Bearing Service Life

Each bearing is designed to work in a particular environment for a specific application and in each instance a bearing will have a certain "life expectancy". This is depends largely on the nature of operation and the way a bearing functions but natural wear and tear is inevitable.
The bearing’s service life is a function of its capacity to withstand fatigue or in more practical terms, the number of bearing revolutions up until first signs of fatigue. When rolling bodies roll on the raceway, they create significant cyclic, compression and shear stress loading. Like potholes in roads caused by the constant passage of cars and vehicles, bearing rings crack under the repeated passage of the rolling bodies.
Under standard conditions, the bearing will eventually be damaged. Contacts between rolling bodies and rings give rise to extremely high loads, both compression stress loading at the surface and shearing stress loading in sub-layers. The bearing's service life corresponds to its ability to withstand this stress loading
The bearing's service life can to some extent be predicted, it is a statistical data. In fact, it is mainly based on the probability of encountering conditions that will lead to fatigue. Other causes, usually abnormal, may cause premature damage of a bearing and impact bearing service life, notably:
  • Incorrect lubrication: too much or too little; wrong lubricant, etc...
  • Pollution: penetration of liquid or solid particles, hence the importance of seals as seal defects can give rise to leakage of lubricant and penetration of pollution.
  • Incorrect assembly; careless assembly, excessive heating, incorrect adjustment of gap clearance, excessive tightening of the taper sleeve, geometric defects, etc...
  • And various other reasons: use under unsuitable loads, incorrect adjustment, contact corrosion, passage of an electrical current, etc…
Thus bearings are designed and selected to have a specific service life under application operation conditions.