JP2002005613A - Rotational angle detecting sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotational angle detecting sensor for improved sensitivity, at detecting a neutral point of a reference for detecting a rotational angle, while gap characteristics within a neutral point detection angle range is stabilized. SOLUTION: A Hall IC3 is fitted to a circuit board 5. Since a magnetic piece 6 of almost the same size with the Hall IC3 is pasted on the side of the circuit board 5, which is opposite to the Hall IC3 side for fixed arrangement, when a magnetic field component (line of magnetic force 7) vertical to a magnetic-pole surface of a neutral-point detecting magnet 2 is detected with the Hall IC3, while the neutral-point detecting magnet 2 moves relative to the Hall IC3, a magnetic field (magnetic field detected by the Hall IC) in the vertical direction is intensified by magnetic collection effect of the magnetic piece 6, when the Hall IC3 is located directly above a magnetic pole of the neutral-point detecting magnet 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic rotation angle detecting sensor used for detecting, for example, a steering wheel angle of a vehicle, and more particularly to a neutral point which is a reference for detecting a rotation angle. The present invention relates to a rotation angle detection sensor for improving sensitivity at the time of stabilization and stabilizing a gap characteristic in a neutral point detection angle range.

[0002]

2. Description of the Related Art As a conventional rotation angle detecting sensor of this kind, for example, Japanese Patent Publication No.
"" Development of High Resolution Encoder "HONDA R & D
Technical Review. 1992 Vol
4. P195-].

A sensor for detecting a rotation angle such as a rotation angle of a steering wheel of a vehicle can be realized by combining a magnet ring and a magnetic sensor as shown in the above-mentioned patent publication and the above-mentioned literature.

In these rotation angle detection sensors, a magnetic sensor for detecting a rotation angle and a rotation direction and a magnetic sensor for detecting a neutral point serving as a reference of the angle are required.

[0005] Among them, an MR (magnetic resistance) element is used for a magnetic sensor used for angle detection. On the other hand, an MR (magnetoresistive) element is used as a magnetic sensor for detecting a neutral point serving as a reference in detecting a rotation angle in the case of the technology disclosed in the former patent publication. Use of a Hall IC is easier in terms of signal processing as in the technique disclosed in the latter document.

[0006]

However, any of the above-described conventional magnetic sensors has the following problems.

(1) The magnetic flux near the pole tip of the neutral point detecting magnet spreads outside the pole tip of the neutral point detecting magnet 101 as shown in FIGS. The angle range of the magnetic field strength at which the Hall IC 102 for detecting a magnetic field component perpendicular to the magnetic pole surface of the point detection magnet 101 is turned on / off greatly varies depending on the gap 103 from the neutral point detection magnet 101 to the magneto-sensitive surface of the Hall IC 102. I do. FIG. 3A shows that when the gap 103 is small, the sensitivity when detecting the neutral point which is a reference for detecting the rotation angle is good. On the other hand, FIG. 3B shows that when the gap 103 is large, the sensitivity when detecting the neutral point which is a reference for detecting the rotation angle is low.

Therefore, in order to make the angle range as the neutral point accurate, it is necessary to mount a magnetic sensor including the Hall IC 102 so that the gap 103 is constant.

(2) The above (1) can be improved by enclosing it with an opposite magnetic pole as shown in FIG. 10 of the technique disclosed in the latter document. However, the magnetizing yoke for magnetizing the magnet can be improved. The structure becomes complicated, and the magnetization process increases due to the complicated magnetization yoke structure.

(3) The distance from the neutral point detecting magnet to the magneto-sensitive surface of the Hall IC differs depending on the type of the magnetic sensor, so that even if the angle detecting MR element can be detected,
In some cases, the neutral point cannot be detected in the Hall IC.

In view of the above circumstances, the present invention can improve sensitivity when detecting a neutral point which is a reference in detecting a rotation angle, and stabilize a gap characteristic in a neutral point detection angle range. It is an object of the present invention to provide a rotation angle detection sensor capable of detecting the rotation angle.

