JP2009085841A - Torque detector and electric power steering device - Google Patents

Abstract

A torque detector and an electric power steering apparatus including the torque detector are reduced in size.
A first shaft 11 and a second shaft 12 that are coaxially connected via a connecting shaft 2 and a bearing 21 that directly or indirectly supports the second shaft 12 are fixed along the circumferential direction. A ring-shaped permanent magnet 16 magnetized with multiple poles, a sensor yoke 15 fixed to the first shaft 11 and opposed to the permanent magnet 16 from one side in the axial direction to form a magnetic circuit together with the permanent magnet 16, and the permanent magnet 16 And a magnetic flux collecting yoke 25 that forms a magnetic circuit together with the sensor yoke 15, and a magnetic flux detector 27 that detects the magnetic flux induced by the sensor yoke 15 and the magnetic flux collecting yoke 25, and includes the first shaft 11 and the second shaft. 12 is a torque detector 1 that detects torque applied to any one of 12 based on the output of the magnetic flux detector 27.
[Selection] Figure 1

Description

  The present invention relates to a torque detector and an electric power steering device (EPS), and is suitable for application to an electric power steering device of an automobile, for example.

Conventionally, various torque detectors applied to an electric power steering device of an automobile have been proposed and put into practical use. For example, a ring-shaped permanent magnet that is multipolarly magnetized along the circumferential direction, a pair of ring-shaped sensor members that face the outer peripheral surface of the permanent magnet, and magnetic flux detection arranged between these sensor members And a torque detector that detects torque generated on the permanent magnet side or the sensor member side based on the magnetic flux detected by the magnetic flux detector (see Patent Document 1). In such a torque detector, a technique for detecting a magnetic flux using two magnetic flux detectors has also been proposed (see Patent Document 2).
JP-A-2-162221 JP-A-2-141616

  However, in order to detect torque based on the output of the magnetic flux detector in the conventional torque detector as described in the above-mentioned Patent Document 1, etc., the sensor member receives a predetermined amount of magnetic flux generated from the permanent magnet. Therefore, it is necessary to increase the area where the sensor member and the permanent magnet face each other. Therefore, when the conventional torque detector is adopted, the sensor member and the permanent magnet have to be configured to be long in the axial direction. As a result, it is difficult to downsize the torque detector itself, and the torque detector is mounted. There has been a problem that it is difficult to reduce the size of the electric power steering device.

  The present invention has been made in view of such circumstances, and an object thereof is to realize downsizing of a torque detector and an electric power steering device.

  In order to achieve the above object, a torque detector according to the present invention directly or indirectly supports a first shaft and a second shaft, which are coaxially connected via a connecting shaft, and the second shaft. A ring-shaped permanent magnet fixed to the bearing and multipolarly magnetized along the circumferential direction, and a sensor fixed to the first shaft, facing the permanent magnet from one side in the axial direction, and forming a magnetic circuit together with the permanent magnet A yoke, a magnetic flux collecting yoke that forms a magnetic circuit together with the permanent magnet and the sensor yoke, and a magnetic flux detector that detects the magnetic flux induced by the sensor yoke and the magnetic flux collecting yoke, the first shaft and the second shaft The torque applied to any one of them is detected based on the output of the magnetic flux detector.

  When such a configuration is adopted, in order to fix the permanent magnet to the bearing that directly or indirectly supports the second shaft, it is necessary to provide a fixing allowance for fixing the permanent magnet to the second shaft on the second shaft. Absent. Accordingly, the axial length of the entire torque detector can be shortened, and a torque detector having a small axial dimension can be obtained.

  In the torque detector, the magnetism collecting yoke and the sensor yoke can be opposed to each other in the radial direction.

  When such a configuration is adopted, since the magnetism collecting yoke and the sensor yoke are opposed to each other in the radial direction, the axial length can be further shortened, and the torque detector can be further reduced in size.

  In the torque detector, the magnetism collecting yoke and the sensor yoke can be opposed to each other in the axial direction.

  The electric power steering device according to the present invention generates an auxiliary steering torque from an electric motor in response to a steering torque applied to a steering wheel, and transmits the auxiliary steering torque to an output shaft of a steering mechanism. An apparatus comprising the torque detector.

