Rolling bearings are mass-produced mechanical parts, and the manufacturing accuracy requirements are very strict. The degree of technical specialization is very high. The most common failure is severe fever. If it is newly installed or after cleaning and oil change, the temperature rises rapidly as soon as it is operated, and there is a serious fever, but there is no abnormal sound or vibration during operation, the reason is most likely that too much grease has been added, and a certain amount should be added appropriately. of grease.

        If there is a severe fever and the bearing is "stuck", the possible reason is that the bearing caps of the two shafts push the bearing outer rings too tightly and do not leave enough inter-axis clearance as required. It is caused by the shaft elongating due to the rising temperature. At this time, it should be adjusted appropriately. Special attention should be paid to tapered cylindrical bearings.

        In some cases, the fit between the inner ring of the bearing and the shaft is too tight, causing the inner ring to expand; or the fit between the bearing seat and the outer ring of the bearing is too tight, causing the outer ring to be compressed, deformed and cracked. For the former, if the interference dimension left when machining the shaft is too large, you can remove the bearing, grind the journal to the appropriate assembly size, and assemble it separately. The latter often occurs on split bearing seats, making the bearing seat more "flexible". You can add one or two layers of paper pads to the opposite sides of the bearing seat to eliminate the fault. In addition, if dust particles and impurities enter the raceway of the rolling bearing with the grease, "stuck" phenomenon may also occur. 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 then there is a dry friction noise or irregular impact sound when listening with a metal rod, it may be due to lack of oil, or it is not clean, or it may be due to the rolling of the bearing. If any parts are damaged, they should be disassembled and cleaned, and the oil should be changed or the bearings should be replaced.

        4. When there are any defects in the rolling part of the bearing, it must be replaced?

        ①Rust. If the bearing is out of service and gets damp or there is water in the parking lot, rust spots and other rust will appear on the surface of the rolling element or raceway.

        ②Indentation. When hard objects enter the raceway, pits are often pressed out on the surface of the raceway or raceway body. Not only will there be noise or impact during operation, but excessively large dents will also cause vibration and severe bearing heating.

        ③The bearing diagram 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 burst and damage the inner and outer rings of the bearing, and the moving ring of the thrust bearing will be crushed and broken.

        ④Fatigue peeling on the raceway surface. If used improperly, this normal wear and tear will be accelerated rapidly.

        ⑤The cage is broken. Basically it's a matter of material and manufacturing. Sometimes, the cage is damaged during installation, which can also cause premature breakage.

         ⑥The rolling elements are broken. There will definitely be loud noises and even vibrations during operation, mostly due to improper materials or heat treatment.

         ⑦Current corrosion. During electric welding, if current passes through the bearing, it will generate sparks and cause local burns on the raceway body. Therefore, during welding, the "ground wire" of the welding must be kept as close as possible to the welding point, and the welding current must not be allowed to pass through the bearing.

         ③The wear is seriously beyond the limit. A serious fever occurs during operation, causing abnormal noise and vibration, because the gap has increased at this time. When dust enters and the surface is scratched, the wear will be faster.

        In addition, if the dimensions are improperly matched during processing, causing "inner circle" or "outer circle", it will also cause noise, high temperature and vibration. It is easier to find a bearing running in the inner circle because the inner ring of the bearing is "loose" on the shaft; if the bearing is running in an outer circle, you need to carefully check the outer ring of the bearing or the inner ring of the bearing seat to find traces of mutual sliding between them.

         Bearing repair is only considered under the following circumstances, namely:

       (1) The main failure modes of a large number of bearings of the same type used in large factories are wear, fatigue or fretting abrasion of the rolling surfaces. In particular, the damaged parts are mostly cages or rolling elements, and the rings or washers still need to be repaired. value;

        (2) Large and extra-large bearings are on the verge of failure or have failed but the parts have not been seriously damaged, or precious bearings must try to extend their useful life.