外文翻譯--淺談帶式輸送機(jī)的拉緊裝置

1、<p><b>　　附錄A</b></p><p>　　Discussion about pull installation of belt conveyer</p><p>　　Belt conveyer also claimed rubber belt conveyor, which is called " leather belt "

2、; in the Produce scene, is the continuous facility for transporting of the common enter- prise of factories and mines. It is widely used under the well of coal mine, particularly extensively. The major parts of belt conv

3、eyer include conveyer belt, actuating device, bearing roller, cylinder, frame, tension station, brake, supplementary equipment as well as electromechanical protective device and so on. When designing </p><p>

4、;　?。?）Guarantee conveyer belt’s split of driving pulley have proper tension in order to prevent conveyer belt from dozening slippery. </p><p>　　Belt conveyer depend on the friction between support conveyer b

5、elt and driveing pulley, in appearance meet with split to produce a tension haulage of system. Therefore to make belt conveyer stabilize operation need to guarantee conveyer belt have enough tension in driveing pulley s

6、plit place, in order to make conveyer belt rely on , with the friction of cylinder, transmiting the haulage needed by system. If split place has little tension, the friction haulage that conveyer belt transmits can't

7、 </p><p>　　(2) Guarantee having necessary tension each on the girth of conveyer belt so as satisfy sag requirement. </p><p>　　Conveyer belt’s sag between two bearing rollers should not be except

8、ional , otherwise conveyer belt would relax excessly to lose groove shape cause the sideslip of conveyer belt , arouse spillage , increase operation resistance. Therefore automatic tension station should guarantee that c

9、onveyer belt has enough tension in the minimum tension place in order to restrict sag between bearing rollers on conveyer belt, keep belt conveyer’s steady operation. </p><p>　　(3)The regulation of tension

10、in the not steady working condition of start , brake etc. </p><p>　　In the course of starting, because of acceleration sport of belt conveyer, the haulage that conveyer belt need to transmit bigger than stea

11、dy operation much, therefore it has to raise the tension value in the split place of the driveing pulley to produce larger haulage. And in brake course, especially for the conveyer of long distance and big volume, as the

12、 role of force, the tension on the tight side of conveyer belt can reduce , even arouse the tape of layer upon layer probably; Loose side, t</p><p>　　(4) Compensate line viscous elongation and the flexible

13、elongation of conveyer belt.</p><p>　　conveyer belt can automatic elongation as time goniong, and occur permanent elongation under transitional operating mode, , so it is needed to compensate plasticity and

14、the change of elongation in transitional operating mode. Since load change can arouse conveyer belt’slength changing, vermicular phenomenon can also cause the elongation of conveyer belt, and tensile force changes , it h

15、as to regulate the location of tension pulley often , and guarantee the normal operation of belt conveyer. </p><p>　　(5)Offer necessary route for conveyer belt to contact again.</p><p>　　Each b

16、elt conveyer has some joints , possibility in certain contact for a short while can arise problem, must stop first and then make the joint again. Tension station has prepared the belt besides load for belt conveyer, so c

17、ontacting fault can be contacted again through relax tension station to solve problem. For stretch out and draw back allowing belt conveyer, when storing up tape district to store up full tape, we can take out extra conv

18、eyer belt through tension station. </p><p>　　Tension station, for belt conveyer transportation system, has the important role that cannot replace , therefore domestic and international scholar has carried ou

19、t plenty of researches for it , has developed a lot of new products. Its development course can be sumed up approximately for 3 following stages:</p><p>　　First stage is pure mechanical tension stage. The ma

20、jor product of this stage : Spiral tension station and stationary winch tension station and heavey hammer tension station. Heavey hammer tension station reaches the purpose that pulled through pulley groups and heavey ha

21、mmer piece, , when the elongation of gummed belt, it can absorb its elongation voluntarily. The stationary winch tension station’s function of tension is to pull only, when belt elongation tensile force drop because of v

22、arious r</p><p>　　Second stage, the adjustable stage of tensile force. The typical product of this stage is voluntarily winch( mechanical winch or hydraulic winch) tension station. Its technology develop loo

23、ked that it can only realize the automatic tight in steady( even speed) stage, it is constant to maintain the tension of gummed belt in steady stage. And it's tensile force under the instability operating conditionse

24、s such as brake or starting-up is same as the stationary winch identical. It's structural featu</p><p>　　The stage of 3th, development automatic tight stage. Major product has hydraulic winch automatic t

