Investigate the effect of alternative dry frictional clutch disc material on the transient thermal performance of sliding system experimentally under different boundary conditions

Abstract

The thermal characteristics of different types of friction materials are investigated experimentally using new friction clutch material in the present work under different working conditions; such as rotational speed, torque, and sliding time. The magnitude and distributions of the temperature over a cross section of friction clutch element (pressure plate and flywheel) are investigated and compared. The effect of alternative materials for friction lining of clutch disc on the thermal behavior of sliding system with different operating conditions (different rotational speeds, torques and sliding periods) is investigated experimentally. Four friction materials were used (G95, LUk, HCC and Tiger) in order to study the temperature distribution over a cross section of friction clutch element during the sliding period (heating phase), and during the full engagement period (cooling phase), each one of which had different thermal and mechanical properties. The temperature was measured and compared at various points in r-direction and θ –direction at the interface of the contact surfaces between pressure plate and clutch disc and between flywheel and clutch disc It can be observed from the obtained results that the maximum effect on the temperature values occurs when applying maximum torque (4.5 kg.m), maximum initial rotational speed (1200 rpm), and slipping period (30 s) and the temperature values at interface contact decreases when decreasing all the above input conditions values to (2.5 kg.m, 690 rpm and slipping period to 8 s). The results showed that the temperature reduced from (180.4 ℃) for applied torque 4.5 kg.m, initial rotational speed (1200 rpm) and slip period (30 s) to (83.3 ℃) for applied torque 2.5 kg.m, initial rotational speed (680 rpm) and slip period (8 s) for clutch disc (LUK), the difference between them is (53%). It can be observed the same behavior for other three discs (G95, HCC and Tiger) but with different values of temperature. The results show that the temperature is proportional to thickness, and that the temperatures of pressure plate interface are higher than those at flywheel interface; these results are obtained because of the low thermal capacity of the pressure plate compared to the flywheel under the same boundary conditions. The results showed that the maximum value of temperature at outer disc radius from flywheel interface is equal to (Tmax=152.7 ℃) and at pressure plate interface the maximum temperature is equal to (Tmax=159.1 ℃) for the same operating condition using frictional clutch disc G95. .The experimental optimization results showed that the highest temperatures value are obtained when using friction clutch disc (LUk), and minimum temperature is obtained when using (HCC) disc, it was obtained the highest reduction in temperature which were (20 %) compared to (LUK) for the same input condition when used applied torque (4.5 kg.m) initial rotation speed (1200 rpm) and slip period (30 s).