基于偏相干函数分析的曲轴箱表面振动和曲轴三维振动研究

A Study on 3D Vibration of the Crankshaft and Surface Vibration of the Crankcase based on Partial Coherence Function Analysis

研究曲轴的三维振动对曲轴箱表面振动的影响,开发了曲轴三维振动测试装置,并对曲轴的三维振动信号和曲轴箱表面振动信号进行采集和偏相干分析处理。结果发现:表面振动是曲轴三维振动共同作用导致的。其中扭振能够以倍频激励的形式出现,导致部分频率的表面振动;纵振与表面振动的总体相干水平不高,只在部分频率段具有较高的相干函数;弯曲振动与表面振动的偏相干水平较高,是表面振动的主要激励源。

For studying the effect of the 3D vibration of crankshaft on the surface vibration of crankcase, the crankshaft torsion/axial/bending vibration testing devices are developed, and the signals of crankshaft 3D vibration and the surface vibration of crankcase are measured, with the partial coherence between them analyzed. The resuits show that the surface vibration of the crankcase is induced by 3-D vibration of the crankshaft. The torsional vibration of crankshaft induces the surface vibration of crankcase at some frequencies, commonly doubling that of the torsional vibration; The degree of partial coherence between axial vibration of crankshaft and surface vibration of crankcase is not very high except at some frequencies; while the bending vibration of crankshaft has higher partial coherence with the surface vibration of crankcase and is the major excitation source of surface vibration.