Research On Comprehensive Lubrication Performance Of Static And Dynamic Pressure Hybrid Static Pressure Bearing

Due to its many advantages,hydrostatic thrust bearings have become the core components of large-scale CNC equipment in major national industries such as large machinery,aerospace,marine and defense military.With the development of science and technology,the requirements for its carrying capacity and accuracy are getting higher and higher in the manufacturing process.When the hydrostatic thrust bearing is operated under the conditions of high speed and heavy load,the lubricating oil film will be strongly squeezed and strongly sheared.The temperature value and the pressure value of lubricating oil film increases.The oil film becomes thin.The boundary lubrication or dry friction is locally formed.Tribological failure phenomenon often occurs.When the higher the rotation speed,The probability of tribological failure will be higher.A new type of static and dynamic pressure hybrid hydrostatic support structure is proposed in order to solve the above problems,and realizes dynamic and static pressure mixing lubrication and prevents tribological failure,and ensures high precision and stable operation of high-speed and heavy-load hydrostatic support.A new static and dynamic pressure hybrid static pressure support structure is designed.The oil pad and the base are connected by the clearance fit between the pin and the pin hole.During the running of the workbench,the oil pad will be automatically tilted to form a dynamic pressure effect to compensate for static pressure loss.The bearing capacity equation,oil film thickness equation,oil film stiffness equation and temperature rise equation of static and dynamic pressure hybrid hydrostatic bearing double rectangular oil cavity are deduced in detail,which providea concrete calculation process and theoretical basis for analyzing the comprehensive lubrication performance of static and dynamic pressure hybrid hydrostatic bearing.The three-dimensional geometric model of the oil film of the new type static and dynamic pressure structure is established by UG software.The meshing of the model is carried out in ICEM CFD.Finally,the boundary conditions are set and post-processed to obtain the pressure field,temperature field and flow field of the oil film in ANSYS CFX.Considering the pressure field,temperature field and flow field,the optimal oil pad inclination angle is obtained when the comprehensive lubrication performance is the best.At the same time,the influence of load and speed on the lubrication performance of the bearing under normal working conditions is analyzed.In order to verify the correctness of the theoretical derivation and simulation results,the experiment will be carried out on the static and dynamic pressure hybrid static pressure support test bench.The thickness of the oil film will be measured.The tilt angle of the oil pad will be calculated by the data,which was based on the simulation results.Above,the oil film pressure and temperature will be measured under the optimum lubrication performance.After verification,the experimental data and simulation results are consistent within the error range,which proves the accuracy and correctness of the conclusions obtained.