JP2019082358A - Angle detection device, relative angle detection device, torque sensor, electric power steering device and vehicle - Google Patents

Abstract

To provide an angle detection device and a relative angle detection device each of which can detect an angle with a higher degree of accuracy, and a torque sensor, an electric power steering device and a vehicle.SOLUTION: The angle detection device comprises: a first shaft; a first multipolar magnet; a first magnet sensor; a second magnet sensor; and an angle correction unit. The first magnet sensor can output a first distance correlation value in accordance with a first distance to the first multipolar magnet, and the second magnet sensor can output a second distance correlation value in accordance with a second distance to the first multipolar magnet. The angle correction unit calculates a first correction angle of the first multipolar magnet on the basis of a first angle detected by the first magnet sensor in accordance with rotation of the first multipolar magnet, the first distance correlation value, a second angle detected by the second magnet sensor in accordance with the rotation of the first multipolar magnet, and the second distance correlation value.SELECTED DRAWING: Figure 9

Description

  The present invention relates to an angle detection device, a relative angle detection device, a torque sensor, an electric power steering device, and a vehicle.

  The vehicle is equipped with an electric power steering device that assists steering by the assist steering force generated by the motor. The electric power steering apparatus controls the motor based on the steering torque output by the torque sensor. The torque sensor calculates a steering torque from the rotation angle of the input shaft and the output shaft detected by the angle detection device. For example, Patent Document 1 describes an example of an angle detection device. The angle detection device described in Patent Document 1 detects a position of a target provided on a rotating body, and outputs a detection signal corresponding to the position, and a detection signal obtained by multiplying a gain. An angle calculation unit that calculates a rotation angle, and a gain correction unit that corrects a gain so that the difference between the maximum value and the minimum value of the detection signal becomes a preset reference difference.

JP 2003-83823 A

  Here, it is desired that the angle detection device detect the angle more accurately.

  The present invention has been made in view of the above problems, and provides an angle detection device, a relative angle detection device, a torque sensor, an electric power steering device, and a vehicle that can detect an angle more accurately. The purpose is.

  In order to achieve the above object, the angle detection device according to one aspect rotates in conjunction with the rotation of the first shaft and the first shaft, and different magnetic poles alternate along the circumferential direction of the first shaft. A first multipole magnet disposed, a first magnetic sensor disposed on the outer circumferential side of the first multipole magnet, a second magnetic sensor disposed on the outer circumferential side of the first multipole magnet, and an angle correction unit And the first magnetic sensor and the second magnetic sensor are different from the 180 ° symmetrical position sandwiching the first multipole magnet, and are different in the circumferential direction around the first multipole magnet. The first magnetic sensor may be disposed at a position, and the first magnetic sensor may output a first distance correlation value according to a first distance to the first multipole magnet, and the second magnetic sensor may be configured to output the first multipole magnet. A second distance correlation value corresponding to a second distance between The second magnetic sensor detects the first angle detected by the first magnetic sensor according to the rotation of the first multipole magnet, the first distance correlation value, and the rotation of the first multipole magnet. A first correction angle of the first multipole magnet is calculated based on the second angle and the second distance correlation value.

  According to this, the angle detection device detects the rotation angle of the first multipole magnet in which the error due to the first displacement relative to the reference rotation axis of the first shaft or the first multipole magnet is corrected. it can. As a result, the angle detection device can improve the detection accuracy of the rotation angle of the first multipole magnet.

  As a desirable mode of the angle detection device, the first distance correlation value is a value of the magnetic flux density detected by the first magnetic sensor, and the second distance correlation value is a value of the magnetic flux density detected by the second magnetic sensor. It is a value.

  According to this, it is possible to calculate based on the magnetic flux density detected by the first magnetic sensor and the magnetic flux density detected by the second magnetic sensor, and to improve the detection accuracy of the rotation angle of the first multipole magnet.

  As a desirable mode of the angle detection device, the distance displacement Δg1 between the first magnetic sensor and the first multipole magnet shown in the following formula (1), the second magnetic sensor shown in the following formula (2), and the first The first correction angle of the first multipole magnet is calculated such that the distance displacement Δg2 with the multipole magnet becomes zero.

Here, B _im1 is a value of the magnetic flux density detected by the first magnetic sensor, and B _io1 is that the distance between the first magnetic sensor and the first multipole magnet is a first reference distance amount In the case, the value of the magnetic flux density detected by the first magnetic sensor, B _im2 is the value of the magnetic flux density detected by the second magnetic sensor, and B _io2 is the value of the second magnetic sensor and the first magnetic sensor. When the distance to the multipolar magnet is a second reference distance amount, it is a value of the magnetic flux density detected by the second magnetic sensor, and K _i is a predetermined constant other than zero.

  According to this, it is possible to calculate based on the magnetic flux density detected by the first magnetic sensor and the magnetic flux density detected by the second magnetic sensor to improve the detection accuracy of the rotation angle of the first multipole magnet.

  As a desirable mode of the angle detection device, the first distance correlation value is obtained based on an electrical angle detected by the first magnetic sensor, and a distance between the first magnetic sensor and the first multipolar magnet. The second distance correlation value is inversely proportional to the amount, the second distance correlation value is determined based on the electrical angle detected by the second magnetic sensor, and is inversely proportional to the distance between the second magnetic sensor and the first multipole magnet. Do.

  According to this, it is possible to calculate based on the electrical angle detected by the first magnetic sensor and the electrical angle detected by the second magnetic sensor, and to improve the detection accuracy of the rotation angle of the first multipole magnet.

As a desirable mode of the angle detection device, the distance displacement Δg1 between the first magnetic sensor and the first multipole magnet shown in the following formula (3), the second magnetic sensor shown in the following formula (4), and the first The first correction angle of the first multipole magnet is calculated so that the distance displacement Δg2 to the multipole magnet becomes 0, and the first distance correlation value P _im1 is _expressed by the following formula (5) and the following formula The second distance correlation value P _im2 satisfies the following Expression (6) and the following Expression (8).

Here, sin θ _ie1 and cos θ _ie1 are functions of the electrical angle detected by the first magnetic sensor, and sin θ _ie2 and cos θ _ie2 are functions of the electrical angle detected by the second magnetic sensor, and sin θ _io1 and cos θ _io 1 is a function of an electrical angle detected by the first magnetic sensor when the distance between the first magnetic sensor and the first multipole magnet is a first reference distance amount, and the first distance correlation is the value _{P io1,} the distance between the first magnetic sensor and the first multi-pole magnet is a first distance correlation value _{P im1} in the case of the first reference distance amount, sin [theta _io2 and cos [theta] _io2, the first in case the distance between the two magnetic sensors first multi-pole magnet is in the second reference distance amount is a function of the electrical angle and the second magnetic sensor detects a second distance correlation value P _io2 is Serial distance between the second magnetic sensor and the first multi-pole magnet is a second distance correlation value _{P im2} in the case of the second reference distance _amount, K i, _{K 1,} and _{K 2} are, respectively, 0 It is a predetermined constant other than.

  According to this, it is possible to calculate based on the electrical angle detected by the first magnetic sensor and the electrical angle detected by the second magnetic sensor, and to improve the detection accuracy of the rotation angle of the first multipole magnet.

  As a desirable mode of the angle detection device, the first distance correlation value is obtained based on the magnetic flux density detected by the first magnetic sensor, and a distance between the first magnetic sensor and the first multipole magnet. In proportion to the amount, the second distance correlation value is determined based on the magnetic flux density detected by the second magnetic sensor, and is proportional to the distance between the second magnetic sensor and the first multipole magnet. Do.

  According to this, it is possible to calculate based on the magnetic flux density detected by the first magnetic sensor and the magnetic flux density detected by the second magnetic sensor to improve the detection accuracy of the rotation angle of the first multipole magnet.

  As a desirable mode of the angle detection device, the first distance correlation value is obtained based on an electrical angle detected by the first magnetic sensor, and a distance between the first magnetic sensor and the first multipolar magnet. In proportion to the amount, the second distance correlation value is determined based on the electrical angle detected by the second magnetic sensor, and is proportional to the distance between the second magnetic sensor and the first multipole magnet. Do.

  According to this, it is possible to calculate based on the electrical angle detected by the first magnetic sensor and the electrical angle detected by the second magnetic sensor, and to improve the detection accuracy of the rotation angle of the first multipole magnet.

  As a desirable mode of the angle detection device, the first multipole magnet has the same pitch of the respective magnetic poles, and a rotation reference which is a reference of a predetermined first shaft or a rotation center of the first multipole magnet. An angle formed by a line segment drawn from a position to a detection reference position of the first magnetic sensor and a detection reference position of the second magnetic sensor is an angle obtained by integral multiples of a mechanical angle of one magnetic pole pair of the first multipole magnet And an abnormality detection unit capable of detecting that at least one of the first magnetic sensor and the second magnetic sensor is abnormal by comparing the first angle and the second angle. According to this, it is possible to detect that at least one of the first magnetic sensor and the second magnetic sensor is abnormal.

  As a desirable mode of the angle detection device, a first gear rotating in synchronization with the first multipole magnet, a second gear meshing with the first gear, and rotationally driven by the rotation of the first gear, and a cylindrical shape A magnet that is magnetized in the radial direction of the cylinder and rotates integrally with the second gear; and an angle magnetic sensor disposed on the rotation axis of the magnet, the angle magnetic sensor comprising one of the magnets It is preferable that a signal of one cycle is output as a change in magnetic field of rotation, and the product of the gear ratio of the second gear to the first gear and the number of magnetic poles of the first multipole magnet is other than two. According to this, the number of rotations of the first multipole magnet can be calculated. More preferably, the angle correction unit executes a vernier operation from the signal of the angle magnetic sensor and the first angle, and the rotation angle of the first multipole magnet is 360 degrees or less, or the first multipole The rotation angle of the magnet over 360 degrees is calculated as an absolute angle.

  As a desirable mode of the angle detection device, a radius from a reference rotation axis of the first shaft or the first multipole magnet to a detection reference position of the first magnetic sensor is a detection of the second magnetic sensor from the reference rotation axis Preferably, it is the same as the radius to the reference position.

  The first magnetic sensor and the second magnetic sensor are arranged in a straight line when viewed in the axial direction of the first shaft, and the first magnetic sensor and the second multipole magnet are rotated from a reference rotation axis of the first shaft or the first multipole magnet. Preferably, the radius to the detection reference position is different from the radius from the reference rotation axis to the detection reference position of the second magnetic sensor.

  The relative angle detection device according to one aspect of the present invention is rotated in conjunction with the rotation of the first shaft, the second shaft, and the second shaft, which is the above-described angle detection device, of the second shaft A second multipole magnet in which different magnetic poles are alternately arranged along a circumferential direction, a third magnetic sensor disposed on the outer circumferential side of the second multipole magnet, and an outer circumferential side of the second multipole magnet And a fourth magnetic sensor, wherein the third magnetic sensor and the fourth magnetic sensor are different from the 180 ° symmetrical position with respect to the second multipole magnet, and the periphery of the second multipole magnet Are disposed at different positions in the circumferential direction, and the third magnetic sensor can output a third distance correlation value according to a third distance to the second multipole magnet, and the fourth magnetic sensor is configured to It is possible to output the fourth distance correlation value according to the fourth distance to the second multipole magnet The angle correction unit is configured to adjust a third angle detected by the third magnetic sensor according to the rotation of the second multipole magnet, the third distance correlation value, and the rotation of the second multipole magnet. A second angle detection device that calculates a second correction angle of the second multipole magnet based on a fourth angle detected by a fourth magnetic sensor and the fourth distance correlation value; the first correction angle; And a difference operation unit that calculates a relative rotation angle between the first multipole magnet and the second multipole magnet from a difference between the second correction angle and the second correction angle.

  According to this, the relative angle detection device can increase the accuracy of the relative rotation angle from the difference between the first correction angle in which the error is corrected and the second angle in which the error is corrected.

  A torque sensor according to an aspect of the present invention includes: a torsion bar; the relative angle detection device described above that detects the relative rotation angle of one end of the torsion bar and the other end of the torsion bar; And a torque calculation unit that calculates a torque applied to the torsion bar based on the relative rotation angle calculated by the relative angle detection device. Thereby, detection accuracy of torque can be raised.

  An electric power steering apparatus according to an aspect of the present invention includes the torque sensor described above. Thus, the current value supplied to the motor can be controlled based on the torque calculated with high accuracy. As a result, the electric power steering apparatus can output the assist steering torque with less discomfort.

  A vehicle according to an aspect of the present invention includes the above-described electric power steering device. According to the vehicle, since the electric power steering apparatus outputs the correct assist steering torque, the operability is improved.

  According to the present invention, it is possible to provide an angle detection device, a relative angle detection device, a torque sensor, an electric power steering device, and a vehicle capable of detecting an angle more accurately.

FIG. 1 is a perspective view schematically showing a vehicle equipped with the electric power steering apparatus according to the first embodiment. FIG. 2 is a schematic view of the electric power steering apparatus according to the first embodiment. FIG. 3 is a schematic view showing a functional block of the torque sensor according to the first embodiment. FIG. 4 is a perspective view schematically showing the torque sensor according to the first embodiment. FIG. 5 is a plan view schematically showing a rotation angle sensor that outputs the rotation angle of the input shaft according to the first embodiment. FIG. 6 is an explanatory view for explaining the direction of the magnetic flux penetrating the first magnetic sensor according to the first embodiment. FIG. 7 is an explanatory view for explaining the principle of detection of rotation by the first magnetic sensor according to the first embodiment. FIG. 8 is a conceptual diagram showing the magnetic flux density detected by the first magnetic sensor according to the first embodiment. FIG. 9 is a plan view schematically showing a rotation angle sensor when the input shaft of the torque sensor according to the first embodiment is displaced from the reference rotation shaft. FIG. 10 is a plan view schematically showing a rotation angle sensor that outputs the rotation angle of the output shaft according to the first embodiment. FIG. 11 is a plan view schematically showing a rotation angle sensor when the output shaft of the torque sensor according to the first embodiment is displaced from the reference rotation shaft. FIG. 12 is a flowchart showing a procedure of calculating a steering torque by the torque sensor according to the first embodiment. FIG. 13 is a flowchart illustrating a procedure in which the abnormality detection unit according to the first embodiment detects an abnormality in the rotation angle sensor. FIG. 14 is an explanatory diagram for describing a method of detecting an abnormality of the first magnetic sensor and the second magnetic sensor according to the first embodiment. FIG. 15 is a schematic view showing a functional block of the torque sensor according to the second embodiment. FIG. 16 is a plan view schematically showing the rotation angle sensor according to the second embodiment. FIG. 17 is a plan view schematically showing the rotation angle sensor according to the second embodiment. FIG. 18 is a plan view schematically showing a rotation angle sensor that outputs a rotation angle of an input shaft according to a first modification of the second embodiment. FIG. 19 is a plan view schematically showing a rotation angle sensor when an input shaft of a torque sensor according to a first modification of the second embodiment is displaced. FIG. 20 is a plan view schematically showing a rotation angle sensor that outputs the rotation angle of the output shaft according to the first modification of the second embodiment. FIG. 21 is a plan view schematically showing a rotation angle sensor when an output shaft of a torque sensor according to a first modification of the second embodiment is displaced. FIG. 22 is a plan view schematically showing a rotation angle sensor according to a second modification of the second embodiment. FIG. 23 is a plan view schematically showing a rotation angle sensor according to a third modification of the second embodiment. FIG. 24 is a schematic view showing a functional block of a torque sensor according to a third embodiment. FIG. 25 is a flowchart showing a procedure of calculating a steering torque by the torque sensor according to the third embodiment. FIG. 26 is an explanatory diagram for explaining a first correlation value according to the distance of the first magnetic sensor according to the third embodiment. FIG. 27 is an explanatory diagram for describing a second correlation value according to the distance of the second magnetic sensor according to the third embodiment. FIG. 28 is an explanatory view for explaining output characteristics of the first magnetic sensor or the second magnetic sensor according to the third embodiment. FIG. 29 is an explanatory diagram for describing a first magnetic sensor according to a modification of the third embodiment. FIG. 30 is an explanatory view for explaining output characteristics of the first magnetic sensor or the second magnetic sensor according to the modification of the third embodiment. FIG. 31 is a schematic view showing a functional block of a torque sensor according to a fourth embodiment. FIG. 32 is a flowchart showing a procedure of calculating a steering torque by the torque sensor according to the fourth embodiment. FIG. 33 is an explanatory diagram for explaining a first correlation value according to the distance of the first magnetic sensor according to the fourth embodiment. FIG. 34 is an explanatory diagram for explaining a first correlation value according to the distance of the first magnetic sensor according to the modification of the fourth embodiment. FIG. 35 is a perspective view schematically showing a torque sensor according to the fifth embodiment. FIG. 36 is a plan view for explaining the positional relationship between the angle magnetic sensor and the magnet according to the fifth embodiment. FIG. 37 is a schematic view showing a functional block of the torque sensor according to the fifth embodiment. FIG. 38 is an explanatory view showing a relationship between a first angle and angle magnetic sensor detection angle according to Embodiment 5 and a magnetic pole of a first multipole magnet.