25、ension station and hydraulic automatic tension station of big jar. Such as KJ2029 model which is domestic and international widely used belt conveyer esprcialy used in mines, the hydraulic automatic of big jar tight syst

26、em used in A model belt conveyer produced in French, DYI hydraulic type of big jar tight system, these kinds of automatic tight system can accomplish the voluntarily regulation tensi</p><p>　　Now, the domest

27、ic and international various does not have the unify view for the applicability of tension stations yet, this shows that some conclusions which determines the nature still not perfect ,it is must to have ration con

28、clusion to guide design. Refering to actual use condition, winch tension station and hydraulic tension station can realize automatic control and tensile force is adjustable , heavey hammer tension station has higher rel

29、iability. Along with the development of indus</p><p>　　For the belt conveyer of not large inclination, mostly uses vehicle type pulls which include: pushcart,cylinder ,tension generated equipment and the c

30、ontrol system,tension generated equipment include: heavy hammer, Winch, hydraulic oil cylinder and so on.</p><p>　　The way of the regulation tension of tension station of leather belt can be the tension val

31、ue of constant maintenance; Or maintain the two constant tension values of leather belt ( start tension value and operation tension value ); Or maintain constant tension Proportion . In belt conveyer is systematic to ar

32、range , reasonable definite tension station is to guarantee conveyer normal operation , start and brake safety and reliable as well as the necessity with reasonable economy prerequisite. Th</p><p>　　Tension

33、station can be divided into stationary, heavy hammer type and automatic type 3 kinds according to structural type.</p><p>　　( 1 ) stationary tension station include spiral pull and regular winch pull.</p&

34、gt;<p>　　It is put up that pulls the bearings of pulls cylinder in spiral system to install when move about, moving frame can slide on rail, when revolving screw rod, it is together ongoing to make the nut on mov

35、ing frame follow moving frame with retreat , reach the purpose that pulls and relaxes. Its characteristic is structure simple, but stroke of tension is too little , applies to the conveyer of short distance only, when ge

36、neral captain is smaller than 80 metres, just chooses. </p><p>　　The shortcoming of spiral tension station is: After conveyer belt is used a not long time, as a result of plasticity is deformed, elongation,

37、if havn't prompt adjustment, the tensile force of conveyer belt would reduce , conveyer belt can change loose and arouses conveyer belt to hit, is slippery. Additionally, because of load often change , conveyer belt

38、 receives load impact, the regular bolt that causes tension pulley is loose , screw rod retreats , from this cause the pine of conveyer belt C</p><p>　　Regular winch tension is to pull using small-sized win

39、ch. Winch use worm and worm gear reducer normally to drive reel twine wire rope, in order to pull belt. The advantage of this kind of tension station is: Volume is little , pulling force big, so have been applied extens

40、ively on belt conveyer under the well of coal mine. It's shortcoming is: It can only regulate according to needs, after regulating , produce regular tensile force. When winch arises problem with control system, for b

41、elt conve</p><p>　　Fix winch tight way that can only adjust conveyer belt tight level regularly.Normally, beginning has been in to tight state , makes the conveyer belt bear extra additional load, and in

42、operation course, tensile force Gradually reduces along with permanently change of conveyer belt to increase,and regular appearance gradually to hit slippery phenomenon. Additionally, use regular winch as the tension sta

43、tion of the belt conveyer of long distance, conveyer belt's moveing stress is big for the co</p><p>　　( 2 ) type of heavey hammer tight.Heavy hammer tension equipment ,including one hammer type, multiple

44、 hammers type and hammer vehicle type. The structure of heavy hammer tension equipment is simple , it is applied comparatively extensively, can guarantee tensile force maintenance constant in various operating conditions

45、es, and can absorb and compensate the elongation of conveyer belt voluntarily. Heavy hammer tension equipment pulls conveyer belt through takeing affect wire rope tension pulley ,</p><p>　　( 3 ) automatic p

46、ull.Automatic tension equipment is the type of tension equipment of extensive application in modern conveyer, it make conveyer belt have reasonable tension distribution , and compensates the flexible deformed and plastic

47、ity elongation of conveyer belt voluntarily. Automatic tension equipment twines wire rope normally by winch to pull cylinder, so pull leather belt.</p><p>　　Automatic tension equipment can be divided into el

