Design and Analysis of High Efficient and Multi-path Continuously Variable Transmissions

V形皮帶無段變速傳動系統(CVT)以其操作簡單、體積輕小、變速順暢等特性，被大量使用做為速克達機車的傳動系統，相較於有段變速之系統，CVT系統的傳動效率一直處於較差的狀態。本研究目的在於探討高效率多路無段變速器之設計，基本構想為結合一固定減速比傳動裝置與無段變速系統兩種傳動模式為一體的混合型傳動系統。此傳動系統以具有高傳動效率的鏈條傳動裝置與V形皮帶無段變速傳動系統為主要構件，藉由離合器的切換，使機車在行駛中能以不同傳動模式運作。首先將現有之多路無段變速器以功能動力圖簡化機構，並且以系統合成之方法找出更多適用之系統。接著針對此系統進行運動、功流以及效率分析，並藉由Matlab撰寫程式以模擬離合器配置位置、鏈條齒比設定對系統減速比以及效率之影響。最後以歐洲ECE-40行車型態測試，模擬結果可呈現多路無段變速器所提升之效率。The advantages of simpler operation, lighter weight and smoother speed ratio change, etc, are the main reasons for the rubber V-belt continuously-variable transmission (CVT) being popular used in scooters. Compared to a variable speed system, the CVT has the low efficiency problem. The purpose of this study is to analyze and develop the design of High Efficient and Multi-path Continuously Variable Transmissions composed of the transmission with a fixed reduction ratio and continuously-variable transmission. The main components of the system are composed of highly efficient roller chain and rubber V-belt continuously-variable transmission. By incorporating clutches when engaged, the scooter could be drived in different transmission modes. In the study, firstly, current systems are presented by simple graph called “functional power graph,” and then more aapliable systems have been found by synthesis method. The dynamic property, power flow mode and transmission efficiency of the system are analized. A Matlab program has been developed to simulate the influence of clutch positions and chain gear ratio to speed ratio and transmission efficiency of system. Finally, ECE-40 driving mode is investigated, and the simulation results have been presented that the transmission efficiency of the system is to be improved