AXIAL-FLOW FAN Russian patent published in 2010 - IPC F04D19/00 

FIELD: engines and pumps.

SUBSTANCE: proposed fan comprises motor with impeller arranged inside barrel that has ledges on its outer surfaces and is fitted inside the housing to make cylindrical shell. Outer surface of said ledges stays in complete contact with inner spherical surface of bore made on cylindrical shell. Motor attachment element represents a groove on motor cylindrical outer surface, nearest to the shaft. Said groove accommodates split ring that rests on groove face nearby aforesaid impeller. Motor cylindrical surface section between the groove and motor end face has a nut, aligned with motor to rests on said motor end face and screwed in threaded orifice on said hub. Inclined hub ledges have their outer spherical surface most remote from impeller, while motor outer surface is arranged directly in aerodynamic part, from impeller hub to its face opposite the shaft.

EFFECT: reduced weight and operating temperature.