Magnetic encoder

Abstract

To achieve functional redundancy in a high-resolution magnetic encoder detecting the absolute angular position in multiple rotations, to avoid a situation where a failure cannot be detected and correct angle information cannot be output.SOLUTION: A magnetic encoder 1A performs cross-check processing of verifying whether first multi-rotation information and second multi-rotation information are normal in which a first multi-rotation sensor unit 20A and a second multi-rotation sensor unit 20B correspond respectively to the cumulative rotation number. The magnetic encoder performs cross-check processing of verifying whether a first one-revolution angle and a second one-revolution angle are normal in which a first one-revolution sensor unit 40A and a second one-revolution sensor unit 40B are respectively at an angular position within a range of one revolution. After the verification, the magnetic encoder integrates all the multi-rotation information and one-revolution angles to calculate the absolute angular position in multiple rotation.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a magnetic encoder for detecting rotation. [Background technology]

[0002] Encoders that detect absolute angular positions over multiple rotations, including not only the angular position but also the number of rotations, are mounted on various devices such as motors. In the rotary encoder described in Patent Document 1, a two-pole first magnet, with one N pole and one S pole magnetized, is arranged on the rotation axis of a rotating body, and a multi-pole second magnet, with N poles and S poles magnetized alternately in the circumferential direction, is arranged to surround the first magnet. The absolute angular position over multiple rotations is detected based on the outputs of a magnetic resistance element and two Hall elements (first magnetic sensing unit) facing the two-pole first magnet, and the output of a magnetic resistance element (second magnetic sensing unit) facing the multi-pole second magnet. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6877168 Summary of the Invention [Problem to be solved by the invention]

[0004] In various devices equipped with an encoder, a malfunction of the encoder (no output of angle information) can be detected as a failure, but if the encoder continues to output incorrect angle information while still functioning as an encoder, it cannot be detected as a failure and no action can be taken because it is not possible to determine whether the angle information is correct. Therefore, there is a demand for an encoder that can detect when angle information is incorrect and output correct angle information.

[0005] In response to such demands, it is conceivable to provide multiple encoders for the same rotating body, and detect failures by comparing the angle information from the multiple encoders, so that even if one of them fails, the angle information from the other encoder can be output (redundancy). However, simply providing two sets of encoders with the same structure would mean installing twice as many components, making the structure of the device more complex and larger, and resulting in higher costs. In particular, optical encoders are often used for high-resolution encoders, but when optical encoders are made redundant, it is difficult to make them smaller and simpler, and costs increase significantly.

[0006] On the other hand, as in Patent Document 1, an encoder that detects the absolute angular position over multiple rotations needs to count the number of rotations, but in order to correctly count the cumulative number of rotations (multiple rotation information), it is necessary to maintain a state in which rotation can always be detected when the rotating body moves, and to continue counting reliably.

[0007] In view of the above problems, the present invention proposes an encoder that can detect an absolute angular position in a magnetic encoder that detects an absolute angular position over multiple rotations, and that provides redundancy with a simple, low-cost configuration to avoid a situation in which a failure cannot be detected and correct angle information cannot be output. [Means for solving the problem]

[0008] In order to solve the above problems, a first aspect of the present invention is a magnetic encoder for detecting an absolute angular position of a rotating body, comprising: two sets of multi-rotation sensor units for detecting the rotation of the rotating body; two sets of one-rotation sensor units for detecting a one-rotation angle which is an angular position within a range of one rotation of the rotating body; a first magnet having a pair of N and S poles magnetized; and a second magnet having multiple pairs of N and S poles magnetized alternately in a circumferential direction. and a ring-shaped second magnet having a magnetized second track and arranged coaxially with the first magnet, wherein the two sets of multi-rotation sensor units each include a first multi-rotation sensor unit having a magnetic generating element facing the first magnet and calculating first multi-rotation information corresponding to the accumulated number of rotations of the rotating body based on a detection signal of a current generated by the magnetic generating element, and a second multi-rotation sensor unit facing the first magnet and calculating second multi-rotation information corresponding to the accumulated number of rotations of the rotating body based on outputs of first and second magnetic detection elements which are separated by a mechanical angle of 90°, wherein each of the first multi-rotation sensor unit and the second multi-rotation sensor unit performs a cross-check process to verify whether the first multi-rotation information and the second multi-rotation information are normal, and The one-rotation sensor unit includes a first one-rotation sensor unit that calculates a first one-rotation angle based on outputs of a first magnetic sensing element facing the second magnet, the first and second magnetic detection elements or third and fourth magnetic detection elements facing the first magnet and separated by 90° mechanical angle, and the second magnetic sensing element facing the first magnet, and a second one-rotation sensor unit that calculates a second one-rotation angle based on outputs of a first magnetic detection element group consisting of three or more magnetic detection elements including fifth, sixth and seventh magnetic detection elements facing the first magnet and arranged in the circumferential direction, and is characterized in that the first one-rotation sensor unit and the second one-rotation sensor unit each perform a cross-check process to verify whether the first one-rotation angle and the second one-rotation angle are normal.

[0009] In order to solve the above problem, a second aspect of the present invention is a magnetic encoder for detecting an absolute angular position of a rotating body, the encoder comprising: two sets of multi-rotation sensor units for detecting rotation of the rotating body; two sets of one-rotation sensor units for detecting a one-rotation angle which is an angular position within a range of one rotation of the rotating body; a first magnet having a pair of N poles and S poles magnetized; and an annular second magnet having a second track in which multiple pairs of N poles and S poles are magnetized alternately in a circumferential direction and arranged coaxially with the first magnet, the two sets of multi-rotation sensor units comprising: a first multi-rotation sensor unit having a magnetic power generation element facing the first magnet, the first multi-rotation sensor unit calculating first multi-rotation information corresponding to the accumulated number of rotations of the rotating body based on a detection signal of a current generated by the magnetic power generation element; and a second multi-rotation sensor unit calculating second multi-rotation information corresponding to the accumulated number of rotations of the rotating body based on outputs of first and second magnetic detection elements facing the first magnet and spaced apart by 90° in mechanical angle, the first multi-rotation sensor unit and a first multi-rotation sensor unit in front of the first multi-rotation sensor unit. Each of the second multi-rotation sensor units performs a cross-check process to verify whether the first multi-rotation information and the second multi-rotation information are normal, and the two sets of one-rotation sensor units include a first one-rotation sensor unit that calculates a first one-rotation angle based on the output of a first magnetic detection element group consisting of three or more magnetic detection elements including a first magnetic sensing element facing the second magnet, and third, fourth and fifth magnetic detection elements that face the first magnet and are arranged circumferentially, and a second one-rotation sensor unit that calculates a second one-rotation angle based on the output of a second magnetic sensing element facing the first magnet, and the first and second magnetic detection elements or sixth and seventh magnetic detection elements that are different from the first and second magnetic detection elements and are separated by 90° mechanical angle, and the first one-rotation sensor unit and the second one-rotation sensor unit each perform a cross-check process to verify whether the first one-rotation angle and the second one-rotation angle are normal.

[0010] In order to solve the above problem, a third aspect of the present invention is a magnetic encoder that detects an absolute angular position of a rotating body, the encoder comprising: two sets of multi-rotation sensor units that detect rotation of the rotating body; two sets of one-rotation sensor units that detect a one-rotation angle that is an angular position within a range of one rotation of the rotating body; an annular first magnet having a first track on which a pair of N poles and S poles are magnetized; an annular second magnet having a second track on which multiple pairs of N poles and S poles are magnetized alternately in the circumferential direction and arranged coaxially with the first magnet; and an annular third magnet having a pair of N poles and S poles magnetized and arranged coaxially with the first magnet and the second magnet, the two sets of multi-rotation sensor units comprising a first magnetic generating element facing the first magnet, a first multi-rotation sensor unit that calculates first multi-rotation information corresponding to the accumulated number of rotations of the rotating body based on a detection signal of a current generated in the first magnetic generating element, and a second magnetic generating element facing the first magnet, and a second multi-rotation sensor unit that calculates second multi-rotation information corresponding to the cumulative number of rotations of the rotating body based on a detection signal of a current generated by the second magnetic power generating element, wherein each of the first multi-rotation sensor unit and the second multi-rotation sensor unit performs a cross-check process to verify whether the first multi-rotation information and the second multi-rotation information are normal or not, and the two sets of single-rotation sensor units each include three or more magnetic sensors including a first magnetic sensing element facing the second magnet, and first, second and third magnetic sensing elements facing the third magnet and aligned in a circumferential direction. The magnet is provided with a first one-rotation sensor unit that calculates a first one-rotation angle based on the output of a first magnetic detection element group consisting of detection elements, and a second one-rotation sensor unit that calculates a second one-rotation angle based on the output of a second magnetic detection element group consisting of three or more magnetic detection elements including fourth, fifth and sixth magnetic detection elements that face the third magnet and are arranged circumferentially, and is characterized in that the first one-rotation sensor unit and the second one-rotation sensor unit each perform a cross-check process to verify whether the first one-rotation angle and the second one-rotation angle are normal.

