1, to ensure the smooth start of the car

This is the primary function of the clutch. Before the car starts, it's natural to start the engine. When the car starts, the car accelerates from a completely stationary state. If the transmission system (which links the entire car engine) with rigid links, the transmission of a hanging file, the car will suddenly look ahead, but it does not start. This is because the car from the static to the front of the thrust, resulting in great inertia force, causing great resistance to the engine torque. Under the influence of this inertia resistance, the engine rapidly drops to the minimum steady speed (300-500RPM) in the instantaneous speed, and the engine will stall and not work, of course, the car can not start.

So we need the help of the clutch. After the start of the engine, the car started before the driver to the clutch pedal, the clutch, the engine and transmission system is disengaged, then the transmission gear, and then gradually release the clutch pedal, the clutch engagement gradually. In the bonding process, the engine torque increases gradually, it should also speed up the pedal down gradually, gradually increase the amount of fuel supplied to the engine, the engine speed is always maintained at the minimum stable speed, but will not die. At the same time, because of the close degree of clutch engagement increases, the torque of the engine by the transmission system to the drive wheel will be gradually increased, the traction force to overcome the initial resistance, the car starts from rest and gradually accelerate the movement of 2, ensure that the transmission system Pingshun work shift

2: achieve smooth shift

In order to adapt to the changing driving conditions, the transmission system often needs to change gears in the process of moving. To realize the gear shift of a gear type transmission, it is usually to toggle gears or other gear shifting mechanisms so that a gear pair of the original gear is used to transmit the gear, and then another gear pair of the gear box is put into operation. Shift before the clutch pedal, interruption of power transmission, so that the original gear pair meshing the meshing parts off, the new gear meshing speed gradually into synchronization, when meshing impact can be greatly reduced, to achieve smooth shifting.

3, to prevent transmission overload

When the car brakes, if there is no clutch, engine and transmission system will sharply reduce the rigid connection speed, so all the moving parts of which will have a great moment of inertia (its value may be much higher than the normal maximum torque generated when the engine is working), caused by the load exceeds the carrying capacity of the transmission line. Due to mechanical damage. With the clutch, you can rely on the clutch and the active part of the relative motion between the driven parts to eliminate this danger. Therefore, we need to limit the maximum torque of the clutch transmission system can ensure the safety.

Clutch can be divided into: friction clutch, or the use of fluid as the transmission medium (ie fluid force coupling), or the use of magnetic drive (ie electromagnetic clutch)