| As the urbanization course of China is faster and faster, the urban public transport appears more and more serious problems. One of effective ways to improve the problems is to develop urban rail transit. But, as its particular working environment, the urban rail transit is restricted very strictly and appears some shortcomings when it carries out transport missions. Because the urban rail vehicles always work betwween the underground stations as well as start, work and brake frequently in short time. And the vehicles often accomplish their braking by brake-shoe braking. Frequent braking will lead whiles and brake-shoes appearing deformation and breakage for their abrasion and friction fever. Otherwise, acute friction will bring much dust and pollute city's environment. Non-friction braking technology as a new-style way can solve the problems effectively. At present, the regenerative braking and resistor braking have been wildly used in locomotives and power vehicles. However, the non-power vehicles mainly use air braking as they aren't installed traction motors. As to the urban rail train which runs below 100km/h, its power vehicles have used regenerative braking as well as other non-friction braking. If the non-power vehicles could also use non-friction braking ways, it will avoid the serious problems brought by conventional brake-shoe braking. Therefore, this paper focus on researching another non-friction braking technology—rotating permanent-magnet eddy current braking, which is applied to the non-power vehicles.Firstly, the several non-friction braking technologies are compared and the advantages of rotating permanent magnet eddy current braking in the brake of railway transportation are analyzed in this paper. Based on the synthesized international status of research and application to eddy current brake, taking Chengdu metro line 1 as an example and considering its non-power bogies'structural characteristics, the overall structure of rotating permanent magnet eddy current brake is designed and every component's correlative parameters are confirmed.Secondly, based on the theory of electromagnetic induction, the braking torque of the brake is computed. The influence of structure and material to braking torque is analyzed in this paper at the same time.Then, from the basic theory of electromagnetic field, the analysis method is chosen and confirmed by comparing the three computation methods of magnetic field. The principle of rotating permanent magnet eddy current brake is analyzed and validated by 3-D Magnetic-Nodal method in ANSYS which is finite element analysis software. Besides, the analysis of 3-D static magnetic field is completed and the changeable phenomenon of the air-gaps magnetic field intensity with the rotation angle increasing is got from the analysis. In addition, the influence of disc's material, air-gap and action thickness of disc to air-gap's magnetic field is analyzed by 2-D Magnetic-Nodal method.Afterwards, on the base of the theory of thermodynamics and stress field, the brake disc's temperature and stress field are analyzed. According to the train of Chengdu metro line 1 runs full journey and returns to jumping-off point at the time of service brake application, the brake disc's temperature and stress field are analyzed in ANSYS. The rules of temperature and heat stress status as well as deformation displacement are got from the computations. Further more, the temperature's distribution at emergency brake application is also computed in the analyses. The conclusions from the analyses prove the brake designed in this paper can achieve the train's running demands.At last, according to principle of brake, a model experimental device is designed. The principle of rotating permanent magnet eddy current brake is proved out and the relations between braking force and several important factors are got from the experiment. |
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