JP2019211331A - Rotation angle detector - Google Patents

Abstract

To solve the problem that with a conventional rotation angle detector it is impossible to suppress the degradation of accuracy of detecting a change of eccentricity.SOLUTION: A rotation angle detector pertaining to the present application comprises: a rotor (1) having, as a rotation angle detection unit, an irregular part (12) composed of a magnetic substance on the outer circumferential surface; and a stator (2) provided facing the irregular part (12) and having a magnetic field generation part (22), a magnetic substance (24) and a magnetism detection part (23). The stator (2) and the rotor (1) are eccentric, and the irregular part (12) is an irregularity for N cycles (N=integer 1 or greater) with respect to a 360 degree machine angle in the circumferential direction of rotation of the rotor (1) and formed into an outer circumferential shape where angle errors at the time of maximum eccentricity in a prescribed direction and at the time of maximum eccentricity in a direction opposite the prescribed direction are equal.SELECTED DRAWING: Figure 2

Description

  The present application relates to a rotation angle detection device using a change in magnetic intensity.

  The rotation angle detection device is attached to a rotation shaft such as a motor and is used for detection of the rotation angle of the rotation shaft. The rotation angle detection device includes a rotor formed of a magnetic material on an outer peripheral surface; A stator provided opposite to the rotor, and the rotor is eccentric with respect to the center of the rotating shaft, and the gap between the rotor and the stator changes as the rotating shaft rotates. And the movement amount of the rotor is detected as a change in reluctance between the rotor and the stator by a plurality of detection coils.

  In this rotation angle detection device, the output waveform from the detection coil is an ideal waveform (sine wave or cosine wave) including a harmonic distortion (permeance error). The outer peripheral shape is detected by the effect of the shape of the uneven portion provided on this rotor as a structure with multiple uneven portions smaller than the predetermined eccentricity with respect to the perfect circle so as to cancel the permeance error of the detected waveform. In the output waveform of the coil, the amplitude of the fundamental wave component is increased, and it is closer to a sine wave to reduce the permeance error.

JP-A-8-163847

In the conventional technology, there is a problem that deterioration in detection accuracy cannot be suppressed with respect to an increase in the eccentricity. When an eccentricity generated due to an attachment error other than a predetermined eccentricity amount or vibration occurs, the worst value of the angle error at the time of either the positive or negative maximum eccentricity increases, and the detection accuracy deteriorates.
This application discloses the technique for solving the above subjects, and it aims at providing the rotation angle detection apparatus which suppressed the deterioration of detection accuracy.

  The rotation angle detection device according to the present application is provided with a rotor having a concavo-convex portion made of a magnetic material on an outer peripheral surface, and a fixed member provided opposite to the concavo-convex portion and having a magnetic field generation unit, a magnetic body, and a magnetic detection unit. The stator and the rotor are eccentric, and the concavo-convex portion corresponds to N cycles (N is an integer of 1 or more) with respect to a mechanical angle of 360 degrees in the circumferential direction of rotation of the rotor. There is provided a rotation angle detection unit having an outer peripheral shape that is uneven and has the same angular error at the time of maximum eccentricity in a predetermined direction and at the time of maximum eccentricity in the opposite direction to the predetermined direction.

  By equalizing the angle error at the time of maximum eccentricity in one direction and the maximum eccentricity on the opposite side, the worst value of the angle error when the maximum eccentricity is in either direction can be reduced, and deterioration of detection accuracy is suppressed. It becomes possible to do.

1 is a configuration diagram illustrating a configuration of a rotation angle detection device according to a first embodiment. FIG. 3 is a cross-sectional view illustrating a configuration of a stator and a rotor of a rotation angle detection unit according to the first embodiment. FIG. 3 is a cross-sectional view showing a configuration of a stator and a rotor of the rotation angle detection device according to the first embodiment. FIG. 3 is a cross-sectional view showing a configuration of a stator and a rotor of the rotation angle detection device according to the first embodiment. It is a schematic diagram which shows the relationship between the amount of eccentricity of FIG. 1, and an angle error. FIG. 6 is a cross-sectional view showing a configuration of a stator and a rotor of a rotation angle detection device according to a second embodiment. FIG. 6 is a schematic diagram showing cancellation of harmonic components accompanying one rotation of the rotor in FIG. 5. It is a block diagram which shows an example of the calculation of the magnetic flux density of the magnetic detection part of FIG. It is a block diagram which shows an example of the calculation of the magnetic flux density of the magnetic detection part of FIG. FIG. 6 is a cross-sectional view showing a configuration of a stator and a rotor of a rotation angle detection device according to a second embodiment. FIG. 6 is a cross-sectional view showing a configuration of a stator and a rotor of a rotation angle detection device according to Embodiment 3. FIG. 10 is an enlarged view of part A of the rotation angle detection device according to the third embodiment. FIG. 9 is a schematic diagram showing a gap length at a circumferential position in the third embodiment.

