A steering system includes a steered shaft, a ball screw nut, balls, a housing, a rolling bearing, and a snap ring configured to prevent the rolling bearing from detaching from the ball screw nut. The rolling bearing includes double-row rolling element arrays, an outer ring, a first inner ring, and a second inner ring. The ball screw nut has a receiving portion. The snap ring contacts a side face of the second inner ring to push the second inner ring toward the receiving portion via the first inner ring. A resistance force received from the second outer peripheral fitting surface when the second inner ring moves in the axial direction in a state in which detachment of the rolling bearing is not prevented by the snap ring is smaller than a pushing force with which the snap ring pushes the second inner ring.

A steering control device includes a first control system and a second control system. The first control system includes and a first microcomputer. The first microcomputer is configured to compute a first command value for controlling power supply to a first coil and a second command value for controlling power supply to a second coil. The second control system includes and a second microcomputer. The second microcomputer is configured to compute the first command value and the second command value. The first microcomputer and the second microcomputer are configured to communicate the first command value and the second command value with each other. The cycle of communication between the first microcomputer and the second microcomputer is set to be equal to or shorter than each of the cycles of computations of the first command value and the second command value by the first microcomputer and the second microcomputer.

Technical solutions are described for controlling operation of an electric machine such as a permanent magnet synchronous motor (PMSM) drive or motor control system to protect against excessive machine current or voltage in a PMSM drive. Systems and methods employ a torque control algorithm for PMSMs that uses the constraints of both machine current and voltage capability in PMSM drives, and online torque command modification according to the maximum allowed torque under these machine current and voltage constraints.

A device includes a first assist shaft having a first axially extending bore, the first assist shaft engaging, via the first axially extending bore, a first end of a torsion bar. The device may include a flux carrier engaged on an end of the first assist shaft proximate the torsion bar. The device may include a second assist shaft having a second axially extending bore, the second assist shaft engaging, via the second axially extending bore, a second end of the torsion bar and connected to the first assist shaft by the torsion bar. The device may include a permanent magnet ring having an inner circumference that receives an outer circumference of the second assist shaft and the permanent magnet ring disposed in a third axially extending bore of the flux carrier. The device may include a magnetic flux sensor at least partially disposed in the flux carrier.

A power steering assembly includes an electric motor having an output shaft extending therefrom. The assembly also includes a housing containing a worm gear operatively coupled to a steering shaft, the worm gear rotatable about a worm gear axis. The assembly further includes an electric motor and a worm arranged to engage the worm gear, the worm extending from the output shaft of the electric motor as a single, integrally formed shaft, the single, integrally formed shaft extending axially from a first end to a second end and being cantilevered to allow the second end to deflect. The assembly yet further includes a bushing surrounding a portion of the shaft proximate the second end of the shaft, the bushing and the portion of the shaft defining a clearance therebetween.

A position measurement system for a steering system includes a steering shaft. The position measurement system also includes a worm gear coupled to the steering shaft. The position measurement system further includes a worm in meshed engagement with the worm gear, the worm driven by a motor. The position measurement system yet further includes a first sensor operatively coupled to the worm to detect an angular position of the worm and the motor that drives the worm. The position measurement system also includes a driving gear coupled to the steering shaft. The position measurement system further includes a spur gear in meshed engagement with the driving gear. The position measurement system yet further includes a second sensor operatively coupled to the spur gear to detect an angular position of the spur gear.

A method for controlling an assist motor of a power steering system, power steering system including the assist motor configured to apply a motor torque on a rack, and at least one steering computer, method being designed to servo-control a position of the rack to a position setpoint, method including: a maneuvering step in which the assist motor exerts a motor torque on the rack according to a motor torque setpoint; wherein the method also includes: servo-control step in which the steering computer determines a speed setpoint of the rack according to the position setpoint and to the position of the rack; limitation step in which the steering computer issues a limited speed setpoint which is lower than or equal to a maximum speed threshold; control step in which the steering computer determines the motor torque setpoint according to the limited speed setpoint and to a speed of the rack.

A method for controlling a power steering system of a vehicle which is intended to limit the physical supply current supplied to the at least one power steering motor in the event of an impact between at least one rack and at least one mechanical end stop, the control method including: —a determination step wherein the power steering computer determines a setpoint torque for the power steering motor; —a driving step wherein the power steering computer determines the setpoint supply current for the power steering motor; wherein the control method also includes: —a detection step wherein the power steering computer detects an impact between rack and mechanical end stop; —a protection step emitting a protected signal to the driving step when an impact is detected, so that the setpoint supply current determined by the driving step is below a maximum setpoint supply current.

A method of steering steerable wheels of a vehicle includes determining a first angle of a first portion of a steering column. A second angle of a second portion of the steering column is determined. The first and second angles are compared to determine a difference between the first and second angles. The vehicle is steered autonomously if the difference between the first and second angles is above a predetermined amount and a time that the difference between the first and second angles is above the predetermined amount is greater than a predetermined amount of time.

A method of steering steerable wheels of a vehicle includes determining a first angle of a first portion of a steering column. A second angle of a second portion of the steering column is determined. The first and second angles are compared to determine a difference between the first and second angles. The vehicle is steered autonomously if the difference between the first and second angles is above a predetermined amount and a time that the difference between the first and second angles is above the predetermined amount is greater than a predetermined amount of time.