30 causes and solutions of bearing noise

The new bearing makes a noise after it is installed. I believe everyone must have encountered it. At this time, what we think of must be the return of goods, but is the bearing noise necessarily due to the quality of the product? Today I’ll share some ways to help you.

Sound of bearing in normal operation

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1. If the bearing is in good continuous rotation state, it will make a low whine or buzzing sound. If a sharp hiss, squeak and other irregular sounds are made, it often indicates that the bearing is in poor continuous rotation condition. Sharp squeaking noises may be caused by improper lubrication. Improper bearing clearance can also cause metal sound.
2. Dents in the track of the bearing outer ring will cause vibration and cause a smooth and crisp sound.
3. If there is intermittent noise, the rolling parts may be damaged. This sound occurs when the damaged surface is rolled out. If there are pollutants in the bearing, it will often cause a hissing sound. Serious bearing damage can produce irregular and loud noise.
4. If the knocking scar caused by installation will also produce noise, the noise will vary with the bearing speed.

Abnormal bearing noise

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Typical abnormal sound characteristics and causes of bearing.

Sound description Features Cause of occurrence
Whine
The sound quality does not change with the rotation speed (dust / foreign matter).
The sound quality changes with the rotation speed (scratch).
  • Dust / foreign matter

  • The surface of track, ball and roller is rough

  • Track surface, ball and roller surface scratch

Yay Small bearing
  • The surface of track, ball and roller is rough

Yap – Yap Intermittent and regular occurrence
  • Contact with sealing ring

  • Contact with retainer and sealing cover

Whine
Didi
Roar
Due to the change of rotation speed, the size and height change. The sound becomes louder when turning at a specific speed. There are also similar alarms or flute sounds.
  • Resonance, poor fit (poor shaft shape)

  • Track surface deformation

  • Track surface, ball and roller corrugations (it is normal for large bearings to have a slight sound)

Creak, creak Feel when rotating manually
  • Track surface scratch (regular)

  • Scratch of ball and roller (irregular)

  • Dust / foreign matters, track surface deformation (partial clearance is negative)

Rumble
Large bearing, small bearing: continuous sound at high speed
  • Track surface, ball and roller surface scratch

Woo –
Buzzing –
Instant stop when power is cut off
  • Motor electromagnetic sound

Squeak squeak Irregularity occurs (not due to the change of rotation speed), mainly small bearings
  • Mixed with dust / foreign matters

Jingle jingle
Tapered roller bearings, large bearings, small bearings: regular and high-speed continuous sound
  • If the sound of the retainer is clear, it is normal

  • If the grease is not suitable at low temperature → soft is good

  • Operation due to internal wear of retainer, insufficient lubrication and insufficient bearing load.

Hey, wow It is obvious at low speed and continuous sound at high speed
  • Impact sound inside the retainer, insufficient lubrication. The abnormal sound disappears after reducing the internal clearance or preloading.

  • In case of all rollers, the impact sound between rollers occurs.

Bang Bang Large metal impact sound, low-speed thin-walled large bearing (TTB), etc.
  • Rotating body tearing sound

  • Track wheel deformation

  • Squeak

Jangling The main reason is that the cylindrical roller bearing changes due to the change of rotation speed. When the sound is loud, metal sound can be heard. It will stop for a while after lubricating oil is replenished.
  • The lubricating oil is too thick

  • Excessive radial internal clearance

  • Insufficient lubricating oil

Installation sound Biting sound between metals, sharp sound
  • Bite between roller and retaining edge of roller bearing

  • The internal clearance is too small

  • Insufficient lubricating oil

Yay Irregular sound from small bearings
  • Bubble cracking sound in lubricating oil

Snap, snap, snap Irregular squeak
  • Slip of mating part

  • Squeak on mounting surface

  • Squeaking of keys, etc

Generally speaking, the sound pressure is too high
  • The surface of track surface, roller and ball is rough

  • Deformation of track surface, roller and ball due to friction

  • Excessive internal clearance due to friction

► loud metal noise

  • Cause 1: abnormal load, countermeasures: correct fit, study bearing clearance, adjust and load, and correct the position of housing shoulder.
  • Cause 2: poor installation. Countermeasures: improve the machining accuracy of shaft and shell, and improve the installation accuracy and installation method.
  • Cause 3: insufficient or unsuitable lubricant. Countermeasures: Supplement lubricant and select appropriate lubricant.
  • Cause 4: the rotating parts are in contact. Countermeasure: modify the contact part of the curved path seal.

► regular noise

  • Cause 1: indentation, corrosion or scar on the rolling surface caused by foreign matters. Countermeasures: replace the bearing, clean relevant parts, improve the sealing device and use clean lubricant.
  • Cause 2: (after steel carburizing) surface deformation, countermeasures: replace the bearing and pay attention to its use.
  • Cause 3: the raceway surface is stripped, countermeasure: replace the bearing.

► irregular noise

  • Cause 1: the clearance is too large. Countermeasures: study the fit and bearing clearance, and modify the preload.
  • Cause 2: invasion of foreign matters, countermeasures: study and replace bearings, clean relevant parts, improve sealing devices and use clean lubricants.
  • Cause 3: spherical surface damage and peeling, countermeasure: replace the bearing.