[0011] According to each aspect of the present invention, two systems of multi-rotation sensor units each calculate multi-rotation information and perform a cross-check process to mutually verify whether the calculated multi-rotation information is normal. Similarly, two systems of one-rotation sensor units that detect one-rotation angles are provided, and similarly perform a cross-check process. In this way, by constructing a redundant system with two systems of detection elements and calculation units for outputting absolute angular positions, even if a failure occurs, it is possible to calculate a correct absolute angular position from the output of the system that is not faulty. Therefore, it is possible to avoid a situation in which a failure cannot be detected and an abnormal absolute angular position continues to be output.

[0012] According to each aspect of the present invention, the redundant system is configured entirely with magnetic detection mechanisms, so that the configuration can be simplified, miniaturized, and reduced in cost compared to the case where an optical angle detection mechanism is also used. In addition, there is an advantage that malfunctions due to dirt are unlikely to occur and durability is high. Furthermore, since at least one system of the multi-rotation sensor unit is equipped with a magnetic power generation element, at least one system can continue to update multi-rotation information even without a battery or external power supply. In addition, in the third aspect of the present invention, since both of the two multi-rotation sensor units are equipped with a magnetic power generation element, the correct absolute angle position can be output without the burden of replacing batteries.

[0013] In a second aspect of the present invention, the magnet holder has an annular magnet holding part centered on the rotation axis of the rotor, the second magnet is disposed on the outer periphery of one surface of the magnet holding part, the third magnet is disposed on the inner periphery of the one surface, the first magnet is disposed on the other surface of the magnet holding part, the first magnetic sensing element, the first, second and third magnetic detection elements, and the fourth, fifth and sixth magnetic detection elements are disposed on a first substrate facing the one surface, and the first magnetic power generation element and the second magnetic power generation element are disposed on a second substrate facing the other surface. In this way, by disposing magnets on the front and back of the magnet holding part and having the magnetic power generation element and the magnetic sensing element face the magnet holding part from the opposite side, the detection mechanism can be made simple and compact. In addition, since the detection element is not disposed on the rotation axis, it is possible to accommodate a hollow shaft.

[0014] In each aspect of the present invention, an aspect can be adopted in which the first multi-rotation sensor unit, the second multi-rotation sensor unit, the first single-rotation sensor unit, and the second single-rotation sensor unit are connected to a management and supervision unit, and the management and supervision unit includes an absolute angle position integration calculation unit that calculates the absolute angle position based on the first multi-rotation information, the second multi-rotation information, the first single-rotation angle, and the second single-rotation angle.

[0015] Alternatively, in each aspect of the present invention, one of the first one-rotation sensor unit and the second one-rotation sensor unit is an absolute angle position integrator that calculates the absolute angle position based on the first multiple-rotation information, the second multiple-rotation information, the first one-rotation angle, and the second one-rotation angle. It is possible to adopt an embodiment including a sum calculation unit. In this way, the unit that calculates the multiple rotation information and the one-rotation angle can be used as the unit that calculates the absolute angle position, thereby simplifying the configuration and reducing costs.

[0016] In each aspect of the present invention, it is preferable to include a nonvolatile memory that stores the first multi-rotation information and updates the first multi-rotation information by a current generated by a magnetic power generating element, and the absolute angle position integration calculation unit calculates the absolute angle position based on the first multi-rotation information read from the nonvolatile memory at startup. In this way, even if the rotating body moves while power is not supplied, the number of rotations will not become unknown, and an accurate absolute angle position can be output at startup.

[0017] In each aspect of the present invention, the second magnetic sensitive element is a magnetoresistance effect element having a magnetoresistance pattern of phase A and a magnetoresistance pattern of phase B having a phase difference of 90°, the second tracks are arranged in two rows in the radial direction, the positions of the S pole and the N pole of the adjacent second tracks are shifted by one pole in the circumferential direction, and the second magnetic sensitive element is preferably opposed to the boundary between the adjacent second tracks. In this way, the magnetoresistance effect element is disposed in a rotating magnetic field whose direction changes in the in-plane direction of each track, thereby improving the detection accuracy. Effect of the Invention

[0018] According to the present invention, a redundant system is constructed by providing two systems each of a sensor unit for detecting multiple rotation information and a sensor unit for detecting one rotation angle, so that it is possible to avoid a situation in which correct angle information cannot be output due to failure not being detected. In addition, since it is configured entirely with a magnetic detection mechanism, the configuration can be simplified, miniaturized, and reduced in cost, and the configuration is highly durable and less prone to malfunction due to dirt. [Brief description of the drawings]

[0019] [Figure 1] 1 is a configuration diagram and a functional block diagram of a main part of a magnetic encoder according to a first embodiment. [Diagram 2] FIG. 11 is a configuration diagram and a functional block diagram of a fourth modified example of the first embodiment. [Diagram 3] FIG. 11 is a configuration diagram and a functional block diagram of a main part of a magnetic encoder according to a second embodiment. [Figure 4] FIG. 11 is a configuration diagram and a functional block diagram of a main part of a magnetic encoder according to a third embodiment. [Diagram 5] 1 is a cross-sectional view showing a main part of a specific example of a magnetic encoder according to a first embodiment. [Figure 6] FIG. 2 is an exploded perspective view showing a main part of the specific example of the magnetic encoder of the first embodiment, as viewed from the other side in the rotation axis direction (L2 direction). [Figure 7] 1 is an exploded perspective view showing a main part of a specific example of a magnetic encoder according to a first embodiment, as viewed from one side in the direction of the rotation axis (L1 direction). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] An embodiment of a magnetic encoder according to the present invention will be described below. The magnetic encoder according to the present invention is a multi-rotation absolute angular position encoder that can know the number of rotations from a predetermined origin position and the current angular position.

[0021] In this specification, the configuration of the magnetic encoder according to the present invention will be described, focusing on the specific configuration of its main parts, namely the magnet and magnet holder, various elements that detect changes in the magnetic field, and the substrate on which these are arranged, but descriptions of other parts (such as the outer case) will be omitted.

[0022] 1, 2, 3, and 4 are respectively a configuration diagram (arrangement of magnets and elements) and a functional block diagram of the main parts of a magnetic encoder according to the present invention. FIG. 1 is a configuration diagram and a functional block diagram of the main parts of a magnetic encoder 1A of embodiment 1. FIGS. 5, 6, and 7 are explanatory diagrams showing the main parts of a specific example of the magnetic encoder 1A of embodiment 1. FIG. 5 is a cross-sectional view showing the main parts of a specific example of the magnetic encoder 1A of embodiment 1. FIG. 6 is a cross-sectional view showing the main parts of a specific example of the magnetic encoder 1A of embodiment 1. 7 is an exploded perspective view showing a main part of a specific example of the magnetic encoder 1A of the embodiment 1, as viewed from the other side in the rotation axis direction (L2 direction). FIG. 7 is an exploded perspective view showing a main part of a specific example of the magnetic encoder 1A of the embodiment 1, as viewed from one side in the rotation axis direction (L1 direction).

[0023] (Embodiment 1) The magnetic encoder 1A of the first embodiment measures a rotating body 2 such as a rotating shaft of a motor. As shown in FIG. 1, the magnetic encoder 1A includes a magnet holder 3 fixed to the rotating body 2, and a first magnet 11 and a second magnet 12 fixed to the magnet holder 3. The first magnet 11 is a disk-shaped permanent magnet. The second magnet 12 is an annular permanent magnet surrounding the outer periphery of the first magnet 11. The first magnet 11 and the second magnet 12 are arranged coaxially with the rotation axis L of the rotating body 2 as the center. As shown in FIG. 1 and FIG. 5, the magnet holder 3 includes a cylindrical shaft portion 31 and an annular magnet holding portion 32 expanding from the shaft portion 31 to the outer periphery. The shaft portion 31 extends in the axial direction of the rotation axis L. The magnet holding portion 32 is arranged at the end of one side L1 in the axial direction of the shaft portion 31 (see FIG. 5). The shaft portion 31 is fixed to the rotating shaft (rotating body 2) of the motor by, for example, a set screw.

[0024] The first magnet 11 and the second magnet 12 are disposed on one surface 33 of a magnet holder 32. The one surface 33 faces one side L1 in the axial direction, and the other surface 34 of the magnet holder 32 faces the other side L2 in the axial direction (see FIG. 5). The magnetic encoder 1A includes a first substrate 35 that faces the one surface 33 from the one side L1 in the axial direction.

[0025] As shown in FIG. 1 and FIG. 5, the first magnet 11 is disposed at the center of one surface 33 of the magnet holder 32. The first magnet 11 is magnetized with one N pole and one S pole, and its center coincides with the rotation axis L. The second magnet 12 is disposed on the outer periphery of one surface 33 of the magnet holder 32. The second magnet 12 has an annular second track T2 in which multiple pairs of N poles and S poles are magnetized alternately in the circumferential direction, and its center coincides with the rotation axis L. The second tracks T2 are arranged in two rows in the radial direction. The positions of the N poles and S poles of the radially adjacent second tracks T2 are shifted by one pole in the circumferential direction. The second magnet 12 is magnetized with, for example, 128 pairs of N poles and S poles alternately in the circumferential direction. The number of N poles and S poles may be a number other than 128 pairs.

