Studies on Vibration and Sound of Defective Rolling Bearings : Third Report, Vibration of Ball Bearing with Multiple Defects

An investigation was undertaken with a view to establishing a procedure for diagnosing the extent of rolling bearing defects from their vibration and sound. In the investigation the vibration of a ball bearing with multiple dents on the race surface of either the inner or outer ring was studied. The inner ring of the bearing was caused to rotate at a constant speed under a given thrust load applied to the outer ring. The radial vibration velocity of the outer ring was determined by a moving coil type converter and using the output so obtained, vibration waveforms were produced. Real time frequency analysis of the vibrations was done by Fast Fourier Transform analyzer and the effect of the measuring position of the outer ring on the vibration, etc. was examined. As a result, the fundamental characteristics of ball bearings having multiple defects were clarified, and an effective method by which to locate the defects and to determine their number and size was established.