VALVE TIMING CONTROL APPARATUS

PROBLEM TO BE SOLVED: To provide a valve timing control apparatus that ensures both of proper valve timing and prevention of thermal damages. SOLUTION: Under a configuration that an engine phase for determining a valve timing is controlled depending on a rotational status of a motor shaft 102 of an electric motor 4, if an actual rotation direction Dr and a target rotation direction Dt of the motor shaft 102 coincide with each other, an electric power supply driver 78 supplies power to a stator coil 109 of the electric motor 4 by executing duty control of turning ON and OFF of selection elements GU, GV, GW selected as switching elements of ON target. If the actual rotation direction Dr and the target rotation direction Dt do not coincide with each other, the electric power supply driver 78 sets an on-duty ratio of the selection elements GU, GV, GW by the duty control below a lower limit value for rotating the motor shaft 102 through the power supply to the stator coil 109. COPYRIGHT: (C)2009,JPO&INPIT