Abstract: Due to the simple mechanism and high mechanical efficiency of synchronizer-less mechanical automatic transmission, it can improve energy utilization efficiency and range in electric vehicles. In order to promote the application of synchronizer-less mechanical automatic transmission to electric vehicles, focusing on its problems of shift shock and power interruption, a dynamics model of the engagement sleeve and engagement gear ring is established to investigate the shift shock mechanism and the factors affecting the shift quality. Simulations were conducted in AMEsim to analyze the changes of shift shock, shift time and other shift quality indicators under different initial speed difference and shift force conditions. The results show that the larger the initial speed difference between the engagement sleeve and the engagement ring, the longer the shift time and the larger the shift shock; the larger the initial shift force, the shorter the shift time, but the shift shock becomes larger. When the initial conditions of the shift process are high shift force and low speed difference, both shorter shift time and lower shift shock can be obtained and the shift quality is improved.

Key words: Synchronizer-less; Automatic transmission; Shift shock; Shifting process

摘要： 由于无同步器式机械自动变速器结构简单，机械效率高，装备在电动汽车上能提高能 量利用效率，提升续航里程。为促进无同步器式机械自动变速器在电动汽车上的应用，针对 其换挡冲击大、易出现动力中断的问题，建立了接合套和接合齿圈的动力学模型，以探究换 挡冲击机理和影响换挡品质的因素。在 AMEsim 中进行了仿真，分析了不同初始转速差，换 挡力条件下换挡冲击，换挡时间的变化。结果表明，接合套和接合齿圈初始转速差越大，换 挡时间越长，换挡冲击越大；初始换挡力越大，换挡时间越短，但换挡冲击变大。当换挡过 程初始条件为高换挡力和低转速差时，既能获得较短的换挡时间，又能得到较低的换挡冲击， 换挡品质得到提升。

关键词: 无同步器；自动变速器；换挡冲击；换挡过程