喜歡這套資料就充值下載吧。。。資源目錄里展示的都可在線預(yù)覽哦。。。下載后都有,,請(qǐng)放心下載,,文件全都包含在內(nèi),,【有疑問咨詢QQ:414951605 或 1304139763】
=============================================
喜歡這套資料就充值下載吧。。。資源目錄里展示的都可在線預(yù)覽哦。。。下載后都有,,請(qǐng)放心下載,,文件全都包含在內(nèi),,【有疑問咨詢QQ:414951605 或 1304139763】
=============================================
編號(hào)
無錫太湖學(xué)院
畢業(yè)設(shè)計(jì)(論文)
題目: 無軸攪拌機(jī)傳動(dòng)系統(tǒng)的設(shè)計(jì)
信機(jī) 系 機(jī)械工程及自動(dòng)化 專業(yè)
學(xué) 號(hào): 0923829
學(xué)生姓名: 龍 躍
指導(dǎo)教師: 韓邦華 (職稱:副教授)
(職稱: )
2013年5月25日
I
無錫太湖學(xué)院本科畢業(yè)設(shè)計(jì)(論文)
誠 信 承 諾 書
本人鄭重聲明:所呈交的畢業(yè)設(shè)計(jì)(論文)無軸攪拌機(jī)傳動(dòng)系統(tǒng)的設(shè)計(jì)是本人在導(dǎo)師的指導(dǎo)下獨(dú)立進(jìn)行研究所取得的成果,其內(nèi)容除了在畢業(yè)設(shè)計(jì)(論文)中特別加以標(biāo)注引用,表示致謝的內(nèi)容外,本畢業(yè)設(shè)計(jì)(論文)不包含任何其他個(gè)人、集體已發(fā)表或撰寫的成果作品。
班 級(jí): 機(jī)械97
學(xué) 號(hào): 0923829
作者姓名:
2013 年 5 月 25
無錫太湖學(xué)院
畢業(yè)設(shè)計(jì)(論文)
開題報(bào)告
題目: 無軸攪拌機(jī)傳動(dòng)系統(tǒng)的設(shè)計(jì)
信 機(jī) 系 機(jī)械工程及自動(dòng)化 專業(yè)
學(xué) 號(hào): 0923829
學(xué)生姓名: 龍躍
指導(dǎo)教師: 韓邦華 (職稱:副教授 )
(職稱: )
2012年 11 月25日
課題來源
參考現(xiàn)場(chǎng)實(shí)際生產(chǎn),結(jié)合畢業(yè)設(shè)計(jì)要求,與指導(dǎo)老師商量后決定的。
科學(xué)依據(jù)(包括課題的科學(xué)意義、研究現(xiàn)狀等)
(一)科學(xué)意義:
改革開放30年來,中國混凝土攪拌機(jī)市場(chǎng)從無到有,從小到大。但我國混凝土攪拌技術(shù)相對(duì)落后,具有自主知識(shí)產(chǎn)權(quán)的技術(shù)很少。隨著近年來商品混凝土的大力推廣以及工程建設(shè)施工的高效率化、高質(zhì)量化和高效益化,客觀上推動(dòng)了混凝土攪拌設(shè)備向高效率、高質(zhì)量方向發(fā)展。此外,從市場(chǎng)需求看,用戶對(duì)施工質(zhì)量和效率的要求也越來越高,一些傳統(tǒng)產(chǎn)品己無法滿足越來越高的施工要求。
在現(xiàn)有雙臥軸攪拌機(jī)的基礎(chǔ)上,開發(fā)適合我國國情、發(fā)展?jié)摿^大的新型攪拌機(jī)迫在眉睫。一方面,通過新型攪拌設(shè)備的開發(fā)、新技術(shù)的探討和創(chuàng)新,提高混凝土授拌設(shè)備的設(shè)計(jì)和技術(shù)水平,并帶動(dòng)相關(guān)技術(shù)發(fā)展,創(chuàng)造良好的社會(huì)效益;另一方面,通過高效混凝土攪拌設(shè)備的研究,推動(dòng)攪拌設(shè)備性能的全面提高,推出適應(yīng)市場(chǎng)要求、具有更高可靠性和較強(qiáng)競(jìng)爭(zhēng)力的產(chǎn)品,獲得更好的經(jīng)濟(jì)效益。依據(jù)新的攪拌理論,采用理論分析和試驗(yàn)研究相結(jié)合的方法,較好地解決了大型雙臥軸攪拌機(jī)存在的低效區(qū)問題,如果工業(yè)化成功并得到廣泛的應(yīng)用,一定為研制具有自主知識(shí)產(chǎn)權(quán)的高效攪拌設(shè)備做出重大貢獻(xiàn),將具有良好的經(jīng)濟(jì)和社會(huì)效益。
(二)研究現(xiàn)狀:
長期以來,國內(nèi)外攪拌機(jī)雖然種類繁多,但他們的共同特點(diǎn)就是有一根軸貫穿整個(gè)攪拌空間。
“雙螺旋軸攪拌機(jī)”是一種新型的“無軸”攪拌機(jī),其葉片形狀如圖所示。它具有雙倍的徑向料流,雙倍的軸向料流,雙倍的剪切,使器其攪拌效率是普通雙臥軸攪拌機(jī)兩倍,能耗更小。“雙螺旋軸攪拌機(jī)”無水平橫臥的主軸,不會(huì)產(chǎn)生混凝土骨料黏合中心軸上結(jié)塊形成抱軸現(xiàn)象,利于加工粘性較強(qiáng)和添加有纖維的特種混凝土材料。無攪拌臂的阻礙,使其空間更大。 但是僅對(duì)其攪拌部分進(jìn)行的改進(jìn)還是不能達(dá)到真正的提高效率、節(jié)約能源的效果,所以我們?cè)趯?duì)一些公司、工廠進(jìn)行調(diào)研后,對(duì)其傳動(dòng)部件進(jìn)行深入研究確定了最初方案,對(duì)機(jī)器進(jìn)行改良,并達(dá)到理想效果。
