Evaluation of roller bearing rib contact Figure 78 shows a functioning rib surface. Damage to the ribs and roller end surfaces of roller bearings. Scratch phenomenon caused by foreign particles: arc-shaped scratches on the rib surface and roller end surfaces (especially in tapered roller bearings), 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 part of the rib: There is partial or large area welding and deep scratches in the contact area between the 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 lubrication film between the roller end face and the rib. The preload of the sub-bearing is too high. Excessive preload caused by thermal expansion, such as roller inclination 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 (increased viscosity, EP additives, increased lubricant quantity) to ensure the correct adjustment of the bearing.