Studies on Rolling Sound : 3rd Report, Generation Mechanism of Sound

Abstract

Rolling motion is one cause of mechanical sound. Rolling sound may cause serious problems when it is excessive in machines and structures, for example. A series of studies have been carried out in order to obtain basic information for the reduction of rolling sound. This third report concerns the generation mechanism of the sound. Horizontal square steel plates with different surface finishes were simply supported at four points. Nylon and steel balls with different surface finishes were rolled at various rolling velocities on the plates, and the sound was measured using a condenser microphone. Surface topographies of the balls and plates were also measured by a device measuring the deviation from circular form and surface roughness, respectively. The signals obtained in the measurements were analyzed by an FFT analyzer. From the experiments, analysis and considerations, the generation mechanism of the sound was clarified.