48、ectric winch tension equipment and hydraulic winch tension equipment according to different forms of driving; according to the change law of a little tension on split point which can be regulated , it can be divided into

49、 steady type , follow to move type and comprehensive type 3 kinds of type. Stabilize type automatic tension station can make split the tension of conveyer belt keep in the sphere of certain error constant, and do not rel

50、y on other</p><p>　　The advantage of automatic winch tension station is known gradually extensively by people, but also exist a lot of shortcomings. Electric winch tension station is to use tension sensor in

51、 order to feedback , adjusts the size of tensile force voluntarily according to the different operating conditions of belt conveyer , has not high quality by tension sensor or mechanical systematic inertia and the influe

52、nces such as signal hysteresis and automatic winch have misoperation phenomenon , affect it t</p><p>　　In actual application, will first calculate haulage reasonably according to the working condition of bel

53、t conveyer , then select tension station and its installation location according to specific condition. Generally speaking, for the belt conveyer of short distance, can adopt the structural stationary tension station of

54、simple, period adjustment tension; Is away from the regular belt conveyer of not large longer, tension requirement , can adopt heavy hammer type tension station,hammer type ten</p><p>　　淺談帶式輸送機(jī)的拉緊裝置</p>

55、;<p>　　帶式輸送機(jī)又稱(chēng)膠帶輸送機(jī)，現(xiàn)場(chǎng)俗稱(chēng)“皮帶”，是廠礦企業(yè)常見(jiàn)的連續(xù)運(yùn)輸設(shè)備，尤其在煤礦井下，使用尤為廣泛。帶式輸送機(jī)的主要部件包括輸送帶、驅(qū)動(dòng)裝置、托輥、滾筒、機(jī)架、張緊裝置、制動(dòng)器、輔助設(shè)備以及機(jī)電保護(hù)裝置等等。設(shè)計(jì)帶式輸送機(jī)時(shí)，首先應(yīng)確定原始的計(jì)算數(shù)據(jù)，如輸送機(jī)的計(jì)算生產(chǎn)率，輸送機(jī)的輸送線路圖，輸送機(jī)的工作制，被運(yùn)輸物料的物理機(jī)械性能以及輸送機(jī)的安裝特征和工作條件，給料和卸料方式等等；而在設(shè)計(jì)選型計(jì)算中需要

56、合理選擇相關(guān)參數(shù)，如帶寬、帶速、驅(qū)動(dòng)滾筒圍包角，部件的運(yùn)行阻力系數(shù)等，使其接近實(shí)際運(yùn)行狀態(tài)值，以提高帶式輸送機(jī)的綜合技術(shù)及經(jīng)濟(jì)效益。由于帶式輸送機(jī)是靠輸送帶與驅(qū)動(dòng)滾筒的摩擦來(lái)傳遞牽引力的，因此，在各個(gè)參數(shù)都確定的情況下，就可根據(jù)輸送帶運(yùn)行中對(duì)張力的要求來(lái)設(shè)計(jì)張緊裝置，包括張緊裝置的型式、安裝位置、張力調(diào)節(jié)范圍及特點(diǎn)等等。張緊裝置作為帶式輸送機(jī)必不可少的重要組成部分它的性能好壞直接影響帶式輸送機(jī)的性能。在帶式輸送機(jī)系統(tǒng)中，張緊裝置的主要作

57、用有以下幾點(diǎn):</p><p>　?。?）保證輸送帶在驅(qū)動(dòng)滾筒分離點(diǎn)有適當(dāng)?shù)膹埩σ苑乐馆斔蛶Т蚧?lt;/p><p>　　帶式輸送機(jī)是依靠輸送帶與驅(qū)動(dòng)滾筒間的摩擦，在相遇點(diǎn)與分離點(diǎn)產(chǎn)生一個(gè)張力差作為系統(tǒng)的牽引力。因此，為使帶式輸送機(jī)能夠穩(wěn)定運(yùn)行，需要保證輸送帶在驅(qū)動(dòng)滾筒分離點(diǎn)處有足夠的張力，以使輸送帶能夠依靠與滾筒的摩擦傳遞系統(tǒng)所需的牽引力。若分離點(diǎn)處張力過(guò)小，輸送帶傳遞的摩擦牽引力不足以使帶

