Sensitivity of Air-Coupled Ultrasound and Eddy Current Sensors to Bearing Fault Detection

Abstract

For decades, vibration and oil analysis have usually been used to detect early bearing faults and track their progression over time. Progress has been seen in condition monitoring through vibration analysis of rolling element bearings using improved sensors and advanced signal processing techniques. In this paper, the authors investigate the use of air-coupled ultrasound and eddy current sensors as diagnostic tools for the detection of bearing faults. A series of experiments was carried out in a laboratory environment: localized defects with different sizes were created intentionally on the test bearing components simulating evolving cracks or other related faults. The resulting data for a constant bearing speed and load have shown that both sensors are capable of detecting different types of defects located on the bearing components. The data from the air-coupled ultrasound and eddy current sensors were also compared with those obtained from an accelerometer. The test method and the processing technique are described and the spectra of the different signals are analyzed and discussed.

KEY WORDS:

• Ball Bearing
• Air-Coupled Ultrasound Sensor
• Eddy Current Sensor
• Envelope Detection

Acknowledgments

Presented at the STLE annual meeting in Philadelphia, Pennsylvania May 6-10, 2007