Static Characteristics Analysis Of Tapered Roller Bearing-spindle System

Tapered roller bearing-spindle system is a common structure in mechanical transmission,mainly used in high-speed machine tools,aviation engines,high speed rail and automobile engines and other fields.When the spindle system is loaded,the deformation of the shaft and the bearing layout will affect the contact stress distribution of the bearing,which is significantly different from the mechanical characteristics of individual bearings.Therefore,when designing and calculating spindle systems,it is important to consider the interaction and coupling effects between bearings and shafts to improve the accuracy and stability of tapered roller bearing-spindle systems.The main research contents and conclusions of this thesis are:（1）Based on the Hertz line contact theory,the numerical solution of a single tapered roller is carried out to optimize the convexity of the roller by comparing three different ways of trimming the curve for the edge effect of the roller.The H-T logarithmic profile with different control parameters is used to optimize the convexity of the rollers of 30206 bearing,and the best control parameter is obtained when the curvature synthesis coefficient is k₁=1.5and the convexity z_mis 6μm,which can solve the stress concentration phenomenon of tapered roller well.（2）Taking 30206 tapered roller bearing as an example,an overall static model of the bearing considering all roller contact characteristics is established,and the influence of the load in each direction on the roller force is analyzed.When the bearing is subjected to axial and radial forces only,most of the rollers are loaded and subjected to uniform forces,except for the top roller.When there is an overturning moment in the load,the tapered roller tilts,resulting in uneven contact stress on the roller.The H-T curve shaping can effectively reduce the contact stress at the edge of the roller.（3）The local coordinate system of tapered roller bearing in space is established,and the six-degree-of-freedom stiffness matrix of the bearing is derived by analyzing the relationship between displacement and load of the tapered roller bearing.Specifically,the axial stiffness and radial stiffness of the 30206 type bearing were calculated,and the deviation of the stiffness values were within 5%after comparing the calculated results with those of KISSsoft software.（4）A static analysis model of tapered roller bearing-spindle system considering spindle deformation was established.The stiffness matrix of the system was formed by coupling the stiffness of the shaft section unit and the tapered roller bearing unit,and the forces on the bearing,the load distribution of the bearing and the deformation of the shaft under the support conditions of the simply supported beam and cantilever beam were analyzed and calculated,and the difference between face-to-face and back-to-back mounting of the bearing was compared.By comparing with the simplified finite element model,it was found that the elastic deformation of the bearing could not be neglected.By comparing with KISSsoft results,it is found that the error of bearing load size is only about 2%,The trend of main axis displacement results is basically the same,and the maximum error of angular displacement size is about 0.5e^-6mrad.