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Analysis of Mechanical Characteristics for Key Parts of Harmonic Drive

Author: BiZhongGuo
Tutor: LiFeng
School: Jilin University
Course: Mechanical Engineering
Keywords: Harmonic gear drive Flexible gear Finite element analysis Mechanical properties
CLC: TH132.43
Type: Master's thesis
Year: 2011
Downloads: 198
Quote: 1
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Abstract

As a new transmission technology,the development speed of harmonic gear drive is very fast in recent decades. Harmonic gear drive mainly relies on the elastic deformation to transmit motion and loads. With progress and development of the society, after several decades in harmonic gear drive appeared, not only scientific powers research it, also some industrial comparative developed countries put a lot of human and financial resources to develop this new transmission technology, scholars from different countries have done a lot of work for all the problems in the practical application of this new transmission technology. Because the complexity and universality of the problems of harmonic gear drive, so far, there still have many problems are not solved completely. Therefore, the study of harmonic gear drive is very important. In this paper, the mechanical properties of key parts of the harmonic drive is studied, meanwhile,some analysis are done to the motion characteristics of the flexible wheel. The main contents as follows:(1) The trends and research status of harmonic gear drive technology were introduced and analyzed comprehensively, there are some differences between existing products of domestic and international harmonic gear drive in performance, the requirements of harmonic gear drives in the actual work environment is very high, especially to the installation space, life, carrying capacity and other requirements,based on these issues,the problems of finite element analysis of the mechanical properties of the key components of harmonic gear drives were raised.(2) Introducing the harmonic gear drive principle, structure,characteristics, and harmonic gear drive deformation of the flexible wheel,according to the basic formula of the deformation of flexible wheel,the displacement of the flexible wheel were calculated when it forced by four forces, getting the deformation of the flexible wheel. Finally, building a harmonic gear drives solid model in three-dimensional modeling software of CATIA, laid the foundation for finite element analysis of the mechanical properties of key parts of the harmonic gear transmission.(3) The harmonic gear drive rely on the gear meshing between the flexible gear and rigid gear to transmit motion and loads, flexible gear in the wave generator in the case of that just meshing with rigid gear, the elastic deformation of the flexible shell drive with the movement of the flexible gear, and with the mesh of the flexible gear and rigid gear to achieve conjugate movement and the wrong tooth movement. Therefore, the distribution of gear meshing contact force reflected the meshing performance of the harmonic gear drive. So it is possible to get the analysis of contact force of the teeth by the analyzing the contact force of finite element.(4) The flexible wheel is the main components of the harmonic gear drives device, flexible wheel is a thin shell. In the actual work environment, under the action of alternating stress, flexible wheel shell is prone to elastic failure. The harmonic drive unit life depends on the strength of the shell flexible wheel, Therefore analysis the strength of flexible wheel shell of the harmonic gear drive has great significance. This paper analyzes the shell size and distribution stress of flexible wheel.(5) Making a finite element dynamic analysis to determine the structural vibration. Modal analysis of the model can determine the vibrate level of a vibration mode in a particular direction, namely can determine the model’s natural frequency, vibration mode. In order to avoid structural resonance or vibration under the specific frequency, modal analysis of the model is very effective, so that designers can get models with different natural frequencies in different shapes, modal analysis of the model of the flexible wheel and the rigid gear meshing can get the vibration response of simulate the real work, so other mechanical properties can be analyzed.The stress and strain of flexible wheel under the load becomes very complicated, especially wave generator input speed is generally higher, flexible wheel under the influence of the wave generator occurs continuity of the elastic deformation, endured the alternating stress for long time, the life of harmonic gear drive depends on the strength of the flexible wheel to a large extent. Fatigue fracture of the flexible wheel teeth and shell is the most important failure modes of harmonic gear drive, hence in the study of improving the life of harmonic gear wheel, the distribution of stress condition of stress is very important.

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CLC: > Industrial Technology > Machinery and Instrument Industry > Mechanical parts and gear > The transmission mechanism > Meshing > Harmonic Drive
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