DTII（A）型帶式輸送機(jī)【說明書+CAD圖紙】

資源目錄里展示的全都有，所見即所得。下載后全都有,請放心下載。原稿可自行編輯修改=【QQ：401339828 或11970985 有疑問可加】 DTII（A）型帶式輸送機(jī)摘要本次畢業(yè)設(shè)計(jì)是關(guān)于礦用固定式帶式輸送機(jī)的設(shè)計(jì)。首先對膠帶輸送機(jī)作了簡單的概述；接著分析了帶式輸送機(jī)的選型原則及計(jì)算方法；然后根據(jù)這些設(shè)計(jì)準(zhǔn)則與計(jì)算選型方法按照給定參數(shù)要求進(jìn)行選型設(shè)計(jì)；接著對所選擇的輸送機(jī)各主要零部件進(jìn)行了校核。普通型帶式輸送機(jī)由六個主要部件組成：傳動裝置，機(jī)尾和導(dǎo)回裝置，中部機(jī)架，拉緊裝置以及膠帶。最后簡單的說明了輸送機(jī)的安裝與維護(hù)。目前，膠帶輸送機(jī)正朝著長距離，高速度，低摩擦的方向發(fā)展，近年來出現(xiàn)的氣墊式膠帶輸送機(jī)就是其中的一個。在膠帶輸送機(jī)的設(shè)計(jì)、制造以及應(yīng)用方面,目前我國與國外先進(jìn)水平相比仍有較大差距,國內(nèi)在設(shè)計(jì)制造帶式輸送機(jī)過程中存在著很多不足。本次帶式輸送機(jī)設(shè)計(jì)代表了設(shè)計(jì)的一般過程, 對今后的選型設(shè)計(jì)工作有一定的參考價值。 關(guān)鍵詞：帶式輸送機(jī)；選型設(shè)計(jì)；主要部件AbstractThe design is a graduation project about the belt conveyor used in coal mine. At first, it is introduction about the belt conveyor. Next, it is the principles about choose component parts of belt conveyor. After that the belt conveyor abase on the principle is designed. Then, it is checking computations about main component parts. The ordinary belt conveyor consists of six main parts: Drive Unit, Jib or Delivery End, Tail Ender Return End, Intermediate Structure, Loop Take-Up and Belt. At last, it is explanation about fix and safeguard of the belt conveyor. Today, long distance, high speed, low friction is the direction of belt conveyors development. Air cushion belt conveyor is one of them. At present, we still fall far short of abroad advanced technology in design, manufacture and using. There are a lot of wastes in the design of belt conveyor. Keyword: belt conveyor; Lectotype Design;main parts目 錄1緒論12帶式輸送機(jī)概述22.1 帶式輸送機(jī)的應(yīng)用22.2 帶式輸送機(jī)的分類22.3 各種帶式輸送機(jī)的特點(diǎn)32.4 帶式輸送機(jī)的發(fā)展?fàn)顩r42.5 帶式輸送機(jī)的工作原理52.6 帶式輸送機(jī)的結(jié)構(gòu)和布置形式72.6.1 帶式輸送機(jī)的結(jié)構(gòu)72.6.2 布置方式83 帶式輸送機(jī)的設(shè)計(jì)計(jì)算103.1 已知原始數(shù)據(jù)及工作條件103.2 計(jì)算步驟113.2.1 帶寬的確定113.2.2 輸送帶寬度的核算143.3 圓周驅(qū)動力143.3.1 計(jì)算公式143.3.2 主要阻力計(jì)算163.3.3 主要特種阻力計(jì)算183.3.4 附加特種阻力計(jì)算193.3.5 傾斜阻力計(jì)算203.4 輸送帶張力計(jì)算213.4.1 輸送帶不打滑條件校核213.4.2 輸送帶下垂度校核223.4.3 各特性點(diǎn)張力計(jì)算233.5 輸送帶的強(qiáng)度驗(yàn)算263.6 傳動滾筒、改向滾筒合張力計(jì)算283.6.1 改向滾筒合張力計(jì)算283.6.2 傳動滾筒合張力計(jì)算293.6.3 傳動滾筒最大扭矩計(jì)算293.7 拉緊裝置的設(shè)計(jì)計(jì)算294 驅(qū)動裝置的選用與設(shè)計(jì)314.1 電機(jī)的選用314.1.1 電動機(jī)功率計(jì)算314.2 減速器的選用334.2.1 傳動裝置的總傳動比334.3 液力偶合器344.4 聯(lián)軸器355 帶式輸送機(jī)部件的選用385.1 輸送帶385.1.1 輸送帶的分類385.1.2 輸送帶的連接405.2 傳動滾筒415.2.1 傳動滾筒的作用及類型415.2.2 傳動滾筒的選型及設(shè)計(jì)425.2.3 傳動滾筒的選型435.2.4傳動滾筒軸的設(shè)計(jì)445.3 托輥455.3.1 托輥的作用與類型455.3.2 托輥的選型495.3.3 托輥的校核535.4 制動裝置555.4.1 制動裝置的作用555.4.2 制動裝置的種類555.4.3 制動裝置的選型585.5 改向裝置585.6 拉緊裝置595.6.1 拉緊裝置的作用595.6.2 張緊裝置在使用中應(yīng)滿足的要求595.6.3 拉緊裝置布置時應(yīng)遵循的原則605.6.4 拉緊裝置的種類及特點(diǎn)606其他部件的選用636.1 機(jī)架與中間架636.1.1 機(jī)架式支承滾筒及承受輸送帶張力的裝置636.2 給料裝置646.2.1 對給料裝置的基本要求646.2.2 裝料段攔板的布置及尺寸656.3 卸料裝置666.4 清掃裝置666.5 頭部漏斗676.6 電氣及安全保護(hù)裝置67總結(jié)69致 謝71參考文獻(xiàn)72 本科畢業(yè)設(shè)計(jì)（論文）說明書1緒論帶式輸送機(jī)是連續(xù)運(yùn)行的運(yùn)輸設(shè)備，在冶金、采礦、動力、建材等重工業(yè)部門及交通運(yùn)輸部門中主要用來運(yùn)送大量散狀貨物，如礦石、煤、砂等粉、塊狀物和包裝好成件物品。帶式輸送機(jī)是煤礦最理想的高效連續(xù)運(yùn)輸設(shè)備，與其他運(yùn)輸設(shè)備相比，不僅具有長距離、大運(yùn)量、連續(xù)輸送等優(yōu)點(diǎn)，而且運(yùn)行可靠,易于實(shí)現(xiàn)自動化、集中化控制,特別是對高產(chǎn)高效礦井，帶式輸送機(jī)已成為煤炭高效開采機(jī)電一體化技術(shù)與裝備的關(guān)鍵設(shè)備。特別是近10年，長距離、大運(yùn)量、高速度的帶式輸送機(jī)的出現(xiàn)，使其在礦山建設(shè)的井下巷道、礦井地表運(yùn)輸系統(tǒng)及露天采礦場、選礦廠中的應(yīng)用又得到進(jìn)一步推廣。選擇帶式輸送機(jī)這種通用機(jī)械的設(shè)計(jì)作為畢業(yè)設(shè)計(jì)的選題，能培養(yǎng)我們獨(dú)立解決工程實(shí)際問題的能力，通過這次畢業(yè)設(shè)計(jì)是對所學(xué)基本理論和專業(yè)知識的一次綜合運(yùn)用，也使我們的設(shè)計(jì)、計(jì)算和繪圖能力都得到了全面的訓(xùn)練。原始參數(shù)：1）輸送物料：煤2）物料特性：（1）塊度：0300mm（2）散裝密度：0.90t/m3（3）在輸送帶上堆積角：=20（4）物料溫度：503）工作環(huán)境：井下4）輸送系統(tǒng)及相關(guān)尺寸：（1）運(yùn)距：300m （2）傾斜角：=0（3）最大運(yùn)量:350t2帶式輸送機(jī)概述2.1 帶式輸送機(jī)的應(yīng)用帶式輸送機(jī)是連續(xù)運(yùn)輸機(jī)的一種，連續(xù)運(yùn)輸機(jī)是固定式或運(yùn)移式起重運(yùn)輸機(jī)中主要類型之一，其運(yùn)輸特點(diǎn)是形成裝載點(diǎn)到裝載點(diǎn)之間的連續(xù)物料流，靠連續(xù)物料流的整體運(yùn)動來完成物流從裝載點(diǎn)到卸載點(diǎn)的輸送。在工業(yè)、農(nóng)業(yè)、交通等各企業(yè)中，連續(xù)運(yùn)輸機(jī)是生產(chǎn)過程中組成有節(jié)奏的流水作業(yè)運(yùn)輸線不可缺少的組成部分。連續(xù)運(yùn)輸機(jī)可分為：（1）具有撓性牽引物件的輸送機(jī)，如帶式輸送機(jī)，板式輸送機(jī)，刮板輸送機(jī)，斗式輸送機(jī)、自動扶梯及架空索道等；（2）不具有撓性牽引物件的輸送機(jī)，如螺旋輸送機(jī)、振動輸送機(jī)等；（3）管道輸送機(jī)(流體輸送)，如氣力輸送裝置和液力輸送管道。其中帶輸送機(jī)是連續(xù)運(yùn)輸機(jī)中是使用最廣泛的，帶式輸送機(jī)運(yùn)行可靠，輸送量大，輸送距離長，維護(hù)簡便，適應(yīng)于冶金煤炭，機(jī)械電力，輕工，建材，糧食等各個部門。 2.2 帶式輸送機(jī)的分類帶式輸送機(jī)分類方法有多種，按運(yùn)輸物料的輸送帶結(jié)構(gòu)可分成兩類，一類是普通型帶式輸送機(jī)，這類帶式輸送機(jī)在輸送帶運(yùn)輸物料的過程中，上帶呈槽形，下帶呈平形，輸送帶有托輥托起，輸送帶外表幾何形狀均為平面；另外一類是特種結(jié)構(gòu)的帶式輸送機(jī)，各有各的輸送特點(diǎn)。其簡介如下：2.3 各種帶式輸送機(jī)的特點(diǎn)（1）QD80輕型固定式帶輸送機(jī) QD80輕型固定式帶輸送機(jī)與TD型相比，其帶較薄、載荷也較輕，運(yùn)距一般不超過100m，電機(jī)容量不超過22kw。（2） 它屬于高強(qiáng)度帶式輸送機(jī)，其輸送帶的帶芯中有平行的細(xì)鋼繩，一臺運(yùn)輸機(jī)運(yùn)距可達(dá)幾公里到幾十公里。