ZL120型整体动臂装载机设计【毕业设计装载机设计】【含CAD图纸】
设计 ZL120型整体动臂装载机设计,学生姓名: 指导教师:,(课题来源: ),装载机,装载机属于铲土运输机械类,是一种通过安装在前端一个完整的铲斗支承结构和连杆,随机器向前运动进行装载或挖掘,以及提升、运输和卸载的自行式履带或轮胎机械。 它是工程机械中不可缺少的装备之一。,装载机的分类,1) 按行走装置不同可分为履带式和轮胎式两种。右图是一种履带式装载机。这种装载机坚固耐用、与地面附着力大、接地比压力小、越障碍物能力强,但其质量大、运动惯性大、结构复杂、磨损严重、维修量大、运行速度受限制,而且不能起吸收振动和缓和冲击的作用。,右上图是一种轮式装载机。这种机型采用双臂支承铲斗,铲斗工作平稳性好,受力状况也较好,但两臂之间有一定尺寸,这导致结构尺寸扩大,可能与轮胎等发生干涉,结构不好布置。 右下图也是一种轮胎式装载机。这种机型采用单臂支承铲斗,铲斗工作平稳性及受力状况均不如双臂支承,但此型式结构紧凑,结构易与布置。,2)按装载方式不同分类按装载方式不同可分为前卸式、后卸式、侧卸式和回转式。轮式装载机基本上都是采用前卸式。 3)按转向方式不同分类按转向方式不同可分为整体式和铰接式。 4)按使用场合不同分类按使用场合不同分为露天用装载机和井下用装载机。 此外,还有一些分类方式。如按传动形式不同可分为机械传动、液压传动、电传动等。,主要设计参数:,1)斗容量4 m3 ; 2)额定载重量80kN; 3)发动机功率200kW; 4)最大掘起力210kN; 5)最大卸载高度3500mm;6)动臂提升时间6.5s; 7)三项和时间12s; 8)最大转向角35; 9)最小转弯半径6800mm;10)行驶速度:前进第4挡36km/h;后退第3挡 20km/h; 11)后桥摆动角10; 12)外形尺寸850032003450mm 13)整机质量18500kg。,装载机总体设计,装载机的总体布置应从保证其主要性能出发,在总体设计和各总成部件设计的密切配合下,根据使用要求和桥荷分配来协调各总成的性能 ,并确定和控制它们的位置、尺寸和重量。总体布置不仅应使装载机具有良好的使用性能,而且必须保证操作轻便、拆装容易和维修方便。,1)车架连接和传动轴的布置 铰接车架铰销中心布置在前后桥轴线中间偏前位置 。 如右图所示,采 用这种布置方式, 装载机转弯时, 前轮转弯半径大 于后轮转弯半径, 作业阻力增大, 作业效率低,操 作性能不好。, 铰接销布置在前后桥轴线的中心。如右图所示,采用 这种布置方式,装载 机转弯时,前后轮轨 迹相同,这不仅在松 软地面上可以减小转向阻力矩和行驶阻力, 而且前轮能通过狭小的 场地,后轮也能顺利通 过,司机操作性能好, 但是这种布置方式就整 个传动系统来说,排列 比较困难。,传动轴布置在装载机的纵向对称平面内,并尽可能成水平布置,使中间传动轴的中点和车架的铰接销中心线重合,这样才能保证转向时,万向节作等速转动。 2)工作装置的布置工作装置布置在装载机的前部,工作装置各构件的布置主要是确定动臂的长度和各铰接点的位置。动臂和车架连接的铰接点的位置,应不影响驾驶员的视线。铰接点前后位置选取时,若铰接点位置前移,卸载的距离增大,稳定性降低。因此,在不影响卸载距离的条件下,尽可能向后布置。,轮式装载机工作装置设计,轮式装载机工作装置 由铲斗、连杆、摇臂、 动臂、转斗油缸、举升 油缸组成。 如图,1为摇臂,2为 动臂,3为铲斗, 4为 连杆。,轮式装载机工作过程,轮式装载机是一种铲、装、运、卸一体化的自行式设备,它的工作过程由六种工况组成。 1)插入工况 动臂下放,铲斗放置于地面,斗尖触地,斗底板与地面呈35倾角,开动装载机,铲斗借助机器的牵引力插入料堆。 2)铲装工况 铲斗插入料堆后,转动铲斗铲取物料,待铲斗口翻至近似水平为止。,3)重载运输工况 铲斗铲装满物料后举升动臂,将铲斗举升至运输位置,然后驱动机器驶向卸载点。 4)举升工况 保持转斗缸长度不变,操纵举升缸,将动臂举升至上限位置,准备卸载。 5)卸载工况 在卸载点,在举升工况下操纵转斗油缸使铲斗翻转,向运输车辆中卸载,铲斗物料卸净后下放动臂,使铲斗恢复至运输位置。 6)空载运输工况 卸载结束后,装载机由卸载点空载返回装载点。,工作装置设计要求:要具有较强的工作能力,铲斗插入料堆的阻力要小,在料堆中铲掘的能力大,能耗低。工作机构的各杆件受力状态良好,强度寿命合理。要保证必要的卸载角、卸载高度。轮式装载机工作机构属于连杆机构,设计中要特别注意防止各个工况出现构件相互干扰、“死点”、“自锁”和“机构撕裂”等现象 。,连杆系统设计,连杆系统有以下几种类型:1)正转八杆机构 2)转斗油缸后置式反转六杆机构 3)转斗油缸后置式正转六杆机构4)正转四杆机构 5)转斗油缸前置式正转六杆机构 6)正转五杆机构 综合考虑各种机构的优缺点,本次设计选用转斗油缸后置式反转六杆机构。,机构分析,右图所示装载机采用反转六杆机构。反转六杆机构由转斗机构和动臂举升机构两个部分组成。转斗机构由转斗油缸、摇臂、连杆、铲斗、动臂和机架六个构件组成。举升机构主要由动臂举升油缸和动臂组成。,根据要求,采用 图解法作图,得到 反转六杆机构如图。在此数据的基础 上,可设计出各构 件。 各构件如图所示,摇臂,连杆,动臂,铲斗,动臂实体网格图,动臂应力分析图,动臂静态位移图,工作装置设计完之后,则可画出底座,完成 装载机总图,如下。,结论,经过三个月的忙碌,毕业设计至今已基本完成。在这段时间里,主要完成了以下工作。查阅各种资料,详细了解了装载机的现状及发展趋势、用途、分类、基本组成等相关知识。在此基础上,完成了装载机的总体设计及工作装置设计,工作装置结构分析与校核以及整机稳定性验算。绘出图纸折合0号图5张,设计计算书40余页, 外文资料翻译5000余字。,所设计装载机的特点:1、国内现有的轮式装载机大部分都是采用双臂结构,而此次设计的装载机则是采用整体动臂结构。2、工作装置选用反转六杆机构。,谢谢各位老师参加我的答辩,敬请老师提出宝贵意见,谢谢!,0毕业设计(论文)任务书题目 ZL120 型整体动臂装载机设计专业 学号 姓名 主要内容、技术参数、基本要求、主要参考资料等:1、主要内容整体动臂装载机总体设计;整体动臂装载机的工作装置设计;工作装置的结构分析;整机稳定性验算。2、技术参数1) 、斗容量 4 m3;2) 、额定载重量 80kN;3) 、发动机功率 200kW;4) 、最大掘起力 210kN;5) 、最大卸载高度 3500mm;6) 、动臂提升时间 6.5s;7) 、三项和时间 12s;8) 、最大转向角 35;9) 、最小转弯半径 6800mm;10) 、行驶速度:前进第 4 挡 36km/h;后退第 3 挡 20km/h;11) 、后桥摆动角 10;12) 、外形尺寸 850032003450mm13) 、整机质量 18500kg。3、基本要求设计机器总体、铲斗图、动臂机构图、主要零件图、机器立体图等,折合 0号图纸 5 张;设计计算书 40 页;外文资料翻译 5000 字。4、主要参考资料相关三维设计与仿真软件及参考书籍;相关机械设计手册、液压手册、网上期刊文献、相关样本等。完成期限: 4 月 9 日6 月 26 日 指导教师签名: 专业负责人签名:年 4 月 3 日 学生开题报告表课题名称 ZL120 型整体动臂装载机设计课题来源 课题类型 A 指导教师姓名学生姓名 学 号 专 业 机自1、调研准备拿到课题,通过查阅资料及实际调查,对装载机有了一定的认识。装载机属于铲土运输机械类,是一种通过安装在前端一个完整的铲斗支承结构和连杆,随机器向前运动进行装载或挖掘,以及提升、运输和卸载的自行式履带或轮胎机械。它广泛用于公路、铁路、建筑、水电、港口和矿山等工程建设。装载机具有作业速度快、效率高、机动性好、操作轻便等优点,因此成为工程建设中土石方施工的主要机种之一,对于加快工程建设速度,减轻劳动强度,提高工程质量,降低工程成本都发挥着重要的作用,是现代机械化施工中不可缺少的装备之一。装载机按行走方式不同可分为轮胎式和履带式装载机;按使用场合不同可分为露天用装载机和井下用装载机;按传动形式不同可为机械传动、液力机械传动、液压传动和电传动四种;按装载方式不同可分为前卸式、后卸式、侧卸式和回转式。轮式装载机基本上都是采用前卸式。按转向方式不同可分为整体式和铰接式。