ROTOR FOR BRUSHLESS DC MOTOR

摘要

PURPOSE: A rotor of brushless DC motor used by a washing machine is provided to reduce the vibration and noise by decreasing the density of magnetic flux at the boundary point of the rotor pole. CONSTITUTION: An edge(11) is cut off of the rotor toward the shaft direction, which cut dimension is within 2.5-25 electrical angle so air gap of the cut area is increased. According the big air gap, the reluctance is increased and the density of the magnetic flux is decreased when magnetizing the permanent magnet of the yoke. Then the vibration and noise caused by the cogging torque are reduced. When driving the motor with weak magnetic field, the current for spin dry is reduced because of improved torque and acceleration caused by reduced reverse electromotive force in the operation region of the weak magnetic field.