附件驱动系统中自动张紧器的动态特性实测与建模分析

摘要

Test methods and parameters assessment for the dynamic performances of an automatic tensioner in an engine front end accessory drive (FEAD)system were investigated.The dynamic performances of the tensioner included dynamic stiffness and loss angle.The influences of pre-torque,excitation amplitude and excitation frequency on the dynamic characteristics of the tensioner were measured and analyzed.Considering the pre-torque,the spring stiffness and damping coefficient of the tensioner,and the moment of inertia for the tensioner arm,a hysteresis model used for the relation between the torque and angular displacement of the tensioner was built.Parameters of the model were identified with the least-square method.The dynamical properties of the tensioner were calculated and compared with the test data, the correctness of the presented hysteresis model was validated.Moreover,the equation of rotational vibration for the tensioner arm in a FEAD system was established.In the equation,the dynamic stiffness and equivalent damping of the tensioner were calculated based on the hysteresis model of the tensioner.Then,the rotational vibration responses of the FEAD system were calculated and compared with the test data,they agreed well each other.The results showed that the hysteresis model of the tensioner can provide a reference model for rotation vibration calculation of a FEAD system.%介绍了发动机前端附件驱动（Front End Accessory Drive，FEAD）系统中自动张紧器动态特性的实验测试方法和评价参数。测试和分析了预载扭矩、激振频率和激振振幅对张紧器动刚度和滞后角的影响。基于张紧器的预载扭矩、弹簧刚度、阻尼系数和张紧臂转动惯量四个参数，建立了表征张紧器扭矩-角位移关系的迟滞回线模型；采用最小二乘方法识别出张紧器迟滞回线模型的模型参数。对比张紧器动态特性的实测值和计算值，结果表明张紧器迟滞回线模型的建模方法是正确性。由张紧器扭矩-角位移关系曲线换算出张紧器的动刚度和等效粘性阻尼，建立了FEAD系统中张紧臂的旋转振动方程。FEAD系统旋转振动响应幅值的计算值和实验值吻合较好，这说明表征张紧器扭矩-角位移关系的迟滞回线模型，能为FEAD系统旋转振动的计算提供模型参考。