自行車前變速器之新型設計

Abstract

自行車前變速器的功能是由騎乘者撥動前變速撥桿，帶動導線並牽引前變速器的撥鏈板撥動鏈條，使鏈條與所選擇的大齒盤齒片相嚙合，來達成換檔的目的。前變速器設計的優劣不僅會影響騎乘的舒適性、操縱性，甚至會影響到騎乘者自身的安全。而本文的主要目的乃是利用機械設計的方法，從規格計劃、概念設計、具體化設計乃至細部設計等步驟，設計出一符合市場需求的新型前變速器。並依據設計的結果，製造出新設計之原型機構，並加以測試。測試結果可證明該新設計的前變速器，對不同車架具有相容性，並同時可以減輕前變速撥桿的操作力。

A front derailleur of the bicycle is used to shift the drive chain to engage with the desired sprocket of the chainwheel. The performance of the front derailleur affects not only the comfort and the operation of the bicycle but also the safety of the cyclist. The main purpose of this study is to design a new front derailleur which meets the requirements of the market based on the mechanical design methodology. A set of prototypes of the new designs based on customers' requirements are manufactured and tested. The experimental results show that the new design can improve the compatibility of the front derailleur with the different frame and reduce the shifting effort.