花生摘果機(jī)的結(jié)構(gòu)設(shè)計(jì)【半喂入式】
花生摘果機(jī)的結(jié)構(gòu)設(shè)計(jì)【半喂入式】,半喂入式,花生摘果機(jī)的結(jié)構(gòu)設(shè)計(jì)【半喂入式】,花生,摘果機(jī),結(jié)構(gòu)設(shè)計(jì)
XXXXXX畢業(yè)設(shè)計(jì)說(shuō)明書題 目: 花生摘果機(jī)的結(jié)構(gòu)設(shè)計(jì)學(xué) 院: XXXXXX 專 業(yè):機(jī)械設(shè)計(jì)制造及其自動(dòng)化 學(xué) 號(hào): XXXXXX 姓 名: XXXXXX 指導(dǎo)教師: XXXXXX 博士 完成日期: 2012年5月27日 25目 錄中文摘要I1 前言11.1 研究目的意義11.2 國(guó)內(nèi)外研究現(xiàn)狀11.3 本設(shè)計(jì)主要研究?jī)?nèi)容和研究方法21.3.1 研究?jī)?nèi)容21.3.2 研究方法22 總體方案確定22.1 方案的選擇和確定22.2 摘果裝置的總體結(jié)構(gòu)33 傳動(dòng)方案的確定43.1電動(dòng)機(jī)的選擇和傳動(dòng)參數(shù)的設(shè)計(jì)53.1.1 釘齒條上的釘齒轉(zhuǎn)速53.1.2釘齒滾筒的轉(zhuǎn)速63.1.3 電動(dòng)機(jī)的功率63.1.4 電動(dòng)機(jī)的轉(zhuǎn)速63.2 V帶傳動(dòng)的設(shè)計(jì)73.3 帶輪的結(jié)構(gòu)設(shè)計(jì)114 滾筒裝置的設(shè)計(jì)154.1 滾筒軸裝置的設(shè)計(jì)154.1.1根據(jù)軸向定位的要求確定軸的各段直徑和長(zhǎng)度164.1.2 初步選擇滾筒軸系164.1.3軸的強(qiáng)度校核164.1.4 軸承的校核204.1.5 鍵的校核214.1.6釘齒條的設(shè)計(jì)214.1.7 釘齒條的總體結(jié)構(gòu)設(shè)計(jì)214.1.8 釘齒條及釘齒的設(shè)計(jì)224.1.9 圓盤的設(shè)計(jì)225 箱體246 機(jī)架247總結(jié)248展望25參考文獻(xiàn)25摘花生機(jī)的結(jié)構(gòu)設(shè)計(jì)指導(dǎo)老師:XXXXXX中文摘要花生摘果裝置是在傳統(tǒng)的全喂入式摘果裝置的基礎(chǔ)上為降低花生的破碎率,降低能耗等問(wèn)題上而定型的,與傳統(tǒng)的摘果裝置相比,最大的不同是采用的半喂入方式,這種方式功耗少,可靠性高,摘凈率好,破損少。適合于干花生蔓藤的花生摘果生產(chǎn),小型方便,較合適家庭作業(yè)。以電動(dòng)機(jī)為動(dòng)力源,動(dòng)力由電動(dòng)機(jī)輸出軸輸出,再通過(guò)傳動(dòng)帶傳遞到滾筒上,由滾筒摘選桿轉(zhuǎn)動(dòng)打擊使花生脫離莖桿,果實(shí)及雜物通過(guò)凹版孔落下,打碎的莖稈由出料口排出,落到風(fēng)機(jī)吸雜口排雜,選出干凈的果實(shí)從而完成全過(guò)程。關(guān)鍵詞:摘果裝置;花生;能耗,結(jié)構(gòu),設(shè)計(jì);The defloration vital structural designAbstract: Half feeding type peanut picker is rigid in the traditional all feeding type picker device based on the reduce the rate of peanut broken and power consumption. Compared to the traditional picker device, the biggest difference is the use of the half feeding type, and this type have low power consumption ,reliable working process, high picker off, and litter broken peanut. This device is suit for the production of peanut peaking in the humid southern climate , the design relatively small, more suitable foe homework, which is the foundation of study and design effective peanut harvester.Key words: type of half feeding; picker device ;peanut; power consumption; 1 前言1.1 研究目的意義花生是世界上廣泛栽培的主要油料作物。隨著農(nóng)業(yè)科技的發(fā)展,花生向良種化、機(jī)械化和區(qū)域化種植方向發(fā)展。近幾年,隨著花生種植面積、產(chǎn)量的不斷增加和農(nóng)村勞動(dòng)力的轉(zhuǎn)移,花生生產(chǎn)機(jī)械化的發(fā)展就顯得尤為重要。目前,要大力發(fā)展花生生產(chǎn)全過(guò)程的機(jī)械化,必須結(jié)合中國(guó)的國(guó)情和適應(yīng)農(nóng)村現(xiàn)有的經(jīng)濟(jì)實(shí)力。大部分花生產(chǎn)區(qū)需要分別解決花生種植過(guò)程中主要作業(yè)環(huán)節(jié)的機(jī)械化問(wèn)題,近期內(nèi)應(yīng)當(dāng)是花生的機(jī)械化播種、收獲和摘果這三個(gè)主要環(huán)節(jié)。其中,花生摘果是一項(xiàng)要求嚴(yán)格、耗時(shí)較大的作業(yè)。是花生生產(chǎn)的一個(gè)重要環(huán)節(jié)。機(jī)械化收獲是確保花生豐產(chǎn)豐收的重要保障,摘果系統(tǒng)是花生聯(lián)合收割機(jī)的“心臟”,其工作情況直接影響到聯(lián)合收割機(jī)的性能。隨著農(nóng)業(yè)產(chǎn)業(yè)結(jié)構(gòu)的調(diào)整,農(nóng)業(yè)科學(xué)研究的不斷深入,花生品種必然朝著高產(chǎn)方向發(fā)展,這也給繼續(xù)工作者提出了更高的要求,高產(chǎn)就意味這在同樣收獲作業(yè)工況下增加喂入量。 南方空氣濕度大,氣侯變化無(wú)常,花生水分含量高,從以往研究成果看,喂入量和花生水分含量對(duì)摘果性能有很大的影響。一般來(lái)說(shuō),喂入量增加,摘果系統(tǒng)負(fù)荷增大;含水量增加改變理論花生蔓的物理特性,同時(shí)也改變了摘果負(fù)荷,這兩種情況都容易增加機(jī)械系統(tǒng)負(fù)荷,降低可靠性。傳統(tǒng)的摘果主要是全喂入式,摘果的主要部件是摘果滾筒,目前國(guó)內(nèi)外主要使用的摘果方式還有半喂入式,半喂入式花生摘果對(duì)干濕蔓均可使用,主要應(yīng)用在南方地區(qū),其摘果效率與損失率受花生收獲環(huán)節(jié)植株的整齊程度及摘果機(jī)喂入影響較大,現(xiàn)有機(jī)型在摘果效率、損失率上還不穩(wěn)定,沒(méi)有得到很好的推廣。因此,為了改善摘果效果,研究摘果過(guò)程的低能耗,摘果率高的摘果裝置,是提高花生產(chǎn)業(yè)化水平的關(guān)鍵。1.2 國(guó)內(nèi)外研究現(xiàn)狀傳統(tǒng)的花生摘果方法是用手工摘果,效率低、用工多,嚴(yán)重影響經(jīng)濟(jì)效益。近幾年隨著種植花生面積的加大及花生產(chǎn)量的提高,花生摘果機(jī)的應(yīng)用逐漸增多,成為代替手工操作的便利機(jī)械。目前,我國(guó)主要推廣應(yīng)用的單功能花生摘果機(jī)可分為全喂入式和半喂入式兩類。全喂入式摘果機(jī),主要用于從曬干后的花生蔓上摘果。工作時(shí)將曬干后的花生蔓喂入摘果室,在高速轉(zhuǎn)動(dòng)的滾筒作用下,將花生果摘下來(lái)。該機(jī)型除了基本上滿足摘果的要求外,普遍存在消耗的功率大、摘果不凈、分離不清、破碎率高的缺點(diǎn)。該機(jī)型的摘果部件有切流式釘齒滾筒、軸流式釘齒滾筒、蓖梳式軸流滾筒以及差動(dòng)式螺旋滾筒等幾種。半喂入摘果機(jī)工作過(guò)程是:當(dāng)摘果機(jī)的夾持輸送鏈將花生蔓夾住,沿滾筒軸向移動(dòng),摘果滾筒將花生果摘下。該機(jī)型對(duì)于干、濕花生蔓都可使用,具有動(dòng)力消耗少,摘果后的花生蔓整齊,摘濕果質(zhì)量好、破碎率低等特點(diǎn)。但該機(jī)型工作性能不穩(wěn)定,存在結(jié)構(gòu)復(fù)雜、成本高等缺點(diǎn),僅用在花生聯(lián)合收割機(jī)上。該機(jī)型的工作部件是相向滾動(dòng)的兩個(gè)橡膠滾筒,工作時(shí)兩滾筒相向滾動(dòng)將花生果摘下。國(guó)內(nèi)外現(xiàn)有的主要機(jī)型有美國(guó)Courtesy of Lilliston M fg .Co.生產(chǎn)的LP-2型花生收獲機(jī)、Kelly Manufacturing 公司生產(chǎn)的PH-2型花生收獲機(jī),國(guó)內(nèi)主要有4HZ95型花生摘果機(jī),4HZ95型花生摘果機(jī),5H-5000花生摘果機(jī),5HZ-2800型花生摘果機(jī),花生摘果機(jī)980型,5HZ-2800A型花生摘果機(jī) ,5HZ-7000型花生摘果機(jī) ,5HZ-4000型花生摘果機(jī) ,5HZ-4700型花生摘果機(jī) ,自動(dòng)裝袋花生摘果機(jī) 。但是,由于其結(jié)構(gòu)復(fù)雜、工作可靠性等原因推廣應(yīng)用受到了限制。為此,為了改善摘果效果,降低能耗,提高摘果摘凈率,對(duì)半喂入花生摘果機(jī)的設(shè)計(jì),為花生聯(lián)合收獲機(jī)的推進(jìn)革新奠定了基礎(chǔ)。本研究結(jié)合國(guó)內(nèi)外幾種典型的摘果機(jī)具的結(jié)構(gòu)特點(diǎn)與工作原理,并通過(guò)分析其現(xiàn)狀與存在的問(wèn)題,結(jié)合實(shí)驗(yàn)探討改進(jìn)方法,以期改善花生摘果效果,為花生的摘果提供切實(shí)可行的機(jī)具。1.3 本設(shè)計(jì)主要研究?jī)?nèi)容和研究方法1.3.1 研究?jī)?nèi)容 1) 傳動(dòng)系統(tǒng)的設(shè)計(jì):大小帶輪的設(shè)計(jì)計(jì)算、V帶的選取、軸承的選擇電機(jī)選型等內(nèi)容2)摘果滾筒的設(shè)計(jì)包括:滾筒的設(shè)計(jì)、動(dòng)刀條的設(shè)計(jì)等內(nèi)容 3)夾持輸送結(jié)構(gòu)的設(shè)計(jì):夾持帶的設(shè)計(jì)、帶輪的設(shè)計(jì)、軸的選取校核等 4) 機(jī)架的設(shè)計(jì)1.3.2 研究方法 1)收集資料,進(jìn)行歸納分析 2)按給定的指標(biāo)參數(shù)在指導(dǎo)老師的幫助下完成設(shè)計(jì)任務(wù)2 總體方案確定2.1 方案的選擇和確定 摘果裝置是花生收獲機(jī)械的重要工作部件?;ㄉ?lián)合收獲機(jī)工作性能的優(yōu)劣在很大程度上取決于摘果裝置的工作性能。半喂入式花生摘果裝置能很好的利用喂入環(huán)節(jié)的改善來(lái)降低能耗,能夠滿足在干花生蔓的條件下平穩(wěn)作業(yè)。其作業(yè)原理是:花生蔓通過(guò)入料口傳送到摘果滾筒,在滾筒不斷的旋轉(zhuǎn)作用下摘果,有動(dòng)刀條上齒釘將花生蔓和花生分離開(kāi)來(lái)。