曲柄连杆机构设计说明书

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课 程 设 计 说 明 书

2115柴油机连杆设计

学生学号： 学生姓名： 专业班级：

指导教师姓名： 杜家益/张登攀

2018年 1 月

目 录

第1章 绪论 ·························································································· 1

1.1 选题的目的和意义 ········································································· 1 1.2 设计研究的主要内容 ······································································ 1

第2章 曲柄连杆机构受力分析 ······························································ 2

2.1 曲柄连杆机构的类型及方案选择 ······················································· 2 2.2 曲柄连杆机构运动学 ······································································ 3

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2 2.1.1 活塞位移 ············································································ 3 2.1.2 活塞的速度 ········································································· 4 2.1.3 活塞的加速度 ······································································ 5 2.2 曲柄连杆机构中的作用力 ································································ 5

2.2.1 气缸内工质的作用力 ····························································· 5 2.2.2 机构的惯性力 ······································································ 6 2.3 本章小结 ···················································································· 11

第3章 活塞组的设计 ··········································································· 11

3.1 活塞的设计 ················································································· 11

3.1.1 活塞的工作条件和设计要求 ··················································· 11 3.1.2 活塞的材料 ········································································ 12

第4章 连杆组的设计 ··········································································· 13

4.1 连杆的设计 ················································································· 13

4.1.1 连杆的工作情况、设计要求和材料选用 ···································· 13 4.1.2 连杆长度的确定 ·································································· 13 4.1.3 连杆小头的结构设计与强度、刚度计算 ···································· 13 4.1.4 连杆杆身的结构设计与强度计算 ············································· 15 4.1.5 连杆大头的结构设计与强度、刚度计算 ···································· 17 4.2 连杆螺栓的设计 ··········································································· 18

4.2.1 连杆螺栓的工作负荷与预紧力 ················································ 18 4.2.2 连杆螺栓的屈服强度校核和疲劳计算 ······································· 18 4.3 本章小结 ···················································································· 18

第5章 曲轴的设计 ·············································································· 19

5.1 曲轴的结构型式和材料的选择 ························································· 19

5.1.1 曲轴的工作条件和设计要求 ··················································· 19 5.1.2 曲轴的结构型式 ·································································· 19 5.1.3 曲轴的材料 ········································································ 19 5.2 曲轴的主要尺寸的确定和结构细节设计 ············································· 20

5.2.1 曲柄销的直径和长度 ···························································· 20 5.2.2 主轴颈的直径和长度 ···························································· 20 5.2.3 曲柄 ················································································· 21

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3 5.2.4 平衡重 ·············································································· 21 5.2.5 油孔的位置和尺寸 ······························································· 21 5.2.6 曲轴两端的结构 ·································································· 22 5.2.7 曲轴的止推 ········································································ 22 5.3 曲轴的疲劳强度校核 ····································································· 22

5.3.1 作用于单元曲拐上的力和力矩 ················································ 23 5.3.2 名义应力的计算 ·································································· 24 5.4 本章小结 ···················································································· 26

动力计算及图表 ···················································································· 28 结论 ····································································································· 41 致谢 ····································································································· 41 参考文献 ······························································································ 41

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第1章 绪 论

1.1 选题的目的和意义

曲柄连杆机构是发动机的传递运动和动力的机构，通过它把活塞的往复直线运动转变为曲轴的旋转运动而输出动力。因此，曲柄连杆机构是发动机中主要的受力部件，其工作可靠性就决定了发动机工作的可靠性。随着发动机强化指标的不断提高，机构的工作条件更加复杂。在多种周期性变化载荷的作用下，如何在设计过程中保证机构具有足够的疲劳强度和刚度及良好的动静态力学特性成为曲柄连杆机构设计的关键性问题[1]。

通过设计，确定发动机曲柄连杆机构的总体结构和零部件结构，包括必要的结构尺寸确定、运动学和动力学分析、材料的选取等，以满足实际生产的需要。

在传统的设计模式中，为了满足设计的需要须进行大量的数值计算，同时为了满足产品的使用性能，须进行强度、刚度、稳定性及可靠性等方面的设计和校核计算，同时要满足校核计算，还需要对曲柄连杆机构进行动力学分析。

为了真实全面地了解机构在实际运行工况下的力学特性，本文采用了多体动力学仿真技术，针对机构进行了实时的，高精度的动力学响应分析与计算，因此本研究所采用的高效、实时分析技术对提高分析精度，提高设计水平具有重要意义，而且可以更直观清晰地了解曲柄连杆机构在运行过程中的受力状态，便于进行精确计算，对进一步研究发动机的平衡与振动、发动机增压的改造等均有较为实用的应用价值。

1.2 设计研究的主要内容

发动机结构尺寸参数

发动机型号———————2115 活塞行程(mm)——————120 连杆长度(mm)——————185 缸径（mm）———————115 汽缸数—————————4 发动机转速(r/min)————2400 质量 活塞1240g

连杆大头1853g，小头705g

课程设计任务要求

1、 每小组绘制一种2115发动机连杆机构图纸。 2、 课程设计说明书一份。 具体要求如下：

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