Patent ID: 8690547

Claim:
A fan comprising: a stator unit; and a rotor unit rotatable about a center axis, the rotor unit including: a yoke made of metal and having a substantially hollow cylindrical shape centering on the center axis; and an impeller portion made of resin and including a connecting portion and a plurality of blades arranged around the center axis on the connecting portion, the connecting portion being fixed to the yoke by being fastened to a flange portion of the yoke which extends in a radially outward direction from the center axis; wherein the connecting portion of the impeller portion is arranged to cover both of axial surfaces of the flange portion of the yoke and at least one radial surface of the flange portion of the yoke, the connecting portion including both an upper fixing portion arranged at a position axially above the flange portion of the yoke to cover an axially upper portion of the flange portion of the yoke and a lower fixing portion arranged at a position axially below the flange portion of the yoke to cover an axially lower portion of the flange portion of the yoke such that the flange portion of the yoke is sandwiched between the upper fixing portion and the lower fixing portion, the axially lower portion including a portion of an axially lowermost surface of the yoke; the yoke includes an innate surface which is a portion of an outer side surface of the yoke not covered by the connecting portion; the impeller portion intakes air from a direction along the center axis, and exhausts air into a direction away from the center axis; a magnet is fixed to a surface of the yoke such that the magnet is in direct surface-to-surface contact with an inner surface of the yoke; and the connecting portion includes a plurality of bottom affixing portions arranged to be spaced apart in a circumferential direction of the rotor unit.