Fatigue Life Prediction And Application Software Development Of Rotating Tail Hanger Bearings

With the increase of domestic demand for petroleum and natural gas,the performance requirements of low-speed heavy-duty rolling bearings in underground are becoming higher and higher in the process of oil and gas exploitation.Low-speed heavy-duty rolling bearing is an important part of downhole drilling tools.Its fatigue life restricts the working efficiency and service life of downhole drilling tools.Therefore,it is of great significance to calculate the fatigue life of low-speed heavyduty rolling bearing in the shaft simply and accurately,which is of great significance to the structural optimization and practical work of the rolling bearing.In this paper,the low-speed heavy-duty rolling bearing in the underground of a self-developed cementing equipment is taken as an example,and the mechanical properties and fatigue life calculation of the rolling bearing are studied.The main research contents of this paper are as follows:1.Establish a contact stress model suitable for low-speed heavy-duty rolling bearing underground based on the actual working conditions.Firstly,according to the existing non-hertzian contact theory and the actual working condition of the lubricating oil,the lubrication state of the low-speed heavy-duty rolling bearing is verified.Secondly,according to the actual working conditions of low-speed heavy load rolling bearing underground,the reasons why the non-hertz contact theory model and the contact stress model of elastohydrodynamic lubrication are not applicable are analyzed.Finally,the non-hertzian contact stress model is used to optimize and improve the contact stress model of elastohydrodynamic lubrication,and a more suitable comprehensive contact stress model is obtained.2.Based on the improvement of Basquin equation,a new life model is obtained.Firstly,the Basquin equation was optimized by the simple determination method of strain hardening index n,and the improved Basquin equation was obtained.Secondly,the stress amplitude under the actual working condition is obtained by using the comprehensive stress model.Finally,the fatigue life of the low-speed heavy-duty rolling bearing is calculated by using the improved Basquin equation.3.On the basis of existing studies,a vb-based underground low-speed heavy-duty rolling bearing life calculation platform was established,and the feasibility and stability of the platform were verified by examples.After the study in this paper,under the condition that the rolling bearing meets the condition of elastohydrodynamic lubrication,the fatigue life calculation method of the rolling bearing is obtained in this paper,which can be applied to all low-speed and heavy-duty bearings in the underground.