METHOD FOR CONTROLLING A NORMAL FORCE IN A FRICTIONAL CONTACT OF A CONTINUOUSLY VARIABLE TRANSMISSION

摘要

A method is provided for controlling a normal force in a frictional contact of a continuously variable transmission comprising an input pulley and an output pulley where between an endless transmission means is arranged that is held between and in frictional contact with two pulley discs of each respective pulley under the influence of a respective normal force, wherein, as part the control method, the normal force at one pulley is actively oscillated, wherein a resulting oscillation of one of, or a ratio or difference between both of, a rotational speed of the input pulley and a rotational speed of the output pulley is determined and wherein at least one normal force is controlled in dependency on a correlation between the said active oscillation and the said resulting oscillation. The method comprises a calibration step wherein a phase difference between the said active oscillation and the said resulting oscillation is determined.