其特點(diǎn)如下:1)該裝置用于花生果摘取作業(yè),可以解決晾曬后花生的摘果問(wèn)題,為設(shè)計(jì)聯(lián)合花生收獲機(jī)奠定了基礎(chǔ)。2)該裝置結(jié)構(gòu)簡(jiǎn)單,適應(yīng)性好,可以節(jié)約收獲時(shí)間,降低因?yàn)榱罆裨斐傻⒄`農(nóng)時(shí)的問(wèn)題。如果配在聯(lián)合收獲機(jī)上,效果更為顯著。3)由于該裝置采用半喂入式原理,所以其功率消耗少,工作可靠,不會(huì)出現(xiàn)莖稈莖稈殘繞或堵塞問(wèn)題,同時(shí)含雜率也較全喂入式明顯少,減輕了后續(xù)花生清選的負(fù)荷。4)但該機(jī)型工作性能不穩(wěn)定等缺點(diǎn)。2.2 摘果裝置的總體結(jié)構(gòu) 摘果裝置的主要部分為:入料口裝置、摘果滾筒裝置、出口部分、機(jī)架組成。整體組成圖由圖1所示:1) 入料和輸送裝置 入料口和上機(jī)架部分相連接,是用2mm厚的鐵板制成,入料部位與上箱蓋,下箱蓋一起,采用螺栓連接,花生蔓經(jīng)入料口進(jìn)入,由滾筒摘選桿轉(zhuǎn)動(dòng)打擊使花生脫離莖桿,在傳動(dòng)軸轉(zhuǎn)動(dòng)的過(guò)程中摘果滾筒進(jìn)行摘果。 2) 摘果裝置 摘果部分主要是由摘果滾筒和齒釘組成的摘果桿組成。兩個(gè)滾盤用螺栓連接在焊接在傳動(dòng)軸的鐵板上,滾盤上接有8條鐵條,在鐵條上相隔22mm均勻分布有長(zhǎng)為40mm的直徑為3mm的齒釘33條?;ㄉ麖娜肓峡谌朕D(zhuǎn)動(dòng)的滾筒中,花生蔓的根部先入,此過(guò)程中在摘果滾筒中間完成摘果,摘下的花生下落到下滑板上,由倉(cāng)口排出出料斗之外,摘果后的打碎的花生根莖在下落的時(shí)候由風(fēng)扇機(jī)吹出。3) 出口部分出口部分主要是下滑式鐵皮制造,也是由2mm厚的鐵皮構(gòu)造,花生滑落上面由于鐵板槽的傾斜花生滑出機(jī)體之外。4) 機(jī)架機(jī)架是花生摘果機(jī)的主要支撐,它承擔(dān)著摘果機(jī)的主要重量和動(dòng)力、負(fù)載和力矩因此它的設(shè)計(jì)是只強(qiáng)不弱的部分。機(jī)架的各部分各自穩(wěn)定,而且相對(duì)固定,以便做到機(jī)械在運(yùn)轉(zhuǎn)過(guò)程中不會(huì)產(chǎn)生晃動(dòng)、歪斜,造成人身危險(xiǎn),因此為了機(jī)架的堅(jiān)固,此試驗(yàn)臺(tái)的設(shè)計(jì)采用4mm厚的角鋼制成。5) 花生摘果裝置的總體設(shè)計(jì)為了更優(yōu)化花生摘果裝置的機(jī)型和結(jié)構(gòu)設(shè)計(jì),此花生摘果裝置的動(dòng)力裝置放在機(jī)架的下面,與機(jī)架固定,這樣不僅可以節(jié)省空間,還可以起到穩(wěn)定作用?;ㄉb置從入料到摘果到花生蔓的排除機(jī)體外是花生摘果裝置一體完成的,拿開(kāi)上箱蓋可以看到整個(gè)摘果過(guò)程,便于我們收集花生摘果的相關(guān)數(shù)據(jù)。圖1 摘果機(jī)裝配簡(jiǎn)圖Fig.1 the figure of the Assembly3 傳動(dòng)方案的確定根據(jù)花生摘果機(jī)的具體傳動(dòng)要求,可選電機(jī)與主軸之間用V帶和帶輪的傳動(dòng)方式傳動(dòng),應(yīng)為摘果機(jī)在摘果工作過(guò)程中,傳動(dòng)件V帶是一個(gè)撓性件,它賦有彈性,能緩沖和沖擊,吸收震動(dòng),因而使花生摘果機(jī)減少震動(dòng),噪音小等優(yōu)點(diǎn)。雖然在傳動(dòng)過(guò)程中V帶與帶輪之間存在一些摩擦,導(dǎo)致兩者的相對(duì)滑動(dòng),使傳動(dòng)比不精確但不會(huì)影響摘果機(jī)的傳動(dòng),因?yàn)榛ㄉ麢C(jī)不需要精確的傳動(dòng),只要傳動(dòng)比比較精確就可以滿足需求,而且V帶的彈性滑動(dòng)對(duì)摘果機(jī)的一些重要部件是一種過(guò)載保護(hù),不會(huì)造成機(jī)體部件的嚴(yán)重?fù)p壞,還有V帶及帶輪的結(jié)構(gòu)簡(jiǎn)單、制造成本低、容易維修和保養(yǎng)、便于安裝,所以,在電機(jī)和摘果機(jī)的傳送帶之間選用V帶輪的傳動(dòng)配合是很合理的。本設(shè)計(jì)中有兩處可以用到V帶的傳動(dòng),輸入系統(tǒng)和電機(jī)之間,摘果滾筒和電機(jī)之間,我們來(lái)確定輸入系統(tǒng)和電機(jī)之間的帶傳動(dòng)。方案如下:圖4 傳動(dòng)方案圖Fig 4 Transmission program figture3.1電動(dòng)機(jī)的選擇和傳動(dòng)參數(shù)的設(shè)計(jì)根據(jù)4HZ95型花生摘果機(jī)所給相關(guān)設(shè)計(jì)的參考數(shù)據(jù)條件,摘果主軸為750850,滾盤半徑150mm,滾筒長(zhǎng)890mm,在主軸的滾盤上設(shè)有八條釘齒條,每條釘齒條上均勻分布著30個(gè)釘齒,總共240個(gè)釘齒呈螺旋均勻安裝,以便玉米芯隨螺旋釘齒的螺旋作用排出機(jī)體之外,釘齒滾筒的直徑為,滾筒上的釘齒長(zhǎng)度為40。根據(jù)實(shí)踐測(cè)量得知每個(gè)釘齒的均勻受力為20,當(dāng)摘果機(jī)正常工作時(shí)釘齒滾筒上的釘齒條快速旋轉(zhuǎn),其中均有兩條釘齒條受玉米所給的切向力,而另外兩個(gè)釘齒條是空行程,因此,即玉米脫粒機(jī)正常工作時(shí),受到的切向力為600。其中:釘齒所受的力 參與工作的釘齒個(gè)數(shù) 參與工作的釘齒條數(shù)3.1.1 釘齒條上的釘齒轉(zhuǎn)速 當(dāng)摘果機(jī)的釘齒滾筒快速轉(zhuǎn)動(dòng)時(shí),其上釘齒條的釘齒同樣有一定的轉(zhuǎn)速,這個(gè)轉(zhuǎn)速原于主軸的轉(zhuǎn)速和齒釘?shù)陌霃郊矗海?其中:釘齒的轉(zhuǎn)速 脫粒機(jī)主軸的轉(zhuǎn)速 釘齒距軸心的距離3.1.2釘齒滾筒的轉(zhuǎn)速摘果機(jī)所需功率為,應(yīng)由摘果機(jī)的工作阻力和運(yùn)轉(zhuǎn)參數(shù)求定,即:,計(jì)算求得: 。3.1.3 電動(dòng)機(jī)的功率電動(dòng)機(jī)功率由公式來(lái)計(jì)算,脫粒機(jī)傳動(dòng)裝置的總效率,應(yīng)由組成傳動(dòng)裝置的各個(gè)部分運(yùn)動(dòng)副的效率只積,即 ,其中、 分別為每一個(gè)轉(zhuǎn)動(dòng)副的效率,選取傳動(dòng)副的效率值如下: 滾動(dòng)軸承(每對(duì))0.980.995 即取 =0.99 V帶傳動(dòng) 0.940.97 即取 =0.97 滾筒轉(zhuǎn)動(dòng) (因?yàn)獒旪X條固定于滾筒上) 即取 =1則 由此可得電動(dòng)機(jī)的功率:3.1.4 電動(dòng)機(jī)的轉(zhuǎn)速 根據(jù)4HZ95型花生摘果機(jī)所給相關(guān)設(shè)計(jì)的參考數(shù)據(jù)條件可得主軸的轉(zhuǎn)速在 750850,按機(jī)械設(shè)計(jì)指導(dǎo)書中表一所推薦的傳動(dòng)比合理取值范圍,取V帶的傳動(dòng)比24,即可滿足電動(dòng)機(jī)的轉(zhuǎn)速與主軸的轉(zhuǎn)速相匹配,故電動(dòng)機(jī)轉(zhuǎn)速范圍可選為:。 符合這一范圍的同步電動(dòng)機(jī)轉(zhuǎn)速的有720,1440,2900,根據(jù)容量和相關(guān)轉(zhuǎn)速,由機(jī)械設(shè)計(jì)通用手冊(cè)查出三種適宜的電動(dòng)機(jī)型號(hào),因此有三種不同的傳動(dòng)比方案,如表1: 表1 電動(dòng)機(jī)的型號(hào)和技術(shù)參數(shù)及傳動(dòng)比 方案電動(dòng)機(jī)型號(hào)額定功率電動(dòng)機(jī)轉(zhuǎn)速基本參數(shù)P/kW同步轉(zhuǎn)速滿載轉(zhuǎn)速效率(%)電動(dòng)機(jī)重量(KG)功率因數(shù)1Y160L-87.575072086.01400.802Y132M-47.51500144087.0790.853Y132S2-25.53000290086.2720.88綜臺(tái)考慮電動(dòng)機(jī)和傳動(dòng)裝置的尺寸、重量以及帶傳動(dòng)的傳動(dòng)比,可知方案2比較適合。因此選定電動(dòng)機(jī)型號(hào)為Y132M-4。所選電動(dòng)機(jī)的額定功率7.5kw,滿載轉(zhuǎn)速=14400rmin,總傳動(dòng)比適中,傳動(dòng)裝置結(jié)構(gòu)較緊湊。如表2:表2 其主要參數(shù)如下表型 號(hào) 額定功率 KW 滿 載 時(shí) 額 定 電 流額 定 轉(zhuǎn) 矩最 大 轉(zhuǎn) 矩轉(zhuǎn)速rmin 電流(380V)效 率 % 功率因數(shù)Y132M-47.5144011.687.00.8572.32.5表 電動(dòng)機(jī)尺寸列表單位中心高 H 外形尺寸底腳安裝尺寸 地腳螺栓孔直徑 軸伸尺寸 裝鍵部位尺寸 電動(dòng)機(jī)的輸出軸尺寸 1323.2 V帶傳動(dòng)的設(shè)計(jì)根據(jù)花生摘果機(jī)的具體傳動(dòng)要求,可選取電動(dòng)機(jī)和主軸之間用V帶和帶輪的傳動(dòng)方式傳動(dòng),因?yàn)樵诿摿C(jī)的工作過(guò)程中,傳動(dòng)件V帶是一個(gè)撓性件,它賦有彈性,能緩和沖擊,吸收震動(dòng),因而使花生摘果機(jī)工作平穩(wěn),噪音小等優(yōu)點(diǎn)。雖然在傳動(dòng)過(guò)程中V帶與帶輪之間存在著一些摩擦,導(dǎo)致兩者的相對(duì)滑動(dòng),使傳動(dòng)比不精確但不會(huì)影響花生摘果機(jī)的傳動(dòng),因?yàn)檎麢C(jī)不需要精確的傳動(dòng)比,只要傳動(dòng)比比較準(zhǔn)確就可以滿足要求,而且V帶的彈性滑動(dòng)對(duì)摘果機(jī)的一些重要部件是一種過(guò)載保護(hù),不會(huì)造成機(jī)體部件的嚴(yán)重?fù)p壞,還有V帶及帶倫的結(jié)構(gòu)簡(jiǎn)單、制造成本底、容易維修和保養(yǎng)、便于安裝,所以,在電動(dòng)機(jī)與摘果機(jī)機(jī)之間選用V帶與帶輪的傳動(dòng)配合是很合理的。 選擇V帶和帶輪因當(dāng)從它的傳動(dòng)參數(shù)入手,來(lái)確定V帶的型號(hào)、長(zhǎng)度和根數(shù),再來(lái)確定導(dǎo)輪的材料、結(jié)構(gòu)和尺寸(輪寬、直徑、槽數(shù)及槽的尺寸等),傳動(dòng)中心距(安裝尺寸),帶輪作用在軸的壓力(為設(shè)計(jì)軸承作好準(zhǔn)備)。 1) 確定計(jì)算功率由于機(jī)器工作環(huán)境惡劣,工作時(shí)間不超過(guò)11個(gè)小時(shí),估計(jì)算功率 其中: 工作情況系數(shù) 電動(dòng)機(jī)的功率查機(jī)械設(shè)計(jì)書中的表87可知:=1.0 摘果電機(jī)=1.06.1=6.1(KW) 2) 選擇V帶的型號(hào) 根據(jù)計(jì)算得知的功率和電動(dòng)機(jī)上的帶輪轉(zhuǎn)速(與電動(dòng)機(jī)一樣的速度),查機(jī)械設(shè)計(jì)一書88,可以選擇V帶的型號(hào)為A型系列。 3) 確定帶輪的基準(zhǔn)直徑初選電動(dòng)機(jī)的帶輪基準(zhǔn)直徑:根據(jù)機(jī)械設(shè)計(jì)一書,可選 擇V帶的型號(hào)參考表84a,選取75mm,取大摘果系統(tǒng)標(biāo)準(zhǔn)直徑=100mm,喂入系統(tǒng)=75mm,P0 =6.82KW.