Not all damaged bearings can be repaired, but for each damaged bearing, before considering repairing or replacing a new NTN imported bearing, the cause and degree of damage must be evaluated to avoid or reduce further damage.
There are many causes of bearing damage, such as improper installation, dirt intrusion or moisture intrusion, which are common causes of early bearing damage. Analysis of common damage causes of NTN imported bearings and corresponding preventive measures to prolong the service life of NTN imported bearings.
A. Improper operation:
Improper installation, operation or disassembly may cause deformation or damage to the cage
Precautions: use appropriate operation, installation and disassembly tools
B. Insufficient lubrication:
Insufficient or improper lubrication may lead to component scratch or severe NTN inlet bearing deformation
Preventive measures: improve the lubrication system and supplement or replace the lubricant regularly and properly
C. Rust and corrosion:
Contact with water may cause corrosion and rust of NTN inlet bearing elements. The corroded NTN inlet bearing may cause spalling during operation
Preventive measures: regularly check the seal to ensure good sealing effect, and correctly store NTN imported bearings
Energizing the NTN inlet bearing during rotation may cause grooves or nicks. When the NTN inlet bearing is stationary, improper grounding of electrical operation will cause slight burns
Precautions: before welding parts other than NTN inlet bearing, reduce or avoid current passing through NTN inlet bearing through appropriate grounding connection
E. External materials:
Abrasive particle contamination and debris intrusion may cause wear, scratches and dents on the working surface of NTN inlet bearing
Precautions: remove invading particles and debris, change lubricant and check sealing system
Eccentricity, inclination or excessive load may lead to geometric stress concentration or surface spalling
Preventive measures: accurately process NTN imported bearing seat and shoulder
For the periodic maintenance and operation of NTN imported bearing equipment and the replacement of peripheral parts, when the search and inspection of the disassembled bearing is suspended, it is necessary to judge whether the secondary bearing parts can be reused and record the good or bad application conditions.
Secondly, check the raceway surface, rolling surface and joint surface of NTN imported bearing and the wear condition of the standoff frame for damage and abnormal conditions. In particular, check the running track of the raceway surface.
To judge whether the bearing can be used again, we should think about the level of bearing damage, mechanical function, priority, operation premise, search and inspection cycle, etc.
If NTN imported bearing is found damaged or abnormal, please find out the notice and formulate countermeasures according to the phenomenon of bearing damage.
In addition, the search and inspection results show that if there are the following defects, the bearing can no longer be used. It is necessary to replace the new NTN imported bearing.
1. Maintenance of NTN imported bearing: in order to maintain the original performance of the bearing in good condition for as long as possible, it is necessary to maintain and repair in order to prevent accidents, ensure the reliability of operation and improve productivity and economy.
Maintain the operation standard of corresponding mechanical operation conditions and carry out it regularly. The contents include monitoring the operation status, replenishing or changing the lubricant, and regular disassembly inspection.
The maintenance items during operation include the rotating sound, vibration, temperature, lubricant state of NTN imported bearing, etc.
2. Maintenance of NTN imported bearing: cleaning of bearing: when removing the lower bearing for maintenance, first record the appearance of the bearing, confirm the residual amount of lubricant, and clean the NTN imported bearing after sampling the lubricant for inspection. As a cleaning agent, gasoline and kerosene are commonly used.
The removed NTN imported bearings are cleaned in coarse cleaning and fine cleaning. They are placed in the container respectively. First, put the metal mesh bottom so that the bearing does not directly contact the dirt of the container.
During rough cleaning, if NTN inlet bearing rotates with dirt, it will damage the rolling surface of NTN inlet bearing, which should be paid attention to. In the coarse cleaning oil, use a brush to remove the grease and adhesion. After it is roughly clean, turn to fine cleaning.
Fine cleaning is to carefully clean the NTN imported bearing while rotating in the cleaning oil. In addition, the cleaning oil should also be kept clean.
3. Maintenance and judgment of NTN imported bearing: in order to judge whether the disassembled bearing can be used, it should be checked after the bearing is cleaned. Check the state of the raceway surface, rolling surface and mating surface, the wear of the cage,
the increase of the clearance of the NTN inlet bearing and the damage related to the decline of dimensional accuracy. If the outer ring supports the inner ring smoothly, use one hand to confirm whether the inner ring supports the small bearing smoothly.
Tapered roller bearings and other separable bearings can inspect the raceway surfaces of rolling elements and outer rings respectively.
Since large NTN imported bearings cannot be rotated by hand, pay attention to the appearance of rolling elements, raceway surfaces, cages, edge retaining surfaces, etc. the higher the importance of NTN imported bearings, the more careful the inspection is.
1. The resultant force of force application shall pass through the axis of NTN imported bearing as far as possible, which requires that the force application point shall be uniform, symmetrical and stable, and the force shall be applied through the spherical surface or parallel to the axis.
2. The force should be applied stably and evenly without impact, which requires the use of oil pressure or tools that can apply stable tension or pressure. When hammering has to be used,
it should also be buffered by soft metal without chip falling, such as copper sleeve, and the knocking force should be as light as possible. Hammer with a copper bar or hammer.
3. Avoid applying force through the rolling element, which requires applying force through the inner ring when installing and removing the inner ring (shaft ring) and through the outer ring when installing and removing the outer ring).
4. The drag force shall be maintained to a proper extent. For example, when installing the NTN imported bearing,
the force shall be stopped when the bearing is just installed in the correct position to ensure that the end face of the ferrule (washer) is against the seat hole or the shoulder end face of the shaft, which can not be squeezed too tightly or installed in place.