Examinando por Autor "Quintero, Héctor F."

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    Ball bearing vibrations model : Development and experimental validation.
    (2015-05-22) Grajales, Jairo A.; López, Juan F.; Quintero, Héctor F.
    The experimental validation of a mathematical ball bearing model with localized outer race defects is presented in this paper. The bearing is considered as a mass – spring – damper system, considering each rolling element as a contact spring – damper pair, based on Hertz equations for contact deformation, moving along the races. In accordance with the obtained results, in this work a bearing model is validated with a purpose built test bench. To compare the vibration signals from the real system and the model, spectral and high frequency analysis is used, particularly techniques commonly used on commercially available vibration analysis equipment, such as envelope and Peak Value analysis. The studied model shows a frequency behavior similar to that of the experimental data and the envelope and Peak Value analysis clearly reveal the characteristic frequencies of the studied type of defects. Resumen En este trabajo se presenta la validación experimental de un modelo matemático de rodamiento de bolas, en el que se incluye fallas en la pista externa. En el modelado se considera el sistema como un conjunto masa - resorte - amortiguador, tomando los elementos rodantes como conjuntos amortiguador – resorte de contacto, basados en las ecuaciones de Hertz para la deformación en contacto, desplazándose sobre las pistas. Acorde con los resultados obtenidos, en este trabajo se valida un modelo de rodamiento mediante un banco de pruebas construido para tal fin. En la comparación de las señales de vibración del sistema real y del modelo se utiliza análisis espectral y el análisis de alta frecuencia que se emplea en equipos comerciales de análisis de vibraciones, tales como análisis de envolvente y Peak Value. Se muestra entonces que el modelo estudiado presenta un comportamiento en frecuencia similar al ensayo experimental y que los análisis de envolvente y de Peak Value revelan con claridad las frecuencias características del tipo de fallos estudiados.
  • Miniatura
    PublicaciónAcceso abierto
    Use of the VAP function in the design of cam-follower mechanisms
    (Universidad del Valle, 2016-07-08) Quintero, Héctor F.; Vanegas, Libardo V.
    (Eng) A new mathematical periodic function, called VAP function, is proposed for the design of cam-follower mechanisms. With the VAP function, a given variable increases and decreases almost linearly from its minimum and maximum values, respectively, while the function and its derivate are smooth. As a case study, the design of a disc cam with a translating roller follower is considered, using four displacement laws: one based on a 4-5-6-7 polynomial displacement function, one based on a harmonic function, and two based on the VAP function. A comparative dynamic and kinematic analysis is shown. It is concluded that the cam-follower mechanism designed with the VAP function has smaller input torques, as well as lower pressure angles, than the one designed with harmonic function and that the one with 4-5-6-7 polynomial function.