电动汽车两挡变速器结构设计与换挡性能分析

Structural Design and Shift Performance Analysis of Two-speed Transmission for Electric Vehicles

摘要:

为解决电动汽车传统无离合器两挡机械式自动变速器(Automated mechanical transmission,AMT)换挡困难及动力中断问题,本文提出一种无离合器、换挡可分离的两挡机械式自动变速器( Unidirectional-clutch integrated automated mechanical transmission,Uni -AMT)技术方案。 通过关键零部件参数与传动比计算搭建系统三维模型,分析换挡过程并建立同步器机械同步过程的数学模型,进而构建同步器多体动力学模型。 通过仿真对比了传统 AMT 与 Uni-AMT 在不同换挡力工况下换挡性能。 搭建了 Uni AMT 实物试验台,并进行试验验证。 试验结果表明,与传统 AMT 换挡方案相比,Uni AMT 在换挡完成时间与换挡平顺性方面均具有显著优势。 研究结果为电动汽车多挡变速器技术创新提供了新路径,对推动纯电动力技术发展具有重要意义。

Abstract:

Aiming to address the challenges of difficult shifting and power interruption in conventional clutchless two-speed automated mechanical transmissions ( AMTs ) for electric vehicles, a novel clutchless and shift-separable two-speed AMT, termed Uni AMT, was proposed.Based on the calculation of key component parameters and transmission ratios, a three-dimensional model of the transmission system was established.The shifting process was analyzed in detail, and a mathematical model describing the mechanical synchronization phase of the synchronizer was developed.Furthermore, a multi-body dynamics model of the synchronizer was constructed to investigate the dynamic characteristics during gear shifting.Comparative simulations were conducted to evaluate the shifting performance of the conventional AMT and the proposed Uni-AMT under different shift-force conditions.To verify the feasibility of the proposed scheme, a Uni-AMT experimental test bench was developed,and a control system based on dSPACE was implemented for experimental validation sindicated that, compared with the conventional AMT shifting strategy, the proposed Uni AMT reduced the shift impact force by approximately 26% and shortened the shift completion time by about 22% throughout the shifting process.In addition, the Uni AMT exhibited superior shift smoothness, shorter synchronization duration, and improved impact resistance under various operating conditions.The proposed transmission architecture demonstrated significant advantages in both shifting efficiency and driving comfort.The research result can provide an approach for the development of multi-speed transmissions for electric vehicles and offer valuable theoretical and engineering support for advancing electric powertrain technologies.