In order to explore the variation of oil churning loss of deep groove ball bearing with oil injection lubrication conditions and improve the performance of gearbox integrated transmission system,the numerical calculation model of deep groove ball bearing under oil injection lubrication was established and verified by SKF model.By using the method of numerical simulation and orthogonal design,the motion state of the internal flow field of the deep groove ball bearing under oil injection lubrication,and the churning loss of the deep groove ball bearing under oil injection lubrication under different working conditions were studied.The influence of various factors on bearing oil mixing loss was determined through range analysis and variance analysis.The results show that the during the process of oil injection lubrication,the volume fraction of lubricating oil on the surface of outer ring continuously increases with the injection of lubricating oil and gradually tends to be uniform and stable,while the volume fraction of lubricating oil on the surface of inner ring is always very low.The nozzle angle has a significant impact on the internal lubrication and oil stirring power loss of the bearing.When the nozzle is facing the outer ring,the oil stirring torque is the smallest,but the lubrication performance is poor.When the nozzle is facing the inner ring,the lubrication performance is the best,but the oil stirring torque is slightly larger.The influence of various factors on the bearing oil churning loss is in the order of pitch diameter,rotational speed,injection pressure,nozzle diameter and temperature.The research results provide an important theoretical reference for exploring the oil injection lubrication mechanism of deep groove ball bearings and improving the transmission efficiency of vehicles.