58、式輸送機(jī)運(yùn)行，輸送帶就會(huì)在滾筒上打滑。</p><p>　?。?）保證輸送帶周長(zhǎng)上各點(diǎn)具有必要的張力以滿(mǎn)足懸垂度要求</p><p>　　輸送帶在兩托輥間的懸垂度不應(yīng)過(guò)大，否則輸送帶會(huì)應(yīng)過(guò)分松弛喪失槽形而導(dǎo)致物料和輸送帶跑偏，引起撒料，增加運(yùn)行阻力等。因此自動(dòng)張緊裝置應(yīng)能保證輸送帶在最小張力點(diǎn)處有足夠的張力以限制輸送帶在托輥之間的懸垂度，使帶式輸送機(jī)穩(wěn)定運(yùn)行。</p><

59、;p>　?。?）啟、制動(dòng)等非穩(wěn)定工況下動(dòng)張力的調(diào)節(jié)</p><p>　　起動(dòng)過(guò)程中，由于帶式輸送機(jī)加速運(yùn)動(dòng)，輸送帶需傳遞的牽引力要比穩(wěn)定運(yùn)行時(shí)大得多，因此須提高驅(qū)動(dòng)滾筒分離點(diǎn)張力值以產(chǎn)生更大的牽引力。而制動(dòng)過(guò)程中，尤其對(duì)長(zhǎng)距離、大運(yùn)量的輸送機(jī)，由于慣性力的作用，緊邊處輸送帶張力會(huì)減小，甚至可能引起疊帶:松邊處輸送帶張力會(huì)增大，甚至可能引起斷帶，因此須及時(shí)調(diào)整張力值。另外，運(yùn)行過(guò)程中，由于負(fù)載的變化而使得皮帶

60、出現(xiàn)突然的張力異常，張緊裝置應(yīng)給予及時(shí)調(diào)整，減少皮帶打滑、斷帶等事故。</p><p>　?。?）補(bǔ)償輸送帶的彈性伸長(zhǎng)和線粘性伸長(zhǎng)</p><p>　　時(shí)間長(zhǎng)了輸送帶會(huì)自動(dòng)伸長(zhǎng)，而且在過(guò)渡工況下發(fā)生永久伸長(zhǎng)，因此需補(bǔ)償塑性變形與過(guò)渡工況時(shí)輸送帶伸長(zhǎng)量的變化。由于負(fù)載變化會(huì)引起輸送帶發(fā)生長(zhǎng)度變化，蠕變現(xiàn)象也會(huì)造成輸送帶伸長(zhǎng)，張緊力是變化的，必須經(jīng)常調(diào)節(jié)張緊滾筒的位置，并能保證帶式輸送機(jī)的正常

61、運(yùn)行。</p><p>　?。?）為輸送帶重新接頭提供必要的行程</p><p>　　每部帶式輸送機(jī)都有若干個(gè)接頭，可能在某一時(shí)間接頭會(huì)出現(xiàn)問(wèn)題，必須截頭重做，張緊裝置為帶式輸送機(jī)已準(zhǔn)備了負(fù)荷以外的輸送帶，這樣接頭故障就可以通過(guò)放松張緊裝置重新接頭來(lái)解決問(wèn)題。對(duì)于可伸縮帶式輸送機(jī)，當(dāng)儲(chǔ)帶區(qū)儲(chǔ)滿(mǎn)帶時(shí)，即可通過(guò)張緊裝置將多余的輸送帶取出。</p><p>　　張緊裝置對(duì)

62、帶式輸送機(jī)運(yùn)輸系統(tǒng)有著不可替代的重要作用，因此，國(guó)內(nèi)外學(xué)者對(duì)其進(jìn)行了大量的研究，開(kāi)發(fā)了許多新產(chǎn)品。其發(fā)展過(guò)程大致可歸納為以下三個(gè)階段：</p><p>　　第一階段，純機(jī)械張緊階段。這一階段的主要產(chǎn)品有：螺旋張緊、固定式絞車(chē)張緊與重錘式張緊。重錘式張緊裝置通過(guò)滑輪組和重錘塊達(dá)到張緊的目的，當(dāng)膠帶伸長(zhǎng)時(shí)，能自動(dòng)吸收其伸長(zhǎng)。固定式絞車(chē)張緊的功能僅僅是張緊，當(dāng)膠帶由于種種原因伸長(zhǎng)而張緊力下降時(shí)，只能通過(guò)人的觀察發(fā)現(xiàn)后重

