| For gear transmission, there are the advantages of accurate transmission ratio, high transmission power, strong carrying capacity, long service life, high reliability and etc, it is the most widely used mechanism in mechanical transmission. With the progress of technology, gear transmission is toward miniaturization, high power density, standardization direction to develop, requirement of higher load capacity is put forward. The bending fatigue strength which determines the service life of gear is an important index to evaluate the load capacity, it is necessary to study the fatigue behavior influencing factors of the gear and to accumulate the basic data. In this thesis, the bending fatigue strength of 18CrNiMo7-6 gear material and the fatigue characteristics of the meshing gears are studied by using the test method and the finite element analysis method. The main research contents are as follows:(1) Based on routine grouping method, gear bending fatigue experiment is carried out on the high-frequency fatigue testing machine. Parameters in the calculation formulas of tooth root bending stress are derived by 30°tangent method.(2) By mathematical statistics theory, the data of the fatigue life are dealt with, and that the gear fatigue life obeys the logarithmic normal distribution is determined. In order to obtain the bending fatigue limit of gear under different reliability, the R-S-N curve is fitted by using the least squares.(3) By ANSYS Workbench, the stress change with time during gear meshing process is obtained through transient dynamics analysis and load data for fatigue life simulation are provided.(4) Based on the nominal stress fatigue analysis method, by a virtual fatigue analysis software nCode DesignLife, the fatigue life distribution contours at the weakest position of the gear are obtained. By comparing the simulation data with the experimental data, the simulation analysis for gear fatigue property is worthy of being studied. |
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