Abstract: In order to reveal the influence of the bearing clearance and flexibility on the dynamic errors of mechanisms accurately and efficiently, a methodology for dynamic modeling of multibody systems with bearing clearance and flexibility is presented based on the theories of multibody dynamics and Hertz contact. The detailed bearing joint in the multibody system is modeled by introducing a constraint force system instead of the kinematic constraints. The presented methodology provides a foundation for in-depth revealing the relationships between the bearing micro dynamic characteristics and the multibody system macro dynamic performance and kinematic accuracy. A crank slider mechanism including a deep groove ball bearing is used as a numerical example application to analyze the effects of the bearing clearance and flexibility on the position and velocity errors of the mechanism. The results indicate that the variation of the eccentric trajectory of the bearing inner race center with respect to the outer race center is determined by the loading characteristic of the bearing joint in the context of dynamic analysis of multibody system. Under the influence of the bearing eccentricity, the position and velocity errors of the mechanism are usually different with the variation of crank angle position.

Key words: Bearing, Clearance, Dynamic errors, Hertz contact, Multibody dynamics