液压泵污染磨损的试验研究

液压泵是液压系统中的关键元件。当前我国使用的液压泵故障较多、寿命较短,这和系统的严重污染是直接有关的。为了研究和分析污染物对液压泵的磨损,对其性能、寿命的影响,以进一步改进液压泵的结构,提高泵的抗污染磨损能力,确定系统的合理过滤精度,作者设计制造并安装了液压泵污染磨损(污染敏感度)试验台。一、试验台及其液压系统试验系统为开式液压系统,如图1所示。主要包括以下三个同路。一、主回路该回路对被试泵1的耐污染磨损性能进行试验。辅助泵2从油箱8-1吸油,将油液送入被试泵。自被试泵1排出的     

液压泵污染磨损试验方法的研究

一、前言污染磨损是液压泵的主要失效形式之一。为了评定不同尺寸颗粒对液压泵的磨损作用,美国俄克拉荷马州立大学流体动力研究中心提出了液压泵污染敏感度试验方法,该方法已被接受为国际标准试验方法〔1〕。液压泵污染敏感度试验标准方法是在试验系统内加入分级的空气滤清器细试验粉尘(ACFTD)作为颗粒污染物,通过检测泵的流量下降量来评定泵的污染敏感性。试验时依次增大试验粉尘的颗粒尺寸范围,从0-5,0-10、0-20……直到0-80微米。每次加入某一尺寸范围的试验粉尘后,泵在额定工况     

高压齿轮泵污染磨损的寿命模型研究与验证

工程应用案例中常常遇到齿轮泵的实际使用寿命远低于开发设计中的预期寿命情况。针对这一现象,提出了固体颗粒在液压油污染条件下的敏感度概念,并建立齿轮泵在颗粒污染下的预测寿命模型。以某轴向补偿外啮合齿轮泵为研究对象,设计一台关于齿轮泵污染敏感度试验装置,系统中输入一定浓度尺寸的固体颗粒,得到分布颗粒的污染敏感度参数,依据计算固体颗粒在NAS1638标准下的分布情况,获得泵在不同污染等级下的磨损预测寿命。同时绘制出被试泵在NAS10级污染下磨损寿命为2000 h的污染耐受度曲线。研究结果具有一定的工程应用价值,能够定量分析和比较被试泵的污染耐受性、预测泵在不同颗粒污染等级下的性能变化规律和污染磨损寿命,可为高污染耐受泵的设计提供参考。     

纯水外啮合齿轮泵磨损机理研究

污染磨损是液压泵寿命的决定因素，该文介绍了液压泵污染敏感度理论，分析外啮合齿轮泵的主要磨损机理，并利用所述的磨损机理提出各种控制磨损策略。     

液压油清洁度检测

1.液压油固体污染物的危害固体颗粒污染比空气、水和化学污染物等造成的危害都大。固体颗粒与液压元件表面相互作用时会产生磨损和表面疲劳,使内漏增加,降低液压泵、马达及阀等元件的工作可靠性和系统效率,更为严重的可能造成泵或阀卡死、节流口或过滤器堵塞,使系统不能正常运行。     

航空液压泵加速寿命试验现状及方法研究（连载4）航空液压泵的寿命影响因素研究与分析

从定量研究航空液压泵环境工况参数与寿命之间关系的需求出发,介绍了影响航空液压泵寿命的因素与磨损寿命定量关系研究的方法。温度提升对于泵寿命的影响主要在于改变摩擦副油膜特性,从而劣化其润滑摩擦状况,加速磨损。分别介绍了基于试验、解析和数值方法对摩擦副油膜特性的研究成果,并对比分析了各种方法的优点和局限性。针对使用流体-固体-热耦合模型的油膜特性分析方法进行了详细说明。最后,对现有的基于油膜特性分析的磨损寿命估计方法、加速寿命试验方法,寿命模型的校核和验证方法进行了总结。     

采煤机主泵配油盘的污染磨损研究

对采煤机主泵配油盘磨损失效进行了分析研究,证实了配油盘的主要失效机理是有润滑的磨粒磨损。通过对实际的不同选材和表面强化工艺的配油盘进行有油液污染物的污染磨损台架试验,结果表明:几种配油盘中以表面镀有氮化钛(TiN)的高速钢W18Cr4V的抗污染磨损性能为最佳。就采煤机主泵配油盘的材料和表面强化工艺的选择提出了建议。     

