Research On Static And Dynamic Characteristics Of Oil Pad Tiltable Hydrostatic Thrust Bearing Under Offset Load

Modern industry has increasingly strict requirements on the machining accuracy and stability of heavy-duty CNC machining lathes.As the core component,hydrostatic thrust bearings have a direct impact on the performance of heavy-duty CNC machining lathes.The phenomenon that the center of gravity of the workpiece and the center position of the hydrostatic thrust bearing table remain coincident during the machining process is a theoretical experimental phenomenon,this is the best condition.However,in the processing of most parts,the asymmetry of the shape of the processed part,the clamping position and the cutting force will cause the center of gravity of the processed part to be not at the center of the worktable.Therefore,the occurrence of eccentric load is an inevitable problem.The occurrence of the eccentric load may cause local thinning of the oil film and increase heating deformation,and at worst,the occurrence of dry friction and friction failure.Therefore,the research on oil-cushion tilting hydrostatic thrust bearings under eccentric load conditions is of great significance.This paper studies and analyzes the selection scheme of hydrostatic thrust bearing oil supply mode,derives and calculates static and characteristic equations such as flow rate,bearing capacity,oil film thickness,and temperature rise under eccentric load conditions.Use Solid Works to establish the inclined three-dimensional oil film model of each oil cavity under eccentric load conditions,use CFD to mesh the oil film of each oil cavity under eccentric load conditions,and adopt the mesh merging method to merge the grids of all oil cavities.Then,after setting the boundary conditions in CFX,the overall oil film grid model is solved.After obtaining the pressure field and temperature field under different rotation speeds,different offset distances,and different loads,analyze the influence of rotation speed,offset distance,and load on the static characteristics of hydrostatic thrust bearings under eccentric load conditions,and use Workbench to analyze different offsets Deformation of friction pair under distance.This study derives and calculates the dynamic performance indexes of the stiffness and damping coefficient of each oil cavity under eccentric load conditions,and establishes the equivalent model and transfer function of the hydrostatic thrust bearing under eccentric load conditions.The law of oil film change under different offset distances,different loads,and different sudden loads is analyzed by MATLAB.And calculate the dynamic stiffness of the oil film under sinusoidal load,and compare and analyze the relationship between the static and dynamic stiffness of the oil film and the damping ratio.Carrying out temperature field and pressure field experiments under the working conditions of 110 rpm,load 24 t,and offset distance of 100 mm on the static and dynamic pressure test bench.Process and analyze the obtained experimental data to verify the rationality and accuracy of the simulation experiment.