全液压压裂车大流量换向阀的设计与分析

为满足全液压压裂车液压系统液压缸的换向需求,设计了大流量换向阀组,重点设计了阀芯、阀套组件;分析了大流量换向阀的原理与结构,建立了其数学模型,基于AMESim软件分析了主阀的开启时间,阀芯位移、速度与先导流量和先导压力的关系,结果表明:适当增大先导压力和先导流量可提高主阀的响应特性;改变主阀端面结构、适当增大先导压力和减小先导流量可解决主阀瞬时流量过大的问题。设计与仿真相结合,缩短了主阀的设计时间,为阀的设计计算提供了参考价值。     

具有对称不均等正开口量液压滑阀压力特性研究

一、引言文献1分析了对称液压阀控不对称液压缸伺服系统存在的失控,气蚀及液压缸换向压力突变现象,提出了采用新型不对称液压阀控不对称液压缸,实现液压元件之间的流量匹配与系统协调。本文在文献1的基础上研究了对称不均等正开口量圆柱滑阀的压力特性。液压伺服阀的工作特性取决于阀芯和阀套之间节流工作边及重迭量的制造配合精度。正开口滑阀的阀芯上台肩宽度比阀套上的沟槽宽     

电液换向阀的启动动态特性分析

鉴于方向控制阀作为液压控制系统的重要组成元件,其动态特性对液压系统的稳定性、动态响应、冲击振动等方面均有较大影响,基于AMEsim分析某型电液换向阀的动态特性,发现阀口开度在0.5～2.8 mm(占阀芯行程约6.25％～35.0％)时阀芯产生冲击和振动,进回油口流量在阀芯位移为4mm(占全行程约50.0％)后不再变化.说明控制孔的直径与换向阀二级阀芯的启动响应时间成反相关关系,同时还影响阀芯的振动剧烈程度和恢复稳定时间.     

水液压节流阀精细调节阀口设计与仿真分析

传统水液压节流阀阀口形式多为球阀式和锥阀式,具有良好的阀口密封性,但其存在着流量分辨率低和阀口特性线性度差等缺点。设计了一种新的非全周开口滑阀阀芯,其阀口形式由该非全周开口滑阀阀芯和空心圆柱阀套构成,具有阀芯行程大的特点。该研究进行了CFD仿真分析,结果显示,非全周开口的阀口形式保证了高线性度的阀口特性,阀芯行程的增大提高了阀口的流量分辨率,该阀口形式能够适应水液压传动系统高精度控制的应用需求。     

基于电流调制的电磁开关阀开关特性研究

电磁开关阀是阀控液压系统中重要的基础流控原件，其开关特性决定系统整体性能。传统驱动方式下，阀芯位移响应滞后于励磁驱动电流，阻碍频响的提高。提出通过建立位移反馈提升阀芯在阶跃励磁电流作用下的电磁力的响应特性，进而提升电磁阀位移频响的方法。对二位二通电磁开关阀建立了动力学与电磁学方程，搭建了阀芯电磁-动力学关键参数测量装置。试验验证了试验装置可行性并获得了阀芯位移响应的开环传递函数。结合试验数据，在Simulink中搭建了反馈对电磁开关阀开关特性影响的验证系统。仿真结果表明，通过利用电磁阀位移反馈，阀芯位移对励磁线圈的阶跃响应改善显著，响应时间相比开环阀芯驱动缩短了近53%。     

工程机械液压多路阀阀芯孔精密加工探索研究

液压多路阀是工程机械液压系统的重要元件之一,用来控制液体流动方向、流量大小及压力高低。而液压多路阀阀芯孔加工质量是关键要素,直接影响液压多路阀工作性能及使用寿命。该文首先总结了液压多路阀阀芯孔3种加工工艺方案,然后根据探索及验证,提出了阀芯孔成套化铰孔技术、阀芯孔沉割槽高效加工技术、多冲程珩磨+单冲程珩铰精密加工技术。     

