Patent ID: 8209079
Filing Date: 2012-06-26
Classification: B62D

Abstract:
1. An electric power steering system comprising: an electric motor that generates output power for assisting steering operation of a steering wheel; a torque sensor for generating electric output signals corresponding to toque applied to the steering wheel; and a control unit for controlling an operation of the electric motor in accordance with the electric output signals of the torque sensor, wherein the torque sensor includes a magnetic flux generating part and a plurality of output generating parts, the magnetic flux generating part generating magnetic flux varying with a steering operation of the steering wheel, and the plurality of output generating parts generating the electric output signals in accordance with the magnetic flux generated by the magnetic flux generating part and a supply voltage supplied from a predetermined electric power supply circuit, and wherein the control unit includes a failure checking part, a voltage varying part and a failing device specifying part, the failure checking part checking whether any one of the plurality of output generating parts has a failure, the voltage varying part temporarily varying the supply voltage if the failure in any one of the output generating parts is determined, and the failing device specifying part specifying failing one of the plurality of output generating parts as a failing device by determining, when the supply voltage is temporarily varied, that the output generating part is normal and is in failure when the electric output signal thereof varies and does not vary temporarily in correspondence to temporary variation of the supply voltage, respectively.