DEVICE FOR INCREASING THE FUNCTIONAL RELIABILITY OF A HYDRAULIC CIRCUIT OF A HYDRAULICALLY OPERABLE CLUTCH

摘要

A known device for increasing the functional reliability for a hydraulic circuit of a hydraulic clutch having a pressure reservoir ( 25 ) and a release cylinder ( 5 ) which comprises a primary piston ( 14 ) and a secondary piston ( 16 ). A compensation volume is developed in the sense that when the vehicle is at a standstill and the parking brake released, an unintentional release of the clutch is prevented. A pressure-monitoring/pressure-supply device ( 28 ) is used for determining a reference operating pressure and establishes a static pressure which, in case of any system error, only allows displacement of the secondary piston ( 16 ) such that the contact pressure of the clutch discs, against one another, is still sufficient to maintain the vehicle at a standstill.