An Experimental Study on the Motion Transmission Error of Planetary Gear Sets
An experimental study on the overall loaded motion transmission error of planetary gear sets is presented in this study. A test rig is designed and procured for the purpose of measuring the input-to-output transmission error of planetary gear sets within a range of input torque. The test matrix includes three distinct phasing conditions (in phase, sequentially phased and counter-phased) of a four-planet gear set as well as two planet tooth profile modifications. Two different power flow conditions with a fixed planet carrier and a fixed ring gear are considered. The transmission error results indicate that the phasing condition of the gear set is the most critical factor resulting in varying levels and numbers of modulation sidebands around the gear mesh orders. Planetary gear sets having in-phase planet meshes exhibit dominant gear mesh harmonic orders with little sideband activity, while sequentially-phased and counter-phased gear sets show an increase in planetary sideband orders associated with the sun, ring and planet gears. In addition, the power flow condition with fixed carrier is shown to have higher root-mean-square amplitudes of transmission error than configuration with a fixed ring gear.