櫻桃番茄分級傳輸機(jī)構(gòu)設(shè)計【氣動水果分級傳輸裝置】
櫻桃番茄分級傳輸機(jī)構(gòu)設(shè)計【氣動水果分級傳輸裝置】,氣動水果分級傳輸裝置,櫻桃番茄分級傳輸機(jī)構(gòu)設(shè)計【氣動水果分級傳輸裝置】,櫻桃,番茄,分級,傳輸,機(jī)構(gòu),設(shè)計,氣動,水果,生果,瓜果,裝置
任務(wù)書
設(shè)計(論文)
課題名稱
櫻桃番茄分級傳輸機(jī)構(gòu)設(shè)計
學(xué)生姓名
院(系)
專 業(yè)
指導(dǎo)教師
職 稱
學(xué) 歷
畢業(yè)設(shè)計(論文)要求:熟練掌握AutoCAD,Pro/E等繪圖軟件,對機(jī)械原理,機(jī)械設(shè)計有較深入的理解和認(rèn)識。
畢業(yè)設(shè)計(論文)內(nèi)容與技術(shù)參數(shù):
1. 分揀速度5個/秒,鏈傳動速度V=0.25m/s。
2. 系統(tǒng)高度小于2m,總長小于2.5m。
3. 功率p=0.5kw。
畢業(yè)設(shè)計(論文)工作計劃:
1.設(shè)計前期階段,
根據(jù)原理大致的估計設(shè)計的大致模型,以至構(gòu)思簡單的設(shè)計思路。對櫻桃番茄的一些物理參數(shù),形狀大小進(jìn)行提取
2.初模型設(shè)計階段,畫出模型的大致草圖,并最終確定設(shè)計思路。
3.計算和階段, 此階段的工作任務(wù)是計算出零件的尺寸以及機(jī)構(gòu)的安裝尺寸。
4.畫零件圖和裝配圖階段,根據(jù)第三階段計算出的數(shù)據(jù)畫出零件圖和裝配圖,并將其轉(zhuǎn)換成三維立體圖像以便更準(zhǔn)確直觀的分析和改進(jìn)。
5優(yōu)化并編寫設(shè)計說明書階段。
接受任務(wù)日期 2009 年 3 月 20日 要求完成日期 2009年5月15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
學(xué)校代碼:
序 號:
設(shè) 計
題目: 櫻桃番茄分級傳輸機(jī)構(gòu)設(shè)計
學(xué) 院:
姓 名:
學(xué) 號:
專 業(yè):
年 級:
指導(dǎo)教師:
二OO九年 五 月 十 日
櫻桃番茄分級傳輸機(jī)構(gòu)設(shè)計
摘要
隨著科學(xué)技術(shù)的飛速發(fā)展,各行各業(yè)都已不同程度的步入了機(jī)械化時代。而傳統(tǒng)的人操縱機(jī)械已逐步被淘汰,取而代之的是科技含量高的自動化,機(jī)電一體化。水果自動分揀系統(tǒng)是一中集機(jī)械傳動,圖像處理,PLC電路控制的機(jī)電結(jié)合的現(xiàn)代化設(shè)備。目前,對于一些體積小重量輕的水果一般采用氣動分揀。它主要可分為水果圖象采集段和水果分級段,水果在攝像室內(nèi)進(jìn)行圖象采集后,圖象采集段輸出信號給水果分級段,水果分級段的控制件根據(jù)信號做出相應(yīng)的動作控制氣泵噴氣將符合分級標(biāo)準(zhǔn)的水果,吹離輸送裝置并完成分級。由于氣動機(jī)構(gòu)的氣體壓力可調(diào)節(jié),分級操作簡單準(zhǔn)確成本低,便于推廣和使用,且有效減小了機(jī)械力對水果的損傷。因此,它必將取代傳統(tǒng)的水果分揀系統(tǒng)。
關(guān)鍵字
自動化
圖像處理
氣動
分揀
Abstract
With the rapid development of science and technology, have varying degrees of all walks of life entered the era of mechanization. Whereas the traditional manipulation of machinery has gradually been eliminated, replaced by high-tech automation, electrical and mechanical integration. Automatic fruit sorting system is a set of mechanical transmission, image processing, PLC's mechanical and electrical circuit control combined with the modern equipment. At present, some small and light weight of the fruit generally use pneumatic sorting. It can be divided into image collecting fruits and fruit classification paragraph, fruit indoors in camera after the image acquisition, image acquisition above the output signal to the above classification of fruit, fruit pieces graded in accordance with paragraph control signal to the corresponding action to control air jet would be consistent with the classification standards of fruit, blown off and complete the grading conveyor. Institutions as a result of gas pressure pneumatic adjustable, accurate classification is simple and low cost, ease of dissemination and use of, and effectively reduces mechanical damage to fruit. Therefore, it will replace the traditional fruit sorting system.
