Gearbox

The gearbox, which has specifically been developed for Visio.M, is designed as a single-speed transmission with a fixed axle gear ratio.The gearbox features a conventional axle drive and a compact spur gear differential which distributes the torque in equal parts to the wheels. In addition, a highly innovative torque vectoring unit is used to individually transfer the power to each driven wheel.

The torque vectoring unit features a superimposing gear, based on two planetary gears and two spur gear stages which are driven by an additional electric machine. Thanks to the high gear ratio of the superimposing unit, it is possible to use a very small torque vectoring motor which nonetheless realises a high torque difference at the wheels. The redistribution of the wheel torques is achieved by an interconnecting gear which actively interacts with the differential. The torque vectoring electric machine works as a driving machine if power or rather torque is transferred to the faster turning wheel, where as it works as a generator considering the opposite case. Due to the intelligent topology of the superimposing unit, the torque vectoring motor does not consume any power during straight-line driving (apart from active actuation), which is reflected in the high efficiency of the drive train. The resulting unequal driving forces at the wheels generate a yaw momentum so that the lateral dynamics can directly be controlled.

The compact design reduces weight due to the use of lightweight materials as well as analuminium housing. A gear wheel made of a steel-plastic composite is applied, which is not only lighter than conventional gears but also improves the acoustical behaviour of the gearbox. A novel parking lock is characterized by an optimal integration and can be designed in a very space-saving way.

In this research project the Institute of Machine Elements (Lehrstuhl fürMaschinenelemente) works together with AmtekTekfor.