| Load simulation in the study of water lubricated bearing characteristic is crucial,according to the present widely used way of contact loads such as,hydraulic loading,the gear loading problems such as vibration,noise and friction and wear,on the basis of the principle of electromagnetism,designed a non-contact electromagnetic loading device,and through the combination of theory,simulation and test research the dynamic and static characteristics;In order to improve the accuracy and stability of loading force,the feedback control of electromagnetic loading device is discussed.The main research work is as follows:（1）A non-contact electromagnetic loading device for water-lubricated bearings is designed and its performance is checked.Aiming at the special requirements of water-lubricated bearing load simulation,the electromagnetic loading principle was analyzed according to Maxwell electromagnetic theory,and compared with "U type" and "eight-pole type",the structure of "double E type" electromagnetic loading device was proposed,and appropriate materials were selected for each part of the device.Secondly,the device was designed to check the loading force and coil temperature rise performance,respectively,the loading force performance and coil temperature rise performance meet the design requirements.（2）Study on static characteristics of electromagnetic loading device of water-lubricated bearing.Firstly,the equivalent magnetic circuit diagram of electromagnetic loading device was established based on Maxwell electromagnetic theory and the equation of electromagnetic loading force was deduced.Then,Solidworks was used to build a 3D model of electromagnetic loading device,and Ansys18.2 was used for simulation analysis.Finally,the load test of water-lubricated bearing was carried out,and the electromagnetic force theory,simulation and test results were compared and analyzed.The results show that the magnetic induction lines are most dense at the bottom of the loading plate,the magnetic leakage of the electromagnetic loading device is very small,and the error between the electromagnetic force simulation value and the actual value is less than 7%,which verifies the rationality of the device.（3）Study on dynamic characteristics of electromagnetic loading device for water-lubricated bearings.Firstly,mathematical models of dynamic electromagnetic force,eccentricity and energy loss are established according to theoretical formulas.Then,the influence of eccentricity,current,speed and energy loss on electromagnetic force is obtained by Ansys18.2 TRANSIENT electromagnetic field and temperature field co-simulation.Finally,the dynamic electromagnetic force and energy loss tests are carried out,and the test results are compared with the numerical and simulation results.The results show that the dynamic electromagnetic force is closely related to the change of rotation speed and shaft eccentricity.With the increase of coil current and shaft speed,the total energy loss of electromagnetic loading device increases nonlinearly.The relation between energy loss components is copper loss >Hysteretic loss >Eddy current loss >wind friction loss,and the reliability of the designed electromagnetic loading device is verified.（4）Research on cascade PID control method of electromagnetic loading device.In order to improve the accuracy and stability of electromagnetic loading device,a cascade PID controller is designed.Firstly,the correlation transfer function is derived from the dynamic test fitting data.Secondly,the control system is established and analyzed by Simulink according to relevant influencing factors.Finally,pass the test.The results show that when the current is in the range of 1-2A,the accuracy is up to 64.8%,and the control system has a good effect. |
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