JP5190946B2 - Buoyancy-type magnetic orientation sensor - Google Patents

Description

  The present invention relates to a magnetic direction detection element configured by a fluxgate type direction meter that detects geomagnetism and detects an orientation, and in particular, an annular magnetic core housed in an annular core case floats on a liquid in an annular bobbin. The present invention relates to a buoyancy type magnetic orientation detection element.

  One of the fluxgate type magnetic azimuth sensors configured to detect the north-south-north-west of geomagnetism is a buoyancy-type magnetic azimuth sensing element as described in Patent Document 1. An example of a conventional configuration of this buoyancy type magnetic orientation sensor is shown in FIGS. 4, 5, and 6. 4 is a top view of the inside, FIG. 5 is a perspective view of the entire device, and FIG. 6 is a front half sectional view. As shown in FIG. 6, the annular magnetic core 12 housed in the annular core case 34 is floated by enclosing the liquid 13 occupying almost half in the internal space of the nonmagnetic annular bobbin 31, as shown in FIG. An exciting winding 22 is wound using a metal wire insulated from the inner peripheral surface of the center hole of the annular bobbin 31 through the outer peripheral surface of the annular bobbin 31 with enamel or the like. Two detection windings 21 passing through the surface and orthogonal to the radial direction are wound and formed. The magnetic azimuth sensing element having such a structure is used in an azimuth detector used in a device that is particularly severely shaken.

  Orientation detectors are used in various devices, but there is a great market demand for miniaturization of devices, and the buoyancy-type magnetic orientation detection element needs to be miniaturized in order to meet this demand. In the case of the buoyancy-type magnetic azimuth detecting element, the shape is almost determined by the shape of the annular bobbin 31 containing the liquid, and it is necessary to reduce the shape of the annular bobbin 31 in order to reduce the size.

JP-A-8-219791

  One of the main performances of the buoyancy-type magnetic azimuth sensing element is tilt correction characteristics. FIG. 7 is a cross-sectional view showing the inside of the annular bobbin 31 when the buoyancy-type magnetic bearing detector is tilted. The feature of the buoyancy-type magnetic azimuth sensing element is that the annular magnetic core 12 remains horizontal even when the buoyancy-type magnetic azimuth sensing element is tilted as shown in FIG. The azimuth accuracy is almost unchanged. For example, when the azimuth accuracy when tilted by ± 10 ° from the horizontal is a deviation within 1 ° with respect to the horizontal orientation accuracy, the angle of this deviation is the inclination correction angle.

  However, in the conventional buoyancy-type magnetic orientation detection element, when the annular bobbin and the annular core case are reduced in size, the annular core case in the annular bobbin is also reduced in size and weight, thereby causing variation in the position where the annular core case floats. In addition, position variations due to rotation are likely to occur, and in particular, there is a problem of affecting the tilt correction characteristics when the above-mentioned device is shaken and tilted. That is, there is a problem that the predetermined inclination correction angle cannot be satisfied, and an error occurs in the measured azimuth even when the fluctuation is within a predetermined range.

  An object of the present invention is to solve these problems, and to provide a small buoyancy-type magnetic azimuth detecting element having excellent tilt correction characteristics satisfying a predetermined tilt correction angle and having high reliability.

In order to solve the above-described problem, the buoyancy type magnetic orientation detection element of the present invention encloses a liquid occupying almost half of the space in a non-magnetic annular bobbin having an annular space, and a required buoyancy on the liquid surface. The annular magnetic core is accommodated in the annular core case and floated, and an exciting winding is wound from the inner peripheral surface of the central hole of the annular bobbin through the outer peripheral surface, and the outer periphery of the center and outer periphery of the annular bobbin In a buoyancy-type magnetic azimuth sensing element formed by winding two detection windings perpendicular to the radial direction through a surface, a plurality of convex portions are provided on the outer peripheral surface of the annular core case, and the convex portions are opposed to the convex portions. A concave portion having a shape corresponding to the shape of the convex portion is provided on the inner surface of the annular bobbin, or a plurality of concave portions are provided on the outer peripheral surface of the annular core case, and the annular bobbin facing the concave portion is provided. The inner surface has a shape corresponding to the shape of the recess. Characterized in that the provided parts.

  The convex portion may be a semi-cylindrical shape parallel to the central axis of the annular core case, and the concave portion may be a semi-cylindrical shape parallel to the central axis of the annular bobbin.

  As described above, according to the present invention, the rotation of the annular core case within the annular bobbin prevents the position of the annular core case from being varied regardless of how the attached device is shaken within a predetermined range. Thus, a small buoyancy type magnetic azimuth sensing element having excellent tilt correction characteristics satisfying a predetermined tilt correction angle and having high reliability can be obtained.

  Embodiments of the present invention will be described below with reference to the drawings.

  1, 2 and 3 are diagrams showing an embodiment of a buoyancy type magnetic azimuth sensing element according to the present invention. FIG. 1 is a top view of the inside of the buoyancy type magnetic azimuth sensing element, and FIG. 2 is a buoyancy type. FIG. 3 is a front half sectional view of the buoyancy type magnetic azimuth sensing element.

  As shown in FIG. 3, a liquid 13 occupying almost half of the space is enclosed in a non-magnetic annular bobbin 11 having an annular space, and the annular magnetic core 12 is provided with the required buoyancy on the liquid surface. As shown in FIG. 2, the exciting winding 22 is wound from the inner peripheral surface of the central hole of the annular bobbin 11 through the outer peripheral surface thereof, as shown in FIG. Two detection windings 21 passing through the outer peripheral surface and orthogonal to the radial direction are wound. Further, as shown in FIG. 1, the rotation of the annular core case 14 in the annular bobbin 11 is prevented between the outer peripheral surface of the annular core case 14 and the inner surface of the annular bobbin 11 facing the outer peripheral surface. In the present embodiment, four convex portions 19 are provided on the outer peripheral surface of the annular core case 14, and the convex portion 19 is provided on the inner surface of the annular bobbin 11 facing the convex portion 19. A recess 20 having a shape corresponding to the shape is provided.

