自行車之伸縮曲柄機構設計

Design of a Retractable Crank Mechanism for Bike

徐梓皓(Tzu-Hao Hsu)

指導教授 ： 陳正光

國立臺北科技大學/機電學院/機電整合研究所/碩士(2010年)

https://doi.org/10.6841/NTUT.2010.00458

摘要

本論文提出一自行車踏板曲柄伸縮機構設計，使自行車踏板曲柄能伸縮變化長度，而達到省力有效率的傳動。本文將人在踩踏自行車時視為五連桿組模型，並將關節假設為旋轉接頭，推導其位移方程式及施力分析，在考慮人體下肢之幾何位置及大腿出力的能力下，尋找出曲柄應有的長度變化，進而設計出所需的凸輪機構使該曲柄長度變化。此機構設計由Pro/Engineer Wildfire 3.0 電腦輔助設計軟體建構3D模型，進行動態模擬分析並檢查作動過程有無干涉情形發生，再利用ANSYS Workbench 11.0軟體進行應力及位移分析，以確定所設計機構之強度，並驗證設計之機構是否符合需求；最後進行實體模型之製作，透過此原型機的實際操作驗證此設計的可行性與正確性。

關鍵字

省力 ； 機構 ； 連桿 ； 凸輪

並列摘要

This dissertation presents a retractable mechanism design of pedal crank for bicycle. It allows the length of the crank to be variable according the crank angular position in order to achieve efficient transmission. We model the bicycle and the rider’s leg as a five-bar linkage with revolute joints only, and derive the related equations for kinematic and force analysis. By taking into account the location of the human lower limb geometry and the ability of applying force of thigh, the optimum crank length for each crank position is obtained. Then, the required cam mechanism is designed according the obtained variable crank lengths. . The 3D model of this design has been constructed via Pro / Engineer Wildfire 3.0 software. The simulation has also been performed to check for interference. Then, the strength analysis is done by using ANSYS Workbench 11.0 software to verify the strength of this design. Finally, a prototype of this design has been fabricated and installed in a bicycle to confirm its feasibility.

並列關鍵字

Labor-saving ； Mechanism ； Linkage ； Cam

參考文獻

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