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Abstract(s)
A presente dissertação tem como objetivo o projeto de um banco de ensaios de rolamentos, a fim de avaliar as diferenças de atrito num veio em rotação com e sem carga, através do binário de perda, preenchendo assim a lacuna existente no mercado, que diz respeito à falta de oferta de uma máquina de ensaios que forneça os valores das perdas de potência. Dos vários fatores possíveis para a ocorrência de perdas de potência, destaca-se o atrito provocado pelo rolamento, escorregamento, chapinagem e arrasto. Todas estas ocorrências estão dependentes das condições de serviço, a carga aplicada, o tipo de lubrificação, as condições de alimentação de lubrificação na zona ativa do contacto entre as pistas e os corpos rolantes e por último a altura de imersão. Posto isto, é fundamental proceder a essa avaliação para várias medidas de rolamento, com diferentes velocidades, cargas e lubrificação. Para esse efeito serão montados quatro rolamentos em um veio, onde os dois das extremidades terão de ser fixos. Para esta finalidade será apresentada uma solução de rápida execução, onde os apoios terão diâmetros fixos. Será aplicada carga nos dois rolamentos do meio com um cilindro pneumático, criando flexão em quatro pontos mantendo as condições de carga para ambos os rolamentos e lubrificação, altura de imersão na zona de contacto das esferas e as pistas dos rolamentos. Com a variação de diversas condições, será medida a alteração do binário por uma célula que estará à entrada do cárter, pela comparação da medição do binário no vazio, em que será possível determinar a perda de potência. A recolha destes valores permitirá tornar os modelos de perda de potência em rolamentos mais eficazes. Todo o processo de desenvolvimento, incluindo os cálculos necessários, a seleção de acessórios, entre outros, serão mostradas no decorrer do relatório. Se na solução final forem cumpridos todos os objetivos propostos e sendo uma solução viável, será avançado para a sua implementação.
The present work aims the design and sizing of a radial bearing test rig in order to evaluate the friction differences in a rotating shaft with and without radial load, though the loss torque, thus filling a gap in the market, which does not offer a testing machine that provides power loss values. Among the several possible factors for the occurrence of power losses, the friction caused by rolling, slipping, plating and dragging is highlighter. All these occurrences are dependent on the service conditions, the applied load, the type of lubrication, lubrication feed conditions in the active contact zone between the raceways and the rolling elements and the immersion height. That said it is important to make this assessment for various bearing measurements, with different speeds, loads and lubrication. For this purpose, four bearings will be assembled on a shaft where the two ends will be fixed. For this purpose, will be presented, a quick-running solution where the housings will have fixed diameters. Load will be applied with a pneumatic cylinder load to the two middle bearings, creating four points bending, maintaining the load conditions for both bearing and lubrication, immersion height in the ball contact zone and the bearing raceways. With varying conditions will be measured the change in torque, measured by a cell that will be in the crankcase, by comparison with the measurement of torque on an unsolicited shaft and could determine the power loss. Collecting these values will make the models of power loss in bearing more effective. The entire development process, including necessary calculations, accessory selection, and more will be shown throughout the report. If the final solution meets all the proposed objectives and is a viable solution, it will be advanced to its implementation.
The present work aims the design and sizing of a radial bearing test rig in order to evaluate the friction differences in a rotating shaft with and without radial load, though the loss torque, thus filling a gap in the market, which does not offer a testing machine that provides power loss values. Among the several possible factors for the occurrence of power losses, the friction caused by rolling, slipping, plating and dragging is highlighter. All these occurrences are dependent on the service conditions, the applied load, the type of lubrication, lubrication feed conditions in the active contact zone between the raceways and the rolling elements and the immersion height. That said it is important to make this assessment for various bearing measurements, with different speeds, loads and lubrication. For this purpose, four bearings will be assembled on a shaft where the two ends will be fixed. For this purpose, will be presented, a quick-running solution where the housings will have fixed diameters. Load will be applied with a pneumatic cylinder load to the two middle bearings, creating four points bending, maintaining the load conditions for both bearing and lubrication, immersion height in the ball contact zone and the bearing raceways. With varying conditions will be measured the change in torque, measured by a cell that will be in the crankcase, by comparison with the measurement of torque on an unsolicited shaft and could determine the power loss. Collecting these values will make the models of power loss in bearing more effective. The entire development process, including necessary calculations, accessory selection, and more will be shown throughout the report. If the final solution meets all the proposed objectives and is a viable solution, it will be advanced to its implementation.
Description
Keywords
Banco de ensaios Rolamentos Lubrificação Coeficiente de atrito Perda de potência Test rig Rolling bearing Lubrication Friction coefficient Power loss