Vibration Monitoring and Damage Quantification of Ball Bearings for Household Appliances

The main objective of this paper is to determine the relationship between bearing vibration/noise and the amount of flaws existed in a ball bearing assembly. In this study, 30 “good” and 30 “bad” typical ball bearings used for transmissions in household appliances are used for experimental vibration testing and measurements of flaws. While the “good” bearings are obtained form the lot of bearings tested for acceptable noisy level and the “bad” bearings are obtained from the lot with high rejection level. Although some irregularities are found in the ball elements, but most of the flaws are found in the outer races of the “bad” bearings. The levels of the flaws are measured using micrometers and vibration levels of the bearings are obtained from the accelerometers attached to the bearing supports at the bearing test rig. Time domain, frequency domain, and chaotic vibration signatures for the bearing are examined to correlate with the levels of flaws in the outer races of the bearings. The results from the FFT spectra show that the average vibration amplitude of the “bad” bearing is about 5 times higher than those of the “good” bearings.