Control device for continuously variable transmissions

摘要

In the hydraulic control device a pressure-reducing valve (MF) is used to produce the belt-tightening pressure for the two pairs of disks (SSA, SSB) of a cone-pulley transmission, while the function of shifting the transmission ratio is performed by a ratio-shifting valve device (DBV13) that adds pressure fluid to one and simultaneously removes pressure fluid from the other of the pairs of conical disks. The pressure-reducing valve and the ratio-shifting valve device work in a cascade arrangement where the assurance of a sufficient belt-tightening pressure takes precedence over the ratio-shifting function.