  By adopting such a configuration, the overall length of the electric power steering apparatus can be reduced by reducing the axial length, and the installation of the electric power steering apparatus having a limited mounting space can be facilitated.

  According to the present invention, it is possible to reduce the size of the torque detector and the electric power steering apparatus.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<First Embodiment>
Initially, the torque detector 1 which concerns on 1st Embodiment of this invention is demonstrated using FIGS. 1-4. The torque detector 1 according to the present embodiment generates an auxiliary steering torque by an electric motor corresponding to the steering torque applied to the steering wheel, decelerates by a speed reducer, and transmits it to the output shaft of the steering mechanism. It is provided in a steering device.

  As shown in FIG. 1, the torque detector 1 includes a first shaft 11 and a second shaft 12 connected by a torsion bar (connection shaft) 2 that is a torsion element. The 1st axis | shaft 11 and the 2nd axis | shaft 12 are comprised by the column shape, The center axis | shaft and the center axis | shaft of the torsion bar 2 are extended on the straight line. A flat sensor yoke 15 is attached to the first shaft 11 so as to extend outward in the radial direction and is molded with a resin 18.

  The second shaft 12 includes a bearing 21 having a plurality of rolling elements 21C between the inner ring 21A and the outer ring 21B, and a bearing 22 having a plurality of rolling elements 22C between the inner ring 22A and the outer ring 22B. The worm wheel 23 is fixed to the second shaft 12 between the bearings 21 and 22. A ring-shaped permanent magnet 16 that is multipolarly magnetized in the circumferential direction is attached to the sensor yoke 15 on the axial end surface of the inner ring 21A of the one bearing 21 that supports the second shaft 12 on the sensor yoke 15 side. It is fixedly arranged so as to face the surface in the axial direction.

  Here, as a method of fixing the permanent magnet 16 to the inner ring 21A, for example, the permanent magnet 16 made of a plastic magnet is formed integrally with the inner ring 21A of the bearing 21, or the permanent magnet 16 made of a rubber magnet is used as the inner ring of the bearing 21. The permanent magnet 16 is held by a holder and the holder is caulked to the inner ring 21A of the bearing 21, or the permanent magnet 16 is directly attached to the inner ring 21A of the bearing 21 with an adhesive or the like. There are methods, and these methods can be selected according to the situation.

  As shown in FIGS. 2 and 3, the sensor yoke 15 is disposed between the plurality of first sensor yoke portions 15A and the first sensor yoke portion 15A, and is coaxial and the same as the first sensor yoke portion 15A. (Or substantially the same) and a plurality of second sensor yoke portions 15B arranged on a plane. Thus, by arranging the first and second sensor yoke portions 15A and 15B on the same (or substantially the same) plane, they can be integrated with a small amount of the resin material 18 and the cost can be reduced. it can. The first sensor yoke portions 15A and the second sensor yoke portions 15B are alternately arranged along the circumferential direction.

  The first and second sensor yoke portions 15A and 15B are formed in a flat plate shape having the same (or substantially the same) thickness. Thus, by forming the first and second sensor yoke portions 15A and 15B in a flat plate shape, the axial length of the first and second sensor yoke portions 15A and 15B can be shortened. The entire device can be downsized. Further, by forming the first and second sensor yokes 15A and 15B with the same (or substantially the same) thickness, when processing with a press, processing can be performed with a single iron plate, and processing costs can be reduced. .

  The number of first sensor yoke portions 15 </ b> A and the number of second sensor yoke portions 15 </ b> B are both selected to be the same as half the number of poles of permanent magnet 16. The first and second sensor yoke portions 15A and 15B are arranged and integrated in such a state that the first sensor yoke portion 15A and the second sensor yoke portion 15B mesh with each other in a non-contact state. Is done.

  The permanent magnet 16 is configured by magnetizing an annular hard magnetic material alternately to the north or south pole at a predetermined angular interval in the circumferential direction. Since the permanent magnet 16 in this embodiment is alternately magnetized to the N pole and the S pole at intervals of about 22.5 °, it has a total of 16 poles. As a magnet material constituting the permanent magnet 16, a ferrite magnet, a rare earth magnet, a metal magnet, a sintered magnet, a plastic magnet, a rubber magnet, or the like can be used.

