以彈性皮帶達成自動變速的新式理論之驗證

Abstract

無段變速技術（CVT）自1877年誕生以來，開始在變速器市場上展露頭角，預計將成為未來變速器的主流。但縱觀目前所有型式的變速器，改變速比皆牽涉力的傳遞時作用在輸入軸與輸出軸上的有效半徑比。本研究的目的為分析並以實驗驗證一種全自動無段變速的新式理論。 此新式變速理論使用一條可以彈性變形的皮帶聯結固定尺寸的驅動輪與被動輪，速比的改變並非改變皮帶於皮帶輪上之有效半徑，而是利用皮帶本身在負載增加時被拉長而使速比下降。此種新式理論可以簡化變速器設計並提升其效率。將來此種變速器不需人為操作，是完全自我偵測、自我調整的全自動無段變速器。 本論文首先提出本新式理論的中心概念與假設，再以皮帶傳動的力學討論對此新式理論加以分析，並依此新式變速方式的需求設計變速器及其傳動皮帶，最後以實驗的方式驗證此新式變速理論。 實驗結果成功地在小負載與低轉速的情況下實現此種新式變速理論。以皮帶受不同張力所產生不同的彈性變形來改變速比及扭力比在本研究中被驗證為可行的，並且針對實驗過程中所發現的現象提出供以後研究方向與設計改良的建議，已為此種新式變速理論奠定基礎並提供參考。

From 1877, the continuously variable transmission (CVT) showed up and became popular in the transmission market, and it is expected to be the main stream of transmission in the future. This research attempts to verify a new principle for automatic continuously variable transmission which is achieved by elastic deformation of an elastic belt. Unlike traditional transmission, this new approach does not rely on the gear ratio or the radius of the driving and driven wheel to change the speed ratio. The speed change in this new approach is achieved by an elastic belt on two fixed-diameter pulleys. The belt elongates in proportion to the load applied, and the driving pulley has to rotate more to accommodate the increased length of the belt due to the load increase. This means the speed of driven pulley will automatically reduce when the load increase. This new CVT is self-sensing, self-adjusting, and fully automatic. This thesis introduces the main concept and assumption of the new principle, conducts mechanic analysis, designs and builds the transmission model and an elastic belt, and experimentally verifies the new principle. The result of experiment shows that the new transmission succeeds when the load is small and the speed is low. It proves the feasibility of using the deformation of the elastic belt to change speed ratio and torque ratio. Based on this result, a whole new transmission may be designed, manufactured, improved, and used in the future.