液压缸活塞杆杆体拉伤故障分析及解决措施

工程机械液压缸在使用过程中会出现活塞杆杆体拉伤现象,导致液压缸不正常工作,该文针对液压缸杆体拉伤故障进行了原因分析,并提出了建议及解决措施,对液压缸防止拉伤和再制造修复有一定指导作用。     

如何检测高精度轴类零件的波纹

我厂在生产液压支架用的各种油缸和叉车油缸中,活塞杆体镀后抛光出现各种轻重不同的波纹和螺旋纹。开始时由于检测方法不当,致使部分有螺旋纹的杆体流入了装配工序,直到用户验收提出时才发现。我们通过改进验证,认为采用如下目测方法检验镀前和镀后抛光杆体,才能杜绝带有螺旋纹和波纹的杆体流入下道工序。     

关于对油缸活塞杆动密封外泄漏的设计改进

该文通过理论计算,借助仿真分析和台架实验与整机实验,对某机型工程机械油缸外泄漏的失效原因进行分析,认识到在杆密封方案选型合理及工艺加工符合图纸要求的前提下,油液从杆动密封处外泄漏的原因除了油液里面的杂质损坏杆动密封之外,杆动密封处的外泄漏一般是以“油环”状形式间歇的向外泄漏。通过在静止状态下对油缸杆串联动密封各密封圈间的压力测试及在往复运动过程中对油缸串联杆密封各密封圈间收集的油膜油液“泵回吸”回油缸内腔的动态分析。得出除了杂质导致油液外泄外,合理设置各密封圈与活塞杆之间的间隙S和密封圈唇口前间隙为S的相对表面长度L,是降低油缸杆密封外泄漏的关键核心因子。     

矿用自卸车举升机构的优化设计

本文结合某矿用自卸车举升机构优化实例介绍了一种简单的矿用自卸车举升机构优化设计方法,解决了原来举升机构设计需要重复调整油缸支点位置测量油缸力臂进行力矩计算,工作量较大的问题,可以作为模板指导设计人员在设计矿用自卸车举升机构或验算矿用自卸车举升机构的设计合理性时迅速地得出最优的结果,缩短了举升机构的优化时间并且使优化结果能最大程度地满足设计要求。     

FTHS自卸车液压油缸系统

目前国内自卸车市场保持高速增长,自卸汽车可比普通运输车辆数倍提高使用效率,为用户提高经济收益.我国目前前顶式自卸车液压系统虽然供应商较多,但是均缺乏全套系统的设计能力,大多数厂家仅仅生产油缸,其它关键部件均靠采购,无法满足成套系统的完美匹配.我公司开发的这一项目,自行设计开发油缸、液压阀以及油泵三大关键部件,考虑整套系统的性能以及工作稳定性.     

气动液压虎钳

图示为气动液压虎钳的装配图,它由原来标准的平口钳改装而成;在平口钳后面装一个工作油缸即成。改装后的元件有:油缸体1、活塞2、油缸盖3和丝杆4等主要零件组成。油缸右端有增力器高压油进入口,高压油进入时,推动活塞2向左,带动丝杆4向左移动,活动钳口向左运动,以夹紧工件。     

基于ADAMS矿用自卸车液压举升系统优化设计

矿用自卸车的主要实现短距离内散料的运送,举升系统的性能好坏,将直接影响整车的工作效率。基于某款矿用自卸车举升液压系统的结构和工作原理,该系统采用后置直顶式多级伸缩举升油缸,在ADAMS/View中建立举升油缸的仿真模型,在ADAMS/Hydraulics中建立液压系统模型,将二者联合起来实现机械机构与液压控制之间的耦合,搭建整个液压举升系统的分析模型。引入"倾卸线",建立平装满载举升工况仿真模型。以最大举升力和举升缸最大长度为目标函数进行优化设计,考虑6个约束条件对举升液压系统进行优化设计,并在将优化结果在实车进行测试。分析结果可知:整个举升回落工作过程中,举升油缸无杆腔内出现的油压峰值个数与系统举升缸的级数n之间存在一定线性关系,即为2n+1个;发动机转速越高,举升系统内的油压冲击也就越大,冲击大小由油缸的结构特征决定;试验结果表明举升过程共用了47.2s,举升泵总排量为148.51ml/r,举升过程中无杆腔内油压一直未超过2MPa;试验结果与仿真分析结果一致,为此类车辆液压举升系统设计提供参考。     

