JPS62238508A - Optical fiber cable for underwater equipment - Google Patents

Abstract

PURPOSE:To improve the torsion resisting characteristic by constituting plural optical fiber cords formed by providing successively a tensile strength layer, a buffer layer and a reinforcing layer, on the periphery of an optical fiber core wire, and scattering them near the outside of a cable. CONSTITUTION:The titled cable is constituted so that with respect to each of plural pieces of optical fiber core wires 11, for instance, a tensile strength layer 12 consisting of an aramide fiber, etc., a reinforcing layer 14 by a hard plastic, etc., and a buffer layer 13 by a soft plastic, etc., and a reinforced optical fiber cord 15 is scattered and collected in the vicinity of the outside periphery of the cable. In this way, the resistance against a tension and a compression becomes high, and also, these optical fiber core wires 11 are constituted so as to be placed in the outside peripheral side by moving from the center of the cable, a tightening force from the outside is eliminated, and a fault caused by a torsion of the cable can be reduced.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention provides power supply, The present invention also relates to an optical fiber cable for underwater equipment suitable for supplying control signals.

[Summary of the invention]

Optical fiber cables for underwater equipment with unreleased IJ1 are usually
The optical fiber cores gathered in the center of the cable are scattered around the periphery of the cable to reduce the tensile stress or compressive stress that is applied to the optical fiber cores even when the optical fiber cable is twisted. It is designed to reduce the

Therefore, it is possible to prevent an increase in transmission loss or a disconnection accident due to cable twisting or the like.

[Conventional technology]

Cables that supply power and control signals to underwater robots, etc. are used with a mixture of optical fibers for communication and power lines for power supply, and these are made of suitable tensile strength wires,
It is configured to be insulated and reinforced by a sheath or the like.

FIG. 3 shows an example of such a conventional optical fiber cable, in which a central tensile strength member l made of wire rope or the like is arranged in the center, and a plurality of optical fiber cores 2 are arranged in a spiral around the central tensile strength member l. wrapped in a shape. After forming the buffer layer 3 with a suitable inclusion or elastomer, the outer periphery of the buffer layer 3 is covered with a sheath 4 made of plastic or the like to form an optical fiber unit 5.

A plurality of insulated power supply wires 6 are wound around the optical fiber unit 5 at a constant pitch, and a tensile strength member 7 made of multilayer winding of 7-laminated fibers is applied to the outer periphery, and sheathed with thermoplastic elastomer or the like. 8 to form an optical fiber cable.

[Problem that the invention seeks to solve]

By the way, when an optical fiber cable having a double-stranded structure is connected to an underwater robot or the like, twisting force is applied due to the movement of the underwater robot. Then, the optical fiber core 2 placed in the center receives a tightening force from the power supply insulated wire 6 and the tensile strength member 7, and the optical fiber core &
Tensile stress or compressive stress is applied due to the change in the twist pitch of li2, which increases the transmission loss of the optical fiber and, in extreme cases, may cause a disconnection accident.

That is, as shown in FIG. 4(a), the optical fiber core 2, which is wound around the central tensile strength member l with a twist pitch Po and a core diameter Do, is twisted twice within the length range. In the case of P+ = 2/3 Po, and if the layer core diameter does not change, standing co=:3r
The result is 7 pieces of paper, 7 pieces of paper, and 2 pieces.

Therefore, the elongation rate of the core wire E = s CO - s CO / j
L'co<1, and tensile stress will be applied.

Also, if the twist acts in the opposite direction to the twisting direction, EJI > 1
Therefore, it will be subjected to compressive stress.

Furthermore, due to such twisting, the optical fiber core wire 2,
Alternatively, the layer core diameter of the power feeding insulated wire 6 is also subjected to stress in the direction of expansion or contraction.

In this case, as shown in FIG. 5(a), for example, when a torsional stress is applied that reduces the layer core diameter of the power feeding insulated wire 6 on the outer periphery, the twisting direction of the power feeding wire 6 is opposite to that of the power feeding wire 6. Since the core diameter of the optical fiber core 2 twisted in this direction is subjected to stress in the direction of expansion, the intersection of the optical fiber core 2 and the insulated wire 6 is marked with an arrow in FIG. 5(b). As shown, there is a problem in that a large pressing force is applied through the sheath 4, causing microbending of the optical fiber core 2.

Conventional optical fiber cables have the disadvantage that, as mentioned above, when the cable is twisted many times, various stresses act on the optical fiber core 2, increasing transmission loss and causing disconnection due to microbending. was there.

The present invention has been made to eliminate such drawbacks, and provides an optical fiber cable for underwater equipment that has a high degree of torsional resistance.

[Means for solving problems]

That is, the optical fiber cable for underwater equipment of the present invention is
For example, a tensile strength layer made of aramid fiber, a reinforcing layer made of hard plastic, and a buffer layer made of soft plastic are applied to each of the plurality of optical fibers, and the reinforced optical fiber cord is connected to the cable. They are scattered and gathered near the outer periphery of the area.