[0012]

In order to achieve the above object, according to the first aspect of the present invention, a magnet for detecting a neutral point has a hole I.
In the process of moving relative to C, the Hall IC detects a magnetic field component perpendicular to the magnetic pole surface of the neutral point detecting magnet, and determines the neutral point angle detection range of the magnetic field strength at which the Hall IC turns on and off. A rotation angle detection sensor for detecting a rotation angle of the rotating operation body, wherein a magnetic material piece having substantially the same size as the Hall IC is fixed to the back side of the Hall IC mounting position on the circuit board on which the Hall IC is mounted. It is characterized by being arranged.

According to a second aspect of the present invention, in the rotation angle detecting sensor according to the first aspect, the Hall IC is a ring magnet in which N and S poles are alternately arranged by a suitably selected number over the entire circumference of the ring. The present invention is characterized in that a magnetic field component perpendicular to the magnetic pole surface is detected for a neutral point detection magnet that is rotatably mounted along the circumference.

According to a third aspect of the present invention, in the rotation angle detecting sensor according to the second aspect, the ring magnet is magnetized in an axial direction of the ring.

According to the first aspect of the present invention, a magnetic piece having a high magnetic permeability such as permalloy, which is substantially the same size as the Hall IC, is attached to the back side of the Hall IC of the circuit board on which the Hall IC is mounted. In the process of moving the neutral point detecting magnet relative to the Hall IC, the Hall IC detects a magnetic field component perpendicular to the magnetic pole surface of the neutral point detecting magnet. When the Hall IC is directly above the magnetic pole, the distribution is
The magnetic field in the vertical direction (the magnetic field detected by the Hall IC) becomes stronger.

On the other hand, at a position slightly away from the end of the magnetic pole, the horizontal component of the magnetic field is mainly attracted to the magnetic piece, so that the magnetic field detected by the Hall IC does not become strong.

As a result, the magnetic material piece allows the Hall IC to be used.
The vertical component of the magnetic field applied to the magnetic pole increases when the magnetic field is above the magnetic pole, but sharply decreases when the magnetic pole moves away from the magnetic pole.

With this effect, the Hall IC can be removed from the magnet surface.
Rotation angle detection sensor that can detect the rotation angle such as the steering wheel angle of the vehicle even if the gap to the sensing part changes does not greatly change the neutral point detection angle range even if the magnetic sensor is precisely assembled Can be realized.

According to the second aspect of the present invention, there is provided a magnet for detecting a neutral point which is rotatably mounted along the inner circumference of a ring magnet in which N and S poles are alternately arranged by a suitably selected number over the entire circumference of the ring. When detecting the magnetic field component perpendicular to the magnetic pole surface by the Hall IC, even if the gap from the magnet surface to the sensing part of the Hall IC changes, the neutral point detection angle range does not greatly change. As in the case of the present invention, a rotation angle detection sensor capable of detecting a rotation angle such as a steering wheel angle of a vehicle without precise assembly can be realized.

According to the third aspect of the present invention, since the ring magnet magnetized in the axial direction of the ring is used, even if the arrangement of the ring magnet and the magnetic sensor is the same, the angle of the steering wheel of the vehicle is reduced. Such a rotation angle can be detected.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a rotation angle detection sensor according to the present invention will be described below in detail with reference to the drawings.

1 and 2 show a schematic configuration of an embodiment of a rotation angle detection sensor according to the present invention. FIG. 1 is a sectional view and FIG. 2 is a perspective view.

In the process of rotating the neutral point detecting magnet 2 relative to the Hall IC 3, the rotation angle detecting sensor 1 uses the magnetic field detecting unit 4 of the Hall IC 3 to move the neutral point detecting magnet 2 to the magnetic pole surface of the neutral point detecting magnet 2. Detect vertical magnetic field components.

Thus, it is possible to construct a basic configuration of a rotation angle detection sensor capable of detecting a rotation angle such as a steering wheel angle of a vehicle with reference to a neutral point angle detection range of a magnetic field intensity at which the Hall IC 3 is turned on / off.

However, this basic configuration alone is substantially the same as a conventional rotation angle detection sensor. As described above, the magnetic flux near the magnetic pole tip of the neutral point detecting magnet 2 spreads outside the magnetic pole. Go. For this reason, the angle range of the magnetic field intensity in which the Hall IC 3 for detecting the magnetic field component perpendicular to the magnetic pole surface is turned on / off greatly changes depending on the gap from the neutral point detecting magnet 2 to the magneto-sensitive surface of the Hall IC 3.

