Patent ID: 7541702

Claim:
A brushless axial flow fan motor, comprising: a rotor including: a rotor cover including a cylindrical portion and an end plate portion integrally disposed at one end of the cylindrical portion and fixed to a rotary shaft; and a plurality of permanent magnet magnetic pole portions disposed on an inner circumferential surface of the cylindrical portion; a stator disposed inside the rotor; and an impeller including a plurality of blades and a cap member onto which the blades are mounted, the cap member being fitted with the rotor cover; the cap member including a cylindrical peripheral wall portion having an outer peripheral portion onto which the blades are mounted, and a bottom wall portion disposed at one end of the peripheral wall portion and facing the end plate portion; wherein a center through hole is formed in a center of the bottom wall portion of the cap member, the center through hole piercing the bottom wall portion in an axial direction of the rotary shaft; a plurality of vane portions are formed on an inner wall portion of the bottom wall portion, which faces the end plate portion, at equidistant intervals in a circumferential direction of the peripheral wall portion, the vane portions being shaped to draw in ambient air through the center through hole; and a plurality of through holes are formed in the end plate portion at equidistant intervals in the circumferential direction so as to introduce the ambient air, which has been drawn in via the center through hole, inside the rotor cover, the through holes piercing the end plate portion in the axial direction, wherein the number of the vane portions is larger than the number of the through holes so that the vane portions do not face the through holes.