JP2017090073A - Non-contact type rotation angle detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a non-contact type rotation angle detector that reduces errors of output values due to the misalignment between a permanent magnet and a magnetic sensor shaft and that can increase an acceptable range of the separation distance between the magnetic sensor and the permanent magnet in an axis direction.SOLUTION: The non-contact type rotation angle detector includes: a permanent magnet 32 provided to an end part of an output shaft 6 as a rotation shaft of a measurement target so that the N pole and the S pole are located in a radial direction; and a flux azimuth detection type magnetic sensor 31 arranged to face the permanent magnet 32 with a space in between in an axis direction of the output shaft 6, the permanent magnet 32 being formed in the shape of a cylinder having a hollow 32a and being fixed to the end part of the output shaft 6.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a non-contact type rotational angle detection device that detects a rotational angle of a rotating body in a non-contact manner using a magnet and a magnetic sensor. For example, a shift range selected by a shift lever is transmitted via an electrical signal. This is applied to the detection of the rotation angle of the output shaft of a range switching device equipped with a so-called shift-by-wire system.

  2. Description of the Related Art Conventionally, a rotation angle detection device using a magnet and a magnetic sensor is known as means for detecting a rotation angle without contact. For example, Patent Document 1 discloses a technique in which a rotation angle detection device is incorporated in an intake control device in order to detect a rotation angle of a shaft of a throttle valve of an intake control device for an engine. FIG. 6 schematically illustrates a non-contact type rotational angle detection device disclosed in Patent Document 1. FIG. 7 is a plan view as seen from the arrow BB in FIG.

As shown in FIG. 6, a permanent magnet 52 is provided at the end of the shaft 51 to be measured so that the north and south poles are in the radial direction, and is separated from the permanent magnet 52 by a predetermined distance in parallel. A magnetic sensor 54 having a sensor detection unit 54a made of a magnetoresistive element is provided on the cover 53 side of the housing. By detecting a change in the direction of the magnetic flux 55 of the permanent magnet 52 by the magnetic sensor 54, the rotation angle of the shaft 51 is detected in a non-contact manner.
In FIG. 6, for the following description, a deviation between the center of the detection unit of the magnetic sensor 54 and the rotation center axis of the shaft 51 on the detected side, that is, the magnet center, is shown as an axis deviation R ₂ . Further, the magnetic flux 55 is indicated by a broken line, and FIG. 7 shows the width 55a of the magnetic flux stabilization region.

Japanese Patent Laying-Open No. 2005-54654 (page 3-4, FIG. 3)

  Magnetic flux direction detection type magnetic sensor detects a change in magnetic flux direction of the magnet provided on the detected side and outputs a signal, but it detects the center of the magnetic sensor and the rotation center axis of the detected side, that is, the magnet center If there is a deviation, an error occurs in the sensor output value, so it is necessary to suppress the axial deviation between the magnetic sensor and the magnet as much as possible. However, a certain degree of shaft misalignment must be allowed due to variations in component dimensions, bearing backlash, etc. Therefore, it is desirable to have a configuration that minimizes the influence on the sensor output even when shaft misalignment occurs.

In the conventional non-contact type rotational angle detection device as shown in Patent Document 1, a block-shaped solid permanent magnet is employed as the magnet provided on the detected side. Thus, enlarged in order to reduce the output value error due to axial misalignment R ₂ of the permanent magnet 52 and the magnetic sensor 54, if Grow width 55a of the magnetic flux stable region of the axial orthogonal direction, the outer shape of the permanent magnet 52 There is a need to. However, since the permanent magnet 52 has a solid shape, if the outer shape is enlarged, the volume of the magnet is greatly increased, resulting in a problem that the cost of the parts increases.

