JP6779333B2 - Rotation angle detector - Google Patents

Description

The present application relates to a rotation angle detection device.

As a rotation angle detecting device, a technique for detecting a rotation angle by detecting a change in magnetic flux due to a change in the gap permeance between the rotor and the stator is generally known. For example, magnetism that detects the rotation angle from the change in magnetic resistance by arranging a stator with a plurality of magnetoresistive elements arranged along the circumferential direction facing the outer peripheral surface of the rotor whose diameter changes along the circumferential direction. The sensor is disclosed (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2006-329888 (paragraphs 0002 to 0003, FIGS. 3 to 5, paragraphs 0014 to 0020, and FIGS. 1 to 2).

However, in the above-mentioned magnetic sensor, it is necessary to arrange the element for magnetic detection in a range of an electric angle of 180 degrees or more, which makes it difficult to miniaturize and obtain a highly accurate signal component.

The present application discloses a technique for solving the above-mentioned problems, and an object of the present application is to obtain a compact and accurate rotation angle detecting device.

The rotation angle detecting device disclosed in the present application is a rotor having a concavo-convex portion of a magnetic material that is rotatably supported around a rotation axis and whose outer peripheral surface diameter changes N times periodically, and the outer circumference of the rotor. A magnetic field generating part that faces the surface at intervals and generates a magnetic field between the uneven part and the peripheral direction, which is less than the value obtained by dividing 180 degrees by N in the mechanical angle and 180 degrees in the electric angle. Based on the detection signals from each element of the stator and the element group, which are arranged in the range less than or equal to, and are composed of three or more magnetic detection elements for detecting the generated magnetic field, and the stator having the same. A part of the elements in the element group was selected and selected according to the rotation angle calculation processing unit for calculating the rotation angle of the rotor and the number of elements which is the number of the magnetic detection elements in the element group. It is characterized by being provided with a positive / negative inversion mechanism that inverts the detection signal from the element.

According to the rotation angle detection device disclosed in the present application, a compact and accurate rotation angle detection device can be obtained by arranging the magnetic detection element within a range of less than half an electric angle period.

It is a schematic diagram which shows the whole structure of the rotation angle detection apparatus which concerns on Embodiment 1. FIG. It is a partially enlarged schematic diagram of the rotation angle detection device which concerns on Embodiment 1. FIG. It is a functional block diagram for demonstrating the structure of the rotation angle calculation processing part of the rotation angle detection apparatus which concerns on Embodiment 1. FIG. It is a figure which shows the magnetic flux density waveform output from three magnetic detection elements in the rotation angle detection apparatus which concerns on Embodiment 1. FIG. FIG. 5 is a diagram showing a magnetic flux density waveform obtained by positive / negative inversion processing of the waveform of one magnetic detection element after DC offset correction of the magnetic flux density waveforms from the three magnetic detection elements in the rotation angle detection device according to the first embodiment. FIG. 5 is a diagram showing a magnetic flux density waveform obtained by positive / negative inversion processing of the waveforms of the two magnetic detection elements after DC offset correction of the magnetic flux density waveforms from the three magnetic detection elements in the rotation angle detection device according to the first embodiment. FIG. 5 is a partially enlarged schematic view when five magnetic detection elements are provided as the rotation angle detection device according to the first modification of the first embodiment. It is a figure which shows the magnetic flux density waveform output from 5 magnetic detection elements in the rotation angle detection apparatus which concerns on 1st modification of Embodiment 1. FIG. In the rotation angle detection device according to the first modification of the first embodiment, the magnetic flux density waveforms from the five magnetic detection elements are corrected by DC offset, and then the waveforms of some of the magnetic detection elements are positively and negatively inverted. It is a figure which shows. It is a partially enlarged schematic diagram when seven magnetic detection elements are provided as the rotation angle detection device according to the second modification of the first embodiment. It is a figure which shows the magnetic flux density waveform which is output from seven magnetic detection elements in the rotation angle detection apparatus which concerns on the 2nd modification of Embodiment 1. FIG. In the rotation angle detection device according to the second modification of the first embodiment, the magnetic flux density waveforms from the seven magnetic detection elements are corrected by DC offset, and then the waveforms of some of the magnetic detection elements are positively / negatively inverted. It is a figure which shows. It is a block diagram which shows the structural example of the part which executes the calculation process of the rotation angle of the rotation angle detection apparatus which concerns on Embodiment 1. It is a partially enlarged schematic diagram of the rotation angle detection device which concerns on Embodiment 2. FIG. It is a figure which shows the magnetic flux density waveform output from three magnetic detection elements in the rotation angle detection apparatus which concerns on Embodiment 2. FIG. FIG. 5 is a diagram showing a magnetic flux density waveform obtained by DC offset correction of magnetic flux density waveforms from three magnetic detection elements in the rotation angle detection device according to the second embodiment. It is a partially enlarged schematic diagram of the rotation angle detection device which concerns on Embodiment 3. FIG. It is a partially enlarged schematic diagram of the rotation angle detection device which concerns on the modification of Embodiment 3. 19A and 19B are a cross-sectional view perpendicular to the axial direction of the stator of the rotation angle detection device according to the fourth embodiment and a side view of the stator on the side facing the rotor, respectively. It is a figure which shows the magnetic flux density waveform output from four magnetic detection elements in the rotation angle detection apparatus which concerns on Embodiment 4. FIG. It is a figure which shows the magnetic flux density waveform which DC offset corrected the magnetic flux density waveform from four magnetic detection elements in the rotation angle detection apparatus which concerns on Embodiment 4. FIG.

Embodiment 1.
1 to 6 are for explaining the configuration and operation of the rotation angle detection device according to the first embodiment, and FIG. 1 shows the axial direction of the rotor and the stator as the overall configuration of the rotation angle detection device. FIG. 2 is a schematic view showing a signal connection between a cross-sectional shape showing a positional relationship in a plane direction perpendicular to and a rotation angle calculation processing unit. FIG. 2 shows a rotor and a stator of the rotation angle detection device in FIG. 1 facing each other. It is an enlarged schematic view of the vicinity of a portion, and FIG. 3 is a functional block diagram for explaining the configuration of the rotation angle calculation processing unit.

