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江西農(nóng)業(yè)大學(xué)畢業(yè)設(shè)計(論文)任務(wù)書
設(shè)計（論文）
課題名稱
果蔬收獲機器人的設(shè)計（機械部分)
學(xué)生姓名
院（系）
工學(xué)院
專 業(yè)
機械設(shè)計制造及其自動化
指導(dǎo)教師
職 稱
講師
學(xué) 歷
博士
畢業(yè)設(shè)計（論文）要求：
以某種瓜果類為具體的研究對象，從其生長方式、形狀等方面著手，設(shè)計一種多自由度果蔬收獲機器人，應(yīng)用于大型果蔬園，提高勞動生產(chǎn)率，降低成本。
該課題不考慮控制方面的設(shè)計，只限于機械結(jié)構(gòu)設(shè)計部分。
畢業(yè)設(shè)計（論文）內(nèi)容與技術(shù)參數(shù)：
1 摘要： 簡述論文的內(nèi)容。
2 緒論： 國內(nèi)外有關(guān)文獻(xiàn)綜述。
3 果蔬收獲機器人的總體結(jié)構(gòu)設(shè)計和運動原理
（包括實現(xiàn)每個自由度的結(jié)構(gòu)設(shè)計和運動原理）。
4 總結(jié)。
畢業(yè)設(shè)計（論文）工作計劃：
1 查閱有關(guān)的國內(nèi)外文獻(xiàn)，并認(rèn)真閱讀。
2 學(xué)習(xí)二維、三維繪圖軟件以及仿真軟件。
3 結(jié)合相關(guān)機器人的結(jié)構(gòu)設(shè)計特點，按要求創(chuàng)新地設(shè)
計一種多自由度果蔬收獲機器人。
4 按要求繪圖，打印圖紙。
5 參照論文撰寫格式撰寫論文。
6 5月20號之前完成答辯。
接受任務(wù)日期 年 月 日 要求完成日期 年 月 日
學(xué) 生 簽 名 年 月 日
指導(dǎo)教師簽名 年 月 日
院長（主任）簽名 年 月 日
大白菜收獲機的設(shè)計
學(xué)校代碼：
序 號：
本 科 畢 業(yè) 設(shè) 計
題目： 大白菜收獲機機械部分設(shè)計
——提升運輸機構(gòu)的設(shè)計
學(xué) 院： 工 學(xué) 院
姓 名：
學(xué) 號：
專 業(yè)： 機械設(shè)計制造及其自動化
年 級： 05級
指導(dǎo)教師：
二OO九年 五 月
摘 要
隨著新的農(nóng)業(yè)生產(chǎn)模式和新技術(shù)的發(fā)展與應(yīng)用，農(nóng)業(yè)機器人將成為農(nóng)業(yè)生產(chǎn)的主力軍。該文在分析大白菜收獲機工作特點的基礎(chǔ)上，從大白菜的采摘、轉(zhuǎn)運、打包等方面進行分析。其中主要對提升運輸部分做了詳細(xì)的設(shè)計說明。該大白菜收獲機適用于中小規(guī)模收割大白菜，結(jié)構(gòu)簡單、制造成本低。
該大白菜收獲機的提升運輸部分采用帶式輸送，而張緊裝置作為帶式輸送機構(gòu)中不可缺少的重要組成部分，對帶式輸送機的穩(wěn)定運行有著至關(guān)重要的作用。本文內(nèi)容包括機架設(shè)計方案，平帶帶輪和平帶的選擇，軸的校核，以及張緊裝置的作用、類型，且設(shè)計了張緊裝置的總體方案，對其主要零部件的設(shè)計和選型進行了說明。所設(shè)計的張緊裝置使用螺桿作為張緊執(zhí)行元件，具有張緊力可調(diào)、結(jié)構(gòu)簡單、適應(yīng)性強、控制方便、安全性能好等特點。
關(guān)鍵詞：大白菜、收獲機、帶式提升輸送裝置、張緊裝置、螺桿
Designing Of Hoisting And Transporting Mechanism
For Cabbage Harvest Machinery
Abstract
Farm machinery is to become the capital ship of the agriculture.This paper introduced gathering ,transporting and packing cabbage,on the basis of the working peculiarity of the cabbage harvest machinery,and it mainly introduced its transporting mechanism. The cabbage harvest machinery is suitable to gather in the cabbage for family expenses.
The cabbage harvest machinery use belt conveyors as its transporting mechanism,while Tensioning device, as an important and indispensable component of the belt conveyor, has a vital role to the stable operation of the belt conveyor . This paper introduces the role of the tensioning device,type,installation layout principles, and its development profile.And then raised the tension of the belt conveyor to the tension and take-up device requirements, on the basis the analysis of the principle of the transmission belt conveyor. In this paper, the main device design programme of the automatically tensioning device have been introduced, and descripte its main components for the design and selection of the note.The tensioning device use the screwstaff as the take-up of the implementation component.,with adjustable tension, simple, strong adaptability and control convenience, performance and safety and so on.
