Dynamic, thermal, and vibrational analysis of ball bearings with over-skidding behavior

The term“over-skidding”indicates that the cage rotational speed ratio exceeds the theoretical value as ball purely rolls on the raceway.Different from the skidding phenomenon that occurs in low-load and high-speed bearing,over-skidding usually occurs in large-size angular contact bearings,and it is still difficult to suppress under high load conditions.The main forms of damage to the raceway by over-skidding are spinning and gyro slip.To further explore the vibration characteristics and thermal effects of this phenomenon,a set of over-skidding tests of an angular contact bearing with a bore diameter of 220 mm were conducted on an industrial-size test bench.Through the experiment,the influence of axial load,rotational speed,and lubrication conditions on the occurrence of over-skidding were determined.Based on a previous dynamics model,the heat generation and thermal network models were integrated in the present study to predict the over-skidding and its thermal behavior.The model was validated in terms of the measured degree of over-skidding and temperature rise.The results showed that the degree of over-skidding reaches up to 12%of the theoretical value,and the friction power loss of the ball-pocket accounts for 30%of the total power loss.The analysis of the vibration signal showed a strong correlation between the bearing vibration characteristics and over-skidding behavior,thereby providing a way to indirectly measure the degree of over-skidding.