How the clutch works
Cross-sectional view of a single disc dry clutch
| Item | Description |
|---|---|
| A | Clutch disengaged |
| B | Clutch engaged |
| 1 | Flywheel |
| 2 | Clutch disc |
| 3 | Pressure plate |
| 4 | Diaphragm spring |
| 5 | Transmission input shaft |
| 6 | Clutch cover |
| 7 | Crankshaft |
The clutch transmits engine torque from the engine to the transmission. When the clutch pedal is pressed the power from the engine to the transmission is interrupted.
When the clutch pedal is not pressed the clutch is engaged. Pressing the clutch pedal disengages the clutch.
A dry clutch usually only has one clutch disc, the coatings of which are specially designed for dry friction with a higher coefficient of friction. The torque which can be transmitted also depends on the size and number of friction surfaces and the pressing force.
The flywheel and pressure plate are connected to the crankshaft in a rotationally fixed way and transmit the torque via the friction linings of the clutch disc to the input shaft of the transmission. The clutch disc is clamped between the flywheel and the pressure plate. The force from the diaphragm spring provides the necessary contact pressure.
The clutch cover, pressure plate and diaphragm spring are also referred to as the clutch pressure plate.
The wear on the clutch disc is greatest at the pressure point during engagement of the clutch. If the pressure plate is moved away from the flywheel then there is no longer any friction to the clutch disc, and the connection is disengaged.
The most frequent damage observed on the clutch is too low friction (sliding) between the clutch disc and the pressure plate or flywheel. This can be caused by oil leaks, friction lining wear or a weak diaphragm spring.