International Journal of Analytical, Experimental and Finite Element Analysis (IJAEFEA), Issue. 2, Vol. 1, April 2014 © 2014 RAME IJAEFEA 1 Research Association of Masters of Engineering www.rame.org.in Aditya D. Khandare 1* adityakhandare@gmail.com Amit R. Bhende 2 amitbhendejobs@yahoo.co.in G. K. Awari 3 gkawari@rediffmail.com Dr. S.P. Untawale 4 untawale@gmail.com 1 M.Tech Research Scholar, 2 Asstt. Professor, Mechanical Engineering Department, SVPCET, Nagpur, India 3 Principal, TGPCET, Nagpur, India 4 Principal, DMIETR, Wardha, India Effect of Internal Radial Clearance on Performance of Bearing Abstract : The rolling bearings dynamic behavior analysis is a critical condition to determine the machine vibration response. The rolling bearing, with outer ring fixed, is a multi body mechanical system with rolling elements that transmit motion and load from the inner raceway to the outer raceway. The specific construction of a bearing has a decisive influence on its dynamic behavior. The paper defines a vibration model of a rigid rotor supported by rolling element bearings. By application of the defined model, the parametric analysis of the influence of internal radial clearance value and number of rolling elements influence on the rigid rotor vibrations in unloaded rolling element bearing was presented. Index Terms : analytical model, rolling bearing, ball passage frequency, internal radial clearance. I. INTRODUCTION Ball bearings are among the most important and frequently used components of the machines; however bearings may contain manufacturing errors or mounting defects. Such errors cause vibration, noise, and even failure of the whole system, which leads to expensive claims for damage. To avoid this and to ensure rapid and cheap production there is a need for a quick end-test of the machines to determine any bearing faults. The first step in bearing-fault detection during run-up would be a numerical model for the bearing-vibration response due to faults during the run-up. A well-defined vibration signal during the run-up of a faulty bearing could be used to find a suitable method for the fault diagnostic. A lot of research work has been done to model the vibration response of a bearing due to faults at a constant rotational speed. Tadina [ 1] presented an improved 2D bearing model for investigation of the vibrations of a ball-bearing during run- up. They presented numerical model assumes deformable outer race, which is modeled with finite elements, centrifugal load effects and radial clearance. Various surface defects due to local deformations are introduced into the developed model. The detailed geometry of the local defects is modeled as an impressed ellipsoid on the races and as a attended sphere for the rolling balls. The obtained equations of motion were solved numerically with a modified New mark time-integration method for the increasing rotational frequency of the shaft. The simulated vibration response of the bearing with different local faults was used to test the suitability of the continuous wavelet transformation for the bearing fault identification and classification. The experimental validation of the simulation was done by wavelet transformation. Upadhyay [2] presents a mathematical model to investigate the nonlinear dynamic behavior of a high speed rotor-bearing system due to defects of rolling elements. They used two defects for the study which are off size rolling element and waviness of rolling element. In the formulation, the contacts between rolling elements and inner/outer races are considered as nonlinear springs and also used nonlinear damping, which is developed by correlating the contact damping force with the equivalent contact stiffness and contact deformation rate. The equations of motion are formulated using Lagrange’s equation, considering the vibration characteristics of the individual components such as inner race, outer race, rolling elements and rotor. They solved the equation of motion using numerical line integration technique. Rubio [3] developed rolling bearing analytical formulation, the contact between rolling element and raceways is considered as nonlinear springs and their stiffness are obtained by using Hertzian elastic contact deformation theory. Equation of motion is developed using Lagrange’s formulation and simulation is validated using Algor© code and finite element method in time domain with dynamic events. Wensing [ 4] considered the stiffness and damping of the elastohydro dynamic lubricated (EHL) contact between ball and guiding rings. They formulated the equation using finite element modeling and time integration and component mode synthesis (CMS) is used as method of solution of equation. Experimental validation is done by vibration test spindles. Tillema [5] presented the 3D nonlinear time dependent computational model of rolling element bearing.