4 is a diagram showing magnetic flux density waveforms output from each magnetic detection element to the rotation angle calculation processing unit when three magnetic detection elements are arranged on the stator, and FIG. 5 is a diagram showing the three magnetic flux density waveforms shown in FIG. It is a figure which shows the magnetic flux density waveform which performed the positive / negative inversion processing of the waveform of the magnetic detection element located in the center in the circumferential direction by the positive / negative inversion part after DC offset correction of the magnetic flux density waveform from a magnetic detection element by a DC offset correction part. On the other hand, FIG. 6 shows the magnetic flux densities obtained by correcting the magnetic flux density waveforms from the three magnetic detection elements shown in FIG. 4 by DC offset correction, and then performing positive / negative inversion processing on the waveforms of the magnetic detection elements located at both ends in the circumferential direction by the positive / negative inversion portions. It is a figure which shows the waveform.

Hereinafter, description will be made with reference to the drawings.
The rotation angle detection device is, for example, directly connected to a shaft or the like of a rotary electric machine, detects the rotation angle or the number of rotations of the rotary electric machine, and is used for rotation control, measurement, or the like. As shown in FIG. 1, the rotation angle detection device 1 according to the first embodiment is arranged so as to face the rotor 10 that rotates about the rotation axis Xr and the outer peripheral surface 10fo of the rotor 10 as a mechanical configuration. It is provided with a stator 20. Then, as a configuration for performing arithmetic processing, a rotation angle calculation processing unit 30 for processing signals output from each of the plurality of magnetic detection elements 22 of the stator 20 to calculate a rotation angle is provided.

The rotor 10 is directly connected to a shaft or the like of a rotating electric machine (not shown), and is provided so as to rotate about a rotating shaft Xr in conjunction with the rotating electric machine. The outer peripheral surface 10fo side is provided with a concavo-convex portion 12 of a magnetic material whose outer diameter changes periodically along the circumferential direction. The concavo-convex portion 12 is formed by N concavo-convex parts (concave portion 12t and convex portion 12p) so as to change N cycles with respect to a mechanical angle of 360 degrees along the circumferential direction when N is an integer of 1 or more. Will be done. Generally, N (referred to as the number of unevenness) is set to a multiple of the number of magnetic pole pairs of the rotary electric machine, but in this example, the uneven portion 12 set to N = 12 is shown. Further, in this example, the diameter changes so as to draw a sine wave.

The stator 20 is arranged so as to face the outer peripheral surface 10fo of the uneven portion 12 portion of the rotor 10, and has a magnetic field generating portion 21 that generates a magnetic field with the concave-convex portion 12, a plurality of magnetic detection elements 22, and magnetism. It has a back surface portion 23 of the body. Each of the magnetic detection elements 22 has the same distance from the rotation axis Xr, and is arranged at equal intervals along the circumferential direction so as to face the outer peripheral surface 10fo of the uneven portion 12 portion of the rotor 10. As a result, the distance between each of the plurality of magnetic detection elements 22 and the outer peripheral surface 10fo of the concave-convex rotor 10 changes periodically as the rotor 10 rotates. The magnetic field generation unit 21 is located outside in the radial direction with respect to the magnetic detection element 22, and extends at a constant distance from the rotation axis Xr so as to cover the arrangement range of the magnetic detection element 22 in the circumferential direction. ..

The back surface portion 23 is formed of a magnetic material so that a portion that covers the outer side in the radial direction with respect to the magnetic field generating portion 21 is connected to a portion that covers both end faces in the circumferential direction of the magnetic field generating portion 21. Although it can be detected only by the magnetic detection element 22 and the magnetic field generation unit 21, the amplitude of the magnetic flux density waveform obtained from each output signal of the magnetic detection element 22 can be increased by arranging the back surface portion 23 of the magnetic material. Can be done. This makes it possible to reduce the quantization error when converting an analog signal to a digital signal, and improves the detection accuracy.

Next, the arrangement of the magnetic detection element 22 will be described. The number of locations evenly arranged along the circumferential direction (number of arrangement locations L) is L = n when the number n of the magnetic detection elements 22 is an odd number of 3 or more. Then, the angle θg of the range in which each magnetic detection element 22 is arranged in the circumferential direction is set to less than 180 / N obtained by dividing the mechanical angle of 180 degrees by the number of irregularities N of the uneven portion 12. By arranging the magnetic detection element 22 in a range narrower than the range of the electric angle half cycle, the installation range of the magnetic field generating portion 21 and the back surface portion 23 of the stator 20 in the circumferential direction can be reduced, and the device can be miniaturized. It will be possible. In FIG. 1, since the number of irregularities N = 12, the angle θg of the arrangement range of the magnetic detection element 22 is less than the mechanical angle of 15 degrees.

For example, as in Patent Document 1, when the peak of the waveform from each element is simply detected and the angle is calculated, in the process of converting the polyphase signal into a two-phase signal, the magnetic detection element has a mechanical angle in the circumferential direction. It had to be placed in the range of 360 / N degrees. In the present application, as will be described later, among the plurality of magnetic detection elements 22, for example, when the number of elements n is odd, only the even-numbered signals or only the odd-numbered signals in the order along the circumferential direction are used. In addition, every other signal was configured to invert the positive and negative signals. The case where the number of elements n is an even number will be described in the fourth embodiment.

In this way, even when the magnetic detection element 22 is arranged in a range of less than 180 / N degrees by the inversion processing of a part of the signals extracted regularly from the magnetic detection element 22, the mechanical angle It is possible to acquire a signal similar to that in which the element is arranged in the range of 360 / N degrees. Therefore, even when the plurality of magnetic detection elements 22 are arranged in a range of less than 180 / N degrees of mechanical angle, the polyphase signal can be converted into a two-phase signal to detect the rotation angle position with high accuracy.

In particular, in the present embodiment, as shown in FIG. 2, the intervals (angle θs) between the magnetic detection elements 22 adjacent in the circumferential direction are arranged so that the mechanical angle is 180 / (N × L) degrees. .. As a result, a phase (= n) signals with a phase shift of 180 / L degrees of electrical angle can be obtained from each magnetic detection element 22.

Here, when the magnetic detection elements 22 are arranged at a mechanical angle of 180 / (N × L) degrees, the distance (angle θg) from the magnetic detection element 22 on one end side to the magnetic detection element 22 on the other end side in the circumferential direction. Is a mechanical angle of 180 × (L-1) / (N × L) degrees. Then, as the number of locations L of the magnetic detection elements 22 increases, the mechanical angle in the range in which the magnetic detection elements 22 are arranged gradually approaches 180 / N degrees. On the other hand, regarding the range of the electric angle, when the number of arrangement locations L is increased to 10, 20, 30 ..., it approaches 180 degrees to 162 degrees, 171 degrees, 174 degrees, ..., But less than 180 ( It falls within the range of less than half a lap).

