Structure Optimize And Performance Research Of Vehicle Magnetorheological Brake

With the rise of smart cars and driverless technologies and the ever-increasing speed of vehicles,people’s requirements for vehicle safety performance are getting higher and higher.And with the development of new energy vehicles and wire control and dynamic systems,the mechanical devices used by vehicles are also moving toward integration with vehicle electronic control systems.Magnetorheological brake can not only integrate with the vehicle electronic control system,but also improve the response speed of the brake system to a great extent,shorten the braking distance of the vehicle,and thus improve the braking safety of the vehicle.Therefore,since the magnetorheological brake was put forward,it has been deeply concerned by scholars at home and abroad.The magnetorheological brake is based on the rheological characteristics of the magnetorheological fluid to provide braking torque for the vehicle.By controlling the size of the working current,the strength of the applied magnetic field of the magnetorheological fluid can be adjusted in real time to change the rheological degree of the magnetorheological fluid.Realizes real time and repeated control of brake braking torque.However,due to the influence of magnetic saturation intensity and installation space of magnetorheological fluids,magnetorheological brakes often face the problem of insufficient braking torque when used in vehicle braking.Therefore,the structure of magnetorheological brakes had been improved in this paper.To make it have a larger working area in the same radial space,thereby increasing the braking torque that the brake can provide to meet the braking torque demand when the vehicle is braking.Firstly,this paper discussed the development status of magnetorheological fluids and related devices,expounded the rheological mechanism of magnetorheological fluids and the working principle of magnetorheological brakes,and formulated the braking torque formula for double disc magnetorheological brakes.Secondly,the structural parameters and magnetic circuit of the magnetorheological brake were designed.The performance of the magnetorheological brake was simulated by using the ANSYS and Matlab simulation software,and the braking performance of the magnetorheological brake was analyzed.Finally,the structural parameters of the magnetorheological brake were optimized through the orthogonal test,which improved the utilization of the braking torque and made the structural parameters more reasonable.The optimized parameters were simulated by ANSYS software and the reasonableness of the optimized structure was verified.The simulation results showed that the magnetic flux density in the working gap gradually decreased with the increase of the working gap of the magnetorheological brake.When the working gap was greater than 0.5mm,the magnetic flux density in the working gap tended to be stable.The working current and the braking torque showed a good linear relationship within a certain range,which was easy for the development of linear control system.When the working current in the coil reached 3A,the braking torque of the magnetorheological brake reached 1134.18 mN ?,which could meet the braking demand of the vehicle.In the case of emergency braking,the maximum temperature rise of the brake was 10.6°C.Within the allowable range of the holding ability of the magnetorheological fluid,the heat dissipation conditions of the brake could be satisfied.