Abstract: An exemplary heat dissipation fan includes a rotor and a stator. The rotor includes a hub, a central shaft extending down from a top end of the hub, the shaft having a free end far from the top end of the hub. A magnetic element attached to an inner periphery of the hub. The stator includes a stator core consisting layers of yokes, two insulation frames mounted at two opposite ends of the stator core and a coil wound around the insulation frames. An outer surface of the stator faces and is spaced from an inner surface of the magnetic element of the rotor with a clearance defined therebetween. A width of a bottom end of the clearance adjacent to the free end of the shaft being smaller than a width of a top end of the clearance.

Abstract: A cooling fan includes a fan housing and a rotor received in the fan housing. The fan housing has an air inlet and an outlet opposite to the air inlet. The rotor includes a shaft, a hub engaged with the shaft, and a plurality of rotary blades extending outwardly from the hub. The hub has an outer surface expanding along a direction parallel to a central axis of the shaft from the air inlet to the air outlet.

Abstract: An exemplary heat dissipation fan includes a rotor and a stator. The rotor includes a hub, a central shaft extending down from a top end of the hub, the shaft having a free end far from the top end of the hub. A magnetic element attached to an inner periphery of the hub. The stator includes a stator core consisting layers of yokes, two insulation frames mounted at two opposite ends of the stator core and a coil wound around the insulation frames. An outer surface of the stator faces and is spaced from an inner surface of the magnetic element of the rotor with a clearance defined therebetween. A width of a bottom end of the clearance adjacent to the free end of the shaft being smaller than a width of a top end of the clearance.