臺灣博碩士論文加值系統

一般軸承在潤滑狀況下若有軸電流通過，常會發生電弧，使軸承表面產生電蝕現象，而縮短其使用壽命。放電所產生之電蝕和軸電壓、潤滑油膜厚度及潤滑油之絕緣性有密切關係。為實際模擬電蝕形成之機制，因此研發動態電蝕試驗機，針對常用之軸承材料，藉改變供應電壓、電流及油膜厚度等，探討在運動參數下對電蝕形成機制之影響。
實驗結果發現，在靜態電蝕情況下，由於電弧作用使兩試片表面熔融，加上庫倫力與靜電力作用會使試片產生相互吸引，使試片表面凸起有如架橋般連接，此時材料仍不斷累積，導致兩試片會有互相擠壓之力量產生。而動態電蝕情況下，電蝕形成初期與靜態相似，會有架橋及相互擠壓之力量的現象。加上滑動速度的影響，使架橋剪斷而導致有摩擦力的產生。且在焦耳熱及摩擦力持續作用下，使兩試片表面不斷地熔融及刮擦。
當動態電蝕發生時，方塊試片之電蝕寬度及兩試片間所產生之正向力與摩擦力隨供應電壓、電流及油膜厚度增加而變大。當界面功率愈大時，試片表面所產生之熔融現象更加明顯，造成電蝕寬度變大。也因熔融現象更加明顯加上庫倫力與靜電力的影響，使材料累積愈快速，造成正向力及摩擦力愈大。綜合所有實驗參數對電蝕寬度之影響建立一經驗公式針對旋轉機械在供應電壓及電流的作用下，預測油膜厚度或觀察軸承表面電蝕寬度之大小，診斷軸承之潤滑狀況。

When the shaft current passes through the bearing under lubrication condition, the arc often occurs and the pitting can be observed on the surface of bearing. Consequently, the life of bearing is shortened. The pitting resulting from discharge is dependent upon the shaft voltage, the oil film thickness, and the insulation of lubricant. To simulate the pitting, the dynamic pitting tester is developed to investigate the effects of the kinematics parameters on the electrical pitting formation mechanism for the common material of bearing by changing the supply voltage current and the oil film thickness.

Result show that in the static condition, since the arc action causes the surface melting of two specimens, and the actions of coulomb force and electrostatic force cause the specimens to attract each other, the plateau can be observed on the surfaces of specimens. The plateau is like a bridge to connect two specimens. In this moment the plateau accumulates continuously and causes two specimens to produce the repulsive force. In the dynamic condition, the formation of pitting at the initial stage is quite similar to that in the static condition. Since the effect of sliding speed, the bridge is sheared and the friction force increases. Under the actions of joule heat and friction force, the surfaces of two specimens melt and scratch continuously.

When the dynamic pitting occurs, the pitting width of square specimen, the normal force and the friction force increases with increasing supply voltage, supply current, and oil film thickness. When the interface power is larger, the melting phenomenon is more obvious, and the pitting width becomes larger. Because the surface melting and the actions of Coulomb force and electrostatic force cause the material accumulates continuously, the normal force and the friction force increase with increasing the interface power. To investigate all effects of experimental parameters on the pitting width, the empirical formula for the pitting width is established in terms of supply voltage, supply current, and oil film thickness. This formula can be used to predict oil film thickness or the size of pitting width on the bearing surface for diagnosing the lubricant condition of bearing.

封面 Ⅰ
授權書 Ⅱ
論文口試審定書 Ⅲ
謝誌 Ⅳ
目錄 Ⅴ
圖目錄 Ⅷ
表目錄 ⅩⅥ
中文摘要 ⅩⅦ
英文摘要 ⅩⅧ
符號說明 ⅩⅩ
第一章 緒論 1
1-1 研究動機 1
1-2 軸電壓與軸電流之來源 2
1-3 放電現象之發生與種類 6
1-4 文獻回顧 8
1-4-1 軸電壓、軸電流形成之原因 8
1-4-2 軸電流對軸承電蝕損傷之影響 9
1-4-3 電蝕機制之探討 10
第二章 實驗設備與方法 12
2-1 實驗設備 12
2-1-1 動態電蝕試驗機系統 12
2-1-2 量測與資料收集分析系統 15
2-1-3 滑動及油膜厚度控制系統 16
2-2 實驗材料及潤滑油性質 18
2-2-1 鋼材配對之尺寸及材料特性 18
2-2-2 試片處理 20
2-2-3 試片平行度校正 22
2-2-4 潤滑油 23
2-3 實驗條件 23
2-4 實驗步驟 25
2-4-1 試片間接觸區與非接觸判斷 25
2-4-2 油膜厚度之調整 25
2-4-3 電蝕試驗之實驗步驟 28
第三章 實驗結果與討論 31
3-1 電弧特性觀察 33
3-1-1 界面電壓與界面阻抗 33
3-1-2 界面功率 51
3-2 電蝕之觀察 68
3-2-1 靜態電蝕形成機制 68
3-2-2 動態電蝕形成機制 74
3-3 實驗參數對電蝕之影響 78
3-3-1 電流效應對電蝕之影響 78
3-3-2 電壓效應對電蝕之影響 83
3-3-3 滑動速度對電蝕形態之影響 87
3-3-4 油膜厚度對電蝕形態之影響 91
3-4 實驗參數對電蝕寬度之影響 96
第四章 結論 101
參考文獻 103

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