主轴承表面型线对曲轴润滑与振动特性的影响

Effect of Main Bearing Surface Profile on Crankshaft Lubrication and Vibration Characteristic

以某六缸柴油机主轴承-主轴颈为研究对象,基于弹性流体润滑理论和微凸峰接触理论,考虑轴颈倾斜和主轴承表面粗糙度等因素,建立柔性整机体下的主轴承润滑特性模型,分析了主轴承表面型线对主轴承润滑特性与主轴颈振动特性的影响。结果表明,相比于不计入主轴承表面型线的结果,计入主轴承表面型线时,主轴承的最小油膜厚度增加了75.53%,最大油膜压力减小了6.15%,平均摩擦损失降低了2%,主轴颈的水平弯曲振动幅值减小了6%,竖直弯曲振动幅值减小了5%,轴向振动和扭转振动幅值均减小了2%。随着主轴承表面型线高度的增加,主轴承的最小油膜厚度增加,最大油膜压力减小,平均摩擦损失降低,最大粗糙接触压力的幅值和出现次数均降低;主轴颈的弯曲振动、轴向振动和扭转振动幅值均减小。

Taking the main bearing-main journal of a six-cylinder diesel engine as the research object,based on the elastic--fluid lubrication theory and the micro-bump contact theory and considering factors such as journal misalignment and main bearing surface roughness,the main bearing lubrication characteristics model under the flexible whole body is established,and the influence of the main bearing surface profile on the main bearing lubrication characteristics and main journal vibration characteristics is analyzed.The results show that,compared with the result that does not take into account the main bearing surface profile,when the main bearing surface profile is included,the minimum oil film thickness of the main bearing is increased by 75.53%,the maximum oil film pressure is reduced by 6.15%,the average friction loss is reduced by 2%,the horizontal flexural vibration amplitudes of the main journal is reduced by 6%,the vertical flexural vibration amplitudes is reduced by 5%,and both the axial vibration and torsional vibration amplitudes are reduced by 2%.With the increase of the main bearing surface profile height,the minimum oil film thickness of the main bearing increases,the maximum oil film pressure decreases,the average friction loss decreases,and both the maximum roughness contact force amplitude and the number of occurrences are reduced;the amplitudes of flexural vibration,axial vibration and torsional vibration of the main journal are all reduced.