Abstract: Multi-row planetary gear mechanism is a commonly used speed change mechanism in automobile automatic transmission. It is of great significance to analyze the transmission route and calculate the transmission ratio effectively for the design and optimization of the multi-speed transmission mechanism. Take a certain 9-speed automatic transmission developed by fast as an example. The transmission consists of 6 shift actuators and 4 planetary gear rows. Based on the motion characteristic equation of the planetary gear mechanism, the transmission route of the automatic transmission is studied by lever method, and the equivalent lever diagram of each gear is established according to the basic principle of lever, so that the transmission ratio of this complex multi-row planetary gear transmission mechanism can be calculated much simpler and clearer. The research results provide theoretical reference for the analysis, design and improvement of automatic transmission power transmission route.

Key words: Automatic transmission; Lever principle; Planetary gear; Transmission ratio

摘要： 多排行星齿轮机构是汽车自动变速器常用的变速机构，有效进行其传动路线的分析和 传动比的计算对于设计优化多挡传动机构有重要意义。以法士特开发的某款 9 挡自动变速器 为例，该变速器由 6 个换挡执行元件和 4 个行星齿轮排构成。基于行星齿轮机构的运动特性 方程，利用杠杆法对该自动变速器传动路线进行研究，根据杠杆基本原理建立各个挡位的等 效杠杆图，使该款复杂的多排行星齿轮传动机构的传动比计算更加简单明了。研究结果对自 动变速器动力传递路线分析、设计及改进提供理论参考。

关键词: 自动变速器；杠杆原理；行星齿轮；传动比