整体式利用偏转后轮或前轮转向,或者同时偏转前后轮,铰接式采用铰接车架,利用前后车架之间的相对偏转进行转向。标志装载机的主要技术性能参数有铲斗容量、额定载重量、发动机额定功率、整机质量、最大行驶速度、最小转弯半径、最大牵引力、最大掘起力、最大卸载高度、卸载距离、工作装置动作三项和等。与此同时,我还特意上施工现场仔细观察和研究了几种型式的轮式装载机,对其基本结构、特点、原理等都有了一个大概的了解,对其各部件的布置、工作过程也有了一个直观的印象,这给设计准备了一定的基础。2、设计目的本次毕业设计设计一个装载机,我想设计目的主要有以下几点:1) 、通过这次设计,熟练地掌握使用 solidworks 软件,这是一大块,需要花一定的时间。2) 、自己通过设计一个整机,对设计过程、思路、协调分配时间等等都是一个锻炼。3) 、通过这次训练,达到巩固以前所学知识,又学习新知识的目的,为以后工作或学习打下坚实的基础。3、设计要求 本次设计要求完成装载机总体图、铲斗图、动臂机构图、主要零件图、装载机立体图等,同时要完成设计计算书 40 页,外文资料翻译 5000 字。所有图纸及计算数据都应正确合理。4、设计思路此次毕业设计要求设计一台装载机,但装载机是一个庞大的复杂机器,以我现在的水平,要想在 3 个月毕业设计期间完成所有的设计,无疑是完成不了的。因此,设计时就有主次之分了。装载机主要是用来装载工作的,而工作机构是其完成工作任务的关键部位,因此,设计的主体就应该是设计工作机构,即设计完成铲斗的动作。而其它部分可参照同类装载机画出。设计思路具体如下:1)进行装载机总体设计。装载机是由许多主要部件组合起来的一个有机整体,其整机性能不仅取决于每个部件的品质,而且主要取决于各部件之间的相互协调,这种相互协调是通过总体设计实现的,所以装载机的总体设计对它的整机性能起决定性作用。总体设计的内容包括装载机总体参数的确定、装载机的总体布置等。这个过程要对装载机的整体形状,各部件形状大小及位置布置等有个清晰的把握,力求做到结构合理,布置得当。总体设计完后,先快速将底座画出,将各部件如驾驶室等布置上去,完成底座。2)进行工作装置设计。装载机工作装置主要由铲斗和支持铲斗进行装载作业的连杆系统组成,依靠这套装置装载机可以对汽车、火车等进行散料装载作业,也可以对散料进行短途运输作业,还可以进行平地修路等作业。装载机工作装置的结构和性能直接影响整机的工作尺寸和性能参数,因此,工作装置的合理性直接影响装载机的生产效率、工作负荷、动力与运动特性、不同工况下的作业效果、工作循环的时间、外形尺寸和发动机功率等。所设计的装载机应具有较强的工作能力,铲斗插入料堆的阻力要小,在料堆中铲掘的能力大,能耗低。工作机构的各杆件受力状态良好,强度寿命合理。结构和工作尺寸适应生产条件需要,效率高。结构简单紧凑,制造及维修容易,操纵使用方便。同时,工作装置设计是本次毕业设计的主要设计内容,因此,必须花大力气,下苦功夫,努力完成,达到设计目的要求。3)工作装置的结构分析。工作装置设计完成之后,其工作是否合理,是否发生干涉,强度是否符合要求等等都需要检验。因此,要对其进行结构分析。主要包括工作装置静力学计算及强度校合,工作装置结构动力分析等。4)整机稳定性验算。装载机设计完成之后,应对其稳定性进行验算。装载机的稳定性是指装载机在行驶过程中,不发生倾履和侧滑的能力。设计出来的装载机应保证其能工作稳定。5、预期成果。设计的预期成果是设计出来的装载机总体方案合理,工作安全可靠且能很好地完成任务要求。6、阶段内容及时间安排1)收集查阅资料:第 1 周;2)设计总体方案:第 2-3 周;3)完成底座图:第 4 周;4)设计工作机构:第 5-7 周;5)检查完善底座及工作机构设计:第 8 周;6)完成装配图及各零件图,并进行分析:第 9-10 周;7)查缺补漏,完善设计:第 11 周;8)完成整理毕业论文及日志:第 12 周;9)准备答辩:第 13 周。7、设计条件此次毕业设计采用计算机绘图,备有计算机一台,相关三维设计及仿真软件如 solidworks 等,并备有机械设计手册、液压手册及轮式装载机等参考资料。指导教师签名: 日期:1、课题来源:课题来源分为结合实际课题和自拟课题两种,结合实际课题中来源于科研课题的要填写确切基金项目、企事业单位项目,不能写横向、纵向课题等。2、课题类型:A工程设计;B科学实验;C软件开发;D理论研究;E应用研究。WHEEL LOADERSCoal International January/February 2001Copyright 2001. All right reserved.16WHEEL LOADERSWorkhorses of the industry,with larger units adding flexibility to surface coal mining operations and smaller machines invaluable in stock-pile work,rehandling and other tasks The primary choices today for open pit coal and overburden excavation and loading are between electric cable shovels,hydraulic excavators and wheel loadersWheel loaders carry 18-21% of their operating weight as payload,compared with 5-7% for electric cable shovels and 8- 11%for hydraulic face shovelsBy fitting the bucket close to the carrier,designers of wheel loaders create a very favorable payload-to-operating weight ratio,allowing mobility around a mineWith comparably sized buckets,an electric shovel will weigh something like four times as much as a wheel loader,while a hydraulic face shovel,might weigh about twice as much as a wheel loader for the equivalent bucket capacityElectric shovels can be expected to routinely achieve economic lives of 75,000-100,000 hours,with documented long-term operating costs in the range of $ 0060-0095/tonneHydraulic shovels and wheel loaders are generally considered to have economic lives in the 30,000-60,000 hour range They work in a wide range of conditions so their long-term operating costs are in a broader range of $ 00080-0140/tonneIt should be noted that these long-term comparisons assume that costs are spread over the entire economic lives of the machinesIt should also be remembered that the purchase of wheel loaders and hydraulic shovels could generally be considered to be reversible decisionsAt almost any point in their