[0026] The magnetic encoder 1A calculates multiple rotation information corresponding to the cumulative number of rotations of the rotating body 2 by detecting the magnetic field of the first magnet 11. Meanwhile, the magnetic field of the first magnet 11 and the second magnet 12 is detected to calculate the angular position within one rotation of the rotating body 2 (hereinafter referred to as one rotation angle). Then, the multiple rotation information and the one rotation angle are combined to calculate the absolute angular position of multiple rotations.

[0027] The magnetic encoder 1A includes a first multi-rotation sensor unit 20A and a second multi-rotation sensor unit 20B as multi-rotation sensor units that calculate multi-rotation information. The first multi-rotation sensor unit 20A and the second multi-rotation sensor unit 20B each calculate multi-rotation information. Hereinafter, the multi-rotation information calculated by the first multi-rotation sensor unit 20A is referred to as the first multi-rotation information, and the multi-rotation information calculated by the second multi-rotation sensor unit 20B is referred to as the second multi-rotation information. Each of the first multi-rotation sensor unit 20A and the second multi-rotation sensor unit 20B performs a cross-check process to compare the first multi-rotation information with the second multi-rotation information and verify whether each piece of multi-rotation information is normal.

[0028] The magnetic encoder 1A includes a first one-rotation sensor unit 40A and a second one-rotation sensor unit 40B as one-rotation sensor units that calculate a one-rotation angle. The first one-rotation sensor unit 40A and the second one-rotation sensor unit 40B each calculate a one-rotation angle. Hereinafter, the one-rotation angle calculated by the first one-rotation sensor unit 40A will be referred to as the first one-rotation angle, and the one-rotation angle calculated by the second one-rotation sensor unit 40B will be referred to as the second one-rotation angle. The first one-rotation sensor unit 40A and the second one-rotation sensor unit 40B each calculate a first one-rotation angle and a second one-rotation angle. A cross-check process is performed to verify whether each rotation angle is normal by comparing it with the rotation angle.

[0029] (First multi-rotation sensor unit) 1, the first multi-rotation sensor unit 20A includes a magnetic generating element W overlapping with the first magnet 11 from one side L1 in the axial direction, a microcontroller unit 21A connected to the magnetic generating element W, and a first non-volatile memory 22A. The first multi-rotation sensor unit 20A may include configurations other than those described above. The magnetic generating element W is mounted on a first substrate surface 35a facing one side l1 in the axial direction of the first substrate 35 (see FIG. 5).

[0030] In the first multi-rotation sensor unit 20A, the magnetic generating element W is a magnetosensitive wire such as a Wiegand wire. The Wiegand wire exhibits the large Barkhausen effect (Wiegand effect) when a magnetic field changes. The Wiegand wire is an element in which a coil is wound around a ferromagnetic wire, and as the first magnet 11 rotates, a pulse-like current is generated in the coil when the coil passes the position where the N pole and S pole of the first magnet 11 switch. At this time, the direction of the current changes depending on the direction before and after the reversal of the magnetic field. Therefore, the direction of the current changes depending on the rotation direction of the rotor 2.

[0031] The microcontroller unit 21A includes a multi-rotation information generating section 23A that performs calculations such as counting the number of rotations based on the output of the magnetic generating element W. For example, the multi-rotation information generating section 23A performs a process of increasing or decreasing a counter value based on a pulsed current and a signal corresponding to its direction, and generates multi-rotation information (e.g., a counter value) corresponding to the accumulated number of rotations of the rotating body 2. The microcontroller unit 21A performs a process of storing the multi-rotation information in the first non-volatile memory 22A using the current from the magnetic generating element W. The first multi-rotation sensor section 20A detects the rotation of the rotating body 2 even if the power supply from the outside or the battery is stopped, and the multi-rotation information (first multi-rotation information) stored in the first non-volatile memory 22A is updated.

[0032] (Second multi-rotation sensor part) The second multi-rotation sensor unit 20B includes magnetic detection elements H1 and H2 that face the first magnet 11 from one side L1 in the axial direction, and a microcontroller unit 21B that is connected to the magnetic detection elements H1 and H2. The magnetic detection elements H1 and H2 are Hall elements. The magnetic detection elements H1 and H2 are disposed at positions that are shifted by 90° in mechanical angle in the phase of rotation about the rotation axis L. The second multi-rotation sensor unit 20B may include configurations other than those described above. The magnetic detection elements H1 and H2 are mounted on a second substrate surface 35b that faces the other side L2 in the axial direction of the first substrate 35.

[0033] The microcontroller unit 21B includes a multiple rotation information generating unit 23B that performs calculations such as counting the number of rotations based on the output of the magnetic detection elements H1 and H2. As described above, the first magnet includes a pair of magnetic pole pairs. Therefore, the magnetic detection elements H1 and H2 output one period of rectangular wave signals that are out of phase with each other by 90° while the rotor 2 rotates once. The multiple rotation information generating unit 23B performs processing such as increasing or decreasing the count value in accordance with the change in this output, and generates multiple rotation information (e.g., a counter value) corresponding to the accumulated number of rotations of the rotor 2.

[0034] (First rotation sensor part) As shown in Fig. 1, the first one-rotation sensor section 40A includes a first magnetic sensing element MR1 facing the second magnet 12 from one side L1 in the axial direction, a second magnetic sensing element MR2 facing the center of the first magnet 11 from one side L1 in the axial direction, magnetic detection elements H3 and H4 facing the outer periphery of the first magnet 11 from one side L1 in the axial direction, and a microcontroller unit 41A connected to the first magnetic sensing element MR1, the second magnetic sensing element MR2, and the magnetic detection elements H3 and H4. The second multi-rotation sensor section 20B may include configurations other than those described above. The microcontroller unit 41A functions as a position calculation section that calculates one rotation angle using the output of each of the above elements.

[0035] The first magnetic sensing element MR1, the second magnetic sensing element MR2, and the magnetic detection elements H3 and H4 are mounted on the second substrate surface 35b facing the other axial side L2 of the first substrate 35. As described above, the first substrate 35 has the magnetic power generation element W mounted at the center of the first substrate surface 35a. Therefore, the two elements (magnetic power generation element W, second magnetic sensing element MR2) that should be placed at the substrate center are arranged separately on the front and back of the substrate. The magnetic detection elements H3 and H4 are arranged at positions shifted by 90° in mechanical angle in the phase of rotation about the rotation axis L.

[0036] Here, in the specific example of the magnetic encoder 1A shown in FIG. 5, FIG. 6, and FIG. 7, a board holder 37 is fixed to the first board 35 from the side of the magnet holder 3 to form a board unit 38. The first magnetic sensing element MR1 is disposed in a through-hole of the board holder 37, and is connected to a sensor circuit provided on the first board 35 via a flexible wiring board (not shown). The board unit 38 is fixed to an encoder holder 39 disposed so as to surround the magnet holder 3, thereby forming a predetermined gap between the first magnetic sensing element MR1 and the second magnet 12, and between the magnetic detection elements H1 to H7 and the first magnet 11. It is also possible to eliminate the board holder 37 and directly fix the first board 35 on which the first magnetic sensing element MR1, the second magnetic sensing element MR2, and the magnetic detection elements H1 to H7 are mounted to the encoder holder 39.

[0037] The first magneto-sensitive element MR1 and the second magneto-sensitive element MR2 are magnetoresistance effect elements. The first magneto-sensitive element MR1 and the second magneto-sensitive element MR2 have an A-phase magnetic resistance pattern and a B-phase magnetic resistance pattern that are shifted by 90° in electrical angle from each other in the phase of rotation about the rotation axis L. The A-phase magnetic resistance pattern has a +a-phase magnetic resistance pattern and a -a-phase magnetic resistance pattern that are shifted by 180 in electrical angle. The B-phase magnetic resistance pattern has a +b-phase magnetic resistance pattern and a -b-phase magnetic resistance pattern that are shifted by 180 in electrical angle.

[0038] The first magneto-sensitive element MR1 outputs two periods of a sine signal and a cosine signal each time the rotor 2 rotates through an angle corresponding to one pair of magnetic poles of the second magnet 12. The microcontroller unit 41A (position calculation unit) calculates an angular position by performing an arctangent calculation based on the output (sine signal and cosine signal) of the first magneto-sensitive element MR1. As a result, when the number of magnetic pole pairs of the second magnet 12 is P, P periods of calculated angle values ​​are obtained for one rotation of the rotor 2.

[0039] The second magneto-sensitive element MR2 faces the first magnet 11 having a pair of magnetic poles, and therefore outputs two periods of sine and cosine signals during one rotation of the rotating body 2. The microcontroller unit 41A (position calculation section) performs an arctangent calculation based on the sine and cosine signals to calculate an angle.

