In general, a clutch characteristically requires response characteristics, such as soft gearshift and fast and high transmission power, as a mechanical element for transmitting power wherein a driving shaft and a driven shaft are connected to each other in mechanical devices. This clutch can be used for various industrial areas such as automobiles, motorcycles, industrial machines, presses, ships, etc.
In particular, the clutch used for automobile is designed to allow slippage movement by half clutch operation to attain soft start for vehicles. Accordingly, high-temperature frictional heat can be created within the range of 200° C.˜600° C. with this half clutch operation.
As a result, the clutch undergoes phenomena such as thermal load and fatigue, dynamic load by intermittent contact torque of the clutch caused by friction, and deterioration of clutch cover and disk at high temperature due to friction over the areas such as flywheel, clutch disk, press plate, etc. since high torque power is transmitted by friction.
Caused by this phenomena, fatigue, crack or the like are created by thermal load and dynamic load, and also fading is created due to the reduced friction coefficient at high temperature as well as at high RPM (revolutions per minute). This is the main cause for reducing the life of a clutch.
Various studies for solving the above-mentioned problem have been progressed until now. As for known solutions for these problems, there are a clutch cushion plate, a rubber damper, wave spring, etc. which are used for the shock absorption structure, and also a method of providing ventilation grooves at clutch disk or providing holes at flywheel or press plate was developed as cooling system.