Cause analysis of bearing service life of ina rolling mill
Cause analysis of bearing service life of ina rolling mill
2022年3月23日
Low Magnification Defect of Bearing Steel
Low Magnification Defect of Bearing Steel
2022年3月23日

How to judge the failure of bearing grease in use

There are many indicators required for the performance of bearing grease, mainly colloidal stability (oil separation), mechanical stability (100000 shear tests to extend the working cone penetration value) and oxidation stability. The comprehensive result of these three indicators is the service life of the bearing.How to judge the failure of bearing grease in use

How to judge the failure of bearing grease in use

  • The lubricating grease running in the bearing is damaged by mechanical force, which breaks and shortens the fiber of the thickener and reduces the ability to maintain the structure of the lubricating grease, that is, the consistency change.How to judge the Failure of Bearing grease in use
  •  If the consistency change is very likely to cause loss from the working surface, and the lubricating grease will be affected by the temperature rise during operation, The base oil will be reduced by evaporation, or the oil content of the grease will be reduced due to the loss of oil separation due to the destruction of the colloid of the grease, and there is also the possibility of oxidative deterioration.How to judge the failure of bearing grease in use
  • Therefore, for bearing grease, if the content of base oil in the grease is lower than 60% – 70% (i.e. 30% – 40% loss of base oil due to evaporation or oil separation), the lubricating capacity will be reduced or even lost, resulting in bearing operation failure. How to judge the Failure of Bearing grease in use
  • At the same time, the consistency of the grease will be reduced and deteriorated due to oxidation, which will affect the operation of the bearing.How to judge the failure of bearing grease in use
  • Raceway sound of bearing and its control method raceway sound is a smooth and continuous sound made by the rolling body rolling on the raceway surface when the shaft is running. It is a unique basic sound that will occur in all bearings. The general bearing sound is the sound of raceway plus other sounds. How to judge the Failure of Bearing grease in use
  • The greater the rigidity of the bearing pedestal, the lower the sound pressure level of the raceway sound. If the radial clearance is too small, the sound pressure level and dominant frequency of raceway sound will increase sharply with the decrease of radial clearance.How to judge the Failure of Bearing grease in use

 

  • Bearing fatigue failure is a surface form of failure, which is mainly manifested in the initiation, propagation and fracture process of fatigue crack, and the long-term impact of load failure under alternation.How to judge the failure of bearing grease in use
  • 1. Reason: the accuracy of the integral eccentric bearing is low. Method: select the bearing with the specified accuracy grade.How to judge the Failure of Bearing grease in use
  • 2. Cause: the main shaft is bent or the box hole is not concentric. Method: repair the main shaft or box.How to judge the Failure of Bearing grease in use
  • 3. Cause: the belt is too tight. Method: adjust the belt to make it elastic properly
  • 4. Cause: poor lubrication method: select the specified brand of lubricating materials and clean them properly
  • 5. Cause: low assembly quality method: improve assembly quality
  • 6. Cause: the inner shell of the bearing runs. Method: replace the bearing and related worn parts
  • 7. Method of excessive axial force: clean and adjust the clearance of sealing ring between 0.2 ~ 0.3mm, correct the diameter of impeller balance hole and verify the static balance value.How to judge the Failure of Bearing grease in use
  • 8. Bearing damage method: replace the bearing
  • The methods to control the sound of raceway are: select low-noise bearings, that is, bearings with small waviness, and carefully select the service conditions. Raceway noise often affects the noise of the whole machinery. Reducing raceway noise can reduce the noise of the whole machinery.How to judge the failure of bearing grease in use
How to judge the failure of bearing grease in use
  • The load trace indicates that the roundness of the bearing chamber may be out of tolerance, resulting in the ball in the non load area also bearing the load. In this way, the bearing will be heated and noisy after operation. 
  • If the load track is found after removing the Thin-walled bearing, the roundness of the bearing chamber needs to be adjusted. The roundness of geometric tolerance is out of tolerance.How to judge the Failure of Bearing grease in use
  • 3. The residual clearance of IKO bearing is too small
  • Generally speaking, normal thin-walled bearings always have a certain residual clearance during operation, which will be distributed in the non load area. The curve of the influence of residual clearance on the service life of rolling bearing. When the remaining clearance is too small, the bearing will be very easy to be stuck, resulting in early failure.
  •  The performance of these failed bearings before burning is noise and heating, and the load track on the surface of Thin-walled bearing raceway may cause the residual clearance of IKO bearing to be too small. How to judge the Failure of Bearing grease in use
  • The factors may include: too tight fit of inner ring, too large temperature difference between inner and outer rings, etc. Adjustment and modification shall be carried out in time.
  • The common fault of IKO bearing is the contact dry friction between bearing and journal. Serious dry friction will lead to the increase of clutch bearing temperature and lubricating oil temperature, the decrease of viscosity and bearing capacity, resulting in malignant accidents such as sticking pad and burning shaft.
  • And even damage the equipment and threaten people. Therefore, the research on real-time monitoring and fault diagnosis of IKO bearing has attracted extensive attention.
  • At present, there are the following commonly used fault diagnosis methods of clutch bearing.