Method of controlling speed changing rate for metal belt type non-stage transmissions

摘要

In a metal belt-type continuously variable transmission, the radius of winding a metal belt around a drive pulley is increased to change the shift ratio i by applying a larger first axial thrust to the drive pulley and a smaller second axial thrust to a driven pulley during upshifting. In a region B where the relationship between a first axial thrust and the gear shifting speed dR/ds defined as a value obtained by differentiating the radius R of winding of the metal belt around the drive pulley by an amount s of tangential movement of the metal belt is maintained substantially linearly, the first axial thrust is subjected to a feedforward control based on a target gear shifting speed dR/ds. In regions A and C where the relationship between the first axial thrust and the gear shifting speed dR/ds is not maintained substantially linearly, the first axial thrust is subjected to a feedback control, so that the gear shifting speed dR/ds is equal to the target gear shifting speed dR/ds.