as an optical fiber cable, a non-metallic material for the tensile strength wire, for example, a fiber reinforced synthetic resin (FRP) linear material, or It is also known that a twisted wire is used from the viewpoint of flexibility, and the spiral groove is formed on the outer circumference thereof.

However, using a diameter derived from the cross-sectional area of the FRP linear material determined according to the tensile strength required for the cable, or an assumed diameter, a spiral groove is formed on the outer periphery by a thermoplastic resin. When the spacer is used, the rigidity of the entire spacer increases because it is integrally surrounded by a thick thermoplastic resin portion (a rib portion of the spacer or the like).

Therefore, the present inventors have completed the present invention by thoroughly studying the structure of an optical fiber cable that uses a FRP wire and has little resistance to bending, that is, has flexibility. The purpose of is to provide a non-metallic optical fiber cable having flexibility.

<< Means for Solving the Problems >> In order to achieve the above object, the invention of the present application is to provide a tensile strength member having a circular cross section arranged in the center, and a plurality of flat optical cords arranged on the outer periphery of the tensile strength material, A protective coating material that surrounds the outer periphery of the flat optical cord, wherein the tensile strength material is
The flat optical cord has a twisted structure made of a fiber-reinforced curable resin and a coating layer covering the outer periphery of the twisted structure, and the flat optical cord has a protective pipe provided with a space in the center and the space in the space. An optical communication material such as an optical fiber or a tape core wire to be inserted, and a tensile strength wire arranged on both sides of the space portion,
A plurality of them are arranged so as to circulate around the outer periphery of the tensile strength material, and are arranged spirally along the longitudinal direction of the tensile strength material.

The twisted structure composed of the fiber-reinforced curable resin that can be used in the present invention may have a structure in which at least the outer strands can independently undergo transitional behavior after the FRP linear objects that make up the twisted structure are cured. It is desirable from the viewpoint of flexibility, and as the twisted structure, a structure in which a plurality of outer peripheral strands are twisted in the same direction around a central core strand is preferable, such as 1 × 7 type.

A suitable twisted structure of this type and a method for producing the same are disclosed in the prior application of the present applicant (JP-A-2-259178) or (JP-A-3-51384).

The outer periphery of the twisted structure is required to be covered in a circular cross section because the protective pipes having a rectangular cross section will be arranged in a spiral shape later, and the tensile strength wire rod provided with such a protective covering material. In the above, it is desirable from the viewpoint of flexibility that the outer periphery of the twisted structure is not adhered to the protective covering material.

The protection pipe having a rectangular cross section used in combination with the present invention is disclosed by Japanese Patent Application Laid-Open No. 02-71207 filed by the applicant of the present invention, which is an optical fiber element wire or core wire or tape core wire. On the both sides of the space where the optical communication material is inserted, the coated tensile strength wire with the primary coating on the outer circumference of the FRP tensile strength wire is embedded on the outer circumference of the FRP tensile strength wire, and the main body is covered with a synthetic resin in a rectangular shape (protection pipe). It has been given.

After preparing a plurality of optical communication materials inserted into this protective pipe, arranging them in a spiral shape on the outer periphery of the tensile strength wire, and winding a cross tape made of polyester fiber or the like on the outer periphery, if necessary. An optical fiber cable is formed by protective coating with an appropriate thermoplastic resin.

Even in such a protective coating, it is desirable that the protective pipe having a rectangular cross section and the protective coating layer are not bonded to each other and can be freely displaced with respect to a force such as bending.

<< Effects >> The optical fiber cable of the present invention has a structure in which the FRP twisted structure, the protective covering material on the outer periphery of the FRP twisted structure, and the protective pipe with a rectangular cross section are not bonded to each other. Since each of these members can be individually displaced, the bending rigidity becomes small and the flexibility becomes high.

Further, since the tensile strength wires are arranged on both sides of the space through which the optical communication material is inserted, the protective pipe having a rectangular cross section can effectively protect the optical communication material against external force.

In the final optical cable with a protective coating,
The branching and extraction work from the cable can be handled with each optical communication material inserted in the protective pipe with a rectangular cross section, so the attention to the damage of the optical fiber can be reduced.

<< Embodiment >> A preferred embodiment of the present invention will be described below.

1 and 2 show an embodiment of a flexible non-metallic optical fiber cable according to the present invention.

The optical fiber cable shown in the figure has a tensile strength member 10 having a circular cross section, a plurality of flat optical cords 12 arranged on the outer periphery of the tensile strength member 10, and a protection surrounding the outer periphery of the flat optical cord 12. It is composed of a covering material 14.

The tensile strength material 10 includes a plurality of twisted structures 16 made of a fiber-reinforced curable resin, and a coating layer 18 covering the outer circumference of the twisted structures 16.
It consists of and.

As shown in FIG. 2 in detail, the flat optical cord 12 has a protection pipe 22 having a rectangular cross section with a rectangular space 20 in the center, and a light to be inserted into the space 20. It is composed of an optical communication material 24 such as a fiber or a fiber ribbon, and a pair of tensile strength wires 26 provided on both sides of the space 20.

