Research On Strength Design Method Of Non-conjugate Point Contact Face Gear Drive

Based on the gear-driven meshing principle,the theory of elastic contact and other basic knowledge,combining the load distribution law of face gear,the bearing ability of face gear is analyzed.This thesis studies and establishes the strength design method of face gear drive and carries out the calculation of face gear strength.Based on the meshing principle and the geometric characteristics of face gear,and the related properties of the surface contact material are considered,the surface elastic contact amount is calculated based on the Hertz elastic contact mechanics,and in turn to get the contact stress formula of the non-conjugate point contact face gear.The discrete points on the tooth surface of the face gear are obtained by solving the nonlinear equation of face gear tooth surface numerically,and these discrete points are imported into the Pro/E software to establish the three-dimensional models of face gear.The dynamic analysis on the established model of face gear meshing transmission is carried out by using the finite element software ANSYS Workbench to obtain the maximum contact stress of face gear drive.Then,the data of the analysis method is compared with the data of the finite element method to judge the correctness of analytical formulas.An analytical model of tooth bending stress of face gear is constructed by parabolicmethod based on the bending stress of cantilever beam.The bending fatigue stress analysis at tooth root of non-conjugated point contact face gear is carried out.The influence factors of tooth width ratio on tooth root bending stress on different cross sections from the big end to the small end in the tooth width direction of face gear are determined.Three-tooth geometric model of point contact face gear is analyzed by finite element method based on the basic theory of finite element.The basic formula of bending stress of face gear is amended to obtain the formula of bending stress at tooth root of face gear including the parameter of tooth width ratio according to the results of finite element analysis.According to the theory of flash temperature and the geometric characteristics of face gear meshing transmission,the computational formula of instantaneous temperature rise of face gear in face gear transmission is deduced.The influence laws of load,rotation speed and the difference of teeth number on instantaneous temperature rise of face gear transmission are analyzed.In order to ensure the anti-gluing strength of face gear transmission,the maximum instantaneous contact temperature of the gear teeth in the whole meshing process is considered to determine the safety factor.Resistance strain measurement method is used to measure the bending fatigue strength of orthogonal face gear drive.In the measurement,several test points are arranged on the tooth root according to the positons where the maximum tooth root bending stress appears.Under the premise of ensuring normal gear meshing,the maximum tooth root bending stress value of face gear is measured based on these test points.Based on the test data,the tooth root bending stress formula of face gear is corrected to get the calculation formula of tooth root bending stress of the non-conjugated point contact face gear closer to engineering practice.