For example, when the number of arrangement locations L = 3, as in this example, the distance θs between adjacent magnetic detection elements 22 is 60 / N degrees, and the angle θg from the magnetic detection element 22 _U to the magnetic detection element 22 _W is. It becomes 120 / N degrees. Therefore, the magnetic detection element 22 is arranged in a range where the mechanical angle is less than 180 / N degrees. This means that the magnetic detection elements 22 are arranged at equal intervals within a range of less than half an electrical angle period, and the occupied range of the magnetic field generating portion 21 and the back surface portion 23 of the stator 20 in the circumferential direction can be narrowed. , The device can be miniaturized.

The configuration and operation of the rotation angle calculation processing unit 30 that executes the calculation processing will be described on the premise of the above-mentioned mechanical configuration. As shown in FIG. 3, the rotation angle calculation processing unit 30 mainly extends from the DC offset calculation unit 31 that calculates the DC offset value of the signal received from each magnetic detection element 22 to the angle calculation unit 35 that calculates the rotation angle. It is composed of 5 blocks.

The DC offset calculation unit 31 calculates the shift amount from the reference value for the DC component of the detection signal received from each of the plurality of magnetic detection elements 22, and obtains the DC offset value. The DC offset value is calculated by averaging one cycle of the electric angle of each waveform. The offset value is not limited to the averaging process. For example, it is possible to calculate the shift amount from the reference value from the maximum value and the minimum value of the waveform for each waveform to obtain the DC offset value. , Can be changed as appropriate.

The DC offset correction unit 32 uses the offset value for each magnetic detection element 22 calculated by the DC offset calculation unit 31 to perform offset processing by subtracting the offset value from each detection signal of the n magnetic detection elements 22.

The positive / negative inversion unit 33 inverts the positive / negative of the signal of every other magnetic detection element 22 in the order of arrangement in the circumferential direction among the signals derived from each magnetic detection element 22 offset processed by the DC offset correction unit 32. That is, in the order of arrangement, the target to be reversed and the target not to be reversed are alternated. For example, among the three magnetic detection elements 22 _U , 22 _V , and 22 _W arranged in the circumferential direction in FIG. 2, the positive and negative of the signal derived from the central magnetic detection element 22 _V corresponding to the even number is inverted.

For example, as shown in FIG. 2, from each of the three magnetic detection elements 22 _U , 22 _V , and 22 _W arranged in the circumferential direction, the electrical angle (horizontal axis) is 60 degrees (as shown in FIG. 4). = 180 / L) Three-phase sinusoidal waveforms P _U , P _V , and P _W (collectively referred to as detection waveforms) that are out of phase with each other can be obtained. However, in the waveform group of this detected waveform, the position of the peak of the magnetic flux density (vertical axis) on the horizontal axis appears biased to a range of less than half of the electric angle of 360 degrees.

On the other hand, when each of the three-phase sinusoidal waveforms P _U , P _V , and P _W is offset processed and the positive and negative of the signal derived from the central magnetic detection element 22V corresponding to the even number is inverted, it is shown in FIG. As described above, three-phase sinusoidal waveforms Pp _U , Pp _W , and Pp _V (collectively referred to as processed waveforms) having a phase shift of 120 degrees by an electric angle can be obtained. That is, it is possible to obtain a waveform group of processed waveforms having the number of phases a corresponding to the number of elements n in which the phases are evenly shifted within the electric angle of 360 degrees and the peak positions or zero cross points appear at equal intervals.

After that, the a-phase-2 phase conversion unit 34 converts the three processed waveforms into three-phase / two-phase conversion, which is an a-phase-2 phase conversion, and does not assign SIN and COS codes whose phases differ by 90 degrees. Find the phase signal. By performing the a-phase to two-phase conversion, the tertiary component of the detection signal, which is an in-phase component, can be removed, and the detection accuracy can be improved. After that, the angle calculation unit 35 calculates the rotation angle by calculating the tangent inverse function of the converted two-phase signal.

In the positive / negative inversion process, the same result can be obtained not only when the processing target is set to the even number but also when the processing target is set to the odd number. For example, among the three magnetic detection elements 22 _U , 22 _V , and 22 _W arranged in the circumferential direction in FIG. 2, the positive and negative of the signals derived from the magnetic detection elements 22 _U , 22 _{W at} both ends corresponding to the odd numbers are inverted. May be good. Also in that case, as shown in FIG. 6, three-phase sinusoidal waveforms Pp _V , Pp _U , and Pp _W, which are out of phase by 120 degrees in terms of electrical angle, can be obtained. After that, by performing three-phase to two-phase conversion on the obtained three processed waveforms, the third-order component of the detection signal, which is an in-phase component, can be removed, and the detection accuracy can be improved. ..

Modification example 1.
In the above example, an example in which three magnetic detection elements are arranged has been described, but the present invention is not limited to this, and any number of magnetic detection elements may be three or more. In the present modification 1 (first modification), an example in which five magnetic detection elements are arranged will be described. 7 to 9 are for explaining the configuration and operation of the rotation angle detection device according to the first modification, and FIG. 7 shows the vicinity of the portion where the rotor and the stator of the rotation angle detection device face each other (FIG. 7 to 9). FIG. 8 is an enlarged schematic view (corresponding to FIG. 2), and FIG. 8 is a diagram showing a magnetic flux density waveform output from each magnetic detection element to the rotation angle calculation processing unit when five magnetic detection elements are arranged on the stator. (Corresponding to FIG. 4), FIG. 9 shows that the magnetic flux density waveforms from the five magnetic detection elements are corrected by the DC offset correction unit, and then the positive and negative inversion units are used to positively and negatively correct the waveforms of the two magnetic detection elements located at even positions. It is a figure (corresponding to FIG. 5) which shows the magnetic flux density waveform which performed the inversion process.

In the present modification 1, as shown in FIG. 7, five magnetic detection elements 22 _A , 22 _B , 22 _C , 22 _D , and 22 _E are evenly arranged in the circumferential direction (the number of arrangement locations), assuming that the number of elements is n = 5. L = 5). Even when the number of elements is n = 5, the magnetic detection elements 22 are arranged at equal intervals of a mechanical angle of 180 / (N × L) degrees with L = n. In that case, the signals output from each magnetic detection element 22 are at intervals of 36 degrees within a range of an electric angle of 144 degrees (<180 degrees). When N = 12, θs is 3 degrees and θg is 12 degrees.

