【作者】 孙凌燕；

【导师】 叶邦彦；

【作者基本信息】 华南理工大学 ， 机械制造及其自动化， 2010， 博士

【摘要】 在传统工艺中,杯形薄壁内齿轮采用切削制齿与焊接工艺相结合的方式进行生产。旋压成形技术的出现,有效地弥补了传统工艺复杂、产品质量稳定性差等不足,是齿轮加工领域内的一项技术创新。内齿轮旋压成形过程中,材料流动情况比较复杂,与传统的普通旋压和强力旋压存在着明显的差异。因此,研究杯形薄壁内齿轮的旋压成形机理及工艺方法,不仅对提高内齿轮生产效率和产品质量具有重大意义,而且对发展旋压技术也有着重要的意义。本文的研究工作围绕杯形薄壁内齿轮旋压变形机理、工艺参数间的制约关系、成形工艺以及工艺参数的优化展开。论文的研究工作获得了国家自然科学基金项目“杯形薄壁内啮合直齿圆柱齿轮旋压成形机理及应用研究”(50475097)、广东省自然科学基金面上重点项目“杯形薄壁内啮合齿轮旋压成形机理及应用研究”(04105943)及广东省科技计划项目“齿轮制造业以旋压代替切削的关键工艺与装备技术研究及应用”(2006B11901001)的资助。在对内齿轮旋压数值模拟建模特点和相关有限元基本理论进行分析的基础上,以MSC.MARC为分析平台,对建模过程中涉及的接触边界条件、摩擦模型、网格划分和收敛准则判断等关键技术进行了探讨;并针对内齿轮旋压数值模拟中存在的计算效率低下、网格畸变问题,提出了有效的解决方案,建立了一个能够兼顾计算精度和计算效率的内齿轮旋压三维弹塑性数值模拟模型;。在三维弹塑性数值模拟结果的基础上,对内齿轮旋压变形机理及成形参数对轮齿成形的影响进行了研究。着重研究了内齿轮成形过程中的应力应变分布、材料流动规律,对制件各部位成形精度以及可能出现的成形缺陷做了预测,并就轮齿几何参数、芯模型面和工艺参数对内齿轮成形过程中材料流动的影响进行了分析,为内齿轮旋压的工艺设计提供了理论依据。本文对模拟分析的结果进行了试验验证。分析了内齿轮旋件轮齿和齿槽处的成形状况;研究了内齿轮成形中旋轮型面和轮齿类型对内齿轮成形的影响规律;采用试验设计和方差分析相结合的方法就工艺参数对内齿轮旋压成形质量的影响进行了定性和定量的研究,获得了对内齿轮成形质量产生显著影响的因素(或交互因素)。数值模拟的分析结果与试验结果吻合良好,表明本文所建立的数值模拟模型及由此获得的相关结论是合理的。模拟和试验结果显示,内齿轮(齿根处)齿厚与齿高比的差异会导致成形过程中的材料流动发生变化,据此可按制件的齿厚与齿高比大小将旋压成形内齿轮分为渐开线内齿轮和直廓内齿轮两类。针对渐开线内齿轮单道次旋压成形中出现的脱模困难问题,提出了两道次成形的工艺方案;针对直廓内齿轮单道次旋压成形过程中存在的旋压力过大和工件外侧表面质量较差问题,提出错距旋压工艺方案。工艺试验表明,上述工艺优化方案是可行的。针对目前内齿轮旋压成形中存在的依靠试模和经验进行工艺参数选择的现状,提出引入优化设计技术来进行工艺参数的选择:对于工艺参数的单目标优化问题,可运用近似模型法建立了一个能反映内齿轮制件成形质量与工艺参数关系的数学模型,实现了渐开线内齿轮工艺参数的优化;对于工艺参数选择过程中出现的多目标优化问题,通过灰色关联度分析技术的运用将多目标问题转换为单目标问题,实现了直廓内齿轮错距旋压的工艺参数优化。采用优化后的工艺参数,成功研制出渐开线和直廓内齿轮样件,为本文成果的推广奠定了良好的基础。更多还原

【Abstract】 In traditional technology, cup-shaped thin-walled inner gear is produced by stamping two pieces of the part separately, and then welding together. Spinning technology changes this status and it overcomes demerits of traditional cutting process, such as complicated process, low precision and high cost. During inner gear spinning, the deformation behavior of metal is very complex due to the partial thickening (in the area of gear-tooth) and thinning (in the area of tooth-groove), which is greatly different from that of the conventional and power spinning technologies. So the research work on inner gear spinning is of significance not only for the manufacturing of inner gear, but also for the development of spinning technology.The research mainly focuses upon the deformation mechanism, relationship among forming parameters, and forming process optimization of inner gear spinning. This project was financially supported by National Natural Science Foundation of China“Forming mechanism and application research on cup-shaped thin-walled inner gear by spinning”(50475097), Provincial Natural Science Foundation of Guangdong“Forming mechanism and application research on cup-shaped thin-walled inner gear by spinning”(04105943), and Industrial Science and Technology Development Program Foundation of Guangdong“Research and application on key technology and equipment for spinning instead of cutting in gear manufacturing field”(2006B11901001).Based on the analysis on the difficulties in establishment of numerical simulation model for inner gear spinning and the basic theory of large deformation elasto-plastic finite element, MSC.MARC is chosen as the FEA software. And the key technologies, such as the definition of contact and friction, meshing problem, and convergence criterion have been discussed. To solve the problems of mesh distortion and low computing efficiency in analysis, an effective solution is put forward.Based on the 3D elasto-plastic simulation results, the researches of the deformation mechanism and the influence of geometric and processing parameters on gear tooth forming have been carried out. It mainly focus on the metal flow rule during inner gear spinning, and the forming accuracy of spun part and forming defects have also been predicted, which establish a sound foundation for the practical application of the inner gear spinning technology.Various experimental verifications have been conducted for the simulation analysis results. These processing experiments mainly focus on the forming characteristics of spun part, and the influence of geometric parameters of roller and gear tooth on inner gear spinning. In addition, the technologies of experiment design and variance analysis are employed to analyze the processing parameters of inner gear spinning and the significant (interaction) factors for inner gear spinning are selected from various parameters. The simulation results conform well to the experimental ones. It shows that the numerical simulation model for inner gear spinning and relevant analysis are reasonable.To solve the problems occurring in original forming process, optimized forming processes are put forward. Two-pass spinning is adopted to solve the demoulding problem in involute inner gear spinning and stagger spinning is employed to solve the problems of the overload and poor surface quality in straight profile inner gear spinning. And the feasibility of these optimized forming processes is verified by the processing experiment.Optimization technologies are introduced to processing parameters selection. For the single-objective optimization problem of involute inner gear, a mathematical model is established by surrogate models-based methods, which indicates the relationship between forming quality of inner gear and processing parameters. For the multi-objective optimization problem of straight profile inner gear, the optimizated reduction distribution is determined by the gray relational grade obtained from the gray relational analysis. Based on the optimized processing parameters obtained from optimization design, the inner gear spun workpieces are produced successfully. It establishes a sound foundation for the practical application of the inner gear spinning technology.更多还原