JPH01275377A - High speed reeling out light fibre reel - Google Patents

Abstract

PURPOSE:To arrange so that a winding collapse such as a crevice or the like which is caused by a temperature cycle may not occur at the winding around of light fibres wound around a bobbin, by forming this bobbin at a light fibre reel, out of a specified fibre reinforced plastic. CONSTITUTION:Light fibres 2 are wound around at a close pitch a tapered cylindrical bobbin 1 at a light fibre reel mounted at the rear portion of a missile or the like, and light fibres are pulled out at a high velocity of one end of the shaft direction of the bobbin as this missile flies and a data link between the missile and the ground is done through these light fibres 2. At this instance, the bobbin 1 is formed of fibre reinforced plastic whose fibre is arranged so that the rate of heat expansion in a perimeter direction may become smaller than the rate of heat expansion in a shaft direction. As a result, even in the case of being encountered with a temperature cycle due to the repetition of a high temperature and a low temperature, the occurrence of a large change at a side pressure acting upon the lower layer of light fibres 2 wound around the bobbin 1, can be prevented. As a result, a winding collapse does not occur at all the winding around of light fibres 2.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an optical fiber reel for high-speed feeding.

In particular, the present invention relates to an optical fiber reel that is mounted on the rear part of a flying object such as a missile, and is wound with an optical fiber that is sequentially unrolled as the flying object flies and provides a data link between the flying object and the ground. be.

[Prior art]

Conventionally, optical fiber reels mounted on flying objects for data links with the ground are wound with optical fibers wrapped around tapered bobbins at close pitches in order to smoothly unwind the optical fibers at high speed. Can be attached. and,
During this winding, a predetermined winding tension is applied to the optical fiber in order to prevent the optical fiber from collapsing during unwinding. Therefore, the bobbin needs to have strength and rigidity that can prevent deformation and buckling due to this winding tension and maintain the tightly wound pitch shape of the optical fiber. is made of aluminum alloy or magnesium alloy.

[Problem to be solved by the invention]

By the way, this type of optical fiber reel is placed in an environment where it repeatedly encounters high temperature and low temperature conditions during use or storage. Under such temperature cycles, the reel develops gaps or cracks in the optical fiber layer that extend radially inward from the outer periphery due to the difference in thermal expansion properties between the bobbin and the optical fiber wound on the bobbin. This causes the tightly wound shape to collapse and the winding tension to decrease.
This phenomenon occurs, making smooth high-speed feeding impossible. Furthermore, if the tightly wound shape is disrupted in this way, fatal problems such as disconnection or instantaneous increase in transmission loss may occur during the unwinding of the optical fiber.

Accordingly, an object of the present invention is to provide an optical fiber reel for high-speed feeding that does not cause cracks or other damage to the closely wound shape of the optical fiber layer due to temperature cycles encountered by the optical fiber reel.

[Means to solve the problem]

In order to solve the above problems, in the optical fiber reel according to the present invention, the bobbin is configured to have different thermal expansion characteristics in the axial direction and the radial direction. That is, the optical fiber reel according to the present invention includes a tapered cylindrical bobbin and an optical fiber wound around the bobbin at a close pitch, so that the optical fiber is pulled out at a high speed from one axial end of the bobbin. The bobbin is of the following format:
It is made of fiber-reinforced plastic with fibers arranged so that the coefficient of thermal expansion in the circumferential direction is smaller than the coefficient of thermal expansion in the axial direction.

[For production]

The causes of defects such as cracks in optical fiber windings due to significantly fluctuating temperature cycles are the longitudinal and radial thermal expansion coefficients of the optical fiber, and the thermal expansion coefficient of the bobbin material. This is thought to be due to the difference in In other words, the coefficient of thermal expansion in the longitudinal direction of the optical fiber is very small compared to the coefficient of thermal expansion in the radial direction, and the coefficient of thermal expansion of the material constituting the bobbin is equal to the coefficient of thermal expansion in the longitudinal direction of the optical fiber and the radial direction. The coefficient of thermal expansion is between the two directions. When the temperature rises during storage of the reel, thermal expansion in the longitudinal direction of the optical fiber acts to loosen the winding pressure of the optical fiber, and thermal expansion in the radial direction acts to strengthen the winding pressure. . The above-mentioned thermal expansion characteristics of the optical fiber act to increase the winding pressure as a whole when the temperature rises. In addition, the radial expansion of the bobbin acts to further increase the winding pressure. Therefore, at high temperatures,
In the lower layer of the optical fiber, the lateral pressure that tries to press the optical fiber against the bobbin increases, causing deformation of the coating of the optical fiber, and when the temperature is low, the lateral pressure decreases, creating a gap between the optical fibers. It turns out. If this operation is repeated, the optical fiber wound around the bobbin will no longer be able to maintain a close pitch, and the initial winding will change in space factor and become uneven, resulting in areas with low space factors. As a result, cracks as described above will occur in the optical fiber layer.

