| 摘要 |
PROBLEM TO BE SOLVED: To reduce noise emission and enhance air blowing efficiency. SOLUTION: A peripheral edge 3 of a hub 2 is formed in rotational symmetry of approx. an triangle whose projecting ends 2A are rounded in such a constitution that arc-shaped edge portions 4 having a small curvature with the radius of curvature twice or more of the radius of the circumscribing circle 9 and arc-shaped edge portions 5 having a large curvature with the radius of curvature no larger than the radius of the circumscribing circle 9 of the hub 2 are provided alternately in continuity, and in the part of the edge portion 4 between the projecting ends 2A, a vane 1 is installed in eccentricity toward the side of hub rotation.
|
