In this paper, after analysing deformations of loading ball-bearing it is able to investigate vibrations of rotor-bearing system as the system with non-linear and periodically varying stiffness. | Vietnam Journal of Mechanics, VAST, Vol. 29, No. 3 (2007), pp. 397 - 413 Special Issue Dedicated to the Memory of Prof. Nguyen Van Dao ON THE TECHNICAL DIAGNOSTICS OF BALL-BEARING BASED ON MODELLING OF ROTOR-BEARING SYSTEMS BY VIBRATION METHOD NGUYEN CAO MENH Institute of Mechanics, VAST Abstract. In this paper, after analysing deformations of loading ball-bearing it is able to investigate vibrations of rotor-bearing system as the system with non-linear and periodically varying stiffness. The modelling of the systems is depent on properties of the shaft (rigid or flexible) and on measurement techniques for system vibrations (by eddy current proximity probe for rotating shaft or on non-rotating parts of the rotor-bearing systems) it can be described by a single degree-of-freedom or two-degree-of freedom nonlinear systems subjected to parameteric and external excitations. Therefore it is possible to obtain different characteristics of system vibrations with respect to different defects of ball-bearing. These symptoms help us to identify and estimate the bearing quality by measurement and analysis of system vibrations. 1. INTRODUCTION As we know, vibrations of machine is one of important signals for diagnostics of machinery condition. If the systems consist of rotating part (rotor) and supported-bearings, then it is called as rotor-bearing systems. The rolling element bearings are a type of bearings, its rolling element can be balls, rollers, tapered rollers, spherical rollers or needles. These bodies are positioned within a cage which holds them at a set spacing. In this paper the ball-bearing in a rotor-bearing system will be considered for some different types of rotors and the technical condition of the ball-bearings are estimated by processing and analysis of vibration data, which can be measured for the systems . Loading of the bearing leads to movement between the races. Their mathematical relationship must be known in order to be able to determine the .
