Remedial measures for rolling bearing fatigue caused by poor lubrication1

Phenomenon (1): Different loads will have different forms of rolling bearing damage under the condition of poor lubrication. When the load is low and there is slippage, fine skin peeling occurs. Because they are numerous and look like pits in the raceway, see Figure 49. We use pitting to describe it. When the load is high and the lubricating oil film becomes thin, such as water intrusion, when the raceway (fig. 29) is subjected to pressure polishing, a shell-shaped dimple appears, see Fig. 50. When the load is high and the lubrication is poor, there will be a very pronounced heated area on the raceway, and after continued operation, initial cracks will appear. Causes: Poor lubrication due to: Insufficient lubricant supply Operating temperature too high Water intrusion causes excessive friction and material stress on raceway surfaces Sometimes there is slip Remedy: Increase lubricant quantity Use high viscosity lubricant and try to Possibly use tested EP additives for cooling lubricants/bearings as much as possible with softer greases to prevent water ingress Fatigue due to wear. Phenomenon (2): For example, there is spalling on the rolling elements of tapered roller bearings, see Figures 51 and 52. Ribbon trace, see Figure 68. Reason: Due to the contamination of the lubricant, such as the entry of foreign particles due to seal failure, the bearing parts are worn in the rolling contact area and the geometry of the parts changes. Part of the result of local overloading is also related to improper adjustment of tapered roller bearings. Remedial measures: Timely replacement of lubricants Filtering of lubricants Improvement of seals Timely replacement of damaged seals Special heat treatment of rings and rollers Fatigue from fracture of the hardened layer. Phenomenon (3): The surface-hardened bearing parts have large pieces of the raceway peeling off. Cause: Cracking or separation of the hardened layer too high or insufficient hardened layer depth for a given load, e.g. due to wrong design load Remedy: Adjust the hardened layer depth to suit the load conditions Avoid overloading Evaluate the operation of the removed bearing Characteristics and Damage Rolling Contact Mode 51: Wear in different areas can change the geometry of the contact area of u200bu200bthe part, so that localized overloading leads to fatigue failure a: cross-sectional profile of the roller; b: inner ring raceway and roller with fatigue damage son. 52: The fatigue mechanism is shown in Figure 51, the edge of the raceway is worn, and the cross-sectional profile of the roller is shown in Figure 69.