The flat optical cord 12 configured in this manner, a plurality of the optical cords 12 are arranged on the outer periphery of the tensile strength material 10 so as to circulate the same, and are arranged spirally along the longitudinal direction of the tensile strength material 10. In this state, the protective coating material 14 is provided.

Next, a more specific example of the optical fiber cable having the above configuration will be described.

Example 1 A tensile strength wire 10 was manufactured by the following method.

First, an uncured vinyl ester resin (Mitsui Toatsu Chemicals: H-81 containing a peroxide catalyst in glass fiber roving).
00) impregnated and drawn to an outer diameter of 1.7 mm, then inserted into a crosshead die and coated with a molten linear low-density polyethylene resin (hereinafter referred to as LLDPE) in an annular shape with an outer diameter of 2.2 mm. The FRP twisted structure 16 with an apparent outer diameter of about 6.6 mm, which was twisted into a 1 × 7 type and cured at 100 ° C., is guided to a pressure die, covered with the LLDPE, and a tensile strength wire rod with an outer diameter of 7.5 mm 10
And

The glass fiber volume content of the FRP portion of this tensile strength wire 10 is 6
3%, the LLDPE coating does not adhere to the FRP interface or the interface with the twisted structure and does not adhere to each other, and the inhibition of flexibility by the thermoplastic resin is suppressed as much as possible.

On the other hand, the protection pipe 22 having a rectangular cross section and the flat optical cord 12 having the two-core tape core wire (optical communication material 24) inserted therein were manufactured by the following method.

First, as the tensile strength wire 26 of the protective pipe 22, after the aromatic polyamide fiber (Kevlar 49) is impregnated with the vinyl ester resin and draw-formed to an outer diameter of 0.65 mm, it is annularly coated with the LLDPE to an outer diameter of 0.8 mm. , Then cured at 140 ℃,
Further, the coating layer on the surface was shaped to have an outer diameter of 0.8 mm, and a Kevlar fiber volume content of 55% was used.

While supplying two of these tensile strength wires 26 at predetermined intervals,
A two-core optical fiber tape core wire (outside size 0.65 × 0.38 mm) is supplied, and a molten flame-retardant polyethylene resin is extruded from a pressure die to form a rectangular protective pipe 22 with a tensile strength wire 26 embedded therein. At the same time, the two-fiber optical fiber ribbon was inserted and wound on a drum.

At this time, the protective pipe 22 has a dimension and shape such that the space portion 20 for inserting the optical communication material is 1.0 × 1.0 mm, the distance between the tensile strength lines is 2 mm,
The external dimensions are 3.0 x 1.8 mm.

Nine flat optical cords 12 are prepared, and the outer diameter is 7.5mm.
On the outer circumference of the tensile strength wire 10, the spiral wire with a pitch of 150 mm is wound by rotating the tensile strength wire 10, and further, a non-woven fabric having a width of 50 mm and a thickness of 0.2 mm is twisted in the opposite direction to the twisting direction of the tensile strength wire. 2.6% by weight of carbon black with a draw-down type die
An optical cable was obtained by coating with the contained low-density polyethylene resin (protective coating material 14). This optical cable has a substantially nine-sided shape reflecting the state of the assembly of nine flat cords, and the outer diameter has an outer diameter of 14.7 to 15.5 mm and a coating thickness of 1.0 to 1.5 mm.

The obtained optical cable has a unit weight of 159 g / m, and the force (bending rigidity) required to bend a 1.25 m-long cable into 800 mm, 600 mm, and 400 mm diameters is 350 g, 450 g, and 950 g, respectively. The increase in transmission loss with respect to the compressive load on the cable is within the allowable range and can be sufficiently put into practical use.

Incidentally, as the spiral spacer having a number of accommodating core wires of 128, the tensile strength wire 10 of the embodiment of the present application was used, and a die groove having a groove width of 2.5 mm and a groove depth of 2.5 mm was formed on the outer periphery thereof with an outer diameter. The flexural rigidity of the 15.5 mm spacer was 4.6 kg for a 400 mm diameter, and the rigidity was extremely high.

As is clear from the above description of the specific implementation state, the optical fiber cable of the present invention is extremely flexible.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a flexible non-metallic optical fiber cable according to the present invention, and FIG. 2 is a sectional view of an optical cord used in the cable. 10 …… Tensile material 12 …… Optical cord 14 …… Protective coating material 16 …… Twisted structure 18 …… Coating layer 20 …… Space 22 …… Protection pipe 24 …… Optical communication material 26 …… Tensile wire

Claims (1)

(57) [Scope of utility model registration request] 1. A tensile strength material having a circular cross section arranged in the center, a plurality of flat optical cords arranged on the outer circumference of the tensile strength material, and a protective covering material surrounding the outer circumference of the flat optical cord. The tensile strength material has a twist structure made of a fiber-reinforced curable resin, and a coating layer that covers the outer periphery of the twist structure, and the flat optical cord has a space in the center. It has a protective pipe, an optical communication material such as an optical fiber core wire or a tape core wire that is inserted into the space, and tensile strength wires arranged on both sides of the space, a plurality of which are the outer periphery of the tensile strength material. A flexible non-metallic optical fiber cable, wherein the flexible non-metallic optical fiber cable is arranged so as to wrap around and is spirally arranged along the longitudinal direction of the tensile strength material.