曲轴转速波动对某柴油机正时齿轮系动力学特性的影响

Effects of crankshaft speed fluctuation on timing gear system dynamics of diesel engine

为了研究曲轴转速波动对正时齿轮动力学性能的影响,分别建立曲轴动力学模型与正时齿轮系动力学模型,在测试的基础上,研究了齿轮啮合冲击力随转速波动的变化规律,以及曲轴加装减振器前后的齿轮系冲击力与频域啮合力的变化。研究表明:随着转速的增加,转速的波动幅度增大,齿轮的最大冲击力增大,转速从1 000 r/m到3 000 r/m时,曲轴齿轮所受最大冲击力增大了近5倍。曲轴加装减振器后,各个齿轮冲击力平均减小了60%。曲轴的转速波动是导致该柴油机正时齿轮受到高冲击载荷的主要原因。

The dynamics models of crankshaft and Timing gear train were established for analysing the crankshaft speed fluctuation on the timing gear dynamics performance. On the basis of test,the variation of gear meshing impact force with the ro-tate speed fluctuation was analyzed,and the variation of gear impact force and frequency-domain engaging force was compared before and after adding crankshaft vibration damper. The research result shows that the amplitude of speed fluctuation increases with the increase of the rotate speed,and the maximum impact force is increased by nearly 5 times when the diesel engine speed is increased from 1000 rpm to 3000 rpm. Each gear impact force decreased by 60% in average after installing the shock absorber on the crankshaft. The crankshaft speed fluctuation is one of the important factors affecting the timing gear dynamics characteristics of diesel engine.