That is, in the rotation angle detection sensor having only this basic configuration, it is necessary to assemble a magnetic sensor including the Hall IC 3 so that the gap is constant in order to make the angle range as the neutral point accurate. .

On the other hand, in the rotation angle detection sensor according to the present invention, a magnetic piece 6 having substantially the same size as the Hall IC 3 is fixedly arranged on the back side of the Hall IC 3 of the circuit board 5 on which the Hall IC 3 is mounted. are doing. In addition,
As the magnetic piece 6, a magnetic piece having a high magnetic permeability such as permalloy is used.

As described above, a magnetic piece 6 having a high magnetic permeability, such as permalloy, having substantially the same size as the Hall IC 3 is fixedly arranged on the back side of the Hall IC 3 of the circuit board 5 on which the Hall IC 3 is mounted. Figure 3
In the process of moving the neutral point detecting magnet 2 relative to the Hall IC 3 in the order shown in (a) to (d), in the process of moving the neutral point detecting magnet 2 perpendicular to the magnetic pole surface of the neutral point detecting magnet 2 by the Hall IC 3. When detecting the magnetic field component (magnetic field line 7), when the Hall IC 3 is located directly above the magnetic pole of the neutral point detection magnet 2, the magnetic field distribution (Hall IC 3) (A magnetic field detected by the sensor).

On the other hand, at a position slightly away from the magnetic pole tip of the neutral point detection magnet 2, the magnetic component detected by the Hall IC 3 does not become strong because the horizontal component of the magnetic field is mainly attracted to the magnetic piece 6.

As a result, the magnetic material pieces 6 cause the holes I
The vertical component of the magnetic field applied to C3 becomes strong when it is on the magnetic pole of the neutral point detecting magnet 2, but becomes sharply weak away from the magnetic pole end of the neutral point detecting magnet 2.

According to this effect, even if the gap from the magnet surface of the neutral point detecting magnet 2 to the sensing part of the Hall IC 3 changes, the neutral point detecting angle range does not largely change, so that the precision of the magnetic sensor including the Hall IC 3 can be improved. It is possible to realize a rotation angle detection sensor capable of detecting a rotation angle such as a steering wheel angle of a vehicle without requiring a complicated assembly.

FIGS. 4 and 5 show the configuration of a main part of another embodiment of the rotation angle detecting sensor according to the present invention. FIG. 4 is a perspective view, and FIG.

In this rotation angle detecting sensor 1A, the Hall IC described with reference to FIGS. 1 and 2 is arranged along the inner circumference of a ring magnet 8 in which N and S poles are alternately arranged by a suitably selected number over the entire circumference of the ring. The magnetic field component perpendicular to the magnetic pole surface is detected for the neutral point detection magnet 2A that is rotatably mounted. The ring magnet 8 is
Unlike the conventional rotation angle detection sensor, the ring is not magnetized in the radial direction of the ring, but is magnetized in the axial direction of the ring.

In this case, the neutral point detecting magnet 2A rotatably mounted along the inner circumference of the ring magnet 8 in which the N and S poles are alternately arranged by a suitably selected number over the entire circumference of the ring is targeted. When a magnetic field component perpendicular to the magnetic pole surface is detected by the Hall IC, even if the gap from the magnet surface of the neutral point detecting magnet 2A to the sensing part of the Hall IC changes, the neutral point detection angle range does not greatly change. Similarly to the rotation angle detection sensor 1 shown in FIGS. 1 and 2, a rotation angle detection sensor capable of detecting a rotation angle such as a steering wheel angle of a vehicle without precise assembly can be realized.

Since the magnetic field of the ring magnet 8 magnetized in the axial direction of the ring can be detected by the rotation detection sensor 9, the arrangement of the magnetic sensor including the Hall IC for the ring magnet 8 is different from that of the conventional rotation angle detection sensor. Even if they are the same, a rotation angle such as a steering wheel angle of the vehicle can be detected.

