JP2011169716A - Rotation angle detecting device, and power steering device including the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotation angle detecting device which suppresses detection errors when a shaft shifts in the radial direction, and a power steering device having the same. <P>SOLUTION: A rotation angle sensor 50 includes a magnetic member 44 that is disposed integrally in an input shaft 41 and where the N pole and the S pole are magnetized with a predetermined interval in the circumferential direction of the input shaft 41, and an MR sensor 45 that is placed opposite to the magnetic member 44 and detects variation of the magnetic field by the N pole and S pole. A plurality of MR sensors 45 are arranged at different directions in the circumferential direction of the input shaft 41. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a rotation angle detection device that can be applied to rotation angle detection and rotation torque detection, and a power steering device including the rotation angle detection device.

  In general, in a vehicle equipped with a power steering device, in order to detect steering torque by a driver, it rotates with respect to an input shaft on the steering wheel side and an output shaft on the steering gear box side that are connected to each other via a torsion bar. A rotation angle detection device that detects the angle is provided, and the steering torque is obtained from the difference between the two rotation angles, or the relative rotation angle between the input shaft and the output shaft is detected by the rotation angle detection device, and steering is performed from the detected rotation angle. I'm seeking torque.

  In this type of rotation angle detection device, in order to prevent detection errors from occurring even when the detection means is assembled with a target provided on the steering shaft shifted in the axial direction of the shaft, Disc-shaped targets alternately arranged in the circumferential direction are provided integrally with the steering shaft, and a pair of magnetoresistive elements (hereinafter referred to as MR elements) arranged in parallel in the circumferential direction in accordance with the arrangement interval between the N pole and the S pole. (Patent Document 1) proposes an invention in which a detecting means is configured to detect a rotation angle based on a change in output between both MR elements.

JP 2003-114103 A

  However, when an input other than rotational torque is input to the input shaft or an external force applied to the wheels is transmitted to the output shaft, the steering shaft may be displaced in the radial direction. In such a case, since the rotation angle detection device described in the cited document 1 has only one detecting means, the deviation of the steering shaft is detected as the rotation angle, and the actual rotation angle and the detected rotation angle An error will occur between the two.

  The present invention has been made in view of such a background, and an object of the present invention is to provide a rotation angle detection device capable of suppressing detection errors when a shaft is displaced in the radial direction, and a power steering device including the rotation angle detection device. And

  In order to solve the above-mentioned problem, in the rotation angle detector (50), the first invention is provided integrally with the first shaft (input shaft 41) and has a predetermined interval in the circumferential direction of the first shaft (41). And a magnetic member (44) magnetized with N and S poles, and a magnetic detection element (MR sensor 45) disposed opposite to the magnetic member (44) and detecting a change in magnetic field due to the N and S poles. And a plurality of magnetic detection elements (45) are arranged at different positions in the circumferential direction of the first shaft (41).

  According to the present invention, when the first shaft is displaced in the radial direction, it is detected that the rotation angle is generated in a different manner by the plurality of magnetic detection elements. Therefore, the first detection is based on the displacement of the rotation angle detected by these detection elements. The amount corresponding to the amount of deviation of the shaft in the radial direction can be canceled.

  According to a second aspect of the present invention, in the rotation angle detection device (50) according to the first aspect, the plurality of magnetic detection elements (45) are coaxial with the first shaft (41) via the torsion bar (43). The second shaft (output shaft 42) to be connected is provided integrally. According to this invention, even when the axial centers of the first shaft and the second shaft that are coaxially connected to each other are displaced, the amount corresponding to the displacement amount can be canceled from the displacement of the rotation angle.

  According to a third aspect of the present invention, in the rotation angle detection device (50) according to the first or second aspect, the plurality of magnetic detection elements (45) pass through the axial center (41X) of the first shaft (41). It is characterized by being arranged so as to be line symmetric with respect to the line. According to the present invention, a pair of magnetic detection elements that are symmetrical with respect to a line detects a shaft shift in the direction of the reference line as the same absolute value but with different positive and negative rotation amounts. Therefore, it is possible to cancel the amount corresponding to the shift amount in the symmetric line direction from the displacement of the rotation angle only by using the average value of the detected values. Further, according to a fourth aspect of the present invention, in the rotation angle detection device (50) according to the first to third aspects, the plurality of magnetic detection elements (45) pass through the axial center (41X) of the first shaft (41). It is characterized by being arranged so as to be 180 degrees symmetrical with respect to the line. According to the present invention, the shaft misalignment is detected as a rotation angle having the same absolute value and different positive and negative in the pair of magnetic detection elements targeted for 180 degrees. Therefore, the amount corresponding to the amount of deviation can be canceled from the displacement of the rotation angle only by using the average value of the amount detection values.

