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Common fault repair and economic of rolling bearing
Source: | Author:hardware-100 | Published time: 2014-08-15 | 597 Views | Share:
Rolling bearing is a mass-produced mechanical part with strict manufacturing accuracy and high degree of technical specialization. The more common fault is serious fever.

Rolling bearing is a mass-produced mechanical part with strict manufacturing accuracy and high degree of technical specialization. The more common fault is serious fever. If it is newly installed or after cleaning and changing the oil, it will rise rapidly as soon as it runs, with serious fever, and there is no abnormal sound or vibration during operation, the reason is most likely that too much grease is added, and a certain amount of grease should be added appropriately.

In case of serious fever, if the bearing is "stuck", the possible reason is that the bearing covers of the two shafts push the outer ring of the bearing too tightly, do not leave enough clearance between the shafts as required, and the temperature rise during operation causes the shaft to elongate. At this time, it should be adjusted appropriately. For tapered bearings, special attention should be paid.

In some cases, the fit between the bearing inner ring and the shaft is too tight, so that the inner ring expands; Or the bearing seat and the bearing outer ring are matched too tightly, so that the outer ring is pressed and deformed to produce cracks. For the former, if the interference size left during shaft processing is too large, remove the bearing, polish the journal to the proper assembly size and assemble it separately. The latter often occurs on the split bearing seat, making the bearing seat "flexible". One or two layers of paper pads can be added on the split surface of the bearing seat to eliminate the fault. In addition, if dust particles and impurities enter the raceway of rolling bearing with lubricating grease, there may also be "stuck" phenomenon. Once it occurs, clean and change the oil.

If the fever appears on the rolling bearing after it has been running normally for a period of time, and there is dry friction noise or irregular impact sound when touching with the metal rod, it may be lack of oil, unclean, or the rolling part of the bearing may be damaged. It should be disassembled and cleaned for oil change or bearing removal and replacement.

4. What defects must be replaced when the rolling part of the bearing appears?

① Rust. When the bearing is out of service, it is affected by moisture or there is water in the mooring, resulting in rust spots and other corrosion on the surface of the rolling element or raceway.

② Indentation. When hard objects enter the raceway, pits are often pressed out on the surface of the raceway or raceway body. Not only noise or impact sound occurs during operation, but also excessive pits will produce vibration and serious fever of bearings.

③ The bearing is broken. In addition to manufacturing reasons, if the interference size of the shaft is too large and the assembly method is improper, it will also expand and damage the inner and outer rings of the bearing, and the moving ring of the thrust bearing will be pressed and broken.

④ Fatigue peeling of raceway surface. If used improperly, this normal wear will be accelerated rapidly.

⑤ Broken cage. It's basically a matter of material and manufacturing. Sometimes, the cage is damaged during installation, which will also cause premature fracture.

⑥ The rolling element is broken. There will be loud noise and even vibration during operation, mostly due to improper material or heat treatment.

⑦ Current corrosion. During electric welding, if the current passes through the bearing, a fever will produce sparks, causing local burns to the raceway body. Therefore, during electric welding, the "ground wire" of electric welding must be as close as possible to the welding point, and the welding current is not allowed to pass through the bearing.

③ Serious wear exceeds the limit. Severe fever during operation, resulting in abnormal noise and vibration, because the time gap has been enlarged. When dust enters, the surface is scratched and the wear will be accelerated.

In addition, if the size is not matched properly during processing, it will cause "inner circle" or "outer circle", which will also cause noise, high temperature and vibration. The inner circle of the bearing is easy to find because the inner ring of the bearing is "loose" on the shaft; When walking the outer circle, carefully check the outer ring of the bearing or the inner ring of the bearing seat to find the traces of mutual sliding between them.

Bearing repair should only be considered if:

(1) The failure forms of a large number of bearings of the same model used in large factories are mainly the wear, fatigue or fretting abrasion of the rolling surface. In particular, the damaged parts are mostly cages or rolling elements, and the rings or washers still have repair value;

(2) Large and extra large bearings are on the verge of failure or have failed without major damage to parts, or valuable bearings must try to prolong their effective service life.