The BEM Theory And Experiment Research Of Mill Four-Row Conical Bearing

Rolling mill bearings are important part of rolling mill, which work in unconventional situation. In order to fit the requirement of controlled rolling, the heavy reduction is applied and the bowed roll technology is applied to fit the plate shape controls, which make the load of bearing increase dramatically. And the particularity of rolling mill structure limits on the improvement of shaft block structure, which makes service life of bearing descend rapidly, and unusual burning and large area fatigue spalling occur frequently, which restrict the production seriously. Therefore, research of load distribution and service life of mill roller bearing have important meaning for theory and reality.In this paper, according to the fit trait of four-row conical bearing and the reducing dimension of BEM, a special program of computing distribution of bearing load is compiled on Visual Fortran 6.5 Station with language of Fortran 90, which can compute three-dimension pressure distribution, load distribution, contact widths of contact rollers of multi-row bearing, displacement of nodes of body surface, constraint force of nodes on non-contact area and surface stress of nodes under various conditions precisely. Influence laws of different service conditions to load distribution of bearing are analyzed, which provides a powerful theoretical basis to lengthen service life of bearing.First of all, incremental loading method and point to point contact mode are adopted, the multi-body elastic contact boundary element method with friction is proposed. The programs of two-body, three-body and four-body three dimensional elastic contact boundary element method with friction are complied.Secondly, according to the load traits of bearings, a new conception of bearing boundary element is proposed, which realize the discontinuity of surface force of bearing, with which the number of contact rollers can be calculated precisely. According to the different fit modes, four BEM programs of bearing load distribution are complied. The Hertz elastic contact theory is applied to revise the contact widths of roller with inner race and roller with outer race, by which we can get more precise results of load distribution of bearing. Thirdly, the BEM programs of bearing load distribution are used to analyze the four-row conical bearing of duo mill.Experimental duo mill in rolling mill laboratory of Yanshan University is utilized and a special mill roll system is designed and manufactured. The shaft block direct measure method is used to measure load distribution of the four-row conical bearing in static state, dynamic state and rolling state. The experimental data and the result of numerical simulation are compared; the load distribution laws of bearing identify with the test result, which proves the validity and effectiveness of using BEM to solve the load distribution of bearing. According to the data of numerical simulation and experiment, several installation and use reasonable advices of four-row conical bearing are proposed, which lay the foundation of prolonging the service life of bearing.