JP2018197672A - Assembly structure of rotation angle sensor, relative angle detector, torque sensor, electric power steering device, and vehicle - Google Patents

Abstract

To provide an assembly structure of a rotation angle sensor capable of more precisely detecting an angle, and to provide a relative angle detector, a torque sensor, an electric power steering device, and a vehicle.SOLUTION: An assembly structure of a rotation angle sensor includes: a first shaft; a second shaft in which one end is connected to one end of the first shaft via a universal joint; a first multipolar magnet that is fixed to the first shaft, includes a circular outer peripheral surface with a first rotating shaft as a center axis when viewed from above the first rotating shaft as a rotating shaft of the first shaft, and allows different magnetic poles to be disposed alternately along a circumferential direction of an outer peripheral surface; and at least one first magnetic sensor that opposes the outer peripheral surface, is disposed on a plane including an intersection point between the first rotating shaft and a second rotating shaft as the rotating shaft of the second shaft, a point differing from an intersection point on the first rotating shaft, and a point differing from an intersection point on the second rotating shaft, and outputs an angle signal by detecting rotation of the first multipolar magnet.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a rotation angle sensor assembly structure, 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 an auxiliary steering force generated by a motor. The electric power steering device controls the motor based on the steering torque output from the torque sensor. The torque sensor calculates the steering torque from the steering angle detected by the assembly structure of the rotation angle sensor. For example, Patent Document 1 describes an example of an assembly structure (sensor assembly) of a rotation angle sensor. An assembly structure of a rotation angle sensor described in Patent Document 1 includes a magnet coupled to a first shaft and an electronic device coupled to a second shaft. An electronic device described in Patent Literature 1 includes a magnetoresistive sensing element, a processing circuit that is electrically connected to the magnetoresistive sensing element and generates a signal that displays at least one of an angle of a magnetic field and a steering torque, Is provided.

International Publication No. 2013/188058

  Here, the assembly structure of the rotation angle sensor is desired in terms of detection accuracy of the rotation angle.

  The present invention has been made in view of the above problems, and is an assembly structure of a rotation angle sensor capable of detecting an angle with higher accuracy, a relative angle detection device, a torque sensor, an electric power steering device, and a vehicle. The purpose is to provide.

  In order to achieve the above object, an assembly structure of a rotation angle sensor according to one aspect of the present invention includes a first shaft and a second shaft having one end connected to one end of the first shaft via a universal joint. And a circular outer peripheral surface fixed to the first shaft and having the first rotational axis as a central axis when viewed from above the first rotational axis that is the rotational axis of the first shaft, An intersection of a first multipole magnet in which different magnetic poles are alternately arranged along a direction, and a second rotation axis that faces the outer peripheral surface and that is the rotation axis of the first rotation shaft and the second shaft. , Arranged on a plane including a point different from the intersection point on the first rotation axis and a point different from the intersection point on the second rotation axis, and detecting the rotation of the first multipole magnet And at least one first magnetic sensor for outputting a signal.

  According to this, it can suppress that a 1st magnetic sensor and a 1st multipolar magnet displace to the direction orthogonal to a gap direction. Thereby, the error of the angle signal detected by the first magnetic sensor can be suppressed.

  An assembly structure of a rotation angle sensor according to an aspect of the present invention includes a first shaft and the first shaft that is fixed to the first shaft and viewed from above the first rotation shaft that is a rotation shaft of the first shaft. A first multipolar magnet having a circular outer peripheral surface having a rotational axis as a central axis, wherein different magnetic poles are alternately arranged along a circumferential direction of the outer peripheral surface, and the first rotational axis as a rotational axis. A worm wheel that rotates integrally with one shaft, a motor, a worm that rotates integrally with the shaft of the motor, meshes with the worm wheel, and transmits the rotational driving force of the motor to the first shaft; At least one of the first rotation axis and the plane that includes the meshing point of the worm and the worm wheel, and detects the rotation of the first multipole magnet and outputs an angle signal. Comprising 1 and the magnetic sensor.

  According to this, it can suppress that a 1st magnetic sensor and a 1st multipolar magnet displace to the direction orthogonal to a gap direction. Thereby, the error of the angle signal detected by the first magnetic sensor can be suppressed.

  As a desirable mode of the assembly structure of the rotation angle sensor, it is preferable that the first magnetic sensor outputs the angle signal by detecting the direction of magnetic flux penetrating the first magnetic sensor.

  A relative angle detection device according to one aspect of the present invention is connected to the assembly structure of the rotation angle sensor described above and the other end of the first shaft via a torsion bar at a position coaxial with the first rotation shaft. A third outer shaft that is fixed to the third shaft, and has a circular second outer peripheral surface with the first rotational axis as a central axis when viewed from above the first rotational shaft. A second multipole magnet in which different magnetic poles are alternately arranged along a circumferential direction; and a second multipole magnet disposed on the plane so as to face the second outer circumferential surface and detect rotation of the second multipole magnet. And at least one second magnetic sensor that outputs an angle signal, an angle calculation unit, and a difference calculation unit, wherein the angle calculation unit is based on the angle signal output by the first magnetic sensor. The first rotation angle of the polar magnet is calculated, and the second magnetic sensor outputs A second rotation angle of the second multi-pole magnet is calculated based on a degree signal, and the difference calculation unit rotates relative to the difference between the first angle and the second angle calculated by the angle calculation unit. Calculate the angle. Thereby, the angle calculation part can calculate a 1st angle and a 2nd angle with high precision based on the angle signal by which the error was suppressed. Therefore, the relative angle detection device can calculate the relative angle with high accuracy from the difference between the first angle calculated with high accuracy and the second angle calculated with high accuracy.

  As a desirable aspect of the relative angle detection device, the above-described structure for assembling the rotation angle sensor, and a third connected to the other end of the first shaft via a torsion bar at a position coaxial with the first rotation shaft. A shaft and a second outer peripheral surface that is fixed to the third shaft and has a circular second outer peripheral surface with the first rotational axis as a central axis when viewed from the first rotational axis, and along a circumferential direction of the second outer peripheral surface A second multipole magnet in which different magnetic poles are alternately arranged, and opposed to the second outer peripheral surface and arranged on the plane, and detects the rotation of the second multipole magnet and outputs an angle signal At least one second magnetic sensor, an angle calculator, and a difference calculator, the angle calculator based on an angle signal output from the first magnetic sensor. One rotation angle is calculated, and the angle output by the second magnetic sensor A second rotation angle of the second multipole magnet is calculated based on the signal, and the difference calculation unit calculates a relative rotation angle based on a difference between the first angle and the second angle calculated by the angle calculation unit. Is calculated. Thereby, the angle calculation part can calculate a 1st angle and a 2nd angle with high precision based on the angle signal by which the error was suppressed. Therefore, the relative angle detection device can calculate the relative angle with high accuracy from the difference between the first angle calculated with high accuracy and the second angle calculated with high accuracy.

