本研究提出一系統化方法，設計新型八桿越野摩托車後懸吊機構，其具有比現有機構更高的槓桿比。文中首先定義機構的槓桿比，並介紹後懸吊機構的應用，並以Honda公司的六桿Pro-link作為設計範例，計算其槓桿比。再者根據槓桿比定義，指定新的槓桿比，且依據現有六桿與八桿後懸吊機構訂定設計需求與限制。接著利用顏氏創意性機構設計法，系統化地合成出74種可行之新型八桿後懸吊機構，並擇一可行設計進行運動分析，及利用最佳化方法進行尺寸合成。與現有機構作比較，本研究所設計的新型八桿後懸吊機構具有較高的槓桿比，表示該設計在承受輕微震盪時較軟，反之劇烈震盪時較硬。最後，建立新型八桿越野摩托車後懸吊機構之3D模型，以並證明此設計是可行的。

This study provides a systematic design approach of new 8-bar linkage rear suspension mechanisms for motorcrosses with a higher leverage ratio than those of existing designs. At first, the leverage ratio of a mechanism is defined and the application for the rear suspension mechanisms is introduced. The leverage ratio of existing 6-bar Honda pro-link, taken as an example, is calculated. According to the definition of leverage ratio, the desired leverage ratio for a new design is discussed. Based on the existing designs of 6-bar and 8-bar rear suspension mechanisms, the design requirements and design constraints are concluded, and Yan’s creative mechanism design methodology is applied to generate 81 design concepts systematically in which 74 are feasible new 8-bar rear suspension mechanisms. And, a suitable mechanism is selected for kinematic analysis. Then, optimum design method is used to synthesize the links’ dimensions of the new 8-bar design based on the desired leverage ratio. The new synthesized mechanism is further analyzed to gain the leverage ratio and compare with those of existing designs. The result shows that the designed 8-bar linkage mechanism performs better than existing designs in leverage ratio aspect. This means that the shock of the new 8-bar linkage mechanism is softer on the little bumps and harder on the big bumps. Finally, based on the dimensions of the new design, the corresponding 3-D model is built and proved that it is feasible for product development.

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