The application of the sound-intensity technique to defect detection in rolling-element bearings

Abstract

The two-microphone sound-intensity technique has been used for the detection of defects in radially loaded ball bearings. The difference in the sound-intensity levels measured for bearings with no defect and for those with intentionally introduced defects of different sizes in their elements under various operating conditions of loads and speeds is demonstrated. A change in the intensity frequency spectrum because of the defects is observed. The results show that the detectability of an outer-race defect is much better than that of an inner-race or ball defect. It is difficult to detect defects at lower speeds. Sound-pressure measurements were also performed for comparison, and it is shown that the detectability of defects by sound-intensity measurements is better than that by sound-pressure measurements.