Dynamic Analysis And Reliability Study Of Shearer Walking Gear Considering Wear

The walking gear is the key component of the shearer's walking mechanism and bears the important task of driving the shearer.Once the fault occurs,the entire shearer will stop working.Because the walking gear and the pin row are open-type transmissions,the working conditions are relatively harsh and the load is large,and the tooth surface wear is prone to occur,which causes the vibration and impact during the running process to become more and more serious,and also induces the broken teeth of the walking gear.Therefore,it is necessary to analyze the tooth surface wear and dynamic characteristics of the walking gear,so as to provide a theoretical basis for slowing the wear and improving the reliability of the walking gear.In this paper,the MG300/700-WD shearer walking gear is taken as the research object,and the wear surface and nonlinear dynamic of the walking gear are analyzed.Based on this,considering the influence of wear and fatigue,the gradual reliability of tooth surface contact strength and the reliability analysis of tooth root bending strength are analyzed.The main research contents are as follows:(1)Using the AN SYS software,the quasi-static finite element simulation model of the walking gear and pin row meshing transmission is established.The time-varying meshing stiffness of the walking gear is solved by the finite element method and compared with the theoretical analytical method.Then the effects of walking gear parameters on the time-varying mesh stiffness are studied.(2)Considering the wear degradation of the walking gear,the numerical calculation model of surface wear of the walking gear is established.Based on this,the backlash model of walking gear is established.The influence of walking gear parameters on wear degradation process is further studied.(3)A single-degree-of-freedom dynamic model of the walking gear and pin row meshing pair with nonlinear factors such as time-varying stiffness and time-varying backlash is established.The dynamic response of the walking gear and the dynamic meshing force and dynamic stress of the structure in different wear cycles under smooth conditions are obtained,and the influence of walking gear parameters on dynamic response characteristics during wear degradation is further analyzed;(4)Considering the influence of wear and fatigue,the gradual reliability model of the tooth surface contact strength and the gradual reliability model of the root bending strength are established respectively.Then the gradual reliability and reliability sensitivity of the walking gear are analyzed based on the improved first-order second moment method.The research results show that the dynamic response of the walking gear in the process of wear degradation have an impact,and it increases with the wear cycle,which has a great impact on the gradual reliability of the walking gear.Therefore,when analyzing the gradual reliability of the walking gear,it is necessary to consider the effects of wear and fatigue at the same time.