Abstract: To solve the problem of low magnetic field utilization rate of conventional magnetorheological (MR) brakes, a drum MR brake with internal and external fluid flow channels was proposed. By adding non-magnetic parts to the rotary sleeve and cylinder, the magnetic flux lines were meandering through six effective damping gaps in the internal and external axial flow channels, so that the brake could produce better torque performance without changing its external dimensions. The structure and working principle of drum MR brake with internal and external fluid flow channels were elaborated, and the magnetic circuit of effective damping gap under magnetic field was analyzed. Meanwhile, the mathematical models of braking torque and the temperature field were deduced and established. The simulation analysis of the electromagnetic and temperature field of MR brake was carried out by COMSOL software. According to electromagnetic field simulation, it is found that when the applied current is 2.0 A and the speed is 400 r/min, the braking torque can reach 100.69 N·m, and the torque dynamic adjustable range increases from 1.00 N·m to 29.69 N·m. According to temperature field simulation, it is found that the highest temperature under multiple emergency braking is 42.88 ℃, which is in line with the normal operating range of MR fluid.

Key words: vehicle engineering; MR brake; internal and external fluid flow channels; torque characteristic; temperature field

摘要： 针对传统磁流变制动器磁场利用率不高的问题，提出了一种具有内外液通道的筒式磁流变制动器；通过在缸筒和旋转套筒中增设非磁性器件，使得磁力线蜿蜒通过内外轴向液流通道的6段有效阻尼间隙，从而使该制动器在外形尺寸不变的前提下能产生较好的转矩性能；阐述了内外液流通道筒式磁流变制动器的结构和工作原理，并对有效阻尼间隙在磁场作用下的磁路进行分析；同时推导建立了制动转矩和温度场数学模型；基于COMSOL软件对磁流变制动器电磁场和温度场进行了仿真分析。由电磁场仿真可知，在外加电流为2.0 A、转速400 r/min时，制动转矩可达101.96 N·m，转矩动态可调范围由1.00增加至29.69；由温度场仿真可知，在多次紧急制动下最高温度为42.88 ℃，符合磁流变液正常工作范围。

关键词: 车辆工程；磁流变制动器；内外液流通道；转矩特性；温度场