Performance Analysis Of Rolling Bearing Considering Thermal Effect And Surface Defects

Bearing is the key component in equipment manufacturing industry. With the development of modern equipment to high-speed, heavy load conditions, there are increasing demands on load capacity, dynamic performance, reliability and running accuracy of bearing. Under the high-speed conditions, frictional heating greatly affects bearing clearance and lubricated contact performance. Accordingly, it’s very important to analyze dynamic performance of rolling bearing with consideration of thermal effect. In the case of high precision operating conditions, most bearing defects will have significant influence on dynamic behavior of rolling bearings as an internal incentive, which implies that systematic research on the effect of on dynamic behavior of rolling bearings is desirable in a hurry. Then we could explain the internal patterns and provide theoretical basis to improve performance of mechanical equipment.Angular contact ball bearing is modeled with the consideration of centrifugal force and gyroscopic torque under high-speed conditions, the thermal deformation of bearing component, which can obtain the contact force, contact pressure and inertia force between inner and outer raceways, and analyze the impact of thermal effect to bearing performance. The result showed that the contact force and contact pressure in outer raceway get bigger and those in inner raceway get smaller due to the thermal deformation, while thermal effect has barely impact on centrifugal force, gyroscopic torque and axial displacement of bearing. The model is further improved based on coordinate equivalence, which has high computational efficiency.For the deep groove ball bearings, the bearing differential equations of motion are established with consideration of the oil film damping and the tangential friction, which is much close to the actual working conditions and not sensitive to the initial solution guess. The displacement and speed of the inner raceway center are compared with the case without considering the effect of oil film; the effect of oil film on the bearing dynamics is investigated with the consideration of waviness and surface, which shows that the presence of the lubricant oil film tends to reduce the bearing vibration.The dynamic model of angular contact ball bearing is developed with further considering the combined effect of thermal deformation and oil film damping. The results show that, axial preload could enhance bearing stiffness, decrease vibration, but increase frictional heat, and shorten bearing life; the impact of waviness and dent on vibration of angular contact ball bearing depends on the actual conditions; thermal effect could decrease vibration, while aggravate the impact of waviness on running accuracy of bearing.