星论文网欢迎您的来访,本中致力于各类论文代写,论文发表,代写代发论文服务

【中文摘要】 齿轮传动系统是机械传动系统的重要组成部分,随着齿轮传动系统应用领域的扩大,对齿轮系统提出更高要求。加强对齿轮系统动力学的研究,是提高传动系统性能的重要途径。深入研究齿轮系统动力参数,尤其是齿轮时变啮合刚度这一最重要的基本参数,对全面分析齿轮传动系统动力特点,提高机械传动系统性能有重要意义。本文以行星齿轮传动系统为研究对象,建立了行星齿轮系统微分动力方程,运用材料力学方法、有限元方法,及齿轮时变啮合刚度理论,针对石川轮齿变形公式,详细介绍了公式需要的重要参数——有效齿根圆半径及时变载荷作用距的具体计算方法,并提出改进的轮齿变形计算公式,并利用有限元方法进行了仿真对比验证,最后本文研究了齿轮动力系统刚度激励对齿轮系统应力状态的影响,并提出了减小齿轮刚度激励的方法。本文的主要研究内容如下:首先,根据齿轮系统动力学理论,建立行星齿轮传动系统集总物理模型,然后参照物理模型建立行星齿轮传动系统集总参数的微分动力学方程。并指出综合时变啮合刚度在动力学方程中的重要意义。其次,具体介绍了齿轮啮合轮齿变形的重要公式石川公式,提出了有效齿根圆半径及时变载荷作用距两个重要参数的详细计算方法。在此基础上,提出了...更多改进的齿轮啮合轮齿变形公式。简单研究了综合啮合刚度合成方法并利用算例对两公式进行了验算对比。然后,利用显式动力学有限元方法,针对行星齿轮传动系统进行计算机仿真,获得啮合齿面分度圆啮合位置某点在啮合周期内的变形曲线,并将此曲线与利用改进轮齿变形公式计算曲线进行了对比,从而证明了改进轮齿变形公式的合理性。根据应用需要,对此改进算法进行适当简化,提出一种新的齿轮时变啮合刚度简化函数法,并利用傅立叶级数分解法获得了简化综合时变啮合刚度公式的频谱表示公式。最后,在上述研究基础上,通过有限元谐响应分析法和工况组合法,分析了齿轮动力系统刚度激励对齿轮系统应力状态的影响,分析了刚度激励对齿轮疲劳强度的影响,证明通过选择合适的齿轮基本参数可以达到减小齿轮时变刚度激励,减小齿根应力集中,优化齿面应力分布,提高齿轮寿命的目的。 

【英文摘要】 The gear transmission system is an important part of the mechanical transmission. With the application field extending, more requirements are put forward to the gear system. Further research on the gear dynamics is the necessary way to improve the performance of the transmission system. If we want to get more characteristic of the gear dynamics in the globe aspect and improve the performance of the gear system, we must pay more attention on the parameter of the gear dynamics, especially the parameter of time-varying mesh stiffness is necessary.In this thesis, planetary gear system was studied. Differential equation of planetary gear system was established, according to theory of material mechanics, theory of finite element and theory of gear's time-varying meshing stiffness and the Ishikawa formula, more detail of the parameters were introduced which were refer to in the Ishikawa formula, e.g. effective root diameter, the distance of load. What's more, this paper proposed an improved f...ormula which was used to calculation displace of gear tooth when gears are meshing. And a comparison between the Ishikawa formula result and the improved formula result was show in this paper. CAE was used in order to get the value of displace of gear tooth when gears are meshing. The CAE result is also compared with the result of improved formula. At last, this paper studies on the effect of the stiffness excitation when the gears are meshing.Firstly, this paper set up the lumped parameter physical model of planetary gear according to the theory of the gear dynamics. Then differential equation of planetary was established in accord with physical model. And the significance of time-varying mesh stiffness was pointed out when it take place in the gear dynamics equation.Secondly, this paper introduced the Ishikawa formula concretely, and then this paper gives the solving steps of effective root diameter and the distance of load in detail. A improved formula was give by the paper, this improved formula make up the deficiency of Ishikawa formula. What's more, this paper also introduces the principle of composite stiffness, and the compare was taken between the result of Ishikawa formula and the result of improved formula by an example of the planetary gear system.Thirdly, the explicit dynamic analysis procedure was adopted. According to the planetary gear system which was mentioned above, we simulate the meshing process by the computer. And then we can get the displace curve of one node which was in the mating surface and near by the pitch circle. The node displace curve can be used to instead of the gear tooth displace curve. At last, this paper compares the FEA curve with the improved formula curve.Fourth, this paper introduces a new way which was used to simplify the time-varying mesh stiffness formula. The Fourier decomposition was be used to change the type of the simplify stiffness formula. In the new type of the stiffness formula, we can get the frequency of the sine wave easily, all the sine wave compose the stiffness excitation. this paper analyzes the effect of the stiffness excitation when the gears are meshing. In the process of analysis, this paper use the application of ANSYS and the technology of condition combination, the analysis type is harmonic. The aim of the result analysis focuses on fatigue of the gear tooth.At last, this paper also study on the effect of gear basic parameters on the time-varying gear mesh stiffness. Thought the numerical experiment, this paper have proofed that the stiffness excitation and the gear tooth root stress can be reduced by selecting the suitable gear basic parameters. 

【中文关键词】 行星传动系统; 石川公式; 有效齿根圆; 时变啮合刚度; 刚度激励
【英文关键词】 Planetary transmission system; Ishikawa formula; Effective root diameter; Time-varying mesh stiffness; Stiffness excitation