OPTIMIZATION OF RAVIGNEAUX PLANETARY GEAR SET

Abstract

The advancement of the automotive industry tended to replace classical gears with fixed axes, withplanetary gear set with movable axes. Planetary gear sets have many advantages over classical gears, but theirdesign is more complex. One of the planetary gear sets, which is highly applicable in the automotive industry,is the Ravigneaux planetary gear set. This planetary gear set consists of gears with external and internaltoothing, which for different cases of movement of gears provides different output speeds and torques. Theoptimization of the module and the gear width of the the Ravigneaux gear set in order to reduce its mass, andtaking into account the values of the safety coefficient, was carried out in this paper. Observed optimizationfactors are: three materials (37Cr4, Ck15 and 15CrNi6), three modules (1mm, 1.25 mm and 1.5 mm) and threegear widths (20 mm, 22 mm and 25 mm).These values satisfy the conditions of the planetary gear kinematics.By optimizing the Ravigneaux planetary gear set saving of the mass of around 28% was achieved.