In the optical fiber reel of the present invention, as described above, the bobbin has different coefficients of thermal expansion in the axial direction and the radial direction, and in particular, the coefficient of thermal expansion in the circumferential direction is smaller than the coefficient of thermal expansion in the axial direction. Even if this occurs, changes in lateral pressure acting on the underlying optical fiber can be significantly suppressed. Therefore, cracks will not occur in the winding of the optical fiber even under temperature cycles caused by repeated high and low temperatures.

〔Example〕

FIG. 1 is a sectional view showing an example of an optical fiber reel for high-speed feeding to which the present invention is applied. The bobbin 1 has a tapered shape with a circular cross section, and an optical fiber 2 is arranged around the bobbin.
are wound with close pitch. A case 3 is placed outside the optical fiber 2 wound around the bobbin 1. Bobbin 1
The state in which the optical fiber 2 is wound above is shown in an enlarged cross section in FIG. In the optical fiber reel constructed in this way, the optical fiber 2 is let out in the direction shown by arrow A in FIG.

FIG. 3 shows the structure of the bobbin 1 in one embodiment of the present invention. In this example, the bobbin 1 is composed of a laminate of resin-impregnated carbon fibers. The carbon fibers are hoop-wound so as to extend in the circumferential direction of the bobbin 1 by a filament winding method. According to this configuration, the thermal expansion coefficient in the circumferential direction of the bobbin 1 can be extremely low, and the thermal expansion coefficient in the axial direction has a large value corresponding to the thermal expansion coefficient of the resin. By using a bobbin, thermal expansion in the radial direction of the bobbin 10 can be significantly suppressed, and changes in the lateral pressure acting on the lower layer of the optical fiber 2 can be suppressed.

FIG. 4 is a cross-sectional perspective view of a bobbin showing another embodiment of the present invention. In this example, the bobbin 1 is made of resin impregnated glass fibers formed on a cross-winding layer 4 and a core layer 4. It is composed of a hoop-wound layer 5 formed by filament winding of impregnated carbon fiber. glass ta
The cross-winding layer 4 of 'r& has a structure in which resin-impregnated glass fibers are wound in a cross shape.
By appropriately determining the thickness of the layer 5 and the thickness of the layer 5, it is possible to select a desired value for the ratio of the axial thermal expansion coefficient to the radial thermal expansion coefficient of the bobbin 1.

〔effect〕

As described above, in the present invention, the fibers are arranged in the bobbin constituting the optical fiber reel for high-speed feeding so that the coefficient of thermal expansion in the circumferential direction is smaller than the coefficient of thermal expansion in the axial direction! Since it is made of fiber-reinforced plastic, it can prevent large changes in the lateral pressure acting on the lower layer of the optical fiber wound around the bobbin even if it encounters temperature cycles caused by repeated high and low temperatures. This solves the conventional problem of cracks and other unwinding occurring in the winding of optical fibers wound at close pitches.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing an example of an optical fiber cooler to which the present invention can be applied, FIG. 2 is an enlarged cross-sectional view showing how the optical fiber is wound around a bobbin, and FIG. FIG. 4 is a perspective view of a bobbin according to one embodiment. FIG. 4 is a perspective view showing a part of a bobbin according to another embodiment. 1...Bobbin, 2...Optical fiber, 3...
Case Figure 1 Figure 2 Figure 6 Figure 4

Claims (3)

[Claims] (1) An optical fiber reel consisting of a tapered cylindrical bobbin and an optical fiber wound around the bobbin at a close pitch, the optical fiber being pulled out at high speed from one axial end of the bobbin, The optical fiber reel is characterized in that the bobbin is made of fiber-reinforced plastic in which fibers are arranged so that the coefficient of thermal expansion in the circumferential direction is smaller than the coefficient of thermal expansion in the axial direction. (2) The optical fiber reel according to claim 1, wherein the bobbin is a fiber-reinforced plastic made of carbon fiber hoop-wound using a filament winding method. (3) The optical fiber reel according to claim 1, wherein the bobbin has a composite structure of cross-laminated glass fibers and hoop-wound carbon fibers by filament winding.