商用车AMT制动器性能影响因素分析研究

Research on Factors Affecting Performance of AMT Brake on Commercial Vehicle

机械式自动变速器(AMT)是一种能够根据车辆运行状态和车辆行驶道路环境实现自动换挡的变速器装置。商用车上常用的AMT是由压缩空气提供动力源,由变速箱控制单元(TCU)根据软件逻辑控制电磁阀实现离合器的分离与结合以及变速箱的选换挡功能。商用车AMT换挡过程中的同步过程由变速箱自动完成,国内外主流商用车AMT均采用结构更加简单、成本更加低廉、质量更加可靠的滑套结构。相比于同步器,滑套结构在升挡过程中需要变速箱制动器(TB)来实现同步过程。文章分析了AMT制动器性能的影响因素,并设计具体的实验测试方法在实验测试台架上测试各个因素对TB性能的影响。分析研究表明,TB摩擦片的直径影响制动斜率,直径越大,制动斜率越大;TB摩擦片的数量对响应时间和制动斜率有影响,数量越多,响应时间越快,制动斜率越大;TB气道通径影响响应和退出时间,气道通径越大响应和退出越快;气源压力影响TB的制动斜率,压力越大制动斜率越大。文章的研究结论对商用车AMTTB的设计研究以及车辆的标定测试提供了支持。

Automaticed mechanical transmission(AMT)is a transmission device that can automatically shift gears according to the operating state of the vehicle and the road environment of the vehicle.The AMT commonly used in commercial vehicles isshifting powered by compressed air,and the transmission control unit(TCU)controls the solenoid valve according to the software logic to realize the disengage and engage of the clutch and the gearshifting of the gearbox.The synchronization process of commercial vehicle AMT shift is automatically completed by the gearbox,and the mainstream commercial vehicle AMT at home and abroad adopts the dog clutch structure with simpler structure,lower cost and more reliable quality.Compared to synchronizers,the dog clutch structure requires a transmission brake(TB)to synchronize the process during upshift.This paper analyzes the factors affecting the performance of AMT TB,and designs a specific experimental test method to test the effects of each factor on the performance of TB on the experimental test bench.The test result has shown that the diameter of TB friction plates affects the braking rate,and the larger the diameter,the greater the braking rate;The number of TB friction pads has an impact on response time and braking rate.The more the number,the faster the response time and the greater the braking rate;The TB airway diameter affects the response and exit time,and the larger the airway diameter,the faster the response and exit time;The air source pressure affects the braking rate of TB,and the greater the pressure,the greater the braking rate.The conclusions of this paper provide support for the design and calibration work of AMT TB on commercial vehicle.