共查询到19条相似文献,搜索用时 171 毫秒
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邱兆玲 《机电产品开发与创新》2018,(6):69-72
在简述电液比例节流阀基本原理的基础上,分析了库仑摩擦力对主阀阀芯的干扰作用,通过叠加颤振信号的方法消除了库仑摩擦力对主阀阀芯的影响;建立了主阀阀芯在稳态、暂态以及叠加颤振信号三种不同状态的数学模型以及三者之间的相互关系,并进行了受力分析;给出了需要根据输入信号大小不断调整颤振信号幅值及频率的原因;根据建立的比例节流阀的动态信号特性框图,进行了阶跃响应和正弦波响应的时域分析及Matlab/Simulink仿真。Simulink仿真显示,主阀阀芯叠加颤振信号有利于消除库仑摩擦力引起的滞环、流量死区及动态特性的不稳定因素,能够提高主阀阀芯的稳态特性和动态特性。 相似文献
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针对2D电液比例换向阀阀芯卡滞现象,应用缝隙流动原理,对2D阀芯有无偏心情况下的径向卡紧力进行系统理论分析,得到2D阀芯液压卡紧力计算方法;运用MATLAB软件进行数值计算,得出2D阀芯径向卡紧力与偏心量和高低压孔夹角间的关系;根据2D阀特性,提出2D电液比例换向阀阀芯改进措施,应用Fluent 软件对阀芯表面的流场进行CFD仿真分析,比较了改进前后的流速矢量和压力分布情况,验证了改进措施的正确性。改进后的2D电液比例换向阀在中高压实验中无“卡滞”现象出现,实现了高压大流量的比例控制。 相似文献
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适用于液压支架的比例方向阀代替现有的开关型方向阀,是液压支架智能化的重要组成部分。提出了一款适用于液压支架系统的比例方向阀方案,其兼有手动开关控制模式和电液比例控制模式,建立了其数学模型和仿真模型,分析了其动静态特性。研究表明:主阀进液阀芯位移与输入信号占空比呈线性反比例关系;合理设计反馈槽宽度和进液阀芯面积比可以提高阀芯的响应速度;当仅有液压反馈时,进液阀芯位移仍受控于输入信号,避免了因传感器失效对控制系统造成的灾难性事故的发生;通过增加电反馈与原有液压反馈构成双反馈控制的方式,大幅提高了阀的响应速度、线性度、滞环等特性。 相似文献
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为了提高液压支架的机械控制能力,利用电液换向阀完成支架控制箱动作控制。该文采用流体动力学仿真了电液换向阀的动态特征及流场特性。研究结果表明:当时间到达0.14 s时二级阀芯发生运动,出口流量快速增大至一个峰值状态;随着阀芯到达一个稳定运动状态后,换向阀也达到1013 L/min的稳定出口流量。换向阀在高压大流量系统内工作时将会快速到达峰值压力,产生液压冲击作用并使支架立柱受到破坏。当流体由阀套流至阀芯时因为过流断面的面积会迅速降低,使压力下降4.1 MPa,形成压力集中损失的区域,同时在阀芯的主流道区域还会形成均匀的压力分布状态。从阀口的下游最初进入阀芯的主通道位置时将达到最大流速,等于109 m/s,表明该部位形成了最小的过流面积。 相似文献
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针对液压支架电液换向阀在使用中频繁出现的阀芯断裂及复位弹簧失效问题,利用AMESim仿真分析软件对不同机械限位距离及不同阻尼孔内径情况下阀芯开启时的动态特性的研究,根据分析结果提出了合理配置阀芯动作行程来降低换向时震动冲击的方案,以降低阀芯换向时的冲击力,提高阀芯的使用寿命和液压支架工作时的可靠性。 相似文献
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该文分析了液压支架用手动先导阀的工作原理和结构,并在AMESim平台上建立了手动先导阀模型并进行了仿真,重点分析了其动态特性和主控阀阀芯上的阻尼孔大小变化对阀芯运动的影响,得出主阀芯的位移、流量和速度响应曲线。结果表明,主控阀阀芯的阻尼孔变化对阀芯速度及开启时间影响很大,为合理设计主阀阀芯阻尼孔提供了一定理论依据。 相似文献
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以长江船闸液压启闭机液压系统为对象进行研究,利用AMESim软件搭建该液压启闭机液压平衡回路仿真模型,并对整个船闸开启过程和关闭过程中插装式平衡阀内主阀芯弹簧刚度等主要参数进行单因素仿真。利用统计学分析这些单因素参数对长江船闸液压启闭机液压系统稳定性的影响。基于L25(54)正交试验,采用方差和极差分析法处理液压缸运行的压力曲线,得到选择范围内最佳的参数组合。结果表明:平衡阀内控制阻尼孔和主阀芯刚度等主要参数对液压缸运行压力和速度平稳性会产生重要影响,且通过正交试验可知较优参数组合为:阻尼孔尺寸0.71 mm,主阀芯弹簧刚度402 N/mm,主阀芯弹簧预紧力60 N,单向阀芯弹簧刚度3.87 N/mm。为螺纹插装式平衡阀的设计及液压启闭机液压系统参数优化提供指导。 相似文献
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To solve the problems of large volume, and low integration of traditional electro-hydraulic servo valve with constant pressure differential fuel metering device, a new two-dimensional three-way constant pressure differential fuel flow control servo valve (2D3WFFCSV) is developed. It innovatively adopts the advantages of lightweight of “two-dimensional hydraulic technology”, The constant differential pressure function and flow regulation function are integrated into a two-dimensional (2D) main spool with two degrees of freedom (rotational and axial degrees of freedom). The flow control process of 2D3WFFCSV is as follows: firstly, the armature of the torque motor and the two-dimensional piston are coaxially installed at the end of the two-dimensional piston, so the torque motor can directly drive the two-dimensional piston to rotate; secondly the “hydraulic servo screw mechanism”, which can amplify the power, is used to drive the two-dimensional piston to move in line; Finally, a pair of conversion mechanisms (roller group and spiral track conversion mechanism) are converted into the angular displacement of 2D main spool to control the area of flow valve port. The axial degree of freedom of 2D main spool realizes the function of constant differential pressure. To improve the flow control accuracy of the servo valve, the axial position of the 2D piston is detected by the linear displacement sensor (LVDT), and the signal is transmitted to the controller to realize the closed-loop control. To explore its open-loop characteristics, the mathematical models of torque motor, two-dimensional piston and main spool are established to obtain its open-loop transfer function. Then the AMESIM simulation model is built. To optimize the design of the system, through the dynamic simulation of the system, the influence of key parameters on the dynamic response of the