FLUID-THERMAL-MECHANICAL COUPLED SOLUTION AND EXPERIMENT ON DEFORMATION OF BEARING FRICTION PAIRS IN HYDROSTATIC BEARING

The deformation of friction pairs has a significant influence on friction performance of hydrostatic bearing, and the non-uniform deformation will result in oil film rupture, dry friction, and even friction failure. The fluid-thermal-mechanical interaction model of oil hydrostatic bearing with annular slit restrictors is established. The deformation of hydrostatic bearing friction pairs has been solved through fluid-thermal-mechanical coupled method based on computational fluid dynamics, elastic theory and finite element method. The relationship among the deformation of hydrostatic thrust bearing and rotational speed and workbench weight is established, and its deformation distribution law is revealed. A test rig is established for testing deformation. The results show that the experimental data are basically identical with the simulation results, and demonstrate the validity of the proposed numerical simulation method. The results prove that the clearance oil film temperature of hydrostatic bearing rise sharply and the thermal deformation is also increasing with the increase of rotational speed. The thermal deformation are homogenized by the elastic deformation caused by the workbench weight, but the squeeze effect will increase the thermal deformation. The deformation of the rotating workbench and the base is like a trumpet. The inner edge is closing and outer edge is opening. By further increasing the rotational speed and load weight, the lubricating oil viscosity declines sharply, the oil film grows thin quickly, the bearing friction pair exhibits uneven deformation, and the local bearing friction pairs sustain boundary lubrication or dry friction which may cause the friction failure.