Patent ID: 8788161

Claim:
A method for setting an operating pressure of a transmission, the transmission having at least one of clutches, brakes, actuators, a hydrodynamic clutch, and a hydrodynamic converter, to which a medium conducting the operating pressure can selectively be applied, in order to vary a transmission ratio of at least one of a speed and a torque between a transmission input shaft and a transmission output shaft by opening and closing at least one of the clutches and the brakes, by actuating the actuators, and/or by a hydrodynamic power transmission using at least one of the hydrodynamic clutch and the hydrodynamic converter, wherein the operating pressure being switchable between a constant nominal value and a constant decreased value that is smaller in relation thereto, or the operating pressure being reducible in three or more steps or continuously from a nominal value to a decreased value, the method comprising: detecting a speed difference between the transmission input shaft and the transmission output shaft and/or between an input side and an output side of at least one of the clutches, the brake, the hydrodynamic clutch, and the hydrodynamic converter; comparing the speed difference to a predefined target difference; switching or reducing the operating pressure, the switching or the reducing being performed as a function of the comparing; wherein one or more variables describe a permissibility of the switching or the reducing and include: a torque applied to the transmission input shaft; a torque applied to the transmission output shaft; a power applied to the transmission input shaft; a power applied to the transmission output shaft; a speed of the transmission input shaft and/or the transmission output shaft; a power supplied at a secondary drive of the transmission and/or a torque of a drive machine supplied there; a torque applied to a secondary output of the transmission and/or a power applied there; the method further comprising: detecting an engine drag torque; and specifying a limiting value for the engine drag torque describing the permissibility of the switching or the reducing, wherein the switching or the reducing is only performed upon detection of a variable describing the permissibility of the switching or the reducing below the limiting value, the limiting value being varied as a function of the comparing of the speed difference to the predefined target difference.