Keyword
Automation
Image Processing
Pneumatic
Sorting
II
櫻桃番茄分級傳輸機(jī)構(gòu)設(shè)計
目錄
摘要 I
Abstract II
第一章 緒論 1
1.1氣動水果分級傳輸裝置原理簡介 1
1.2傳輸分級機(jī)構(gòu)工作原理 2
1.3設(shè)計安排 2
第二章 主要技術(shù)參數(shù)和電機(jī)選擇 4
2.1主要技術(shù)參數(shù)和電機(jī)選擇 4
2.2櫻桃番茄主要參數(shù) 5
第三章 傳動系統(tǒng)設(shè)計 6
3.1鏈條和鏈輪的設(shè)計 6
3.1.1鏈輪的設(shè)計 6
3.1.2鏈條的設(shè)計計算 8
3.2滾子設(shè)計 10
3.3 軸承和軸承座的設(shè)計 11
3.3.1 軸和軸承的安裝方式 12
3.4同步帶和同步帶輪設(shè)計 13
3.4.1同步帶選擇 13
3.4.2同步帶帶輪設(shè)計計算 14
3.5軸的設(shè)計 15
3.5.1主動軸設(shè)計及校核 15
3.5.2從動軸設(shè)計 16
第四章 安裝結(jié)構(gòu)設(shè)計計算 17
4.1機(jī)架設(shè)計 17
4.1.1機(jī)架材料選擇 17
4.1.2 機(jī)架連接方式 18
總結(jié) 19
參考文獻(xiàn) 20
第一章 緒論
1.1氣動水果分級傳輸裝置原理簡介
帶有氣動分級機(jī)構(gòu)的水果輸送裝置,該裝置包括基架、固定在基架上的驅(qū)動機(jī)構(gòu)和水果輸送機(jī)構(gòu),水果輸送機(jī)構(gòu)分為水果圖象采集段和水果分級段,水果在攝像室內(nèi)進(jìn)行圖象采集后,圖象采集段輸出信號給水果分級段,水果分級段內(nèi)基架的一側(cè)邊,固設(shè)有一個以上氣動機(jī)構(gòu),它主要由儲氣罐和控制件組成,在儲氣罐端部開設(shè)氣體噴嘴,由控制件控制其動作,該控制件的輸入與攝像室水果圖象采集的分級輸出信號相連,氣動機(jī)構(gòu)接收信號后產(chǎn)生噴氣動作,將符合分級標(biāo)準(zhǔn)的水果,吹離輸送裝置并完成分級。本氣動機(jī)構(gòu)的氣體壓力可調(diào)節(jié),分級操作簡單準(zhǔn)確,滾子的模具制造簡單、成本低,便于推廣和使用,且有效減小了機(jī)械力對水果的損傷。原理如圖:
1.2傳輸分級機(jī)構(gòu)工作原理
本設(shè)計的設(shè)計目的是設(shè)計一種機(jī)構(gòu)對櫻桃番茄按大小形狀同進(jìn)行分級,根據(jù)設(shè)計要求將櫻桃番茄分成三個級別。此機(jī)構(gòu)是通過氣動進(jìn)行分級。在此機(jī)構(gòu)中主要由基架,定制的雙側(cè)套筒傳動鏈,雙錐式滾子,雙側(cè)鏈輪,軸承,軸承套,同步帶和同步帶輪以及動力裝置電動機(jī)。
本裝置是水平放置的橫式傳輸機(jī)構(gòu),首先櫻桃番茄由入料可均勻的進(jìn)入界以雙側(cè)鏈的錐式滾子上,在入口處裝有毛刷擋板以確保櫻桃番茄是逐個無重疊的在滾子上傳輸。鏈條以恒定的轉(zhuǎn)速水平進(jìn)行傳動。動力裝置通過同步帶驅(qū)動鏈輪的主動軸驅(qū)使套筒鏈勻速轉(zhuǎn)動,櫻桃番茄油滾子傳輸至第一級出口處,此時空壓機(jī)和氣泵根據(jù)要求進(jìn)行噴氣使櫻桃番茄脫離滾子以達(dá)到分級的要求。下一等級的櫻桃番茄傳輸至第二級出口時以同樣的原理進(jìn)行分級。剩下的第三級隨著滾子直接進(jìn)入位于機(jī)構(gòu)末端的出口。整個過程中機(jī)構(gòu)平穩(wěn)的精確的根據(jù)要求將櫻桃番茄分成了三個等級。進(jìn)而達(dá)到設(shè)計目的。
1.3設(shè)計安排
在做本設(shè)計前,我將我的設(shè)計工作安排劃分為五個階段。
第一階段,設(shè)計前期階段。
在此階段的主要任務(wù)是,首先要清楚此設(shè)計的設(shè)計目的和任務(wù)以及整體裝置的工作原理。根據(jù)原理大致的估計設(shè)計的大致模型,以至構(gòu)思簡單的設(shè)計思路。其次是了解掌握必要的市場動向,借鑒類似前沿的產(chǎn)品以便產(chǎn)生必要的設(shè)計靈感,使設(shè)計達(dá)到最優(yōu)化。第三,因?yàn)樽龃藱C(jī)構(gòu)是用來對櫻桃番茄進(jìn)行分級的,所以必須對櫻桃番茄的一些物理參數(shù),形狀大小進(jìn)行提取。這也是第一階段的重點(diǎn)工作。
第二階段,初模型設(shè)計階段。
此階段的主要工作任務(wù)是在第一階段的前提下大致的構(gòu)思出機(jī)構(gòu)的模型以及機(jī)構(gòu)的大體組成部分。畫出模型的大致草圖,并最終確定設(shè)計思路。
第三階段,計算和必要零件選擇階段。
此階段的工作任務(wù)是計算出零件的尺寸以及機(jī)構(gòu)的安裝尺寸,并根據(jù)需要確定哪些零件是要定制件哪些是采用標(biāo)準(zhǔn)件。另外,通過計算從機(jī)械手冊選擇出標(biāo)準(zhǔn)件。
第四階段,畫零件圖和裝配圖階段。
