chapter  4
74 Pages

Limited Slip Differentials

As noted in Chapter 1, limited slip differentials have been used in a large variety of vehicles for many decades. The invention of the concept of such mechanisms many years ago can be regarded as the first step toward developing an automatic drive that exhibits the positive properties of the differential and positively engaged driveline systems and which, to a large extent, is free of the shortcomings of these drives. Limited slip differentials, while retaining the differential effect, ensure the redistribution of the torque between the axle’s wheels, increasing the torque at the wheel with better gripping of the surface of motion upon a reduction of the torque at the wheel that is subjected to poorer gripping conditions. This also applies to the use of the mechanisms as interaxle power-dividing units: the driving axles with better gripping conditions develop a larger torque, whereas those with poorer gripping conditions develop a smaller torque. Over the last 50-70 years, many successful designs of thesemechanisms have appeared and their refinement and upgradation continue to the present day. Usually, the redistribution of torques between output shafts in limited slip differentials is

based on the use of elevated internal friction. A prolonged investigation of these mechanisms showed that, in spite of design differences, they could be investigated and designed from a common point of view. This led to the formulation of general relationships in the operation of limited slip differentials and analytic relationships of similar structures were developed for this purpose. These and other results are described in this chapter.