Original Article Thermomecanical study of high speed rolling element bearing: A simplified approach D Niel 1,2,3 , C Changenet 1 , F Ville 2 and M Octrue 3 Abstract Rolling element bearing is an essential component in mechanical transmission because it reduces friction between two rotating parts. Two main approaches to evaluate power losses are proposed in literature: (i) global engineering models using few input data; (ii) local models which are more accurate but need much more information on rolling element bearing geometry. Based on thermal network approach, an intermediate model is developed in this study. This new model allows obtaining lumped information (temperature of rings) with a minimum of input data (external geometry only) and by using global power loss models. This intermediate model is developed for angular contact ball bearing under oil jet lubrication for high speed application. Thermal network results are compared with experimental findings. Keywords Rolling element bearing, power losses, heat transfer, thermal network, rolling element bearing internal geometry estimation Date received: 13 June 2017; accepted: 23 November 2017 Introduction Rolling Elements Bearings (REB) are widely used in mechanical transmission to reduce friction between two rotating parts. With the development of the elec- trical motor in mechanical industry, REBs operate at high rotational speed. For these applications, power loss dissipation through REB can be predominant in mechanical transmission. An accurate estimation of this power loss is crucial to develop adequate cooling system and also to detect REB failures. A lubricant is used to reduce friction between the solid contacts and to cool the REB. But an excess of lubricant leads to an augmentation of REB friction torque. And due to this lubricant, REB power losses and its thermomechani- cal behaviour are strongly coupled. It is commonly accepted that REB power losses can be classified in two contributions: (i) load- depended power losses and (ii) load independent power losses. As underlined by Harris, 1 this classifi- cation corresponds to various sources of friction. The principal sources are listed below: – Sliding between rolling elements and rings and between the cage and rolling elements – Sliding due to the deformation of contacting element – Viscous drag of the lubricant on the rolling elem- ent and the cage – Hydrodynamic power losses. Depending on the authors, the above-mentioned sources of dissipation can be taken into account, or not, in their studies. It can be noticed that power losses due to the sliding between rolling elements and rings are always taken into account to estimate the power losses dissipated in a REB, but that is not the case for the other sources. As an example, Houpert 2 refuses to consider drag power loss but takes into account the hydrodynamic power losses. In others studies, drag losses are considered but hydrodynamic power losses are not. 3,4 To finish, other authors take into account the drag and hydro- dynamic power loss. 5–7 Drag loss can be a significant source of dissipation for high speed application; in literature different 1 Universite ´ de Lyon, LabECAM, ECAM Lyon, INSA Lyon, France 2 Universite ´ de Lyon, LaMCoS, INSA-Lyon, CNRS UMR5259, France 3 CETIM, Senlis, France Corresponding author: Fabrice Ville, LaMCoS, Ba ˆtiment Sophie Germain Avenue Jean Capelle F69621 Villeurbanne Cedex, France. Email: fabrice.ville@insa-lyon.fr Proc IMechE Part J: J Engineering Tribology 0(0) 1–12 ! IMechE 2017 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav DOI: 10.1177/1350650117750806 journals.sagepub.com/home/pij