【作者】 陈万群；

【导师】 白清顺；

【作者基本信息】 哈尔滨工业大学 ， 机械制造及其自动化， 2010， 硕士

【摘要】 随着科技的发展当今社会对微小型零件的需求逐渐增加,微小型机床也因其与被加工零件尺寸匹配度好、能耗小、节省空间以及便于装配和运输等诸多优点而深受人们普遍关注,微小型机床的动态特性对加工精度和表面粗糙度有很大的影响,因此对微小型机床进行动态特性分析和结构参数优化对提高加工精度降低表面粗糙度具有重要的意义。首先,对微小型机床的关键部件空气主轴进行了流体动力学分析,对空气主轴气膜压力分布进行仿真模拟得出不同偏心率下的承载力和刚度,并对主轴进行了静力学分析研究主轴在不同切削力下的变形,得出主轴的磨损并非由刚度不足所引起。在上述分析的基础上对空气主轴进行了动力学分析,得出主轴的磨损出现在三阶固有频率附近。其次,运用刚度等效原则建立了微小型机床的有限元模型,对其进行动力学分析,得出床身刚度是整个机床的薄弱环节,并采用了多点锤击单点响应的方法对机床整体和床身进行了动态测试,得出了机床整体及床身的固有频率及其相应的振型,把理论计算结果和实际测试数据进行比较,验证了有限元模型的合理性。最后,在保证床身质量不变的前提下通过对床身进行结构设计和尺寸优化,得到床身的造型和尺寸参数,有效提高了床身的动力学特性。更多还原

【Abstract】 With the technology development,more and more miniature parts were demanded in nowadays, and lots people pay close attention to micro machine tool due to its good size matching with workpiece, low energy consumption, save space, and easy to assemble and transport. The dynamic characteristic of the micro machine has an important influence to the precision and surface roughness. Therefore, dynamic analysis and structural optimization of the micro machine can improve the precision and cut down the surface roughness.Firstly, fluid dynamics analysis carried out on the air spindle obtained the bearing capacity and rigidity under different eccentricity,then static analysis of the air spindle was done, researched the deformation under different cutting force, found the spindle wear not caused by lack of rigidity. At last the dynamic analysis of the air spindle were carried out, and found that the spindle wear occurred in the third-order natural frequency.Secondly, the principle of equivalent stiffness was used to establish the finite element model of the micro machine. After the dynamic analysis, it was found that the airframe was the weak part of the machine. By using the transient powering method and the method of multipoint hammering and single point response, inherent frequency and the corresponding mode of vibration are educed. The theoretical results and actual test data are compared to verify the accuracy of the finite element model.Finally, without changing the weight of the airframe by using the structural design and optimization, improved the dynamics of the machine tool.更多还原