Adding plates to a clutch unit to form a multi-plate clutch will increase its torque capacity, without increasing spring strength or clutch diameter.
This clutch assembly has two friction discs, with friction material riveted to both sides of each.
An internally-splined hub on each disc mates with the splines on the transmission input shaft.
A cast-iron separator plate fits between each disc. The separator plate locates on driving pins on the flywheel.
This friction unit is between the flywheel and the pressure plate when the pressure plate assembly is bolted to the flywheel. The pressure plate spring then provides a frictional clamping force on each mating surface.
Torque is transmitted from the flywheel through the friction facings to the transmission input shaft.
When the clutch pedal is depressed the release bearing acts on the pressure plate diaphragm and moves the pressure plate away from the flywheel.
This releases the clamping force on the facings and separator plate and allows each clutch driving member to rotate freely without turning the transmission input shaft.
When the pedal is released, the spring tension forces the pressure plate, discs and separator against the flywheel, clamping all components together.