Friction clutches - the most commonly used.
In cars, friction clutches are most often used. The principle of operation of the clutch is as follows: A flywheel is permanently bolted to the rotating crankshaft of the engine, which is also the metal plate of the clutch. A clutch disc lined with a friction material with a high coefficient of friction is pressed against the flywheel. Because when the clutch disc is away from the flywheel, the friction between the discs is absent and the input shaft does not rotate. If, on the other hand, the clutch plate is moved along the clutch shaft and pressed against the flywheel, this will rotate with the crankshaft. If the clutch friction plate has some slip with respect to the flywheel, the speed of the clutch shaft will be less than the speed of the engine. A very strong spring prevents the clutch disc from slipping, which constantly presses the clutch plate against the flywheel. Thus, the clutch is engaged.
The clutch pedal is used to disengage the clutch. In fact, the car friction clutch is more complex. Clutch friction plate, to which special friction linings are attached on both sides, it is pressed on both sides to use a larger friction surface. A bowl-shaped clutch cover is bolted to the flywheel, which houses several coil springs. These springs press the clutch disc against the flywheel by means of a special pressure ring.