  Hereinafter, modes for carrying out the invention (hereinafter referred to as embodiments) will be described in detail with reference to the drawings. Note that the present invention is not limited by the following embodiments. Further, constituent elements in the following embodiments include those which can be easily conceived by those skilled in the art, those substantially the same, and so-called equivalent ranges. Furthermore, the components disclosed in the following embodiments can be combined as appropriate.

(Embodiment 1)
FIG. 1 is a perspective view schematically showing a vehicle equipped with the electric power steering apparatus according to the first embodiment. FIG. 2 is a schematic view of the electric power steering apparatus according to the first embodiment. As shown in FIG. 1, the vehicle 101 is equipped with an electric power steering device 80. As shown in FIG. 2, in the electric power steering apparatus 80, the steering wheel 81, the steering shaft 82, the steering force assist mechanism 83, the universal joint 84, and the lower shaft 85 are transmitted in the order of transmission of the force applied by the operator. And a universal joint 86, and is joined to the pinion shaft 87.

  As shown in FIG. 2, the steering shaft 82 includes an input shaft 82 a and an output shaft 82 b. One end of the input shaft 82a is connected to the steering wheel 81, and the other end of the input shaft 82a is connected to the output shaft 82b. Further, one end of the output shaft 82b is connected to the input shaft 82a, and the other end of the output shaft 82b is connected to the universal joint 84. In the present embodiment, the input shaft 82a and the output shaft 82b are carbon steel for machine structure (SC material (Carbon Steel for Machine Structural Use)) or carbon steel tube for machine structure (so-called STKM material (Carbon Steel Tubes for Machine Structural Purposes) ) Etc. are formed from common steel materials etc.

  As shown in FIG. 2, the lower shaft 85 is a member connected to the output shaft 82 b via the universal joint 84. One end of the lower shaft 85 is connected to the universal joint 84 and the other end is connected to the universal joint 86. Further, one end of the pinion shaft 87 is connected to the universal joint 86, and the other end of the pinion shaft 87 is connected to the steering gear 88.

  As shown in FIG. 2, the steering gear 88 includes a pinion 88 a and a rack 88 b. The pinion 88 a is coupled to the pinion shaft 87. The rack 88 b meshes with the pinion 88 a. The steering gear 88 converts the rotational motion transmitted to the pinion 88a into a linear motion at the rack 88b. The rack 88 b is connected to the tie rod 89.

  As shown in FIG. 2, the steering force assist mechanism 83 includes a reduction gear 92 and a motor 93. The motor 93 is, for example, a brushless motor. The reduction gear 92 is, for example, a worm reduction gear. The torque generated by the motor 93 is transmitted to the worm wheel via the worm in the reduction gear 92 to rotate the worm wheel. The reduction gear 92 increases the torque generated by the motor 93 by means of a worm and a worm wheel (worm gear). Then, the reduction gear 92 applies an auxiliary steering torque to the output shaft 82b. The electric power steering apparatus 80 is a column assist system.

  The electric power steering apparatus 80 includes an ECU (Electronic Control Unit) 90 as a motor control apparatus, a rotation angle sensor 10 outputting a rotation angle of an input shaft 82a, and a rotation angle sensor 20 outputting a rotation angle of an output shaft 82b. , And a vehicle speed sensor 95. The vehicle speed sensor 95 is provided on the vehicle body, and outputs the vehicle speed SV as a signal to the ECU 90 by CAN (Controller Area Network) communication. Electric power is supplied to the ECU 90 from the power supply device 99 (for example, an on-board battery) while the ignition switch 98 is on. The ECU 90 acquires the rotation angle signal of the input shaft 82a output by the rotation angle sensor 10 and the rotation angle signal of the output shaft 82b output by the rotation angle sensor 20. The ECU 90 acquires the vehicle speed SV of the vehicle body from the vehicle speed sensor 95. The ECU 90 acquires information output from the rotation detection unit 23 as operation information SY. The ECU 90 calculates the assist steering command value based on the information of the steering torque based on the rotation angle signal acquired by the motor 93, the vehicle speed SV and the operation information SY. Then, the ECU 90 adjusts the power value SX supplied to the motor 93 based on the calculated assist steering command value.

  The steering force of the operator (driver) input to the steering wheel 81 is transmitted to the reduction gear 92 of the steering force assist mechanism 83 via the input shaft 82a. At this time, the ECU 90 acquires rotation angle signals of the input shaft 82a and the output shaft 82b, the vehicle speed SV, and the operation information SY. Then, the ECU 90 controls the operation of the motor 93. The assist steering torque generated by the motor 93 is transmitted to the reduction gear 92.

  The steering torque (including the auxiliary steering torque) output via the output shaft 82 b is transmitted to the lower shaft 85 via the universal joint 84 and further transmitted to the pinion shaft 87 via the universal joint 86. The steering force transmitted to the pinion shaft 87 is transmitted to the tie rod 89 via the steering gear 88 to displace the wheel.

(Torque sensor)
Next, the torque sensor 400 according to the first embodiment will be described with reference to FIGS. 3 to 5. FIG. 3 is a schematic view showing a functional block of the torque sensor according to the first embodiment. FIG. 4 is a perspective view schematically showing the torque sensor according to the first embodiment. FIG. 5 is a plan view schematically showing a rotation angle sensor that outputs the rotation angle of the input shaft according to the first embodiment.

As shown in FIG. 3, the torque sensor 400 includes a relative angle detection unit 300 and a torque calculation unit 402. The relative angle detection unit 300 can also be said to be a relative angle detection device that detects a relative angle Δθ _io that is a relative rotation angle between the input shaft 82 a and the output shaft 82 b. The relative angle detection unit 300 outputs the relative angle Δθ _io to the torque calculation unit 402. As shown in FIG. 4, the input shaft 82a and the output shaft 82b are connected by a torsion bar 82c. The torsion bar 82c is, for example, an elastic member formed of a steel material.

As shown in FIG. 3, the torque calculation unit 402 calculates the steering torque T based on the relative angle Δθ _io . For example, the torque calculator 402 stores the relationship between the relative angle Δθ _io and the steering torque T, which is determined by the characteristics of the torsion bar 82c. The torque calculator 402 calculates the steering torque T based on the relative angle Δθ _io input from the relative angle detector 300 and the relationship between the stored relative angle Δθ _io and the steering torque T. The torque calculation unit 402 outputs the calculated steering torque T to the motor control unit 91. The motor control unit 91 is a control unit of the ECU 90 that adjusts the power value SX described above.

As shown in FIG. 3, the relative angle detection unit 300 detects the first correction angle θ _is , which is the rotation angle of the input shaft 82a whose error has been corrected, and the output after the error is corrected. A second angle detection unit 200 that detects a second correction angle θ _os that is a rotation angle of the shaft 82b, and a difference calculation unit 302. The difference calculation unit 302 calculates the relative angle Δθ _io by calculating the difference between the first correction angle θ _is and the second correction angle θ _os .

  As shown in FIG. 3, the first angle detection unit 100 includes a rotation angle sensor 10, a storage unit 102, an angle correction unit 104 on the input shaft side, and an abnormality detection unit 106. As shown in FIG. 4, the rotation angle sensor 10 includes a first multipole magnet 12, a substrate 14, a first magnetic sensor 16 on the input shaft side (hereinafter referred to as the first magnetic sensor 16), and an input shaft side. And a second magnetic sensor 18 (hereinafter referred to as a second magnetic sensor 18).

  As shown in FIG. 4, the first multipole magnet 12 is, for example, a ring-shaped magnet magnetized in the radial direction. The first multipole magnet 12 has alternately arranged south poles and north poles on a circular outer peripheral surface in plan view. The number m of magnetic poles of the first multipole magnet 12 is, for example, 20, but is not limited thereto.

The reference rotation axis Ax0 shown in FIGS. 4 and 5 indicates a rotation axis when the rotation axis of the input shaft 82a or the output shaft 82b rotates without an error. The reference rotation axis Ax0 is a reference of the rotation center of the input shaft 82a which is the first shaft, the output shaft 82b which is the second shaft, the first multipole magnet 12 or the second multipole magnet 22, It is a rotation axis in the case where there was no _i .

  As shown in FIG. 4, the first multipole magnet 12 is attached to an end of the input shaft 82a on the side of the output shaft 82b, for example, so as to be coaxial with the rotation shaft of the input shaft 82a. For the first multipole magnet 12, for example, a neodymium magnet, a ferrite magnet, a samarium cobalt magnet or the like is used according to the required magnetic flux density. The rotational position of the first multipole magnet 12 shown in FIG. 5 indicates a reference position. In the reference position, the rotation axis of the input shaft 82a or the rotation center of the first multipole magnet 12 is at the reference rotation axis Ax0, and the first multipole magnet 12, the first magnetic sensor 16, and the second magnetic sensor 18 It is in the fixed position. Similarly, at the reference position, the rotation axis of the output shaft 82b or the rotation center of the second multipole magnet 22 is at the reference rotation axis Ax0, and the second multipole magnet 22, the third magnetic sensor 26, and the fourth magnetic sensor 28 are in a predetermined position. For example, in FIG. 5, the reference position indicates the position where the first magnetic sensor 16 and the second magnetic sensor 18 face the boundary between the N pole and the S pole of the first multipole magnet 12.

  As shown in FIG. 3, the second angle detection unit 200 includes a rotation angle sensor 20, an angle correction unit 204 on the output shaft side, and an abnormality detection unit 206. As shown in FIG. 4, the rotation angle sensor 20 includes a second multipole magnet 22, a substrate 24, a third magnetic sensor 26 on the output shaft side (hereinafter referred to as the third magnetic sensor 26), and an output shaft side. And a fourth magnetic sensor 28 (hereinafter referred to as a fourth magnetic sensor 28).

  As shown in FIG. 4, the second multipole magnet 22 is attached to the end of the output shaft 82b on the side of the input shaft 82a, and rotates with the first multipole magnet 12 except that it rotates in synchronization with the output shaft 82b. It is similar. That is, the second multipole magnet 22 has the same number of magnetic poles and the same pitch as the first multipole magnet 12. The number of magnetic poles and the pitch of the magnetic poles of the second multipole magnet 22 may be different from that of the first multipole magnet 12.

  As shown in FIG. 5, the first magnetic sensor 16 and the second magnetic sensor 18 are disposed on a first circle C1 of a radius R centered on the reference rotation axis Ax0, and the outer periphery of the first multipole magnet 12 It is disposed on the substrate 14 so as to face the surface. The arrangement of the first magnetic sensor 16 and the second magnetic sensor 18 on the first circle C1 means that the detection reference positions 16P and 18P of the respective sensors are located on the first circle C1. The substrate 14 is fixed to, for example, a vehicle body. The straight line L0 shown in FIG. 5 is a straight line drawn from the reference rotation axis Ax0 in the reference direction of the rotation of the first multipole magnet 12. The reference direction of rotation is set for convenience to determine the reference direction of rotation of the first multipole magnet 12, and may be set arbitrarily. A straight line L1 shown in FIG. 5 is a line segment connecting the reference rotation axis Ax0 and the detection reference position 16P. A straight line L2 shown in FIG. 5 is a line segment connecting the reference rotation axis Ax0 and the detection reference position 18P. The direction 46 shown in FIG. 5 is the radial direction of the reference rotation axis Ax0. That is, the direction 46 is a direction in which the first multipole magnet 12 and the first magnetic sensor 16 and the second magnetic sensor 18 approach or separate from each other. The direction 48 shown in FIG. 5 is orthogonal to the direction 46.

  As shown in FIG. 4, the third magnetic sensor 26 and the fourth magnetic sensor 28 are disposed on the second circle C2 of the radius R with the detection reference positions 26P and 28P centered on the reference rotation axis Ax0, and It is disposed on the substrate 24 so as to face the outer peripheral surface of the two multipole magnet 22. The substrate 24 is fixed to, for example, a vehicle body. The radius of the first circle C1 and the radius of the second circle C2 may have different lengths.

  FIG. 6 is an explanatory view for explaining the direction of the magnetic flux penetrating the first magnetic sensor according to the first embodiment. Magnetic lines of force 12 m shown in FIG. 6 indicate lines of magnetic force of the first multipole magnet 12.

  As shown in FIG. 6, the direction of the magnetic line of force 12m penetrating the detection reference position 16P of the first magnetic sensor 16 makes one rotation each time the first multipole magnet 12 rotates by one magnetic pole pair. The rotation of the first multipole magnet 12 by one magnetic pole pair corresponds to rotation by 36 degrees at the mechanical angle of the input shaft 82a in the first embodiment in which the number of magnetic poles is 20. That is, the direction of the magnetic flux passing through the detection reference position 16P of the first magnetic sensor 16 changes periodically due to the rotation of the first multipole magnet 12.

As shown in FIG. 5, the first magnetic sensor 16 and the second magnetic sensor 18 are disposed at positions separated by a mechanical angle for two magnetic pole pairs in the circumferential direction of the outer peripheral surface of the first multipole magnet 12 . The positions of the first magnetic sensor 16 and the second magnetic sensor 18 may be different from the 180 ° symmetrical position with the first multipole magnet 12 interposed therebetween. The straight line L1, the angle phi ₁ formed by the straight line L2 shows the first magnetic sensor 16 a relative positional relationship between the second magnetic sensor 18. Angle phi ₁ is the straight line L1, the straight line L2 are arbitrary should match the 0 ° or 180 °. As a result, the first magnetic sensor 16 and the second magnetic sensor 18 are disposed at different positions around the first multipole magnet 12.

Thus, the straight line L0, and the angle theta ₁ between the straight line L1, the straight line L0, and the angle theta ₂ between the straight line L2, as shown in FIG. 5, the input shaft 82a or the first multi-pole magnet 12 It is a known angle in the case of rotating without error on the reference rotation axis Ax0.

The angle φ ₁ is preferably an integral multiple of the mechanical angle of one magnetic pole pair of the first multipole magnet 12 except 0 ° or 180 °. Thereby, the directions of the magnetic fluxes passing through the first magnetic sensor 16 and the second magnetic sensor 18 can be aligned. As a result, the phase of the angle signal output from the first magnetic sensor 16 can be matched with the phase of the angle signal output from the second magnetic sensor 18.

  The memory of the storage unit 102 is volatile or non-volatile, such as random access memory (RAM), read only memory (ROM), flash memory, erasable programmable read only memory (EPROM), and electrically erasable programmable read only memory (EEPROM). Semiconductor memories, magnetic disks, flexible disks, optical disks, compact disks, mini disks, and DVDs (Digital Versatile Disc) are applicable.

  The first magnetic sensor 16, the second magnetic sensor 18, the third magnetic sensor 26, and the fourth magnetic sensor 28 are, for example, circular vertical Hall sensors. The circular vertical Hall sensor is a sensor that internally includes a plurality of Hall elements arranged on the circumference, and that can detect a change in the direction of the magnetic flux. The circular vertical Hall sensor can output an angle signal corresponding to the penetration direction of the magnetic flux density by detecting the magnetic flux density penetrating the detection reference position of the circular vertical Hall sensor.

