粉末冶金製造技術最大優點在於可大量生產元件，降低製造成本。尤其隨著粉末冶金技術的進步，粉末冶金材料的機械強度表現愈佳，更適合應用傳動齒輪之製造。目前國內對於新製程或新材料所製成的粉末冶金齒輪之疲勞特性尚不明確，同時亦欠缺相關測試之數據，本論文則針對粉末冶金正齒輪齒根強度進行相關研究。 在本論文中，粉末冶金齒輪齒根應力是根據ISO 6336-3方法B來計算，並輔以有限元素分析進行驗證。為建立齒輪齒根疲勞強度標準實驗程序，本論文先進行測試治具之設計，並驗證此型式之設計在加工、組裝誤差對齒輪負載位置精度的敏感度甚低。實驗測試齒輪之材料使用常用之Fe-1.75Ni-0.5Mo-1.5Cu-0.4C燒結合金鋼(相當於MPIF FD-0205)，以振動測試的方式，在MTS疲勞試驗機進行齒輪的齒根疲勞測試。測試結果則應用韋伯分布函數來推估不同可靠度下齒根強度值，並據以建立疲勞曲線圖。 Powder metallurgy (PM) technology has the advantages in mass production of components and thus reduced manufacturing cost. Recently, the mechanical behavior of PM materials is getting better because of improvements in PM technology, so PM materials are suitable for application in gear transmission. However the design information on fatigue properties and strength data of PM gears made by new manufacturing processes or new materials are not sufficient for the domestic manufacturers. The aim of this thesis is to study the tooth root strength of PM spur gear. The tooth root stress of PM gear is calculated according to ISO6336-3 method B and verified by the finite element method. In order to set up the standard test procedure, a test fixture was designed and verified that the sensitivity to deviated root stress due to assembly errors or machining errors of the test fixture is low. The test gears were made of sintered steel (Fe-1.75Ni-0.5Mo-1.5Cu-0.4C). The fatigue test was conducted on a MTS test machine by the pulsing method. A S-N curve of the test material was established by using the fatigue test data according to Weibull distribution for the failure probability.
