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畢業(yè)設計(論文)任務書
學生姓名
指導教師姓名
題目名稱
比亞迪F3R手動變速器設計
一、設計(論文)目的、意義
比亞迪轎車在我國國產車當中比較普及,變速器的功用是在不同的使用條件下, 改變發(fā)動機傳到驅動輪上的轉矩和轉速, 使汽車得到不同的牽引力和速度, 同時使發(fā)動機在最有利的工況范圍內工作。通過對變速器的設計,使其變速器性能更好,同時使學生全面復習過去所學知識,因此具有一定的實際意義。
二、設計(論文)內容、技術要求(研究方法)
(一)設計內容
利用比亞迪F3R相關發(fā)動機參數(shù),完成變速器結構布置和設計。設計的主要內容包括:選擇發(fā)動機參數(shù),確定變速器結構類型,對變速器中的各級齒輪和軸等零部件進行設計,并對主要零部件進行校核。
(二)研究方法
1、 查閱相關資料,對比各種變速器優(yōu)缺點,初步確定設計方案。
2、 參照比亞迪F3R實車,為最終設計方案提供依據(jù)。
3、 利用Autocad畫出裝配圖及零件圖。
三、設計(論文)完成后應提交的成果
(一)計算說明部分
完成設計說明書1.5萬字。包括變速器各級齒輪和軸等零部件設計及強度校和。
(二)圖紙部分
變速器裝配圖零件圖若干張,共計折合3張A0圖紙。
四、設計(論文)進度安排
(1)調研、查閱相關資料、完成開題報告 第1~2周(3月3日~3月16日) (2)確定總體方案 第3~4周(3月17日~3月30日) (3)對變速器結構進行設計第5~6周(3月31日~4月13日) (4)對變速器尺寸進行設計7~8周(4月14日~4月27日)
(5)畫變速器的零件圖第第8~9周(4月21日~5月4日) (5)畫變速器的裝配圖第9~10周(4月28日~ 5月11日)
(6)完成設計說明書第11~13周(5月12日~6月2日) (7)設計審核、修改 第14~16周(6月3日~6月23日) (8)畢業(yè)設計答辯準備及答辯 第17周(6月24日~7月1日)
五、主要參考資料
[1] 余志生. 汽車理論[M],機械工業(yè)出版社,1987
[2]工程中的有限元方法(第3版).機械工業(yè)出版社,2004
[3] 吳鎮(zhèn)著.理論力學.上海:上海交通大學出版社,1997
[4]孫桓主編.機械設計.機械工業(yè)出版社出版
[5] 蔣崇賢,何明輝《專用汽車設計》 武漢工業(yè)大學出版社
[6]陳家瑞主編.汽車構造.人民交通出版社出版
[7] 黃天澤,黃金陵.汽車車身結構與設計.機械工業(yè)出版社,2000
[8]呂慧瑛.機械設計基礎.北京:清華大學出版社,2002
[9]相關期刊,網絡
六、備注
指導教師簽字:
年 月 日
教研室主任簽字:
年 月 日
畢業(yè)設計開題報告
設 計 題 目: 比亞迪F3R手動變速器設計
院 系 名 稱: 汽車與交通工程學院
專 業(yè) 班 級:
學 生 姓 名:
導 師 姓 名:
開 題 時 間:
指導委員會審查意見:
簽字: 年 月 日
目錄
一課題研究現(xiàn)狀,選題目的、依據(jù)和意義 3
1.課題研究現(xiàn)狀 3
2.選題的目的依據(jù)和意義 5
二、設計(論文)的基本內容,擬決的主要問題 5
1.設計的基本內容 5
2.擬解決的主要問題 5
三、技術路線(研究方法) 6
四、進度安排 6
五、參考文獻 7
六、備注 7
七、指導教師意見 7
SY-025-BY-3
畢業(yè)設計(論文)開題報告
學生姓名
趙磊
系部
汽車與交通工程學院
專業(yè)、班級
車輛工程BW07-8
指導教師姓名
趙國遷
職稱
高級實驗師
從事
專業(yè)
汽車運用
是否外聘
