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KOYO bearings in operation cannot be directly observed, but through conditions such as noise, vibration, temperature, lubricant is multi-user aware bearing exception. Representative cases of bearing damage;
1, crack
Some of the gaps have cracks. The reason: host too great a shock load, combined with KOYO bearings of spindle interference; also has a larger split friction cracking installation accuracy poor misuse (oxalis corymbosa, into large foreign body) and friction cracking.
Countermeasures: should check the conditions of use, and that suitable interference and examination materials, improved installation and how to use it, check the lubricant to prevent friction and crack.
2, the surface metal Raceway-split
Run split. Split was evident after the bump. Because KOYO bearing rolling element and the inner and outer ring raceways are subjected to cyclical fluctuation load on the surface, resulting in a cycle of contact stress. When the stress cycle count reaches a certain number, in the rolling elements or on the inner and outer ring raceways face fatigue peeling. If the bearing load is too large, will exacerbate this fatigue. In addition, the bearing is not being installed, axis bending, also have a roller stripping phenomenon.
Countermeasures: should re-examine the conditions of use and select the KOYO bearings and clearance, and check the axial and machining precision of bearing box, installation method, lubricant and lubrication method.
3, burn
KOYO bearings heat discoloration, which burns cannot be rotated. Causes of Burns is generally insufficient lubrication, lubricant quality does not meet the requirements, or metamorphic, and bearing Assembly too tight. Clearance is too small, and too much load (preload) roller deflection.
Strategy: choose the appropriate clearance (or increase the clearance), to check the type of lubricant, ensure that the injected amount, check the conditions of use, in case the positioning errors, improving the bearing Assembly method.
4, cage broken
Loose or broken rivets, roll of broken. The reason: torque through overloading, insufficient lubrication, frequent changes in speed, vibration, bearing in the tilted installation into foreign objects.
Response: to find the use conditions and suitability of lubrication, note the use of KOYO bearings, study the suitability of selection of cage and bearing boxes of rigid load requirements.
5, creep
Inner diameter or od surface slip, causing mirror or change color, sometimes stuck. Reason: combined with insufficient interference fit, sleeve tighten enough, unusual heat, the host overloaded.
Response: to re-examine whether the interference fit, check the conditions of use, check the accuracy of the shaft and housing.
6, rust corrosion
In part or in whole the surface rust, rolling lines rusted. Reasons: inadequate custody status bad, improper packaging, rust, acid solvent such as intrusion of moisture, direct handle bearings.
Response: in custody to prevent rust and oil packaging are not regularly again on a regular basis, enhanced sealing performance, periodically check the oil, oil failure or deterioration of a timely replacement to correct bearing.
7. bearing indentation
Injury status: bite into the metal powder, foreign body, turned in the Raceway surface or dents on the surfaces. Because of shocks installed, roller spacing interval formed on concave (Brinell hardness indentation).
Reason: foreign material, such as metal powders to bite into. Assembly time or during transport excessive impact loading.
Measures: shock bushings. Improvement of sealing device. Filter oil. Improvement of Assembly and method of use.
8. bearing wear
Injury status: the so-called wear is on Raceway surface due to friction or rolling surface, roller surface, concave wear collar and cage.
Cause: the intrusion of foreign bodies, rust caused Eclipse development. Poor lubrication. Due to the rolling elements caused by the irregular movement of slip.
Measures: improvement of sealing device. Clean the bearing box. Full filter oil. Check lubricant and lubrication method. To prevent misalignment.
9. bearing false Brinell indentation
Injury status: micro-vibration during the rolling element and the Raceway round of the contacts wear has evolved due to vibration and shaking, tired of Brinell indentation marks.
Cause: during transport of medium bearing in vibration when stopped and swing. Small amplitude of the swing movement. Poor lubrication.
Measures: biting during transport be fixed on the shaft and the bearing box. When inner ring and outer ring should be packed separately. Added preloading vibration reduction. Use appropriate lubricants.
10. the bearings burn
Injury status: roller wheels, rolling elements and cage fever until the discoloration, dramatically softens in the rotation, cladding, and breakage.
Reason: poor lubrication. Excessive load (preload). Excessive speed. Clearance is too small. Water, intrusion of foreign bodies. Poor precision of the shaft, housing, shaft deflections.
Measures: study on the lubricant and lubrication method. Selection of the correct bearing. Research collaboration, the bearing clearance and preload. Improvement of sealing device. Check the precision of the shaft and housing. Improvement installation method.
11. bearings are rusted, corroded
Injury status: rust and corrosion of the bearing Raceway round, rolling surface pit-like rust, full of rust and corrosion.
Cause: water, corrosive substances (such as paint, gas), invade. Lubricants are not appropriate. Accompanied by water droplets due to the condensation of water vapor. Stopped when the high temperature and humidity. Poor transport heavy rust. Custody status is not appropriate. Use is inappropriate.
Measures: improvement of sealing device. Study on lubrication method. When stops Rust prevention measures. Methods of improving the custody. To pay extra attention when using.
12. bearing color
Injury status: response due to rising temperatures and lubricants, roller wheels and rolling elements and cage to color.
Reason: poor lubrication. Hot oil and lubricants reflect caused. Temperature rise.
Measures: improvement of lubricating methods.
As long as we avoid a situation above, scheduled maintenance bearings, will function to ensure the life and performance of the bearing.
| Product Model | Inside Diameter | Outside Diameter | Thickness |
| NNU4988 NTN | 440 | 600 | 160 |
| NNU4984K NTN | 420 | 560 | 140 |