此階段的主要任務(wù)是根據(jù)第三階段計算出的數(shù)據(jù)畫出零件圖和裝配圖,并將其轉(zhuǎn)換成三維立體圖像以便更準(zhǔn)確直觀的分析和改進(jìn)。
第五階段,優(yōu)化并編寫設(shè)計說明書階段。
在此階段可以參照二維和三維模型對設(shè)計的不合理以及有待進(jìn)一步優(yōu)化的地方進(jìn)行改進(jìn)和優(yōu)化。在改進(jìn)優(yōu)化確認(rèn)無誤后編寫出設(shè)計說明書。
第二章 主要技術(shù)參數(shù)和電機(jī)選擇
2.1主要技術(shù)參數(shù)和電機(jī)選擇
傳輸鏈輪傳輸速率v(m/s)
0.25
機(jī)架長度L(mm)
2210
整體高度H(mm)
1850
鏈輪傳輸功率P(KW)
0.5
電機(jī)選擇
根據(jù)鏈輪的速率知整個系統(tǒng)的轉(zhuǎn)速都非常小,估計在在20-60之間.所以盡量選轉(zhuǎn)速小的電機(jī),以免使同步帶帶輪尺寸過大而不便設(shè)計和安裝。下表是YCJ系列部分齒輪減速電動機(jī)基本型譜
減速機(jī)中心高H/mm
電動機(jī)功率P/KW
輸出轉(zhuǎn)速
n/()
輸出轉(zhuǎn)距
電 動 機(jī)
輸出軸軸徑
機(jī)座號
端蓋序號
極數(shù)
132
0.55
57
86
801
F2
4
52
96
47.5
104
43
115
36
135
所以在這選擇YCJ序列減速機(jī)中心高為132mm,輸出轉(zhuǎn)速為43的減速電機(jī)。
2.2櫻桃番茄主要參數(shù)
設(shè)計之前對櫻桃番茄分成大,中,小三個等級,分別選20個測量出各項(xiàng)參數(shù)并分別求出平均值。個參數(shù)測量數(shù)據(jù)如下表1:
級別類型
測量樣本數(shù)(個)
測量質(zhì)量平均值(g)
測量平均長徑
(mm)
測量平均段徑
(mm)
大
20
19.5
46.3
30.4
中
20
14.8
31.6
22.7
小
20
5.9
18.0
12.0
表1
從表中可以看出,櫻桃番茄主要物理參數(shù)有三中,單在本機(jī)器中是通過圖像處理來辨別它的大小。因此必須選擇櫻桃番茄的長徑或鍛徑來進(jìn)行分級。由數(shù)據(jù)可以以得出各級的長徑和短徑比都接近1.5.故選長徑或短徑都可以,在這選擇櫻桃番茄的長徑來作為標(biāo)準(zhǔn)進(jìn)行分級。分級如下:
第一級:長徑小于20mm.
第二級:長徑介于20mm和35mm.之間。
第三級:長徑大于35mm.
第三章 傳動系統(tǒng)設(shè)計
經(jīng)分析此機(jī)構(gòu)主要包括機(jī)架,定制的雙側(cè)套筒傳動鏈,滾子,雙側(cè)鏈輪,軸承,軸,軸承套,同步帶和同步帶輪要進(jìn)行設(shè)計。
3.1鏈條和鏈輪的設(shè)計
在設(shè)計此機(jī)構(gòu)的過程中,分別可以用帶傳動和鏈傳動來傳輸載體櫻桃番茄。但是由于帶傳動中傳動帶的材料不是完全的彈性體因而帶在工作一段時間后會發(fā)生塑性伸長而松弛使張緊力降低,從而使傳動不是勻速進(jìn)行的。而在本機(jī)構(gòu)中要求的是傳動中需保持絕對的勻速。所以不用帶傳動。
而鏈傳動由于經(jīng)濟(jì),可靠,它廣泛用于各類制造業(yè)中的機(jī)械上來傳遞動力。它相對于帶傳動的優(yōu)點(diǎn)是,沒有彈性滑動和打滑,能保持準(zhǔn)確的平均傳動比。需要的張緊力小,作用在軸上的壓力也小,工況相同時,傳動尺寸較緊湊。能在溫度較高,濕度較大,有油污等惡劣的環(huán)境下工作。效率較高(η=98%)。而且鏈傳動的制造和安裝精度要求不高,中心距較大時傳動結(jié)構(gòu)簡單。鏈傳動在傳遞功率,速度,傳動比,中心距等方面范圍很廣。目前最大傳動功率達(dá)到5000kw,最高速度達(dá)到40m/s,最大傳動比達(dá)到15,最大中心距達(dá)到8m。而在本機(jī)構(gòu)中中心距有也很大。故很適合選用鏈傳動。
傳動鏈主要有套筒鏈,套筒滾子鏈和齒形鏈。它們都已經(jīng)標(biāo)準(zhǔn)化。在本設(shè)計中要求用雙側(cè)的鏈條中間夾裝有滾子,但在標(biāo)準(zhǔn)化的鏈中他們的尺寸偏大會使的機(jī)構(gòu)過于龐大。所以根據(jù)設(shè)計需要,考慮盡可能的減小機(jī)構(gòu)的體積和節(jié)省材料。在本設(shè)計中我采用定制的鏈條。
在設(shè)計時取鏈的節(jié)距P=50.00mm.
前后鏈輪中心距a=1375mm.
3.1.1鏈輪的設(shè)計
鏈輪輪齒的齒型應(yīng)保證鏈節(jié)能夠自由地進(jìn)入和退出嚙合,在嚙合時應(yīng)保證良好的接觸,同時形狀應(yīng)盡可能簡單,并便于加工。
國家標(biāo)準(zhǔn)只規(guī)定了鏈輪的最大和最小齒槽形狀。實(shí)際齒槽形狀在最大和最小范圍內(nèi)都可用,因而鏈輪齒廓曲線的幾何形狀可以有很大的靈活性。在這采用的齒廓為“三遠(yuǎn)弧一直線”齒形。
鏈輪的尺寸計算如下:
因?yàn)楸緳C(jī)構(gòu)的傳動速率V=0.25m/s<0.6m/s.速率很低,所以在齒數(shù)的選擇上有很大的空間,在這里區(qū)齒數(shù)Z=17.
