JP2003004412A - Rotary angle detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotary angle detector which can stably detect rotary angle, while restraining influence of disturbances. SOLUTION: This rotary angle detector 11 is provided with a magnet 13, having a through-hole 13 and a magnetic resistance sensor 15, to detect the direction of magnetic flux Z of the magnet 12. the magnetic resistance sensor 15 is arranged between the outer circumference of a shaft 14 and the inner circumferential surface of the through-hole 13. The magnetic resistance sensor 15 detects relative rotational angle between the magnet 12 and magnetic resistance sensor 15. The magnetic flux Z is detected, in a state with its being enclosed by a wraparound magnetic flux G, by the magnetic resistance sensor 15. Therefore, even if there is a disturbed magnetic field adjacent to the rotation angle detector 11, the magnetic flux Z is unlikely to be influenced by the disturbing magnetic field, when compared with the wraparound magnetic flux G, and the direction of magnetic flux is stabilized. As a result, influence due to the disturbance can be prevented, permitting stable detection of rotation angle.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotation angle detecting device for detecting a rotation angle.

[0002]

2. Description of the Related Art As shown in FIGS. 9 and 10, the applicant has already proposed a rotation angle detecting device for detecting a rotation angle.
A shift lever rotation angle detecting device 81 is proposed (Japanese Patent Application No. 2000-124336).

The rotation angle detecting device 81 includes a ring-shaped magnet 82 magnetized in a fixed direction.
The magnet 82 has a through hole 83, and a shaft 84 that rotates with the operation of a shift lever (not shown) is fitted in the through hole 83 in an inserted state. And
The shift lever and magnet 82 are adapted to rotate together via a shaft 84. Magnet 82
Is magnetized so that its magnetic flux is oriented in the horizontal direction (left and right direction in FIG. 10).

A magnetic resistance sensor 85 for detecting the direction of the magnetic flux is provided above the ring portion of the magnet 82, and the magnetic resistance sensor 85 detects the direction of the magnetic flux generated from the magnet 82 above the magnet 82. It is like this. The magnetic flux located around (above and below) the magnet as shown in FIG. The magnetoresistive sensor 85 for detecting the wraparound magnetic flux is fixed to a fixing member (not shown).
When the magnet 82 rotates as the shift lever is operated, an output value corresponding to the rotation is output from the magnetic resistance sensor 85, and the rotation angle of the shaft 84 is detected from the output value. ing.

As another conventional example, a rotation angle detecting device shown in FIGS. 11 and 12 is known. In this rotation angle detection device 91, a ring-shaped magnet (magnet plate) 92
Are vertically magnetized in the thickness direction along the central axis m. Then, on the central axis m, a magnetoresistive sensor 93 is arranged above the magnet 92, and either the magnet 92 or the magnetoresistive sensor 93 is placed on the central axis m.
By rotating around, the rotation angle of a shift lever (not shown) linked to either the magnet 92 or the magnetic resistance sensor 93 is detected.

[0006]

However, in the former rotation angle detecting device 81, the magnetoresistive sensor 85 detects the direction of the wraparound magnetic flux generated above the magnet 82 from the magnet 82. for that reason,
If there is a disturbance magnetic field near the rotation angle detection device 81, the direction of the wraparound magnetic flux generated above the magnet 82 tends to change, and as a result, accurate rotation angle detection may not be possible.

Also in the latter rotation angle detection device 91, the magnetoresistive sensor 93 is adapted to detect the direction of the wraparound magnetic flux generated from the magnet 92 above the magnet. Therefore, when there is a disturbance magnetic field in the vicinity of the rotation angle detection device 91, the direction of the wraparound magnetic flux generated above the magnet 92 is likely to change, and as a result, there is a problem that accurate rotation angle detection cannot be performed. It was

Therefore, the present invention has been made in view of the above-mentioned circumstances, and an object thereof is to provide a rotation angle detecting device capable of suppressing the influence of disturbance and performing stable rotation angle detection. .

