On the Effect of Bearing Clearances in the Dynamic Analysis of Planar Mechanisms

Abstract

A systematic procedure for the dynamic analysis of planar mechanisms with multiple clearances is presented. Each link of the mechanism is considered as a rigid member, and contact modes are detected by iteration according to the inequalities of input torque and pin forces. The method is useful for predicting the number and frequency of contacts and separations occurring in the mechanism-joints for one complete cycle of the input crank. A four-bar mechanism is used to illustrate the procedure. Results show that there are significant changes in accelerations, torque and pin forces as compared with the case without clearances. Minimal changes have been detected in displacement and velocity relationships. The model presented in the paper provides a design method for investigating torque requirements, pin forces and separation occurrences in high-speed machines with clearance.