Patent ID: 6484857
Filing Date: 2002-11-26
Classification: B60K,Y10T

Abstract:
A power transfer system for a motor vehicle having an engine and first and second sets of wheels, comprising:a transfer mechanism for transmitting drive torque from the engine to the first set of wheels and selectively transmitting drive torque to the second set of wheels through a transfer clutch capable of varying the torque transmitted therethrough by varying a clutch engagement force; an apply plate that is movable relative to said transfer clutch between a first position for generating a minimum clutch engagement force and a second position for generating maximum clutch engagement force; a ball screw actuator having an electric motor, a lead screw and a plurality of balls, said electric motor having an output shaft with a helical groove formed on an outer surface of said output shaft, said lead screw having an internal circumferential surface and a helical groove formed thereon, said plurality of balls being positioned within said helical grooves between said output shaft and said lead screw wherein rotation of said output shaft axially displaces said lead screw to act on said apply plate for producing a linearly directed output force in response to control signals, said linearly directed output force being exerted on said apply plate to move said apply plate between its first and second positions; and a controller for generating said control signals.