An Approach to Determine and Analyze the Wear Rates at Cage Pocket Contacts in Solid-Lubricated Rolling Bearings

摘要

Solid-lubricated rolling bearings are widely known in many technical systems where conventional lubrication, such as oil or grease, fails due to critical conditions like vacuum or high temperatures. Polymeric cages (e.g., polyimide) endowed with molybdenum disulfide (MoS2) particles and silver (Ag) coating on the bearing components have proven themselves as dry lubricants that could significantly increase the service life of solid-lubricated rolling bearings. It has been demonstrated that during the bearing operation, material particles of the cage are transferred onto the raceways and lubricate the bearing. Thereby, the energy dissipates due to the momentary sliding at the ball-cage pocket interface. As a result of this behavior, the cage experiences wear apart from serving as a lubrication reservoir. In order to describe the lubrication transfer amount or the wear volume at the cage pocket, it is essential to estimate the material-specific wear rate. This contribution introduces an approach to determine and analyze the wear rates at the ball-cage pocket interface. In this article, only one example of lubrication coatings with specific operating conditions are shown, but the approach applies to other cases as well. This analysis has been achieved by performing bearing experiments under high vacuum conditions together with the combination of computational modeling. As an outcome, there are two aspects considered. The present contribution provides insight into the procedure to estimate material-specific wear rates. Additionally, it shows how wear rate data distribution can be analyzed. The future scope of this work is the input for the development of the model to predict and optimize the service life of such bearings to some extent.