| 摘要 |
PROBLEM TO BE SOLVED: To cool a circuit board by adopting an outer rotor type motor structure and utilizing an air flow generated by an impeller.SOLUTION: A centrifugal fan 1A has a motor holder 51A fixed to a mounting plate 25A. The motor holder has plural columns 511A, a plate-like section 512A, an exhaust port 514A, and a window section 515A. The plural columns extend in an axial direction outside a rotor holder 32A and a circuit board 24A in a radial direction. The plate-like section is enlarged outward in the radial direction from upper ends of the columns. The exhaust port is positioned below an impeller, and penetrates through at least one portion of the plate-like section in the axial direction. The window section penetrates in the radial direction above the mounting plate and between the adjacent columns. Gas accelerated by rotating the impeller flows downward through the exhaust port. Also, one portion of the gas passes through the window section of the motor holder, and collides with the circuit board. |
