【作者】 谭伟明；

【Author】 Tan Weiming Tang Dongwei (Mechatronic Engineering Department,Foshan University,Foshan 528000, China)

【机构】 佛山科学技术学院机电工程系；

【摘要】 针对椭圆齿轮传动提出了一种非零变位的方法。在传动比函数保持不变的前提下,使传动中心距略微改变(给定一个相对变动量),则会产生变位的效果。变位后的齿轮节曲线仍然是一对共轭的椭圆,其离心率与变位前椭圆节曲线的离心率相同,而大小的相对变动量等于中心距的相对变动量。变位前后节曲线共轭点处的切线、法线的斜率不变,但二者位置发生变化,因此造成共轭点产生了切向分离和法向分离。切向分离现象是椭圆齿轮传动所特有的,其分离量应作为生成齿条的切向变位量。法向分离现象则类似于圆形齿轮变位时的中心距变动,成为生成齿条的法向变位量。经齿廓曲线图形仿真证实,这种非零变位能够有效地消除根切现象,增大齿厚从而提高轮齿的强度。更多还原

【Abstract】 A new non-zero profile-shifted-modification method is raised for the elliptical-gears transmission.Similar to that of the circular-gears,the modified transmission is imagined as having the transmission ratio function be taken as that of the standard elliptical-gears,and the center-distance of the standard elliptical-gears given a little deviation.The modified transmission pitch-curves are still a pair of conjugate ellipse,with same eccentricity value as that of the standard elliptical-gears,and same relative deviation of size as that of the center-distance.Slope values of tangent lines and normal lines at the conjugate points on shifted pitch-ellipse are the same as that on the un-shifted pitch-ellipse, but the position of those lines of the latter are changed,making the conjugate points be departed from the original one tangentially and normally.The tangential departure is characteristic of the elliptical-gears transmission,and its departure amount ought to be taken as the tangential shifted-modification amount of the generating rack.The normal departure is similar to the center-distance departure in circular-gears modification,and its departure amount becomes normal shifted-modification amount of the generating rack.Both of the tangential and normal shifted-modification amounts vary with positions of the modified pitch-curve,so the so-called varying-coefficient profile-shifted-modification method must be taken into account to machine the modified elliptical-gears or describe the teeth profile of those gears.With graphic simulation of the teeth profiles,it is verified that by using of this modification method properly,undercut in gears can be eliminated,teeth width can be widened to make the gears stronger,but the contact-ratio may be decreased a little.Teeth profiles of the modified elliptical-gears aren’t totally symmetrical about the center of the ellipse,but are of thinner teeth near the rotation center than those far away from the center.This method can be used for the strength design of elliptical-gears and the adjustment of center-distance of those gear pairs. A new method for the modification of common non-circular gears may be worked out with the same thinking way as in this paper.更多还原