Multiple-ratio hydrostatic-mechanical split-torque powershift transmission

Power-shift transmission with hydrostatically split actuating mechanism (HG), a two-stage planetary gear unit (T, II), a mechanical 8-speed gearbox which can be operated in forward and reverse mode, and a control device (ST) which controls the clutches (VV, VR, VO - V8) of the mechanical gearbox in such a way that, for starting, the actuating mechanism (HG) is connected to the output shaft (ASW) without torque division and the clutches are in each case shifted under no load and synchronisation of the countershaft (ZW) is only carried out when shifting up into 6 gear via clutch (K5) and when shifting down into the 4 gear via the clutch (K4) for the 4 gear. Starting and reversing is hydrostatic; efficiency is high; the mechanical gearing factor is approximately 60; synchronisation wear is low and there are only two synchronisation clutches (K4, K5). In a second specifiable operating mode, the mechanical gearbox is controlled without synchronisation as a 4-speed gearbox with hydrostatic starting and reversing range.