Patent ID: 6911636

Claim:
A cooling fan for a microwave oven, arranged behind a magnetron and a high voltage transformer for applying a high voltage to the magnetron, which are disposed up and down in a electric device chamber defined in a cabinet, and adapted for directing airflow toward the magnetron and high voltage transformer, the cooling fan comprising: an axial flow fan having a ratio of an outer diameter of the fan to a width of the electric device chamber defined in the cabinet, of no less than 0.8, and wherein two adjoining blades are separated from each other by a first distance of 6˜8 mm at their blade roots, a second distance of 23˜25 mm at their blade tips, a third distance of 11˜13 mm at points which correspond to 0.75 of a length between the blade tip and the blade root when measured from the blade roots, and a fourth distance of 8˜10 mm at points which correspond to 0.95 of the length between the blade tip and the blade root when measured from the blade roots.