Vehicle gear assembly for torque transfer to two or four wheels

Abstract

A gear assembly for selectively shifting the driving torque in an engine driven vehicle to either a 2 or 4-wheel high mode while in motion, or from a neutral position to a 4-wheel low mode and return. The assembly has five main gears including an input set of two and an output set of three constant mesh gears rotatably mounted in fixed positions and a synchronizer in between the two sets in selective driving association with the output gear set. Selective transfer of torque from the input drive to the assembly to either or both the front and rear output shafts is effected by operation of a single shift rod which in turn moves a single fork both for activation of the synchronizer and for shifting the assembly into its 2 and 4-wheel high, neutral and 4-wheel low drive positions through interconnecting gear clutch collars. In one embodiment a pair of coaxial collars are incorporated in the gear assembly. In a second embodiment which reduces need for concern for windup stress, three such collars are utilized, one being coaxial with two side-by-side slideable collars internal thereof. A poppet member arrangement in the form of poppet balls or slugs provide an interlocking connection between clutch collars for their positive positioning in the drive positions manually selected by way of the shift rod.