As described above, in the case of the rotation angle detecting sensor according to the present invention, the magnetic piece 6 having substantially the same size as the Hall IC 3 is fixed to the back side of the Hall IC 3 of the circuit board 5 on which the Hall IC 3 is mounted. Since the angle range as the neutral point can be detected accurately, for example, even for a ring magnet that is magnetized without using a magnetized yoke with a complicated structure, the neutral point detection angle range is between the magnet and the Hall IC. Gap dependency can be improved.

FIG. 6 is a characteristic curve diagram showing the result of simulating the neutral point detection angle range with and without a magnetic piece on the back side of the Hall IC 3 of the circuit board 5 on which the Hall IC 3 is mounted. Here, the magnetic field analysis software calculates the magnetic field distribution by the neutral point detecting magnet by changing the distance and position (movement by rotation) from the magnetic piece, and calculates the angle (position) of the magnetic field intensity at which the Hall IC turns on and off. ).

As can be seen from this characteristic curve, the hole I
In the case where there is no magnetic piece on the back side of the Hall IC of the circuit board to which C is attached, the neutral point detection angle range (de) increases as the gap (mm) increases as compared with the case where there is a magnetic piece.
It can be seen that the change in g) is small. In other words, when there is a magnetic piece on the back side of the Hall IC on the circuit board on which the Hall IC is mounted, the change in the neutral point detection angle range (deg) is reduced even if the gap (mm) is separated. As a result, the sensitivity at the time of detecting the neutral point, which is a reference for detecting the rotation angle, can be improved, and the gap characteristics of the neutral point detection angle range can be stabilized.

[0039]

As described above, according to the present invention, since the magnetic piece is fixedly arranged on the back side of the Hall IC of the circuit board on which the Hall IC is mounted, the neutral point serving as a reference for detecting the rotation angle is provided. Of the rotation angle detection sensor that can improve the sensitivity when detecting the rotation angle and can stabilize the gap characteristics in the neutral point detection angle range.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a schematic configuration of an embodiment of a rotation angle detection sensor according to the present invention.

FIG. 2 is a perspective view showing a schematic configuration of an embodiment of a rotation angle detection sensor according to the present invention.

FIG. 3 is a state explanatory view showing a change in a magnetic field accompanying movement of a neutral point detecting magnet in the configuration of the embodiment of the present invention.

FIG. 4 is a perspective view showing a main configuration of another embodiment of the rotation angle detection sensor according to the present invention.

FIG. 5 is a configuration explanatory view showing a main configuration of another embodiment of the rotation angle detection sensor according to the present invention.

FIG. 6 is a circuit board mounted with a Hall IC.
FIG. 9 is a characteristic curve diagram showing a result of simulating a neutral point detection angle range in a case where a magnetic material piece is present on the back side and in a case where no magnetic piece is present.

FIG. 7 is a diagram used to explain a problem at the time of detecting a neutral point in a conventional rotation angle detection sensor.

[Explanation of symbols]

 1, 1A Rotation angle detection sensor 2, 2A Neutral point detection magnet 3 Hall IC 4 Magnetic field detection unit 5 Circuit board 6 Magnetic piece 7 Magnetic field line 8 Ring magnet 9 Rotation detection sensor

Claims (3)

[Claims] In a process in which a neutral point detecting magnet is relatively moved with respect to a Hall IC, a Hall IC detects a magnetic field component perpendicular to a magnetic pole surface of the neutral point detecting magnet. A rotation angle detection sensor for detecting a rotation angle of a rotating body based on a neutral point angle detection range of a magnetic field strength to be turned off, wherein a Hall IC on a circuit board on which the Hall IC is mounted
A rotation angle detecting sensor, wherein a magnetic piece having substantially the same size as the Hall IC is fixedly arranged on the back side of the mounting position. 2. The rotation angle detection sensor according to claim 1, wherein the Hall IC rotates along an inner circumference of a ring magnet in which N and S poles are alternately arranged by a suitably selected number over the entire circumference of the ring. A rotation angle detection sensor for detecting a magnetic field component perpendicular to a magnetic pole surface for a neutral point detection magnet as assembled as possible. 3. The rotation angle detection sensor according to claim 2, wherein the ring magnet is magnetized in an axial direction of the ring.
A rotation angle detection sensor, characterized in that: