Study On Optimal Design Of Lubrication Performance Of Hydrostatic And Hydrostatic Sliding Bearings For Machining Center Spindle

The rise of modern industry has brought great development and challenges to the machinery manufacturing industry.The manufacturing industry of various countries has a higher demand for the production efficiency and manufacturing scope of machinery manufacturing equipment.Motorized spindles have always occupied a core position in the parts of rotating machinery equipment.As the key parts of motorized spindles,the hydrostatic sliding bearing directly affects the stability and reliability of motorized spindles.So this topic to the sliding bearing of dynamic and static pressure of motorized spindle as the research object,using the CFD numerical simulation combined with experiment method,in order to enhance the stability and reliability of the electric spindle as the goal,the static pressure of the sliding bearing lubrication performance,in-depth study for the optimization of dynamic and static pressure sliding bearing lubrication performance provide theoretical guidance.The main research contents and conclusions are as follows:(1)Establishment of finite element model of hydrostatic sliding bearingBased on the basic analysis theory of CFD and dynamic pressure lubrication theory,the numerical simulation model of Fluent was established.Considering the viscosity-temperature effect of lubricating oil,the mesh generation mode,boundary conditions and calculation method were determined.The reliability and accuracy of the numerical simulation of Fluent were verified by comparing with the experimental results in literature.(2)Influence of oil cavity shape on bearing capacity and temperature of hydrostatic plain bearingThe lubrication performance of hydrostatic sliding bearing with rectangular oil cavity was studied,and the variation law of oil film bearing capacity and temperature with rotating speed and oil supply pressure was obtained.Under the condition of the same radial projection area,an optimization scheme was proposed to optimize the rectangular oil cavity into trapezoidal oil cavity.The results show that the bearing capacity of trapezoidal oil cavity is increased by about 8% compared with rectangular oil cavity,and the peak temperature of oil film is decreased by about 5% under certain bearing speed.In order to solve the problem that the peak value of oil film temperature is too high when the trapezoidal oil cavity bearing is reversed,a hexagon oil cavity is proposed.The results show that the hexagon oil cavity can effectively solve the problem of the oil film temperature peak is too high when the trapezoidal oil cavity bearing is reversed.(3)Effect of surface texture on bearing capacity and friction and wear of hydrostatic plain bearingThe effect of surface micro-pit texture on the bearing capacity of oil film is studied.The results show that surface micro-pit texture can effectively improve the bearing capacity of oil film,and the best effect is when it is arranged at the exit of the convergence zone of oil film.The analysis of circular,diamond and oval surface micro-pit texture shows that when the long axis of oval surface micro-pit texture is perpendicular to the rotation direction of bearing(90° arrangement),the bearing capacity of oil film is improved by 16.21% compared with that of non-surface micro-pit texture.The accuracy of numerical simulation is verified by friction and wear experiments.The oval surface micro-concave texture was combined with the hexagonal oil cavity structure,and the composite structure was designed on the hydrostatic sliding bearing.The performance of oil film bearing capacity and temperature under the composite structure was studied.The results show that the bearing capacity of oil film is increased by about 17.45%,and the peak temperature of oil film is decreased by about 4.78%.Through the above optimization,the purpose of improving the stability and reliability of the motorized spindle is achieved.