Slip in Radial Cylindrical Roller Bearings and Its Influence on the Formation of White Etching Cracks

Michael Elia Aziz Dawoud

• Publisher: Shaker
• Year: 2023
• eBook ISBN: 9783844091656
• Edition: 0

Unfavorable operating conditions and inadequate radial force cause the occurrence of slip in radial Cylindrical Roller Bearings (CRBs). This can also lead to several failure mechanisms such as smearing, scuffing, spalling, and White Etching cracks (WEC) that can occur at a small percentage of the calculated bearing life.In this work, the influence of the bearing operating conditions as well as the bearing's design on the development of the roller- and the rolling set slip was studied. The rollers of the full complement bearing stall in the load-free zone and suffer from a 100% roller slip at the acceleration zone. For caged bearings, a single-part cage outperforms the two-part cages by having lower slip tendency under restricted oil flow rates. Roller-guided cages force the rollers to interact more with the rotating inner ring and show lower slip. Under moderate clearance, more rollers contribute to the load transfer leading to higher roller slip than under higher clearance levels while preloading a bearing may lead to the elimination of the slip under any operating conditions.The slip influence on the WEC formation on a CRB was studied by conducting a total of four endurance tests using a two-phase loading scheme. It was found that high-slip operating conditions are less critical for the WEC formation on both bearing rings. The very low radial force used in the low load phase would result in a low contact pressure that is not WEC-critical. Another reason is the longer regeneration time between two overrollings occurring at a high set slip. Dynamic force conditions are more critical for the stationary bearing ring. Although suffering from high set slip full complement bearings didn't show any sign of WEC failure even after testing them for more than 3400 hours.