2023年全國碩士研究生考試考研英語一試題真題(含答案詳解+作文范文)_第1頁
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1、<p><b>  附錄A</b></p><p>  Hoist crane metal structure</p><p>  Flows -like in the hoist crane, the majority of tire hoist crane, the crawler crane as well as the partial autohoi

2、st and special-purpose flows -like the hoist crane, all installs has clothes rack the bracket arm, and through lifts using its peak block and tackle installs changes lifts the steel wire position, thus realization heavy

3、item fluctuation; Again changes its height of lift and the working radius through the change clothes rack bracket arm length and the angle of tilt. Therefore, mainten</p><p>  On clothes rack the bracket arm

4、 steel pipe is specially in the welding place, very easy to appear the crack; This must examine carefully, when necessity applies the magnifying glass careful observation. According to we many year experiences, is very s

5、mall when the crater place crack, must carry on the regular track inspection, gazes at the crack closely the development change, in order to take the measure promptly. When crack width as big as 1mm above, should the pro

6、mpt patching. The concrete me</p><p>  When the pit depth achieved the steel pipe the arm thick size, also the pit distortion diameter achieves when 25mm (diameter for 2~5mm) and a straightedge, if the pit p

7、osition in clothes rack on the bracket arm steel pipe surface, then defers to the method which shown in Figure 1 to determine the pit the depth, soon chooses the good steel ball to put in the pit, if the steel ball apex

8、up just could with right angle under along the contact, we be possible to regard the steel ball by now the diame</p><p>  When clothes rack the bracket arm simple root steel pipe surface damage quite is seri

9、ous, should adopt its damage serious section of steel pipes removes, welds section of steel pipes the method to carry on processing, but must add on a section inside the steel pipe to strengthen the steel pipe. Front in

10、order to cause to weld strengthens the steel pipe to be able the smooth insertion to remove in a section of clothes rack bracket arm steel pipe, strengthens the steel pipe to be supposed to make </p><p>  Th

11、is time, 4 steel pipes all must weld, therefore should defer to Figure 4 requests the vehicle to make 4 inside diameters to strengthen the tube, after the inside diameter strengthens wall thickness which the tube turning

12、 remains to be supposed not to be bigger than clothes rack the bracket arm steel pipe thickness, the middle crater slope must be able to satisfy the strength of a weld the need. At the same time, the entire clothes rack

13、bracket arm 4 steel pipe welding position must stagger, ca</p><p>  Welds repairs time must pay attention: Chooses the appropriate welding rod and the material quality reasonable strengthens the steel pipe;

14、Also must pay attention to the ambient temperature in the fall winter season and weld the explanation labor embryo clamping apparatus and so on to entire to weld repairs the quality the influence, as well as the welding

15、circumference welded joint do not have to be vertical with the original steel pipe length direction.</p><p>  The weak clothes rack bracket arm goes against the sheave pintle the wearing capacity to surpass

16、the full size time 5%, namely should replace. When examination, clothes rack the bracket arm will place in a bearing point, will cause to lift the steel wire to relax, the hand will push the pulley if will rock the quant

17、ity to be very big, will have to dismantle with the ruler surveys, otherwise added an oil to be possible.</p><p>  To connects the crown arm festival (lift hook block and tackle), the middle arm festival (ex

18、pands and contracts cylinder fixedly), the foundation arm festival (with turnplate, amplitude cylinder, keeps off cord pulley axis) and so on place to sell the axis also to have to inspect frequently. When its wearing ca

19、pacity achieved when full size 5%, must replace promptly. When inspection, also is places clothes rack the bracket arm in a bearing point, dismantles one, inspects one, again installs one,</p><p>  Inspects

20、the lift hook the mark and guards against escapes installs whether conforms to the requirement, flaws and so on lift hook whether there is crack, stripping; The lift hook cross section wears, the aperture increase, the t

