Abstract: Axial fan compact bearing viscous pump having two spaced apart bearing housings and a bearing supported within each bearing housing. A shaft is supported within each bearing housing. The shaft has two oil disks, each bearing having an oil disk proximate thereto. The portion of each bearing housing fitting about a respective one of the oil disks forms a viscous pump housing. The viscous pump housing has an oil inlet and an oil outlet. The oil outlet is spaced from the oil inlet. On an inner periphery of the viscous pump housing, an oil channel in an inner periphery facing an outer periphery of the one of the oil disks extends only partway around the viscous pump housing inner periphery. The oil channel extends from the oil inlet in the direction of rotation of the shaft to a point beyond the oil outlet.

Abstract: In accordance with the present invention, there is provided a simple solution to retain the vortex in the confined position, within the fan, thereby permitting higher operational fan speeds a lower energy consumption. By using the false-bottom, which eliminates at least one vertex of the rear wall of the inlet chamber, an aerodynamic and structural asymmetry is introduced at the bottom of the inlet box, near the impeller inlet, that is sufficient to retain the impeller vortex totally within the impeller and inlet cone, and prevent its expansion into the inlet box proper, while still permitting the pre-spin effects of the parallel bladed inlet dampers at reduced load conditions.