計(jì)算V帶的速度V: 在1020M/S范圍內(nèi),速度V符合要求 電動(dòng)機(jī)與主軸傳動(dòng)比的計(jì)算 計(jì)算從動(dòng)輪的直徑 由表選擇,取=240mm(雖然略有增大,但誤差小于5%,故允許) 確定傳動(dòng)中心距和帶長(zhǎng) 取 即:得: ?。?帶長(zhǎng) 即: 得:按機(jī)械設(shè)計(jì)基礎(chǔ)一書中查表145,選擇想近的基本長(zhǎng)度和 相對(duì)應(yīng)的公稱長(zhǎng)度(內(nèi)周長(zhǎng))可查得:, 。 實(shí)際的中心距可按下列公式求得: 也可用經(jīng)驗(yàn)公式:求得 : 驗(yàn)算主動(dòng)輪上的包角即:=180-15.85求得 : 滿足V帶傳動(dòng)的包角要求。 確定V帶的根數(shù):V帶的根數(shù)由下列公式確定: 其中 : 單根普通V帶的許用功率值 考慮包角不同大的影響系數(shù),簡(jiǎn)稱包角系數(shù) 考慮的材質(zhì)情況系數(shù),簡(jiǎn)稱材質(zhì)系數(shù),對(duì)于棉簾布和棉線繩結(jié)構(gòu) 的膠帶,取 ,對(duì)于化學(xué)線繩結(jié)構(gòu)的膠帶,取 。 計(jì)入傳動(dòng)比的影響時(shí),單根普通V帶所能傳遞的功率的增量,其計(jì)算公式如下: 式中:?jiǎn)胃胀╒帶所能傳遞的轉(zhuǎn)矩修正值 ,從機(jī)械設(shè)計(jì)基礎(chǔ)可以查表1410 主動(dòng)輪的轉(zhuǎn)速 查得: 則: 查表取值: 由 查得: 所以: 即: 取 根 計(jì)算帶的最小初拉力 查表的A型帶的單位長(zhǎng)度質(zhì)量q=0.1 kg/m 單根V帶適當(dāng)?shù)某趵τ上铝泄角蟮?其中: q傳動(dòng)帶單位長(zhǎng)度的質(zhì)量,kg/m即: =190N根據(jù)查表所得數(shù)據(jù)求得滾筒V帶質(zhì)量 =190N計(jì)算壓軸力為了設(shè)計(jì)安裝帶輪軸和軸承,必須確定V帶作用在軸上的壓力,它等于V帶兩邊的初拉力之和,忽略V帶兩邊的拉力差,則值可以近似由下式算出: 即: =2xZxcos=2xZxsin 求得得滾筒V帶壓軸力:=644.7N因?yàn)閹л喌霓D(zhuǎn)速V=7.32m/s,遠(yuǎn)遠(yuǎn)小于25m/s,所以材料選定為灰鑄鐵,硬度為HT150.因?yàn)閹л喌霓D(zhuǎn)速V=5.5m/s,遠(yuǎn)遠(yuǎn)小于25m/s,所以材料選定為灰鑄鐵,硬度為HT150.3.3 帶輪的結(jié)構(gòu)設(shè)計(jì) 帶輪的結(jié)構(gòu)設(shè)計(jì)主要是根據(jù)帶輪的基準(zhǔn)直徑,選擇帶輪的結(jié)構(gòu)形式,根據(jù)帶的型號(hào)來(lái)確定槽的尺寸,設(shè)計(jì)如下:從動(dòng)帶輪的結(jié)果選擇,因?yàn)楦鶕?jù)主動(dòng)帶輪的基準(zhǔn)直徑和傳動(dòng)比來(lái)確定,即=240mm,小于300mm,所以從動(dòng)帶輪采用輪輻式。由下圖5為摘果V帶輪 的結(jié)構(gòu)設(shè)計(jì)。 圖5 大、小帶輪結(jié)構(gòu)圖Fig5 Assumption diagram of the larger and small pulley從動(dòng)帶輪的參數(shù)選擇:通過(guò)查機(jī)械設(shè)計(jì)一書,可查的帶輪的結(jié)構(gòu)參數(shù)間表,其他一些相關(guān)尺寸可以根據(jù)相應(yīng)的經(jīng)驗(yàn)公式計(jì)算求得。根據(jù)基準(zhǔn)直徑的大小選用不同的帶輪類型,小徑帶輪采用實(shí)心式,大徑帶輪采用輪輻式,主要結(jié)構(gòu)尺寸如下:表1 大小帶輪的基本尺寸Table 1 the size of the basic size pulley單位:mm尺寸類型小帶輪大帶輪D100160基準(zhǔn)寬度1111基準(zhǔn)線上槽深2.752.75基準(zhǔn)線下槽深 8.78.7第一槽對(duì)稱面至端面距離f輪緣厚1212帶輪寬B2020外徑105.5165.5極限偏差輪轂長(zhǎng)50353224輪輻厚820161364 滾筒裝置的設(shè)計(jì)4.1 滾筒軸裝置的設(shè)計(jì)傳動(dòng)軸是花生摘果機(jī)的主要設(shè)計(jì)部件之一,它在花生摘果機(jī)正常工作過(guò)程中,承擔(dān)主要轉(zhuǎn)矩、扭矩、彎矩和支撐傳動(dòng)軸上的回轉(zhuǎn)零件,花生摘果工作過(guò)程中是很頻繁的沖擊,因此傳動(dòng)軸的設(shè)計(jì)是很關(guān)鍵的一個(gè)步驟。它的主要功用是:一是支持軸上所安裝的回轉(zhuǎn)零件,使其有確定的工作位置;二是傳遞軸上的運(yùn)動(dòng)和動(dòng)力。軸按照軸線形狀的不同,可以分為曲軸、直軸、軟軸和撓形軸等,根據(jù)花生摘果機(jī)的結(jié)構(gòu)特點(diǎn)和組成形狀及工作強(qiáng)度和環(huán)境的要求,花生摘果機(jī)的主軸選用直軸形式傳遞,而且選用直軸重的階梯軸。在此設(shè)計(jì)中有滾筒的主動(dòng)軸,和傳動(dòng)系統(tǒng)的軸,先來(lái)對(duì)滾筒的軸進(jìn)行設(shè)計(jì): 根據(jù)軸的扭轉(zhuǎn)強(qiáng)度來(lái)初步計(jì)算確定其最小直徑,可利用經(jīng)驗(yàn)公式: 其中: 軸常用的幾種材料的的值 P主軸上的功率 kw n主軸上的轉(zhuǎn)速 r/min 軸上的材料由機(jī)械設(shè)計(jì)一書中可以查到,應(yīng)選取調(diào)質(zhì)處理的45號(hào)鋼,=640MP,書中表152取=118,于是求得: d=13.98mm 取d=15mm輸出軸上的最小直徑顯然是安裝帶輪的內(nèi)孔,必在軸上開(kāi)有鍵槽,因此,為了開(kāi)鍵槽又不消耗輸出軸的強(qiáng)度,可以使軸的直徑增加5%以上,這樣增加書輸出軸的尺寸,可以提高軸的工作強(qiáng)度。即 d= d(1+5%) 16mm主輸出軸的最小直徑是安裝帶輪處的直徑,為了使所選的軸直徑與帶輪相配合,故使輸出軸端的軸徑選為16mm。在機(jī)械設(shè)計(jì)基礎(chǔ)一書。查表可以得知帶輪的厚度,則取輸出軸的次段軸徑為,其長(zhǎng)度為.4.1.1根據(jù)軸向定位的要求確定軸的各段直徑和長(zhǎng)度滾筒傳動(dòng)軸的第一級(jí)安裝帶輪,由帶輪直徑查表得知帶輪的厚度A=20mm,其輪轂長(zhǎng)度為62mm,則取第一級(jí)軸的軸徑d=16mm, 其長(zhǎng)度為40mm。該軸的徑向定位由普通的平鍵來(lái)完成。選用鍵的型號(hào)為普通平鍵,其尺寸為8x8x25。鍵的型號(hào)可以通過(guò)查機(jī)械設(shè)計(jì)一書獲得。第二級(jí)安裝軸承座和軸承和套筒,查表的該段直徑為d=50mm,長(zhǎng)度為50mm,軸套寬度是32mm,直徑為30mm。并設(shè)一5mm的軸肩,上焊有一鐵板與滾盤螺栓連接,固定滾筒。第三級(jí)安裝滾筒,查表的該段直徑d=60mm,由于有旋轉(zhuǎn)件,箱體兩側(cè)留60mm,小于套筒的長(zhǎng)度,箱體厚度為2mm,該軸的長(zhǎng)度為760mm。4.1.2 初步選擇滾筒軸系由摘果機(jī)的結(jié)構(gòu)和相關(guān)尺寸可知所設(shè)計(jì)的軸上裝有帶輪和滾筒,需要選擇軸承,又由d=50mm,初步選取支撐的軸承 深溝球軸承,在機(jī)械設(shè)計(jì)手冊(cè)查的軸承的型號(hào)為63012,它的結(jié)構(gòu)尺寸d*D*B為50、40、12,故取右邊第二段與左邊第一段的直徑相等,即d=50mm.。安裝滾筒帶的直徑為d=30mm,軸承與軸肩用軸端擋圈固定,左右端采用的軸承用軸承座固定,已知滾筒長(zhǎng)度為760mm.。滾筒軸的基本結(jié)構(gòu)如下圖6:圖6 軸的結(jié)構(gòu)示意圖 Fig6 the axis of the structure4.1.3軸的強(qiáng)度校核1) 作軸的簡(jiǎn)圖如圖6所示2) 求輸出軸上的所收受作用力的大小 根據(jù)公式:T=9550 求得 其中: p輸入功率 kw n傳動(dòng)軸的轉(zhuǎn)速 r/min即 T=9550=68.5KNm3)滾筒的圓周力 根據(jù)公式:= 求得 其中d輸出軸的軸心到動(dòng)刀中間的距離 即: =210N 根據(jù)公式: =80% 其中:80%徑向力占圓周力的百分?jǐn)?shù) 即: =168N 根據(jù)公式:=tg 由于摘果機(jī)的主軸軸向不受力, 取=0,圓周力 徑向力 軸向力的方向如圖所示7(a)4) 軸上水平面內(nèi)所收支反力如圖(b) 根據(jù)公式:F = 其中:是輸出軸上左端軸承座的中心到滾筒第一個(gè)支撐點(diǎn)的距離60mm 滾筒第一個(gè)支撐點(diǎn)到第二個(gè)支撐點(diǎn)的距離700mm 即: F =193.4N 根據(jù)公式: F=- F 即: F=210-193.4=16.6N 5) 軸在垂直面內(nèi)所收支反力如圖 由于滾筒重力是均勻分布,滾筒太長(zhǎng),我們將滾筒重看成是一個(gè)集中力。作用 點(diǎn)在滾筒中心。取滾筒重為15kg,則重力G=150N 根據(jù)公式: R= 求得 其中:D動(dòng)刀的頂端到主軸軸心的距離160mm 即 R=275N 根據(jù)公式:R=+G- R=144+150-275=19N 6) 做彎矩圖 在水平面內(nèi),軸上B、C、D三點(diǎn)的彎矩為: 根據(jù)公式: M=0 M= 求得: M=11.60.0415=0.48Nm 作水平面內(nèi)彎矩如圖(b)所示 在垂直面內(nèi),軸上BH、C、D三點(diǎn)的彎矩為: 根據(jù)公式: M=M=0 M=R 求得: M=27M50.041.5=11.4Nm 作垂直面內(nèi)彎矩圖如(c)所示 合成的彎矩為: M=0 M=11.41 Nm 作軸的合成彎矩圖如(d)所示。7) 作彎矩圖根據(jù)公式: T=9550=11.7 Nm其中: p輸出軸功率 kw作軸的彎矩圖(e)所示8) 作當(dāng)量彎矩圖 C點(diǎn) : M=13.4 Nm 式中取0.6,作軸的當(dāng)量彎矩圖(f)所示::9) 校核軸的強(qiáng)度 進(jìn)行校核時(shí),通常只校核軸上承受最大當(dāng)量彎矩的強(qiáng)度。由經(jīng)驗(yàn)公式及上面計(jì)算出的數(shù)值可得出。 公式: 式中: W軸的抗彎拋面模量,mm 軸的許用應(yīng)力,MP 按軸實(shí)際所受彎曲應(yīng)力的循環(huán)特性,選取相應(yīng)的數(shù)值,從機(jī)械設(shè)計(jì)可以查出。 =9.69MPa 按機(jī)械設(shè)計(jì)書中查的,對(duì)于=600 MPa碳鋼,承受對(duì)稱循環(huán)變應(yīng)力時(shí)的許用應(yīng)力55 MPa9.69 MPa。 喂入系統(tǒng)的軸跟上述過(guò)程校核一樣,安全。9) 校核軸的強(qiáng)度 進(jìn)行校核時(shí),通常只校核軸上承受最大當(dāng)量彎矩的強(qiáng)度。由經(jīng)驗(yàn)公式及上面計(jì)算出的數(shù)值可得出。 公式: 式中: W軸的抗彎拋面模量,mm 軸的許用應(yīng)力,MP 按軸實(shí)際所受彎曲應(yīng)力的循環(huán)特性,選取相應(yīng)的數(shù)值,從機(jī)械設(shè)計(jì)可以查出。 =9.69MPa 按機(jī)械設(shè)計(jì)書中查的,對(duì)于=600 MPa碳鋼,承受對(duì)稱循環(huán)變應(yīng)力時(shí)的許用應(yīng)力55 MPa9.69 MPa。圖7 受力分析圖Fig 7 Force Analyse 喂入系統(tǒng)的軸跟上述過(guò)程校核一樣,安全。4.1.4 軸承的校核 由于滾筒兩軸承型號(hào)一樣,所以承受力相差不多,所以在這里任選一軸承校核,對(duì)深溝球軸承,查機(jī)械設(shè)計(jì)一書知徑向基本額定載荷 =由機(jī)械設(shè)計(jì)課程設(shè)計(jì)表(61)查的63012深溝球軸承基本額定動(dòng)載荷C=9.38KN,查表的=1,=1.1,對(duì)球軸承,=3,將以上相關(guān)數(shù)據(jù)代入上式,的 9380= P=693.2N 故在規(guī)定條件下,63012軸承可承受的最大徑向載荷為693.2N,遠(yuǎn)大于軸承的徑向載 荷11.6N和168.4N。故所選軸承合格。4.1.5 鍵的校核 由于載荷在鍵的工作面上大致分布均勻,我們這里可以用校核普通平鍵的方法來(lái)校核: 即: =14.6MPa=60 MPa3.1 4.1.6釘齒條的設(shè)計(jì) 釘齒條是摘果機(jī)的主要脫離部件,它的設(shè)計(jì)關(guān)系到花生摘果的質(zhì)量的好壞,直接關(guān)系到花生摘果機(jī)正常工作時(shí)整體的摘果效果以及摘果時(shí)后將花生和蔓藤分離的情況,它的功能是采用脫離滾筒上的八條釘齒摘果桿,均勻快速的轉(zhuǎn)動(dòng),工作時(shí)將干花生蔓藤塞入摘果機(jī)中,主軸的轉(zhuǎn)動(dòng)帶動(dòng)固定在釘齒滾筒上的釘齒,釘齒的頂端以一定的速度去對(duì)花生摘果(將花生從蔓藤上進(jìn)行強(qiáng)行分離)?;ㄉ诮?jīng)過(guò)釘齒條的快速旋轉(zhuǎn)下摘除,八條釘齒條上的釘齒交叉均勻排列,目的在于將花生蔓藤跟釘齒的打動(dòng)摘除排出機(jī)體之外,同時(shí),每一條釘齒條上的釘齒同樣在進(jìn)行摘果,以便達(dá)到有較高的摘果率。花生摘果機(jī)的主要功能是將花生跟蔓藤分離,將蔓藤打碎。而釘齒條在工作中起到了重要作用,因此,釘齒條的設(shè)計(jì)是脫粒機(jī)的設(shè)計(jì)的主要部件。4.1.7 釘齒條的總體結(jié)構(gòu)設(shè)計(jì) 從釘齒條的功用及其工作要求可以判斷出釘齒的工作強(qiáng)度很大,根據(jù)根據(jù)4HZ95型花生摘果機(jī)得知花生摘果機(jī)的釘齒滾筒上安裝有八條釘齒條,相互之間相差45,而且每條釘齒條上安裝釘齒的個(gè)數(shù)范圍在3033個(gè)釘齒,每一個(gè)釘齒的 ,八條釘齒條均勻安裝在釘齒滾盤上,釘齒在釘齒條上均勻的承螺旋排列方式安裝,兩相鄰的釘齒條之間的釘齒橫向距離為,且承兩條螺旋均勻排列,在釘齒條的兩端分別用一個(gè)厚度是,直徑是的圓盤固定,在兩個(gè)圓盤上均勻開(kāi)有釘齒條寬厚的方孔,四個(gè)方通孔均勻承分布,然后將八條釘齒條從八個(gè)方孔中穿過(guò),同樣,在釘齒條的另一端也用厚度一樣但直徑為的圓盤固定,是釘齒條穿過(guò)方孔而且在圓盤的表面漏出23,因?yàn)檫B接時(shí)是采用焊接完成,方便焊接。這樣結(jié)構(gòu)更加堅(jiān)固、穩(wěn)定、可靠。圓盤將釘齒條固定,但由于釘齒條過(guò)長(zhǎng)(即),因此,在主軸的三分之一處和三分之二處,采用直徑是的鐵柱使釘齒條與主軸相連,它們的連接方式采用焊接式,這樣可以增加釘齒條的剛度,以便釘齒條受到更大的強(qiáng)度時(shí)不宜損壞,同時(shí)也使軸的扭轉(zhuǎn)剛度和彎曲剛度有很大的增加,使釘齒條的扭轉(zhuǎn)剛度和彎曲剛度增加,這樣可以使釘齒滾筒的整體剛度和強(qiáng)度極大增加,主軸和釘齒滾筒之間的固定性好,穩(wěn)定性高等優(yōu)點(diǎn)。4.1.8 釘齒條及釘齒的設(shè)計(jì) 釘齒條的功用是固定釘齒的相對(duì)位置,使釘齒在正常工作過(guò)程中能夠持續(xù)的正常工作,釘齒所受的脫粒力直接傳遞到釘齒條上,釘齒條所承受著釘齒的切向力,所以釘齒條應(yīng)該采用足夠強(qiáng)度和剛度的材料制成,根據(jù)根據(jù)4HZ95型花生摘果機(jī)中,可以查得材料選為45鋼,宗上所述,設(shè)計(jì)的釘齒條的長(zhǎng)寬 為,其上分布著釘齒,每個(gè)釘齒條上均勻分布著30-33個(gè)釘齒,每個(gè)釘齒均穿過(guò)釘齒條,然后焊接,其中釘齒條上的通孔設(shè)計(jì)為圓柱型,它的直徑為,而且,在釘齒條上通孔的上端開(kāi)有長(zhǎng)為,高為,寬為的小槽,目的是為了在釘齒安裝在釘齒條上時(shí),這個(gè)小槽可以和釘齒上的凸楞相配合,這樣可以使釘齒在釘齒條上周向固定,而且在釘齒正常工作時(shí),也同樣使釘齒相對(duì)釘齒條固定,不宜使工作時(shí)釘齒和釘齒條脫落,其結(jié)構(gòu)如圖8: 圖8釘齒條結(jié)構(gòu)圖4.1.9 圓盤的設(shè)計(jì) 圓盤是將釘齒條與主軸固定的主要部件,它不僅起連接作用,而且還可以承擔(dān)釘齒和釘齒條傳遞的力矩和彎曲及扭轉(zhuǎn)強(qiáng)度,它位與釘齒條的兩端,且采用焊接式連接,同時(shí)與主軸也要相對(duì)固定,采用設(shè)一5*10mm軸肩,將一50mm鐵板焊接在軸肩上,鐵板有孔,與圓盤采用螺栓連接固定。因此,圓盤的設(shè)計(jì)也是釘齒滾筒強(qiáng)度高低的要部件。圓盤的材料采用剛度和強(qiáng)度較好的45鋼制成,其直徑,其上均勻分布著八個(gè)圓形形的通孔,目的是為了固定安裝釘齒條,其位置在圓盤上固定,長(zhǎng)方孔的底線距圓盤的中心為,其圓盤中心應(yīng)裝套在主軸的直徑上(),因此,圓盤的中心應(yīng)設(shè)定為的孔,以便安裝在軸上,圓盤的厚度選為,其上的圓形孔直徑10mm,同樣也是為了安裝其上的釘齒條。結(jié)構(gòu)設(shè)計(jì)如圖9所示: 圖9圓盤結(jié)構(gòu)圖 圖10.三維圖5 箱體 箱體的作用是提供一個(gè)封閉的摘果環(huán)境,并對(duì)相關(guān)部件起到支撐和定位的作用。 為了便于軸系部件的安裝和拆卸,將箱體做成剖分式,箱體由四周的端板組成,取軸的中心線所在的平面為剖分面。箱座和箱蓋采用普通螺栓連接,用圓柱銷定位。箱體的材料選用HT200,鑄造成型。6 機(jī)架 整個(gè)機(jī)架采用角鋼焊接而成,起到其他幾個(gè)部件的支撐、定位、連接作用,并將電機(jī)裝配在機(jī)架里面。摘果機(jī)安裝在機(jī)架上面,采用普通螺栓連接,具體結(jié)構(gòu)見(jiàn)裝配圖,如上圖10.7總結(jié) 畢業(yè)設(shè)計(jì)是我們從大學(xué)畢業(yè)生走向未來(lái)工程師的重要一步。此次設(shè)計(jì)從最初選題、開(kāi)題到計(jì)算、繪畫直到設(shè)計(jì)完成,其中需要綜合運(yùn)用這四年來(lái)我們所學(xué)到的專業(yè)知識(shí),分析并解決設(shè)計(jì)中遇到的問(wèn)題,是一次理論聯(lián)系實(shí)踐的訓(xùn)練,同時(shí)也進(jìn)一步鞏固、加深和拓展了我們所學(xué)的專業(yè)知識(shí),對(duì)于我們大學(xué)四年的學(xué)習(xí)起到了總結(jié)作用。通過(guò)這次的設(shè)計(jì)實(shí)踐,讓我逐步樹(shù)立了正確的設(shè)計(jì)理想,增強(qiáng)了創(chuàng)新意識(shí)熟悉并掌握了機(jī)械設(shè)計(jì)中的一般規(guī)律和方法,培養(yǎng)了我的分析問(wèn)題和解決問(wèn)題的能力。通過(guò)設(shè)計(jì)計(jì)算、繪圖及運(yùn)用技術(shù)標(biāo)準(zhǔn)、規(guī)范、設(shè)計(jì)手冊(cè)等有關(guān)設(shè)計(jì)資料,我進(jìn)行了較全面的機(jī)械設(shè)計(jì)基本技能訓(xùn)練。另外通過(guò)本次設(shè)計(jì)使我領(lǐng)悟出了機(jī)械設(shè)計(jì)的一般進(jìn)程:設(shè)計(jì)準(zhǔn)備、傳動(dòng)裝置總體設(shè)計(jì)、傳動(dòng)零件設(shè)計(jì)計(jì)算、裝配圖設(shè)計(jì)、零件工作圖設(shè)計(jì)、編寫設(shè)計(jì)說(shuō)明書。如果隨意打亂這個(gè)進(jìn)程,則難免會(huì)在設(shè)計(jì)中走彎路。同時(shí)在整個(gè)設(shè)計(jì)過(guò)程中,我們雖然要獨(dú)立完成,但是也要及時(shí)的與指導(dǎo)老師溝通和請(qǐng)教,避免在設(shè)計(jì)過(guò)程中走彎路。設(shè)計(jì)中的每一個(gè)環(huán)節(jié)都是相互關(guān)聯(lián)的,因此,每個(gè)環(huán)節(jié)完成后我們都要認(rèn)真檢查,對(duì)于任何一個(gè)錯(cuò)誤我們都不要放過(guò),認(rèn)真修改,精益求精。同時(shí)在每個(gè)零件設(shè)計(jì)時(shí)我們要注意它的結(jié)構(gòu)性、工藝性、經(jīng)濟(jì)型,要盡量采取標(biāo)準(zhǔn)件,在整體結(jié)構(gòu)設(shè)計(jì)出來(lái)時(shí)要對(duì)結(jié)構(gòu)進(jìn)行優(yōu)化,要對(duì)前階段設(shè)計(jì)中的不合理結(jié)構(gòu)尺寸進(jìn)行必要的修改,做到既經(jīng)濟(jì)又方便裝配。 畢業(yè)設(shè)計(jì)也暴露出自己許多的不足之處。比如缺乏綜合運(yùn)用專業(yè)知識(shí)的能力,對(duì)材料的不了解等等。這次實(shí)踐是對(duì)自己四年所學(xué)知識(shí)的一次大檢閱,使我明白自己知識(shí)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(zhǎng),以后更應(yīng)該在工作中學(xué)習(xí),努力使自己成為一個(gè)對(duì)社會(huì)有貢獻(xiàn)的人,為中國(guó)機(jī)械行業(yè)添上自己的微薄之力。8展望我國(guó)加入WTO以來(lái),國(guó)內(nèi)外關(guān)于花生摘果機(jī)械的開(kāi)發(fā)與推廣應(yīng)用日益增多,針對(duì)現(xiàn)有花生摘果機(jī)械存在的有點(diǎn)與不足,在未來(lái)的發(fā)展過(guò)程中,對(duì)花生摘果機(jī)械在生產(chǎn)應(yīng)用中的經(jīng)驗(yàn)進(jìn)行總結(jié),不斷完善其功能,使其呈現(xiàn)良好的發(fā)展勢(shì)頭。(1)提高機(jī)械摘果率、降低破損率 對(duì)花生摘果機(jī)械的關(guān)鍵技術(shù)與工作部件進(jìn)行重點(diǎn)攻關(guān),改革傳統(tǒng)結(jié)構(gòu),研究新的脫殼原理,優(yōu)化結(jié)構(gòu)設(shè)計(jì);同時(shí)在整體裝配上進(jìn)一步改進(jìn)和完善,提高摘果率,降低破損率。 (2)向自動(dòng)控制和自動(dòng)化方向發(fā)展大多數(shù)機(jī)具人共喂料和定位,影響了作業(yè)速度和作業(yè)質(zhì)量。因此應(yīng)通過(guò)機(jī)電一體化手段,開(kāi)發(fā)設(shè)計(jì)自動(dòng)喂料、自動(dòng)定位脫殼裝置,保證均勻喂料與有效定位,實(shí)現(xiàn)機(jī)組自動(dòng)化操作,進(jìn)一步提高作業(yè)精確性和作業(yè)速度,提高產(chǎn)品質(zhì)量與生產(chǎn)率,滿足部分大、中型加工企業(yè)的需要,以開(kāi)拓國(guó)內(nèi)外市場(chǎng)。