Keywords：Cabbage harvest； machinery； Belt hoisting and transporting mechanism； tensioning；Screwstaff
目 錄
1 緒論 1
2 大白菜收獲機總體和主要部件簡介。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。2
2.1. 大白菜收獲機工作原理和結(jié)構(gòu)簡介。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。2
2.2 收獲機提升運輸裝置簡介 2
2.3 其他裝置簡介................................................................................................................3
2.3.1 收獲機輸送部分簡介。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。3
2.3.2 鎖緊裝置簡介。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。4
3 提升運輸裝置主要零部件的設(shè)計 7
3.1 機架的設(shè)計 7
3.1.1 機架外形.......................................................................................................................7
3.1.2 計算部分.......................................................................................................................8
3.1.3 機架結(jié)構(gòu)的確定.........................................................................................................8
3.2平帶帶輪的設(shè)計 9
3.3平帶的選擇 10
3.4平帶帶輪軸的設(shè)計 11
3.4.1 主動軸的設(shè)計 11
3.4.2 從動軸的設(shè)計 13
3.5 端蓋.....................................................................................................................14
3.6 支承軸的設(shè)計.....................................................................................................14
4 結(jié)論 15
4.1主要結(jié)論 16
4.2 問題與展望 16
5 設(shè)計心得 17
參考文獻(xiàn) 18
致謝 19
1 緒 論
果蔬收獲屬于一類勞動密集型工作，在很多國家，由于勞動力的高齡化，人力資源越來越缺乏，勞動力不僅成本高，而且還不容易得到，而人工收獲的成本在果蔬的整個生產(chǎn)成本中所占的比例高達(dá)33%～50%。因此實現(xiàn)果蔬收獲的機械化變得越來越迫切。
設(shè)計收獲機時，須考慮以下幾個問題：1）農(nóng)民一般不具備太多的專業(yè)知識，因此收獲機必須結(jié)構(gòu)簡單、操作性好、可靠性高、并且價格合理。2）由于大白菜葉球很脆嫩，在裝運過程中，很難避免外力的碰撞、擠壓而出現(xiàn)傷口。出現(xiàn)機械損傷不但影響商品價值，而且易腐爛變質(zhì)。因此合理地設(shè)計收獲機的作業(yè)過程至關(guān)重要。
本設(shè)計通過對帶式提升輸送機起動張緊力和正常運行張緊力的計算，分析了帶式提升輸送機對張緊裝置的要求，比較了各種張緊裝置對帶式輸送機的影響，深入研究了張緊裝置的組成部分和其工作原理、工作環(huán)境、工況要求，并針對收獲機的輸送機構(gòu)，設(shè)計了一種螺旋張緊裝置，即通過螺桿移動張緊滾筒實現(xiàn)張緊目的，實現(xiàn)了張緊力的調(diào)節(jié)。同時對提升運輸機構(gòu)其他零部件的選擇也做了詳細(xì)的說明。
2 大白菜收獲機總體和主要部件簡介
2.1 大白菜收獲機工作原理和總體結(jié)構(gòu)簡介
收獲機的工作過程為：扶莖器將大白菜扶正，切削刀將白菜切斷。然后提升機構(gòu)將白菜運輸?shù)捷斔蜋C構(gòu)上，輸送機構(gòu)再將大白菜運輸?shù)窖b箱裝置，最后把裝滿大白菜的箱子擺放在拖拉機后帶的車廂內(nèi)。如圖1-1所示。
扶莖器主要將大白菜收攏扶正，由一些漸變傾斜桿組成；提升機構(gòu)工作時與地面程傾角，平行的兩條平帶夾緊并將大白菜從地面提升到輸送帶上，提升機構(gòu)位置的固定依靠鎖緊機構(gòu)；輸送帶布置為水平，方便裝箱機構(gòu)裝大白菜。
圖2-1
2.2 收獲機提升運輸裝置簡介
（1)、設(shè)計帶式提升運輸裝置,見圖3-2：
圖2-2
原始數(shù)據(jù)：提升帶速：1.5m/s
平帶帶輪直徑：280mm