所以,分度圓直徑 d===272.1mm
齒頂圓直徑
齒根圓直徑
鏈輪齒廓圓弧直接)。
最大齒根距離
齒側(cè)凸緣直徑
鏈輪的結(jié)構(gòu)如圖2:
圖2
圖2
3.1.2鏈條的設(shè)計計算
節(jié)距p=50mm,中心距=1375mm,鏈輪齒數(shù)z=17。
1).由以上數(shù)據(jù)確定鏈條的鏈節(jié)數(shù):
節(jié)。
所以總個鏈條的節(jié)數(shù)為72節(jié)。
2).鏈傳動的受力分析:
鏈傳動安裝時,所需的張緊力不大,主要是保證鏈條松邊垂度不要過大,以免影響鏈條的正常退出嚙合和產(chǎn)生震動,跳齒和脫節(jié)現(xiàn)象。不考慮傳動中的動載荷,作用在鏈上的力有工作拉力F,離心拉力Fc和懸垂拉力。在這取帶傳動的效率。
工作拉力(N)取決于傳動功率P(KW)和鏈速V(m/s)
F=1000==1980N.
離心拉力
式中 q 表示單位長度鏈條的質(zhì)量,kg/m,在這q=5kg/m.
懸垂拉力可用求懸索拉力的方法近似求得
為垂度系數(shù)。與中心線和水平線的夾角有關(guān)。垂直分布時可取=1.0,水平布置時可取=6.5.在這是水平布置。故取=6.5。
由此得到鏈緊邊和松邊拉力為
緊邊拉力 : 。
松邊拉力 : 。
3) 靜強(qiáng)度校核:
由于鏈條的速率v=0.25m/s小于0.6m/s,而鏈速低于0.6m/s的低速鏈傳動,其主要失效形式是練條的靜力拉斷,故應(yīng)進(jìn)行靜強(qiáng)度校核。靜強(qiáng)度安全系數(shù)應(yīng)滿足下式要求
式中 表示單排鏈的極限拉伸載荷,在這取極限小值為60000N.
表示工作情況系數(shù),查表在載荷平穩(wěn)的情況下取=1.0
所以,,故符合要求。
另外,鏈條的形狀和主要加工尺寸如下圖3所示:
圖3
3.2滾子設(shè)計
在滾子設(shè)計中,技術(shù)要求不必要很高,它只是做承載作用。但是應(yīng)該選擇摩擦系數(shù)小的工程塑料作材料。以減小櫻桃番茄在被吹離時的摩擦力。所以選用化學(xué)材料聚四氟乙烯。查簡明機(jī)械零件設(shè)計手冊表1-13 工程材料的摩擦因數(shù)知聚四氟乙烯的動摩擦因數(shù)。在與鏈條的配合中可以用過盈配合使其固定在雙側(cè)鏈條的中間。簡圖如下圖 4:
圖4
3.3 軸承和軸承座的設(shè)計
1.軸承可分為滑動軸承和滾動軸承。由于滑動軸承本身具有一些獨(dú)特的優(yōu)點(diǎn):承載能力高、抗振性好、工作平穩(wěn)可靠、噪音小、壽命長等,使得它在某些特殊場合仍站有重要地位,目前他廣泛用于內(nèi)燃機(jī)、軋鋼機(jī)、大型電機(jī)及儀表、雷達(dá)、天文望遠(yuǎn)鏡等方面。、
滑動的類型很多,按軸承承受載荷方向的不同,軸承可分為徑向軸承和推立球軸承。根據(jù)其華東表面間摩擦狀態(tài)的不同,可分為液體摩擦滑動軸承、非液體摩擦滑動軸承。液體摩擦的特點(diǎn)是軸頸和軸承兩想對運(yùn)動表面間完全被一層油膜所分開,而根據(jù)油膜形成原理的不同,還可分為液體動力潤滑軸承和液體靜力潤滑軸承。
滾動軸承是現(xiàn)代機(jī)器中廣泛應(yīng)用的部件之一,它是依靠主要元件間的滾動接觸來轉(zhuǎn)動零件的。與滑動軸承相比,滾動軸承的主要優(yōu)點(diǎn)是:(1)摩擦力矩和發(fā)熱較小,在通常的速度范圍內(nèi),摩擦力矩很少隨速度而改變。啟動轉(zhuǎn)矩比滑動軸承的要低得多(比后者小80%-90%);(2)維護(hù)比較方便,潤滑劑較少,(3)軸承單位寬度的承載能力較大;(4)大大地減少有色金屬的消耗。
滾動軸承的缺點(diǎn)是:(1)徑向外廊尺寸比滑動軸承大;(2)接觸應(yīng)力高,承受沖擊載荷能力較差,高速重負(fù)荷小壽命較低;(3)小批生產(chǎn)特殊的滾動軸承時成本較高;(4)減振能力比滑動軸承低(5)運(yùn)轉(zhuǎn)時有噪音,不適合用于有沖擊和瞬間過載的高轉(zhuǎn)速場合。
常用的滾動軸承絕大多數(shù)已經(jīng)標(biāo)準(zhǔn)化,并由專業(yè)的工廠大量制造及供應(yīng)各種常用規(guī)格的軸承,因?yàn)閭鬏敺旨墮C(jī)需要的軸承載荷并不太大,而;而且傳輸分級機(jī)在正常工作時基本沒有減振、沖擊和瞬間過載的高轉(zhuǎn)速。所以選用滾動軸承。這樣比較有利于機(jī)器更換,從經(jīng)濟(jì)的角度上來講也節(jié)約了制造成本。
選用滾動軸承中的深溝球軸承,因?yàn)槠漭S向緊固簡單,支承結(jié)構(gòu)的軸向尺寸??;密封性好潤滑簡單;自動調(diào)心內(nèi)圈較寬便于裝拆。