In addition, when a high-sensitivity GMR (Giant Magneto Resistive effect) sensor is used as the magnetic sensor 54, if a magnetic flux of a certain value or more is applied, the sensor is damaged. _When the outer shape of the permanent magnet 52 is expanded in order to cover ₂ , there is a problem that the magnetic flux inevitably increases and exceeds the upper limit value.
Further, according to the outline expansion, change increases the magnetic flux density (gradient change in the magnetic flux density is increased) relative to the axial direction of the change in the distance L ₂ between the magnetic sensor 54 and the permanent magnet 52 for the variation in the mounting dimensions, etc. allowable range of the distance change of the distance L ₂ becomes narrow, component accuracy, must be strictly controlled assembly accuracy caused.

  The present invention has been made to solve the above-described problems, and reduces the influence on the output value due to the axial misalignment between the permanent magnet and the magnetic sensor with a simple configuration. It is an object of the present invention to provide a non-contact type rotational angle detection device capable of expanding the allowable range of distance change between a sensor and a permanent magnet.

  A non-contact rotation angle detection device according to the present invention includes a permanent magnet provided at a shaft end of a rotation shaft to be measured so that the N pole and the S pole are positioned in the radial direction of the rotation shaft, and the permanent magnet On the other hand, a magnetic flux direction detection type magnetic sensor arranged opposite to and spaced apart in the axial direction of the rotating shaft, the permanent magnet is formed in a cylindrical shape having a hollow portion and is fixed to the shaft end portion of the rotating shaft. It is what.

  According to the non-contact rotation angle detection device of the present invention, the permanent magnet provided at the shaft end portion of the rotation shaft to be measured is opposed to the magnetic sensor and is formed in a cylindrical shape having a hollow portion and rotates. Since it is fixed to the shaft end portion of the shaft, the magnetic flux stable region in the orthogonal direction extends on the axis of the rotating shaft, and the magnetic flux can be prevented from increasing more than necessary. Furthermore, it is possible to make the change gradient of the magnetic flux gradual with respect to the axial distance change. For this reason, even if an axial misalignment between the axis of the rotating shaft and the center of the magnetic sensor occurs due to variations in component dimensions, bearing backlash, etc., the influence on the sensor output value due to the axial misalignment can be reduced. The allowable range of the change in the distance between the axial magnetic sensor and the permanent magnet is widened, and dimensional management becomes easy.

It is side surface sectional drawing which shows the range switching apparatus using the non-contact-type rotation angle detection apparatus of this invention. It is side surface sectional drawing which shows the non-contact-type rotation angle detection apparatus by Embodiment 1 of this invention. It is a top view of the permanent magnet part of the arrow AA direction in FIG. It is explanatory drawing explaining the gradient of the magnetic flux density of the separation direction between a magnetic sensor and a permanent magnet, and the dispersion | variation tolerance range of separation distance. It is a top view of the permanent magnet part of the non-contact-type rotation angle detection apparatus by Embodiment 2 of this invention. It is side surface sectional drawing which shows the conventional non-contact-type rotation angle detection apparatus. It is a top view of the permanent magnet part of the arrow BB direction in FIG.

Embodiment 1 FIG.
Hereinafter, a non-contact rotation angle detection device according to Embodiment 1 of the present invention will be described with reference to the drawings. The non-contact rotation angle detection device is used, for example, in a range switching device attached to an automatic transmission mounted on a vehicle. The range switching device rotates a shift shaft on the automatic transmission side based on a shift signal (electrical signal) from a shift lever (range selection means) selected by a driver, so that a predetermined shift range (P, R, N, D) are set.
Therefore, a non-contact type rotation angle detection device will be described below by taking as an example a case where it is applied to this range switching device.