  A specific example of the buoyancy-type magnetic bearing sensor according to the present embodiment will be described below. The annular magnetic core 12 is made of a metal plate of a high magnetic permeability magnetic material, is made of resin, and is accommodated in an annular core case 14 having an outer diameter of 20 mm, an inner diameter of 10 mm, and a height of 3 mm. Further, the annular core case 14 is made of resin, and is floated and held in a liquid 13 enclosed in an annular bobbin 11 having an outer diameter φ28 mm, an inner diameter φ24 mm, a height 20 mm, and a center hole 15 having a diameter 8 mm in the center. . As the liquid in the annular bobbin, a liquid made of a fluorine compound, having electrical insulation and having a specific gravity of about 2 is used.

  The convex portion 19 of the annular core case 14 has a semicylindrical shape parallel to the central axis of the annular core case 14, and the concave portion 20 has a semicylindrical shape with a radius of 1 mm parallel to the central axis of the annular bobbin 11.

  The tilt correction characteristic was measured by actually fabricating the buoyancy type magnetic orientation detection element of this example. FIG. 8 shows the result of calculating the azimuth angle from the output of the sensing element when the inclination angle is 0 ° (horizontal), + 10 °, and −10 °. Here, the buoyancy type magnetic azimuth sensing element is not turned, but the azimuth angle is fixed and tilted in the direction of 0 °. As a comparative example, a buoyancy type magnetic azimuth sensing element having a conventional structure having the same shape as that of the present embodiment and not provided with the convex portions 19 and the concave portions 20 was also manufactured and measured in the same manner. The result is shown in FIG. As shown in FIG. 9, the position of the buoyancy-type magnetic azimuth sensing element using the conventional annular core case is not fixed because it has a degree of freedom in the direction of rotation inside the annular bobbin. As a result, the data is not reproducible and the characteristics vary greatly due to repeated measurement.

  On the other hand, as shown in FIG. 8, the buoyancy-type magnetic bearing detector according to the present invention can prevent rotation inside the annular bobbin, and therefore has little variation in characteristics. As a result, a small buoyancy type magnetic azimuth sensing element having excellent tilt correction characteristics that always satisfies the tilt correction angle of 0.1 degrees and high reliability was obtained.

  For example, in the case of one or two protrusions or recesses, the overall weight balance is lost and the inclination tends to tilt in a certain direction. Good installation number is good. For this purpose, it is desirable to install three or more symmetrically with respect to the central axis of the annular bobbin or the annular core case.

  In addition, the present invention is not limited to the above-described embodiment, and the shape, structure, configuration, and material of the annular bobbin and the core are designed in accordance with the characteristics, shape, and the like of the target buoyancy type magnetic orientation detection element. be able to. The shape of the convex part and the concave part is not limited to the embodiment. For example, the convex part can be provided on the annular bobbin and the concave part can be provided on the annular core case. The shape of the convex part is a center such as a hemispherical shape. A shape with a short axial length may be used.

1 is a top view of the inside of a buoyancy type magnetic bearing sensor according to an embodiment of the present invention. 1 is a perspective view of a buoyancy type magnetic orientation detection element according to an embodiment of the present invention. 1 is a front half sectional view of a buoyancy type magnetic bearing sensor according to an embodiment of the present invention. The top view inside the conventional buoyancy type magnetic direction detection element. The perspective view of the conventional buoyancy type magnetic direction detection element. The front half sectional view of the conventional buoyancy type magnetic direction detection element. Sectional drawing which shows the mode inside the annular bobbin at the time of the inclination of a buoyancy type magnetic direction detection element. The measurement result of the inclination correction characteristic of the Example of the buoyancy type magnetic direction detection element of this invention. The measurement result of the inclination correction characteristic of the comparative example of the conventional buoyancy type magnetic direction detection element.

Explanation of symbols

11, 31 Annular bobbin
12 annular magnetic core 13 liquid 14, 34 annular core case 15 center hole 19 convex portion 20 concave portion 21 detection winding 22 excitation winding

Claims (2)

In a non-magnetic annular bobbin having an annular space, a liquid occupying almost half of the space is enclosed, the liquid surface is given a required buoyancy, and the annular magnetic core is accommodated in an annular core case and floated, An excitation winding is wound from the inner peripheral surface of the center hole of the annular bobbin through the outer peripheral surface, and two detection windings passing through the center and outer peripheral surface of the annular bobbin and perpendicular to the radial direction are wound. In the buoyancy type magnetic orientation sensor,
A plurality of convex portions are provided on the outer peripheral surface of the outer side of the annular core case, and a concave portion having a shape corresponding to the shape of the convex portion is provided on the inner surface of the annular bobbin facing the convex portion, or the annular shape A buoyancy-type magnetic orientation characterized in that a plurality of recesses are provided on the outer peripheral surface of the outer side of the core case, and a protrusion having a shape corresponding to the shape of the recess is provided on the inner surface of the annular bobbin facing the recess. Sensing element. 2. The buoyancy mold according to claim 1 , wherein the convex portion has a semi-cylindrical shape parallel to the central axis of the annular core case, and the concave portion has a semi-cylindrical shape parallel to the central axis of the annular bobbin. Magnetic orientation detection element.

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