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Skidding behavior and unstable cage whirling of bearings are key factors limiting the service performance of a spindle-bearing system. This study proposes an improved dynamic model of ball bearings focusing on structure deformations and poor lubrication conditions. The ring deformations induced by the radial preload for the spindle-bearing-pedestal mechanical system are first discussed, and the asperity contact and starved lubrication conditions on the traction effect are further considered. Then, the cage flexibility induced by the centrifugal effect is determined by the lumped mass method, and cage clearance deformations are analyzed. On this basis, the dynamic equations are derived by investigating the motions and stress states among the bearing components, and the calculations are compared with experimental data to verify their accuracy and reliability. Finally, the regulatory mechanism of bearing skidding and cage motion stability from the perspective of bearing preload and structural parameters is revealed. The results show that although surface roughness and starved lubrication weaken the lubrication conditions of the ball-race, the traction effect is enhanced to reduce bearing skidding. Compared with the curvature radius of inner race, the groove diameter decreases the cage guiding effect, and ensures cage motion stability by suppressing the collision behavior of the ball-pocket. The system preload is more effective for improving the bearing service performance, which can optimize the collision force of the ball-pocket and increase the cage guiding effect. • A dynamic model of ball bearing with multi-factor coupling excitation is constructed. • Structure flexibility induced by spindle-bearing assembly state is considered. • The regulating mechanism of bearing skidding and cage motion stability is revealed. • Theoretical guidance for system preload and structure optimization is provided. [ABSTRACT FROM AUTHOR]

This manuscript presents a dynamic model of ball bearing considering cage flexible deformations and collision behavior of ball-cage pocket. The cage is firstly divided into a series of discrete mass units connected through springs, and the change in cage clearance is then considered to represent cage flexibility. The collision behavior of ball-pocket, the elastic connection force among cage discrete units, and the hydrodynamic action of cage-guiding ring are all analyzed to derive the dynamic equations for bearing components. The cage dynamic properties and instable whirling mechanism are explored. Discussions present that cage motion stability can be effectively improved by adjusting cage flexible characteristics, and appropriate preload and clearance design further optimize bearing service performance. • A dynamic model of ball bearing focusing on cage flexibility and transient collision is developed. • The deformed cage clearance induced by cage flexibility is explored. • The cage dynamic properties for the rigid and flexible cage model are comparatively analyzed. • Influencing mechanism of transient collision behavior and cage instable whirling motions is revealed. [ABSTRACT FROM AUTHOR]

• An improved dynamic model of ball bearing is proposed. • This model considers bearing deformations and ball-inner raceway separation. • A prediction method for the initial values is applied to solve dynamic model. • The influence of deformations and ball-inner raceway separation is discussed. In actual operation conditions, the bearing deformations caused by the change of assembly state play a major role in bearing dynamic performance, and the ball-inner raceway separation due to the insufficient preload or excessive external loads is also a key issue that limits the bearing service. In this paper, an improved nonlinear dynamic model of ball bearing considering bearing deformations and ball-inner raceway separation is proposed. Firstly, the relationships between the bearing deformations and bearing-shaft assembly state are directly derived according to the deformation compatibility condition, and the interaction and relative motions among various bearing components under the ball-inner raceway separation conditions are analyzed. Then a prediction method for the initial iterative values is used to calculate the dynamic model, and the calculation results are compared with the experimental data for verification. Finally, the variations of bearing deformations, contact properties, and cage skid under different factors are investigated. It is found that the bearing deformations affect the contact properties of ball-raceway, and the appropriate preload effectively improves the bearing service characteristics, especially under the ball-inner raceway separation conditions. [ABSTRACT FROM AUTHOR]

A comprehensive dynamic model of ball bearing focusing on structure flexible deformations is developed in this paper. The cage is split into several discrete segments linked by nonlinear springs to indicate the cage flexibility. The effect of cage flexibility on cage clearance is further considered. The race flexibility generated by assembly status variation of the shaft-bearing-housing system are then deduced, and the interplay mechanism between the race and other bearing components is analyzed. Finally, the effect of structure flexible deformations on bearing dynamic properties is investigated. The results indicate that rational design for structure flexibility can optimize bearing rotary performance. • A dynamic model of ball bearing considering flexible deformations is proposed. • The effect of cage flexibility on pocket and guiding clearance is investigated. • Raceway flexible deformations due to the change of assembly state are analyzed. • The mechanism of flexible deformations on bearing dynamic performance is discussed. [ABSTRACT FROM AUTHOR]