Silent chain noise of cab motorcycles

In the design of driving systems, silent chains have extensively replaced roller chains thanks to annoying noise problems. But, for some types of cab-motorcycles, especially sheet-frame cabs, the annoying noise originated from silent chains can still not been accepted. In this study, silent chain noise of cab motorcycles has been well investigated by firstly the order analysis and time-frequency analysis of measured noise, and secondly the analysis of noise-origination, transmission and amplification via frame. Thus the noise mechanism can be precisely uncovered and understood. Some experiments were conducted to discover three primary issues of a noise problem, i.e., noise source, transmission path, and response. In addition, an odd mode shape, i.e. mode (1,3), was constructed based on the running mode principle. Then, a dominant noise component resulting from structure resonance can be interpreted. In the study, different engineering modifications have been validated to reduce this transmissionpart noise.