Fundamental Theory And Experiments Study On Conic Cycloidal Planetary Transmission

Precision transmission is a kind of mechanical transmission mainly for high precision, which is extensively applied to many industry fields such as aviation and spaceflight, weaponry and equipment, NC machine tools, robot, precision machinery, printing and packaging machinery, transportation machinery, medical apparatus and so on. It is an important basic element in manufacturing equipment industry and national defense industry. The conic cycloidal gear planetary transmission is proposed as a new cycloidal gearing based on the theory that series of epicycloids are equidistant curves with radius of pins variable along its axis. The conic cycloid gearing can realize lower backlash by adjusting the axial location of the variable cross cycloid gear pair, and can gain higher transmission precision by error averaging with multi-tooth meshing. Therefore, it has important theoretical significance and reference value in the engineering practice to develop studies deeply and systematically on the related basic theory, machining and measuring, experiments of new conic cycloidal gearing.Major contents of the dissertation are as follows:①According to gear geometry kinematics, the meshing equation of parallel internal planetary drive is discussed, the general equation of conjugate surfaces of planet gear is derived, and the meshing theory of conic cycloidal gearing is developed. It is proved that series of epicycloids are equidistant curves with radius of pins variable along its axis. Design examples of linear variable cross section cycloid gear as conic cycloid gear and nonlinear as drum cycloid gear are given, and the numerical work is presented to demonstrate the correction of formulations. Profile equation of planetary gear whose cross section is a parabola is given, and diversity of profile surface of planetary gear is also discussed. Profile's curvature of variable cross section cycloidal gear and paraboloid planetary gear is discussed respectively.②The design method using the large end face of conic cycloidal gear as design standard is put forward, with which the profile surfaces of the conic cycloidal meshing pair are designed. Three innovative structural designs as N gearing, NN gearing and double-disc cycloidal gearing are developed based on conic cycloid gearing. And calculation examples for different structural designs are given respectively.③The force condition of the conic meshing pair is studied, and contact strength calculation method is proposed. Stress and strain analysis of the output mechanism concerning about cantilever beam type and simple supported beam type with separate pin sleeve and unique pin sleeve is carried out respectively with Finite Element Method.④The Windows-based visual analysis software system for the conic cycloidal gearing is developed with the Microsoft Visual C++6.0, which can realize automatic calculation on design parameters and profiles, and computer assistant design on mechanics of the N gearing, the NN gearing and double-disc cycloidal gearing.⑤New cutting/grinding method called"finger cone enveloping"is put forward, that is, the axis direction cone of the gear is shaped by finger conic cutter or grinder, and cycloid or arc profile is formed by enveloping. Machining simulations are respectively carried out. Three sets of prototype are developed by using this method.⑥The method of coordinate measurement and error evaluation on variable cross section cycloidal gear's profile surface is proposed. A general automatic measuring program of variable section cycloidal gear's profile surface is developed based on coordinate measurement machine. The precision measurement on profile surface of prototypes has been finished. Date processing method based on the least squares method is developed, and pitch error, profile error and conic error of conic cycloidal meshing pair are evaluated, which are important indexes to guarantee smooth motion and precision of conic cycloidal gear pair.⑦Experimental equipments are developed or refitted. Experimental study on three sets of prototype is carried out, which includes transmission efficiency, backlash and precision. The results show that three sets of prototype all have higher efficiency, double-disc cycloidal gearing can work well with larger axial loads, and can also adjusted the meshing clearance by adjusting the axial location of the meshing pair.