20110309705 | MOTOR ROTOR AND A MOTOR HAVING THE SAME - A motor rotor includes an annular body and a plurality of magnetic bodies installed on an inner lateral surface of the annular body in an irregular manner, to prevent a rotating motor from generating a cogging effect, disperse the frequency of the cogging torque, and reduce the amplitude. Accordingly, noises generated while the motor is operating are reduced, the periodicity of a cogging torque is changed, and cogging torque is reduced. | 12-22-2011 |