working lives,they can be fairly easily resold and moved without a severe cost penaltyThe same is unlikely to be true of electric shovelsIn practice,it is unlikely that a mines choice would be between a wheel loader and an electric shovelA more likely decision would be to make the choice between hydraulic excavators and wheel loadersChoosing between these two options can have significant effects on truck maintenance costsFor example,controlled dumping of material into the truck has a great influenceDumping heavy boulders into an empty truck can cause damageHowever ,a hydraulic excavator WHEEL LOADERSCoal International January/February 2001Copyright 2001. All right reserved.17equipped with a bottom dump bucket can ensure a certain amount of dampening of the fall of the material into the truck by opening the bucket only slightly so as to allow smaller rocks to fall first and form a buffer for the larger,heavier bouldersReach and dump heights also play a considerable role in truck repair costsA machine with a long reach greatly reduces and even eliminates the risk damage to tyre walls Furthermore the better suited the dump height of the loading tool is to the truck, the lower the risk of damage to the trucks side wallIn the case of the wheel loader, the use of high lift versions can compensate somewhat for thisHowever ,a wheel loader will always,essentially ,be nearer to the truck during the dump phaseVersatility and mobility are other important considerationsIn one minute a cable shovel will travel about 21 meters, a hydraulic shovel about 37 meters and a wheel loader about 370 metersMobility is a key factor in choosing wheel loaders,especially with large new models capable of producing in the 3,000-3,500 tonne/hour,range,and moreBlending,multiple faces and shove1 backup are all functions that can be performed well due to the wheel loaders mobilityHowever,a drawback to the mobility advantage of the wheel loader is its need for relatively smooth,flat floors,to prolong tyre life and provide machine stabilityHowever ,those smooth,flat floors in the loading area are needed anyway,unless the mine is prepared to pay severely for damage to expensive truck tyres as they roll onto the loading areaThe method of digging is different for all three machinesBecause the cutting edge does not change angle on an electric cable shovel bucket,loading is accomplished by raking the face in a long sweeping arc rather than biting into it by combining boom,stick and bucket forces (as with hydraulic excavators),or by combining power train,bucket crowd and rack back forces (as with wheel loaders)A hydraulic shovel is considered a selective excavating tool and a wheel loader is considered a loading toolThis is because,due to geometry,a hydraulic excavator can apply its breakout force over its reach of the face,while a wheel loaders best digging occurs low-from the toe of the face to about the height of the loaders bucketWheel loaders can get the best bucket fill factors in production rock face conditions,if used properlyBoth they and hydraulic backhoes should achieve 100% (more with some wheel loaders),compared with 90-100% for electric shovels and 80-85% for hydraulic face shovelsWHEEL LOADERSCoal International January/February 2001Copyright 2001. All right reserved.18A survey in the 1990s undertaken by Caterpillar of midsize wheel loaders provided an interesting insight into the factors involved in machine purchase decisionsThe considerations brought into play,in descending order of