The Consequences of Spline Friction in Multiple Disk Brake and Clutch Packs

A mathematical analysis is offered showing the various consequences of spline friction in multiple disk systems. Included are equations for the load variation through a multiple disk pack, the effect of interfacial pressure distribution on this load variation, the torque variation through a pack, and the total torque carried by a pack. The relation between friction and velocity is taken into account. The coefficient of friction determined from the data of a multiple disk test apparatus, ignoring spline friction, is shown to be significantly in error and an equation is derived for calculating the true coefficients of friction. Examples of the load variation in a pack are derived and the results plotted.