Main Functions of Lubricants
Main Functions of Lubricants
2022年3月23日
How to judge the failure of bearing grease in use
How to judge the Failure of Bearing grease in use
2022年3月23日

Cause analysis of bearing service life of ina rolling mill

  • When judging whether the disassembled imported bearing can be reused, check it after ina bearing cleaning, and carefully check the state of raceway surface, rolling surface and mating surface, the wear of cage, whether the clearance of rolling mill bearing increases, and whether there are damages and abnormalities affecting the decline of dimensional accuracy. For non separable small ball bearings, use one hand flat end inner ring and rotate the outer ring to confirm whether it is smooth.

Cause analysis of bearing service life of ina rolling mill

  • For separate bearings such as bearings, the raceway surfaces of rolling elements and outer rings can be inspected respectively.
  • Since large 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 ina bearings, the more careful the inspection is.Cause analysis of bearing service life of ina rolling mill
  • When judging whether the bearing can be reused, it should be determined according to the damage degree, mechanical performance, importance, operating conditions, inspection cycle and other relevant factors of the bearing. However, if the following defects are found during the inspection, the rolling mill bearing can not continue to be used and needs to be replaced with a new bearing.Cause analysis of bearing service life of ina rolling mill
  • 1: On the surface, this is the effect of external load caused by the plastic deformation on the working surface and the periodic change of contact stress on the strain hardened surface during the rolling contact process of imported bearings, and finally the formation of surface cracks between the two from the developing inner surface of small cracks. Due to the lubricant on the working surface, the open force severely hits the wall and forces the crack to move forward;Cause analysis of bearing service life of ina rolling mill
  • 2: From the surface layer, under repeated pressure, the contact of the surface will initially produce cracks at a certain depth at the place where the surface is exposed, and from the angle along the surface direction to a certain depth, from behind the surface of the contact surface, and beyond the surface, and finally form corrosion stripping, leaving a horse pit.Cause analysis of bearing service life of ina rolling mill
  • From the surface, or from the cracks in the surface layer, these two objectives (carburization, quenching and other surface heat treatment of parts). If there are uneven hardness, microstructure, and non-uniform internal stress and other disadvantages, the contact stress is generally affected by the opposite underground cracks. If the surface quality of parts is poor, there is a defect (oxidation, decarburization), poor friction or lubrication, and from the surface cracks.Cause analysis of bearing service life of ina rolling mill
  • After the ina bearing is installed, in order to check whether the installation is correct, the operation inspection shall be carried out. Small machinery can be rotated by hand to confirm whether it rotates smoothly. The inspection items include poor operation caused by foreign matters, scars and indentation, unstable torque caused by poor installation and poor processing of mounting base, excessive torque caused by too small clearance, installation error and sealing friction, etc. If there is no abnormality, the power operation can be started.Cause analysis of bearing service life of ina rolling mill
  • Large machinery cannot rotate manually, so the power shall be cut off immediately after no-load start, and the machinery idles. Check whether there is vibration, noise, contact of rotating parts, etc. after confirming that there is no abnormality, enter the power operation.Cause analysis of bearing service life of ina rolling mill
  • Power operation, starting from no-load and low speed, slowly increase to the rated operation under the specified conditions. During the test run, the inspection items are whether there is abnormal sound, temperature change of railway bearing, leakage or discoloration of lubricant, etc. If any abnormality is found, stop the operation immediately, check the machinery, and remove the bearing for inspection if necessary.Cause analysis of bearing service life of ina rolling mill
  • The bearing temperature can generally be inferred from the external temperature of the bearing seat. However, it is more accurate to directly measure the temperature of the bearing outer ring by using the oil hole. The bearing temperature rises gradually from the beginning of operation, and the temperature is usually stable after 1 ~ 2 hours. If ina bearing is not installed properly, the temperature will rise sharply, resulting in abnormal high temperature. The reasons are too much lubricant, too small bearing clearance, poor installation, excessive friction of sealing device, etc. In the case of high-speed rotation, the wrong selection of railway bearing structure and lubrication mode is also the reason.Cause analysis of bearing service life of ina rolling mill
  • The rotation of the bearing is checked with a stethoscope, and there are strong metal noise, abnormal sound, irregular sound and other abnormalities. The reasons are poor lubrication, poor accuracy of shaft or bearing seat, bearing damage, foreign matter intrusion, etc.Cause analysis of bearing service life of ina rolling mill
  • There are two kinds of lubricants commonly used in rolling bearings: lubricating oil and grease. When the circumferential speed of the shaft is less than 4-5m / s, or the parts on the vehicle that cannot be lubricated with lubricating oil, they shall be lubricated with grease. The advantage of grease lubrication is that the sealing structure is simple, the grease is not easy to lose, and it is not affected by temperature. Adding grease once can be used for a long time.Cause analysis of bearing service life of ina rolling mill
  • The advantage of lubricating oil lubrication is low friction resistance and heat dissipation. It is mainly used for railway bearings with high speed and high working environment temperature. The brand of lubricating oil shall be selected according to the requirements of the vehicle manual, and shall be replaced in time after the vehicle maintenance cycle. After discharging the old oil, the mechanism shall be cleaned before adding new oil. The oil shall be added to the specified marking line or flush with the oil filler (depending on the specific structure and requirements of the vehicle), and no more oil shall be added.Cause analysis of bearing service life of ina rolling mill
  • Bearing is an important mechanical component. Whether the performance of a mechanical equipment can be brought into full play depends on whether the lubrication of the bearing is appropriate. It can be said that lubrication is a necessary condition to ensure the normal operation of INA Bearing. It plays an important role in improving the bearing capacity and service life of railway bearing. No matter what form of lubrication is adopted, lubrication can play the following roles in the bearing:Cause analysis of bearing service life of ina rolling mill
  • (1) Reduce the friction between metals and slow down their wear.Cause analysis of bearing service life of ina rolling mill
  • (2) The formation of oil film increases the contact area and reduces the contact stress.Cause analysis of bearing service life of ina rolling mill
  • (3) Ensure that the bearing can operate normally for a long time under high-frequency contact stress and prolong the fatigue life,
  • (4) Eliminate friction heat, reduce the temperature of bearing working surface and prevent burns.Cause analysis of bearing service life of ina rolling mill
  • (5) It can prevent dust, rust and corrosion.Cause analysis of bearing service life of ina rolling mill
  • Therefore, proper lubrication is very important for the normal operation of INA Bearing. The lubrication design of railway bearings mainly includes the determination of reasonable lubrication methods, the correct selection of lubricants, the quantitative calculation of lubricant dosage and the determination of oil change cycle.Cause analysis of bearing service life of ina rolling mill
Cause analysis of bearing service life of ina rolling mill