工作條件：
連續(xù)單向運轉(zhuǎn)，工作時有輕微振動，使用期限為10年，小批量生產(chǎn)，單班制工作（8小時/天）。運輸速度允許誤差為。
(2)、 傳動方案：
外傳動為V帶傳動
提升運輸為平帶傳動
方案簡圖如圖2-3所示：
圖2-3
(3)、該方案的優(yōu)缺點：
該提升運輸機有輕微振動，由于V帶有緩沖吸振能力，采用V帶傳動能減小振動帶來的影響，并且該工作機屬于小功率、載荷變化不大，可以采用V帶這種簡單的結(jié)構(gòu)，并且價格便宜，標(biāo)準(zhǔn)化程度高，大幅降低了成本。提升部分采用平帶傳動，這是運輸裝置中應(yīng)用最廣泛的一種。V帶由拖拉機上柴油機引出的轉(zhuǎn)速帶動。
總體來講，該傳動方案滿足提升運輸裝置的性能要求，適應(yīng)工作條件、工作可靠，此外還結(jié)構(gòu)簡單、尺寸緊湊以及成本低。
2.3 其他裝置簡介
2.3.1收獲機輸送部分簡介
本設(shè)計選用簡單帶式輸送機為計算實例。該帶式輸送機構(gòu)的結(jié)構(gòu)特征和工作原理是：輸送帶既是承載貨物的構(gòu)件，又是傳遞牽引力的牽引構(gòu)件，依靠輸送帶與滾筒之間的摩擦力平穩(wěn)地進行驅(qū)動。 如圖2-4所示為收獲機帶式輸送機構(gòu)簡圖，輸送帶繞過驅(qū)動滾筒和張緊滾筒。工作時，由內(nèi)燃機通過帶輪裝置使驅(qū)動滾筒轉(zhuǎn)動，依靠驅(qū)動滾筒與輸送帶之間的摩擦力使輸送帶運動，貨物隨輸送帶運送到卸載點。 為了減輕對輸送帶的磨損、提高生產(chǎn)率和便于布置裝、卸載裝置，輸送帶的布置形式為水平輸送。
圖2-4
2.3.2 鎖緊機構(gòu)簡介
由于大白菜收獲機的提升運輸機構(gòu)是可以轉(zhuǎn)動的，它的兩個位置示意圖如圖2-5。其中工作位置1——實現(xiàn)大白菜的收獲的過程，它要求此時要對大白菜提升機構(gòu)有良好的固定作用，不允許其有大的移動和振動，以保證大白菜能順利的往上提升達(dá)到所需的效果；工作位置2——大白菜收獲機在公路上行駛的時候，防止提升機構(gòu)和切削機構(gòu)與地面碰撞而發(fā)生不良影響兩個位置。這就要求一個機構(gòu)能有效的實現(xiàn)這個過程，使它能夠安全和穩(wěn)定的完成上述要求。
圖2-5
為了固定工作位置1（也就是大白菜的收獲位置）時，此時要向右邊推動鎖緊機構(gòu)將提升機構(gòu)牢牢定在工作位置1，保證工作時的可靠性；當(dāng)大白菜收獲機械處于公路行駛的階段時，就要求提升機構(gòu)轉(zhuǎn)到位置2上，此時只要將鎖緊機構(gòu)向左邊拉出，將提升機構(gòu)轉(zhuǎn)到位置2，再將鎖緊機構(gòu)向右邊推動將提升機構(gòu)固定即可。
由上述分析可知：鎖緊機構(gòu)必須可以左右來回運動，且它還要將位置1和位置2固定，這就要求鎖緊機構(gòu)和提升機構(gòu)能很好的貼合，而且接觸面要相對的大一些。且本機械為小型機械，它要求機械的結(jié)構(gòu)簡單，盡量采用手動，而斜楔鎖緊裝置符合這些要求。它的結(jié)構(gòu)如圖2-6所示：
斜塊在軌道中由人做推拉運動，就可以實現(xiàn)提升機構(gòu)所需的位置要求，將鎖緊機構(gòu)和提升機構(gòu)的接觸部位做成斜面能很好的補充因裝配、制造而造成的誤差，從而能夠很好的貼合，增加了工作的穩(wěn)定性。
圖2-6
斜楔鎖緊機構(gòu)雖然有很好的自鎖性,但是農(nóng)業(yè)機械在工作的過程中的振動是比較大的，這樣是有可能因振動而使的自鎖機構(gòu)松動，從而產(chǎn)生不良后果。為了保證大白菜收獲機在工作中的安全性，就要求斜楔機構(gòu)能有很好的防松性能。這里在防松機構(gòu)中利用彈簧的推力將小柱體貼緊斜體，使之不會退出來，達(dá)到防松的目的。
3 提升運輸裝置主要零部件的設(shè)計
3.1 機架的設(shè)計
3.1.1、機架外形
收獲機工作時，提升運輸機構(gòu)與地面成30°角，要提升的高度大約為一米，所以提升運輸機構(gòu)約兩米長，機架相應(yīng)也要兩米長左右?？紤]到長度較長，采用平帶運輸中間部分就可能由于平皮帶具有一定的彈性向內(nèi)凹陷，從而導(dǎo)致中間部分在提升運輸過程中不能很好的夾緊大白菜，甚至出現(xiàn)提升運輸機構(gòu)不能正常工作，所以在中間等距布置三個導(dǎo)輪，保證工作過程中對大白菜的良好夾緊提升運輸。如圖3-1所示：
圖3-1
3.1.2、計算部分
由于初定機架長兩米左右，所以單根平帶至少長四米，查機械設(shè)計手冊有平帶帶長4000mm，4500mm，5000mm。選定4500mm的平帶。
兩端的平帶帶輪直徑根據(jù)大白菜的直徑一般在250mm左右，查機械設(shè)計手冊確定平帶帶輪的直徑為280mm。所以：
208 + 2L = 4500 L = 1810 mm (L為機架長度)
見圖3-2：
圖3-2
3.1.3、機架結(jié)構(gòu)的確定
機架的大致框架采用橫截面為矩形的結(jié)構(gòu)鋼（見圖3-3）焊接在一起形成，底部由網(wǎng)狀連接以增強機架的剛性，頂部敞開，垂直安裝的平帶夾緊大白菜通過機架中間提升運輸?shù)剿璧母叨龋唧w結(jié)構(gòu)詳見裝配圖。
圖3-3
3.2 平帶帶輪的設(shè)計
（1）、尺寸和形狀的確定
