Investigation of sound signal for ball bearing monitoring based on various tolerance fits

This paper aims to investigate sound signal for ball bearing monitoring based on various tolerance fits. The experiment used a condenser microphone for sound signal detection and FFT method for sound signal analysis. The tolerance fits including clearance fit, transition fit and interference fit were determined for assembly of normal and damaged ball bearing No. 6204 to shaft and housing. The experiments were performed in 3×3 factorial of each bearing type with constant rotation at 1,450 rpm and 100% of an applied load. The results exhibited that tolerance fits slightly affected to sound signal patterns and ball bearing conditions is a major cause of sound signal amplitude increasing. In a normal ball bearing, the sound intensity increased when tolerance fit limit value of inner ring and shaft increased. However, the outer ring of a normal ball bearing must be inserted into housing with interference fit.