JPS5945109B2 - magnetic field detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates in particular to the structure of a rotating magnetic piece in an apparatus for detecting a magnetic field vector by placing a fixed coil around a magnetic piece that rotates at a constant speed within a magnetic field.

Figure 1 shows a conventional magnetic field detection device that uses magnetic pieces that rotate at a constant speed. In the figure, 1 is a rotating shaft, 2 is a magnetic pole piece embedded in the rotating shaft 1, 3 is a bearing, and 4 is a fixed It is a coil.

As shown in the figure, the magnetic piece was embedded in the rotating shaft, which caused distortion in the shaft, resulting in large errors in magnetic field detection due to the centering of the rotating shaft. By adopting a structure in which a magnetic piece is not embedded in the rotating shaft, the present invention greatly reduces errors in the magnetic field vector detection device due to core runout of the rotating shaft, which has been a problem in the past.

An embodiment of the present invention is shown in FIGS. 2 and 3.

In FIG. 2, 1 is a rotating shaft, and 5 is a hollow cylindrical magnetic body fixed to a fixed coil 4. In FIG.

As shown in the figure, 6 is a disk in which plate-shaped magnetic pole pieces 7 are embedded in the radial direction, and rotates together with the rotating shaft.

FIG. 2A is a sectional view taken along line AA in FIG.

As shown in the figure, only the disk 6 rotates together with the rotating shaft 1.

Since there is no magnetic material embedded in the rotating shaft, there is no distortion of the shaft, the load is light, and there is almost no core runout. In addition, since there is no core deviation, even if the magnetic body is slightly magnetized, it has little effect on the detection error of the magnetic field vector.

Fig. 3 shows another embodiment, and Fig. 3A shows A-A in Fig. 3.
FIG. In the figure, reference numerals 8 and 8a indicate magnetic pole pieces, which are fixed to both ends of the magnetic body 5 and rotate together with the rotating shaft. In the embodiment shown in Fig. 3, no machining is performed to embed the rotating magnetic piece, so there is no risk of deformation of the shaft, etc., but the rotation is stable and there is almost no error in detecting the magnetic field vector due to center runout of the rotating shaft. . Further, the structure of the rotating magnetic field piece of the device according to the present invention is easy to mechanically adjust. As described above, according to the present invention, a magnetic field detection device with less rotational unevenness can be realized.

Since this device is suitable for use in a moving body, it can be used in a device for detecting unit coordinates of a vehicle by detecting the direction of the earth's magnetic field. Therefore, its application range is extremely wide, such as as a driver's guide and as a sensor for an automatic vehicle monitor (AVM) system.

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional view showing a rotating part of a magnetic piece in a conventional device for detecting magnetic field vectors, FIGS. 2 and 3 are vertical cross-sectional views showing an embodiment of the present invention, and FIG. , second
Figures A and 3A are cross-sectional views of the portions shown in Figures 1, 2, and 3, respectively. 1... Rotating shaft, 2... Rotating magnetic body, 3... Bearing, 4... Fixed coil,
5...Magnetic material, 6...Disc, 7,7a
, 8, 8a... Magnetic pole piece.

Claims (1)

[Scope of Claims] 1. A device that rotates a magnetic pole piece in a magnetic field and detects a magnetic field vector using a voltage induced in a fixed coil, comprising: a coil body having a through hole in the center; and a rotating shaft passing through the coil body. a magnetic body that is a hollow cylinder coaxial with the rotating shaft and passes through the coil body; a disk fixed to the rotating shaft at both ends of the coil body; and a magnetic body extending from the center of the first disk. a first magnetic pole piece that is embedded in one radial direction and moves together with the magnetic body; and a first magnetic pole piece that is embedded in a direction opposite to the one radial direction from the center of the other disk and moves together with the magnetic body. 1. A magnetic field detection device comprising: two magnetic pole pieces. 2. A device that rotates a magnetic pole piece in a magnetic field and detects a magnetic field vector using a voltage induced in a fixed coil, which includes a coil body having a through hole in the center, a rotating shaft passing through the coil body, and a rotating shaft fixed to the rotating shaft. a coaxial hollow cylindrical magnetic body passing through the coil body; a first magnetic pole piece having one end fixed to one end of the magnetic body; and a first magnetic pole piece having one end fixed to the other end of the magnetic body in a direction opposite to the first magnetic pole piece. and a second magnetic pole piece having one end fixed to the magnetic field detecting device.