Embodiment 1 FIG.
FIG. 1 shows a configuration of a main part of the first embodiment of the rotation angle detection device. The rotation angle detection device includes a rotation angle detection unit 100, a processor 200, a storage device 300, a controller 400, and a data bus 500. The rotation angle detection unit 100 is connected to the processor 200, and the processor 200 is connected to the controller 400 through the data bus 500 and performs various controls based on values detected by the rotation angle detection unit 100.

  Although details of the storage device 300 are not shown, the storage device 300 includes a volatile storage device such as a random access memory and a nonvolatile auxiliary storage device such as a flash memory. Further, an auxiliary storage device of a hard disk may be provided instead of the flash memory. The processor 200 executes a program input from the storage device 300. In this case, a program is input from the auxiliary storage device to the processor 200 via the volatile storage device. Further, the processor 200 may output data such as an operation result to the volatile storage device of the storage device 300, or may store the data in the auxiliary storage device via the volatile storage device. Further, the processor 200 operates the controller 400 based on the result obtained by executing the program.

  FIG. 2 is a cross-sectional view illustrating the configuration of the rotor 1 and the stator 2 of the rotation angle detection unit 100 according to Embodiment 1 of the present application, and the rotor 1 in a state cut in a direction perpendicular to the rotation axis. And the relationship between the stator 2 and FIG. The rotation angle detection unit 100 according to Embodiment 1 includes a rotor 1 and a stator 2, and the stator 2 has a gap in the radial direction of the outer periphery of the rotor 1 (the direction of arrow A in the figure). It is opposed and extends in the outer circumferential direction (the direction of arrow B in the figure).

  The rotor 1 includes a rotation center axis 11 and a magnetic uneven portion 12 provided outside the rotation center axis 11 in the radial direction. The concavo-convex portion 12 is formed to change by N cycles with respect to a mechanical angle of 360 degrees in the circumferential direction when N is an integer of 1 or more. In other words, the shape of the outer periphery is an uneven shape with a period of N times. In the rotation angle detection unit 100 illustrated in FIG. 1, an uneven portion in the case of N = 12 is illustrated.

  The stator 2 is provided so as to face the uneven portion 12 of the rotor 1 with a gap. The stator 2 includes a magnetic field generation unit 22, one or a plurality of magnetic detection units 23 provided inside the magnetic field generation unit 22 in the radial direction, and a magnetic body 24 extending in the circumferential direction. . The magnetic field generator 22 is a coil or a magnet, and generates a magnetic field as a bias. The magnetic detection unit 23 is a coil, a Hall element, or a magnetoresistive element (MR element). The magnetic field generator 22 extends in the circumferential direction so as to cover the outside of the magnetic detector 23. The magnetic detection unit 23 is provided so as to face the concave and convex portion 12 of the rotor 1.

  The magnetic body 24 includes a magnetic body radial outer portion 241 provided on the radial outer side of the magnetic field generator 22 and a pair of magnetic body circumferential outer portions 242 sandwiching the magnetic field generator 22. The magnetic body radial direction outer side portion 241 extends in the circumferential direction so as to overlap the magnetic field generating portion 22. The outer circumferential portion 242 of the magnetic body protrudes radially inward from the magnetic field generator 22 and is connected to the outer radial portion 241 in the circumferential direction.

