Differential Locks with Regulating Effect
Controllable differential locks enable an adjustment of the frictional torque. This can take place by a stepped or continuously variable approach. The multi-disk clutch, which can be controlled using the vertical pressure, can be used as a friction element.
In the layout of such differential locks, it has however to be considered that the locking torque always remains smaller than the difference in transferable traction forces. At the most, a wheel can spin (the corresponding is applicable to driven axles when a differential lock is used on a transfer case).
If the instantaneous frictional torque of axle differential lock is larger than the difference of the friction potentials at the left and right wheel of an axle, both wheels could spin at a correspondingly high input torque: the vehicle then would be difficult to control.
A continuously variable control of the frictional torque, based on the utilisable friction potential or driving condition, can take place using electronics. The possible input data include wheel speeds, wheel loads, steering angle, and transverse acceleration. The hence resulting locking torque, dependent on the driving situation, leads to optimum traction with simultaneously high driving stability. The figure shows an example for a hydraulically controlled automatic differential lock.