液压泵阀在有污染颗粒时的磨损特性[博士论文摘译]

液压油中不可能绝对没有污染颗粒。为了减少由于污染引起的液压系统的磨损损坏,除了采用恰当的过滤以外,还一定要提高液压元件的抗磨损能力。雅各布教授在攻博期间通过大量实验研究了变量泵与比例换向阀的磨损特性,指出了一些提高液压元件抗磨损性能的途径。     

航空液压泵寿命影响因素研究

航空液压泵温度的提升会对泵的寿命产生影响,主要原因是摩擦副油膜的特性在发生改变,导致润滑摩擦出现劣化现象,从而使磨损加速。温度、油膜特性对航空液压泵的寿命产生直接的影响。鉴于此,本文立足航空液压泵的寿命问题,简要分析了航空液压泵的寿命影响因素,以期对今后的使用和研究提供建议。     

循环流化床锅炉磨损机理及防磨技术

循环流化床锅炉的耐磨损性问题严重限制了其实际应用和持续发展。基础科学研究其耐磨损性反应机理和抗磨科学技术具有重要的理论和现实意义。在结构分析循环流化床锅炉水冷壁耐磨损性基本规律和失效行为的基础上,基础科学研究了不锈钢锅炉管快速磨损的失效机理,提出了部分磨损的微重耐磨损性模型。基础科学研究表明,快速耐磨损性是非常重要的,其原因不是由于中长距离犁煤机和犁煤机炉内的大面积均匀分布磨损度,而是由于局部微磨损、轻微磨损度。磨损度是大角度颗粒物冲击磨损和小角度颗粒腐蚀性磨损的结合。结合非刚性颗粒物的二次腐蚀,可以在一段时间内在管壁上形成小而深的磨损。磨损坑的微观形色是磨损表面与一定角度的相互性。     

液压柱塞泵运动副磨损特性研究综述

针对液压柱塞泵的3对主要运动副:柱塞-缸体副(柱塞副)、缸体-配流盘副(配流盘副)、斜盘-滑靴副(滑靴副),对国内外围绕3对运动副磨损特性相关的研究进行了汇总和总结。柱塞泵运动副间隙的润滑形式为粘弹性动力润滑(EHL),磨损特性与油膜、介质、污染、运动副材料及表面形貌等密切相关。主要介绍了柱塞泵运动副的润滑磨损理论研究,影响磨损特性的运动副油膜特性相关研究成果,以及适用于柱塞泵运动副的磨损模型。对比分析了柱塞泵磨损特性研究常用的解析方法、仿真方法、实验方法,介绍了每种方法的优势及局限性。最后对影响柱塞泵运动副磨损特性的关键因素进行了总结,给出了有待解决的问题及研究方案。     

Active control of hydraulic oil contamination to extend the service life of aviation hydraulic system

The hydraulic system is the control center of aircraft, the performance of which is critically dependent on the purity of the oil that flows through it. Contamination of hydraulic system oil has been known to be the primary cause of catastrophic failure and accidents. A review of literature in the area of hydraulic oil contamination reveals three facts: (i) there is a dearth of effective methods to prevent intrusion of external contaminants into the hydraulic oil, (ii) there are no effective purification methods for liquid and gaseous contaminants of oil, and (iii) there is an absence of real-time monitoring for major contaminants. This work systematically reviews the hazards, sources, and removal methods of major contaminants, especially of gaseous contaminants. An active method to control oil contamination is proposed instead of the existing passive maintenance techniques that are ridden with problems. In a case study of aviation hydraulic system, our active control system comprises (i) a closed hydraulic circuit and a closed oil tank to prevent the intrusion of external contaminants, (ii) a vacuum centrifuge to efficiently remove contaminants without creating consumption costs, and (iii) monitoring devices installed to actively monitor the contaminant content in oil during operation. The results from the purification experiments and three-dimensional modeling indicate that the active control of hydraulic oil contamination can effectively remove 98.4% solid contaminants and reduce the water content below 50 ppm, and in particular reduce the gas content below 2%. It is obvious that this method can improve the continuous operation capability of aviation hydraulic systems and extend the intermaintenance period of aircrafts by reducing the contaminant content in oil.     