（3）U形帶式輸送機(jī) 它又稱為槽形帶式輸送機(jī)，其明顯特點(diǎn)是將普通帶式輸送機(jī)的槽形托輥角由提高到使輸送帶成U形。這樣一來輸送帶與物料間產(chǎn)生擠壓，導(dǎo)致物料對膠帶的摩擦力增大，從而輸送機(jī)的運(yùn)輸傾角可達(dá)25。（4）管形帶式輸送機(jī) U形帶式輸送帶進(jìn)一步的成槽，最后形成一個圓管狀，即為管形帶式輸送機(jī)，因?yàn)檩斔蛶П痪沓梢粋€圓管，故可以實(shí)現(xiàn)閉密輸送物料，可明顯減輕粉狀物料對環(huán)境的污染，并且可以實(shí)現(xiàn)彎曲運(yùn)行。（5）氣墊式帶輸送機(jī) 其輸送帶不是運(yùn)行在托輥上的，而是在空氣膜(氣墊)上運(yùn)行，省去了托輥，用不動的帶有氣孔的氣室盤形槽和氣室取代了運(yùn)行的托輥，運(yùn)動部件的減少，總的等效質(zhì)量減少，阻力減小，效率提高，并且運(yùn)行平穩(wěn)，可提高帶速。但一般其運(yùn)送物料的塊度不超過300mm。增大物流斷面的方法除了用托輥把輸送帶強(qiáng)壓成槽形外，也可以改變輸送帶本身，把輸送帶的運(yùn)載面做成垂直邊的，并且?guī)в袡M隔板。一般把垂直側(cè)擋邊作成波狀，故稱為波狀帶式輸送機(jī)，這種機(jī)型適用于大傾角，傾角在30以上，最大可達(dá)90。（6）壓帶式帶輸送機(jī) 它是用一條輔助帶對物料施加壓力。這種輸送機(jī)的主要優(yōu)點(diǎn)是：輸送物料的最大傾角可達(dá)90，運(yùn)行速度可達(dá)6m/s，輸送能力不隨傾角的變化而變化，可實(shí)現(xiàn)松散物料和有毒物料的密閉輸送。其主要缺點(diǎn)是結(jié)構(gòu)復(fù)雜、輸送帶的磨損增大和能耗較大。（7）鋼繩牽引帶式輸送機(jī) 它是無際繩運(yùn)輸與帶式運(yùn)輸相結(jié)合的產(chǎn)物，既具有鋼繩的高強(qiáng)度、牽引靈活的特點(diǎn)，又具有帶式運(yùn)輸?shù)倪B續(xù)、柔性的優(yōu)點(diǎn)。2.4 帶式輸送機(jī)的發(fā)展?fàn)顩r目前帶式輸送機(jī)已廣泛應(yīng)用于國民經(jīng)經(jīng)濟(jì)各個部門，近年來在露天礦和地下礦的聯(lián)合運(yùn)輸系統(tǒng)中帶式輸送機(jī)又成為重要的組成部分。主要有：鋼繩芯帶式輸送機(jī)、鋼繩牽引膠帶輸送機(jī)和排棄場的連續(xù)輸送設(shè)施等。這些輸送機(jī)的特點(diǎn)是輸送能力大(可達(dá)30000t/h)，適用范圍廣(可運(yùn)送礦石，煤炭，巖石和各種粉狀物料，特定條件下也可以運(yùn)人)，安全可靠，自動化程度高，設(shè)備維護(hù)檢修容易，爬坡能力大(可達(dá)16)，經(jīng)營費(fèi)用低，由于縮短運(yùn)輸距離可節(jié)省基建投資。目前，帶式輸送機(jī)的發(fā)展趨勢是：大運(yùn)輸能力、大帶寬、大傾角、增加單機(jī)長度和水平轉(zhuǎn)彎，合理使用膠帶張力，降低物料輸送能耗，清理膠帶的最佳方法等。我國已于1978年完成了鋼繩芯帶式輸送機(jī)的定型設(shè)計(jì)。鋼繩芯帶式輸送機(jī)的適用范圍：（1）適用于環(huán)境溫度一般為C；在寒冷地區(qū)驅(qū)動站應(yīng)有采暖設(shè)施；（2）可做水平運(yùn)輸，傾斜向上(16)和向下()運(yùn)輸，也可以轉(zhuǎn)彎運(yùn)輸；運(yùn)輸距離長，單機(jī)輸送可達(dá)15km；（3）可露天鋪設(shè)，運(yùn)輸線可設(shè)防護(hù)罩或設(shè)通廊；（4）輸送帶伸長率為普通帶的1/5左右；其使用壽命比普通膠帶長；其成槽性好；運(yùn)輸距離大。2.5 帶式輸送機(jī)的工作原理帶式輸送機(jī)又稱膠帶運(yùn)輸機(jī)，其主要部件是輸送帶，亦稱為膠帶，輸送帶兼作牽引機(jī)構(gòu)和承載機(jī)構(gòu)。帶式輸送機(jī)組成及工作原理如圖2-1所示，它主要包括一下幾個部分：輸送帶(通常稱為膠帶)、托輥及中間架、滾筒拉緊裝置、制動裝置、清掃裝置和卸料裝置等。1-頭部漏斗 ；2-機(jī)架；3-頭部掃清器；4-傳動滾筒 5-安全保護(hù)裝置；6-輸送帶；7-承載托輥；8-緩沖托輥；9-導(dǎo)料槽；10-改向滾筒；11-拉緊裝置 12-尾架；13-空段掃清器；14-回程托輥；15-中間架；16-電動機(jī)；17-液力偶合器；18-制動器；19-減速器；20-聯(lián)軸器圖2-1 皮帶運(yùn)輸機(jī)組成示意圖 輸送帶繞經(jīng)傳動滾筒和機(jī)尾換向滾筒形成一個無極的環(huán)形帶。輸送帶的上、下兩部分都支承在托輥上。拉緊裝置給輸送帶以正常運(yùn)轉(zhuǎn)所需要的拉緊力。工作時，傳動滾筒通過它和輸送帶之間的摩擦力帶動輸送帶運(yùn)行。物料從裝載點(diǎn)裝到輸送帶上，形成連續(xù)運(yùn)動的物流，在卸載點(diǎn)卸載。一般物料是裝載到上帶(承載段)的上面，在機(jī)頭滾筒(在此，即是傳動滾筒)卸載，利用專門的卸載裝置也可在中間卸載。普通型帶式輸送機(jī)的機(jī)身的上帶是用槽形托輥支撐，以增加物流斷面積，下帶為返回段(不承載的空帶)一般下托輥為平托輥。帶式輸送機(jī)可用于水平、傾斜和垂直運(yùn)輸。對于普通型帶式輸送機(jī)傾斜向上運(yùn)輸，其傾斜角不超過18，向下運(yùn)輸不超過15。輸送帶是帶式輸送機(jī)部件中最昂貴和最易磨損的部件。當(dāng)輸送磨損性強(qiáng)的物料時，如鐵礦石等，輸送帶的耐久性要顯著降低。提高傳動裝置的牽引力可以從以下三個方面考慮：（1）增大拉緊力。增加初張力可使輸送帶在傳動滾筒分離點(diǎn)的張力增加，此法提高牽引力雖然是可行的。但因增大必須相應(yīng)地增大輸送帶斷面，這樣導(dǎo)致傳動裝置的結(jié)構(gòu)尺寸加大，是不經(jīng)濟(jì)的。故設(shè)計(jì)時不宜采用。但在運(yùn)轉(zhuǎn)中由于運(yùn)輸帶伸長，張力減小，造成牽引力下降，可以利用拉緊裝置適當(dāng)?shù)卦龃蟪鯊埩Γ瑥亩龃?，以提高牽引力。?）增加圍包角對需要牽引力較大的場合，可采用雙滾筒傳動，以增大圍包角。（3）增大摩擦系數(shù)其具體措施可在傳動滾筒上覆蓋摩擦系數(shù)較大的襯墊，以增大摩擦系數(shù)。通過對上述傳動原理的闡述可以看出，增大圍包角是增大牽引力的有效方法。故在傳動中擬采用這種方法。2.6 帶式輸送機(jī)的結(jié)構(gòu)和布置形式 2.6.1 帶式輸送機(jī)的結(jié)構(gòu)帶式輸送機(jī)主要由以下部件組成：頭架、驅(qū)動裝置、傳動滾筒、尾架、托輥、中間架、尾部改向裝置、卸載裝置、清掃裝置、安全保護(hù)裝置等。輸送帶是帶式輸送機(jī)的承載構(gòu)件，帶上的物料隨輸送帶一起運(yùn)行，物料根據(jù)需要可以在輸送機(jī)的端部和中間部位卸下。輸送帶用旋轉(zhuǎn)的托棍支撐，運(yùn)行阻力小。帶式輸送機(jī)可沿水平或傾斜線路布置。使用光面輸送帶沿傾斜線路布置時，不同物料的最大運(yùn)輸傾角是不同的，如下表2-1所示：表2-1 不同物料的最大運(yùn)角物料種類角度物料種類角度煤塊18篩分后的石灰石12煤塊20干沙15篩分后的焦碳17未篩分的石塊180350mm礦石16水泥200200mm油田頁巖22干松泥土20由于帶式輸送機(jī)的結(jié)構(gòu)特點(diǎn)決定了其具有優(yōu)良性能，主要表現(xiàn)在：運(yùn)輸能力大，且工作阻力小，耗電量低，約為刮板輸送機(jī)的1/3到1/5；由于物料同輸送機(jī)一起移動，同刮板輸送機(jī)比較，物料破碎率??；帶式輸送機(jī)的單機(jī)運(yùn)距可以很長，與刮板輸送機(jī)比較，在同樣運(yùn)輸能力及運(yùn)距條件下，其所需設(shè)備臺數(shù)少，轉(zhuǎn)載環(huán)節(jié)少，節(jié)省設(shè)備和人員，并且維護(hù)比較簡單。由于輸送帶成本高且易損壞，故與其它設(shè)備比較，初期投資高且不適應(yīng)輸送有尖棱的物料。輸送機(jī)年工作時間一般取4500-5500小時。當(dāng)二班工作和輸送剝離物，且輸送環(huán)節(jié)較多，宜取下限；當(dāng)三班工作和輸送環(huán)節(jié)少的礦石輸送，并有儲倉時，取上限為宜。 2.6.2 布置方式電動機(jī)通過聯(lián)軸器、減速器帶動傳動滾筒轉(zhuǎn)動或其他驅(qū)動機(jī)構(gòu)，借助于滾筒或其他驅(qū)動機(jī)構(gòu)與輸送帶之間的摩擦力，使輸送帶運(yùn)動。帶式輸送機(jī)的驅(qū)動方式按驅(qū)動裝置可分為單點(diǎn)驅(qū)動方式和多點(diǎn)驅(qū)動方式兩種。通用固定式輸送帶輸送機(jī)多采用單點(diǎn)驅(qū)動方式，即驅(qū)動裝置集中的安裝在輸送機(jī)長度的某一個位置處，一般放在機(jī)頭處。單點(diǎn)驅(qū)動方式按傳動滾筒的數(shù)目分，可分為單滾筒和雙滾筒驅(qū)動。對每個滾筒的驅(qū)動又可分為單電動機(jī)驅(qū)動和多電動機(jī)驅(qū)動。因單點(diǎn)驅(qū)動方式最常用，凡是沒有指明是多點(diǎn)驅(qū)動方式的，即為單驅(qū)動方式，故一般對單點(diǎn)驅(qū)動方式，“單點(diǎn)”兩字省略。單筒、單電動機(jī)驅(qū)動方式最簡單，在考慮驅(qū)動方式時應(yīng)是首選方式。在大運(yùn)量、長距離的鋼繩芯膠帶輸送機(jī)中往往采用多電動機(jī)驅(qū)動。帶式輸送機(jī)常見典型的布置方式如圖2-2所示：圖2-2 帶式輸送機(jī)典型布置方式3 帶式輸送機(jī)的設(shè)計(jì)計(jì)算3.1 已知原始數(shù)據(jù)及工作條件帶式輸送機(jī)的設(shè)計(jì)計(jì)算，應(yīng)具有下列原始數(shù)據(jù)及工作條件資料（1）物料的名稱和輸送能力： （2）物料的性質(zhì)：1） 粒度大小，最大粒度和粗度組成情況；2） 堆積密度；3） 動堆積角、靜堆積角，溫度、濕度、粒度和磨損性等。（3）工作環(huán)境、露天、室內(nèi)、干燥、潮濕和灰塵多少等；（4）卸料方式和卸料裝置形式；（5）給料點(diǎn)數(shù)目和位置；（6）輸送機(jī)布置形式和尺寸，即輸送機(jī)系統(tǒng)（單機(jī)或多機(jī)）綜合布置形式、地形條件和供電情況。