Yang Yang / China North Vehicle Research Institute
Assembly errors, including gear center distance variation and misalignment, are main sources of damage and vibration of gear system. Gear modification is considered to be an effective way to improve meshing state and reduce vibration impact. In order to investigate the influences of gear center distance variation, misalignment and gear tooth modification on the vibration characteristics of gear systems, the dynamic model of multi-stage gear transmission system is established in this paper. An improved loaded tooth contact analysis (LTCA) method is presented to analyze meshing characteristics of gear pairs. The time-varying meshing stiffness (TVMS) and transmission error (TE) of gears are calculated considering center distance variation, misalignment and tooth modification that are introduced as tooth profile deviation. The accuracy and efficiency of the proposed method are verified by comparing with the results obtained form the MASTA software. Then, TVMS and TE are introduced into the dynamic model as internal excitation, and the vibration characteristics of the system under different rotational speed and torque are studied. The results show that center distance variation and misalignment have a significant effect on TVMS, TE and contact patterns. Appropriate tip relief and lead crowning can decrease the tooth interference and reduce the system vibration and noise. In addition, lead crowning has the effect of reducing the concentration of load due to misalignment, so that the meshing process is stable and the load is evenly distributed along the tooth direction.