30 causes of bearing noise

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  • 1. Impurities in grease;
  • 2. Insufficient lubrication (oil level is too low and improper storage leads to oil or grease leakage through the seal);
  • 3. The bearing clearance is too small or too large (manufacturer’s problem);
  • 4. Impurities such as sand or carbon particles are mixed into the bearing to play the role of abrasive;
  • 5. Dirt such as water, acid or paint is mixed into the bearing to corrode;
  • 6. The bearing is flattened by the seat hole (the roundness of the seat hole is not good, or the seat hole is not straight);
  • 7. The sizing block on the bottom surface of the bearing seat is uneven (resulting in seat hole deformation and even crack of the bearing seat);
  • 8. There are sundries in the bearing seat hole (residual chips, dust particles, etc.);
  • 9. Eccentric sealing ring (contact with adjacent parts and friction);
  • 10. The shaft bears additional load (the shaft bears axial tightness, or there are two fixed end bearings on one shaft);
  • 11. The fit between the bearing and the shaft is too loose (the diameter of the shaft is too small or the tightening sleeve is not tightened);
  • 12. The clearance of the bearing is too small and too tight during rotation (the tightening sleeve is tightened too much);
  • 13. Bearing noise (caused by roller end face or steel ball slipping);
  • 14. The thermal elongation of the shaft is too large (the shaft bears static indeterminate axial additional load);
  • 15. The shaft shoulder is too large (touching the seal of the bearing and causing friction);
  • 16. The shoulder of the seat hole is too large (it distorts the seal of the bearing);
  • 17. The clearance of labyrinth seal ring is too small (friction with shaft);
  • 18. The teeth of the lock washer are bent (touching the bearing and rubbing);
  • 19. The position of the oil slinger is inappropriate (touching the flange cover and rubbing);
  • 20. There are pressure pits on the steel ball or roller (caused by knocking the bearing with a hammer during installation);
  • 21. Bearing noise (interference from external vibration source);
  • 22. The bearing is discolored and deformed by heating (caused by removing the bearing by heating with a spray gun);
  • 23. The shaft is too thick, which makes the actual fit too tight (resulting in excessive bearing temperature or noise);
  • 24. The diameter of the seat hole is too small (resulting in excessive bearing temperature);
  • 25. The diameter of bearing seat hole is too large and the actual fit is too loose (bearing temperature is too high – outer ring slips);
  • 26. The bearing seat hole becomes larger (the bearing seat hole of non-ferrous metal is supported larger, or becomes larger due to thermal expansion);
  • 27. The cage is broken.
  • 28. The bearing raceway is rusty.
  • 29. Wear of steel ball and raceway (unqualified grinding or bumping of products).
  • 30. The ferrule raceway is unqualified (manufacturer’s problem).

Detection method and instrument of abnormal sound of bearing

At present, there are two ways to detect abnormal sound of bearing. One is noise detection based on acoustics, the other is vibration detection.
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(1) Noise detection method:
In the silencing environment where the basic noise is less than 20dB, high-quality microphone is used to extract the bearing sound pressure signal at a certain distance and direction, and the abnormal sound components are extracted by a certain analysis method. It is a direct measurement method of abnormal sound.
(2) Vibration detection method:
It is an indirect detection method of abnormal sound, which can be divided into qualitative detection method and quantitative parameter detection method. Among them, the qualitative detection method is divided into monitoring abnormal sound method and observing vibration waveform method. Quantitative parameter detection method refers to using the measured parameter values related to abnormal sound in the measured bearing vibration signal, such as vibration peak and wave peak factor to evaluate the abnormal sound of bearing.
(3) Measuring instrument for measuring abnormal sound of bearing:
There are many measuring instruments for measuring the abnormal sound of bearings, such as bant-1 bearing abnormal sound monitor of Hangzhou bearing test and Research Center; S092 bearing vibration (abnormal sound) measuring instrument of Shanghai Bearing Technology Research Institute; S0910 – Ⅲ jointly developed by Luoyang Bearing Research Institute and Dalian bearing instrument factory. These bearing measuring instruments can not only measure the effective value of bearing vibration, but also measure the peak value, peak factor and pulse number reflecting the abnormal sound parameters of bearing.

Correct storage method of bearing

  • 1. Keep the original packaging and do not open it arbitrarily. If the packaging is damaged, it must be opened, carefully cleaned and repainted.
  • 2. The relative humidity of the storage room shall not exceed 60%, and the temperature difference shall not be too large. The bearings placed in the original packaging can be stored for several years. For sealed bearings or bearings with dust covers, the lubrication characteristics of the grease filled in the bearings may be reduced after long-term storage.
  • 3. The storage room shall also be protected from vibration and shaking. The bearings not stored in the original packaging shall be properly stored. It is strictly prohibited to put the bearings together with corrosive things to prevent corrosion and pollution.
  • 4. Large rolling bearings can only be placed horizontally during storage, and the sides of the inner and outer rings should be supported. If it is stored upright, permanent deformation may be caused due to the heavy inner and outer rings and rolling parts and the relatively thin inner and outer ring walls.

Source: China Bearing Manufacturer – Yaang Pipe Industry (www.steeljrv.com)

(Yaang Pipe Industry is a leading manufacturer and supplier of nickel alloy and stainless steel products, including Super Duplex Stainless Steel Flanges, Stainless Steel Flanges, Stainless Steel Pipe Fittings, Stainless Steel Pipe. Yaang products are widely used in Shipbuilding, Nuclear power, Marine engineering, Petroleum, Chemical, Mining, Sewage treatment, Natural gas and Pressure vessels and other industries.)

If you want to have more information about the article or you want to share your opinion with us, contact us at sales@steeljrv.com

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