Damage Condition Possible Causes Countermeasures

Cracks in the raceway ring and rolling elements. Continued use under this condition leads to larger Cracks or Fractures.

Excessive interference
Excessive load, shock load
Progression of Flaking
Heat generation and Fretting caused by contact between mounting parts and raceway ring
Heat generation due to Creep
Poor taper angle of tapered shaft
Poor cylindricality of shaft
Interference with bearing chamfer due to a large shaft corner radius
  • Correct the interference
  • Check the load conditions
  • Improve the mounting method
  • Use an appropriate shaft shape

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Cracks 1

Cracks 1

Part : Outer ring of a double-row cylindrical roller bearing

Symptom : Thermal cracks occur on the outer ring side face

Cause : Abnormal heat generation due to contact sliding

Cracks 2

Cracks 2

Part : Roller of a tapered roller thrust bearing

Symptom : Thermal cracks occur at large end face of roller

Cause : Heat generation due to sliding with the inner ring rib under poor lubrication


Cracks 3

Cracks 3

Part : Outer ring of a double-row cylindrical roller bearing

Symptoms : Cracks propagated outward in the axial and circumferential directions from the Flaking origin on the raceway surface

Cause : Flaking from a flaw due to shock

Cracks 4

Cracks 4

Part : Outer ring of a double-row cylindrical roller bearing used for outer ring rolling (Outer ring rotation)

Symptom : Cracks on outside surface

Cause : Flat Wear and heat generation due to non-rotation of the outer ring


Cracks 5

Cracks 5

Part : Raceway surface of outer ring of damage "CRACKS 4"

Symptom : Outside surface crack propagating to the raceway

Cracks 6

Cracks 6

Part : Inner ring of a spherical roller bearing

Symptom : Axial Cracks on raceway surface

Cause : Large fitting stress due to temperature difference between shaft and inner ring


Cracks 7

Cracks 7

Part : Cross section of cracked inner ring of damage "CRACKS 6"

Symptom : Origin is directly beneath the raceway surface

Cracks 8

Cracks 8

Part : Roller of a spherical roller bearing

Symptom : Axial Cracks on rolling surface



Motion & Control