Dynamic Behaviour of Ball Bearing Applications with Constrained Damping Layers

Rolling bearing noise has become an aspect of increasing importance for the performance of rotating machinery, like electric motors and gearboxes. Generally, two aspects are important with regard to bearing noise, i.e. the transmission characteristics and the vibration generation characteristics. A potential source of vibrations are for example manufacturing imperfections of the di erent bearing components. Damping of bearing vibrations is enhanced by the lubrication lm between the rolling elements and the raceway of the bearing. Regarding vibrations of the total application, the reduction of vibration transmission can be increased by applying a constrained viscoelastic layer between the bearing and the housings. To design an e ective damping layer a 3D nonlinear time dependent computational model is developed to simulate the dynamic behaviour of a ball bearing application. The bearing model incorporates the sti ness and damping properties of the lubricant. Flexible components including the viscoelastic layer are modelled with FEM and reduced with a Component Mode Synthesis technique. Viscoelasticity is described both in the time and frequency domain by a generalized Maxwell model. The model is validated experimentally using constrained damping layer samples. Results are shown for a typical ball bearing application, showing that a proper design and material selection of the constrained layer is important for the reduction of the overall vibrations of the application.