  As a desirable aspect of the relative angle detection device, a first gear that rotates in synchronization with the third shaft, a second gear that meshes with the first gear and is driven to rotate by the rotation of the first gear, and a columnar 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, wherein the angle magnetic sensor is rotated once by the magnet. It is preferable that an angle signal of one cycle is output with a change in the magnetic field, and the product of the gear ratio of the second gear to the first gear and the number of magnetic poles of the second multipolar magnet is other than two. In addition, it is preferable that the angle calculation unit calculates a rotation speed of the second multipole magnet by executing a vernier calculation from an angle signal of the angle magnetic sensor and an angle signal output from the second magnetic sensor. Thereby, the angle calculation part can calculate the rotation speed of a 2nd multipole magnet.

  The torque sensor which concerns on 1 aspect of this invention is provided with the relative angle detection apparatus mentioned above, and the torque calculating part which calculates the torque added to the said torsion bar based on the said relative rotation angle. According to this, the torque sensor can calculate the torque with high accuracy based on the relative rotation angle calculated with high accuracy.

  An electric power steering apparatus according to an aspect of the present invention includes the torque sensor described above. Thereby, 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 an accurate auxiliary steering torque.

  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 device outputs an accurate auxiliary steering torque, the operability is improved.

  ADVANTAGE OF THE INVENTION According to this invention, the assembly structure of the rotation angle sensor which can detect an angle more accurately, a relative angle detection apparatus, a torque sensor, an electric power steering apparatus, and a vehicle can be provided.

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 diagram of the electric power steering apparatus according to the first embodiment. FIG. 3 is a perspective view schematically showing the torque sensor according to the first embodiment. FIG. 4 is a schematic diagram illustrating functional blocks of the torque sensor according to the first embodiment. FIG. 5 is an explanatory diagram for explaining a first plane on which the first magnetic sensor and the second magnetic sensor according to the first embodiment are arranged. FIG. 6 is an explanatory diagram illustrating a relationship between a waveform output from the first magnetic sensor according to the first embodiment and a magnetic pole. FIG. 7 is a perspective view showing the universal joint according to the first embodiment. FIG. 8 is a side view schematically showing the universal joint according to the first embodiment. FIG. 9 is an explanatory diagram for explaining a couple generated in the universal joint according to the first embodiment. FIG. 10 is a conceptual diagram illustrating an example of the relationship between the moment applied to the output shaft and the rotation angle of the universal joint according to the first embodiment. FIG. 11 is an explanatory diagram for explaining the direction of the magnetic flux of the first multipole magnet. FIG. 12 is a perspective view schematically showing a torque sensor according to the second embodiment. FIG. 13 is an explanatory diagram for explaining a second plane on which the first magnetic sensor and the second magnetic sensor according to the second embodiment are arranged. FIG. 14 is a partial cross-sectional view of the worm and the worm wheel according to the second embodiment. FIG. 15 is a perspective view schematically showing a torque sensor according to the third embodiment. FIG. 16 is a plan view for explaining the positional relationship between the angle magnetic sensor and the magnet according to the third embodiment. FIG. 17 is a schematic diagram illustrating functional blocks of a torque sensor according to the third embodiment. FIG. 18 is an explanatory diagram illustrating a relationship between the first rotation angle and the angle magnetic sensor detection angle and the magnetic poles of the first multipolar magnet according to the third embodiment.

  DESCRIPTION OF EMBODIMENTS Hereinafter, modes for carrying out the invention (hereinafter referred to as embodiments) will be described in detail with reference to the drawings. In addition, this invention is not limited by the following embodiment. In addition, constituent elements in the following embodiments include those that can be easily assumed by those skilled in the art, those that are substantially the same, and those in a so-called equivalent range. Furthermore, the constituent elements disclosed in the following embodiments can be appropriately combined.

(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 diagram 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, the electric power steering device 80 includes a steering wheel 81, a steering shaft 82, a steering force assist mechanism 83, a universal joint 84, and a lower shaft 85 in the order in which the force given by the operator is transmitted. And a universal joint 86, which are joined to the pinion shaft 87. The electric power steering device 80 includes an ECU (Electronic Control Unit) 90 as a motor control device and a torque sensor 94. The vehicle speed sensor 95 is provided in the vehicle body, and outputs the vehicle speed SV to the ECU 90 as a signal by CAN (Controller Area Network) communication.

  As shown in FIG. 2, the steering shaft 82 includes an input shaft 82a and an output shaft 82b. 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. One end of the output shaft 82 b is connected to the input shaft 82 a, and the other end of the output shaft 82 b is connected to the universal joint 84. In this embodiment, the input shaft 82a and the output shaft 82b are made of 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). )) And other general steel materials.

  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. 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 88a and a rack 88b. The pinion 88a is connected to the pinion shaft 87. The rack 88b meshes with the pinion 88a. The steering gear 88 converts the rotational motion transmitted to the pinion 88a into a linear motion by 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 speed reducing device 92 and a motor 93. The motor 93 is, for example, a brushless motor. The speed reducer 92 is, for example, a worm speed reducer. Torque generated by the motor 93 is transmitted to the worm wheel via the worm inside the speed reducer 92 and rotates the worm wheel. The reduction gear 92 increases the torque generated by the motor 93 by a worm and a worm wheel (worm gear). The speed reducer 92 gives auxiliary steering torque to the output shaft 82b. The electric power steering device 80 is a column assist system.

  The ECU 90 is a device that controls the operation of the motor 93. Electric power is supplied to the ECU 90 from the power supply device 99 (for example, a vehicle-mounted battery) while the ignition switch 98 is on. The ECU 90 acquires signals from the torque sensor 94, the vehicle speed sensor 95, and the rotation detection unit 23. Specifically, the ECU 90 acquires the steering torque T from the torque sensor 94. 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 an auxiliary steering command value based on the steering torque T based on the rotation angle signal acquired by the motor 93, the vehicle speed SV, and the operation information SY. Then, ECU 90 adjusts electric power value SX supplied to motor 93 based on the calculated auxiliary steering command value.

