【作者】 向俊；

【导师】 宋立权；

【作者基本信息】 重庆大学 ， 机械设计及理论， 2016， 硕士

【摘要】 飞轮总成是一种具有较大转动惯量的特殊圆盘,储备较高能量用于调节汽车速度波动,是发动机重要的外围构件之一。随着家用小汽车的普及,发动机飞轮的使用量急剧增加。因为飞轮总成的功能是发动机正常工作的必要条件,所以飞轮的安全性得到各界高度关注。针对飞轮总成的失效现象,本文按照失效分析流程系统地进行飞轮总成失效理论分析,得到了失效研究的两大主要方向:飞轮齿圈过盈配合失效和飞轮总成爆裂失效。利用弹性力学相关理论对飞轮齿圈应力进行计算,对相关参数进行数学分析。利用ansys workbench对飞轮总成和飞轮齿圈过盈配合进行有限元模拟分析,最后通过爆裂试验证明理论推导转速是飞轮总成的极限转速。本文主要研究工作分为如下几个部分:1根据弹性力极坐标平面问题建立平面基本方程,基于厚壁圆筒模型建立飞轮齿圈过盈配合力学分析模型,得到飞轮齿圈应力计算方法,推导飞轮齿圈在静态和动态下径向位移计算公式,根据变形关系得到两种状态下实际接触压强计算方法。根据飞轮齿圈理论推导公式得到理论解,采用有限元分析得到过盈配合模型的有限元解,通过对比分析两种结果,验证了过盈配合有限元分析方法是合理的,保证了后续分析的可行性。2飞轮结构复杂,建立合适的分析模型,利用有限元分析计算得到各组件的应力分布,根据分组分析结果得到了了过盈量、接触面半径、材料参数、飞轮本体空心度、轮缘厚度以及转速等参数对飞轮总成的影响规律,提出了针对过盈配合失效和总成爆裂失效的应对预防措施。选取三种产品进行动态有限元分析得到了总成的极限转速,样件根据不同过盈量分组,在不同转速下进行爆裂试验,试验结果符合有限元分析规律,验证了理论研究的正确性。飞轮齿圈总成有很多种失效形式,本文主要研究齿圈断裂脱落和飞轮整体破裂两种失效分析方法,从过盈配合失效和整体应力失效两个方面入手,得到了飞轮总成减小失效的措施。因此,本文的研究结果对工程设计有一定的指导意义,对工程的前期产品开发具有帮助,减少不必要的方案设计,节约开发成本,有利于企业发展。更多还原

【Abstract】 Flywheel assembly, a special disk with greater moment of inertia, reserving higher energy for adjusting the vehicle speed fluctuation, is an important member of the engine periphery. With the popularity of the family car, the amount of engine flywheel increase sharply. The normal working state of flywheel assembly is an important condition for the normal operation of the engine, so its security has been great concern all sectors.For flywheel assembly failure phenomenon, according to failure analysis process,this paper systematically theoretical analyzes flywheel assembly failure, and gets two main directions of researches in failure:the failure of the interference fit between flywheel and ring gear, as well as the flywheel assembly crack failure. Based on elastic mechanics theory, this paper calculates flywheel ring gear stress and mathematically analyzes the relevant parameters. Applying Ansys workbench, this paper has the finite element analyses of flywheel assembly and flywheel ring gear interference fit, and then the crack speed tests proves that the speed deduced from theory is the limited speed of flywheel assembly. The main work of this paper is divided into the following parts:1 According to plane situation under the elastic force of the polar coordinate,plane basic equation has been established. Based on thick-walled cylinder model, this paper build mechanical model of flywheel ring gear interference fit, and then gets the calculated method of flywheel ring gear stress to deduce the radial displacement formula of flywheel ring gear in both static and dynamic states. In the light of deformation relation, we can get actual contact pressure calculation within the two states. The contrast between theoretical solution, deduced from the theoretical formulation of flywheel ring gear, and finite element analysis solution of interference fit model proves the finite element analysis of interference fit is right, and ensures the feasibility of subsequent analyses.2 For the complex flywheel structure, it is essential to establish appropriate analytic model. By the finite element analysis, the stress analysis result calculated from each subgroup shows parameters, interference, the radius of contact surface, the material properties, the extent of hollow of flywheel, the thickness of flywheel rim,speed and so on, has an regular influence on flywheel assembly. As a result, this paper proposes preventive measure for interference fit failure and flywheel assembly crack failure. After the dynamic finite element analysis of three selected products, we get thelimited speed. Classified by varied interference, samples are experimented in different speeds. The results conform with the finite element analysis law, and verify the exactitude of theoretical study.With so many failure forms of flywheel assembly, this paper mainly studies two of them, the separation of flywheel ring gear and flywheel crack. Considering interference fit failure and overall stress failure, we come up with the measures that diminish failure of flywheel assembly. Thus, it is significant with this study results to guide engineering projects design, support primary product development, decrease unnecessary program design, save development costs, advance the enterprise development.更多还原