An All Wheel Drive System Utilizing Twin Hydraulic Couplings with Gerodisc System

Hydraulically actuated, friction disc type couplings are capable of being utilized as direct drive limited slip devices for use on auxiliary drive axles. These couplings can be excited to function at wheel speed Δn levels due to their high torque transfer density and high torque transfer capacity.

The utilization of these hydraulic couplings eliminates the need for torque multiplication through speed reduction. The common differential element is replaced by two independent, but communicating couplings to facilitate direct drive of the wheels on the auxiliary axle.

The arrangement described in this paper provides a built in limited slip differential (LSD) effect as well as a simple and powerful all wheel drive (AWD) system. This paper will compare the performances of such systems with classic architectures under various driving conditions.