The principle by which the first magnetic sensor 16 detects the rotation of the first multipole magnet 12 will be described with reference to FIGS. 7 and 8. FIG. 7 is an explanatory view for explaining the principle of detection of rotation by the first magnetic sensor according to the first embodiment. The magnetic flux density B shown in FIG. 7 is an example of the magnetic flux density passing through the detection reference position 16P. The sensor detection reference direction D shown in FIG. 7 is a reference direction of the direction of the magnetic flux density detected by the first magnetic sensor 16. The first electrical angle θ _ie1 shown in FIG. 7 is an angle _formed by the sensor detection reference direction D and the magnetic flux density B.

  As described above, the first magnetic sensor 16 is a circular vertical Hall sensor. As shown in FIG. 7, for example, the first magnetic sensor 16 internally includes Hall elements h1 to h24 arranged at equal intervals on the circumference around the detection reference position 16P. The Hall element h1 can detect the magnetic flux density in the direction from the detection reference position 16P toward the Hall element h1. The Hall element h2 to the Hall element h24 can detect the magnetic flux density in the direction from the detection reference position 16P to each Hall element, similarly to the Hall element h1.

FIG. 8 is a conceptual diagram showing the magnetic flux density detected by the first magnetic sensor according to the first embodiment. When the magnetic flux density B shown in FIG. 7 penetrates the detection reference position 16P, the magnetic flux density B _h1 to the magnetic flux density B _h24 shown in FIG. 8 indicate the values of the magnetic flux density detected by the Hall element h1 to the Hall element h24, respectively. . That is, the vertical axis in FIG. 8 indicates the magnitude of the magnetic flux density. The maximum magnetic flux density B _im shown in FIG. 8 is the maximum value from the magnetic flux density B _h1 to the magnetic flux density B _h24 . The conceptual diagram shown in FIG. 8 plots the magnetic flux density B _h1 to the magnetic flux density B _h24 at intervals of 15 degrees, with the horizontal axis as the angle θ.

The Hall elements h1 to h24 are arranged at an interval of 15 degrees on a circle centered on the detection reference position 16P with the sensor detection reference direction D as a reference. That is, the angle θ corresponds to the circumferential position at which the Hall elements h1 to h24 are arranged. As shown in FIGS. 7 and 8, the magnetic flux density B _h5 outputted by the Hall element h5 positioned in the direction of the magnetic flux density B has the largest value among the magnetic flux density B _h1 to the magnetic flux density B _h24 . Thus, the position of the Hall element for detecting the maximum magnetic flux density B _im represents the direction of the magnetic flux density B.

The first magnetic sensor 16 stores the correspondence between the magnetic flux density B _h1 to the magnetic flux density B _h24 and the angle θ shown in FIG. As shown in FIGS. 3 and 8, the first magnetic sensor 16 sets the position (angle θ) of the Hall element at which the maximum magnetic flux density B _im is detected as the first electrical angle θ _ie1 , and the angle correction unit 104 and the abnormality detection unit Output to 106. The first magnetic sensor 16 outputs the maximum magnetic flux density B _im to the angle correction unit 104. The first magnetic sensor 16 calculates the angle between the Hall elements from the maximum magnetic flux density B _im and the magnetic flux density of the Hall elements adjacent to the Hall element that has detected the maximum magnetic flux density B _im to calculate the first electrical angle. The θ _{ie 1} may be complementarily calculated.

The first magnetic sensor 16 scans the magnetic flux density of the Hall element h1 to the Hall element h24, and outputs the largest value of the magnetic flux density B _h1 to the magnetic flux density B _h24 . Therefore, when the magnetic field around the first magnetic sensor 16 changes, the value of the magnetic flux density having the largest value is output. The first magnetic sensor 16 scans the magnetic flux density of the Hall element h1 to the Hall element h24, and updates the output value for each scan. The updated output value is the maximum magnetic flux density B _im detected by the first magnetic sensor 16. Therefore, the first magnetic sensor 16 can always output the output value of the maximum magnetic flux density B _im regardless of the direction of the magnetic flux.

As described above, the first magnetic sensor 16 outputs a signal of the first angle θ _ie1 to the angle correction unit 104 and the abnormality detection unit 106. The first angle θ _ie1 is an electrical angle. The second magnetic sensor 18 outputs a signal of the second angle θ _ie2 to the angle correction unit 104 and the abnormality detection unit 106. The second angle θ _ie2 is an electrical angle. The third magnetic sensor 26 outputs a signal of the third angle θ _oe1 to the angle correction unit 204 and the abnormality detection unit 206. The third angle θ _oe1 is an electrical angle. The fourth magnetic sensor 28 outputs a signal of the fourth angle θ _oe2 to the angle correction unit 204 and the abnormality detection unit 206. The fourth angle θ _oe2 is an electrical angle.

As shown in FIG. 3, the first magnetic sensor 16 outputs the detected maximum magnetic flux density B _im as a signal of the magnetic flux density B _im1 to the angle correction unit 104. The second magnetic sensor 18, the third magnetic sensor 26 and the fourth magnetic sensor 28 are also similar to the first magnetic sensor 16.

In addition, the second magnetic sensor 18 outputs a signal of the detected magnetic flux density B _im2 to the angle correction unit 104. The third magnetic sensor 26 outputs a signal of the detected magnetic flux density B _om1 to the angle correction unit 204. The fourth magnetic sensor 28 also outputs a signal of the detected magnetic flux density B _{om 2} to the angle correction unit 204.

Next, with reference to FIG. 3, FIG. 5, FIG. 9, and FIG. 12, a method for the angle correction unit 104 to calculate the first correction angle θ _is which is the rotation angle of the input shaft 82a will be described.

In the case where the input shaft 82a or the first multipole magnet 12 rotates on the reference rotation axis Ax0 without error, the first angle θ _ie1 matches the first angle θ _io1 and the magnetic flux density B _ie1 becomes the magnetic flux density B _io1 Match Further, in the case where the input shaft 82a or the first multipole magnet 12 rotates without error on the reference rotation axis Ax0, the second angle θ _ie2 matches the second angle θ _io2 , and the magnetic flux density B _ie2 is the magnetic flux density Match B _io2 . Mechanical angle of the first angle theta _io1 is the first reference angle theta _1, mechanical angle of the second angle theta _io2 is a second reference angle theta _2.

  FIG. 9 is a plan view schematically showing a rotation angle sensor when the input shaft of the torque sensor according to the first embodiment is displaced from the reference rotation shaft. FIG. 12 is a flowchart showing a procedure of calculating a steering torque by the torque sensor according to the first embodiment.

As shown in FIG. 9, the input shaft 82a may be displaced under the influence of vibration when the vehicle 101 travels or a couple of forces applied from the lower shaft 85 or the like. When the rotation axis of the input shaft 82a or the first multipole magnet 12 is displaced from the reference rotation axis Ax0 to the rotation axis Ax1, the first angle θ _ie1 detected by the first magnetic sensor 16 may not match the first angle θ _io1 There is sex. When the rotation axis of the input shaft 82a or the first multipole magnet 12 is displaced from the reference rotation axis Ax0 to the rotation axis Ax1, the second angle θ _ie2 detected by the second magnetic sensor 18 may not match the second angle θ _io2 There is sex.

The rotation axis Ax1 shown in FIG. 9 is a rotation axis of the input shaft 82a when the position of the rotation axis of the input shaft 82a is displaced from the reference rotation axis Ax0. The straight line L3 shown in FIG. 9 is a straight line drawn from the reference rotation axis Ax0 toward the rotation axis Ax1. Displacement _{X i} shown in FIG. 9 is the distance between the reference rotational axis Ax0 and the rotation axis Ax1. Angle _{Y i} shown in FIG. 9, a straight line L3, which is the angle between the straight line L0. Error angle Z ₁ shown in FIG. 9 is an angle determined according to the distance measure gim1 the first magnetic sensor 16 and the first multi-pole magnet 12. Error angle Z ₂ shown in FIG. 9 is an angle determined according to the distance measure gim2 the second magnetic sensor 18 and the first multi-pole magnet 12.

Here, in the present embodiment, the first angle θ _ie1 is an electrical angle, and the angle correction unit 104 calculates the first angle θ _i1 of the mechanical angle based on the number m of magnetic poles and the first angle θ _ie1 . The electrical angle may be converted to a mechanical angle in the first magnetic sensor 16 and the first angle θ _i1 of the mechanical angle may be output to the angle correction unit 104. Further, the second angle θ _ie2 is an electrical angle, and the angle correction unit 104 calculates the second angle θ _i2 of the mechanical angle based on the number m of magnetic poles and the second angle θ _ie2 . The electrical angle may be converted to a mechanical angle in the second magnetic sensor 18, and the second angle _θi2 of the mechanical angle may be output to the angle correction unit 104.

The rotation angle of the first multipole magnet 12 corrected for an error due to the first displacement Xi relative to the reference rotation axis Ax0 of the input shaft 82a or the first multipole magnet 12 is referred to as a first correction angle θ _is In this case, the first angle θ _i1 can be expressed by the relationship between the angle θ ₁ , the error angle Z ₁ , and the first correction angle θ _is, and can be obtained by Expression (9). Similarly, the second angle θ _i2 can be obtained by equation (10).

Error angle _{Z 1} can be obtained by equation (11). Similarly, error angle _{Z 2} can be obtained by equation (12). Radius from the reference rotation axis Ax0 to detect the reference position 16P _{is R i1.} Radius from the reference rotation axis Ax0 to detect the reference position 18P _{is R i2.} In the first embodiment, the radius R _i1 and the radius R _i2 are the same radius R.

As shown in FIG. 5, in the case where the input shaft 82a or the first multipole magnet 12 rotates without error on the reference rotation axis Ax0, the distance between the first magnetic sensor 16 and the first multipole magnet 12 gim1 is separated by a first reference distance amount g1. In this case, the first magnetic sensor 16 detects the magnetic flux density _Bio1 . The magnetic flux density B _io1 is in inverse proportion to the square of the first reference distance amount g1 and therefore has a relationship of the following equation (13). The constant K _i is a predetermined constant other than zero.

As shown in FIG. 5, in the case where the input shaft 82a or the first multipole magnet 12 rotates without error on the reference rotation axis Ax0, the distance between the second magnetic sensor 18 and the first multipole magnet 12 gim2 is separated by a second reference distance amount g2. In this case, the second magnetic sensor 18 detects the magnetic flux density _Bio2 . The second reference distance amount g2 and the magnetic flux density _Bio2 are in the relationship of the following equation (14).

  The above equation (13) can be made to be the following equation (15).

  The above equation (14) can be made to be the following equation (16).

When the rotation axis of the input shaft 82a or the first multipole magnet 12 is displaced from the reference rotation axis Ax0 to the rotation axis Ax1, the magnetic flux density _Bio1 detected by the first magnetic sensor 16 changes to the magnetic flux density _Bim1 . For this reason, the distance amount gim1 is expressed by the following equation (17).

If the rotation axis of the input shaft 82a or the first multi-pole magnet 12 is displaced in the rotational axis Ax1 from the reference rotation axis Ax0, the magnetic flux density _{B io2} the second magnetic sensor 18 detects changes in the magnetic flux density _{B im2.} Therefore, the distance amount gim2 is expressed by the following equation (18).

  The distance displacement Δg1 between the first magnetic sensor 16 and the first multipole magnet 12 can be obtained by the equation (19) based on the equations (15) and (17).

  The distance displacement Δg2 between the second magnetic sensor 18 and the first multipole magnet 12 can be determined by equation (20) based on the equations (16) and (18).

Here, a displacement _{X i} described above, at an angle _{Y i,} define variables α and the variable β by the following formula (21) and (22).

Further, the above-described Δg ₁ can be expressed by the following equation (23) using the displacement X _i , the angle Y _i , and the angle θ ₁ . Then, .DELTA.G1, based on the equation (21) and the formula (22), the variable alpha, the variable beta, and may be expressed using the angle theta _1.

Similarly, the above-mentioned Δg ₂ can be expressed by the following equation (24) using the displacement X _i , the angle Y _i , and the angle θ ₂ . Then, Δg ₂ can also be expressed using the variable α, the variable β, and the angle θ ₂ based on the above equation (21) and the above equation (22).

If information of the magnetic flux density B _im1 and information of the magnetic flux density B _im2 can be obtained from the equations (19) and (20), Δg1 is given to the equation (23), and Δg2 is given to the equation (24), The variables α and β can be determined. When the variable α and the variable β are given to the following equation (25), the angle Y _i can be obtained.

If the variables α and β are given to the following equation (26), the displacement X _i can be obtained.

Angle correction unit 104, the following equation (27) based on the above-described formula (9) and (11) gives the displacements _{X i} and the angle _{Y i} based on the equation (25) and the formula (26) The first correction angle θ _is is calculated. Alternatively, the angle corrector 104, the following equation (28) based on the above Expression (10) and (12), the displacement _{X i} and the angle _{Y i} based on the equation (25) and the formula (26) To calculate the first correction angle θ _is . As a result, the angle correction unit 104 is configured such that the error due to the first displacement Xi relative to the reference axis of rotation Ax0 of the input shaft 82a or the first multipole magnet 12 is corrected. 1 Correction angle θ _is can be calculated.

To explain with reference to FIG. 12, the angle correction unit 104 shown in FIG. 3, the first angle theta _ie1, second angle theta _ie2, magnetic flux density _{B im1,} and acquires the magnetic flux density _{B im2} (step ST11).

Next, the angle correction unit 104 calculates the first correction angle θ _is as described above based on the first angle θ _ie1 , the second angle θ _ie2 , the magnetic flux density B _im1 , and the magnetic flux density B _im2 (step ST12).

The angle correction unit 104 has an error angle Z ₁ due to relative displacement of the first magnetic sensor 16 and the first multipole magnet 12 or the rotation axis Ax1 in the direction 48, and the second magnetic sensor 18 and the first multipole magnet The first correction angle θ _is is calculated by correcting at least one of the error angles Z ₂ due to relative displacement of the rotation axis Ax 1 in the direction 48 or 12. According to this, even when the rotation axis of the first multipole magnet 12 is displaced from the reference rotation axis Ax0, the first angle detection unit 100 determines the rotation angle of the first multipole magnet 12 (first correction angle θ _is ). Can be calculated accurately.

As described above, the first angle detection unit 100 includes the input shaft 82a as the first shaft, the first multipole magnet 12, the first magnetic sensor 16, the second magnetic sensor 18, and the angle correction unit 104. And a first angle detection device. The first multipole magnet 12 rotates in conjunction with the rotation of the input shaft 82a. Then, due to the rotation of the first multipole magnet 12, the first magnetic sensor 16 and the second magnetic sensor 18 are disposed at circumferentially different positions around the first multipole magnet 12. The first magnetic sensor 16 outputs the detected first angle θ _ie1 and the first magnetic flux density which is the magnetic flux density B _im1 to the angle correction unit 104. The second magnetic sensor 18 outputs the detected second angle θ _ie2 and the second magnetic flux density that is the magnetic flux density B _im2 to the angle correction unit 104. In the first embodiment, the magnetic flux density B _im1 is a first distance correlation value according to the first distance between the first magnetic sensor 16 and the first multipole magnet 12. The magnetic flux density B _im2 is a second distance correlation value according to the second distance between the second magnetic sensor 18 and the first multipole magnet 12.

The angle correction unit 104 calculates a first correction angle θ _is based on the first angle θ _ie1 , the second angle θ _ie2 , the magnetic flux density B _im1 , and the magnetic flux density B _im2 . First correction angle theta _IS is the rotation angle of the first multi-pole magnet 12 or the input shaft 82a of at least one depending on the angle error of the error angle Z ₁ and error angle Z ₂ described above has been corrected. More specifically, the first correction angle θ _is is the distance displacement Δg1 between the first magnetic sensor 16 and the first multipole magnet 12 shown in the above equation (19), and the second magnetic angle shown in the above equation (20) The distance displacement Δg2 between the sensor 18 and the first multipole magnet 12 is calculated so as to be zero.

Thus, the first angle detector 100, the input shaft 82a or the error angle _{Z 1} and error angle _{Z 2} by relative first displacement Xi of the reference rotation axis Ax0 of the first multi-pole magnet 12 at least Correct one. As a result, the first angle detection unit 100 can improve the detection accuracy of the rotation angle of the first multipole 12.

