Dynamic Modeling of a Double-Row Cylindrical Roller Bearing with Three-Dimensional Defect

Purpose: The bearing defect in operating machines will expand in circumferential, axial and radial direction, but the defect change in axial direction is rarely considered in existing researches. 

Methods: A complete dynamic model of double-row cylindrical roller bearing with three-dimensional inner race defect is presented in this paper. Both the inner race and the outer race can move vertically and horizontally, and the inner race can also rotate around its axis. Each roller rotates around its axis and revolves around the bearing shaft. The radial load is applied on the outer race, and the interaction between the roller and the raceway is analysed in detail by formulating different coordinate systems to obtain the contact force and traction force, and then the corresponding moments are calculated. The lubrication state is considered as isothermal elastohydrodynamic lubrication, and the contact between the roller and the defect is simulated based on their spatial relationship. 

Results: Influences of the defect’s length, width and position on acceleration, contact force, roller slip characteristic and envelope spectrum are presented. In order to understand the coupling mechanism between local defect and distributed defect, dynamic behaviour of bearing with inner race defect and inner race misalignment is investigated. Results show that the fault characteristics of both defects can be observed concurrently. Experiments are performed and the results are in good accordance with the simulation ones 

Conclusion: The superiority of the three-dimensional fault modelling proposed in this paper is shown.