【作者】 马志勇；

【导师】 郭铁桥；

【作者基本信息】 华北电力大学 ， 工业工程（专业学位）， 2016， 硕士

【摘要】 发动机缸盖是发动机的关键零件之一,是用来封闭气缸并构成燃烧室的箱体类零件。缸盖在内燃机属于配气机构,作为凸轮轴、摇臂轴和进排气管的支撑。首先在缸盖加工工艺改进方面,通过改工序分散为工序集中,单刀的多次加工为复合、组合多刃加工之后,减少了所用加工中心的数量,并且减小了多次重复定位带来的定位误差,充分发挥了加工中心的作用;其次,夹持缸盖的夹具采用一面两销定位方式,缸盖在空间的六个自由度完全定位,其中四个支承钉定位表面构成一个支撑面,限制缸盖的沿Z轴移动和绕X、Y轴转动三个自由度,圆销限制X、Y轴移动,菱销限制绕Z轴转动,保证缸盖定位精度;在夹具的自我找正、自定位装置方面,由液压油缸和导柱组成自动托料机构,在托料板放下工件的过程中,工件已经被托料机构的后定位挡块确定位置,结合定位销下端的锥度,实现缸体的自我找正、自定位;最后通过参考类似项目及专家多年来经验,得出该项目评价模型,运用AHP与模糊综合评价法对项目的实施情况进行定量与定性相结合评价。本文拟解决的问题是:从项目开始时的工艺流程设计到具体的夹具设计,再到该生产线交钥匙后,运用层次分析法和模糊综合评价法集成方法,对建立的项目评价模型进行综合评价,利用综合评价结果,可以使项目实施效果上有个量化的准则;通过准则层评价指标的综合评分,可以知道该项目在目标、进度和效益三个指标中哪个评分较高、表现较好,哪个指标有改进的空间,通过评价结果提出合理化建议,改进项目实施效果,提高交钥匙工程质量,以便对以后类似项目中的影响整个系统的重点因素进行控制,为以后类似项目的再次实施提供了参考。更多还原

【Abstract】 Engine cylinder head is one of the key parts of the engine, which is used to seal and constitutes the combustion chamber of the cylinder box-type parts. The cylinder head belongs to the gas distribution mechanism in internal combustion engine, it supports the camshaft, trocker shaft, intake pipe and outtake pipe. First, in the aspect of machining process improvement, through the process of dispersed to concentrated, by using common tool machining to compound multi- blade cutting tool, reducing the number of machining centers, and reducing the positioning error caused by multiple repeat positioning, and give full play to the role of processing center; Second, the fixture clamping cylinder head using a plane and two pits, six degrees of freedom in space is fully positioned, the location of four supporting nail surface forms a support surface, which limit cylinder head moving along the Z axis and rotating around the X, Y axis, round pin limits X, Y axis movement, edge cutting pin limits rotation around the Z axis, the above measures are in order to ensure the positioning accuracy of cylinder head. In the aspect of automatic orientation device for fixture, hydraulic cylinder and the guide column to form an automatic feeding mechanism, in the process of supporting plate falling in, the workpiece has been positioned in the rear position of the supporting mechanism, combined with the taper of end of the locating pin, the self- looking and self- locating of the cylinder block is realized; In the end, the project evaluation model is obtained by using the reference of similar projects and experts for many years. The combination of AHP and fuzzy comprehensive evaluation method is used to evaluate the implementation of the project.The problem to be solved in this paper is as follows: From the project process design to the specific fixture design, and then to the production line has been completely completed, using integrated method of analytic hierarchy process and fuzzy comprehensive evaluation to evaluate the project evaluation model. Through the comprehensive evaluation results, it can make the project implementation effect have a quantitative criteria. Through the second level evaluation index, we can know that which is better in the target, progress and effectiveness, what aspects to be improved. Through the evaluation results put forward reasonable suggestions, in order to improve the implementation of the project, improve the quality of the project, in order to control the impact of similar projects in the future and the key factors of the whole system.更多还原