Numerical Simulation and Experimental Study of Heat-fluid-solid Coupling of Double Flapper-nozzle Servo Valve

The double flapper-nozzle servo valve is widely used to launch and guide the equipment. Due to the large instantaneous flow rate of servo valve working under specific operating conditions, the temperature of servo valve would reach 120℃ and the valve core and valve sleeve deform in a short amount of time. So the control precision of servo valve significantly decreases and the clamping stagnation phenomenon of valve core appears. In order to solve the problem of degraded control accuracy and clamping stagnation of servo valve under large temperature difference circumstance, the numerical simulation of heat-fluid-solid coupling by using finite element method is done. The simulation result shows that zero position leakage of servo valve is basically impacted by oil temperature and change of fit clearance. The clamping stagnation is caused by warpage-deformation and fit clearance reduction of the valve core and valve sleeve. The distribution roles of the temperature and thermal-deformation of shell, valve core and valve sleeve and the pressure, velocity and temperature field of flow channel are also analyzed. Zero position leakage and electromagnet＇s current when valve core moves in full-stroke are tested using Electro-hydraulic Servo-valve Characteristic Test-bed of an aerospace sciences and technology corporation. The experimental results show that the change law of experimental current at different oil temperatures is roughly identical to simulation current. The current curve of the electromagnet is smooth when oil temperature is below 80℃, but the amplitude of current significantly increases and the hairy appears when oil temperature is above 80℃. The current becomes smooth again after the warped valve core and valve sleeve are reground. It indicates that clamping stagnation is caused by warpage-deformation and fit clearance reduction of valve core and valve sleeve. This paper simulates and tests the heat-fluid-solid coupling of double flapper-nozzle servo valve, and the obtained results provide the reference value for the design of double flapper-nozzle force feedback servo valve.

Static Characteristics of the New Type Nozzle Flapper Amplifier for Double Nozzle Flapper Electro-Hydraulic Servo Valve

A new type nozzle flapper amplifier for double nozzle flapper electro-hydraulic servo valve is proposed in the paper.The electro-mechanical converter of new type nozzle flapper amplifier is designed by using the piezoelectric bimorph and beryllium-bronze materials.The structure and working principle of the new type nozzle flapper amplifier are introduced.Pressure characteristic and flowrate characteristic are analyzed by experimental method.The research results show that pressure characteristic has large amplification factor and output pressure;flowrate characteristic has large linear range and output flowrate.

双喷嘴挡板刹车控制阀参数敏感度研究

基于某型民用客机刹车系统架构,介绍了国内某型民用飞机刹车系统所配套的刹车控制阀的结构及工作原理,通过AMESim软件建立基于结构化的模型,仿真分析关键参数,如负载容积、弹簧预紧力、滑阀遮盖量、喷嘴前置级阻尼孔孔径、喷嘴孔径、回油路阻尼孔孔径、喷嘴挡板间隙、弹簧管弹性模量、弹簧管壁厚及磁间隙等对刹车控制阀输出特性的敏感度,辅助产品正向设计,指导产品装配调试,帮助定位产品故障原因,提高产品的性能稳定性及可靠性。

两级电液伺服阀双喷嘴挡板阀内流场计算与分析

双喷嘴挡板阀是两级电液伺服阀的前置级,其结构参数对电液伺服阀的性能有着重要的影响。利用流场计算软件,对双喷嘴挡板阀的喷嘴在不同结构参数组合下的流场进行了计算,并分析了其液流特性,如速度特性、压力特性、流量特性等。研究表明:通过喷嘴挡板阀的流量随喷嘴直径、喷嘴端面直径和喷嘴外夹角的增大而增加,喷嘴挡板阀的压差却相应地减小;而喷嘴长度、喷嘴内夹角和腔内径对喷嘴各项性能影响不大。通过比较分析找到最佳结构参数组合,为双喷嘴挡板电液伺服阀喷嘴的工程设计提供理论依据和参考。

双喷嘴挡板伺服阀弹簧管刚度对伺服系统的影响分析

对双喷嘴挡板伺服阀进行全面建模,分别从力矩马达、衔铁挡板组件、滑阀3个部件进行数学建模。力矩马达数学建模考虑了永磁体漏磁、导磁元件磁阻、永磁体磁阻及工作气隙因素;衔铁挡板组件模型考虑了其平动和转动两个自由度;而滑阀的数学建模采用常规建模方式。同时引入其他模型与所建立的模型通过AMESim仿真进行对比分析,并且逐步分析了弹簧管刚度对位置伺服系统和变幅伺服系统的影响。