  The central axis 21 of the inner peripheral surface 243 of the magnetic body circumferential outer portion 242 facing the uneven portion 12 of the rotor 1 of the stator 2 is different from the central axis 11 of the rotor 1. In FIG. 2, the center axis 21 of the stator 2 is positioned in the direction of the arrow C <b> 1 on the plane with respect to the center axis 11 of the rotor 1 (that is, the lower direction in the drawing). Since the center axis 21 of the stator 2 is positioned on the lower side of the plane with respect to the center axis 11 of the rotor 1, the surface of the stator 2 that faces the uneven portion 12 of the rotor 1 and the uneven portion 12 The gap length is shorter than the gap length when the center axis 21 of the stator 2 and the center axis 11 of the rotor 1 are the same. The uneven portion 12 of the rotor 1 has a shape in which the gap permeance between the surface of the stator 2 facing the uneven portion 12 and the uneven portion 12 changes in a sine wave shape according to the rotation angle of the rotor 1.

  FIG. 3 shows a case where the center axis 21 of the stator 2 is located on the upper side (in the direction of the arrow C3 in the drawing) with respect to the center axis 11 of the rotor 1. As shown in FIG. 2, since the center axis 21 of the stator 2 is positioned on the upper side of the plane with respect to the center axis 11 of the rotor, the surface of the stator 2 that faces the uneven portion 12 of the rotor 1. The gap length of the concavo-convex portion 12 is longer than the gap length when the central axis 21 of the stator 2 and the central axis 11 of the rotor 1 are the same. The uneven portion 12 of the rotor 1 has a shape in which the gap permeance between the surface of the stator 2 facing the uneven portion 12 and the uneven portion 12 of the rotor 1 changes in a sine wave shape according to the rotation angle of the rotor 1. doing.

FIG. 4 shows a case where the central axis 21 of the stator 2 is in a position eccentric in the lateral direction on the plane (direction of the arrow C3) with respect to the central axis 11 of the rotor 1. In FIG. 4, the gap length between the inner peripheral surface 243 of the magnetic body circumferential outer portion 242 and the uneven portion 12 of the rotor 1 is different on the left and right. The uneven portion 12 of the rotor 1 has a shape in which the gap permeance between the surface of the stator 2 facing the uneven portion 12 and the uneven portion 12 changes in a sine wave shape according to the rotation angle of the rotor 1.
That is, as shown in FIGS. 2, 3, and 4, when the stator 2 is a partial arc, the position of the center axis 21 of the stator 2 and the position of the center axis 11 of the rotor 1 approach and move away from each other. There are three patterns in the horizontal direction.

  In order to improve the detection accuracy of the rotation angle, it is necessary to reduce the harmonic component of the magnetic flux density detected by the magnetic detection unit 23 according to the rotation angle of the rotor 1. The magnetic flux density is determined by the product of the magnetomotive force of the magnetic field generator 22 and the gap permeance between the surface of the stator 2 facing the uneven portion 12 of the rotor 1 and the uneven portion 12 of the rotor 1. Since the magnetomotive force of the magnetic field generator 22 is constant, the amount of change in magnetic flux density is defined by the amount of change in gap permeance. Reducing the harmonic component of the magnetic flux density is synonymous with reducing the harmonic component of the gap permeance. In the conventional rotation angle detection unit 100, since the center axis 21 of the stator 2 and the center axis 11 of the rotor 1 are made to coincide with each other, there arises a problem that an angle error increases when an eccentricity occurs.

  In the rotation angle detection unit 100 of the first embodiment, the central axis 21 of the inner peripheral surface on the outer side in the circumferential direction of the magnetic body of the stator 2 facing the concave and convex portion 12 of the rotor 1 is different from the central axis 11 of the rotor 1. . At this time, the uneven portion 12 of the rotor 1 has a shape in which the gap permeance between the surface of the stator 2 facing the uneven portion 12 and the uneven portion 12 of the rotor 1 is sinusoidal. The uneven portion 12 of the rotor 1 is formed in advance so that the gap permeance between the stator 2 and the rotor 1 becomes a sine wave at a position where the center axis 21 of the stator 2 and the center axis 11 of the rotor 1 are different from each other. By doing so, the detection accuracy of the rotation angle detection unit 100 at the time of eccentricity can be improved.

  In FIG. 2, the center axis 21 of the stator is located below the center axis 11 of the rotor. FIG. 5 shows the relationship between the amount of eccentricity and the angle error. In FIG. 5, the broken line (1) shows the case of the present application, and the solid line (2) shows the case of the prior art. As shown in this figure, assuming that the stator 2 and the rotor 1 are moved away (when the gap length is increased) and approached (when the gap length is decreased), it is compared with the case where the gap length is moved away. Thus, when the gap length between the stator 2 and the rotor 1 is closer, the sensitivity of the gap permeance with respect to the eccentricity is higher.

