工程软件技能训练
课程设计说明书
院系名称： 专业班级： 学生姓名： 指导教师： 职 称：
工程软件技能训练
课程设计任务书
学生姓名 指导教师姓名 题目名称 院系 职称 从事 专业 专业、班级 是否外聘 □是■否 曲柄连杆机构设计 设计内容： 学会利用AutoCAD、UG及ANSYS等工程应用软件对汽车零部件进行设计和分析，为将来的工程实际应用打下基础。 自选某品牌轿车发动机的曲轴活塞连杆组进行设计，要求对曲轴活塞连杆组进行设计和校核计算，利用UG软件完成三维设计及装配，利用ANSYS软件对曲轴、活塞及连杆进行静力学分析，并最终利用AutoCAD软件完成二维总装配图A1一张，曲轴、活塞及连杆的零件图A2三张。 设计完成后应提交的成果： 1、设计说明书1份，字数为3000字以上，主体包括绪论、零部件的结构设计及校核计算、UG三维设计及装配、ANSYS有限元分析。 2、二维总装配图1张，A1大小，零件图3张，A2大小；
目 录
第1章 绪论 ······················································································································· 1
1.1 选题的目的和意义 ································································································· 1 1.2 国内外的研究现状 ································································································· 1 1.3 设计研究的主要内容 ····························································································· 1
第2章 活塞组的设计 ····································································································· 2
2.1 活塞的设计 ············································································································· 2 2.2 活塞销的设计 ········································································································· 5 3.3 活塞销座 ················································································································· 5 3.4 活塞环设计 ············································································································· 5
第3章 连杆组的设计 ····································································································· 6
4.1 连杆的设计 ············································································································· 6 4.2 连杆螺栓的设计 ····································································································· 9
第4章 曲轴的设计 ······································································································· 10 第5章 曲柄连杆机构的创建 ··················································································· 100
5.1 活塞的创建 ··········································································································· 10 5.2 连杆的创建 ··········································································································· 11 5.3 曲轴的创建 ··········································································································· 12
第6章 曲柄连杆机构 ··································································································· 13 第7章 ANSYS分析 ····································································································· 14 结论 ······································································································································ 15 参考文献 ···························································································································· 15
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。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。
1.2 国内外的研究现状
多刚体动力学模拟是近十年发展起来的机械计算机模拟技术，提供了在设计过程中对设计方案进行分析和优化的有效手段，在机械设计领域获得越来越广泛的应用。它是利用计算机建造的模型对实际系统进行实验研究，将分析的方法用于模拟实验，充分利用已有的基本物理原理，采用与实际物理系统实验相似的研究方法，在计算机上运行仿真实验。目前多刚体动力学模拟软件主要有CAD、CATIA、ANSYS等。多刚体动力学模拟软件的最大优点在于分析过程中无需编写复杂仿真程序，在产品的设计分析时无需进行样机的生产和试验。
1.3 设计研究的主要内容
对内燃机运行过程中曲柄连杆机构受力分析进行深入研究，其主要的研究内容有： （1）对曲柄连杆机构进行运动学和动力学分析，分析曲柄连杆机构中各种力的作用情况，并根据这些力对曲柄连杆机构的主要零部件进行强度、刚度等方面的计算和校核，以便达到设计要求；
（2）分析曲柄连杆机构中主要零部件如活塞，曲轴，连杆等的工作条件和设计要求，进行合理选材，确定出主要的结构尺寸，并进行相应的尺寸检验校核，以符合零件实际加工的要求；
（3）应用CATIA软件对曲柄连杆机构的零件分别建立实体模型，并将其分别组装成活塞组件，连杆组件，然后定义相应的连接关系，最后装配成完整的机构，并进行运动仿真分析，检测其运动干涉，获取分析结果；
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第2章 活塞组的设计
2.1 活塞的设计
2.1.1 活塞头部的设计
1、压缩高度的确定
活塞压缩高度的选取将直接影响发动机的总高度，以及气缸套、机体的尺寸和质量。尽量降低活塞压缩高度是现代发动机活塞设计的一个重要原则，压缩高度H1是由火力岸高度h1、环带高度h2和上裙尺寸h3构成的，即H1=h1+h2+h3
为了降低压缩高度，保证强度的基础上尽量压缩环岸、环槽的高度及销孔的直径。
（1）第一环位置
根据活塞环的布置确定活塞压缩高度时，首先须定出第一环的位置，即所谓火力岸高度h1。为缩小H1，当然希望h1尽可能小，火力岸高度的选取原则是：在满足第一环槽热载荷要求的前提下，尽量取得小些。一般汽油机h1?(0.06~0.12)D，D为活塞直径，该发动机的活塞标准直径D?80.985mm，确定火力岸高度为：
h1?0.09D?0.09?80.985?7.289mm取h1=9
（2）环带高度
为减小活塞高度，活塞环槽轴向高度b应尽可能小，这样活塞环惯性力也小，会减轻对环槽侧面冲击，有助于提高环槽耐久性。但b太小，使制环工艺困难。在小型高速内燃机上，一般气环高b?1.5~2.5mm，油环高b?2~5mm。
该发动机采用三道活塞环，第一和第二环称之为压缩环（气环），第三环称之为油环。取b1?1.5mm，b2?1.75mm，b3?3mm。
环岸的高度c，应保证它在气压力造成的负荷下不会破坏。当然，第二环岸负荷要比第一环岸小得多，温度也低，只有在第一环岸已破坏的情况下，它才可能被破坏。因此，环岸高度一般第一环最大，其它较小。实际发动机的统计表明，
c1?(0.04~0.05)D，c2?(1~2)b1，汽油机接近下限。 则 c1?0.045D?3.64mm，
c2?1.5b1?1.5?2?3mm。
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