Effect of structure and assembly constraints on temperature of high-speed angular contact ball bearings with thermal network method

摘要

The thermal performances of high-speed angular contact ball bearings have not been thoroughly addressed so far. The effect of contact angle on the thermal expansion and deformation of bearings was not fully considered. Meanwhile the influence of substructures on heat exchange, especially the assembly constraints and cooling/lubrication systems significantly impacting bearing temperature were not well characterized. Again, the heat transfer of various bearing's sub sources based on different heat generation mechanisms was seldom discussed independently. In this paper, the influence of contact angle on thermal deformation was first factored into the force equilibrium of angular contact ball bearings to calculate the bearing loads and then heat generation, and the heat generation and transfer of each sub heat source were detailed. Next, the lubricant, radial/axial structural constraints and assembly relations between parts were fully analyzed in affecting bearing temperature. The heat exchange of cooling unit was modeled and the equivalent size of coolant passage was determined to facilitate the thermal estimation. On these bases, an integrated comprehensive thermal grid model for a pair of front bearings of high-speed spindle and their surroundings was developed to forecast the temperature rise of bearings. Finally, the bearing temperature variation, for the purpose of validation, was tested and compared with the corresponding numerical solutions. As a result, the bearing temperature can be better forecasted when using the developed model.