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%。     

Deadzone compensation control based on detection of micro flow rate in pilot stage of proportional directional valve

The pilot operated proportional directional valves (POPDVs) with a flow rate ranging from 100 to 1000 L/min are widely used in electro-hydraulic systems (EHSs). The deadzone of the pilot stage valve and its control compensation could significantly affect the position control performance for the main stage valve that could directly affect dynamics of EHSs In this paper, it is concluded that micro flow rates exist at the intermediate position of the valve based on the analysis of the continuity equation of the flow in the control chamber of the pilot stage. The micro flow rate is helpful to eliminate the discontinuity and unsmooth domain in the previous inverse deadzone compensation function. An improved deadzone detection method is proposed to calibrate the pilot valve flow characteristics which include the micro flow rate. This new method avoids the threshold selection of the main valve spool displacement which affects the detected deadzone values. Its detection processes are realized based on the pilot flow rate characterized by the speed of the main valve spool and the pilot valve displacement characterized by the solenoid current. The deadzone compensation control strategy based on the improved deadzone detection method is also designed. The experimental results using the steady-state position tracking and sinusoidal position tracking methods are verified. It is concluded that the tracking accuracy of the main valve spool position is effectively improved with this control strategy.     

比例电磁铁在插装电磁阀上的应用

介绍一种新型插装式电磁阀,它采用二级控制,将先导阀和主阀芯集成在一起,组成一个插装件。与传统的插装式电磁阀相比,该电磁阀的电磁铁采用比例电磁铁,根据电磁吸力与弹簧力的平衡调节先导阀的启闭,使主阀芯出口压力保持恒定,应用于小流量恒压控制系统中,做大地提高了液压系统的安全性。     

2D伺服螺旋阀芯大行程位置控制的分析研究

2D伺服螺旋数字阀作为先导控制大流量高频响的换向阀,结构上利用2D阀的阀芯的双自由度运动,阀芯由步进电机驱动旋转,通过高低压孔的开口通断来改变敏感腔的压力,从而推动阀芯轴向运动。大流量高频换向阀的小阀芯与2D阀的阀芯由球头刚性连接,获得所需的大行程,驱动主阀芯运动。基于MATLAB建立2D阀的数学模型,该模型的仿真结果能较为准确地描述2D阀的动静态特征。     

大流量气动高速开关阀的优化设计

针对大流量高速开关阀切换时间长的问题,对高速开关阀流量特性进行了分析,获得了电磁铁工作气隙与阀芯直径的匹配关系;对高速开关阀动作过程进行了分析,建立了开关阀运动耦合瞬态场模型;对电磁铁结构参数进行了Ansoft Maxwell2D仿真,研究了衔铁中心开孔大小、衔铁厚度、绕组匝数对开关阀开启时间的影响。在理论仿真分析的基础上,提出了一种兼顾响应时间的大流量高速开关阀。研究结果表明,经过优化后的开关阀,在进口压力为7 bar时,流量可达720 L/min,而切换时间仅为9.5 ms。     

一种高压大流量插装式先导型溢流阀的仿真分析与优化设计

针对一种高压大流量插装式先导型溢流阀展开仿真分析与优化设计。首先对溢流阀主要结构参数进行初步设计计算;然后根据溢流阀内部结构建立AMESim仿真模型并进行仿真,对主阀阻尼孔、先导阀阻尼孔、主阀弹簧刚度、主阀弹簧预紧力、先导阀弹簧刚度、先导阀弹簧预紧力等重要参数进行特性影响分析;最后根据仿真分析结果,采用响应曲面与非支配排序遗传算法相结合的方法,求解一定范围内溢流阀最优结构参数,实现溢流阀满足高压大流量指标且调压偏差尽量小的要求。     

ABS高速开关阀液压力影响因素研究

高频小流量高速开关阀用于汽车防抱死制动系统 (ABS)增压与减压的控制,在不同温度环境下,其可靠的动态特性是ABS正常工作的重要指标。高速开关阀阀芯高频运动过程中,主要受到电磁力、液压力等因素的影响。针对液压力,建立高速开关阀不同温度、阀口两端压差、阀口开度的有限元仿真模型,分析温度、阀口两端压差和阀口开度不同时,高速开关阀液压力的变化规律。仿真结果得知,在相同的阀口开度和压差下,液压力随温度的升高而减小;阀口开度越大,液压力受温度的影响越大;同一压差和温度下,液压力随阀口开度的增大而减小。通过探寻温度、阀口两端压差及阀口开度大小对高速开关阀液压力的影响,为准确研究高速开关阀动态特性提供理论依据,从而为提高汽车ABS响应特性奠定理论基础。     

