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Developmental Research of Hydrostatic Air Spindle for Ultra-Precision Machine Tools

超精密机床静压气主轴的开发研究

基本信息

批准号：
06555044
负责人：
ONO Kyosuke
金额：
$ 9.79万
依托单位：
Tokyo Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Developmental Scientific Research (B)
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1995
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-06555044/
关键词：
Hydrostatic Air Bearing Ultra-Precision Machine Tools Maximum Dynamic Stiffness High Damping Design Circumferential Grooves Lattice Grooves Random Force Excitation RMS Value of Response ランダム外乱力変位反応回転精度高減衰空気軸受静圧エアスピンドル格子形溝軸受面

项目摘要

1) Development of the maximized damping design at resonance frequency of bearing-rotor system : Based on the frequency characterisitics of squeeze film damping, we established a design method of maximizing air film damping at resonance frequency of the bearing-rotor system by fabricating the lattice grooves on the radial and thrust bearing surfaces. From this design concept we can increase the damping ratio at resonance up to more than 0.1.2) Vibration analysis of hydrostatic air spindle including elastic deformation of rotor : Based on the finite element method, we developed the structural modal analysis program of the bearing-rotor system including the elastic deformation of rotor and the equivalent stiffness of the connecting bolts. As a result it is found that not only the three stractural natural frequencies of rotor up to 11 kHz but also air bearing resonances can be predicted more accurately within 5% errors.3) Development o air spindle design method of minimizing the rms value … More of rotor response caused by the machining force with various kinds of frequency spectrum : We first determined the radial and thrust bearing configurations so as for the static displacement at machining point to be minimized. Next we developed a design method of compromizing the static stiffness and resonance damping ratio in order to minimize the rms value of dynamic response at machining point. The optimal air bearing designs for narrow and wide band spectrum external forces are exemplified. Further the lowest bending vibration frequency of rotor can be increased up to 7kHz.4) Realization of ultra-precision air spindle with 10nm/N dynamic compliance in terms of 3 sigma : We made an air spindle prototype whose rms value of the dynamic response is minimized to the imposed machining force with uniform amplitude for the frequencies from 0.5 to 5 kHz. From measurement of the bearing characterisitics, it is found that, because of the machining inaccuracy, the effective bearing clearance is 4 to 4.5 mum, so that the static stiffness is 50 to 70% of the theoretical value for 5 mum nominal clearance. The dynamic air film stiffnesses are larger than the calculated ones by 20 to 30% and the damping ratios are 60 to 80% of the calculated ones. However, it is confirmed that the 3 sigma value of the dynamic compliance of the spindle supported freely can be within 10nm/N in both the radial and thrust directions. It is also found that the rms value of nonrepeatable vibration is less than 10 nm. Less

1)轴承-转子系统共振频率处最大阻尼设计的研究：基于挤压油膜阻尼的频率特性，建立了通过在径向和推力轴承表面加工网格槽，使轴承-转子系统共振频率处气膜阻尼最大的设计方法。2）考虑转子弹性变形的静压空气主轴振动分析：基于有限元法，开发了考虑转子弹性变形和连接螺栓等效刚度的静压空气主轴轴承-转子系统结构模态分析程序。结果发现，不仅可以更准确地预测转子的三个结构固有频率（高达11 kHz），而且可以更准确地预测空气轴承共振，误差在5%以内。3）最小化均方根值的空气主轴设计方法的开发 ...更多信息不同频谱的加工力对转子响应的影响：首先确定径向轴承和推力轴承的结构，使加工点的静态位移最小。其次，我们发展了一种平衡静态刚度和共振阻尼比的设计方法，以最小化加工点处动态响应的均方根值。举例说明了窄谱和宽谱外力作用下空气轴承的优化设计。4）实现3 σ动态柔度为10 nm/N的超精密空气主轴：我们制作了一个空气主轴样机，其动态响应的均方根值最小化，在0.5到5 kHz的频率范围内具有均匀的振幅。从轴承特性的测量中发现，由于加工误差，有效轴承间隙为4至4.5 μ m，因此对于5 μ m标称间隙，静态刚度为理论值的50%至70%。动态气膜刚度比计算值大20 ~ 30%，阻尼比为计算值的60 ~ 80%。然而，它被证实，自由支撑的主轴的动态柔度的3 σ值可以在径向和推力方向上都在10 nm/N以内。实验还发现非重复振动的均方根值小于10 nm。少