priority were: Performs tasks well Can trust to run Easy to operate Easy to maintain Lasts long time Operator comfort Competitive price Repair cost low Versatility Good resale value Fuel consumption Easily transported Design appearance Today,with fuel costs rising,we might expect to see fuel consumption having a higher priority The operating conditions that favor the selection of wheel loaders include Mobility Versatility Low pile profile Smooth floorWHEEL LOADERSCoal International January/February 2001Copyright 2001. All right reserved.19 Level floor Load-and-carry Shop maintenanceWhy wheel loaders?In summary then,if wheel loaders have been selected as the primary loading tools, each unit should be capable of loading a truck in three to four passesThe cycle time per pass should be between 30 and 35 secondsThe loader should also achieve a 75-85% bucket fill factor in a single pass when loading blasted rock and 100% or more in rock-dirt mixturesThe ability of the chosen machine to achieve these performance criteria will be influenced by the loaders performance features and it is important to check that the machine has a high full-turn static top load capability,a high breakout force and fast hydraulic cycle timesThe dump height clearance and forward reach of the loader should be compared with the truck side board height and body widthWheel loaders are very mobile and are ideally suited to applications that demand selective mining and require the loader and haul trucks to move between various loading sitesIt should,however ,be borne in mind that the loader tyres can become a high cost item and care should be taken to protect these as far as possibleHowever ,wheel loaders can provide their own clean-up support in the loading area,where requiredThe big onesHigh capacity wheel loaders are not new to the industry,LeTourneau has pioneered such machines for many yearsAs far back as 1982,at the Las Vegas American Mining Congress,Marathon launched its L-1000 diesel-powered and TCL-1000 training cable wheel loaders; both equipped with 13 cubic meter buckets as standard Clark Michigan,now part of the Volvo Construction Equipment group, also offered a large capacity wheel loader many years agoMore recently,both Caterpillar and Komatsu have launched monster unitsLeTourneau is the specialist,offering all-wheel; electric drive wheel loaders based on concepts initially explored by founder RGLeTourneau back in 1923The technology has been proven since 1950 and refinements since have included traction proportioning WHEEL LOADERSCoal International January/February 2001Copyright 2001. All right reserved.20that minimizes wheel slip and tyre wear by allocating power to the wheels that gripThe company claims still to be the only manufacturer of wheel loaders offering all-wheel drive,which,LeTourneau reports, “improves stability and increases operator comfort”If LeTourneau has long been the major proponent of the large wheel loader,it was perhaps a Caterpillar development that got such machines widely acceptedA major milestone and a catalyst that led to much more widespread use of large wheel loaders was Caterpillars launch of the 994 back in late 1990That was also a significant milestone in Cats programme of development of large mining machines which has seen the company take the mining world by storm,particularly in large trucksCaterpillar has certainly proved that the mining industry is interested in large wheel loadersIts first 994 went into operation at the Cyprus Sierrita open-pit copper