先导腔动压反馈比例溢流阀设计与性能分析

Performance Analysis of Proportional Relief Valve with Dynamic Pressure Feedback Pilot Chamber

普通比例溢流阀在高压、大流量工作时,其调压偏差大、压力波动大,同时会引起调压弹簧疲劳,产生振动和噪声,降低了使用寿命及可靠性。针对以上问题,基于G型π桥液阻网络原理,设计了一种先导腔动压反馈电液比例溢流阀,提出采用液压刚度(活塞式)替代先导阀弹簧刚度的设计方法,以提升先导阀芯响应速度和整体稳定性。对溢流阀进行了结构设计、原理分析、数学建模及仿真分析,并根据优化后的结构参数进行设计和实验验证。结果表明,该溢流阀高压时调压偏差低,在压力26.25 MPa时比普通阀降低了72%,最低为0.53 MPa;动态特性良好,超调最低为0.94%,阀芯振动减小,工作平稳。将溢流阀用于ZL50G型装载机上,代替原有的动臂油路上溢流阀和背压用电磁溢流阀,分析了空载状态下溢流阀对工作装置动作的影响,仿真分析结果表明,溢流阀压力波动降低了70%,系统工作稳定性得到提高。

The traditional proportional relief valve shows great pressure fluctuation and pressure deviation because the regulating spring stiffness is not enough under high pressure or large flow conditions,which makes the pressure regulating spring easy to fatigue and increase vibration and noise,it can reduce its life and reliability.The electro-hydraulic proportional relief valve with dynamic pressure feedback pilot chamber was studied based on G-typeπbridge hydraulic resistance network,and the design method of hydraulic stiffness instead of spring stiffness of pilot valve was proposed,so it can improve response speed of the pilot valve core and stability to reduce pressure fluctuation and pressure deviation and there was no spring fatigue.Further structure and principle,theoretical modeling and simulation analysis of the new relief valve were carried out,the prototype was machined according to the optimized structure parameters and the dynamic and static characteristic of the new valve was verified by experiments.The results showed that the pressure deviation of the new relief valve was low under high pressure condition,especially it was 72%lower than that of traditional proportional relief valve and the minimum was 0.53 MPa when the inlet pressure was 26.25 MPa.In addition,it had good dynamic characteristics,the minimum pressure overshoot was 0.94%,and the spool vibration was decreased and worked smoothly.Finally,the relief valve was used in ZL50G loader to replace the relief valve and back pressure solenoid valve on the original moving arm oil circuit,and the influence of the relief valve on the operation of the working device under no-load condition was analyzed.The pressure fluctuation of the relief valve was reduced by 70%and the vibration and noise of the system were reduced.