本文以材料由球墨铸铁替换非调质钢的 GN16 发动机曲轴为研究对象，对替 换后球铁材料的曲轴进行结构分析、工艺分析并进行试验验证。 本文根据发动机运动学、动力学、平衡性、流体润滑理论及扭转振动理论， 建立了直列四缸四冲程发动机曲轴系有限元模型，利用非线性多体动力学软件 AVL/Excite 建立曲轴系的多体动力学模型。根据疲劳分析理论、强迫振动的系统 动力学方程及 Reynolds 方程，分别对曲轴系的自由模态、主轴承载荷、危险转速 的应力和疲劳安全因子及其分布、不同材料疲劳极限下的最小疲劳安全因子方面 进行动力学疲劳结果分析，对曲轴系的一阶及二阶扭转固有频率、减振器合成扭 振振幅、单阶扭振振幅、减振器耗散功和转速波动方面进行一维扭振方面的分析， 对曲轴系的主轴瓦、连杆轴瓦进行最小油膜厚度和最大轴瓦单位载荷方面进行流 体润滑分析。 本文在经过对 GN16 发动机曲轴两次设计修正及上述的结构分析后，对曲轴 沉割槽圆角滚压力调整，并对滚压深度进行测量分析，最后运用 400H 交变负荷 耐久试验进行可行性的通过验证。 报告最后给出了 GN16 发动机曲轴材料更改并量产后在采购成本降低、曲轴 重量减轻、曲轴加工工艺性改进等方面的数据总结。结合实际情况，对 TG15 曲 轴由非调质钢材料改为球墨铸铁时，提出了在结构分析、工艺验证及试验验证等 方面的改善意见。 关键词，曲轴、球墨铸铁、多体动力学、扭转振动、流体润滑工程硕士学位报告 III Abstract Based on GN16 engine crankshaft substituting nodular cast iron for non quenched and tempered steel as the research object, structure analysis, process analysis and test for crankshaft after changed to nodular cast iron are performed. According to the engine kinematics, dynamics, balance, the theory of fluid lubrication and the torsional vibration theory, the finite element model of crankshaft system for an inline 4-cylinder 4-stroke engine is established, and using nonlinear multi-body system dynamics software AVL/Excite, multi-body system dynamics mode of rankshaft system is established. On the basis of the fatigue analysis theory, system dynamics equation of forced vibration and Reyonds equation, the crankshaft system characteristics such as dynamic fatigue results analysis in the free mode, main bearing load, stress of dangerous speed, fatigue safety factor and its distribution, the minimum fatigue safety factor under the different fatigue limit of material, one-dimensional torsional vibration analysis in one order and two order torsional inherent frequency, hub synthesis of torsional vibration amplitude, single order torsional vibration amplitude, hub dissipated power, cyclic speed irregularity, and the hydrodynamic lubrication analysis of crankshaft system in the minimum oil film thickness and maximum bearing unit load of main bearing and connecting rod bearing, are respectively analyzed. After two times of GN16 engine crankshaft design modification, the above structure analysis, crankshaft fillet rolling pressure adjustment and the measurement and analysis of fillet rolling depth, finally 400H alternating load durability test is verified and passes. The paper finally gives the summary data for the substituted GN16 engine crankshaft material in the aspect of cost reduction, weight reduction, machinability improvement etc. Combined with the actual situation of TG15 crankshaft, which will be substituting nodular cast iron for non quenched and tempered steel, the improvement suggestions are given in the aspect of structure analysis, process analysis and test etc.. Keywords: crankshaft; nodular cast iron; multi-body system dynamics； torsional vibration; hydrodynamic lubricationGN16 发动机曲轴球铁替换锻钢的可行性研究 IV 目 录 学位报告原创性声明和学位报告版权使用授权书II 摘要 II Abstract III 第 1 章 绪论 1 1.1 曲轴材料由球墨铸铁替换锻钢的背景及意义 1 1.2 国内、外曲轴材料的研究情况1 1.2.1 曲轴材料的发展趋势 .................................................................................2 1.2.2 目前国内、外曲轴材料的选用 ..................................................................2 1.2.3 目前 XX 公司发动机曲轴所采用的主要材料 ...........................................3 1.3 本文设计和研究的内容 3 第 2 章 曲轴系动力学分析 4 2.1 曲柄连杆机构运动学分析 4 2.1.1 活塞运动分析 .............................................................................................4 2.1.2 连杆运动分析 .............................................................................................7 2.2 曲柄连杆机构动力学分析 8 2.2.1 曲柄连杆机构运动件质量当量换算 ..........................................................8 2.2.2 曲柄连杆机构的作用力分析 ....................................................................10 2.2.3 曲柄连杆机构力的传递和效果分析 ........................................................11 2.3 曲轴系惯性力系的平衡分析 13 2.3.1 平衡的基本概念 .......................................................................................13 2.3.2 旋转惯性力平衡分析 ...............................................................................15 2.3.3 往复惯性力平衡分析 ...............................................................................16 2.4 曲轴系扭振分析 16 2.4.1 曲轴系扭振概述 .......................................................................................16 2.4.2 曲轴系扭振的当量转换 ...........................................................................17 2.4.3 扭转振动的激励力矩 ...............................................................................19 2.4.4 扭转振动的阻尼 .......................................................................................20 2.5 本章小结 21 第 3 章 曲轴系数学模型仿真理论22 3.1 有限元分析理论 22 3.1.1 有限元分析 ...............................................................................................22 3.1.2 有限元接触分析理论 ...............................................................................26工程硕士学位报告 V 3.1.3 子结构法...................................................................................................28 3.1.4 Excite 软件介绍 .......................................................................................30 3.2 曲轴系多体动力学理论 30 3.2.1 曲轴系多体动力学模型 ...........................................................................31 3.2.2 疲劳分析理论 ...........................................................................................31 3.3 曲轴系扭振计算理论 32 3.4 流体润滑性能分析理论 34 3.4.1 流体润滑理论的发展 ...............................................................................35 3.4.2 流体润滑理论基本假设 ...........................................................................35 3.4.3 流体润滑方程 ...........................................................................................36 3.5 本章小结 38 第 4 章 GN16 球铁曲轴系仿真结果分析 39 4.1 GN16 球铁曲轴设计修正及模型建立 39 4.1.1 GN16 球铁曲轴设计修正 .........................................................................39 4.1.2 GN16 球铁曲轴有限元模型前处理 .........................................................41 4.2 GN16 球铁曲轴系动力学及疲劳结果分析 42 4.2.1 仿真分析基本输入参数 ...........................................................................42 4.2.2 曲轴系动力学计算结果分析 ....................................................................44 4.3 GN16 球铁曲轴系一维扭振分析 49 4.4 GN16 球铁曲轴系轴瓦润滑分析 52 4.4.1 主轴瓦润滑分析 .......................................................................................52 4.4.2 连杆轴瓦润滑分析 ...................................................................................53 4.5 本章小结 54 第 5 章 GN16 球铁曲轴工艺和试验验证分析55 5.1 GN16 球铁曲轴的工艺验证 55 5.1.1 曲轴沉割槽圆角滚压工艺简介 ................................................................55 5.1.2 曲轴疲劳强度强化结果分析 ....................................................................56 5.2 GN16 球铁曲轴的试验验证 57 5.2.1 400H 交变负荷耐久试验..........................................................................57 5.2.2 试验台架考核结果分析 ...........................................................................58 5.3 本章小结 59 总结与展望 60