INA tapered roller bearing surface failure cause preventive measures

Is generally thought that to improve the working surface of system reliability engineering is an important sector of the bearing ( INA bearing job functions in the loss of designated, lead to failure or does not work as failure phenomenon called ( Bearing fault can be divided according to their normal failure and premature failure of the two, it mainly for pitting corrosion and fatigue cause of tapered roller bearing early failure analysis and put forward Suggestions for improvement and progress in bearing life and reliability. Bearing surface form of fatigue failure is a failure, main performance for fatigue crack initiation, expansion and fracture process, under alternating load generated by the fault of the long-term effects of the metal. Cracks in two aspects: first, on the surface, this is, tapered roller bearing in the process of moving contact, because in the work on the surface of the plastic deformation and strain hardening on the surface of the contact stress cyclical changes caused by the effect of external load, and finally on the inner surface of the small crack from the development, the formation of surface cracks, between the two because Xie into the lubricant on the surface of the work, the strength of open, serious blow on the wall, crack force to move forward; Second: from the surface, under the pressure of repeatedly, the surface contact, where initially exposed on the surface of a certain depth of crack, and along the surface direction Angle, to a certain depth, since on the surface of contact area, and beyond the surface, and the ultimate formation of corrosion, leaving a horse pit. On the surface, from surface cracks, these two goals ( Part carburizing, quenching and other surface heat treatment, after if have uneven hardness, organization, and the average internal stress and other adverse, the contact stress is generally have the opposite under the influence of ground fissures, if parts surface quality is poor, there is a defect ( Oxidation and decarburization) Poor lubrication, friction or from the surface crack. INA bearings after installation, in order to check whether installed correctly, check for running. Small mechanical can rotate with the hand, to confirm whether to rotate smoothly. Check project has caused by foreign bodies, scars, creasing seized up, due to bad installation, installation of seat processing bad moment is not stable, because the clearance is too small, installation error, seal friction caused by the torque is too big, and so on. If there is no abnormal can start power operation. Dynamic operation, from the beginning of the no-load speed, slowly up to the rated operating conditions. Test run to check the items, whether there is abnormal sound, tapered roller bearing temperature, lubricant leakage or discoloration, and so on. If discovery is unusual, should immediately stop, check machine, when it is necessary to remove the bearing inspection. 1, selection of shaft and the bearing chamber tolerance and control: after the bearing pressure should be flexible rotation without blocking. If there are any obvious rotation is not flexible, indicates the size of the shaft is too big, tolerance to downgrade. Such as taper roller bearing pressure into the shaft by hand after the rotation has obvious 'sasha vujacic' feeling, may be the shaft or shaft roundness tolerance is too big. When control the shaft and the bearing chamber tolerance so also want to control the roundness, at present many domestic manufacturers to control the tolerance, not to control the roundness. 2, bearing assembly way: because the bearing is high precision products, such as improper assembly is easy to cause damage to taper roller bearing channel, result in bearing damage. INA bearing in the assembly shall have a dedicated mold, not casually, only small circle of stress when pressure into the shaft, pressure can force the circle circle. Require the use of pneumatic or hydraulic assembly, touched up and down when pressed to outside the state level, such as with sloping channel by mechanical damage can lead to bearing, guide ring and the bearing. 3, the assembly to prevent foreign body: tapered roller bearing in loaded on the rotor dynamic balance when it is easy to dynamic balance of iron into the bearing inside, so it is best to install bearing before do dynamic balance. There are some manufacturers in order to convenient assembly, assembly in bearing indoor coated with some oil or grease lubrication effect, but usually operators good amount of it is hard to control, if oil or grease in the bearing interior storing up more, in the INA bearing rotates along axis to the bearing inside easily. Bearing chamber it is best not to apply oil or grease, if must apply to control shall not be storing up in bearing interior. 4, paint, rust prevention: paint rust is characterized by multiple in sealing type motor, the motor sound is very good, when it is assembled but put some time in the warehouse, the motor sound is very big, remove the taper roller bearing with serious rust phenomenon. Many manufacturers will think is a problem of bearing before, after our propaganda, motor factory now have realized mainly is a question of insulating varnish. Acid varnish comes out of the problem is mainly due to the formation of corrosive substances under certain temperature and humidity, the INA bearing channel after corrosion result in bearing damage. The problem now is only to choose good insulating paint, after drying and ventilation assembly after a period of time.