輸送距離、上運(yùn)或下運(yùn)、提升高度、最大傾角等；（7）裝置布置形式，是否需要設(shè)置制動器。原始參數(shù)和工作條件（1）輸送物料：煤（2）物料特性： 1）塊度：0300mm2）散裝密度：0.90t/3）在輸送帶上堆積角：=204）物料溫度：故摩擦條件滿足。3.5 輸送帶的強(qiáng)度驗(yàn)算（1）輸送帶的計(jì)算安全系數(shù) 由式。（2）輸送帶的許用安全系數(shù)表3-12 基本安全系數(shù)與表帶芯材料工作條件基本安全系數(shù)m0彎曲伸長系數(shù)cw有利3.2織物芯帶正常3.51.5不利3.8有利2.8剛繩芯帶正常31.8有利3.2可知 =3.0，=1.8，取=1.2，=0.95，得繩芯要求的縱向拉伸強(qiáng)度按式（3.5-1）計(jì)算； （3.5-1）式中靜安全系數(shù)，一般=710。運(yùn)行條件好，傾角好，強(qiáng)度低取小值；反之，取大值。輸送帶的最大張力24442 N選為7,由式（3.5-6） N/mm可選輸送帶為ST1000,滿足要求表3-15鋼絲繩輸送帶技術(shù)規(guī)格輸送帶型號ST1000鋼絲繩最大直徑/mm4縱向拉伸強(qiáng)度N/mm1000鋼絲繩間距/mm12帶厚/mm16上覆蓋膠厚度/mm6下覆蓋膠厚度/mm6輸送帶質(zhì)量kg/23.13.6 傳動滾筒、改向滾筒合張力計(jì)算3.6.1 改向滾筒合張力計(jì)算根據(jù)計(jì)算出的各特性點(diǎn)張力,計(jì)算各滾筒合張力。頭部180改向滾筒的合張力:=20878+21921=42799N 尾部180改向滾筒的合張力:=9790+10280=20070N 3.6.2 傳動滾筒合張力計(jì)算根據(jù)各特性點(diǎn)的張力計(jì)算傳動滾筒的合張力:動滾筒合張力:=21926+7526=29452N3.6.3 傳動滾筒最大扭矩計(jì)算單驅(qū)動時,傳動滾筒的最大扭矩按式（3.6-1）計(jì)算： （3.6-1）式中D傳動滾筒的直徑（mm）。 雙驅(qū)動時,傳動滾筒的最大扭矩按式（3.6-2）計(jì)算： （3.6-2）初選傳動滾筒直徑為630mm,則傳動滾筒的最大扭矩為:=29.452kN=9.27kN/m 3.7 拉緊裝置的設(shè)計(jì)計(jì)算3-16 常用輸送帶的延伸率與接頭長度表膠帶種類彈性延伸率懸垂度率接頭長度面帆布帶0.010.0012尼龍膠帶0.020.012鋼繩芯膠帶0.00250.0011拉緊裝置行程 由式 式中拉緊裝置行程，；輸送機(jī)長度，； 輸送帶的彈性延伸率; 輸送帶的懸垂度率; 輸送帶的接頭長度，;查上表選0.0025, =0.001, =0.7m,代入上式得：l300(0.0025+0.001)+1=2.05m, 令l2.5。 拉緊裝置拉緊力按式（3.7-1）計(jì)算 （3.7-1）式中拉緊滾筒趨入點(diǎn)張力（N）；拉緊滾筒奔離點(diǎn)張力（N）。由式（3.7-1）=8179.96+8588.96=16768 N =16.79 kN查機(jī)械設(shè)計(jì)手冊初步選定DT03D2103垂直重錘拉緊裝置。4 驅(qū)動裝置的選用與設(shè)計(jì)帶式輸送機(jī)的負(fù)載是一種典型的恒轉(zhuǎn)矩負(fù)載，而且不可避免地要帶負(fù)荷起動和制動。電動機(jī)的起動特性與負(fù)載的起動要求不相適應(yīng)在帶式輸送機(jī)上比較突出，一方面為了保證必要的起動力矩，電機(jī)起動時的電流要比額定運(yùn)行時的電流大67倍，要保證電動機(jī)不因電流的沖擊過熱而燒壞，電網(wǎng)不因大電流使電壓過分降低，這就要求電動機(jī)的起動要盡量快，即提高轉(zhuǎn)子的加速度，使起動過程不超過35s。驅(qū)動裝置是整個皮帶輸送機(jī)的動力來源，它由電動機(jī)、偶合器，減速器 、聯(lián)軸器、傳動滾筒組成。驅(qū)動滾筒由一臺或兩臺電機(jī)通過各自的聯(lián)軸器、減速器、和鏈?zhǔn)铰?lián)軸器傳遞轉(zhuǎn)矩給傳動滾筒。減速器有二級、三級及多級齒輪減速器，第一級為直齒圓錐齒輪減速傳動，第二、三級為斜齒圓柱齒輪降速傳動，聯(lián)接電機(jī)和減速器的連軸器有兩種，一是彈性聯(lián)軸器，一種是液力聯(lián)軸器。為此，減速器的錐齒輪也有兩種；用彈性聯(lián)軸器時，用第一種錐齒輪，軸頭為平鍵連接；用液力偶合器時，用第二種錐齒輪，軸頭為花鍵齒輪聯(lián)接。傳動滾筒采用焊接結(jié)構(gòu)，主軸承采用調(diào)心軸承，傳動滾筒的機(jī)架與電機(jī)、減速器的機(jī)架均安裝在固定大底座上面，電動機(jī)可安裝在機(jī)頭任一側(cè)。4.1 電機(jī)的選用 4.1.1 電動機(jī)功率計(jì)算電動機(jī)功率，按式（4.1-1）計(jì)算： （4.1-1）式中傳動效率，一般在0.850.95之間選?。宦?lián)軸器效率；每個機(jī)械式聯(lián)軸器效率：=0.98液力耦合器器：=0.96；減速器傳動效率，按每級齒輪傳動效率.為0.98計(jì)算；二級減速機(jī)：=0.980.98=0.96三級減速機(jī)：=0.980.980.98=0.94電壓降系數(shù)，一般取0.900.95。多電機(jī)功率不平衡系數(shù)，一般取，單驅(qū)動時，。根據(jù)計(jì)算出的值，查電動機(jī)型譜，按就大不就小原則選定電動機(jī)功率。由=28749.31W由式（4.1-1）=34535.9W選電動機(jī)型號為YB225S-4，N=37 kW。擬采用YB225S型電動機(jī)，該型電機(jī)轉(zhuǎn)矩大，性能良好，可以滿足要求。查運(yùn)輸機(jī)械設(shè)計(jì)選用手冊，它的主要性能參數(shù)如下表：表4-1 YB225S型電動機(jī)主要性能參數(shù)電動機(jī)型號額定功率kw滿載轉(zhuǎn)速r/min電流A效率功率因數(shù)YB225S-37148069.891.80.87起動電流/額定電流起動轉(zhuǎn)矩/額定轉(zhuǎn)矩最大轉(zhuǎn)矩/額定轉(zhuǎn)矩重量kg7.01.92.23604.2 減速器的選用 4.2.1 傳動裝置的總傳動比已知輸送帶寬為800，查運(yùn)輸機(jī)械選用設(shè)計(jì)手冊表277選取傳動滾筒的直徑D為630，則工作轉(zhuǎn)速為： ， (4.2-1)已知電機(jī)轉(zhuǎn)速為1480 r/min ，則電機(jī)與滾筒之間的總傳動比為： (4.2-2)選擇DCY型減速器。選擇型號查機(jī)械設(shè)計(jì)手冊3表18.1-38選DCY型減速器承載能力。選用 DCY250-31.5傳動比為31.5，可傳遞85KW功率。第一級為螺旋齒輪，第二級、第三級為斜齒和直齒圓柱齒輪傳動，其展開簡圖如下：圖4-1 減速器展開簡圖電動機(jī)和I軸之間，IV軸和傳動滾筒之間用的都是聯(lián)軸器，故傳動比都是1。故選用一臺Y225S-4型電機(jī), DCY250-31.5型礦用減速器,查表2-119,驅(qū)動裝置選取耦合器YOX400,耦合器護(hù)罩YFZ-45.驅(qū)動裝置號Q44JZ1119，驅(qū)動裝置架JZ44IZ1095其他具體尺寸按表選取。4.3 液力偶合器液力傳動與液壓傳動一樣，都是以液體作為傳遞能量的介質(zhì)，同屬液體傳動的范疇，二者的重要區(qū)別在于，液壓傳動是同過工作腔容積的變化，是液體壓力能改變傳遞能量的；液力傳動是利用旋轉(zhuǎn)的葉輪工作，輸入軸與輸出軸為非剛性連接，通過液體動能的變化傳遞能量，傳遞的紐矩與其轉(zhuǎn)數(shù)的平方成正比目前，在帶式輸送機(jī)的傳動系統(tǒng)中，廣泛使用液力偶合器，它安裝在輸送機(jī)的驅(qū)動電機(jī)與減速器之間，電動機(jī)帶動泵輪轉(zhuǎn)動，泵輪內(nèi)的工作液體隨之旋轉(zhuǎn)，這時液體繞泵輪軸線一邊作旋轉(zhuǎn)運(yùn)動，一邊因液體受到離心力而沿徑向葉片之間的通道向外流動，到外緣之后即進(jìn)入渦輪中，泵輪的機(jī)械能轉(zhuǎn)換成液體的動能，液體進(jìn)去渦輪后，推動渦輪旋轉(zhuǎn)，液體被減速降壓，液體的動能轉(zhuǎn)換成渦輪的機(jī)械能而輸出作功它是依靠液體環(huán)流運(yùn)動傳遞能量的，而產(chǎn)生環(huán)流的先決條件是泵輪的轉(zhuǎn)速大于渦流轉(zhuǎn)速，即而者之間存在轉(zhuǎn)速差液力傳動裝置除煤礦機(jī)械使用外，還廣泛用于各種軍用車輛，建筑機(jī)械，工程機(jī)械，起重機(jī)械，載重汽車小轎車和艦艇上，它所以獲得如此廣泛的應(yīng)用，原因是它具有以下多種優(yōu)點(diǎn)：） 能提高設(shè)備的使用壽命） 由于液力轉(zhuǎn)動的介質(zhì)是液體，輸入軸與輸出軸之間用非剛性連接，故能將外載荷突然驟增或驟減造成的沖擊和振動消除或部分消除，轉(zhuǎn)化為連續(xù)連續(xù)漸變載荷，從而延長機(jī)器的使用壽命這對處于惡劣條件下工作的煤礦機(jī)械具有這樣意義） 有良好的啟動性能由于泵輪扭矩與其轉(zhuǎn)速的平方成正比，故電動機(jī)啟動時其負(fù)載很小，起動較快，沖擊電流延續(xù)時間短，減少電機(jī)發(fā)熱） 良好的限矩保護(hù)性能） 使多電機(jī)驅(qū)動的設(shè)備各臺電機(jī)負(fù)荷分配趨于均勻本次設(shè)計(jì)選用的YOX II400，輸入轉(zhuǎn)速為1480rmin，效率達(dá)0.96，起動系數(shù)為1.31.7。4.4 聯(lián)軸器本次驅(qū)動裝置的設(shè)計(jì)中，較多的采用聯(lián)軸器，這里對其做簡單介紹：聯(lián)軸器是機(jī)械傳動中常用的部件。它用來把兩軸聯(lián)接在一起，機(jī)器運(yùn)轉(zhuǎn)時兩軸不能分離；只有在機(jī)器停車并將聯(lián)接拆開后，兩軸才能分離。根據(jù)對各種相對位移有無補(bǔ)償能力（即能否在發(fā)生相對位移條件下保持聯(lián)接的功能），聯(lián)軸器可分為剛性聯(lián)軸器（無補(bǔ)償能力）和撓性聯(lián)軸器（有補(bǔ)償能力）兩大類。撓性聯(lián)軸器又可按是否具有彈性元件分為無彈性元件的撓性聯(lián)軸器和有彈性元件的撓性聯(lián)軸器兩個類別。剛性聯(lián)軸器這類聯(lián)軸器有套筒式、夾殼式和凸緣式等。凸緣聯(lián)軸器是把兩個帶有凸緣的半聯(lián)軸器聯(lián)成一體，以傳遞運(yùn)動和轉(zhuǎn)矩。