□是否
題目名稱
比亞迪F3R手動變速器設計
一課題研究現(xiàn)狀,選題目的、依據(jù)和意義
1.課題研究現(xiàn)狀
21世紀,汽車工業(yè)成為各國經濟發(fā)展的支柱產業(yè)之一,汽車企業(yè)對各系統(tǒng)部件的設計需求旺盛。其實,汽車與人一樣,也是有著整套健康系統(tǒng)的有機結合體。發(fā)動機是心臟,車輪、底盤與懸掛是軀干與四肢,然而連接它們的,是類似于人體經脈的變速器系統(tǒng)。如果汽車喪失了變速器這個中心環(huán)節(jié),心臟、四肢與軀干再好,汽車只能如同植物人般成為廢鐵一堆!可以說,變速器是伴隨著汽車工業(yè)出現(xiàn)的必然產物,是汽車上的必需品。在完成了最基本的傳動功能之外,我們對變速器的要求也是越來越高,這是變速箱演變過程的首要催產素[1]。由此可見,對汽車的變速器進行研究具有十分重要的意義。
由于汽油機的轉速較高,而產生的扭矩又較小,因此需要一種降速增扭的機構——變速器,以保證汽車在各種道路條件下均能正常地行駛。1894年,一個法國工程師給一輛汽車裝上世界上第一個變速器至今,汽車變速器已經經過了一百多年的發(fā)展。變速器為汽車重要的組成部分,是承擔放大發(fā)動機扭矩,配合引擎功扭特性,實現(xiàn)理想動力傳遞,從而適應各種路況實現(xiàn)汽車行駛的主要裝置。發(fā)動機是汽車的心臟,發(fā)動機產生的動力必須經過傳動系統(tǒng)才能驅動車輪轉動[2]。
變速器是傳動系統(tǒng)的心臟。由于發(fā)動機的轉速和轉矩的變化范圍小,而汽車行駛速度的變化范圍廣,所以一開始傳動系統(tǒng)就設置了變速器。變速器的作用:①改變汽車的傳動比,擴大驅動車輪轉矩和轉速的范圍,使車輛適應各種變化的行駛工況,同時使發(fā)動機在理想的工況下工作;②在發(fā)動機轉矩方向不變的前提下,實現(xiàn)汽車的倒退行駛;③實現(xiàn)空擋,中斷發(fā)動機傳遞給車輪的動力,使發(fā)動機能夠起動、怠速。100多年中,變速器經歷了用變速桿改變鏈條的傳動比一手動變速器一有級自動變速器一無級自動變速器的發(fā)展歷程[3]。
早期的汽車傳動系統(tǒng),從發(fā)動機到車輪之間的動力形式很簡單。發(fā)動機驅動一組錐齒減速齒再傳動到一根軸和皮帶輪。皮帶輪和驅動橋上的內齒輪嚙合,使汽車行駛,大齒輪用來加速,能使汽車達到32 km/h的速度。如果遇到上坡,而爬坡能力不夠時,駕駛員就停下車子,把小鏈輪嚙合后進行驅動.。
(1)變速器類型及特點
現(xiàn)在市場上的變速器細分為5類手動變速器(MT),手動自動一體變速器(AMT),無級變速器(CVT)、雙離合器變速器(DCT)和自動變速器(AT),各自都有不同的優(yōu)勢。按變速器功能可分為兩類:手動變速器和自動變速器。手動變速器即MT,自動變速器包括傳統(tǒng)AT、AMT、CVT及DCT。如果按變速結構可分為三類:圓柱齒輪、行星齒輪及錐盤。圓柱齒輪類包括MT、AMT、DCT;行星齒輪類包括傳統(tǒng)AT及使用了多片濕式離合器替代液力變矩器的AT。錐盤類包括金屬鋼帶CVT及半環(huán)面錐輪無級變速器等??刂萍夹g和電子信息技術的高速發(fā)展,使得自動變速器得到快速發(fā)展,手動變速器向自動變速器發(fā)展的趨勢越發(fā)明顯。新技術的發(fā)展一方面仍在不斷改善現(xiàn)有變速器的性能。我所要設計的是手動變速器也就是MT。MT的優(yōu)勢是傳動效率高及成本低,但換檔復雜。AMT傳動效率也高。且具備自動換檔功能,但換檔沖擊性有待解決[4]
