A Theory of Contact Loss at Resolute Joints with Clearance

Equations are derived that describe the conditions at a general idealized revolute joint, with clearance but with no hydrodynamic lubrication present. The equations are governed by three dimensionless parameters that depend on the nominal motion, mass distribution and influence coefficients of the linkage in which the joint appears, as well as the clearance magnitude. A series of numerical solutions of the equations is used to predict the conditions under which contact is lost, leading to impacts. The results are presented in the form of a design chart and the implications are discussed.