Analysis and Verification on Friction Discs Buckling in Multi-disc Clutch

This paper aims to study the bucking process of splines in the outer edge of clutch friction disks under the action of circumferential torque. Specifically a calculation model is set up for each order of critical bucking moment when friction disks buckle, the effects of structural parameters like thickness on each order of critical buckling moment are quantitatively analyzed, and the calculation results of friction disks buckling model are verified by the friction and wear tests of clutch under low speed low load conditions. The results show that before the thermal warping of friction disks caused by large temperature gradient occurs, the action of torque make splines buckle, leading to significant rise in local contact pressure between friction disks and resulting in circumferential pressure fluctuation and thermo-elastic instability. For commonly used friction disks in engineering, a ratio of thickness over pitch circle radius larger than 0.0155 can significantly enhance the twist deformation resistance of friction disks, and hence increase the contact area of friction interface, lower its specific pressure and improve friction condition.