Research And Design On Ball-cage Type Constant Velocity Joints Of Rolling Mill

Ball-cage type constant velocity joint has been widely used in automobile,steel and other industries because of its constant speed,large swing angle and good bearing capacity.Compared with other types of universal joints relying on the moving spline,the structural of the straight channel in the telescopic ball cage type constant universal joint,transmit torque through meshing with the steel ball,which can move along the axial direction,makes the sliding resistance is smaller and the structure is more compact,proved to be suitable for steel rolling equipment.At present,the analysis and research on ball cage constant velocity universal joint mainly includes the solution of groove contact stress,comparative analysis of groove shape,miniaturization,lightweight and serialization design of universal joint,etc.In this paper,taking the material heat treatment process of the telescopic ball cage type constant velocity universal joint and the analysis of the five major factors affecting the universal joint as the breakthrough point,analysis of the channel contact stress and sub-surface stress depth,put forward the best hardened layer depth and structural parameter optimization design scheme.The thesis mainly includes the following research work:Firstly,based on summarizing the previous research results of the ball cage type constant velocity universal joint,through establishing the geometric model and the kinematics and dynamics analysis of the ball cage type constant velocity universal joint,it is determined that the constant velocity property of the ball cage type constant velocity universal joint is its own structural property,and has nothing to do with its structural parameters.A concrete example is given to illustrate the functional relationship between the normal contact stress of steel ball and the inclination angle of shaft and rotation angle.Secondly,the equations for calculating the contact stress and the long and short axis of the contact ellipse are given by Hertz contact theory.Based on the analysis of the three-direction stress state of channel,the maximum shear stress distance from subsurface depth is calculated theoretically.Thirdly,the meshing contact stress model of star shaped sleeve,bell shell groove and steel ball are established by finite element simulation.The channel is given the material properties of no heat treatment and different surface heat treatment depth,analysis the effect of different hardening layer depth on contact stress and universal joint life.Finally,through the analysis of the elliptic equation of the ball cage type constant velocity universal joint and the groove contact stress formula,enumerate five factors which affecting the structure of the universal joint and the groove contact stress,by using the orthogonal test and range analysis,judge the influencing factors,and optimize the parameter of the main influencing factors.The research process and results of this paper have certain reference significance for the groove surface hardening heat treatment and structural parameter optimization design of cage type constant velocity universal joint.