Dynamic Characteristics Analysis And Optimization Design Of Rocker Arm Of Thin Coal Seam Shearer

Rocker arm is an important component of coal shearer in thin coal seam.It will produce strong vibration under the impact of the cutting force of roller,which will lead to wear or fracture of components,and the load of drum fluctuates randomly in the process of cutting coal.The influence on the rocker arm is also random.At present,the research of rocker arm is mostly static analysis or dynamic analysis static optimization.Many assumptions and simplification are implied,which makes the dynamic reliability of the optimized model deviate from the practical application.Therefore,it has important theoretical significance and practical application value to the dynamic characteristic analysis and dynamic optimization design of thin coal seam shearer.Taking the rocker arm of MG80/120-BWD thin coal seam shearer as an object,the dynamic characteristics of its running process are studied in this paper.On the basis of the optimization,the reliability of the optimized rocker arm is verified by simulation and experiment,and the main results are obtained as follows:(1)By using the mathematical algorithm,the real load attribute of cutting coal and rock is obtained,and the random load under actual working condition is obtained by simulating the force condition of the roller,which provides the data support for the analysis of dynamic characteristics of rocker arm.(2)The rigid-flexible coupling model of the cutting part is established and the dynamic analysis of the rocker arm is carried out.The maximum stress position of the rocker arm shell and the time-history curve of the output stress are found.According to the fluctuation of the curve,the variation rule of the rocker arm stress is analyzed.(3)Aiming at the improvement of simulation efficiency of finite element model for dynamic analysis of rocker arm shell,the hexahedral mesh of rocker arm shell is established.The solid element is used in the main part of rocker arm,and the equivalent mass point is used to replace the various transmission systems.The rest of the support is replaced by stiffness spring,and the simulation efficiency is improved.(4)The topology of the rocker shell is optimized by ANSYS software,and the quality of the rocker shell is reduced.The strength of the shaker shell is guaranteed by adding a stiffened plate at the bottom of the output,so as to improve the second modal frequency and improve the stiffness of the rocker shell.The harmonic response analysis of the optimized rocker arm shows that the peakvalue of dynamic stress is obviously reduced and the first order natural frequency of the rocker arm shell is also increased.(5)The vibration experiment of the optimized rocker-arm shell is carried out,and the displacement response of the rocker-arm shell under operating mode and no-load state is extracted.The error difference between the simulation modal frequency and the displacement response of the optimized model is very small by comparing with the simulation modal frequency and displacement response of the optimized model.The reliability of the optimization model is verified.There are 86 graphs,11 tables and 62 references in this paper.