根據(jù)大白菜的外形尺寸初定平帶帶輪的直徑為300mm，查機械設(shè)計手冊選定平帶帶輪的直徑為280mm，寬度為198mm， 為防止掉帶，通常在平帶帶輪輪緣表面制成中凸度，根據(jù)平帶帶輪的直徑查機械設(shè)計手冊得平帶帶輪的中凸度為0.8mm，輪輻形式為四孔板輻，四個孔的直徑為40mm，輪轂長為115mm，輪轂孔的直徑為32mm，輪轂內(nèi)外圈之間壁厚為16mm，輪緣厚度為12mm，輪轂與輪輻以及輪輻與輪緣由1：25的錐度過度連接，輪緣邊上有高4mm的凸緣，防止平帶在垂直提升運輸工作過程中沿平帶帶輪軸線方向滑脫，詳見圖紙，示意圖如圖3-4所示：
圖3-4
3.3 平帶的選擇
平帶用來傳遞牽引力和夾緊大白菜，環(huán)繞安裝在軸線與鉛垂線成30°的帶輪上，要求強度高、耐磨耐用、伸長率小和便于安裝修理。帶式提升輸送機使用的輸送帶有橡膠帶、塑料帶、鋼帶、金屬網(wǎng)帶等，最常用的是橡膠帶。輸送帶的張力由帯芯膠布襯墊層承受，帶的強度決定于帶的寬度和帯芯襯墊層數(shù)。同時，為使平帶有足夠的橫向剛度，防止它在支撐帶輪之間向兩側(cè)過分塌陷。應(yīng)根據(jù)帶寬選用一定的襯墊層數(shù)，查《運輸機械設(shè)計選用手冊》得襯墊層數(shù)Z=3，并按下式作輸送帶的強度驗算：
式中 ：——分別為輸送帶實際傳遞的和允許傳遞的最大張力（N);
——輸送帶寬度，cm；
Z——襯墊層數(shù)；
——普通分層帆布帶的抗拉強度，N/層·cm；
n——安全系數(shù)，硫化接頭為8-10。
由于該收獲機提升運輸大白菜時，大白菜是立著被提升到一定高度的，大白菜的高度大約為350mm，而提升運輸大白菜的平帶只需夾緊大白菜的中間偏下部分，之前確定了平帶帶輪的寬度為198mm，而平帶的寬度系列有140mm，160mm，180mm，200mm，因此選用垂直提升運輸帶的寬度為180mm，襯層Z為3并采用硫化接頭，因為硫化接頭在平帶循環(huán)工作工程中不會因為接頭處而損傷大白菜。普通橡膠帶具有成槽性好，伸長率較小，對驅(qū)動滾筒的摩擦系數(shù)較大的優(yōu)點，強度和允許帶速適用于一般通用帶式輸送機，故選用常用的橡膠帶就能滿足要求。通過查相關(guān)資料選擇棉帆布芯輸送帶，型號為CC-56，扯斷強度為56N/（mm層）。每層厚度為1.5mm，每層重量為1.36kg/，參考力拉長率1.5%2%,上下覆蓋膠厚度各為1.5mm。
3.4平帶帶輪軸的設(shè)計
3.4.1 主動軸的設(shè)計
（1）、 選擇軸的材料及熱處理
由于平帶運輸裝置傳遞的功率不大，對其重量和尺寸也無特殊要求故選擇常用材料45鋼,調(diào)質(zhì)處理.力學(xué)性能為：抗拉強度,彎曲疲勞極限，許用扭轉(zhuǎn)應(yīng)力。
（2）、計算轉(zhuǎn)速
因平帶帶輪的直徑為280mm，查相關(guān)資料初定平帶的提升運輸速度為1.25m/s，則軸的轉(zhuǎn)速可根據(jù)一下公式計算得到：
r/min
所以取軸的轉(zhuǎn)速為90 r/min。
（3）、初選軸承
平帶帶輪和機架底部裝配選用接觸角為12°的圓錐滾子軸承（見圖3-5a），因底部安裝的軸承要承受平帶帶輪的重力以及其他工作部件的重力，其中主要是平帶帶輪的重量，力不是很大，查相關(guān)手冊得知接觸角為12°可以滿足工作要求；平帶帶輪和機架頂部裝配選用的軸承為深溝球軸承(見圖3-5b)，因頂部的軸承只需承受軸的徑向力。
根據(jù)軸承確定各軸安裝軸承的直徑為:
圓錐滾子軸承和深溝球軸承的直徑都為30mm。查設(shè)計手冊得知：圓錐滾子軸承的標(biāo)準(zhǔn)號為：GB297-84,型號為：2007106E；深溝球軸承的標(biāo)準(zhǔn)號為：GB276-89，型號為：60106.
圖3-5a
圖3-5b
（4）、軸外形機尺寸的確定
軸直徑的確定
初估軸徑后,就可按軸上零件的安裝順序,從底端開始確定直徑.最底端軸段1安裝軸承2007106E,故該段直徑為30mm。中間軸段2安裝平帶帶輪，設(shè)計為32mm。與機架頂部裝配的軸段3安裝軸承60106,故該段直徑也為30mm。最上面留出一段直徑為28mm的軸段4裝V帶帶輪。。
各軸段長度的確定
軸段1的長度大致為軸承2007106E的寬度，取18mm長。軸段2為機架底部到頂端之間的距離，取210mm。軸段3的長度按軸承60106的寬度確定，取14mm。軸段4伸出機架安裝V帶帶輪，考慮到大白菜高約300mm，根部露出機架底面約30mm，夾在機架中間240mm，菜葉部分高出機架頂面約長30mm，所以把V帶輪設(shè)計安裝在高出機架頂面60mm的地方，故軸段4長100mm。V帶輪安裝在軸端一段直徑為20mm長19mm的軸段上，這段軸上還開有一6x16的鍵槽。軸端中心鉆有一M6x11深13mm的孔，用于安裝帶有M6螺紋的軸端擋圈，使V帶輪軸向定位。
軸上零件的周向及軸向固定
為了使安裝方便，平帶帶輪與軸選用間隙配合H6/g5。與軸承內(nèi)圈配合軸徑選用r5，平帶帶輪與軸采用兩個A型普通平鍵聯(lián)接，為1045 GB1096。平帶帶輪的輪轂部分寬115mm，要固定在中空高度為210mm的機架的中間，在輪轂的每一端安裝兩個半圓形的擋圈，防止平帶帶輪的軸向竄動。
軸上倒角與圓角
為保證軸承內(nèi)圈端面緊靠定位軸肩的端面，根據(jù)軸承手冊的推薦，取軸肩圓角半徑為0.5mm。。根據(jù)標(biāo)準(zhǔn)GB6403.4-1986，軸的左右端倒角均為145。
