【作者】 孙小孟；

【导师】 周杰；

【作者基本信息】 重庆大学 ， 材料加工工程， 2006， 硕士

【摘要】 在汽车锻件中,曲轴是最重要的锻件之一。曲轴精密锻造技术是微车曲轴锻造成形工艺的重要发展趋势。对于精密锻造的微车曲轴,非调制钢将逐渐替代其它原材料。曲轴锻后只进行可控冷却,而不需要进行热处理,避免了热处理变形,节约了能源消耗。精锻后的曲轴只需少量加工就可直接使用,提高了生产效率及材料利用率,降低了生产成本,因此大大提高了曲轴的市场竞争能力。本文对曲轴的锻造成形工艺和国内外生产现状作了简要介绍,选择平面四拐微车曲轴作为典型件,详细介绍了在曲轴模锻工艺CAD与数值模拟CAE两个领域的工作。由于较复杂形状的曲轴类锻件锻造工艺复杂,其可行性、稳定性、成形质量(含充满成形、折叠、组织缺陷)、材料利用率以及如何降低载荷、提高模具使用寿命等,都是在制订曲轴成形工艺所必须重点考虑的。本文在三维造型软件Unigraphics(UG)的CAD平台下进行了133微车曲轴模锻的工艺分析与模具设计。针对曲轴成形过程的几个关键技术问题,利用有限元数值模拟软件DEFORM3D对其成形过程进行数值模拟。通过数值模拟,优化了预锻件的连皮厚度、模具结构和坯料尺寸,达到了优化工艺参数、优化模具结构、消除成形缺陷的目的。全面分析了曲轴锻造成形过程中金属的流动规律、应力应变分布、温度场分布和模具的温度场分布、应力场分布,随后通过一系列模拟,分析了摩擦系数对锻件填充情况、最大成形载荷、模具最高温度的影响,以及摩擦系数、压机速度、模具硬度对模具磨损量的影响,并通过多项式的最小二乘法拟合得到了它们之间的影响规律。最后,通过实验的方法,对工艺方案和模具设计的合理性与科学性进行了验证,对模拟结果与实验情况进行对比分析,总结了课题研究的成功经验。通过本课题的研究,将模锻工艺、有限元理论、数值模拟仿真技术及模具CAD技术结合起来,达到了缩短产品开发周期、提高模具寿命、降低成本等目的。本课题的研究成果对同类曲轴锻件的生产以及相关的模具设计提供理论和实践依据,并可直接用于指导生产。更多还原

【Abstract】 The crankshaft is one of the most important forge pieces of automobile. Precision forging technology of crankshaft is the most important development direction for tiny-automobile crankshaft forging technology. For precision forging crankshaft of tiny-automobile, non-quenched/tempered steel will replace other materials. After forging, the forged crankshaft only needs controlled-cold, not needs heat treatment, so it can avoid distortion during heat treatment and save a lot of energy sources. The precision of crankshaft can reach very high level, resulting in that the workpiece needs little machining to be used directly. The process improves producing efficiency and use ratio of materials, decreases producing cost. Therefore the competing ability of crankshaft is improved greatly.This paper briefly introduced the technology of crankshaft die forging and the development status of home and abroad , choosing 133 tiny- automobile crankshaft as the typical forge piece, particularly introduced the work in CAD and CAE of crankshaft die forging.The feasibility, stability,quality of forming (including brimming forming, replicate and organize disfigurement), material utilize efficiency and how to reduce load, how to improve mould life-span are all emphasized when we working out forming process of crankshaft because of its complicated forging process. By the use of the CAD system in UG, the forming process and die of 133 tiny-automobile crankshaft have been set up . In this paper, through adopting rigid-visco plastic finite element method (FEM) and using American advanced software DEFORM. Through FEM simulation, the web thickness of pro-forging pieces, the structure of die and the size of billet are optimized, attained the aim of optimize technology parameter, the structure of die and avoid defect. Analyzed the rule of metallic flow , the stress and strain, the temperature field of forged pieces , and also analyzed the temperature field and stress of the die. Later, through a series of simulations analyzed the relations between friction coefficient and metal filling, the maximal load, the maximal temperature of die. And also analyzed the relations between tool wear and friction coefficient, press velocity, hardness of the die. At the end, validated the rationality of the process and die of the 133 crankshaft through examination, contrasted the results between simulation and examination, summarized the succeed experience.更多还原