21、orsional deflection, whether exceeds the allowed figure; The lift hook pate and the superficial whether there is weary distortion, the crack and do the correlation sell the axis, the wrap attrition situation. The inspect

22、ion steel wire specification, the model and the pul</p><p>  Brake establishment, brake pattern whether conforms to the design requirement, brake flaws and so on tension bar, spring whether there is weary di

23、stortion, crack; Sells the axis, the spindle, the brake pulley, the brake lining plate whether wears exceeds the allowed figure, hydraulic brake whether oil leak; Applies the brake the gap adjustment, whether brake power

24、 conforms to the requirement. The reel body, does the tube reason whether there is fatigue cracking, damage and so on the situations; </p><p>  Whether the pulley is equipped with guards against escapes the

25、rope trough installment; Pulley rope trough, wheel rim whether has the crack, the ragged edges, the attrition exceeds the allowed figure and so on the conditions, the pulley rotates whether nimbly. The speed reducer move

26、s when whether there is fierce metal fricative, vibration, shell radiation and so on unusual sound; Whether the axial-tab terminal does seal complete, whether the set bolt does have conditions loosely and so on damage<

27、;/p><p><b>  附錄B</b></p><p><b>  起重機金屬結構</b></p><p>  流動式起重機中,大部分輪胎起重機、履帶起重機以及部分汽車起重機和專用流動式起重機,都安裝有桁架臂,并利用其頂端的滑輪組通過起升裝置來改變起升鋼絲繩的位置,從而實現(xiàn)重物的升降;再通過改變桁架臂的長度和傾斜角度來改變

28、其提升高度和工作半徑。因此,保持桁架臂的完好是非常重要的。因為起重機升降重物作業(yè)內(nèi)容的多樣性和各式各樣的作業(yè)環(huán)境,以及起重機駕駛員操作水平的高低等原因(有的還違規(guī)操作),這些都會造成桁架臂不同程度的損傷,甚至折臂或人員傷亡。</p><p>  在桁架臂鋼管上特別是在焊接處,很容易出現(xiàn)裂紋;這要仔細地查看,必要時應用放大鏡仔細觀察。根據(jù)我們多年的經(jīng)驗,在焊口處的裂紋很小時,就要進行定期跟蹤檢查,密切注視裂紋的發(fā)展

29、變化,以便及時采取措施。當裂紋的寬度大到1mm以上時,就應及時補焊。具體的方法是,先對裂紋處的原焊口進行打磨,去掉多少則視具體情況而定;然后進行補焊;最后整修好即可。</p><p>  當坑的深度達到鋼管的臂厚尺寸、且坑的變形直徑達到25mm時(直徑為2~5mm)和一把直尺,如果坑的位置在桁架臂鋼管的表面上,即可按照圖1所示的方法測出坑的深度,即將選好的鋼球放入坑中,如果鋼球的上頂點剛好能與直角的下邊沿接觸,這

30、時我們就可以視鋼球的直徑為坑的深度。如果坑的位置在鋼管的側面或下面,可先用黃油將鋼球粘住后再進行測量。對這種維護的損傷,可用一般材質(zhì)與原鋼管相同的鋼管焊接加固,即取一段鋼管沿中心線分成兩半,將其端部修成斜面,已免焊口垂直于桁架臂鋼管的長度方向。在焊前須將原桁架臂鋼管上面待焊處的涂漆打磨干凈,做好焊前準備。</p><p>  當桁架臂單根鋼管表面的損傷比較嚴重時,應該采取將其損傷嚴重的一段鋼管去掉、重新焊上一段鋼

31、管的方法進行處理,但在鋼管里面必須加上一段加強鋼管。為使焊前加強鋼管能順利的插入已去掉一段的桁架臂鋼管內(nèi),加強鋼管應做成同樣長的兩段,并先后采用螺紋和焊接兩種方式進行連接。加強鋼管L1和L2的長度須比桁架臂鋼管去掉的一段短20mm,且其外徑應比桁架臂鋼管的內(nèi)徑小20~40μm,以使加強鋼管在桁架臂鋼管內(nèi)既可以移動又不再松動。先將加強鋼管L1和L2分別插入桁架臂鋼管內(nèi),并將它們用螺紋連接起不來,然后擰緊使兩軸肩靠嚴,持找準加強鋼管所在位置

