JPS61108981A - Uniaxial differential type magnetism measuring instrument - Google Patents

Abstract

PURPOSE:To compensate precisely the inconsistency of a sensitive axis and to form a simple and small-sized structure by winding two magnetism detecting coils intersecting orthogonally with two ring cores respectively to detect magnetic fields in three axis directions. CONSTITUTION:The ring cores 2a, 3a of magnetic detectors 2, 3 are arranged on xy and zx planes respectively and the exciting coils 2b, 3b excite the ring cores 2a, 3b so as to generate magnetic flux. A magnetism detecting coil 2x is wound in the y-axis direction to detect the magnetic field in the x-axis direction and the x-axis direction becomes the sensitive axis. A magnetism detecting coil 2y is wound in the x-axis direction to detect the magnetic field in the y-axis direction. On the other hand, a magnetism detecting coil 3x is wound in the z-axis direction to detect the magnetic field in the x-axis direction and the x-axis direction becomes the sensitive axis. A magnetism detecting coil 3z is wound in the x-axis direction to detect the magnetic field in the z-axis direction. The inconsistency between the sensitive axes (x-axis direction) of the coils 2x and 3x is compensated on the basis of the outputs of the coils 2y, 3z.

Description

Detailed description of the invention (a) Industrial application field
Regarding shaft differential magnetic measuring instruments.

(B) Conventional technology Conventionally, in this type of single-axis differential magnetometer, a magnetic detection coil is wound on the outside of a ring core provided with an excitation coil, and a magnetic detection coil is wound in one direction across the ring core. It is constructed by arranging two magnetic detectors in parallel, and detects changes in the magnetic field in one direction, for example, in the X-axis direction in the coordinate space, from the difference in the outputs of the two magnetic detection coils. ing.

In this single-axis differential magnetometer, both magnetic detection coils must be provided with their sensitivity axes (for example, in the X-axis direction) aligned. If the sensitivity axes do not match and are shifted, magnetic fields in the y-axis direction and the two-axis direction will act on one of the magnetic detection coils, making it impossible to perform accurate magnetic detection. It has been extremely difficult to mechanically adjust the remagnetization detector to match the sensitivity axes.

Therefore, magnetic detectors in the y-axis direction and two-axis directions are provided separately from the remagnetization detector, and the deviation of the sensitivity axis is electrically corrected. In other words, another magnetic detector equipped with an excitation coil and a magnetic detection coil is installed in the ring core to detect the magnetic fields in the y-axis direction and the two-axis direction, and based on this output, the output of the remagnetization detector in the x-axis direction is was corrected.

However, in this case, three magnetic detectors had to be provided, which caused problems such as a large number of parts, a complicated structure, a large size, and an increase in cost.

(c) Purpose In view of the above, the present invention provides two ring cores having two magnetic detection coils vertically and horizontally in orthogonal directions, detects magnetic fields in three axial directions with the two ring cores, and detects mismatches in the sensitivity axes. It is an object of the present invention to provide a uniaxial differential magnetic measurement device that performs correction.

(d) Configuration In order to achieve the above-mentioned object, the present invention has the following features:
The xy plane and z in the coordinate space with the axis and two axes as the coordinate axes
A first ring core and a second ring core are provided in relation to the x-plane, and an excitation coil is wound around both ring cores, while an excitation coil is wound around the outside of the ring core in the X-axis direction of the first ring core. A magnetic detection coil in the y-axis direction is provided, and a magnetic detection coil in the A Z-axis magnetic detection coil wound around the outside of the ring core in the X-axis direction is provided, and an X-axis magnetic detection coil wound around the outside of the ring core is provided in the biaxial direction of the second ring core. It is characterized by correcting the mismatch of sensitivity axes in the remagnetization detection coil in the X-axis direction from the outputs of the magnetic detection coils in the y-axis direction and the two-axis direction.

(E) Embodiment Hereinafter, an embodiment of the present invention will be described in detail based on the drawings.

As shown in FIGS. 1 to 4, reference numeral 1 denotes a single-axis differential magnetometer, which is equipped with two magnetic detectors 2.3, and coordinates with the X-axis, the Y-axis, and two axes as coordinate axes. This detects the magnetic field in the X-axis direction in space.

The remagnetization detector 2.3 is configured by providing ring cores 2a, 3a with excitation coils 2b, 3b and two magnetic detection coils 2X, 2)r and 3x, 3z. The two ring cores 2a and 3a are arranged in a relationship between the xy plane and the zx plane in the coordinate space, with the first ring core 2a arranged on the xy plane and the second ring core 3a arranged on the zx plane. Furthermore, both ring cores 2a13a are provided so that the X axes passing through the centers of the ring cores 2a and 3a coincide with each other, and portions of their outer circumferential sides face each other closely.

Each excitation coil 2b, 3b winds each ring core 2as3a and is connected to an AC power source 2c, 3c, so as to excite magnetic flux in the ring core 2a, 3a.

Each magnetic detection coil 2x, 2-y, 3x, 3z is wound around the outside of each ring core 2a, 3a in the diametrical direction passing approximately through the center of this ring core 2a, 3a. and,
First magnetic detection coil 2x in first magnetic detector 2
is wound in the y-axis direction to detect a magnetic field in the x-axis direction perpendicular to the yz plane, and this x-axis direction is the sensitivity axis. Further, the second magnetic detection coil 2y is wound in the X-axis direction and detects a magnetic field in the Y-axis direction.

