Study on the Influence of Structural Parameters on the Performance of an Internal Feedback Hydrostatic Bearing

Hydrostatic spindles are key components in high-precision grinding machines. In this paper, an internal feedback radial–thrust combined hydrostatic bearing is proposed to improve the load-carrying performance of conventional hydrostatic spindles. The throttling structure is integrated into the bearing inner surface, and an internal feedback throttling configuration is developed to enhance pressure regulation and reduce nterference between oil pockets. Based on fluid lubrication theory and the hydraulic resistance network method, a theoretical model of the combined bearing is established, and a systematic parameter design method is developed. The governing equations of flow, pressure, load-carrying capacity, and stiffness are derived for performance prediction and structural design. Furthermore, finite element simulations are conducted to investigate the effects of key parameters. The simulation results show that, at a supply pressure of 4 MPa, the radial stiffness reaches 2559.3 N/μm and the axial stiffness reaches 423.1 N/μm. The simulation results are compared with the theoretical predictions, showing good agreement and providing numerical verification of the proposed theoretical model.