[0040] The magnetic detection elements H3 and H4 are Hall elements. The magnetic detection elements H3 and H4 output one period of rectangular wave signals that are out of phase with each other by 90° during one rotation of the rotating body 2. The microcontroller unit 41A (position calculation unit) performs a process of determining, for example, which section of the rectangular wave the magnetic detection elements H3 and H4 are in based on the output patterns of the magnetic detection elements H3 and H4.

[0041] The microcontroller unit 41A (position calculation unit) calculates an angle calculation value for one period of one rotation based on the angle calculated by arctangent calculation from the output of the second magneto-sensitive element MR2 and the current section calculated from the outputs of the magnetic detection elements H3 and H4. This angle calculation value is combined with the angle calculation value for one rotation P period calculated from the output of the first magneto-sensitive element MR1 to calculate a one-rotation angle with high resolution.

[0042] Furthermore, the microcontroller unit 41A (position calculation section) performs a process of calculating the number of rotations of the rotating body 2 from the accumulated value of the change in the angle of one rotation. For example, a process of adding or subtracting a counter value is performed based on the result of determining which section the output (rectangular wave) of the magnetic detection elements H3, H4 is in. A value indicating the number of rotations is obtained by dividing the counter value by the number of counts during one rotation of the rotating body 2.

[0043] (Second one-rotation sensor part) The second one-rotation sensor unit 40B includes magnetic detection elements H5, H6, and H7 that face the first magnet 11 from one side L1 in the axial direction, and a microcontroller unit 41B that is connected to the magnetic detection elements H5, H6, and H7. The magnetic detection elements H5, H6, and H7 are Hall elements. The magnetic detection elements H5, H6, and H7 are mounted on the second substrate surface 35b of the first substrate 35, similar to the other magnetic detection elements H1 to H4 (see FIG. 6).

[0044] The magnetic detection elements H5, H6, and H7 are disposed at positions shifted from each other by 120° mechanical angle in the phase of rotation about the rotation axis L. Therefore, the magnetic detection elements H5, H6, and H7 output one period of sinusoidal waveform signals shifted from each other by 120° phase during one rotation of the rotor 2 (i.e., during passing through one pair of magnetic pole pairs).

[0045] The microcontroller unit 41B functions as a position calculation unit that calculates one rotation angle using the outputs of the magnetic detection elements H5, H6, and H7. For example, the microcontroller unit 41B performs a process of estimating the angular position of the rotating body 2 using the outputs of the magnetic detection elements H5, H6, and H7. To estimate the angular position, a correspondence table between the angular position of the rotating body 2 and a calculated value calculated from the outputs of the magnetic detection elements H5, H6, and H7 is used. During the initial setting of the magnetic encoder 1A, a learning process is performed in advance to perform one rotation of the rotating body 2 and create a correspondence table from the outputs of the magnetic detection elements H5, H6, and H7 during that time, and the created correspondence table is stored.

[0046] The outputs of the magnetic detection elements H5, H6, and H7 (sine-wave signals with mutually out-of-phase shifts) can be converted into a predetermined number of codes corresponding to the angular position. For example, by combining the result of determining whether each signal is positive or negative and the result of determining the magnitude relationship between them, the signals can be converted into codes from 0 to 11. A correspondence table is created by associating angular positions with each code as the rotor 2 rotates once. When calculating the one-rotation angle, the microcontroller unit 41B (position calculation unit) performs a process of calculating the above codes from the outputs of the magnetic detection elements H5, H6, and H7, and reading out the angular position corresponding to the calculated value from the correspondence table. The read angle is output as an estimate of the one-rotation angle.

[0047] (Absolute angle position integration calculation section) In addition to the four sensor units described above, the magnetic encoder 1A includes a management and supervision unit 50 for managing the entire system including the four sensor units and monitoring for abnormalities. Output from each sensor unit is input to the management and supervision unit 50. The management and supervision unit 50 includes a microcontroller unit 51 and a second nonvolatile memory 52. ​​The second nonvolatile memory 52 stores various information such as setting values ​​and parameters required for processing at the start of the magnetic encoder 1A. The microcontroller unit 51 includes an absolute angle position integration calculation unit 53.

[0048] The absolute angle position integration calculation unit 53 calculates the absolute angle position of multiple rotations of the rotor 2 using two systems of multiple rotation information (first multiple rotation information and second multiple rotation information) and two systems of single rotation angles (first single rotation angle and second single rotation angle). For example, the above cross check determines whether the outputs of the two systems of multiple rotation sensor units are normal (i.e., whether the cumulative number of rotations matches), so if it is determined that one is not normal, the absolute angle position is calculated using the output value of the other system. Similarly, if the outputs of the two systems of single rotation sensor units are normal (i.e., whether the cumulative number of rotations matches) by the above cross check, the absolute angle position is calculated using the output value of the other system. is normal (i.e., the one rotation angle is the same), so if one is determined to be abnormal, the absolute angular position is calculated using the output value of the other.

[0049] Here, when the magnetic encoder 1A is started up, the absolute angle position integration calculation unit 53 calculates the absolute angle position of multiple rotations using the output (first multiple rotation information) of the first multiple rotation sensor unit 20A. That is, the absolute angle position of multiple rotations of the rotating body 2 is calculated by combining the first multiple rotation information read out from the first non-volatile memory 22A of the first multi-rotation sensor unit 20A at the time of start-up with the one-rotation angle calculated by the first one-rotation sensor unit 40A or the second one-rotation sensor unit 40B at the time of start-up.

[0050] Furthermore, after calculating the absolute angular position of multiple rotations of the rotor 2 using the first multiple rotation information read from the first non-volatile memory 22A at startup, the absolute angular position integration calculation unit 53 calculates the number of rotations from a count value based on the change in one rotation angle in the first one-rotation sensor unit 40A or the second one-rotation sensor unit 40B until the power is turned off, and combines this with the first multiple rotation information at startup to calculate multiple rotation information different from the first multiple rotation information that is continuously updated in the first multiple rotation sensor unit 20A. Then, the absolute angular position of multiple rotations of the rotor 2 is calculated by combining the multiple rotation information calculated based on the change in the one-rotation angle with the one-rotation angle.

[0051] (Effects of the First Embodiment) As described above, the magnetic encoder 1A of the first embodiment includes two sets of multi-rotation sensor units that detect the rotation of the rotor 2, two sets of one-rotation sensor units that detect a one-rotation angle that is an angular position within a range of one rotation of the rotor 2, a first magnet 11 having a pair of N poles and S poles magnetized, and an annular second magnet 12 having a second track T2 in which multiple pairs of N poles and S poles are magnetized alternately in the circumferential direction and arranged coaxially with the first magnet 11. The two sets of multi-rotation sensor units include a first multi-rotation sensor unit 20A having a magnetic power generation element W facing the first magnet 11 and calculating first multi-rotation information corresponding to the cumulative number of rotations of the rotor 2 based on a detection signal of a current generated by the magnetic power generation element W, and a second multi-rotation sensor unit 20B facing the first magnet 11 and calculating second multi-rotation information corresponding to the cumulative number of rotations of the rotor 2 based on outputs of first and second magnetic detection elements H1 and H2 that are separated by 90° in mechanical angle. The first multi-rotation sensor unit 20A and the second multi-rotation sensor unit 20B each perform a cross-check process to verify whether the first multi-rotation information and the second multi-rotation information are normal. The two sets of one-rotation sensors include a first one-rotation sensor unit 40A that calculates a first one-rotation angle based on the outputs of a first magnetic sensing element MR1 facing the first magnet 11, third and fourth magnetic sensing elements H3 and H4 facing the first magnet 11 and spaced apart by 90° in mechanical angle, and a second magnetic sensing element MR2 facing the second magnet 12, and a second one-rotation sensor unit 40B that calculates a second one-rotation angle based on the outputs of a first magnetic sensing element group consisting of three or more magnetic sensing elements including fifth, sixth, and seventh magnetic sensing elements H5, H6, and H7 facing the first magnet 11 and arranged in the circumferential direction. The first one-rotation sensor unit 40A and the second one-rotation sensor unit 40B perform a cross-check process to verify whether the first one-rotation angle and the second one-rotation angle are normal or not.

[0052] Furthermore, the magnetic encoder 1A of the first embodiment includes a management and supervision unit 50 connected to the first multi-rotation sensor unit 20A, the second multi-rotation sensor unit 20B, the first single-rotation sensor unit 40A, and the second single-rotation sensor unit 40B. The management and supervision unit 50 includes an absolute angle position integration calculation unit 53 that calculates an absolute angle position based on the first multi-rotation information, the second multi-rotation information, the first single-rotation angle, and the second single-rotation angle.

[0053] In this way, the magnetic encoder 1A of the first embodiment has two systems of multi-rotation sensor units that each calculate multi-rotation information and perform a cross-check process to verify whether the calculated multi-rotation information is normal. Similarly, two systems of one-rotation sensor units that detect the one-rotation angle are provided. , and similarly performs cross-check processing. In this way, a redundant system is constructed by providing two systems of detection elements and calculation units for outputting absolute angular position, so even if a failure occurs, the correct absolute angular position can be calculated from the output of the non-failed system. This makes it possible to avoid a situation in which an abnormal absolute angular position continues to be output because a failure cannot be detected.

