摘要:随着经济的极速发展及社会的快速进步，人类所生活的环境越来越恶劣，特别是 汽车尾气承担了非常重要的一部分，电动自行车在这样的社会大背景下应运而生，特 别在中国的农村和乡镇，它不仅可以改善人们的生活，也给节能减排带来福音，但是， 目前的电动自行车存在爬坡能力不强，不够力的现状，针对这一现状，本文设计了一 套能在电机额定功率一定的情况下提升电动自行车的爬坡能力的行星齿轮传动机构。

　　　首先，论文论述了目前电动自行车传统的传动系统的基本结构和工作原理，分析 了它们的优缺点，针对目前的传动系统不能有效克服爬升坡度小的问题，提出了一套 行星齿轮减速传动系统，对其结构和工作原理进行了说明。

　　　其次，根据国家相关规定对电动自行车的技术要求，在分析电动自行车行驶过程 中驱动力和行驶阻力平衡的基础上，对电机和减速机构的参数进行了计算和选择，并 且对其是否满足要求进行了校核和验证，然后根据所选定的参数确定了齿轮传动机构 的具体结构尺寸。

最后，对全文工作进行了总结和展望。

关键词：电动自行车，传动系统，20Km/小时，齿轮减速机构

Abstract:With the rapidly development of the world economy and the society, the environment of the human beings live in is becoming more and more terrible, especially the emission of the vehicles, so ,the electrical bicycle (EB) is the trend. In the countryside of china, it’s common, not only it can improve the life level of people, but also applying for the policy of Nation. But now, the bicycle in the market have a problem that it difficulty climb，in response to this situation, the paper design a kind of planetary gear transmission, it can meet the using requirements.

　　　First , the paper discussed the basic structure and principle of the current EB’s transmission system, and analysis their advantages and disadvantages, then proposed the kind of planetary gear transmission and introduce it’s structure and principle.

　　　Then, according the Nation’s rule about the technology demand of EB, the paper calculated  and  chosen  the  motor’s  and  gears’ corresponding  parameters  based  on  the analysis of the balance equation about EB, and then checked it that if it can satisfy the driving demands, finally , make sure the gears’ exactly structure parameters .

　　　Finally, the dissertation is summarized and some precious proposal is put forward to the next research.

Key words: electrical bicycle, transmission system, 20km/h, gear system