新技術(shù)原理、新結(jié)構(gòu)材料、新工藝將不斷應(yīng)用于花生機(jī)械的研制開(kāi)發(fā)中,隨著液壓技術(shù)、電子技術(shù)、控制技術(shù)以及化工、冶金工業(yè)的發(fā)展,許多復(fù)雜的機(jī)械結(jié)構(gòu)、動(dòng)力傳遞、笨重的材料和落后的工藝將逐步被取代,減輕質(zhì)量、減小阻力,簡(jiǎn)化操作,減小輔助工作時(shí)間,延長(zhǎng)使用壽命,降低勞動(dòng)使用費(fèi)用等將作為主要涉及目標(biāo)應(yīng)用脫殼機(jī)械的設(shè)計(jì)制造。隨著國(guó)內(nèi)外高新技術(shù)的進(jìn)一步發(fā)展,如何將這些高新技術(shù)更好的應(yīng)用到實(shí)際生產(chǎn)中,也是目前花生脫殼機(jī)械需要盡快解決的問(wèn)題。參考文獻(xiàn)1尚書旗,王方艷,劉曙光,趙忠海,王建春;花生收獲機(jī)械的研究現(xiàn)狀與發(fā)展趨勢(shì)J;農(nóng)業(yè)工 報(bào);2004年01期.2濮良貴 紀(jì)名剛.機(jī)械設(shè)計(jì)M.北京:高等教育出版社.2005.3吳宗澤 羅勝國(guó).機(jī)械設(shè)計(jì)課程設(shè)計(jì)手冊(cè)M.北京:高等教育出版社.2006.4赴美花生機(jī)械考察組;關(guān)于赴美考察花生機(jī)械的報(bào)告J;花生學(xué)報(bào);1980年02期5王智才.我國(guó)農(nóng)機(jī)市場(chǎng)需求及發(fā)展前景J.農(nóng)機(jī)質(zhì)量與監(jiān)督 2002.(5):6-96張智猛,胡文廣,許婷婷,等中國(guó)花生生產(chǎn)的發(fā)展與優(yōu)勢(shì)分析J.花生學(xué)報(bào),2005.34(3):6-10.7王智才.我國(guó)農(nóng)機(jī)市場(chǎng)需求及發(fā)展前景J.農(nóng)機(jī)質(zhì)量與監(jiān)督 2002.(5):6-98陳書法,李耀明,孫星釗;花生聯(lián)合收獲機(jī)挖掘裝置的設(shè)計(jì)研究J;中國(guó)農(nóng)機(jī)化;2005年01期9余泳昌,劉文藝,馮春麗,謝華陽(yáng),丁攀;花生收獲機(jī)械發(fā)展與應(yīng)用現(xiàn)狀J;山東農(nóng)機(jī);2005年06期10胡志超;王海鷗;彭寶良;田立佳;計(jì)福來(lái);國(guó)內(nèi)外花生收獲機(jī)械化現(xiàn)狀與發(fā)展J;中國(guó)農(nóng)機(jī)化;2006年05期11程獻(xiàn)麗、高連興.花生沖擊脫殼的力學(xué)特性試驗(yàn)J. 沈陽(yáng)農(nóng)業(yè)大學(xué)學(xué)報(bào),2009(2):111-113.12尚書旗、劉曙光、王方艷等花生生產(chǎn)機(jī)械的研究現(xiàn)狀與進(jìn)展分析J農(nóng)業(yè)機(jī)械學(xué)報(bào),2005.(03):143-147systems. assessing the example of three tractors of the same category, which are exploited in climatic and soil conditions 1. Introduction for agricultural agricultural recognized careful technical, predicting ofcropproduction.Nowadays,theexistingmathematicaloptimiza- tion methods, supported by the high-performance computers, can efficiently resolve the optimization problems (Dette Duffy et al., 1994; Mileusnic, 2007; etc.). The formation of an optimal technical system in order to produce cheaper food, highly impacted reliability of tractors, its maintainability, and the functionality of the system. rounding conditions. Although in the same spirit, some authors have defined effectiveness somewhat differently. In (Ebramhimipour maintainabilityascapacityofthe systemforpreventionandfindingfailuresanddamages,forrenewing operating ability and functionality through technical attending and repairs; and functionality as the degree of fulfilling the functional requirements, namely the adjustment to environment, or more pre- cisely to the conditions in which the system operates. In the case of monitoring reliability and maintainability it is common to monitor the time picture of state (Fig. 1) according to their working conditions is obtained. The model can be used as cri- teria for decision making related to any procedure in purchasing, operation or maintenance of the system, for prediction of repair and maintenance costs. Quality and functionality of the proposed model is shown in effectiveness determination of agricultural machinery, precisely tractors. R. Miodragovic et al./Expert Systems with Applications 39 (2012) 89408946 8941 which the functions of reliability and maintainability can be deter- mined, as well as the mean time in operation and the mean time in failure. The main problem that occurs in forming the time picture of state is data monitoring and recording. In real conditions the ma- chines should be connected to information system which would precisely record each failure, duration and procedure of repair. This is usually expensive and improvised monitoring of the machine performance, namely of its shut downs, is imprecise. Moreover, statistical data processing provided by the time picture of the state requires that all machines work under equal conditions, which is difficult to achieve. As for the functionality of the technical system, there is no common way for its measuring and quantification. This is the reason why in this paper, in order to assess the effectiveness, expertise judgments of the employed in the working process of the analyzed machines will be used. Application of expertise judgments has been largely used in literature, primarily for data processing and the assessment of the technical systems in terms of: risk (Li Wang, Yang, Tanasijevic, Ivezic, Ignjatovic, Zadeh, 1996). Application of fuzzy sets today represents one of the most frequently used tools for solving the problems in various areas of optimization (Huang, Gu, Liebowitz, 1988) in general is also used for solving the optimizations problems from area of agro machinery. In article (Rohani, Abbaspour-Fard, and fuzzy composition of men- tioned indicators into one synthesized. Fuzzy proposition is pro- cedure for representing the statement that includes linguistic variables based on available information about considered techni- cal system. In that sense it is necessary to define the names of lin- guistic variables that represent different grades of effectiveness of considered technical system and define the fuzzy sets that describe the mentioned variables. Composition is a model that provides structure of indicators influences to the effectiveness performance. 