In the case of such a configuration, from each of the five magnetic detection elements 22 _A , 22 _B , 22 _C , 22 _D , and 22 _E , the electric angle (horizontal axis) is 36 degrees (=) as shown in FIG. 180 / L) by a five-phase phase-shifted sine waveform _{P a, P B, P C} , P D, is detected waveform consisting of _{P E} obtained. Also in this case, the position of the peak of the magnetic flux density (vertical axis) on the horizontal axis appears biased to a range of less than half of the electric angle of 360 degrees.

In contrast, the sine wave waveform _P A of the _{five-phase, P B, P C, P} D, offset process each _{P E,} of which, the positive and negative even-numbered corresponding to the magnetic detection element ₂₂ B, 22 _D-derived signal When inverted, as shown in FIG. 9, five-phase sinusoidal waveforms Pp _A , Pp _C , Pp _E , Pp _B , and Pp _D, which are out of phase by 72 degrees at the electrical angle, are obtained. That is, it is possible to obtain a waveform group based on a processed waveform in which the phases are evenly shifted within an electric angle of 360 degrees and peak positions or zero cross points appear at equal intervals.

After that, the a-phase-2 phase conversion unit 34 converts the five processed waveforms into a-phase-2 phase conversion, performs 5-phase-2 phase conversion, and calculates a tangent inverse function for the 2-phase signal to obtain the rotation angle position. Can be detected. By performing the a-phase to two-phase conversion, the fifth-order component of the detection signal, which is an in-phase component, can be removed, and the detection accuracy can be improved.

The positive and negative inversions may be performed alternately in the order in which the magnetic detection elements 22 are arranged. In this modification 1, the positive and negative signals derived from the magnetic detection elements 22 _A , 22 _C , and 22 _E , which correspond to odd numbers, are inverted. You may.

Further, the magnetic detection element 22 may be installed so that the direction of the magnetic flux detected by the magnetic detection element 22 is regularly reversed regardless of the arithmetic processing. For example, in this modification, the magnetic detection elements 22 _B and 22 _D detect the magnetic flux in the radial inward direction as positive, and the magnetic detection elements 22 _A , 22 _C and 22 _E detect the magnetic flux in the radial outward direction as positive. It is installed with different polarities or with the direction of the detection surface changed so that it can be detected as.

With this configuration, even if the positive / negative inversion unit 33 in FIG. 3 is omitted, a five-phase processed waveform in which the electrical angles are deviated by 72 degrees can be obtained simply by performing the DC offset correction process. It is possible. Further, the magnetic detection elements 22 _A , 22 _C and 22 _E detect the magnetic flux in the radial inward direction as positive, and the magnetic detection elements 22 _B and 22 _D detect the magnetic flux in the radial direction as positive. Even when it is configured, it is possible to detect the rotation angle position in the same manner.

Modification example 2.
In the first modification, an example in which five magnetic detection elements are arranged has been described, but in the second modification (second modification), an example in which seven magnetic detection elements are arranged will be described. 10 to 12 are for explaining the configuration and operation of the rotation angle detection device according to the second modification, and FIG. 10 shows the vicinity of the portion where the rotor and the stator of the rotation angle detection device face each other (FIG. 10). FIG. 11 is an enlarged schematic view (corresponding to FIG. 2), and FIG. 11 is a diagram showing a magnetic flux density waveform output from each magnetic detection element to the rotation angle calculation processing unit when seven magnetic detection elements are arranged on the stator. (Corresponding to FIG. 4), FIG. 12 shows that the magnetic flux density waveforms from the seven magnetic detection elements are corrected by the DC offset correction unit, and then the positive and negative inversion units are used to positively and negatively correct the waveforms of the three magnetic detection elements located at even positions. It is a figure (corresponding to FIG. 5) which shows the magnetic flux density waveform which performed the inversion process.

In this modification 2, as shown in FIG. 10, seven magnetic detection elements 22 _A , 22 _B , 22 _C , 22 _D , 22 _E , 22 _F , and 22 _G are evenly arranged in the circumferential direction (the number of arrangement locations L). = 7). Even when the number of elements is n = 7, the magnetic detection elements 22 are arranged at equal intervals of a mechanical angle of 180 / (N × L) degrees with L = n. In that case, the signals output from each magnetic detection element 22 have an interval of 180/7 degrees (= 180 / L) within a range of an electric angle of 154 degrees (<180 degrees). When N = 12, θs is 2.1 degrees and θg is 12.9 degrees.

In the case of such a configuration, as shown in FIG. 11, a seven-phase sine wave whose electrical angle (horizontal axis) is 180/7 degrees out of phase from each of the seven magnetic detection elements 22 _{A to} 22 _G. is detected waveform consisting of waveform _P A to P _G obtained. Also in this case, the position of the peak of the magnetic flux density (vertical axis) on the horizontal axis appears biased to a range of less than half of the electric angle of 360 degrees.

In contrast, the sine wave waveform _P A of the _{7-phase, P B, P C, P} D, P E, P F, and the offset process each _{P G,} of which the even-numbered magnetic detection element ₂₂ B, 22 _D When the positive and negative of the three signals derived from 22 _F are inverted, as shown in FIG. 12, 7-phase sinusoidal waveforms Pp _A , Pp _C , Pp _E , and Pp whose electrical angles are out of phase by 360/7 degrees. _A processed waveform composed of _G , Pp _B , Pp _D , and Pp _F can be obtained. That is, it is possible to obtain a waveform group in which the phases are evenly shifted within the electric angle of 360 degrees and the peak positions or zero cross points appear at equal intervals.

After that, the a-phase-2 phase conversion unit 34 converts the processed waveform for 7 phases into 7-phase-2 phase conversion, and calculates the tangent / inverse function for the 2-phase signal to rotate the rotation angle. The position can be detected. By performing the a-phase to two-phase conversion, the seventh-order component of the detection signal, which is an in-phase component, can be removed, and the detection accuracy can be improved.

Here, when the installation range of the plurality of elements is expanded to an electric angle of 180 to 360 degrees as shown in the background technology, it is disadvantageous for miniaturization as a mechanical configuration. On the other hand, it can be considered that the configuration of the arithmetic processing can be simplified by omitting the selection of the target and the positive / negative inversion processing, or the complexity such as the alternate inversion setting of the positive / negative detection direction can be eliminated. However, when a signal obtained from an element arranged in a range of an electric angle of 180 ° or more is used, it is found that a specific order component cannot be removed and the amplitude at the time of two-phase conversion is different, so that the detection accuracy deteriorates. It was. That is, as in the present application, the installation range of the magnetic detection element 22 is set to an electric angle of less than 180 °, and every other signal is subjected to positive / negative inversion processing in the order of arrangement in the circumferential direction. Not only that, it is also possible to achieve the effect of improving the detection accuracy.

