渐变导程锥形螺杆的数控加工原理与建模

The Machining Principle and Modeling of Conical Screw with Continuous Grading Lead

利用复杂曲面包络原理 ,推导得出螺杆齿面的法截面内齿形不可能为同一形状的结论。因此只能根据某一法截面齿形 ,近似设计成形刀具廓形 ,或采用无瞬心包络法加工 ;同时 ,对于螺杆型面上的每一条螺旋线 ,为了保证其导程 ,加工中必须采用五坐标机床 ,设备复杂。提出了数控逼近加工的原理 ,使此类螺杆的加工在三坐标机床上即可完成 ,并且给出了实现机构的方案。

The expression of the flute of conical screw with continuous grading lead was complex in theory. To obtain the special screw with high accuracy, the machining principle must be studied and the mathematical model should be built. Based on the envelope principle of complex surface,a conclusion was drawn that the shape in normal section of these screws could not be the same. The profile design of the cutters could only be approximate. The method with non-instant center machining could be used. To ensure the machining of each helical line on the surface of the teeth along axis,a machine tool with five axes must be adopted,which was complex. So a scheme of approximate machining using CNC system was put forward and only three axis machine tool was needed. The model for machining was built and the mechanism was given.