Experimental research and dynamics analysis of multi-link rigid–flexible coupling mechanism with multiple lubrication clearances

Clearance joint and component flexibility are the key factors affecting the dynamic performance of mechanisms. Lubrication clearance joint can effectively improve dynamic responses and slow down collision and wear of the clearance joint. There are few researches on dynamic of planar complex multi-link mechanism considering the coupling action of clearance, lubrication, and elasticity of member. In this paper, the 2-DOF nine-bar mechanism which can be used as the main transmission mechanism of hybrid-driven multi-link press was taken as the research object. Considering the coupling action of lubrication clearance and element flexibility, a dynamic model of rigid–flexible coupling multi-link mechanism (RFC-MLM) with multiple lubrication clearances was established. Influences of lubrication clearances on dynamic of rigid/rigid–flexible coupling mechanisms were investigated. Effects of dry friction/lubrication clearances on the dynamics of the RFC-MLM were also studied. The influences of dynamic viscosity, clearance value, driving velocity, and cross-sectional dimension on the dynamics of the RFC-MLM were comprehensively analyzed. A 2-DOF nine-bar mechanism test platform containing multiple lubrication clearances was constructed to verify the correctness of theoretical model.