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Why hydraulics?
4
The clutch is the interface between the engine and
the gearbox. This interface can be disengaged via
a release system connected to the clutch pedal to
enable gear changes. In engaged position, the disc
is squeezed between the two friction surfaces of
the flywheel and the pressure plate of the clutch
cover. To disengage a push or a pull type clutch, it
is necessary to push or to pull the fingers of the
diaphragm. The pressure plate then moves against
the flywheel and releases the friction. The clutch is
then disengaged. This release system can be either
mechanical (by clutch cable) or hydraulic.
The mechanical clutch release system consists of
a release bearing that is operated by a fork. The
fork is attached to a clutch cable operated by the
driver’s foot via the clutch pedal. Cars have become
lighter and more compact. Car manufacturers
demand reduced pedal load linked to comfort
reason. Hydraulic systems become mandatory in
such cases as they also provide benefits compared
to the manual system, increasing efficiency of the
actuation with less space required.
For these reasons, one vehicle out of two is equipped
with a hydraulic system today.