水润滑轴承加载装置电磁力动态变化机理研究

The electromagnetic force of electromagnetic loading device is unstable in dynamic load simulation test, in order to provide accurate load for performance study of water-lubricated bearings in hydraulic machinery including water pumps, water turbines, and so on, the dynamic change mechanism of electromagnetic force is studied. Firstly, the dynamic change mathematical model of electromagnetic force for loading device is deduced in theory. Secondly, the physical model of electromagnetic loading device is established, the finite element analysis is carried out, and the change rules of electromagnetic force, magnetic reluctance torque, magnetic flux density and other parameters are obtained. Finally, the dynamic test of electromagnetic force of loading device is conducted. The results of comparison and analysis among theory, simulation and test show that the dynamic changes of electromagnetic force are closely related to speed variation and eccentricity of shaft. With the increase of shaft speed, the eddy current and skin effect on surface of electromagnet are gradually enhanced, the magnetic resistance of loading plate surface increases, and the electromagnetic force decreases gradually. The shaft eccentricity results in the change of gap between shaft and magnet, and the electromagnetic force changes. Under the excitation of electromagnet current（0.5~1.5 A）, when the shaft has no eccentricity or not, the maximum error of simulation and test results of electromagnetic force are separately 6.8%, 6.1%.