63、新張緊。由于帶式輸送機(jī)在起動(dòng)和正常運(yùn)行時(shí)對(duì)輸送帶張力要求是不同的，而固定式絞車(chē)張緊在輸送機(jī)運(yùn)轉(zhuǎn)過(guò)程中位置始終是固定的，為克服此缺點(diǎn)，可將其改為半固定式張緊，即起動(dòng)時(shí)，張緊滾筒固定在起動(dòng)位置上，正常運(yùn)行時(shí)，固定在運(yùn)行位置上，兩個(gè)位置用行程開(kāi)關(guān)控制，國(guó)內(nèi)也有生產(chǎn)此種張緊裝置的。</p><p>　　第二階段，張緊力可調(diào)階段。這個(gè)階段的典型產(chǎn)品是自動(dòng)絞車(chē)(機(jī)械絞車(chē)或液壓絞車(chē))張緊裝置。其技術(shù)發(fā)展表現(xiàn)為只能實(shí)現(xiàn)在穩(wěn)定(勻

64、速)階段的自動(dòng)張緊，保持膠帶在該階段的張力恒定，而在起動(dòng)與制動(dòng)等不穩(wěn)定運(yùn)行工況下則與固定式絞車(chē)相同。其結(jié)構(gòu)特征表現(xiàn)為帶有閘，絞車(chē)張緊時(shí)松閘，停止時(shí)緊閘。絞車(chē)運(yùn)轉(zhuǎn)的時(shí)間很短，而大部分時(shí)間處于停車(chē)待命狀態(tài)。壓縮空氣驅(qū)動(dòng)的液壓張緊系統(tǒng)是利用壓縮空器驅(qū)動(dòng)油泵，給張緊油缸提供壓力油來(lái)張緊輸送帶。該張緊系統(tǒng)僅在德國(guó)、英國(guó)等國(guó)得到應(yīng)用，其結(jié)構(gòu)緊湊、工作可靠，占地面積小。</p><p>　　第三階段，動(dòng)態(tài)自動(dòng)張緊階段。主要產(chǎn)品

65、有液壓絞車(chē)自動(dòng)張緊與液壓缸自動(dòng)張緊，如國(guó)內(nèi)外使用較多的KJ2029型礦用帶式輸送機(jī)自動(dòng)張緊系統(tǒng)，法國(guó)A型帶式輸送機(jī)液壓缸自動(dòng)張緊系統(tǒng)、DYI.液壓缸型張緊系統(tǒng)，這幾種自動(dòng)張緊系統(tǒng)都可以做到自動(dòng)調(diào)節(jié)輸送帶張緊力，動(dòng)態(tài)響應(yīng)快，能在起動(dòng)階段和正常運(yùn)行階段兩種工況下提供相應(yīng)的張緊力。液壓絞車(chē)長(zhǎng)時(shí)間處于工作狀杰，其結(jié)構(gòu)特征是不帶閘。自動(dòng)張緊裝置采用大拉力張緊裝置張緊輸送帶，不但能根據(jù)主動(dòng)滾筒的牽引力來(lái)自動(dòng)調(diào)節(jié)張緊力，而且還能補(bǔ)償輸送帶的彈性伸長(zhǎng)和

66、塑性變形，同時(shí)配備張力傳感器及變送器，測(cè)定輸送帶的張力。當(dāng)輸送帶張力發(fā)生變化，超過(guò)輸送機(jī)正常運(yùn)行的范圍時(shí)，自動(dòng)張緊裝置迅速動(dòng)作，調(diào)整輸送帶張力，保證輸送機(jī)的正常運(yùn)行。自動(dòng)張緊裝置與自移機(jī)尾配合使用，可在輸送機(jī)不停機(jī)的條件下，實(shí)現(xiàn)輸送機(jī)機(jī)尾的移動(dòng)和輸送帶的伸縮，大大提高了帶式輸送機(jī)的工作效率。</p><p>　　目前，國(guó)內(nèi)外對(duì)各種張緊裝置的適用性，即張緊裝置在不同運(yùn)量、運(yùn)輸距離、運(yùn)輸傾角、運(yùn)行工況下的合理適用范圍

