Dynamic characteristics analysis and experimental verification of multi-link press mechanisms with lubrication clearances under impact load conditions

In the practical application of multi-link mechanism, lubricating oil has been widely used in kinematic pairs to reduce the influence of clearance on the accuracy and stability of the mechanism. However, the operation of the press is still inevitably affected by the impact loads. Impact loads will also reduce dynamic response characteristics of the mechanism and affect its accuracy and reliability. At present, the research on dynamic response characteristics of mechanisms mainly focuses on the effect of lubrication clearances. Theoretical research on dynamic of mechanisms with lubrication clearances under impact loads is rare. Experimental studies involving impact loads are uncommon. Therefore, an effective approach for dynamic characteristics of multi-link mechanism with lubrication clearances under impact loads was proposed, and the dynamic response of multi-link presses with lubrication clearances under impact loads was studied in the article. Taking a seven-link press mechanism as an example, a dynamic equation of the mechanism with lubricating clearance was derived based on the Lagrange multiplier method. The dynamic model of the seven-link press mechanism with lubrication clearance under impact load was developed. Then the effects of lubrication conditions, dynamic viscosity, driving speeds, and impact loads on dynamic characteristics of press mechanisms were analyzed, respectively. Finally, an experimental platform consistent with the theoretical model was built. Through the experimental research and the analysis of experimental results, the rationality of models and the validity of theoretical analysis were verified. The study provides a method for understanding dynamic characteristics of presses during impact loads, and provides an important reference for dynamic optimization design of multi-link press mechanism.