[0009]

In order to achieve the above object, the invention according to claim 1 is a magnet magnetized in a fixed direction and having a through hole, and a magnet for detecting the direction of the magnetic flux of the magnet. A resistance sensor is provided, and by rotating the magnet and the magnetoresistive sensor relative to each other, the magnetoresistive sensor detects the amount of movement of the detection target linked to either the magnet or the magnetoresistive sensor. In the rotation angle detecting device, the magnet is magnetized so that the magnetic flux is directed along the front and back surfaces of the magnet, the magnetoresistive sensor is arranged in the through hole, and the magnetoresistive sensor is the magnet. The point is to detect the magnetic flux emitted from the inner peripheral surface of the through hole.

According to a second aspect of the present invention, in the first aspect of the present invention, the direction of the magnetic flux emitted from the inner peripheral surface is changed in the through hole of the magnet, and the changed magnetic flux is stabilized. The body is inserted, and the gist is that the magnetoresistive sensor is arranged between the outer periphery of the magnetic body and the inner peripheral surface of the through hole.

According to a third aspect of the present invention, in the second aspect, one of the magnet and the magnetoresistive sensor is connected to the magnetic body and rotates together with the magnetic body.

According to a fourth aspect of the invention, in the third aspect, the magnet and the center of the magnetic body are arranged on the same center. (Operation) Therefore, in the invention described in claim 1, the magnetoresistive sensor detects the relative angle with the magnet by detecting the magnetic flux emitted from the inner peripheral surface of the through hole. Then, the rotation angle of the detected object linked to either the magnet or the magnetoresistive sensor is detected. By the way, the magnetic flux emitted from the inner peripheral surface of the through hole is blocked by the wraparound magnetic flux emitted from other than the inner peripheral surface of the through hole. for that reason,
The magnetic flux emitted from the inner peripheral surface of the through hole is less susceptible to the influence of disturbance than the wraparound magnetic flux, and the direction of the magnetic flux is stable. As a result, the rotation angle detection device of the present invention can perform stable detection as compared with the rotation angle detection device that detects the rotation angle of the detection target by the sneak flux.

According to the invention described in claim 2, in addition to the operation described in claim 1, the direction of the magnetic flux emitted from the inner peripheral surface of the magnet is changed by the magnetic body, and the magnetic flux whose direction is changed is changed. Is stable. The magnetoresistive sensor detects a magnetic flux whose direction is changed by a magnetic body. Then, the sine wave due to the output voltage of the magnetoresistive sensor can be distorted, and the linear portion of the sine wave that is the detection range becomes longer. As a result, the detection range of the magnetoresistive sensor is increased.

In the present specification, a magnetic substance means a ferromagnetic substance, and a non-magnetic substance means a substance having no magnetism. In the invention described in claim 3, claim 2
In addition to the operation described in (1), either the magnet or the magnetoresistive sensor is connected to the magnetic body and is rotated together with the magnetic body to detect the relative rotation angle between the magnet and the magnetoresistive sensor. As a result, the rotation angle of the magnetic body is detected.

According to the invention described in claim 4, in addition to the function described in claim 3, the magnet and the magnetic body are concentrically rotated.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION (First Embodiment) A first embodiment in which the present invention is embodied in a rotation angle detection device for detecting the position of a shift lever provided in an automobile will be described in detail with reference to the drawings.

As shown in FIGS. 1 and 2, the rotation angle detection device 11 includes a ring-shaped magnet 12 magnetized in a fixed direction. A shaft 14 that is rotated by a rotation operation of a shift lever (not shown) is inserted into a circular through hole 13 formed in a central portion of the magnet 12. The shift lever corresponds to the detected object. The shaft 14 and the magnet 12 are connected by a connecting body (not shown), and the shaft 14 and the magnet 12 are arranged so that their centers are the same.