凸緣聯(lián)軸器的材料可用灰鑄鐵或碳鋼，重載時或圓周速度大于30m/s時應(yīng)用鑄鋼或碳鋼。由于凸緣聯(lián)軸器屬于剛性聯(lián)軸器，對所聯(lián)兩軸的相對位移缺乏補(bǔ)償能力，故對兩軸對中性的要求很高。當(dāng)兩軸有相對位移存在時，就會在機(jī)件內(nèi)引起附加載荷，使工作情況惡化，這是它的主要缺點(diǎn)。但由于構(gòu)造簡單、成本低、可傳遞較大轉(zhuǎn)矩，故當(dāng)轉(zhuǎn)速低、無沖擊、軸的剛性大、對中性較好時亦常采用。本次設(shè)計(jì)中選擇GYS11型凸緣聯(lián)軸器。安裝在傳動滾筒與減速器之間。撓性聯(lián)軸器 (1)無彈性元件的撓性聯(lián)軸器這類聯(lián)軸器因具有撓性，故可補(bǔ)償兩軸的相對位移。但因無彈性元件，故不能緩沖減振。常用的有以下幾種：十字滑塊聯(lián)軸器，滑塊聯(lián)軸器，十字軸式萬向聯(lián)軸器，齒式聯(lián)軸器，滾子鏈聯(lián)軸器。 (2)有彈性元件的撓性聯(lián)軸器這類聯(lián)軸器因裝有彈性元件，不僅可以補(bǔ)償兩軸間的相對位移，而且具有緩沖減振的能力，常見的有以下幾種：1）彈性套柱銷聯(lián)軸器這種聯(lián)軸器的構(gòu)造與凸緣聯(lián)軸器相似，只是套有彈性套的柱銷代替了聯(lián)接螺栓。因?yàn)橥ㄟ^蛹狀的彈性套傳遞轉(zhuǎn)矩，故可緩沖減振。這種聯(lián)軸器制造容易，裝拆方便，成本較低，但彈性套易磨損，壽命較短。他適用于聯(lián)接載荷平穩(wěn)、需正反轉(zhuǎn)或起動頻繁的傳遞中小轉(zhuǎn)矩的軸。2） 彈性柱銷聯(lián)軸器與彈性套柱銷聯(lián)軸器很相似，但傳遞轉(zhuǎn)矩的能力很大，結(jié)構(gòu)更為簡單，安裝、制造方便，耐久性好，也有一定的緩沖和吸振能力，允許被聯(lián)接兩軸有一定的軸向位移以及少量的徑向位移和角位移，適用于軸向竄動較大、正反轉(zhuǎn)變化較多和起動頻繁的場合柱銷聯(lián)軸器。3）梅花形彈性聯(lián)軸器這種聯(lián)軸器的半聯(lián)軸器與軸的配合孔可作成圓柱形或圓錐形。裝配聯(lián)軸器時將梅花形彈性件的花瓣部分夾緊在兩半聯(lián)軸器端面凸齒交錯插進(jìn)所形成的齒側(cè)空間，以便在聯(lián)軸器工作時起到緩沖減振的作用。圖4-2梅花形彈性聯(lián)軸器5 帶式輸送機(jī)部件的選用5.1 輸送帶輸送帶在帶式輸送機(jī)中既是承載構(gòu)件又是牽引構(gòu)件（鋼絲繩牽引帶式輸送機(jī)除外），它不僅要有承載能力，還要有足夠的抗拉強(qiáng)度。輸送帶有帶芯（骨架）和覆蓋層組成，其中覆蓋層又分為上覆蓋膠，邊條膠，下覆蓋膠。輸送機(jī)的帶芯主要是有各種織物（棉織物，各種化纖織物以及混紡織物等）或鋼絲繩構(gòu)成。它們是輸送帶的骨干層，幾乎承載輸送帶工作時的全部負(fù)載。因此，帶芯材料必須有一定的強(qiáng)度和剛度。覆蓋膠用來保護(hù)中間帶芯不受機(jī)械損傷以及周圍有害介質(zhì)的影響。上覆蓋膠層一般較厚，這是輸送帶的承載面，直接與物料接觸并承受物料的沖擊和磨損。下覆膠層是輸送帶與支撐托輥接觸的一面，主要承受壓力，為了減少輸送帶沿托輥運(yùn)行時的壓陷阻力，下覆蓋膠的厚度一般較薄。側(cè)邊覆蓋膠的作用是當(dāng)輸送帶發(fā)生跑偏使側(cè)面與機(jī)架相碰時，保護(hù)帶芯不受機(jī)械損傷。 5.1.1 輸送帶的分類按輸送帶帶芯結(jié)構(gòu)及材料不同，輸送帶被分成織物層芯和鋼絲繩芯兩大類?？椢飳有居址譃榉謱涌椢镄竞驼w織物層層芯兩類，且織物層芯的材質(zhì)有棉，尼龍和維綸等。整體編織織物層芯輸送帶與分層織物層芯輸送帶相比，在帶強(qiáng)度相同的情況下，整體輸送帶的厚度小，柔性好，耐沖擊性好，使用中不會發(fā)生層間剝裂，但伸長率較高，在使用過程中，需要較大的拉緊行程。鋼絲繩芯輸送帶是有許多柔軟的細(xì)鋼絲繩相隔一定的間距排列，用與鋼絲繩有良好粘合性的膠料粘合而成。鋼絲繩芯輸送帶的縱向拉伸強(qiáng)度高，抗彎曲性能好；伸長率小，需要拉緊行程小。同其它輸送帶相比，在帶強(qiáng)度相同的前提下，鋼絲繩芯輸送帶的厚度小。在鋼芯繩中,鋼絲繩的質(zhì)量是決定輸送帶使用壽命長短的關(guān)鍵因素之一，必須具有以下特點(diǎn)：(1)應(yīng)具有較高的破斷強(qiáng)度。鋼芯強(qiáng)度高則輸送帶亦可增大，從另一個角度來說，繩芯強(qiáng)度越高，所用繩之直徑即可縮小，輸送帶可以做的薄些，已達(dá)到減小輸送機(jī)尺寸的目的。(2)繩芯與橡膠應(yīng)具有較高的黏著力。這對于用硫化接頭具有重大意義.提高鋼繩與橡膠之間黏著力的主要措 本科畢業(yè)設(shè)計(jì)（論文）中期檢查表指導(dǎo)教師： 職稱： 講師 所在院（系）： 機(jī)械與動力工程學(xué)院 教研室（研究室）： 機(jī)械設(shè)計(jì) 題 目DTII（A）型帶式輸送機(jī)學(xué)生姓名 專業(yè)班級學(xué)號一、選題質(zhì)量：（主要從以下四個方面填寫：1、選題是否符合業(yè)培養(yǎng)目標(biāo)，能否體現(xiàn)綜合訓(xùn)練要求；2、題目難易程度；3、題目工作量；4、題目與生產(chǎn)、科研、經(jīng)濟(jì)、社會、文化及實(shí)驗(yàn)室建設(shè)等實(shí)際的結(jié)合程度）1、本題目符合機(jī)械設(shè)計(jì)及制造專業(yè)培養(yǎng)目標(biāo)，能充分鍛煉和培養(yǎng)生產(chǎn)實(shí)際中分析問題的能力與動手操作能力，能充分培養(yǎng)學(xué)生的能力和各方面專業(yè)素質(zhì)的提高。2、本題目難易適中，適合學(xué)生獨(dú)立完成題目，符合本科畢業(yè)設(shè)計(jì)要求。3、本題目工作量適中，能在規(guī)定時間內(nèi)完成。4、本題目與生產(chǎn)、經(jīng)濟(jì)等方面聯(lián)系比較緊密，輸送機(jī)應(yīng)用領(lǐng)域廣泛，經(jīng)濟(jì)生產(chǎn)過程不可或缺。二、開題報告完成情況：從適合實(shí)際工作環(huán)境出發(fā)，確立了明確的課題設(shè)計(jì)方向；通過查閱有關(guān)輸送機(jī)的相關(guān)資料與文獻(xiàn)，基本了解輸送機(jī)的設(shè)計(jì)要求；并對輸送機(jī)在使用中常出現(xiàn)的問題有一定的研究，且應(yīng)用在設(shè)計(jì)計(jì)算中；已經(jīng)開始對課題進(jìn)行設(shè)計(jì)計(jì)算,并有了突破性的進(jìn)展，設(shè)計(jì)過程已經(jīng)快速地展開，確定了工作的內(nèi)容和方法；經(jīng)過指導(dǎo)老師的耐心指導(dǎo)，做出了完整的開題報告，并且通過了指導(dǎo)老師的審批。三、階段性成果： 1. 收集了大量關(guān)于輸送機(jī)的資料，完成了外文資料翻譯，撰寫了開題報告。2. 確定了設(shè)計(jì)方案，及主要設(shè)計(jì)參數(shù)。3. 進(jìn)行了設(shè)計(jì)計(jì)算，并校核。4. 根據(jù)主要參數(shù)繪制出主要零件的圖紙，并一步步趨于完善。四、存在主要問題：1.對軟件的應(yīng)用不熟悉，資料收集不夠全，有些技術(shù)參數(shù)不太明白，導(dǎo)致進(jìn)度放慢；2.輸送帶的運(yùn)行速度受到物料性質(zhì)和帶寬的限制，其中物料性質(zhì)的限制最大；3.局部結(jié)構(gòu)設(shè)計(jì)思路不清晰，設(shè)計(jì)內(nèi)容不夠連貫，系統(tǒng)性不強(qiáng)，在選用零件和確定結(jié)構(gòu)工藝參數(shù)時缺少經(jīng)驗(yàn)和參考。五、指導(dǎo)教師對學(xué)生在畢業(yè)實(shí)習(xí)中，勞動、學(xué)習(xí)紀(jì)律及畢業(yè)設(shè)計(jì)（論文）進(jìn)展等方面的評語指導(dǎo)教師： （簽名） 年 月 日3畢業(yè)設(shè)計(jì)外文資料與中文翻譯外文資料：Design of High Speed Belt ConveyorsG. Lodewi jks, The Netherlands.SUMMARYThis paper discusses aspects of high-speed belt conveyor design. The capacity of a belt conveyor is determined by the belt speed given a belt width and troughing angle. Belt speed selection however is limited by practical considerations, which are discussed in this paper. The belt speed also affects the performance of the conveyor belt, as for example its energy consumption and the stability of its running behavior. A method is discussed to evaluate the energy consumption of conveyor belts by using the loss factor of transport. With variation of the belt speed the safety factor requirements vary, which will affect the required belt strength. A new method to account for the effect of the belt speed on the safety factor is presented. Finally, the impact of the belt speed on component selection and on the design of transfer stations is discussed.1 INTRODUCTIONPast research has shown the economical feasibility of using narrower, faster running conveyor belts versus