液压油越来越新

ER油液很可能为液压装置及系统的发展开辟新路。     

可移动液压油去污系统的设计与应用

液压系统中绝大部分故障来自液压油，主要是液压油被污染造成的。简单有效的措施是去除油液中的杂质颗粒、保证油液的清洁度。该文介绍了所开发研制的可移动油液去污系统。该系统投资少，可完成油液过滤除杂、注入以及废油的排放，在实际应用中能使液压设备故障减少60％-70％，延长波压油使用期限3-4个月。     

液压油的污染与控制

本文针对液压油的污染种类和原因，提出了控制液压油污染的措施，并介绍了两种实用的污染测定方法，目测法和比色法。     

液压油的选用与维护

机械设备是工业生产中的基础生产资料,随着科学技术的进步,机械设备的发展趋势是元部件越来越精密,因此,设备的维护与保养是否得当是企业能否缩小预算、节约开支的关键。如何用好油,合理润滑,减少污染是本文的重点。1 液压油的种类 液压油可分为三大类:矿油型、合成型和含水型。国内常用的液压油有L-HL液压油、L-HM抗磨液压油、L-HV低温抗磨液压油、L-HS低凝抗磨液压油、L-HG液压导轨油和抗燃液压油等。 油品的主要性能及适用范围: (1)L-HL液压油:具有一定的抗氧防锈和抗泡性,适用于系统压力低于7MPa的液压系统和一些轻载荷的齿轮箱润滑。 (2)L-HM抗磨液压油:除了具有L-HL液压油的性能外,抗磨性能强。适用于系统压力7～     

浅谈液压油的污染与过滤

液压油品的过滤是液压系统污染控制的主要手段,着重介绍液压油使用过程中可能产生的污染问题以及过滤操作的正确使用,以确保液压系统有满意的工作和使用寿命。     

液压油管钳液压系统的改造

液压油管钳是油田修井作业的专用工具,已在各油田得到广泛应用,但各类液压钳都没有扭矩控制装置,普遍存在着油管上扣扭矩过大,致使卸下油管时油管严重磨损或粘扣而割断报废的现象。本文提供了一种扭矩控制措施,供参考。 300型液压钳是油田最常用的液压钳,在其液压系统中,马达可输出的上、卸扣扭矩相同。而在实际使用中,由于井中高温、高压及重载等因素会引起油管变形,液体、气体的腐蚀导致丝扣生锈粘合,从而使卸扣扭矩要比上扣扭矩大很多。为了满足液压钳控制     

液压油过滤再利用

液压油在机械设备中常用来传递运动和动力、对运动副进行润滑、冷却。而清洁的液压油是液压系统正常工作的必要条件之一。由于众多因素,如系统加工、装配、运储过程中“潜伏”下来的各种污垢,系统使用过程中通过往复伸缩的活塞杆、泄漏油的回流、空气水分等浸入系统的污垢,系统工作过程中由于磨损而自行产生的金属粉末、橡胶颗粒等污垢,液压油氧化变质所生成的胶状物等污垢,都会使油液因污染而性能降低甚至无法使用,从而形成液压废油。     

高低温环境对液压油的影响

液压油是液压系统实现动力传递的重要工作介质之一,同时还对液压系统起到润滑、防锈、缓冲、冷却等作用。随着液压技术的不断发展,对液压油的使用要求越来越高,特别是环境温度的影响。我国地域广阔,南北环境温度差异较大,一月份气温在-1 8°C以下的地区占全国面积的5 6 % ,部分地区冬季最低气温达- 5 0°C。而南方的最高室外气温高达5 0°C ,同时,野外作业的机械设备的环境温度可达70°C～80°C ,油温则高达1 30°C。这些地区的一些机械设备需要露天作业。对于一般的工程机械,在不同的环境条件下使用相应的液压油就较容易解决这个问题。…     

液压油的污染与控制

在液压系统中,大部分故障都是由于液压油的污染造成的。而对于液压伺服控制系统来说则对液压油的清净度标准要求更高。这更需要防止液压油被污染。 1.机械杂质对液压油的污染与控制 液压油中混入的机械杂质主要有以下几种: (1)液压系统及元件的加工、装配、贮存、运输等过程中所产生的型砂、切屑、磨料、灰尘等已潜伏     

液压油使用中应注意的问题

1 注意液压油的污染(1)由于液压设备运行时,液压系统中的油管接头、法兰、液压油泵、控制元件、蓄压器、液压缸等部件的连接部分,或结合面处,由于种种原因造成不密封,使液压油箱、油池产生气泡及液压油变质,继而使空气进入整个系统,不但使油变质,甚至造成不能使用,影响了设备的工作性能。为了保证工作质量,应及时注意更换不良的密封件。例如采取降低液压油泵的安装高度,正确选择密封件和油,以防止空气混入。     

液力变矩器在工程机械中的正确使用与检查

液力变矩器由于能够自动适应负载变化、调整工作速度 ,并且缓和冲击、延长机械寿命 ,从而在工程车辆 (装载机、推土机、自卸车等 )上得到了广泛使用。其主要缺点是成本较高 ,传动效率较低。工作中必须注意正确使用工作油 ,正确使用液力元件 ,作好定期检查和维护 ,才能提高工作的可靠性 ,保障机械的正常使用寿命。1　液力变矩器正常工作的压力补偿系统液力变矩器正常工作时 ,需要解决的问题是 :首先 ,变矩器正常工作时 ,平均效率大约为0 7左右。损耗的能量使油及有关零件的温度升高。油温是决定变矩器油液使用寿命的重要因素。如果热量不能…     

电流变液技术在液压控制系统中的应用

电流变液是一种流变特性可受外加电场控制的智能材料,该文阐述了电流变液材料的组成、特性和作用机理,介绍了电流变液技术在液压控制系统中的应用.     

