Study on wear characteristics of boom front fork pin hole in the small excavator

Wear in boom front fork pin holes critically affects excavator performance, with small agricultural excavators under complex loading conditions prone to abnormal wear. Considering the actual working conditions of small agricultural excavators and the assembly characteristics of their boom front fork, this study proposed a hypothesis of rotation-swing compound motion of the pin within the pin hole and established a acorresponding finite element analysis model. The model's validity was verified by comparing compound motion simulations with actual wear morphologies, showing high consistency in key wear characteristics. Integrating dynamic analysis, material friction experiments, and Archard wear theory, the model simulated pin hole wear characteristics under non-limit eccentric loading. The effects of assembly clearance, friction coefficients, and compound rotation angle on the pin-pin hole contact and wear were separately analyzed. Additionally, a “Partitioned Wear Volume Analysis” method was developed for wear visualization. The findings reveal that: Increased assembly clearance significantly reduces effective contact area while elevating localized contact pressure, substantially accelerating wear progression; Higher friction coefficients induce more irregular stress distributions and elevated compound contact stresses, thereby intensifying wear severity; While the total wear area remains relatively stable, larger compound rotation angles produce more spatially dispersed wear patterns, expanding the overall wear-affected region. The findings reveal the actual wear behavior of the boom front fork pin hole, providing new insights for the prediction of wear in complex friction pairs, and offering a theoretical foundation for the design and maintenance strategies of joint structures in small-scale construction machinery.