研究內(nèi)容
通過實(shí)際調(diào)研和采集相應(yīng)的設(shè)計(jì)數(shù)據(jù),分析攪拌機(jī)工作過程中的驅(qū)動(dòng)等方面的相關(guān)數(shù)據(jù),結(jié)合傳動(dòng)的相關(guān)理論知識(shí),完成無軸傳動(dòng)方案分析和擬定,并進(jìn)行主要功能元件的設(shè)計(jì)與選擇及傳動(dòng)系統(tǒng)的驗(yàn)算校核等。
擬采取的技術(shù)路線
通過實(shí)踐與大量搜集、閱讀相關(guān)資料,以及在跟老師進(jìn)行商討研究后,我們采用的技術(shù)路線是:①現(xiàn)場(chǎng)調(diào)研,收集資料②擬定最初方案,總體設(shè)計(jì)草圖③部件設(shè)計(jì)草圖④部件圖的完成⑤裝配圖的完成⑥英文翻譯和說明書的完成⑦最終的裝訂
研究計(jì)劃及預(yù)期成果
現(xiàn)場(chǎng)調(diào)研、模擬、建模、實(shí)驗(yàn)、機(jī)器調(diào)試,達(dá)到產(chǎn)品的最優(yōu)化設(shè)計(jì),大大降低勞動(dòng)強(qiáng)度和提高生產(chǎn)效率。
特色或創(chuàng)新之處
適用于現(xiàn)代加工企業(yè)高效、安全的無軸傳動(dòng)設(shè)計(jì)、傳動(dòng)裝置的優(yōu)化設(shè)計(jì),可降低工人的勞動(dòng)強(qiáng)度、減少機(jī)械加工工藝時(shí)間和降低機(jī)械零件的生產(chǎn)成本、提高效率就、節(jié)約能源等效果。
已具備的條件和尚需解決的問題
針對(duì)實(shí)際使用過程中存在的傳動(dòng)設(shè)計(jì)問題,綜合所學(xué)的機(jī)械理原理、機(jī)械設(shè)計(jì)以及機(jī)電傳動(dòng)等方面的知識(shí),實(shí)現(xiàn)適合于現(xiàn)代加工制造業(yè)、無軸傳動(dòng)裝置的優(yōu)化設(shè)計(jì),進(jìn)而提高學(xué)生開發(fā)和創(chuàng)新機(jī)械產(chǎn)品的能力。
指導(dǎo)教師意見
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
摘 要 本次畢業(yè)設(shè)計(jì)的題目為無軸攪拌機(jī)傳動(dòng)部件的設(shè)計(jì)。首先對(duì)傳統(tǒng)的幾種常見的攪拌 機(jī)構(gòu)進(jìn)行分析、總結(jié)其工作原理及其存在的常見問題。了解目前對(duì)其存在的問題的常用 解決方案。熟悉“無軸”攪拌理念,掌握無軸攪拌機(jī)的工作原理,然后將其與傳統(tǒng)的攪 拌機(jī)進(jìn)行比較,分析其主要優(yōu)點(diǎn)及可能存在的問題以及解決方案。 其次,這次設(shè)計(jì)的重點(diǎn)是對(duì)其傳動(dòng)部件的設(shè)計(jì)計(jì)算,我采用的是帶輪加錐齒輪的減 速機(jī)構(gòu),即利用了帶輪的傳動(dòng)遠(yuǎn)距離傳動(dòng)、大傳動(dòng)比,又利用了錐齒輪傳動(dòng)可改變傳動(dòng) 方向的優(yōu)點(diǎn)。通過設(shè)計(jì)計(jì)算達(dá)到了即提高工作效率又能有效地節(jié)約能源的目的。 關(guān)鍵詞: 無軸攪拌機(jī) ;傳動(dòng)部件 ;攪拌機(jī)構(gòu) I Abstract The graduation project is the subject of non-transmission parts mixer shaft design. First of all, the traditional institutions in several common mixing analysis, concluding its work principle and the existence of the frequently asked questions. Understand the current problems of its common solutions. Familiar with the non-axis mixing the concept of master-axis mixer without the working principle, and the mixer with the traditional comparison, analysis of their main advantages and potential problems and solutions. Secondly, this is designed to focus on the design of its drive components, I used the bevel gear pulley increases the speed, namely the use of long-distance transmission of drive pulley, the transmission ratio