摘要:本文详细的介绍了四冲程发动机的连杆设计，连杆是发动机动力传递的桥梁，连杆材料的选取和形状的设计是整个发动机正常运行的最重要因素之一。

　　　本文先是从连杆组的运动学和动力学出发，分析了连杆组的角位移、角速度、角加速度、运动零件的质量换算以及受力分析，为后面对连杆组主要零件进行强度、刚度等方面的分析、计算和设计提供了依据。

　　　再根据连杆的受力情况设计连杆小头、杆身和大头的结构型式，根据发动机母机型号，为连杆组各零件选择材料，据此设计计算连杆组的主要结构参数，并对设计的连杆进行强度校核。

　　　然后分析了连杆螺栓的受力情况，选定螺栓的结构型式，设计计算螺栓的尺寸、装配预紧力并进行校核，提出提高螺栓疲劳强度的措施。

　　　再用UGS的Modeling模块对连杆组所有零件进行三维建模，包括连杆体、连杆盖、连杆轴瓦、衬套、螺栓、集油孔等，并用UGS的Assembly功能对各组件进行虚拟电子装配。

　　　根据计算结果对连杆大头部、连杆小头、杆身进行结构造型设计与改进，描述连杆的生产加工特点及加工方式，了解连杆的生产工艺，验证设计的合理性。

关键词：连杆，螺栓，UGS。

Abstract:This article describes the design of a four-stroke engine connecting rod in detail. The connecting rod is the bridge of power transmission inside the engine, the material selection of connecting rod and the design of its shape is one of the most important factors to the normal operation of the whole engine.

　　　According to this link group of kinematics and dynamics, it analyzes the angular displacement, velocity linkage groups, Angle acceleration, the quality of moving parts and stress analysis, providing the argument for the following analysis of the main parts , about strength , stiffness and so on.

　　　According to the force analysis of the connecting rod, the structural models of its small head, its body and big head are designed and materials of each parts are determined to match the model of master engine. Accordingly, the major structure parameters of connecting rod group are calculated and an intensive check is taken.

　　　And  then  the  force  of  the  connecting  rod  bolt  is  analyzed,  the  type,  size  and assembly pre-tightening force of bolts is determined and checked strictly at the same time, and the measures are proposed to improve the fatigue strength of bolts.

　　　By using the Modeling Module of UGS, the three-dimensional models of all parts of the  linkage  group  are  built,  such  as  the  connecting  rod  body,  connecting  rod  cap, connecting rod bearings, bushings, bolts, set hole and so on, then by using the Assembly Module of UGS, various components are virtually assembled.

　　　At last , according to the results, the structural designing of big head, small end, and body of the connecting rod is improved, then the production processing characteristics and processing methods of the connecting rod are described, the design rationality is verified.

Keyword:Connecting rod，Bolts，UGS