Classification and analysis of lateral torque-vectoring differentials using velocity diagrams

Abstract

This paper describes the classification and analysis of lateral torque-vectoring differentials using velocity diagrams, which are frequently used for the gear-shifting analysis of an automatic transmission. A lateral torque-vectoring differential is composed of the mechanism of torque vectoring from the right wheel to the left wheel, and the similar mechanism of torque vectoring from the left to the right. The analysis shows that, when only the mechanism part of one-way torque vectoring is considered, then the smallest number of the rotational elements composing the one-way torque-vectoring mechanism is four. This is the simplest mechanism. The mechanism is classified into seven kinds of mechanism, namely six clutch-type mechanisms and one brake-type mechanism. The expressions for the clutch torque for torque vectoring, the clutch slip speed, and the energy loss generated by clutch are presented for these mechanisms. As a result, the theoretical value of energy loss is completely the same in these seven kinds of mechanism in the ideal state, in which the transmission efficiency of gears, agitation loss, etc., are assumed to be neglected. Finally, from an actual mechanism design point of view, the best mechanism is evaluated.