发动机缸体夹具设计

SHANDONG ＵＮＩＶＥＲＳＩＴＹＯＦＴＥＣＨＮＯＬＯＧＹ

毕业论文

WD615发动机缸体前后端面及右侧面加工夹

具设计

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2013年6月

摘要

作为发动机上最大的零件，发动机缸体把发动机的曲柄连杆机构和配气机构连接到一起，并把供油、润滑、冷却等机构连接成整体。平面加工和孔系加工是发动机缸体加工的主要工作，平面加工主要通过端面铣削来完成，而孔系加工主要通过镗削、珩磨、钻、铰和攻等工艺完成。平面主要包括前后端面、底面和顶面，孔系主要包括水套孔、活塞缸孔、曲轴孔、安装孔、油孔、连接孔和销孔等。汽车发动机的使用性能与发动机缸体的加工质量有着直接关系，所以必须保证平面和孔系加工的精度。该课题的目的即对WD615发动机缸体机加工进行工艺设计，选择合适的加工中心、刀具，设计准确耐用的专用夹具，达到缸体加工生产的高精度、高效率、高适应性和高利用率。

我此次设计的主要内容是：以曲轴孔、止推面及左侧面一点为定位基准，精铣发动机缸体前后面、右侧面及油泵安装面，钻铰燃油泵定位销孔。我做的主要工作是：选择合适的定位面，设计合理的夹具，选取合适的加工设备和刀具，保证定位准确、工序内容布置合理、节拍平衡、工时优化、各加工要素符合产品图要求。

根据发动机结构复杂、刚度小等特点，定位夹紧方案的选择对缸体的加工精度、加工方式以及加工过程都有很大的影响，因此设计合理的机床夹具以保证加工精度，特别是保证被加工工件的加工面与定位面之间的位置精度，是设计中首先要考虑的问题。

刀具、机床和工件是机械加工三要素，缺一不可。而制造刀具材料的优劣，将直接影响机械加工的质量、效率和成本，所以选用合理的刀具，可以最大限度地发挥机床的性能。

为适应产品更新换代速度越来越快的趋势，在加工过程中缩短工艺流程、增加加工中心的柔性显得越来越重要。专用机床和夹具尽管在加工效率和批量生产方面有很大的优势，但柔性不够，不利于加工过程的改进，因此，选用合适的加工中心，使其拥有高的主轴转速、进给速度、换刀速度和高质量的刀具，并增加其柔性，对于保证优化加工保证加工质量起到非常重要的作用。

关键词：发动机缸体，定位基准，夹具，刀具，加工中心

Abstract

As the largest engine parts of the engine crank，the engine cylinder link mechanism and gas distribution organizations together, and put the oil, lubricating, cooling etc connection into a whole. Plane and hole machining is an important task of the engine cylinder block processing, surface processing is mainly completed through face milling, the hole is processed mainly by boring and honing, drilling, reaming and tapping process. Plane mainly includes front and rear end face, floor and roof surface, hole bore system mainly includes the water jacket, piston cylinder, curved shaft hole, mounting holes, oil hole, the connecting hole and pin hole, etc. The use of the automobile engine performance and engine block machining quality has a direct relationship, so must ensure that the plane and hole machining precision. The purpose of the subject of WD615 engine block machining process design, through the formulation reasonable process flow, select the appropriate machining center, cutting tool, and special fixture design accurate and durable, to block processing and production of high precision, high efficiency, high adaptability and high efficiency.

The main elements of this design are: based on crankshaft thrust face and left side hole, for the locating datum, precision milling around the face and right side and pump mounting surface, drill hole hinge pin fuel pump. My main job is: choose a suitable location, reasonable design of fixture, the selection of the appropriate equipment and tools to ensure accurate positioning, process optimization, content layout reasonable, balanced cycle time, work by processing elements conformity to product requirements.

According to engine structure complex, and stiffness small, features, in fixture of design process in the select what of positioning clip tight programme on cylinder body of processing precision, and processing way and processing process are has is large of effect, therefore design reasonable of machine fixture to guarantee processing precision, especially guarantee is processing workpiece of processing surface and positioning surface and is processing surface mutual Zhijian of location precision, is design in the first to consider of problem.

Tooling, machine tool and the workpiece is the most important elements. Advantages and disadvantages of the manufacture of cutting tools, will directly affect