Investigation on internal air flow pattern of angular contact ball bearing with different cage guiding approaches

Abstract

In condition of high rotation speed, air vortexes and high pressure air blocks will be induced by the enhanced air flow inside the rolling bearing cavity, which will have strong effect on the oil-air transportation and lubrication performance of the ball bearings. For angular contact ball bearing at ultra high speed (dmn≥2.0×106 mm·r·min-1), the air flow pattern is investigated in consideration of structure characteristics, contact feature and motion boundary. The rotating coordinate system is employed to denote bearing subassembly motions thus a high precise numerical model is achieved. The air pressure and temperature distribution, air flow pattern and resistance are discussed for different cage guiding approaches. Air flow and heat transfer performance, are evaluated via field synergy principle, especially for the key contact and lubrication areas. The results show that air pressure dramatically increases at ultra high rotation speed. The maximums of internal flow velocity, resistance, synergy angle and dynamic pressure around the ball occur under outer ring guiding condition. When the rotating speed is higher than 3.0×104 r·min-1, new vortex appears near the entrance of inner raceway contact area, which induces the increase of synergy angle and the decline of flow performance.