Laboratory parameters for high water based hydraulic fluid testing

A review of the composition and properties of current water-containing hydraulic fluids leads to the conclusion that current technology could be improved towards a high water containing fluid with good antiwear, low toxicity and high fire resistance characteristics. A modified pump test was used based on ASTM D2882, using a Vickers V105C apparatus. Wear rate data is presented for various candidate fluids including a full synthetic, showing differences between HFA, HFB, HFC and HWBF and looking at variations in break-in wear and subsequent wear behaviour. Data is also presented for candidate fluids tested in industrial-type hydraulic pumps, and illustrates the role of viscometric properties including shear stability.     

Wear testing and specification of hydraulic fluid in industrial applications

The aim of this paper was to investigate the possibilities to use a model test to simulate the wear between cylinder bore and piston in a radial piston hydraulic motor. The tests were performed in a reciprocating test rig where the contact geometry is of the cylinder–plate type. The influence of different types of commercially available hydraulic fluids on wear protection and friction was studied. From the study, it was concluded that the use of water glycols can cause increased wear in hydraulic motors operating in low speed applications. It was also seen that the FZG test alone appears not to be enough as a hydraulic fluid wear test, at least not in the tribological conditions present in the performed wear test.     

液压阀非定常流场数值模拟及分析

为深入研究阀体内部流场结构,采用非定常数值模拟方法对某液压锥阀3种不同开度下的流场进行数值模拟,并对其进行对比分析。成功地捕捉到液压锥阀的非定常流场,液压锥阀中等开度下的流场呈周期性变化;保持进口流速不变,随着开度增大,阀芯所受压力逐渐减小,主流区宽度逐渐增大,角区漩涡面积增大,阀芯上部漩涡区逐渐减小。     

矿山机械液压油污染在线监测系统设计

对矿山机械液压油污染的来源及危害进行分析,针对现行液压油污染监测技术的不足,提出一种新的在线监测技术,为矿山机械先进液压油污染监测系统的研制提供参考。     

Modelling of fluid continuum considering 3D surface parameters in hydraulic assemblies

Friction in servo hydraulic assemblies reduces the response characteristics of the system. The friction is influenced by various factors including the geometry (form and surface errors) of the sliding surfaces. In this work, functionally significant 3D surface parameters from the Birmingham parameters are investigated for reduced friction. A 3D surface modelling approach is presented using random process modelling as the basis. An exponential decay areal autocorrelation function is used to model the grinding and honing processes which are commonly employed for the manufacture of the hydraulic assemblies. Honed surface is modelled with the crosshatches of appropriate angle. Method of surface modelling is validated using the data obtained through measurements on a practical surface. Different surface maps with varying surface parameters of the ground and honed surfaces are generated. The fluid continuum gap geometries of the hydraulic assemblies are modelled using these surface maps as envelopes. Pressure distribution, velocity and viscous friction force are used as measurands of the frictional characteristics. Using computational fluid dynamics (CFD) approach, these measurands are evaluated for different functionally significant Birmingham parameters. Based on further analysis, negative skewness, lower kurtosis values, higher valley fluid retention index were found to have lower frictional characteristics.     

Chlorotrifluoroethylene oligomer based nonflammable hydraulic fluid. 2 Hydraulic components' development

A requirement for a nonflammable hydraulic fluid was defined in the 1970s to eliminate losses attributable to hydraulic system fires. In order to increase the possibility of success of the nonflammable hydraulic fluid development programme, requirements for compatibility with current hydraulic fluids, seals, and system designs were not established. All previous attempts to develop a compatible nonflammable hydraulic fluid had been unsuccessful. Extensive screening of many chemical classes of candidate base fluids led to the selection of a Chlorotrifluoroethylene (CTFE) oligomer. Considerable hardwarel system development was performed for hydraulic system applications, including development of high-pressure actuators, pumps, and motors. The major thrust of the programme, a totally new system design, was demonstrated in the Lockheed High Technology Test Bed air craft and in the McDonnell Douglas Aircraft 55.2 MPa (8000 psi) technology ‘Iron Bird’ demonstrator. Possible retrofit applications for current systems include a C135E fireproof brake system and the M1/M1A1 Abrams tank gun mount. This paper also discusses material compatibility requirements, design considerations, and the results of pump testing of the nonflammable hydraulic fluid.     

多层次模糊综合评判法在液压油性能评价中的应用

影响液压油性能的因素很多。包括诸多不可量化的因素。针对目前对液压油性能的评价一般仅局限于对液压油的污染度等理化性能进行评价,提出了利用模糊综合评价法,从液压油的理化性能指标、模拟性指标、性能试验指标3个方面来综合评价液压油性能的新方法。