Carefully analyze the causes and measures of bearing damage.
 
The bearing cannot be directly observed during operation, but abnormalities in the bearing can be detected through conditions such as noise, vibration, temperature, and lubricant. Representative examples of bearing damage;

1. Crack defect

Some gaps have cracks. The reasons are: the impact load of the host is too large, and the interference fit between the main shaft and the bearing is large; There are also significant peeling friction that causes cracks; Poor accuracy during installation; Improper use (using a copper hammer, inserting large foreign objects) and friction cracks.

Countermeasure: The usage conditions should be checked, and appropriate interference and material inspection should be set to improve installation and usage methods. Lubricants should be checked to prevent friction cracks.

2. Metal peeling on the surface of the raceway

Stripping of the operating surface. After peeling, it shows obvious concave convex shape. The reason is that the rolling element of the bearing and the inner and outer raceway surfaces are subjected to periodic pulsating loads, resulting in periodic contact stresses. When the number of stress cycles reaches a certain value, fatigue peeling occurs on the working surface of the rolling element or inner and outer raceways. If the load on the bearing is too large, it will exacerbate this fatigue. In addition, improper installation of bearings, bending of shafts, and peeling of raceways can also occur.

Countermeasure: The usage conditions and selection of bearings and clearances should be re studied, and the machining accuracy, installation method, lubricant and lubrication method of the shaft and bearing box should be checked.

3. Burns

The bearing heats up and discolors, resulting in burns and inability to rotate. The causes of burns are generally insufficient lubrication, lubricating oil quality that does not meet requirements or deteriorates, and bearing assembly that is too tight. In addition, the clearance is too small and the load is too large (pre pressing is too large), causing the roller to tilt.

Countermeasure: Select appropriate clearance (or increase clearance), check the type of lubricant, ensure injection amount, check usage conditions to prevent positioning errors, and improve bearing assembly methods.

4. Cage shattered

Loose or broken rivets, broken rolling elements. The reasons are: excessive torque load, insufficient lubrication, frequent speed changes, large vibration, bearings installed in an inclined state, and foreign objects getting stuck.

Countermeasure: It is necessary to check whether the usage conditions and lubrication status are suitable, pay attention to the use of bearings, study whether the selection of retainers is appropriate, and whether the rigidity of the bearing box meets the load requirements.

5. Creep

The inner or outer diameter surface slips, causing mirror or discoloration, and sometimes gets stuck. The reasons include insufficient interference at the fitting, insufficient tightening of the sleeve, abnormal heating, and excessive load on the main engine.

Countermeasure: It is necessary to re study whether the interference fit is appropriate, check the usage conditions, and check the accuracy of the shaft and bearing box.

6. Rust corrosion

Partial or complete rusting on the surface, and linear rusting on rolling elements. The reasons are: poor storage condition, improper packaging, insufficient rust inhibitor, invasion of water, acid, solvents, etc., directly holding the bearings by hand.

Countermeasure: To prevent rusting during storage, regularly and irregularly repackage with oil, strengthen sealing performance, regularly check lubricating oil, replace unqualified or deteriorated oil in a timely manner, and use bearings correctly.

7. Bearing indentation

Damage state: Dents on the raceway or rotating surface caused by biting into small metal powders, foreign objects, etc. Due to the impact during installation, concave surfaces (Brinell hardness indentations) were formed at the spacing of the rolling elements.

Reason: Foreign objects such as metal powder bite in. Excessive impact load during assembly or transportation.

Measure: Impact the shaft sleeve. Improve the sealing device. Filter lubricating oil. Improve assembly and usage methods.

8. Bearing wear

Damage state: The so-called wear is caused by friction, resulting in wear on the raceway surface or rolling surface, roller end face, shaft ring surface, and concave surface of the retainer.

Reason: Development caused by foreign object intrusion, rusting, and electrical corrosion. Poor lubrication. Slipping caused by irregular movement of rolling elements.

Measure: Improve the sealing device. Clean the bearing box. Fully filter the lubricating oil. Check the lubricant and lubrication method. Prevent non linearity.

9. False Brinell indentation on bearings

Damage state: During micro vibration, wear develops at the contact area between the rolling element and the raceway wheel due to vibration and shaking, resulting in accumulated marks resembling Brinell indentation.

Reason: Vibration and oscillation of bearings during transportation when they come to a stop. A swinging motion with small amplitude. Poor lubrication.

Measure: Fix the shaft and bearing box during transportation. During transportation, the inner and outer rings should be packaged separately. Add preloading to reduce vibration. Use appropriate lubricants.

10. Burns on bearings

Damage status: The raceway wheel, rolling element, and cage rapidly heat up during rotation until discoloration, softening, deposition, and damage occur.

Reason: Poor lubrication. Excessive load (excessive preloading). The rotational speed is too high. The clearance is too small. The invasion of water and foreign objects. The accuracy of the shaft and bearing box is poor, and the deflection of the shaft is large.

Measure: Study lubricants and lubrication methods. Correct the selection of bearings. Study fit, bearing clearance, and preloading. Improve the sealing device. Check the accuracy of the shaft and bearing housing. Improve installation methods.

11. Rusting and corrosion of bearings

Damage status: Rust and corrosion of bearings include pitting rust on the surface of raceway wheels and rolling elements, as well as overall rust and corrosion.

Reason: Intrusion of water and corrosive substances (paint, gas, etc.). The lubricant is not suitable. Due to the condensation of water vapor, water droplets are attached. Stop rotating during high temperature and high humidity. Poor rust prevention during transportation. Improper storage status. Inappropriate use.

Measure: Improve the sealing device. Research lubrication methods. Rust prevention measures during shutdown. Improve storage methods. Be careful when using.

12. Bearing discoloration

Damage status: Due to temperature rise and lubricant reaction, discoloration of raceway wheels, rolling elements, and retainers.

Reason: Poor lubrication. The reaction with the lubricant causes hot oil immersion. The temperature rises significantly.

Measure: Improve lubrication methods.

As long as we avoid the above situations and regularly inspect the bearings, we can ensure the normal service life and performance of the bearings.