拖曳与启停制动模式下盘式制动器热-机耦合特性研究

STUDY ON THE THERMAL-MECHANICAL COUPLING CHARACTERISTICS OF DISC BRAKE UNDER DRAG AND START-STOP BREAKING MODES

建立起盘式制动器三维热-机耦合有限元模型,分析在拖曳制动和启停制动两种模式下制动器的热-耦合特性和摩擦振动特性,并探讨了在启停制动模式下,不同的减速行为对热-机耦合和振动特性的影响。结果表明:制动器在热-机耦合作用下,制动盘两侧摩擦片的热变形形式完全不同,导致两侧摩擦片的温度分布差异显著,活塞侧的摩擦片表面温度大于钳指侧摩擦片温度,这种温度差异也表现在制动盘两侧的盘面温度上;随着摩擦界面温度升高,制动系统的振动强度逐渐降低,但由于温度差异导致制动盘两侧的热变形程度不同,因此制动器活塞侧的振动强度大于钳指侧的振动强度;制动盘的减速行为对系统的热-机耦合特性和摩擦振动特性影响显著,在快速制动模式下制动器与外界热交换效应显著,界面温度较低,但是振动强度较大;慢速制动和分步制动模式下,界面温度迅速升高,但是由于摩擦过程较为缓慢,系统振动强度较低;尤其是分步制动的情况下,在某一阶段的振动强度有可能非常微弱。以上研究结果对认识制动系统的温度分布特性和改善制动器振动噪声问题具有一定指导意义。

A three-dimensional thermal-mechanical coupling finite element model of disc brake is established,and the thermal-mechanical coupling characteristics and friction-induced vibration characteristics in two modes:drag braking and startstop braking is studied,in addition,the influence of different deceleration behaviors on thermal-mechanical coupling and vibration characteristics in start-stop braking mode is discussed.Results show that:under the effect of thermal-mechanical coupling,the thermal deformation forms of the brake pad on both sides of the disc are completely different,resulting in significant differences in the temperature distribution of the friction discs on both sides.As the temperature increases,the vibration intensity of the brake system gradually decreases.Due to the difference in temperature leads to the difference in thermal deformation level on both sides of the brake disc.Therefore,the vibration intensity of the brake piston side is greater than that of the finger side.The deceleration behavior of the brake disc has a significant influence on the thermal-mechanical coupling characteristics and friction-induced vibration characteristics of the system.In the fast braking mode,the heat exchange between the brake and the outside environment is significant,the interface temperature is low but the vibration intensity is large.In the slow braking and step braking modes,the interface temperature increases rapidly,but the vibration intensity of the system is low due to the slow friction process.Especially in the case of step-by-step braking,the vibration intensity at a certain stage may be very weak.These results have certain guiding significance for understanding the temperature distribution characteristics of brake system and improving the brake vibration noise.