Friction clutch is the most widely used is the longest class of a clutch, it is basically by the active part, driven part, compression mechanism and control mechanism of four parts. The main and driven parts and the pressing mechanism are the basic structures which ensure that the clutch is engaged and capable of transmitting power, and the clutch operating mechanism is mainly a means for separating the clutch. During the separation process, the clutch pedal is depressed and the free clearance of the clutch is first removed during the free travel, and then the separation gap is generated during the working stroke and the clutch is separated. During the joining process, the clutch pedal is gradually released and the platen is moved forward by the action of the compression spring. First, the separation gap is eliminated and a sufficient pressing force is applied to the platen, the driven plate and the flywheel working surface. Separate bearings in the role of the return spring to move back, resulting in free clearance, clutch engagement.