wider, slower running belts for long overland belt conveyor systems. See for example I-5. Today, conveyor belts running at speeds around 8 m/s are no exceptions. However, velocities over 10 m/s up to 20 m/s are technically (dynamically) feasible and may also be economically feasible. In this paper belt speeds between the 10 and 20 m/s are classified as high. Belt speeds below the 10 m/s are classified as low.Using high belt speeds should never be a goal in itself. If using high belt speeds is not economically beneficial or if a safe and reliable operation is not ensured at a high belt speed then a lower belt speed should be selected.Selection of the belt speed is part of the total design process. The optimum belt conveyor design is determined by static or steady state design methods. In these methods the belt is assumed to be a rigid, inelastic body. This enables quantification of the steady-state operation of the belt conveyor and determination of the size of conveyor components. The specification of the steady-state operation includes a quantification of the steady-state running belt tensions and power consumption for all material loading and relevant ambient conditions. It should be realized that finding the optimum design is not a one-time effort but an iterative process 6.This paper discusses the design of high belt-speed conveyors, in particular the impact of using high belt speeds on the performance of the conveyor belt in terms of energy consumption and safety factor requirements. Using high belt speeds also requires high reliability of conveyor components such as idlers to achieve an acceptable component life. Another important aspect of high-speed belt conveyor design is the design of efficient feeding and discharge arrangements. These aspects will be discussed briefly.2 BELTSPEED2.1 BELT SPEED SELECTIONThe lowest overall belt conveyor cost occur in the range of belt widths of 0.6 to 1.0 m 2. The required conveying capacity can be reached by selection of a belt width in this range and selecting whatever belt speed is required to achieve the required flow rate. Figure 1 shows an example of combinations of belt speed and belt width to achieve Specific conveyor capacities. In this example it is assumed that the bulk density is 850 kg/m3 (coal) and that the trough angle and the surcharge angle are 35 and 20 respectively.Belt speed selection is however limited by practical considerations. A first aspect is the troughability of the belt. In Figure 1 there is no relation with the required belt strength (rating), which partly depends on the conveyor length and elevation. The combination of belt width and strength must be chosen such that good troughability of the belt is ensured. If the troughability is not sufficient then the belt will not track properly. This will result in unstable running behavior of the belt, in particular at high belt speeds, which is not acceptable. Normally, belt manufacturers expect a sufficiently straight run if approximately 40% of the belt width when running empty, makes contact with the carrying idlers. Approximately 10% should make tangential contact with the center idler roll.A second aspect is the speed of the air relative to the speed of the bulk solid material on the belt (relative airspeed). If the relative airspeed exceeds certain limits then dust will develop. This is in particular a potential problem in mine shafts where a downward airflow is maintained for ventilation purposes. The limit in relative airspeed depends on ambient conditions and bulk material characteristics.A third aspect is the noise generated by the belt conveyor system. Noise levels generally increase with increasing belt speed. In residential areas noise levels are restricted to for example 65 dB. Although noise levels are greatly affected by the design of the conveyor support structure and conveyor covers, this may be a limiting factor in selecting the belt speed.2.2 BELT SPEED VARIATIONThe energy consumption of belt conveyor systems varies with variation of the belt speed, as will be shown in Section 3. The belt velocity can be adjusted with bulk material flow supplied at the loading point to save energy. If the belt is operating at full tonnage then it should run at the high (design) belt speed. The belt speed can be adjusted (decreased) to the actual material (volume) flow supplied at the loading point. This will maintain a constant filling of the belt trough and a constant bulk material load on the belt. A constant filling of the belt trough yields an optimum loading-ratio, and lower energy consumption per unit of conveyed material may be expected. The reduction in energy consumption