Patent attributes
A brushless DC motor has a stator and a rotor. An angle θ0 between an edge section of the flux barrier on a magnetic pole center side and an edge section on a side for coming in contact with the rib of adjacent flux barrier, with respect to the rotor center, is determined to be equal to or greater than an angle satisfying a following relationshipθ0=180°*m/(Pn*f/f0) (provided 2θ0−θr<90°)wherein, a frequency of vibration which is to be reduced is represented with f, a pole pair number is represented with Pn, an electrical frequency is represented with f0=Pn*N, a motor revolution is represented with N, m=1, 3, 5, . . . , an angle of the rib with respect to the rotor center is represented with θr, therefore making of motor highly effective and decreasing of the motor acoustic noise are coped with.
