Zf Friedrichshafen Ag

Karl K&uuml;hner

Andreas Schwarz

Manfred Sieger

J&ouml;rg Geis

The invention is based on a process for determination of a coefficient of friction (&mgr;) of a hydraulically activated coupling ( ) or brake ( ) in a load-shifting transmission ( ). It is proposed that a drive shaft ( ) of the transmission ( ) be driven with a specified torque (T), that an output shaft ( ) of the transmission ( ) is blocked with a closed coupling ( ) or brake ( ) during a calibration run, the activation pressure (p) of coupling ( ) or brake ( ) is reduced in accordance with a specified course over time, the differential rotational speed (&Dgr;n) between the input ( ) and the output ( ) of the coupling ( ) or brake ( ) is recorded, the activation pressure (p) is ascertained in which the differential rotation speed (&Dgr;n) is greater than zero and a separation coefficient of friction (&mgr; ) is computed on the basis of torque (T), activation pressure (p) and a construction-conditioned coupling constant. By ascertaining the coefficient of friction &mgr;, the shifting can be conducted over the lifetime of the transmission ( ) with a constant shift quality.

Growing community of inventors

Friedrichshafen, Germany

Karl Kühner

Growing community of inventors

Friedrichshafen, Germany

Karl K&uuml;hner

Karl Kühner