Performance Study Of Rolling Bearing-Rotor System Considering Thermal Elastohydrodynamic Lubrication And Software Realization

A rolling bearing–rotor system is widely used in various mechanical transmission systems.In the past years,the tribological and dynamic performances of the rolling bearing-rotor system have been carried out separately.In order to deeply study the tribological and dynamic performances of such a system,the said performances should be studied from a systematic aspect and the impact of thermal elasto-hydrodynamic lubrication(TEHL)of the rolling bearing should be considered.Sponsored by the project of National Natural Science Foundation of China(No: 51775067),"Study on multi-body lubrication and thermal characteristics of high speed rolling bearing considering rotor dynamics performance",the coupling research and software realization on the tribological and dynamic performances of the rolling bearing-rotor system are carried out.The present research is eager to provide a theoretical reference and analytical means to improve the system performances.The main works of this paper are as follows:Firstly,the dynamic model of the rolling bearing-rotor system considering film force is established.Based on the radial basis function neural network,a method to predict the oil film force is proposed to accelerate the solution of the model.Based on software MATLAB,the dynamic simulation module of the system is built.The module is coupled with the radial basis function neural network module to realize the analysis and solution of the tribological and dynamic performances of the system.Secondly,based on the built dynamic model of the rolling bearing-rotor system considering film force,the coupling tribological and dynamic performances of the system is studied.The simulation shows that the minimum film thickness,the central film thickness,the maximum film pressure and the maximum film temperature all have inflection points in the process of the system vibration under abrupt load excitation,and the position of inflection point is related to the influence of transient term in the lubrication equation.In addition,the annular structure occurs in the trait of lubrication parameters varying with radial vibration displacement.The coverage of the annular structure decreases with the increase of the radial stiffness of the rotor,and increases with the increase of the radial load or the rotor’s eccentricity.The shape of the annular structure becomes sparse with increasing radial damping,and approaches to a steady value with increasing rotor speed.Moreover,with the increase of the rotor speed,the amplitude of the radial vibration displacement,torsional vibration displacement and the time for the stabilized system increase,while the frictional force of the lubrication film decreases.The increase of the roller number will lead to a reduction in the radial vibration displacement amplitude and frictional force,and an increase in the system vibration frequency.Thirdly,based on the genetic algorithm and multi-objective optimization theory,with the objective of minimizing the radial vibration displacement amplitude,film temperature and film friction,and taking the geometric parameters of the bearing,system operating conditions and lubricant parameters as optimized parameters,a collaborative optimization model for the tribological and dynamic performances of the rolling bearingrotor system is established.Compared with previous optimization dealing of the rolling bearing-rotor system,the present model takes into account the influence of TEHL,and can accurately optimize the tribological performances.In addition,to improve the optimization efficiency,a step-by-step optimization method of optimizing main influencing parameters is proposed,and the multi-objective optimization is transformed into the single-objective optimization.Through the above treatment,the maximum radial vibration displacement,film temperature and film friction can be reduced significantly.Finally,based on the mixed programming of VB and Fortran languages,a software for the performances and optimization analysis of the rolling bearing–rotor system is developed.The software is composed of two modules,which are used separately for the performance analysis and optimization design of the rolling bearing–rotor system with the TEHL consideration.It has functions such as numerical solution,data export and graphic viewing.It has been employed in the relevant institutions.