拖拉机变速箱体定位销孔凸缘裂纹分析

Crack analysis of pinhole rib of the tractor gearbox

对拖拉机变速箱体定位销孔的凸缘曲线进行了分析，建立了凸缘过渡曲线数学模型，改进了定位销孔的凸缘曲线和夹具定位销结构。分析和应用结果表明，造成销孔凸缘裂纹的原因是制造过程中定位误差等引起的冲击力、销孔的凸缘曲线结构不合理及应力三个因素引起的。改进后变速箱体销孔凸缘曲线不再产生裂纹现象。

Based on the analysis of the crack of pinhole rib of the tractor gearbox, the mathematical model has been built for curves of pinhole rib and the curves has been improved in this paper. We have also improved the structure of pin in fixture. The result of the analysis and application show that the crack of pinhole rib is caused by the impact produced by fix error, the unreasonable structure of pinhole rib and internal stress. After improved, the pinhole rib of gearbox has no longer produced crack.