Method for operating a driving device of a working machine

A method for operating a drive device (1) for a working machine (100), wherein the drive device (1) has an engine and a power-split gearbox (3) with a variator (5) for continuously variable adjustment of a transmission ratio of the gearbox and wherein the drive device (1) has a conventional maximum traction force curve (hZ) in which the maximum permissible traction force (Z) of the drive device (1) increases with decreasing output speed of the drive device (1), the method comprising:

• receiving (II) an activation signal for activating a grading operation of the working machine (100), wherein the grading operation has a limited maximum traction force curve (IZ1;
• IZ2;
• IZG) and in which the maximum permissible traction force (Z) of the drive device (1) increases less sharply than in the conventional maximum traction force curve (hZ) as the output speed of the drive device (1) decreases;
• ascertaining (V) a currently maximum permissible traction force (Z) based on the limited maximum traction force curve (IZ1;
• IZ2;
• IZG);
• comparing (VI) a current traction force (Z) with the currently maximum permissible traction force (Z);
• and
• adjusting (VII) the transmission ratio of the gearbox (3) towards a lower output speed of the drive device (1) based on the comparison.