3.3.1軸承的選擇
左圖為深溝球軸承的基本尺寸和和狀尺寸示意圖,下表為0系列深溝球軸承的選用表。深溝球軸承在傳輸分級機(jī)的正常工作載荷遠(yuǎn)遠(yuǎn)小于軸承的基本額定載荷,所以選用軸承主要是根據(jù)軸端的安裝來選的。在這選用代號為6008的深溝球軸承。
軸承型號
基本尺寸(mm)
安裝尺寸(mm)
基本額定載荷(KN)
d
D
B
da(min)
Da(max)
(max)
6005
25
47
12
30
43
0.6
7.9
5.05
6006
30
55
13
36
50
1
10.4
7
6007
35
62
14
41
57
1
12.5
8.7
6008
40
68
15
46
63
1
13.2
9.45
6009
45
75
16
51
70
1
16.3
12.4
6010
50
80
16
56
75
1
16.3
12.4
6011
55
90
18
63
83
1.2
22.1
17.3
3.3.1 軸和軸承的安裝方式
軸承和軸承座以及軸和軸承的連接形式如下圖5:
圖5
3.4同步帶和同步帶輪設(shè)計
在本設(shè)計中,鏈輪的主動軸是由電動機(jī)通過同步帶來驅(qū)動的。不同于其他帶傳動同步帶的工作面有齒,帶輪的輪緣表面也有相應(yīng)的齒槽,帶與帶輪是靠嚙合進(jìn)行傳動的,故傳動比恒定。
同步帶通常以鋼絲繩或玻璃纖維作承載層,氯丁橡膠或聚胺脂作基體。帶薄而且輕,可用于高速,傳動效率最高可達(dá)98%,所以同步帶的應(yīng)用非常的廣泛。其主要缺點(diǎn)就是制作和安裝精度要求較高,中心距要求較嚴(yán)格。
在規(guī)定張緊力下,相鄰兩齒中心線的直線距離叫節(jié)距,它是同步帶傳動的主要參數(shù)。同步帶有單面帶和雙面帶兩種,單面帶單面有齒,雙面帶兩面均有齒。同步帶也 已經(jīng)有標(biāo)準(zhǔn)化了,它的型號分為最輕型MXL,超輕型XXL,特輕型XL,輕型L,重型H,特重型XH,超重型XXH七中(GB11362-89)。
同步齒形帶帶輪的齒形采用漸開線齒型,可以用范成法加工而成,也可采用直邊齒形。
3.4.1同步帶選擇
根據(jù)帶傳動的功率P=0.55KW.查簡明機(jī)械零件設(shè)計手冊帶傳動動設(shè)計同步帶選型圖,在這選擇型號為H的同步帶。
同步帶尺寸和形狀如下圖6:
圖6
3.4.2同步帶帶輪設(shè)計計算
根據(jù)鏈輪線速度v=0.25m/s.可以得出主鏈輪的角速度
W=
得出大帶輪的轉(zhuǎn)速 。
1.小帶輪設(shè)計計算
由于整個機(jī)構(gòu)的轉(zhuǎn)速都非常的?。╪<750r/min)。根據(jù)簡明機(jī)械零件設(shè)計手冊表7-26 同步帶最小許用齒數(shù)(GB11361-89) H型同步帶的小帶輪齒數(shù)選擇為=14.
根據(jù)H型同步帶尺寸表:帶輪的節(jié)距。
小帶輪節(jié)圓直徑d=56.60mm
2.大帶輪設(shè)計計算
根據(jù)電機(jī)的轉(zhuǎn)速/min,鏈輪轉(zhuǎn)速/min
可以得出小帶輪和大帶輪的傳動比
所以大帶輪的節(jié)圓直徑
由 式 得大帶輪齒數(shù)為=35
圖7
3.5軸的設(shè)計
軸的結(jié)構(gòu)設(shè)計是根據(jù)軸上零件的安裝,定位以及軸的制造工藝等方面的要求,合理的確定軸的解構(gòu)形式和尺寸。軸的結(jié)構(gòu)設(shè)計不合理,會影響軸的工作能力和軸上零件的工作可靠度,還會曾加軸的制造成本和軸上零件裝配的困難。
在本設(shè)計中,有連接前鏈輪以及同步帶的主動軸和連接后鏈輪的軸。他們在結(jié)構(gòu)和尺寸上都有一定的差異,后軸相對于前主軸來說要簡單一些。而且在承受的扭轉(zhuǎn)切應(yīng)力要小一些。軸的材料主要是碳鋼和合金鋼。鋼軸的毛胚多數(shù)用軋制圓鋼和鍛件,有的直接用圓鋼。由于碳鋼比合金鋼價廉,對應(yīng)力集中的敏感性較低,同時也可以用熱處理和化學(xué)處理的辦法提高其耐磨性和抗疲勞強(qiáng)度,故在這里采用碳鋼制作軸。
3.5.1主動軸設(shè)計及校核
主動軸連接的零件有鏈輪,同步帶輪以及軸承。結(jié)構(gòu)尺寸相對來說要復(fù)雜一些,因?yàn)樗仨毻瑫r控制多個零件的軸向和徑向移動,而且各零件的裝配尺寸又有很大的差異。
由于機(jī)械傳輸?shù)墓β什淮?,對其重量和尺寸也沒有特殊要求故選擇常用材料45號鋼,調(diào)質(zhì)處理。
計算軸的最小許用軸徑
C--為取決于軸材料的許用扭轉(zhuǎn)切應(yīng)力的系數(shù),查表得45號鋼的C值為107至118之間。在這區(qū)C=110.
