Research And Design Of HMT System Based On Distributor Of Dual-cam-rotor Vane Pump For Passenger Cars

HMT system,also known as the mechanical hydraulic double flow transmission system,is a hybrid transmission system which combines mechanical transmission and hydraulic transmission.The system takes into account the characteristics of the stepless speed regulation of the hydraulic system and the high efficiency of the mechanical system,and can achieve stepless speed regulation while maintaining high efficiency.HMT system is divided into two modes according to the way of shunt drive: external shunt and internal shunt.The external shunt mode adopts planetary gear mechanism as the distributor,and the internal shunt mode adopts pump or motor as the distributor.In this paper,a new type of HMT system is designed based on the internal distributary mode,and the specific work is as follows:(1)The transmission relation between internal and external shunting systems is analyzed and calculated,and the relationship between transmission ratio and the transmission power of mechanical and hydraulic road is obtained under two different modes.Through comparative analysis,it is found that the transmission ratio of the power re-circulation in the internal shunting mode is smaller than that of the external shunting mode.The structure of the double cam rotor vane pump as the transfer case is analyzed under the internal shunt mode.(2)The internal shunt HMT transmission scheme is designed.The shunt function and clutch function of the distributor,the regulating function of the hydraulic motor to the transmission ratio of the system,and the control function of the valve component are introduced.The working state of the system under three operating conditions is analyzed.The relationship between the displacement of the hydraulic motor and the transmission ratio control of the system is calculated.The results show that the speed ratio of internal shunt HMT system is not equal to the torque ratio due to the volumetric efficiency.(3)Taking a kind of A0 class car as the research object,the plan of replacing the original 5D+1R gear with 3D+1R gear is put forward.In this plan,the original vehicle’s reverse gear,direct gear and overspeed gear are retained,the remaining stall is replaced by HMT system,so as to give full play to the advantage of the internal shunt HMT system’s stepless speed regulation.The specific parameters of each component are calculated according to the target model.(4)Based on Simulink,the modeling and Simulation of HMT system is carried out,and the relationship between the displacement of the hydraulic motor and the vehicle speed under the economic and dynamic strategy is obtained.The dynamic and economic characteristics of the HMT system under the throttle opening of 51% are analyzed.(5)The experimental device was designed and the content of the experiment was established.