高精度内圆磨床整机集成优化设计研究

机床结构动态优化设计是提高机床加工精度的关键。本文建立发内圆磨床整机有限元模型，分析了原磨床在结构上的缺陷；修正了主要结构部件的模态频率，使其模态频率分离，避免了部件集成整机时由于整机的激励频率接近部件模态频率出现整机振幅增大现象。以整机第一阶模态下磨头与工件之间振动模态相对位移值作为整机动态性能的评价指标，采用模态力法找出机床结构的薄弱环节，并对其进行优化。优化后的磨床与原型相比，第一阶固有频率提高17％，对应的磨头与工件振动模态相对位移量降低10％，磨头处的响应位移量在第一、二阶频率处下降28％和41％，实现了磨床的动态优化。

A STUDY ON INTEGRATED OPTIMAL DESIGN FOR A HIGH-PRECISION INTERNAL GRINDER

Dynamic optimization design is the key to improve the machining precision of machine tools. The structural deficiencies of the internal grinder was pointed out by analyzing its FE model. A method of frequency correction was proposed, by which the mold frequencies of the main parts of the internal grinder were disclosed, and increase in vibration of the internal grinder avoided when the prompting frequency of the internal grinder comes close to its nature frequency. In addition, the value of relative vibration between the cutting tool and work piece in its first natural frequency was considered as a standard of estimation of the machining precision for internal grinders, the model force method was applied to seek the structural weakness of the internal grinder in order to achieve dynamic optimization of the parts. The results of both methods applied in the integrated optimal design of the internal grinder show that the first stage natural frequency of the re designed internal grinder is increased 17% compared with the original, the vibration mode relative displacement between the head of grinder and work piece is reduced 10%, and the response displacements of the first and second stage natural frequency in the head of the grinder is reduced 28% and 41%.