Research On Performance Of Self-sensing Bearing Based On Giant Magnetostrictive And Controllable Damping Magnetic Fluid

Bearings are the key support components of the rotor-bearing system and are critical to the stable operation of the rotor system.As the rotor system develops toward high speed,high precision and high load,the performance requirements for high precision bearings are getting higher and higher.In this paper,a self-sensing bearing based on giant magnetostrictive-controllable damping magnetic fluid is proposed.The bearing is mainly controlled by the magnetic fluid under the action of external magnetic field and the micro-displacement of the giant magnetostrictive material under the action of external magnetic field.The characteristics of the two are combined to achieve vibration control of the bearing system.According to the viscosity controllable of magnetic fluid and the micro-displacement characteristics of giant magnetostrictive material,self-sensing bearing based on giant magnetostrictive and controllable damping magnetic fluid is designed in this paper.It mainly includes displacement controllable giant magnetostrictive actuator and controllable damping magnetofluid self-sensing bearing.According to the oil film thickness of ordinary oil film bearing and the elongation of giant magnetostrictive material,combined with the relationship between damping force and excitation current produced by magnetic fluid,the magnetic flux leakage coefficient method is adopted.The structural parameters and magnetic circuit parameters of the controllable damping magnetic fluid self-sensing bearing are determined.The magnetic circuit of controllable damping magnetic fluid self-sensing bearing is simulated by finite element simulation software ANSYS,and the relationship between magnetic induction intensity and applied current in the working area is obtained,which provides a theoretical basis for the viscosity damping control of magnetic fluid.A controllable damping MHD self-sensing bearing test platform is built by using eddy current sensor,data acquisition card,servo motor and so on.The instantaneous center trajectory of the rotor rotation at different speeds and currents and the response time of the controllable damping magnetofluid self-sensing bearing are obtained by experiments.The results show that the response time of the rotor system can be controlled by changing the applied current,and the amplitude of the axial vibration decreases obviously with the increase of the applied current,and the response time of the rotor system can be controlled by changing the applied current,and the amplitude of the axial vibration decreases obviously with the increase of theapplied current.Through the analysis of the experimental results,it can be seen that the controllable damping magnetic fluid self-sensing bearing has excellent damping and controllable characteristics.It provides a theoretical basis and experimental basis for the next step of the technical development and application of self-sensing bearing based on giant magnetostrictive and controllable damping magnetic fluid.