Lubrication of Rolling Bearings

This contribution covers the basics of lubrication of radial and axial rolling bearings. During the rotational operation of a bearing, the lubricant gets sheared between the surfaces in contact. The shear stresses are generating a hydraulic pressure that separates the surfaces and saves them from wear. This requires a certain viscosity of the lubricant. A common equation for the calculation of a required viscosity is introduced. This is a basis for a proper lubricant selection. Furthermore, the rheology of greases and their key characteristics for bearing lubrication are discussed. Afterwards the basics of bearing life calculation and the impact of the properties of the lubricants are presented. Furthermore, the typical applications of lubricants in rolling bearings in steel industry are discussed. Finally, an outlook on the latest trends of rolling bearing lubrication is given.