本文主要探討目標為齒輪組之動態響應分析與齒輪故障時對系統動態特性的影響。研究方法為利用有限元素軟體ANSYS建立無裂紋齒輪組與有裂紋齒輪組的幾何模型，首先分析出齒輪接觸點的接觸力與變形量後計算出齒輪的嚙合剛度，接著討論當裂紋位置改變或齒輪被施予的負載改變時對於齒輪嚙合剛度的影響，並為了縮短分析齒輪嚙合剛度的時間，可將齒輪的嚙合剛度簡化成二個部分分別求取後再串聯，最後再以集中質量法，將以等效質量、等效彈簧、等效阻尼建立起齒輪動態系統模型，將齒輪的嚙合剛度代入齒輪的運動方程式，並以數值方法求解齒輪的動態響應，分析無裂紋齒輪組與有裂紋齒輪組在各種不同轉速下以頻譜分析找出有裂紋齒輪的故障特徵。 ;The target of this research is to study the effects of a tooth crack to the dynamic characteristics of a spur gear pair. A finite element software, ANSYS, is used for the simulation. The meshing stiffness of the gear pair is calculated by analyzing the contact force and deformation. The stiffness is dependent of the crack position and the contact condition. For reducing the calculation time, each gear can also be divided into two smaller parts which is analogical to springs. Then, the gear dynamic model is developed by the lumped-parameter method for the vibration response, and the equations of motion are derived. The dynamic responses of the gear pair are solved by using the numerical method. The features of dynamic signals are found for spur gear pair with the tooth crack and compared with those for gears with no crack.