Electric power steering apparatus
AssigneeHonda Giken Kogyo Kabushiki Kaisha
InventorsYoshiki Noro, Yoshinobu Mukai
Life of this patent
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Abstract
A controller for controlling the assist steering torque of an electric motor in an electric power steering apparatus has a relay failure detection unit for detecting ON failure which arises in a relay circuit provided between an electric motor driving circuit and a power supply; and a relay failure correction unit for decreasing the assist steering torque, at least the maximum value of the assist steering torque, of the electric motor based on a failure detection signal from the relay failure detection unit. Thereby, manual steering by a steering wheel with a heavier steering torque than the torque at the time of a normal mode becomes possible as deal at the time that ON failure arises in a relay circuit.
Claims6
An electric power steering apparatus comprising:
- (1) an electric motor for applying an assist steering torque to a steering system of a vehicle;
- (2) an electric motor driving circuit for driving the electric motor;
- (3) A steering torque sensor for detecting a steering torque of the steering system;
- (4) a controller for outputting a control signal based on a detection signal of the steering torque sensor to the electric motor driving circuit to control the assist steering torque with the electric motor;
- and
- (5) a relay circuit, which is capable of switching ON/OFF according to instructions of the controller, which is provided between the electric motor driving circuit and a power supply, wherein the controller comprises:
- (a) a relay failure detection unit for detecting ON failure in the relay circuit;
- and
- (b) a relay failure correction unit for decreasing the assist steering torque, at least the maximum value of the assist steering torque, of the electric motor based on the failure detection signal of the relay failure detection unit at the time of ON failure of the relay circuit.
Dependencies are inferred from the claim text.