| 摘要 |
PROBLEM TO BE SOLVED: To provide a new procedure for specifying a belt slip sound caused by micro-vibration in the pulley radial direction generated by misalignment or the like, and elucidating its sound production mechanism. SOLUTION: Laser light transmitted from an optical Doppler vibration measuring device 3 is reflected by a belt back face vibrating in the pulley radial direction, and receives a Doppler shift. The reflected light is allowed to optically interferes with reference laser light, to be thereby converted into a voltage signal. The FM modulated wave is recorded as a vibration speed signal proportional to the Doppler shift by an optical heterodyne detection demodulation unit. Simultaneously, a noise level signal is recorded as time series data by a microphone 4 provided near the laser light irradiation position. The sound production time is specified from agreement of peaks of a pair of waveforms, and a coherence function is operated from a frequency spectrum of the pair of waveforms, and the sound production frequency is specified by using the coherent value as a determination standard value. COPYRIGHT: (C)2004,JPO&NCIPI
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