FIG. 1 is a side sectional view showing a range switching device to which the non-contact type rotational angle detecting device of the present invention is applied, and FIG. 2 is a side sectional view showing a portion of the non-contact type rotational angle detecting device in FIG. FIGS. 3A and 3B are plan views of the permanent magnet portion viewed in the direction of arrow AA in FIG.
First, the outline of the range switching device 1 will be described with reference to FIG. In FIG. 1, a range switching device 1 includes a substrate 2 that receives a control signal from an external control unit based on a shift signal from a shift lever (not shown), a motor 3 that is controlled based on the control signal, A speed reduction mechanism unit 4 connected to the motor 3, an output shaft 6 of a range switching unit 5 connected to the speed reduction mechanism unit 4, and a rotation angle detection device unit 30 are provided. In FIG. 1, for convenience, the upper side is described as the rear side, and the lower side is described as the front side.

The housing of the range switching device 1 includes a front body 7 and a rear body 8. The motor 3 accommodated therein is a brushless motor using a permanent magnet. The rotor 9 is rotatably supported, the stator 10 is disposed coaxially with the rotation center of the rotor 9, and the motor 3 The motor shaft 11 is a central axis. A front bearing 12 and a rear bearing 13 are assembled to the motor shaft 11, and each bearing is fixed to a bearing fixing portion 14 and a bearing fixing portion 15 on the body side.
The speed reduction mechanism unit 4 is coaxial with the motor shaft 11 by the revolving motion of the planetary gear 16, the planetary gear 16 that rotates in mesh with the external teeth formed on the motor shaft 11, the internal gear 17 that meshes with the planetary gear 16. Above, it is comprised with the small gearwheel 18 which rotates separately from the motor shaft 11, and the large gearwheel 19 which has the internal gear which meshes with it.

The output shaft 6 of the range switching unit 5 is fixed at the rotation center of the large gear 19. The output shaft 6 is rotatably supported on the support cylinder portion 7 a of the front body 7 of the range switching device 1 via a bearing member 20 provided on the inside thereof, and rotates together with the large gear 19. As described above, the shaft centers of the output shaft 6 and the motor shaft 11 are spaced apart, and the small gear 18 and the large gear 19 can be disposed.
The rotation of the motor 3 is transmitted to the speed reduction mechanism section 4 and the output shaft 6 of the range switching section 5 connected to the speed reduction mechanism section 4 is rotated to thereby rotate a transmission (not shown) connected to the output shaft 6. The shift shaft 21 is rotated by a predetermined angle to change the shift range.

Next, a non-contact type rotation angle detecting device 30 that detects the rotation angle of the output shaft 6 that is a main part of the present invention will be described with reference to FIGS.
One surface of the substrate 2 of the range switching device 1 is arranged to face the output shaft 6 of the range switching unit 5, and the rotation angle of the output shaft 6 is detected at a position facing the output shaft 6 of the substrate 2. A magnetic flux direction detection type magnetic sensor 31 having a sensor detection unit 31a is attached.
On the other hand, a cylindrical permanent magnet 32 having a hollow portion 32 a is provided at the shaft end portion of the output shaft 6 facing the magnetic sensor 31 with the north and south poles positioned in the radial direction of the output shaft 6. Yes. The output shaft 6 corresponds to a “rotary shaft” recited in the claims.

The hollow portion 32a of the permanent magnet 32 has a circular cross-sectional shape in a direction orthogonal to the central axis. That is, the permanent magnet 32 has a cylindrical shape. The permanent magnet 32 is attached to the output shaft 6 at the shaft end portion of the output shaft 6 by providing a convex portion 6a having a size to fit into the hollow portion 32a of the permanent magnet 32, and the convex portion 6a having a hollow portion. 32a is fitted and positioned, and the fitting portion is fixed by means such as adhesion. The magnetic sensor 31 and the permanent magnet 32 are provided in a non-contact manner at a predetermined interval.
The rotation angle detection device unit 30 is configured by the magnetic sensor 31, the permanent magnet 32, and a control unit (not shown) that controls them.

