Research On Temperature Characteristics And Rotation Accuracy Of High Speed Angular Contact Ball Bearings

Rolling bearings are widely used because of their high load,high accuracy,low friction loss and easy start-up.They are important parts of contemporary mechanical equipment.Under high and super-high speed conditions,temperature and vibration in rolling bearings interact and couple with each other.The induced vibration directly affects the rotational accuracy of the equipment,and its temperature rise also restricts the service performance and service life.Therefore,it is a general trend to analyze the internal coupling relationship of bearings and establish an accurate coupling dynamic bearing analysis model.However,the dynamic model involves the cross-coupling of multi-disciplinary fields,and there are some difficulties such as the different nature of the model and the complex coupling relationship.Therefore,a fulldegree-of-freedom dynamic model of angular contact ball bearings with fixed outer rings and rotating inner rings is established in this paper.A thermo-mechanical coupling dynamic model of bearings is established by combining the transient thermal network method.The effects of working conditions and structural parameters of bearings on contact load,rotating accuracy and temperature characteristics of bearings are analyzed from the angle of bearing structure design.Based on Matlab platform,the analysis and calculation software of high-speed angular contact ball bearing is developed.Specific research contents are as follows:(1)In order to improve the accuracy of dynamic model analysis,based on Gupta fulldegree-of-freedom model and Hertz contact theory and elastohydrodynamic lubrication theory,a dynamic analysis model of 5-degree-of-freedom inner ring,6-degree-of-freedom ball and 6-degree-of-freedom cage was established for angular contact ball bearings with fixed outer ring and rotating inner ring.It provides a theoretical tool for the analysis of bearing motion and force characteristics.(2)In order to study the temperature characteristics of high-speed bearings,this paper derives the transient thermal network analysis model of bearings by using the steady-state thermal network method.Combining with the dynamic analysis model of bearings,considering the thermal-motion,thermal-deformation and thermal-lubrication coupling relationship of bearings,a real-time reconstructed thermal-mechanical coupling dynamic analysis model of bearings is established.The results of the dynamic model and thermo-mechanical coupling model are compared and analyzed.It is found that the thermal effect has nearly 22% and 30% effects on the contact load and centroid displacement of high-speed precision bearings,respectively.The necessity of considering thermal effect in performance analysis of high-speed precision bearings is verified.(3)Based on thermo-mechanical coupled dynamic model,the effects of working conditions and structural parameters on contact load,inner ring rotation accuracy and bearing temperature characteristics were studied.It is found that the influence of rotational speed on contact load of bearing is the most obvious,followed by load and number of balls;the influence of rotational speed,load,number of balls,clearance and curvature coefficient on radial runout and maximum centroid displacement of bearing is more obvious;the influence of rotational speed on temperature rise of bearing is the most obvious,followed by load and number of balls,which is similar to that of contact load.(4)Based on the thermo-mechanical coupling dynamic analysis model,the background algorithm and the human-computer interaction interface are compiled with MATLAB platform,and a high-speed angular contact ball bearing analysis software is formed for the digital analysis and design of high-speed bearings.