摆动输出活齿凸轮机构的凸轮廓面分析

传统摆动从动件凸轮机构具有体积小、价格低廉、运动特性良好、可产生复杂运动规律等优点，在印刷机械、农业机械、纺织机械、自动化办公设备等方面有着广泛的应用。随着自动化机械不断朝着高速化、精密化、轻量化的方向发展，对传统的摆动从动件凸轮机构提出了更高的要求。传统摆动从动件凸轮机构在实现大摆角范围输出时需要较大结构尺寸，且凸轮与从动件间多为单个高副接触，承载能力较弱，使其应用受到了一定程度的限制。本文以活齿传动和凸轮机构为基础，提出了一种综合两种传动形式优点的摆动输出活齿凸轮机构，具有齿数灵活、摆角范围宽、可按多种既定凸轮曲线规律摆动输出的特点。介绍了摆动输出活齿凸轮机构的结构组成及传动原理，通过引入凸轮曲线运动规律建立了输入-输出凸轮转角关系，推导了输入、输出凸轮的理论廓线方程和实际廓面方程。给出了凸轮理论廓线曲率公式，分析了凸轮理论廓线曲率最值的变化规律以及凸轮实际廓面不发生干涉的条件。由图形结果可以看出，输入、输出凸轮理论廓线曲率最值分别出现在齿顶及齿根处、始末端点处，其最大值曲线随比值e/R变化过程中存在增长拐点、顶点，并且干涉最先发生在理论廓线的最大偏置距的廓面截线上。因此，在凸轮实际廓面参数R、e、r取值过程中，应满足活齿半径r不超过限定值的条件，并尽量保证比值e/R小于曲线增长拐点所对应的比值且远离曲线顶点所对应的比值，以使凸轮廓面不发生干涉，机构能够平稳运转。

Cam Profile Surface Analysis of Swing Output Movable Teeth Cam Mechanism

Traditional cam mechanism with oscillating follower has the advantages of small size,low price,complex motion,and so on,which is widely used in printing machinery,agricultural machinery,textile machinery and automated office equipment,etc.As the automation machinery keeps moving towards high speed,high accuracy and lightweight,higher requirements are proposed for traditional cam mechanism with oscillating follower.When outputting a large angle,traditional cam mechanism with oscillating follower is required in great size structures.In addition,carrying capacity of traditional cam mechanism with oscillating follower is lower,because the contact between cam and follower is mostly high pair.So to some extent,applications of traditional cam mechanism with oscillating follower are limited.On the basie of movable teeth transmission and cam mechanism,a swing output movable teeth cam mechanism with advantages of both was proposed which has many superior attributes,such as flexible teeth number,full teeth mesh,wide range of swing angular and swing output regularly.The structure and transmission principle of the mechanism were introduced,besides,the angle relation of input and output cam were built by introducing cam curve and the equations of theoretical profile line and practical profile surface of input and output cam were deduced.The equations of curvature of cam theoretical profile line were given,and the change rules of the most values of theoretical profile line curvature and non-interference condition of cam practical profile surface were analyzed.From the graphical results,the most values of theoretical profile line curvature of input cam were on addendum and dedendum,and that of output cam appeared on start and end points,and the maximum curve with e/R ratio of cam theoretical profile line curvature had growth inflection point and peak,and the interference happened in the maximum offset profile surface cutting line of theoretical profile line.Therefore,when R,e and r parameters of cam practical profile surface are assigned,movable teeth radius r shouldn''t exceed the threshold,and trying to guarantee that e/R ratio is lesser than corresponding value of growth inflection point and far away from corresponding value of peak,and then,ensuring that cam profile surface has no interference and mechanism runs more calmly.