Several basic rack tooth profiles of hardened double-circular-arc gear in existence are introduced and discussed. A new kind of profile is developed

which is suitable for the carburized double-circular-arc gears with hardness of about 58HRC. These gears can be skived or grinded

and applied in low speed heavy duty transmission. Stress and strain of three kind of profiles was analysised by 3-D finite element analysis. The results show that the max stress of the new profile is 35% smaller than that of the GB/T12759 profile.