and the use of a bevel gear transmission can change the direction of the advantages of transmission. Achieved through the design of computing that can effectively improve the efficiency and energy savings. Key words: No shaft mixer;Transmission parts ;Stir agencies II 目 錄 摘 要 .III Abstract.IV 目 錄 .V 1 緒論.1 1.1 無軸式攪拌機(jī)研究發(fā)展現(xiàn)狀.1 1.2 攪拌機(jī)的各種類型及特點(diǎn).2 1.3 無軸式攪拌機(jī)特點(diǎn).3 1.4 攪拌機(jī)的分析及設(shè)計(jì)任務(wù).3 1.4.1 攪拌機(jī)常見問題的原因分析.3 1.4.2 無軸攪拌的理念.4 1.4.3 基本設(shè)計(jì)任務(wù).5 1.4.4 畢業(yè)設(shè)計(jì)的目的.5 1.5 課題研究背景及意義.5 1.5.1 課題研究背景.5 1.5.2 課題研究意義.5 2 傳動(dòng)方案及電動(dòng)機(jī)的選擇.7 2.1 傳動(dòng)方案的選擇.7 2.2 電動(dòng)機(jī)選擇.8 3 傳動(dòng)比的計(jì)算與分配.9 3.1 計(jì)算總傳動(dòng)比.9 3.2 傳動(dòng)比的分配.9 4 傳動(dòng)運(yùn)動(dòng)參數(shù)的計(jì)算.11 4.1 各級(jí)轉(zhuǎn)速.11 4.2 各級(jí)的輸入功率.11 4.3 各級(jí)轉(zhuǎn)矩.11 5 V 帶輪傳動(dòng)的設(shè)計(jì)計(jì)算 .13 5.1 設(shè)計(jì)準(zhǔn)則.13 5.2 原始數(shù)據(jù)及設(shè)計(jì)內(nèi)容.13 5.2.1 原始數(shù)據(jù):.13 5.2.2 設(shè)計(jì)內(nèi)容:.13 5.3 設(shè)計(jì)步驟和方法.13 5.3.1 確定計(jì)算功率 .13caP 5.3.2 選擇帶型.13 5.3.3 確定帶輪的基準(zhǔn)直徑 和 .131d2 5.3.4 確定中心距和帶輪的基準(zhǔn)長度 .14dL III 5.3.5 驗(yàn)算主動(dòng)輪上的包角 .141 5.3.6 單根 V 帶傳遞的額定功率 .15 5.3.7 確定帶的根數(shù) Z .15 5.3.8 確定帶的預(yù)緊力 .150F 6 V 帶輪設(shè)計(jì) .17 6.1 V 帶輪的設(shè)計(jì)內(nèi)容 .17 6.2 設(shè)計(jì)要求.17 6.3 帶輪材料的選擇及結(jié)構(gòu)形式.17 6.3.1 材料的選擇.17 6.3.2 結(jié)構(gòu)形式.17 6.4 V 帶輪的輪槽 .17 6.5 V 帶輪傳動(dòng)的張緊 .18 7 錐齒輪傳動(dòng)的設(shè)計(jì)計(jì)算.19 7.1. 選定精度等級(jí),材料及齒數(shù) .19 7.1.1 齒輪精度等級(jí)的選擇.19 7.1.2 材料選擇.19 7.1.3 齒數(shù)選擇.19 7.2 按齒面接觸強(qiáng)度設(shè)計(jì).19 7.2.1 確定公式內(nèi)的各計(jì)算數(shù)值.20 7.2.2 計(jì)算.20 7.3 按齒根彎曲強(qiáng)度設(shè)計(jì).21 7.3.1 確定公式內(nèi)的各計(jì)算數(shù)值.21 7.4 幾何尺寸計(jì)算.22 7.4.1 計(jì)算分度圓直徑.22 7.4.2 錐距.22 7.4.3 計(jì)算齒輪寬度.22 7.4.4 錐齒輪的結(jié)構(gòu)設(shè)計(jì).22 8 軸的設(shè)計(jì)計(jì)算.25 8.1 I 軸的設(shè)計(jì)計(jì)算(錐齒輪軸) .25 8.1.1 材料.25 8.1.2 初定軸的最小直徑.25 8.1.3 根據(jù)軸定位的要求確定軸的各段直徑和長度.25 8.1.4 小錐齒輪的受力分析.26 8.1.5 鍵的校核.26 8.1.6 I 軸軸承的校核 .26 8.1.7 軸上載荷的計(jì)算.28 8.1.8 按彎扭合成應(yīng)力校核軸的強(qiáng)度.29 IV 8.2 II 軸的設(shè)計(jì)計(jì)算 .29 8.2.1 材料.29 8.2.2 初定最小直徑.29 8.2.3 聯(lián)軸器的選擇.29 8.2.4 根據(jù)軸的定位要求,確定各段直徑和長度.30 8.2.5 大錐齒輪軸的受力分析.30 8.2.6 鍵的校核.30 8.2.7 軸承的校核.30 8.2.8 軸上載荷的計(jì)算.32 8.2.9 按彎扭合成應(yīng)力校核軸的強(qiáng)度.33 9 結(jié)論與展望.35 致謝.37 參考文獻(xiàn).39編號(hào)
無錫太湖學(xué)院
畢業(yè)設(shè)計(jì)(論文)
相關(guān)資料
題目: 無軸攪拌機(jī)傳動(dòng)系統(tǒng)的設(shè)計(jì)
