The working principle of automobile clutch is that the torque sent by the engine is transmitted to the driven plate through the friction between the flywheel and the contact surface between the pressure plate and the driven plate. When the driver depresses the clutch pedal, the large end of the diaphragm spring drives the pressure plate to move backward through the transmission of the parts. At this time, the driven part is separated from the driving part.
The automobile clutch is located in the flywheel housing between the engine and the gearbox. The clutch assembly is fixed on the rear plane of the flywheel with screws. The output shaft of the clutch is the input shaft of the gearbox. In the process of driving, the driver can press or release the clutch pedal as needed to temporarily separate and gradually engage the engine and gearbox, so as to cut off or transmit the power input from the engine to the transmission.
When the foot leaves the pedal, the spring pushes the pressure plate in the direction of the clutch plate, squeezing the flywheel. This locks the engine to the transmission input shaft so that they rotate at the same speed. The clutch force depends on the friction between the clutch plate and the flywheel and the pressure of the spring on the pressure plate.
When the clutch pedal is depressed, the cable or hydraulic piston will push the release fork and press the release bearing towards the middle of the diaphragm spring. As the middle part of the diaphragm spring is pushed in, a set of pins near the outside of the spring will cause the spring to pull the pressure plate away from the clutch plate, which can separate the clutch from the rotating engine.