Gangwechsel-Steuervorrichtung und Verfahren für ein stufenloses Getriebe

摘要

A speed ratio of a continuously variable transmission is varied according to an oil pressure which is adjusted by a valve (4) driven by a step motor. The step motor is feedback controlled so that a real speed ratio coincides with a target speed ratio determined according to the running conditions of a vehicle. By determining a feedback gain based on the oil pressure (66), oil temperature (65), real speed ratio and output shaft rotation speed (63,64) of the transmission, precise control of the speed ratio according to the running state is realized.