Hydrostatic and synchronous shift transmission unit for arrangement between a drive motor and a consuming device

Transmission unit (1) for arrangement between a drive motor (47) and a consuming device (48), comprising a hydrostatic transmission (2), having a hydraulic motor and a hydraulic pump adjustable by means of an adjusting device (15a, 15b), a mechanical shift transmission (4), functionally arranged downstream of the hydrostatic transmission, having a plurality of gears (5, 6), and a control device for adjusting the hydrostatic transmission (2) by means of the adjusting device (15a, 15b) for a shifting process, characterised in that,

• the shift transmission (4) is a synchronous transmission with synchronization devices (7, 7a) for the gears (5, 6), in that,
• a device (U, V2) for the measuring or monitoring of the output drive torque (M) of the hydrostatic transmission (2) is associated with the control device (16), and in that,
• in the event that before a process of gear shifting the output drive torque (M) is greater than the working moment of the associated synchronization device (7, 7a) the control device (16) sets an output drive torque (M) at the hydrostatic transmission (2) by means of the adjusting device (15a, 15b), which is equal to or smaller than the working moment of the synchronization device which is associated with the relevant gear (6, 7).