  Magnetic collecting yokes 25 are arranged on the inner and outer peripheral sides of the sensor yoke 15. As shown in FIGS. 1 to 3, the magnetism collecting yoke 25 includes a ring-shaped first magnetism collecting yoke portion 25 </ b> A and a first magnetism collecting yoke portion having a smaller diameter than the first magnetism collecting yoke portion 25 </ b> A. And a ring-shaped second magnetism collecting yoke portion 25B arranged coaxially with 25A. Each of the first magnetism collecting yoke portion 25A and the second magnetism collecting yoke portion 25B is formed by curving a belt-like plate in an arc shape and connecting both ends to form an annular shape.

  As shown in FIG. 1, the magnetic flux collecting yoke 25 includes a first magnetic flux collecting yoke portion 25 </ b> A that faces the outer peripheral portion of the sensor yoke 15 in the circumferential direction, and a second magnetic flux collecting yoke portion 25 </ b> B that is inside the sensor yoke 15. It is fixed to a stationary member (not shown) so as to face the circumferential portion in the circumferential direction. By arranging the magnetic collecting yoke 25 over the entire circumference of the sensor yoke 15 in this way, it is possible to prevent the occurrence of measurement errors due to the relative angle fluctuation between the sensor yoke 15 and the magnetic collecting yoke 25.

  The magnetic flux collecting yoke 25 is provided with a magnetic flux concentrating portion 26. More specifically, as shown in FIGS. 1 to 3, the first magnetic flux concentrating portion constituting part which is a half of the magnetic flux concentrating portion 26 from a part of the first magnetic collecting yoke portion 25 </ b> A toward the radially outer side. 26A is formed, and the second magnetic flux concentration, which is the other half of the magnetic flux concentration portion 26, extends radially outward from the second magnetic flux collecting yoke portion 25B so as to face the gap 26A. A component part 26B is formed. And the magnetic flux detector 27 is arrange | positioned between 26 A of 1st magnetic flux concentration part structure parts and the 2nd magnetic flux concentration part structure part 26B. As shown in FIG. 1, the magnetic flux detector 27 is molded and integrated with the resin 19 together with the first magnetic flux concentrating portion constituting portion 26 </ b> A and the second magnetic flux concentrating portion constituting portion 26 </ b> B.

  By providing the magnetic flux concentrating portion 26 in the magnetic flux collecting yoke 25 in this manner, the magnetic flux passing through the magnetic collecting yoke 25 can be concentrated on the magnetic flux concentrating portion 26, and the magnetic flux detector 27 can easily detect the magnetic flux. Can do. Moreover, the magnetic flux detector 27 can be easily installed by providing the first and second magnetic flux concentrating portion constituting portions 26A and 26B.

  As the magnetic flux detector 27, a device capable of detecting a magnetic flux, such as a Hall element, MR element, MI element, or the like is used. In the present embodiment, two magnetic flux detectors 27 are used. This is because by using the two magnetic flux detectors 27, the sensitivity can be doubled by taking the output difference, and the zero point drift can be canceled. Further, by using two magnetic flux detectors 27, the sensor signal can be duplicated and the reliability can be improved. If three or more magnetic flux detectors 27 are used, even if one magnetic flux detector 27 fails, highly reliable data can be obtained by the remaining two or more normal magnetic flux detectors 27. Can do.

  Next, operation | movement of the torque detector 1 which concerns on this embodiment is demonstrated using FIG.

  FIG. 4 is a schematic diagram of a magnetic circuit in the torque detector 1 according to the present embodiment. In the torque detector 1, as shown in FIG. 4A, when the relative angle between the sensor yoke 15 and the permanent magnet 16 is “0”, the respective center lines are the N pole and S pole of the permanent magnet 16. The first and second sensor yoke portions 15A and 15B are fixed to the first shaft 11 and the permanent magnet 16 is fixed to the inner ring 21A of the bearing 21 so as to coincide with the boundary in the axial direction. Therefore, when the relative angle between the sensor yoke 15 and the permanent magnet 16 is “0”, the area of the first and second sensor yoke portions 15A and 15B facing the north pole of the permanent magnet 16, and the permanent magnet 16 The area of the portion facing the S pole is the same.

