Study Of Fluid-solid Coupling Simulation And Experiment On The Power Steering System Of A Commercial Vehicle

The thesis were carried out of a collaborated research project focusing on the hydraulicpower steering system of a commercial vehicle between the FAW-RDC center and JilinUniversity. In this thesis, a fluid-solid coupling model have been made to simulate thesteering performance of the commercial vehicle, which includes vary of the assistedhydraulic power pressure reacting to different input and the handling performance.Furthermore, an analysis was carried out about the crucial factors of the power steeringsystem affecting the steering performance and the way these factors act. To achievethese, first a theoretical study of power steering system of the commercial vehicle hasbeen done to gain a deeper look into the components of the HPS and the mechanismwhere they interact to work together, in this course a recirculating ball steering gearwas dissembled to help understanding the mechanism and to gain the key parametersfor modeling. After this, a fluid-solid coupling model of the HPS was made inAMESim and a bench test of the HPS has been done to the verification of the model,the test curve and the simulation curve showed good fitness. Finally, a sensitivityanalysis on the main parameters of the steering system was made to find out the keyfactors affecting the steering performance and the way they did to the performancecurve. In the end, some conclusions has been made.The results of the sensitivity analysis shows that the structural parameters of therotary valve, including the width and length of the notch on the valve port and thewidth of the pre-open gap make a distinguished influence on the steering performancecurve, and parameters like the pump flow, the angular transmission ratio, the leakagecoefficient of the piston and the stiffness of the torsion bar also make notable effects onthe steering performance. Varied factors act differently on the performance curve. Atlast some advice was given to help the design improvement and matching of the steering system.As a core system of a vehicle, steering system play a crucial part in car handlingand stability. This study would do some help in improving the steering performance ofvehicles.