In the rotation angle detection device 1 in which the magnetic detection elements 22 described above are arranged at a mechanical angle of 180 / (N × L) degrees and positive / negative inversion processing is performed every other time, the number n of elements is 3, 5, and 7. Not limited to this, other odd numbers can be applied. A case where the number of arrangements is an even number of 4 or more will be described in the fourth embodiment.

In the rotation angle detection device 1 according to each embodiment of the present application, the rotation angle calculation processing unit 30 is described as, for example, as hardware 300 including a processor 301 and a storage device 302, as shown in FIG. can do. Although not shown, the storage device 302 includes a volatile storage device such as a random access memory and a non-volatile 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 301 executes the program input from the storage device 302. In this case, the program is input from the auxiliary storage device to the processor 301 via the volatile storage device. Further, the processor 301 may output data such as a calculation result to the volatile storage device of the storage device 302, or may store the data in the auxiliary storage device via the volatile storage device.

Embodiment 2.
In the first embodiment, an example is described in which the signals from the magnetic detection elements are arranged in the circumferential direction so as to be inverted every other or detected in the positive and negative directions, but the present invention is limited to this. There is no such thing. In the second embodiment and the third embodiment, an example in which signals having opposite positive and negative signs are output from every other magnetic detection element in the order of arrangement in the circumferential direction will be described.

14 to 16 are for explaining the configuration and operation of the rotation angle detection device according to the second embodiment, and FIG. 14 shows the vicinity of a portion where the rotor and the stator of the rotation angle detection device face each other (FIG. 14 to 16). FIG. 15 is an enlarged schematic view (corresponding to FIG. 2), in which FIG. 15 shows a rotation angle from each magnetic detection element when a magnetic detection element is arranged in each of the magnetic flux generating parts in which three magnets having different polarities are arranged on a stator. A diagram showing the magnetic flux density waveform output to the arithmetic processing unit (corresponding to FIG. 4), and FIG. 16 is a diagram showing the magnetic flux density waveform obtained by DC offset correction processing of the magnetic flux density waveforms from the three magnetic detection elements by the DC offset correction unit. (Corresponding to FIG. 5). The rotation angle calculation processing unit will be described with reference to FIG. 3 used in the first embodiment.

In the rotation angle detecting device 1 according to the second embodiment, as shown in FIG. 14, the magnetic field generating unit 21 is composed of three magnets 21p, 21n, and 21p, and the orientations of the adjacent magnets (21p and 21n) are opposite to each other. It was configured to be. The rotation angle calculation processing unit 30 is the same as the configuration described in the first embodiment except that the positive / negative reversal unit 33 in FIG. 3 is omitted.

In the case where the number of elements is n = 3, and the number of arrangement locations L = n separated in the circumferential direction, the magnetic detection elements 22 _U , 22 _V , and 22 _W have a mechanical angle of 180 / (N × L) degrees in the circumferential direction. The three magnets 21p, 21n, and 21p are arranged inside the radial direction at intervals of. Since the orientation of the magnet 21p in which the magnetic detection elements 22 _U and 22 _W are arranged at both ends is opposite to the magnet 21n in which the central magnetic detection element 22 _V is arranged, the magnetic flux detected by the magnetic detection element 22 _V is opposite. The direction of is opposite to the direction of the magnetic flux detected by the magnetic detection elements 22 _U and 22 _W.

Therefore, as shown in FIG. 15, a sine waveform _P U, _{P W} to be detected by the magnetic sensor ₂₂ U, 22 _W, the sign of the sine waveform _{P V} of the magnetic flux density detected by the magnetic sensing element 22 _V different ing. Therefore, the sinusoidal waveforms P _U , P _V , and P _W are actually out of phase by an electric angle of 60 degrees (180 / L), but as in the case of the positive / negative inversion process of the first embodiment, the P _U , P _W, in the order of _{P V,} manifested as out of phase in electrical angle of 120 degrees.

The obtained sinusoidal waveforms P _U , P _W , and P _V are offset processed, respectively. Then, as shown in FIG. 16, even when the magnetic detection elements 22 are arranged at intervals of 60 degrees (180 / L) of electric angles, the phases are shifted by 120 degrees of electric angles by reversing the orientations of the adjacent magnets. It is possible to obtain a shifted three-phase processing waveform. Then, by converting the obtained three-phase processed waveform into three-phase or two-phase, the third-order component of the detection signal, which is an in-phase component, can be removed, and the detection accuracy can be improved. It is also possible to reduce the size of the device.

In the second embodiment, the case where the number of elements n is 3 has been described for simplification of the description, but the present invention is not limited to this, and any odd number of 3 or more may be used. The same applies to the next embodiment 3.

Embodiment 3.
In the second embodiment, an example in which the positive and negative directions are reversed by arranging magnets having different orientations has been described. In the third embodiment, an example in which the positive and negative directions are reversed by arranging the magnets intermittently will be described. FIG. 17 is an enlarged schematic view of the vicinity of a portion (corresponding to FIG. 2) where the rotor and the stator of the rotation angle detection device according to the third embodiment face each other. Further, FIG. 18 is an enlarged schematic view of the vicinity of a portion (corresponding to FIG. 2) where the rotor and the stator of the rotation angle detection device according to the modified example face each other. The rotation angle calculation unit, the sine wave waveform, and the processed waveform are the same as those described in the second embodiment.

As shown in FIG. 17, the rotation angle detecting device 1 according to the third embodiment is provided with a protruding portion 23p protruding toward the inner peripheral surface 20fi of the stator 20 at an intermediate portion in the circumferential direction of the back surface portion 23. It was. Then, two magnets having the same orientation constituting the magnetic field generating portion 21 are sandwiched in the circumferential direction with the protruding portion 23p of the back surface portion 23. Then, of the magnetic detection elements 22 _U , 22 _V , and 22 _W arranged along the inner peripheral surface 20 fi at intervals of a mechanical angle of 180 / (N × L) degrees in the circumferential direction, 22 _U and 22 _W are , Each of them is located on the magnetic field generating portions 21 at both ends, and 22 _V is located on the protruding portion 23p of the back surface portion 23.