2.1. Fuzzy model of problem solving The first step in the creation of fuzzy model for effectiveness (E) assessment is defining linguistic variables related to itself and to reliability (R), maintainability (M) and functionality (F). Regarding number of linguistic variables, it can be found that seven is the maximal number of rationally recognizable expressions that hu- man can simultaneously identify (Wang et al., 1995). However, for identification of considered characteristics even the smaller number of variables can be useful because flexibility of fuzzy sets to include transition phenomena as experts judgments commonly is (Ivezic et al., 2008). According to the above, five linguistic vari- ables for representing effectiveness performances are included: poor, adequate, average, good and excellent. Form of these linguis- tic variables is given as appropriate triangular fuzzy sets (Klir .;l 5 R ; l M l 1 M ; .;l 5 M ; l F l 1 F ; .;l 5 F 1 In the next step, maxmin composition is performed on them. Max min composition, also called pessimistic, is often used in fuzzy alge- bra as a synthesis model (Ivezic et al., 2008; Tanasijevic et al., 2011; Wang et al., 1995; Wang 2000). The idea is to make overall assess- ment (E) equal to the partial virtual representative assessment. This assessment is identified as the best possible one between the worst partial grades expected (R, M or F). It can be concluded that all elements of (R, M and F) that make the E have equal influence on E, so that maxmin composition will be used, which in parallel way treats the partial ones onto the h time of planned shut down due to preventive maintenance. 1995) and OR R M F If we tions that is (according to Fig. 2): with 39 (2012) 89408946 Further, for each outcome its values are calculated (X c ). The outcome which would suit the combination c, it would be calcu- lated following the equations: X c P R;M;E j hi c 3 3 Finally, all of these outcomes are treated with maxmin composi- tion, as follows: (i) For each outcome search for the MINimum value of l R,M,F in vector E c (2). The minimum which would suit the combina- tion o, it would be calculated following the equations: MIN 0 minfl j1;.;5 R ;l j1;.;5 M .;l j1;.;5 F g;for all o 1toO 4 (ii) Outcomes are grouped according to their values X c (3), namely the size of j. (iii) Find the MAXimum between previously identified mini- mums (i) for each group (ii) of outcomes. The maximum which would suit value of j, would be calculated following the equations: MAX j maxfMIN o g; for every j 5 E assessment of technical system is obtained in the form: l E This expression (Fig. 2 tion of to fuzzy cedure (d) between the E which d i E j ;H take into account only values if l j1;.;5 R;M;F 0, we get combina- are named outcomes (o =1toO, where O # C). in the process of synthesis, are also used. Precisely, if we look at three partial indicators, namely their membership function (1), it is possible to make C = j 3 =5 3 combina- tions of their membership functions. Each of these combinations represents one possible synthesis effectiveness assessment (E). E l j1;.;5 ;l j1;.;5 ; .;l j1;2;.5 hi ; for all c 1toC 2 maxmin compositions which by using operators AND provide an advantage to certain elements over the others synthetic indicator. In literature (Ivezic et al., 2008; Wang et al., Fig. 2. Effectiveness fuzzy sets. 8942 R. Miodragovic et al./Expert Systems MAX j1 ; .;MAX j5 l 1 E ; .;l 5 E 6 (6) is necessary to map back to the E fuzzy sets ). Best-fit (Wang et al., 1995), method is used for transforma- E description (6) to form that defines grade of membership sets: poor, adequate, average, good and excellent. This pro- is recognized as identification. Best-fit method uses distance E obtained by maxmin composition (6) and each of expressions (according to Fig. 2), to represent the degree to E is confirmed to each of fuzzy sets of effectiveness (Fig. 2). i X 5 j1 l j E C0l j H j 2 v u u t ; j 1; .;5;H i fexcellent;goodaverage;adequate;poorg7 E i fb i1 ;poor;b i2 ;adequate;b i3 ;good; b i4 ;average;b i5 ;excellentg 10 3. An illustrative example As an illustrative example of evaluation of agriculture machin- ery effectiveness, the comparative analysis of three tractors A 1 B 2 , and C 2 is given in this article. In tractor A a 7.146 l engine LO4V TCD 2013 is installed. Thanks to the reserves of torque from 35%, the tractor is able to meet all the requirements expected in the worst performing farming oper- ations in agriculture. Total tractor mass is 16,000 kg. According to OECD (CODE II) report maximum power measured at the PTO shaft is 243 kW at 2200 rpm with specific fuel consumption of 198 g/kW h (ECE-R24). Maximum engine torque is 1482 Nm at en- gine regime of 1450 rpm. Transmission gear is vario continious transmision. Linkage mechanism is a Category II/III with lifting force of 11,800 daN. In tractors B 2 and C 2 8.134 l engine 6081HRW37 JD is installed, with reserve torque of 40%, and this tractor was able to meet all the requirements expected in the worst performance of the farming operations in agriculture. Total tractor weight is 14,000 kg. Accord- ing to OECD (CODE II) report maximum power measured at the PTO shaft is 217 kW at 2002 rpm with specific fuel consumption of 193 g/kW h (ECE-R24). Maximum torque is 1320 Nm at engine revs of 1400 rpm. Transmission is AutoPower. Linkage mechanism is a Category II/III with lifting force of 10,790 daN. Both models have electronically controlled tractor engine and fuel supply system that meets the regulations on emissions. From the submitted technical