以單轉子模式分析高速主軸系統特性與氣浮軸承參數之鑑別研究

The Investigation of System Characteristics and Identification of Air Bearing Parameters for a High Speed Spindle Modeled with a Single-Rotor System

邱昭智(Chao-Chih Chiou)

指導教授 ： 陳 永 樹

元智大學/工程學院/機械工程學系/碩士(2003年)

摘要

高速氣浮主軸系統已被運用在高科技電子產業機械之主軸上，如PCB鑽孔
機、晶圓切割機等高精密主軸領域。在產業已進入奈米科技的時代，相對
於氣浮主軸性能要求也不斷往上提升。因此本文是以實驗方式結合有限元
素分析，探討氣浮主軸系統統動態特性與系統參數鑑別。包含以珠擊實驗
法鑑別出含止推軸承與未含止推軸承氣體軸承剛性與阻尼參數。以模態實
驗法分析主軸系統心軸在Free-Free、水平置放含止推軸承、水平置放未
含止推軸承之模態特性與差異，以了解系統之動態特性與軸承邊界效應之
影響。
以珠擊實驗法鑑別軸承剛性結果指出，在受徑向軸承作用時加入止推軸承
作用所得之軸承剛性比未加入止推軸承作用時剛性值高，主因是心軸圓盤
受止推軸承包覆作用下，對心軸產生懸浮作用所致。且增加軸承懸浮氣體
壓力剛性值隨之提升。而在相同的軸承懸浮壓力下，以不同質量之鋼珠進
行實驗，對於系統之剛性並沒有顯著的影響。
經由頻率響應試驗，量得在頻寬20kHz內心軸本身的四個結構模態頻率，
且由FEA分析驗證此四個模態之頻率與振型，藉以確認所用材料參數之正
確性，同時亦得知此四模態都在高於一般主軸系統之轉速頻率。隨後應用
此驗證過之參數，於後續之主軸模組在實際充氣狀態下的分析，並且與實
驗結果再做比對。由實驗量得之頻率響應曲線中，得知在2kHz以內受氣體
軸承作用下，可測得峰值不是很顯著之模態頻率。但經由FEA分析模型，
代入珠擊實驗法所得之剛性與阻尼參數後，驗證出受氣體軸作用後所產生
之四個模態頻率且其值與實驗甚為接近，而振型都為圓錐振型。此四個模
態頻率皆在工作轉速範圍內，因此對於系統將會有實質上的影響。經由本
研究所得之剛性與阻尼參數，將可作為主軸分析設計時之參數設定的依
據，對於主軸系統特性之掌握，將是極為重要的資訊。

關鍵字

頻率響應函數 ； 珠擊實驗法 ； 氣浮主軸系統 ； 止推軸承 ； 剛性 ； 阻尼

並列摘要

The high speed air spindle system has been used popularly in
some of the manufacturing machines in electronics industry.
Such as those applications in the printed circuit board
drilling and wafer saw cutting machines…etc. The study
investigates the dynamic characteristics and identifies some of
the parameters for the air spindle system by using both the
experimental and finite element analysis (FEA) methods. It
includes measuring the air bearing stiffness and damping for
both cases of with thrust bearing and without thrust bearing.
Also, the tests conducted including the spindle placed
horizontally in the free-free boundary conditions, and the case
where the spindle is supported by the pressurized air when with
and without the thrust bearings respectively. The testing is
aimed to study the influence of dynamic characteristics and
boundary conditions on the air spindle system.
The results of the steel ball impact testing for the
identification of the bearing stiffness show that the stiffness
in radial direction increases for the case with thrust bearing
when compare with the case without thrust bearing. Moreover,
increasing air pressure will also increase radial stiffness.
There’s no observed difference for the stiffness measured with
steel balls of different weights in the impact test.
From the frequency response function(FRF) measurement for the
spindle mandrel itself, it shows that under 20kHz bandwidth,
there are four natural frequencies exist when at free boundary
conditions. These data are verified further in FEA by adjusting
the material constants in the model. These verified material
constants together with the measured data of the spring and
stiffness constants from ball impact test, are employed later
for the analysis in the real case of air bearing supported
spindle. The first four frequencies of the real case are not
very clear in the FRF test. However, they are checked again in
the FEA model. It is found that the results from both of them
are very close each other and all are located within the
working frequencies of the spindle system. Hence, these
frequencies will have key effects in the performance of the
spindle system. It is believed that the dynamic
characteristics, stiffness and damping obtained in the study
will contribute as a critical reference for the high spindle
system design.

並列關鍵字

FRF ； ball impact testing ； air spindle system ； thrust bearing ； stiffness ； damping

參考文獻

Externally Pressurized Air-bearing Pads, ” Tribology

1990.

[13] Ewins, D. J., “Modal testing: Theory and Practice, ”

Analysis Theory and Testing, ”Katholieke Universiteit

Leuven, Belgium, 1997.