JPH04305158A - Magnetic rotation detector - Google Patents

Abstract

PURPOSE:To obtain the detector of high resolving power by passing the alternating change of the magnetic flux leaked from a multipole magnetized magnet having a narrow magnetizing pitch interval through a detection element in the thickness direction thereof to collectively detect the same. CONSTITUTION:A multipole magnetized magnet 4 is alternately magnetized with N-poles and S-poles and the magnetic fluxes of lines 1 of magnetic force are discharged to the air from the N-poles toward the S-poles. Since a high magnetic permeability magnetic layer 3 is arranged so as to be adjacent to a detection part 1 detecting magnetic flux density, the lines of magnetic force 10 are attracted to the detection part 1. The N-poles and S-poles of the magnet 4 alternately appear with respect to the detection part 1 by the rotation of a rotary body 2 and the magnetic flux density passing through the detection part 1 changes and the detection part 1 detects the magnetic fluxes from the N-poles nearest to said magnetic flux density. By this constitution, the detection part 1 detects the change of the alternating leak magnetic flux from the magnet to measure an angle of rotation.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic rotation speed detection device, and more particularly to a novel magnetic rotation speed detection device equipped with a detection element structure having high resolution.

0002

[Prior Art] Conventional magnetic rotational speed detection devices are disclosed in Japanese Patent Laid-Open No. 62-235523 and Japanese Patent Laid-open No. 62-2188.
For example, as shown in FIG. 6, a rotating body 52 including a multipolar magnetized magnet 51 and a multipolar magnetized magnet 5
In this technology, a magnetic flux detection means 53 for detecting leakage magnetic flux from 1 is arranged substantially parallel to the axial direction of the rotating body 52, and the leakage magnetic flux that changes alternately due to the rotation of the multipolar magnetized magnet 51 is detected. be.

0003

[Problems to be Solved by the Invention] The magnetic flux detecting means 53 of the magnetic rotation detecting device has the detecting element of the detecting section for measuring the intensity of the magnetic flux density arranged in a direction perpendicular to the magnetic flux. It is not possible to detect alternating changes in magnetic flux density unless the size of the magnetization pitch is smaller than the magnetization pitch interval.In order to reduce the magnetization pitch interval and detect the rotation angle with high resolution, the size of the sensing element must be The problem was that there were restrictions and it was difficult.

SUMMARY OF THE INVENTION The present invention focuses on the problems of the prior art described above and aims to provide a magnetic rotation speed detection device having high resolution.

[0005]

[Means for Solving the Problems] The means for achieving the above object is described in the claims, and includes a sensing device in which sensing element surfaces are arranged in a direction parallel to leakage magnetic flux from a multipolar magnetized magnet. A magnetic type configured to detect alternating changes in magnetic flux intensity passing in the thickness direction of the sensing element by laminating a high permeability magnetic layer on at least one side adjacent to the sensing element surface. This is achieved by a rotation detection device.

[0006]

[Function] With the above configuration, the leakage magnetic flux from the multi-pole magnetized magnet is prevented from crossing in the direction perpendicular to the detection element surface, since the sensing element surface is arranged parallel to the leakage magnetic flux. Even if the magnetization pitch becomes small, changes in the magnetic flux density can be detected even if the magnetization pitch is small, and leakage magnetic flux is prevented by the sensing element laminated with high permeability magnetic material. Since the magnetic flux passes through the sensing element surface in a concentrated manner, minute changes in magnetic flux density can be effectively detected.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained below based on the drawings. FIG. 1 is an explanatory side view showing the configuration of an embodiment of the present invention, in which a detection unit 1 that detects the magnitude of magnetic flux density is arranged in a direction parallel to the direction of leakage magnetic flux of a multipolar magnetized magnet 4. A flat surface of the sensing element 11 formed inside the sensing portion 1 is disposed. In other words, the magnetization direction of the multipolar magnetized magnet 4 and the detection element 11
are perpendicular to each other. The detection unit 1 includes a detection element 11, a protective film 12 that protects the detection element 11, and a high permeability magnetic layer 13.
and a protective resin layer 3 that packages the entire detection section 1. The detection element 11 uses, for example, a semiconductor magnetoresistive element of indium antimony (InSb),
As shown in FIG. 2, a substrate 14 such as alumina or glass,
An insulating film 15 is formed on the substrate 14 by sputtering. This insulating film 15 is interposed between the substrate 14 and the sensing element 11, and is used to prevent the deposited film of the magnetoresistive element from peeling off due to the generation of stress due to the difference in coefficient of linear expansion.
4 and the sensing element 11. The sensing element 11 as described above is formed on this insulating film 15 by a vapor deposition method. The sensing elements 11 are patterned, for example, in the arrangement shown in FIG. Further, after forming the sensing element 11, the electrode 16 is formed by a vapor deposition method.

