Research On Dynamic Characteristics Of Drum Shearer Cutting Unit

Drum shearer is the core equipment of underground fully mechanized coal miningand the cutting unit is the main working part of drum shearer. Vibration and shock onthe shearer in the cutting process is mainly transferred through the cutting unit. It issignificance to study the dynamic characteristics of shearer cutting unit for improvingthe reliability, service life, high yield and efficiency of coal mining. In this thesis, thedynamic characteristics of shearer cutting unit have been studied based on vibrationtheory, nonlinear finite element analysis, virtual prototype technology and multibodydynamics.A single freedom degree vibration model of the drum shearer cutting unit heightadjusting has been established based on hypothesis and simplification. Random load onspiral drum is simplified into alternating load in three directions. The cutting unit heightadjusting under different conditions has been modeled and simulated by using softwareMatlab/Simulink, and dynamic responses of the cutting unit ranging arm housing swingunder sinusoidal excitation have been obtained. The results indicate that the systemvibration can be reduced by increasing damping and stiffness of hydraulic adjustingcylinder appropriately, achieving smoothly operation of the system.The dynamics model of cutting system under the interaction of coal seam and drumhas been established by LS-DYNA. Shearer cutting unit coal cutting has been simulatedand dynamic responses of the cutting system have been obtained. The influence laws ofdifferent drum rotation speeds, traction speeds and hydraulic stiffnesses of heightadjusting cylinder on dynamic characteristics on the cutting system are analyzed. Theresults indicate that under the premise of satisfying the cutting efficiency, the vibrationof cutting system can be reduced by selecting a smaller traction speed or larger drumrotation speed.Virtual assembly of the transmission system has been established by Pro/E. Basedon virtual prototype technology and multibody dynamics theory, the multibodydynamics model of transmission system has been established by ADAMS. The dynamicsimulations and vibration detections under different conditions are carried out.Vibrations of the shearer cutting unit ranging arm are obtained under unloaded, constanttorque load and variable loaded conditions. The influence from gear transmissionsystem on the vibration of cutting unit under different loads and the relations amonglongitudinal vibration, lateral vibration and torsional vibration are analyzed, which provides a reference for vibration monitoring, analysis and fault diagnosis of the shearcutting unit.Vibration measurements of shear cutting unit are carried out by using vibration testsystem. The vibration signals of different points under unloaded and loaded conditionsare obtained. The test results are compared with the simulation results to verify thecorrectness of the multibody dynamics analysis method and provide a reference forfuture research about shearer cutting unit.