| dc.description.abstract | The objective of this work is to minimize the maximum bearing temperatures under severe operating conditions in speed increasing and reduction gearboxes, and to present experimental data to validate the theoretical assumptions. The test machine, the experimental results, and the comparison between theoretical thermoelastohydrodynamic results and experimental data are presented. The test bearings are located in two speed increasing and reduction gearboxes (back-to-hack test bed). The high speed shaft bearings are five shoe tilting-pad journal bearings. They are 160 mm in diameter and the bearing ratio (L/D) is equal to 1.0. The rotational speed varies from 2700 rpm (22 m/s) to 11,880 rpm (100 m/s). The applied load is up to 88 kN. Three types of bearings permit analyzing the influence of the bearing design and the pivot position on the pad. The low speed rotor bearings are offset-halves journal bearings. They are 230 mm in diameter and the bearing ratio is equal to 0.75. The rotational speed varies from 765 rpm (9.0 m/s) to 3366 rpm (40 m/s). The applied load is up to 100 kN. The influence of the load direction and of the oil feeding temperature is studied. For each test, bearings, temperatures (film/pad interface, oil, pad and housing), power losses and oil flow are measured. Shifting the pivot from the central position to at least the 55 percent position leads to a decrease of the maximum temperature. The bearing design and materials contribute to improve its performance, especially a decrease of maximum temperature and power loss. | en |
