JPH02238412A - Small-diameter optical cable - Google Patents

Abstract

PURPOSE:To facilitate the additional laying of a cable to meet an increase in demand by disposing a tension member at a center, providing optical fibers around this member, successively providing a UV curing resin packed layer for buffer and a thermoplastic resin jacket layer on these fibers so as to enclose the fibers and further providing a sheath for reinforcement, etc. CONSTITUTION:The tension member 1 is disposed at the center and the optical fibers 2 having the UV curing type coating are provided around this member. The UV curing resin packed layer 3 for buffer consisting of silicone acrylate, etc., is provided on these fibers to enclose the fibers and further, the thermoplastic jacket 4 consisting of nylon or the like is provided on the outer side thereof; further, a 'Kevlar(R)' layer 5 and the sheath 6 consisting of rubber or thermoplastic resin are provided. The effect of a mechanical protection is sufficient in this way and the formation of the smaller-diameter cable is possible.

Description

[Detailed Description of the Invention] <Industrial Application Field> This invention aims to increase the communication capacity of optical cables used as subscriber cables installed in offices where information is concentrated, such as intelligent buildings. .

<Conventional technology> When optical fiber cables were first introduced, they were introduced into long-distance relay systems.
Its use is gradually expanding to subscriber systems. In terms of subscribers, a lot of demand is expected for offices where information is concentrated, such as intelligent buildings, which are being developed at a rapid pace in recent years.

Since not only communication cables but also power cables, water supply and sewage cables, etc. are installed in such buildings, it is essential to reduce the diameter of communication cables.

By the way, in a conventional subscriber cable, for example, as shown in FIG. 4, a tension member 10 is provided at the center, a slot 1l is provided around the tension member 10, and a recess l is provided outside the slot l1.
A structure is known in which a 0.9 mm optical fiber core 13 is attached to a core 2 and a core wrap 14 and a jacket 15 are provided on the outside thereof.

<Problem to be solved by the invention> In such a conventional cable, the 8
Taking a core cable as an example, since the outer diameter of the cable is 9 mm, it is predicted that it will be difficult to install additional cables to meet future increases in demand due to space limitations.

This invention aims to solve such problems.

<Means for Solving the Problems> The outline of the present invention is to center around a tension member, provide an optical fiber having a thin ultraviolet curable coating around the tension member, and wrap the tension member to form an ultraviolet curable coating for buffering. This is a small-diameter optical cable characterized by sequentially providing a resin filling layer and a thermoplastic resin jacket layer, and further providing a reinforcing sheath and the like.

The reason why the covering material for the strands is limited to an ultraviolet curing type is that a thermosetting type has a weak mechanical strength, so that a thin layer cannot provide the desired strength. In addition, the filling layer was limited to UV-curing type because the covering material of the wire is UV-curable, which has poor heat resistance, and if you try to coat it with thermosetting resin, it will deteriorate due to the high curing temperature. It is from.

By doing this, it is possible to provide a strong optical cable using a thin wire as the optical fiber core wire and without using a slot to increase the outer diameter as in the conventional case.

Embodiment> As shown in FIG. 1, an embodiment of the present invention is centered around a tension member 1, and around the tension member 1 is provided an optical fiber 2 having an ultraviolet curable coating of, for example, 0.25 mm. A buffering ultraviolet curable resin filling layer 3 made of silicone acrylate or the like, and a thermoplastic resin jacket 4 such as nylon, polyethylene, FEP, Hytrel (a DuPont thermoplastic resin product name) on the outside.
The cable is further provided with a Kevlar layer 5 and a jacket 6 made of rubber or thermoplastic resin.

When using such a cable, since the optical fiber core wire 2 as thin as 0.25 mm is used, it is normally weak against external forces and suffers a lot of light loss, but by providing each strand with an ultraviolet curable resin filling layer 3 and The provision of the thermoplastic resin jacket 4 provides a cushioning effect against external forces and protects the optical fiber, thereby preventing an increase in optical fiber loss.

It should be noted that the Kevlar layer 5 and the jacket 6 made of rubber or thermoplastic resin naturally have a general protective function for the cable, and the tension member 1 is a tension wire to withstand the tension when the cable is laid. It is similar to

The outer diameter of the cable constructed in this manner is approximately 5 mm, and the cross-sectional area can be reduced to approximately 1/3 of that of conventional cables.

FIG. 2 shows another embodiment of the invention, in which the Kevlar layer 5. In place of the outer cover 6 made of rubber or thermoplastic resin: J7 ray
P(A l/PE)? , commata with rope wA8. The outer sheath 6 made of thermoplastic resin is sequentially provided, and since a steel wire 8 having a high Young's modulus is placed in the sheath as a sheath, the tensile strength can be further increased. Other curing procedures were the same as those shown in FIG. 1 above.

FIG. 3 shows yet another embodiment, which differs from FIG. 1 in that instead of the single ultraviolet curable resin filling layer 3, it is constructed with a soft filling layer 3A made of silicone acrylate and a hard filling layer 3B made of epoxy acrylate. This is what I did. This allows the cable to have even higher lateral pressure resistance.

<Effects of the Invention> According to the present invention, even though the thin optical fiber core wire is used as described above, the mechanical protection effect is sufficient and the diameter of the cable can be reduced.

[Brief explanation of drawings]

1 to 3 are cross-sectional views of an embodiment of the present invention, and FIG. 4 is a cross-sectional view of an example of a conventional cable. l; Tension member 2; Optical fiber 3; Ultraviolet curing resin filling layer

Claims (1)

[Claims] An optical fiber having a thin ultraviolet curable resin coating is provided around the tension member, and an ultraviolet curable resin filling layer and a thermoplastic resin jacket layer for buffering are sequentially provided around the tension member. A small-diameter optical cable characterized by having a reinforcing sheath, etc.