Computer-aided Design And Manufacturing Of Non-circular Gears

Gear transmissions is the most common transmission form in the machinery transmission. Among them, the circle gear transmission has been widely used as a fixed-transmission ratio pair, but it can hardly meet the demand of some mechanisms (especially some automatic mechanism) that can actualize variable transmission ratio. Non-circular gears can realize the variable velocity-rate transmission between two axes, and they also have special transmission characteristic in kinematics and geometry, but because of its complex calculation in design and difficult manufacture , non-circular gears have not been used widely so far. The application of computer science and CNC technology in non-circular gears design and manufacture will surely solve this problem.This paper summarizes and discusses the basic theory of non-circular gears, it is the foundation of the mathematics molding of non-circular gears. Then develop the CAD/CAM system for pitch curves and tooth profile of non-circular gears by using MATLAB language . The modules of pitch curves design realize that when giving transmission ration function, giving pitch curves of the driving non-circular gear, or realizing a function fitted for a pair of non-circular gears, checkout the parameter, make automatic design of the pitch curves. In the modules of tooth profile design the ellipse gear is mainly studied. Program to design and draw the figure of the tooth profile. Realize the simulated motion through programming. Examples are given for the both modules, through test we can know this system carries out correctly and steadily. It will aid the design and manufacture of non-circular gears efficiently .Finally, analysis and compare the main manufacture methods, decide to machining non-circular gears using linear cutting, 3B instruction is used to make the machining code. Data processing is needed before machining. Compare the methods of interpolation and fitting. Choose the quadratic approximation to fitting the tooth profile data, that is for the linear cutting of non-circular gears.