  Therefore, when the gap length between the stator 2 and the rotor 1 approaches, the ratio of the harmonic component to the eccentric amount becomes higher, and the angular error with respect to the eccentric amount becomes larger. In the conventional rotation angle detection device, the concave and convex portions of the rotor 1 so that the gap permeance between the stator 2 and the rotor 1 is sinusoidal at the same position of the center axis 21 of the stator and the center axis 11 of the rotor 1. 12 is shown, but there is a problem that the angular error becomes large at the position of the maximum eccentricity when the stator 2 and the rotor 1 are eccentric in the approaching direction.

  In the rotation angle detection unit 100 of FIG. 2, the uneven portion 12 of the rotor 1 is formed so that the gap permeance between the stator 2 and the rotor 1 becomes a sine wave at a position where the gap length between the stator 2 and the rotor 1 approaches. Forming. The shape of the concavo-convex portion 12 of the rotor 1 has a shape that changes so that the angle error between the maximum eccentricity in a certain direction and the maximum eccentricity on the opposite side becomes equal. As a result, as shown in FIG. 5, the angular error can be suppressed at the position of the maximum eccentricity when the stator 2 and the rotor 1 are eccentric in the approaching direction. As a result, it is possible to suppress deterioration in detection accuracy at the position of the maximum eccentricity.

  In the rotation angle detection unit 100 according to the first embodiment, the stator 2 is opposed to the rotor 2 at an angle within a predetermined range of 360 degrees. In other words, the stator 2 faces only a part of the rotor 1 in the circumferential direction. Further, the outer end 244 and the outer end 245 on the outer circumferential side of the magnetic body sandwiching the magnetic field generating unit 22 configured as a part of the stator 2 in the circumferential direction are provided up to a predetermined range. It does not wrap around the whole child 1. Therefore, the weight of the magnetic body circumferential direction outer side portion 242 can be minimized.

Embodiment 2. FIG.
FIG. 6 is a cross-sectional view showing the rotation angle detection unit 100 according to the second embodiment. In the rotation angle detection unit 100 according to the second embodiment, the same stator 2 as that of the first embodiment is arranged, and further, the second stator 3 is arranged on the facing surface located at a mechanical angle of 180 degrees in the circumferential direction. ing. The inner circumferential surface 243 of the magnetic body circumferential outer portion 242 of the stator 2 and the inner circumferential surface 343 of the second magnetic body circumferential outer portion of the second stator 3 are located on the same circumference.

  In FIG. 6, the central axis 21 of the stator 2 is positioned on the upper side (in the direction of the arrow C <b> 4) on the plane with respect to the central axis 11 of the rotor 1. The case where the center axis 21 of the stator 2 is shifted upward with respect to the center axis 11 of the rotor 1 has the same significance. The shape of the concavo-convex portion 12 of the rotor 1 has a shape in which the gap permeance between the surface of the stator 2 facing the concavo-convex portion 12 and the concavo-convex portion 12 changes in a sine wave shape according to the rotation angle of the rotor 1. Yes.

  Other configurations are the same as those of the first embodiment. As in the first embodiment, the rotor is arranged so that the gap permeance between the stator 2 and the rotor 1 becomes a sine wave at a position where the center axis 21 of the stator 2 and the center axis 11 of the rotor 1 are decentered in advance. By forming one uneven portion 12, it is possible to obtain an effect of improving the detection accuracy of the rotation angle detection unit 100 at the time of eccentricity.

  By forming another stator 2 on the opposing surface located at a mechanical angle of 180 degrees, it is possible to cancel the harmonic components that accompany the rotor 1 making one revolution. FIG. 7 shows harmonic components accompanying the rotation in the rotor 1 in the magnetic flux density waveforms of the magnetic detection unit 23 and the second magnetic detection unit 33 of the stator 2. In the rotation angle detection unit 100, a sine wave of an N-cycle fundamental wave is obtained as the rotor 1 rotates once. As a component that deteriorates the detection accuracy, a sine wave of one cycle appears with one rotation of the rotor 1 as shown in FIG. 7, but the magnetic flux density waveform A of the magnetic detection unit 23 and the second magnetic detection unit 33 Since the magnetic flux density waveform B has an opposite phase, it can be canceled by adding the magnetic flux density waveform A of the magnetic detection unit 23 and the magnetic flux density waveform B of the second magnetic detection unit 33 together. As a result, detection accuracy can be improved.