32、后,分別將其螺口處在位置后,分別將其螺口處和兩頭焊牢既可。桁架臂鋼管的焊口要做成斜面,與其鋼管軸線垂線夾角為10°~30°之間,如損傷的為多根鋼管時,應選擇10°。至此,再認真測量桁架臂鋼管焊好后的實際缺口尺寸,下一段鋼管料,兩端做成30斜面,沿中間剖開焊接在桁架臂鋼管的缺口上;最后修整,涂漆即可。</p><p>  此時,4根鋼管都要重新焊接,因此應按照圖4的要求車制4根內(nèi)徑加強

33、管,內(nèi)徑加強管車削后所剩的壁厚應不大于桁架臂鋼管的厚度,中間的焊口坡度要能滿足焊接強度的需要。同時,整個桁架臂4根鋼管地焊接位置要錯開,不能在同一個橫截面上,且每根鋼管的焊口于其軸線垂線的夾角應為10°。</p><p>  焊修時須注意:選擇合適的焊條和材質(zhì)合理的加強鋼管;在秋冬季節(jié)還要注意環(huán)境溫度及焊解釋工胎卡具等對整個焊修質(zhì)量的影響,以及焊接的圓周焊縫不要和原鋼管的長度方向垂直。弱桁架臂頂上滑輪軸

34、的磨損量超過原尺寸的5%時,即應更換。檢驗時,將桁架臂放在一個支承點上,使起升鋼絲繩放松,手推滑輪如果晃動量很大,就須拆下用尺來測量,否則加些油就可以了。對連接頂部臂節(jié)(吊鉤滑輪組)、中間臂節(jié)(伸縮缸固定)、基礎臂節(jié)(與轉(zhuǎn)臺、變幅缸、擋繩滑輪軸)等處的銷軸也要經(jīng)常檢查。當其磨損量達到原尺寸的5%時,須及時更換。檢查時,也是將桁架臂放在一個支承點上,拆下一根,檢查一根,再安裝一根,逐根檢查,直至檢查完畢。</p><p

35、>  檢查吊鉤的標記和防脫裝置是否符合要求,吊鉤有無裂紋、剝裂等缺陷;吊鉤斷面磨損、開口度的增加量、扭轉(zhuǎn)變形,是否超標;吊鉤頸部及表面有無疲勞變形、裂紋及相關銷軸、套磨損情況。檢查鋼絲繩規(guī)格、型號與滑輪卷筒匹配是否符合設計要求。鋼絲繩固定端的壓板、繩卡、契塊等鋼絲繩固定裝置是否符合要求。鋼絲繩的磨損、斷絲、扭結、壓扁、彎折、斷股、腐蝕等是否超標?! ≈苿悠鞯脑O置,制動器的型式是否符合設計要求,制動器的拉桿、彈簧有無疲勞變形、裂紋

36、等缺陷;銷軸、心軸、制動輪、制動摩擦片是否磨損超標,液壓制動是否漏油;制動間隙調(diào)整、制動能力能否符合要求。卷筒體、筒緣有無疲勞裂紋、破損等情況;繩槽與筒壁磨損是否超標;卷筒輪緣高度與鋼絲繩纏繞層數(shù)能否相匹配;導繩器、排繩器工作情況是否符合要求。  滑輪是否設有防脫繩槽裝置;滑輪繩槽、輪緣是否有裂紋、破邊、磨損超標等狀況,滑輪轉(zhuǎn)動是否靈活。減速機運行時有無劇烈金屬摩擦聲、振動、殼體輻射等異常聲音;軸端是否密封完好,固定螺栓是否松動有缺損

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