  According to a fifth invention, in the rotation angle detection device (50) according to any one of the first to fourth inventions, the magnetic detection element (45) includes an MR element (46) or a GMR element. The sixth invention is characterized in that the power steering device (1) includes the rotation angle detection device (50) according to any one of the first to fifth inventions.

  According to the present invention, it is possible to provide a rotation angle detection device capable of suppressing a detection error even when the shaft is displaced in the radial direction, and a power steering device including the rotation angle detection device.

It is a mimetic diagram showing an electric power steering device to which the present invention is applied. It is a functional block diagram which shows schematic structure of the steering control apparatus shown in FIG. It is a perspective view which shows schematic structure of the steering torque sensor shown in FIG. It is explanatory drawing of the detection principle by the rotation angle sensor shown in FIG. It is explanatory drawing of the detection state by the rotation angle sensor shown in FIG. It is explanatory drawing of the detection state by the rotation angle sensor shown in FIG. 3 when the shift | offset | difference arises in the shaft. It is a side view which shows typically the steering torque sensor shown in FIG. It is explanatory drawing of the detection state by the upper and lower torque sensors shown in FIG. It is a side view which shows typically the steering angle sensor rotation angle sensor shown in FIG. It is a schematic diagram of the rotation angle / torque sensor according to another embodiment.

  Embodiments according to the present invention will be described below with reference to the drawings.

  As shown in FIG. 1, an electric power steering apparatus 1 to which the present invention is applied includes a pinion 4 connected to a steering handle 2 via a steering shaft 3, and meshes with the pinion 4 to reciprocate in the vehicle width direction. A rack and pinion mechanism having a rack shaft 5 movably provided, and both ends of the rack shaft 5 are connected to left and right front wheels 7 as steering wheels via tie rods 6, and the steering handle 2 The left and right front wheels 7 are steered according to the rotation operation.

  The electric power steering apparatus 1 is provided with a motor 9 that generates an auxiliary steering force for reducing the steering force applied to the steering handle 2 by the driver. The driving force of the motor 9 is contained in the gear box 11. It is input to the steering shaft 3 through the worm gear mechanism 10 housed together with the pinion 4.

  A steering torque sensor 12 that detects a steering torque acting on the pinion 4 is provided in the gear box 11, and a steering angle sensor 13 that detects the steering angle of the steering handle 2 is provided on the steering shaft 3. . A vehicle speed sensor 14 for detecting the vehicle speed is provided at an appropriate position of the vehicle body. The motor 9 is provided with a resolver 15 that detects a motor rotation angle. Output signals of the steering torque sensor 12, the steering angle sensor 13, the vehicle speed sensor 14, and the resolver 15 are input to a steering control device (EPS-ECU) 21 that comprehensively controls the operation of the electric power steering device 1. The

  The steering control device 21 includes a microcomputer, ROM, RAM, peripheral circuit, input / output interface, various drivers, and the like, and a target current for driving and controlling the motor 9 based on output signals of the sensors 12 to 14. A value It (control value) is determined and input to the drive circuit 22 of the motor 9. The drive circuit 22 includes an FET bridge circuit and the like, and supplies power to the motor 9 based on the target current value It determined by the steering control device 21, thereby controlling the output torque of the motor 9. In addition to this, the steering control device 21 has functions of fail-safe, self-diagnosis, motor output restriction, and external diagnostic communication.

  As shown in FIG. 2, the steering control device 21 includes a base current calculation unit 31, an inertia correction current calculation unit 32, a damper correction current calculation unit 33, an adder 34, and a subtracter 35. . In addition, each part of this steering control device 21 is implement | achieved by running the program stored in memory with CPU.

  The base current calculation unit 31 calculates a base current value Ia that is the basis of the target current value It. Based on the steering torque by the steering torque sensor 12 and the vehicle speed by the vehicle speed sensor 14, the correlation between them is calculated. The base current value Ia is obtained by referring to the map shown.