[0054] In addition, in the first embodiment, the redundant system is entirely constructed using magnetic detection mechanisms, so that the configuration can be simplified, miniaturized, and reduced in cost compared to when optical detection mechanisms are used. In addition, there are advantages in that malfunctions caused by dirt are unlikely to occur and durability is high. Furthermore, since one system of the multi-rotation sensor unit is equipped with a magnetic power generation element W, multi-rotation information can be continuously updated even without a battery or external power supply.

[0055] That is, the first multi-rotation sensor unit 20A in the first embodiment includes a first non-volatile memory 22A in which the first multi-rotation information is updated by the current generated in the magnetic generating element W even when there is no external power supply. The absolute angle position integration calculation unit 53 calculates the absolute angle position based on the first multi-rotation information read from the first non-volatile memory 22A at startup. In this way, even if the rotating body 2 moves while power is not being supplied, the number of rotations will not become unknown, and an accurate absolute angle position can be output at startup.

[0056] In the first embodiment, the second magnetic sensing element MR2 is a magnetoresistance effect element having a magnetoresistance pattern of phase A and a magnetoresistance pattern of phase B having a phase difference of 90°, the second tracks T2 are arranged in two rows in the radial direction, the positions of the S pole and the N pole of the adjacent second tracks T2 are shifted by one pole in the circumferential direction, and the second magnetic sensing element MR2 faces the boundary between the adjacent second tracks T2. In this way, the magnetoresistance effect element is disposed in a rotating magnetic field whose direction changes in the in-plane direction of each track. Therefore, the detection accuracy can be improved.

[0057] (Modification of the first embodiment) (1) In the first embodiment, two sets of magnetic detection elements are provided, the magnetic detection elements H1 and H2 of the second multi-rotation sensor unit 20B and the magnetic detection elements H3 and H4 of the first one-rotation sensor unit 40A, which are separated by a mechanical angle of 90°. However, the first one-rotation sensor unit 40A may be configured to calculate the one-rotation angle using the outputs of the magnetic detection elements H1 and H2 instead of the outputs of the magnetic detection elements H3 and H4. In this way, the number of magnetic detection elements can be reduced.

[0058] That is, the magnetic encoder 1A of embodiment 1 can be configured to include a first one-rotation sensor unit 40A that calculates a first one-rotation angle based on the outputs of the first magnetic sensing element MR1 facing the first magnet 11, the first and second magnetic detection elements H1, H2 or the third and fourth magnetic detection elements H3, H4 facing the first magnet 11 and separated by 90° mechanical angle, and the second magnetic sensing element MR2 facing the second magnet 12, and a second one-rotation sensor unit that calculates a second one-rotation angle based on the outputs of a first magnetic detection element group consisting of three or more magnetic detection elements including the fifth, sixth and seventh magnetic detection elements H5, H6 and H7 facing the first magnet 11 and aligned in the circumferential direction.

[0059] (2) The second one-rotation sensor unit 40B in the first embodiment includes three magnetic detection elements H5, H6, and H7 facing the first magnet 11, but in order to perform processing to estimate the one-rotation angle, the number of magnetic detection elements facing the first magnet 11 and aligned in the circumferential direction may be three or more, and the arrangement is not limited to an interval of 120 mechanical degrees. In other words, the second one-rotation sensor unit 40B may include at least three magnetic detection elements facing the first magnet 11 and aligned at equal angular intervals in the circumferential direction.

[0060] (3) In each sensor unit of the first embodiment, a microcomputer is used as an electronic element for performing calculations. Although a controller unit is used, other electronic elements may also be used.

[0061] (4) The management and supervision unit 50 provided in the magnetic encoder 1A of the first embodiment can be integrated into either one of two single-rotation sensor units or two multi-rotation sensor units. FIG. 2 is a configuration diagram and functional block diagram of a fourth modified example of the first embodiment. As shown in FIG. 2, the magnetic encoder 1B of the fourth modified example of the first embodiment has the functions of the management and supervision unit 50 integrated into a first single-rotation sensor unit 40C. Hereinafter, the same components as those of the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

[0062] As shown in Fig. 2, the magnetic encoder 1B of the fourth modification includes a first multi-rotation sensor unit 20A, a second multi-rotation sensor unit 20B, a first one-rotation sensor unit 40C, and a second one-rotation sensor unit 40B. The first one-rotation sensor unit 40C includes a microcontroller unit 41C and a second non-volatile memory 42 connected to the first magnetic sensing element MR1, the second magnetic sensing element MR2, and the magnetic detection elements H1 and H2. The second multi-rotation sensor unit 20B may include other configurations than those described above. The second non-volatile memory 42 stores various information such as setting values ​​and parameters required for processing at the start of the magnetic encoder 1B.

[0063] The microcontroller unit 41C functions as a position calculation unit that calculates a one-rotation angle using the outputs of the first magneto-sensitive element MR1, the second magneto-sensitive element MR2, and the magnetic detection elements H1 and H2, and also includes an absolute angle position integration calculation unit 43. The first multi-rotation information, the second multi-rotation information, the first one-rotation angle, and the second one-rotation angle are input to the absolute angle position integration calculation unit 43, and processing is performed to calculate an absolute angle position of multiple rotations from these input values ​​in the same manner as in the first embodiment.

[0064] (Effects of Modification 4) As in the first embodiment, the magnetic encoder 1B of the fourth modification includes two systems of multi-rotation sensor units and two systems of single-rotation sensor units, and verifies whether the output is normal by cross-checking. Therefore, the same effects as those of the first embodiment can be obtained. That is, since a redundant system is constructed by providing two systems of detection elements and calculation units for outputting the absolute angular position, even if a failure occurs, the correct absolute angular position can be calculated from the output of the non-failed system. Therefore, it is possible to avoid a situation in which a failure cannot be detected and an abnormal absolute angular position continues to be output.

[0065] In addition, since the same magnetic detection mechanism as in embodiment 1 is used, the configuration can be simplified, miniaturized, and cost reduced, and durability is high, compared to when an optical detection mechanism is used. Furthermore, one of the two multi-rotation sensor units can continue to update the multi-rotation information even without a battery or external power supply.

[0066] Furthermore, in the magnetic encoder 1B of the fourth modification, the first one-rotation sensor unit 40C includes an absolute angle position integration calculation unit 43 that calculates an absolute angle position based on the first multiple-rotation information, the second multiple-rotation information, the first one-rotation angle, and the second one-rotation angle. Therefore, since there is no need to provide a management and supervision unit 50 and the second one-rotation sensor unit 40C also serves as a unit having the functions of the absolute angle position integration calculation unit 43, the configuration can be simplified and costs can be reduced.

[0067] Note that a configuration may be adopted in which any one of the first multi-rotation sensor unit 20A, the second multi-rotation sensor unit 20B, and the first single-rotation sensor unit 40B has the function of the absolute angle position integration calculation unit 43.

[0068] (Embodiment 2) FIG. 3 is a configuration diagram and a functional block diagram of a main part of a magnetic encoder 1C according to a second embodiment. As shown in Fig. 3, in the magnetic encoder 1C of the second embodiment, the configuration of the two-system multi-rotation sensor unit is the same as that of the first embodiment. However, the configuration of the magnetic detection element in the multi-rotation sensor unit and the method of calculating the angle of one rotation are different from those of the first embodiment. Hereinafter, the same components as those of the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted.

[0069] The magnetic encoder 1C includes a second magnet 12 and a first magnet 11 having the same configuration as in embodiment 1. The magnetic encoder 1C also includes a first multi-rotation sensor unit 20A and a second multi-rotation sensor unit 20B having the same configuration as in embodiment 1 as two-system multi-rotation sensor units. The magnetic encoder 1C also includes a first one-rotation sensor unit 40D and a second one-rotation sensor unit 40E as two-system one-rotation sensor units.

[0070] In the magnetic encoder 1C, similarly to the first embodiment, the supervisory unit 50 is not integrated into the first one-rotation sensor unit 40D, and the absolute angle position integration calculation unit 53 is provided in the supervisory unit 50. Note that, similarly to the fourth modification of the first embodiment, the supervisory unit 50 and the first one-rotation sensor unit 40D can also be integrated together.

[0071] The first one-rotation sensor unit 40D includes a first magnetic sensing element MR1 facing the second magnet 12, three magnetic detection elements H3, H4, and H5 facing the third magnet 13, and a microcontroller unit 41D. The microcontroller unit 41D has a function of a position calculation unit that calculates the one-rotation angle.

[0072] In the first one-rotation sensor unit 40D, similarly to the first embodiment, an arctangent calculation is performed based on the output (sine signal and cosine signal) of the first magneto-sensitive element MR1 facing the multi-pole second magnet 12. As a result, when the number of magnetic pole pairs of the second magnet 12 is P, an angle calculation value of P periods is obtained for one rotation of the rotor 2. Therefore, an angle calculation value with high resolution is obtained.

