Transfer case with inter-axle dual-planetary differential

摘要

A dual planetary differential for a two wheel/four wheel drive vehicle transfer case mechanism providing an unequal torque split between the front and rear wheels during its full-time four wheel drive operation. The dual planetary gear set may be shifted by means of a mode clutch to provide either four wheel drive with full-time differentiation between the front and rear wheels or a part-time four wheel drive mode wherein the dual planetary is in a locked-up condition. The first and second sun gears of the dual planetary have unequal diameters with differing numbers of teeth such that, for example, proportionally more torque is transferred to the rear wheels than the front wheels. The sun gears have complementary frusto-conical web portions arranged in a juxtaposed compact manner within the transfer case.