JP3277222B2 - Optical fiber coil support structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a support structure for an optical fiber coil used in an optical fiber gyro.

[0002]

2. Description of the Related Art First, the construction of an optical fiber gyro is shown in FIG.
This will be described with reference to FIG. The light emitted from the light source 1 is sent through the optical directional coupler 2, the polarizer 3, and the optical directional coupler 4 into the optical fiber coil 5 constituting the sensing coil as clockwise light and counterclockwise light. The clockwise light is first phase-modulated by the phase modulator 6, and the phase-modulated clockwise light reaches the light receiver 7 via the optical directional coupler 4, the polarizer 3, and the optical directional coupler 2. . Similarly, the left-handed light is similarly phase-modulated in the phase modulator 6, and the phase-modulated left-handed light reaches the light receiver 7 via the light directional coupler 4, the polarizer 3, and the light directional coupler 2. I do.

The light that has reached the light receiver 7 is photoelectrically converted into an electric signal, and the converted electric signal is input to a synchronous detector 8. In the synchronous detector 8, a fundamental wave component which is an angular velocity output proportional to the rotational angular velocity about the central axis of the optical fiber coil 5 can be obtained using the signal supplied from the oscillator 9 as a reference signal. Next, a conventional optical fiber coil support structure will be described with reference to FIG. Optical fiber 2
1 is wound around a cylindrical core 23 and flanges 24 provided at both ends thereof.
A ring-shaped mounting portion 25 is formed integrally and protruding at the substantially central portion in the axial direction on the inner peripheral side.

[0004] A support base 26 is inserted into the winding core 23 of the winding frame 22, and a mounting portion 25 is mounted and fixed to the support base 26. The support 26 has a cylindrical shape and a base 27.
The insertion end, that is, the ring-shaped end surface 28 is in contact with the mounting portion 25. The attachment portion 25 is attached to the support 26 by screwing, that is, a screw 31 is screwed into a screw hole 32 formed in the end surface 28 of the support 26 through a hole 29 formed in the attachment 25. Fixed.

[0005]

Incidentally, the refractive index of the optical fiber coil 5 changes with temperature, and the stress state also changes due to expansion and contraction due to the temperature change, so that its characteristics change with temperature. Therefore, the performance of the optical fiber gyro is affected by the ambient temperature, and the change in the characteristics of the optical fiber coil 5 due to the temperature change includes an error in the angular velocity output, resulting in performance degradation.

For this reason, in the conventional optical fiber coil support structure shown in FIG. 4, since the main heat transfer due to the change in the ambient temperature is performed through the base 27, the support 26 is made of a low heat conductive material. , The heat conduction from the base 27 to the reel 22 was suppressed. On the other hand, in the optical fiber gyro, the temperature of the optical fiber coil 5 is monitored and the angular velocity output is corrected.

FIG. 5 shows a model of the above-mentioned conventional optical fiber coil support structure, and measures the temperature change of each part.
It is a graph. The schematic diagram of the support structure and the measurement points are shown in the figure. From FIG. 5, although the effect of delaying the heat conduction to the bobbin 22 is recognized, in this structure, there is a difference in the rate of temperature change between the points A, B, and C, that is, the bobbin 2
There is a difference in the rate of temperature change in the axial direction 2 and the heat is unevenly distributed, so that a uniform temperature distribution state of the optical fiber coil 5 cannot be obtained, and the temperature correction accuracy of the angular velocity output in the optical fiber gyro. And sufficient performance cannot be obtained.

On the other hand, FIG. 6 shows a temperature change state of a model of the supporting structure which is considered to balance the heat distribution in consideration of the non-uniformity of the heat distribution of the winding frame 22 in the conventional optical fiber coil supporting structure. It is shown. In this example, as in the prior art, the upper portion of the bobbin 22 is supported by a support 26 made of a low heat conductive material.
The position of No. 5 has been changed.