[0073] On the other hand, in the first one-rotation sensor unit 40D, unlike the first embodiment, a low-resolution angle calculation value is calculated from the outputs of the magnetic detection elements H3, H4, and H5. The magnetic detection elements H3, H4, and H5 are Hall elements. The magnetic detection elements H3, H4, and H5 face the first magnet 11 having one magnetic pole pair, and are arranged at positions shifted from each other by 120° in mechanical angle in the phase of rotation about the rotation axis L. The magnetic detection elements H3, H4, and H5 output one-cycle sinusoidal waveform signals shifted from each other by 120° while the rotor 2 rotates once (i.e., while passing through one pair of magnetic pole pairs).

[0074] The microcontroller unit 41D (position calculation section) performs a process of estimating the angular position of the rotating body 2 using the outputs of the magnetic detection elements H3, H4, and H5. The content of the estimation process is the same as the estimation process performed by the second one-rotation sensor section 40 in the first embodiment using the outputs of the magnetic detection elements H1, H2, and H3, so a description thereof will be omitted. As a result, a low-resolution angle estimation value is obtained. The microcontroller unit 41D (position calculation section) calculates a one-rotation angle by combining a high-resolution angle calculation value obtained from the output of the first magneto-sensitive element MR1 and a low-resolution angle estimation value obtained from the outputs of the magnetic detection elements H3, H4, and H5.

[0075] Next, the second one-rotation sensor unit 40E includes a second magneto-sensitive element MR2 facing the second magnet 12, two magnetic detection elements H1 and H2 facing the first magnet 11, and a microcontroller unit 41E. The microcontroller unit 41E has a function of a position calculation unit that calculates a one-rotation angle. The second one-rotation sensor unit 40E uses the output of the magnetic detection elements H1 and H2 constituting the second multi-rotation sensor unit 20B to calculate the one-rotation angle. That is, the magnetic detection elements H1 and H2 are used as two sensor units, the second multi-rotation sensor unit 20B and the second one-rotation sensor unit 40E.

[0076] In the second one-rotation sensor section 40E, the second magneto-sensitive element MR2 faces the first magnet 11 having a pair of magnetic pole pairs, and therefore outputs two periods of sine and cosine signals during one rotation of the rotating body 2. The microcontroller unit 41E (position calculation section) performs an arctangent calculation based on the sine and cosine signals to calculate an angle.

[0077] The magnetic detection elements H1 and H2 output one cycle of rectangular wave signals that are out of phase with each other by 90° during one rotation of the rotating body 2. The microcontroller unit 41E (position calculation unit) performs a process of determining, for example, which section of the rectangular wave the magnetic detection elements H1 and H2 are in based on the output patterns of the magnetic detection elements H1 and H2.

[0078] The microcontroller unit 41E (position calculation section) calculates an angle calculation value for one period of one rotation based on the angle calculated by arctangent calculation from the output of the second magneto-sensitive element MR2 and the current section calculated from the outputs of the magnetic detection elements H1, H1.

[0079] The absolute angle position integration calculation unit 53 uses the outputs of the first multi-rotation sensor unit 20A and the second multi-rotation sensor unit 20B, and the first one-rotation sensor unit 40D and the second one-rotation sensor unit 40E to calculate the absolute angle position of multiple rotations of the rotor 2. At that time, similarly to each of the above embodiments, the absolute angle position is calculated using the multi-rotation information and one-rotation angle that are determined to be normal using the cross-check results.

[0080] (Effects of the second embodiment) As described above, the magnetic encoder 1C of the second embodiment includes two sets of multi-rotation sensor units that detect the rotation of the rotor 2, two sets of one-rotation sensor units that detect a one-rotation angle that is an angular position within a range of one rotation of the rotor 2, a first magnet 11 having a pair of N poles and S poles magnetized, and a ring-shaped second magnet 12 having a second track T2 having multiple pairs of N poles and S poles magnetized alternately in the circumferential direction and arranged coaxially with the first magnet 11. The two sets of multi-rotation sensor units include a first multi-rotation sensor unit 20A having a magnetic power generation element W facing the first magnet and calculating first multi-rotation information corresponding to the cumulative number of rotations of the rotor 2 based on a detection signal of a current generated by the magnetic power generation element W, and a second multi-rotation sensor unit 20B facing the first magnet 11 and calculating second multi-rotation information corresponding to the cumulative number of rotations of the rotor 2 based on the output of first and second magnetic detection elements H1 and H2 that are separated by 90° in mechanical angle. The first multi-rotation sensor unit 20A and the second multi-rotation sensor unit 20B each perform a cross-check process to verify whether the first multi-rotation information and the second multi-rotation information are normal. The two sets of one-rotation sensors include a first one-rotation sensor unit 40C that calculates a first one-rotation angle based on the output of a first magnetic detection element group consisting of three or more magnetic detection elements including a first magnetic sensing element MR1 facing the second magnet 12 and a third, fourth, and fifth magnetic detection elements H3, H4, and H5 facing the first magnet 11 and arranged in the circumferential direction, and a second one-rotation sensor unit 40B that calculates a second one-rotation angle based on a second magnetic sensing element MR2 facing the first magnet 11 and the first and second magnetic detection elements H1 and H2. The first one-rotation sensor unit 40C and the second one-rotation sensor unit 40B each perform a cross-check process to verify whether the first one-rotation angle and the second one-rotation angle are normal.

[0081] Also, like the first embodiment, the magnetic encoder 1C of the second embodiment includes two systems of multi-rotation sensor units and two systems of single-rotation sensor units, and verifies whether the output is normal by cross-checking. Therefore, the same effects as those of the first embodiment can be obtained. That is, since a redundant system is constructed by providing two systems of detection elements and calculation units for outputting the absolute angular position, even if a failure occurs, the correct absolute angular position can be calculated from the output of the non-failed system. Therefore, it is possible to avoid a situation in which a failure cannot be detected and an abnormal absolute angular position continues to be output.

[0082] In addition, since all magnetic detection mechanisms are used as in the first embodiment, the optical detection devices are not required. Compared to the case where a multi-rotation sensor is used, the structure can be simplified, miniaturized, and cost reduced, and durability is high. Furthermore, one of the two multi-rotation sensor units can continue to update the multi-rotation information even without a battery or external power supply.

[0083] (Modification of the second embodiment) (1) In the second embodiment, the two magnetic detection elements H1 and H2, which are separated by 90° in mechanical angle, are shared by the second multi-rotation sensor unit 20B and the second one-rotation sensor unit 40E, but it is also possible to adopt a configuration in which the two magnetic detection elements are not shared, but each of them has its own magnetic detection element. In this case, the second one-rotation sensor unit 40E has its own magnetic detection elements H6 and H7.

[0084] That is, the magnetic encoder 1C of embodiment 2 can be provided with a second magnetic sensing element MR2 facing the first magnet 11, and a second one-rotation sensor unit 40B that calculates a second one-rotation angle based on the outputs of the first and second magnetic detection elements H1, H2 or sixth and seventh magnetic detection elements H6, H7 different from the first and second magnetic detection elements H1, H2 and separated by 90° mechanical angle.

[0085] (2) The first one-rotation sensor unit 40D of the second embodiment includes three magnetic detection elements H3, H4, and H5 facing the first magnet 11, but in order to perform the process of estimating the one-rotation angle, the number of magnetic detection elements facing the first magnet 11 and aligned in the circumferential direction may be three or more, and the arrangement is not limited to an interval of 120 mechanical degrees. In other words, the second one-rotation sensor unit 40D may include at least three magnetic detection elements facing the first magnet 11 and aligned at equal angular intervals in the circumferential direction.

[0086] (Embodiment 3) Fig. 4 is a configuration diagram and a functional block diagram of the main parts of a magnetic encoder 1D of embodiment 3. As shown in Fig. 4, the magnetic encoder 1D of embodiment 3 differs from embodiments 1 and 2 in that both of the multi-rotation sensor units of the two systems are configured to be able to update multi-rotation information without a power supply. Also, to accommodate a hollow shaft, the arrangement of the elements arranged on the rotation axis and the configuration of the magnets have been changed, and a part of the calculation method of the one-rotation angle has been changed in accordance with the change in the arrangement of the elements. Hereinafter, the same components as those of embodiments 1 and 2 are denoted by the same reference numerals, and description thereof will be omitted.

[0087] The magnetic encoder 1D includes a first magnet 11D, a second magnet 12, and a third magnet 13, all of which are annular, as magnets that generate a magnetic field for detection. The first magnet 11D is disposed on the outer periphery of the other surface 34 (see FIG. 5) of the magnet holder 32. The first magnet 11D has an annular first track T1 in which one N pole and one S pole are magnetized in the circumferential direction, and the center of the track T1 coincides with the rotation axis L. The first tracks T1 are arranged in two rows in the radial direction. The positions of the N pole and the S pole of the first tracks T1 adjacent in the radial direction are shifted by one pole in the circumferential direction. The configuration of the second magnet 12 is the same as that of the first and second embodiments. The third magnet 13 is disposed on the inner periphery of one surface 33 (see FIG. 5) of the magnet holder 32. The third magnet 13 is magnetized with one N pole and one S pole, and the center of the track T1 coincides with the rotation axis L.