先导式大流量高速开关阀的关键技术研究

介绍了一种新型的先导式大流量高速开关阀。先导阀采用无弹簧复位式双电磁铁驱动,大大提高了先导阀芯的开、关速度;先导阀结构形式采用二位三通滑阀式结构,加快了主阀芯上腔压力的上升与下降速度,从而提高了主阀芯的开启/关闭速度。试验结果表明,该阀在进口压力8 MPa的情况下,主阀开启/关闭时间均在0.8～1.0 ms之间。在阀口压差为1 MPa的情况下,测得的流量大于49.68 L/min。     

高压气动大流量电磁阀设计和仿真

针对有限容积减压对控制元件的要求,设计了高压气动大流量电磁开关阀,并根据其结构,运用电磁学、热力学、流体机械力学原理,建立了电磁-气热-机械耦合的数学模型。通过电磁阀的数学模型进行了计算机仿真,结果表明:电磁阀在运动过程中分为四个阶段:先导阀触动、先导阀运动、主阀运动、主阀保持。通过分析各个电磁阀参数发现,对响应时间影响较大的是前三个阶段。采用遗传算法对主要的电磁阀结构参数和控制参数进行多参数优化,取得了较好的优化效果。     

百万伏大功率操动机构液压系统优化设计

作为高压断路器核心部件之一,液压操动机构具有响应快、流量大、瞬时爆发大功率、长期等待性等特点,该文以1100kV特高压断路器液压操动机构为对象,研究基工作原理及关键部件(电磁铁,大流量高响应控制阀,高速液压缸内缓冲结构等)。基于AMESim仿真平台,建立包括电磁铁、蓄能器、高压大流量多级控制阀、高速液压缸内缓冲结构和连杆传动机构等在内的大功率操动机构液压系统仿真模型。通过实验测试的液压缸分闸过程行程曲线与仿真曲线对比,证明仿真模型的准确性,指导大功率操动机构液压系统的优化设计。     

高速开关阀的设计与研究

介绍了一种新型的二级高速开头阀,它采用柱塞式液压增益放大结构,以高速开头电磁阀为先导级,通过二级锥阀的放大,使数字阀最大流量超过80 l/min,且保持较高的切换速度,解决了大流量和快速性之间的矛盾。阀的控制器采用PWM控制原理和降幅双压驱动技术,加速电压持续时间和工作电压幅值均可调节,优化了阀的切换特性。     

基于AMESim的液压支架手动先导操纵阀液压系统分析

在综采设备中，针对手动液压阀难操作、易泄漏现象，设计了一种液压支架手动先导操纵阀，并对液压系统运行工况进行了特性分析。采用AMESim软件建立了液压系统模型，得到了先导操纵阀的反向进油口压力图、阀芯位移矢量曲线、阀芯流量曲线和反向回油口流量曲线，仿真模拟结果与实验数据相吻合。结果表明，先导操纵阀液压系统满足设计需求，能够安全可靠地运行工作。     

脉宽调制先导级高速开关阀特性研究

在大型工程机械和农用车辆上,广泛采用电液比例阀作为工作装置控制元件。PWM先导级高速开关阀在100 Hz时良好的开关性能是决定电液比例阀性能的重要因素。该研究建立了高速开关阀的数学模型,并应用基于Simulation X系统的PWM高速开关先导阀的仿真模型,对高速开关阀阀芯位移响应特性进行研究,分析了弹簧刚度、工作气隙、衔铁质量、线圈电流等参数对阀芯位移响应的影响以及高速开关阀的流量特性,给出流量控制时PWM占空比的修正公式。     

纯水高速开关阀的设计与耦合仿真分析

设计了一种纯水高速开关阀，考虑阀中电磁回路、机械部分、液压系统之间的强耦合作用，建立了耦合数学模型，并利用专用软件构建了耦合仿真模型。仿真发现，当控制脉冲采用过小或过大的占空比时，开关阀流量控制会出现死区及非线性特征；而采用较大占空比时，开关阀流量受压降影响相对较小。由于阀芯与阀套间存在较大的粘性阻尼与摩擦力，阀芯位移的阶跃响应曲线并未出现超调现象，阀芯稳定时间较短，但受电磁铁磁滞的影响，阀芯关闭时间大于开启时间；同时发现阀芯线性度随控制脉冲频率的增大而降低，减小开关阀的开启、关闭时间，有利于扩大阀芯的线性度范围。     

