US Patent 11022136 Fan and manufacturing method thereof

A fan includes a motor base, a bearing, an impeller, a stator and a magnetic element. The motor base has a bearing stand in a center portion thereof. The bearing is accommodated within the bearing stand. The impeller includes a metallic case, a hub, plural blades and a rotating shaft. The metallic case has a top wall and a sidewall. The hub is sheathed around the metallic case. The blades are disposed around an outer periphery of the hub. The rotating shaft is inserted into a central opening of the top wall and penetrated through the bearing stand, wherein no raised ring structure is formed in the top wall of the metallic case, and the rotating shaft and the metallic case are jointed together by a laser welding process. The magnetic element is disposed on an inner wall of the metallic case and aligned with the stator.