Patent ID: 6530748
Filing Date: 2003-03-11
Classification: F04D,F05D,F16D

Abstract:
A fan drive assembly of the type comprising a cooling fan attached to a fluid coupling device, said cooling fan comprising a fan hub, a spider portion and a plurality of fan blades extending radially from said fan hub, said fluid coupling device comprising a rotatable coupling assembly including a body member having a rearward surface, and a cover member cooperating with said body member to define a fluid chamber therebetween, a rotatable coupling member disposed in said fluid chamber for rotation relative to said coupling assembly; said coupling assembly and said coupling member cooperating to define a viscous shear chamber therebetween, whereby torque may be transmitted from said coupling member to said coupling assembly in response to the presence of viscous fluid in said viscous shear chamber; said body member including a plurality of cooling fins and a plurality of mounting portions, said spider portion being attached to said mounting portions and defining a pilot diameter; characterized by:(a) said body member including only three of said mounting portions, each of which is disposed immediately adjacent an outer periphery of said body member; (b) each of said mounting portions including a spider mounting surface on a rearward face thereof, said spider mounting surface including a radially disposed pilot surface in engagement with said pilot diameter of said spider portion; (c) said plurality of cooling fins covering substantially all of said rearward surface of said body member not covered by said mounting portions; and (d) said body member defining an outside diameter, and said spider portion pilot diameter defining a diameter which is from about 53% to 83% of said outside diameter.