system can be studied. An experimental study is carried out to verify the design feasibility of the servo valve. The experimental results show that under the condition of no-load and full-scale input, the closed-loop delay of the servo valve is 1.84%, the linearity is 2.14%, the step response time is 43 ms, and the dynamic frequency response is 38 Hz. The newly developed 2D3WFFCSV has the advantages of high integration, small size, light weight (801.5 g) and high response and control accuracy. It can replace the constant differential pressure, metering valve and hydraulic servo valve in the aeroengine fuel regulator. 相似文献
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Maher Yahya Salloom Zahurin Samad 《The International Journal of Advanced Manufacturing Technology》2012,58(1-4):279-292
The main part in hydraulic system is directional control valve. Directional control valve has complex construction such as moving spool to control the direction of actuator for required speed. Magneto-rheological (MR) fluid is one of controllable fluids. Utilizing the MR fluid properties, direct interface can be realized between magnetic field and fluid power without the need for moving parts like spool in directional control valves. This study proposes the design of four ways/three position MR proportional directional control valve (4/3 MR valve). The construction of valve and the principle of work are presented. Analysis for magnetic circuit and simulation for valve performance were done. The experiment was conducted to show the principle work of the valve functionally. Design and finite elements analysis using FEMM software of the MR valves were done to reach the optimal design. The valve works proportionally to control the direction and speed of hydraulic actuators. As the result, the optimal design of the valve achieved the optimum performance. The experimental result demonstrates the operation of 4/3 MR valve in 12 configurations. The 4/3 MR valve can replace many types of the spool directional control valve for controlling hydraulic actuator. 相似文献
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在挖掘机器人运动控制中,控制元件比例阀在零位存在较大的死区,驱动元件非对称液压缸为非线性系统,使得对铲斗关节实现高性能位置伺服控制难度很大.提出一种基于局部线性化模型的时延鲁棒控制方法;考虑到编码器测量精度较低,对液压缸位移及速率信号提出一种在线鲁棒估计方法,通过对扰动输入的补偿来减小估计误差;提出一种新型的比例阀死区补偿策略,依据参考模型位置输出对比例阀零位进行切换,既不牺牲系统的动态品质,又能有效避免比例阀阀芯的频繁切换.计算机仿真结果表明,这一方法对外部力扰动和参数变化均具有很强的鲁棒性,且新型速率观测器和比例阀死区补偿环节能明显增强液压系统输出的平稳性. 相似文献
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为了研究电比例斜盘式恒压柱塞泵的动静态特性,在分析其工作原理、运动特性和流量特性的基础上,利用SimulationX软件搭建恒压泵的机械、液压联合仿真模型进行研究,分析了变量缸大小腔直径比、变量缸弹簧刚度和主控压力阀的阀芯直径对恒压泵动态特性的影响。研究结果表明:电比例斜盘式恒压柱塞泵泵具有良好的动静态特性;主控压力阀阀芯直径越大,压力稳态值越接近设定压力值;弹簧刚度的增大和变量缸大小腔直径比值的减小都会提高恒压泵的动态响应速度,但超调量也会随之增大。 相似文献
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In this article, a method aims at reducing the steady-state axial flow force working on the main spool of a diverged flow cartridge proportional valve was proposed. The maximum flow force of original main spool can reach as high as 24% of the control force, which will definitely cause a huge disturbance to the proportional control of main spool, and consequently, the work condition of valve will be in an unstable status. The main contents of this paper are as follows: first, describing the damping flange and its parameters which may influence the effect of compensation; second, the rule that how these parameters influence the flow force was found by a series of computational fluid dynamics (CFD) simulations, and then, according to the analysis, the optimal structure can be gained, besides, the effect of damping flange on pressure difference is also taken into account; at last, a test-bed was built up to validate simulative results. The experiment results shows that the result of simulation is reliable and the proposed methods is feasible. 相似文献
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插装式比例阀具有低泄漏、通流能力强、结构简单等优点,广泛应用于液压系统中,但插装阀所带来的振动及噪声等问题是制约其使用范围的重要因素。对采用流量放大原理的Valvistor型插装阀稳定性及性能进行研究,建立相应的数学模型得出该阀的稳定性条件,发现主阀稳定性与先导阀开口及面积增益有关;在SmiluationX软件环境中建立该阀的仿真模型,并利用实验对其进行验证。理论分析与仿真结果表明:随着主阀进出口压差、反馈窄槽面积梯度的增大,主阀芯响应速度加快,但会导致主阀芯不稳定区域增加;控制腔体积越小,主阀芯稳定性越好。研究结果为该类型阀性能的提高提供了理论依据。 相似文献