【作者】 杨国俊；

【导师】 谷正气；

【作者基本信息】 湖南大学 ， 车辆工程， 2007， 硕士

【摘要】 评价汽车制动器的主要性能指标是其制动效能因数的数值及其稳定性以及制动蹄摩擦片的使用寿命。而鼓式制动器的制动蹄摩擦片上压力分布的均匀程度对这三项主要性能指标都有着直接和间接的影响。本课题采用有限元分析软件ANSYS,并且通过建立制动鼓、制动蹄、摩擦衬片三维有限元模型对鼓式制动器摩擦衬片与制动鼓之间的接触应力进行了有限元仿真。在模拟制动蹄压紧制动鼓过程中,在未知领、从蹄实际促进力的情况下,通过预加载,求出两蹄各自效能因数及实际促进力,再以实际载荷加载求解。而采用这种力加载方式,使制动蹄可以跟随鼓的变形,始终保证蹄、鼓的接触,更符合制动器的真实工作情况,同时克服了以往模型中位移加载所带来的收敛性差、计算误差大的缺点。为改进制动器结构,分析了其余结构参数不变,初始角变化对接触压力的影响,表明随初始角减少,从蹄比邻蹄的效能因数增大更为显著,从蹄靠近支撑销端衬片较原结构更为充分地参与了接触,但由于从蹄靠近凸轮端部衬片与鼓的挤压效应增强,会造成此处接触压力较原结构有一定增大,这可能导致制动器局部过载、振动噪音增大等现象。为消除由此产生的不利影响,可改变衬片初始形状,使衬片截面呈不等厚的渐缩式结构。这些分析为厂家改进设计,改善磨损均匀性和制动效能提供了理论参考。对制动鼓、制动蹄进行有限元模态分析,为降低制动噪音提供方案。更多还原

【Abstract】 The main critiaria of indexes to evaluate performance of vehicle brake are effectiveness factor, stability of effectiveness factor and working life of brake lining.However, the nouniformity of pressure distribution over brake lining has both direct and indirect influences on such criteria of indexes.By modeling drum, shoes and brake linings with ANSYS, the contact pressure distribition between brake linings and drum is simulated. In a condition of unknowing of the actuating load upon brake shoes, the effectiveness factor and actual force are caculated by applying an forehand load. Then, actual force is applied. By means of apllying force rather than displacement, the contact pressure distribution is obtained with covergence and accurarcy of the result improved.The effect of initial angle to contact pressure distribution is analyzed. The result indicates that, with the decrease of the initial angle, the effectiveness factor of the trailing-shoe increase greater than that of the leading-shoe, and the trailing-shoe lining near fixed bolt engage in contact more efficient. We can also see that, as a result of a more powerful press, the contact pressure near toe in trailing-shoe lining increases with the decrease of the initial angle. This may result in grabing, noise and overwork. To cope with the situation, we can change the shape of the brake lining to a tapered form .The above analysis provide theroretical reference to optimize the structure of the brake so as to improving the nouniformity of wear and the effectiveness factor of the brake.The finite mode analysis is conducted to find methods for lowering the brake noise.更多还原