Effect of oil pad offset ratio on the static and dynamic characteristics of a radial hydrostatic rotor–bearing system
Ruirui Li, Kai Zhang, Xiangbo He, Xiaosheng Liang, Dongping Zhan, Yunfeng PengPurpose
This study aims to investigate the effects of oil pad offset, treated as a controllable design parameter, on the static performance and dynamic response of radial hydrostatic rotor–bearing systems under space-constrained conditions.
Design/methodology/approach
A coupled hydrostatic bearing–rotor dynamic model incorporating oil pad offset is established. The transient Reynolds equation and mass flow conservation are solved to evaluate load-carrying capacity and equivalent stiffness. An eight-degree-of-freedom rotor dynamic model based on Timoshenko beam theory is constructed, in which the bearing characteristics are integrated to analyze the nonlinear vibration response. An orthogonal experimental design is further employed to quantify the coupled effects of structural parameters and operating conditions.
Findings
The results demonstrate that oil pad offset significantly influences bearing load capacity, stiffness and rotor vibration behavior. Appropriate combinations of oil pad offset ratio and average oil film thickness can effectively enhance stiffness and improve dynamic stability, whereas excessive offset may deteriorate vibration performance.
Originality/value
By explicitly treating oil pad offset as a designable parameter rather than an unintended asymmetry, this study provides a systematic analysis framework and practical guidance for the optimization of hydrostatic bearings in compact spindle systems.