Patent ID: 6113353
Filing Date: 2000-09-05
Classification: F04D

Abstract:
An axial fan having a plurality of blades (2, 2, . . . ) around an outer periphery of a hub (1), wherein:a cross-sectional configuration of each of the blades (2) at an arbitrary distance from the center of the fan is set such that a blade thickness gradually increases moving away from a blade leading edge (2a) and then gradually decreases towards a blade trailing edge (2b);each blade has a pressure surface (2c) and a negative-pressure surface (2d), and the pressure surface (2c) comprises a convex surface on the leading-edge side and a concave surface on the trailing edge side, while the negative-pressure surface (2d) comprises a convex surface, wherein the pressure surface (2c) of each blade (2) has a curved surface (2g) on an outer circumferential side thereof, said curved surface formed by rounding off said pressure surface from an outer circumferential edge (2e) of the blade over a distance S, wherein if a length of a curve (X) extending from a blade's root (2f) to the blade's outer circumferential edge (2e), connecting maximum-thickness positions of the blade (2) with each other, is taken to be W.sub.0, then S/W,.sub.0 on the curve (X) falls within a range of 0.16 to 0.25; andif a length of a camber line extending from the blade leading edge (2a) to a position where the blade thickness becomes maximum is taken to be L, and the length of the camber line extending from the blade leading edge (2a) to the blade trailing edge (2b) at said arbitrary distance is taken to be L.sub.0, then L/L.sub.0 falls within a range of 0.27 to 0.35.