三缸柴油机曲轴动平衡仿真分析研究

Simulation Analysis on Dynamic Balancing for Crankshaft of a Three Cylinder Diesel Engine

利用Pro/E和Adams创建某三缸柴油机曲轴的刚性体模型和柔性体模型。运用快速傅立叶变换得到各主轴颈承受的动态载荷、频谱曲线和积分曲线,通过各种频率下的振幅判断整机的平衡性能。研究发现,在X方向上(纵向),不同的一级往复惯性力矩转移率对曲轴主轴铰链副的振动幅度影响不大;在Y方向上(横向),从频域信号中发现,不同的一级往复惯性力矩转移率在同一频率达到最大值,并且随着一级往复惯性力矩转移率的减小,其均方根随之减小;在Z方向上(横向),不同的一级往复惯性力矩转移率对曲轴主轴铰链副的频谱曲线中二阶频率振动影响很小。不同的一级往复惯性力矩转移率中,曲轴各主轴颈上合力的最大值、平均值和均方根的变化趋势不一样,其中均方根RMS能最全面地反映振动力度。

A rigid body model and a flexible body model for a crankshaft of a three cylinder diesel engine were established by using Pro/E and Adams.The dynamic loads,spectral curves and integral curves of each spindle neck were obtained by using fast Fourier transformation,and the balance performance of the whole machine was judged by the amplitude of various frequencies.In X direction(longitudinal),it is found that different first-order reciprocating inertia moment transfer ratio has little influence on the vibration amplitude of the crankshaft spindle hinge pairs.In Y direction(transverse),it is found that from the frequency domain signal,different transfer rate of the first order reciprocating inertia moment reaches the maximum at the same frequency,and the root mean square decreases with the decrease of the transfer rate of the reciprocating inertial moment.In Z direction(transverse),the different first-order reciprocating inertia moment transfer rate has little influence on the two-order frequency vibration of the crankshaft main shaft hinge pairs.In different first-order reciprocating inertia moment transfer rate,the variation trends of maximum,mean and root mean square of resultant forces on crankshaft main journals are different.Among them,the root mean square(RMS) can reflect the vibration strength most comprehensively.