摘要
综合考虑轴承支承刚度、轴段摩擦状况、曲轴转速波动及缸内爆发压力的影响,建立某凸轮轴动力学模型。基于该模型进行凸轮轴三维瞬态动力学及疲劳安全分析,结果显示凸轮轴最大应力点出现在第1缸轴段的圆角位置,最小疲劳安全系数为3.094。将原瞬态动力学模型的计算结果与不考虑曲轴转速波动时的结果进行比较表明,转速波动的存在可以改变凸轮轴瞬态的动力学状态,在气门全开位置时最大应力点峰值普遍偏小且发动机基频第2阶次对该处应力幅值影响较大。
A camshaft dynamic model is built with consideration of bearing support stiffness, friction, crankshaft speed fluctuation and cylinder explosion pressure. 3D analysis of camshaft transient dynamics and fatigue safety is made based on this model, the results show that the camshaft＇s maximum stress appears at the rounded corner of the first cylinder and the minimum fatigue safety factor is 3.094. Meanwhile the calculation results with the original transient dynamic model are compared with the calculation without consideration f crankshaft speed fluctuation, which show that speed fluctuation can change transient dynamics state of the camshaft, and the maximum stress peak is generally small when throttle valves are fully open, and engine＇s 2nd order of basic frequency has substantial influence on the stress amplitude.
出处
《汽车技术》
北大核心
2014年第5期25-29,共5页
Automobile Technology
关键词
凸轮轴
瞬态动力学
疲劳分析
转速波动
Camshaft
Transient dynamics
Fatigue analysis
Speed fluctuation
