Patent application number | Description | Published |
20090128081 | ELECTRIC STEERING SYSTEM - An electric steering system is provided with: a steering torque detection unit which detects a steering torque acting on the shaft; a brushless motor which includes a rotor and a stator having multi-phase stator coils, and generates an assisting torque for assisting the steering torque; a current supply switching unit which drives the brushless motor; a rotary angle estimation unit which outputs an estimated rotary angle; a determination unit which determines whether or not the estimated rotary angle is appropriate by comparison with a direction of the steering torque; and a steering control unit which drives the brushless motor in accordance with the estimated rotary angle determined to be appropriate by the determination unit to control generation of the assisting torque. | 05-21-2009 |
20090266179 | MAGNETOSTRICTIVE TORQUE SENSOR AND ELECTRIC POWER STEERING APPARATUS - A magnetostrictive torque sensor includes first and second magnetostrictive films mounted on a pinion shaft and having different magnetic anisotropic properties, a first detecting coil disposed in facing relation to the first magnetostrictive film, a second detecting coil disposed in facing relation to the second magnetostrictive film, a transistor, and a detector for detecting a torque applied to the pinion shaft based on a first detected signal representative of a potential at the junction between the first detecting coil and the second detecting coil. | 10-29-2009 |
20090314573 | Magnetostrictive Torque Sensor and Electric Steering System - A magnetostrictive torque sensor comprising: a magnetostrictive film provided on a ferromagnetic shaft; a bias magnetization device which applies a bias magnetic field to the shaft to magnetize the shaft; and a detection device which detects a change in magnetism of the magnetostrictive film, wherein: a torque acting on the shaft calculated based on the detection results of the detection device; and the bias magnetization device applies a bias magnetic field to the shaft at a predetermined timing. | 12-24-2009 |
20100263457 | MAGNETOSTRICTIVE TORQUE SENSOR AND METHOD OF MANUFACTURING SAME - A magnetostrictive torque sensor includes a single magnetostrictive film disposed on a steering shaft, and first and second coils for detecting changes in a magnetic property of the magnetostrictive film. The single magnetostrictive film includes a first anisotropic region and a second anisotropic region, having respective magnetic anisotropies inverse to each other. The first coil is disposed in confronting relation to the first anisotropic region, whereas the second coil is disposed in confronting relation to the second anisotropic region. | 10-21-2010 |
20100263962 | MAGNETOSTRICTIVE TORQUE SENSOR AND ELECTRIC POWER STEERING APPARATUS - A magnetostrictive torque sensor includes a rotatable shaft rotatably supported by bearings, a magnetostrictive film disposed on the surface of the rotatable shaft, and a detecting coil that detects a change in a magnetic property of the magnetostrictive film. A hollow cylindrical ring is press-fitted over and fixed to the rotatable shaft near the magnetostrictive film, for example, near the right end of the magnetostrictive film. | 10-21-2010 |
20110035114 | MOTOR CONTROL DEVICE AND ELECTRIC STEERING SYSTEM - A motor control device includes: a rotation angle detection portion that detects a rotation angle of a motor and outputs a rotation angle signal; an abnormal condition detection portion that detects the presence or absence of an abnormal condition of the rotation angle detection portion; a rotation angle estimation portion that estimates the rotation angle of the motor and outputs an estimate rotation angle signal; and a driving control portion that controls driving of the motor on the basis of the rotation angle signal, which is output from the rotation angle detection portion, when the abnormal condition detection portion does not detect an abnormal condition of the rotation angle detection portion, and controls driving of the motor on the basis of the estimate rotation angle signal, which is output from the rotation angle estimation portion, when the abnormal condition detection portion detects an abnormal condition of the rotation angle detection portion. | 02-10-2011 |
20120199414 | ELECTRIC POWER STEERING APPARATUS - An electric power steering apparatus includes a motor control unit for controlling an electric motor operatively connected to a steering shaft. The motor control unit includes a first control unit for controlling a steering torque detected by a torque detecting unit so as to bring the steering torque to zero or to a first predetermined value, and a second control unit for controlling the steering torque detected by the torque detecting unit so as to bring the steering torque to a second predetermined value which is greater than zero or than the first predetermined value, based on an operational quantity detected by an operational-quantity detecting unit or a quantity representative of a vehicle behavior detected by a vehicle-behavior detecting unit. The motor control unit controls the electric motor based on an output signal from the first control unit and an output signal from the second control unit. | 08-09-2012 |
20120232759 | ELECTRIC POWER STEERING DEVICE - An electric power steering device wherein mechanical friction is electrically provided. A steering torque value is detected by a steering torque sensor according to the operation of a steering wheel. An assist current value is calculated by an assist control section on the basis of the steering torque value. A target current value based on the assist current value is determined. For providing friction to the operation of the steering wheel, a friction control section and a friction torque value/current value conversion section generate a corrected steering torque value. A second corrected target current value is created by correcting a first corrected target current value by a friction current value. The corrected steering torque value is obtained by correcting the steering torque value by a friction torque value. The target current value is generated, resulting in a motor being subjected to driving control. | 09-13-2012 |
20120271513 | ELECTRIC POWER STEERING APPARATUS - In the event of a failure of a first electric motor drive signal generator, e.g., the microcomputer, which generates a first electric motor drive signal for performing a feedback control, a second electric motor drive signal generator, e.g., a PWM signal generator, which is made up of discrete circuit components, directly converts a steering torque signal into a second electric motor drive signal. An electric motor, which generates the assistive steering force, is driven by the second electric motor drive signal. | 10-25-2012 |
20120273293 | ELECTRIC POWER STEERING APPARATUS - As a quotient, which is produced when the value of an assistive current for causing an electric motor to generate an assistive torque is divided by the value of a steering torque detected by a steering torque sensor, becomes greater, a greater phase-lag compensation (smaller phase-lead compensation) is performed on the steering torque detected by the steering torque sensor. Within a region in which the steering sensation is reduced, a greater phase-lead compensation is performed. | 11-01-2012 |
20140195122 | ELECTRIC POWER STEERING DEVICE - Provided is an electric power steering device in which the operation feeling is improved without a decrease in commercial value. A phase compensation unit performs a frequency shift on a compensation frequency band compensated by the phase compensation unit. The phase compensation unit performs phase-shift in the compensation frequency band through a frequency shift process, instead of an increase in compensation gain. Therefore, it is possible to minimize occurrences of minute vibrations and abnormal noise in the steering system including the motor that accompany an increase in gain, and to improve the operation feeling and commercial value. | 07-10-2014 |