盘式制动器接触压力与热机耦合特性仿真分析

Computational Investigation into Disc pads Pressure Distribution and Thermomechanical Coupling Characteristics of Brake Pads in Disc Brake

摘要:

针对通风盘式制动器，根据形状、尺寸设置刚性面模拟活塞侧和钳指侧制动块的法向作用力，建立了三维瞬态热机耦合有限单元模型，进行了紧急制动工况下盘块接触压力和制动块热机耦合特性的计算与分析.分析表明，摩擦力引起的载荷转移效应会促使盘块接触压力总体上向进摩擦区方向偏移，时变的活塞侧和钳指侧盘块接触压力分布完全不同，会受到制动器结构、法向力和摩擦力的动态变化以及制动盘热翘曲变形的联合影响；摩擦生热量的动态变化、制动盘的周向温度梯度以及衬片的径向接触压力梯度导致制动块复杂的温度分布特征；摩擦衬片主要产生由法向力引起的压应力，且应力分布与接触压力分布极为相似；制动盘的热翘曲情况会显著影响摩擦衬片的热变形模式以及变化趋势.

Abstract:

Finite element model (FEM) of three dimensional transient thermo mechanical coupling dynamics was established for a ventilated disc brake, in which two rigid surfaces were used to simulate the normal force applications on both piston side and finger caliper side, with different shapes according to their respective structures. Based on this model, the contact pressure between the disc and the two pads, the thermo mechanical coupling characteristics of two pads were calculated under a certain emergency braking condition. The analysis results show that load transfer effect caused by friction force leads to the excursions of the pressure distribution center in the direction of entering friction area. However, the time varying contact pressure distributions on both sides are different, which are affected by brake structures, dynamical normal forces and friction forces, and the disc thermal distortion. The complicated temperature distribution of brake pads is caused by the varying frictional heat, the circular temperature gradients of the disc and the radial contact pressure gradients. The linings generate mainly pressure stress whose distribution is similar to that of contact pressure. The lining deformation patterns and their changes are strongly influenced by disc thermal distortion.