Ease-off拓扑修形准双曲面齿轮齿面数控修正

为了改善汽车驱动桥综合传动性能,提出基于ease-off拓扑修形准双曲面齿轮设计与加工方法.预置传动误差及抛物线修形参数设计小轮法向自由ease-off拓扑修形曲面,建立小轮拓扑修形齿面模型,可以准确获得任意自由ease-off修形齿面的解析表达式.结合齿面承载接触分析(loaded tooth contact analysis,LTCA)方法,优化承载传动误差幅值(amplitude of loaded transmission error,ALTE)为最小,确定最优ease-off曲面参数,并推导其相对小轮理论齿面的目标修形量.基于刀具和计算机数控(CNC)机床各运动轴参数误差敏感性的齿面修正模型,分析各参数扰动对齿面误差的影响,进而确定合理的参数边界,以目标修形量误差平方和最小为目标函数,通过最小二乘法确定最优ease-off拓扑修形齿面的加工参数.结果表明:CNC机床各轴主要引起齿厚和对角修正,增加刀刃修正可以实现ease-off拓扑修形齿面的高精度修正,为高性能齿面自由ease-off修形设计与加工提供理论参考.

Tooth CNC correction for hypoid gears with ease-off topological modification

An approach of ease-off topological modification tooth design and correction for hypoid gears was proposed to improve comprehensive meshing performances of the automobile drive axle. The ease-off modification was expressed by both predesigned transmission error function and tooth profile modification curves, and an analytical expression of tooth with free ease-off flank modification for the pinion was established. The ease-off modification parameters were determined by minimizing the amplitude of loaded transmission error(ALTE) based on loaded tooth contact analysis(LTCA), and the objective deviations of theoretical tooth from the ease-off tooth for pinion were developed. Based on error sensitivities of the polynomial coefficients of kinematic axis and cutter head of CNC face-milling machine, flank topographic correction were determined, and reasonable parameter boundaries were determined. The influences of disturbed coefficients on the flank errors were investigated. With minimum sum of squared errors from the objective deviations as the aim function, an optimization algorithm was introduced to solve equations of the corrections. Numerical examples show that the tooth thickness errors and diagonal distortion errors were mainly corrected by the kinematic axes. Besides, with added tool edge correction, a high precision correction of ease-off topological tooth was realized. The study provides theoretical basis for the design, analysis and manufacture of free modified tooth of high-performance hypoid gears.