  FIG. 8 is a block diagram showing the calculation of the magnetic flux density of the magnetic detector 23 of the stator 2 and the magnetic flux density of the second magnetic detector 33. Calculation is performed to add a plurality of magnetic flux densities of the magnetic detection unit 23 and the second magnetic detection unit 33. FIG. 8 shows a calculation for adding the detection values of the magnetic detection units at the corresponding positions. As shown in FIG. 8, by adding the detected values, as described in FIG. 7, it is possible to cancel the harmonic component that accompanies when the rotor 1 makes one rotation. In addition, although each is a block diagram of three magnetic flux densities, it is the same also with two or three or more magnetic flux densities. Further, after a plurality of magnetic flux densities are processed, they may be added together. For example, as shown in FIG. 9, the plurality of magnetic flux densities of the first and second magnetic detectors may be converted into the magnetic flux densities of SIN and COS, respectively, and the SINs and COSs may be added together.

  This arithmetic processing is performed in the processor 200 shown in FIG. For example, the processor 200 performs an arithmetic process on the output data of the magnetic detection unit 23 and the second magnetic detection unit 33 in the rotation angle detection unit 100 based on a program stored in the storage device 300.

  FIG. 10 shows a case where the center axis 21 of the stator 2 is positioned in the horizontal direction on the plane (the direction of the arrow C3) with respect to the center axis 11 of the rotor 1. The uneven portion 12 of the rotor 1 has a shape in which the gap permeance changes in a sine wave shape depending on the rotation angle of the rotor 1 between the surface of the stator 2 facing the uneven portion 12. Also in the shape of FIG. 10, the same effect as the shape of FIG. 6 can be obtained.

Embodiment 3 FIG.
FIG. 11 is a cross-sectional view showing the rotation angle detection unit 100 according to the third embodiment. FIG. 12 is an enlarged view showing a part A of the rotation angle detection unit 100 of FIG. In FIG. 11, as in the first embodiment, the center axis 21 of the stator 2 is at a position decentered in the direction of the arrow C <b> 4 with respect to the center axis 11 of the rotor 1.

  In FIG. 12, the gap length between the stator 2 and the uneven portion 12 of the rotor 1 is Lg, the maximum value of the gap length between the stator 2 and the uneven portion 12 is Lgmax, and the minimum value is Lgmin. The radial thickness is Lm, the relative permeability of the magnetic field generator 22 is μr, the amplitude of the zero-order component of the magnetic flux density linked to the magnetism detector 23 is Bo, the amplitude of the primary component is B1, The difference between the inner diameters of the stator 2 and the magnetic field generator 22 is L1, and the constant is A. When the center axis 21 of the stator 2 and the center axis 11 of the rotor 1 are different, the gap length between the stator 2 and the rotor 1 in the concavo-convex portion 12 of the rotor 1 is expressed by the following equation (1).

  In the formula (1), when the term Asin2Nθ is excluded, the gap length Lg between the stator 2 facing the concavo-convex portion 12 of the rotor 1 and the concavo-convex portion 12 of the rotor 1 is rotated with the central axis 21 of the stator 2. The shape of the uneven part 12 when the center axis 11 of the child 1 is the same is represented. Therefore, the term Asin2Nθ is a correction term when the position of the central axis 21 of the stator 2 and the position of the central axis 11 of the rotor 1 are different. When the position of the central axis 21 of the stator 2 and the position of the central axis 11 of the rotor 1 are different, in addition to the fundamental wave component of the gap permeance, a 2N order component of the gap permeance for one period of the mechanical angle is generated. Therefore, the gap permeance can be made sinusoidal by adding the correction term Asin2Nθ to the gap length Lg between the stator 2 and the concavo-convex portion 12 facing the concavo-convex portion 12 of the rotor 1.

式（４）において、定数をＣ、ｉ、ｊは、次の式（５）、（６）、（７）としている。 Equations (2) and (3) represent equations for calculating the zeroth-order component amplitude B0 and the first-order component amplitude B1 of the magnetic flux density linked to the magnetic detection unit 23 in the formula (1).
In Equation (1), if the constants are C, i, and j, the gap length between the rotor 1 and the stator 2 in the concavo-convex portion 12 can be converted to the following Equation (4).