According to the first embodiment, the rotation angle of the first multipole magnet 12 is detected based on the magnetic flux density B _im1 detected by the first magnetic sensor 16 and the magnetic flux density B _im2 detected by the second magnetic sensor 18. Accuracy can be improved.

  The first multipole magnet 12 does not have to rotate at the same speed as the rotation of the input shaft 82a and the rotation of the first multipole magnet 12 that the first multipole magnet 12 rotates in conjunction with the rotation of the input shaft 82a. There may be a gear mechanism of a predetermined gear ratio between the input shaft 82 a and the first multipole magnet 12.

At least bracts of error angle Z ₁ and error angle Z _2, 9 even if the displacement X _i shown in FIG. 9 occurs only in one of the first magnetic sensor 16 side or the second magnetic sensor 18 side If displacement X _i occurs in both the first magnetic sensor 16 side or the second magnetic sensor 18 side includes. In the present embodiment, the displacement X _i shown in FIG. 9 is the distance between the reference rotational axis Ax0 and the rotation axis Ax1. Displacement X _i shown in FIG. 9, if the reference rotational axis Ax0 and rotational axis Ax1 is not limited to parallel, rotational axis Ax1 is inclined with respect to the reference rotation axis Ax0, or first multipolar This may occur even when the rotation axis of the magnet 12 is inclined with respect to the reference rotation axis Ax0. In any of these cases, the first angle detection unit 100 sets the first correction angle θ _is corrected in the plane on which the first magnetic sensor 16 and the second magnetic sensor 18 are located as shown in FIG. It can be calculated accurately.

In addition, even if the distance between the reference rotation axis Ax0 and the rotation axis of the input shaft 82a is 0, the reference rotation axis Ax0 can be obtained if the rotation axis of the input shaft 82a and the rotation center of the first multipole magnet 12 deviate. If in the case where the rotation center of the first multi-pole magnet 12 as the rotation axis Ax1, the displacement X _i occurs as shown in FIG. Even in this case, the first angle detection unit 100 accurately calculates the first correction angle θ _is with respect to the plane on which the first magnetic sensor 16 and the second magnetic sensor 18 are present and in which the error due to the displacement Xi shown in FIG. can do.

Even if the rotation axis Ax1 of the first multipole magnet 12 is displaced in the axial direction of the rotation axis Ax1 as it is rotated, the displacement is smaller than the dimension of the first multipole magnet 12 in the axial direction. The influence of the displacement in the axial direction of the rotation axis Ax1 hardly affects the accuracy of the first correction angle θ _is .

The third magnetic sensor 26 shown in FIG. 3 outputs the third angle θ _oe1 and the magnetic flux density B _om1 to the angle correction unit 204 and the abnormality detection unit 206. The fourth magnetic sensor 28 _outputs the fourth angle θ _oe2 and the magnetic flux density B _om2 to the angle correction unit 204 and the abnormality detection unit 206.

When the output shaft 82b or the second multi-pole magnet 22 is rotating without error at the reference rotation axis Ax0, the third angle theta _oe1 matches the third angle theta _OO1, the magnetic flux density _{B ie1} is magnetic flux density _{B io1} Match Further, the output shaft 82b or, in the case where the second multi-pole magnet 22 is rotating without error at the reference rotation axis Ax0, fourth angle theta _oe2 matches the fourth angle theta _OO2, and the magnetic flux density is the magnetic flux density _{B ie2} Match B _io2 . Mechanical angle of the third angle theta _OO1 has a third reference angle theta _3, mechanical angle of the fourth angle theta _OO2 is fourth reference angle theta _4.

As illustrated in FIG. 12, the angle correction unit 204 illustrated in FIG. 3 _acquires the third angle θ _oe1 , the fourth angle θ _oe2 , the magnetic flux density B _om1 , and the magnetic flux density B _om2 (step ST21).

Next, the angle correction unit 204 calculates a second correction angle θ _os based on the third angle θ _oe1 , the fourth angle θ _oe2 , the magnetic flux density B _om1 , and the magnetic flux density B _om2 (step ST22).

  FIG. 10 is a plan view schematically showing a rotation angle sensor that outputs the rotation angle of the output shaft according to the first embodiment. FIG. 11 is a plan view schematically showing a rotation angle sensor when the output shaft of the torque sensor according to the first embodiment is displaced from the reference rotation shaft. A straight line L21 shown in FIG. 10 is a line connecting the reference rotation axis Ax0 and the detection reference position 26P. A straight line L22 shown in FIG. 10 is a line connecting the reference rotation axis Ax0 and the detection reference position 28P. A straight line L00 shown in FIG. 17 is a straight line drawn from the reference rotation axis Ax0 in the reference direction of the rotation of the second multipole magnet 22.

In case the output shaft 82a or the second multi-pole magnet 22 is rotating without error at the reference rotation axis Ax0, the third angle theta _oe1 matches the third angle theta _OO1, the magnetic flux density _{B om1} within the magnetic flux density _{B IO11} Match Further, in the case where the output shaft 82a or the second multipole magnet 22 rotates without error on the reference rotation axis Ax0, the fourth angle θ _oe2 matches the second angle θ _oo2 and the magnetic flux density B _om2 is the magnetic flux density _Matches B _io12 . Mechanical angle of the first angle theta _OO1 has a third reference angle theta _3, mechanical angle of the second angle theta _OO2 is fourth reference angle theta _4.

As shown in FIG. 10, the distance between the third magnetic sensor 26 and the second multipole magnet 22 when the output shaft 82b or the second multipole magnet 22 rotates without error on the reference rotation axis Ax0. gom11 is separated by a first reference distance amount g11. In this case, the second magnetic sensor 26 detects the magnetic flux density B _io11 . The magnetic flux density B _io11 is in inverse proportion to the square of the first reference distance amount g11, and therefore, is in the relationship of the following equation (29). The constant K _i is a predetermined constant other than zero.

As shown in FIG. 10, the distance between the fourth magnetic sensor 28 and the second multipole magnet 22 when the output shaft 82b or the second multipole magnet 22 rotates without error on the reference rotation axis Ax0. gom 12 is separated by a second reference distance amount g12. In this case, the fourth magnetic sensor 28 detects the magnetic flux density _Bio12 . The second reference distance amount g12 and the magnetic flux density _Bio12 are in the relationship of the following equation (30).

As shown in FIG. 11, the output shaft 82 b may be displaced under the influence of vibration when the vehicle 101 travels or a couple force applied from the lower shaft 85 or the like. When the rotation axis of the output shaft 82b or the second multipole magnet 22 is displaced from the reference rotation axis Ax0 to the rotation axis Ax1, the third angle θ _oe1 detected by the third magnetic sensor 26 may not match the third angle θ _oo1 There is sex. When the rotation axis of the output shaft 82b or the second multipole magnet 22 is displaced from the reference rotation axis Ax0 to the rotation axis Ax1, the fourth angle θ _oe2 detected by the fourth magnetic sensor 28 may not coincide with the second angle θ _oo2 There is sex.

A straight line L13 shown in FIG. 11 is a straight line drawn from the reference rotation axis Ax0 toward the rotation axis Ax1. Displacement _{X o} shown in FIG. 11 is the distance between the reference rotational axis Ax0 and the rotation axis Ax1. Angle _{Y o} shown in FIG. 11, a straight line L13, which is the angle between the straight line L00. Error angle _{Z 3} shown in FIG. 11 is an angle determined according to the distance measure gom1 the third magnetic sensor 26 and the second multi-pole magnet 22. Error angle _{Z 4} shown in FIG. 11 is an angle determined according to the distance measure gom2 the fourth magnetic sensor 28 and the second multi-pole magnet 22.

Here, in the present embodiment, the third angle theta _oe1 electrical angle, based on the number of magnetic poles m third angle theta _oe1, the angle corrector 204 calculates a first angle theta _o1 of mechanical angle. The electrical angle may be converted to a mechanical angle in the third magnetic sensor 26, and the first angle θ _o1 of the mechanical angle may be output to the angle correction unit 204. Further, the fourth angle θ _oe2 is an electrical angle, and the angle correction unit 204 calculates the fourth angle θ _o2 of the mechanical angle based on the number m of magnetic poles and the fourth angle θ _oe2 . The electrical angle may be converted to a mechanical angle in the fourth magnetic sensor 28, and the fourth angle θ _o2 of the mechanical angle may be output to the angle correction unit 204.

When the rotation axis of the output shaft 82b or the second multipole magnet 22 is displaced from the reference rotation axis Ax0 to the rotation axis Ax1, the magnetic flux density B _io11 detected by the third magnetic sensor 26 changes to the magnetic flux density B _om1 . For this reason, distance amount gom1 becomes following formula (31).

When the rotation axis of the output shaft 82b or the second multipole magnet 22 is displaced from the reference rotation axis Ax0 to the rotation axis Ax1, the magnetic flux density _Bio12 detected by the fourth magnetic sensor 28 changes to the magnetic flux density _Bom2 . For this reason, distance amount gom2 becomes following formula (32).

  The distance displacement Δg11 between the third magnetic sensor 26 and the second multipole magnet 22 can be determined by equation (33) based on the equations (29) and (31).

  The distance displacement Δg12 between the fourth magnetic sensor 28 and the second multipole magnet 22 can be determined by equation (34) based on the equations (30) and (32).

Here, the variable γ and the variable δ are defined by the following equation (35) and equation (36) with the displacement X _o and the angle Y _o .

Further, the above-described Δg 11 can be expressed by the following equation (37) using the displacement X _o , the angle Y _o , and the angle θ ₃ . Then, Derutaji11, the above formula (35) and the above formula based on the (36), a variable gamma, variable [delta], and can also be expressed using the angle theta _3.

Similarly, the above-described Δg12 can be expressed by the following equation (38) using the displacement X _o , the angle Y _o , and the angle θ ₄ . Then, Δg 12 can also be expressed using the variable γ, the variable δ, and the angle θ ₄ based on the above equation (35) and the above equation (36).

If information of the magnetic flux density B _om1 and information of the magnetic flux density B _om2 can be obtained from the equations (33) and (34), Δg1 is given to the equation (37), and Δg2 is given to the equation (38). The variable γ and the variable δ can be determined. When the variable γ and the variable δ are given to the following equation (39), the angle _Yo can be obtained.

If the variable γ and the variable δ are given to the following equation (40), the displacement X _o can be obtained.

The angle correction unit 204 gives the displacement X _o and the angle Y _o based on the equation (39) and the equation (40) to the following equation (41) to calculate a second correction angle θ _os . Alternatively, the angle correction unit 204 gives the displacement X _o and the angle Y _o based on the above equation (39) and the above equation (40) to the following equation (42) to calculate the second correction angle θ _os .

As a result, the angle correction unit 204 detects the error due to the second displacement X _o relative to the reference rotational axis Ax 0 of the output shaft 82 b or the second multipole magnet 22 of the second multipole magnet 22. The second correction angle θ _os can be calculated. As shown in FIG. 10, the radius from the reference rotation axis Ax0 to detect the reference position 26P _{is R o1.} Radius from the reference rotation axis Ax0 to detect the reference position 28P _{is R o2.} In the first embodiment, the radius R _o1 and the radius R _o2 are the same radius R.

As described above, the second angle detection unit 200 includes the output shaft 82b as the second shaft, the second multipole magnet 22, the third magnetic sensor 26, the fourth magnetic sensor 28, and the angle correction unit 204. And a second angle detection device. The second multipole magnet 22 rotates in conjunction with the rotation of the output shaft 82b. Then, the third magnetic sensor 26 and the fourth magnetic sensor 28 are disposed at circumferentially different positions around the second multipole magnet 22 by the rotation of the second multipole magnet 22. The third magnetic sensor 26 outputs the detected third angle θ _oe1 and the third magnetic flux density that is the magnetic flux density B _om1 to the angle correction unit 204. The fourth magnetic sensor 28 outputs the detected fourth angle θ _oe2 and the fourth magnetic flux density that is the magnetic flux density B _om2 to the angle correction unit 204. In the first embodiment, the magnetic flux density B _om1 is a third distance correlation value corresponding to the third distance between the third magnetic sensor 26 and the second multipole magnet 22. The magnetic flux density B _om2 is a fourth distance correlation value corresponding to the fourth distance between the fourth magnetic sensor 28 and the second multipole magnet 22.

The angle correction unit 204 calculates a second correction angle θ _os based on the third angle θ _oe1 , the fourth angle θ _oe2 , the magnetic flux density B _om1 , and the magnetic flux density B _om2 . The second correction angle θ _os is an angle error due to relative displacement of the rotational axis of the third magnetic sensor 26 and the second multipole magnet 22 or the output shaft 82b in the direction 48, and the fourth magnetic sensor 28 and the second multiple The rotation angle of the second multipole magnet 22 or the output shaft 82b is an angle error corrected by at least one of the angle errors due to relative displacement of the rotation axis of the pole magnet 22 or the output shaft 82b in the direction 48. According to this, the second angle detection unit 200 can calculate the second correction angle θ _os with the same action as the first angle detection unit 100.

  In the present embodiment, the detection reference position 16P of the first magnetic sensor 16 and the detection reference position 18P of the second magnetic sensor 18 are disposed on a first circle C1 of radius R centered on the reference rotation axis Ax0. The detection reference position 26P of the third magnetic sensor 26 and the detection reference position 28P of the fourth magnetic sensor 28 are disposed on a second circle C2 of radius R centered on the reference rotation axis Ax0. The distance at which the first magnetic sensor 16 and the second magnetic sensor 18 are disposed from the reference rotation axis Ax0 of the first multipole magnet 12 may be different. Further, the distance at which the third magnetic sensor 26 and the fourth magnetic sensor 28 are disposed from the reference rotation axis Ax0 of the second multipole magnet 22 may be different.

As shown in FIG. 12, the relative angle detection unit 300 shown in FIG. 3 calculates the relative angle Δθ _io based on the calculated first correction angle θ _is and the second correction angle θ _os (step ST31). In the present embodiment, the relative angle detection unit 300 is a relative angle detection device that calculates the relative angle Δθ _io between the input shaft 82a, which is the first shaft, and the output shaft 82b, which is the second shaft. In the relative angle Δθ _io , the above-mentioned error angle Z ₁ , error angle Z ₂ , an angle error due to relative displacement of the rotation axis of the third magnetic sensor 26 and the second multipole magnet 22 or the output shaft 82b in the direction Since at least one of the angular errors due to the relative displacement of the rotation axes of the fourth magnetic sensor 28 and the second multipole magnet 22 or the output shaft 82b is reduced, the accuracy is enhanced.

  The relative angle detection unit 300 according to the present embodiment includes an angle correction unit 204 separately from the angle correction unit 104, and the angle correction unit 104 and the angle correction unit 204 are respectively a first angle detection device or a second angle detection device. It functions as an angle correction unit. The angle correction unit 104 may perform the processing of the angle correction unit 204 without the above-described angle correction unit 204. Alternatively, the angle correction unit 204 may perform the processing of the angle correction unit 104 without the above-described angle correction unit 104.

As shown in FIG. 12, the torque sensor 400 shown in FIG. 3 calculates the steering torque T based on the relative angle Δθ _io calculated in step ST31 (step ST41). According to this, the torque sensor 400 can calculate the steering torque T. The steering torque T is an angular error due to the relative displacement of the rotational axis of the third magnetic sensor 26 and the second multipole magnet 22 or the output shaft 82b in the direction and the error angle Z ₁ and the error angle Z ₂ described above. Since at least one of the angular errors due to the relative displacement of the rotational axes of the four magnetic sensor 28 and the second multipole magnet 22 or the output shaft 82b in the direction is reduced, the accuracy is enhanced.

  As shown in FIG. 12, the torque calculation unit 402 shown in FIG. 3 outputs information on the steering torque T as a signal to the motor control unit 91 (step ST42). The motor control unit 91 calculates the assist steering command value based on the information of the steering torque T, the vehicle speed SV and the operation information SY. Then, motor control unit 91 adjusts electric power value SX supplied to motor 93 based on the calculated assist steering command value. As a result, the electric power steering device 80 can output the auxiliary steering torque with less discomfort to the operator.