信機(jī) 系 機(jī)械工程及自動(dòng)化專業(yè)
學(xué) 號(hào): 0923829
學(xué)生姓名: 龍 躍
指導(dǎo)教師: 韓邦華 (職稱:副教授 )
(職稱: )
2013年5月25日
目 錄
一、畢業(yè)設(shè)計(jì)(論文)開題報(bào)告
二、畢業(yè)設(shè)計(jì)(論文)外文資料翻譯及原文
三、學(xué)生“畢業(yè)論文(論文)計(jì)劃、進(jìn)度、檢查及落實(shí)表”
四、實(shí)習(xí)鑒定表
存檔編碼:無無錫錫太太湖湖學(xué)學(xué)院院 2013 屆屆畢畢業(yè)業(yè)作作業(yè)業(yè)周周次次進(jìn)進(jìn)度度計(jì)計(jì)劃劃、檢檢查查落落實(shí)實(shí)表表 系別:信機(jī)系 班級(jí):機(jī)械97 學(xué)生姓名:龍躍 課題(設(shè)計(jì))名稱:無軸攪拌機(jī)傳動(dòng)系統(tǒng)的設(shè)計(jì) 開始日期:2012年11月12日周次起止日期工作計(jì)劃、進(jìn)度每周主要完成內(nèi)容存在問題、改進(jìn)方法指導(dǎo)教師意見并簽字備 注1-32012年11月12日-2012年12月2日下達(dá)畢業(yè)設(shè)計(jì)任務(wù)實(shí)習(xí)實(shí)訓(xùn),參與工作存在問題:對(duì)于實(shí)際操作不是很了解改進(jìn)方法:參與工作,逐漸了解,參與其中4-102012年12月3日-2013年1月20日填寫畢業(yè)設(shè)計(jì)開題報(bào)告填寫畢業(yè)設(shè)計(jì)開題報(bào)告存在問題:對(duì)課題難易程度理解不夠,難點(diǎn)分析不足,分析能力欠缺,許多問題不是很明白改進(jìn)方法:在指導(dǎo)老師的幫助下,進(jìn)一步消化本課題。11-122013年1月21日-3月1日檢查畢業(yè)設(shè)計(jì)準(zhǔn)備情況修改完善畢業(yè)設(shè)計(jì)開題報(bào)告存在問題:對(duì)課題難點(diǎn)分析不足,分析能力欠缺,對(duì)課題理解不深,頭腦里沒設(shè)計(jì)的東西的概念改進(jìn)方法:在指導(dǎo)老師的幫助下,整改開題報(bào)告132013年3月4日-3月8日查閱參考資料查閱與設(shè)計(jì)有關(guān)的參考資料不少于10本,其中外文不少于2本存在問題:由于工作原因,空閑時(shí)間很少,查閱資料太少。改進(jìn)方法:利用一切時(shí)間,去圖書館和網(wǎng)上查找相關(guān)資料142013年3月11日-3月15日確定工作機(jī)構(gòu)和傳動(dòng)系統(tǒng)的運(yùn)動(dòng)方案擬定工作機(jī)構(gòu)和傳動(dòng)系統(tǒng)的運(yùn)動(dòng)方案,并進(jìn)行多方案對(duì)比分析存在問題:缺乏實(shí)際操作經(jīng)驗(yàn),制定的工藝方案不合理改進(jìn)方法:多去咨詢師傅了解實(shí)際生產(chǎn)過程,重新確立合理的工藝方案152013年3月18日-3月22日對(duì)無軸攪拌機(jī)傳動(dòng)系統(tǒng)具有初步分析能力和改進(jìn)設(shè)計(jì)的能力確定傳動(dòng)系統(tǒng)結(jié)構(gòu),計(jì)算所需各種尺寸存在問題:傳動(dòng)結(jié)構(gòu)設(shè)計(jì)不合理,尺寸計(jì)算有誤差公式運(yùn)用錯(cuò)誤。對(duì)傳動(dòng)設(shè)計(jì)數(shù)據(jù)不了解改進(jìn)方法:查閱多種參考資料,改進(jìn)傳動(dòng)結(jié)構(gòu),提高計(jì)算正確率162013年3月25日-3月29日理論聯(lián)系實(shí)際的工作方法和獨(dú)立工作能力深化和提高分析產(chǎn)品圖、分析傳動(dòng)機(jī)構(gòu)存在問題:缺乏生產(chǎn)經(jīng)驗(yàn),對(duì)傳動(dòng)機(jī)構(gòu)不了解,對(duì)傳動(dòng)安排不合理改進(jìn)方法:多了解實(shí)際生產(chǎn)過程,重新確立合理的方案172013年4月1日-4月5日裝配圖初步繪制傳動(dòng)系統(tǒng)裝配圖存在問題:對(duì)CAD運(yùn)用不熟悉,畫圖速度較慢改進(jìn)方法:重新確定合理的表達(dá)視圖,多加運(yùn)用繪圖軟件,提高畫圖速度182013年4月8日-4月12日裝配圖修改傳動(dòng)裝配圖存在問題:2D裝配圖中部分標(biāo)準(zhǔn)件畫法不正確,尺寸不精確。改進(jìn)方法:按機(jī)械制圖要求改正不正確的畫法,修改尺寸192013年4月15日-4月19日完成零件圖修改傳動(dòng)裝配圖和零件圖存在問題:2D裝配圖中技術(shù)要求填寫不合理,明細(xì)欄填寫不正確。