Numerical Simulation Analysis Of Bearing Splash Lubrication In Metro Gear Box

Gearbox is the core component of metro vehicle transmission system,which transmits power and torque during the running process of the vehicle.Lubrication and temperature rise of internal components must be considered during the working process.In order to study the influence of lubrication parameters on the lubrication performance of the gearbox,based on the theory of fluid dynamics,this paper describes the working principle of the lubrication system of the metro gearbox on the basis of the three-dimensional modeling.In order to study the influence of the lubrication parameters on the lubrication performance of the gearbox,the lubrication performance and temperature rise of gearbox under different working conditions were analyzed by numerical simulation.The main research contents are as follows:In order to analyze the lubrication condition inside the gearbox and arrange the oil collecting grooves in the gearbox reasonably,a two-dimensional simulation model of the lubrication flow field of the gearbox was established.VOF model is used to capture the interface of oil-gas two-phase flow in the tank,and dynamic grid technology is used to solve the distribution of lubrication flow field in the tank under Various working circumstances The results reveal that the oil immersion level of gear has no effect on the dynamic behavior of the flow field in the box,and that the flowing field’s steady-state distribution law is essentially the same.Gear turning and rotating speed have a substantial impact on the flow characteristics in the boxes,and steering has a significant impact on the flow field pressures when the rotating speed difference is minimal.In the box,there is a vortex phenomena,which has certain influence on oil movement and flow field velocity.The oil film volume fraction and temperature rise of output bearing of subway reducer under different working conditions are studied.Taking the lubrication system of tapered roller bearing of output shaft of a subway gearbox as the research object,a numerical simulation model of lubrication and temperature rise of roller bearing is established.Fluent software,VOF method and multi-reference frame model(MRF)are used to simulate the oil-gas two-phase flow in the bearing cavity.The effects of rotational speed,oil-gas velocity at the inlet and volume fraction of lubricating oil on the lubrication and temperature rise of roller bearings are studied.The simulation results show that in the low speed stage(30r/min),the lubricating oil concentrates in the upper half of the bearing,and the lubricating oil distribution is very small far away from the inlet,so the bearing will have poor lubrication when running for a long time;The temperature distribution inside the bearing is uneven,and the temperature rise increases with the increase of bearing speed.When the vehicle runs at high speed,the maximum temperature rise reaches 36.9 ℃.The simulation results of this paper provide a reference for solving the lubrication flow field analysis of gear transmission in practice,and at the same time provide help for the structural design of gearbox and lubrication of gear transmission system.