Drive system for motor vehicles having driven front and rear axles

摘要

A drive system for motor vehicles having driven front and rear axles comprises a liquid friction coupling, which is incorporated in the rear axle drive train, and a clutch, particularly an overrunning clutch, which is connected in series with said liquid friction coupling and arranged to be released in response to a front axle speed exceeding the rear axle speed. In order to avoid a requirement for stronger steering forces during a reverse travel and to avoid an operation of the liquid friction coupling with mixed friction, that second clutch is arranged to be automatically engaged in dependence on the liquid temperature in the liquid friction coupling or of other variables.