A new type of noncircular planetary differential is put forward for realizing the variable proportional distribution torque onto its two output axes

increasing the anti-skid function of differential and help to improve passing capacity for off-road vehicles.By analyzing transmission principle

the design method of pitch curves are given

and with involute tooth profile as a case

the parametric design program of non-circular gears is achieved to speed up planetary differential design with all sorts of parameter.Several kinds of new differential schemes are compared by structure

driving ratio and production process

which also shows the effectiveness of the new differential.