Nonlinear Dynamic Response of High-Speed Angular Contact Ball Bearings Considering Nonuniform Cage Thermal Deformation and Local Pocket Wear

Cage pocket wear and thermal deformation can jointly alter ball–cage contact conditions in high-speed bearings. However, their coupled effects on nonlinear bearing dynamics remain insufficiently studied. A nonlinear dynamic model is developed to account for nonuniform cage thermal deformation, frictional heat generation, wear-induced pocket clearance, and local stiffness variation. These effects are coupled through the ball–cage pocket contact relationship. System responses at different rotational speeds and wear depths are obtained by numerical integration. Nonlinear behavior is characterized using bifurcation diagrams, maximum Lyapunov exponents, phase trajectories, Poincaré sections, and frequency spectra. The results show that the cage temperature field and thermal deformation are nonuniformly distributed, with larger values near the cage pockets. Increasing cage pocket wear changes the bifurcation behavior and causes an earlier transition to chaos. When the wear depth increases from 0.5 to 1.5 mm, the onset speed decreases from 9600 to 8500 rpm. The spindle rotational frequency and cage rotational frequency are identified in both numerical and experimental spectra. Combination frequency components are also observed. For the upper sideband fs + fc, the difference between the experimental and numerical peak amplitudes is 5.31%. These results show that increasing cage pocket wear advances the transition to chaotic motion. The agreement between numerical and experimental characteristic frequencies also supports the proposed model under the investigated conditions.