FIG. 6 shows that although the difference in the rate of temperature change at points A, B, and C is smaller than that in FIG. 5, there is still a difference that cannot be ignored. This is because the reel 22 and the support 26 are close to each other, and
2 and the support 26 is made of a low heat conductive material, so that the support 26 itself has a large thermal gradient as it moves away from the base 27, heat radiation is generated along the thermal gradient, and It is considered that the heat is transferred to the heat exchanger 22 while keeping the heat gradient.

The effect of the heat radiation is, for example, the
Can be eliminated by increasing the gap between the support 22 and the support 26. However, a small support structure is required in terms of space saving, and the gap between the winding frame 22 and the support 26 is increased in terms of structural strength. It is not preferable that the winding frame 22 and the support 2
6 is unavoidable and therefore the effect of this thermal radiation cannot be avoided.

FIG. 7 shows that the thermal gradient of the support 26 is reduced, and the position of the mounting portion 25 is the same as that of FIG. 6, and the temperature change state of the model of the support structure in which the support 26 is made of a high heat conductive material. It is shown. In this example, the thermal gradient generated as the distance from the support 26 to the base 27 becomes smaller, so that the distribution of heat transmitted from the support 26 to the reel 22 by heat radiation becomes substantially uniform, and points A, B, and C Very good results can be obtained in terms of the difference in the rate of change of the temperature.

However, in this example, since the absolute amount of heat transfer to the winding frame 22 is large and the temperature of the base 27 changes (change of ambient temperature), the temperature of the winding frame 22 changes suddenly. There is a possibility that the coil 5 may be thermally degraded.
SUMMARY OF THE INVENTION In view of these problems, the object of the present invention is that the winding form is hardly affected by the ambient temperature, that is, the temperature change amount and the temperature change rate of the winding form are small, and a uniform temperature distribution state of the winding form can be obtained. An object of the present invention is to provide an optical fiber coil support structure.

[0013]

According to the present invention, there is provided a cylindrical frame having a mounting portion projecting from the inner periphery of one end and a flange, and a winding frame on which an optical fiber is wound, and a base. A supporting table which is erected and inserted into the core, and whose insertion end is coupled to the mounting portion, wherein the winding frame and the inserting section of the supporting table into the core are each made of a high heat conductive material. Of the support,
The base reaching the insertion portion is made of a low heat conductive material.

[0014]

An embodiment of the present invention will be described with reference to FIG. Parts corresponding to those in FIG. 4 are denoted by the same reference numerals. In this example, in the axial direction of the cylindrical winding core 23, a ring-shaped mounting portion 25 is integrally formed on the inner periphery of the end opposite to the base 27, that is, the upper end side of the winding frame 22 is supported by the support 26. Structure. Core 2
3, the winding frame 22 composed of the flange 24 and the mounting portion 25 is made of a high heat conductive material, for example, Invar or the like is used as the material.

A cylindrical support 26 supporting the reel 22 around which the optical fiber 21 is wound is inserted into the core 23 and the inserted end thereof is connected to the mounting portion 25. An insertion portion 41 is located at a portion facing the inner peripheral surface, and a base 42 that reaches the insertion portion 41, that is, a base 42 that is located outside the bobbin 22, is stacked and supported on the base 27. 26 is erected.

The insertion portion 41 is made of a high heat conductive material such as an aluminum alloy, while the base 42 is made of a low heat conductive material. As the low thermal conductive material, for example, a resin material such as a polyetherimide resin is used.
The base 27 is made of an aluminum alloy or the like.
As shown in FIG. 1, the insertion portion 41 and the base portion 42 are each formed with a plurality of concave portions sequentially in the circumferential direction on both end surfaces thereof.
Both end surfaces are comb-shaped. In addition, both the insertion portion 41 and the base portion 42 are formed such that the concave portion on the upper end surface thereof corresponds to the position between the concave portions on the lower end surface, that is, the convex portion.
Further, each concave portion on the lower end surface of the insertion portion 41 is formed so as to face each concave portion on the upper end surface of the base portion 42.

