液压提升器油缸拉缸原因分析及控制措施

对拖拉机液压提升器提升油缸拉缸的原因进行分析，并提出了控制措施。     

液压油缸的密封设计

探讨液压油缸密封间隙中油液运动的规律,分析各部位缝隙中压强的分布情况等,对液压元件的设计,提高液压油缸的密封性能,有着重要的意义。1.影响液压油缸密封的因素下面我们仅就缝隙大小和压强分布情况,分析对液压油缸密封性能的影响。如果液压油缸内的压强为P_S,柱塞杆与导向套是平行无偏斜的理想状态时,可以看作是平行平面间的缝隙。     

基于流固耦合的长行程液压油缸强度仿真分析

以某型长行程液压油缸作为研究对象,应用流固耦合(FSI)的方法,对缸筒和活塞杆进行强度、刚度计算.在液压油缸设计工况下,首先通过采用有限体积法计算缸筒内部液压油的流场,获得液压油对缸筒筒壁的作用力;再通过有限元法,以缸筒内部流场的计算结果作为边界条件,同时添加工作阻力,对整个液压油缸进行了强度及刚度校核.通过获得缸筒和...     

基于虚拟样机的液压挖掘机工作装置最大挖掘力分析

针对液压挖掘机工作装置挖掘力的分析计算与优化问题,对工作装置在斗杆挖掘工况下的最大挖掘力及工作装置关键铰接点空间位置对其最大挖掘力的影响进行了研究,提出了采用机械系统与液压系统联合仿真的方法,建立了某液压挖掘机工作装置的虚拟样机模型,分析斗杆油缸以系统最大压力工作,铲斗油缸、动臂油缸闭锁时,在整个挖掘范围内,工作装置的挖掘力图谱,并确定了最大斗杆挖掘力.在此基础上,以最大斗杆挖掘力为设计目标,通过试验设计方法,研究了工作装置机构铰接点空间位置对斗杆挖掘工况下最大挖掘力的影响.研究结果表明,液压挖掘机最大挖掘力达到国外同类产品水平,同时找出了铲斗最大挖掘力位置及数值,为工作装置优化设计和结构强度分析提供了有效依据.     

“转向油缸”难装配质量攻关纪实

为解决某机型装载机"转向油缸"出现的难装配问题,技术工艺部开展了"转向油缸"难装配质量攻关,通过提高"后耳座孔与铰接孔的平行度","转向销装配性"等措施,来改善"转向油缸"的装配质量。工艺改进试验反馈,"转向销"难装配比例从原来的接近35%(每台2根"转向销",以难装配数量除以台数计算)降至1.8%,"转向油缸"上浮比例从原来的51.2%(每台2根油缸,以上浮数量除以台数计算)降至17.1%,"转向油缸"的装配质量得到明显提高。     

一种外置弹簧缓冲结构的液压油缸

通过对除雪工作装置结构进行分析,发现此类内置弹簧缓冲油缸结构会限制内置弹簧的设计尺寸区间,从而导致内置弹簧的缓冲力局限在很小的范围。液压油缸在缓冲力及其有限的内置弹簧结构下工作,工作装置与阻碍物发生碰撞时,冲击力超过了液压油缸的缓冲上限,缓冲性能不足。因内置弹簧缓冲的油缸存在以上诸多缺陷,针对性地开发了外置弹簧缓冲油缸,创新性地引入弹簧导向杆结构,液压油缸受外力冲击/载荷时,可充分引导缸头座同步进行轴向运动,当外力冲击/载荷减小或消失时,弹簧、缸头座复位完成缓冲工作,解决了缓冲性能不足问题,提高了推雪作业效率,但在实际使用过程中,因液压油缸缸头导向杆小杆与缸头座结构设计问题,易出现液压油缸缸头导向杆塑性变形,降低液压油缸使用寿命。对外置弹簧缓冲结构优化后的液压油缸进行仿真分析,优化结构后缸头导向杆能承受更大弯矩,发现缸头座对弹簧导向杆产生的应力不会使得液压油缸发生塑性变形。优化方案已在柳工D系列平地机上得到实际验证。     