軸的結(jié)構(gòu)圖見圖3-6：
圖3-6
3.4.2 從動軸的設(shè)計
從動軸在受力等各方面工作條件比主動軸要好，所以把從動軸設(shè)計為取主動軸的軸段1、2和3。主動軸能滿足工作要求，從動軸如此設(shè)計也能滿足工作要求。從動軸結(jié)構(gòu)圖見圖3-7所示：
圖3-7
3.5 端蓋
平帶帶輪上的圓錐滾子軸承和深溝球軸承內(nèi)圈可以靠軸肩和軸套定位，而外圈要用端蓋定位，示意圖如圖3-8所示：
圖3-8
端蓋圓周任一直徑上鉆有兩個6的光孔，軸承座上鉆有M6的螺紋，通過M6的螺栓把端蓋連接在軸承座上，端蓋下面部分套入軸孔接觸到軸承外圈，從而達(dá)到軸承的軸向定位。端蓋中間比兩邊要凹下一點是為了減少加工面的大小，改善零件的加工工藝性。
3.6 支承軸的設(shè)計
1）：支承軸 在機架中間均布著三根支承軸，因為支承軸受力不大，選用16的軸，長320mm，直接設(shè)計成一根螺栓，頭部螺紋長50mm，詳見圖紙部分。
2）：軸套 與支承軸間隙配合，保護套筒的內(nèi)圈精度。因套筒的內(nèi)圈加工較支承軸難，所示特在套筒和支承軸間加一軸套，內(nèi)徑16mm，長200mm，壁厚2mm，軸套與套筒采取過盈配合，工作時，軸套和套筒一起繞支承軸轉(zhuǎn)動。
3）：套筒 因支承軸較細(xì)，所以在支承軸外套一內(nèi)徑20mm，長200mm，壁厚15mm的套筒，以增加平帶工作的穩(wěn)定性，裝配關(guān)系如上所述。
4）：螺母和墊圈 選用標(biāo)準(zhǔn)的M16螺母和與M16螺母想配合的墊圈，因都已標(biāo)準(zhǔn)化，所以不詳述。
4 結(jié)論
4.1 主要結(jié)論
本課題在進行了大量調(diào)查和文獻(xiàn)檢索的基礎(chǔ)上，對大白菜收獲機帶式輸送機構(gòu)以及其張緊系統(tǒng)進行了一定的理論分析，了解了目前國內(nèi)帶輸送機張緊裝置現(xiàn)狀以及其使用情況，仔細(xì)分析了存在的問題，對該裝置各個部分的元件進行了選型、設(shè)計，并繪制了CAD圖紙。在總個設(shè)計中，得到了以下主要結(jié)論：
（1）在分析了帶式輸送機構(gòu)的原理基礎(chǔ)上，結(jié)合本課題所研究的帶式輸送機構(gòu)系統(tǒng)，為帶式輸送機構(gòu)的設(shè)計選型提供了依據(jù)，具有一定的參考意義。
（2）在分析研究現(xiàn)有螺旋張緊裝置使用情況的前提下，提出了螺旋張緊裝置的總體設(shè)計方案，該裝置可實現(xiàn)對輸送帶張力的調(diào)節(jié)。
4.2 問題與展望
本論文做的是一個研究性設(shè)計，研制開發(fā)新產(chǎn)品，雖然研制出一套螺旋張緊裝置系統(tǒng)，所需的功能也能完成，但要做成一個產(chǎn)品還需繼續(xù)完善，許多工作有待于進一步改進。例如，由于試驗條件的限制，沒有對螺旋張緊的各個部分作計算機模擬仿真實驗，只停留在理論的基礎(chǔ)上。
張緊技術(shù)是帶式輸送機構(gòu)的關(guān)鍵技術(shù)，它可以大大提高輸送機運行的可靠性。隨著農(nóng)業(yè)收獲機向大型化和高速化方向發(fā)展，本設(shè)計為收獲機帶式輸送機構(gòu)張緊技術(shù)的發(fā)展提供了一定的理論和實踐依據(jù)。
5 設(shè)計心得
畢業(yè)設(shè)計是四年學(xué)習(xí)當(dāng)中一個重要環(huán)節(jié)，通過了這個學(xué)期的畢業(yè)設(shè)計，使我從各個方面都受到了機械設(shè)計的訓(xùn)練，對機械的有關(guān)各個零部件有機的結(jié)合在一起得到了深刻的認(rèn)識。
由于在設(shè)計方面我們沒有經(jīng)驗，在設(shè)計中難免會出現(xiàn)這樣那樣的問題，如：在選擇計算標(biāo)準(zhǔn)件是可能會出現(xiàn)誤差，如果是聯(lián)系緊密或者循序漸進的計算誤差會更大，在查表和計算上精度不夠準(zhǔn)確.
在畢業(yè)設(shè)計的過程中，培養(yǎng)了我綜合應(yīng)用機械設(shè)計課程及其他課程的理論知識和應(yīng)用生產(chǎn)實際知識解決工程實際問題的能力，在設(shè)計的過程中還培養(yǎng)出了我們的團隊精神，大家共同解決了許多個人無法解決的問題，在這些過程中我們深刻地認(rèn)識到了自己在知識的理解和接受應(yīng)用方面的不足，在今后的學(xué)習(xí)過程中我們會更加努力和團結(jié)。
由于本次畢業(yè)設(shè)計是分部分完成的，自己獨立設(shè)計的東西不多，但在通過這次設(shè)計之后，我想會對以后自己獨立設(shè)計打下一個良好的基礎(chǔ)。
參考文獻(xiàn)
[1] 濮良貴，紀(jì)名剛。機械設(shè)計，第八版。北京：高等教育出版社，2006.
[2] 譚建榮，張樹有。圖學(xué)基礎(chǔ)教程。北京：高等教育出版社，2004.
[3] 劉鴻文。材料力學(xué)，第四版。北京：高等教育出版社，2004.
[4] 曾志新，呂明。機械制造技術(shù)基礎(chǔ)。武漢：武漢理工大學(xué)出版社，2001.
[5] 實用機械設(shè)計手冊 （上冊）。北京：機械工業(yè)出版社，1994.
[6] 運輸機械設(shè)計選用手冊 （上冊）。北京：化學(xué)工業(yè)出版社，2005.
