Miniature & Small ball bearings -Some Bearing Damages and Protection
If the equipment assembled with ball bearings did not work right, or if the ball bearings themselves were damaged, root causes of the failure can be determined by looking at the condition of the bearings. Higher performance and longer life can be achieved by preventing the damage. Some common failure modes and preventive methods against them are described below.
Abnormal Conditions
| Failure modes | Major causes | Solutions | |
|---|---|---|---|
| Rotation issue | Unable to rotate or hard to rotate | Grease (amount, type) | reviewing grease, improving (increasing drive force) drive system (motor) |
| Contact of parts | reviewing process and design | ||
| Grease degradation (wear particles) | reviewing lubricants, increasing grease fill amount, reviewing grease type | ||
| Flaking (flaking caused by metal fatigue) | reviewing load and rotation conditions, selecting larger size bearing | ||
| Noise | Continuous sounds | Resonance of components | reviewing dimensions (thickness) and materials of components |
| Brinells on the raceways | reviewing handling and assembly of the bearings, Reviewing transportation process of the equipment (excessive load and shock loads) |
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| Contamination dents on the raceways | changing designs to sealed type, reviewing working environment |
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| Intermittent sounds | Insufficient preload | reviewing preload amount from load and rotation conditions | |
| Contamination dents | changing designs to sealed type, reviewing working environment |
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| Dents on balls | reviewing process and working environment (contamination, excessive load) | ||
| Large vibration | Large internal clearance | decreasing internal clearance | |
| Improper preload | reviewing preload amount from load and rotation conditions | ||
| Misalignment | reviewing process, dimensional tolerance, cleanliness of the components | ||
| Deformation of the raceways | reviewing precision (roundness) of shafts or housings, reviewing glue and glue process |
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| Temperature increase | Improper grease type and amount | reviewing grease | |
| Excessive load | reviewing load resistance capability and fits | ||
| Grease leak | Improper grease type and amount | reviewing grease | |
| Improper selection of shield and seal | reviewing seal and shield | ||
| Damage of plastics (Cracking) | Chemical attack | reviewing lubricants, reducing stress, changing the plastic material |
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| Excessive interference | reviewing fits | ||
| Weld line | reviewing molding conditions and gate positions | ||
Damages
| Damage conditions | Causes | Solutions |
|---|---|---|
Flaking(flaking by metal fatigue)
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| Excessive load | reviewing bearing size and load conditions | |
| Improper assembly | reviewing assembling precision, dimensions of shafts and housings | |
| Dysfunctional lubricants | reviewing lubricant type and amount | |
Dents(brinelling)
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| Excessive load applied during assembly | Careful handling | |
| Shock loads applied during handling | ||
Rough surface
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| Contamination | reviewing process and working environment | |
| Dysfunctional lubricants | reviewing lubricant type and amount | |
Creeping
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| Insufficient interference | reviewing the fit and interference | |
Electric corrosion
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| Melting caused by electricity conducted inside the ball bearings | setting up insulation and grounding wire | |
