Patent ID: 7956564

Claim:
A valve timing adjusting apparatus for an internal combustion engine, which adjusts valve timing of at least one of intake and exhaust valves of the engine that are opened and closed by a camshaft driven by torque transmitted from a crankshaft of the engine, the valve timing adjusting apparatus comprising: an electric motor including a plurality of stator windings, which create a magnetic field upon being energized, and a motor shaft that is caused by the magnetic field to rotate in one of a normal direction and a reverse direction, the motor shaft having a plurality of predetermined rotation angle ranges; a plurality of switching elements each of which is electrically connected to a corresponding one of the stator windings; a motor driver that drives the electric motor by selecting, for each of the rotation angle ranges of the motor shaft, one of the switching elements and turning on the selected switching element in the rotation angle range; and a phase adjusting mechanism that adjusts a relative phase of the camshaft to the crankshaft according to a rotational condition of the motor shaft; wherein when a target rotational direction of the motor shaft is coincident with the actual rotational direction of the motor shaft, the motor driver continuously turns on the selected switching element for the whole of the rotation angle range, and when the target rotational direction of the motor shaft is opposite to the actual rotational direction of the motor shaft, the motor driver continuously turns on the selected switching element only for part of the rotation angle range, and continuously turns off the selected switching element for the remaining part of the rotation angle range.