【作者】 宋宇；

【导师】 丁柏群；

【作者基本信息】 东北林业大学 ， 载运工具运用工程， 2011， 硕士

【摘要】 磁流变液可在磁场作用下发生瞬间、连续、可逆的流变效应,这种特性使磁流变液适合用于汽车制动器,通过合理的结构设计、磁路电流控制,能够实现磁流变液粘度的快速、连续、无级的变化,从而达到按照实际需要控制制动力矩的目的。当辅助以车轮滚动、滑动状态检测,还可以响应路面附着系数的变化实时调节制动力矩,达到较传统ABS更精确的防抱死效果,同时能实现制动过程中的全部电控,符合未来智能汽车的发展方向。论文从微观和宏观两方面阐述了磁流变体这种流变效应产生的机理,介绍了磁流变液的组成和制备方法；探讨了发展磁流变制动器的实际需求和可行性；在分析磁流变液器件的工作原理和车辆制动理论的基础上,设计了一种工作在剪切与流动复合模式下的叶轮式磁流变液制动器,以及相应的电磁控制装置,使制动器在控制电流为3A时输出的制动力矩能够达到1656N·m,从而在有限的轮内空间满足中小型车辆制动力矩的需求；采用电磁离合器与磁流变制动器工作相结合的方案设计,在驱动轮和非驱动轮上合理布置,有效地避免了随动损失。运用MATLAB/Simulink,建立相应的仿真模型,分别从制动器结构参数对制动力矩的影响、模拟ABS制动过程和若干工况下的制动器的散热三个方面进行了仿真。结果表明,制动器制动力矩与磁感应强度呈现对数变化规律,与工作间隙呈现负指数变化规律；叶片的径向尺寸、叶片数量和叶片厚度对制动力矩都有较大影响；控制电流与制动力矩的响应是一种非线性且迅速饱和的关系,通过矫正电路的校正可以使其具有适合操作习惯的线性关系；磁流变制动器在ABS制动过程中也能发挥良好的制动效能；制动器在不同工况下制动时的温升在保持在允许的范围内。更多还原

【Abstract】 Magnetorheological fluid can produce a successive, reversible and instantaneous rheological effect in the magnetic field. This kind of rheological characteristic makes MRF suitable for automobile brake, and it can realize a fast and continuous and stepless viscosity of MRF through a rational design of structure and current controls in magnetic circuits, so as to achieve the purpose of controlling braking torque according to actual needs. When aided by wheel rolling and sliding state detection, it can regulate the braking torque timely according to the variation of tire-road friction coefficient to achieve a more accurate antilock brake effect than traditional ABS, and the system can realize a electronically controlled braking process completely, and so it can meet the futural development direction of intelligent vehicle.The paper expounds the mechanism of the rheological effect from macro and micro two-aspects, and introduces the component and preparation methods of MRF; In addition, it discusses the actual needs and feasibility of developing MRF brake; Based on the analysis of working principle of MRF devices and the theory of vehicle braking, The article designs a kind of impeller-type MRF brake working on the mode mixed shear and flow mode and the corresponding electromagnetic control device to make the brake produce a output of 1656N·m brake torque while the current is 3A as the input, so as to satisfy braking torque requirements of small and medium-sized vehicles in the limited wheel-inner-space; Adopting a design work of integrating the electromagnetic clutch with brake through decorating reasonably on the driving and driven wheels that can effectively avoid following loss.The corresponding simulation model established on three aspects which range from the influence of brake structural parameters on the braking torque and the simulation braking process of ABS to the simulation of brake cooling under several working conditions are simulated through MATLAB/Simulink software. The results show that the relationship between its braking torque and magnetic induction presents a logarithmic change rule, while the corresponding relation with the working gap presents a negative exponential law; The radial dimensions, number and thickness of blades have considerable influence on braking torque respectively; As the response between the current and braking torque displays a nonlinear and rapidly saturate relationship, The redress through correctional circuit can make it present a linear relationship which is suitable for operation habit; Magnetorheological brake can also play a good braking performance in the ABS braking process; The braking temperature of brake is kept in allowing range.更多还原