67、尚無(wú)較統(tǒng)一的看法，這說(shuō)明己有的定性結(jié)論還不完善，必須要有定量地結(jié)論來(lái)指導(dǎo)設(shè)計(jì)。從實(shí)際的使用情況看，絞車(chē)張緊和液壓張緊可以實(shí)現(xiàn)自動(dòng)控制且張緊力可調(diào)，重錘張緊裝置有較高的安全可靠性。隨著工業(yè)和技術(shù)的發(fā)展，具有長(zhǎng)距離、大運(yùn)量、高帶速特征的大型帶式輸送機(jī)已成為發(fā)展的主流，由此對(duì)張緊裝置提出更高要求，傳統(tǒng)的張緊裝置逐漸顯示出其缺點(diǎn)，技術(shù)人員已將對(duì)張緊系統(tǒng)的研究方向逐步轉(zhuǎn)入到自動(dòng)張緊領(lǐng)域，如中國(guó)礦業(yè)大學(xué)開(kāi)發(fā)的YZL系列皮帶機(jī)液壓絞車(chē)式自動(dòng)張緊裝置，

68、它能根據(jù)帶式輸送機(jī)起動(dòng)加速階段和平穩(wěn)運(yùn)行階段對(duì)皮帶張力的不同要求，提供相應(yīng)的皮帶張力，并能在皮帶張力發(fā)生變化時(shí)準(zhǔn)確監(jiān)測(cè)并及時(shí)自動(dòng)調(diào)整。自動(dòng)張緊裝置可大大提高帶式輸送機(jī)運(yùn)行的可靠性。早在上世紀(jì)40年代，自動(dòng)張緊系統(tǒng)就已在國(guó)外問(wèn)世，蘇聯(lián)和日本在此領(lǐng)域起步較早，而國(guó)內(nèi)使用自動(dòng)張緊系統(tǒng)的歷史并不太長(zhǎng)，張緊系統(tǒng)的理論研究和設(shè)計(jì)方法還不完善，與國(guó)外相比具有張緊力響應(yīng)慢、布局不合理、存在振動(dòng)現(xiàn)象等不足之處，而且對(duì)自動(dòng)張緊系統(tǒng)的選型計(jì)算方法也很模糊，沒(méi)

69、有充分的理論基礎(chǔ)。</p><p>　　對(duì)于傾角不大的帶式輸送機(jī)，大多采用車(chē)式張緊，其中包括張緊小車(chē)、張緊滾筒、張力生成設(shè)備及其控制系統(tǒng)，張力生成設(shè)備包括重錘、絞車(chē)、液壓油缸等等。</p><p>　　張緊裝置調(diào)節(jié)皮帶張力的方式可以是保持恒定的皮帶張力值；或保持兩種恒定的皮帶張力值(起動(dòng)張力值和運(yùn)行張力值)；或保持恒定的張力比。在帶式輸送機(jī)系統(tǒng)的布置中，合理的確定張緊裝置，是保證輸送機(jī)正常

70、運(yùn)轉(zhuǎn)、起動(dòng)和制動(dòng)時(shí)安全可靠以及經(jīng)濟(jì)合理的必要前提，張緊裝置的工作特性不僅取決于其本身的結(jié)構(gòu)性能，而且還與帶式輸送機(jī)的起、制動(dòng)特性，張緊裝置的安裝位置有關(guān)。因而，要精確的分析張緊裝置的工作特性必須同帶式輸送機(jī)整機(jī)結(jié)合起來(lái)，不能孤立地分析張緊裝置。但是在帶式輸送機(jī)結(jié)構(gòu)、起制動(dòng)方式及張緊裝置安裝位置確定的情況下，張緊裝置的特性就取決于其自身性能。</p><p>　　張緊裝置按結(jié)構(gòu)型式可分固定式、重錘式和自動(dòng)式三種。&

71、lt;/p><p>　　（1）固定式張緊包括螺旋張緊和固定絞車(chē)張緊。螺旋張緊系統(tǒng)中，張緊滾筒的軸承安裝在活動(dòng)架上，活動(dòng)架可在導(dǎo)軌上滑動(dòng)，當(dāng)旋轉(zhuǎn)螺桿時(shí)使活動(dòng)架上的螺母跟活動(dòng)架一起前進(jìn)和后退，達(dá)到張緊和放松的目的。其特點(diǎn)是結(jié)構(gòu)簡(jiǎn)單，但張緊行程太小，只適用于短距離的輸送機(jī)，一般機(jī)長(zhǎng)小于80米時(shí)才選用。</p><p>　　螺旋張緊的缺點(diǎn)是：輸送帶經(jīng)過(guò)一段時(shí)間使用后，由于塑性變形而伸長(zhǎng)，如不及時(shí)調(diào)整，

