Research On Buffer Characteristics And Multi-objective Optimization Of Vehicle Shift Buffer Valve

Due to the incompressibility,the stiffness of t2e oil will cause a shift shock phenomenon,especially the working environment of the heavy vehicle is more severe,and the impact will reach more than several times over the maximum calculated torque.Actually the shifting process is to control the combination and separation of two different gear clutches,while if you can control the rise of the oil pressure in the clutch reasonable,that you can reduce the dynamic load on the output shaft,the impact and improve the shifting quality effectively,so,it is extremely necessary to design a satisfactory buffer valve.In this paper,a buffer valve is studied in the AMESim environment for modeling analysis,optimization design and verification of the results.The main contents including:Analyze the working principle of the buffer valve,build the simulation model and analyze the buffer characteristics under four different structural parameters,It is concluded that as the increase of the spring preload force and the displacement of the spool restricts,the buffer time will increase.The magnitude of the spring stiffness affects not only the buffer time,but also the buffer speed,with the increase of spring stiffness,the rise rate of the outlet pressure will up but the buffering time becomes longer;the outcome of the orifice diameter become bigger is shorten the buffering time gradually,and influence the pressure at the beginning and end of the buffering boosting phase,which increases with increasing diameter.Because of the analysis of simulation and buffer characteristics,on the ideal cushioning characteristic curve,the DOE(Design of experiment)test design method is used to analyze the structural parameters of the valve:spring preload,spring stiffness,orifice stud,piston diameter,piston rod diameter and spool limit displacement have biggest influence on the oil pressure characteristics;and according to the result,the genetic algorithm is applied to the desired curve to optimize the optimal value.The optimal curve is compared with the ideal curve.The buffer time is 1.4s,no overshoot,the curve is more consistent,the buffering effect is ideal.Based on the above,the result is correct that the experimental analysis of the characteristic analysis shows that the variation trend of the test curve under different spring preload and orifice diameter is consistent with the trend of the simulation curve for verify the correctness of the characteristic analysis and optimization,the buffering time increases with the preload and diameter.Using the oretical methods to verify optimal design,and the formula of the buffer time t is derived.The buffer time before calculation and optimization is 3.3 s and the comparison time of the valve test is 3.5s,so the formula is correct,and by the compared between formula and the DOE result to know that the formula is correct.On this formula,the buffer time of the optimal structure is 1.5s,the optimization result simulation time is 1.4s,this optimization method is correct.