ANALYSIS OF THE RELATION BETWEEN THE FLEXURAL STRESS AND THE GEOMETRICAL VARIATIONS IN SPUR GEARS USING MODIFIED LEWIS’ EQUATION AND NUMERICAL METHODS

• Autor(a) principal: Quadros, Pedro M. S.
• Data de Publicação: 2017
• Outros Autores: Betim, Victor T., Ferreira, Ana Paula C. S., Silva, Carlos H. da
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Revista Interdisciplinar de Pesquisa em Engenharia
• Texto Completo: https://periodicos.unb.br/index.php/ripe/article/view/21797
• topic: Stress concentration factor. Lewis’ equation. Finite elements. Geometrical parameters. Flexural stress.

One of the failure types in spur gears is the teeth fracture caused by flexural stress in the tooth root region. In this way, this work objective is to validate and apply a numerical model to perform the flexural stress calculations in spur gears and evaluate the influence of some parameters in the stresses. Several works use numerical models validated by the stresses in the contact region calculated using the Hertz theory for nonuniform contact. However, when the interest is in the flexural stresses, it is considered more appropriate a validation based on the calculation of these stresses using solids mechanics concepts. In this paper the validation is done comparing the flexural stresses values calculated analytically and numerically in the critical point, which is in the tooth root. It is presented a modified Lewis’ equation for the analytical calculation, which considers load in the HPSTC (Highest Point of Single Tooth Contact) and a stress concentration factor. Once a validated numerical model is gotten, the module, number of teeth, pressure angle, center distance and velocity ratio are varied. The flexural stresses of the gears are calculated for each geometrical variation aiming at to map the influence of each one of these parameters in reduction of the flexural stress. The results showed that the validation strategy adopted was effective. Furthermore, the gear module and the number of teeth are the parameters that most affect the flexural stress.