| Summary: | 碩士 === 正修科技大學 === 機電工程研究所 === 100 === Gears are the vastly applied important transmission components in cars and various machineries. With regards to different bevel gears, the left and right gears maintain the constant velocity for most parts. Planetary gears were often adopted as equal-arm thrust rod. The gear bearing capacity distribution and strength analysis under the application condition is one of the major research subjects.
This study explored on the effect of gear axial modification on contact stress through the different crowned gear modification value analysis to find the stress spike and stress distribution of its ideal mesh and actual mesh. Furthermore, it underwent gear radial displacement and tangential displacement to explore on the root stress difference of gear working side. Last, a conclusion was derived based from the analysis results proposing a more appropriate modification method and modification value under the design parameters and the analysis on bending stress under different displacement coefficient can serve as reference to the designers.
The analysis results showed that with error-free gear combination, the stress of the contact stress and bending stress is lower compared to after modification because the bearing area is bigger. However, an error-free transmission system is not possible. The errors of the acceptable precision demand causes contact pattern position displacement which would cause change in stress peak value. This study considers the error size of the acceptable precision that occurs under a tolerance of a precision grade of JIS Grade N8 that would cause edge contact. Through a crowned gear modification value of 0.01mm under an edge contact, the stress coefficient increase to 1.708, the stress coefficient would reduce to 1.004 and the appropriate modification value would improve the contact stress peak value by 70%. Therefore, this study has its practicality and value.
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