Variable valve timing controller

A variable valve timing controller applied to a variable valve timing device provided with a motor device including a motor and a motor drive circuit for supplying power to the motor for a drive, wherein a rotational force generated by driving the motor is transmitted to a cam shaft for an internal combustion engine, and a rotational phase of the cam shaft relative to a crank shaft for the internal combustion engine is changed by the rotational force, comprising:

• a first power supply control portion for performing a first power supply control for controlling the rotational phase to a target value by driving the motor by the motor drive circuit;
• a lock detecting portion for detecting an occurrence of a lock state where a load for rotating the cam shaft temporarily increases such that the load is greater than the rotational force and a change of the rotational phase stops or substantially stops during a changing of the rotational phase to the target value by the first power supply control portion with the internal combustion engine stopped;
• a cooling control portion for cooling the motor device in a case where it is detected that the lock state occurs by the lock detecting portion;
• and
• a second power supply control portion for performing a second power supply control for eliminating the lock state by driving the motor by the motor drive circuit after cooling the motor device by the cooling control portion,
• wherein:
• the second power supply control portion is configured to perform, as the second power supply control, 1) a reverse rotational control for temporarily controlling the rotational phase in a direction opposing a changing direction to the target value such that a rotational direction of the cam shaft is reversed from a forward direction to a reverse direction after detection of the lock state, and 2) a subsequent switching of the rotational direction back to the forward direction by temporarily increasing a power supply amount to the motor to a predetermined increasing amount at a start of switching the rotational direction.