汽车EHB系统动态特性的仿真分析

分析高速开关电磁阀的阀芯运动及其响应特性,建立基于AMESim和Simulink软件的电子液压制动(EHB)系统联合仿真平台。分别改变高速开关电磁阀控制系统的调制频率和占空比,分析其对汽车EHB动态过程的影响,继而得出液压系统液压元件的性能参数及电磁阀控制系统的调制频率选择的要求。最后通过试验验证了EHB系统模型仿真的有效性,为汽车EHB系统的试验研究提供了理论指导。     

先导式换向阀的仿真与试验研究

基于AMESim软件,以常见的两级换向阀为研究载体,重点分析先导阀对主阀阀芯响应及运行特性的影响,建立了该液压系统的仿真模型。在验证模型准确性的基础上,通过仿真对试验进行指导,使主阀阀芯运行更快,冲击小。     

主配压阀响应速度特性仿真研究

该文利用液压仿真软件建立了水轮机调速系统主配压阀响应速度分析模型,并对搭叠量、控制活塞面积、阀芯阀套径向间隙对响应速度的影响进行了仿真研究.结果表明:主配压阀响应速度与搭叠量、控制活塞面积成反比,与阀芯阀套径向间隙成正比.最后指出在保证主配压阀静态特性的前提下,可通过减少搭叠量与控制活塞面积来提高其响应速度.     

基于AMESim的安全阀动态特性优化仿真

液压支架立柱回路中的安全阀,是支架过载保护的关键元件,其性能的好坏,直接影响液压支架的承载能力、工作可靠性。文中在AMESim环境下建立了立柱用安全阀的仿真模型,得出基本顶压时顶板的载荷及顶板的下沉量,并进行仿真,得出了立柱在顶板快速下沉时,安全阀溢流时阀芯的运动曲线和阀口的压力及流量曲线。通过分析仿真结果可知适当增加阀芯的阻尼,可在不影响其响应速度的前提下,减小阀芯的振荡,实现安全阀的动态特性优化。     

新型矿用比例方向阀动态特性及控制方法分析

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。     

新型大流量高水基电液比例换向阀的设计和研究

针对煤矿井下液压支架系统液压冲击大的问题,设计了一款新型大流量高水基电液比例换向阀。介绍了所研制的电液比例换向阀的结构及工作原理,并利用AMESim仿真软件搭建了该阀的仿真模型。研究表明,在斜坡信号输入的情况下,该阀能实现正常换向且主阀口开口大小与输入信号成正比例趋势;在阶跃信号输入的情况下,验证了阀的稳定性并分析了阻尼孔和主阀芯末端锥度对阀性能的影响,发现设置合适的阻尼孔直径有利于提高阀的响应速度,合理选择主阀芯末端锥度大小可以提高阀的稳定性。     

Development of a novel two-dimensional(2D) three-way(3W) fuel flow control servo valve with constant pressure difference

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.     

二维电液比例换向阀动态特性及稳定性分析

二维电液比例换向阀兼具直动式和导控式比例阀的功能:正常工作压力下,比例电磁铁输出的推力通过压扭联轴器使阀芯转动,阀敏感腔的压力差动变化,驱动阀芯轴向移动,与此同时阀芯反向转动,敏感腔的压力又逐渐恢复为原来的值,阀芯到达一个新的平衡位置,实现对阀芯位移的液压先导比例控制;当工作压力为零时,则由比例电磁铁直接驱动阀芯。在正常的工作过程中,压扭联轴器不仅可以实现直线-旋转运动转换,还可将比例电磁铁的驱动力放大,使其能有效、可靠地驱动阀芯转动,从而提高其比例控制性能和工作可靠性。通过2D阀的建模、动态仿真及稳定研究,弄清2D阀的关键结构和工作参数对动态特性的影响,并建立2D阀的稳定条件,为其结构设计和优化提供理论依据。对2D阀试验研究,测得直动与导控两种工作状态下主要性能曲线与指标,试验表明2D电液比例换向阀不仅可以实现直动和导控的功能,而且通过先导控制可以有效克服液动力和摩擦力的不利影响,同时也证明了2D阀具有较快的响应速度和很好的稳定性。     

