Roller Bearing Skidding for Aero-Engine Applications: All-Steel Versus Hybrid Bearings

Roller bearings operating under light loads may suffer from skidding. The latter is more pronounced as the speed increases and may result in extensive wear and reduced service life of the bearing. The main objective of this study is to analyze skidding occurrence in a custom-made all-steel M50 bearing and a hybrid roller bearing subjected to the same operating conditions. The test bearings have a bore diameter of 90 mm, an outer diameter of 125 mm and 26 rollers. The hybrid bearing features silicon nitride (Si3N4) rollers and steel rings (M50 outer ring and M50-NIL inner ring). The bearings feature special channels to allow for under race lubrication of the bearing components in relative motion. A suite of sensors were used and installed to detect skidding and monitor the overall performance of the test bearing such as vibrations and temperature. The effect of the radial applied load, shaft rotational speed, and oil flowrate on roller skidding has been investigated and discussed. Slip ratio for each of the bearings under various speed-load combinations was also determined and analyzed. Turbo-Oil 2380 was used to lubricate the test bearings at a constant temperature of 77 degrees C. Tests were conducted on a high-speed rolling bearing test rig, and data were recorded using a 24-bit data acquisition system.