致 謝
這次畢業(yè)設(shè)計是在肖麗萍老師的精心指導(dǎo)下完成的，在整個學(xué)習(xí)和做論文的過程中，肖老師對我們悉心指導(dǎo)和嚴(yán)格要求，為我們創(chuàng)造了良好的學(xué)習(xí)氛圍；她嚴(yán)謹(jǐn)?shù)闹螌W(xué)態(tài)度、高尚的敬業(yè)精神和淵博的學(xué)識，給我留下了深刻的印象，對我產(chǎn)生了巨大的影響，使我不僅掌握了更多的理論知識，而且在分析問題、解決問題的能力上有了很大的提高。
在此，我特向肖老師表示崇高的敬意和衷心的感謝！在整個論文期間，我還得到了許多同學(xué)的幫助，他們給了我很多建設(shè)性的建議，讓我受益非淺。特向他們表示誠摯的謝意！
最后，我要感謝大學(xué)的所有老師，是他們無私地教導(dǎo)我，使我掌握了機制專業(yè)的基礎(chǔ)知識，為這次的畢業(yè)設(shè)計和我以后的工作奠定了基礎(chǔ)。感謝他們多年的教育、關(guān)心、支持和鼓勵！謝謝！
李傳龍
2009年5月
編 號
江西農(nóng)業(yè)大學(xué) 工學(xué)院
畢業(yè)設(shè)計材料
題 目
大白菜收獲機機械部分設(shè)計
——提升運輸機構(gòu)的設(shè)計
專 業(yè)
學(xué)生姓名
材 料 目 錄
序號
附 件 名 稱
數(shù)量
備注
1
畢業(yè)設(shè)計說明書
1
2
CAD圖紙
6
3
設(shè)計任務(wù)書
1
二〇〇九年五月
2950 Niles Road, StJosepli _ 49085-9659, USA 269.429-0300 fax 26S.4293SS2 hc|#asabe.org
www.asabe.org
An ASABE Meeting Presentation Paper Number: 084469
7760 Cotton Picker
Jason D. Wattonville
John Deere Des Moines Works, Ankeny, Iowa, USA
Written for presentation at the 2008 ASABE Annual International Meeting Sponsored by ASABE Rhode Island Convention Center Providence, Rhode Island June 29 - July 2，2008
Abstract. The John Deere 7760 Cotton Picker, with on-board module building technology, offers customers the next revolution to cotton harvesting machinery. The 7760 breaks through the productivity barrier by way of virtual non-stop harvest. The 7760 can harvest non-stop or continuously pick while forming, wrapping, ejecting and carrying a round module. Building round modules on-board the machine eliminates most field support equipment and the additional labor and costs associated with it. Wrapping the round modules in waterproof plastic wrap provides better protection to preserve cotton fiber and cotton seed quality while containing the cotton in the module so minimal cotton is lost during handling and transport. Some other key features of the 7760 include a Tier III emissions compliant 13.5L engine (500 hp), Pro Drive? powershift transmission, CAN BUS electronics, updated operator station, and improved serviceability and diagnostics.
Keywords. Agricultural Equipment, Cotton, Cotton Harvesters, Farm Machinery, Harvesting Machinery
The authors are solely responsible for the content of this technical presentation. The technical presentation does not necessarily reflect the official position of the American Society of Agricultural and Biological Engineers (ASABE), and its printing and distribution does not constitute an endorsement of views which may be expressed. Technical presentations are not subject to the formal peer review process by ASABE editorial committees; therefore, they are not to be presented as refereed publications. Citation of this work should state that it is ftorn an ASABE meeting paper. EXAMPLE: Author's Last Name, Initials. 2008. Title of Presentation. ASABE Paper No. 08-—. St. Joseph, Mich.: ASABE. For information about securing permission to reprint or reproduce a technical presentation, please contact ASABE at
iutter@asabe.org or 269-429-0300 (2950 Niles Road, St. Joseph, Ml 49085-9659 USA).
7760 Cotton Picker
Introduction
Feedback from a worldwide customer base, representing all segments of the cotton industry, expressed the need to enhance and improve the entire cotton production chain — a chain that includes harvesting, handling, transporting and ginning seed cotton. The overall customer request was to "help us- reduce our labor, reduce our assets, increase our flexibility and help us preserve fiber quality." To provide a solution of increased efficiency and profitability, we needed a systematic paradigm shift (see Figure 1) which involved 3 groups of constituents: farmers, transporters and ginners. Input from those constituents helped define the requirements for a new generation cotton harvester, the John Deere 7760 Cotton Picker. Equipped with built-in module-building technology, the 7760 is a revolutionary cotton-harvesting machine which streamlines the stages of cotton production, from the initial picking of the plant to the completion of the lint bale.
Figure 1, 7760 Harvesting System Approach
project Description
FigCire 2. Current Basket Picker Harvesting Process
Typically, every 6 row cotton picker requires four pieces of support equipment along with labor to operate that equipment (see Figure 2). The labor, cost and management challenges associated with supporting cotton harvest is one of the primary drivers and inspiration for the 7760 and producing round modules on-board the harvester.
Development of producing modules on-board cotton pickers began as far back at the 80’s.
John Deere began experimenting with various packaging techniques to determine optimum size and shape for building cotton modules on-board the cotton harvester.
Since the industry had standardized on conventional modules, early experiments involved partitioning a conventional module builder to evaluate partial size modules. The major issues to be addressed with this concept were: 1) the lack of module integrity; 2) the low package (module) density; 3) the requirement of the vehicle to stop for module unloading. These issues would have contributed to higher transportation costs, lower ginning efficiency and unimproved or reduced harvesting productivity. Additionally, the smaller “mini” modules did not offer improvements in handling, transportation or improvements to fiber preservation. Since these issues resulted in not meeting the requirements that our customers were asking for, the focus was turned to an alternate package type, the round module (bale). The first advantage we saw in the round shape was that it sheds water naturally and lends itself to being covered automatically. A waterproof protective covering completely around the circumference of the round module helps preserve the fiber and reduce seed cotton losses incurred by handling and/or transportation.
Additionally, the round module enables the 7760 to harvest non-stop resulting in a dramatic machine productivity increase of 20% or more. The 7760 eliminates the time spent unloading, waiting for boll buggies, or driving back and forth to a module builder as round modules can be wrapped, ejected, carried and dropped at the turn row without ever needing to stop the machine. The non-stop harvesting function of the 7760 Picker trims approximately five days off of the typical four-week harvest.
