柴油机配气挺柱运动学及应力分析

Tappet Kinematics and Stress Analysis of Diesel Engine Valve

针对某型号柴油机的配气挺柱,计算其在额定工况下的速度和加速度曲线.采用多体动力学方法,结合Hertz理论和有限元分析方法,确定挺柱在怠速工况和额定工况下的最大Von Mises等效应力值和危险位置.结果表明,挺柱在工作中的危险位置在挺柱颈部,应力集中处的应力值大约是柱身应力值的3倍.针对挺柱在设计中未考虑到的问题,对挺柱的结构在允许的范围内加以优化,使应力能够较为均匀的分布在挺柱上.在相同条件下进行对比模拟后发现,新结构能够有效改进挺柱应力集中问题,从而增加挺柱寿命.

For a type of gas column of diesel engine, the speed and acceleration curves in the rated condition are calculated. With the multi-body dynamics method, Hertz theory and finite element analysis, the stress, the shear stress and the dangerous position of Von Mises are determined in the idle condition and the rated condition. The dangerous position of the tappet is in the neck, the stress value in stress concentration condition is about 3 times as the stress value of the column body. For the problem that never eonsidered in the design, the structure of the column is optimized, so that the stress would be distributed on the column. The new structure improves the stress con- centration of the column effectively, and the service life of the column is increased.