永磁涡流缓速器制动特性分析及试验研究

Braking Characteristics and Experiment of a Permanent Magnet Eddy-current Retarder

针对重载货车下坡制动负荷过大的问题,基于永磁涡流制动原理提出一种制动力矩可无级调节的永磁涡流缓速器,用于车辆辅助制动.通过有限元法对永磁盘和涡流盘吸力特性进行分析,设计了制动力矩调节机构.通过建立永磁涡流缓速器数值分析模型,应用有限元仿真软件JMAG-Designer分析了缓速器的电磁场分布,并得到了制动力矩与转速变化的关系.通过分析温度对涡流盘材料电磁特性的影响,采用数值模拟的方法得出了制动力矩随温度影响的变化规律.试制了Φ485 mm×255 mm永磁涡流缓速器样机,对不同气隙的数值仿真数据和试验数据进行对比,并对缓速器不同涡流盘材料时的制动特性进行了台架拖动试验.结果表明:低速时数值仿真和台架拖动试验数据吻合较好.永磁涡流缓速器持续制动特性试验表明,在82 s内涡流盘表层温度上升了158℃,制动力矩下降了34.8%.

Aiming at the over load braking problem of heavy vehicle,a permanent magnet eddy current retarder was proposed as an auxiliary braking apparatus,which is based on the principle of permanent magnet eddy current braking. The retarder can adjust the braking torque. The suction characteristics of the permanent magnetic disk and the eddy current disk were analyzed by using finite element method,and the braking torque adjusting mechanism was designed. The numerical analysis model was established. The electromagnetic field distribution was analyzed by using the finite element simulation software JMAG-Designer,and the relationship between the braking torque and the rotational speed was obtained. According to the analysis of temperature influence on the electromagnetic characteristics of the eddy current disk,the variation law of the braking torque with temperature was obtained by the numerical simulation method. A retarder prototype of Φ485 mm × 255 mm was tested. The simulation data was compared with the test data at different air-gaps,and the retarder braking characteristic with different eddy current disks was studied by the bench test. Test results show that the simulation data and test data agree well at low speed. The continuous braking characteristic test shows that the increased surface temperature of the eddy current disk is 158 ℃ and the brake torque decreases by 34. 8% in 82 s.