The performance of rolling bearings has a major impact on the performance of mechanical systems. However, there are many factors affecting the fatigue life of rolling bearings, such as working temperature, impact load, reliability, materials, operating conditions, limit speed, surface roughness, inclusions, indentation, lubrication. State, radial clearance, deflection, fatigue crack induced stress, tangential friction, residual stress and hoop stress, surface treatment, etc. These factors affect each other, combined with the non-repetition of fatigue life test, the influencing factors are still difficult to be accurate Quantitative description.
Rolling bearing fatigue life The classic L-P theory is based on the assumption that the fatigue failure of a rolling contact originates from the depth at which the orthogonal shear stress is greatest at the contact area. However, with the development of the bearing manufacturing process, the fatigue failure mode originating from the surface appears more frequently than the subsurface fatigue failure mode. There are three mechanisms for crack initiation: crack initiation from the surface, crack initiation from the near surface, and crack initiation in the material matrix.
The puncture life originating from the surface and the spalling life of the subsurface origin are competing failure modes, which are predicted as a function of the film thickness ratio, the root mean square value of the slope of the rough peak, and the traction coefficient in the rough contact of the boundary lubrication.
With the development of high-speed railway and aviation industry, there are more and more requirements for high reliability of bearings, and the temperature of bearing application environment changes greatly. It is necessary to study the coupling between reliability and temperature. Rolling bearing materials are still in development. It is necessary to explore the relationship between the surface integrity of the parts and the surface fatigue pitting. On the microscopic scale, the effects of surface integrity and lubrication effects on the fatigue pitting point are revealed. On the other hand, combined with the load characteristics and the dynamic response of the material to study the spalling failure, analyze the dynamic response of the bearing material to the external load, study the coupling relationship between fatigue performance and material properties, and obtain the relationship between the dynamic response of the material and the surface fatigue spalling.
For other factors affecting bearing fatigue life, such as lubricants and additives, surface roughness, hoop stress and interfacial slip, etc., comprehensive research is also needed, such as the establishment of databases and R&D software packages for automated analysis of lubricants and bearing materials. With choice, this is also one of the future directions.
Analysis of the factors affecting the rolling failure of the bearing helps to better understand the mechanism of bearing fatigue failure. On the one hand, it can avoid the factors that reduce the bearing life and improve the fatigue life of the bearing; on the other hand, it can provide some guidance for the development of fatigue life theory, in order to improve the accuracy of bearing fatigue life prediction.
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