基于Recurdyn的双空间四杆机构摩擦试验机运动分析

对双空间四杆机构摩擦试验机运动学进行了理论分析,并对空间四杆机构耦合运动关系进行了分析,采用MATLAB软件对油缸加载的位移控制曲线进行了求解。以双空间四杆机构末端实现圆轨迹耦合运动为例进行了求解,得到加载油缸的位移函数。采用多体动力学软件Recurdyn对空间四杆机构摩擦试验机进行运动学仿真分析,以MATLAB求得的油缸位移函数进行位移控制,得到双空间四杆机构末端运动轨迹为圆,验证了双空间四杆机构摩擦试验机运动学理论的正确性,得到空间四杆机构其他位置的参数,为双空间四杆机构摩擦试验机的设计提供了理论依据。     

基于ADAMS的矿用自卸车车架动态应力分析

以某矿用自卸车为背景,利用多体动力学仿真软件ADAMS建立矿用自卸车整车模型.考虑车架的变形影响将车架柔性化,通过对矿区恶劣路面的仿真得出车架在各种极限工况下的动态应力,提供了一种研究矿用自卸车多体动力学的方法.     

油缸孔波纹的消除方法

在加工汽车起重机的油缸时,孔内壁容易产生波纹缺陷,成为生产上的技术关键。为了提高油缸孔内壁质量,拟定了油缸孔内壁的加工方法。一、现场加工工艺分析１．加工对象油缸内孔直径为　１１０～２００ｍｍ,油缸长度为６．５－９ｍ,油缸材质为４５钢和ＳＴＥ４７高强度进口钢,正火硬度分别为ＨＢ１８０－２２０、ＨＢ２２２－２６３,孔内壁表面粗糙度Ｒａ０．４μｍ,圆度为０．０２９ｍｍ,内孔公差为Ｈ８。２．油缸孔加工工装油缸孔加工采用一次镗－铰－滚压成形,工装是粗镗刀与镗杆用可调固定连接,精镗刀与镗杆是浮动连接,在加工…     

Minimal Realization of Linear Graph Models for Multi-physics Systems

An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...     

INTEGRAL EQUATION METHOD＇S APPLICATION IN HOLE-EDGE STRESS OF COMPOSITE MATERIAL PLATE WITH DIFFERENT SHAPED HOLES

The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material. The holes will lead to mutations and discontinuity to the structure. So the hole-edge stress concentration is always a serious phenomenon. And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points. Most partial damage begins from these weak points. According to the complex variable functions theory, the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes. Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction. The boundary integral equations are founded based on exact boundary conditions. Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved. Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed. And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made. It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient; and smaller angle of outer load and fiber can decrease the stress peak value.     

Non-monotonic material contrast in scanning ion and scanning electron images

30 keV Ga⁺ focused ion beam induced secondary electron (iSE) imaging was used to determine the relative contrast between several materials. The iSE signal compared from C, Si, Al, Ti, Cr, Ni, Cu, Mo, Ag, and W metal layers does not decrease with an increase in target atomic number Z₂, and shows a non-monotonic relationship between contrast and Z₂. The non-monotonic relationship is attributed to periodic fluctuations of the stopping power and sputter yield inherent to the ion–solid interactions. In addition, material contrast from electron-induced secondary electron (eSE) and backscattered electron (BSE) images using scanning electron microscopy (SEM) also shows non-monotonic contrast as a function of Z₂, following the periodic behavior of the stopping power for electron–solid interactions. A comparison of the iSE and eSE results shows similar relative contrast between the metal layers, and not complementary contrast as conventionally understood. These similarities in the contrast behavior can be attributed to similarities in the periodic and non-monotonic function defined by incident particle–solid interaction theory.     

Short-Term Relay Quality Prediction Algorithm Based on Long and Short-Term Memory

The fraction defective of semi-finished products is predicted to optimize the process of relay production lines, by which production quality and productivity ar...     