characteristics of the tractor A, B and C it is seen that all three tractors are fully functional for l exc. = (0,0,0,0.25,1); l good = (0,0,0.25,1,0.25); l aver. = (0,0.25,1,0.25,0); l adeq. = (0.25,1,0.25,0,0); l poor = (1,0.25,0,0,0). The closer l E (6) is to the ith linguistic variable, the smaller d i is. Distance d i is equal to zero, if l E (6) is just the same as the ith expression in terms of the membership functions. In such a case, E should not be evaluated to other expressions at all, due to the exclusiveness of these expressions. Suppose d imin (i =1,.,5) is the smallest among the obtained distances for E j and leta 1 ,.,a 5 represent the reciprocals of the rel- ative distances (which is calculated as the ratio between corres- ponding distance d i (7) and the mentioned values d imin ). Then, a i can be defined as follows: a i 1 d i =d imin ; i 1; .;5 8 If d i = 0 it follows that a i = 1 and the others are equal to zero. Then, a i can be normalized by: b i a j P 5 m1 a im ; i 1; .;5 X 5 i1 b i 1 9 Each b i represents the extent to which E belongs to the ith defined E expressions. It can be noted that if E i completely belongs to the ith expression then b i is equal to 1 and the others are equal to 0. Thus b j could be viewed as a degree of confidence that E i belongs to the ith E expressions. Final expression for E performance at the level of tech- nical system, have been obtained in the form (10) where Applications 1 Tractor Fendt Vario 936. 2 Tractor John Deere 8520. performing difficult operations for different technologies of agri- cultural production. Tractors B and C have the same technical char- acteristics, and practice is the same type and model, except that the tractor B entered into operation in May 2007, a tractor C in June 2007. A tractor on the experimental farm, which is the technical documentation for the base model, comes into operation in July 2009. The main task of maintaining agricultural techniques is to provide functionality and reliability of machines. Maintenance of all three tractors is done by machine shop owned by the user up- grade option. Ten engineers (analysts) working on maintenance and opera- tion of tractors were interviewed. Their evaluation of R, D and F are given in Table 1. First, the effectiveness of tractor A is calculated. It can be seen that the reliability was assessed as excellent by six out of ten ana- lysts (6/10 = 0.6), as average by three (0.3) and as good by one (0.1). In this way the assessment R is obtained in the form (11): R 0:6=exc; 0:3=good; 0:1=aver; 0=adeq; 0=poor11 In the same way the assessments for M and F are obtained: M 0:4=exc; 0:4=good; 0:2=aver; 0=adeq; 0=poor F 0:5=exc; 0:5=good; 0=aver; 0=adeq; 0=poor In the next step, these assessments are mapped on fuzzy sets (Fig. 1) in order to obtain assessment in the form (1). For example, Reliabil- ity in this example is determined as (11), where it is to linguistic variable excellent joined weight 0.6. Thereby, fuzzy set excellent is defined as: R exc = (1/0, 2/0, 3/0, 4/0.25, 5/1.0) (according to Fig. 1). In this way the specific values of fuzzy set excellent R exc0.6 = (1/(0 C2 0.6), 2/(0 C2 0.6), 3/(0 C2 0.6), 4/(0.25 C2 0.6), 5/(1.0 C2 0.6) are obtained. The remaining four linguistic variables are treated in the same way. In the end for each j =1,.,5 specific membership functions (last row, Table 2) are added into the final fuzzy form (1) of tractor A reliability: l RA 0;0:025;0:175;0:475;0:675 In the same way, based on the questionnaire (Table 1) values for maintainability and functionality are obtained: l MA 0;0:05;0:3;0:55;0:5; l FA 0;0;0:125;0:625;0:62512 These fuzzificated assessments (11) and (12) are necessary to syn- thesize into assessment of effectiveness, using maxmin logics. In this case it is possible to make C =5 3 = 125 combinations, out of which the 48 outcomes. First outcome would be for combination 2-2-3: E 2-2-3 = 0.025,0.05,0.125, where is X 2-2-3 = (2 + 2 + 3)/3 = 2 (rounded as integer). Smallest value among the membership func- tions of this outcome is 0.025. Other outcomes and corresponding values of X c are shown in Table 3. All these outcomes can be grouped around sizes X = 2, 3, 4 and 5. For example, for outcome X = 5 it can be written: E 4C05C05 0:475;0:5;0:625C138;E 5C04C05 0:675;0:55;0:625C138;E 5C05C04 0:675;0:5;0:625C138;E 5C05C05 0:675;0:5;0:625C138 Further, for each of them, minimum between membership function is sought: Table 1 Results of questionnaire. Average x x xx x xx x R. Miodragovic et al./Expert Systems with Applications 39 (2012) 89408946 8943 Analyst Linguistic variables Tractor A Tractor B Excellent Good Average Adequate Poor Excellent Good 1R x x Mx x Fxxx 2R x Mx x Fx 3R x x Mx Fx 4R x x Mx Fx x 5R x x Mx Fxxx 6R x x Mx Fx x 7R x Mx Fx 8R x x Mx x Fx x 9R x x Mx x Fx x 10 R x x Mx x Fx x Tractor C Adequate Poor Excellent Good Average Adequate Poor x x x x x x x x x x x xx x x x x x x x x x with Table 2 Calculation of specific values of fuzzy sets. 12345 0.6/exc. 0 C2 0.6 0 C2 0.6 0 C2 0.6 0.25 C2 0.6 1.0 C2 0.6 0.3/good 0 C2 0.3 0 C2 0.3 0.25 C2 0.3 1.0 C2 0.3 0.25 C2 0.3 8944 R. Miodragovic et al./Expert Systems MINE 4C05C05 minf0:475;0:5;0:625g0:475;MINE 5C04C05 0:55;MINE 5C05C04 0:5;MINE 5C05C05 0:5 Between these minimums, in the end it seeks maximum: MAXX d5 maxf0:475;0:55;0:5;0:5g0:55 Also for other values: X: MAX X =2 = 0.025; MAX X =3 = 0.175; MAX X =4 = 0.55 (Table 1.) 