This paper describes an optimization methodology dedicated to the minimization of the noise and vibrations in electric motors. It relies on a numerical workflow which is described in this paper, coupling models belonging to the fields of electromagnetics, structural dynamics and acoustics. Afterwards, a deterministic optimization method is described and applied to automotive traction motors. A robust enhancement of the optimization is then presented. It aims at considering the effect of manufacturing tolerances, materials properties dispersion and control uncertainties on the vibratory and acoustic levels to minimize, so that the electric motors are really silent when manufactured and operated. This robust optimization method is applied on a practical case.