基于SimulationX的挖掘机高压斗杆缸缓冲装置的仿真与试验研究

为研究高压油缸的行程末端缓冲装置的缓冲性能,获得油缸缓冲行程阶段的压力、流量等参数,以一款国产挖掘机高压斗杆缸作为研究对象,将计算机仿真技术应用到实际工程研究中。基于SimulationX仿真软件搭建了挖掘机工作装置液压系统的仿真模型(特别是缓冲模型),开展了液压-机械多体动力学联合仿真;在典型工况下对液压挖掘机斗杆缸的压力、流量等参数进行了试验,通过比对仿真结果,对控掘机液压系统仿真的准确性进行了评价。结果表明,所建立的仿真模型是合理的、科学的,该仿真技术在工程领域更进一步的推广是可行的。     

落地镗床妙用超精磨头削大油缸

落地镗床妙用超精磨头削大油缸张忠问（天水锻压机床厂天水７４１０２０）油缸是液压传动中的主要零件。其粗糙度的好与差将影响整机性能和寿命。我厂生产的剪板机和折弯机的油缸，Φ３６０ｍｍ以下的油缸均在车床车出后，用自制的超精磨头在车床上将孔磨削好。多年来已取...     

自卸荷式活塞油缸

在油缸较多的机械中,常产生活塞行程到头而操纵者不易发现,致使油压升高,损坏液压零件。因此,我们改制了一种能在活塞行程到头时,自动卸荷的油缸,效果很好。油缸的结构如图所示,当油从缸左端进入时,经B孔到C腔(活塞杆上开的通槽,使小阀杆9向右行,其锥面将导向套8的内孔堵死。油缸左右两腔膈绝,活塞开始右行,当到达缸底时,小阀帽7先被缸尾6顶住,使小阀杆     

煤矿井下液压支架油缸泄漏故障及维修分析

基于油缸泄露会产生影响生产进度、浪费资源和影响环境的问题,从不同方面对油缸泄漏的问题进行分析,包括安装尺寸不精准、材质选择不合理、密封装置表面损伤、工作环境影响和老化现象等,并探讨了密封件、缸筒、缓冲阀和初撑力的检查与维修方式,以保证油缸的密封性,保障液压支架的正常作业。     

Scuffing failure analysis and experimental simulation of piston ring–cylinder liner

The scuffing failure phenomenon of piston ring–cylinder liner is studied theoretically and experimentally. The load and bulk temperature when scuffing failure occurs are measured under different engine speed, lubricant, and environmental temperature in a bench test. Based on the experimental results, the asperity capacity when scuffing occurs is evaluated. Surface contact temperature is determined with the measured bulk temperature and the surface flash temperature calculated by Blok theory. The scuffing failure threshold of piston ring–cylinder liner is established by using specific oil film thickness. This revised version was published online in June 2006 with corrections to the Cover Date.     

Misalignment effects on the load capacity of a hydraulic cylinder

Analytical and experimental investigations of typical hydraulic cylinders have indicated that their load capacities are significantly different from those obtained from simple buckling analysis of idealized systems. In any case, an increase in the friction coefficient at the restrained ends changes the actuator's limit load, while an increase in the initial maximum deflection (initial misalignment) decreases the limit load. A common practice of most cylinder manufacturers is to use a safety factor (between 2.5 and 4) to determine the service load after the critical load (buckling) is obtained by simple analytical procedures treating the cylinder as a perfect stepped column. The intricate aspects of friction effects have been deliberately left aside in this present work. Nevertheless, friction and interaction between mechanism and actuator in the buckling characteristics will be presented in the ongoing paper, which will follow this work. Authors know that, in a real system, the cylinder tube-rod interface is not rigid. Due to the flexibility of guide rings and clearances between components, misalignment (an angular deflection which increases with increasing axial load) exits at the interface. When initial imperfection angle exists, there is no sudden buckling. Then, stresses and deflections increase with increasing load. After repetitive use, the tolerance between the parts will become larger, consequently increasing the initial deflection, which has been proved to considerably decrease the load capacities of the power cylinders. From this analysis, a theoretical and experimental work has been carried out in order to show the advantages and disadvantages of the current design methods, characterizing the critical factors that cause the collapse and proposing useful design criterions. The present work aims to describe the behaviour of actuators under load capacity with experimental validation.     