mine in Arizona in November 1992,over 50 such units had been sold,and the first 12 had logged over 100000 operating hoursAnnouncing this at the Las Vegas American Mining Congress in1992,the manager of Caterpillars Mining Vehicle center,Don Hopkins,admitted that this volume of sales was higher than expectedThat first 994 was a high-lift model equipped with a 16 cubic meters bucket,though buckets up to 31 cubic meters wear available depending on application The 994 was then the largest mechanical drive wheel loader available in the worldThe largest electric drive machine was a LeTourneau,as it is todayBut today,the largest mechanical drive honor goes to Komatsu with the WA1200-3Traditionally the much greater mobility of wheel loaders allows their use in secondary loading applications in very large open pitsThey are also widely used in smaller operations such as eastern US coal mines and medium to smaller gold minesBut the large wheel loader has really taken off and a growing number of these machines are being put to heavy-duty loading requirements,especially in North America,Australia and selective markets in Latin America and elsewhereThe smaller units with bucket capacities of 10 to15 cubic meters are used only with the smaller truck sizes,but Komataus WA1200, Cats 994 and the bigger LeTourneaus can be matched with all but the very largest trucksThere are still only a few big mines that rely on these bigger wheel loaders completely However,several hundred such machines are now working alongside,or in place of , electric and hydraulic shovelsWHEEL LOADERSCoal International January/February 2001Copyright 2001. All right reserved.21By the time Caterpillar had achieved sales of well over 220 994s around the world, representing around 60% of all large wheel loader sales,it released the 994DSignificant among the technology updates were Cats Steering and Transmission Integrated Control (STIC) system that combines gear selection and steering into one control lever that requires less effort and makes shifting smootherCaterpillar reports that this allows up to 10% greater productivityA number of older machines were retrofitted before the 994 launch and displayed anything from 7 to 12% greater productivity in field trialsRetrofits are available for all 994s already operatingThe rim pull control with new left-pedal operation also is importantThis allows the operator to match rim pull to conditions for improved tyre life,loadability and increased controlOperator comfort is becoming more and more importantIn the 994D,the new seven-way Contour Series air-suspension seat lets the operator adjust his or her seat to precisely the right position,optimizing movements and experiencing less fatigue over the shiftThe 994Ds payload has been increased to 345 tonne for standard models and 31 tonne for the high-lift arrangementBucket capacities can be 14 to 31 cubic meters The 994D should load 2800-3000 tonnes per hour and achieve a tyre life of 5000-6000 hoursLeTourneaus monsters LeTourneaus designers have been busy recentlyFirst the company announced the L-1350 loader in 1999,with deliveries beginning in 2000,and then at MINExpo in Las Vegas last October,LeTourneau exhibited the monster L-2350The 1120KW L-1350 has a 20cubic meter bucket capacity,66 meter lift height,and 29 meter reachIt rides on 49/75-51 tyres and has been specifically designed to minimize loading costs for 136 to 181 tonne capacity trucks and has the capability to load many of the 218 tonne capacity unitsMany of the