MT主要工作原理是通過變速操縱桿撥動不同齒輪組問的嚙合套從而組成不同的檔位,因為每檔齒輪組的齒數(shù)是固定的,所以各檔的變速比是一定的,屬于有級變速器。在低速時,讓傳動比大的齒輪副工作;而在高速時,讓傳動比小的齒輪副工作?!皟奢S一中間軸”,它們構成了變速器的主體,還有一根倒擋惰輪軸常見的手動變速器由鑄鐵或鋁制變速器殼體、軸、軸承、齒輪、同步器和換擋機構組成MT變速器應用的歷史時間最長,其產品技術發(fā)展十分有限,憑借與其它形式變速器相比的成本優(yōu)勢及較高的傳動效率,仍然占據(jù)乘用車變速器市場上相當?shù)氖袌龇蓊~[5]。
(2)國外手動變速器研究現(xiàn)狀
國外在手動變速器的研究上開始趨于自動變速器,這是為了節(jié)省燃油以及緩解駕駛者在頻繁換擋中產生的疲勞感等一系列缺點。據(jù)預測,2013年歐洲變速器市場上,配備手動變速器的汽車將占52%,配備自動手動變速器的將占10%,配備無極變速器的將占2%,配備雙離合器變速器的將占16%,配備自動變速器的將占20%。,可見手動變速器依然占據(jù)著半壁江山,這證實了手動變速器在消費者心中的分量。國外專家指出,新變速器產品還在不斷研發(fā)的過程中,因此,今后汽車市場的變速器情況可能還會出現(xiàn)一些變化。 目前許多變速器生產企業(yè)正在研發(fā)一些燃油經濟性更好、換擋性能更高的變速器,以滿足市場上的多層次需求。例如,某公司正在研制一種傳動效率可達92%、換擋性能更好的變速器。
(3)國內手動變速器研究現(xiàn)狀及發(fā)展
改革開放30年來,我國汽車變速器行業(yè)隨著整車行業(yè)的快速發(fā)展而不斷發(fā)展壯大,形成了一批頗具規(guī)模的變速器企業(yè)。大多數(shù)本土變速器企業(yè)在引進消化吸收國外先進技術方面取得了突出成績,并不斷堅持自主創(chuàng)新,在手動變速器領域,,尤其是在重型車用和微型車用手動變速器上,涌現(xiàn)了大量自主創(chuàng)新的產品。另外,一些跨國公司獨資或合資的變速器企業(yè)開始陸續(xù)在中國設廠,為滿足持續(xù)高速增長的中國汽車市場需求作出了非常大的貢獻。
隨著中共十七屆五中全會召開,中國政府起草并通過了國家“十二五”規(guī)劃,規(guī)劃中明確提出,中國迫切需要完成從汽車大國到汽車強國的轉變。
中國要成為汽車強國,首先要克服自主技術這塊短板。而汽車的核心部分——動力總成,仍是國內一直沒有完全掌握的關鍵汽車零部件技術之一。
目前,在中國乘用車手動變速器市場,國產品牌已占主導地位,隨著中國乘用車市場的快速發(fā)展,對變速器的要求無論從數(shù)量上還是從技術水平上均不斷提高,但技術落后嚴重阻礙著國產品牌變速器企業(yè)的發(fā)展。雖然現(xiàn)在越來越多的人在買車的時候選擇了自動變速器,但是在中國,手動變速器仍然是車用變速器的主流。具體有兩個原因:首先,目前國內企業(yè)已經基本掌握對手動變速器的開發(fā),所以在一定程度上加大了手動變速器的價格優(yōu)勢;另外,絕大多數(shù)中國駕駛者在學車時就用的是手動車,他們更加享受手動車帶來的駕駛樂趣
2006年中國手動檔乘用車共銷售354.54萬輛,較2005年增長20.54%。2007年1~9月份,手動檔乘用車共銷售308.65萬輛,同比增長21.70%。在中國乘用車用手動變速器市場中,國產品牌占主導地位,進口量很小,因而隨著手動檔乘用車銷量的快速增長,手動變速器市場也將不斷擴大[6]。
2.選題的目的依據(jù)和意義
