多缸内燃机主轴承的结构振动响应分析

Structural Vibration Analysis of Multi-Cylinder Engine Main Bearings

以某 4缸柴油机为例 ,应用有限元方法在机体结构模态分析的基础上 ,对多缸内燃机曲轴各主轴承在曲轴轴颈作用力激励下的结构动力响应进行了计算 ,得到了曲轴各主轴承在不同方向上的结构振动响应曲线 ,并对其响应特征进行了分析 .对轴承结构动力响应与机体结构模态特征间的关系 ,以及主轴承结构振动与机体结构振动和噪声辐射之间的关系也做了进一步的讨论 .结果表明作用在主轴承上的径向力可以激起主轴承的轴向往复振动 ,该轴向振动传播到机体裙部并产生噪声辐射 。

On the basis of structural modal analysis,the structural dynamic responses of the main bearings of a 4 cylinder internal combustion engine,which were excited by main bearing forces,have been evaluated using finite element method.Through the analysis,the response curves in different directions of each main bearing are obtained,and further investigation is made on the characteristics of responses.And then,the correlation between the dynamic response of main bearings and the structural modal characteristics,and the dynamic coupling between the main bearings and the block as well as noise radiation also have been discussed.The results demonstrate that the axial vibration of main bearings is excited by the radial bearing forces, and this axial vibration leads to the bucking or bulging lateral vibration in block skirt,which is responsible for the noise radiation.Thus the noise radiation from the crankcase can be suppressed through controlling the axial vibration of main bearings.