US Patent 6994523 Air blower apparatus having blades with outer peripheral bends

An air blower apparatus is provided including a hub which is a center of rotation, and a plurality of blades disposed along an outer peripheral surface of the hub and having leading and trailing edges and where both an outer peripheral end of the leading edge and an outer peripheral end of the trailing edge lie ahead relative to the rotative direction. An outer peripheral part of the blade may be bent toward the suction side in such a way as to form a starting point at which an airflow starts leaking, and the radial-direction width, W, of the bent part gradually increases from the vicinity of the leading edge to the vicinity of the trailing edge. A blade tip vortex (β) generated from a blade positioned ahead relative to the rotational direction F and a separation vortex from a pressure surface of a blade positioned behind relative to the rotational direction F offset each other, so that discharge vortexes are suppressed.