Study On Structure Optimization Mechanism And Manufacturing Technology Of Electromagnet For Vehicle Electric Brakes

Electric brake has been widely used in the tractor/trailer braking system abroad and what is likely to be used at home in the near future. Domestic braking system manufacturing enterprises are short of own intellectual properties about electric brakes affecting their international market competitive ability. Priority should be given to research technologies of key component (electromagnet). It can improve the tractor/trailer braking performance, provide firmly support to related business companies to participate in the international market, and also make the science and technology progress of our national vehicle brake system industry.Structural parameters and specification of electromagnet are determined by electromagnetic field theory combined with experiment study. While performance mode and conditions of electromagnet analyzed, worn away asymmetry the inner side and outer side of electromagnet is discovered that influences its service life. And dynamic analysis is made to the electromagnetic rotary torque getting electromagnet stuck. A new asymmetric electromagnet is proposed. Uniform abrasive mechanism of asymmetric electromagnet structure has been studied to provide a theoretical basis for further structure optimization of the electromagnet.With three dimensional magnetic field theory and analysis software, performance is simulated for asymmetric structure of the electromagnet to determine the optimum structural parameters. Magnetic field analysis of electromagnet is done to optimize the structure of electromagnet. The optimal structure of it is to make slots at the inner side of electromagnet. Through electromagnetic simulation analysis, the optimum slotted area, slotted width (slot number) and depth are determined. Abrasion comparison test between symmetric and asymmetric electromagnets is made. The test results show that the asymmetric structure is worn much more uniformly. The theory of abrasion for the asymmetric structure of the electromagnet is proved.Based on analysis of the different magnetic materials and performance of the electromagnetic characteristics, research of performance of the electromagnet alnico and magnetic core material has been carried out. Both pure iron and powder metallurgy are selected as suitable material of the electromagnet alnico and magnetic core. And technology of electromagnet alnico and magnetic core production studied, processing parameters of Fe base powder metallurgy is analyzed which have effects on electromagnetic properties of alnico and core, friction and wear properties of the electromagnet. Adding alloy elements appropriately can enhance the material density, and improve mouldability and electromagnetism of the Fe base power metallurgy. Breakthroughs in its key technologies are made to improving magnetic inductivity, increasing friction coefficient and reducing the wear of wheel hub. Therefore, the durability of electromagnet is improved effectively.The recipe of economical and practical new style of friction material has been made according to technical requirement of high molecule friction composites. The solved critical technologies are as follows. First, electromagnet filling material with high friction coefficient has been obtained and the stability of friction coefficient is perfect with the variation of temperature. Second, the wear resistance of electromagnet filling material is excellent and the high-temperature wear rate was low. Third, the thermal expansion consistency of alnico and filling material had been studied and it would ensure that the electromagnet alnico and the filling material would agglutinate quietly during the working process of brake. Fourth, the resistance to thermal fade and the resistance to impact strenghth of filling material had been improved. A comparison test of abradability between the new friction material and the like product abroad has been made. The test result shows that the impact strength consistency of self-developed friction material is better than the like material abroad.The execution craft of electromagnet skeleton, the solidification process of epoxy and the assembly process of electromagnet have been made. Therefore, the complete electromagnet manufacturing processes are determined.The performance test system of electromagnet and the electromagnetic test bench of durability test have been developed respectively according to the demand of experimental study.The basic principles and common methods of robust design based on Response Surface Model are introduced. A means was brought out that the robust design of Response Surface Model is incorporated with related optimization function in the tool box of MATLAB. The robust point of electromagnet is found out. The robust optimum design is introduced to the design and exploitation process of electromagnet brake first time. And it was proved that the means was feasible by the discussion, analysis and application. The robust optimum design is used in the design stage and it can make support to parameter determination of electromagnet. And it also has some referent meanings for the exploitation process of other vehicle parts.