Study On Morphology Of Oil Film In Static And Dynamic Pressure Mixed Support

With the advancement of the "Made in China 2025" process,higher requirements have been placed on the carrying capacity and accuracy of heavy-duty CNC equipment.The hydrostatic bearing,which is the core supporting component of heavy-duty CNC equipment,operates under high-speed and heavy-load conditions.The gap lubricant film is subjected to a combination of strong extrusion force and strong shear force.The temperature of the lubricant increases and the viscosity Falling,the oil film becomes thin,and boundary lubrication or dry friction begins to form locally,and then tribological failure will occur.In order to avoid the occurrence of tribological failure,a new type of static and dynamic pressure mixed support oil pad structure is proposed in this paper,which realizes the mixed lubrication of static pressure and dynamic pressure,and achieves the effect of preventing friction failure.In order to achieve better lubricating effect and running accuracy of the static and dynamic pressure mixed bearings,the paper mainly studies the morphology of the gap oil film which directly affects the oil flow and the rotation accuracy of the turntable.Design a new type of static and dynamic pressure mixed support oil pad structure.The bottom of the oil pad and the base adopt pin connection and clearance fit.During its operation,the oil pad tilts,forming a dynamic pressure effect,and compensating for the static pressure loss.Based on the theory of static and dynamic pressure lubrication and fluid dynamics,a mathematical model for theoretical analysis of the oil film of the static and dynamic pressure mixed bearing gap is established.The three-dimensional geometric model of the bearing is established using Creo three-dimensional software.And high-quality structured meshing of interstitial oil film is established using ICEM-CFD software.The specific parameters and corresponding boundary conditions required for the simulation calculation of the lubrication performance ofthe gap oil film were determined,and the CEL statement of the viscosity-temperature relationship of No.46 lubricant used was written.Under different extreme working conditions,CFX was used to simulate the fluid with variable viscosity in the interstitial oil film,and the pressure and temperature field simulation cloud maps of the oil film under the corresponding working conditions were obtained.The simulation results provided the prerequisites for the next step of thermal-coupling simulation analysis.Based on tribology,thermodynamic finite element analysis,elastoplastic deformation theory,and heat transfer,ANSYS 15.0 Workbench software is used to perform a thermo-mechanical coupling simulation analysis on the static and dynamic pressure mixed support friction pairs,and the deformation field corresponding to each working condition is obtained.The deformation field data was extracted and imported into Matlab for data processing to obtain the three-dimensional topography of the oil film.An experimental platform was set up to test the actual morphology of the oil film under the mixed conditions of static and dynamic pressure under extreme conditions,and the theoretical analysis and simulation were verified.