major components incorporated on the loader have already been field proven on the other LeTourneau loader modelsAt the time of its launch,LeTourneau said the introduction of the L-1350 would strengthen its position “as the market leader in high-performance,cost effective front-end loaders ”The new 1715 kW LeTourneau L-2350 wheel loader,with a standard 405 cubic meter bucket capacity,a 73 meter lift height and 38 meter reach,is now,clearly ,the worlds largest wheel loaderThe L-2350,like the L-1350,is WHEEL LOADERSCoal International January/February 2001Copyright 2001. All right reserved.22controlled and monitored by the LeTourneau Integrated Network Control System (LINCS),which provides the most intelligent computerization available,LeTouneau claimsThe information it provides includes bucket weights,cycle times,preventative maintenance data,self-diagnostics and moreLINCS manages all loader systems (including hydraulics,electrics,traction drive and engine) through the interactions of the Master System Manager (MCM) and multiple Remote Control Modules (RCMs)The MCM combines ruggedised industrial hardware with a Pentium class microprocessor to direct the entire system from the cabThe RCMs are distributed around the machine providing the MCM with the hands and eyes needed to control and monitor the machineThe MCM is located in the cab of the loaderIt has more than 350 input/output points and the ability to store more than a months worth of operating and production dataThe RCMs use a high-speed 30-bit processor and connect directly to sensors,drive outputs and operator controlsThey are housed in environmentally sealed enclosures,designed to withstand high-pressure hot water washes and drenching in any vehicle fluidsOther features include reliable gold-to-gold connections and short circuit and reverse polarity immunityThese EMC tested modules automatically programme themselves to the needs of the locationThus they operate on a quick pull-out/plug-in procedureAmong the advances is that the second reduction gear is centre-hung between two bearings with a splined interface between this gear and the middle pinionThis design change results in more equal load share between the middle pinion and the three reduction counter-shaft gearsBetter load share results in lower shaft and gear stress at the third and fourth reductionsThe splined interface enables the middle pinion to be removed so that the loader can continue to run if a motor is disabledIn addition,the middle pinion can be replaced if the other driver gearing is in good conditionBoth operations can be accomplished without removing the driver from the machine LeTourneaus proven taper lock design and a unique timing method further ensure equal load shareThe driver ratio minimizes the required motor torque while simultaneously minimizing the shock loads at the counter-shaft pinionBefore the L-2350,LeTourneaus L-1800 was the largest wheel loader in the world, with a capacity of 454 tonne and able to centre-load trucks of 270 tonne capacity and largerThe L-1800 is offered with a 1342 or 1491 kW engine and,in WHEEL LOADERSCoal International January/February 2001Copyright 2001. All right reserved.23keeping with the trend to longer service intervals,its self-cleaning KLENZ air filtration system reduces maintenance costs and improves reliabilityIt can lift loads up to 50 tonneOther features include full helical gearing in the final drive units and a cab designed for better operator comfort and visibility,enhanced by the machines