|
SYMPTOM
|
CAUSE
|
SOLUTION
|
|
Flaking |
|
A.
|
On
rolling elements |
1.
|
Excessive
loading |
1. |
Inspect machine design and bearing selection. |
|
2. |
Excessive preloading |
2. |
Careful
installation |
|
3. |
Overloading
due to expansion |
3. |
Analyze
machine design and bearing application |
| B. |
Localized
on raceway |
• |
Presence
of dirt, rust, or scratches |
•
|
Replacement,
and consider use of a better protected bearing |
| C. |
Circumferential
on raceway |
• |
Presence
of dirt, rust, or scratches |
• |
Replacement,
and consider use of a better protected bearing |
| D. |
Areas
facing each other on the raceway |
1. |
Misalignment
of shaft or bearing housings |
• |
Correct
misalignment and install replacement with care |
| 2. |
Improper
installation |
| 3. |
Wear |
| E. |
Off-center,
i.e., circumferential on one side |
•
|
Excessive
thrust load |
|
Correct
misalignment or improper installation; select more suitable
bearing |
| F. |
Diagonal
on the raceway |
1. |
Deflection
of shaft |
• |
Correct
misalignment or improper installation; select more suitable
bearing |
| 2. |
Misalignment
of inner and outer races |
| G. |
Areas
spaced at pitch intervals of the rolling elements |
1. |
Vibration
without rotation |
• |
Suppress
vibration; better protection of bearings |
|
2. |
Rust |
|
| Seizing |
| A. |
Cracking |
1. |
Overloading |
• |
Misapplication;
Preload properly; check method of lubrication and selection
of lubricant |
| |
2. |
Improper
lubrication, e.g., |
| |
3. |
Improper
lubricant |
| B. |
Visible
damage |
• |
Overloading |
• |
Select
more suitable bearing |
| Cracking |
| A. |
Cracking |
1. |
Flaking
due impact while in operation or during installation |
1. |
Careful
handling and installation |
| 2. |
Excessive
clearance |
2. |
Inspect
mounting and preloading |
| 3. |
Excessive
interference or out of roundness |
3.. |
Check
for proper fit and concentricity |
| B. |
Splitting |
• |
large
shaft radius at bearing mounting shoulder |
• |
Inspect
accuracy of shaft and bearing housing construction |
| Rust |
| A. |
Throughout
bearing |
1. |
Improper
storage |
• |
Consideration
of storage, maintenance and corrosion inhibition |
| 2 |
Left
unprotected |
| 3. |
Poor
cleaning |
| 4. |
Inadequate
rust inhibition |
| B. |
Localized |
1. |
Improper
packaging |
• |
Improved
storage and maintenance practices |
|
2. |
Sweating
hands |
|
| C. |
Corrosion
on mounting surfaces, i.e., inner ring bore or outer ring outside
diameter |
1. |
Loose
mounting |
• |
Reconsider
construction of shafts and bearing housings; reconsider moisture
protection |
| 2. |
Inadequate
protection |
| Wear |
| A. |
Rapid
wear of rolling elements or races |
1. |
Presence
of dirt in lubricant |
• |
Inspect
lubricants and lubrication |
|
2. |
Rusting |
|
| B. |
Retainer
wear |
• |
Improper
lubrication, e.g., lack of |
• |
Inspect
lubricants and lubrication |
| Electrical
erosion |
| • |
Crater-like
pitting (fluting) |
• |
Electrical
sparking |
• |
Ground
stray currents; insulate bearing |
| Roughening |
| A. |
Roughness |
Dirt
pressed between rolling elements and raceways |
• |
Improve
maintenance practices |
| B. |
Sparkling
surfaces |
|
|
• |
Improve
maintenance practices |
| C. |
Striking
during handling |
• |
Careless
handling |
• |
Improve
maintenance practices |
| D.
|
Damage
during installation |
• |
Careless
installation |
• |
Improve
maintenance practices |
| Smearing |
| • |
Scratched
surfaces of raceways or rolling elements |
1. |
Improper
lubrication |
• |
Inspect
lubricant and method of lubrication |
|
2. |
Skewing
of rolling elements |
|
|
3. |
Improper
lubricant |
|
| Creep |
| A. |
Wear
of race mounting surfaces |
1. |
Excessive
clearance in mounting |
• |
Inspect
seating and accuracy of construction of shaft and bearing housings;
reevaluate design |
| 2. |
Looseness
of bearing retainer |
| B. |
Slippage,
discoloration |
• |
Abrasion |
• |
Inspect
seating and accuracy of construction of shaft and bearing housings;
reevaluate design |
