基于齿轮啮合原理和数控加工理论,提出一种余弦齿廓滚铣两步加工新方法,即首先利用标准渐开线滚刀滚切出渐开线变位齿轮作为粗加工,并使其加工余量最小;再在此基础上利用立式三轴数控铣床进行铣削成形精加工。建立余弦齿廓滚切加工最小变位系数的数学模型,推导出余弦齿廓铣齿运动的空间转换矩阵,得到三轴数控铣齿成形的通用运动控制模型,分别确定滚齿和铣削的加工刀具选择方法,避免加工过程中出现"过切"及"欠切"现象。最后通过具体实例进行Matlab和Pro/E加工仿真,验证理论模型的正确性和加工方法的可行性。
A two-step method to manufacture a cosine tooth profile is presented based on the gear meshing principle and computer numerical control(CNC) machining theory.The first step as a rough machining is to generate a modified-tooth gear by using a standard involute hobbing cutter in order to obtain a minimal machining allowance.Secondly,a spherical milling cutter is used to generate the cosine tooth profile on a three-axis CNC milling machine.The mathematical model of the minimum modification coefficient used in the first step is established.The space transformation matrix of milling the cosine gear profile is derived,and the kinematic control model of generation of three-aixs CNC milling machine is obtained.Selection methods of cutters for hobbing and milling are determined respectively in order to avoid the overcut and undercut phenomena.The simulation results of the machining process of a specific example obtained by the software Matlab and Pro/E demonstrates the kinematic control model is correct and the machining method is feasible.