The vision for this program is as follows:
? Reduce labor requirements
? Improve asset utilization
? Increase productivity
? Lower harvesting costs
? Preserve cotton fiber and reduce losses
? Increase handling and transportation option
The performance requirements for this vehicle are outlined in Table 1. In many cases, our requirements were based against the current 9996 cotton picker since it has and continues to be the market leader in the 6 row class of cotton pickers.
Table 1: 7760 Performance Requirements
Model
7760
Productivity increase over 9996
20%
Ability to non-stop harvest (up to 4 bale/acre yields at 4.2 mph)
Yes
Fluid capacity
12 hrs Continuous
Improved shift-ability
Yes
Locked wheel during powered brake turn
Yes
Field transport height
Equivalent to 9996
Shipping height
Equivalent to 9996
Flotation
Equal or greater than 9996
Tractive efficiency
Equal or greater than 9996
Tractive effort
Equal or greater than 9996
Standard front dual drive tires
Yes
Option single front drive tires
No
Improved maneuverability over 9996
Yes
Tier III emissions compliant
? Yes
Accumulator Round Module Builder j Wrap Mechanism
Figure 3. Machine Cut-Away
Theory of Operation
'i he following section describes the theory of operation of the round module building process on-board the 7760. Please refer to Figure 3 in this section.
Accumulator
Accumulator technology and monitoring provides an 8.5 mA3 (300 ftA3) chamber or buffer that temporarily stores 1000-1200 lb seed cotton during the wrap and eject process. This buffer is what allows the machine to harvest non-stop.
The accumulator working in conjunction with a double reverse flighted auger ensures an even and uniform flow of cotton is delivered to the round module builder resulting in consistent cylindrical formed round modules in all conditions.
Mounted to the top of the accumulator is the lid extension and hood. It contains perforated screens and fingergrates that provide a means to separate trash from the cotton and also provides self-raising and lowering of the ducts.
Sensors monitor the level of cotton within the accumulator to start and stop the feeding process f「om the accumulator into the round module builder.
Feed rolls convey cotton from the accumulator to the feeder belt. The feed roll metering system is patented technology.
Feeder
Cotton received from the accumulator feed rolls is transported via a rubber belt and compressed between this belt and a laydown roller resulting in a uniform ribbon (or mat) of cotton presented to the entrance or throat of the round module builder. The feeder is also patented technology developed jointly between John Deere and PA Consulting.
Round Module Builder
The round module builder has the capability to automatically build, wrap, eject (on demand), and drop uniform and consistent modules without stopping the machine. The round module builder is powered by an electronic controlled hydrostatic system that operates in conjunction with the feeder system.
The round modules can be variable in size up to the target diameter of 2439 mm (90，’）and a width of 2388mm (94，，）and will weigh approximately 5000 lbs depending on moisture content of the cotton. This size of module will allow unloading on one end of the field in all but extreme operating conditions (high yields and long rows).
Portioned Wrap & Wrap System
The round module covering consists of an industry first portioned wrap (eliminates a cutting mechanism) made of a non-contaminating LLDPE material. LLDPE, is the same material used for lint bale covers today and is recyclable. The wrap will provide package integrity, puncture resistance, and full surface coverage with an edge-wrap feature (CoverEdge?) to provide weather resistant protection for the seed cotton package. Wrap will be provided in rolls that weigh 100 kg (220 lbs) and contain 22 portions.
The wrap mechanism will have the capability to separate the portioned wrap as it is applied to the round module during the wrapping process. Fully loaded, the machine can carry 110 wraps (five rolls). One roll is positioned in the wrap mechanism with four .additional rolls in the magazine. This provides more than enough wraps to complete a 12 hour harvest day.
Handler
The handler carries a round module to the desired field staging location. It also provides a means to lower the round module builder down to an acceptable shipping and field transport height. The rear gate of the round module builder rests in slots located on the handler which guides the builder into this configuration. Figure 4 shows the machine in field transport configuration.
Figure 4. Field transport position
ltAuto" Mode Module Building
"Auto" mode enables the machine via electronics, hydraulics, software and sensors to automatically control the building of each round module. “Auto” mode is engaged by pushing one button on the hydro handle alleviating the complexity of module making.
During the automated round module building process, the comerpost and armrest displays provide clear and concise feedback to the operator indicating exactly where the machine is at in executing the process.
The round module builder or baler does not run continuous, but rather cycles on and off as needed. The cycle is controlled by 2 sets of infrared through-beam sensors. The upper sensors sense when the accumulator is full, initiating the module building cycle to start. The cycle continues until the lower set of sensors are activated stopping the cycle. This repeats itself until the round module reaches its maximum diameter of 90，，. When it reaches 90”，the cotton flowing from the accumulator is stopped and the wrap cycle is automatically initiated wrapping the round module. After the round module is wrapped, the operator interface asks the operator to eject. Confirmation is required to eject the round module out onto the handler. Cotton continues to pour into the accumulator during the wrap and eject cycle. After the round module has been ejected and the gate closes, the system is ready to repeat itself.
Key Features
Non-Stop Harvest
“Auto" mode, described in the previous section, enables the machine to automatically control the building of each round module allowing the picker to harvest continuously while forming, wrapping, ejecting and unloading round modules from the machine. Eliminating stops, for any reason, keeps the picker harvesting cotton.
Operator Station
The 7760 features a newly designed cab for a much improved operator's environment. New operator interfaces have been added that include a CommandCenter display mounted to the revised and updated armrest (see Figures 5 and 6). The cab layout has been revised to provide for an LCD based Cornerpost Display, updated armrest control locations, Harvest Doc Cotton ready, and overhead console revisions. With the addition of the CommandCenter display, information such as internal alarms, diagnostic trouble codes, diagnostic addresses, calibrations, mode management setup screens, set point adjust, and text displayed messages are available to the operator. The addition of the LCD based Cornerpost Display Unit provides for a dedicated round module builder display (see Figure 6), as well as a display for general harvest monitoring. Harvest warning indicators have been added for complete operator warning annunciation.
