Material defects and manufacturing errors The ultimate failure causes for a bearing are material defects and manufacturing errors. Rolling bearing failures due to manufacturing defects make up less than one percent of overall bearing failures around the world.
Overlubrication occurs when a rolling bearing is greased excessively or when too much oil is added to the housing. Excessive grease or oil quantity may cause internal friction between rolling parts, which generates excessive temperature that can create stress and deformity of the bearing [9].
The supplementary functions are: heat dissipation from the bearing, removal of solid wear particles and contaminants from the rolling contact surfaces, corrosion protection, increase of the sealing effect of the bearing seals [4]. Lubrication is crucial for bearing life.
Excessive grease or oil quantity may cause internal friction between rolling parts, which generates excessive temperature that can create stress and deformity of the bearing [9].