  Next, with reference to FIG. 13 and FIG. 14, a method in which the abnormality detection unit 106 detects an abnormality of the first magnetic sensor 16 and the second magnetic sensor 18 will be described. FIG. 13 is a flowchart illustrating a procedure in which the abnormality detection unit according to the first embodiment detects an abnormality in the rotation angle sensor. FIG. 14 is an explanatory diagram for describing a method of detecting an abnormality of the first magnetic sensor and the second magnetic sensor according to the first embodiment.

As shown in FIG. 13, the abnormality detection unit 106 first executes comparison step ST51. In the comparison step ST51, the abnormality detection unit 106 detects an abnormality of the first magnetic sensor 16 and the second magnetic sensor 18 by comparing the first angle θ _ie1 with the second angle θ _ie2 . Specifically, as shown in FIG. 14, when the difference between the first angle θ _ie1 and the second angle θ _ie2 exceeds a predetermined threshold Th, as shown in FIG. And at least one of the second magnetic sensors 18 is detected as abnormal. T1 shown in FIG. 14 indicates the time when the difference between the first angle θ _ie1 and the second angle θ _ie2 exceeds the threshold value Th.

Next, abnormality detection unit 106 determines whether or not rotation angle sensor 10 is abnormal (step ST52). Specifically, the abnormality detection unit 106 determines that the rotation angle sensor 10 is not abnormal when the difference between the first angle θ _ie1 and the second angle θ _ie2 is equal to or smaller than the threshold Th (ST 52, Yes). .

  When the abnormality detection unit 106 determines that there is an abnormality in the rotation angle sensor 10 in step ST52 (No in step ST52), the abnormality detection unit 106 determines that continuous operation is not possible (step ST53). Specifically, the abnormality detection unit 106 outputs an operation continuation impossibility determination signal to the motor control unit 91. The motor control unit 91 displays an alert for the driver when the driving continuation impossible determination signal is input. According to this, when the first magnetic sensor 16 and the second magnetic sensor 18 fail, the driver can be notified of the failure. In addition, the motor control unit 91 stops the supply of power to the motor 93 when the operation continuation impossibility determination signal is input. According to this, when at least one of the first magnetic sensor 16 and the second magnetic sensor 18 fails, it is possible to prevent the motor control unit 91 from outputting the erroneous power value SX.

Similar to the abnormality detection unit 106, the abnormality detection unit 206 _compares the third angle θ _oe1 with the fourth angle θ _oe2 to detect an abnormality in the third magnetic sensor 26 and the fourth magnetic sensor 28. Therefore, the detailed description of the abnormality detection unit 206 is omitted.

  Although the angle correction unit 104, the abnormality detection units 106 and 206, the angle correction unit 204, the difference calculation unit 302, and the torque calculation unit 402 are included in the ECU 90, they may be arranged outside the ECU 90. Good.

Second Embodiment
FIG. 15 is a schematic view showing a functional block of the torque sensor according to the second embodiment. 16 and 17 are plan views schematically showing the rotation angle sensor according to the second embodiment. In addition, the same code | symbol is attached | subjected to the same component as what was demonstrated in Embodiment 1 mentioned above, and the overlapping description is abbreviate | omitted.

As shown in FIGS. 15 and 16, the rotation angle sensor 10 of the second embodiment includes a first magnetic sensor 16, a second magnetic sensor 18, and a fifth magnetic sensor 17. Radius from the reference rotation axis Ax0 to detect the reference position 16P _{is R i1.} Radius from the reference rotation axis Ax0 to detect the reference position 18P _{is R i2.} Radius from the reference rotation axis Ax0 to detect the reference position 17P _{is R i3.} As shown in FIG. 16, in the first magnetic sensor 16, the second magnetic sensor 18, and the fifth magnetic sensor 17, the detection reference position 16P, the detection reference position 17P, and the detection reference position 18P are located on the first circle C1. . Therefore, the radius R _i1 , the radius R _i2 and the radius R _i3 are the size of the radius R.

In the arrangement of the first magnetic sensor 16 and the fifth magnetic sensor 17, an angle formed by a line connecting the reference rotation axis Ax0 and the detection reference position 16P and a line connecting the reference rotation axis Ax0 and the detection reference position 17P Is the angle φ ₁ '. The angle φ ₁ ′ is an angle different from the angle φ ₁ .

In the second embodiment, the abnormality detection unit 106 illustrated in FIG. 15 is connected to the first magnetic sensor 16, the second magnetic sensor 18, and the fifth magnetic sensor 17. The fifth magnetic sensor 17 outputs a signal of the fifth angle θ _ie3 to the angle correction unit 104 and the abnormality detection unit 106. The fifth angle θ _ie3 is an electrical angle. The fifth magnetic sensor 17 also outputs a signal of the detected magnetic flux density B _im3 to the angle correction unit 104. Based on the number m of magnetic poles and the fifth angle θ _ie3 , the angle correction unit 104 calculates a second angle θ _i3 of the mechanical angle. The electrical angle may be converted to a mechanical angle in the second magnetic sensor 18, and the second angle _θi3 of the mechanical angle may be output to the angle correction unit 104.

The abnormality detection unit 106 detects which one of the first magnetic sensor 16, the second magnetic sensor 18, and the fifth magnetic sensor 17 is abnormal. Specifically, the abnormality detection unit 106 outputs a first electric angle θ _ie1 output by the first magnetic sensor 16, a second electric angle θ _ie2 output by the second magnetic sensor 18, and an output of the fifth magnetic sensor 17. The difference value of the electrical angle may be calculated from the fifth electrical angle θ _ie3 . Then, it is configured to detect which magnetic sensor is abnormal by determining whether the difference value exceeds a predetermined threshold value.

For example, when no abnormality is detected in the first magnetic sensor 16, the second magnetic sensor 18, and the fifth magnetic sensor 17 by the abnormality detection unit 106, the angle correction unit 104 shown in FIG. By solving the simultaneous equations of Equation (19), Equation (20), Equation (23), and Equation (24), the first correction angle θ _is obtained by Equation (27) or Equation (28) _is calculated. The first reference angle θ ₁ , the second reference angle θ ₂ , the constant K _i , the radius R _i1 , the radius R _{i2, the} magnetic flux density B _io1, and the magnetic flux density B _io2 are stored in the storage unit 102 in advance.

When an abnormality is detected in the second magnetic sensor 18 by the abnormality detection unit 106, the angle correction unit 104 detects an abnormality in the output of the first magnetic sensor 16 in which the abnormality is not detected by the abnormality detection unit 106 and the abnormality detection unit 106. The first correction angle θ _is is calculated on the basis of the output of the fifth magnetic sensor 17 in which the value of d is not detected. In the case where the input shaft 82a or the first multipole magnet 12 rotates without error on the reference rotation axis Ax0, the fifth reference distance g3 is separated between the fifth magnetic sensor 17 and the first multipole magnet 12 There is. In this case, the fifth magnetic sensor 17 detects the magnetic flux density B _io3 . The second reference distance amount g3 and the magnetic flux density B _io3 have a relationship of the following formula (43).

  The distance displacement Δg2 between the fifth magnetic sensor 17 and the first multipole magnet 12 can be obtained by equation (44).

The second reference angle θ ₂ ′ is, as shown in FIG. 16, an angle obtained by adding the first reference angle θ ₁ and the angle φ ₁ ′. The first reference angle θ ₁ , the second reference angle θ ₂ ′, the constant K _i , the radius R _i1 , the radius R _i2 , the radius R _i3 and the magnetic flux density B _io3 are stored in the storage unit 102 in advance.

Δg2 determined in the above formula (44), the displacement _{X i,} the angle _{Y i,} and using the angle theta ₂ ', can be represented by the following formula (45).

If information of the magnetic flux density B _im1 and information of the magnetic flux density B _im3 can be obtained from the equations (19) and (44), Δg1 is given to the equation (23), and Δg2 is given to the equation (45), The variables α and β can be determined. When the variable α and the variable β are given to the above equation (25), the angle Y _i can be obtained. When the variable α and the variable β are given to the above equation (26), the displacement X _i can be obtained.

Angle correction unit 104, the following equation (46) gives the displacements _{X i} and the angle _{Y i} based on the equation (25) and the formula (26), calculates a first correction angle theta _IS. As a result, the angle correction unit 104 is configured such that the error due to the first displacement Xi relative to the reference axis of rotation Ax0 of the input shaft 82a or the first multipole magnet 12 is corrected. 1 Correction angle θ _is can be calculated.

  According to this, it is possible to make the magnetic sensor of the rotation angle sensor 10 redundant. As a result, even when the second magnetic sensor 18 fails, the first angle detection unit 100 can continue its function.

As shown in FIG. 17, the rotation angle sensor 20 of Embodiment 2 includes a third magnetic sensor 26, a fourth magnetic sensor 28, and a sixth magnetic sensor 27. Radius from the reference rotation axis Ax0 to detect the reference position 26P _{is R o1.} Radius from the reference rotation axis Ax0 to detect the reference position 28P _{is R o2.} Radius from the reference rotation axis Ax0 to detect the reference position 27P _{is R o3.} As shown in FIG. 17, in the third magnetic sensor 26, the fourth magnetic sensor 28, and the sixth magnetic sensor 27, the detection reference position 26P, the detection reference position 27P, and the detection reference position 28P are located on the second circle C2. . Therefore, the radius R _o1 , the radius R _o2 and the radius R _o3 are the size of the radius R. The straight line L00 shown in FIG. 17 is a straight line drawn from the reference rotation axis Ax0 in the reference direction of the rotation of the second multipole magnet 22.

A line segment connecting the reference rotation axis Ax0 a detection reference position 26P, angle made by the line segment connecting the reference rotation axis Ax0 a detection reference position 28P has a angle phi _2. An angle formed by a line segment connecting the reference rotation axis Ax0 and the detection reference position 26P and a line segment connecting the reference rotation axis Ax0 and the detection reference position 27P is an angle φ ₂ '. The angle φ ₂ ′ is an angle different from the angle φ ₂ .

In the second embodiment, the abnormality detection unit 206 shown in FIG. 15 is connected to the third magnetic sensor 26, the fourth magnetic sensor 28, and the sixth magnetic sensor 27. The sixth magnetic sensor 27 outputs a signal of the fourth angle θ _oe3 to the angle correction unit 204 and the abnormality detection unit 206. The fourth angle θ _oe3 is an electrical angle. Further, the sixth magnetic sensor 27 outputs a signal of the detected magnetic flux density B _{om 3} to the angle correction unit 204.

The abnormality detection unit 206 detects which of the third magnetic sensor 26, the fourth magnetic sensor 28, and the sixth magnetic sensor 27 is abnormal. Specifically, the abnormality detection unit 206 outputs a third electric angle θ _oe1 output by the third magnetic sensor 26, a fourth electric angle θ _oe2 output by the fourth magnetic sensor 28, and a third electric angle output by the sixth magnetic sensor 27. The difference value of the electrical angle may be calculated from 6 electrical angles θ _oe3 . Then, it is configured to detect which magnetic sensor is abnormal by determining whether the difference value exceeds a predetermined threshold value.

For example, when no abnormality is detected in the third magnetic sensor 26, the fourth magnetic sensor 28, and the sixth magnetic sensor 27 by the abnormality detection unit 206, the angle correction unit 204 illustrated in FIG. The second correction angle θ _os calculated by equation (41) or equation (42) is calculated by solving the simultaneous equations of equation (40) from equation (33), equation (34), and equation (37) . The third reference angle θ ₃ , the fourth reference angle θ ₄ , the constant K _o , the radius R _o1 , the radius R _{o2, the} magnetic flux density B _{io 11} and the magnetic flux density B _{io 12} are stored in the storage unit 102 in advance. Although not shown, instead of the first displacement X _i shown in FIG. 11, relative the second displacement with respect to the reference rotation axis Ax0 is as X _o, in place of the angle Y _i, the second displacement X _An angle formed by the direction of _o and a straight line drawn from the reference rotation axis Ax0 to the rotation center of the second multipole magnet 22 is taken as Yo.

When an abnormality is detected in the fourth magnetic sensor 28 by the abnormality detection unit 206, the angle correction unit 204 detects an abnormality in the output of the third magnetic sensor 26 in which the abnormality is not detected by the abnormality detection unit 206 and the abnormality by the abnormality detection unit 206. The second correction angle θ _os is calculated based on the output of the sixth magnetic sensor 27 in which the second magnetic sensor 27 is not detected. When the output shaft 82b or the second multipole magnet 22 rotates without error on the reference rotation axis Ax0, the distance amount gom13 between the sixth magnetic sensor 27 and the second multipole magnet 22 is the second reference distance amount Only g13 is away. In this case, the sixth magnetic sensor 27 detects the magnetic flux density B _{io 13} . The second reference distance amount g13 and the magnetic flux density B _io13 have a relationship of the following formula (47).

  The distance displacement Δg12 between the sixth magnetic sensor 27 and the second multipole magnet 22 can be obtained by equation (48).

The fourth reference angle θ ₄ ′ is, as shown in FIG. 17, an angle obtained by adding the third reference angle θ ₃ and the angle φ ₂ ′. The fourth reference angle θ ₃ , the third reference angle θ ₄ ′, the constant K _i , the radius R _o1 , the radius R _o2 , the radius R _{i 011} and the magnetic flux density B _{io 13} are stored in the storage unit 102 in advance.

Δg12 determined in the above equation (48) can be expressed by the following equation (49) using the displacement X _o , the angle Y _o , and the angle θ ₄ ′.

If information of the magnetic flux density B _om1 and information of the magnetic flux density B _om3 can be obtained from the equations (33) and (48), Δg11 is given to the equation (37), and Δg12 is given to the equation (49). The variable γ and the variable δ can be determined. When the variable γ and the variable δ are given to the above equation (39), the angle _Yo can be obtained. When the variable γ and the variable δ are given to the above equation (40), the displacement X _o can be obtained.

The angle correction unit 204 gives the displacement X _o and the angle Y _o based on the equation (39) and the equation (40) to the following equation (50) to calculate a second correction angle θ _os . As a result, the angle correction unit 204 detects the error due to the second displacement X _o relative to the reference rotational axis Ax 0 of the output shaft 82 b or the second multipole magnet 22 of the second multipole magnet 22. The second correction angle θ _os can be calculated.

  According to this, it is possible to make the magnetic sensor of the rotation angle sensor 20 redundant. As a result, the second angle detection unit 200 can continue its function even when the fourth magnetic sensor 28 breaks down. Further, in the rotation angle sensor 20, even when one of the third magnetic sensor 26, the fourth magnetic sensor 28, and the sixth magnetic sensor 27 fails, the electric power steering apparatus 80 assists the driver's steering. Can.

(Modification 1 of Embodiment 2)
FIG. 18 is a plan view schematically showing a rotation angle sensor that outputs a rotation angle of an input shaft according to a first modification of the second embodiment. In the rotation angle sensor 10 according to the first modification of the second embodiment, the positions of the first magnetic sensor 16, the second magnetic sensor 18, and the fifth magnetic sensor 17 with respect to the reference rotation axis Ax0 are different from those in the second embodiment described above. . In addition, the same code | symbol is attached | subjected to the same component as what was demonstrated in Embodiment 2 mentioned above, and the overlapping description is abbreviate | omitted.

As shown in FIG. 18, in the first magnetic sensor 16, the second magnetic sensor 18, and the fifth magnetic sensor 17, the detection reference position 16P, the detection reference position 17P, and the detection reference positions 18P are equally spaced on a straight line PL1. As such, it is disposed on the substrate 14. The distance W1 is between the detection reference position 16P and the detection reference position 17P, and the distance W1 is between the detection reference position 17P and the detection reference position 18P. Radius from the reference rotation axis Ax0 to detect the reference position 16P _{is R i1.} Radius from the reference rotation axis Ax0 to detect the reference position 18P _{is R i2.} Radius from the reference rotation axis Ax0 to detect the reference position 17P _{is R i3.}

In the rotation angle sensor 10 shown in FIG. 18, the detection reference position 16P and the detection reference position 18P are in line symmetry with respect to a line connecting the reference rotation axis Ax0 and the detection reference position 17P. The angle formed by the straight line PL1 and the line connecting the reference rotation axis Ax0 and the detection reference position 17P is a right angle. Therefore, the radius _Ri1 and the radius _Ri2 have the same size, and the radius _Ri1 and the radius _Ri3 have different sizes.