An axially penetrating hole 43 is formed in each concave portion on the upper end surface of the base portion 42, while a screw hole 44 is formed in each convex portion. Similarly, the insertion portion 41 has a hole 45 penetrating in the axial direction in each concave portion on the upper end surface thereof, and a screw hole 46 formed in each convex portion. The assembly of the support structure is performed as follows. That is, the base 4
The screw 47 is screwed into the screw hole 48 of the base 27 through the second hole 43, and the base 42 is first attached to the base 27 and fixed. Next, the screw 49 is screwed into the screw hole 44 of the base 42 through the hole 45 of the insertion portion 41, the insertion portion 41 is attached to the base 42, and the support base 26 is assembled. Then, the screw 31 is screwed into the screw hole 46 of the insertion portion 41 through the hole 29 formed in the attachment portion 25 of the winding frame 22, and the attachment portion 25 is fixed to the upper end surface of the insertion portion 41 in contact with the screw 31. Support 26
And the assembling is completed. In this example, six screws 31, 47, and 49 are used for assembling, and one screw is shown in each drawing.

According to the above-described structure, the heat transfer from the base 27 to the insertion portion 41 is suppressed by the base 42 made of a low heat conductive material, so that the effect of delaying the heat transfer to the reel 22 can be obtained. , One side of the support 2 that is in close proximity to the bobbin 22
Since the insertion portion 41 is made of a high thermal conductive material, the heat gradient generated as the distance from the base 27 increases is extremely small, and the distribution of heat transmitted from the insertion portion 41 to the reel 22 by heat radiation is made substantially uniform. Can be. Therefore, the temperature change amount and the temperature change rate of the winding frame 22 due to the change in the ambient temperature can be reduced, and the temperature distribution can be made uniform.

FIG. 2 shows a model of the optical fiber coil support structure shown in FIG. 1 and, like FIGS.
The temperature change of each part is measured and graphed. From FIG. 2, it is understood that the temperature change rates of the respective portions (points A, B, and C) of the winding frame 22 are smaller than those in FIGS. 5 to 7, and that there is almost no difference between the temperature change rates of the points A, B, and C. . In the example described above, the base 42 and the insertion portion 41 are stacked and
However, for example, the diameter of the base portion 42 and the insertion portion 41 may be changed, and these portions may be overlapped in the radial direction at the joint portion and joined by screwing or the like.

[0020]

As described above, according to the present invention, the temperature change amount and the temperature change rate of the winding frame 22 due to the change in the ambient temperature can be made extremely small, and the temperature distribution can be made uniform. It can be. Therefore, if the optical fiber coil 5 of the optical fiber gyro is supported by this support structure, the performance of the optical fiber gyro can be prevented from deteriorating due to the influence of the ambient temperature, and an optical fiber gyro having good temperature characteristics can be obtained. it can. Since no rapid temperature change occurs in the winding frame 22, there is no possibility that the optical fiber coil 5 is thermally degraded.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing an embodiment of the present invention.

FIG. 2 is a graph showing a temperature change of each part measured using the model of the embodiment of the present invention.

FIG. 3 is a diagram illustrating a configuration of an optical fiber gyro.

FIG. 4 is an exploded perspective view showing a conventional optical fiber coil support structure.

FIG. 5 is a graph showing a temperature change of each portion measured using the model of the support structure shown in FIG.

6 is a graph showing a temperature change of each part measured using a model in which a supporting position is changed with respect to the supporting structure shown in FIG.

7 is a graph showing a temperature change of each part measured using a model in which constituent materials are changed with respect to the model of FIG. 6;

[Explanation of symbols]

 Reference Signs List 21 optical fiber 22 winding frame 23 winding core 24 flange 25 mounting part 26 support base 27 base 41 insertion part 42 base

Claims (1)

(57) [Claims] An optical fiber is wound around a cylindrical core having a mounting portion protruding from an inner periphery of one end thereof and a flange. And a support base, the insertion end of which is coupled to the mounting portion, wherein the insertion portions of the winding frame and the support base to the core are each made of a high heat conductive material, A support structure for an optical fiber coil, wherein a base portion of the stand reaching the insertion portion is made of a low heat conductive material.