0.1/aver. 0 C2 0.1 0.25 C2 0.1 1.0 C2 0.1 0.25 C2 0.1 0 C2 0.1 0/adeq. 0.25 C2 0 1.0 C2 0 0.25 C2 00C2 00C2 0 0/poor 1.0 C2 0 0.25 C2 00C2 C2 C2 0 P R 0 0.025 0.175 0.475 0.675 Table 3 Structure of MAXMIN composition. Comb. X l MIN 2345 2-2-3 2 0.025,0.05,0.125 0.025 2-2-4 3 0.025,0.05,0.625 0.025 2-2-5 3 0.025,0.05,0.625 0.025 2-3-3 3 0.025,0.3,0.125 0.025 2-3-4 3 0.025,0.3,0.625 0.025 2-3-5 3 0.025,0.3,0.625 0.025 2-4-3 3 0.025,0.55,0.125 0.025 2-4-4 3 0.025,0.55,0.625 0.025 2-4-5 4 0.025,0.55,0.625 0.025 2-5-3 3 0.025,0.5,0.125 0.025 2-5-4 4 0.025,0.5,0.625 0.025 2-5-5 4 0.025,0.5,0.625 0.025 3-2-3 3 0.175,0.05,0.125 0.05 3-2-4 3 0.175,0.05,0.625 0.05 3-2-5 3 0.175,0.05,0.625 0.05 3-3-3 3 0.175,0.3,0.125 0.125 3-3-4 3 0.175,0.3,0.625 0.175 3-3-5 4 0.175,0.3,0.625 0 0.175 3-4-3 3 0.175,0.55,0.125 0.125 3-4-4 4 0.175,0.55,0.625 0.175 3-4-5 4 0.175,0.55,0.625 0.175 3-5-3 4 0.175,0.5,0.125 0.125 3-5-4 4 0.175,0.5,0.625 0.175 3-5-5 4 0.175,0.5,0.625 0.175 4-2-3 3 0.475,0.05,0.125 0.05 4-2-4 3 0.475,0.05,0.625 0.05 4-2-5 4 0.475,0.05,0.625 0.05 4-3-3 3 0.475,0.3,0.125 0.125 4-3-4 4 0.475,0.3,0.625 0.3 4-3-5 4 0.475,0.3,0.625 0.3 4-4-3 4 0.475,0.55,0.125 0.125 4-4-4 4 0.475,0.55,0.625 0.475 4-4-5 4 0.475,0.55,0.625 0.475 4-5-3 4 0.475,0.5,0.125 0.125 4-5-4 4 0.475,0.5,0.625 0.475 4-5-5 5 0.475,0.5,0.625 0.475 5-2-3 3 0.675,0.05,0.125 0.05 5-2-4 4 0.675,0.05,0.625 0.05 5-2-5 4 0.675,0.05,0.625 0.05 5-3-3 4 0.675,0.3,0.125 0.125 5-3-4 4 0.675,0.3,0.625 0.3 5-3-5 4 0.675,0.3,0.625 0.3 5-4-3 4 0.675,0.55,0.125 0.125 5-4-4 4 0.675,0.55,0.625 0.55 5-4-5 5 0.675,0.55,0.625 0.55 5-5-3 4 0.675,0.5,0.125 0.125 5-5-4 5 0.675,0.5,0.625 0.5 5-5-5 5 0.675,0.5,0.625 0.5 MAX 0.025 0.175 0.55 0.55 Finally, we get expression for membership function of effective- ness of tractor A: l EA 0;0:025;0:175;0:55;0:55 Best-fit method (79) and proposed E fuzzy set (Fig. 1) give the final effectiveness assessment for the tractor A: d 1 E;exc X 5 j1 l j E C0l j exc 2 v u u t 0C00 2 0:025C00 2 0:175C00 2 0:55C00:25 2 0:55C01 2 q 0:56899 where is : l E 0;0:025;0:175;0:55;0:55 l exc 0;0;0;0:25;1 For other fuzzy sets: d 2 (E, good) = 0.54658, d 3 (E, aver) = 1.06007, d 4 (E, adeq) = 1.27426, d 5 (E, poor) = 1.29856. for d min d 2 : a 1 1 d 1 =d 2 1 0:56899=0:54658 0:96061; a 2 1:00000;a 3 0:51561;a 4 0:42894;a 5 0:42091: b 1 a 1 P 5 i1 a i 0:96901 0:96901 1 0:51561 0:42894 0:42091 0:28881; b 2 0:30065;b 3 0:15502;b 4 0:12896;b 5 0:12655: Finally, we get the assessment of effectiveness of tractor A, in form (10): E A =(b 1 , excellent), (b 2 , good), (b 3 , average), (b 4 , ade- quate), (b 5 , poor) = (0.28881, excellent), (0.30065, good), (0.15502, average), (0.12896, adequate), (0.12655, poor) In the same way, we get the assessments for other two tractors B and C: E B = (0.23793, excellent), (0.27538, good), (0.20635, aver- age), (0.14693, adequate), (0.13342, poor) E C = (0.17507, excellent), (0.25092, good), (0.25468, aver- age), (0.17633, adequate), (0.14300, poor). Tractor A is in great extent of 0.30065 (in relation to 30 %) as- sessed as good, tractor B in great extent of 0.27538 (27.5%) as- Applications 39 (2012) 89408946 sessed as good, while tractor C is in great extent of 0.25468 (25.5%) assessed as average. It can be concluded that C is the worst, while tractor A is only somewhat better than B, especially if we see with that A is assessed as excellent in the extent of 28.8% while B in the extent of 23.8%. Effectiveness of analyzed tractors can be presented as in Fig. 3., where it can be more clearly seen that tractor A has the biggest effectiveness. If this assessment (E A , E B , E C ) is defuzzificated by center of mass point calculation Z (Bowles if calculated on 10,000 moto-hours, Fig. 3. Relationship of effectiveness of observed tractors. R. Miodragovic et al./Expert Systems it would spend in work 9244 moto-hours. As of the tractor B, out of 10,004 available moto-hours, it spent 9069 moto-hours in work, and tractor C out of 9981 available moto-hours spent 9045 in work. The experiment showed that the more reliable and efficient tractors are the less frequent are delays. In part, this initial advan- tage wiped out worse logistics of delivery of spare parts when it comes to tractor A. in 1100 moto-hours work of the tractor, due to poor logistics in maintaining hoped to eight working days, and it greatly influenced the decline in benefits of maintainability of a given tractor and thus the decline in total exploitation of the same efficiency (Internal technical documentation PKB). 4. Conclusion This paper presents a model for effectiveness assessment of technical systems, precisely agricultural machinery, based on fuzzy sets theory. Effectiveness performance has been adopted as overall indicator of systems quality of service, i.e. as entire measure of technical system availability. Reliability, maintainability and func- tionality performances have been recognized as effectiveness parameters or indicators. Linguistic form can be appointed as the References Bowles, J. B., & Pelaez, C. E. (1995). Fuzzy logic prioritization of failures in a system failure mode, effects and criticality analysis. Reliability Engineering and System Safety, 50(2), 203213. Cai, K. Y. (1996).
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