Research On Accelerated Life Prediction And Wear Failure Mechanism Of Rolling Function Components

Fatigue life is an important performance indicator of rolling components.Compared with foreign products,there is a large gap about the fatigue life and reliability of domestic rolling components.Therefore,the fatigue life,the rated dynamic load,the fatigue failure were modeled and predicted,tested and amended,studied and analysed respectively based on the test data.It is of great significance for the test research and the level of national modernization.In this paper,the elastic-plastic analysis of rolling components was studied to determine the stress range of the accelerated life test.Based on the self-developed rolling test bench,combined with the sub-step accelerated test method and the screw A+A accelerated reliability testing method,The method of accelerated test was developed and carried out respectively.Relevant test data and fatigue failure samples were obtained.Based on the test data,Weibull distribution was established and the reliability of the life about rolling components was analyzed,and the life model was established and improved,reducing the fitting error and detemining the acceleration factor and the life stress index.The life of the rolling components under normal working conditions was predicted.On the basis of summarizing the insufficiency of the formula about the rated life and dynamic load at the present stage,the test program of the rated dynamic load was developed based on the accelerated life test technology.With the test data and life model,The calculation formula about the rated life and dynamic load was revised.Combined with the test and fatigue failure samples,the failure mechanism and failure evolution mechanism of rolling components were studied.The results shown that fatigue failure of the guide rail mainly occured at the boundary of the raceway and the deflector,failure of the ball screw mainly occured at screw raceway.The indentation was easy to occur on the raceway surface with low hardness and the surface roughness could effectively characterize the fatigue failure process.The initiation and expansion of surface and subsurface cracks led to fatigue failure,and joint fatigue failure would eventually lead to fatigue spalling.Residual compressive stress could effectively reduce fatigue failure and increased with the running.