  FIG. 19 is a plan view schematically showing a rotation angle sensor when an input shaft of a torque sensor according to a first modification of the second embodiment is displaced. The rotation axis Ax1 shown in FIG. 19 is, for example, a rotation axis of the input shaft 82a when the position of the input shaft 82a is displaced by the vibration of the vehicle 101 or the like.

And cause the first displacement X _i, if the abnormality in the second magnetic sensor 18 is detected by the abnormality detection unit 106, an angle correcting unit 104, the first magnetic sensor 16 no abnormality is detected by the abnormality detecting unit 106 The first correction angle θ _is is calculated based on the output of the second magnetic sensor 17 and the output of the fifth magnetic sensor 17 for which the abnormality is not detected by the abnormality detection unit 106. Here, in the storage unit 102, a first reference angle θ ₁ , a second reference angle θ ₂ , a second reference angle θ ₂ ′, a radius _Ri1 , a radius _Ri2 , and a radius _Ri3 are stored in advance.

FIG. 20 is a plan view schematically showing a rotation angle sensor that outputs the rotation angle of the output shaft according to the first modification of the second embodiment. FIG. 21 is a plan view schematically showing a rotation angle sensor when an output shaft of a torque sensor according to a first modification of the second embodiment is displaced. As shown in FIG. 20, the rotation angle sensor 20 of the first modification of the second embodiment includes a third magnetic sensor 26, a fourth magnetic sensor 28, and a sixth magnetic sensor 27. As shown in FIG. 20, in the third magnetic sensor 26, the fourth magnetic sensor 28, and the sixth magnetic sensor 27, the detection reference position 26P, the detection reference position 27P, and the detection reference positions 28P are equally spaced at a straight line PL2. Are disposed on the substrate 24. The distance W1 is between the detection reference position 26P and the detection reference position 27P, and the distance W1 is between the detection reference position 27P and the detection reference position 28P. Radius from the reference rotation axis Ax0 to detect the reference position 26P _{is R o1.} Radius from the reference rotation axis Ax0 to detect the reference position 28P _{is R o2.} Radius from the reference rotation axis Ax0 to detect the reference position 27P _{is R o3.} The radius R _o1 and the radius R _o2 have the same size, and the radius R _o1 and the radius R _o3 have different sizes. The rotation axis Ax1 shown in FIG. 21 is, for example, the rotation axis of the output shaft 82b when the position of the output shaft 82b is displaced due to the vibration of the vehicle 101 or the like. As shown in FIG. 21, the second displacement relative to the reference rotation axis Ax0 is X _o, and instead of the angle Y _i , the direction of the second displacement X _o and the second rotation from the reference rotation axis A x 0 An angle formed by a straight line drawn to the rotation center of the pole magnet 22 is defined as _Yo .

When the second displacement X _o occurs and the abnormality is detected in the fourth magnetic sensor 28 by the abnormality detection unit 206, the angle correction unit 204 detects the third magnetic sensor 26 in which the abnormality is not detected by the abnormality detection unit 206. The second correction angle θ _os is calculated based on the output of the second magnetic sensor 27 and the output of the sixth magnetic sensor 27 for which the abnormality is not detected by the abnormality detection unit 206. Here, in the storage unit 102, a third reference angle θ ₃ , a fourth reference angle θ ₄ , a fourth reference angle θ ₄ ′, a radius R _o1 , a radius R _o2 , and a radius R _o3 are stored in advance.

By this structure, although radius _Ri1 differs from radius _Ri3 , the rotation angle sensor 10 of the modification 1 of Embodiment 2 can calculate 1st correction angle (theta) _is . Similarly, the radius _{R o1} is different from the radius _{R o3,} the rotation angle sensor 20 of the first modification of the second embodiment, it is possible to calculate the second correction angle theta _os.

  The first magnetic sensor 16, the second magnetic sensor 18, and the fifth magnetic sensor 17 are arranged at equal intervals on the straight line PL1 when viewed in the axial direction of the input shaft 82a. Thereby, the degree of freedom of the shape of the substrate 14 is improved. For example, as in the second embodiment, the first magnetic sensor 16, the second magnetic sensor 18, and the fifth magnetic sensor 17 do not have to be equidistant from the reference rotation axis Ax0. There is no need to make a notch. By making the substrate 14 rectangular, the manufacturing efficiency of the substrate 14 is improved. Further, it is only necessary to define the angle formed by the reference rotation axis Ax0, the position of the detection reference position 16P of the first magnetic sensor 16 and the straight line PL1, and the line connecting the reference rotation axis Ax0 and the detection reference position 16P. The assembling accuracy of the rotation angle sensor 10 with respect to the pole magnet 12 is improved.

  The third magnetic sensor 26, the fourth magnetic sensor 28, and the sixth magnetic sensor 27 are equally spaced on the straight line PL2 when viewed in the axial direction of the output shaft 82b. Thereby, the degree of freedom of the shape of the substrate 24 is improved. For example, as in the second embodiment, since the third magnetic sensor 26, the fourth magnetic sensor 28, and the sixth magnetic sensor 27 do not have to be equidistant from the reference rotation axis Ax0, the curved cutting on the substrate 24 is performed. There is no need to make a notch. By making the substrate 24 rectangular, the manufacturing efficiency of the substrate 24 is improved. In addition, the second multiple is only defined by defining the angle between the position of the reference rotational axis Ax0 and the position of the detection reference position 26P of the third magnetic sensor 26 and the straight line PL2, and the line connecting the reference rotational axis Ax0 and the detection reference position 26P. The assembling accuracy of the rotation angle sensor 20 with respect to the pole magnet 22 is improved.

(Modification 2 of Embodiment 2)
FIG. 22 is a plan view schematically showing a rotation angle sensor according to a second modification of the second embodiment. As shown in FIG. 22, the angle formed by the straight line PL1 and the line connecting the reference rotation axis Ax0 and the detection reference position 17P may not be a right angle. Further, the rotation angle sensor 20 can have the same structure as that of the rotation angle sensor 10.

Although the radius R _i1 is different from the radius R _i2 due to this structure, the rotation angle sensor 10 of the second modification of the second embodiment solves the simultaneous equations of equations (13), (14), and (15) The first correction angle θ _is can be calculated by Similarly, although the radius R _o1 is different from the radius R _o2 , the rotation angle sensor 20 of the second variation of the second embodiment can be obtained by solving the simultaneous equations of equations (17), (18), and (19) The second correction angle θ _os can be calculated.

(Modification 3 of Embodiment 2)
FIG. 23 is a plan view schematically showing a rotation angle sensor according to a third modification of the second embodiment.
As shown in FIG. 23, the first magnetic sensor 16, the second magnetic sensor 18, and the fifth magnetic sensor 17 are arranged on the straight line PL1 when viewed in the axial direction of the input shaft 82a. The distance between the detection reference position 16P and the detection reference position 17P is a distance W1, and the distance between the detection reference position 17P and the detection reference position 18P is a distance W2. The distance W2 is larger than the distance W1. Therefore, the distance between the first magnetic sensor 16 and the second magnetic sensor 18 is different from the distance between the second magnetic sensor 18 and the fifth magnetic sensor 17. According to this structure, the radius _Ri1 , the radius _Ri2, and the radius _Ri3 have different sizes. Further, the rotation angle sensor 20 can have the same structure as that of the rotation angle sensor 10.

As described above, although the radius R _i1 is different from the radius R _i2 , the rotation angle sensor 10 according to the third modification of the second embodiment is a system of equations (13), (14), and (15). The first correction angle θ _is can be calculated by solving. Similarly, although the radius R _o1 is different from the radius R _o2 , the rotation angle sensor 20 of the third modification of the second embodiment can be obtained by solving the simultaneous equations of equations (17), (18), and (19). The second correction angle θ _os can be calculated.

(Embodiment 3)
FIG. 24 is a schematic view showing a functional block of a torque sensor according to a third embodiment. FIG. 25 is a flowchart showing a procedure of calculating a steering torque by the torque sensor according to the third embodiment. FIG. 26 is an explanatory diagram for explaining a first correlation value according to the distance of the first magnetic sensor according to the third embodiment. FIG. 27 is an explanatory diagram for describing a second correlation value according to the distance of the second magnetic sensor according to the third embodiment. FIG. 28 is an explanatory view for explaining output characteristics of the first magnetic sensor or the second magnetic sensor according to the third embodiment. The same components as those described in the first embodiment and the third embodiment described above will be assigned the same reference numerals and overlapping descriptions will be omitted.

As shown in FIG. 24, the first magnetic sensor 16, the second magnetic sensor 18, the third magnetic sensor 26, and the fourth magnetic sensor 28 according to the third embodiment have a first distance correlation value P _im1 and a second distance correlation. A value P _im2 , a third distance correlation value P _om1 , and a fourth distance correlation value P _om2 are output.

As shown in FIG. 25, the angle correction unit 104 _acquires a first angle θ _ie1 , a second angle θ _ie2 , a first distance correlation value P _im1 , and a second distance correlation value P _im2 (step ST111).

Here, as shown in FIG. 26, a sin voltage wave K ₁ sinθ _{ie 1} and a cos voltage wave K _{2 cosθ ie} 1 are detected inside the first magnetic sensor 16. and sin voltage wave _K 1 sin [theta _ie1, on the basis of the cos voltage wave _K 2 cos [theta] _ie1, the first magnetic sensor 16, electrical angle of the first angle theta _ie1 can output. Further, as shown in FIG. 27, the sin voltage wave K ₁ sin θ _{ie 2} and the cos voltage wave K ₂ cos θ _ie 2 are detected in the second magnetic sensor 18. and sin voltage wave _K 1 sin [theta _ie2, on the basis of the cos voltage wave _K 2 cos [theta] _ie2, the second magnetic sensor 18, electrical angle of the second angle theta _ie2 can output. In the third embodiment, the first magnetic sensor 16 and the second magnetic sensor 18 are Hall elements. Therefore, as shown in FIG. 28, the first magnetic sensor 16 and the second magnetic sensor 18 are used in the proportional area Q before reaching the saturation point C where the rate of change saturates against the change in magnetic flux density. Then, the Hall output voltage and the magnetic flux density are in a proportional relationship.

First distance correlation value _{P im1} is a sin voltage wave _K 1 sin [theta _ie1, by defining the intensity of the voltage amplitude by a cos voltage wave _K 2 cos [theta] _ie1, can be represented by the following formula (51). The constant K ₁ is a predetermined constant other than zero. Further, the constant K ₂ is a predetermined constant other than zero. The constant K ₁ may or may not be the same as the constant K ₂ .

Similarly, the second distance correlation value P _im2 can be expressed by the following equation (52) when it is defined as the intensity of voltage amplitude by the sin voltage wave K ₁ sin θ _{ie 2} and the cos voltage wave K ₂ cos θ _{ie 2} .

As shown in FIG. 5, in the case where the input shaft 82a or the first multipole magnet 12 rotates without error on the reference rotation axis Ax0, the first magnetic sensor 16 and the first multipole magnet 12 are not 1 Reference distance g1 apart. _sinθio1 and _cosθio1 are functions of the electrical angle detected by the first magnetic sensor 16 when the distance amount gim1 between the first magnetic sensor 16 and the first multipole magnet 12 is the first reference distance amount g1. is there. The first distance correlation value _{P im1} this case, if the first distance correlation value _{P io1,} the first distance correlation value _{P io1} are in a relationship of the following equation (53).

Similarly, in the case where the input shaft 82a or the first multipole magnet 12 rotates with no error on the reference rotation axis Ax0, a second reference distance between the second magnetic sensor 18 and the first multipole magnet 12 is obtained. g2 apart. sin [theta _io2 and cos [theta] _io2 is, when the distance amount gim2 between the second magnetic sensor 18 and the first multi-pole magnet 12 of the second reference distance amount g2, a function of the electrical angle second magnetic sensor 18 detects is there. The second distance correlation value _{P im2} this case, when the second distance correlation value _{P io2,} second distance correlation value _{P io2} are in a relationship of the following equation (54).

The first distance correlation value P _io1 is in inverse proportion to the square of the first reference distance amount g1 and therefore has a relationship of the following equation (55). The constant K _i is a predetermined constant other than zero.

Similarly, the second distance correlation value _Pio2 and the second reference distance amount g2 have a relationship of the following equation (56).

  The formula (55) can be set as the following formula (57).

  The above equation (56) can be made to be the following equation (58).

As shown in FIG. 9, when the rotation axis of the input shaft 82a or the first multipole magnet 12 is displaced from the reference rotation axis Ax0 to the rotation axis Ax1, the first distance correlation value P _io1 detected by the first magnetic sensor 16 Changes to the first distance correlation value P _im1 . Thus, the distance amount gim1 is expressed by the following equation (59).

As shown in FIG. 9, when the rotation axis of the input shaft 82a or the first multipole magnet 12 is displaced from the reference rotation axis Ax0 to the rotation axis Ax1, in the second magnetic sensor 18, the second distance correlation value _Pio2 2 Change to distance correlation value P _im2 Thus, the distance amount gim2 is expressed by the following equation (60).

  The distance displacement Δg1 between the first magnetic sensor 16 and the first multipole magnet 12 can be determined by the equation (61) based on the equations (57) and (59).

  The distance displacement Δg2 between the second magnetic sensor 18 and the first multipole magnet 12 can be obtained by the equation (62) based on the equations (58) and (60).

Here, a displacement X _i described above, at an angle Y _i, define variables α and the variable β by the formula (21) and the formula (22).

The above-mentioned Δg1 can be expressed by the above equation (23) using the displacement X _i , the angle Y _i , and the angle θ ₁ .

Similarly, the above-mentioned Δg ₂ can be expressed by the above equation (24) using the displacement X _i , the angle Y _i , and the angle θ ₂ .

If information of the first distance correlation value P _im1 and information of the second distance correlation value P _im2 can be acquired from the equations (61) and (62), Δg1 is given to the equation (23), and the equation (24) is obtained. ) Can be given to obtain the variable α and the variable β. When the variable α and the variable β are given to the above equation (25), the angle Y _i can be obtained.

Then, given a variable α and the variable β in equation (26), the displacement X _i is obtained.

Angle correction unit 104, the above equation (9) and the following expression based on equation (11) (27) gives the displacements _{X i} and the angle _{Y i} obtained, to calculate a first correction angle theta _IS. Alternatively, the angle corrector 104, the above equation (10) and the following expression based on equation (12) (28) gives the displacements _{X i} and the angle _{Y i} obtained, calculates a first correction angle theta _IS Do. As a result, as shown in FIG. 25, the angle correction unit 104 corrects an error due to the first displacement Xi relative to the reference axis of rotation Ax0 of the input shaft 82a or the first multipole magnet 12. The first correction angle θ _is of the single multipole magnet 12 can be calculated (step ST112).

In the third embodiment, the first distance correlation value P _im1 is determined based on the electrical angle detected by the first magnetic sensor 16, and the distance amount gim 1 between the first magnetic sensor 16 and the first multipolar magnet 12. Is inversely proportional to Further, the second distance correlation value P _im2 is obtained based on the electrical angle detected by the second magnetic sensor 18 and is inversely proportional to the distance amount gim2 between the second magnetic sensor 18 and the first multipolar magnet 12 .

The angle correction unit 104 calculates a first correction angle θ _is based on the first angle θ _ie1 , the second angle θ _ie2 , the first distance correlation value P _im1 , and the second distance correlation value P _im2 . First correction angle theta _IS is the rotation angle of the first multi-pole magnet 12 or the input shaft 82a of at least one depending on the angle error of the error angle Z ₁ and error angle Z ₂ described above has been corrected. More specifically, the first correction angle θ _is is the distance displacement Δg1 between the first magnetic sensor 16 and the first multipole magnet 12 shown in the above equation (61), and the second magnetic angle shown in the above equation (62) The distance displacement Δg2 between the sensor 18 and the first multipole magnet 12 is calculated so as to be zero.

According to this, calculation is performed based on the electrical angle detected by the first magnetic sensor 16 and the electrical angle detected by the second magnetic sensor 18, and the detection accuracy of the first correction angle θ _is of the first multipole magnet 12 _is calculated. It can be enhanced.

