Skidding and spinning investigation of dry-lubricated ball bearings under axial and radial loads.

What is it about?

Skidding and spinning are two of the most important friction behaviours of the ball in angular contact ball bearings, which means the ball slides and spins relative to the raceway, respectively. Different from oil- or grease- lubricated ball bearings, elastic deformation (also known as creepage) of the contact particle will contribute to tangential friction forces between the ball and raceways, which makes frictional behaviours of the ball much more complicated. Therefore, the Kalker simplicated rolling contact theory is introduced to the quasi-static model of dry-lubricated ball bearing to consider the influence of creepage effects. The proposed model considers six degree-of-freedoms (DOFs) of the ball, thus can more accurately represent frictional behaviours of the ball. Using the proposed model, effects of loads, friction coefficients and inner ring speeds on bearing skidding and spinning behaviours is studied.

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Photo by SpaceX on Unsplash

Photo by SpaceX on Unsplash

Why is it important?

Due to the extremely high working speed and load, coupled with poor lubrication of solid lubricants, the rolling bearings in liquid rocket turbopumps have a maximum service life of only a few tens of minutes. Skidding and spinning behaviours of the ball relative to the raceway are important reasons for the wear of these bearings. Therefore, in order to provide theoretical support for the design and fault diagnosis of solid lubricated ball bearings under extreme conditions, it is necessary to establish an analytical model that can consider these extreme conditions. By using these highly realistic analysis models, problems can be identified during the bearing design phase and significant time and economic costs can be saved.

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