[Effect]

Each optical fiber core is reinforced and protected by a tensile strength layer, a buffer layer, and a reinforcing layer, making it highly resistant to tension and compression. Since the cable is configured to be arranged in such a manner that stress is released when tightening from the outside, it is possible to reduce problems caused by twisting of the cable.

〔Example〕

FIG. 1 shows a cross-sectional structure of an optical fiber cable for underwater equipment according to an embodiment of the present invention, in which, for example, two insulated power supply wires 16A and an inclusion 19 are present together with a filler 20 in the central part. A four-layer tensile strength member 17 made of, for example, aramid fibers (Kevlar) is placed longitudinally on the outer periphery of the cable to bear the tensile strength of the cable.

On the outside of the tensile strength body 17, there is an optical fiber cord 15 which has been reinforced and protected as described later, along with an insulated power supply wire 16B.
are spirally wound at a fixed pitch by a predetermined number,
The gap is filled with a suitable inclusion.

A sheath 18 made of thermoplastic elastomer or the like is provided further outside.

FIG. 2 shows an enlarged cross-sectional view of the optical fiber cord 15. A tensile strength layer 12 made of aramid fiber or the like is vertically formed around the optical fiber core 11, and a soft PvC cushioning layer 12 is formed on this layer. The buffer layer 13 is made of plastic having the following properties. Furthermore, a reinforcing layer 14 made of polyamide-based hard plastic is provided on the outer periphery of the reinforcing layer 14.
is formed into an optical fiber cord 15.

Since the optical fiber cable for underwater equipment of the present invention has the above-described structure, even when the cable is twisted, the tensile stress applied to the optical fiber core 11 is absorbed by the buffer layer 13, and the optical fiber When compressive stress is applied to the core wire 11, the tonality of the optical fiber cord 5 is set high by the reinforcing layer 14, so that microbending can be prevented.

Furthermore, since the optical fiber cords 15 are scattered around the outer periphery of the cable, there is almost no tightening force from the outer periphery, which is caused by twisting, etc., and even if compressive stress is applied, the optical fiber cords 15 There is an advantage that it becomes easy to diverge in a direction perpendicular to the length direction of the fiber cord 15 (particularly in the direction of the sheath 18).

FIG. 6 shows that an optical fiber cord having the structure of the embodiment of the present invention described above and a conventional optical fiber cable are twisted, and the change in transmission loss (dB) is plotted on the vertical axis, and the number of twists is plotted. The data is plotted on the horizontal axis.

The twist was set to 3600 degrees per meter, and the twist direction was changed to rotate clockwise and counterclockwise every other turn.

As can be easily understood from this data diagram, in conventional optical fiber cables, the transmission loss increases rapidly with each twist as shown by the dotted line, and the cable breaks at about 10 twists.
In the case of the optical fiber cable of the present invention, as shown by the solid line, the transmission loss hardly changes even when twisted several tens to hundreds of times (not shown), and there is almost no mechanical failure. Remarkable effects are seen.

〔Effect of the invention〕

As explained above, in the optical fiber cable for underwater equipment of the present invention, the optical fiber core is processed into optical fiber cords, and these are scattered on the outside of the cable, so that the torsion resistance characteristics are significantly improved. This has the effect of causing a person to become depressed.

Therefore, there is an advantage that even when used in a machine that moves rapidly, such as an underwater robot, there is almost no transmission failure, making it possible to carry out more advanced exploration activities, observation work, etc.

Furthermore, since each optical fiber cord is coated with a reinforcing coating, it is possible to directly connect these to an optical fiber connector or the like after terminal processing, which has the advantage of simplifying the connection work.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing an embodiment of the optical fiber cable for underwater equipment of the present invention, Fig. 2 is an enlarged sectional view of an optical fiber cord, Fig. 3 is a sectional view of a conventional optical fiber cable, and Fig. 4. (a) and (b) are explanatory diagrams showing the elongation rate of the optical fiber when twisting is applied, and Fig. 5 (a) and (b) are explanatory diagrams showing the application of lateral pressure due to changes in the core diameter. FIG. 6 is a data diagram showing characteristic changes due to twisting of the optical fiber cable of the present invention and the conventional optical fiber cable. In the figure, 11 is an optical fiber core, 12 is a tensile strength layer, 13 is a buffer layer, 14 is a reinforcing layer, 15 is an optical fiber cord, 16
A and 16B are insulated power supply wires, 17 is a tensile strength member, and 18 is a plastic source. Figure 1 Figure 2

Claims (1)

[Claims] Insulated power supply wires, etc. are placed in the center, and the outer periphery is reinforced with a tensile strength material, and multiple optical fiber cords are sequentially coated with a tensile strength layer, a buffer layer, and a reinforcing layer around the optical fiber core. An optical fiber cable for underwater equipment, characterized in that the tensile strength body is spirally wound together with other insulated wires for power supply at a predetermined pitch on the outer surface of the tensile strength body, and the outermost side is coated with a plastic source.