螺杆钻具转子的旋风式等法曲率铣削技术

Whirlwind Type Equivalent Normal Curvature Milling Technique on PDM'S Rotors

基于5轴卧式回转工作台数控铣床，提出了旋风式等法曲率铣削技术，实质是实时调整旋风式铣刀回转面的曲率方向，使其与被加工曲面密切贴近，形成曲率的逼近包络，可极大地增加刀具在被加工曲面上的扫描面积。

The stator/rotor coupling in a positive displacement motor(PDM) is composed of two paired conjugate-helical cylindrical surfaces, which possess the same pitch and the same spiral direction. The machining quality of the stators and rotors is directly related to enenrgy-converted efficiency in PDM. The whirlwind type equivalent normal curvature milling technique is a new milling method presented in this paper, based on 5-axis horizontal rotary-table CNC milling machines. And the key of this new technique is to make on-line control of the orientation of whiriwind type nilling tool in order to generate a perfect fit to the surface being machined with equivalent normal curvature. So, this technique can maximize the material removal area on the machined surface and enhance the milling rate and improve the surface finish. Geometric properties of helical surfaces on PDM's rotors, foundamentals of whirlwind type equivelent normal curvature milling technique and its mathematical equations are analyzed also.