Research On Cnc Milling Spindle Bearing Oil-air Lubrication

As a core component of CNC milling spindle bearing, milling processing efficiency andaccuracy has been affected by temperature conditions. To make the bearing temperature islow and better work, bearing temperature rise is tightly controled, bearing lubrication isparticularly important. Oil-air lubrication as a new type of lubrication, rolling bearings isimpacted by it. The research of bearing lubrication has important practical significance forthe development of high-speed machining technology.In this paper, CNC milling LXK300X of angular contact ball bearings is studied by acombination of theoretical analysis and experimental methods, mainly for oil-airlubrication mechanism and oil-air lubrication of the bearing temperature rise.The development trend of domestic and foreign oil-air lubrication and applications isstudied. Through the study of elastic hydrodynamic lubrication and oil-air lubricationprinciples, bearing lubrication is theoretically analyzed,and the advantages of oillubrication is summed up. Oil-air lubrication film thickness formula is draw up by theapplication of film thickness classic formula and oil-air lubrication mechanism.In this paper, the mechanism of bearing friction heat is analyzed, the influence offriction on bearing temperature is drew on. And it is calculated by using the classic formulaof the friction torque and heat. Based on the theory of heat transfer, thermal resistanceformulas is derived for the various parts of the bearing.Bearing on the heat transfer process can be simplified, according to bearingone-dimensional model of heat transfer process, bearing hot node graph and bearingthermal resistance figure are draw. After the heat transfer of bearing is analyed usingthermal resistance network method, heat transfer equation bearing unit is built. Andbearing temperature rise using oil-air lubrication is theoretically proved lower than oillubrication.The temperature of the bearing is affect by the speed, amount of lubricating oil,lubricating oil kinematic viscosity, air pressure in oil-air lubrication,mainly as follows:frictional heating of bearing is impacted by speed, volume of lubricant and lubricantkinematic viscosity, the bearing temperature rise is impacted by air pressure of theconvection heat transfer. Better lubrication and cooling effect is got by oil-air lubrication than oil lubrication.