改進(jìn)方法:按機(jī)械制圖要求改正不當(dāng)之處202013年4月22日-4月26日詳細(xì)審閱設(shè)計(jì)計(jì)算、說明書及圖紙并修改按學(xué)校畢業(yè)設(shè)計(jì)論文格式要求,再次檢查論文及圖紙并修改各個(gè)部分的格式要求,通過學(xué)校給的格式模板解決212013年4月29日-5月5日遞交初稿按學(xué)校畢業(yè)設(shè)計(jì)論文裝訂要求,進(jìn)行所有材料的整理資料順序不對(duì),需對(duì)照要求核查,進(jìn)行裝訂222013年5月6日-5月10日修改畢業(yè)論文按指導(dǎo)老師的批注,修改畢業(yè)論文論文中有許多細(xì)節(jié)的地方?jīng)]有注意到,經(jīng)老師批注后給予改正232013年5月13日-5月25日遞交畢業(yè)設(shè)計(jì)資料,準(zhǔn)備答辯材料2425 說明:1、“工作計(jì)劃、進(jìn)度”、“指導(dǎo)教師意見并簽字”由指導(dǎo)教師填寫,“每周主要完成內(nèi)容”,“存在問題、改進(jìn)方法”由學(xué)生填寫。2、本表由各系妥善歸檔,保存?zhèn)洳?。周次起止日期工作?jì)劃、進(jìn)度每周主要完成內(nèi)容存在問題、改進(jìn)方法指導(dǎo)教師意見并簽字備 注
無錫太湖學(xué)院
信 機(jī) 系 機(jī)械工程及自動(dòng)化 專業(yè)
一、 題目及專題
1、 題目 無軸攪拌機(jī)傳動(dòng)系統(tǒng)的設(shè)計(jì)
2、 專題
二、 課題來源及選題依據(jù)
參考現(xiàn)場(chǎng)實(shí)際生產(chǎn),要求學(xué)生能夠結(jié)合無軸攪拌機(jī)的工作原理和過程,針對(duì)實(shí)際使用過程中存在的攪拌阻力、攪拌空間、能耗等問題,綜合所學(xué)的機(jī)械原理、機(jī)械設(shè)計(jì)以及機(jī)電傳動(dòng)等知識(shí),對(duì)攪拌機(jī)的無軸工作進(jìn)行改進(jìn)設(shè)計(jì),使其在工作過程中真正達(dá)到提高效率,節(jié)約能源的效果。
改進(jìn)過程中,在滿足產(chǎn)品工作要求的情況下,應(yīng)盡可能多的采用標(biāo)準(zhǔn)件,提高其互換性要求,以減少產(chǎn)品的設(shè)計(jì)生產(chǎn)成本。
三、 本設(shè)計(jì)(論文或其他)應(yīng)達(dá)到的要求
1、 該部件工作時(shí),能運(yùn)轉(zhuǎn)正常;
2、 熟悉有關(guān)標(biāo)準(zhǔn)、規(guī)格、手冊(cè)和資料的應(yīng)用;
3、 擬定工作機(jī)構(gòu)和傳動(dòng)系統(tǒng)的運(yùn)動(dòng)方案,并進(jìn)行多方案對(duì)
分析;
4、 對(duì)無軸攪拌機(jī)傳動(dòng)系統(tǒng)具有初步分析能力和改進(jìn)設(shè)計(jì)的能 力;
5、 理論聯(lián)系實(shí)際的工作方法和獨(dú)立工作能力深化和提高;
6、設(shè)計(jì)繪制零件工作圖若干;
7、編制設(shè)計(jì)說明書1份。
四、 接受任務(wù)學(xué)生:
機(jī)械97 班 姓名 龍躍
五、 開始及完成日期:
自2012年11月12日至2013年5月25日
六、 設(shè)計(jì)(論文)指導(dǎo)(或顧問):
指導(dǎo)教師 簽名
簽名
簽名
教研室主任
[科學(xué)組組長] 簽名
系主任 簽名
2012年11月12日
I
英文原文:
Designing and Modeling a Torque and Speed Control Transmission (TSCT)
1 Background
The Partnership for a New Generation of Vehicles (PNGV) was formed between the Federal Government, Ford Motor Company, General Motors Corporation, and Chrysler Corporation. The goal of this partnership was to allow the major U.S. automotive manufactures to collaborate with each other and produce high fuel
efficiency, low emissions vehicles for sale to the general public. The performance objective for these manufacturers was to create mid-sized passenger cars capable of attaining an 80 mpg (gasoline) composite fuel economy rating on the Environmental Protection Agency (EPA) city and highway cycles. Hybrid vehicle technology has shown great promise in attaining the goals set forth by the PNGV. Hybrid electric vehicles (HEVs) employ technology that helps bridge the gap between the future hope of an electric vehicle (EV) and today’s current vehicles.
