CAJ | 학술논문

针对重型商用车采用固定助力特性的液压转向系统引起高速操控失稳的问题，设计了具有可变助力特性的比例阀旁通流量式电控液压转向系统。运用AMESim建立了包含各子模型的系统仿真模型，通过分析转向阻力矩与车速的关系，获得了比例阀电流与车速的特性关系，进而对不同车速下的比例阀位移特性及典型车速下的助力特性进行了仿真分析，结果显示：40 km/h和80 km/h的最大助力油压比低速20 km/h的最大助力油压分别下降了约50％和65％，满足了重型车高速操控性要求。在此基础上进行了台架试验，结果表明：该系统典型车速下试验和仿真的助力特性曲线变化趋势、饱和区最大油压以及操纵力矩均基本一致，可很好的兼顾重型车低速转向轻便性和高速操控性。
침대중형상용차채용고정조력특성적액압전향계통인기고속조공실은적문제，설계료구유가변조력특성적비례벌방통류량식전공액압전향계통。운용AMESim건립료포함각자모형적계통방진모형，통과분석전향조력구여차속적관계，획득료비례벌전류여차속적특성관계，진이대불동차속하적비례벌위이특성급전형차속하적조력특성진행료방진분석，결과현시：40 km/h화80 km/h적최대조력유압비저속20 km/h적최대조력유압분별하강료약50％화65％，만족료중형차고속조공성요구。재차기출상진행료태가시험，결과표명：해계통전형차속하시험화방진적조력특성곡선변화추세、포화구최대유압이급조종력구균기본일치，가흔호적겸고중형차저속전향경편성화고속조공성。
To overcome the problem of losing handling stability at high speed caused by the constant assist characteristic of Hydraulic Power Steering( HPS) to heavy-duty commercial vehicle, a steering system of electro-hydraulic proportional valve by-pass flow of Electrical Controlled Hydraulic Power ( ECHPS)with varied assist characteristic was designed .A simulation model including sub models was established by using AMESim.The valve current varied by vehicle speed was studied by analy -zing the relationship of steering resistance torque and vehicle speed and the valve displacement char-acteristic at different speed and the assistant characteristic of ECHPS under three typical vehicle speeds were simulated.The results show that the maximum assist oil pressure at 40 kmh/and 80 km/h deceases by about 50% and 65% respectively than that of 20 km/h, meeting the handling stability requirement at high speed.Bench test of ECHPS was carried out and the results show that the changing tendency of assistant characteristic, maximum oil pressure in saturation region and han-dling torque are coincident in simulation and test at different speed, that meets the requirement of steering easiness in low speed and handling stability in high speed.