--帶傳動效率
--電機(jī)功率
在本設(shè)計中,零件的徑向固定是通過鍵和鍵槽來實(shí)現(xiàn)的,這也是最簡單有效的方法,而軸向移動的控制者是通過軸肩以及一端加緊固螺紋來實(shí)現(xiàn)的。根據(jù)鏈輪,軸承以及大同步帶輪的尺寸設(shè)計出軸的結(jié)構(gòu)和尺寸如下圖8:
圖8
3.5.2從動軸設(shè)計
從動軸跟主動軸尺寸和結(jié)構(gòu)相比只是少了連接同步帶輪的伸出部分,其他部分結(jié)構(gòu)和尺寸相同。其結(jié)構(gòu)和尺寸如下圖9:
圖9
第四章 安裝結(jié)構(gòu)設(shè)計計算
4.1機(jī)架設(shè)計
機(jī)架是各種機(jī)器的基本部件,在以臺機(jī)器的總質(zhì)量中占有很大的比例。整個機(jī)構(gòu)是固定在機(jī)架上實(shí)現(xiàn)運(yùn)動和傳輸?shù)?,機(jī)架又是固定在底做上的,因此結(jié)構(gòu)的工作精度及抗震性能,耐磨性和機(jī)構(gòu)能否平穩(wěn)安全的進(jìn)行工作,都和機(jī)架有關(guān)聯(lián)。因此,機(jī)架和底座的設(shè)計是至關(guān)重要的。所以正確選擇機(jī)架零件的材料和正確設(shè)計其結(jié)構(gòu)尺寸,對減小機(jī)器質(zhì)量,節(jié)約材料,提高工作精度,增強(qiáng)機(jī)器鋼度及耐磨性,曾加整個機(jī)器的美觀性有很重要的作用。而在本設(shè)計中機(jī)架的精度和表面粗糙度方面要求不高。
4.1.1機(jī)架材料選擇
機(jī)架主要有鑄造機(jī)架,焊接機(jī)架,花崗巖機(jī)架和鋼筋混凝土機(jī)架??紤]到經(jīng)濟(jì)實(shí)用性,在這我選擇鑄造機(jī)架。常用的鑄造機(jī)架材料有鑄鐵,鑄鋼和鑄造鋁合金。為方便結(jié)構(gòu)的美觀和方便拆卸,選擇者鑄造鋁合金作為本設(shè)計機(jī)構(gòu)的機(jī)架材料。鑄造鋁合金通過熱處理強(qiáng)化可使其具有足夠高的強(qiáng)度,較好的塑性,良好的低溫韌性和耐熱性。
機(jī)架的橫斷面和連接方式如下圖10:
4.1.2 機(jī)架連接方式
圖 10
總結(jié)
首先,在這我衷心的感謝在本畢業(yè)設(shè)計中給與我細(xì)心指導(dǎo)我的劉仲壽老師,正是在劉老師的悉心輔導(dǎo)下本畢業(yè)設(shè)計才得以順利的按時完成。通過做本次畢業(yè)設(shè)計我深刻的認(rèn)識到無論是在做畢業(yè)設(shè)計還是在其他的工作中和學(xué)習(xí)中都必須抱有嚴(yán)謹(jǐn)悉心的態(tài)度,只有這樣才能把事情做好,做到有突破性。另外通過本次畢業(yè)設(shè)計還使我認(rèn)識到在生活中你會感受到許多的坎坷和挫折,許多的事情并不是你不行,而是你沒有勇氣去嘗試,其實(shí)如果你嘗試了,也許就會成功,不去嘗試的話,永遠(yuǎn)都不會知道你會成功。歌德說過:那些是你的夢想的,那你就要去做,去嘗試,去努力,去奮斗。
其次,此次畢業(yè)設(shè)計是我們從大學(xué)畢業(yè)生走向未來工程師重要的一步。從最初的選題,開題到計算、繪圖直到完成設(shè)計。其間,查找資料,老師指導(dǎo),與同學(xué)交流,反復(fù)修改圖紙,每一個過程都是對自己能力的一次檢驗(yàn)和充實(shí)。通過這次實(shí)踐,我了解了分級系統(tǒng)的用途及工作原理,熟悉了分級系統(tǒng)的設(shè)計步驟,鍛煉了工程設(shè)計實(shí)踐能力,培養(yǎng)了自己獨(dú)立設(shè)計能力。此次畢業(yè)設(shè)計是對我專業(yè)知識和專業(yè)基礎(chǔ)知識一次實(shí)際檢驗(yàn)和鞏固,同時也是走向工作崗位前的一次熱身。
第三,畢業(yè)設(shè)計收獲很多,比如學(xué)會了查找相關(guān)資料相關(guān)標(biāo)準(zhǔn),分析數(shù)據(jù),提高了自己的繪圖能力,懂得了許多經(jīng)驗(yàn)公式的獲得是前人不懈努力的結(jié)果。同時,仍有很多課題需要后輩去努力去完善。 但是畢業(yè)設(shè)計也暴露出自己專業(yè)基礎(chǔ)的很多不足之處。比如缺乏綜合應(yīng)用專業(yè)知識的能力,對材料的不了解,等等。這次實(shí)踐是對自己大學(xué)四年所學(xué)的一次大檢閱,使我明白自己知識還很淺薄,雖然馬上要畢業(yè)了,但是自己的求學(xué)之路還很長,以后更應(yīng)該在工作中學(xué)習(xí),努力使自己 成為一個對社會有所貢獻(xiàn)的人,為中國制造業(yè)添上自己的微薄之力。
參考文獻(xiàn)
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【2】成大先主編,機(jī)械設(shè)計圖冊,化學(xué)工業(yè)出版社,1997。
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2006。
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21
編號
無錫太湖學(xué)院
畢業(yè)設(shè)計(論文)
相關(guān)資料
題目: 工業(yè)窯爐的設(shè)計(輸送裝置)
信機(jī) 系 機(jī)械工程及自動化 專業(yè)
學(xué) 號: 0923220
學(xué)生姓名: 李 歡
指導(dǎo)教師: 徐偉明(職稱: 教 授 )
(職稱: )
2013年5月25日
目 錄
一、畢業(yè)設(shè)計(論文)開題報告
二、畢業(yè)設(shè)計(論文)外文資料翻譯及原文
三、學(xué)生“畢業(yè)論文(論文)計劃、進(jìn)度、檢查及落實(shí)表”
四、實(shí)習(xí)鑒定表
無錫太湖學(xué)院
畢業(yè)設(shè)計(論文)
開題報告
題目: 工業(yè)窯爐的設(shè)計(輸送裝置)
信機(jī)系 機(jī)械工程及自動化 專業(yè)
學(xué) 號: 0923220
學(xué)生姓名: 李 歡
指導(dǎo)教師: 徐偉明(職稱: 教 授 )
(職稱: )
2012年11月20日
課題來源
本課題來源于導(dǎo)師布置的任務(wù)導(dǎo)老師
科學(xué)依據(jù)(包括課題的科學(xué)意義;國內(nèi)外研究概況、水平和發(fā)展趨勢;應(yīng)用前景等)
輸送裝置的設(shè)計是機(jī)械工程及其自動化專業(yè)所包含的一個較為基礎(chǔ)的內(nèi)容,選擇輸送裝置方向的畢業(yè)設(shè)計題目完全符合本專業(yè)的要求,從應(yīng)用性方面來說,輸送裝置又是很多機(jī)器所必不可少的一個部分。有效保證輸送裝置的功率及穩(wěn)定性能夠達(dá)到設(shè)計的要求,具有很好的發(fā)展前途和應(yīng)用前景。
研究內(nèi)容
1、 選擇電動機(jī),計算傳動裝置的運(yùn)動和動力參數(shù);
2、 擬定、分析傳動裝置的運(yùn)動和動力參數(shù);
3、 進(jìn)行傳動件的設(shè)計計算,校核軸、軸承、聯(lián)軸器、鍵等;
4、 繪制減速器裝配圖及典型零件圖(圖紙數(shù)達(dá)到3張或以上);
5、 完成設(shè)計說明一份,分析明晰,計算正確,闡述清楚。適合的生產(chǎn)加工工 藝
擬采取的研究方法、技術(shù)路線、實(shí)驗(yàn)方案及可行性分析
首先確定整體設(shè)計方案,由公式的演算得到電動機(jī)的動力和運(yùn)動分析,在以此推算相配的傳動件,軸系零部件的尺寸規(guī)格。綜上計算可以得到相關(guān)尺寸,再根據(jù)力學(xué)性能對所得零部件尺寸進(jìn)行校驗(yàn)從而驗(yàn)證整體方案是否可行。
研究計劃及預(yù)期成果
研究計劃:
2012年11月 布置任務(wù)。
2013年1月 對課題研究方向進(jìn)行學(xué)習(xí)
2013年2月~3月 擬定方案,提出專機(jī)總體方案,供討論
2013年4月5日~10日 確定方案,專機(jī)總體布置
11日~20日 整機(jī)設(shè)計、部件設(shè)計
21日~30日 改進(jìn)并完成設(shè)計
2013年5月1日~10日 撰寫設(shè)計說明書
11日~15日 總結(jié)
預(yù)期成果:圖紙、設(shè)計說明書
特色或創(chuàng)新之處
帶式輸送機(jī)本身便具有價格便宜,標(biāo)準(zhǔn)化程度高特點(diǎn),使成本大幅降低。高速級齒輪常布置在遠(yuǎn)離扭矩輸入端的一邊,以減小因彎曲變形所引起的載荷沿齒寬分布不均現(xiàn)象。
已具備的條件和尚需解決的問題
與指導(dǎo)老師的溝通中,對自己所做課題有了整體的認(rèn)識,清晰了思路。指導(dǎo)老師提供了論文指導(dǎo),從而使自己明確了每一步的方向。因第一次繪制復(fù)雜的裝配圖,所以在繪圖方面還有待提高。