As shown in FIG. 1, a protective film 12 for protecting the sensing element 11, for example silicon oxide (SiO2), is formed by sputtering to form a thin film to constitute the sensing part 1, and furthermore, a protective film 12 for protecting the sensing element 11 is formed by sputtering. Then, a high permeability magnetic layer 13 made of a silicon steel plate or the like is arranged. The high permeability magnetic layer 13 acts to focus leakage magnetic flux from the multipolar magnetized magnet 4 and causes the focused magnetic flux to pass through the detection section 1 . The sensing element 11 is
A Hall element as a magnetic semiconductor may be used, and for example, a wafer made of a single crystal of gallium arsenide (GaAs) is used.

Next, the operation of the embodiment will be explained based on FIG. The multipolar magnetized magnet 4 is magnetized alternately to have north and south poles. Since the present invention aims to provide a device that detects a rotation angle with high resolution, for example, the magnetization pitch interval of the multipolar magnetized magnet 4 is 0.5 mm, and the material is
For example, fine powder of manganese-aluminum alloy (MnAl) is compressed and then magnetized using a magnetizer. From such a multipolar magnetized magnet 4, magnetic flux indicated by lines of magnetic force 10 is emitted into the air from the north pole toward the south pole.

Since the high permeability magnetic layer 13 is disposed adjacent to the detection section 1 for detecting magnetic flux density, the lines of magnetic force 10 are drawn toward the detection section 1. Due to the rotation of the rotating body 2, the N and S poles of the multipolar magnetized magnet 4 appear alternately with respect to the detection unit 1, and the magnetic flux density passing through the detection unit 1 changes, and the magnetic flux density passing through the detection unit 1 changes. will detect the magnetic flux from the N pole closest to this. In this way, the detection unit 1 detects changes in the alternating leakage magnetic flux from the multipolar magnetized magnet 4 and measures the rotation angle.

As shown in FIG. 5, the detecting section 1 detects the leakage magnetic flux from the multi-polar magnetized magnet 4 magnetized at a pitch of 0.5 mm, for example, so the thickness of the detecting section 1 is equal to the magnetizing pitch interval. The detection unit 1 must be the detection element 11.
It is formed from only.

In addition, the multipolar magnetized magnet 4 is arranged only in necessary parts to reduce manufacturing costs, and the main body of the rotating body 2 is covered with a resin layer 5.
may be formed by Further, if necessary, a protective layer 6 for protecting the multipolar magnetized magnet 4 may be formed on the outer surface (see FIG. 1).

When the arrangement of the sensing elements 11 shown in FIG. 3 is specifically implemented, it is possible to increase the signal level by performing operational amplification in the equivalent circuit shown in FIG.

[0014]

[Effects of the Invention] By carrying out the present invention, alternating changes in leakage magnetic flux from a multipolar magnetized magnet with a narrow magnetization pitch disposed on a rotating body are passed through the thickness direction of the detection element and concentrated. It is possible to provide a magnetic rotation detection device capable of detecting a rotation angle with high resolution.

[Brief explanation of drawings]

FIG. 1 is a side view showing the configuration of an embodiment of the present invention.

FIG. 2 is a perspective view showing the configuration of an embodiment of a sensing element according to the present invention.

FIG. 3 is a diagram showing an arrangement pattern of sensing elements of the present invention.

FIG. 4 is a diagram showing an equivalent circuit for the operation of FIG. 3;

FIG. 5 is a perspective view showing the arrangement of a rotating body and a sensing element in another embodiment.

FIG. 6 is a perspective view of the prior art.

[Explanation of symbols]

1 Detection part 2 Rotating body 3 Protective resin layer 4 Multipolar magnetized magnet 5 Resin layer 6 Protective layer 10　　　　　Magnetic field lines 11 Detection element 12 Protective film 13 High permeability magnetic layer 14　　　　Substrate 15 Insulating film 16 Electrode

Claims (1)

[Claims] 1. A magnetic rotation detection device in which a multipolar magnetized magnet is formed as a part of a rotating body, and the rotational speed of the rotating body is detected by detecting a change in leakage magnetic flux density from the magnet, comprising: By including a sensing portion having a sensing element surface in a direction parallel to the leakage magnetic flux from the magnet, and a high permeability magnetic layer provided on a surface adjacent to the sensing element surface, A magnetic rotation detection device characterized by detecting alternating changes in the intensity of passing magnetic flux.