The shift lever and the magnet 12 are
It is configured to rotate together via the shaft 14 and the connecting body. The shaft 14 is made of iron, and the shaft 14 corresponds to a magnetic body. The magnet 12 is
The magnetic flux is magnetized so as to be directed in the horizontal direction (left-right direction in FIG. 2). In other words, the magnet 12
Is magnetized so that the wraparound magnetic flux G is directed in a direction along both front and back surfaces.

FIG. 2 is a diagram schematically showing the positional relationship between the N pole and the S pole magnetized in the magnet 12, and as shown in the figure, the magnet 12 is arranged along the rotation center thereof. It has an extending ring-shaped first magnetic pole portion 12a. Half of the first magnetic pole portion 12a in the circumferential direction is magnetized to the N pole, and the other half is magnetized to the S pole.
The first magnetic pole portion 1 around the rotation center of the magnet 12.
A portion located outside of 2a is a second magnetic pole portion 12b having a ring shape. That is, the first magnetic pole portion 12a is arranged inside the magnet 12, and the second magnetic pole portion 12b is arranged outside.

Half of the second magnetic pole portion 12b in the circumferential direction is magnetized to the S pole, and the other half is magnetized to the N pole. The poles magnetized in the second magnetic pole portion 12b are opposite to those magnetized in the first magnetic pole portion 12a. Specifically, the outside of the N pole portion of the first magnetic pole portion 12a is the S pole of the second magnetic pole portion 12b. The outside of the S pole portion of the first magnetic pole portion 12a is the N pole of the second magnetic pole portion 12b. Due to the positional relationship of the poles described above, the wraparound magnetic flux G in the magnetic field generated around the magnet 12 is directed in the direction along both side surfaces of the magnet 12 (in FIG. 2, the upper and lower surfaces of the magnet 12 are indicated by arrows). Direction).

Further, as shown in FIG. 4, a magnetic flux Z from the N pole to the S pole appears in the through hole 13 of the magnet 12. The magnetic flux Z corresponds to "a magnetic flux emitted from the inner peripheral surface of the through hole". As shown in FIG. 3, a part of the magnetic flux Z (particularly, the N pole in the first magnetic pole portion 12a, or the second magnetic pole portion 12a).
(Refers to a magnetic flux other than the magnetic flux generated in the central portion of the S pole in the magnetic pole portion 12b) is curved so as to be slightly attracted to the shaft 14 when going from the N pole to the S pole.

As shown in FIGS. 1 and 2, the shaft 14
A magnetoresistive sensor 15 is arranged between the outer periphery of the magnetic reed and the inner peripheral surface of the through hole 13, and the magnetoresistive sensor 15 is fixed to a fixing member (not shown). The magnetoresistive sensor 15
Is configured to detect the direction of the magnetic flux Z.
As shown in FIG. 2, the magnetoresistive sensor 15 is arranged substantially in the center of the magnet 12 in the central axis O direction of the shaft 14. The central axis O direction corresponds to the through hole forming direction. Then, in the magnetoresistive sensor 15,
The magnetic flux Z of the magnet 12 is arranged so as to interlink.

As shown in FIG. 6, the magnetoresistive sensor 15
Has a circuit configuration in which four resistance elements R1, R2, R3 and R4 are connected to a full bridge. Resistance element R1
Each of R4 is made of a ferromagnetic material such as Ni-Co. As shown in FIGS. 1 and 2, the resistance elements R1 to R4 are arranged on the shaft 14 side of the magnetoresistive sensor 15. As shown in FIG. 1, one resistance element R2, R3
And the other resistance elements R1 and R4 are respectively arranged at an angle of 45 ° with respect to the surface M1 along the radial direction of the shaft 14. In addition, as shown in FIG. 2, one of the resistance elements R2 and R3 and the other of the resistance elements R1 and R4 are 4 with respect to the plane M2 orthogonal to the central axis O of the shaft 14.
They are arranged at an inclination of 5 °.