Within the past year hybrid electric vehicles have gained an important place in the vehicle market. American Honda Motor Company, Inc. is currently releasing their first generation HEV, the Insight. The Insight is a compact, two passenger, parallel HEV which achieves more than 65 mpg (composite) on the EPA test cycles: the highest of any production vehicle ever tested. Toyota Motor Corporation has also released a hybrid vehicle for sale to the general public. The Toyota Prius is currently for sale in Japan and will come the United States in the beginning of the year 2000. The Prius is a four passenger combination hybrid employing an a gasoline engine, high power electric motor, and an electromechanical continuously variable transmission (CVT) comprised of a planetary geartrain and a high power alternator/motor. It is through technology incorporated in vehicles such as the Prius that automotive transmission design and operation will make significant new advances.
1.1 Current Automotive Transmission Technologies
With the advent of the automobile also came the creation of the automotive transmission. Early vehicles were simple with manual controls for all functions including the transmission. As advances have been made in vehicles over the past several decades, transmission technology has also advanced. The automatic transmission has nearly replaced the manual transmission in all but economy and performance cars. This trend can be attributed to ease of use, higher power engines becoming available, and congestion in urban areas. Another new transmission technology beginning to see application particularly in foreign markets is the continuously variable transmission that offers continuous operation without shifting between a high and low gear ratio.
These three types of transmissions are all similar in function though their objectives are accomplished in different ways. The capabilities of these transmissions are limited to decoupling the engine speed from the speed of wheels and thereby providing one of several forward or reverse gear ratios. Each transmission is also a single input (engine) and single output (drive device). There are typically no provisions for attaching multiple power sources or for extracting power from more than one point.
The exception to this is heavy-duty transmissions equipped with provisions for a power take off for driving auxiliary mechanical equipment. Single input, single output operation limits drivetrain flexibility for newer systems employing multiple power sources such as those used in the next generation of hybrid vehicles.
1.1.1 Manual Transmission Operation
Manual transmissions are the least complex and oldest design of power transmission available. In simplest form, a manual transmission is a linear combination of a clutch and a directly geared connection. More sophisticated examples rely on this design but add the ability to select other gear ratios to allow different output speeds for the same input speed. Of these types of transmissions, there are two variations: synchronized and unsynchronized. Synchronized manual transmissions are typically used for light duty applications. Coupled to each gear is a synchronizer that allows the operator to disengage the clutch and select whatever gear necessary. The selection of a different gear engages the synchronizer, which then matches engine input speed and transmission output speed before the gears are engaged.
Unsynchronized manual transmissions are more robust by nature. The operator must double-clutch between shifts to match engine and transmission speed manually. However, this allows a transmission of a given size to handle greater load as space previously occupied by the synchronizers can now be dedicated to the use of wider gears. Applications of these types of manual transmissions are for over-the-road trucks and up to larger equipment with total vehicle weights over 100 tons. [1]
1.1.2 Automatic Transmission Operation
Automatic transmissions are a complex assembly of many components that allow for seamless power transmission. Those currently available in production vehicles use torque converters, clutches, and planetary gear sets for the selection of different output ratios. The engine is connected to the torque converter that acts very much like a clutch under some conditions while more like a direct connection in others. The torque converter is a hydraulic coupling that will slip under light load (idle), but engage progressively under higher load. While the torque converter transmits power to the transmission there is a speed reduction across the unit during low speed operation. This reduction is typically between 2.5:1 to 3.5:1. Once higher vehicle speeds are attained, the torque converter input and output may be locked together to achieve a direct drive though the unit. The output of the torque converter is typically connected to a hydraulic pump that provides the necessary pressure to engage different clutches within the transmission and the planetary drive. Different gear ratios are created through the use of two or more planetary gearsets. These gearsets are combined with clutches on different elements. By clutching and declutching different elements, multiple gear ratios are possible.
Basic automatic transmissions are equipped with a single control input that is throttle position. The combination of this with the hydraulic pressure created within the transmission allows for mechanical open loop control of all gear selections. Newer variations of the automatic transmission are equipped with electronic feedback controls.
