According to the characteristic of non-circle gear pitch line and method of calculation

all kind of non-circle gear pitch can be express by the uniform formula using subsection cubic spline

only the discrete points in the pitch of non-circle gear are needed. Using the curve fitted pitch

the universal calculation module of manufacture data of non-circle gear for all kind of non-circle gear can be got more easily. The process of calculation pitch length of an ellipse non-circle gear was given as an example to prove that this method is simple

accurate and practicable for computing CAM data of non-circle gear.