Patent ID: 8280589

Claim:
A steering apparatus comprising: a primary power supply apparatus; a secondary power supply apparatus charged by the primary power supply apparatus; an electric actuator which generates a steering force for steering wheels; a drive circuit which receives electric power from a drive system power supply circuit formed by connecting the primary power supply apparatus and the secondary power supply apparatus in parallel and which drives the electric actuator; an electronic control apparatus which receives electric power from a control system power supply circuit connected to the primary power supply apparatus and which outputs a control signal to the drive circuit so as to control operation of the electric actuator; a secondary control system power supply circuit which is connected to the secondary power supply apparatus and the electronic control apparatus and supplies electric power from the secondary power supply apparatus to the electronic control apparatus; power-supply-capacity-drop detection means for detecting a drop in the power supply capacity of the primary power supply apparatus and a drop in the power supply capacity of the secondary power supply apparatus; and power supply control means, operable when both a drop in the power supply capacity of the primary power supply apparatus and a drop in the power supply capacity of the secondary power supply apparatus are detected, for giving priority to the supply of electric power from the secondary power supply apparatus to the electronic control apparatus over the supply of electric power from the secondary power supply apparatus to the drive circuit.