Analysis of flow torques during opening and closing of high-frequency rotary directional control valve

A 2D high-frequency rotary directional control valve with a spool having two degrees of freedom for axial linear motion and circumferential rotation is proposed in this paper. The axial linear motion decides the maximum orifice area, and the circumferential rotation lets the orifice area change continuously. One of the known elements impacting valve function is the flow force. This paper systematically analyzes the steady and transient flow torques subjected to the valve through theoretical analysis, AMESim-Fluent joint simulation and experimental tests. The results show that: under a single variable, the flow torques of the 2D high-frequency rotary directional control valve initially increase and then decrease like the sinusoid curve with the rotation of the spool and reach the maximum when the orifice opening is 1/2, and the flow torques are always in the direction of orifice closing and want to close the orifice. When the orifice area increases, the flow torques are the resistance, preventing the spool from opening; when the orifice area decreases, the flow torques are the power, pushing the spool to close. The steady flow torques are proportional to the pressure drop. The direction of the transient flow torque is independent of the relative position of the spool groove and sleeve window, which proportional to the square root of the pressure drop, orifice area and rotational speed. The flow torques are so important in the control of valve and can not be negligible.     

插装式2D电液比例流量阀的特性研究

电液控制元件的插装化是目前移动式液压控制系统的主流发展趋势。现有的2D比例阀面向传统工业液压领域,其受到液压桥路以及压扭联轴节结构限制,无法实现插装化。提出一种新型插装式2D电液比例流量阀的结构原理,在电-机械转换器与半桥式2D阀本体之间引入双向滚子联轴节,以此实现力传递、阀芯位置反馈和阀芯直线-旋转运动的转换功能。基于线性理论推导了阀的特性方程,并利用Nyquist判据判定了阀的工作稳定性;为实现优化设计,建立基于AMESim、ADAMS和Matlab/Simulink平台的联合仿真模型,研究诸关键结构参数对动态特性的影响。最后设计并制造了样机,搭建了滚子联轴节和插装式2D阀的试验台架,研究联轴节的静动态特性及阀样机的空载流量特性、负载流量特性、泄漏特性以及频响和阶跃特性等。试验结果表明样机具有良好的工作性能。当预载荷为40 N时,联轴节的最大输出扭矩为2.3 N·m,输出角位移为0.42°,滞环为5.25%,响应时间为32.5 ms;当供油压力为12 MPa时,阀样机的空载流量为61.5 L/min,滞环为6.32%,阶跃时间为68.5 ms,幅频频宽为19.7 Hz,相频频宽为22.1 Hz。研究表明,插装式2D阀具有较好的静动态特性,是移动式电液控制系统流量控制阀的一种较理想解决方案。     

Magneto-rheological directional control valve

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.     

兼顾操纵性与节能性的ECHPS可变助力特性与控制策略

转向系统的助力特性设计与控制对重型车辆的操纵稳定性和节能性具有重要影响。以重型商用车旁通比例阀式电控液压转向系统(Electronically controlled hydraulic power steering system,ECHPS)为研究对象,在Matlab/Simulink中建立包含比例电磁阀子模型、机械系统子模型、液压系统子模型和3自由度整车转向动力学模型的ECHPS系统仿真模型,基于能量流原理分析转向助力特性对转向系统节能性的影响,设计了兼顾操纵性与节能性的ECHPS可变助力特性曲线。采用模糊比例积分微分(Proportional integral derivative, PID)控制策略对比例电磁阀的阀芯位移进行控制,使旁通流量随车速可变。搭建ECHPS性能试验台,对ECHPS在不同车速下的助力特性进行测试,试验结果与仿真设计的理想可变助力特性基本一致,可以实现重型车辆低速时转向轻便性和高速时的良好路感,同时改善了转向系统的节能性。     

Valvistor电液比例流量阀稳定性及特性分析

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。