Abstract: A drive assembly for vehicles with front wheels and rear wheels, especially for tractors, agricultural machinery, construction machinery or for self-driving machines, has an engine (1), a first drive (15) to drive the rear wheels, a second drive (27) to drive the front wheels, an adjustable hydraulic pump (5) driven by the engine (1), and an adjustable first hydraulic motor (9). The first hydraulic motor (9), with respect to drive, is connected to the first drive (15) to drive the rear wheels. Also, the first hydraulic motor, with respect to drive, may be connected to the second drive (27), to drive the front wheels. A second hydraulic motor (10), with respect to drive, can be connected to the second drive (27) to drive the front wheels. The first hydraulic motor (9) has a high coefficient of efficiency within a first driving speed range of the vehicle. The second hydraulic motor (10) has a high coefficient of efficiency within a second driving speed range of the vehicle.

Abstract: A drive assembly for vehicles with front wheels and rear wheels, especially for tractors, agricultural machinery, construction machinery or for self-driving machines, has an engine (1), a first drive (15) to drive the rear wheels, a second drive (27) to drive the front wheels, an adjustable hydraulic pump (5) driven by the engine (1), and an adjustable first hydraulic motor (9). The first hydraulic motor (9), with respect to drive, is connected to the first drive (15) to drive the rear wheels. Also, the first hydraulic motor, with respect to drive, may be connected to the second drive (27), to drive the front wheels. A second hydraulic motor (10), with respect to drive, can be connected to the second drive (27) to drive the front wheels. The first hydraulic motor (9) has a high coefficient of efficiency within a first driving speed range of the vehicle. The second hydraulic motor (10) has a high coefficient of efficiency within a second driving speed range of the vehicle.

Abstract: The proposal is for a process for controlling an automatic transmission in which, on the basis of a speed-change demand, an electronic control device determines a mode of changing (F1, F2, F3), compares an existing operation point with a theoretical operation point in which the theoretical operation point depends upon the mode of changing and selects a first or second change range.

Abstract: In a transmission unit (1) for arrangement between a drive motor (47) and a consuming device (48), including a hydrostatic transmission (2), 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.The shift transmission (4) is a synchronous transmission with synchronization devices (7) for the gears (5, 6), includinga 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).

Abstract: There is disclosed an hydrostatic transmission having a control and regulating device for adjusting the driving torque with superimposed output power limit regulation, the transmission comprising a drive unit comprising an hydraulic pump having a variable output, and an hydraulic motor arranged to be operated by the hydraulic pump; a servo-adjusting device arranged to control the output of the hydraulic pump in order to adjust the working pressure in the transmission, said device comprising a servo piston arranged for two-way adjustment of the hydraulic pump in two directions, and a control valve arranged to subject the servo-piston to an adjusting pressure so that the piston can adjust the operation of the hydraulic pump; a servo-valve spool provided in said control valve and arranged, in dependence upon the desired direction of adjustment of the hydraulic pump, to be subjected on the one hand to a control pressure and on the other hand to the working pressure prevailing in the transmission or a regulating p