  The steering force of the operator (driver) input to the steering wheel 81 is transmitted to the speed reduction device 92 of the steering force assist mechanism 83 via the input shaft 82a. At this time, the ECU 90 acquires the steering torque T input to the input shaft 82 a from the torque sensor 94 and acquires the vehicle speed SV from the vehicle speed sensor 95. The ECU 90 controls the operation of the motor 93. The auxiliary steering torque created by the motor 93 is transmitted to the speed reducer 92.

  The steering torque (including 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 and displaces the wheel.

(Torque sensor)
Next, an assembly structure 300 for a rotation angle sensor according to the first embodiment and a torque sensor 94 using the same will be described with reference to FIGS. FIG. 3 is a perspective view schematically showing the torque sensor according to the first embodiment. FIG. 4 is a schematic diagram illustrating functional blocks of the torque sensor according to the first embodiment. A first rotation axis Ax1 illustrated in FIG. 3 indicates a rotation axis of the input shaft 82a as the first shaft and the output shaft 82b as the third shaft. A second rotation axis Ax2 shown in FIG. 3 indicates the rotation axis of the lower shaft 85 as the second shaft. The torque sensor 94 detects the steering torque T transmitted to the input shaft 82a. As shown in FIGS. 3 and 4, the torque sensor 94 includes a relative angle detection unit 100 and a torque calculation unit 25.

As shown in FIGS. 3 and 4, the relative angle detection unit 100 includes a first rotation angle sensor 12, a second rotation angle sensor 13, a storage unit 24, and a sensor calculation unit 200. The relative angle detection unit 100 calculates a relative angle Δθ _io that is a relative angle between the input shaft 82a and the output shaft 82b based on signals output from the first rotation angle sensor 12 and the second rotation angle sensor 13. The relative angle detection device. The relative angle detection unit 100 outputs the relative angle Δθ _io to the torque calculation unit 25. As shown in FIG. 3, the input shaft 82a and the output shaft 82b are connected by a torsion bar 82c. The torsion bar 82c is an elastic member formed of, for example, a steel material.

  As shown in FIG. 3, the first rotation angle sensor 12 includes a first multipolar magnet 10, a substrate 14, and a first magnetic sensor 15.

  As shown in FIG. 3, the first multipole magnet 10 is, for example, a ring-shaped magnet magnetized in the radial direction. The first multipole magnet 10 has S poles and N poles arranged alternately on the outer peripheral surface. For example, the first multipole magnet 10 is attached to the end of the input shaft 82a on the output shaft 82b side so as to be coaxial with the rotation shaft of the input shaft 82a. The number m of magnetic poles of the first multipolar magnet 10 is 20, for example, but is not limited thereto. For the first multipole magnet 10, for example, a neodymium magnet, a ferrite magnet, a samarium cobalt magnet, or the like is used according to the required magnetic flux density.

  FIG. 5 is an explanatory diagram for explaining a first plane on which the first magnetic sensor and the second magnetic sensor according to the first embodiment are arranged. The explanatory view shown in FIG. 5 is a schematic side view of the input shaft 82a, the torsion bar 82c, the output shaft 82b, the universal joints 84 and 86, and the lower shaft 85 viewed from a direction orthogonal to the first plane P1. The position A shown in FIG. 5 indicates the position of the end of the output shaft 82b on the input shaft 82a side, and is a point different from the connection point C. The position B shown in FIG. 5 indicates the position of the end of the lower shaft 85 on the universal joint 86 side, and is a point different from the connection point C. A connection point C shown in FIG. 5 is an intersection of the first rotation axis Ax1 that is the rotation axis of the input shaft 82a and the output shaft 82b and the second rotation axis Ax2 that is the rotation axis of the lower shaft 85. The first plane P1 shown in FIGS. 3 and 5 is a plane including the position A, the position B, and the connection point C. As shown in FIG. 3, the first magnetic sensor 15 faces the outer peripheral surface of the first multipole magnet 10. The range in which the first magnetic sensor 15 is disposed may be within a range in which the magnetic flux of the first multipole magnet 10 can be detected. As shown in FIG. 5, the first magnetic sensor 15 is disposed on the substrate 14 so as to be positioned on the first plane P <b> 1 including the position A, the position B, and the connection point C. More specifically, the first magnetic sensor 15 being positioned on the first plane P1 means that the reference point (the position of the magnetic detection element) of the first magnetic sensor 15 is positioned on the first plane P1. The board | substrate 14 is being fixed to the vehicle body, for example. The first magnetic sensor 15 is, for example, an AMR (Anisotropic Magneto Resistance) element and is an AMR sensor that can detect a change in the direction of magnetic flux, but is not limited thereto. The first magnetic sensor 15 may be any sensor that can detect a change in the direction of magnetic flux. The first magnetic sensor 15 may be a spin valve sensor, for example. A spin valve sensor is a device that sandwiches a nonmagnetic layer between a ferromagnetic pinned layer whose magnetization direction is fixed by an antiferromagnetic layer, etc., and a ferromagnetic free layer, and detects changes in the direction of magnetic flux. It is a sensor that can. Spin valve sensors include GMR (Giant Magneto Resistance) sensors and TMR (Tunnel Magneto Resistance) sensors. The first magnetic sensor 15 may be a circular vertical Hall sensor, for example. A circular vertical Hall sensor is a sensor that includes a plurality of Hall elements arranged on the circumference and can detect a change in the direction of magnetic flux. Since the structure and operating principle of the AMR sensor are known techniques, description thereof is omitted.

  FIG. 6 is an explanatory diagram illustrating a relationship between a waveform output from the first magnetic sensor according to the first embodiment and a magnetic pole. The explanatory diagram shown in FIG. 6 shows the relationship between the magnetic poles of the first multipolar magnet 10 facing the first magnetic sensor 15 and the waveform of the signal output by the first magnetic sensor 15. The input shaft mechanical angle shown on the horizontal axis in FIG. 6 indicates the mechanical angle (rotation angle) of the input shaft 82a.

As shown in FIGS. 4 and 6, the first magnetic sensor 15 generates one cycle of a sine wave signal sin θ _is and one cycle of a cosine wave signal cos θ _is every time the first multipole magnet 10 rotates by one magnetic pole. Output to the sensor calculation unit 200. The first multipole magnet 10 has 20 magnetic poles m. Therefore, as shown in FIG. 6, the rotation of the first multipolar magnet 10 by one magnetic pole corresponds to the rotation of the input shaft 82a by 18 degrees by the mechanical angle.

