電動輔助自行車之中置動力模組之設計

Abstract

本文提出一電動輔助自行車之中置動力模組構想與設計。此動力模組之動力源採用軸向磁通馬達，利用其軸向空間優勢，提供較佳的輸出表現；而減速機部分採用行星齒輪減速機，透過行星齒輪系構型的選擇以及轉位係數的搭配，使得此款行星齒輪組在動力模組上具有空間優勢，且減速比符合需求。本文動力模組結構緊實，相較於其他動力模組具有軸向空間的優勢，而同軸設計也符合一般車架安裝上的便利性。本文先定義中置動力模組之運動模式，包括動力傳遞的方向與單向軸承的搭配，並決定馬達與減速機之種類。接著依照所選擇之行星齒輪系進行齒數與轉位係數的配置。然後利用等效磁路法與有限元素法對馬達進行輸出表現計算與比較，透過兩種常見的馬達分析方法可以得到輸出轉矩誤差為9.3%。最後進行減速機量測阻力實驗，實驗結果減速機會消耗馬達之18.42%扭力輸出。

This paper proposes a novel design of a middle motor set for the electric bike with pedal assist which is also named E-bike. This middle motor set uses axial flux motor, which has advantage on space for axial direction and better performance than other motors, as its power source. The planetary reducer is the first choice for the middle motor. By choosing the type of planetary set and arranging the addendum coefficient, this planetary gear train has more advantages than others. The middle motor set comprising the axial flux motor and planetary gear reducer has compact construction and is convenient for installation on the bike.First, this paper discusses the motion of middle motor set, including power flow direction and arranged of one way clutch. Then, the type of motor and reducer are determined. Subsequently, to analyze the axial flux motor performance, the magnet circuit method and finite element method are used and the result are compared. Finally, the resistance force of the reducer is measured by experiment, the result shows that reducer will consume 18.42% of motor torque output.