Synthesis and Evaluation in Epicyclic Transmission Design

A method for computer-aided conceptual design of automatic vehicle transmissions of epicyclic type is shown. Input to the method is required speed ratios and output is a set of transmission layout proposals. Presently, only epicyclic transmissions with one planet carrier are considered. The number of kinematically possible solutions is very large. The method sorts out solutions that are not physically feasible or too complex. This is done as early as possible, to avoid unnecessray work. The remaining layouts are evaluated with respect to some criteria, e.g. power losses, size and number of clutches and gearwheels.

Speed ratios from an existing transmission have been used as input to exemplify and test the method. The existing layout was among the layouts generated. Layouts simpler than the existing one were also generated.