In FIG. 1, the N of the first magnetic pole portion 12a is
The rotation angle is set to 0 ° when the magnetoresistive sensor 15 is positioned closest to the pole or the central portion of the S pole of the second magnetic pole portion 12b. And this rotation angle 0
It is set so that the rotation angle can be detected within a range of ± 50 ° centering on the degree. That is, in this embodiment, the detection range is set to about 100 °.

When the magnet 12 rotates a predetermined angle with respect to the magnetoresistive sensor 15 as the shift lever is rotated, the direction of the magnetic flux Z interlinking with the magnetoresistive sensor 15 changes. In response to this change, the magnetoresistive sensor 15 outputs the output voltage ΔV in an analog manner. This output voltage ΔV is applied to one of the resistance elements R1 and R1.
2 and the potential difference between the other resistance elements R3 and R4.

As shown in FIG. 5, the output voltage ΔV is a sine wave having one cycle of 180 °, and the linear portion of this sine wave is the detection range of the rotation angle of the shift lever. This sine wave is distorted because a part of the magnetic flux Z is curved so as to be attracted to the shaft 14 (see FIG. 3), and the linear portion of the sine wave that is the detection range is compared with the undistorted sine wave. Have been long. In addition, "P" shown in FIG. 5 indicates the parking position of the shift lever, "R" indicates the rear drive position, "N" indicates the neutral position, and "D" indicates the drive position.

Next, the operation of the rotation angle detecting device 11 constructed as in the first embodiment will be described. When a shift lever (not shown) is operated, the shaft 14 and the magnet 12 rotate about the central axis O within a range of about 100 °. Then, the rotation angle causes the magnetoresistive sensor 15 to output the output voltage ΔV corresponding to the rotation angle. The rotation angle of the shaft 14 and the magnet 12 with respect to the magnetoresistive sensor 15 is detected by the output voltage ΔV.

The magnetoresistive sensor 15 is configured to detect the magnetic flux Z emitted from the inner peripheral surface of the through hole 13 of the magnet 12. By the way, in the magnet 12, the magnetic flux G wraps around the both side surfaces of the magnet 12 and appears. Since the magnetic flux Z is blocked by the wraparound magnetic flux G, even if there is a disturbance magnetic field (disturbance) in the vicinity of the rotation angle detection device 11, it is less affected by the disturbance magnetic field than the wraparound magnetic flux G. . Therefore, the direction of the magnetic flux Z is stable even if there is a disturbance magnetic field in the vicinity of the rotation angle detection device 11.

Further, the magnetoresistive sensor 15 is arranged substantially at the center of the magnet 12 in the central axis O direction of the shaft 14. Therefore, the magnetic flux Z detected by the magnetoresistive sensor 15 is also blocked by the magnetic flux Z located above and below the magnetoresistive sensor 15. Therefore, the magnetic flux Z detected by the magnetoresistive sensor 15 is much less susceptible to the disturbance magnetic field. As a result, the rotation angle detection device 11 can perform stable detection as compared with the rotation angle detection devices 81 and 91 of the related art.

Therefore, according to the rotation angle detecting device 11 of the first embodiment, the following effects can be obtained. (1) In the present embodiment, the rotation angle detection device 11 is magnetized in a fixed direction and has a through hole 13.
2 and a magnetoresistive sensor 15 for detecting the direction of the magnetic flux Z of the magnet 12. The magnetoresistive sensor 15 is arranged between the outer periphery of the shaft 14 and the inner peripheral surface of the through hole 13.
Then, by detecting the relative rotation angle between the magnet 12 and the magnetic resistance sensor 15 by the magnetic resistance sensor 15,
The position (rotation angle) of the shift lever is detected.

