Dynamic responses of gear-linkage mechanism considering mixed clearances: Simulation and experiment

Clearances, resulting from assemblage, manufacturing errors and wear, always lead to undesirable vibrations due to impact forces in clearance joints. Usually, there are inevitably clearances between bearing and shaft in revolute joints as well as tooth backlash in gear pairs of gear-linkage mechanism system, which is widely used in mechanical engineering. However, in dynamics analysis of gear-linkage mechanism, it is usually assumed that the coupling relationship between the revolute clearance joint and backlash of gear pair is ignored. In this work, the effects of multiply clearances on the dynamic responses of planar gear-linkage mechanism system are investigated using computational and experimental methodology. Firstly, the mathematic models of the radial clearance in revolute joint and tooth backlash in gear pair are established considering the coupling relationship between radial clearance and tooth backlash. Then, the normal contact force model in radial clearance joint is established using nonlinear contact force model. The gear meshing force model is established using dynamic meshing force model considering time-varying meshing stiffness and nonlinear damping coefficient. Finally, a gear-linkage mechanism with multiply clearances is used as application example to implement the investigation. The dynamic responses obtained with numerical simulation are compared with that of experimental gear-linkage mechanism setup. Dynamic tests with different clearance sizes and driving speeds are performed respectively. The comparison between simulation and experimental results shows that the simulation results agree quite well with experimental results, which proves the accuracy and efficiency of the proposed method for dynamic analysis of gear-linkage mechanism system with multiply clearances. The investigation indicates that the radial clearances in revolute joints and tooth backlash in gear pair are interaction with each other, and the existence of clearances plays an obvious effect on the dynamic characteristics of gear-linkage mechanism, which significantly reduce the performance of the gear-linkage mechanism, especially the backlash of the gear pair.