Research On Temperature Distribution And Working Life Of Spindle Bearing For Precision Machine Tool

During the working process,the heat generated by friction will make the temperature of bearings rise rapidly.The rise of the temperature will have a certain impact on the structural parameters of the bearing,the working life of the bearing will also be affected.Therefore,it is necessary to study the temperature characteristics of the bearing.For the bearings used in precision machine tools,besides contact fatigue,the loss of accuracy caused by wear is also the main cause of bearing failure.Therefore,when calculating the working life of bearings,the fatigue life and wear life of bearings should be considered at the same time,and then choose a more suitable method for precision machine tool spindle bearing.This thesis takes double row cylindrical roller bearing for precision machine tools as the research object,the temperature distribution and working life of the bearing are studied.The main research content include:(1)The contact characteristic of machine tool spindle bearing is analyzed.Considering the influence of the relationship between the assembly and the bearing clearance,a quasi-static analysis model of the bearing is established.And then the influence of working condition parameters and structural parameters on the dynamic load distribution and kinematic characteristics of the bearing are studied,which provides a basis for the subsequent friction and heat analysis.(2)The internal friction source of bearing is described in detail,and the spindle bearing frictional heat generation calculation model is established using the overall method and the local method respectively.The calculation results of the two methods are compared and analyzed.More appropriate method for precision machine tool spindle bearings is obtained.And then the effects of different working conditions,structural parameters and lubrication parameters on frictional heat generation are studied.(3)Based on the calculation of frictional heat generation,through the analysis of the heat transfer relationship in the spindle-bearing system.The thermal impedance value of each part is determined,the thermal network analysis model including thermal deformation is established,the temperature distribution of the bearing is obtained.Subsequently,the change trend of the steady-state temperature of the bearing under different working conditions and lubrication parameters are studied.(4)Based on the effect of temperature on the structural parameters of bearings.First,the fatigue life of the bearing is obtained according to the L-P rating life calculation theory.Second,based on the analysis of the wear characteristics of the spindle bearing,the bearing wear life calculation model is established,the fatigue life and wear life of the bearing under specific working conditions are calculated.Finally,a platform for predicting the working life of the spindle bearing is built through MATLAB,which provides convenience for the rapid calculation of bearing life.