will be at least 10% for systems where the belt speed is varied compared to systems where the belt speed is kept constant 8.3 ENERGY CONSUMPTION3.1 TRANSPORT EFFICIENCYThere are a number of methods to compare transport efficiencies. The first and most widely applied method is to compare equivalent friction factors such as the DIN f factor. An advantage of using an equivalent friction factor is that it can also be determined for an empty belt. A drawback of using an equivalent friction factor is that it is not a pure efficiency number. It takes into account the mass of the belt, reduced mass of the rollers and the mass of the transported material. In a pure efficiency number, only the mass of the transported material is taken into account.The second method is to compare transportation cost, either in kW-hr/ton/km or in $/ton/km. The advantage of using the transportation cost is that this number is widely used for management purposes. The disadvantage of using the transportation cost is that it does not directly reflect the efficiency of a system.The third and most pure method is to compare the loss factor of transport 10. The loss factor of transport is the ratio between the drive power required to overcome frictional losses (neglecting drive efficiency and power loss/gain required to raise/lower the bulk material) and the transport work. The transport work is defined as the multiplication of the total transported quantity of bulk material and the average transport velocity. The advantage of using loss factors of transport is that they can be compared to loss factors of transport of other means of transport, like trucks and trains. The disadvantage is that the loss factor of transport depends on the transported quantity of material, which implies that it can not be determined for an empty belt conveyor.The following are loss factors of transport for a number of transport systems to illustrate the concept:3.2 INDENTATION ROLLING RESISTANCEIt is important to know how the indentation rolling resistance depends on the belt velocity to enable selection of a proper belt velocity, 11. load on the belt decreases with a factor 2 then the indentation rolling resistance decreases with a factor 2.52 (2 4/3). The bulk load decreases with increasing belt speed assuming a constant capacity. Therefore, the indentation rolling resistance decreases more than proportionally with increasing belt speed.Secondly, the indentation rolling resistance depends on the size of the idler rolls. If the roll diameter increases with a factor 2 then the indentation rolling resistance decreases with a factor 1.58 (2 2/3). In general the idler roll diameter increases with increasing belt speed to limit the bearing rpms to maintain acceptable idler life. In that case the indentation rolling resistance decreases with increasing belt speed.Thirdly, the indentation rolling resistance depends on the visco-elastic properties of the belts cover material. These properties depend on the deformation rate, see Figure 3. The deformation rate in its turn depends on the size of the deformation area in the belts bottom cover (depending on belt and bulk load) and on the belt speed. In general the indentation rolling resistance increases with increasing deformation rate (and thus belt speed), but only to a relatively small account.Fourthly, the indentation rolling resistance depends on the belts bottom cover thickness. If the bottom cover thickness increases with a factor 2 then the indentation rolling resistance increases with a factor 1.26 (2 1/3). if a bottom cover is increased to account for an increase in belt wear with increasing belt speed, then the indentation rolling resistance increases as well.It should be realized that the indentation rolling resistance, although important, is not the only velocity dependent resistance. The rolling resistance of the idler rolls for example depends on the vertical load as well as on their rotational speed. The effect of the vertical load, which directly depends on the belt speed, is large. The effect of the rotational speed is much smaller. Another resistance occurs due to acceleration of the bulk solid material at the loading point. This resistance increases quadratically with an increase in belt speed assuming that the bulk material falls straight onto the belt. This will affect smaller, in plant belt conveyors in particular.3.3 RUBBER COMPOUNDSThe indentation rolling resistance depends on the visco-elastic properties of the belts bottom cover as discussed in the preceding section. This implies that the rolling resistance can be decreased by selecting a special low indentation rolling resistance (rubber) compound