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Abstract(s)
Com o rĂĄpido desenvolvimento e o aumento de exigĂȘncia dos mercados, fatores como a eficiĂȘncia, fiabilidade e baixa manutenção sĂŁo cada vez mais importantes em mĂĄquinas cuja transmissĂŁo de binĂĄrio seja realizada por engrenagens. Todos este requisitos dependem de um processo que, atĂ© aos dias de hoje, ainda nĂŁo apresenta consenso na sua definição nem sobre que condiçÔes deve ser realizado: a rodagem. Esta dissertação reporta um conjunto elevado de ensaios experimentais de engrenagens, no qual se propĂ”em diferentes abordagens ao processo de rodagem, analisando o seu efeito na rugosidade superficial e na eficiĂȘncia da engrenagem. O principal objetivo deste trabalho Ă© o estudo da influĂȘncia de diferentes rodagens na eficiĂȘncia de engrenagens FZG do tipo C, quando lubrificadas por um Ăłleo de engrenagens PAO 150. Duas engrenagens foram submetidas a testes de rodagem, sendo que uma delas foi submetida a rodagem nos dois flancos, perfazendo entĂŁo trĂȘs ensaios. Antes de se iniciarem os testes experimentais, foi feita uma manutenção ao banco de ensaios FZG, onde foram substituĂdos os veios, rolamentos e vedantes de todo o banco. De uma forma sucinta, o estudo presente nesta dissertação assenta nos seguintes tĂłpicos fundamentais: âą Caraterização do Ăłleo de engrenagens PAO150; âą Execução de testes de rodagens; âą Execução de testes de eficiĂȘncia apĂłs as rodagens; âą Medição dos parĂąmetros de rugosidade antes e depois dos testes de rodagem e de eficiĂȘncia; âą Medição da massa das engrenagens antes e depois dos testes de rodagem e de eficiĂȘncia; âą Aplicação de um modelo de perda de potĂȘncia com o objetivo de verificar onde Ă© que as perdas sĂŁo mais significativas, e se os resultados obtidos experimentalmente se aproximam ou nĂŁo dos resultados numĂ©ricos. Como se irĂĄ demonstrar, as rodagens feitas nas engrenagens tĂȘm uma grande influĂȘncia no desgaste inicial de uma engrenagem, sendo que se verificou em todas as rodagens uma diminuição substancial da rugosidade das superfĂcies. Quanto aos testes de eficiĂȘncia, Ă© difĂcil afirmar qual das rodagens foi mais significativa, pelo que se encontram casos de eficiĂȘncias distintas nos 4 nĂveis de carga testados. Na aplicação do modelo de perda de potĂȘncia, foi possĂvel observar uma aproximação bastante satisfatĂłria entre os resultados experimentais e os resultados calculados analiticamente.
With the rapid development and increasing demands of the markets, factors such as efficiency, reliability and low maintenance are increasingly important in machines whose torque transmission is performed by gears. All of these requirements depend on a process that, until today, doesnât have a consensus on its definition or on what conditions should be performed: running-in. This dissertation reports a large set of experimental tests, in which different approaches are proposed to the running-in process, analyzing their effect on surface roughness and gear efficiency. The present work is aimed at the study of the influence of different running-in on the efficiency of FZG type C gears when lubricated with a gear oil PAO150. Two gears were submitted to running-in tests, one of which was subjected to running-in on both sides that it possesses, making a total of three running-in tests. Before starting the experimental tests, maintenance was performed on the FZG test rig where the shafts, bearings and seals of the entire test rig were replaced. The work reported here was based on the following topics: âą Characterization of gear oil PAO150; âą Execution of running-in tests; âą Execution of efficiency tests after the running-in tests; âą Measurement of roughness parameters before and after the running-in and efficiency tests; âą Mass measurement of the gears before and after the running-in and efficiency tests; âą Application of a power loss model with the purpose of verifying where the losses are most significant, and whether the results obtained experimentally are approximated or not the numerical results. As will be shown, the running-in tests made in the gears have a big influence on the initial wear of a gear, and a substantial decrease of the roughness of the surfaces was observed in all the tests. For the efficiency tests, it is difficult to say which of the running-in tests was more significant in terms of efficiency, because there are cases of different efficiencies in the 4 load stages tested. Regarding the power loss model, a very satisfying approximation between the experimental and the calculated results was achieved.
With the rapid development and increasing demands of the markets, factors such as efficiency, reliability and low maintenance are increasingly important in machines whose torque transmission is performed by gears. All of these requirements depend on a process that, until today, doesnât have a consensus on its definition or on what conditions should be performed: running-in. This dissertation reports a large set of experimental tests, in which different approaches are proposed to the running-in process, analyzing their effect on surface roughness and gear efficiency. The present work is aimed at the study of the influence of different running-in on the efficiency of FZG type C gears when lubricated with a gear oil PAO150. Two gears were submitted to running-in tests, one of which was subjected to running-in on both sides that it possesses, making a total of three running-in tests. Before starting the experimental tests, maintenance was performed on the FZG test rig where the shafts, bearings and seals of the entire test rig were replaced. The work reported here was based on the following topics: âą Characterization of gear oil PAO150; âą Execution of running-in tests; âą Execution of efficiency tests after the running-in tests; âą Measurement of roughness parameters before and after the running-in and efficiency tests; âą Mass measurement of the gears before and after the running-in and efficiency tests; âą Application of a power loss model with the purpose of verifying where the losses are most significant, and whether the results obtained experimentally are approximated or not the numerical results. As will be shown, the running-in tests made in the gears have a big influence on the initial wear of a gear, and a substantial decrease of the roughness of the surfaces was observed in all the tests. For the efficiency tests, it is difficult to say which of the running-in tests was more significant in terms of efficiency, because there are cases of different efficiencies in the 4 load stages tested. Regarding the power loss model, a very satisfying approximation between the experimental and the calculated results was achieved.
Description
Keywords
FZG test rig Running-in Roughness Efficiency Power loss model