As illustrated in FIG. 25, the angle correction unit 204 illustrated in FIG. 24 _acquires the third angle θ _oe1 , the fourth angle θ _oe2 , the third distance correlation value P _om1 , and the fourth distance correlation value P _om2 (step ST121). Note that the third angle θ _oe1 , the fourth angle θ _oe2 , the third distance correlation value P _om1 , and the fourth distance correlation value P _om2 are the first angle θ _ie1 , the second angle θ _ie2 , and the first distance correlation described above. Because it can be calculated similarly to the first angle θ _ie1 , the second angle θ _ie2 , the first distance correlation value P _im1 , and the second distance correlation value P _im2 , corresponding to the value P _im1 and the second distance correlation value P _im2 . I omit explanation.

Next, the angle correction unit 204 calculates a second correction angle θ _os based on the third angle θ _oe1 , the fourth angle θ _oe2 , the third distance correlation value P _om1 , and the fourth distance correlation value P _om2. (Step ST122). The method by which the angle correction unit 204 calculates the second correction angle θ _os is the same as the method by which the angle correction unit 104 calculates the first correction angle θ _is , so detailed description will be omitted. The subsequent processes are also the same as in the first embodiment, and thus detailed description will be omitted.

  In the third embodiment, the first magnetic sensor 16, the second magnetic sensor 18, the third magnetic sensor 26 or the fourth magnetic sensor 28 may be any sensor that can detect a change in the direction of the magnetic flux. The first magnetic sensor 16, the second magnetic sensor 18, the third magnetic sensor 26, and the fourth magnetic sensor 28 may be, for example, spin valve sensors. A spin valve sensor detects a change in the direction of magnetic flux with an element in which a nonmagnetic layer is sandwiched between a ferromagnetic pinned layer in which the direction of magnetization is fixed by an antiferromagnetic layer or the like and a ferromagnetic free layer. It is a possible sensor. The spin valve sensor includes a GMR (Giant Magneto Resistance) sensor and a TMR (Tunnel Magneto Resistance) sensor.

  The first magnetic sensor 16, the second magnetic sensor 18, the third magnetic sensor 26, or the fourth magnetic sensor 28 may be a linear Hall IC capable of detecting the direction of the magnetic flux. A linear Hall IC capable of detecting the direction of magnetic flux includes, for example, a first Hall element and a second Hall element capable of detecting a magnetic flux in a first direction perpendicular to the mounting surface of the linear Hall IC, and a soft magnetic material Prepare. And a soft-magnetic body bends the magnetic flux which penetrates the position where linear Hall IC is arranged. Specifically, the soft magnetic body causes the magnetic flux in the second direction to converge in the first direction so that the magnetic flux in the second direction orthogonal to the first direction of the magnetic flux penetrates the first Hall element. . According to this, the Hall voltage of the first Hall element is proportional to the magnetic flux density of the magnetic flux in the second direction. Furthermore, the soft magnetic body causes the magnetic flux in the third direction to converge in the first direction such that the magnetic flux in the third direction orthogonal to the first direction and the second direction penetrates the second Hall element. Thus, the Hall voltage of the second Hall element is proportional to the magnetic flux density of the magnetic flux in the third direction. With such a configuration, the linear Hall IC detects the direction of the magnetic flux passing through the position where the linear Hall IC is disposed, based on the ratio of the Hall voltage outputted by each of the first Hall element and the second Hall element. be able to.

(Modification of Embodiment 3)
FIG. 29 is an explanatory diagram for describing a first magnetic sensor according to a modification of the third embodiment. FIG. 30 is an explanatory view for explaining output characteristics of the first magnetic sensor or the second magnetic sensor according to the modification of the third embodiment. The same components as those described in the first embodiment, the second embodiment, and the third embodiment described above will be assigned the same reference numerals and overlapping descriptions will be omitted.

  The first magnetic sensor 16, the second magnetic sensor 18, the third magnetic sensor 26 or the fourth magnetic sensor 28 according to the modification of the third embodiment is an anisotropic magnetoresistive (AMR) sensor (hereinafter referred to as “AMR”). It is called an AMR sensor. The first magnetic sensor 16, the second magnetic sensor 18, the third magnetic sensor 26, and the fourth magnetic sensor 28 can detect a change in the direction of the magnetic flux. Hereinafter, although the first magnetic sensor 16 will be described, the second magnetic sensor 18, the third magnetic sensor 26 or the fourth magnetic sensor 28 is the same as the first magnetic sensor 16, and thus the detailed description will be omitted.

As shown in FIG. 29, the first magnetic sensor 16 is disposed such that the direction in which current flows in the ferromagnetic material intersects the reference magnetic field direction FH. As shown in FIG. 6, when the first multipole magnet 12 rotates, the direction of the magnetic line of force 12 m changes with respect to the detection reference position 16P of the first magnetic sensor 16. Therefore, when the first multipole magnet 12 rotates, the direction of the magnetic field changes, and the rate of change in resistance ΔR shown in FIG. 30 changes according to the angle φH with the direction in which the current flows in the ferromagnetic material. Therefore, the first magnetic sensor 16 has an internal circuit set by the Wheatstone bridge circuit or the like so that it operates in the regions Q1 and Q2 in which the rate of change in magnetoresistance ΔR linearly changes with respect to the magnetic field strength. . Thereby, even if the first magnetic sensor 16, the second magnetic sensor 18, the third magnetic sensor 26 or the fourth magnetic sensor 28 is an AMR sensor, the first distance correlation value P _im1 , the second distance correlation value P _im2 , The third distance correlation value P _om1 , and the second distance correlation value P _om2 can be output as a function of the voltage amplitude. Also in the modification of Embodiment 3, the same operation effect as Embodiment 3 can be produced.

(Embodiment 4)
FIG. 31 is a schematic view showing a functional block of a torque sensor according to a fourth embodiment. FIG. 32 is a flowchart showing a procedure of calculating a steering torque by the torque sensor according to the fourth embodiment. FIG. 33 is an explanatory diagram for explaining a first correlation value according to the distance of the first magnetic sensor according to the fourth embodiment. The same components as those described in the first embodiment, the second embodiment, and the third embodiment described above will be assigned the same reference numerals and overlapping descriptions will be omitted.

As shown in FIG. 31, the first magnetic sensor 16, the second magnetic sensor 18, the third magnetic sensor 26, and the fourth magnetic sensor 28 according to the fourth embodiment have a first distance correlation value G _pim1 and a second distance correlation. A value G _pim2 , a third distance correlation value G _pom1 , and a fourth distance correlation value G _pom2 are output.

As shown in FIG. 32, the angle correction unit 104 _acquires a first angle θ _ie1 , a second angle θ _ie2 , a first distance correlation value G _pim1 , and a second distance correlation value G _pim2 (step ST2111).

Here, as shown in FIG. 33, the magnetic flux density is inversely proportional to the square of the distance amount. In FIG. 33, there is a region Q3 in which the first distance correlation value G _pim1 or the second distance correlation value G _pim2 that is a function of the magnetic flux density can be regarded as proportional to the amount of distance. In the fourth embodiment, the first magnetic sensor 16 and the second magnetic sensor 18 are Hall elements.

The first distance correlation value G _pim1 can be expressed by the following equation (63). The constant kj is a predetermined constant. The constant kn is a predetermined constant.

Similarly, the second distance correlation value G _pim2 can be expressed by the following equation (64).

As shown in FIG. 5, in the case where the input shaft 82a or the first multipole magnet 12 rotates without error on the reference rotation axis Ax0, the distance between the first magnetic sensor 16 and the first multipole magnet 12 gim1 is separated by a first reference distance amount g1. The first distance correlation value _{G pim1} this case, if the first distance correlation value _{G PIO1,} first distance correlation value _{G PIO1} are in a relationship of the following equation (65).

Similarly, in the case where the input shaft 82a or the first multipole magnet 12 rotates without error on the reference rotation axis Ax0, the distance amount gim1 between the second magnetic sensor 18 and the first multipole magnet 12 is the second It is separated by the reference distance amount g2. The second distance correlation value _{G pim2} this case, when the second distance correlation value _{G PIO2,} second distance correlation value _{G PIO2} are in a relationship of the following equation (66).

  The distance displacement Δg1 between the first magnetic sensor 16 and the first multipole magnet 12 can be obtained by the equation (67) based on the equations (63) and (65).

  The distance displacement Δg2 between the second magnetic sensor 18 and the first multipole magnet 12 can be obtained by the equation (68) based on the equations (64) and (66).

Here, a displacement X _i described above, at an angle Y _i, define variables α and the variable β by the formula (21) and the formula (22).

The above-mentioned Δg1 can be expressed by the above equation (23) using the displacement X _i , the angle Y _i , and the angle θ ₁ . Then, .DELTA.G1, based on the equation (21) and the formula (22), the variable alpha, the variable beta, and may be expressed using the angle theta _1.

Similarly, the above-mentioned Δg ₂ can be expressed by the above equation (24) using the displacement X _i , the angle Y _i , and the angle θ ₂ . Then, Δg ₂ can also be expressed using the variable α, the variable β, and the angle θ ₂ based on the above equation (21) and the above equation (22).

If information of the first distance correlation value G _pim1 and information of the second distance correlation value G _pim2 can be obtained from the equations (63) and (64), Δg1 is given to the equation (23), and the equation (24) is obtained. ) Can be given to obtain the variable α and the variable β. When the variable α and the variable β are given to the above equation (25), the angle Y _i can be obtained.

Then, given a variable α and the variable β in equation (26), the displacement X _i is obtained.

Angle correction unit 104, the above equation (9) and the following expression based on equation (11) (27) gives the displacements _{X i} and the angle _{Y i} obtained, to calculate a first correction angle theta _IS. Alternatively, the angle corrector 104, the above equation (10) and the following expression based on equation (12) (28) gives the displacements _{X i} and the angle _{Y i} obtained, calculates a first correction angle theta _IS Do. As a result, the angle correction unit 104 is configured such that the error due to the first displacement Xi relative to the reference axis of rotation Ax0 of the input shaft 82a or the first multipole magnet 12 is corrected. 1 correction angle θ _is can be calculated (step ST212).

In the fourth embodiment, the first distance correlation value G _pim1 is determined based on the magnetic flux density detected by the first magnetic sensor 16, and the distance amount gim 1 between the first magnetic sensor 16 and the first multipolar magnet 12. Proportional to Further, the second distance correlation value G _pim2 is obtained based on the magnetic flux density detected by the second magnetic sensor 18 and is proportional to the distance amount gim2 between the second magnetic sensor 18 and the first multipole magnet 12 .

The angle correction unit 104 calculates a first correction angle θ _is based on the first angle θ _ie1 , the second angle θ _ie2 , the first distance correlation value G _pim1 , and the second distance correlation value G _pim2 . First correction angle theta _IS is the rotation angle of the first multi-pole magnet 12 or the input shaft 82a of at least one depending on the angle error of the error angle Z ₁ and error angle Z ₂ described above has been corrected. More specifically, the first correction angle θ _is is the distance displacement Δg1 between the first magnetic sensor 16 and the first multipole magnet 12 shown in the above equation (67), and the second magnetic angle shown in the above equation (68) The distance displacement Δg2 between the sensor 18 and the first multipole magnet 12 is calculated so as to be zero.

According to this, calculation is performed based on the magnetic flux density detected by the first magnetic sensor 16 and the magnetic flux density detected by the second magnetic sensor 18, and the detection accuracy of the first correction angle θ _is of the first multipole magnet 12 _is calculated. It can be enhanced.

As illustrated in FIG. 32, the angle correction unit 204 illustrated in FIG. 31 _acquires the third angle θ _oe1 , the fourth angle θ _oe2 , the third distance correlation value G _pom1 , and the fourth distance correlation value G _pom2 (step ST 221). Note that the third angle θ _oe1 , the fourth angle θ _oe2 , the third distance correlation value G _pom1 , and the fourth distance correlation value G _pom2 are the first angle θ _ie1 , the second angle θ _ie2 , and the first distance correlation described above. It corresponds to the value _{G pim1,} and a second distance correlation value _{G pim2,} first angle theta _ie1, second angle theta _ie2, first distance correlation value _{G pim1,} and can be calculated similarly to the second distance correlation value _{G pim2} I omit explanation.

Next, the angle correction unit 204 calculates a second correction angle θ _os based on the third angle θ _oe1 , the fourth angle θ _oe2 , the third distance correlation value G _pom1 , and the fourth distance correlation value G _pom2. (Step ST222). The method by which the angle correction unit 204 calculates the second correction angle θ _os is the same as the method by which the angle correction unit 104 calculates the first correction angle θ _is , so detailed description will be omitted. The subsequent processes are also the same as in the first embodiment, and thus detailed description will be omitted.

(Modification of Embodiment 4)
FIG. 34 is an explanatory diagram for explaining a first correlation value according to the distance of the first magnetic sensor according to the modification of the fourth embodiment. The same components as those described in the first embodiment, the second embodiment, the third embodiment, and the fourth embodiment described above are denoted by the same reference numerals, and redundant description will be omitted.

As described in the third embodiment, the magnitude of the voltage amplitude shown in FIG. 34 is inversely proportional to the square of the distance amount. In FIG. 34, there is a region Q3 in which the first distance correlation value G _pim1 or the second distance correlation value G _pim2 that is a function of the magnitude of the voltage amplitude can be regarded as proportional to the amount of distance. In the modification of the fourth embodiment, the first magnetic sensor 16 and the second magnetic sensor 18 are Hall elements or AMR sensors.

The first distance correlation value G _{pim1 according} to the modification of the fourth embodiment is _{obtained in the} same manner as the first distance correlation value P _im1 of the third embodiment or the modification of the third embodiment. The second distance correlation value G _{pim2 according to} the modification of the fourth embodiment is obtained in the same manner as the second distance correlation value P _im2 of the third embodiment or the modification of the third embodiment.

If the first distance correlation value G _pim1 and the second distance correlation value G _{pim2 according} to the modification of the fourth embodiment are obtained, processing can be performed in the same manner as the fourth embodiment.

In the modification of the fourth embodiment, the first distance correlation value G _pim1 is determined based on the electrical angle detected by the first magnetic sensor 16, and between the first magnetic sensor 16 and the first multipolar magnet 12. It is proportional to the distance amount gim1. Further, the second distance correlation value G _pim2 is determined based on the electrical angle detected by the second magnetic sensor 18 and is proportional to the distance amount gim2 between the second magnetic sensor 18 and the first multipole magnet 12 .

The angle correction unit 104 calculates a first correction angle θ _is based on the first angle θ _ie1 , the second angle θ _ie2 , the first distance correlation value G _pim1 , and the second distance correlation value G _pim2 . First correction angle theta _IS is the rotation angle of the first multi-pole magnet 12 or the input shaft 82a of at least one depending on the angle error of the error angle Z ₁ and error angle Z ₂ described above has been corrected. More specifically, the first correction angle θ _is is the distance displacement Δg1 between the first magnetic sensor 16 and the first multipole magnet 12 shown in the above equation (67), and the second magnetic angle shown in the above equation (68) The distance displacement Δg2 between the sensor 18 and the first multipole magnet 12 is calculated so as to be zero.

According to this, calculation is performed based on the electrical angle detected by the first magnetic sensor 16 and the electrical angle detected by the second magnetic sensor 18, and the detection accuracy of the first correction angle θ _is of the first multipole magnet 12 _is calculated. It can be enhanced.

Embodiment 5
FIG. 35 is a perspective view schematically showing a torque sensor according to the fifth embodiment. FIG. 36 is a plan view for explaining the positional relationship between the angle magnetic sensor and the magnet according to the fifth embodiment. FIG. 37 is a schematic view showing a functional block of the torque sensor according to the fifth embodiment. As shown in FIGS. 35 to 37, the torque sensor 400a according to the fifth embodiment includes a first gear 30a, a second gear 32a, a magnet 34a, and an angle magnetic sensor 36a. It differs from the above-described torque sensor 400 in that it includes the angle detection unit 300a. In addition, the same code | symbol is attached | subjected to the same component as what was demonstrated in Embodiment 1 mentioned above, and the overlapping description is abbreviate | omitted.