Shift logic is dependent on many more variables such as engine speed, temperature, current driving trend, throttle position, vehicle accelerations, etc. This allows the transmission controller to monitor vehicle operation and using a rule-based control strategy decide which gear is best suited to the current driving conditions. Newer systems are also integrated with the engine controller such that a vehicle control computer has authority over engine and transmission operation simultaneously. This allows for such features as increasing engine speed during high-speed downshifts to match engine and transmission speed for smoother shifting and retarding fueling and ignition timing during high power upshifts to reduce ‘jerk’. Previously, transmission
control was much simpler because overrunning clutches were employed in higher gears that only allowed for coasting to conserve fuel. [1]
1.1.3 Continuously Variable Transmission Operation
Continuously variable transmissions are one of the emerging transmission technologies of the last twenty years. This type of transmission allows power transmission over a given range of operation with infinitely variable gear ratios between a high and low extreme. These transmissions are constructed using two variable diameter pulleys with a belt connecting the two. As one pulley increases in size, the other decreases. This is accomplished by locating on one shaft a stationary sheave and a movable sheave. For automotive applications, a hydraulic actuator controls movement of the sheave. However, centrifugal systems along with high power electronic solenoids may be used. A second shaft in the CVT contains the other stationary sheave and movable sheave also controlled hydraulically. A flexible metal belt is fitted around these two pulleys and the movable sheaves are located on opposite sides of the belt.
There are two variations of this type of transmission: push belt and pull belt. Pull belt CVTs were the first type to be manufactured due to simplicity. A clutch is attached between the first pulley and the engine while the output of the second pulley was connected to a differential and thus the wheels. A hydraulic pump is used to control the diameter of the two different pulleys. As power is applied the first pulley creates a torque that is transmitted through the belt (under tension) to the second pulley. Control of the transmission ratio is usually a direct relationship dependent upon throttle position.
Push belt CVTs, similar in design to the Van Doorne, are much the same as pull belt CVTs, except that power is transmitted through the belt while under compression. This provides a higher overall efficiency due to the belt being pushed out of the second pulley and lowering frictional losses. Current work with these transmissions is being focused on creating larger units capable of handling more torque. Efficiency of the CVT is directly related to how much tension is in the belt between the two pulleys. CVT torque handling capacity increases as tension in the belt increases. However, this increased tension lowers power transmission efficiency. The belt must slide across the faces of each pulley as it enters and exits upon each half rotation. This sliding of the belt creates frictional losses within the system. In addition, there may be significant parasitic losses associated with raising the hydraulic pressure required to move or maintain the position of the sheaves in each pulley. [2]
1.1.4 Automatically Shifted Manual Transmission Operation
Automatically shifted manual transmissions are a fairly recent innovation. The benefit of the manual transmission is that (due to the direct mechanical connection through fixed gears) efficiency is very high. The drawback is that there must be some interaction with the user in the selection and changing of gears. Automatically shifted manuals were created to address this issue. These types of transmissions are traditionally synchronized manual transmissions with the addition of automation of the gear selection and control of the clutch. A logic controller is also employed to decide when and how to shift. Automatic shifting is usually accomplished through the use of electro-hydraulics. A high-pressure electric pump supplies pressure to hydraulic solenoids that are used to shift the transmission. A hydraulic ram is also used to engage and disengage the clutch. Current versions of these transmissions also employ unsynchronized gears. This allows for overall smaller packaging to accomplish the same task. Input speed of the engine is monitored along with layshaft speed. When a gear change is initiated, the controller opens the clutch, shifts to the desired gear while matching engine and lay shaft speed, and then closes the clutch again. This shifting operation can all be achieved in less than one third of a second. Automatically shifted manual transmissions shift gears faster than humanly possible. [3]
1.1.5 Manually Shifted Automatic Transmission Operation
Manually shifted automatic transmissions are a variation on control of the transmission. The user is allowed to select either automatic or manual shifting modes. During automatic mode, the transmission functions identically to an automatic transmission. While in manual shift mode however, the transmission controller allows the user full authority over gear changes as long as the gear change will not overspeed the engine. This mode of operation traditionally offers the user tighter, more positive shift feel. The only requirement of an automatic transmission for manual shifting is that shifts must be accomplished rapidly enough to allow the user a feeling of fluidity. The act of shifting must provide the immediate desired response. [3]
1.1.6 Planetary Gear Drive Transmission Operation
Planetary gear sets are unique in that the combination of gears creates a two
degree-of-freedom system. The gear sets are comprised of a ring gear, a sun gear in the center, and planetary gears that contact both the ring and the sun gears. Motion of the planetary gears is controlled by the carrier on which each of the planetary gears rotate.
The carrier maintains the position of the planets in relation to each other but allows rotation of all planets freely. Inputs (or outputs) to the gear train are the ring gear, sun gear, and planetary carrier. By prescribing the motion of any two of these parameters, the third is fixed in relation to the other two. By employing one planetary geartrain, a fixed ratio between input and output is created. Increasing or decreasing the number of teeth on the sun and ring gears can change this ratio. This in turn changes the number of teeth on the planetary gears, which has no other effect as these gears act as idlers.
