DC BRUSHLESS AXIAL FLOW HEAT SINK FAN MOTOR

PROBLEM TO BE SOLVED: To improve the radiating characteristic by arranging a coreless stator armature opposed to a field magnet provided on an axial flow rotating blade within a recessed part having a closed inner bottom so as to take air from the upper end part and discharge the air from the opening end. SOLUTION: A bearing housing 6 has an engaging stepped part 25 for positioning an iron base plate 11 on the circumferential part. A careless stator armature 13 is formed by insulating the upper surface of the base plate 11 and providing a plurality of air-core type armature coil 12-1, 12-2 groups set in single phase current-carrying arrangement, and face-opposed to a field magnet 14 provided on a rotary blade 2 through an axial clearance, to relatively rotate it. When the rotary blade 2 is rotated, the air taken from the axial direction is efficiently circulated within the fan motor body 1 to improve the radiating characteristic. Thus, satisfactory radiating characteristic can be provided with a thin and small size.