带定压活门的液压阻尼器建模因素分析

摘要

针对现有带定压活门的液压阻尼器模型考虑因素不同、形式不统一等问题,通过分析油液含气和压缩性、阀口液动力、阀口流量系数和等效面积、串油管路阻力和管路部分油液压缩性等因素对液压阻尼器等效阻尼及阻尼力峰值的影响,建立了液压阻尼器定压活门内置与外按时统一的力学模型.将某型带定压活门的液压阻尼器在1、9、26 mm共3种不同激振幅值下等效阻尼及阻尼力峰值的计算结果与实验值进行对比,结果显示,等效阻尼误差分别为-9.994 5％、0.672 4％和-2.757 2％,阻尼力峰值误差分别为-0.457 4％、1.973 3％和-4.074 9％,该结果验证了所建力学模型的准确性.在进行影响因素分析时发现,油液体积弹性模量在低压时对含气量较为敏感,随着含气量的增加急速下降,弹性模量的改变对等效阻尼和阻尼力峰值均有较大影响,特别是在激振幅值较小的情况下表现更明显;阀口液动力对定压活门开启后的阻尼力峰值影响较大,而对等效阻尼的影响较小;阀口流量系数取常量且阀口等效面积简化成阀芯位移的一次函数后对等效阻尼及阻尼力峰值基本没有影响;定压活门外接时,串油管路阻力和管路部分油液压缩性对等效阻尼和阻尼力峰值的影响都不大.%Aimed at the problem that the existing models of hydraulic damper with pressure relief valve consider different factors and have different forms,a unified dynamic model was presented for hydraulic damper with pressure relief valve internal and external by analyzing the effects of oil mixed with gas and oil compressibility,valve port dynamic flow force,valve port discharge coefficient and equivalent area,and string pipeline resistance on equivalent damping and damping force peak.The theoretical results of equivalent damping and damping force peak were compared with the test data while some hydraulic damper with 1,9 and 26 mm excitation amplitude.The results showed that the errors of equivalent damping are-9.994 5％,0.672 4％ and-2.757 2％,respectively,and the errors of damping force peak respectively are-0.457 4％,1.973 3％ and-4.074 9％.The model accuracy has been validated by the results of errors.Furthermore,the analysis results of influence factors showed that oil elastic modulus is sensitive to air percentage in low pressure,it descends rapidly with air percentage increasing,and oil elastic modulus has great influence on equivalent damping and damping force peak,especially with small excitation amplitude.Valve port dynamic flow force has large effect on damping force peak while pressure relief valve opening,but has little effect on equivalent damping.The simplification of valve port discharge coefficient and equivalent area almost have no influence on equivalent damping and damping force peak and the pipeline resistance and oil compressibility of pipeline have slight influence on equivalent damping and damping force peak.