Study And Development Of Digitally Designing And Manufacturing System For Globoidal Cam Mechanisms

The globoidal cam mechanisms compared with the conventional transmission mechanisms has high transmission speed,high indexing accuracy,and excellent dynamic performance.And its follower can complete various required movements.Currently,there are some kinds of digital design and manufacture software which can complete design and manufacture cam mechanisms with high effciency and high surface accuracy by computer auxiliary tools.However,at present,most of these softwares can only be applied to a single type of planar cam mechanisms or space cam mechanisms with a simple curved surface.Therefore,these software are limited a lot.In this thesis,various types of globoidal cam mechasnisms,including globoidal indexing cam mechanism,globoidal deceleration cam mechanism,swinging roller follower globoidal cam mechanism and ATC multi-head globoidal cam mechanism digital design and manufacture system is developed and designd based on the theoretical basis of Creo 3D modeling and MATLAB programming tool;the cam profile and non-equivalent five-axis machining tool data are realized conveniently by selecting the cam type,follower motion specifications of users.This thesis studies from the following aspects:(1)The principle of globoidal cam mechanisms is deeply studied,the general mathematical model of globoidal cam mechanisms is given,including contact equation,profile equation,pressure angle and curvature of globoidal cam mechanisms.The derivation calculations provides an important theoretical basis for research the three-dimensional modeling based on Creo and design the manufacture system of globoid cam mechanisms.(2)The research and manufacture method of globoidal cam are discussed;the machining method and characteristics of globoidal cam are summarized,especially the non-equivalent five-axis machining method is analyzed deeply;the control equations of non-equivalent machining tools for four types of globoidal cams are deduced.(3)The thin ridge problem of the large-angle-swinging multi-head globoidal cam in the parametric modeling is discussed in depth.Through analyzing the contour equation of globoidal cam and maximum pressure angle of globoidal cam machanisms,the thin-ridge position of globoidal cam appears at the position of maximum pressure angle is confirmed;A method for approximate estimate globoidal cam ridge thickness by using the knowledge of the distance between space curves in differential geometry is proposed to predicte whether the designed and processed globoidal cam can be satisfied.The specific value of the ridge thickness can also be obtained through the ridge thickness calculation interface of the globoidal cam mechanisms digital design manufacture system.(4)The basic principles and methods of designing the system by using MATLAB as a programming development tool is studied,and based on this,the cam design and manufacture platform is developed,the globoidal cam mechanisms including globoidal indexing cam mechanism,globoidal deceleration cam mechanism,swinging roller follower globoid cam and multi-headed globoidal cam for ATC contour and tool position machining data output and pressure angle,curvature confirmation,the ridge thickness calculation is realized.At the end,the principle,method and process of globoidal cam modeling are summarized based on Creo,and the solid model of globoidal cam is realized.