  The inertia correction current calculation unit 32 compensates for the influence of the inertia of the steering system, and shows a correlation with these based on the time differential value of the steering torque by the steering torque sensor 12 and the vehicle speed by the vehicle speed sensor 14. The inertia correction current value Ib is calculated by referring to the map. The inertia correction current value Ib is added to the base current value Ia by the adder 34, thereby improving the response delay of the steering due to the inertia of the steering system and obtaining a clean steering feeling.

  The damper correction current calculation unit 33 compensates the influence of the viscosity of the steering system, and based on the motor rotation speed obtained from the rotation angle of the motor 9 detected by the resolver 15 and the vehicle speed by the vehicle speed sensor 14, The damper correction current value Ic is calculated by referring to the map showing the correlation with the current. This damper correction current value Ic is subtracted from the base current value Ia by the subtractor 35, thereby limiting the rotation of the motor 9 to obtain a stable steering feeling and improving the stability of the vehicle. . Since the steering rotation speed of the steering handle 2 is proportional to the rotation speed of the motor 9, the steering angle of the steering handle 2 detected by the steering angle sensor 13 is obtained by time differentiation instead of the motor rotation speed. The steering angular velocity may be used.

  Next, the steering torque sensor 12 will be described with reference to FIGS. As shown in FIG. 3, the steering shaft 3 includes an input shaft 41 on the steering handle 2 side, an output shaft 42 on the pinion 4 side, and a torsion bar 43 that coaxially connects the input shaft 41 and the output shaft 42. Have. Each end portion of the torsion bar 43 is connected to the input shaft 41 and the output shaft 42 so as not to rotate relative to each other. The torsion bar 43 is twisted when a rotational torque is input to the input shaft 41 or the output shaft 42 and relatively rotates both shafts 41 and 42. .

  A magnetic member 44 having a north pole and a south pole magnetized at a predetermined interval in the circumferential direction is integrally provided at the lower end of the input shaft 41. A flange portion 42a extending in the radial direction is provided at the upper end of the output shaft 42. The upper surface of the flange portion 42a (the surface on the input shaft 41 side) is opposed to the magnetic member 44 with a predetermined gap. In addition, a pair of MR sensors 45 disposed integrally at positions 180 degrees symmetrical with respect to the axis 41X of the input shaft 41 as a target axis are integrally formed. The rotation angle sensor 50 is constituted by the magnetic member 44 and the pair of MR sensors 45, and the pair of MR sensors 45 are fixed to the output shaft 42, whereby the relative rotation angle between the input shaft 41 and the output shaft 42 is detected. Is done. Further, the magnetic member 44 and the pair of MR sensors 45 are arranged in two upper and lower stages, respectively, and the steering torque sensor 12 shown in FIG.

  As shown in FIG. 4, each MR sensor 45 includes two MR elements 46 having a characteristic that an electric resistance changes according to the magnitude of the magnetic flux density when receiving an external magnetic field 47. A predetermined voltage is applied to circuits arranged in the circumferential direction of the magnetic member 44 and connected in series, and a voltage between the MR elements 46 is output. For example, when there are N poles in front of a pair of MR elements 46, each MR element 46 receives a magnetic field indicated by a white arrow in (A), and a boundary between the N poles and S poles in front of the pair of MR elements 46. If there is, the magnetic field received by each MR element 46 changes as indicated by the white arrow in (B). And the output which changed according to the state of such a magnetic field is converted into the circumferential direction position of the magnetic member 44 in the steering control apparatus 21, ie, a rotation angle. The principle of detection of the rotation angle by the rotation angle sensor 50 will be described below.

5A and 5B are explanatory diagrams of a detection state by the rotation angle sensor 50. FIG. 5A shows the positional relationship between the MR sensor 45 and the magnetic member 44, and FIG. 5B shows the magnetic member 44 shown in FIG. The magnetic field change in each MR sensor 45 when rotating counterclockwise (in the direction of the solid line arrow in the figure) is shown, and (C) shows the output change of each MR sensor 45 at this time. Also shows dashed arrows indicate the direction of the magnetic field, (B), the (1) the first 1MR sensor 45 ₁ side in (C), (2) is a first 2MR sensor 45 ₂ side, respectively, in (A) .