that is available on the market today. A small premium has to be paid for this special compound, but costs can be limited by applying it for the bottom cover only and using a normal wear-resistant compound for the carrying top cover. In that case turnovers are required to fully use the energy saving function of the bottom compound.A Quantitative indication of the level of indentation rolling resistance is the indentation rolling resistance indicator tan/E 1/3, where tan is the loss angle and E the storage modulus of the compound. Compounds with a reasonable indentation rolling resistance performance have indicators below 0.1. Figure 8 shows these indicators for typical medium to good performing rubbers. As can be seen in that figure, the choice for a specific rubber compound affects the energy consumption of the belt conveyor, in particular as a function of the ambient temperature.One comment (warning) must be made. A special belt with low indentation rolling resistance compound should never be selected if only one conveyor belt manufacturer offers it. In that case the conveyor system can only perform in accordance with its design specifications when that specific belt is used. It is much better, also cost wise, to specify the upper limit of the resistance indicator as given above that can be met by more than one conveyor belt manufacturer.Figure 1: Indentation rolling resistance indicators for fourdifferent rubbers as a function of temperature.4. SAFETY FACTOR REQUIREMENTSFor design purposes, standards like DIN 22101, ISO 5048 and CEMA provide safety factors (SF) that limit the permissible belt loads. Two types of safety factors can be distinguished: safety factors on the steady-state running tensions and safety factors on the non-stationary tensions. standards like the DIN standard base the recommended safety factor on reduction factors. DIN 22101 uses three reduction factors. The first (r0) generally accounts for the reduction of the strength of the belt (splices) due to fatigue. The second (r1) accounts for the extra forces that act on the belt in transition zones and on pulleys etc. The third (r2) accounts for the extra dynamic stresses in the belt during starting and stopping. The required minimum safety factor can be calculated as follows:SF=1/(1-(r0+r1+r2) (1)The DIN standard also gives values for the three reduction factors. For example, for a steel cord conveyor belt under normal operational conditions the values are as follows: r00.665, r10.15, r20.06, which yields a safety factor SF8.Although much can be said about the applicability of the safety factor determined with the DIN standard for the design of long belt conveyor systems, the major drawback, keeping the belt speed selection in mind, is that the conveyor systems operational data and the real fatigue properties of the belt are not taken into account.It is possible to account for these factors and to achieve a tailor-made safety factor by taking the belts operational data into account. The reduction factors r1 and r2 are independent of the fatigue properties of the belt and thus constant with increasing number of load cycles. Lets assume that the reduction factor r0 varies linearly with the log1O of the number of load cycles (revolution of the belt through the total belt conveyor) from 0 to 0.665 at 10,000 load cycles (approximation of DIN standard):r0= 0.166 log10(N) (N10.000) (2)where N is the number of load cycles. After 10,000 load cycles r0 hardly increases. Now lets assume that the conveyor under design has a length of 10,000 m, a life expectation of 5 years at 5000 operational hours per year. The total number of load cycles can be calculated with the following equation:N=(3600 V)/(2L)HY (3)where V is the belt speed, L the conveyor length, H the number of operational hours per year and Y the number of expected years of operation. Equation (3) is visualized in Figure 2Figure 2: Number of load cycles versus belt speed for given example.The value of the reduction factor ro can be determined with equation (2) and the number of load cycles as given in Figure 2 The result is shown in Figure 3.Figure 3: DIN 22101 reduction factor r0 for given exampleThe safety factor as a function of the belt speed then can be determined with equation (1) and Figure 3. The result is shown in Figure 4.Figure 4: Minimum required safety factor for given exampleFrom Figure 4 it can be learned that for the belt under design the required minimum safety factor on the steady-state running tensions is about 7.5 if the belt is running at 2 m/s, and about 10 in case the belt is running at 20 m/s. Taking the belt speed into account during safety factor