  As shown in FIG. 3, the second rotation angle sensor 13 includes a second multipolar magnet 11, a substrate 18, and a second magnetic sensor 19. The second multipole magnet 11 is the same as the first multipole magnet 10 except that it is attached to the end of the output shaft 82b on the input shaft 82a side and rotates in synchronization with the output shaft 82b.

  As shown in FIG. 3, the position of the second magnetic sensor 19 is disposed on the substrate 18 so as to face the outer peripheral surface of the second multipolar magnet 11 and to be positioned on the first plane P1. Other than that, the second magnetic sensor 15 is the same as the first magnetic sensor 15. The range in which the second magnetic sensor 19 is disposed only needs to be within a range in which the magnetic flux of the second multipolar magnet 11 can be detected. The board | substrate 18 is being fixed to the vehicle body, for example.

As shown in FIG. 4, the second magnetic sensor 19 generates a one-cycle sine wave signal sin θ _os and a one-cycle cosine wave signal cos θ _os every time the second multipole magnet 11 rotates by one magnetic pole. Output to 200.

  The rotation angle sensor assembly structure 300 according to the first embodiment includes a lower shaft 85, a universal joint 84, an output shaft 82 b, the second multipolar magnet 11, and the second magnetic sensor 19.

  The storage unit 24 stores information output from the sensor calculation unit 200. The storage unit 24 is a memory that stores information such as the following formula (1) described below. Memory is a volatile or nonvolatile semiconductor memory such as RAM (Random Access Memory), ROM (Read Only Memory), flash memory, EPROM (Erasable Programmable Read Only Memory), and EEPROM (Electrically Erasable Programmable Read Only Memory), Magnetic disks, flexible disks, optical disks, compact disks, mini disks, and DVDs (Digital Versatile Discs) are applicable.

  As shown in FIG. 4, the sensor calculation unit 200 includes an angle calculation unit 202, an angle calculation unit 204, and a difference calculation unit 206.

  The angle calculation unit 202 causes the storage unit 24 to store the magnetic poles at positions facing the first magnetic sensor 15 when the first multipole magnet 10 is located at the reference position. The reference position of the first multipole magnet 10 is a predetermined position of the first multipole magnet 10. Specifically, the angle calculation unit 202 substitutes 0 for the magnetic pole determination number n stored in the storage unit 24 when the first multipole magnet 10 is located at the reference position.

The angle calculation unit 202 calculates the first magnetic sensor reference angle θ _ib when the first multi-pole magnet 10 is located at the reference position by the equation (1). Here, the sine wave signal sin [theta _IS and the cosine wave signal cos [theta] _IS shown in Formula (1) is the value when the first multi-pole magnet 10 is located at the reference position. The angle calculation unit 202 stores the first magnetic sensor reference angle θ _ib in the storage unit 24.

θ _ib = arctan (sin θ _is / cos θ _is ) (1)

The angle calculation unit 202 adds 1 to the magnetic pole determination number n when the cosine wave signal cos θ _is changes from positive to negative and the sine wave signal sin θ _is is positive. The angle calculation unit 202 adds 1 to the magnetic pole determination number n when the cosine wave signal cos θ _is changes from negative to positive and the sine wave signal sin θ _is negative. The angle calculation unit 202 subtracts 1 from the magnetic pole determination number n when the cosine wave signal cos θ _is changes from negative to positive and the sine wave signal sin θ _is is positive. The angle calculation unit 202 subtracts 1 from the magnetic pole determination number n when the cosine wave signal cos θ _is changes from positive to negative and the sine wave signal sin θ _is negative. According to this, the angle calculation unit 202 can count the number of times the magnetic pole facing the first magnetic sensor 15 has changed according to the rotation direction of the first multipole magnet 10.

The angle calculation unit 202 calculates the first rotation angle θ _{is according} to Expression (2). The angle calculation unit 202 outputs the calculated first rotation angle θ _is to the difference calculation unit 206.

θ _is = arctan (sin θ _is / cos θ _is ) + n × 180−θ _ib (2)

Angle calculation unit 204, based on the sine wave signal sin [theta _os and the cosine wave signal cos [theta] _os, by storing the magnetic pole located at the position facing the second magnetic sensor 19 in the storage unit 24, and the sine wave signal sin [theta _os Except for calculating the second rotation angle θ _os based on the cosine wave signal cos θ _os and outputting the second rotation angle θ _os to the difference calculation unit 206, the same as the angle calculation unit 202. Note that the method for calculating the second rotation angle θ _os is the same as the method for calculating the first rotation angle θ _is , and thus the description thereof is omitted. Note that the relative angle detection unit 100 of the present embodiment includes an angle calculation unit 204 in addition to the angle calculation unit 202, and the angle calculation unit 202 and the angle calculation unit 204 function. The angle calculation unit 202 may perform the processing of the angle calculation unit 204 without the angle calculation unit 204 described above. Alternatively, the angle calculation unit 202 may be processed without the angle calculation unit 202 described above.

Based on the first rotation angle θ _is and the second rotation angle θ _os , the difference calculation unit 206 calculates a relative angle Δθ _io that is a relative angle difference between the input shaft 82a and the output shaft 82b. Specifically, the difference calculation unit 206 calculates the relative angle Δθ _io using Equation (3). The difference calculation unit 206 outputs the calculated relative angle Δθ _io to the torque calculation unit 25. The number m of magnetic poles shown in Expression (3) indicates the number of magnetic poles of the first multipolar magnet 10 and the second multipolar magnet 11.

Δθ _io = (θ _is −θ _os ) / m (3)

The torque calculator 25 calculates the steering torque T based on the relative angle Δθ _io . For example, the torque calculator 25 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 25 calculates the steering torque T based on the relative angle Δθ _io input from the difference calculator 206 and the relationship between the stored relative angle Δθ _io and the steering torque T. The torque calculation unit 25 outputs the calculated steering torque T to the ECU 90.

  Next, with reference to FIGS. 7 to 10, the couples F1 and F2 generated in the universal joint 84 and the displacement of the input shaft 82a and the output shaft 82b caused by the couples F1 and F2 will be described. FIG. 7 is a perspective view showing the universal joint according to the first embodiment. FIG. 8 is a side view schematically showing the universal joint according to the first embodiment. A straight line L0 illustrated in FIG. 8 is a straight line drawn from the first rotation axis Ax1 in a direction orthogonal to the first plane P1. A gap direction 46 shown in FIG. 8 is a direction in which the first magnetic sensor 15 and the first rotation axis Ax1 approach each other. A gap orthogonal direction 48 shown in FIG. 8 is a direction orthogonal to the gap direction 46.