指導(dǎo)教師意見
同意作為本專業(yè)學(xué)生畢業(yè)設(shè)計課題,其難度和工作量均合適。
指導(dǎo)教師簽名:
年 月 日
教研室(學(xué)科組、研究所)意見
教研室主任簽名:
年 月 日
系意見
主管領(lǐng)導(dǎo)簽名:
年 月 日
英文原文
Esign of Speed Belt Conveyors
G. Lodewijks, The Netherlands.
This 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 it's 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.
Belt machine by conveyor belt continuous or intermittent motion to transport all kinds of different things ,Can transport all kinds of bulk materials, but also transport a variety of cardboard boxes, packaging bags, weight of single pieces of small goods, a wide range of uses . Belt conveyor belt material: rubber, silicone, PVC, PU and other materials, in addition to ordinary material conveying, but also to meet the transmission oil resistant, corrosion resistance, antistatic and other special requirements for material. Belt conveyor structure: groove belt machine, flat belt conveyor, climbing belt machine, turning machines and other forms belt, conveyor belt can also be created to enhance the tailgate, skirts and other accessories, can meet a variety of technological requirements.The belt conveyor drive: deceleration motor drive, electric drive roller.Belt conveyor mode: frequency control, stepless transmission.The belt rack material: carbon steel, stainless steel, aluminum profile.Scope of application: light industry, electronics, food, chemical, wood, etc..Belt machine equipment characteristics: belt conveyor is stable, the material and the conveyor belt there is no relative motion, to avoid damage to the carrier material. Low noise, suitable for quiet work environment requirements. Simple structure, easy maintenance. Low energy consumption, low use cost.
Conveyor is a common don't have flexible traction component continuous conveying machinery, also called continuous conveyor.It is a material handling equipment, it with handling ability strong, persistent, direction, flexible, and other advantages in industrial production in large being applied. Although many types of belt conveyor, but its working principle is basic similar, most are driving draught device and drive transmission container transport materials. Conveyor can undertake level, the tilt and vertical conveyor, also can make the space transport routes, transmission lines is usually fixed, is a modern production and logistics transport indispensable important mechanical equipment. It has transmission capacity is strong, long distance transportation etc.
With the development of industry, conveyor also obtained fast development, conveyor products have been also gradually improved. With the emergence of the power equipment of similar principle is applied, conveyor continuing into the 19th century, britons use basketwork, wire rope for traction belt conveyor. The principle of belt conveyor, when applied in the 17th century also recorded conveyor, in 1880 German company developed driven by steam belt conveyor. Then the British and German and launched inertial conveyor, if the conveyor belt, the application of the principle, creating a tilt of the belt conveyor, belt, traction with chains. All sorts of conveyor during this time arise conveyor, based on human, hydraulic power drive such. All the structures conveyor successively appeared. In 1887 americans produced the screw conveyor, make enterprise internal, between enterprise and inter-city transportation possible. The development history of belt conveyor, they very ancient instead of the original motive for conveyor provide driving force. Ancient people began to use water overturned and high TongChe conveyor, in turn after the water conservancy project's belt conveyor begin in power. Quick-tempered exalts
According to the mode of operation conveying machinery can be divided into: 1: belt conveyor 2: screw conveyor 3: dou pattern lift machine
The future of large scale, will toward belt use scope, energy consumption, low pollution less, material automatically grading, etc.
