Study Of The Electrohydraulic Wet Clutch Buffer Of Hydraulic Mechananical Transmission

Hydraulic mechanical variable transmission (HMT) is widely used in the engineeringvehicles, military vehicles and other high power vehicles. During HMT power shiftbuffer of its wet clutchs disengaging and engaging can effectively control torque reverseprocess of its fixed displacement hydraulic components, and reduce impact of power shiftto improve its power shift quality.Based on its analysis of oil pressure buffer requirement of HMT wet clutch, theelectrohydraulic proportional buffer was designed, which is consist of the electromagneticproportional valve, buffer valve, keeping pressure valve and other components. Thetheoretical analysis and experimental research of the electromagnetic proportional valvehave been done, and the parameters of the buffer value and pressure keeping value havebeen designed. Through the static buffer characteristics analysis, their influence factorshave been determined. The simulation model of the electrohydraulic proportional bufferwas established, included models of the electromagnetic proportional valve, buffer valve,e keeping pressure valve and wet clutch, etc. The paper carried out a simulation analysison the oil charging and discharging process of HMT wet clutch, which showed that itsdynamics characteristics can meet the requirements of HMT wet clutch. The structure andcharacteristics parameters of electrohydraulic proportional buffer on buffer characteristicswere also analyzed by simulation in which the overlap of keeping pressure valve, thestiffness of its spring, the area of the end face of buffer valve and other parameters onbuffer characteristics rules were obtained.