  As shown in FIGS. 7 and 8, the universal joint 84 includes yokes 50 and 52 and a cross shaft free joint 54. One end of the yoke 50 is U-shaped, and a pair of opposing arm portions 56 and 58 are provided. The other end of the yoke 50 is fixed to the output shaft 82 b of the steering shaft 82. The yoke 50 is fixed to the output shaft 82b by inserting a pinch bolt into the pinch bolt hole 60. The arm portions 56, 58 are provided with a pair of bearing holes 62, 64 provided to face the arm portions 56, 58, respectively. As shown in FIG. 8, the cross shaft free joint 54 includes joints 66, 68, 70, and 72. The joints 66 and 70 are rotatably fixed to the bearing holes 62 and 64 via bearings. A rotation axis Ax3 illustrated in FIG. 8 indicates rotation axes of the joint 66 and the joint 70. The torque Tm shown in FIG. 8 indicates the torque applied to the joints 66 and 70 via the yoke 50 from the output shaft 82b.

  The yoke 52 has a pair of arm portions 74 and 76 provided at one end thereof fixed to the joints 68 and 72 through bearings, and the other end fixed to the lower shaft 85. Except for the above, it is the same as the yoke 50. A rotation axis Ax4 shown in FIG. 8 indicates the rotation axes of the joint 68 and the joint 72.

  FIG. 9 is an explanatory diagram for explaining a couple generated in the universal joint according to the first embodiment. As shown in FIG. 9, couples F <b> 1 and F <b> 2 are generated in a direction parallel to the first rotation axis Ax <b> 1 at the action point D that is the end of the joint 66 and the action point E that is the end of the joint 70. The couples F1 and F2 are generated by torque Tm applied to the joints 66 and 70 from the output shaft 82b through the yoke 50. The joint 66 and the joint 70 are connected to the output shaft 82b via the yoke 50. The output shaft 82b is connected to the input shaft 82a via a torsion bar 82c. Accordingly, the couples F1 and F2 apply a moment M to the yoke 50, the output shaft 82b, and the input shaft 82a. The moment M is a force that rotates the yoke 50, the output shaft 82b, and the input shaft 82a about the rotation axis Ax3. That is, the moment M displaces the input shaft 82a and the output shaft 82b in the direction of the rotation axis Ax3.

FIG. 10 is a conceptual diagram illustrating an example of the relationship between the moment applied to the output shaft and the rotation angle of the universal joint according to the first embodiment. The vertical axis in FIG. 10 indicates the moment M when the torque Tm applied to the joints 66 and 70 is constant. The horizontal axis of FIG. 10 indicates an angle θ ₀ (see FIG. 8) that is an angle formed by the straight line L0 and the rotation axis Ax3. As shown in FIG. 10, the moment M becomes maximum when the value of the angle θ ₀ is 90 degrees or 270 degrees. The rotation axis Ax3 is located in the first plane P1 when the angle θ ₀ is 90 degrees or 270 degrees. That is, the displacement of the input shaft 82a and the output shaft 82b due to the moment M is the largest when the rotation axis Ax3 is located in the first plane P1. Further, the displacement of the input shaft 82a and the output shaft 82b due to the moment M is the smallest when the rotation axis Ax3 is orthogonal to the first plane P1 (θ ₀ is 0 degree or 180 degrees). Therefore, the assembly structure 300 of the rotation angle sensor can suppress the displacement of the input shaft 82a and the output shaft 82b in the gap orthogonal direction 48 (direction orthogonal to the first plane P1). According to this, in the assembly structure 300 of the rotation angle sensor, the first multipole magnet 10 fixed to the input shaft 82a and the second multipole magnet 11 fixed to the output shaft 82b are displaced in the gap orthogonal direction 48. Can be suppressed. As a result, the rotation angle sensor assembly structure 300 can suppress relative displacement of the first multipolar magnet 10 and the first magnetic sensor 15 in the gap orthogonal direction 48. Further, the rotation angle sensor assembly structure 300 can suppress relative displacement of the second multipolar magnet 11 and the second magnetic sensor 19 in the gap orthogonal direction 48.

FIG. 11 is an explanatory diagram for explaining the direction of the magnetic flux of the first multipole magnet. The explanatory view shown in FIG. 11 is a part of a plan view of the first magnetic sensor 15 and the first multipole magnet 10 viewed from the direction of the first rotation axis Ax1. As shown in FIG. 11, the direction of the magnetic flux (lines of magnetic force) 10 m of the first multipole magnet 10 changes more greatly in the gap orthogonal direction 48 than in the gap direction 46. On the other hand, the first magnetic sensor 15 outputs an angle signal based on the direction of the magnetic flux penetrating the first magnetic sensor 15. Therefore, when the first magnetic sensor 15 is relatively displaced in the gap orthogonal direction 48 with respect to the first multipole magnet 10, the influence of the error becomes large. The angle signal output from the second magnetic sensor 19 is the same as that of the first magnetic sensor 15 when the second magnetic sensor 19 is relatively displaced with respect to the second multipolar magnet 11 in the gap orthogonal direction 48. , The effect of error becomes larger. As described above, the rotation angle sensor assembly structure 300 can suppress the first magnetic sensor 15 and the second magnetic sensor 19 from being relatively displaced in the gap orthogonal direction 48 with respect to the opposing magnets. Therefore, the rotation angle sensor assembly structure 300 can reduce errors in the angle signals output from the first magnetic sensor 15 and the second magnetic sensor 19. As a result, the angle calculation unit 202 can calculate the first rotation angle θ _is with high accuracy based on the angle signal in which the error output from the first magnetic sensor 15 is reduced. Further, the angle calculation unit 202 can calculate the second rotation angle θ _os with high accuracy based on the angle signal with which the error output from the second magnetic sensor 19 is reduced. Therefore, the relative angle detection unit 100 using the rotation angle sensor assembly structure 300 can calculate the relative angle Δθ _io between the first rotation angle θ _is and the second rotation angle θ _os with high accuracy. Further, the torque sensor 94 can calculate the steering torque T with high accuracy based on the relative angle Δθ _io .