Past 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].
Design fine-tuning, determination of the optimum starting and stopping procedures, including determination of the required control algorithms, and determination of the settings and sizes of conveyor components such as drives, brakes and flywheels, are determined by dynamic design methods. In these design methods, also referred to as dynamic analyses, the belt is assumed to be a three-dimensional (visco-) elastic body. A three dimensional wave theory should be used to study time dependent transmission of large local force and displacement disturbances along the belt [7]. In this theory the belt is divided into a series of finite elements. The finite elements incorporate (visco-) elastic springs and masses. The constitutive characteristics of the finite elements must represent the rheological characteristics of the belt. Dynamic analysis produces the belt tension and power consumption during non-stationary operation, like starting and stopping, of the belt conveyor.
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.
Many methods of analyzing a belt’s physical behavior as a rheological spring have been studied and various techniques have been used. An appropriate model needs to address:
1. Elastic modulus of the belt longitudinal tensile member
2. Resistances to motion which are velocity dependent (i.e. idlers)
3. Viscoelastic losses due to rubber-idler indentation
4. Apparent belt modulus changes due to belt sag between idlers
Since the mathematics necessary to solve these dynamic problems are very complex, it is not the goal of this presentation to detail the theoretical basis of dynamic analysis. Rather, the purpose is to stress that as belt lengths increase and as horizontal curves and distributed power becomes more common, the importance of dynamic analysis taking belt elasticity into account is vital to properly develop control algorithms during both stopping and starting.
Using the 8.5 km conveyor in Figure 23 as an example, two simulations of starting were performed to compare control algorithms. With a 2x1000 kW drive installed at the head end, a 2x1000 kW drive at a midpoint carry side location and a 1x1000kW drive at the tail, extreme care must be taken to insure proper coordination of all drives is maintained.
Figure 27 illustrates a 90 second start with very poor coordination and severe oscillations in torque with corresponding oscillations in velocity and belt tensions. The T1/T2 slip ratio indicates drive slip could occur. Figure 28 shows the corresponding charts from a relatively good 180 second start coordinated to safely and
smoothly accelerate the conveyor.
Figure 27-120 Sec Poor Start
BELTSPEED
BELT SPEED SELECTION
The 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.
Figure 1: Belt width versus belt speed for different capacities.
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.
BELT SPEED VARIATION
The 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].
Varying the belt speed with supplied bulk material flow has the following advantages:
Less belt wear at the loading areas
Lower noise emission
Improved operating behavior as a result of better belt alignment and the avoidance of belt lifting in concave curve by reducing belt tensions
Drawbacks include:
Investment cost for controllability of the drive and brake systems
Variation of discharge parabola with belt speed variation
Control system required for controlling individual conveyors in a conveyor system
Constant high belt pre-tension
Constant high bulk material load on the idler rolls
An analysis should be made of the expected energy savings to determine whether it is worth the effort of installing a more expensive, more complex conveyor system.
ENERGY CONSUMPTION
Clients may request a specification of the energy consumption of a conveyor system, for example quantified in terms of maximum kW-hr/ton/km, to transport the bulk solid material at the design specifications over the projected route. For long overland systems, the energy consumption is mainly determined by the work done to overcome the indentation rolling resistance [9]. This is the resistance that the belt experiences due to the visco-elastic (time delayed) response of the rubber belt cover to the indentation of the idler roll. For in-plant belt conveyors, work done to overcome side resistances that occur mainly in the loading area also affects the energy consumption. Side resistances include the resistance due to friction on the side walls of the chute and resistance that occurs due to acceleration of the material at the loading point.
The required drive power of a belt conveyor is determined by the sum of the total frictional resistances and the total material lift. The frictional resistances include hysteresis losses, which can be considered as viscous (velocity dependent) friction components. It does not suffice to look just at the maximum required drive power to evaluate whether or not the energy consumption of a conveyor system is reasonable. The best method to compare the energy consumption of different transport systems is to compare their transport efficiencies.
TRANSPORT EFFICIENCY
There 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:
Continuous transport:
Slurry transport around 0.01
Belt conveyors between 0.01 and 0.1
Vibratory feeders between 0.1 and 1
Pneumatic conveyors around 1 0
Discontinuous transport:
Ship between 0.001 and 0.01
Train around 0.01
Truck between 0.05 and 0.1
INDENTATION ROLLING RESISTANCE
For long overland systems, the energy consumption is mainly determined by the work done to overcome the indentation rolling resistance. Idler rolls are made of a relatively hard material like steel or aluminum whereas conveyor belt covers are made of much softer materials like rubber or PVC. The rolls therefore indent the belt's bottom-cover when the belt moves over the idler rolls, due to the weight of the belt and bulk material on the belt. The recovery of the compressed parts of the belt's bottom cover will take some time due to its visco-elastic (time dependent) properties. The time delay in the recovery of the belt's bottom cover results in an asymmetrical stress distribution between the belt and the rolls, see Figure 2. This yields a resultant resistance force called the indentation rolling resistance force. The magnitude of this force depends on the visco-elastic properties of the cover material, the radius of the idler roll, the vertical force due to the weight of the belt and the bulk solid material, and the radius of curvature of the belt in curves in the vertical plane.
Figure 2: Asymmetric stress distribution between belt and roll [7].
It is important to know how the indentation rolling resistance depends on the belt velocity to enable selection of a proper belt velocity, [11].
Figure 3: Loss factor (tanb) of typical cove
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