| 摘要 |
PROBLEM TO BE SOLVED: To effectively restrict separation of air flow, enhance blowing performance, and reduce blowing noise by, in an axial-flow fan with a plurality of blades provided in a prescribed arrangement around a boss portion, forming a plurality of grooves that run to cross the direction of air flow on a leading edge portion and periphery portion, or part of the same, on a negative pressure side of each blade. SOLUTION: An axial-flow fan 1 comprises a boss portion 2, to which a rotary shaft of a drive motor is secured, and a plurality of blades integrally mounted on the outer periphery surface of the boss portion 2. A plurality of ribs 4 are formed on a leading edge portion 3b and a periphery portion 3c on a negative pressure side 3a of each of the blades in the axial-flow fan 1. These ribs extend in a direction that crosses the air flow as indicated by a broad-line arrow. When the axial-flow fan 1 turns, there are two main streams of air flow as shown by broad-line arrows, one that goes from the leading edge portion 3b to a trailing edge portion 3d of each blade 3 and the other that goes from the periphery portion 3c to the trailing edge portion 3d of each blade 3. The plurality of ribs 4 promote transition of these air streams from a laminar flow to a turbulent flow, thereby improving blowing performance and reducing blowing noise.
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