金属带式无级变速器滑移传动机理及控制研究

With the development of new energy vehicles, continuously variable transmissions (CVTs) are becoming research focus in China. Compared with engines in vehicles equipped with manual transmissions, engines in vehicles equipped with CVTs can work in the high efficient area with the control of CVT, but CVT efficiency is low relatively, the total transmission efficiency of vehicle doesn't increase distinctly. It is significant to decrease CVT vehicle fuel consumption on how to improve CVT efficiency and it is practical significance for improving self-development capacity of automatic transmission key technologies. From the perspectives of the CVT transmission variator, the methods of increasing CVT efficiency are researched in this project. With the methods of theoretical analyses and experiments, slip characteristics are researched in this project. Relationships of primary pulley speed, torque, speed ratio, clamping force, slip ratio and transmission efficiency are researched. Combined with theoretical analyses and experimental data, the theoretical models are developed and validated. Based on the models, periodically variable clamp forces are researched. A set of completed theoretical mechanism are presented about the relationships of conditions, transmission efficiency, slip rate and belt worn. The application of the method will increase the transmission efficiency of CVT.

随着新能源汽车的发展，金属带式无级变速器成为国内的开发热点。与手动变速器相比，无级变速器的传动效率偏低，虽能控制发动机工作在最佳区域，但整车的传动效率并没有明显提高。提高无级变速器的传动效率，对降低CVT 车型油耗的意义重大，对提高自动变速器核心技术的自主开发能力具有重要的现实意义。 本项目从无级变速器变速机构的角度，研究提高无级变速器的传动效率的方法。本项目运用理论分析与试验的方法研究金属带滑移特性，找出主动带轮转速、转矩、速比、夹紧力、滑移率、磨损与传动效率的关系，结合理论分析与试验数据，建立符合试验结果的金属带滑移特性的理论模型。在模型的基础上，研究周期变化临界夹紧力的控制方法,阐明在周期变化的临界夹紧力作用下，金属带滑移传动机理，形成一套有关工况、传动效率、滑移率与磨损类型之间相互关系的完整的理论体系。本方法的应用将降低整车油耗。

为了提高无级变速器的传动效率，并确保传动的可靠性，主要做了以下工作。完善了无级变速器专用测量试验台架，包括传感器选型，TCU的设计与制作，上位机实时监测平台的开发，力学与控制模型的仿真平台的建立。采用理论分析与试验相结合的方法，研究了主从锥轮推力比的数学模型，为精确的速比控制建立了理论基础，开发了无级变速器的滑移率数学模型，并通过试验验证了理论的正确性。深入研究了金属带的滑移率特性，并研究了其传动效率、滑移率、金属带磨损的关系，为滑移率控制提供了理论基础。根据滑移特性，提出目标滑移区域的定义，滑移效率限制区域与滑移磨损限制区域。开发了滑移控制方法，控制金属带可靠工作在最优滑移区，提高了无级变速器传动效率，降低整车油耗5.2%。