| 摘要 |
PROBLEM TO BE SOLVED: To provide a power steering system that can protect an electric motor against overheat without sacrificing a steering feeling at sudden steering. SOLUTION: A basic target rotational speed setting part 42 sets a basic target rotational speed Rb of the electric motor 27 according to a vehicle speed and a steering angular velocity. A temperature coefficient setting part 43 sets a temperature coefficient a reducing with increasing temperature. A target rotational speed setting part 44 sets a target rotational speed R of the electric motor 27 from R=α.Rb. A motor drive control part 45 controls a driving circuit 28 so that the target rotational speed R is reached. Upon a temperature rise in the electric motor 27, steering auxiliary effort is reduced over a full range of steering angular velocity. |
