Abstract: The rattling model of a one-stage gear system is established, in which mass unbalance, speed fluctuation of driving shaft and backlash of the gear pair is considered. The rattling model has three degrees of freedom, one rotation and two translations in engaging line direction of the gear pair. The mapping equations of the system between impact are developed. According to the calculation results at given parameters, the rattling period of the system is related to inspiring period. At some speed of driving shaft, the rattling period is equal to that of driving shaft, at another speed, the rattling period is double. In the rattling state, impact and normal engagement between the gear pair occurs alternatively.

Key words: Speed fluctuation, Gear Mass unbalance, Mapping, Rattling model