柴油机正时齿轮系动力学特性分析

Dynamic characteristic analysis of diesel timing gear trains

为了分析柴油机正时齿轮系的动力学特性以及对前端噪声的影响,建立正时齿轮系的多体动力学模型.分析考虑各齿轮负载及曲轴角速度波动时的齿轮扭转角位移、啮合齿对相对运动以及动态啮合力,并对比了不考虑曲轴角速度波动时的计算结果.结果表明,由曲轴扭振引起的角速度波动能够明显加大齿轮系的振动与冲击.凸轮轴齿轮扭转角位移的实验结果与计算结果较为一致.前端声强实验表明在1 000Hz以下,齿轮系动态特性对噪声影响较大,高频处由齿轮加工精度影响的传递误差引起的噪声较大.通过设计曲轴扭振减振器,可以改善齿轮系的啮合振动与冲击,相应地减小前端的辐射噪声.

To analyze dynamic characteristic of diesel timing gear trains and whose influence on noise of engine front, muti-body dynamic model of diesel timing gear trains was established. Gear torsional angular displacement, relative motion in the tooth pair meshed and dynamic meshing force were analyzed considering gear trains loads and crankshaft angular velocity fluctuation, which were compared with that without considering crankshaft angular velocity fluctuation. Results showed that angular velocity fluctuation caused by crankshaft torsional vibration can increase vibration and shock among gear trains obviously. Test result of camshaft gear torsional angular displacement was consistent with the simulation result. Front sound intensity experiment displayed that radiated noise is mainly affected by dynamic characteristic of gear trains below 1000 Hz and by transmission error due to machining accuracy in high frequency range. Through design of crankshaft torsional vibration damper, meshing vibration and shock of gear trains can be improved and the radiated noise can be reduced correspondingly.