Generating Precision Parametric Model Of Involute X-gear And Analyzing The Bending Strength

Using the Computer Aided Design and Computer Aided Analysis, a parametric model of involute cylindrical spur gear with addendum modification was generated accurately, then the bending strength of gear tooth was analyzed. Because of taking advantage of low cost, high efficiency, high precision of numeric technology, the accuracy of bending strength analysis was enhanced greatly. This thesis contains twoparts:1) Generate the precision parametric model of x-gear. According to the principle of generating process, the parameter equations of involute curve and transient curve were established, considering the possibility of addendum modification. The 3D parametric model of x-gear based on these two equations is competitive accurate, through the error testing of geometry model.2) Fix on the inner connection of addendum modification coefficient and bending strength. With the application of FEM(Finite Element Method), the static analysis of precision model was made, and a practical calculating formula was followed to be regressed from the modification coefficient and the bending strength according to the Similarity Theory. On the condition of knowing the root stress value of x-zero gear, the bending strength of x-gears with the same teeth can be calculated through the formula.On contrast of the result of photoelasticity test, the value obtained from FEM indicated that: the outcome of precision model, which is close to the result of photoelasticity test, is more accurate than the outcome of the model with arc instead of transient curve. Also the value calculated from the formula is close to the result of photoelasticity test, and more accurate than the result of other traditional method.