【作者】 洪威；

【导师】 刘桓龙；

【作者基本信息】 西南交通大学 ， 机械电子工程， 2013， 硕士

【摘要】 溢流阀是液压系统中非常重要的元件,几乎应用于每一个液压系统中,其主要作用是通过溢流来限定液压系统的压力为一恒定值或者防止液压系统过载。溢流阀的工作特性对液压系统或回路有重大的影响,因此对其进行研究有重要的意义。本文详细地阐述了溢流阀的发展历程、国内外研究现状及目前研究存在的关键问题。介绍了美国SUN Hydraulics公司生产的RPET型号的溢流阀,描述了该溢流阀的构成及其实现动态无压力超调的工作原理,并以该型溢流阀为对象进行本文无压力超调溢流阀的研究。论文主要包括5个方面的内容：(1)根据课题的要求,无压力超调溢流阀的额定流量为50L/min,额定压力为16MPa,按此要求,对溢流阀进行设计计算,初步确定各主要结构尺寸；(2)在AMESim中建立溢流阀的动态仿真模型,分析溢流阀各结构参数如阻尼孔直径、各敏感腔体积、弹簧刚度、阀座孔直径等对其动态性能的影响,并优化结构尺寸；(3)对溢流阀进行理论分析,建立其静态数学方程,并在某一稳定点进行线性化,分析对溢流阀静态性能有较大影响的因素,然后在AMESim中仿真溢流阀在不同流量下的稳定压力,得出相关参数对溢流阀压力—流量特性的影响,并计算其开启比；(4)针对RPET型溢流阀存在调压偏差大,开启比小的缺点,分析其产生的原因主要是溢流阀阻尼孔布局结构和主阀芯的稳态液动力,从这两点出发对溢流阀进行结构方面的改进。对于阻尼孔结构,改进RPET型溢流阀的两阻尼孔布局结构为三阻尼孔布局结构,并由理论计算分析和AMESim仿真得出,相比于两阻尼孔结构,三阻尼孔结构不仅具有良好的动态性能,能实现无压力超调,而且其调压偏差小、开启比大；对于主阀芯稳态液动力,通过在主阀芯上增加突缘结构来实现稳态液动力补偿,并通过理论分析和CFD仿真进行证明；(5)分析得出影响溢流阀升压时间的参数,并采用正交试验法,利用AMESim软件进行仿真优化。更多还原

【Abstract】 Pressure relief valve is a very important component,which is used in almost every hydraulic system,it’s mainly used to limit the system’s pressure to a constant value or prevent hydraulic system overloading.The performance quality of the relief valve has a great influence on the entire hydraulic system and therefore it’s significant to study the relief valve.This paper elaborates the development of the relief valve,and it’s research status at home and abroad,and the key issues in present study.Introduce the RPET type relief valve,which is produced by the SUN Hydraulics corporation of the United States,describe the composition of the relief valve and it’s working principle of realizing the dynamic response process without pressure overshoot,and study the characteristics of the relief valve without pressure overshoot in this paper by making the RPET type relief valve as an object.This paper includes four parts:(1)According to the requirements of the project,the rated flow of relief valve without pressure overshoot is50L/min,and it’s rated pressure is16MPa.Then,according to this requirement,design and calculate the relief valve,preliminary obtain major dimensions;(2)Build dynamic model of the relief valve in AMESim software,simulate and analyze the effects of structural parameters such as orifice diameter,sensitive cavity volume,the stiffness of spring and seat hole diameter,etc on relief valve’s dynamic characteristics,and then optimize the related structural parameters;(3)Theoretically analyze the relief valve.Establish the relief valve’s static mathematical equations,and then linearize the equations at a steady-state point of the relief valve,analyze the linearization equations and achieve the factors which have great impact on the relief valve’s static properties,simulate the relief valve’s stable pressure under different flow rate by using AMESim,and obtain the effects of related parameters on relief valve’s pressure-flow rate characteristics,then calculate the relief valve’s unlock ratio;(4) For RPET type relief valve existing the disadvantages of larger pressure regulator deviation and smaller unlock ratio,analyze the main reasons are the orifices’layout of the relief valve and the steady-state flow force of the main poppet valve,then,improve the structure of the relief valve according to these two points.For the layout of damping holes,change the RPET type relief valve’s two-damping holes’layout structure to the three-damping holes’layout structure,through theoretical analysis and AMESim simulation,the relief valve with three-orifice layout structure is proved better dynamic properties,which can realize zero pressure overshoot during dynamic process,and has smaller pressure regulator deviation and larger unlock ratio; for the steady-state flow force of the main poppet valve,compensate the flow force by adding flange structure to the main valve,and the rationality of the new structure is verified by theoretical analysis and CFD simulation;(5)Analyze the factors that have influence on the pressure rise time,then optimize them by using orthogonal tests and AMESim simulation.更多还原