A motor stator mounting device includes a plastic motor housing having a cylindrical housing section for receiving the stator. Longitudinal ribs along an inside surface of the housing section are inclined to converge gradually in a distal direction, thus tending to center a stator inserted distally into the housing section. An annular stator retaining member includes a plurality of distally extending centering features. Outside surfaces of the centering features interact with an interior surface of the housing section to center the retaining member as it is inserted distally. Inside surfaces of the centering features interact with a proximal region of a previously inserted stator, such that distal insertion of the retaining member both axially positions and radially centers the stator relative to the cylindrical housing. The retaining member is secured to the housing with a series of sonic welds to positionally fix the stator inside the housing.