With this configuration, the direction of the magnetic flux detected by the magnetic detection element 22 _V located on the back surface 23 is the direction of the magnetic flux detected by the magnetic detection elements 22 _U and 22 _W located on the magnetic field generating unit 21. Is the opposite. Therefore, as described in FIG. 15 of the second embodiment, the sinusoidal waveform _P U to be detected by the magnetic sensor ₂₂ U, _{22 W, P W} and a sinusoidal waveform of the magnetic flux density detected by the magnetic sensing element 22 _V positive and negative of P _V is different. Further, sine waveform _{P U, P W, P V,} respectively, the phase is shifted by an electrical angle of 60 degrees (180 / L).

The obtained sinusoidal waveforms P _U , P _W , and P _V are offset processed, respectively. Then, as described with reference to FIG. 15 of the second embodiment, even when the magnetic detection elements 22 are arranged at intervals of 60 degrees (180 / L) of electric angles, the orientation of the adjacent magnets is reversed to obtain electricity. It is possible to obtain a three-phase processed waveform whose phase is shifted by 120 degrees. Then, by converting the obtained three-phase processed waveform into three-phase or two-phase, the third-order component of the detection signal, which is an in-phase component, can be removed, and the detection accuracy can be improved. It is also possible to reduce the size of the device.

Modification example.
In the third embodiment, an example in which a protruding portion of a magnetic material is arranged instead of a magnet is described for a magnetic detection element arranged even-numbered in the circumferential direction, but the present invention is not limited to this. In this modification, an example in which a protruding portion of a magnetic material is arranged instead of a magnet will be described with respect to the magnetic detection element arranged at an odd number.

As shown in FIG. 18, the rotation angle detecting device 1 according to the present modification is provided with protruding portions 23p protruding toward the inner peripheral surface 20fi of the stator 20 at both ends of the back surface portion 23 in the circumferential direction. Then, the magnet constituting the magnetic field generating portion 21 is sandwiched between the two protruding portions 23p in the circumferential direction. Then, of the magnetic detection elements 22 _U , 22 _V , and 22 _W arranged along the inner peripheral surface 20 fi at intervals of a mechanical angle of 180 / (N × L) degrees in the circumferential direction, 22 _U and 22 _W are , Each of which is located on the protruding portion 23p of the back surface portion 23 at both ends, and 22 _V is located on the magnet constituting the magnetic field generating portion 21.

With this configuration, the direction of the magnetic flux detected by the magnetic detection element 22 _V located on the magnetic field generation unit 21 is the direction of the magnetic flux detected by the magnetic detection elements 22 _U and 22 _W located on the back surface 23. Is the opposite. Therefore, as described in FIG. 15 of the second embodiment, the sinusoidal waveform _P U to be detected by the magnetic sensor ₂₂ U, _{22 W, P W} and a sinusoidal waveform of the magnetic flux density detected by the magnetic sensing element 22 _V positive and negative of P _V is different. Further, sine waveform _{P U, P W, P V,} respectively, the phase is shifted by an electrical angle of 60 degrees (180 / L).

The obtained sinusoidal waveforms P _U , P _W , and P _V are offset processed, respectively. Then, as described with reference to FIG. 15 of the second embodiment, even when the magnetic detection elements 22 are arranged at intervals of 60 degrees (180 / L) of electric angles, the orientation of the adjacent magnets is reversed to obtain electricity. It is possible to obtain a three-phase processed waveform whose phase is shifted by 120 degrees. Then, by converting the obtained three-phase processed waveform into three-phase or two-phase, the third-order component of the detection signal, which is an in-phase component, can be removed, and the detection accuracy can be improved. It is also possible to reduce the size of the device.

Embodiment 4.
In the first to third embodiments, an example in which the number of elements is odd has been described. In the fourth embodiment, the arrangement when the number of elements is an even number and the selection of the positive / negative inversion processing target will be described. 19 to 21 are for explaining the configuration and operation of the rotation angle detection device according to the fourth embodiment. FIG. 19 is a diagram showing a configuration of a rotor of a rotation angle detection device, FIG. 19A is a cross-sectional view showing a cross section perpendicular to the axial direction of the stator, and FIG. 19B is a surface of the stator facing the rotor, that is, inside. It is a side view of the peripheral surface side. Further, FIG. 20 is a diagram showing a magnetic flux density waveform output from each magnetic detection element to the rotation angle calculation processing unit when two magnetic detection elements are arranged at two locations in the circumferential direction of the stator (FIG. 20). (Corresponding to FIG. 4), FIG. 21 is a diagram (corresponding to FIG. 5) showing the magnetic flux density waveforms obtained by performing DC offset correction processing on the magnetic flux density waveforms from the four magnetic detection elements by the DC offset correction unit. The rotor is the same as described in each of the above-described embodiments. Further, the rotation angle calculation processing unit will be described with reference to FIG. 3 used in the first embodiment.

The rotation angle detection device 1 according to the fourth embodiment describes an example of arranging magnetic detection elements when the number of elements n is an even number of 4 or more, in the case where the number of elements n is four. The number L of the magnetic detection elements arranged in the circumferential direction in the stator 20 was set to 2, which is half of the number n (= 4). Then, as shown in FIG. 19, for example, two magnetic detection elements 22 displaced in the axial direction are arranged at each of the arrangement locations separated in the circumferential direction, and the magnetic detection elements 22 in the same arrangement location are arranged. I tried to reverse the positive and negative of one. The arrangement within the same arrangement location may be shifted in the radial direction, or may be shifted in the circumferential direction as long as it is within the resolution of the detection sensitivity.

Regarding the mechanism for positive / negative inversion, in addition to the arithmetic processing by the positive / negative inversion unit 33 described in the first embodiment, the orientation of the magnetic field generating portion in the circumferential direction shown in the second and third embodiments, or the magnetic material of the magnet. Any mechanism is possible, such as the one in which the replacement of the magnets is replaced in the axial direction. In this example, the two magnetic detection elements 22 mentioned as application examples in the first embodiment will be illustrated with a configuration in which the directions of the positive magnetic fluxes are different. Specifically, for example, in FIG. 19B, the magnetic detection elements 22 _A and 22 _C located on the upper side in the axial direction detect the magnetic flux in the radial direction as positive, and the magnetic detection elements located on the lower side in the axial direction. 22 _B and 22 _D are configured to detect the magnetic flux outward in the radial direction as positive.