On the other hand, the first magnetic detection coil 3x in the second magnetic detector 3 is wound in the y-axis direction to detect a magnetic field in the X-axis direction perpendicular to the yz plane. This is the axis of sensitivity. Moreover, the second magnetic detection coil 3z
is wound in the X-axis direction and detects a magnetic field in the y-axis direction.

Furthermore, both ends of each magnetic detection coil 2X, 23F, 3X, and 32 are connected to a signal processing circuit (not shown), and changes in the magnetic field in the X-axis direction are detected from the difference between the outputs of both first magnetic detection coils 2x and 3x. It is configured as follows. And both second
magnetic detection coil 2y.

3z is configured to correct mismatch between the sensitivity axes (X-axis direction) of both first magnetic detection coils 2X%3x.

Next, the measurement operation of this single-axis differential magnetometer will be explained.

First, in the re-magnetic detector 2.3, if the sensitivity axes of the first magnetic detection coils 2x and 3x match, the y-axis direction and the y-axis direction of the first magnetic detection coil 3x in the second magnetic detector 3 The response output to magnetic fields in two axial directions is zero. Therefore, the outputs of both first magnetic detection coils 2x and 3x are detected differentially, and when the output is zero, there is no change in the magnetic field, and when this change occurs, a signal corresponding to the amount of change is output. It turns out.

Next, in this magnetic detector 2.3, if the sensitivity axes do not match and are shifted, for example, as shown in FIG. The X-axis direction, which is the sensitivity axis of the first magnetic detection coil 3x in the second magnetic detector 3, may be shifted by θ and φ with respect to the X-axis direction, which is the sensitivity axis of 2x. At this time, the magnetic fields in each axial direction are Hx, Hy, and Hz, and in the second magnetic detector 3, the response output of the first magnetic detection coil 3x to the y-axis magnetic field Hy, and the response output to the z-axis magnetic field Hz. is as follows.

Hy-A3x-sinθcosφ Hz-A3x-sinφ In addition, A3x is the gain of the first magnetic detection coil 3x, A3 x=signal output/input magnetic field in the X-axis direction.

On the other hand, the y-axis direction magnetic field Hy and the biaxial direction magnetic field Hz are detected by the second magnetic detection coils 2y and 3z, respectively, and the A3
It outputs F-Hy and Az-Hz.

Incidentally, Ay and Az are also respectively the second magnetic detection coils 2y.
, 3z, A7-signal output/yX-axis direction input magnetic field Az=signal output/two-axis direction input magnetic field.

Therefore, AyHy+HyA3xs inθcosφ=OAzHz
The inclination θ (displacement) is corrected by adding the outputs of the second magnetic detection coils 2y and 3z to the output of the first magnetic detection coil 3x so that +H2A3xsinφ±0. That is, Ay=−A3 x −, s
Correction is made so that inθco, sφAz=−A3x−sinφ holds. This correction is performed for the second magnetic detection coils 2y, 3z with respect to the first magnetic detection coil 3x.
This is done by adjusting the winding width of the magnetic detection coils 3x, 2y, and 3z, or by adjusting the amplification factors of the outputs of the first and second magnetic detection coils 3x, 2y, and 3z.

As a result, it can be considered that the sensitivity axes (X-axis direction) of both the first magnetic detection coils 2x and 3x coincide with each other, and in this state, a change in the magnetic field Hx in the X-axis direction is detected.

Note that the arrangement of both ring cores 2a and 3a is not limited to that in the embodiment, but may be arranged in a relationship between two orthogonal planes (xy plane and zx plane).

(f) Effects As described above, according to the uniaxial differential magnetometer of the present invention, two magnetic detection coils are wound orthogonally around each of two ring cores, and in addition to the detection magnetic field in the X-axis direction, Also detects magnetic fields in the y-axis direction and two-axis directions.

This ensures that there is no discrepancy in the sensitivity axis.
・Can be corrected. In particular, since there is no need to provide separate magnetic detectors to detect magnetic fields in the y-axis and two-axis directions as in the past, the number of parts can be reduced, and the structure can be simplified and made smaller. can.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, in which FIG. 1 is a schematic perspective view of a single-axis differential magnetometer, FIG. 2 is a schematic plan view of the same, and FIG.
The figure is a schematic side view of the same, FIG. 4 is a schematic plan view of the magnetic detector,
FIG. 5 is an explanatory diagram of the coordinate space showing the deviation of the sensitivity axis. 1: Single-axis differential magnetometer, 2.3: Magnetic detector, 2a, 3a: Ring core, 2b, 3b: Excitation coil, 2x, 3x: First magnetic detection coil, 2y, 3z: Second Magnetic detection coil.

Claims (1)

[Claims] (1) A first ring core and a second ring core are provided as shown in the relationship between an xy plane and a zx plane in a coordinate space whose coordinate axes are the x-axis, y-axis, and z-axis, and an excitation coil is provided in both ring cores. x of the first ring core while being wound
A magnetic detection coil in the y-axis direction is provided which is wound around the outside of the ring core in the axial direction, and a magnetic detection coil in the x-axis direction is provided which is wound around the outside of the ring core in the y-axis direction of the first ring core. The second ring core is provided with a z-axis magnetic detection coil that winds around the outside of the ring core in the x-axis direction of the ring core, and an x-axis magnetic detection coil that winds around the outside of the ring core in the z-axis direction of the second ring core. The single-axis differential is characterized in that a magnetic detection coil is provided in the y-axis direction and the z-axis direction, and a discrepancy in the sensitivity axes of the two magnetic detection coils in the x-axis direction is corrected from the outputs of the magnetic detection coils in the y-axis direction and the z-axis direction. type magnetic measuring instrument.