When in the position where the magnetic member 44 is shown in (A), as shown at the top of (B), the 1MR sensor 45 ₁ and the 2MR sensor 45 ₂ is hollow, respectively in the figure by two MR elements 46 A voltage corresponding to the magnetic field in the direction indicated by the arrow is output. When the voltage corresponding to the magnetic field state is outputted to a detection value according 1MR sensor 45 ₁ and the 2MR sensor 45 ₂ 0 respectively. When the magnetic member 44 from the position rotated in the counterclockwise of (A), the magnetic field is changed to the state shown in the lower part in order from the state shown at the top of (B), the 1MR sensor 45 ₁ and the 2MR sensor 45 Each ₂ detects +1. As shown in (A), for example, when the magnetic member 44 has eight poles, “+1” in the detection value indicates 22.5 degrees. When the magnetic field conditions change with the rotation of the magnetic member 44, the 1MR sensor 45 ₁ and the 2MR sensor 45 ₂ are "+2", detects a "+ 3". Further, when the state becomes the uppermost state from the state of “+3”, the detected value becomes “+4”.

With this rotation from the position shown in the magnetic member 44 (A) in the direction of the solid arrow, (C), the rotation of the positive direction is successively detected in the 1MR sensor 45 ₁ and the 2MR sensor 45 ₂ The Further, when the solid arrow in the opposite direction is the magnetic member 44 rotates, the rotation of the negative direction is detected in the 1MR sensor 45 ₁ and the 2MR sensor 45 _2.

However, the input shaft 41 and the output shaft 42, which are rotatably held, may rattle (axis shift) in the front-rear and left-right directions due to insufficient holding rigidity. As shown in FIG. 6, for example, when the magnetic member 44 moves relative to the MR sensor 45 in the direction of the white arrow due to the rattling of the input shaft 41 or the output shaft 42, the input shaft 41 and the output shaft 42 Toshafuto 42 and despite not rotate relative changes to (B), the magnetic field in the 1MR sensor 45 ₁ and the 2MR sensor 45 ₂ is the upper state lower state. At this time, in the 1MR sensor 45 ₁ "-1" is detected, in the 2MR sensor 45 ₂ "+1" is detected. In this state, when the magnetic member 44 rotates in the direction of the solid arrow in (A), the detection value of the _first MR sensor 451 is changed from “−1” to “0”, “0”, “ The detection value of the _second MR sensor 452 changes from “+1” to “+2”, “+3”, “+4” as indicated by a two-dot chain line in FIG. And change sequentially. That is, in the backward output of the phase between the ₁ second 1MR sensor 45 and the 2MR sensor 45 _2, a state shifted the same amount in absolute value.

Here, if the rotation angle sensor 50 is configured only by the _first MR sensor 451, the input shaft 41 is rotated counterclockwise by the relative movement of the magnetic member 44 in the direction of the white arrow in FIG. If the rotation angle sensor 50 is constituted only by the _second MR sensor 452, it is erroneously detected that the rotation has occurred, and the magnetic member 44 is relatively moved in the direction of the white arrow in (A). It is erroneously detected that the input shaft 41 is rotated clockwise.

Therefore, in this embodiment, obtaining the results obtained from the 1MR output of the sensor 45 _1, the rotation angle by taking the average of the results obtained from the output of the 2MR sensor 45 _2. Thereby, as indicated by a solid line in (C), it is possible to prevent an error in the relative rotation angle due to the rattling between the input shaft 41 and the output shaft 42, that is, an error in the rotational torque.

  Further, as shown in FIG. 7, the steering torque sensor 12 according to the embodiment includes a rotation angle sensor 50 including a magnetic member 44 and a pair of MR sensors 45 in two upper and lower stages. The magnetic member 44 of the rotation angle sensor 50 arranged on the upper side has a smaller dimension in the circumferential direction of the N pole and the S pole than the rotation angle sensor 50 arranged on the lower side. Each one has more. That is, the lower magnetic member 44 includes N combinations of N and S poles, whereas the upper magnetic member 44 includes N + 1 combinations of N and S poles. The pair of MR sensors 45 are disposed at the same angular position with respect to the output shaft 42. By arranging the magnetic member 44 in two upper and lower stages as described above, the detection accuracy of the steering torque sensor 12 can be improved by using the detection result of either the upper or lower rotation angle sensor 50 that outputs in a highly sensitive state. it can.

  In addition, since the upper and lower magnetic members 44 are gradually shifted in this manner, the phase difference D gradually increases as the rotation angle increases, as shown in FIG. Thus, when the magnetic member 44 rotates 90 degrees, the phase difference becomes 0 and the detected value difference becomes 1, and when the magnetic member 44 rotates once, the phase difference becomes 0 and the detected value difference becomes 4. That is, since the detected value and the phase difference thereof are determined according to the rotation angle of the magnetic member 44, the phase difference D between the output of the lower rotation angle sensor 50 and the output of the upper rotation angle sensor 50 is obtained to obtain the magnetic value. The absolute angle of the member 44, that is, the input shaft 41 can be detected with high accuracy.

