Motion reliability analysis of crank-slider mechanism with multi-tolerances

An error analysis method with mixed clearance and multi-dimensional tolerances for the offset crank-slider mechanism was proposed in this research. Taking reliability and motion defect-free as performance probability constraints, an optimized design model of mechanism motion accuracy reliability with multi-tolerances was established, which aimed to minimize the maximum failure probability of trajectory point motion accuracy. Taking the rod length and dimensional tolerances into account, the global motion region of the slider in 12 schemes was optimized. Based on the optimization, the optimal design variables such as rod length and tolerances were obtained. The influence of mixed clearances on the reliability of the kinematic accuracy of the mechanism was analyzed quantitatively. The results show that the motion error of the forward interval of the slider is larger than that of the return interval, while the stationarity is lower. while the prismatic clearances increased from 0.01 to 0.02 and 0.03mm, the failure probability increased by 22.87% and 48.27%, respectively. With additional revolute clearances set to 0.0072mm, the corresponding additional increment of failure probability was 5.31% and 5.19%, respectively. Furthermore, enlarging the revolute clearances to 0.0193mm, the failure probability increased by 7.22% and 13.24% additionally. Based on both manufacturing cost and reliability, the design schemes were evaluated comprehensively, and reasonable suggestions for the selection of the optimal design scheme were given.