Then, the magnetic flux Z is detected by the magnetoresistive sensor 15 while being blocked by the sneak flux G. Therefore, even if there is a disturbance magnetic field in the vicinity of the rotation angle detection device 11, the magnetic flux Z is less likely to be affected by the disturbance magnetic field than the sneak flux G, and the direction of the magnetic flux Z is stable. Therefore, the rotation angle detection device 11 can suppress the influence of disturbance and perform stable rotation angle detection as compared with the rotation angle detection devices 81 and 91.

(2) In this embodiment, the magnetic flux Z generated from the inner peripheral surface of the magnet 12 is inserted into the through hole 13 of the magnet 12.
And a shaft 14 for stabilizing the attracted magnetic flux Z. And the magnetoresistive sensor 1
5 is configured to detect the magnetic flux Z whose direction is slightly changed by the shaft 14. Then, the magnetoresistive sensor 15
The sine wave of the output voltage ΔV can be distorted, and the linear portion of the sine wave that is the detection range becomes longer. As a result, the detection range of the magnetoresistive sensor 15 can be made larger than that of an undistorted sine wave. Further, in this embodiment, the detection range can be set to about 100 °.

(3) In this embodiment, the magnet 12 and the shaft 14 are connected to each other via a connecting body (not shown).
Then, the magnet 12 and the shaft 14 are configured to rotate together. Further, the magnetoresistive sensor 15 was fixed to a fixing member (not shown). When the shaft 14 is rotated in accordance with the rotation operation of the shift lever, the magnet 1
2 also rotates together. Then, the magnet 12 moves relative to the magnetoresistive sensor 15, so that the shaft 1
4 and the magnetic resistance sensor 15 can detect the relative rotation angle.

(4) In this embodiment, the centers of the magnet 12 and the shaft 14 are arranged at the same center. for that reason,
The magnet 12 does not cause eccentricity with respect to the shaft 14, and the magnetic flux Z applied to the magnetoresistive sensor 15 does not become irregular. Therefore, the magnetoresistive sensor 15 can satisfactorily detect the direction of the magnetic flux Z.

(5) In this embodiment, the magnetoresistive sensor 1
The magnet No. 5 is arranged substantially in the center of the magnet 12 in the central axis O direction of the shaft 14. Therefore, the magnetic flux Z detected by the magnetoresistive sensor 15 is also blocked by the magnetic flux Z located above and below the magnetoresistive sensor 15. Therefore, the magnetic flux Z detected by the magnetoresistive sensor 15 is much less susceptible to the disturbance magnetic field. Therefore, the rotation angle detection device 11 is different from the rotation angle detection devices 81 and 91 of the prior art.
Can perform more stable detection.

(6) Magnetoresistive sensor 15 of this embodiment
Has a circuit configuration in which four resistance elements R1, R2, R3 and R4 are connected to a full bridge. Therefore, the direction of the magnetic flux can be reliably detected despite the simple configuration.

(Second Embodiment) A second embodiment in which the present invention is embodied in a rotation angle detecting device for detecting the position of a shift lever provided in an automobile will be described in detail with reference to the drawings. In addition, the rotation angle detection device 21 of the second embodiment.
Is a modification of the first embodiment.
The same components as those in the embodiment are designated by the same reference numerals,
Detailed description thereof will be omitted, and only different points will be described.

The rotation angle detection device 21 of this embodiment corresponds to the rotation angle detection device 11 in which the shaft 14 is replaced with a shaft 22 made of aluminum or the like. The shaft 22 is a non-magnetic material.

Therefore, since the shaft 22 which is a non-magnetic material does not attract the magnetic flux Z, the magnetic flux Z goes straight from the N pole to the S pole as shown in FIG. In FIG.
The rotation angle detection device 21 has a rotation angle of 0 ° as a center ±
The rotation angle can be detected within the range of 30 °. That is, in this embodiment, the detection range is set to about 60 °.