  In this manner, the relative rotation angle between the input shaft 41 and the output shaft 42 is obtained, and the steering torque is obtained by multiplying the relative rotation angle by the spring constant of the torsion bar 43.

  Next, the steering angle sensor 13 will be described with reference to FIG. As shown in the figure, the steering shaft 3 is integrally provided with a magnetic member 44 having N and S poles magnetized at a predetermined interval in the circumferential direction. A vehicle body side member 48 fixed to the vehicle body is disposed around the steering shaft 3, and the vehicle body side member 48 has a predetermined gap so as to face the magnetic member 44. A pair of MR sensors 45 arranged at a position that is 180 degrees symmetrical about the axis 3X as a target axis are integrally formed. The rotation angle sensor 50 is configured by the magnetic member 44 and the pair of MR sensors 45. The magnetic member 44 and the pair of MR sensors 45 are respectively arranged in two upper and lower stages, and the two rotation angle sensors 50 constitute the steering angle sensor 13 shown in FIG.

  The steering angle sensor 13 detects the relative rotation angle of the steering shaft 3 with respect to the vehicle body side member 48, that is, the steering angle of the steering handle 2. The detection principle of each rotation angle sensor 50 is the same as that described for the steering torque sensor 12. Similar to the steering torque sensor 12, the magnetic member 44 of the upper rotation angle sensor 50 includes one more N pole and one S pole than the rotation angle sensor 50 disposed on the lower side. That is, the lower magnetic member 44 includes N combinations of N and S poles, whereas the upper magnetic member 44 includes N + 1 combinations of N and S poles. The pair of MR sensors 45 are arranged at the same angular position with respect to the steering shaft 3.

By configuring the vertical rotation angle sensor 50 as described above, the detection accuracy of the steering angle sensor 13 can be improved by using the detection result of the vertical rotation angle sensor 50 that is output in a highly sensitive state. Can do. Further, by subtracting the output of the upper rotation angle sensor 50 from the output of the lower rotation angle sensor 50 to obtain the output difference D, the absolute angle of the magnetic member 44, that is, the steering shaft 3, can be detected with high accuracy. The pair of MR sensors 45 are installed at positions 180 degrees symmetrical with respect to the axis 3X of the steering shaft 3 as a target axis, so that the steering shaft 3 rattles and moves relative to the vehicle body side member 48 (axis be displaced), the results obtained from the 1MR output of the sensor 45 _1, by using a mean value of the results obtained from the output of the 2MR sensor 45 _2, an error occurs in the absolute rotation angle of the steering shaft 3 Can not be.

  Further, since the error of the rotation angle of the steering shaft 3 can be canceled by using the detection results of the pair of MR sensors 45, the rotation angle can be detected accurately without the steering shaft 3 being assembled with high accuracy. The rotational angle can be accurately detected without assembling the shaft 3 with high rigidity. Accordingly, it is possible to reduce the cost and work man-hours required for assembly accuracy and assembly rigidity.

  Next, a rotation angle / torque sensor 16 according to another embodiment to which the rotation angle sensor according to the present invention is applied will be described with reference to FIG. In the description, the same members as those in the above-described embodiment are denoted by the same reference numerals, and redundant description is omitted.

  The rotation angle / torque sensor 16 combines the functions of the steering torque sensor 12 and the steering angle sensor 13 according to the above-described embodiment, and the steering torque acting on the pinion 4 (on the output shaft 42 side) and the steering handle 2 ( The steering angle of the input shaft 41 side) is detected.

  At the lower end of the input shaft 41, a magnetic member 44 having N poles and S poles magnetized at a predetermined interval in the circumferential direction is integrally provided in two upper and lower stages, and the upper end of the output shaft 42 is also provided in the circumferential direction. In addition, magnetic members 44 having N poles and S poles magnetized at predetermined intervals are integrally provided in two upper and lower stages. The vehicle body side member 48 disposed around the steering shaft 3 is positioned 180 degrees symmetrical with respect to the axis 3X of the steering shaft 3 as a target axis so as to face each magnetic member 44 with a predetermined gap. A total of eight MR sensors 45 are integrally formed with each pair arranged. Each of the magnetic members 44 and the pair of MR sensors 45 corresponding thereto constitutes four rotation angle sensors 50, and the four rotation angle sensors 50 constitute the rotation angle / torque sensor 16.

