摘  要：连杆多应用于汽车发动机上，连杆起到了传递力的作用。连杆的小头孔链接于活塞，大头孔则连接于曲轴。连杆的运动规律两头孔大不相同，大头孔与曲轴一起进行的运动其轨迹为圆周，小头孔则是与活塞一起进行摆动，其轨迹为直线。连杆在发动机作用时承受了复杂的变载荷，及其容易发生形变等现象，故连杆的设计需要考虑连杆的刚度强度等高要求。

本论文主要加工汽车发动机内连杆的设计和工艺以及连杆被加工时家具的设计，由于连杆的易形变等现象，对连杆秉持着高强度、高韧性等要求。所以在加工设计连杆时，需考虑各方面的因素，研究各道工序的先后、主要与次要，从粗加工到精加工，都是一次改进的机会。每进行下一步的工序，我们将减小连杆尺寸的精度与形位公差，以达到可使用的要求。

关键词: 连杆；加工工艺；夹具设计；加工余量；加工精度

ABSTRACT：The connecting rod is applied to the automobile engine, the connecting rod plays the role of the passing force. The small head of the connecting rod is connected to the piston, and the head hole is connected to the crankshaft. The motion of the connecting rod is very different from the two holes. The motion of the head hole and the crankshaft is in a circle, and the small head hole is swinging with the piston, and its trajectory is a straight line. When the connecting rod is subjected to complex variable load and its prone to deformation, the design of connecting rod needs to consider the rigidity strength of the connecting rod.

This thesis mainly design the processing technology of the automobile engine connecting rod, and the design of the connecting rod is machining fixture, as a result of the connecting rod transfigure change wait for a phenomenon, the connecting rod with high strength, high toughness, etc. Therefore, it is necessary to consider the factors of various aspects in the process of designing the connecting rod, and to study the successively, main and secondary aspects of each process, from rough machining to finishing, is an opportunity for improvement. For each next step, we will reduce the precision of the link size and the tolerance of the shape bit to meet the requirements of availability.

Keyword: Connecting rod；Processing technology;  Deformation；Design of clamping device; Machining margin；Precision

目  录

摘要1

Abstract2

第 1 章 绪论6

 1.1课题背景和意义6

 1.2相关领域中已经有的研究成果以及发展现状7

1.3设计中主要内容7

第 2 章 发动机连杆加工工艺8

    2.1 连杆的特点结构 8

    2.2 连杆的毛坯和材料 8

2.3 连杆主要技术的要求   9

    2.3.1 大、小头孔轴心线于轴心线上的平行度 9

     2.3.2 大、小头孔两端面 10

    2.3.3 螺栓孔 10

    2.3.4 大、小头孔中心距10

2.4 连杆机械加工工艺规程 10

     2.5对加工工艺规程的分析14

     2.5.1 工艺规程的设计 14

     2.5.2 选择定位基准 14

     2.5.3 夹紧连杆的合理方法15

     2.5.4 加工主要表面 15

     2.6 各工序的加工余量、计算工序尺寸及公差 15

     2.6.1 加工余量的确定 15

 2.6.2确定工序尺寸及其公差16

     2.7 工艺尺寸链的计算 17

 2.7.1 对连杆盖的卡瓦槽计算17

2.7.2 对连杆体的卡瓦槽的计算 18

2.7.3工时额定的计算20

2.7.4 连杆的检验  21 2.7.5检验连杆大头孔圆柱度  21  2.7.6效验连杆体、连干上盖于大头孔中心线的对称度21    2.7.7 连杆大小头孔平行度的检验    22  2.7.8对连杆小头的强度校核23  2.7.9连杆衬套温度上升引起的应力与过盈装配23 2.7.10采用连杆综合量仪进行检验 24 2.7.11采用连杆称重测量分选打标机进行测量 24 2.8 本章小结 25