Then, assuming that the number of arrangement points L = 2, the interval θw of each arrangement position in the circumferential direction is a mechanical angle of 180 / (N × L), and the electric angle between adjacent arrangement positions in the circumferential direction is 180 / L (= 90). Degree). However, as described above, since the two magnetic detection elements 22 are arranged at the positions of the same electric angle, two signals whose positive and negative directions are inverted can be obtained from the same electric angle.

Therefore, as shown in FIG. 20, as well as the number of the magnetic detection elements 22, to obtain four sine waveform, sine waveform _P A to be detected by the magnetic sensor ₂₂ A, 22 _C, and _{P C,} magnetic The positive and negative of the magnetic flux density detected by the detection elements 22 _B and 22 _D are different. Further, sine waveform P _A and P _B are positive and negative reversed at the same electric angle, also sinusoidal waveform P _C and P _D is positive or negative at the same electrical angle is reversed. Then, the sine waveform _{P A} and _{P B,} sine waveform _{P C} and _{P D} are phase with an electrical angle of 90 degrees (180 / L).

The obtained sinusoidal waveforms P _{A to} P _D are each offset processed. Then, as shown in FIG. 21, even when the magnetic detection elements 22 are arranged at intervals of 90 degrees (= 180 / L) within an electrical angle of 180 degrees in total, the phases are shifted by 90 degrees of electrical angles. _A processed waveform composed of four-phase sinusoidal waveforms Pp _A , Pp _C , Pp _B , and Pp _D can be obtained. Then, by converting the obtained 4-phase processed waveform into 4-phase or 2-phase, the fourth-order component of the detection signal, which is an in-phase component, can be removed, and the detection accuracy can be improved. It is also possible to reduce the size of the device.

Although not shown, for example, if the number of elements n is 6, 8, 10, ..., The number of arrangement locations L is 3, 4, 5, ..., Which is half the number of elements, respectively. Set. The locations adjacent to each other in the circumferential direction are arranged at intervals of 180 / (N × L) degrees at a mechanical angle θw, and the mechanical angle θg falls within the range of less than 180 / L degrees. At that time, the electric angle (= 360 / L) becomes 60 degrees, 45 degrees, 36 degrees, ..., And the electric angle range falls within the range of 120 degrees, 135 degrees, and 144 degrees, respectively. In this example, since there are two arrangement locations, θg = θw, but there is a relationship of θg = θw × (L-1).

That is, the magnetic detection element 22 is arranged so that the number of arrangement locations L when the number of elements n is an even number is half the number of elements, and the number of arrangement locations L when the number of elements n is an odd number matches the number of elements n. As a result, regardless of whether the number of elements n is odd or even, the magnetic detection element 22 may be arranged at a position where the mechanical angle 180 / N is divided by the number of arrangement locations L. Then, if a mechanism is provided such that the signals of the magnetic detection elements 22 that are regularly selected are positively and negatively inverted in each of the odd number case and the even number case, the rotation angle detection device 1 of the present application that exerts the above-mentioned effect can be obtained. Can be done.

Further, while various exemplary embodiments and examples are described in the present application, the various features, embodiments, and functions described in one or more embodiments are specific embodiments. It is not limited to the application of, but can be applied to the embodiment alone or in various combinations. Therefore, innumerable variations not illustrated are envisioned within the scope of the techniques disclosed herein. For example, it is assumed that at least one component is modified, added or omitted, and further, at least one component is extracted and combined with the components of other embodiments.

For example, an example is shown in which the outer diameter of the uneven portion 12 changes so as to draw a sine wave, but the present invention is not limited to this, and the diameter changes at a constant cycle with rotation within a detectable level range. It may be in the shape of a saw blade, for example.

As described above, according to the rotation angle detection device 1 according to each embodiment, the uneven portion of the magnetic material is rotatably supported around the rotation axis Xr and the diameter of the outer peripheral surface 10fo changes N times periodically. The rotor 10 having the 12 and the magnetic field generating portion 21 that faces the outer peripheral surface 10fo of the rotor 10 at intervals and generates a magnetic field between the rotor 10 and the uneven portion 12, and 180 degrees in the mechanical angle along the circumferential direction. Is arranged in a range less than the value divided by N, and is based on a detector 20 having an element group composed of three or more magnetic detection elements 22 for detecting the generated magnetic field, and a detection signal from the element group. , A part of the element group according to the rotation angle calculation processing unit 30 for calculating the rotation angle of the rotor 10 and the number of elements n which is the number of elements (magnetic detection element 22) constituting the element group. Since the element is selected and the positive / negative reversal mechanism for reversing the detection signal from the selected element is provided, it is possible to obtain the rotation angle detection device 1 which is compact and can accurately detect the rotation angle.

In particular, assuming that the number of arrangement positions set in the circumferential direction (the number of arrangement locations L) of the element group is an integer of 2 or more, the angle between the adjacent magnetic detection elements 22 in the circumferential direction about the rotation axis Xr is a machine. If the angle is set to a value (= 180 / (N × L)) obtained by dividing N by 180 degrees by the product of N and the set number (number of placement points L), peaks or zero cross points will appear at equal intervals and rotate more accurately. The angle can be detected.

When the number of elements n is an odd number, the set number (number of arrangement points L) is matched with the number of elements n, one element constituting the element group is arranged at each arrangement position, and the positive / negative inversion mechanism is Among the elements (magnetic detection element 22) constituting the element group, every other element (for example, even-th or odd-number) is selected as a part of the elements to be inverted in the order of arrangement in the circumferential direction. With such a configuration, a waveform that is evenly out of phase within an electric angle of 360 degrees can be obtained, and more reliable and accurate detection of the rotation angle becomes possible.

Alternatively, when the number of elements n is an even number, the set number (number of arrangement points L) is set to half of the number of elements n, and two elements (magnetic detection elements 22) constituting the element group are provided at each of the arrangement positions. If the positive / negative inversion mechanism is configured to select one of the two elements arranged at each of the arrangement positions as a part of the elements to be inverted, the electric angle is 360 degrees. A waveform that is evenly out of phase can be obtained, and more reliable and accurate detection of the rotation angle becomes possible.

The rotation angle calculation processing unit 30 is an offset processing unit (DC offset calculation unit) that offsets the DC component of the detection signal output from each element (magnetic detection element 22) constituting the element group based on the reference value. 31. DC offset correction unit 32), assuming that a signal with the same number of phases a as the number of elements n can be obtained, a-phase-two-phase conversion is performed from each offset-processed signal (processed waveform) to obtain a two-phase signal. Since the a-phase-2 phase conversion unit 34 and the angle calculation unit 35 that calculates the forward / reverse function of the two-phase signal to detect the rotation angle are provided, the detection signal detected by the magnetic detection element 22 is surely provided. It is possible to remove the a-th order component of the detection signal and improve the detection accuracy.

