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

When debris such as small metallic particles are caught in the rolling contact zone, Denting occurs on the raceway surface or rolling element surface. Denting can occur at the rolling element pitch interval if there is a shock during the mounting (brinell dents).

Possible Causes Debris such as metallic particles are caught in the surface Excessive load Shock during transport or mounting Countermeasures Clean the housing Improve the sealing mechanism Filter the lubrication oil Improve the mounting and handling methods

Denting 1

Part: Inner ring of a double-row tapered roller bearing
Symptom: Frosted raceway surface
Cause: Debris caught in the surface

Denting 2

Part: Outer ring of a double-row tapered roller bearing
Symptom: Indentations on raceway surface
Cause: Debris caught in the surface

Denting 3

Part: Inner ring of a tapered roller bearing
Symptom: Small and large indentations occur over entire raceway surface
Cause: Debris caught in the surface

Denting 4

Part: Tapered rollers of damage “Denting 3“
Symptom: Small and large indentations occur over the rolling surface
Cause: Debris caught in the surface

Source: NSK