CVT contact-pressing device with electronic control, in particular for highly dynamic operating conditions

摘要

Contact-pressing device for CVT (continuously variable transmission), comprising both pressure medium supply devices and open-loop and closed-loop control devices for the contact pressure, for operating conditions having spontaneous torque loading peaks. Ensuring and building up sufficient contact pressure force in the case of highly dynamic operation require relatively large pressure medium supply devices, because of the elasticities necessarily present in the hydraulic and mechanical systems and components of the CVT (inertias). Obvious, correspondingly largely dimensioned contact pressure and adjusting pressure medium supply devices on the CVT, which could undertake this task concomitantly but would have to operate continuously under the highest disk set pressure, are not acceptable on economic grounds. Solutions according to the invention of low-loss, highly dynamic pressure medium supply, open-loop and closed-loop control systems exist in the following embodiment versions as a result of the arrangement of: - a pressure store and a rapidly switching digital-process computer-controlled servo valve which modulates contact pressure peaks to the basic contact pressure set for static operating conditions; - a modification having a differential piston which increases the contact pressure with respect to the store pressure level; - an additional or separate, largely dimensioned hydraulic pump which, in normal operation, delivers in a low-pressure and low-loss manner in a circuit and is only activated as required for the spontaneous increase of contact pressure force. A further useful effect consists... Original abstract incomplete. IMAGE