Spiral bevel gear transmission mainly transmits the motion and power between vertical shafts, which requires the existence of bevel gear transmission pair in the transmission components of straight shaft. Gleason company of the United States has developed spiral bevel gear and its machining machine tool for this purpose. This spiral bevel gear machining method is called oerlikom machining method. This method is continuous milling. The longitudinal tooth line of spiral bevel gear is an epicycloid. The teeth are different with different curvature of each point, including large end to equal height teeth. NC machining technology promotes the development of spiral bevel gear machining technology. After turning, milling, grinding and other machine tools have realized NC, the spiral bevel gear machining machine tools with complex motion have ushered in the era of NC transformation.
The theory of post surface machining in NC machine tools makes gear grinding point by point, which breaks the traditional thinking of grinding by generation method. C28 machine tool is developed in the application of spiral bevel gear processing technology by using NC machine tool technology. High hardness alloy is adopted, and high-speed dry cutting is applied to spiral bevel gear processing, which greatly improves the productivity. The spiral bevel gear adopts a full CNC gear milling machine, which can process both spiral teeth by intermittent tooth division method and long epicycloid teeth by continuous tooth division method. At present, there are significant improvements and developments in bevel gear design and gear cutting adjustment in China.