润滑作用机制下带式无级变速动力学系统失效行为机理研究

The metal belt continuously variable transmission has the characteristics of light weight, small size and simple structure, and is an advanced lightweight shifting mechanism that is urgently demanded with increasing energy conservation and emission reduction. However, as the continuously variable transmission is subject to large power loss, limited carrying capacity and easy failure of the power system, its method of improving reliability and transmission efficiency which is urgent to be studied. Therefore, the project intends to study the failure mechanism of the transmission power system through macroscopic and microscopic perspectives, effectively reducing power loss, improving carrying capacity, and reducing failure modes. Based on experimental and theoretical research, the change law of contact stiffness, oil film stiffness and damping between friction pairs is expounded, and the dynamic equilibrium threshold of lubrication traction is determined；The internal relationship between oil film state and dynamic thermal evolution of variable confinement space is clarified, and the dynamic coupling model of metal belt and wheel shaft assembly is constructed; Seeking the decoupling method of dynamic transfer path, revealing the failure mechanism of dynamic system under multi-fieldcoupling, establishing system critical instability security domain boundary and quantifying the safety margin ; Finally, the engineering-oriented control technology is developed to restrain the energy loss in the transmission process of the variable-speed mechanism. The completion of this project will provide theoretical basis and technical support for improving the anti-failure ability and transmission efficiency of the shifting mechanism, and will help to promote the development and application of the independent brand transmission in our country.

金属带式无级变速器具有质量轻、体积小和结构简单等特点，是随着节能减排日趋严苛下迫切需求的先进轻量化变速机构。然而，由于无级变速器受功率损失较大、承载能力有限及动力系统易失效的制约，其提高可靠性与传递效率的方法亟待研究。本项目拟通过宏微观角度对变速器动力系统失效机理的研究，有效降低功率损失、提高承载能力、减少失效形式。基于实验和理论研究，探明摩擦副间接触刚度、油膜刚度与阻尼的变化规律，确定润滑牵引动态平衡阈值；阐明油膜状态与变约束空间动态热力演化的内在联系，构建金属带、带轮轴总成动力学耦合模型；寻求动力学传递路径解耦方法，揭示多场耦合作用下动力学系统失效机理，建立系统临界失稳安全域边界，定量化安全裕度；最终开展面向工程应用的控制技术，抑制变速机构传递过程能量损失。本课题的完成将为提高变速机构抗失效能力与传动效率，提供理论基础和技术支撑，有助于推动我国自主品牌变速器的开发与应用。

无级变速器（Continuously Variable Transmission,CVT)是一个具有自身耦合效应的非单向运动系统，金属带在能量传递过程中受到多变与极限工况、宏观与微观参量的综合影响，极易导致带承载能力下降引发动力系统失效。同时夹紧力作为 CVT实现转矩传递和速比变化的关键，其变化是否准确、合理将直接影响CVT传动效率。为解决上述问题，本项目以金属带与带轮接触区域的润滑油膜作为研究对象，采用理论与实验结合的方式，辨识润滑状态与工况参数的映射关系，阐明摩擦副间油膜特性变化规律，确定金属带与带轮间油膜牵引动态平衡阈值，同时探究了钢环摩擦副之间的磨损特性，揭示宏微观工况变量耦合下动力学系统失效机理，构建系统临界失稳安全阈边界，定量化安全裕度。提出基于模型预测控制（MPC）的CVT优化控制策略，并进行仿真和整车试验，针对夹紧力优化问题，在充分考虑 CVT 滑移特性和相关约束的前提下，以滑移率为优化目标，设计了基于模型预测控制的夹紧力控制器，实现夹紧力的实时优化调整，确保其始终处于最佳状态，从而达到改善传动效率和燃油经济性的目的。. 项目负责人依托本项目研究成果，于2021年晋升副教授和博士生导师。在项目资助下，项目负责人以第一作者或通讯作者发表学术论文14篇，其中SCI/EI检索9篇；已授权中国发明专利4项。在项目执行期内，项目负责人主持吉林省自然科学基金面上项目1项，国家重点实验室开放基金2项；项目负责人将本项目研究成果与教学融为一体，培养学生创新能力，发表2篇教改论文。