Failed Bearing Evaluation for Rib Contact Figure 78 shows a functioning rib surface. 3.4.1 Damage to rib and roller end face of roller bearing types injury, see Figures 79 and 80. The depth of the scratch in the rib area is related to the radius of the large end face of the rolling element in which the foreign particles are embedded. Reason: External hard particles in the lubricant enter the contact area between the roller end face and the rib. Remedy: Improve lubricant cleanliness. Adhesion at the rib contact of a failed bearing: Partial or extensive welding and deep scratching in the contact area between the rib and the roller end face, see Figures 81 and 82. There is also lubricant coking in this area. Often associated with excessive load. Causes: Insufficient lubrication at high load and high speed (too little lubricant quantity or too low operating viscosity) Insufficient lubrication at high load and low speed, no elastic hydrodynamic lubricant film between roller end face and rib tapered roller Preload of sub-bearings too high Excessive preload due to thermal expansion such as roller inclination due to raceway wear, ring inclination or insufficient adjustment, see Figure 81 Axial load of cylindrical roller bearings too high due to mating surfaces The inclination of the inner ring makes the axial load of the inner ring too high. Remedial measures: Improve lubrication (increase viscosity, EP additives, increase the amount of lubricant) Ensure the correct adjustment of the bearing to the wear of the rib contact area. Phenomenon (1): In rolling bearings, poor lubrication can first be caused by the sliding of the roller end face/rib to judge. In severe cases, it can lead to the aforementioned sticking phenomenon. However, in all cases the contact area will have wear characteristics. This can be clearly seen on the cross-sectional diagram of the roller end face or rib, see Figure 83. Roller end faces often have bulges. In the case of tapered roller bearings, this will result in reduced preload or increased axial clearance. For example, the operating noise will increase when subjected to loads that change in direction. Due to the geometrical relationship, the amount of wear on the contact area of u200bu200bthe tapered roller bearing rib is converted into an axial clearance of approximately B/d. Rib wear can also reflect raceway or roller OD wear. Causes: Improper lubrication (type, quantity) Contaminated lubricant Remedy: Clean as much as possible Select suitable lubricant (viscosity, EP additives) and ensure adequate supply of rib fracture. Phenomenon (2): All or part of the supporting rib is broken or broken, see Figure 85. Cause: Axial load beyond limit Insufficient rib support, see Figure 20 Axial shock load Secondary damage due to cage and rolling element fracture Installation guide.