【作者】 郭艳丽；

【导师】 杨光；

【作者基本信息】 武汉理工大学 ， 机械制造及其自动化， 2009， 硕士

【摘要】 在曲轴加工工艺中,曲轴关键加工工序基准中心孔加工的是否精确合理直接影响曲轴后续其它工序的加工。如果曲轴中心孔加工不精确,那么后续曲轴的加工余量分布就不均匀,这将直接导致曲轴工件表面的加工质量较差,并增加曲轴的动不平衡量,从而导致报废量的增加。本文介绍目前常用的几种曲轴中心孔的加工方法,并对传统曲轴中心孔加工工艺进行了分析,针对曲轴定位基准的加工(打中心孔)做一些研究和探索。基于毛坯与成品最佳匹配的曲轴定位中心孔的加工工艺方法是将曲轴毛坯立体图形均匀包容曲轴设计模型立体图形,提高曲轴加工的质量。实现最佳匹配过程分成两步来完成:通过曲轴毛坯的粗匹配和粗匹配来实现曲轴毛坯的最佳匹配,对曲轴毛坯进行粗匹配使曲轴毛坯曲面与理论设计曲面在空间位置大致相近;对曲轴毛坯进行精匹配获得最佳的曲面匹配姿态和最佳的余量分布。曲轴毛坯的表面是由多个曲面组成,匹配难度和匹配计算量都比较大,为了降低曲轴毛坯匹配难度,减少匹配计算量,在对曲轴毛坯进行粗匹配的时候只选择具有代表性的局部特征进行粗匹配;而在接下来的精确匹配过程中,重点考虑曲轴毛坯的主要加工部位,也就是主要对曲轴的主轴颈和连杆颈进行精匹配。完成曲轴毛坯匹配的数学建模,采用遗传算法对数学模型进行求解,对曲轴毛坯进行判断识别,不满足加工要求的毛坯则提前报废,而对满足加工要求的毛坯,则对其进行自动寻位加工。自寻位加工就是通过机器视觉获取的曲轴毛坯重构图象与设计模型图象的最佳匹配获取的信息来控制动力头和工作台的位置运动,调整动力头及工作台的位置来适应加工孔的位置要求,最终加工出满足精确要求的曲轴中心孔。本文根据多轴加工机床的运动方案配置特点,确定曲轴自寻位加工机床的运动配置方式,并对机床动力头提出初步设计方案。更多还原

【Abstract】 In the crankshaft processing technology, the processing precision of the crankshaft main base central hole has a direct impart on the crankshaft follow-up machining. If the crankshaft central hole processing is imprecise, then the follow-up allowance distribution of the crankshaft is uneven, that will directly lead to poor quality of the crankshaft processing surface and increased dynamic unbalance of the crankshaft and the rejection rate of the crankshaft processing.This paper introduce recently the commonly used processing methods of crankshaft center hole, and analyze the traditional crankshaft center hole processing technology, do some research and exploration for the crucial working operation--base machining(drilling center hole) in crankshaft machining process, put forward a new crankshaft central hole processing methods which based on the optimum blank matching, the method is to make the three-dimensional graphics of blank crankshaft inclusive the three-dimensional graphics of design model, to make the processing allowance of rough crankshaft even, to improve the quality of the crankshaft machining.Divide into two steps to complete the best matching process ,through the rough and fine matching of blank crankshaft to achieve the best blank crankshaft matching, rough matching for blank crankshaft is to make the curved surface of blank crankshaft and the theoretical design curved surface broadly similar to the location in space. Fine matching is to get the best surface matching attitude and the optimum allowance distribution. Crankshaft blank surface is formed by a number of surfaces, so it is difficulty to match crankshaft blank, and the calculated amount of matching is too much. In order to reduce the difficulty and calculation of crankshaft blank matching, when carry out the rough matching of crankshaft blank ,only select the representative local characteristics to rough match; During the next process of fine matching, focus on the main processing site, that is the main journal and the crank arm for fine matching. In the crankshaft blank matching process to create a mathematical model, use the genetic algorithms to solve the mathematical model, judging on the identification for blank crankshaft, the parts which are not satisfied with the processing requirements are scrapped early, while for the parts which meet the processing requirements to automatic self-location machine.Self-location processing is use the information obtained through the optimum matching of crankshaft blank reconstruction model and the design model image, which obtained by the machine vision image, to control the location movement of power head and working table, adjusting the power head or the working table location to adapt to the request of center hole location processing, the final processing central hole of crankshaft to meet the precise requirement. This paper determine the movement configuration of crankshaft self-location machine tool according to the configure characteristics of the multi-axis machine tool movement, and Make preliminary design for the power tool.更多还原