  As shown in FIG. 35, the first gear 30a is attached to the input shaft 82a. The first gear 30a rotates in synchronization with the input shaft 82a. As shown in FIG. 36, the second gear 32a is rotatably fixed around the rotation axis Ax2. The second gear 32a is fixed to, for example, a vehicle body. The second gear 32a is disposed to mesh with the first gear 30a. The second gear 32a rotates in conjunction with the first gear 30a. The gear ratio of the first gear 30a to the second gear 32a is, for example, three. That is, when the first gear 30a makes one rotation, the second gear 32a makes three rotations.

  As shown in FIGS. 35 and 36, the magnet 34a is a cylindrical permanent magnet. The magnet 34a is magnetized in the radial direction of the magnet 34a. The magnet 34a is disposed inside the second gear 32a. The magnet 34a rotates in synchronization with the second gear 32a with the rotation axis Ax2 as a rotation axis. For the magnet 34a, for example, a neodymium magnet, a ferrite magnet, a samarium cobalt magnet or the like is used according to the required magnetic flux density. The magnetization pattern of the magnet 34a may be any pattern that allows the angle magnetic sensor 36a to detect the rotation of the magnet 34a.

As shown in FIG. 37, the relative angle detection unit 300a differs from the relative angle detection unit 300 in that the? _An calculation unit 38a and the first angle detection unit 100a are provided instead of the first angle detection unit 100. As shown in FIGS. 35 and 36, the angle magnetic sensor 36a is disposed on the rotation axis Ax2. The angle magnetic sensor 36a is disposed to face the top surface of the magnet 34a. The angle magnetic sensor 36a is fixed to, for example, a vehicle body. As shown in FIG. 37, the angle the magnetic sensor 36a, every time the magnet 34a is rotated 1, and outputs a cosine wave signal cos [theta] _an, sinusoidal signals sin [theta _an, and one period of one cycle theta _an, calculation unit 38a. The angle magnetic sensor 36a is, for example, a spin valve sensor. A spin valve sensor detects a change in the direction of magnetic flux with an element in which a nonmagnetic layer is sandwiched between a ferromagnetic pinned layer in which the direction of magnetization is fixed by an antiferromagnetic layer or the like and a ferromagnetic free layer. It is a possible sensor. The spin valve sensor includes a GMR (Giant Magneto Resistance) sensor and a TMR (Tunnel Magneto Resistance) sensor. The angle magnetic sensor 36a may be any sensor that can detect the rotation of the magnet 34a. The angle magnetic sensor 36a may be, for example, an AMR sensor or a Hall sensor.

As shown in FIG. 37, the θ _an calculator 38a calculates the angle magnetic sensor detection angle θ _{an according} to the following equation (69) stored in the storage unit 102. The θ _an calculating unit 38 a outputs the calculated angle magnetic sensor detection angle θ _an to the first angle detecting unit 100 a.

The first angle detection unit 100a differs from the first angle detection unit 100 in that it includes an angle correction unit 104a on the input shaft side instead of the angle correction unit 104 on the input shaft side. The angle correction unit 104a is the same as the angle correction unit 104 except that the rotation number of the input shaft 82a is calculated based on the first angle θ _ie1 and the angle magnetic sensor detection angle θ _an .

FIG. 38 is an explanatory view showing a relationship between a first angle and angle magnetic sensor detection angle according to Embodiment 5 and a magnetic pole of a first multipole magnet. The input shaft mechanical angle shown on the horizontal axis of FIG. 38 indicates the mechanical angle (rotation angle) of the input shaft 82a. The electrical angle shown in the upper part of FIG. 38 indicates the first angle θ _ie1 . The electrical angle shown in the lower part of FIG. 38 indicates the angle magnetic sensor detection angle θ _an . In addition. In FIG. 38, the number m of magnetic poles of the first multipole magnet 12 is described as 8 for convenience. With reference to FIG. 38, when the magnetic pole number m of the first multipole magnet 12 is 8, an example of a method of calculating the number of rotations N which is the number of rotations of the input shaft 82a will be described. Since the gear ratio of the first gear 30a to the second gear 32a is 3, the magnet 34a rotates 1080 degrees when the input shaft 82a rotates 360 degrees. The angle magnetic sensor 36a outputs a signal of one cycle when the magnet 34a rotates 360 degrees. Therefore, as shown in FIG. 38, the angle magnetic sensor detection angle θ _an has a cycle of 120 degrees in the mechanical angle of the input shaft 82a. The first angle θ _ie1 outputs a signal of one cycle each time the magnetic pole at the opposing position of the first magnetic sensor 16 changes by one magnetic pole pair. Therefore, as shown in FIG. 38, the first angle θ _ie1 has a cycle of 90 degrees at the mechanical angle of the input shaft 82a. From the above, the angle magnetic sensor detection angle θ _an and the first angle θ _ie1 are mechanical angles of the input shaft 82 a, and the phase (electrical angle) coincides with each other every 360 degrees. That is, the angle magnetic sensor detection angle θ _an and the first angle θ _ie1 coincide in phase each time the input shaft 82 a rotates. When the phases of the angle magnetic sensor detection angle θ _an and the first angle θ _ie1 coincide with each other, the angle correction unit 104 a stores the number of rotations N stored in the storage unit 102 according to the rotation direction of the first multipole magnet 12. Add or subtract 1 to. According to this, even when the input shaft 82a is rotated for more than one rotation, the first angle detection unit 100a can count the number of rotations of the input shaft 82a (multi-rotation detection).

In the torque sensor 400a according to the fifth embodiment, the vernier calculation of the angle magnetic sensor detection angle θ _an and any one of the first angle θ _ie1 and the second angle θ _ie2 is _performed for the first multipole magnet 12. The rotation angle may be calculated. In this case, the second magnetic pole number m and the second gear 30a are appropriately set so that the cycle of the angle magnetic sensor detection angle θ _{an and} the cycle of the first angle θ _{ie1 and} the cycle of the second angle θ _ie2 become different values. The gear ratio of the gear 32a may be selected. The gear ratio of the second gear 32a to the first gear 30a may be different from, for example, a value obtained by dividing 2 by the number of magnetic poles m. According to this, it is possible to make the cycle of the angle magnetic sensor detection angle θ _{an different from} the cycle of the first angle θ _{ie1 and} the cycle of the second angle θ _ie2 . As a result, the rotation angle of the first multipole magnet 12 can be detected by the vernier calculation. Also, the absolute angle of multi-rotation of the first multipole magnet 12 can be calculated by vernier calculation of the angle magnetic sensor detection angle θ _an and any one of the first angle θ _ie1 and the second angle θ _ie2 Good. In order to calculate the absolute angle of multiple rotations, the rotation angle of 360 degrees or less of the input shaft 82a (first multipole magnet 12) or the rotation angle of more than 360 degrees of the input shaft 82a (first multipole magnet 12) is absolute It is to calculate in the corner.

DESCRIPTION OF SYMBOLS 10 Rotation angle sensor 12 1st multipole magnet 16 1st magnetic sensor 16P, 18P, 26P, 28P Detection reference position 18 2nd magnetic sensor 17 5th magnetic sensor 20 rotation angle sensor 22 2nd multipole magnet 26 3rd magnetic sensor 27 Sixth magnetic sensor 28 Fourth magnetic sensor 30a First gear 32a Second gear 34a Magnet 36a Angle magnetic sensor 80 Electric power steering device 82a Input shaft (first shaft)
82b Output shaft (second shaft)
82c Torsion bar 90 ECU
100 First angle detector (first angle detector)
101 Vehicle 102 Storage Unit 104, 104a Angle Correction Unit 106, 206 Abnormality Detection Unit 200 Second Angle Detection Unit (Second Angle Detection Device)
204 Angle correction unit 300, 300a Relative angle detection unit (relative angle detection device)
302 difference calculation unit 400,400a torque sensor 402 torque calculating section _{B io1, B io2} flux density C1 first circle C2 second circle _X i, _{X o} displacement _{Y i, Y io} angle [Delta] [theta] _io relative angle theta _ie1 first angle theta _ie2 second angle θ _is first correction angle θ _oe1 third angle θ _oe 2 fourth angle θ _os second correction angle

Claims (16)

The first shaft,
A first multipole magnet which rotates in conjunction with the rotation of the first shaft and in which different magnetic poles are alternately arranged along the circumferential direction of the first shaft;
A first magnetic sensor disposed on an outer peripheral side of the first multipole magnet;
A second magnetic sensor disposed on an outer peripheral side of the first multipole magnet;
And an angle correction unit,
The first magnetic sensor and the second magnetic sensor are disposed at positions different from each other in the 180 ° symmetrical position with respect to the first multipole magnet, and at circumferentially different positions around the first multipole magnet. ,
The first magnetic sensor can output a first distance correlation value according to a first distance to the first multipole magnet,
The second magnetic sensor can output a second distance correlation value according to a second distance to the first multipole magnet,
The angle correction unit is configured to adjust the first angle detected by the first magnetic sensor according to the rotation of the first multipole magnet, the first distance correlation value, and the second according to the rotation of the first multipole magnet. An angle detection device that calculates a first correction angle of the first multipole magnet based on a second angle detected by a magnetic sensor and the second distance correlation value. The first distance correlation value is a value of the magnetic flux density detected by the first magnetic sensor,
The angle detection device according to claim 1, wherein the second distance correlation value is a value of magnetic flux density detected by the second magnetic sensor. Distance displacement Δg1 between the first magnetic sensor and the first multipole magnet shown in the following formula (1) and distance displacement Δg2 between the second magnetic sensor and the first multipole magnet shown in the following formula (2) The angle detection device according to claim 2, wherein a first correction angle of the first multipole magnet is calculated such that and are 0, respectively.

Here, Bim1 is a value of the magnetic flux density detected by the first magnetic sensor, and
Bio1 is a value of the magnetic flux density detected by the first magnetic sensor when the distance between the first magnetic sensor and the first multipole magnet is a first reference distance amount,
Bim2 is a value of the magnetic flux density detected by the second magnetic sensor,
Bio2 is a value of the magnetic flux density detected by the second magnetic sensor when the distance between the second magnetic sensor and the first multipole magnet is a second reference distance, and Ki is other than 0. Is a predetermined constant of The first distance correlation value is obtained based on the electrical angle detected by the first magnetic sensor, and is inversely proportional to the distance between the first magnetic sensor and the first multipole magnet.
The second distance correlation value is determined based on an electrical angle detected by the second magnetic sensor, and is inversely proportional to a distance amount between the second magnetic sensor and the first multipole magnet. Angle detector as described. Distance displacement Δg1 between the first magnetic sensor and the first multipole magnet shown in the following formula (3) and distance displacement Δg2 between the second magnetic sensor and the first multipole magnet shown in the following formula (4) And the first distance correlation value Pim1 satisfies the following equation (5) and the following equation (7), and the second correction angle of the first multipole magnet is calculated so that The angle detection device according to claim 4, wherein the distance correlation value Pim2 satisfies the following equation (6) and the following equation (8).

Here, sin θie1 and cosθie1 are functions of the electrical angle detected by the first magnetic sensor,
sin θie 2 and cos θie 2 are functions of the electrical angle detected by the second magnetic sensor,
sin θio1 and cos θio1 are functions of the electrical angle detected by the first magnetic sensor when the distance between the first magnetic sensor and the first multipole magnet is a first reference distance,
A first distance correlation value Pio1 is a first distance correlation value Pim1 when the distance between the first magnetic sensor and the first multipole magnet is a first reference distance amount,
sin θio 2 and cos θio 2 are functions of the electrical angle detected by the second magnetic sensor when the distance between the second magnetic sensor and the first multipole magnet is a second reference distance,
A second distance correlation value Pio2 is a second distance correlation value Pim2 when the distance between the second magnetic sensor and the first multipole magnet is a second reference distance amount,
Each of Ki, K1, and K2 is a predetermined constant other than zero. The first distance correlation value is obtained based on the magnetic flux density detected by the first magnetic sensor, and is proportional to the distance between the first magnetic sensor and the first multipole magnet.
The second distance correlation value is determined based on the magnetic flux density detected by the second magnetic sensor, and is proportional to the distance between the second magnetic sensor and the first multipole magnet. Angle detector as described. The first distance correlation value is obtained based on the electrical angle detected by the first magnetic sensor, and is proportional to the distance between the first magnetic sensor and the first multipole magnet.
The second distance correlation value is determined based on the electrical angle detected by the second magnetic sensor, and is proportional to the distance between the second magnetic sensor and the first multipole magnet. Angle detector as described. The pitches of the respective magnetic poles of the first multipole magnet are the same,
A line segment drawn from the rotation reference position which is the reference of the rotation center of the predetermined first shaft or the first multipole magnet to the detection reference position of the first magnetic sensor and the detection reference position of the second magnetic sensor The angle to be formed is an angle obtained by multiplying the mechanical angle of one magnetic pole pair of the first multipolar magnet by an integer multiple,
The anomaly detection unit according to claim 1, further comprising: an anomaly detection unit capable of detecting that at least one of the first magnetic sensor and the second magnetic sensor is abnormal by comparing the first angle and the second angle. The angle detection device according to any one of 7. A first gear that rotates in synchronization with the first multipole magnet;
A second gear engaged with the first gear and rotationally driven by rotation of the first gear;
A magnet which is cylindrical and magnetized in a radial direction of the cylinder and rotates integrally with the second gear;
And an angle magnetic sensor disposed on the rotation axis of the magnet.
The angle magnetic sensor outputs a signal of one cycle according to a magnetic field change of one rotation of the magnet,
The angle detection device according to any one of claims 1 to 8, wherein the product of the gear ratio of the second gear to the first gear and the number of magnetic poles of the first multipole magnet is other than two.   The angle correction unit executes a vernier operation from the signal of the angle magnetic sensor and the first angle, and the rotation angle of the first multipole magnet is 360 degrees or less, or 360 degrees of the first multipole magnet The angle detection device according to claim 9, wherein a rotation angle exceeding is calculated as an absolute angle.   The radius from the reference rotation axis of the first shaft or the first multipole magnet to the detection reference position of the first magnetic sensor is the same as the radius from the reference rotation axis to the detection reference position of the second magnetic sensor The angle detection device according to any one of claims 1 to 10.   The first magnetic sensor and the second magnetic sensor are arranged in a straight line when viewed in the axial direction of the first shaft, and the first magnetic sensor and the second multipole magnet are rotated from a reference rotation axis of the first shaft or the first multipole magnet. The angle detection device according to any one of claims 1 to 10, wherein a radius to the detection reference position is different from a radius from the reference rotation axis to the detection reference position of the second magnetic sensor. A first angle detection device, which is the angle detection device according to any one of claims 1 to 12.
A second multipole magnet that rotates in synchronization with the rotation of the second shaft and the second shaft, and in which different magnetic poles are alternately arranged along the circumferential direction of the second shaft, and the second multipole magnet A third magnetic sensor disposed on the outer circumferential side, and a fourth magnetic sensor disposed on the outer circumferential side of the second multipole magnet,
The third magnetic sensor and the fourth magnetic sensor are arranged at different positions in the circumferential direction around the second multipole magnet, different from the 180 ° symmetrical position sandwiching the second multipole magnet. ,
The third magnetic sensor can output a third distance correlation value according to a third distance to the second multipole magnet,
The fourth magnetic sensor can output a fourth distance correlation value according to a fourth distance to the second multipole magnet,
The angle correction unit is configured to adjust a third angle detected by the third magnetic sensor according to the rotation of the second multipole magnet, the third distance correlation value, and the fourth angle according to the rotation of the second multipole magnet. A second angle detection device that calculates a second correction angle of the second multipole magnet based on a fourth angle detected by a magnetic sensor and the fourth distance correlation value;
A relative angle detection device comprising: a difference calculation unit that calculates a relative rotation angle between the first multipole magnet and the second multipole magnet from the difference between the first correction angle and the second correction angle. A torsion bar,
The relative angle detection device according to claim 13, wherein the relative rotation angle between one end of the torsion bar and the other end of the torsion bar is detected.
A torque calculation unit that calculates a torque applied to the torsion bar based on the relative rotation angle calculated by the relative angle detection device.   An electric power steering apparatus comprising the torque sensor according to claim 14.   A vehicle comprising the electric power steering apparatus according to claim 15.

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