Patent ID: 8449268
Filing Date: 2013-05-28
Classification: F04D,H02K,Y10T

Abstract:
1. A fan comprising: a shaft; a hollow, approximately cylindrical rotor yoke connected to the shaft and arranged to rotate around the shaft as a rotation axis; a rotor magnet secured to an inner circumference of the rotor yoke; and an impeller secured to an outer circumference of the rotor yoke and arranged to rotate together with the rotor yoke to generate an air flow; wherein the impeller is provided with at least one index arranged on the impeller to provide accurate circumferential positioning of the impeller with respect to the rotor yoke; the rotor yoke is provided with at least one index arranged on the rotor yoke to provide accurate circumferential positioning of the rotor yoke with respect to the impeller; and the impeller and the rotor yoke are arranged to contact each other such that the at least one index on the impeller does not come into contact with the at least one index of the rotor yoke; wherein the impeller is hollow, and the rotor yoke is inserted into the impeller from an axial end of the impeller; the impeller includes a surface at another axial end thereof, and the surface includes an approximately circular hole at its center centered about the rotation axis; and the at least one index comprising at least one of a notch and a projection arranged on an inner edge of the surface of the impeller that defines the approximately circular hole, the notch being concave away from the rotation axis or the projection projecting toward the rotation axis.