[0088] As shown in FIG. 4, a magnetic encoder 1D includes a first multi-rotation sensor unit 20C, a second multi-rotation sensor unit 20D, a first single-rotation sensor unit 40F, and a second single-rotation sensor unit 40G.

[0089] The first multi-rotation sensor unit 20C includes a first magnetic generating element W1, a microcontroller unit 21C, and a first non-volatile memory 22C. The microcontroller unit 21C includes a multi-rotation information generating unit 23C. The second multi-rotation sensor unit 20D includes a second magnetic generating element W2, a microcontroller unit 21D, and a first non-volatile memory 22D. The microcontroller unit 21D includes a multi-rotation information generating unit 23D. The first magnetic The magnetic generating element W1 and the second magnetic generating element W2 are not disposed on the rotation axis L and face the annular first magnet 11D. The first magnetic generating element W1 and the second magnetic generating element W2 face the first magnet 11D at positions separated by 180° in mechanical angle. The first magnetic generating element W1 and the second magnetic generating element W2 are mounted on a second substrate 36 facing the other surface 34 of the magnet holding unit 32.

[0090] The first one-rotation sensor unit 40F includes a first magnetic sensing element MR1 facing the second magnet 12, three magnetic detection elements H1, H2, H3 facing the third magnet 13, a microcontroller unit 41F, and a third nonvolatile memory 45. The microcontroller unit 41F includes an absolute angle position integration calculation unit 43 to which two systems of multi-rotation information and two systems of one-rotation angles are input. Instead of providing the absolute angle position integration calculation unit 43 in the first one-rotation sensor unit 40F, a management and supervision unit independent of the first one-rotation sensor unit 40F can also be provided, as in the first embodiment.

[0091] In the first one-rotation sensor unit 40F, the magnetic detection elements H1, H2, and H3 are disposed at positions shifted from each other by 120° in mechanical angle in the phase of rotation about the rotation axis L. The first one-rotation sensor unit 40F calculates a one-rotation angle with high resolution by the same calculation process as the first one-rotation sensor unit 40D of the second embodiment, based on the output of the first magneto-sensitive element MR1 and the outputs of the magnetic detection elements H1, H2, and H3.

[0092] The second one-rotation sensor unit 40G includes three magnetic detection elements H4, H5, and H6 facing the third magnet 13, and a microcontroller unit 41G. The magnetic detection elements H4, H5, and H6 are disposed at positions shifted from each other by 120° in mechanical angle in the phase of rotation about the rotation axis L. The second one-rotation sensor unit 40G calculates a one-rotation angle with low resolution by the same calculation process as the first one-rotation sensor unit 40B of the first embodiment.

[0093] In the first one-rotation sensor unit 40F, the absolute angle position integration calculation unit 43 uses the outputs of the first multi-rotation sensor unit 20C and the second multi-rotation sensor unit 20D, and the first one-rotation sensor unit 40F and the second one-rotation sensor unit 40G to calculate the absolute angle position of multiple rotations of the rotor 2. At that time, similarly to each of the above embodiments, the absolute angle position is calculated using the multi-rotation information and one-rotation angle that are determined to be normal using the cross-check result.

[0094] (Effects of the Third Embodiment) As described above, the magnetic encoder 1D of embodiment 3 has two sets of multi-rotation sensor units that detect the rotation of the rotating body 2, two sets of one-rotation sensor units that detect the one-rotation angle, which is the angular position within the range of one rotation of the rotating body 2, annular first magnet 11 having a first track T1 on which a pair of N poles and S poles are magnetized, annular second magnet 12 having a second track T2 on which multiple pairs of N poles and S poles are magnetized alternately in the circumferential direction and arranged coaxially with the first magnet 11, and annular third magnet 13 on which a pair of N poles and S poles are magnetized and arranged coaxially with the first magnet 11 and the second magnet 12. The two multi-rotation sensor units include a first multi-rotation sensor unit 20C that has a first magnetic generating element W1 facing the first magnet 11 and calculates first multi-rotation information corresponding to the accumulated number of rotations of the rotor 2 based on a detection signal of a current generated in the first magnetic generating element W1, and a second multi-rotation sensor unit 20D that has a second magnetic generating element W2 facing the first magnet 11 and calculates second multi-rotation information corresponding to the accumulated number of rotations of the rotor 2 based on a detection signal of a current generated in the second magnetic generating element W2. Each of the first multi-rotation sensor unit 20C and the second multi-rotation sensor unit 20D performs a cross-check process to verify whether the first multi-rotation information and the second multi-rotation information are normal. The two sets of one-rotation sensor units include a first one-rotation sensor unit 40F that calculates a first one-rotation angle based on the output of a first magnetic detection element group consisting of three or more magnetic detection elements including a second magnetic sensing element MR2 facing the second magnet 12 and first, second, and third magnetic detection elements H1, H2, and H3 facing the third magnet 13 and aligned in the circumferential direction, and a fourth, fifth, and sixth magnetic detection elements H4, H5, and H6 facing the third magnet 13 and aligned in the circumferential direction. and a second one-rotation sensor unit 40B that calculates a second one-rotation angle based on the output of a second magnetic detection element group consisting of three or more magnetic detection elements including the first one-rotation sensor unit 40F and the second one-rotation sensor unit 40B perform a cross-check process to verify whether the first one-rotation angle and the second one-rotation angle are normal or not.

[0095] The magnetic encoder 1D of the third embodiment, like the first and second embodiments, includes two systems of multi-rotation sensor units and two systems of single-rotation sensor units, and verifies whether the output is normal by cross-checking. Therefore, the same effects as those of the first and second embodiments can be obtained. That is, since a redundant system is constructed by providing two systems of detection elements and calculation units for outputting the absolute angular position, even if a failure occurs, the correct absolute angular position can be calculated from the output of the non-failed system. Therefore, it is possible to avoid a situation in which an abnormal absolute angular position continues to be output because a failure cannot be detected.

[0096] In addition, since all magnetic detection mechanisms are used as in the first and second embodiments, the configuration can be simplified, miniaturized, and cost reduced, and durability is high, compared to when optical detection mechanisms are used. Furthermore, both of the two multi-rotation sensor units can continue to update multi-rotation information even without a battery or external power supply. Therefore, the correct absolute angle position can be output without the burden of replacing the battery.

[0097] Furthermore, similarly to the fourth modification of the first embodiment, the management and supervision unit 50 is not provided, and the second one-rotation sensor unit 40F is used as a unit also having the function of the absolute angle position integration calculation unit 43. This allows the configuration to be simplified, and costs to be reduced. Note that the function of the absolute angle position integration calculation unit 53 can also be provided to any one of the first multi-rotation sensor unit 20C, the second multi-rotation sensor unit 20D, and the first one-rotation sensor unit 40G.

[0098] In the third embodiment, the magnet holder 3 includes an annular magnet holding portion 32 centered on the rotation axis of the rotor 2. The second magnet 12 is disposed on the outer periphery of one surface 33 of the magnet holding portion 32, and the third magnet 13 is disposed on the inner periphery of the one surface 33. The first magnet 11 is disposed on the other surface of the magnet holding portion 32. The second magnetic sensing element MR2, the first, second and third magnetic detection elements H1, H2 and H3, and the fourth, fifth and sixth magnetic detection elements H4, H5 and H6 are disposed on a first substrate 35 facing the one surface 33. The first magnetic power generation element W1 and the second magnetic power generation element W2 are disposed on a second substrate 36 facing the other surface. In this way, the magnets are disposed on the front and back of the magnet holding portion 32, and the magnetic power generation elements W and W2 and the first magnetic sensing element MR1 face the magnet holding portion 32 from the opposite side, thereby making it possible to make the detection mechanism simple and compact in configuration. In addition, since the detection element is not disposed on the rotation axis L, it is possible to accommodate a hollow shaft.

[0099] (Modification of the third embodiment) The first one-rotation sensor unit 40F of the third embodiment includes three magnetic detection elements H1, H2, and H3 (first detection element group) facing the third magnet 13, and the second one-rotation sensor unit 40G includes three magnetic detection elements H4, H5, and H6 (second detection element group) facing the third magnet 13, but in order to perform the process of estimating the one-rotation angle, the number of magnetic detection elements facing the third magnet 13 and arranged in the circumferential direction may be three or more, and the arrangement is not limited to an interval of 120° mechanical angle. In other words, the first one-rotation sensor unit 40F and the second one-rotation sensor unit 40G each may include at least three magnetic detection elements facing the third magnet 13 and arranged at equal angular intervals in the circumferential direction.

[0100] (Other embodiments) In the third embodiment, the third magnet 13 is provided as a magnet that faces the magnetic detection elements H1 to H6, but a configuration in which the magnetic detection elements H1 to H6 face the first magnet 11 may be adopted. In this case, the third magnet 13 is not necessary.