(Embodiment 2)
FIG. 12 is a perspective view schematically showing a torque sensor according to the second embodiment. The torque sensor 94a according to the second embodiment is the same as the torque sensor 94 except that the relative angle detection unit 100a is provided instead of the relative angle detection unit 100. 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.

  The relative angle detection unit 100 a includes a first rotation angle sensor 12 a instead of the first rotation angle sensor 12 and a second rotation angle sensor 13 a instead of the second rotation angle sensor 13. Is a relative angle detection device similar to the relative angle detection unit 100.

  As shown in FIG. 12, the first rotation angle sensor 12 a is the same as the first rotation angle sensor 12 except that a first magnetic sensor 15 a is provided instead of the first rotation angle sensor 12. The first magnetic sensor 15a is the same as the first magnetic sensor 15 except that the first magnetic sensor 15a is disposed on the substrate 14 so as to face the outer peripheral surface of the first multipole magnet 10 and to be positioned on the second plane P2. It is the same. The second plane P2 will be described later in detail. Here, the range in which the first magnetic sensor 15a is disposed may be within a range in which the magnetic flux of the first multipole magnet 10 can be detected.

  As shown in FIG. 12, the second rotation angle sensor 13 a is the same as the second rotation angle sensor 13 except that a second magnetic sensor 19 a is provided instead of the second magnetic sensor 19. The second magnetic sensor 19a is the same as the second magnetic sensor 19 except that the second magnetic sensor 19a is disposed on the substrate 18 so as to face the outer peripheral surface of the second multipole magnet 11 and to be positioned on the second plane P2. It is the same. Here, the range in which the second magnetic sensor 13a is disposed may be within a range in which the magnetic flux of the second multipolar magnet 11 can be detected.

  FIG. 13 is an explanatory diagram for explaining a second plane on which the first magnetic sensor and the second magnetic sensor according to the second embodiment are arranged. 13 is a schematic side view of the input shaft 82a, the torsion bar 82c, the output shaft 82b, the universal joint 84, the lower shaft 85, the speed reducer 92, and the motor 93 viewed from a direction orthogonal to the second plane P2. It is. FIG. 14 is a partial cross-sectional view of the worm and the worm wheel according to the second embodiment. In FIG. 14, components other than the speed reducer 92, the motor 93, the output shaft 82 b, the second multipolar magnet 11, the second magnetic sensor 19 a, and the substrate 18 are omitted.

  As shown in FIGS. 13 and 14, the speed reducer 92 includes a worm wheel 96, a worm 97, a ball bearing 102 a, a ball bearing 102 b, and a speed reducer housing 104. The position A shown in FIG. 13 indicates the position of the end of the output shaft 82b on the input shaft 82a side, and is a point different from the connection point C. A gear meshing point G shown in FIG. 13 indicates a position where a worm tooth 97 a formed on a part of the worm 97 contacts a worm wheel tooth 96 a formed on the worm 96. The gear meshing point G shown in FIG. 13 appears as a point when viewed from the direction orthogonal to the second plane P2, but in this embodiment, the gear meshing point G is the actual meshing range between the worm teeth 97a and the worm wheel teeth 96a. Is included. The gear meshing point G may be a part of the actual meshing range between the worm teeth 97a and the worm wheel teeth 96a. The first magnetic sensor 15a is disposed so as to be positioned on a second plane P2 including the connection point C, the first rotation axis Ax1 including the position A, and the gear meshing point G.

  As shown in FIG. 14, the worm wheel 96 is rotatably held by the speed reducer housing 104. The worm 97 is coupled to the shaft 91 of the motor 93 by a spline or an elastic coupling. The worm 97 is rotatably fixed to the speed reducer housing 104 via a ball bearing 102a and a ball bearing 102b. The worm teeth 97 a formed on a part of the worm 97 mesh with the worm wheel teeth 96 a formed on the worm wheel 96.

  The rotational driving force of the motor 93 is transmitted to the worm wheel 96 through the worm 97. The reduction gear 92 increases the torque of the motor 93 by the worm wheel 96 and the worm 97. The torque increased by the worm wheel 96 and the worm 97 is transmitted to the output shaft 82b as auxiliary steering torque. The second plane P2 shown in FIGS. 13 and 14 is a plane including the position A, the connection point C, and the gear meshing point G.

  The rotational angle sensor assembly structure 300 a according to the second embodiment includes a worm wheel 96, a worm 97, an output shaft 82 b, the second multipolar magnet 11, and the second magnetic sensor 19.

  Next, with reference to FIGS. 13 and 14, the force F3 that the output shaft 82b receives from the reduction gear 92 and the displacement of the input shaft 82a and the output shaft 82b due to the force F3 will be described.

  As shown in FIGS. 13 and 14, a gear reaction force N is applied to the worm wheel 96 from the worm 97. The gear reaction force N is generated by a rotational driving force transmitted from the motor 93 to the worm wheel 96 through the shaft 91 and the worm 97. The gear reaction force N is applied in a perpendicular direction (gap direction 46) lowered from the gear meshing point G to the first rotation axis Ax1. The worm wheel 96 applies a gear reaction force N received from the worm 97 to the output shaft 82b as a force F3. The force F3 is applied in the same direction as the gear reaction force N. The gap direction 46 is included in the second plane P2. According to this, the force F3 does not have a component orthogonal to the second plane P2. The output shaft 82b is connected to the input shaft 82a via a torsion bar 82c. Accordingly, the force F3 does not apply a force to the input shaft 82a and the output shaft 82b in a direction orthogonal to the second plane P2 (gap orthogonal direction 48). According to this, the assembly structure 300a of the rotation angle sensor can suppress the displacement of the input shaft 82a and the output shaft 82b in the direction orthogonal to the second plane P2. Thereby, in the assembly structure 300a of the rotation angle sensor, the first multipole magnet 10 fixed to the input shaft 82a and the second multipole magnet 11 fixed to the output shaft 82b are displaced in the gap orthogonal direction 48. Can be suppressed. As a result, the assembly structure 300a of the rotation angle sensor can suppress relative displacement of the first multipole magnet 10 and the first magnetic sensor 15a in the gap orthogonal direction 48. Furthermore, the assembly structure 300a of the rotation angle sensor can suppress the relative displacement of the second multipolar magnet 11 and the second magnetic sensor 19a in the gap orthogonal direction 48.

