This paper proposes a simple approach on the synthesis of the 2D profiles for the rotors of cycloidal reducers. A 2D rotor (or cycloidal disc) profile (as a complex closed curve) can be defined (as an alternative to the strictly mathematical definition) as the internal bordered envelope of the family of 2D profiles of the stator (or ring gear) obtained with the stator movable (for at least a completely rotation) around the fixed rotor (or planetary gear) by respecting the gearing conditions inside a cycloidal reducer. The more 2D profiles of the stator are used the more accurate definition of 2D rotor profile is obtained. The finding of x, and y-coordinates of the points involved in the description of this 2D rotor profile is by far the most complicated problem to solve in the manufacturing of this type of reducer, the behavior and performances of the cycloidal reducer drastically depends by the accuracy of this profile. The results of this study can be easy applied in practice.

This paper intends to introduce a new approach in cycloidal reducers design. The usual design uses rotary pins as teeth on the ring gear (or stator as well) and an appropriate conjugate profile on the cycloidal disc (or rotor as well). This study proposes a new approach: to use rotary cylindrical pins as teeth on the rotor and an appropriate conjugate profile on the ring gear (or cycloidal ring) according with the rules of gearing. The main achievements of this paper focus on the synthesis of 2D internal profile of the cycloidal ring in transverse section. Some theoretical achievements and computer aided simulation results are briefly presented in this paper. This 2D profile is useful mainly for cycloidal reducer computer aided simulation and optimization but also for manufacturing purposes (by contour milling on CNC machines).