Transient Hydrodynamic Analysis of Ball Mill Multi-Pocket Pivoted Pad Hydro-static Bearing

Abstract

Abstract Huge ball mill bearings experience a transient period when they are fed with raw material or their basis is impacted. The behavior of such bearings during the transient period is significant to the safety of the machine. In the present paper, the step load is used to simulate this process. Transient hydrodynamic lubricating models of a multi-pocket pivoted pad hydro-static bearing used in ball mill are established. The hydrodynamic and squeeze effects are take into account, and the models are solved using nonlinear numerical methods. The journal center trajectory, time response of the pad tilting, oil pressure in the pockets, and minimum pad film thickness during the transient period are presented. The oil flow rate evolutions out of the main pockets in all pads are exhibited. The effects of step load on bearing performance are discussed. It was found that the decrease in minimum film thickness can be quite large under the step load impact, which may lead to the damage of the bearing.