基于T-Map的飞机部件交点轴线公差转化方法

Tolerance Conversion of Aircraft Component Intersection Axes Based on T-Map

针对装配过程装配方案改变后,基准变换致使几何公差变化的问题,以飞机部件装配中的交点装配为研究对象,提出基于公差图(T-Map)的公差转化方法。根据交点轴线的变动建立交点轴线的T-Map公差模型;通过基准变换前后几何尺寸及公差(GD&T)关系构建交点轴线的基准变换模型,在此基础上,重构基准变换后交点轴线的T-Map;对变换后的交点轴线T-Map进行累积,构建交点轴线叠加T-Map(ST-Map),分析基准变换前T-Map与ST-Map的二维空间域的关系,得到ST-Map最小约束条件,并以不同自由度约束下的最大公差值为判据,获得基于T-Map的交点轴线公差转化关系。最后,引入实例进行公差转化的求解,并与基于特征公差尺寸链的传统公差转化方法进行了比较。

To solve geometric tolerance changes caused by the datum transformations after the assembly processes were changed, a tolerance conversion method was proposed based on T-Map for the intersection axes of aircraft components.The T-Map tolerance models of the intersection axis were established according to the variation of intersection axis.The datum transformation model of the intersection axes were constructed by the geometric dimension and tolerance(GD&T) relationships before and after datum transformation, the T-Map of the intersection axes after the datum transformation was reconstructed based on the datum transformation model.Then, a stacking tolerance-map(ST-Map) was constructed from the transformed T-Map accumulation.The relationship between the two-dimensional spatial domain of ST-Map and T-Map before datum transformation was analyzed to obtain the minimum constraints of ST-Map, and the maximum tolerance value of the constraints with different degrees of freedom was determined to obtain the tolerance conversion relationships based on the intersection axes of T-Map.Finally, an example was introduced to solve the tolerance conversion and compared with the traditional tolerance conversion method based on size chain with feature tolerance.