基于润滑机理的智能液压元件本体性能预测方法

以液压泵为例，以其最为薄弱的环节--滑靴副为研究对象，并以滑靴磨损作为性能退化原因，结合滑靴磨损数学描述方程、泄漏流量公式和柱塞腔压力瞬时变化模型，建立了滑靴磨损过程的油膜润滑特性方程组；揭示了液压泵性能失稳失效机理，计算了失稳和失效临界点；对液压泵性能退化状态进行区域划分，分析液压泵不同状态下滑靴磨损量与油膜润滑特性参数及性能退化参数的变化规律，建立了性能预测模型；通过仿真分析验证理论模型的正确性，通过液压泵性能测试试验验证预测模型的有效性和预测精度，结果表明，所构建的模型能够精确预测液压泵性能。     

水压往复柱塞泵新型密封结构设计与分析

载人航天器环控生保系统中,迫切需要一种小型长寿、能可靠实现精确输送的柱塞泵,要求工作在空间微重力环境中稳定运行,并具有极低泄漏率和磨损率。往复动密封性能决定柱塞泵寿命、泄漏量、磨损率,针对相应特殊要求,开展水压往复柱塞泵的设计。借鉴传统油压往复密封理论与实践经验,设计一种适应低黏度水介质,容纳磨损颗粒物,确保低泄漏率,具有封间泄压机制的新型串联动密封结构。并采用有限元软件对主密封进行接触应力分析,根据介质压力与比压判据,确定最优的初始压缩量。考虑密封元件微观形貌,对雷诺方程进行数值求解,讨论成膜条件,确定合理量级的运动参数,以进一步优化密封结构。     

Aspects of paper abrasivity

The mechanism of wear by paper is reviewed, and it is established as being primarily abrasive. The severity of this type of wear is compared with other wear processes and shown to be relatively mild. In addition, new data regarding the effects of paper damage, paper debris and moisture on the abrasivity of paper are presented. In general, it is shown that the individual and combined effects of these factors reduce the abrasivity by as much as one to two orders of magnitude under certain conditions.     

Abrasivity and grindability study of mineral ores

The results of the milling experiments of different mineral ores and laboratory wear testing with different abrasives have shown that the abrasivity of treated materials does not depend only on their hardness, but, to a great extent, on the particle shape of the materials. The grindability of materials milled by collision depends on the properties of materials as well on the treatment parameters (specific treatment energy). The aims of this investigation were (1) to study the abrasivity and the grindability of different minerals (granite, quartzite, etc.) and (2) to predict the relative wear resistance of the materials prospective for the grinding media of milling equipment, using a centrifugal type impact wear tester. Experiments conducted with abrasives of different hardness and with particles of different shape have shown that the wear rate of materials used as wear resistant materials in grinding devices depend more on the angularity of abrasive particles than on their hardness. It was shown that the grindability depends more on the composition and properties (fracture toughness, homogeneity of the structure) than on the hardness of the mineral ores. The main size reduction occurs at first collision, later in the multiple milling of mineral materials particle rounding takes place. The angularity parameter has good correlation with the wear rate in the case of the studied commercial steels as well as with metal matrix composites. Experiments with cermets showed that erosion does not practically depend on abrasive particle shape.     

A new method for measurement of particle abrasivity

A modified micro-scale abrasive wear test has been used to study the abrasivity of a range of silica and calcium carbonate abrasives in aqueous slurries, against polymethylmethacrylate (PMMA) samples. The method involves the rotation of a cylindrical disc against the specimen surface in the presence of small abrasive particles, and generates a wear scar with an imposed geometry. It allows a wider range of particle sizes to be used than the more conventional ball–cratering method. For the abrasives used in these tests, differences in abrasivity by a factor of at least 16 were found. The main factor which influenced abrasivity was particle shape.     

基于故障机理的液压泵多信息烈度特征状态评估方法

以液压泵滑靴磨损故障为例,提出一种基于故障机理的多信息烈度特征状态评估新方法。该方法从滑靴磨损机理出发,利用滑靴副压紧系数值对滑靴不同磨损程度对应的液压泵工作状态进行区域划分;通过振动烈度的频域计算方法提取泵壳体振动、出口流量及压力三种信号的烈度特征因子,分析三种烈度特征因子对滑靴磨损程度的敏感性,并建立特征因子样本集;利用最小二乘法进行数据拟合,得到三种烈度特征因子与液压泵工作状态的对应量化关系,结合BP神经网络和D-S证据理论建立基于多信息决策融合算法的状态评估模型。通过测试样本验证了模型的有效性,结果表明该模型具有较高的评估精度。