  The two rotation angle sensors 50 provided on the input shaft 41 detect the steering angle of the steering handle 2 by detecting the relative rotation angle of the input shaft 41 with respect to the vehicle body side member 48. Two rotation angle sensors 50 provided on the output shaft 42 detect the relative rotation angle of the output shaft 42 with respect to the vehicle body side member 48. Then, by subtracting the relative rotational angle of the output shaft 42 from the relative rotational angle of the input shaft 41, the relative rotational angle of both shafts 41, 42 is obtained, and by multiplying this value by the spring constant of the torsion bar 43, steering is performed. Torque is required.

In the upper and lower rotation angle sensors 50 provided on the input shaft 41 and the output shaft 42, the N pole and S pole of the upper magnetic member 44 are the N pole and S pole of the lower magnetic member 44, respectively. One is formed more than each. Thereby, the absolute angles of the input shaft 41 and the output shaft 42 can be detected with high accuracy. Further, the pair of MR sensors 45 are installed at positions that are 180 degrees symmetrical with respect to the axis 3X of the steering shaft 3 as a target axis, so that the input shaft 41 or the output shaft 42 rattles with respect to the vehicle body side member 48. even relative movement (axial displacement), the results obtained from the 1MR output of the sensor 45 _1, by using a mean value of the results obtained from the output of the 2MR sensor 45 _2, error in the absolute rotational angle detecting Can be prevented from occurring. By providing the rotation angle sensor 50 for each of the input shaft 41 and the output shaft 43, the input to the torsion bar is a disturbance in which the output shaft side is displaced first in time, or the driver in which the input shaft side is displaced first. It is possible to determine whether the intention is steering.

  Although the description of the specific embodiment is finished as described above, the present invention is not limited to the above embodiment and can be widely modified. For example, in the above embodiment, one rotation angle sensor 50 includes a pair of MR sensors 45 arranged symmetrically by 180 degrees, but four (two pairs) MR sensors 45 arranged symmetrically by 90 degrees are provided. You may prepare. In this way, it is possible to prevent a detection error due to an axial deviation even if the shaft is displaced in any direction. In the above embodiment, the MR sensor 45 having the MR element 46 is used as the magnetic detection element. However, a GMR sensor having a GMR element in which a nonmagnetic layer is sandwiched between two ferromagnetic layers may be used. . Furthermore, a sensor having a magnetic detection element other than these may be used as long as it detects a change in the magnetic field due to the N pole and the S pole. Moreover, in the said embodiment, although the rotation angle sensor 50 is arrange | positioned and used for two steps of upper and lower sides, it is naturally possible to use only one step. Even in this case, by providing a plurality of magnetic detection elements in the circumferential direction, it is possible to cancel a detection error due to a shaft shift. In addition to these changes, the specific configuration and arrangement of each member can be changed as appropriate without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 Electric power steering device 12 Steering torque sensor 13 Steering angle sensor 16 Rotation angle / torque sensor 21 Steering control device 41 Input shaft 41X Axis center 42 Output shaft 43 Torsion bar 44 Magnetic member 45 MR sensor 46 MR element 47 External magnetic field 48 Car body side Member 50 Rotation angle sensor

Claims (6)

A magnetic member provided integrally with the first shaft and magnetized with N and S poles at a predetermined interval in the circumferential direction of the first shaft;
A magnetic detection element that is disposed opposite to the magnetic member and detects a change in magnetic field due to the N pole and the S pole;
A rotation angle detection device, wherein a plurality of the magnetic detection elements are arranged at different positions in the circumferential direction of the first shaft.   The rotation angle detection device according to claim 1, wherein the plurality of magnetic detection elements are integrally provided on a second shaft that is coaxially connected to the first shaft via a torsion bar.   The rotation angle detection device according to claim 1, wherein the plurality of magnetic detection elements are arranged symmetrically with respect to a line passing through an axial center of the first shaft.   The plurality of magnetic detection elements are arranged so as to be 180 degrees symmetrical with respect to a line passing through an axial center of the first shaft. The rotation angle detection device described.   The rotation angle detection device according to any one of claims 1 to 4, wherein the magnetic detection element includes an MR element or a GMR element.   A power steering device comprising the rotation angle detection device according to any one of claims 1 to 5.

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