等值原则及其在圆度误差评定中的应用研究

Constant Value Principle and Its Applications in the Evaluation of Roundness Tolerance

坐标测量机和计算机技术的发展 ,在公差检测、描述以及数学定义等方面都提出了新的挑战。文章尝试性地提出了基于材料力学中固体连续性假设的等值原则 ,阐述了按等值原则确定实际要素的理想形状要素 ,在该理想形状要素的基础上 ,进行相似胀缩来形成便于计算机描述的公差带 ,通过坐标轴平移和旋转来完成公差带的精确数学描述 ,从而实现尺寸公差、形状公差和位置公差等统一的思想。最后 ,在圆度误差评定中进行了应用举例 。

The developments of coordinate measurement machine (CMM) and computer technology have raised new challenges in measurement, description and mathematical definition etc. of tolerance. This paper attempted to put forward the constant value principle based on the hypothesis of continuity of solid body in mechanics of materials; and stated the method of realizing the unity of dimensional tolerance, form tolerance and position tolerance etc. Through obtaining the ideal form feature of actual feature in the light of the constant value principle, and getting the tolerance zone which is convenient for its computer description based on the similar sweel shrink of ideal form feature, as well as achieving the correct mathematical description of the tolerance zone through the translation and rotation of coordinate axis. At last, some valuable conclusions in use are obtained in the evaluation of roundness tolerance according to them.