Next, referring to FIGS. 2 and 3, the operation of the non-contact rotation angle detection device of the present application will be described. In Figure 2, we have a gap in the axial direction between the center and the permanent magnet 32 of the sensor detecting portion 31a of the magnetic sensor 31 and the distance L _1. The magnetic sensor 31 is basically arranged in accordance with the axis of the output shaft 6 (= the axis of the permanent magnet 32). However, the center of the sensor detection unit 31a is determined depending on variations in component dimensions and assembly accuracy. and because it may axis of the permanent magnet 32 is shifted, and displaying the displacement as the axis deviation R _1. The magnetic flux 33 of the permanent magnet 32 is distributed from the north pole to the south pole as shown by broken lines in FIGS.
The following description will be made in comparison with FIGS. 6 and 7 of the conventional non-contact rotation angle detection device (hereinafter abbreviated as a conventional device) described in the background section.

FIG. 4 is an explanatory diagram for explaining an allowable variation range of the axial separation distances L ₁ and L ₂ between the detection unit of the magnetic sensor and the permanent magnet in FIGS. In the vicinity of the magnetic sensor, the magnitude (gradient) of the magnetic flux density with respect to the separation direction distance between the magnetic sensor and the permanent magnet is represented by a curve. The curve a is the case in FIG. 2 and the curve b is the case in FIG.
Since the magnetic sensor can appropriately detect a change in magnetic flux, the range of the minimum value and the maximum value of the magnetic flux passing through the detection unit is determined. This range is indicated as a required magnetic flux range R.

In FIG. 2, the permanent magnet 32 has a hollow portion 32 a and can be increased in outer diameter. Therefore, the sensor detection portion 31 a of the magnetic sensor 31 is perpendicular to the axis of the output shaft 6 as compared with FIG. The range of the parallel component of the magnetic flux 33 passing in the direction is relatively long and the gradient of change in the magnetic flux density changing in the separation direction is gentle as shown by the curve a in FIG. As shown in FIG. 4, the range of the parallel component of the magnetic flux 55 is narrow, and a gradient is established as shown by the curve b in FIG. For this reason, in the present invention, the variation allowable range of L ₁ with respect to the required magnetic flux range R is widened, and even if the setting range of the axial separation distance L ₁ between the magnetic sensor 31 and the permanent magnet 32 is widened, the output of the magnetic sensor 31. since little impact on, whereas it is possible to alleviate the dimensional tolerance and assembling tolerance of the components, in the conventional apparatus, since a narrow variation permissible range of L ₂ for required flux range R, the distance L ₂ range Therefore, the dimensional tolerance and assembly tolerance of parts must be tightened.

3 and 7 showing the plan views of the permanent magnet portion of FIGS. 2 and 6, in FIG. 7 showing the conventional device, the width 55a of the magnetic flux stable region passing near the center of the shaft 51 is narrow, Although not have to narrow sets the allowable range of the axial misalignment R ₂ and the center of rotation center and the magnetic sensor 54 shown in FIG. 6, FIG. 3 shows the present invention, the width 33a of the magnetic flux stable region is wide, the axial displacement since it is possible to widely set permissible range of R _1, similarly to the distance in the axial direction, it is possible to alleviate part dimensional tolerances or assembly tolerances relating to the axial displacement direction.

  In addition, a GMR sensor having excellent detection sensitivity may be used as the magnetic sensor 31. However, since the GMR sensor is damaged when a magnetic flux of a certain value or more is applied, an upper limit value of the magnetic flux is set. In the case of a solid permanent magnet as shown in FIG. 6, if the outer shape is widened in order to make the change gradient of the magnetic flux density gentle, the magnetic flux inevitably increases, and there is a problem that the upper limit value of the GMR sensor is exceeded. In the present invention, since the change gradient of the magnetic flux in the axial direction is gentler than that of the conventional device as described above, it is possible to suppress the deviation from the required magnetic flux range R. Therefore, the GMR sensor can be easily applied as the magnetic sensor 31. Thus, a highly sensitive non-contact rotation angle detection device can be easily provided.

