Clutch: Description and Operation

Self-Adjusting Clutch (SAC)
Function
On ordinary clutches, the clutch pedal load increases as the clutch disc wears. The self-adjusting clutch is designed so that the clutch pedal load will not increase even when the clutch disc wears. This is done by automatically adjusting the fulcrum of the diaphragm spring in accordance with the wear of the clutch disc. The clutch pedal load stays consistent even when the clutch disc is worn.

Construction





The self-adjusting clutch consists of a pressure plate, a sensor spring, a diaphragm spring, an adjusting ring, three coil springs, a pressure plate cover, and a compensation spring. They are riveted together anti must not be disassembled.
If there is problem with any part of the pressure plate or clutch disc, they must be replaced as a set.

Operation





1. When the clutch disc wears slightly.
As the clutch begins to wear, the release load increases slightly. However, this does not affect the operation of the clutch because the release load does not exceed that of the sensor.





2. When the clutch disc wears considerably.





The sensor spring starts to deflect as the clutch disc is worn further and the release load exceeds that of the sensor.
The fulcrum then moves following the amount of sensor spring deflection. As this takes place, the fulcrum of diaphragm spring is adjusted, keeping the release load consistent.