Axial flow fan

A fan comprising:

• a motor part arranged to rotate about a center axis extending up and down;
• an impeller including a plurality of blades extending radially outward, the impeller fixed to the motor part;
• a housing arranged to surround outer peripheries of the motor part and the impeller, the housing including a cylindrical inner circumferential surface and a cylindrical outer circumferential surface;
• a first circuit board positioned radially outward of the outer circumferential surface of the housing and electrically connected to the motor part;
• and
• a plurality of ribs arranged to interconnect the motor part and the housing,
• wherein the motor part includes an armature having coils, and a second circuit board electrically connected to the coils and the first circuit board,
• the housing includes an intake port which is an upper opening of the housing, an upper edge which surrounds the intake port, an exhaust port which is a lower opening of the housing, a lower edge which surrounds the exhaust port, a flange portion enlarged radially outward from the outer circumferential surface of the housing, and a circuit board fixing portion protruding from the outer circumferential surface of the housing and making contact with the first circuit board, and
• the first circuit board is mounted with a plurality of electronic components and is disposed in a spaced apart relationship with the outer circumferential surface of the housing, the first circuit board being positioned radially inward of a radial outer edge of the flange portion and arranged to extend in an axial direction.