應用吸振器抑制旋轉軸偏心振動技術之研發

Vibration Suppression of Unbalanced Spindle Using Absorber

何育賢(Ho Yu Hsien)

指導教授 ： 鄭志鈞

國立中正大學/工學院/機械工程學系/碩士(2013年)

摘要

本研究之目的是基於吸振器理論，設計一旋轉式吸振器，使其隨旋轉軸旋轉，符合旋轉軸之頻率與所要抑制之模態，便能自動追蹤旋轉機械之偏心位置，並抑制因主軸質量不均或組裝誤差，所產生徑向、扭轉或彎曲振動，具不須外接電源、安裝方便、成本低廉之優點。
橡膠式吸振器因阻尼過大，導致其模態不易被激發，也因阻尼效應使得吸振效果不彰，因此，不考慮阻尼值大之組件，僅基於質量彈簧系統設計，研發第一、二代彈簧式吸振器，兩代設計之主要組件皆包含螺旋壓縮彈簧、質量圓環，以及圓桿構型之樑。
模態實驗結果顯示第一代吸振器系統不強健，為一可變結構，導致所激發之模態不穩定，也使得主軸振動量不減反增，因此，經改良後研發第二代吸振器，實驗結果清楚顯示其第一自然頻率，以及系統強健之特性，調整簡諧型式(正弦波)之外力頻率和第一自然頻率相同或相近，並於高速攝影下觀察發現，吸振器於該頻率下所對應之模態為徑向模態，然而，主軸抑振實驗結果顯示，兩代吸振器未如預期的有效，反而使得主軸振動量加劇。然而，另一基於呼拉圈動態所研發之減振裝置，實驗結果顯示其能降低逾70%振動量。目前推測造成吸振器無法發揮效果，其主要原因為吸振器其自身旋轉，即吸振器和主軸同步旋轉將使得吸振器無法基於一質量彈簧系統作動，未來研究方向也許應排除自身旋轉效應，若主軸軸向為Z方向，徑向為X、Y，則吸振器應僅剩X、Y方向之自由度，而無繞轉Z方向之旋轉自由度。

關鍵字

吸振器

並列摘要

A novel design of a vibration absorber used in reducing the vibration caused by the imbalance of spindle in a rotating machinery is proposed. The proposed vibration absorber consists of helix springs and a ring. The absorber is installed on a spindle and rotates with the spindle. The objective is to make the first radial natural frequency of the absorber coincide with the rotating speed of the spindle. From a theoretical approach, it shows that the absorber can effectively suppress the vibration in the radial direction caused by the imbalance of the spindle and acts as an auto-balancer. Modal testing of the proposed absorber was performed to determine its first radial natural frequency; and the mode shape is captured using camera. Experimental results show that the first mode of the absorber is a radial mode. When the absorber is installed on a shaft and rotates with the shaft; however, it tends to move to one side of the rotating shaft and remains stationary. However, the vibration absorber in suppressing the vibration caused by the rotating imbalance is not effective as expected. Nevertheless, another device which is designed based on Hula-hoop dynamics in reducing the vibration due to imbalance is proposed. Experiment results show that the vibration caused by imbalance can be reduced more than 70%. Further study to investigate the reason why the proposed absorber fails in reducing the imbalance vibration and the mechanism that induces the hula-hoop to suppress the imbalance vibration as well will be addressed in the future.

並列關鍵字

Absorber

參考文獻

[8] 呂程祥，2012，“呼拉圈能量獵取裝置之設計與動態分析”，國立清華大學動力機械工程研究所博士論文。(宋震國)

stability in boring operations with passive vibration absorbers,” International Journal of Mechanical

Engineering Science, 45, pp. 562-586.

[13] S. T. Wu and Y. J. Shao, 2007, “Adaptive Vibration Control Using a Virtual-Vibration-Absorber

[14] S. J. Jang and Y. J. Choi, 2007, “Geometrical Design Method of Multi-Degree-of-Freedom Dynamic