A vehicle steering device (11) is provided that performs steering of a vehicle in response to operation of a steering wheel (13) operated when the traveling direction of the vehicle is changed. The vehicle steering device (11) includes a first steering assist device having a first steering torque sensor (23), a first assist motor (51), and a first EPS control unit (37), and a second steering assist device having a second steering torque sensor (25), a second assist motor (57), and a second EPS control unit (39). The first and second EPS control units (37, 39) perform driving control of the first and second assist motors (51, 57) independently from each other. Even if either one of the two control units (37, 39) respectively controlling driving of the two assist motors (51, 57) fails into an abnormal situation, such an abnormal situation can be brought under control quickly and soundly.

A vehicle steering device (11) is provided that performs steering of a vehicle in response to operation of a steering wheel (13) operated when the traveling direction of the vehicle is changed. The vehicle steering device (11) includes a first steering assist device having a first steering torque sensor (23), a first assist motor (51), and a first EPS control unit (37), and a second steering assist device having a second steering torque sensor (25), a second assist motor (57), and a second EPS control unit (39). The first and second EPS control units (37, 39) perform driving control of the first and second assist motors (51, 57) independently from each other. Even if either one of the two control units (37, 39) respectively controlling driving of the two assist motors (51, 57) fails into an abnormal situation, such an abnormal situation can be brought under control quickly and soundly.

An intermittent failure diagnostic system that, in addition to a failure detection of a conventional failure threshold, appropriately sets an intermittent diagnostic threshold at which a probability of false-positive detection of the intermittent failure is equal to a probability of false-positive detection of the conventional failure, more accurately detects the intermittent failure, suppresses an unprepared system down and improves the reliability, may be used with an electric power steering apparatus.

An electric power steering device includes a restricting portion that is provided on at least one of surfaces of a housing and a worm wheel, the surfaces facing each other. The restricting portion is configured to restrict movement of the worm wheel to maintain a meshing relationship between a worm and the worm wheel that allows torque transmission between the worm and the worm wheel, when fixing of the worm wheel to an output shaft of a power assist actuator in an axial direction of the output shaft is released and the worm wheel is moved in the axial direction.

A method of controlling a power steering system including at least one course control function, whereby a position setpoint is determined automatically according to a reference course that a vehicle is to be made to follow, then a motor setpoint applied to an assistance motor is adjusted accordingly, the method including a safety function which is distinct from the course control function and meets a higher ASIL safety level according to ISO-26262 standard, said safety function including a diagnostics subfunction according to which a control parameter such as the angular position of the steering wheel, the driver torque applied to the steering wheel, or the rate at which the steering wheel is turned is monitored in order to detect the onset of an alert situation considered to be hazardous, then an intervention subfunction according to which, if an alert situation is detected, the course control function is neutralized.

An inverter system failure is detected on the basis of the currents of respective phases detected by a current detection unit when carrying out switching control in accordance with a first drive mode in which all switching elements on a lower-side arm are switched on and all switching elements on an upper-side arm are switched off, and the currents of respective phases detected by the current detection unit when carrying out switching control in accordance with a second drive mode in which all of the switching elements on the upper-side arm are switched on and all of the switching elements on the lower-side arm are switched off.

An electric power steering apparatus that driving-controls a motor via inverters based on a current command value, and applies an assist force by the motor to a steering system, includes multi-system driving systems with the inverters for respective system-windings of the motor which is a multi-system motor, wherein respective multi-system current command value characteristics against a steering torque are applied so as to be disproportionate for left and right steering, to the respective multi-system driving systems, and an assist-control is performed in response to the individual current command value characteristics.

A steering device includes a clutch and a wheel-turning shaft. The clutch includes an input shaft, an output shaft, a planetary gear mechanism, a housing, and a restriction member. The planetary gear mechanism is coupled to each of the input shaft and the output shaft. The housing is configured to accommodate the planetary gear mechanism and at least part of the output shaft. The restriction member is secured to the housing or constitutes part of the housing. The restriction member is opposed to an outer surface of the output shaft through a gap so as to restrict inclination of the output shaft. The wheel-turning shaft is configured to be displaced in accordance with rotation of the output shaft so as to turn wheels of a vehicle.

A motive power transmission mechanism includes a motor, a drive pulley, a driven pulley, a belt, a housing, and a cap. The motor includes an output shaft and a motor main body. The drive pulley is configured to rotate together with the output shaft. The belt is wound across the drive pulley and the driven pulley to transmit torque from the drive pulley to the driven pulley. The housing accommodates the drive pulley, the belt, and the driven pulley. The housing includes a work window which faces the belt and through which the belt undergoes work from outside of the housing. The cap is configured to close the work window when the work is not performed. The cap includes a porous portion having air-permeability and water-impermeability.

A clutch includes a sun gear, an internal gear, planetary gears, a carrier, a first area, a second area, and a third area. The carrier has a through hole through which an output shaft extends. The first area is disposed on an inner wall of the carrier defining the through hole. The second area is disposed on an outer surface of the output shaft and is spline-fitted to the first area. The third area is disposed at a position that is on the outer surface of the output shaft and that is closer to the input shaft than the second area is to the input shaft. The third area has a shape that makes the third area rotatable while being fitted to the first area.