72、輸送帶張緊力會(huì)減小，輸送帶會(huì)變松而引起輸送帶打滑。另外，由于負(fù)載經(jīng)常發(fā)生變化，輸送帶受負(fù)載沖擊，致使張緊滾筒的固定螺栓松動(dòng)，螺桿后退，由此造成輸送帶松馳而導(dǎo)致輸送帶打滑。還有螺桿生銹后，導(dǎo)致輸送帶伸長(zhǎng)后不能用擰緊螺桿的方法來(lái)張緊。</p><p>　　固定絞車(chē)張緊是利用小型絞車(chē)來(lái)張緊。絞車(chē)一般用蝸輪蝸桿減速器帶動(dòng)卷筒來(lái)纏繞鋼絲繩，從而張緊輸送帶。這種張緊系統(tǒng)的優(yōu)點(diǎn)是體積小拉力大，所以被廣泛應(yīng)用于煤礦井下帶式輸送機(jī)

73、中。缺點(diǎn)是它只能根據(jù)需要調(diào)節(jié)，調(diào)節(jié)好后產(chǎn)生固定的張緊力。當(dāng)絞車(chē)和控制系統(tǒng)出現(xiàn)問(wèn)題時(shí)，對(duì)帶式輸送機(jī)不能產(chǎn)生恒定的張緊力或張緊力失效，安全可靠性相對(duì)降低。</p><p>　　固定絞車(chē)張緊方式只能定期調(diào)整輸送帶的張緊程度，一般開(kāi)始處于過(guò)張緊狀態(tài)，使帶式輸送機(jī)的輸送帶承受額外的附加載荷，而在運(yùn)行過(guò)程中張緊力隨著輸送帶永久變形增加而逐漸減小，經(jīng)常出現(xiàn)打滑現(xiàn)象。另外，用固定絞車(chē)作為長(zhǎng)距離帶式輸送機(jī)的張緊裝置，輸送帶的動(dòng)應(yīng)力

74、大，對(duì)一定強(qiáng)度的輸送帶，其安全可靠性將下降，容易出現(xiàn)斷帶事故。一旦斷帶事故發(fā)生，需要重新連接輸送帶，清理落煤，通常需停產(chǎn)24小時(shí)甚至更長(zhǎng)的時(shí)間。此外，斷帶事故的發(fā)生，還會(huì)造成輸送機(jī)旁邊行人的傷亡事故。</p><p>　?。?）重錘式張緊包括單重錘式，多重錘式及重錘車(chē)式。重錘式張緊裝置結(jié)構(gòu)簡(jiǎn)單，應(yīng)用較廣泛，能保證張緊力在各種運(yùn)行工況下保持恒定不變，并且能自動(dòng)吸收和補(bǔ)償輸送帶的伸長(zhǎng)。重錘式張緊是重錘通過(guò)鋼絲繩作用于

75、張緊滾筒從而張緊輸送帶。重錘車(chē)式張緊是重錘通過(guò)鋼絲繩拉動(dòng)張緊小車(chē)從而張緊輸送帶，張緊小車(chē)可以水平或傾斜布置，也可以垂直布置。重錘式張緊是利用重錘自重來(lái)張緊的，為了懸掛重錘需開(kāi)一個(gè)專(zhuān)門(mén)的峒室。在張緊小車(chē)布置于傾斜坡度上的帶式輸送機(jī)系統(tǒng)中，也可以不設(shè)重錘而將重物放在張緊小車(chē)上，利用坡度使裝有重物的張緊小車(chē)產(chǎn)生下滑力從而張緊輸送帶，也稱(chēng)為重錘車(chē)式張緊。重錘式張緊裝置的特點(diǎn)是張緊力不變，安全可靠性較高；張緊力不變同時(shí)也是其缺點(diǎn)，由于張緊力不能調(diào)

76、節(jié)，在輸送機(jī)起動(dòng)階段以及輸送量發(fā)生變化時(shí)輸送帶會(huì)因張力不足而打滑在起動(dòng)和非穩(wěn)定運(yùn)行過(guò)程中因張力不合適也容易產(chǎn)生振動(dòng)。另外，受布置空間的限制，重錘位移量不能過(guò)大。</p><p>　?。?）自動(dòng)式張緊裝置是近代輸送機(jī)中廣泛應(yīng)用的張緊裝置型式，它可使輸送帶具有合理的張力分布，并自動(dòng)補(bǔ)償輸送帶的彈性變形和塑性伸長(zhǎng)。自動(dòng)張緊裝置一般由絞車(chē)?yán)p繞鋼絲繩來(lái)拉緊滾筒從而張緊皮帶。</p><p>　　自動(dòng)

