Abstract: The starting characteristics model of CPMGs were put forward based on rotor dynamics. Influences of gearing ratio， starting position and output speed of driven rotor on the starting characteristics of CPMGs were analyzed. By the transient finite element method， three CPMGs were established with same structural parameters and different gearing ratios， the starting characteristics were analyzed in different gearing ratios. When the gearing ratio containing as 0.75， starting characteristics are the best. Based on the theorem of moment of momentum， the influences of the starting positions with the driven rotor on the starting characteristics were given， and the optimum starting position was obtained when the output torque was equal to the load torque. By calculating alternating periods of output torques， the relationship between the output speeds and alternating periods was obtain， when the driven rotor output speed is larger， the alternating period of output torques is larger， the CPMGs are easy to start.

Key words: concentric permanent magnetic gear（CPMG）； starting characteristic；starting position； , alternating period

摘要： 采用转子动力学原理对同心式永磁齿轮（CPMG）的启动特性进行数理建模，分析了CPMG传动比、启动位置及从动转子输出转速对启动特性的影响。基于瞬态有限元方法，建立了3种尺寸相同、传动比不同的CPMG有限元模型，分析了不同传动比下的启动特性，当传动比含有0.75时，启动特性最佳。基于动量矩定理，给出了从动转子启动位置对启动特性的影响关系，当输出转矩等于负载转矩时为最佳启动位置。通过计算作用在从动转子上转矩的交变周期，得出了从动转子输出转速与输出转矩交变周期之间的关系，当从动转子输出转速较大时，输出转矩的交变周期也较大，此时CPMG较易启动。

关键词: 同心式永磁齿轮, 启动特性, 启动位置, 交变周期