The principle of operation of the clutch (Audi 100 C4)

The transmission of torque from the engine to the transmission is accomplished by means of a clutch. It works solely by friction, and can be visualized as follows: two contact surfaces are pressed tightly against a third and hold it so tightly that it is forced to rotate together with the two. The idea behind the design is that this connection can be disconnected at any time, otherwise both of these parts could just as well be screwed together. Let's call them by their names: the flywheel and the pressure plate, loaded by the force of the spring, are rigidly connected to the engine. Between them is a driven disk, rigidly engaged with the gearbox shaft by its teeth.

The next important function is performed by the release bearing: when the clutch pedal is pressed, it is pressed by the clutch control drive (see next section) to the pressure plate and overcomes the force of the pressure plate spring. The driven disk is thus released from its "clamped" position and can rotate freely between the pressure plate and the flywheel. The transmission of torque between the engine and gearbox is stopped. If the clutch pedal is released again, the disc spring of the pressure plate again presses the driven disk against the flywheel, stopping its free rotation in one fell swoop. All three elements again form a rigidly connected connection. The engine torque can be transmitted to the drive.