喷嘴挡板伺服阀力矩马达振动特性的谐响应分析

针对伺服阀自激噪声产生机理的问题,对伺服阀力矩马达的振动特性进行了研究,给出了一种双喷嘴挡板伺服阀力矩马达的结构及工作原理。基于结构力学基本原理,建立了该双喷嘴挡板伺服阀力矩马达衔铁挡板组件的振动特性有限元分析数学模型;采用有限元分析方法,对伺服阀力矩马达衔铁挡板组件进行了模态分析,计算了前7阶振型下衔铁挡板组件的固有频率,并通过谐响应分析得到了衔铁挡板组件在电磁力作用下的响应曲线。研究结果表明:衔铁和反馈杆是伺服阀力矩马达产生振动的关键部位,其在工作平面内的振动对伺服阀的工作性能影响最大,同时衔铁挡板组件的谐振峰值主要集中在低频范围内;通过谐响应分析给出了一种计算谐振振幅的方法,为伺服阀的性能改善及结构的优化提供了理论参考。

双喷嘴挡板力反馈伺服阀的阀芯振荡分析

基于双喷嘴挡板力反馈伺服阀的结构特点,根据伺服阀内部的压力-流量方程、阀芯运动学方程,首次建立了伺服阀阀芯振动的数学模型,推导了伺服阀固有频率及幅值放大系数的数学表达式;并以国产某型号伺服阀为例进行了理论分析,研究了阀芯质量、反馈杆刚度对于伺服阀固有频率及幅值放大系数的影响。结果表明:固有频率随阀芯质量的增加、弹簧杆刚度的降低而依次降低;幅值放大系数随阀芯质量、载荷频率、弹簧杆刚度的增加而依次降低。本文研究为双喷嘴挡板力反馈伺服阀的设计提供了理论基础。

电液伺服阀污染磨损加速退化试验设计

以双喷嘴挡板式电液伺服阀为研究对象,分别对电液伺服阀磨损机制与Omega寿命理论进行了分析,并针对该试验设计了电液伺服阀污染磨损试验系统。通过对电液伺服阀进行预试验,确定试验的敏感应力为油液的污染度,试验的性能退化参数为压力增益与内泄漏量。通过对预试验结果进行分析,得出试验的应力水平、应力施加方式和压力增益与内泄漏量两个性能退化参数的退化模型。结合以上分析结果,最终给出了电液伺服阀污染磨损步进应力加速退化试验的试验方法。该方法的提出可有效的缩短试验时间,为电液伺服阀安全、可靠运行提供保障,并对提高电液伺服阀可靠性,完善其性能具有一定的指导意义。

双喷嘴挡板电液伺服阀前置级流固耦合分析

分析双喷嘴挡板电液伺服阀前置级的动态流场,研究衔铁挡板组件受力发生偏转导致前置级流场发生变化,分析固定节流口、喷嘴、回油口处的流速、压力变化和功率损失,以及衔铁挡板组件、滑阀阀芯的位移及受力情况。该研究利用ANSYS软件,采用流固耦合分析方法对双喷嘴挡板电液伺服阀衔铁挡板组件及前置级流场进行分析,为双喷嘴挡板电液伺服阀的流场分析提供了一种更接近实际的分析方法,得到更为精确的分析结果,为模型结构参数及固体材料的选择提供一定的指导。

炼钢厂液压系统电液伺服阀的选用与日常维护

介绍了当前电液伺服阀的种类与结构特点,针对炼钢厂液压系统电液伺服阀在不同工作环境的选用情况进行探讨分析,结合实际应用经验,提出了电液伺服阀日常点检维护的要点。

SFF-10电液伺服阀的设计

以某型号电液伺服阀为参照,设计了SFF-10电液伺服阀。叙述了SFF-10电液伺服阀的作用、组成以及工作原理;通过对比分析电液伺服阀的几种类型,确定了双喷嘴挡板式电液伺服阀设计方案、采用Excel软件对电液伺服阀的阀套与阀芯、喷嘴组件以及衔铁组件进行了设计计算。通过建模仿真验证了本设计满足设计要求。

热轧卷取AJC伺服系统故障的快速诊断

八钢热轧卷取机采用全液压AJC伺服系统控制卷取全过程,由于机电液一体化控制高度集成,内部结构复杂,一旦出现故障,排查较为困难。文章介绍了利用IB实时在线监测系统,分析了几种常见AJC伺服系统故障原因及其有规律的曲线图,帮助现场快速诊断故障原因,从而快速消除故障。

三级喷嘴挡板伺服阀喷嘴堵塞故障分析

为排除三级喷嘴挡板伺服阀的故障,对其结构组成和工作原理进行了分析,该阀由两级先导阀及主阀构成。两级先导阀,第一级为喷嘴挡板结构,固定节流孔和喷嘴挡板可变节流孔构成了一个液压全桥;第二、三级为滑阀结构。通过对故障阀进行空载流量测试发现,先导阀流量输出异常和三级伺服阀阀芯位移反馈不变。据此判断,伺服阀先导级可能存在卡阻,破坏了液压全桥的正常工作。对伺服阀拆解后发现,喷嘴挡板机构部分堵塞。对该阀进行清洗后重新组装,检测空载流量、滞环等指标,均在控制范围内,故障排除。