As a positive / negative inversion mechanism, if the rotation angle calculation processing unit 30 is provided with a positive / negative inversion unit 33 that performs positive / negative inversion processing of the detection signal from the selected element by calculation, the positive / negative inversion processing can be performed on the software. Can be easily done.

As a positive / negative inversion mechanism, for example, if the detection direction of another element is inverted with respect to the detection direction of the selected element and the element (magnetic detection element 22) constituting the element group is arranged, there is no arithmetic processing. , It is possible to obtain a signal in which the positive and negative of the element selected from the beginning are inverted.

Further, for example, the magnetic field generating unit 21 is composed of a plurality of magnets (21n, 21p) arranged on the outer diameter side of three or more magnetic detection elements 22, and as a positive / negative inversion mechanism, an element (magnetic detection) constituting the element group. Of the elements 22), the orientation of the magnet (for example, 22n) arranged on the outer diameter side of the selected element is reversed with respect to the orientation of the magnet (for example, 22p) arranged on the outer diameter side of the other element. Even in the case of the above configuration, it is possible to obtain a signal in which the positive and negative of the element selected from the beginning are inverted without any arithmetic processing.

The stator 20 is provided with a back surface portion 23 of a magnetic material that covers the outer diameter side of the magnetic field generating portion 21, and as a positive / negative reversal mechanism, the element selected from the elements (magnetic detection element 22) constituting the element group is used. Is such that the magnets constituting the magnetic field generating portion 21 are arranged, and the protruding portion 23p of the back surface portion 23 protruding from the outer diameter side to the inner peripheral surface 20fi side is arranged on the outer diameter side of the other element. Even in the case of configuration, it is possible to obtain a signal in which the positive and negative of the element selected from the beginning are inverted without any arithmetic processing.

1: Rotation angle detector, 10: Rotor, 10fo: Outer surface, 12: Concavo-convex part, 20: Stator, 20fi: Inner peripheral surface, 21: Magnetic field generator (positive / negative reversal mechanism), 21n, 21p: Magnet ( Positive / negative inversion mechanism), 22: Magnetic detection element, 23: Back surface, 23p: Projection (positive / negative inversion mechanism), 30: Rotation angle calculation processing unit, 31: DC offset calculation unit (offset processing unit), 32: DC offset Correction unit (offset processing unit), 33: Positive / negative inversion unit (positive / negative inversion mechanism), 34: a-phase-2 phase conversion unit, a: number of phases, L: number of arrangement points (number of arrangement positions), N: number of irregularities , N: Number of elements (number), Xr: Rotation axis.

Claims (9)

A rotor that is rotatably supported around a rotation axis and has an uneven portion of a magnetic material whose outer peripheral surface diameter changes N times periodically.
A magnetic field generating portion that faces the outer peripheral surface of the rotor at a distance and generates a magnetic field between the rotor and the uneven portion, and a value less than 180 degrees divided by N at a mechanical angle along the circumferential direction. A stator, which is arranged in a range of less than 180 degrees in electrical angle , and has an element group composed of three or more magnetic detection elements for detecting the generated magnetic field.
A rotation angle calculation processing unit that calculates the rotation angle of the rotor based on the detection signals from each element of the element group, and
A positive / negative inversion mechanism that selects some elements in the element group according to the number of elements, which is the number of magnetic detection elements in the element group, and inverts the detection signal from the selected elements.
A rotation angle detection device characterized by being equipped with. Assuming that the set number of arrangement positions of the element group in the circumferential direction is an integer of 2 or more,
The first aspect of claim 1, wherein the angle between adjacent arrangement positions in the circumferential direction about the rotation axis is set to a value obtained by dividing 180 degrees by the product of N and the set number in the mechanical angle. Rotation angle detector. When the number of elements is odd,
The set number is matched with the number of elements, and one element constituting the element group is arranged at each of the arrangement positions.
Moreover, the positive / negative inversion mechanism is
The rotation angle detecting device according to claim 2, wherein every other element is selected as a part of the elements in the arrangement order in the circumferential direction among the elements constituting the element group. When the number of elements is even,
The set number is set to half of the number of elements, and two elements constituting the element group are arranged at each of the arrangement positions.
Moreover, the positive / negative inversion mechanism is
The rotation angle detecting device according to claim 2, wherein one of the two elements arranged at each of the arranged positions is selected as a part of the elements. The rotation angle calculation processing unit includes
An offset processing unit that offsets the DC components of the detection signals output from each of the elements that make up the element group based on the reference value.
Assuming that a signal having the same number of phases a as the number of elements can be obtained, the a-phase-2 phase converter for obtaining a two-phase signal by performing a-phase-2 phase conversion from each offset-processed signal, and
An angle calculation unit that calculates the tangent and inverse functions of the two-phase signal and detects the rotation angle.
The rotation angle detecting device according to any one of claims 1 to 4, wherein the rotation angle detecting device is provided. As the positive / negative reversal mechanism,
The method according to any one of claims 1 to 5, wherein the rotation angle calculation processing unit is provided with a positive / negative inversion unit that performs positive / negative inversion processing of a detection signal from the selected element by calculation. Rotation angle detector. As the positive / negative reversal mechanism,
The invention according to any one of claims 1 to 5, wherein the elements constituting the element group are arranged by inverting the detection direction of the other element with respect to the detection direction of the selected element. Rotation angle detector. The magnetic field generating portion is composed of a plurality of magnets arranged on the outer diameter side of the element group.
As the positive / negative reversal mechanism,
Among the elements constituting the element group, the orientation of the magnet arranged on the outer diameter side of the selected element is reversed with respect to the orientation of the magnet arranged on the outer diameter side of the other element. The rotation angle detecting device according to any one of claims 1 to 5. The stator is provided with a back surface portion of a magnetic material that covers the outer diameter side of the magnetic field generating portion.
As the positive / negative reversal mechanism,
Among the elements constituting the element group, magnets constituting the magnetic field generating portion are arranged on the outer diameter side of the selected element, and the outer diameter side of the other elements is from the outer diameter side to the inner circumference. The rotation angle detecting device according to any one of claims 1 to 5, wherein the protruding portion of the back surface portion projecting to the surface side is arranged.

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