Research On The Oil Pressure Control Mechanism Of Heavy-duty Hydraulic Automatic Transmissio

Hydraulic automatic transmission is favored by automobile manufacturers and consumers because of its smooth shift and high power transmission efficiency.Because the internal structure and working principle of hydraulic automatic transmission is very complex,coupled with foreign technology blockade of the product,the domestic research on hydraulic automatic transmission is still in a very backward state.The hydraulic system of the hydraulic automatic transmission is the core technology of the product,and it is also the field which lacks the theoretical research.The hydraulic control part of the hydraulic system is the key to lead the whole hydraulic system.Therefore,in order to break through the hydraulic pressure control technology in the hydraulic system of the hydraulic automatic transmission and provide certain theoretical research basis for the design and optimization of the hydraulic system of the hydraulic automatic transmission,this paper focuses on the research of the hydraulic pressure control mechanism of the heavy hydraulic automatic transmission as follows:(1)Taking a heavy hydraulic automatic transmission with 9 gears as the research object,the working principle of each hydraulic subsystem module is analyzed.According to the working requirements of hydraulic components and hydraulic system under different gears and working conditions,the oil pressure and flow parameters required by each oil circuit in the hydraulic system working at different gears are obtained by numerical calculation,which provides parameter support for the subsequent performance analysis,function verification and optimization research of the oil pressure control system.(2)The structure and working principle of pressure regulating valves in each hydraulic subsystem are analyzed,and the static and dynamic characteristics of each pressure regulating valve are studied in depth,to explore the influence of structural parameter changes of each pressure regulating valve on its static and dynamic pressure regulating characteristics,and to provide a theoretical basis for the subsequent simulation research of oil pressure regulating system.(3)According to the working principle of the hydraulic system,the co-simulation model of the oil pressure control part is established.Through simulation,it is verified that the oil pressure control system can realize shifting action and provide the oil pressure required by each oil circuit.On this basis,the dynamic response characteristics of each oil circuit in the process of different gear changes of the system are studied and analyzed,and the factors affecting the dynamic response characteristics of the oil pressure control system are further revealed.(4)Due to the poor dynamic response characteristics of the oil pressure control system in the process of shifting,in order to improve its performance,some parameters that have a great influence on the performance of the oil pressure control system are selected as design variables,and then ITAE criterion and ISE criterion are combined to design the objective function,and then genetic algorithm is used to optimize the design of the oil pressure control system.By comparing the dynamic response curves of different shifting processes before and after optimization,the results show that the dynamic response characteristics of the optimized oil pressure control system are obviously improved.