Quality control of hypoid gears using gear measuring machine

It is quite difficult to design, manufacture and measure hypoid gears, because it has a complex tooth flank form. Noise and vibration caused by inaccurate tooth flank form of hypoid gears is a big problem in automotive industry, and it becomes clear that a small deviation in tooth flank form can change gear noise considerably. High precision measurement of geometrical accuracy of tooth flank form of hypoid gears becomes recently possible not only by point-to-point measuring method but also by scanning tooth flanks. The measurement of hypoid gear tooth flank form and its data treatment are very difficult jobs because the gear tooth flank form is quite complex. The scanning measurement method which is first developed in the world to measure tooth flank form by using the virtual conjugate reference tooth surface, and the method of usage and treatment of its measured data for hypoid gears are introduced in detail. The scanning measurement has great information and enables quick, fully automated measurement of tooth profile and lead, therefore it is to suit controlling and management of tooth flank form quality for mass production of spiral bevel and hypoid gears. Some experiences and the effectiveness of the measurement of tooth flank form accuracy of hypoid gears are discussed.