77、絞車(chē)張緊裝置按驅(qū)動(dòng)形式的不同，可分為電動(dòng)絞車(chē)張緊裝置和液壓絞車(chē)張緊裝置；按被調(diào)節(jié)分離點(diǎn)張力的變化規(guī)律，又可分為穩(wěn)定式、隨動(dòng)式和綜合式三種型式。穩(wěn)定式自動(dòng)張緊裝置能使分離點(diǎn)輸送帶張力在一定誤差范圍內(nèi)保持恒定，而不依賴(lài)帶式輸送機(jī)負(fù)荷的變化和粘著條件以及其它參數(shù)。為保證帶式輸送機(jī)起動(dòng)時(shí)輸送帶不打滑，要求穩(wěn)定式自動(dòng)張緊裝置能保證輸送機(jī)起動(dòng)時(shí)輸送帶分離點(diǎn)張力達(dá)到穩(wěn)定運(yùn)行值得1.4～1.8倍。隨動(dòng)式自動(dòng)張緊裝置能使輸送帶相遇點(diǎn)張力和分離點(diǎn)張力之比值

78、保持為定值，綜合式自動(dòng)張緊裝置的特點(diǎn)是帶式輸送機(jī)起動(dòng)時(shí)，它的作用方式是隨動(dòng)式的，而在穩(wěn)定運(yùn)行時(shí)，它的作用方式是穩(wěn)定式的:或者相反。</p><p>　　自動(dòng)絞車(chē)張緊裝置的優(yōu)點(diǎn)逐漸被人們廣泛認(rèn)識(shí)，但也存在許多不足。電動(dòng)絞車(chē)張緊裝置是用張力傳感器作為反饋，根據(jù)帶式輸送機(jī)的不同運(yùn)行工況自動(dòng)調(diào)整張緊力的大小，受張力傳感器質(zhì)量不高或機(jī)械系統(tǒng)慣性及信號(hào)滯后等影響，自動(dòng)絞車(chē)有誤動(dòng)作現(xiàn)象，影響其使用效果；液壓絞車(chē)張緊裝置是由液壓

79、站產(chǎn)生的壓力油通過(guò)控制液壓絞車(chē)來(lái)調(diào)節(jié)張緊力的大小，由于液壓站和油缸始終處于工作狀態(tài)，當(dāng)液壓系統(tǒng)或控制系統(tǒng)出現(xiàn)故障時(shí)，對(duì)輸送帶不能產(chǎn)生張緊力或張緊力失效，安全可靠性相對(duì)降低。除絞車(chē)外，也可采用液壓缸作為張緊執(zhí)行元件，液壓缸自動(dòng)張緊裝置也可以做到自動(dòng)調(diào)節(jié)輸送帶張緊力，滿(mǎn)足輸送帶在起動(dòng)以及穩(wěn)定運(yùn)行工況所需張緊力不同的要求，但同樣存在許多局限，受張緊油缸行程的限制，整個(gè)張緊系統(tǒng)不能有較大的張緊行程，所以液壓缸自動(dòng)張緊裝置調(diào)整范圍小，只適用于短距

80、離的帶式輸送機(jī):另外，液壓缸長(zhǎng)期處于高壓狀態(tài)會(huì)導(dǎo)致密封件及液壓件損壞，導(dǎo)致系統(tǒng)泄漏，從而造成輸送帶張緊力急劇下降，引發(fā)打滑、磨損等事故。</p><p>　　在實(shí)際應(yīng)用中，首先要根據(jù)帶式輸送機(jī)的工作狀況合理計(jì)算牽引力，然后根據(jù)具體情況來(lái)選擇張緊裝置及其安裝位置。一般來(lái)說(shuō)，對(duì)于短距離的帶式輸送機(jī)，可采用結(jié)構(gòu)簡(jiǎn)單，周期調(diào)整張力的固定式張緊裝置；距離較長(zhǎng)，張力要求不大的固定帶式輸送機(jī)，可采用重錘式張緊裝置，重錘式張緊裝