Figure 5. The all-new CommandCenter display and CommandTouch console
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Electronic Unit Synchronization
Currently, picking unit synchronization to ground speed is done via a mechanical link between the ground drive and unit drive hydrostatic pumps. Each machine requires adjustment as part of the manufacturing process. The 7760 program has developed the electronic unit speed synchronization system. This technology eliminates the synchronization adjustment in manufacturing and delivers synchronized unit speed at picking speeds up to 4.2 mph. The improved range of synchronization improves the picking efficiency of the machine. System calibrations provide for precise and accurate control of the picking unit speeds for the entire harvest range.
ProDrive? Automatic Shift Transmission
The 7760 also has a new electronic controlled 2-speed powershift transmission with automatic shifting and independent hydraulic wet disc brake design with an integrated spring applied, hydraulic released park brake. Increased tractive effort and higher loads will be carried through a high capacity four pinion differential with hydraulically actuated differential lock to more effectively and reliably transfer the power to the ground in adverse as well as normal conditions.
Electronic Controlled Variable Speed Hydrostatic Ground Drive
ProDrive? Automatic-ShiftTransmission (AST)
? Picking Mode 6.8 kph (4.2 mph)
? Scrapping Mode 8.1 kph (5.0 mph)
? Field Transport Mode 14.5 kph (9.0 mph)
? Road Transport Mode 27.4 kph (17.0 mph)
Power Module
The heart within the power module is a tier III emission certified 13.5L John Deere PowerTechPlus? engine rated at 373 kW (500 HP) @ 2100 RPM. Coupled to this powerplant is a direct drive pump drive gearbox which provides efficient transfer of power to the hydrostatic, hydraulic systems and cotton fans.
Walk-under Mainframe
The new mainframe design allows walk-under clearance into the power-module area to improve access into the engine compartment for daily service and maintenance.
Air System
In order to meet the increased cotton conveying demands due to increasing ground speed to 4.2 mph, twin high efficiency fans deliver improved air flow rates and consume less power.
Mechanical Rear Drive Axle
The on-board cotton handling/moduling system added nearly 20,000 lbs of weight to the rear axle compared to our current 9996 cotton harvester.
A new rear axle and tire size (see Figure 7) were developed to address higher vehicle weights (without increasing ground compaction), increased tractive effort requirements and increased maneuverability requirements.
Figure 7. Mechanical rear axle
By converting to larger radial constructed rear tires, ground compaction under the rear tires remains comparable to the 9996. The static loaded rolling radius increased 30% over the 9996.
The new rear axle is powered 100% of the time by an electronically controlled hydrostatic system. This system works in conjunction with the front axle hydrostatic system to provide increased rim pull while maintaining current transport speed. This translates into a machine that is better at climbing hills and is less prone to getting stuck in muddy conditions.
Improvements to turning radius over the 9996 cotton picker, in light of a 20% increase in vehicle wheelbase, are possible due to a 55-degree steer angle, a 34% increase in steer angle over the 9996. This results in improved vehicle maneuverability over the 9996 by actually reducing the vehicle turning radius by over 36%. This reduction allows the machine to turn back on the adjacent unpicked rows without requiring the use of power hydraulic brakes or making a three point turn, resulting in less structural stress, less power, and less time to make the turn.
Spec Comparison
Rear axle weight comparisons
9996= 18,000 lbs 7760 = 38,000 lbs 111% increase in rear axle weight Tread setting options
Same for both a 9996 and 7760 - 30,32,36,38 & 40 in Oscillation comparison 9996 = 8.3 deg 7760 = 9.0 deg
8.4% increase oscillation angle Wheel base comparison
9996= 141" (3.58m)
7760 = 170" (4.32m)
20.6% increase in wheel base Steer angle comparison 9996 = 41 deg 7760 = 55 deg
34.1 % increase in steer angle
Turning radius comparison (6 row heads require tighter turning radius to turn back on adjacent 6 rows)
9996 = 236” (5.99m)
7760 = 150”（3.81m)
36.4% reduction in turning radius
Ground compaction
Within 2-3 psi of 9996
Round Module Handling
Figure 9. Round Module Handler CM1100
Figure 8. Staging Round Modules
It was already mentioned that the round shape sheds water and the plastic wrap protects the fiber. Some other notable advantages of the round modules include water protection and reduced waste during moving. Notice how the cover-edge on the round module keeps the water away from the fiber (see Figure 10) when exposed to ponding rainfall. And when the round modules are moved, there’s typically less waste as well. Typical waste or cotton left behind in the field and gin yard when moving conventional modules (see Figure 11).
Once the cotton is harvested, the round modules are easily staged for conventional module truck pick-up (see Figure 8), moved to high ground if necessary, or loaded for transport. The Frontier Round Module Handler CM 1100，coupled to an 8000 series John Deere tractor, provides an effective solution to move, stage or load round modules (see Figure 9) and also provides the flexibility to do these operations when convenient and when circumstances and manpower allow.
11
Table 2: Machine Specifications
Figure 10. Round Modules in Standing Water
Figure 11. Waste from Conventional Modules
Module Transporting
The round modules provide additional flexibility for transporting seed cotton to the gin as either a traditional module truck (see Figure 12), with the chain bed modified slightly, or a standard flatbed trailer can be used (see Figure 13).
Figure 12. Conventional Module Truck Figure 13. Flatbed Trailers
Ginning
We’ve invested a tremendous amount of engineering time and energy to make sure that the round modules are uniform. Uniform in size, density and moisture. This uniformity has proven to be very beneficial to the ginning process. Ginning experts that hav