Transient flow analysis on opening process of pneumatic gas proportional valve with two-solenoid valve

The gas proportional valve (GPV) is a pneumatic pressure regulator, and the change in operating pressure will directly affect the opening and closing condition of the spool. In this study, the procedure for opening the spool is studied. The process of regulating the pressure of the GPV is revealed by the dynamical simulation method. The characteristics of displacement, total pressure and velocity of the spool during opening are analyzed. As time increases, it is found that the turbulence in the downstream of GPV becomes more obvious. In the process of spool movement, the influence of different inlet working pressures on spool displacement is analyzed. With a full open time of less than 1.5 × 10^ (−2) s, the spool reaches the stable state of full opening. In addition, the transient process of outlet flow is also studied. The simulated outlet flow is stable at 152 m³/h for the maximum opening. In order to verify the simulation results, the test of valve flow is carried out on the test bench. The results show that these methods can reduce the design difficulty and provide a reference for further optimization and engineering application of GPV.     

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。     

2D SIMPLIFIED SERVO VALVE

A novel pilot stage valve called simplified 2D valve, which utilizes both rotary and linear motions of a single spool, is presented. The rotary motion of the spool incorporating hydraulic resistance bridge, formed by a damper groove and a crescent overlap opening, is utilized as pilot to actuate linear motion of the spool. A criterion for stability is derived from the linear analysis of the valve. Special experiments are designed to acquire the mechanical stiffness, the pilot leakage and the step response. It is shown that the sectional size of the spiral groove affects the dynamic response and the stiffness contradictorily and is also very sensitive to the pilot leakage. Therefore, it is necessary to establish a balance between the static and dynamic characteristics in deciding the structural parameters. Nevertheless, it is possible to sustain the dynamic response at a fairly high level, while keeping the leakage of the pilot stage at an acceptable level.     

Dynamic performance of high speed solenoid valve with parallel coils

The methods of improving the dynamic performance of high speed on/off solenoid valve include increasing the magnetic force of armature and the slew rate of coil current, decreasing the mass and stroke of moving parts. The increase of magnetic force usually leads to the decrease of current slew rate, which could increase the delay time of the dynamic response of solenoid valve. Using a high voltage to drive coil can solve this contradiction, but a high driving voltage can also lead to more cost and a decrease of safety and reliability. In this paper, a new scheme of parallel coils is investigated, in which the single coil of solenoid is replaced by parallel coils with same ampere turns. Based on the mathematic model of high speed solenoid valve, the theoretical formula for the delay time of solenoid valve is deduced. Both the theoretical analysis and the dynamic simulation show that the effect of dividing a single coil into N parallel sub-coils is close to that of driving the single coil with N times of the original driving voltage as far as the delay time of solenoid valve is concerned. A specific test bench is designed to measure the dynamic performance of high speed on/off solenoid valve. The experimental results also prove that both the delay time and switching time of the solenoid valves can be decreased greatly by adopting the parallel coil scheme. This research presents a simple and practical method to improve the dynamic performance of high speed on/off solenoid valve.     

组合型节流槽对多路阀内流场特性影响的仿真研究

针对工程机械用多路阀阀口压损大、流速高,极易出现阀芯冲蚀磨损的问题,以某型号工程机械多路阀为例,设计不同组合形式的节流槽,研究多路阀阀口节流槽结构形式对阀口流阻损失及多路阀内部流场特征的影响。采用数值分析的方法研究了不同阀口节流槽形式在阀芯开启过程中阀口前后压差、流量、流速等流场特征。结果表明:阀芯采用不同组合型节流槽的流场特征明显不同,VU形节流槽较其他阀口出流线性特性更好,且具有良好的预升压效果,可进一步降低液流对阀芯的冲蚀,减小噪声、振动,保证多路阀工作的稳定性。对高压、大流量多路阀阀芯节流槽口的设计及提升多路阀综合性能具有一定的参考意义。     

基于AMESim的高速开关阀动态特性仿真研究

以某型号电子限滑差速器中的无复位弹簧式高速开关阀为研究对象，分析了该高速开关阀的结构及工作原理，并建立了机、电、磁、液等各个耦合部分的数学模型。运用AMESim建模仿真平台建立高速开关阀的阀芯位移动态响应模型，基于该模型对高速开关阀在一定PWM信号下进行动态时间响应特性仿真，分析了阀芯质量、驱动电压、黏性阻尼系数等参数对高速开关阀阀芯位移响应时间各个阶段的影响，通过仿真结果分析了响应时间滞后的原因，并从提高阀芯响应时间方面提出参数优化调整建议。