The work presented in this paper outlines the design and development of a new roller chain sprocket tooth form for engine camshaft drives in an effort to reduce the noise levels related to chain-sprocket meshing. The crankshaft sprocket also incorporated inclined plane Nitrile damper rings to further reduce meshing impact noise levels. Previous experimental studies have shown that roller impact during meshing is a dominant noise source in roller chain drives.
Noise evaluations were conducted for several camshaft drive configurations on a 4-cylinder DOHC automotive engine in a semi-anechoic dynamometer facility. The tests included measurements of meshing frequency sound power levels and overall sound power levels.
This firing engine noise and vibration experiment was done to compare the noise levels of the asymmetrical sprocket tooth profile to that of a standard ISO sprocket tooth profile. The results show the random-asymmetric tooth profile to reduce the meshing frequency noise levels compared to the symmetrical ISO tooth form sprocket for the chain drive system evaluated.