Motor vehicle with alternatively selectable all-wheel drive

摘要

The motor vehicle (10) has a rear axle (22) mechanically driven in conventional manner by the drive motor (14) via a gearbox (16) and a universal shaft (24; 26). An oil-hydraulic pump is so arranged in the transmission train between the gearbox (16) postconnected to the drive motor (14) and the mechanically driven rear axle (22) that it is driven at a speed proportional to the universal shaft (24; 26). The pump is connected via pressure lines (32; 34) to oil-hydraulic motors (36; 38), each of which drives one wheel of a further axle which is not mechanically driven, that is the pump and the oil-hydraulic motors form a hydrostatic transmission which drives the wheels of the axle (18; 20) to be additionally driven at a speed corresponding to the speed of the wheels of the mechanically driven axle (22). By means of a directional control valve the pressure lines (32; 34) can be alternatively short-circuited, as a result of which the power train via the hydrostatic transmission is interrupted. <IMAGE>