Vehicle drive system including drive mode-shifting mechanism for shifting between two-wheel drive and four-wheel drive

摘要

A vehicle drive system includes a compact drive mode-shifting mechanism that is mounted in the final drive gearset of a vehicle. The drive mode-shifting mechanism includes a first shaft, a second shaft, and a clutch assembly. The first shaft forms an input shaft for the differential for a pair of wheels, the second shaft transmits engine power and the clutch assembly connects and disconnects the first and second shafts to one another to effect either the two-wheel-drive mode or the four-wheel-drive mode. The first shaft has an outer surface provided with a first spline, the second shaft has an outer surface provided with a second spline, and said clutch assembly includes an axially movable shifting member provided with an internal spline. The shifting member is movable between a first position in which the internal spline on the shifting member is in engagement with the first spline on the first shaft and the second spline on the second shaft to achieve the four-wheel-drive mode and a second position in which the internal spline on the shifting member is in engagement with the first spline on the first shaft and is out of engagement with the second spline on the second shaft to achieve the two-wheel-drive mode.