[0101] The configurations of the above embodiments and modified examples can be combined as appropriate. [Explanation of symbols]

[0102] Reference Signs List 1A, 1B, 1C, 1D...magnetic encoder, 2...rotating body, 3...magnet holder, 11, 11D...first magnet, 12...second magnet, 13...third magnet, 20A, 20C...first multi-rotation sensor unit, 20B, 20D...second multi-rotation sensor unit, 21A, 21B...microcontroller unit, 22A, 22B...first non-volatile memory, 23A, 23B...multi-rotation information generating unit, 31...shaft portion, 32...magnet holding portion, 33...one side, 34...other side, 35...first board, 35a...first board surface, 35b...second board surface, 36...first board, 37...board holder, 38...board unit, 39...encoder holder, 40A, 40C, 40D, 40F...second 1-1 rotation sensor unit, 40B, 40E, 40G...second rotation sensor unit, 41A, 41B, 41C, 41D, 41E, 41F, 41G...microcontroller unit, 42, 45, 52...second non-volatile memory, 43, 53...absolute angle position integration calculation unit, 50...management and supervision unit, 51...microcontroller unit, T1...first track, T2...second track, L...rotation axis, L1...one side in the axial direction, L2...other side in the axial direction, MR1...first magnetic sensing element, MR2...second magnetic sensing element, H1, H2, H3, H4, H5, H6, H7...magnetic detection elements, W...magnetic generating element, W1...first magnetic generating element, W2...second magnetic generating element

Claims

1. A magnetic encoder for detecting an absolute angular position of a rotating body, Two sets of multi-rotation sensor units for detecting rotation of the rotating body; two sets of one-rotation sensor units for detecting a one-rotation angle which is an angular position within a range of one rotation of the rotating body; a first magnet having a pair of N and S poles magnetized; a second magnet having a ring-shaped second track in which a plurality of pairs of N poles and S poles are alternately magnetized in a circumferential direction and arranged coaxially with the first magnet; The two sets of multi-rotation sensor units include a first multi-rotation sensor unit including a magnetic generating element facing the first magnet, the first multi-rotation sensor unit calculating first multi-rotation information corresponding to a cumulative number of rotations of the rotor based on a detection signal of a current generated by the magnetic generating element; a second multi-rotation sensor unit that calculates second multi-rotation information corresponding to a cumulative number of rotations of the rotating body based on outputs of first and second magnetic detection elements that face the first magnet and are separated by a mechanical angle of 90°, performing a cross-check process for verifying whether the first multi-rotation sensor unit and the second multi-rotation sensor unit have the first multi-rotation information and the second multi-rotation information, respectively, normal; The two sets of one-rotation sensor units include a first one-rotation sensor unit that calculates a first one-rotation angle based on outputs of a first magnetic sensing element facing the second magnet, the first and second magnetic detection elements or third and fourth magnetic detection elements facing the first magnet and spaced apart by 90° in mechanical angle, and a second magnetic sensing element facing the first magnet; a second one-rotation sensor unit that calculates a second one-rotation angle based on outputs from a first magnetic detection element group consisting of three or more magnetic detection elements including fifth, sixth and seventh magnetic detection elements that face the first magnet and are aligned in a circumferential direction, A magnetic encoder characterized in that a cross-check process is performed in which the first one-rotation sensor unit and the second one-rotation sensor unit each verify whether the first one-rotation angle and the second one-rotation angle are normal.

2. A magnetic encoder for detecting an absolute angular position of a rotating body, Two sets of multi-rotation sensor units for detecting rotation of the rotating body; two sets of one-rotation sensor units for detecting a one-rotation angle which is an angular position within a range of one rotation of the rotating body; a first magnet having a pair of N and S poles magnetized; a second magnet having an annular shape and arranged coaxially with the first magnet, the second magnet including a second track having a plurality of pairs of N poles and S poles alternately magnetized in a circumferential direction; The two sets of multi-rotation sensor units include a first multi-rotation sensor unit including a magnetic generating element facing the first magnet, the first multi-rotation sensor unit calculating first multi-rotation information corresponding to a cumulative number of rotations of the rotor based on a detection signal of a current generated by the magnetic generating element; a second multi-rotation sensor unit that calculates second multi-rotation information corresponding to a cumulative number of rotations of the rotating body based on outputs of first and second magnetic detection elements that face the first magnet and are separated by a mechanical angle of 90°, performing a cross-check process for verifying whether the first multi-rotation sensor unit and the second multi-rotation sensor unit have the first multi-rotation information and the second multi-rotation information, respectively, normal; The two sets of one-rotation sensor units include a first one-rotation sensor unit that calculates a first one-rotation angle based on an output of a first magnetic detection element group consisting of three or more magnetic detection elements including a first magnetic sensing element facing the second magnet, and third, fourth and fifth magnetic detection elements facing the first magnet and aligned in the circumferential direction; a second one-rotation sensor unit that calculates a second one-rotation angle based on outputs of a second magnetic sensing element facing the first magnet, and the first and second magnetic detection elements or sixth and seventh magnetic detection elements different from the first and second magnetic detection elements and spaced apart by 90° in mechanical angle, A magnetic encoder characterized in that a cross-check process is performed in which the first one-rotation sensor unit and the second one-rotation sensor unit each verify whether the first one-rotation angle and the second one-rotation angle are normal.

3. A magnetic encoder for detecting an absolute angular position of a rotating body, Two sets of multi-rotation sensor units for detecting rotation of the rotating body; two sets of one-rotation sensor units for detecting a one-rotation angle which is an angular position within a range of one rotation of the rotating body; a first magnet having an annular shape and a first track having a pair of north and south poles magnetized thereon; a second magnet having a ring-shaped second track in which a plurality of pairs of N poles and S poles are alternately magnetized in a circumferential direction and arranged coaxially with the first magnet; a third magnet having a ring shape and a pair of N and S poles magnetized and arranged coaxially with the first magnet and the second magnet; The two sets of multi-rotation sensor units include a first multi-rotation sensor unit including a first magnetic generating element facing the first magnet, the first multi-rotation sensor unit calculating first multi-rotation information corresponding to a cumulative number of rotations of the rotor based on a detection signal of a current generated by the first magnetic generating element; a second multi-rotation sensor unit including a second magnetic generating element facing the first magnet and configured to calculate second multi-rotation information corresponding to a cumulative number of rotations of the rotor based on a detection signal of a current generated by the second magnetic generating element, performing a cross-check process for verifying whether the first multi-rotation sensor unit and the second multi-rotation sensor unit have the first multi-rotation information and the second multi-rotation information, respectively, normal; The two sets of one-rotation sensor units include a first one-rotation sensor unit that calculates a first one-rotation angle based on an output of a first magnetic detection element group consisting of three or more magnetic detection elements including a first magnetic sensing element facing the second magnet and first, second and third magnetic detection elements facing the third magnet and aligned in the circumferential direction; a second one-rotation sensor unit that calculates a second one-rotation angle based on outputs from a second magnetic detection element group consisting of three or more magnetic detection elements including fourth, fifth and sixth magnetic detection elements that face the third magnet and are aligned in a circumferential direction, A magnetic encoder characterized in that a cross-check process is performed in which the first one-rotation sensor unit and the second one-rotation sensor unit each verify whether the first one-rotation angle and the second one-rotation angle are normal.

4. a magnet holder including an annular magnet holding portion centered on a rotation axis of the rotor; The second magnet is disposed on an outer periphery of one surface of the magnet holder, The third magnet is disposed on an inner periphery of the one surface, The first magnet is disposed on the other surface of the magnet holder, the first magnetic sensing element, the first, second, and third magnetic detection elements, and the fourth, fifth, and sixth magnetic detection elements are disposed on a first substrate facing the one surface, 4. The magnetic encoder according to claim 3, wherein the first magnetic generating element and the second magnetic generating element are disposed on a second substrate facing the other surface.

5. a supervisory unit connected to the first multi-rotation sensor unit, the second multi-rotation sensor unit, the first single-rotation sensor unit, and the second single-rotation sensor unit; The said management and supervision department: The first multiple rotation information, the second multiple rotation information, the first single rotation angle, and the 4. The magnetic encoder according to claim 1, further comprising an absolute angular position integration calculation unit that calculates the absolute angular position based on a rotation angle of the magnetic pole.

6. One of the first one-rotation sensor unit and the second one-rotation sensor unit is 4. The magnetic encoder according to claim 1, further comprising an absolute angle position integration calculation unit that calculates the absolute angle position based on the first multi-rotation information, the second multi-rotation information, the first single rotation angle, and the second single rotation angle.

7. a non-volatile memory that stores the first multi-rotation information and updates the first multi-rotation information by a current generated by the magnetic generating element; 7. The magnetic encoder according to claim 6, wherein the absolute angular position integration calculation unit calculates the absolute angular position based on the first multi-rotation information read from the nonvolatile memory at startup.

8. the first magnetic sensing element is a magnetoresistance effect element including an A-phase magnetoresistance pattern and a B-phase magnetoresistance pattern having a phase difference of 90° from each other, The magnetic encoder according to any one of claims 1 to 3, characterized in that the second tracks are arranged in two rows in the radial direction, the positions of the S pole and N pole of adjacent second tracks are shifted by one pole in the circumferential direction, and the first magnetic sensing element faces the boundary between adjacent second tracks.

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