In Expression (4), constants C, i, and j are the following Expressions (5), (6), and (7).

  When the center axis 21 of the stator is different from the center axis 11 of the rotor, the shape of the concavo-convex portion 12 of the rotor 1 is expressed by the formula (4), that is, the shape of the concavo-convex portion 12 is the same between the stator and the rotor. Since the gap length has the dimension of the formula (4), it is possible to provide the rotation angle detection unit 100 in which the detection accuracy is improved even when eccentric.

  In Expression (4), the first term and the third term are components whose gap permeance is a sine wave. The second term Asin2Nθ is a harmonic component. By superimposing harmonic components in the state before eccentricity occurs, it is possible to equalize the angle error at the time of maximum eccentricity for both positive and negative, and to reduce the worst value of the angle error at the time of maximum eccentricity. .

  FIG. 13 is a schematic diagram illustrating a state in which the gap length between the inner surface of the stator 2 facing the concavo-convex portion 12 of the rotor 1 and the concavo-convex portion 12 is a point sequence with respect to the circumferential position. In production, the gap length is sampled at a constant circumferential interval. In FIG. 13, a straight line is interpolated between the point sequences. Linear interpolation between point sequences can be easily performed, and deterioration in detection accuracy can be suppressed. In addition, the gap length point sequence interpolation can also be performed by spline interpolation or Lagrange interpolation.

Although this disclosure describes various exemplary embodiments and examples, various features, aspects, and functions described in one or more embodiments are not limited to a particular embodiment. The present invention is not limited to the application, and can be applied to the embodiments alone or in various combinations.
Accordingly, countless variations that are not illustrated are envisaged within the scope of the technology disclosed herein. For example, the case where at least one component is deformed, the case where the component is added or omitted, and the case where the at least one component is extracted and combined with the component according to another embodiment are included.

1 rotor, 2 stator, 3 second stator, 11 central axis of the rotor,
12 Concavity and convexity part, 21 Stator central axis, 22 Magnetic field generation part, 23 Magnetic detection part, 24 Magnetic body, 241 Magnetic body radial outer part, 242 Magnetic body circumferential outer part,
243 inner peripheral surface, 244, 245 outer end portion, 33 second magnetic detection portion,
343 inner circumferential surface of the second magnetic body circumferential outer side, 100 rotation angle detection unit,
200 processors, 300 storage devices, 400 controllers, 500 data buses

Claims (6)

  A rotor having a concavo-convex portion made of a magnetic material on an outer peripheral surface; and a stator provided opposite to the concavo-convex portion and having a magnetic field generation unit, a magnetic body, and a magnetic detection unit, the stator and the The rotor is eccentric, and the concavo-convex portion is concavo-convex for N periods (N is an integer of 1 or more) with respect to a mechanical angle of 360 degrees in the circumferential direction of rotation of the rotor, and is the maximum in a predetermined direction. A rotation angle detection device comprising a rotation angle detection unit having an outer peripheral shape in which an angle error between an eccentricity and a maximum eccentricity in a direction opposite to the predetermined direction is equal.   The rotation angle detection device according to claim 1, wherein the stator faces a part of the rotor in the circumferential direction.   When the stator and the rotor are decentered in the direction in which the gap length between the stator and the concavo-convex part is shortened, the outer peripheral shape of the concavo-convex part is the gap permeance between the stator and the rotor. 3. The rotation angle detection device according to claim 2, wherein the rotation angle detection device changes in a sinusoidal shape according to the rotation angle.   The gap length between the stator and the concavo-convex portion is 2N with respect to a mechanical angle of 360 degrees in addition to a component in which the gap permeance between the concavo-convex portion of the rotor and the stator becomes a sine wave in a state before eccentricity occurs. The rotation angle detection device according to claim 1, further comprising a component that becomes a next sine wave. When the gap length between the concavo-convex portion of the rotor and the stator is Lg and the constants are A, C, i, j, the concavo-convex portion has a gap length between the stator and the rotor of the following formula: The rotation angle detecting device according to claim 1, wherein

  A second stator having a second magnetic detector is provided at a mechanical angle of 180 degrees in the circumferential direction of the rotor with respect to the position where the stator is provided. 2. The rotation angle detection device according to claim 1, wherein a calculation process for adding the value and the detection value of the second magnetic detection unit is performed.

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