Research And Analysis Of Transmission Error On RV Reducer In Robot

RV transmission is a new type of transmission developed on the basis of pin-cycloid planetary gearing. Compared to other traditional planetary transmissions,it has many advantages, and has been newly employed in industial Robot joints, which especially require high transmission precision.. In order to improve the precision and stability of the transmission, it is necessary to research and analyze the transmission error.This thesis aims at finding out the serere factors that influence the transmission error and giving rational guidance for design, manufacturing.In accordance with the structure of RV reducer and the principle of the transmission, the thesis first theoretically works out the bases for dynamic analysis, including:the expression of the transmission ratio of the reducer by using the structure kinomatic inversion method, determination of the source and factors which impact on the transmission error based on the error-causing theory and dynamic equivalent model of the reducer for analysis of transmission error with the condition of constant speed and ignoring the meshing friction of the gearing, at the same time, considering the manufacture assembly errors and elastic deformation of the components of the reducer as well. In the process of above equivalent transformation from the reducer to the model mentioned above, dynamic sub-structure method and lumped mass method are employed.The meshing stiffnes of the two-stage gearing in the equivalent model are calculated by Ishikawa, a revised through the use of Herz formula respectively. For the turning arm bearing and planet carrier support bearing the equivalent stiffness is caculated by using the bearing stiffness method. This paper takes RV-40E as the research object, the force, moment of inertia of the component and size are calculated through computer programming iteration.Solve the dynamic equation via computer simulating calculation with software MATLAB for RV-40E reducer under the condition of stable operating. Then the transmission error curve is obtained. In the calculation,31items of manufacture and assembly errors are respectively considered, which include the eccentric errors of sun gear, planet gear, crank shaft, holes on cycloid gear and on planetary frame, tooth profile error and accumulated tooth-pitch errors of cycloid gear and needle wheel, and so on. Furthermore, by comparing the transmission error curves of the reducer caused by each single above mentioned with each other, some severe factors which heavily impact on the transmission error are found. Consequently, further research has been taken by setting specific values of manufacture error in its tolerance zone to determine the corresponding transmission error curve respectively.