End-to-End Multiview Gesture Recognition for Autonomous Car Parking System

The use of hand gestures can be the most intuitive human-machine interaction medium.The early approaches for hand gesture recognition used device-based methods....     

Application of Feature Extraction through Convolution Neural Networks and SVM Classifier for Robust Grading of Apples

This paper proposes a novel grading method of apples,in an automated grading device that uses convolutional neural networks to extract the size,color,texture,an...     

分布动态载荷识别的抗噪处理

针对正交多项式频域法在用多种响应对矩形薄板进行载荷识别中抗噪性较差的问题,综合运用平均法、矩阵预处理和奇异值截断法等方法对之进行改善,并引入空间映射的思想,将该方法的应用范围拓展为复杂的模型.利用仿真算例,证实了该方法具有较好的抗噪性.     

基于MELTAC-N平台的核电厂安全级DCS环网研究与测试

针对工程实践中环网通讯相关问题的处理缺乏理论基础及国产化安全级DCS平台的开发缺乏成熟经验借鉴问题,对基于MELTAC-N平台核电厂安全级DCS环网的软硬件实现进行了研究。提出了安全级DCS环网双环网冗余设计、光切换开关设计等硬件设计方法,以及以RPR协议为基础,采用全数据收发策略的软件设计方法。在CPR1000安全级DCS平台上对安全级DCS环网的可靠性及实时性进行了评价,并进行了容错能力、响应时间及响应时间稳定性测试验证实验。结果表明,基于MELTAC-N平台安全级DCS环网软硬件设计具有较好的容错能力及响应时间稳定性。     

The laboratory simulation of abrasive wear

Abrasive wear has long been recognised as one of the most potentially serious tribological problems facing the operators of many types of plant and machinery; several industrial surveys have indicated that wear by abrasion can be responsible for more than 50% of unscheduled machine and plant stoppages. Locating the operating point of a tribological contact in an appropriate operational ‚map’︁ can provide a useful guide to the likely nature and origins of the surface degradation experienced in use, though care must be exercised in choosing the most suitable parameters for the axes of the plot. Laboratory testing of materials and simulations of machine contacts are carried out for a number of purposes; at one level for the very practical aims of ranking candidate materials or surface hardening treatments in order of their wear resistance, or in an attempt to predict wear lives under field conditions. More fundamentally, tests may be aimed at elucidating the essential physical mechanisms of surface damage and loss, with the longer term aim of building an analytical and predictive model of the wear process itself. In many cases, component surface damage is brought about by the ingress of hard, particulate matter into machine bearing or sealing clearances. These may be running dry although, more usually, a lubricant or service fluid is present at the interface. A number of standardised wear test geometries and procedures have been established for both two- and three-body wear situations, and these are briefly described. Although abrasive wear is often modelled as following an ‚Archard’︁ equation (i.e. a linear increase in material loss with both load and time, and an inverse dependence on specimen hardness) both industrial experience and laboratory tests of particularly lubricated contacts show that this is not always the case: increasing the hardness differential in an abrasively contaminated lubricated pair may not always reduce the rate of damage to the harder surface.     

ANGULAR DISTORTION ALLOWABLE VALUE AND ASSESS METHOD OF WELD ON COKE TOWER

A graph as the new engineering method for estimate the safety of bulging deformation of coke tower is proposed. Through stresses analysis of circumferential weld of coke tower and comparing the stresses produced by pressure with heat stress of steady state, residual stress, bending stress produced by both itself weight and wind loads, it showed that the stresses produced by pressure on the angle distortion are the main factor of equivalent stress of the combined stress. After comparing four kinds of stress controlling conditions, the relation to stress with depth of angular distortion, grade of curvature of angular distortion and half of region of angular distortion has been inferred. Graph of deformation allowable value of coke tower for different condition by angular distortion and half of region of angular distortion has been plotted. The five steps for its engineering use have been explained. The lighter the grade of curvature is, the larger of bulge allowance, may be, and the bigger of depth of angular distortion may pose too. For the coke tower with a popular structure of Dg 5 400 mm×28 mm, the result by graph is nearly more than the result of two formulas formed by other research, the error is less than 7.0%. But, the graph can be easily applied to different size of angular distortion.