Patent ID: 7123483

Claim:
A heat sink fan for cooling a heat generating electrical component, comprising: a heat sink including a base portion with a central axis and a plurality of circumferentially adjacent heat radiating fins integrally or fixedly formed on the side surface of the base portion, each of the heat radiating fins extending away from the central axis and having at least one radially distal edge; a fan motor unit including an axial flow fan having a rotational axis, a housing unit connected fixedly with the axial flow fan, the housing unit including a housing and at least one arm portion; wherein the fan motor unit is arranged by the housing unit, with the rotational axis substantially corresponding to the central axis, on a first end side of the heat sink, for supplying cooling air to the heat sink; the arm portion extends from the housing towards a second end side of the heat sink; an engaging portion is formed at a tip of the arm portion; and at least one circumferentially partial engagement feature is formed along an envelope of the heat sink by distal-edge protrusions or recesses in a group of several, but not all, adjacent heat radiating fins, for engagement with the engaging portion of the arm portion so that the fan motor unit when attached to the heat sink is restricted in relative movement in the axial direction.