  In this state, the magnetic flux emitted from the N pole of the permanent magnet 16 enters the S pole of the permanent magnet 16 through the first and second sensor yoke portions 15A and 15B. When the relative angle between the sensor yoke 15 and the permanent magnet 16 is “0”, the number of magnetic fluxes entering the first sensor yoke portion 15A and the second sensor yoke portion 15B is the same as the number of outgoing magnetic fluxes. Therefore, the magnetic flux emitted from the permanent magnet 16 does not pass through the magnetic flux detector 27.

  On the other hand, in the torque detector 1, as shown in FIG. 4 (B), the sensor yoke 15 is moved relative to the permanent magnet 16 from the state shown in FIG. The first sensor yoke portion 15 </ b> A is opposed to only the N pole portion (or S pole portion) of the permanent magnet 16, and the second sensor yoke portion 15 </ b> B is S of the permanent magnet 16. The relative angle between the sensor yoke 15 and the permanent magnet 16 is the maximum when only the pole portion (or the N pole portion) is opposed. In this state, the number of magnetic fluxes entering and exiting the first and second sensor yoke portions 15A and 15B loses balance.

  When the sensor yoke 15 rotates in the right direction relative to the permanent magnet 16, as shown in FIG. 4B, the magnetic flux emitted from the N pole of the permanent magnet 16 is outer peripheral from the first sensor yoke portion 15A. First magnetic flux collecting yoke portion 25A, first magnetic flux concentrating portion constituting portion 26A, magnetic flux detector 27, second magnetic flux concentrating portion constituting portion 26B, inner peripheral second magnetic collecting yoke portion 25B and second The second sensor yoke portion 15B is sequentially entered into the S pole of the permanent magnet 16. On the other hand, when the sensor yoke 15 rotates relative to the permanent magnet 16 in the left direction, the magnetic flux emitted from the N pole of the permanent magnet 16 is the second magnetism collection on the inner circumference side from the second sensor yoke portion 15B. The yoke portion 25B, the second magnetic flux concentrating portion constituting portion 26B, the magnetic flux detector 27, the first magnetic flux concentrating portion constituting portion 26A, the first magnetic collecting yoke portion 25A on the outer peripheral side, and the first sensor yoke portion 15A are sequentially provided. Via, it enters the south pole of the permanent magnet 16.

  When the sensor yoke 15 rotates to the right relative to the permanent magnet 16 and the relative angle between the sensor yoke 15 and the permanent magnet 16 is between “0” and the maximum angle, the sensor yoke 15 The magnetic flux corresponding to the relative angle between the permanent magnet 16 and the permanent magnet 16 is changed from the first sensor yoke portion 15A to the outer peripheral first magnetic flux collecting yoke portion 25A, the first magnetic flux concentration portion constituting portion 26A, the magnetic flux detector 27, the first The second magnetic flux concentrating portion constituting portion 26B, the inner peripheral second magnetic flux collecting yoke portion 25B, and the second sensor yoke portion 15B are sequentially passed into the S pole of the permanent magnet 16. On the other hand, when the sensor yoke 15 rotates to the left relative to the permanent magnet 16 and the relative angle between the sensor yoke 15 and the permanent magnet 16 is between “0” and the maximum angle, the sensor yoke 15 The magnetic flux according to the relative angle between the permanent magnet 16 and the second sensor yoke portion 15B is changed from the second sensor yoke portion 15B to the inner peripheral second magnetic flux collecting yoke portion 25B, the second magnetic flux concentration portion constituting portion 26B, the magnetic flux detector 27, The first magnetic flux concentrating portion constituting portion 26A, the outer peripheral first magnetic flux collecting yoke portion 25A, and the first sensor yoke portion 15A sequentially enter the south pole of the permanent magnet 16.

  In the torque detector 1 configured as described above, the sensor yoke 15 is fixed to the first shaft 11, the permanent magnet 16 is fixed to the inner ring 21 </ b> A of the bearing 21 that supports the second shaft 12, and the first Since the first shaft 11 and the second shaft 12 are connected via the torsion bar 2, when a torsional torque acts between the first shaft 11 and the second shaft 12, the magnitude of the torsional torque ( (Torsional torque amount) and direction appear as a relative angle (including direction) between the sensor yoke 15 and the permanent magnet 16. Therefore, the magnitude and direction of the torsion torque acting between the first shaft 11 and the second shaft 12 can be detected based on the number of magnetic fluxes detected by the magnetic flux detector 27 and the direction thereof.

