【作者】 杨建明；

【导师】 张策；

【作者基本信息】 天津大学 ， 机械设计及理论， 2001， 博士

【摘要】 三环传动是我国科技人员发明的新型的少齿差行星传动装置。该装置原理新颖,有许多独特的优点,如:传动比大,承载能力强,体积小,结构简单等。但振动、噪声较大,发热严重是其存在的突出问题,偏置型结构尤为严重。这些问题已经严重影响了其进一步推广应用。而所有这些问题都与动力学密切相关。另一方面,三环传动属于过约束机构,对这种过约束机构的动力学理论研究严重滞后。因此,从实践和理论两个方面都迫切需要对三环传动进行系统的弹性动力学研究。本论文正是基于这一迫切需要解决的问题而开展的。 和行星齿轮传动类似,三环传动有多于一个的内齿轮和同一个外齿轮啮合。其内、外齿轮齿数之间必须满足一定的条件,否则,会出现装配困难或根本不能装配。本文对这种安装条件,进行了详细的分析,并结合有代表性的三种机型,从便于管理和生产两个方面,对如何选择内、外齿轮齿数进行了探讨。三环传动属于过约束机构,要建立其动力学分析模型,必须计及系统的弹性变形。本文对这些弹性变形进行了系统的分析,建立了弹性变形之间的协调条件。 本文首次系统地建立了三环传动的弹性动力学方程。建立模型时,将整个传动系统分为输入轴子系统、支承轴子系统、内齿板子系统和输出轴子系统。分别建立各个子系统的振动方程,然后将各个子系统的振动方程组装成整体振动方程。在这个模型中,考虑了输入轴和支承轴的弹性弯曲变形、齿轮副的弹性变形、输入轴和支承轴行星轴承的弹性变形、偏心套的分度误差和偏心误差以及输出轴支承轴承的弹性变形。 分析了基于模态叠加法的封闭解法的实施过程,指出了其存在的问题,并推导了修正的方法。计算中对舍弃模态对系统动力学响应的影响引入了拟静态修正。 应用改进的封闭解法,首次对三环传动的动力学行为进行了系统的研究,分析了内齿板的加速度、啮合齿轮的准静态载荷和动态载荷以及各个轴承的准静态载荷和动载荷。结果表明,多相机构并列对平衡机构载荷十分有利,使得箱体支承轴承所受的载荷大大降低。而且三相机构并列后,不存在所谓的“死点冲击”。本文还首次计算出了三环传动的固有频率。 研究了误差对三环传动动力学响应的影响,结果表明,制造误差不仅影响三相机构间的载荷均衡,而且还会使三相机构的受力都有增加。 比较了不同构型的三环传动的动力学响应,结果表明,对称型三环传动的动力学表现远较偏置型优越。该结论说明,三环传动振动的主要原因是参数激励,而非多篇文献所认为的死点冲击。 研究了三环传动的设计参数对动态特性的影响趋势,这些参数包括:输入 轴行星轴承的刚度、支承轴行星轴承的刚度、齿轮综合啮合刚度、输出轴支承轴承刚度、内齿板的质量、输入轴与支承轴间的距离以及输入转速。更多还原

【Abstract】 Three-ring gear transmission is a novel type of planetary transmission with small tooth number difference, which was invented by a Chinese engineer. This new type of transmission has some distinguish advantages, such as large speed-reduction ratio, high load capability, compact volume and simple structure etc, over traditional gear transmissions and planetary trains. Some problems, however, still occur in run, among these problem are severe vibration, high level of noise and heat producing etc, all these problems are big obstacles in its further application and are closely related with the dynamics. On the other hand, three-ring gear transmission is an over-constrained mechanism. Theoretic study on dynamics of over-constrained mechanisms is less at present. So an extensive elastodynamic investigation is pressingly needed in both theory and application. This is just the purpose of this dissertation.Similar to planetary transmissions, two or more inner gears mesh with the same external gear simultaneously. So the tooth numbers of the gears must meet a certain condition, or it would be difficult or even impossible to assemble the transmission: In this dissertation, this condition was analyzed in detail and applied to three representative prototypes.Three-ring gear transmission is an over-constrained mechanism. So the elastic deformations must be taken into consideration in the dynamic model. This dissertation analyzed the elastic deformations and derived the coordinate relation between those deformations.The elastodynamic model of the transmission was established for the first time. In the modeling process, the overall transmission was divided into several subsystems. The dynamic model of the subsystems were built respectively and then assembled into the overall model. This model includes the elastic deformations of the main bearings and parts, and errors of cranks in both length and index.The closed algorithm was analyzed in detail and the faultiness of it was pointed out. A modification to the faultiness was derived afterwards. For compensating the effect of truncated modes on the response, a quasi-static compensation technique was incorporated into the model.A computer simulation was carried out with the modified closed algorithm. The simulating results show that the juxtaposition of two or more mechanisms can considerably reduce the load on the bearing of the housing. The natural frequencies of the transmission were given out for the first time also.The effect of manufacture errors of the cranks on the response was investigated. The result indicates that the errors not only affect the load-sharing but also increase the load on all gears.A comparison was made between the response of the two basic configurations under the same external excitation, and the result shows that the symmetrical is muchbetter than the unsymmetrical in dynamics. This further indicates that the primary factor causing the vibration is the parametric excitation instead of the impact at the dead points.The influence of design parameters on dynamic response was investigated, among these parameters are the stiffness of planetary bearings of input and support shafts, stiffness of bearings of output shaft, stiffness of the mesh gears, the mass of the inner gears, the distance between the input shaft and support shaft, and the driving speed.The parametric study reveals that the response is very high if the driving speed is close to 1/3,1/6,1/9 —of the first order natural frequency of the transmission. This phenomenon is called lower harmonic resonance. The reason for that is explained with perturbation method.In order to verify the theoretic analyses, experimental work was carried out. The experimental results confirmed the existence of lower harmonic resonance.更多还原