Bearing Failure RCA: Smearing

 

When a rolling bearing is damaged during machine operation, the entire machine or equipment can seize or malfunction. Since bearings that fail prematurely or unexpectedly cause trouble, it is important to be able to identify and predict failure beforehand, so that preventive measures can be adopted.

Damage Condition

Smearing is surface damage which occurs from a collection of small seizures between bearing components caused by oil film rupture and/or sliding.
Surface roughening occurs along with melting.

Possible Causes

  • High speed and light load
  • Sudden acceleration/deceleration
  • Improper lubricant
  • Entry of water

Countermeasures

  • Improve the preload
  • Improve the bearing clearance
  • Use a lubricant with good oil film formation ability
  • Improve the sealing mechanism

 

Smearing 1

Part: Inner ring of a cylindrical roller bearing
Symptom: Smearing around circumference of raceway surface
Cause: Roller slippage due to excessive grease quantity

 

Smearing 2

Part: Outer ring of damage “Smearing 1”
Symptom: Smearing around circumference of raceway surface
Cause: Roller slippage due to excessive grease quantity

 

Smearing 3

Part: Inner ring of a spherical roller bearing
Symptom: Smearing around circumference of raceway surface
Cause: Poor lubrication

 

Smearing 4

Part: Outer ring of a spherical roller bearing
Symptom: Partial Smearing around circumference of raceway surface
Cause: Poor lubrication

 

Smearing 5

Part: Inner ring of a spherical roller bearing
Symptom: Partial Smearing around circumference of raceway surface
Cause: Poor lubrication

 

Smearing 6

Part: Outer ring of damage “Smearing 5”
Symptom: Partial Smearing around circumference of raceway surface
Cause: Poor lubrication

 

Smearing 7

Part: Convex rollers of damage “Smearing 5”
Symptom: Smearing of rolling surfaces
Cause: Poor lubrication

 

Source: NSK