In the above description, the axis deviation has been described in the case of deviation in the direction parallel to the magnetic flux, but it is effective for the axis deviation in the direction orthogonal thereto because the magnetic flux stable region is wider than that of the conventional device. .
Further, the permanent magnet 32 is magnetized with N and S poles on both sides in the radial direction. Further, when the permanent magnet 32 is magnetized, it faces the magnetic sensor 31 in the axial direction of the output shaft 6. Aiming at the side end face, that is, if both sides of the end face close to the magnetic sensor 31 are intensively magnetized with two poles, the magnetic flux can be efficiently supplied from a place closer to the sensor detector 31a. it can.

  As described above, according to the non-contact rotation angle detection device according to the first embodiment, the permanent magnet is provided so that the N pole and the S pole are located in the radial direction at the shaft end portion of the rotation shaft that is the measurement target. A magnet and a magnetic flux direction detection type magnetic sensor that is disposed opposite to and spaced from the permanent magnet in the axial direction of the rotating shaft, and the permanent magnet is formed in a cylindrical shape having a hollow portion, and the axis of the rotating shaft Since it is fixed to the end portion, the magnetic flux stable region in the direction orthogonal to the axis of the rotation axis is widened, and it is possible to suppress the magnetic flux from increasing more than necessary. Furthermore, it is possible to make the change gradient of the magnetic flux gradual with respect to the change in the distance in the axial direction. For this reason, even if an axial misalignment between the axis of the rotating shaft and the center of the magnetic sensor occurs due to variations in component dimensions, bearing backlash, etc., the influence on the sensor output value due to the axial misalignment can be reduced. The permissible range of change in the distance between the axial magnetic sensor and the permanent magnet is widened, and dimensional management is facilitated.

  In addition, since the permanent magnet is magnetized with two poles on the side end surface facing the magnetic sensor in the axial direction of the rotating shaft, the magnetic flux can be supplied from a location closer to the sensor detection unit, to an unnecessary part. The magnetic flux leakage can be reduced as much as possible.

  In addition, when the magnetic sensor is composed of a GMR sensor, a highly sensitive sensor can be easily applied, so that a highly sensitive non-contact type rotation angle detecting device can be easily provided.

  Further, the shaft end portion of the rotating shaft is formed with a convex portion that can be fitted into the hollow portion of the permanent magnet, and the hollow portion is fitted into the convex portion and positioned, so that the axis of the permanent magnet with respect to the rotating shaft It can be easily fixed while suppressing the deviation. Moreover, since the positioning and fixing are performed in the hollow portion of the permanent magnet, a member for restraining the outer shape side of the permanent magnet is not necessary, and the outer diameter of the rotating shaft can be reduced.

  In addition, since the cross-sectional shape of the hollow portion orthogonal to the central axis of the permanent magnet is formed in a circular shape, it is not necessary to position the permanent magnet in the rotational direction when the permanent magnet is attached to the rotating shaft. It becomes easy.

Embodiment 2. FIG.
FIG. 5 is a plan view of the magnet unit of the non-contact rotation angle detection device according to the second embodiment, and corresponds to FIG. 3 of the first embodiment. Except for the part shown in FIG. 5, it is the same as FIG. 1 and FIG. 2 of the first embodiment. Also, parts equivalent to those in FIG. 3 are denoted by the same reference numerals, and detailed description thereof is omitted.

In FIG. 5, the permanent magnet 35 of the present embodiment is also provided with a hollow portion 35 a at the center thereof, but the cross-sectional shape of the hollow portion 35 a orthogonal to the central axis of the permanent magnet 35 is formed in a square or a rectangle. Has been. Two surfaces of the hollow portion 35a are parallel to the magnetic flux. Moreover, the cross-sectional shape of the convex part 6a of the output shaft 6 fitted to the hollow part 35a is also square or rectangular.
Since the end face on the sensor side of the permanent magnet 35 is magnetized in two poles, a section where the distance between the N pole and the S pole in the vicinity of the center of the output shaft 6 is equal is widened, and the width 33a of the magnetic flux stabilization region is secured wider. since it becomes possible to, it is possible to set a wider tolerance range of the axial misalignment R ₁ between the axis and the sensor detecting portion 31a center of the output shaft 6.

