自動平衡裝置之暫態碰撞行為分析

Abstract

滾珠型自動平衡裝置具有在高於系統自然振頻的大範圍轉速下平衡振動的能力，因此在不定負荷的旋轉機械中已有廣泛的應用，然而仍一直有性能表現一致性不佳的缺點。本研究以探討雙滾珠自動平衡裝置之暫態行為特性為目標，藉由赫茲接觸理論與有限元素法所建構之接觸參數模型，來建立滾珠與滾珠之間、滾珠與軌道之間的接觸關係；並經由改變滾珠初始位置所得的暫態模擬結果，來計算系統收斂時間及最大振幅之變異情況，以觀察系統性能表現的一致程度。再經由特性參數之敏感度分析，顯示等效定子質量及軌道黏滯液阻尼係數對系統收斂時間的影響較大，系統等效阻尼係數及等效定子質量則對最大振幅有較大的影響，而碰撞次數的最大影響參數則為軌道黏滯液阻尼係數，其結果期望能提供設計工程師在設定系統參數數值及改良時的參考。

Being capable of balancing vibration at speeds higher than the natural frequency, automatic ball balancers have been widely used in rotary machinery with uncertain imbalance. However, it suffers from inconsistent performance in real operations. The purpose of this research is to analyze transient contact behaviors of two-ball balancers. Using Hertz contact theory and finite element analysis, contact models are established for collisions between balls and those between balls and the race. Consistency of system performance is investigated by observing the variation of convergent time and the largest vibration amplitude by transient simulation under changing initial conditions of balls. Based on the results, the effects of system parameters on transient behaviors are realized. It is found that mass of the stator and race damping have significant influence on convergent time, whereas system damping and mass of the stator have strong effect on the largest amplitude of system vibration. Changing race damping are influential on the number of collision. The results are expected to facilitate the settings of system parameters design improvement.