The following Table 1 lists typical abnormal bearing sounds and their causes.Please note that the description of some of these sounds is rather subjective and thus could vary considerably from person to person.
Table 1: Typical Abnormal Bearing Sounds and Their Causes
| Sound | Features | Causes |
|---|---|---|
Hiss |
Small bearings |
Raceway, ball or roller surfaces are rough. |
| Buzz to Roar | Loudness and pitch change with speed. | Resonation Poor fit (Poor shaft shape) Bearing rings deformed. Vibration of raceways, balls, or rollers (For large bearings, if this sound is minor, then this is considered normal). Brinelling |
| Crunch | Felt when the bearing is rotated by hand. | Scoring of raceway surface (regular). Scoring of balls or rollers (irregular). Dust/Contamination Deformed bearing ring (partial interference clearance). |
| Hum | Disappears when power supply is switched off. | Electromagnetic sound of motor. |
| Chatter | Noticeable at low speeds. Continuous at high speeds. |
Bumping in cage pockets (insufficient lubricant)-- Eliminated by clearance reduction or pre-loading. Rollers bumping into each other on full-roller bearing. |
| Clang/Clatter | Metallic, loud bumping sound. Thin section large bearing (TTB) at low speeds. |
Bearing ring deformed. Grating of key. |
| Screech/Howl | Occurs mainly on cylindrical roller bearings. Sound changes with speed. Loud metallic sound that disappears temporarily when grease is added. |
Large radial clearance. Poor lubrication/grease consistancy. |
| Squeak | Metal-to-metal spalling sound. High pitch |
Spalling of roller and rib of roller bearing. Small clearance Poor lubrication |
| Squeal | Generated irregularly due to grating. | Slip on fitting surfaces. Grating on mounting seat, of key, etc. |
| Faint tinkle | Irregular (not changing with speed). Primarily on small bearings. |
Dust in bearing. |
| Rustle | Sound quality remains the same even if speed changes (Dirt). Sound quality changes with speed (Scoring). |
Dirt Raceway, ball, or roller surfaces are rough. |
| Rustle | Generated intermittently at regular intervals. | Chafing at the labyrinth. Contact of cage and seal. |
| Rustle patter | Regular and continuous at high speed. | Generated by retainer. Normal if sound is clear. Grease is inadequate if sound is generated at low temperatures (Use soft grease). Wear of cage pockets. Insufficient lubricant. Low bearing load. |
| Growl | Continuous at high speeds. | Scoring on raceway, balls, or rollers. |
| Quiet Fizzing/Popping | Generated irregularly on small bearings. | Bursting sound of bubbles in grease. |
| Large Sound Pressure | Large Sound Pressure | Rough raceway, roller, or ball surfaces. Raceway, rollers, or balls are deformed by wear. Large clearance due to wear. |
|Bearing Temperature|Operating Sound of Bearing|
| Vibration of Bearing|Lubricant Selection|Relubrication|
| Vibration of Bearing|Lubricant Selection|Relubrication|
