大模数少齿数螺旋齿面的四轴加工与仿真

Four-axis Milling and Its Simulation of Helicoid Gear Surface with Large Module and a Few Teeth

针对大模数少齿数螺旋齿轮的加工特点 ,结合渐开线和摆线的性质 ,利用微分几何工具计算出该类曲面的法矢 ,作为选取球头铣刀半径的依据。由于铣刀每完成一个行程后 ,还要进行轮廓插补 ,采用一种新的渐开线轮廓插补方法 ,并将插补轨迹换算成球头铣刀的刀心轨迹。分析了插补误差产生原因并提出控制方法。以一转子齿轮为例 ,仿真其加工过程。结果表明 ,本加工方法具有高效、高精度特点。

As it is impossible to machine the helicoid gear surface with large module and a few teeth by gear generating, a four-axis milling was developed in this paper. First, the normal vector of the surface was calculated using the differential geometry based on the features of an involute and a cycloid as a reference of radius of the ball milling cutter. As the interpolation of involute is necessary after each haul cycle of the cutter, a new kind of interpolation method is adopted, in which the interpolation tracks are transformed into the cutter center tracks. The factors causing the tolerances were analyzed and the controlling means were presented. At last, a rotor gear in pump, as an example, was put forward to simulate the course of its machining, which verifies the validity and the high order accuracy of the method.