Similar to the first magnetic sensor 15 according to the first embodiment, the angle signal output by the first magnetic sensor 15 a is obtained when the first magnetic sensor 15 a is relatively displaced with respect to the first multipole magnet 10 in the gap orthogonal direction 48. , The effect of error becomes larger. Similar to the second magnetic sensor 19 according to the first embodiment, the angle signal output by the second magnetic sensor 19a is obtained when the second magnetic sensor 19a is relatively displaced in the gap orthogonal direction 48 with respect to the second multipole magnet 11. , The effect of error becomes larger. As described above, the assembly structure 300a of the rotation angle sensor can suppress relative displacement in the gap orthogonal direction 48 with respect to the magnets facing the first magnetic sensor 15a and the second magnetic sensor 19a. Therefore, the assembly structure 300a of the rotation angle sensor can reduce the error of the angle signal output from the first magnetic sensor 15a and the second magnetic sensor 19a. As a result, the angle calculation unit 202 can calculate the first rotation angle θ _is with high accuracy based on the angle signal in which the error output from the first magnetic sensor 15a is reduced. Further, the angle calculation unit 202 can calculate the second rotation angle θ _os with high accuracy based on the angle signal in which the error output from the second magnetic sensor 19a is reduced. Therefore, the relative angle detector 100a using the rotation angle sensor assembly structure 300a can calculate the relative angle Δθ _io between the first rotation angle θ _is and the second rotation angle θ _os with high accuracy. Further, the torque sensor 94a can calculate the steering torque T with high accuracy based on the relative angle Δθ _io .

(Embodiment 3)
FIG. 15 is a perspective view schematically showing a torque sensor according to the third embodiment. The torque sensor 94b according to the third embodiment includes the first gear 26b, the second gear 28b, the magnet 30b, and the angle magnetic sensor 32b, and includes the sensor calculation unit 200b instead of the sensor calculation unit 200. Different from the sensor 94. 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.

  FIG. 16 is a plan view for explaining the positional relationship between the angle magnetic sensor and the magnet according to the third embodiment. As shown in FIGS. 15 and 16, the first gear 26b is attached to the input shaft 82a. The first gear 26b rotates in synchronization with the input shaft 82a.

  As shown in FIG. 15, the second gear 28b is fixed so as to be rotatable about the rotation axis Ax5. The second gear 28b is fixed to the vehicle body, for example. As shown in FIGS. 15 and 16, the second gear 28b is arranged to mesh with the first gear 26b. The second gear 28b rotates in conjunction with the first gear 26b. The gear ratio of the first gear 26b to the second gear 28b is, for example, 3. That is, when the first gear 26b rotates once, the second gear 28b rotates three times.

  As shown in FIGS. 15 and 16, the magnet 30b is a cylindrical permanent magnet. The magnet 30b is magnetized in the radial direction of the magnet 30b. The magnet 30b is disposed inside the second gear 28b. The magnet 30b rotates in synchronization with the second gear 28b with the rotation axis Ax5 as the rotation axis. For the magnet 30b, 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 magnetized pattern of the magnet 30b may be a pattern that allows the angle magnetic sensor 32b to detect the rotation of the magnet 30b.

FIG. 17 is a schematic diagram illustrating functional blocks of a torque sensor according to the third embodiment. As shown in FIGS. 15 and 16, the angle magnetic sensor 32b is disposed on the rotation axis Ax5. The angle magnetic sensor 32b is disposed to face the upper surface of the magnet 30b. The angle magnetic sensor 32b is fixed to the vehicle body, for example. As shown in FIG. 17, the angle the magnetic sensor 32b, each time the magnet 30b is rotated 1, and outputs a cosine wave signal cos [theta] _an, sinusoidal signals sin [theta _an, and 1 cycle of one period to the sensor computing unit 200b. The angle magnetic sensor 32b is, for example, a spin valve sensor, but is not limited thereto. The angle magnetic sensor 32b may be, for example, an AMR sensor or a circular vertical Hall sensor.

As shown in FIG. 17, the sensor calculation unit 200b is the same as the sensor calculation unit 200 except that it includes a θ _an calculation unit 208b.

The θ _an calculating unit 208b calculates the angle magnetic sensor detection angle θ _an by the equation (4).

θ _an = arctan {sin θ _an / cos θ _an } (4)

FIG. 18 is an explanatory diagram illustrating a relationship between the first rotation angle and the angle magnetic sensor detection angle and the magnetic poles of the first multipolar magnet according to the third embodiment. The input shaft mechanical angle shown on the horizontal axis in FIG. 18 indicates the mechanical angle (rotation angle) of the input shaft 82a. The electrical angle shown in the upper part of FIG. 18 indicates the first rotation angle θ _is detected by the first magnetic sensor 15. The electrical angle shown in the lower part of FIG. 18 indicates the angle magnetic sensor detection angle θ _an detected by the angle magnetic sensor 32b. In the first multipole magnet 10 shown in the upper part of FIG. With reference to FIG. 18, _an example of a method in which the θ _an arithmetic unit 208b calculates the rotation speed of the input shaft 82a when the number m of magnetic poles of the first multipole magnet 10 is eight will be described. Since the gear ratio of the first gear 26b to the second gear 28b is 3, the magnet 30b rotates 1080 degrees when the input shaft 82a rotates 360 degrees. The angle magnetic sensor 32b outputs a signal of one cycle when the magnet 30b rotates 360 degrees. Accordingly, as shown in FIG. 18, the angle magnetic sensor detection angle θ _an has a mechanical angle of the input shaft 82a and a period of 120 degrees.

The first rotation angle θ _is outputs a signal of one cycle every time the magnetic pole at the position facing the first magnetic sensor 15 changes by one magnetic pole pair. Therefore, as shown in FIG. 18, the first rotation angle θ _is has a period of 90 degrees as the mechanical angle of the input shaft 82a. As described above, the angle magnetic sensor detection angle θ _an and the first rotation angle θ _is are the mechanical angles of the input shaft 82a and have the same phase (electrical angle) every 360 degrees. That is, the angle of the angle magnetic sensor detection angle θ _an and the first rotation angle θ _is match each time the input shaft 82a rotates once. The θ _an calculation unit 208b receives the input stored in the storage unit 24 in accordance with the rotation direction of the first multipole magnet 10 when the phase of the angle magnetic sensor detection angle θ _an coincides with the first rotation angle θ _is. 1 is added to or subtracted from the shaft rotational speed nb. According to this, the θ _an operation unit 208b can count the number of rotations of the input shaft 82a (multi-rotation detection) even when the input shaft 82a rotates more than one rotation.

