Hydrodynamic and hydrostatic modelling of hydraulic journal bearings considering small displacement condition

13th International Conference on Motion and Vibration Control; 12th International Conference on Recent Advances in Structural Dynamics

Chen, Chi-Yin^1 ; Chuang, Jen-Chen^1 ; Tu, Jia-Ying^1

Advanced Control and Dynamic Test Laboratory (ACDTLab), Department of Power Mechanical Engineering, National Tsing Hua University, Hsinchu

300, Taiwan^1

关键词: Active control systems;    Hydrostatic stiffness;    Journal bearing systems;    Modified coefficient;    Online prediction;    Pressure variations;    Small displacement;    Theoretical derivations;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/744/1/012099/pdf
DOI  :  10.1088/1742-6596/744/1/012099

来源: IOP

【 摘 要 】

This paper proposes modified coefficients for the dynamic model of hydraulic journal bearing system that integrates the hydrodynamic and hydrostatic properties. In recent years, design of hydraulic bearing for machine tool attracts worldwide attention, because hydraulic bearings are able to provide higher capacity and accuracy with lower friction, compared to conventional bearing systems. In order to achieve active control of the flow pressure and enhance the operation accuracy, the dynamic model of hydraulic bearings need to be developed. Modified coefficients of hydrostatic stiffness, hydrodynamic stiffness, and squeeze damping of the dynamic model are presented in this work, which are derived referring to small displacement analysis from literature. The proposed modified coefficients and model, which consider the pressure variations, relevant geometry size, and fluid properties of the journal bearings, are able to characterise the hydrodynamic and hydrostatic properties with better precision, thus offering the following pragmatic contribution: (1) on-line prediction of the eccentricity and the position of the shaft in the face of external force that results in vibration; (2) development of active control system to regulate the supply flow pressure and to minimize the eccentricity of the shaft. Theoretical derivation and simulation results with different vibration cases are discussed to verify the proposed techniques.