油液温度对液压缓冲阀动力学特性影响分析

Analysis of Influence of Oil Temperature on Dynamic Characteristics of Hydraulic Buffer Valve

油温对重型车辆机械控制式液压缓冲阀的运动部件动力学特性及出口压力调节过程均会产生显著影响。依据某重型车辆液压缓冲阀,建立阀芯及缓冲活塞的动力学模型,通过流场仿真对阀芯过流面积、流量系数及射流角进行详细解析,最后在20~100℃油温下对换挡缓冲液压系统进行仿真分析和实验对比研究,从而揭示了油温对缓冲阀运动部件及调压过程的作用机理。研究表明,随着温度升高:缓冲阀入口流量系数小幅增大,入口射流角及阀芯黏性摩擦力先增大后减小;阀芯和活塞运动速度增大;100℃时的压力调节时间较20℃时缩短36%,缩短幅值大;缓冲结束时,对稳定输出的压力影响不大;缓冲阀在缓冲升压阶段的起止压力不会因油液温度变化产生较大变化。

For the mechanically controlled hydraulic buffer valve of heavy vehicles,the oil temperature has a significant influence on the dynamic characteristics of its moving parts and the adjustment process of outlet pressure.Based on the hydraulic buffer valve of a heavy vehicle,the dynamic model of the valve spool and buffer piston is established.Through flow field simulation,the flow area,flow coefficient and jet Angle of the valve spool are analyzed in detail.Finally,the simulation analysis and experimental comparative study of the shifting buffer hydraulic system are carried out under the oil temperature of 20~100℃.The effect mechanism of oil temperature on moving parts of buffer valve and pressure regulation process was revealed.Research shows that With the increase of temperature:the flow coefficient at the inlet of buffer valve increases slightly,The inlet jet Angle and the viscous friction of valve core first increases and then decreases;The spool and piston speed increase;The pressure adjustment time at 100℃is 36%shorter than that at 20℃,the shortening amplitude is large;At the end of buffering,there is little effect on the stable output pressure;The starting and ending pressure of the buffer valve will not change greatly due to the oil temperature change.