比亞迪股份有限公司由王傳福創(chuàng)立于1995年,2002年7月31日在香港主板發(fā)行上市,是一家擁有IT和汽車兩大產業(yè)群的高新技術民營企業(yè)。2003年,比亞迪收購西安秦川汽車有限責任公司(現(xiàn)“比亞迪汽車有限公司”),正式進入汽車制造與銷售領域,開始民族自主品牌汽車的發(fā)展征程。發(fā)展至今,在整車制造、模具研發(fā)、車型開發(fā)等方面都達到了國際領先水平,產業(yè)格局日漸完善并已迅速成長為中國最具創(chuàng)新的新銳品牌。汽車產品包括各種高、中、低端系列燃油轎車,以及汽車模具、汽車零部件、雙模電動汽車、純電動汽車等。代表車型包括F0、F3、F3-R兩廂、F6、S8硬頂敞篷跑車、F3DM雙模電動汽車、S6(SUV)、M6(MPV)等。應用在比亞迪F3R車型上的手動變速器技術比較落后,但是手動變速器在變速器市場一直占據(jù)重要份額,在中國,更是贏得了大多數(shù)消費者的偏愛。無論是燃油經濟型上的優(yōu)勢,實施上的低成本,還是駕駛者的操縱感,都使得手動變速器成為OEM在設計某款汽車時的重要考慮。然而手動變速器也有其自身的缺點,由于手動變速器在穩(wěn)定性、燃油經濟性和舒適性上存在著一定的不足,而且在當今的大城市中,堵車”現(xiàn)象愈演愈烈,駕駛員需頻繁地踩離合器換檔,體力消耗大,發(fā)動機很難工作在最佳的狀態(tài),動力性沒有完全發(fā)揮,經濟性差,排氣中有害物質含量高,污染嚴重,所以鑒于以上缺點必須設計出一款克服這些缺點并應用到比亞迪F3R轎車上的手動變速器使得手動變速器的路能夠走的更遠。
二、設計(論文)的基本內容,擬決的主要問題
1.設計的基本內容
(1)研究國內外汽車變速器研究現(xiàn)狀及發(fā)展歷史,理解本課題研究的意義
(2)分析各種汽車變速器的基本原理和優(yōu)缺點
(3)利用比亞迪F3R相關發(fā)動機參數(shù),完成變速器結構布置和設計。
(4)選擇發(fā)動機參數(shù),確定變速器結構類型,對變速器中的各級齒輪和軸等零部件進行設計,并對主要零部件進行校核。
2.擬解決的主要問題
(1)通過文獻資料,熟悉汽車變速器設計和CAD的相關知識,掌握汽車變速器設計計算方法。
(2)調研,掌握汽車變速器設計過程。
(3)鞏固以往所學的理論知識,熟悉變速器結構,掌握變速器的設計方法和CAD軟件在變速器設計中的應用步驟,提高動手能力為以后打下良好基礎
(4)確定汽車變速器設計的各項參數(shù),計算確定主要零件的參數(shù)和尺寸,完成CAD圖紙
三、技術路線(研究方法)
完成畢業(yè)設計和設計說明書
調查研究
變速器結構分析與類型選擇
變速器設計計算
齒輪大小與齒數(shù)計算
軸參數(shù)計算
變速器主要參數(shù)校核
利用AUTOCAD進行繪圖
四、進度安排
(1)調研、查閱相關資料、完成開題報告 第1~2周(3月3日~3月16日) (2)確定總體方案 第3~4周(3月17日~3月30日) (3)對變速器結構進行設計第5~6周(3月31日~4月13日) (4)對變速器尺寸進行設計7~8周(4月14日~4月27日)
(5)畫變速器的零件圖第第8~9周(4月21日~5月4日) (5)畫變速器的裝配圖第9~10周(4月28日~ 5月11日)
(6)完成設計說明書第11~13周(5月12日~6月2日) (7)設計審核、修改 第14~16周(6月3日~6月23日) (8)畢業(yè)設計答辯準備及答辯 第17周(6月24日~7月1日)
五、參考文獻
[1] 向立明 汽車變速器的發(fā)展歷史及未來趨勢 石家莊 2007,1
[2]工程中的有限元方法(第3版).機械工業(yè)出版社,2004
[3] 鄭勁,張子成 中國汽車變速器市場高速發(fā)展.中機系(北京)信息技術研究院 2008,12
[4]孫桓主編.機械設計.機械工業(yè)出版社出版
[5] 余志生. 汽車理論[M],機械工業(yè)出版社,1987
[6] 余志生.汽車理論[M].第3 版.北京:機械工業(yè)出版社,2000.