As shown in FIG. 8, the output voltage ΔV is a sine wave having one cycle of 180 °, and the linear portion of this sine wave is the detection range of the rotation angle of the shift lever. Since this sine wave is a sine wave with no distortion, the detection range is shorter than the detection range of the rotation angle detection device 11.
As shown in FIG. 8, the parking position (P), the rear drive position (R), the neutral position (N), and the drive position (D) of the shift lever are provided within the detection range of about 60 °. There is.

Next, since the rotation angle detecting device 21 configured as in the second embodiment has substantially the same action as the rotation angle detecting device 11, only different actions will be described.
The rotation angle detection device 21 includes a shaft 22 and a magnet 1.
2 rotates about the central axis O within a range of about 60 °. Further, the magnetic resistance sensor 15 of the rotation angle detection device 21 is
A magnetic flux Z that linearly goes from the pole to the S pole is detected.

Therefore, according to the rotation angle detecting device 21 of the second embodiment, (1) in the first embodiment,
The same effects as (3) and (4) to (6) are obtained. (Other Embodiments) The above embodiments may be embodied by being changed to other embodiments as described below.

In the first and second embodiments, the magnet 12 is ring-shaped and has a circular through hole 1.
Had three. The shape of the magnet 12 is not limited to this, and the magnet 12 may have a triangular, square, or irregular shape as long as it has the circular through hole 13.

In the first embodiment, the magnetoresistive sensor 15 is fixed to the fixing member (not shown), and the shift lever (not shown) and the magnet 12 are rotated together via the shaft 14 and the connecting body. I was making up. Not limited to this, the magnet 12 may be fixed to a fixing member, and the shift lever (not shown) and the magnetoresistive sensor 15 may be configured to rotate together via the shaft 14 and the coupling body. Even with this configuration, the same effect as that of the first embodiment can be obtained. Further, such changes may be embodied in the second embodiment. Even with this configuration, the same effect as that of the second embodiment can be obtained.

In the second embodiment, the shaft 22 is provided, but it may be omitted. In this case, magnet 1
2 is configured to rotate with the operation of a shift lever (not shown). Even with this structure, the same effect as that of the second embodiment can be obtained.

In the first and second embodiments, the magnetoresistive sensor 15 has the magnet 12 in the central axis O direction.
Was arranged in the approximate center (in the thickness direction of the magnet 12). Not limited to this, the magnetoresistive sensor 15 may be arranged so as to be slightly above or slightly below the magnetoresistive sensor 15 of the first and second embodiments. In short,
The magnetoresistive sensor 15 may be arranged so as to detect the magnetic flux Z emitted from the inner peripheral surface of the through hole 13 of the magnet 12. With this configuration, the magnetic flux Z detected by the magnetoresistive sensor 15 becomes the magnetic flux Z on the side of the sneak flux G compared to the magnetic resistance sensor 15 of the first and second embodiments. Therefore, the rotation angle detecting device is the same as the rotation angle detecting device 1.
Although it is more susceptible to the disturbance magnetic field than Nos. 1 and 21, it is possible to suppress the influence of the disturbance magnetic field and to perform stable rotation angle detection as compared with the rotation angle detecting devices 81 and 91 described in the related art. .

Although the shaft 14 is made of iron in the first embodiment, it may be made of a magnetic metal such as nickel or cobalt. In the second embodiment, the shaft 22 is made of aluminum, but it may be made of a non-magnetic substance such as stainless steel or synthetic resin.

In the first and second embodiments, the magnet 12 is composed of the first magnetic pole portion 12a and the second magnetic pole portion 12b, but the first magnetic pole without the second magnetic pole portion 12b. The portion 12a may be the magnet 12. Even with this structure, substantially the same effects as those of the first and second embodiments can be obtained.

Next, technical ideas that can be understood from the above-described embodiments and other embodiments will be described below together with their effects. (A) The rotation angle detection device according to any one of claims 1 to 4, wherein the magnetoresistive sensor is provided at a substantially central portion in the through hole forming direction. With this configuration, the magnetic flux emitted from the substantially central portion of the inner peripheral surface of the through hole in the through hole forming direction is barriered by the magnetic flux on both sides of the through hole forming direction, so that the magnetic flux is less likely to be affected by disturbance and the direction of the magnetic flux is Stabilize. Therefore, the magnetoresistive sensor can detect the direction of the magnetic flux more accurately.

