Study On Output Characteristics Of Compound Driven Magnetorheological Valve And Its Application In Shock Absorber

Magnetorheological valve is a hydraulic control and adjustment element with magnetorheological fluid as the working medium.Different from traditional hydraulic valves,there is no relative movement between the valve core and the body.It has the advantages of low machining accuracy,relatively simple structure,and easy control.However,the safety and reliability of the existing magnetorheological valve is low,and the energy consumption is large,which limits the application range of the magnetorheological valve.Based on this,this paper designs a compound-driven magnetorheological valve whose working magnetic field is generated by the excitation coil and the toroidal permanent magnetic field,and it can still maintain a certain working performance under the condition of no excitation current,and the damping characteristics of the magnetorheological valvecontrolled shock absorber are studied.The main contents include:(1)A compound driven magnetorheological valve was designed innovatively.The specific structure size is designed,the magnetic circuit distribution is calculated and analyzed,and the rationality of the structure is verified.At the same time,the entire effective flow passage of the magnetorheological valve is analyzed,which is divided into axial circular pipe flow passage,radial disc flow passage and axial circular flow passage,and the pressure drop of each section of the flow passage is calculated separately,and the mathematical model of total pressure drop of valve is established.(2)A two-dimensional model in Maxwell was established,and the effects of key dimension parameters in the magnetorheological valve on the direction of magnetic field lines,magnetic field distribution and magnetic induction intensity at each damping gap were simulated and analyzed.At the same time,the pressure drop mathematical model was used to analyze the change of pressure drop with current under each parameter.The simulation results show that the permanent magnetic field generated by the ring magnet can effectively increase the total magnetic field strength;the thickness of the ring magnet determines the rate of increase of the voltage drop with the current,and the inner diameter of the ring magnet only affects the initial value of the voltage drop without excitation current;the larger the radial gap,the smaller the average magnetic induction at the gap and the smaller the pressure drop under the same current.The pressure drop of the magnetorheological valve increases with the increase of the flow,and the current has no effect on the growth rate of the pressure drop with the flow.In addition,taking the pressure drop and adjustable coefficient of the valve as the objective function,the modeFRONTIER software is used in conjunction with Maxwell to optimize the relevant parameters that affect the valve performance,determine the final structural size of the valve,and compare it with the performance of the magnetorheological valve before optimization.analysis.(3)A composite-driven magnetorheological valve characteristic test bed was built,and pressure drop experiments were carried out.The results show that: the change of load has little effect on the pressure drop;the overall pressure drop of the magnetorheological valve in the loading stage is smaller than that in the unloading,which indicates that there is still hysteresis phenomenon in the valve;there is a certain gap between the simulated pressure drop and the measured,but the trend of the pressure drop with current change is consistent.(4)A dual-pole external magnetorheological valve-controlled shock absorber is proposed,and the mathematical model of its output damping force is established.Simulink is used to simulate and analyze the dynamic performance of the shock absorber.The simulation results show that the shock absorber can maintain a high output damping force under different amplitudes and frequencies,and the damping force increases with the amplitude and frequency,that is,the vibration speed,while the current is constant.At the same time,in the case of no current,the damper can still maintain a certain damping force,which ensures the safety and reliability of the damper,and also verifies the feasibility of the combination of the composite drive magnetorheological valve and the damper.