Patent ID: 7245056

Claim:
An axial fan motor for a cooling unit, adapted to air-cool a heat sink of a heat generating device, said axial fan motor being disposed on one side of said heat sink, opposite said heating element, and adapted to feed cooling air into the interior of said heat sink, said axial fan motor comprising: a rotor and a plurality of fan blades attached to an outer circumferential surface of the rotor; a casing surrounding said rotor and blades and defining a flow passage for flow of cooling air between said rotor and said casing and for directing the cooling air into the heat sink; a bearing holder on which a stator of said motor, disposed inside said rotor, is fixed, said bearing holder supporting a rotary shaft of said motor via a bearing and connecting said stator to said casing, said rotor being fixed to said rotary shaft, wherein: said casing is formed of a plurality of metal plates laminated along the axial direction of said rotary shaft, said plurality of metal plates comprising: a single first metal plate, which is an outermost metal plate of said casing and which is located at an air exhaust side, said first metal plate including a peripheral portion having a circular inner edge, a center portion having a circular outer edge, and a plurality of arm portions connecting the peripheral portion and the central portion, said bearing holder being attached to the central portion; and a plurality of large and small second metal plates extending outwardly from circular inner edges to peripheral edges, wherein the large second metal plates alternate in series with the small second metal plates, and wherein peripheral edge portions of the large second metal plates project beyond the peripheral edges of the small second metal plates, whereby the large and small second metal plates define a peripheral surface with fins for the casing.