Eventos Anais de eventos
COBEM 2023
27th International Congress of Mechanical Engineering
Evaluation of Rolling Bearing Stiffness to Improve Critical Velocity Calculation
Submission Author:
Marcos Paulo Nostrani , SC
Co-Authors:
Rafael Möller, Victor Lazaro, Marcos Paulo Nostrani
Presenter: Marcos Paulo Nostrani
doi://10.26678/ABCM.COBEM2023.COB2023-1194
Abstract
Electric motors play a prominent role in modern industrial production. By converting electrical energy into mechanical energy, they enable the operation of most of equipment present in manufacturing processes. Despite the numerous standard lines available on the market, many customers have special applications, which must be analyzed in detail. One of the steps present in the customized design of these machines, is the calculation of the critical velocity of the rotor, which includes the shaft, the set of plates and the other components it supports. One of the parameters with great influence on the mathematical model used to predict the resonance frequencies of the rotor is the stiffness of the bearings, especially the radial one. However, there is still no consensus in the literature as to how to determine this value. Although the finite element method has gained great prominence in recent years, it is still very costly in terms of setup and computational effort. In order to increase the accuracy of this model, this paper evaluates a method to estimate the stiffness of rolling bearings from an analytical equation, which considers geometric aspects of the bearing and the load applied to it. The stiffness values obtained with this equation were compared with those provided by the main bearing manufacturers, which use different methods to calculate the stiffness, for a series of cases with different boundary conditions. Furthermore, experimental tests were conducted in order to validate the stiffness of bearings used in a case study. To carry out that, a run-up test was performed, correlating the machine vibration velocity with the rotor rotation frequency, which allows the estimation of its critical velocity. It is concluded, from the analyzed data, that the proposed equation underestimates the stiffness values of the analyzed bearings. In this case, the model used indicates a critical velocity value lower than that measured experimentally.
Keywords
Mechanical Vibration, Roto dynamics, Critical Velocity, Rolling bearing stiffness
