The theory and method of ultrasonic lapping spiral bevel and hypoid gears are firstly purposed.The material removal mechanism of ultrasonic lapping gears specified as abrasives hammering to micro-cut

bouncing to impact and slurry cavitation is analyzed.The material removal model of ultrasonic lapping gears on the abrasives hammering to micro-cut is set up.The experimental comparison on the conventional lapping gears and the ultrasonic ones show that the material removal rate of ultrasonic lapping gears is three times of the conventional ones

and produces a better tooth surface quality

roughness Ra 0.2μm

section height c=1.2μm for bearing length ratio of profile Rmr（c）=100%.