Evaluation of the Running Status of Ball Bearings Using Ultrasonic Signals

Rolling bearings are key components of rotation machinery, and their failure will result in severe consequences. The lubricating film is important for the normal function of rolling bearings and can be used as a sensitive indicator of the running status of the bearing. The ultrasonic detection method can directly monitor the lubricant film state of the bearing, leading to its capacity of finding the abnormality of rolling bearings at the earliest. This paper presents an attempt to monitor the running status of ball bearings using ultrasonic signals. First, the ultrasonic reflection coefficient method based on the spring model is applied to indicate the lubricant film distribution of the ball bearing. Then, under ultrasonic monitoring, a series of experiments are conducted on the test ball bearing with varying operational parameters and different degrees of pitting fault. Finally, the corresponding relationship between the ultrasound-indicated lubricant film distribution and the running status of the bearing is explored. The experimental results suggest that the processed ultrasonic signal has good consistency with the changes in the lubricating status of the bearing, as well as achieving the sensitive detection of pitting fault.