Viscous coupling apparatus for on-demand four wheel drive system

摘要

A viscous fluid rear axle coupling apparatus for a front engine vehicle having a front transaxle drivingly interconnected to its front pair of wheels. The viscous coupling apparatus includes power transfer means adapted to convert the rotation of the vehicle's longitudinal propeller shaft into rotation of an outer drum of the apparatus about a transverse axis. The outer drum concentrically surrounds a pair of coaxial right and left inner drums enclosed in a housing chamber filled with viscous fluid. Each inner drum is drivingly connected to respective right and left rear wheel output shafts extending transversely outboard therefrom. Each inner drum has a set of inner plates interleaved with a single set of outer plates of the outer drum. The apparatus functions as an interaxle and limited slip differential during four wheel drive as well as a conventional differential allowing the rear wheels to rotate different amounts during its two wheel and on-demand four wheel drive modes.