When combining more than one planetary gear train at one time, braking or allowing the movement of different elements can create a wide range of effective operation in terms of relative speeds, torque transfer, and direction of rotation. This is the type of system that is used in automatic transmissions described above. These systems are also employed in large stationary power transmission applications. [1]
1.2 Current Hybrid Electric Vehicle Transmission Design
Hybrid vehicles are vehicles that utilize more than one power source. Current propulsion technologies being favored are compression ignition (CI) engines, spark ignition(SI) engines, hydrogen-fueled engines, fuel cells, gas turbines, and high power electric drives. Energy storage devices include batteries, ultra-capacitors, and flywheels.
Hybrid powertrains can be any combinations of these technologies. The aim of these vehicles is to use cutting edge technology combined with current mass-produced components to achieve much higher fuel economy combined with lower emissions without raising consumer costs appreciably. These vehicles are targeted to bridge the gap between current technology and the future hope of a Zero Emission Vehicle (ZEV), presumably a hydrogen-fueled fuel cell vehicle. The operation of these systems must also be transparent to the user to enhance consumer acceptability and the vehicle must still maintain all required safety features with comparable dynamic performance all at an acceptable cost.
By combining multiple power sources, overall vehicle efficiency can be improved by the ability to choose the most efficient power source during the given operating conditions. This is key in improving vehicle efficiency because current battery technology dictates that nearly all total energy used by the vehicle across a reasonable range of driving comes from the on-board fuel. Highly adaptive control strategies that may be employed in the next generation of HEVs may monitor vehicle speed, desired torque, energy available, and recent operating history to choose which mode of operation is most beneficial. These advanced control schemes will maximize the usage of the fuel energy available by choosing the most efficient means of power delivery at any instant. The reduced usage of energy for a given amount of work may also result in lower exhaust emissions due to a reduction in fuel energy used.
1.2.1 The Advantages and Disadvantages of Series Hybrid Vehicles
Series hybrid vehicles typically have an internal combustion engine (ICE) that is
coupled directly to an electric alternator. The vehicle final drive is supplied entirely by an electric traction motor that is supplied energy by the battery pack or combination of engine and alternator. The benefit of this type of operation is the engine speed and torque are decoupled from the instantaneous vehicle load and the engine needs only to run when battery state of charge (SoC) has dropped below some lower level. This allows engine operation to be optimized for both fueling and ignition timing in the case of a spark ignited engine, or fueling and injection timing for a compression ignition engine. The engine is also operated in the most efficient speed and torque without encountering transient operation regardless of load. The result is excellent fuel economy and low emissions. Series HEV operation is exceptionally well suited to highly transient vehicle operation which is prevalent in highly urban areas and city driving. The disadvantage to series hybrid operation is the efficiency losses associated with converting mechanical to electrical and then electrical to mechanical energy. Further losses in system efficiency are realized when the energy is stored in the battery pack for later use. Only a fraction of the energy put into the batteries can be returned due to the internal resistance of the batteries. The mechanical energy of the engine is directly converted to electricity by an alternator that has losses both in internal resistance and eddy currents present. Further losses are incurred when this electrical energy is converted back to mechanical energy by the traction motor and controller. Dynamic performance is also limited, as the engine cannot supplement the traction motor in powering the vehicle.
1.2.2 The Advantages and Disadvantages of Parallel Hybrid Vehicles
Parallel systems also employ two power sources, typically an engine and a traction motor with both directly coupled to the wheels typically through a multi-speed transmission. This requires that the engine see substantial transient operation. However, the motor can act as a load-leveling device allowing the engine to operate in a more efficient operating region. When the vehicle is operating in a low load state the engine can be decoupled from the drivetrain and shut off, or the motor can be used to charge while driving creating a greater power demand for the engine and storing energy in the battery pack. The disadvantage of parallel hybrids is that direct connection of the engine to the wheels requires transient engine operation. This operation lowers fuel economy and increases exhaust emissions especially when employing SI engines. Ignition timing and fueling cannot be optimized for a single region of operation either. However, dynamic performance of parallel hybrids is much better than that of series hybrids using the same components. Much more power is available as both the engine and motor can provide power to the wheels simultaneously. These characteristics lend parallel HEVs to excel in higher load, less transient situations and when using high efficiency engines such as CI engines.
1.2.3 The Advantages and Disadvantages of Combination Hybrid Vehicles
The third variation of hybrid vehicle drivetrains is the combination, which is a system that can function both as a series and parallel hybrid. Complex combinations of engines, alternators, and motors can accomplish this with geared connections and multiple clutches. By clutching and declutching different elements, a combination can be designed to function as a series hybrid under low speed transient conditions and then as a parallel hybrid under higher speed and load. This allows for increased efficiency as each mode of operation is employed under the ideal operating conditions. Drawbacks to these systems are increased mechanical and drivetrain control complexity along with higher weight associated with more components. Controlling these types of systems is much more