WIPER MOTOR

PROBLEM TO BE SOLVED: To provide an electric motor for wiper devices wherein it is possible to ensure an output torque in a low current range and reduce an output torque in a high current range. SOLUTION: The wiper motor drives a wiper device that wipes the windshield of a vehicle. In the wiper motor, auxiliary poles 47 that are formed of a magnetic material and suppress the output torque in a high current range are set between magnets 22 fixed on the inner surface of a motor yoke 21. Provision of the auxiliary poles 47 between the magnets 22 increases the inductance of armature winding and this increases the counteraction of an armature. In a high current range, an increase in inductance has great influence and the output torque is largely reduced. Meanwhile, in proximity to an operating point, the current value is low, so that the counteraction of the armature has light influence and output torque substantially equivalent to that without auxiliary poles is obtained. As a result, it is possible to ensure the torque in proximity to the operating point (low current range) and reduce the torque in a high current range. COPYRIGHT: (C)2010,JPO&INPIT