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

Straight line scratches on surface of raceways or rolling elements caused during mounting or dismounting of bearing.

Possible Causes

Inclination of inner and outer rings during mounting or dismounting Shock load during mounting or dismounting

Countermeasures

Use appropriate jig and tools Avoid shock loads by using a press machine Center the relative mating parts during mounting

Mounting Flaws 1

Part: Inner ring of a cylindrical roller bearing
Symptom: Axial scratches on raceway surface
Cause: Inclination of inner and outer rings during mounting

Mounting Flaws 2

Part: Outer ring of a double-row cylindrical roller bearing
Symptom: Axial scratches at roller pitch intervals on raceway surface
Cause: Inclination of inner and outer rings during mounting

Mounting Flaws 3

Part: Rollers of a cylindrical roller bearing
Symptom: Axial scratches on rolling surface
Cause: Inclination of inner and outer rings during mounting

Source: NSK