Note that the torque sensor 94b according to the second embodiment may calculate the input shaft rotational speed nb by vernier calculation of the angle magnetic sensor detection angle θ _an and the first rotation angle θ _is . In this case, the number of magnetic poles m and the gear ratio of the second gear 28b to the first gear 26b are appropriately selected so that the period of the angle magnetic sensor detection angle θ _{an and} the period of the first rotation angle θ _is have different values. That's fine. The gear ratio of the second gear 28b to the first gear 26b may be different from, for example, a value obtained by dividing 2 by the number of magnetic poles m. According to this, the period of the angle magnetic sensor detection angle θ _{an and} the period of the first rotation angle θ _is can be set to different values. As a result, the input shaft speed nb can be calculated by vernier calculation.

DESCRIPTION OF SYMBOLS 10 1st multipole magnet 11 2nd multipole magnet 12, 12a 1st rotation angle sensor 13, 13a 2nd rotation angle sensor 15, 15a 1st magnetic sensor 19, 19a 2nd magnetic sensor 25 Torque calculating part 26b 1st gear 28b Second gear 30b Magnet 32b Angle magnetic sensor 80 Electric power steering device 81 Steering wheel 82 Steering shaft 82a Input shaft (first shaft)
82b Output shaft (third shaft)
82c Torsion bar 84, 86 Universal joint 85 Lower shaft (second shaft)
90 ECU (motor control device)
92 Decelerator 93 Motor 94, 94a, 94b Torque sensor 95 Vehicle speed sensor 96 Worm wheel 97 Worm 98 Ignition switch 99 Power supply device 100, 100a Relative angle detector (relative angle detector)
101 Vehicle 200, 200b Sensor calculation unit P1 First plane P2 Second plane

Claims (10)

A first shaft;
A second shaft having one end connected to one end of the first shaft via a universal joint;
A circular outer peripheral surface fixed to the first shaft and having the first rotational axis as a central axis when viewed from above the first rotational axis that is the rotational axis of the first shaft; and in a circumferential direction of the outer peripheral surface A first multipole magnet in which different magnetic poles are alternately arranged, and
An intersection point of the second rotation axis that is opposed to the outer peripheral surface and that is the rotation axis of the first shaft and the second shaft, a point different from the intersection point on the first rotation axis, and the second And at least one first magnetic sensor disposed on a plane including a point different from the intersection on the rotation axis and detecting an angle of the first multipole magnet and outputting an angle signal. Assembly structure of rotation angle sensor. A first shaft;
A circular outer peripheral surface fixed to the first shaft and having the first rotational axis as a central axis when viewed from above the first rotational axis that is the rotational axis of the first shaft; and in a circumferential direction of the outer peripheral surface A first multipole magnet in which different magnetic poles are alternately arranged, and
A worm wheel that rotates integrally with the first shaft about the first rotation axis;
A motor,
A worm that rotates integrally with the shaft of the motor, meshes with the worm wheel, and transmits the rotational driving force of the motor to the first shaft;
An angle signal is output by detecting the rotation of the first multipole magnet, disposed on a plane that faces the outer peripheral surface and includes the first rotating shaft and the meshing point of the worm and the worm wheel. And at least one first magnetic sensor. An assembly structure of a rotation angle sensor.   The rotation angle sensor assembly structure according to claim 1 or 2, wherein the first magnetic sensor outputs the angle signal by detecting a direction of a magnetic flux penetrating the first magnetic sensor. . An assembly structure of the rotation angle sensor according to claim 1;
A third shaft connected to the other end of the first shaft via a torsion bar at a position coaxial with the first rotation axis;
A magnetic pole fixed to the third shaft and having a circular second outer peripheral surface with the first rotational axis as a central axis when viewed from the first rotational axis, and being different along the circumferential direction of the second outer peripheral surface Second multipole magnets alternately arranged, and
At least one second magnetic sensor that faces the second outer peripheral surface and is disposed on the plane and that detects rotation of the second multipole magnet and outputs an angle signal;
An angle calculator,
A difference calculation unit,
The angle calculation unit calculates a first rotation angle of the first multipole magnet based on an angle signal output from the first magnetic sensor, and performs the second operation based on an angle signal output from the second magnetic sensor. Calculating the second rotation angle of the multipole magnet;
The difference calculation unit calculates a relative rotation angle from a difference between the first angle and the second angle calculated by the angle calculation unit. The assembly structure of the rotation angle sensor according to claim 2;
A third shaft connected to the other end of the first shaft via a torsion bar at a position coaxial with the first rotation axis;
A magnetic pole fixed to the third shaft and having a circular second outer peripheral surface with the first rotational axis as a central axis when viewed from the first rotational axis, and being different along the circumferential direction of the second outer peripheral surface Second multipole magnets alternately arranged, and
At least one second magnetic sensor that faces the second outer peripheral surface and is disposed on the plane and that detects rotation of the second multipole magnet and outputs an angle signal;
An angle calculator,
A difference calculation unit,
The angle calculation unit calculates a first rotation angle of the first multipole magnet based on an angle signal output from the first magnetic sensor, and performs the second operation based on an angle signal output from the second magnetic sensor. Calculating the second rotation angle of the multipole magnet;
The difference calculation unit calculates a relative rotation angle from a difference between the first angle and the second angle calculated by the angle calculation unit. A first gear that rotates in synchronization with the third shaft;
A second gear meshing with the first gear and driven to rotate by rotation of the first gear;
A magnet that is cylindrical in shape and is magnetized in the radial direction of the cylinder and rotates integrally with the second gear;
An angle magnetic sensor disposed on the rotation axis of the magnet,
The angle magnetic sensor outputs an angle signal of one period by a magnetic field change of one rotation of the magnet,
The relative angle detection device according to claim 4 or 5, wherein a product of a gear ratio of the second gear to the first gear and the number of magnetic poles of the second multipolar magnet is other than two.   The angle calculation unit calculates a rotational speed of the second multipole magnet by performing a vernier calculation from an angle signal of the angle magnetic sensor and an angle signal output from the second magnetic sensor. Item 7. The relative angle detection device according to Item 6. A relative angle detection device according to any one of claims 4 to 7,
And a torque calculator that calculates torque applied to the torsion bar based on the relative rotation angle.   An electric power steering apparatus comprising the torque sensor according to claim 8.   A vehicle comprising the electric power steering device according to claim 9.

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