本文之目標在於探討如何利用有限元素法對齒輪減速機箱體結構進行適切的模擬分析，以預估箱體應力應變型態進而提供設計改良參考。
箱體結構本身形體複雜，在分析時需要做些簡化與假設以利電腦模擬的執行。首先以不含齒輪、傳動軸及軸承的齒輪減速機箱體來建立有限元素三維模型。只考慮靜態負荷。以靜力分析的方式將齒輪負荷分配到各軸承座，作為箱體模型的外力負荷，利用有限元素法模擬出箱體的應力應變分佈。同時對減速機箱體黏貼應變規進行實驗量測，以驗證電腦模擬的可靠度。
由於模擬與實驗兩者的結果比較後發現差距極大，考慮將傳動軸加入分析模型中作為分析修正，但模擬後卻發現結果相差更遠。探究原因為忽略了軸、軸承、箱體三者間的接觸效應，導致在接觸區的負荷情形產生偏差。
為了瞭解接觸效應對模擬的影響性，先對減速機中各軸局部進行簡單的二維接觸模式分析，由結果瞭解到接觸效應的特性以及先前模擬所存在的一些缺失。重新建立包含減速機箱體、傳動軸與軸承的有限元素三維接觸模型。同樣為靜態模擬，但此時的外力負荷則是以齒輪對傳動軸所造成的等效作用力為考量。
再次將模擬與實驗的結果做比較，發現大幅降低了兩者間的差距。所以三維接觸分析雖然複雜，但能有效改善模擬適切性，是較好的模擬分析方式。

The goal of this thesis is to set up a proper finite element model to simulate the gear reducer box. From the results of finite element simulation, we can estimate the state of stress and strain of the gear box and modify the design of the gear box.

Since the geometry of the gear box is complicated, some simplifications and assumptions are needed to do the finite element simulation. We start with the three dimensional finite model of the gear box which does not include the gears, shafts and bearings of the gear reducer. At first, we use static load instead of dynamic load. We use the gear load and the concept from statics to calculate the load act on the bearings and use the above results as the input to the finite element model.

Since there are big difference between the computer simulation results and experimental results, the finite element model must be improved. The gears, shafts and bearings are included in the second finite element model. But the difference between the simulation results and experimental results are bigger than before.

The contact effect between the shaft and the bearing must be included. A two dimensional simplified model is studied first, after we study the results from the two dimensional case, we simulate the three dimensional model. The results from the three dimensional model which include the gears, shafts, bearings and contact effect are very close to the results from the experiment.

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