Abstract: The grille exhibited a serious jitter problem during the prototype test of a fan, after testing, the vibration reached -5.1 dB, which was much higher than the target value of -12 dB. A systematic study of the jitter problem of a fan from the aspects of excitation source, transmission path and response, and carries out the modal and vibration transfer function of the head and grille of the fan through combination of simulation and experiment. The analysis and benchmarking of the fan clarified the mode frequency of structure to avoid first-order rotation fundamental frequency of the fan speed. By designing two different vibration isolation methods for the motor and the grille, the vibration of the whole machine is reduce to -17.1 dB, which perfectly solves the problem of jitter.

Key words: Grille, Jitter, Frequency avoidance, Vibration isolation