Dynamic range shift transfer case has electromagnetic modulating friction clutch

摘要

A two speed transfer case (10) includes a spring biased dog clutch (40) connecting a shift sleeve (22) to a main input shaft (32) and an electromagnetic friction clutch (42) for transferring torque from the shift sleeve (22) to one of the outputs (67, 70). This arrangement allows dynamic upshifts and downshifts and modulation of the torque split between the outputs. The shift sleeve (22) is preferably moved electrically via a shift rod 96 and worm gear 98 in response to driver operation of a switch. The electromagnetic friction clutch may be automatically controlled in response to differences in the output speeds to control the torque split.