Evaluation of a failed bearing with flange contact Figure 78 shows a functioning flange surface. 3.4.1 Damage to the ribs and roller end faces of the roller bearing model 3.4.1.1 Scratches caused by foreign particles: the arc-shaped rubbing on the rib surface and the roller end faces (especially in tapered roller bearings) Injury, see figures 79 and 80. The scratch depth in the rib area is related to the radius of the large end face of the rolling element embedded in the external particles. Reason: The external hard particles in the lubricant have entered the contact area between the roller end face and the rib. Remedy: Improve lubricant cleanliness. Adhesion phenomenon at the contact point of the failed bearing rib: There is partial or large area welding and deep scratches in the contact area of u200bu200bthe rib and the roller end surface, see Figures 81 and 82. There is also lubricant coking in this area. Often related to excessive load. Reason: Insufficient lubrication under high load and high speed (the amount of lubricant is too small or the working viscosity is too low) Insufficient lubrication under high load and low speed, there is no elastic fluid dynamic pressure lubricating film between the roller end face and the rib. The preload of the sub-bearing is too high. Excessive preload due to thermal expansion, such as roller tilt due to raceway wear, ring tilt or insufficient adjustment, see Figure 81. The axial load of the cylindrical roller bearing is too high because of the mating surface 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 lubricant quantity). Ensure the correct adjustment of the wear of the rib contact area of u200bu200bthe bearing. Phenomenon (1): In rolling bearings, poor lubrication can firstly pass through the sliding of the roller end/rib To judge. In severe cases, it will cause the aforementioned stalemate 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. There are often bumps on the end of the roller. If it is a tapered roller bearing, it will cause a decrease in preload or an increase in axial clearance. For example, it will increase the operating noise when subjected to a load that changes in direction. Due to the geometric relationship, the amount of wear on the contact area of u200bu200bthe tapered roller bearing rib will be converted into an axial clearance of about B/d. Rib wear can also reflect the wear of the raceway or the outer diameter of the roller. Reason: Inappropriate lubrication (type, quantity) Contaminated lubricant remedy: Try to ensure cleanliness as much as possible. Choose suitable lubricants (viscosity, EP additives) and ensure adequate supply of ribs. Phenomenon (2): All or part of the supporting ribs are broken or chipped, as shown in Figure 85. Reason: The axial load exceeds the limit and the rib support is insufficient, as shown in Figure 20. Secondary damage caused by the axial impact load cage and rolling element fracture. Installation damage remedial measures: Ensure that the design load of the good rib support is kept within the design limit. Installation Instructions.