determination thus prevents overrating of the belt at low speeds and underrating at high speeds (also depends on the length of the conveyor system).The above given figures and numbers are to illustrate the procedure only. This procedure can be fine tuned by taking measured fatigue properties of the belt tensile-carrying member (steel cords or fabric) and the rubber into account, as well as the actual load cycle of the belt (empty, fully loaded, steady state running, starting and stopping, summer, and winter conditions etc.).5 BELT CONVEYOR DYNAMICSIn essence the dynamics of a belt conveyor does not change with the belt speed. However, with increasing belt speed the rate of changes increases, which will result in a decreasing running stability of the belt. This paper is not intended to fully discuss belt conveyor dynamics. It is referred to 7 where this topic is extensively discussed. However, a number of notes on the dynamics of high belt speed conveyors can be made.When a belt between two idlers is exited by an idler roll in or near a natural frequency of transverse vibration of the belt span, resonance phenomena occur. The amplitude of transverse vibration increases considerably when resonance occurs yielding increased roll/ bearing wear and an increased power consumption of the belt. This increase in vibration amplitude, also referred to as belt flap, must be avoided. In high-speed belt systems the effect of resonance on the structure is very destructive, as observed with lower speed belts that resonate and destroy idler bearings. Care should therefore be taken to design a belt conveyor so that the possibility of resonance in the belt is avoided and at the same time best use is made of current static design methods so that the economics of the design are saved.Belt tracking must be excellent at high speeds. If the belt does not track properly then run off may be expected since, with increasing belt speed, side displacements and the rate of side displacement increase. The combination of belt width and strength must be chosen such that good troughability is ensured, see Section 2.1. Also maximum effort must be made by the belt manufacturer to make straight belts and to construct true belt splices. In addition, longer manufactured belt lengths reduce the number of splices and thus increase the chance of straightness.A similar comment can be made for the design of horizontal belt curves. The position of the belt on the idlers changes with a change in belt tension mainly due to a change in loading degree. The belt will move sideward in particular during large tension variations as occur during (aborted) starting and (emergency) stopping. The change in belt tension during starting and stopping will increase with increasing belt speed. For low belt speed conveyors static design methods may be sufficient to determine the maximum side displacement. For high belt speed conveyors however, dynamic design methods are required to predict the side displacement to a sufficient level of accuracy.Normal operational starting and stopping procedures will not change for high belt speed conveyors, except that starting and stopping will take more time. The nature of emergency stop procedures however will change. In general emergency stop procedures are designed to stop the belt in a short period of time without the use of the drive system and so that the belt conveyor is not damaged. A typical emergency stop time for a long overland conveyor is 30 seconds, which may be short enough to prevent casualties. However at high belt speeds the amount of energy (which increases quadratically with increasing belt speed) that has to be transferred from the conveyor belt into a braking system is much higher, which will result in considerably longer emergency stopping times. Therefore the chance of casualties is much higher in case an emergency happens. For high belt speed conveyors it is therefore even more important to be equipped with appropriate safety guards.6 IDLER SELECTIONThe most important selection criterion of idlers for high-speed belt conveyors is the idler diameter. In general it can be said that the diameter of idlers will need to be increased for high speed belts compared to the diameter of idlers used in low-speed belts for a number of reasons including: with low rotational speed idler bearings can be used with L10 ratings that are currently available and used in low speed belt conveyors. This implies that currently used maintenance schedules can be followed. The diameter of an idler has a considerable effect on the idler performance. Together with the belt speed, it fixes the speed at which the idler, and thus the roller