(B) The magnetoresistive sensor includes a plurality of resistance elements connected to a full bridge, and each resistance element is made of a ferromagnetic material. The rotation angle detection device according to any one of (a). With this configuration, the direction of the magnetic flux can be reliably detected despite the simple configuration.

[0051]

As described in detail above, according to the invention described in claims 1 to 4, it is possible to suppress the influence of disturbance and perform stable rotation angle detection.

According to the second aspect of the invention, the detection range of the rotation angle detecting device can be increased. According to the invention described in claim 3, it is possible to detect the relative rotation angle between one of the magnet and the magnetoresistive sensor and the magnetic body.

According to the fourth aspect of the present invention, the magnet does not cause eccentricity with respect to the magnetic body, and the magnetoresistive sensor can detect the direction of the magnetic flux in a good condition.

[Brief description of drawings]

FIG. 1 is a front view of a rotation angle detection device according to a first embodiment.

FIG. 2 is a side partial cross-sectional view of the rotation angle detection device in the first embodiment.

FIG. 3 is an explanatory diagram showing a direction of a magnetic flux Z in the first embodiment.

FIG. 4 is an explanatory view showing a positional relationship between a magnetic flux Z and a sneak flux G in the first embodiment.

FIG. 5 is an explanatory diagram showing electrical characteristics of an output voltage of the magnetoresistive sensor according to the first embodiment.

FIG. 6 is a circuit diagram showing a circuit configuration of a magnetoresistive sensor.

FIG. 7 is a front view of a rotation angle detection device according to a second embodiment.

FIG. 8 is an explanatory diagram showing electrical characteristics of an output voltage of the magnetoresistive sensor according to the second embodiment.

FIG. 9 is a front view of a rotation angle detection device 81 in the related art.

FIG. 10 is a partial cross-sectional side view of a rotation angle detection device 81 according to a conventional technique.

FIG. 11 is a front view of a rotation angle detection device 91 according to a conventional technique.

FIG. 12 is a side partial cross-sectional view of a rotation angle detection device 91 in the related art.

[Explanation of symbols]

11, 21 ... Rotation angle detection device, 12 ... Magnet, 1
3 ... Through hole, 14 ... Shaft as magnetic material, 15 ... Magnetoresistive sensor, Z ... Magnetic flux as "magnetic flux emitted from inner peripheral surface of through hole".

Claims (4)

[Claims] 1. A magnet, which is magnetized in a fixed direction and has a through hole, and a magnetoresistive sensor for detecting the direction of the magnetic flux of the magnet, wherein the magnet and the magnetoresistive sensor are relatively rotated. Thus, in the rotation angle detection device for detecting the movement amount of the detected object linked to either the magnet or the magnetic resistance sensor by the magnetic resistance sensor, the magnetic flux is directed in the direction along the front and back surfaces of the magnet. The magnet is magnetized, the magnetoresistive sensor is arranged in the through hole, and the magnetoresistive sensor detects a magnetic flux emitted from an inner peripheral surface of the through hole of the magnet. Detection device. 2. A magnetic body that changes the direction of the magnetic flux emitted from the inner peripheral surface and stabilizes the magnetic flux whose direction is changed is inserted into the through hole of the magnet. The magnetic body is arranged between the outer periphery of the magnetic body and the inner peripheral surface of the through hole.
The rotation angle detection device described in. 3. The rotation angle detecting device according to claim 2, wherein one of the magnet and the magnetoresistive sensor is connected to the magnetic body and rotates together with the magnetic body. 4. The rotation angle detecting device according to claim 3, wherein the magnet and the center of the magnetic body are arranged on the same center.