JP5275885B2 - Bobbin for optical fiber coil - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bobbin for an optical fiber coil which enables integration of three optical fiber coils disposed at right angles to each other and is excellent in dimensional accuracy and mechanical strength. <P>SOLUTION: The bobbin 10 consists of a cubic solid block and the outer surface 11 of the bobbin is composed of a pair of first plane parts 12 and 12, a pair of second plane parts 13 and 13 and a pair of third plane parts 14 and 14, which intersect each other at right angles. Three winding grooves 15, 16 and 17 for winding optical fibers around are formed in the outer surface 11. All of the three winding grooves 15, 16 and 17 are made open in the outer surface 11 and to circle the first plane parts 12 respectively in parallel, the second plane parts 13 and the third plane parts 14. The respective centers of the three winding grooves 15, 16 and 17 are made to agree with the central point C of the solid block and so circle them as to form round shapes having different radiuses from each other. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to an optical fiber coil bobbin used for an optical gyro (optical fiber gyro) that detects an angular velocity using an optical fiber, and more particularly, suitable for a multi-axis optical fiber gyro that detects a multi-axis angular velocity. The present invention relates to an optical fiber coil bobbin.

  Interferometric fiber optic gyro (a form of fiber optic gyro) that measures the angular velocity of a moving object from the phase change caused by the Sagnac effect on two lights that circulate in opposite directions in an optical fiber loop is an aircraft, rocket, etc. It has been put into practical use for a long time mainly in the field of (see, for example, Patent Document 1).

  In recent years, the demand for a three-axis optical fiber gyro that detects angular velocities in three orthogonal axes has increased, and there has been a demand for price reduction and size reduction. For example, the conventional multi-axis fiber gyro 50 shown in FIG. 7 is basically constructed by arranging three so-called phase modulation type interference type optical fiber gyros. Cost, weight, and volume are reduced by sharing or integrating the element 52 (see Patent Document 2).

  Patent Document 2 discloses a configuration in which a light source 53 is shared in addition to the phase modulator 51 and the light receiving element 52, but an optical fiber loop (optical fiber coil) 54 requiring a relatively large space is integrated. The configuration is not disclosed. A normal single-axis optical fiber loop is configured by winding an optical fiber around a cylindrical bobbin in a bobbin shape. Therefore, in a three-axis optical fiber gyro, generally, three bobbins wound with optical fibers are separately prepared by positioning or fixing members or jigs and arranged orthogonal to each other.

  On the other hand, a multi-axis type bobbin in which three bobbins are arranged concentrically and integrated has been proposed. FIG. 8 shows a triaxial bobbin 70 disclosed in Patent Document 3 as a configuration example of a conventional integrated multi-axis bobbin. The triaxial bobbin 70 is composed of three ring-shaped unit bobbins 71, 72, 73. On the outer peripheral side surfaces of the three unit bobbins 71, 72, 73, grooves for winding the optical fiber are formed along the circumferential direction. A unit bobbin 72 is combined in the unit bobbin 71 and a unit bobbin 73 is combined in the unit bobbin 72 so as to be orthogonal to each other, forming a hollow sphere as a whole.

JP-A-6-74775 JP 2008-309695 A JP-A 61-266911

  As described above, the three-axis bobbin 70 is integrated by concentrically arranging three ring-shaped bobbins orthogonal to each other, so that the bobbin can be downsized. However, since it is necessary to configure a combination of three types of unit bobbins having different diameters, the number of parts and assembly man-hours are large, and it is difficult to promote cost reduction. In addition, since the region of the portion where the unit bobbins are joined together is small, it is difficult to arrange the three types of unit bobbins orthogonally with high accuracy.

  Further, since the triaxial bobbin 70 is formed in a spherical shape as a whole, when it is attached to the triaxial optical fiber gyroscope, a positioning member or a fixing member or jig is separately required, and assembly of the apparatus is required. The process becomes complicated.

  Further, since the triaxial bobbin 70 is hollow and each of the unit bobbins 71, 72, 73 is formed in a beam shape having a relatively narrow width, the mechanical strength may be insufficient. When the mechanical strength is insufficient, an external force applied to the bobbin is transmitted to the optical fiber loop, and the phase of light propagating through the optical fiber is likely to change. For this reason, there is a concern that the measurement accuracy of the optical fiber gyroscope using the triaxial bobbin 70 is lowered.

  Therefore, the present invention has been made in view of such problems, and is a multi-axis type that has excellent mechanical strength and positional accuracy of a plurality of winding grooves while being easy to manufacture with a small number of parts. An object of the present invention is to provide an optical fiber coil bobbin used in an optical fiber gyro.

Therefore, in order to solve the above problems, a feature of the present invention is an optical fiber coil bobbin for use in an optical gyro for detecting the angular velocity of the moving object based on the Sagnac effect using optical fiber, perpendicular to each other 3 A pair of plane portions and a pair of plane portions that are orthogonal to each other for winding an optical fiber and each of two pairs of plane portions of the three pairs of plane portions, respectively, and the other pair of pair of plane portions. A solid block having three winding grooves that circulate parallel to the plane portion on the outer surface, and the bottom surface of at least one of the three winding grooves is another winding groove. It is divided by .

  Moreover, the preferable aspect of this invention is that the said block is a hexahedron.

In another preferred embodiment of the present invention, the winding areas of the winding grooves are equal to each other.
In another preferred embodiment of the present invention, each of the winding grooves has a circular shape with a circular shape having the same radius, and the rotation centers are deviated from each other.
In another preferred embodiment of the present invention, the three winding grooves are a first winding groove disposed near the center of the solid block, and a rotation center of the first winding groove. It consists of a second winding groove and a third winding groove that are arranged orthogonally to each other on the outside, and the second winding groove and the third winding groove are the same as the first winding groove. The distance from the center of rotation is different.

  According to this invention, since a winding groove for winding two or three optical fibers is formed in one solid block, the number of parts and assembly compared with a conventional multi-axis bobbin Man-hours can be reduced. Moreover, since the bobbin is comprised from the solid block, it is excellent in mechanical strength. In addition, since the bobbin has at least one flat part, the bobbin can be stably mounted on the optical fiber gyro with the flat part as a mounting surface. Furthermore, it is possible to form the winding groove with high accuracy by using the plane portion as a processing reference surface.

1 is a perspective view showing an overall configuration of an optical fiber coil bobbin according to an embodiment of the present invention. It is YZ sectional drawing which shows the state which wound the optical fiber around the bobbin for optical fiber coils. It is XZ sectional drawing which shows the state which wound the optical fiber around the bobbin for optical fiber coils. It is XY sectional drawing which shows the state which wound the optical fiber around the bobbin for optical fiber coils. It is a conceptual diagram for demonstrating the semiconductor ring laser gyro using an optical fiber. It is the bobbin for optical fiber coils which concerns on other embodiment of this invention, (a) is a perspective view which shows the whole structure, (b) is XZ sectional drawing. It is a block diagram which shows the conventional multi-axis type optical fiber gyro. It is an external view which shows the conventional 3-axis bobbin.

  Hereinafter, a bobbin 10 will be described as an example of a preferred embodiment of an optical fiber coil bobbin according to the present invention with reference to the drawings. In describing the configuration of the bobbin 10, as shown in FIG. 1, an XYZ coordinate system including an X axis, a Y axis, and a Z axis orthogonal to each other is assumed.

  As shown in the figure, the bobbin 10 is formed from a solid block (a regular hexahedron) solid block (in this embodiment, an aluminum block) as a whole. That is, the outer surface 11 of the bobbin 10 is composed of six flat portions 12 to 14 having the same shape, which are square as a whole. More specifically, the outer surface 11 includes a pair of first plane parts 12 perpendicular to the X axis, a pair of second plane parts 13 perpendicular to the Y axis, and a pair of third plane parts perpendicular to the Z axis. 14. And three pairs of plane parts 12-14 are mutually orthogonally crossed.

  On the outer surface 11 of the bobbin 10 thus configured, three winding grooves 15, 16, and 17 (first winding groove 15, second winding groove 16, and third) for winding an optical fiber are provided. A winding groove 17) is formed. The three winding grooves 15, 16, and 17 are orthogonal to each other and are formed so as to go around two pairs of plane portions among the three pairs of plane portions 12 to 14. For this reason, each of the six flat portions 12 to 14 is actually divided into four by two of the three winding grooves 15, 16, and 17.

  Next, the three winding grooves 15, 16, and 17 will be described in detail with reference to FIGS. 2 to 4 are respectively parallel to the YZ plane (plane orthogonal to the X axis), the XZ plane (plane orthogonal to the Y axis), and the XY plane (plane orthogonal to the Z axis). FIG. 3 is a cross-sectional view passing through the center point C of the bobbin 10. 2 to 4, three optical fiber coils 18, 19, 20 (first optical fiber coil 18, second optical fiber coil 18, second optical fiber coil 18, 2) are formed by winding optical fibers along the bottom surfaces of the winding grooves 15, 16, 17. An optical fiber coil 19 and a third optical fiber coil 20) are schematically shown.

  First, as shown in FIG. 2, the first winding groove 15 circulates in parallel with the first flat surface portion 12 (YZ plane), and the circular shape is centered on the center point C of the bobbin 10. It is formed in a circular shape. The winding shape of the winding groove 15 is basically a shape in which the bottom surface (center) of the winding groove 15 surrounds, but the portion where the bottom surface is divided by the winding groove 17 is extrapolated. It is a shape (a shape assumed that the winding groove 17 does not exist). That is, the winding shape of the winding groove 15 is the winding shape of the optical fiber coil 18.

  Next, as shown in FIG. 3, the second winding groove 16 circulates in parallel with the second flat surface portion 13 (XZ plane), and the circular shape has a center point C of the bobbin 10. It is formed in a circular shape with a center. As shown in FIG. 4, the third winding groove 17 circulates in parallel with the third plane portion 14 (XY plane), and the circular shape is centered on the center point C of the bobbin 10. It is formed in a circular shape.

  That is, the three winding grooves 15, 16, and 17 are formed concentrically with the center point C of the bobbin 10 as the rotation center. Further, the three winding grooves 15, 16, and 17 are formed in a rectangular shape whose cross-sectional shape in the width direction opens the outer surface 11.

  Further, the three winding grooves 15, 16, and 17 have R1> R2> R3, where R1, R2, and R3 are the radiuses of the circular shape (the shortest distance between the center point C and the bottom surface of the winding groove), respectively. It is formed to be in a relationship.

  The difference (R1−R2) between the radius R1 of the first winding groove 15 and the radius R2 of the second winding groove 16 is at least a cross section of the second optical fiber coil 19 mounted in the second winding groove 16. It is set larger than the thickness. The difference (R2−R3) between the radius R2 of the second winding groove 16 and the radius R3 of the third winding groove 17 is at least a cross section of the third optical fiber coil 20 mounted in the third winding groove 17. It is set larger than the thickness. In short, the radii R1, R2, and R3 are respectively set in the three winding grooves 15, 16, and 17 so as to ensure a state in which there is no interference (contact) between the optical fiber coils 18, 19, and 20.

  Next, the superiority of the bobbin 10 configured as described above over the prior art will be described.

  Since the bobbin 10 is formed from one solid block, the work of assembling the three bobbins as in the prior art becomes unnecessary, and the manufacturing process can be simplified. Moreover, since the bobbin 10 is formed from the solid block, the robustness of the bobbin 10 as a whole can be improved. For this reason, transmission of the external force applied to the bobbin 10 to the optical fiber coil is suppressed. As a result, it can be expected that the measurement accuracy of the optical fiber gyroscope using the bobbin 10 is not affected by the external force and is stabilized.

  Moreover, since the bobbin 10 is formed in a cube as a whole and the outer surface 11 is composed of six plane portions 12 to 14, the bobbin 10 is used as a mounting surface for the bobbin 10 as a light. Can be stably mounted on fiber gyros. Thereby, the operation | work which attaches a bobbin to an optical fiber gyro becomes easy.

  Further, in the bobbin 10, each of the three winding grooves 15, 16, and 17 orthogonal to each other is formed in parallel to one of the three pairs of plane portions 12 to 14 constituting the outer surface 11 and orthogonal to each other. ing. For this reason, the three winding grooves 15, 16, and 17 are formed by, for example, cutting, using the three pairs of the plane portions 12 to 14 (or the three plane portions 12, 13, and 14) as the processing reference plane. be able to. Thereby, each winding groove | channel 15,16,17 can be mutually orthogonally arranged with a sufficient precision.

  Although an example of a preferred embodiment of the present invention has been described above, the embodiment is not limited to the above, and various modifications can be made without departing from the gist of the present invention.

  For example, although the entire shape of the bobbin 10 is a cube, it may be a rectangular parallelepiped (hexahedron) or a cylinder instead. In the case of a cylinder, the effect of a cube and a rectangular parallelepiped cannot be expected from the viewpoint of machining accuracy. However, by using a pair of plane parts (or one plane part) at both ends in the axial direction of the cylinder as a machining reference plane, it is possible to achieve a certain level. The effect can be expected. In short, a certain effect can be expected if the bobbin is formed by a solid block having at least one flat portion.

  Moreover, in the said embodiment, although the number of the winding grooves formed in the bobbin 10 was three, it may replace with this and may be two.

  Moreover, in the said embodiment, although the circular shape of each winding groove | channel 15,16,17 was made into circular shape, it may replace with this, for example, may be an ellipse or a rectangular shape. When the circular shape is an ellipse or a rectangular shape, the processing of the winding groove and the winding operation of the optical fiber may become difficult, but the peripheral area of each winding groove can be made the same. In addition, a circumference area is an area of the area | region enclosed by the optical fiber coil with which each winding groove | channel was mounted | worn.

  By the way, in a semiconductor ring laser gyro using an optical fiber (one form of optical fiber gyro), as disclosed in Japanese Patent Application No. 2008-210260 (not disclosed at the time of the present application), a region surrounded by an optical fiber coil is used. It has been clarified by the present inventors that the measurement performance of the angular velocity differs depending on the area. Therefore, the multi-axis bobbin in which the winding areas of the winding grooves are the same can match the measurement performance for each axis, and is therefore effective as a multi-axis bobbin for a semiconductor ring laser gyro.

  The semiconductor ring laser gyro is an optical gyro that detects an angular velocity from a beat signal generated when the wavelengths of two lights emitted from both end faces of the semiconductor laser are different from each other due to the Sagnac effect. For this reason, as shown in FIG. 5, the semiconductor ring laser gyro includes a semiconductor laser 21 that emits light from both end faces, an optical fiber ring 22 that includes an optical fiber that forms a laser resonance circuit together with the semiconductor laser 21, and an optical fiber. An optical fiber coil 23 disposed in the ring 22, an optical branching device 24 for branching a part of light (CW light and CCW light) circulating in opposite directions in the optical fiber ring 22, and the optical branching device 24. A photodetector 25 for detecting an angular velocity from the frequency of a beat signal generated by superimposing the branched CW light and CCW light.

  Moreover, in the said embodiment, although the three winding grooves 15, 16, and 17 are formed concentrically, it does not necessarily need to form concentrically. For example, as in a bobbin 10A shown in FIGS. 6 (a) and 6 (b), the three winding grooves 15A, 16A, and 17A are shifted from each other so that the three light beams are formed even in a circular circumferential shape. Under conditions that do not cause interference between the fiber coils, the circular areas can be made to coincide with each other (the radius R is made to coincide). (The measured value of the angular velocity does not change even if the rotation center of each winding groove 15A, 16A, 17A is shifted.) Also, by making the circular shape of the three winding grooves 15A, 16A, 17A circular The workability of the winding groove processing step and the optical fiber winding step is improved. As shown in the figure, the entire shape of the bobbin 10A is a rectangular parallelepiped, but instead of the rectangular parallelepiped, for example, a cube may be used.

  Furthermore, the bobbin according to the present invention is not limited to the interference type optical fiber gyroscope and the semiconductor ring laser gyroscope, but can be applied to any type of optical gyroscope using an optical fiber.

10, 10A bobbin (bobbin for optical fiber coil)
11 outer surface 12 first plane part 13 second plane part 14 third plane part 15, 15A first winding groove 16, 16A second winding groove 17, 17A third winding groove 18 first optical fiber coil 19 first Two optical fiber coils 20 Third optical fiber coil 21 Semiconductor laser 22 Optical fiber ring 23 Optical fiber coil 24 Optical branching device 25 Optical detector

Claims (4)

An optical fiber coil bobbin used in an optical gyro that uses an optical fiber to detect the angular velocity of a moving object based on the Sagnac effect,
Three pairs of plane portions orthogonal to each other ;
Each of the three sets of the pair of plane portions that wrap around the optical fiber is wound around two pairs of plane portions, and in parallel with the other pair of plane portions. A solid block having three winding grooves on the outer surface,
The bobbin for an optical fiber coil , wherein a bottom surface of at least one of the three winding grooves is divided by another winding groove .   The bobbin for an optical fiber coil according to claim 1, wherein the solid block is a hexahedron. 3. The bobbin for an optical fiber coil according to claim 1, wherein each of the winding grooves has a circular shape with a circular shape having the same radius, and the rotation centers are shifted from each other . The three winding grooves are a first winding groove disposed near the center of the solid block and a second winding groove disposed orthogonally to the outside of the rotation center of the first winding groove. And a third winding groove,
4. The bobbin for an optical fiber coil according to claim 3, wherein the second winding groove and the third winding groove have different distances from the rotation center of the first winding groove.

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