  As described above, according to the non-contact rotational angle detection device according to the second embodiment, the cross-sectional shape of the hollow portion orthogonal to the central axis of the permanent magnet is formed in a square or a rectangle. It is possible to secure a wider magnetic flux stable region. Therefore, compared with the first embodiment, it becomes easier to manage the dimension with respect to the axial deviation.

In addition, although the non-contact-type rotation angle detection device of the present invention has been described as applied to a range switching device that switches a shift range for a vehicle, the invention is not limited to this, and various actuators for vehicles or industrial use It can also be used as a rotation angle detection device for robots and machine tools.
In addition, within the scope of the present invention, the present invention can be freely combined with each other, or can be appropriately changed or omitted.

  DESCRIPTION OF SYMBOLS 1 Range switching device, 2 Substrate, 3 Motor, 4 Deceleration mechanism part, 5 Range switching part, 6 Output shaft, 6a Convex part, 7 Front body, 7a Support cylinder part, 8 Rear body, 9 Rotor, 10 Stator, 11 Motor shaft , 12 Front bearing, 13 Rear bearing, 14, 15 Bearing fixed part, 16 Planetary gear, 17 Internal gear, 18 Small gear, 19 Large gear, 20 Bearing member, 21 Shift shaft, 30 Rotation angle detector, 31 Magnetic Sensor, 31a Sensor detection part, 32, 35 Permanent magnet, 32a, 35a Hollow part, 33 Magnetic flux, 33a Width of magnetic flux stable region, 51 Shaft, 52 Permanent magnet, 53 Cover, 54 Magnetic sensor, 54a Sensor detection part, 55 Magnetic flux 55a Width of magnetic flux stabilization region

A non-contact rotation angle detection device according to the present invention includes a permanent magnet provided at a shaft end of a rotation shaft to be measured so that the N pole and the S pole are positioned in the radial direction of the rotation shaft, and the permanent magnet On the other hand, the permanent magnet is formed in a cylindrical shape having a hollow portion and is arranged opposite to and spaced apart in the axial direction of the rotation axis, and the axis is the axis of the rotation axis. The magnetic sensor is arranged with its center aligned with the axis of the permanent magnet .

According to a non-contact rotation angle detecting apparatus of the present invention, in opposition to the magnetic sensor, a permanent magnet provided on the shaft end of the rotating shaft to be measured is formed in a cylindrical shape having a hollow portion, that The shaft is aligned with the axis of the rotating shaft and fixed to the shaft end, and the magnetic sensor is arranged with its center aligned with the axis of the permanent magnet . Therefore, the magnetic flux is perpendicular to the axis of the rotating shaft. A stable region can be expanded, and an increase in magnetic flux more than necessary can be suppressed. Furthermore, it is possible to make the change gradient of the magnetic flux gradual with respect to the axial distance change. For this reason, even if an axial misalignment between the axis of the rotating shaft and the center of the magnetic sensor occurs due to variations in component dimensions, bearing backlash, etc., the influence on the sensor output value due to the axial misalignment can be reduced. The allowable range of the change in the distance between the axial magnetic sensor and the permanent magnet is widened, and dimensional management becomes easy.

As described above, according to the non-contact rotation angle detection device according to the first embodiment, the permanent magnet is provided so that the N pole and the S pole are located in the radial direction at the shaft end portion of the rotation shaft that is the measurement target. A permanent magnet is formed in a cylindrical shape having a hollow portion, and has an axial center on the axis. The magnetic sensor is fixed to the shaft end to match the axis of the rotating shaft, and the center of the magnetic sensor is aligned with the axis of the permanent magnet. It is possible to suppress the spread and increase of the magnetic flux more than necessary. Furthermore, it is possible to make the change gradient of the magnetic flux gradual with respect to the change in the distance in the axial direction. For this reason, even if an axial misalignment between the axis of the rotating shaft and the center of the magnetic sensor occurs due to variations in component dimensions, bearing backlash, etc., the influence on the sensor output value due to the axial misalignment can be reduced. The permissible range of change in the distance between the axial magnetic sensor and the permanent magnet is widened, and dimensional management is facilitated.