60t铜排拉拔机液压缸的设计与分析

连续挤压生产出的铜排,需要通过拉拔机进行拉拔,以达到使其硬化和改善表面质量的目的.液压缸是液压拉拔机的重要部分,为拉拔提供动力.而这种液压缸长径比大于40,由于其自重产生的挠度会对液压缸的工作产生影响.传统设计长行程液压缸多是参照液压缸设计手册.对液压缸长径比小于40可行,但是对于液压缸长径比大于40的并不适用.采用联动方程对60t液压拉拔机的液压缸进行设计与分析,使其满足工作要求.这种方法不但对60 t液压缸适用,同时适用其它吨位长行程的液压缸.     

对称四通阀控液压缸建模研究

根据对称阀控非对称液压缸的特性,重新定义了负载压力和负载流量,推导出同时适用于对称阀控非对称液压缸和对称阀控对称液压缸的数学模型,为对称阀控液压缸系统的稳态和动态特性分析及液压控制回路的创建提供了理论依据。     

基于ADAMS的装载机液压系统压力提升性能研究

应用ADAMS软件,对液压系统压力提高后（由16MPa提高到20MPa）装载机液压系统的性能进行仿真研究,从而预测和估计其系统压力提升后,工作装置的机构与液压系统之间的耦合关系。推导出在水平插入工况和收斗工况下转斗缸、动臂缸油腔压力与外负载力的数学模型。研究成果将为装载机实现液压系统中高压化提供理论基础。     

浅谈发动机拉缸产生的原因及防止措施

简述发动机拉缸的机理，分析造成发动机拉缸的原因，并提出了防止拉缸的措施。     

船舶柴油机气缸套拉缸机理的试验研究

根据模拟试验的相似准则设计磨损试验,研究对船舶航行安全构成严重威胁的异常磨损现象,例如拉缸和咬缸。试验结果表明硬化相的性能和含量与试验所选用的材料耐磨性相一致,且随着载荷的增加,材料发生拉毛的时间呈指数关系下降,本文根据摩擦副三滑磨面接触模型,进而提出摩擦界面温度升高导致粘着以及摩擦副表面的强烈摩擦导致硬化相的碎裂甚至折断等因素是气缸套异常磨损的根本原因,为预防气缸套拉缸或者咬缸提供了理论依据。     

Excavator energy-saving efficiency based on diesel engine cylinder deactivation technology

The hydraulic excavator energy-saving research mainly embodies the following three measures: to improve the performance of diesel engine and hydraulic component, to improve the hydraulic system, and to improve the power matching of diesel-hydraulic system-actuator. Although the above measures have certain energy-saving effect, but because the hydraulic excavator load changes frequently and fluctuates dramatically, so the diesel engine often works in high-speed and light load condition, and the fuel consumption is higher. Therefore, in order to improve the economy of diesel engine in light load, and reduce the fuel consumption of hydraulic excavator, energy management concept is proposed based on diesel engine cylinder deactivation technology. By comparing the universal characteristic under diesel normal and deactivated cylinder condition, the mechanism that fuel consumption can be reduced significantly by adopting cylinder deactivation technology under part of loads condition can be clarified. The simulation models for hydraulic system and diesel engine are established by using AMESim software, and fuel combustion consumption by using cylinder-deactivation-technology is studied through digital simulation approach. In this way, the zone of cylinder deactivation is specified. The testing system for the excavator with this technology is set up based on simulated results, and the results show that the diesel engine can still work at high efficiency with part of loads after adopting this technology; fuel consumption is dropped down to 11% and 13% under economic and heavy-load mode respectively under the condition of driving requirements. The research provides references to the energy-saving study of the hydraulic excavators.     

斗轮机俯仰运动受力分析与方案优化

分析了在斗轮机空载、取料、堆料的三种工况下,俯仰运动液压缸受力状况。针对斗轮机俯仰运动受力特点,提出了斗轮机俯仰液压系统的改进方案,以解决斗轮机臂架振动问题。     

钢球锁紧式液压缸的设计计算

本文针对钢球锁紧式液压缸的设计问题，分析了其受力情况，提出了三个设计条件，即自锁条件；解锁条件；承载条件。根据这三个条件，讨论了设计中的有关问题。