  In the torque detector 1 according to the embodiment described above, the magnitude and direction of the torsion torque acting between the first shaft 11 and the second shaft 12 are determined by the relative angle between the sensor yoke 15 and the permanent magnet 16. It is detected as the number of magnetic fluxes passing through the magnetic flux detector 27 along with the change and the direction thereof. In this case, since the permanent magnet 16 is fixed to the bearing 21 that supports the second shaft 12, it is not necessary to provide a fixing margin for fixing the permanent magnet 16 to the second shaft 12 in the second shaft 12. . Therefore, the axial length of the torque detector 1 as a whole can be shortened, and the torque detector 1 having a small axial dimension can be obtained.

  Further, in the torque detector 1 according to the embodiment described above, since the magnetism collecting yoke 25 and the sensor yoke 15 are opposed to each other in the radial direction, the axial length can be further reduced, and the torque detector 1 can be further reduced in size.

  Further, by incorporating the torque detector 1 according to the embodiment described above into the electric power steering apparatus, the entire electric power steering apparatus can be reduced in length in the axial direction, and the mounting space can be reduced. Installation of a limited electric power steering device can be facilitated.

Second Embodiment
Subsequently, a torque detector 30 according to a second embodiment of the present invention will be described with reference to FIGS. 5 and 6. The torque detector 30 according to this embodiment is obtained by changing the configuration of the sensor yoke and the magnetic flux collecting yoke of the torque detector 1 according to the first embodiment, and other configurations are substantially the same as those of the first embodiment. Are identical. For this reason, the description will be focused on the different configurations, and the same reference numerals will be given to the same components as those in the first embodiment, and detailed description thereof will be omitted.

  As shown in FIGS. 5 and 6, in the torque detector 30 according to the present embodiment, the sensor yoke 31 has a smaller diameter than the ring-shaped first sensor yoke portion 31A and the first sensor yoke portion 31A. The ring-shaped second sensor yoke portion 31B is arranged coaxially and on the same (or substantially the same) plane as the first sensor yoke portion 31A. Thus, by arrange | positioning the 1st and 2nd sensor yoke parts 31A and 31B on the same (or substantially the same) plane, these can be integrated with few resin and cost can be reduced.

  The first and second sensor yoke portions 31A and 31B are formed in a flat plate shape having the same (or substantially the same) thickness. Thus, by forming the first and second sensor yoke portions 31A and 31B in a flat plate shape, the axial length of the first and second sensor yoke portions 31A and 31B can be shortened. The entire device can be downsized. Further, by forming the first and second sensor yokes 31A and 31B with the same (or substantially the same) thickness, when processing with a press, processing can be performed with one iron plate, and processing costs can be reduced.

  On the inner peripheral portion of the first sensor yoke portion 31A, a trapezoidal convex portion 40 and a concave portion 41 projecting to the side where the second sensor yoke portion 31B in the radial direction is present (the radial inner side) are provided along the circumferential direction. A trapezoidal convex part 42 and a concave part 43 projecting to the side (radial outer side) where the first sensor yoke part 31A in the radial direction is present on the outer peripheral part of the second sensor yoke part 31B. Are alternately formed along the circumferential direction.

  The number of convex portions 40 (concave portions 41) of the first sensor yoke portion 31A and the number of convex portions 42 (concave portions 43) of the second sensor yoke portion 31B are both the same as half the number of poles of the permanent magnet 16. Has been selected. The first and second sensor yoke portions 31A and 31B have the convex portion 40 and the concave portion 41 of the first sensor yoke portion 31A and the concave portion 43 and the convex portion 42 of the second sensor yoke portion 31B. They are integrated in a state where they mesh with each other in a non-contact state.

  The permanent magnet 16 is disposed on one side of the sensor yoke 31 in the axial direction, and the magnetism collecting yoke 45 is disposed on the other side in the axial direction. The magnetism collecting yoke 45 has a ring-shaped first magnetism collecting yoke portion 45A and a diameter smaller than that of the first magnetism collecting yoke portion 45A, and is arranged coaxially and in the same plane as the first magnetism collecting yoke portion 45A. And a ring-shaped second magnetism collecting yoke portion 45B.

