| 摘要 |
PROBLEM TO BE SOLVED: To provide an axial flow fan in which surface coarseness of an impeller is controlled individually on a positive pressure surface and a negative pressure surface, and thereby reducing generation of noise, improving P-Q (static pressure-air volume) characteristics and further reducing power consumption.SOLUTION: An axial flow fan 1 comprises a motor driving part 2 and an impeller 3 which is rotated by the motor driving part 2, and surface coarseness on a positive pressure surface 5 of the impeller 3 is increased more than surface coarseness on a negative pressure surface 4 of the impeller 3. The positive pressure surface 5 of the impeller 3 and the negative pressure surface 4 of the impeller 3 have a round coarse shape that can be specified by a curvature radius in a microscopic manner. |
