Nonlinear dynamic analysis of cutting head-rotor-bearing system of the roadheader

Abstract

In order to study the dynamic characteristics of cutting head and cantilever system, a nonlinear dynamic model with a 13 degrees of freedom (13-DOF) lateral torsional coupled cutting head-rotor-bearing system (CHRBS) is established. The nonlinear coupled factors of spline clearance and bearing contact force are mainly considered, the dynamic analysis of CHRBS under time-varying load is carried out. The results show that there is no positive correlation between the cutting rock thickness and the states of chaotic motion and quasiperiodic motion. The system is in the two states mentioned above when in low speed region. With the increase of rotational speed, the chaotic motion becomes periodic motion. When the hardness of rock is lower, increasing rotational speed can reduce the vibration of the system, and the cutting thickness can be increased to improve the productivity and lump rock rate. As the hardness of rocks increases, the coupled system shows complex dynamic characteristics when the rotational speed changes from low to high, and the vibration increased. When cutting hard rock, the cutting speed should be increased. However, when the speed is too high, the cutting torque of system becomes smaller. In the case of cutting hard rock, reasonable rotational speed should be chosen between improving stability and increasing cutting force. The dynamic analysis results provide strong support for the vibration reduction and dynamic design of roadheader.