A non-contact rotation angle detection device according to the present invention includes a permanent magnet provided at a shaft end of a rotation shaft to be measured so that the N pole and the S pole are positioned in the radial direction of the rotation shaft, and the permanent magnet On the other hand, the permanent magnet is formed in a cylindrical shape having a hollow portion and is arranged opposite to and spaced apart in the axial direction of the rotation axis, and the axis is the axis of the rotation axis. The side end surface facing the magnetic sensor is magnetized in two poles in the axial direction of the rotating shaft, and the magnetic sensor is composed of a GMR sensor, the center of which is a permanent magnet. It is arranged according to the axis.

According to the non-contact rotation angle detection device of the present invention, the permanent magnet provided at the shaft end portion of the rotation shaft that is a measurement object facing the magnetic sensor is formed in a cylindrical shape having a hollow portion. The shaft center is aligned with the axis of the rotating shaft and fixed to the shaft end. In the axial direction of the rotating shaft, the side end surface facing the magnetic sensor is two-pole magnetized , and the magnetic sensor is composed of a GMR sensor. Since the center of the permanent magnet is arranged in accordance with the axis of the permanent magnet, a magnetic flux stable region in the orthogonal direction extends on the axis of the rotating shaft, and an increase in magnetic flux more than necessary can be suppressed. Furthermore, it is possible to make the change gradient of the magnetic flux gradual with respect to the axial distance change. For this reason, even if an axial misalignment between the axis of the rotating shaft and the center of the magnetic sensor occurs due to variations in component dimensions, bearing backlash, etc., the influence on the sensor output value due to the axial misalignment can be reduced. The allowable range of the change in the distance between the axial magnetic sensor and the permanent magnet is widened, and dimensional management becomes easy.
In addition, since the side end face facing the magnetic sensor is magnetized in two poles, magnetic flux can be supplied from a location closer to the sensor detection unit, and magnetic flux leakage to unnecessary portions can be reduced as much as possible.

Claims (6)

A permanent magnet provided at the shaft end of the rotating shaft to be measured so that the north and south poles are positioned in the radial direction of the rotating shaft;
A magnetic flux direction detection type magnetic sensor disposed opposite to the permanent magnet and spaced apart in the axial direction of the rotating shaft;
The non-contact rotation angle detection device, wherein the permanent magnet is formed in a cylindrical shape having a hollow portion and is fixed to the shaft end portion of the rotation shaft. In the non-contact-type rotation angle detection device according to claim 1,
The non-contact rotation angle detection device according to claim 1, wherein the permanent magnet is magnetized in two poles on a side end surface facing the magnetic sensor in the axial direction of the rotation shaft. In the non-contact-type rotation angle detection device according to claim 1 or 2,
The non-contact-type rotation angle detecting device, wherein the magnetic sensor is a GMR sensor. In the non-contact-type rotation angle detection device according to any one of claims 1 to 3,
The shaft end portion of the rotating shaft is formed with a convex portion that can be fitted into the hollow portion of the permanent magnet, and the hollow portion is fitted into the convex portion and positioned. Non-contact rotation angle detector. In the non-contact-type rotation angle detection device according to claim 4,
The non-contact rotation angle detection device according to claim 1, wherein the hollow portion perpendicular to the central axis of the permanent magnet has a circular cross-sectional shape. In the non-contact-type rotation angle detection device according to claim 4,
The non-contact rotation angle detection device according to claim 1, wherein a cross-sectional shape of the hollow portion orthogonal to the central axis of the permanent magnet is formed in a square or a rectangle.

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