不同平衡率对曲轴动力学特性与疲劳强度的影响研究  

Effect of different balance rates on the crankshaft’s dynamic characteristics and fatigue strength

作　　者：毕玉华[1] 王鹏[1] 张磊[1] 申立中[1] 黄粉莲[1] 刘少华[1] 代云辉 BI Yu-hua;WANG Peng;ZHANG Lei;SHEN Li-zhong;HUANG Fen-lian;LIU Shao-hua;DAI Yun-hui(Yunnan Key Laboratory of Internal Combustion Engines,Kunming University of Science and Technology,Kunming 650500;Kunming Yunnei Power Co.,Ltd.,Kunming 650500)

机构地区：[1]昆明理工大学云南省内燃机重点实验室,云南昆明650500 [2]昆明云内动力股份有限公司,云南昆明650500

出　　处：《机械设计》2021年第3期37-45,共9页Journal of Machine Design

基　　金：国家自然科学基金重点项目(51765025);云南省科技强省项目(2015AA024);云南省基础研究重点项目(2018FA030)。

摘　　要：以非道路高压共轨四缸柴油机为研究对象,通过曲轴模态试验模态仿真,验证了曲轴有限元模型的准确性;基于柔性多体动力学与弹性流体动力润滑理论,建立了轴系多体动力学仿真模型,研究了曲轴不同平衡率与不同平衡块数对额定转速工况下主轴承载荷与润滑特性、曲轴应力与疲劳强度的影响。研究结果表明:随着平衡率增加,曲轴质量增加,内弯矩减小,平均轴承力减小;随着平衡率增加,MB3最大轴承力增加,其余主轴承最大轴承力基本不变;相同平衡率下,8块平衡重比4块平衡重方案曲轴内弯矩小。从轻量化角度出发,直列四缸机曲轴可采用4块平衡重50%平衡率方案,但在设计过程中需考虑第4主轴承的优化。This article focuses on a non-road high-pressure common rail four-cylinder diesel engine. The accuracy of the crankshaft’s finite-element model is verified by means of the modal simulation and test. Based on the theories of flexible multibody dynamics and elastic hydrodynamic lubrication,the multi-body dynamic simulation model of shafting is developed. The influence of crankshaft with different balance rates and balance blocks on main bearing load,bearing lubrication characteristics,crankshaft stress,and crankshaft fatigue strength under rated conditions is explored. The results show that with the ever-increasing balance rate,the weight of the crankshaft grows,both the internal bending moment and the average main bearing load decrease.As the balance rate increases,the maximum main bearing load of MB3 increases,and those of the other main bearings basically remain unchanged. With the same balance rate,the internal bending moment of the 8-counterweight scheme is smaller than that of the 4-counterweight scheme. From the perspective of lightweight design,the scheme of 4 counterweights with the 50% balance rate can be adopted for in-line four-cylinder crankshaft,but the optimization of the 4 th main bearing needs to be taken into consideration during the design process.

关 键 词：柴油机 平衡率 轴系动力学 疲劳强度 

分 类 号：TK422[动力工程及工程热物理—动力机械及工程]