sloped design which provides a superior rear viewThere is an L-1800 at work at Triton Coals North Rochelle coal mine in Wyomings Powder River Basin (the proving ground for so many of todays largest earthmovers) in the early stages of North Rochelles development (opened in December 1998) Its narrow pits required manoeuvrability and this was ably supplied by the L-1800 with its 134 meter turning radius in high-lift configuration Mobility is one of the reasons the mine purchased this loaderThe other was capacity Bucket capacities can be up to 42 cubic meters for coal mining and North Rochelle chose a 34-cubic-meter combo bucket to load both coal and overburden Its 73-meter dump clearance allows it to load 218 tonne capacity trucks with easeThe worlds biggest mechanical drive loader today,Komatsus WA1200-3,is powered by Komatsus SDA16V160 electric-controlled engineIts standard 163 cubic meter bucket will load 216 tonne trucks in just six passesIts modulated clutch system offers adjustable travel speed,traction control and tyre specification settings for multiple applicationsThe Precise Dial Control of Travel Speed setting offers the operator variable travel speeds for tight V cycles decreasing cycle times and increasing digging capabilities and tyre lifeThe Traction Control setting features a traction power selection of 20 to 100% to accommodate various application conditionsThe Tire Saver setting controls tyre slip,preventing wear and prolonging tyre lifeThe WA1200-3 features the Remote Boom PositionerThis allows the operator to set maximum and minimum bucket positions, promoting smooth component movement and preventing spillageThe Variable Output Hydraulic System(VOHS) is a self-adjusting hydraulic system that reduces oil consumption and increases tractive effort and saves fuelIn addition,a new 65/65-67-62PR ultra-wide tyre with additional rubber on the ground and increased air volume is now availableAs any good earthmover today,the WA1200-3 is designed for easy maintenance and service To minimize maintenance and downtime the machine is equipped with a Vehicle Health Monitoring System (VHMS),an integrated WHEEL LOADERSCoal International January/February 2001Copyright 2001. All right reserved.24maintenance system that employs self-contained diagnostics,a preventive maintenance scheduler and machine performance historyCaterpillar brought about a radical change in wheel loader design in 1997 when it launched the 992GThe 992 wheel loader has long been a workhorse of the mining industry,and widely used in stockpilingThe 992G began an innovative concept,the cast box section boom,the first major change in wheel loader design in about 20 yearsThis increases dump clearance, improves bucket visibility and requires no maintenance It also offers three times the tortional strength of a traditional design,according to CaterpillarCompared with previous models,Caterpillar reports a 15-20% increase in productivity from the 597 kw 992G,payload raised by 7%,and cycle times cut by 10% Cab sound levels have been reduced and daily service costs cut by about 20% This 91.8 toone unit can be equipped with 11.5 to 12.3-cubic-meter buckets and features a dump heignt of just over 4.6 meters and a reach of 2.3 metersIt will four-pass load a 90 toone payload 777D truck (around 2000 toones/hour) in the high reach versionCaterpillars testing of the machine showed that in truck loading it is 43% more productive than the 992C in coal operations
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