中文摘要：

传统的公差模型以刚体假设为前提,无法考虑机械系统在工作载荷下的变形,而实际工作过程中机械系统性能与各零件在工作载荷下的变形关系密切,为解决此问题,基于新一代产品几何技术规范标准中的认证表面思想提出一种修正公差模型,考虑复杂变形对公差分析的影响,更为真实准确地对系统功能末端的空间位置进行精度预测。采用小位移旋量法和齐次坐标变换法建立传统公差模型;根据认证表面的思想提出拟合配合表面的概念,再根据实际变形表面、拟合配合表面与理想设计表面的空间位置关系,提出修正传统公差模型的方法;给出获取修正矩阵的步骤,建立修正公差模型,进行工作载荷下的公差分析,得到封闭环尺寸的分布规律。以某尾座顶尖为工程对象,证明了该方法的可行性。

英文摘要：

On the premise of the rigid body hypothesis,the traditional tolerance model could not consider mechanical system＇s deformation under working load.Actually the performance of mechanical system had close relationship with parts＇deformation under working load.Based on the idea of certificated surface model of Geometrical Product Specification（GPS）,a modified tolerance model was proposed,which could consider the influence of complex deformation on tolerance analysis and forecast the end space of system function accurately.A traditional tolerance model was built using Small Displacement Torsor（SDT）and Homogeneous Transformation Matrix（HTM）.The concept of fitted matting surface was proposed to consider the part deformation under working condition.According to the space relationship of actual deformed surface,fitted matting surface and ideal design surface,the modified method for traditional tolerance model was proposed.The procedure to obtain the modified matrix was discussed,and the modified model was built.Under the tolerance analysis of working load,the distribution of closed loop dimension was obtained.A tailstock was taken as an example to verify the feasibility of proposed method.