  In the magnetism collecting yoke 45, the first magnetism collecting yoke portion 45A continuously faces the outer peripheral portion of the first sensor yoke portion 31A in the entire circumferential direction, and the second magnetism collecting yoke portion 45B is the second sensor. It is fixed to a stationary member (not shown) so as to face the inner peripheral portion of the yoke portion 31B continuously in the entire circumferential direction. By arranging the magnetic flux collecting yoke 45 over the entire circumference of the first and second sensor yoke portions 31A and 31B in this way, measurement errors caused by relative angle fluctuations between the sensor yoke 31 and the magnetic flux collecting yoke 45 are reduced. Occurrence can be prevented.

  Also in the torque detector 30 configured in this way, the sensor yoke 31 is fixed to the first shaft 11, the permanent magnet 16 is fixed to the inner ring 21 </ b> A of the bearing 21 that supports the second shaft 12, and the first Since the first shaft 11 and the second shaft 12 are connected via the torsion bar 2, when a torsional torque acts between the first shaft 11 and the second shaft 12, the magnitude of the torsional torque ( (Torsion torque amount) and direction appear as a relative angle (including direction) between the sensor yoke 31 and the permanent magnet 16. Therefore, the magnitude and direction of the torsion torque acting between the first shaft 11 and the second shaft 12 can be detected based on the number of magnetic fluxes detected by the magnetic flux detector 27 and the direction thereof.

  In the torque detector 30 according to the embodiment described above, the magnitude and direction of the torsional torque that has acted between the first shaft 11 and the second shaft 12 are represented by the relative angle between the sensor yoke 31 and the permanent magnet 16. It is detected as the number of magnetic fluxes passing through the magnetic flux detector 27 along with the change and the direction thereof. In this case, since the permanent magnet 16 is fixed to the bearing 21 that supports the second shaft 12, it is not necessary to provide a fixing margin for fixing the permanent magnet 16 to the second shaft 12 in the second shaft 12. . Therefore, the axial length of the torque detector 30 as a whole can be shortened, and the torque detector 30 having a small axial dimension can be obtained.

  Further, by incorporating the torque detector 30 according to the embodiment described above into the electric power steering apparatus, the entire electric power steering apparatus can be reduced in length in the axial direction, and can be reduced in the mounting space. Installation of a limited electric power steering device can be facilitated.

It is sectional drawing which shows schematic structure of the torque detector which concerns on 1st Embodiment of this invention. It is a perspective view of the torque detector shown in FIG. It is a disassembled perspective view of the torque detector shown in FIG. It is the schematic of the magnetic circuit for demonstrating operation | movement of the torque detector shown in FIG. It is a perspective view of the torque detector which concerns on 2nd Embodiment of this invention. FIG. 6 is an exploded perspective view of the torque detector shown in FIG. 5.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 * 30 ... Torque detector, 2 ... Torsion bar (connection shaft), 11 ... 1st axis | shaft, 12 ... 2nd axis | shaft, 15.31 ... Sensor yoke, 16 ... Permanent magnet, 21 ... Bearing, 21A ... Inner ring , 25 · 45... Magnetic collecting yoke, 27... Magnetic flux detector.

Claims (4)

A first shaft and a second shaft connected coaxially via a connecting shaft;
A ring-shaped permanent magnet that is fixed to a bearing that directly or indirectly supports the second shaft and is multipolarly magnetized along the circumferential direction;
A sensor yoke fixed to the first shaft, facing the permanent magnet from one side in the axial direction, and forming a magnetic circuit with the permanent magnet;
A magnetic flux collecting yoke that forms the magnetic circuit together with the permanent magnet and the sensor yoke;
A magnetic flux detector for detecting the magnetic flux induced by the sensor yoke and the magnetic flux collecting yoke;
With
A torque applied to any one of the first axis and the second axis is detected based on an output of the magnetic flux detector,
Torque detector. The magnetism collecting yoke and the sensor yoke are arranged so as to face each other in the radial direction.
The torque detector according to claim 1. The magnetism collecting yoke and the sensor yoke are arranged so as to face each other in the axial direction.
The torque detector according to claim 1. An electric power steering device that generates an auxiliary steering torque from an electric motor in response to a steering torque applied to a steering wheel and transmits the auxiliary steering torque to an output shaft of a steering mechanism,
A torque detector according to any one of claims 1 to 3 is provided.
Electric power steering device.

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