Abstract
In order to support continuous development in silent chain design, one important parameter that has to be monitored is its noise. In order to perform noise measurement, a tailor-made test rig is needed. In this research work, an existing silent chain elongation test rig is converted into noise measurement test rig. The elongation test rig is supplied by PT. FSCM Mfg. Indonesia. After performing standard procedure, the third design is finally selected from three design alternatives. The prototype was manufactured in the workshop of Mechanics and Mechanical Construction Laboratory, Institut Teknologi Bandung (ITB). The test rig consisted of an insulated section, microphone, electric motor, and inverter (to adjust the rotational speed), belt transmission, and frame. The data acquisition system consisted of soundcard and a freeware data logging software. Data processing was performed using the software Freemat. In this case, the .wav file is processed using FFT to obtain the power spectra. The analysis showed that dominant noise signals in the power spectra matched the meshing frequency of the chain transmission. In addition, the spectra also showed sidebands at chain running speed frequency. It is thus concluded that the acoustic signal posses the same characteristics as the vibration signal. Based on this result, we recommend the utilization of the test rig in optimizing silent chain design.
Keywords: silent chain, cam chain, test rig, sound measurement, spectral analysis