[7] 理論力學.上海:上海交通大學出版社,1997
[8] 濮良貴,紀名剛.機械設計(第七版)北京:高等教育出版社,1990.
[9] 孫桓,陳作模.機械原理(第六版) 北京:高等教育出版社,2000
[10] 肖生發(fā),趙樹朋.汽車構造 北京:中國林業(yè)出版社,2006
[11] 劉惟信.汽車變速器設計 北京:清華大學出版社,2001
[12] 浙江省交通學校 編.汽車構造圖冊(底盤) 北京:人民交通出版社,1991
[13] 關文達.汽車變速器設計(第二版) 北京:機械工業(yè)出版社,2006
[14] 郝京順汽車變速器的發(fā)展 2005(04)
[15] 胡朝峰.過學迅.汪斌汽車變速器技術的發(fā)展與展望]-汽車研究與開發(fā) 2005(05)
[16]汽車變速器傳動系統(tǒng)綜合分析 -制造技術與機床2007(9) 期刊論文
[17]王榮霞 Masta軟件在汽車變速器設計中的應用 2008會議論文
[18]期刊論文徐梟.周榮.XU Xiao.ZHOU Rong 輕型汽車變速器市場分析與預測 -汽車工程師2009(6)
[19]會議論文肖婷玲.鐘福東O形圈在汽車變速器中的質量整改實例 2008
[20]Shichi Sano,Yoshimi furukawa,etc.Four Wheel Steering System with RearWheel Steer Angle:SAE Technical Paper Series,1986,5
[21]A.Higuchi,Y. Saitoh. Optimal Control of Four Wheel Steering Vehicle:Vehicle System Dynamic,1993,2
六、備注
七、指導教師意見
簽字: 年 月 日
8
畢業(yè)設計(論文)成績評定表
學生姓名
性別
男
院系
汽車與交通工程學院
專業(yè)
車輛工程
班級
設計(論文)題目
比亞迪F3R手動變速器設計
平時成績評分(開題、中檢、出勤)
指導教師姓名
職稱
指導教師
評分(X)
評閱教師姓名
職稱
評閱教師
評分(Y)
答辯組組長
職稱
答辯組
評分(Z)
畢業(yè)設計(論文)成績
百分制
五級分制
答辯委員會評語:
答辯委員會主任簽字(蓋章): 院系公章: 年 月 日
注:1、平時成績(開題、中檢、出勤)評分按十分制填寫,指導教師、評閱教師、答辯組評分按百分制填寫,畢業(yè)設計(論文)成績百分制=W+0.2X+0.2Y+0.5Z
2、評語中應當包括學生畢業(yè)設計(論文)選題質量、能力水平、設計(論文)水平、設計(論文)撰寫質量、學生在畢業(yè)設計(論文)實施或寫作過程中的學習態(tài)度及學生答辯情況等內容的評價。
畢業(yè)設計指導教師評分表
學生姓名
院系
汽車與交通工程學院
專業(yè)、班級
指導教師姓名
職稱
高級實驗師
從事
專業(yè)
汽車運用
是否外聘
□是否
題目名稱
比亞迪F3R手動變速器設計
序號
評 價 項 目
滿分
得分
1
選題與專業(yè)培養(yǎng)目標的符合程度,綜合訓練情況;題目難易度
10
2
題目工作量;題目與工程實踐、社會實際、科研與實驗室建設等的結合程度
10
3
綜合運用知識能力(設計涉及學科范圍,內容深廣度及問題難易度);應用文獻資料能力
15
4
設計(實驗)能力;計算能力(數(shù)據(jù)運算與處理能力);外文應用能力
20
5
計算機應用能力;對實驗結果的分析能力(或綜合分析能力、技術經濟分析能力)
10
6
插圖(圖紙)質量;設計說明書撰寫水平;設計的實用性與科學性;創(chuàng)新性
20
7
設計規(guī)范化程度(設計欄目齊全合理、SI制的使用等)
5
8
科學素養(yǎng)、學習態(tài)度、紀律表現(xiàn);畢業(yè)論文進度
10
得 分
X=
評 語:(參照上述評價項目給出評語,注意反映該論文的特點)
工作態(tài)度: 好□ 較好□ 一般□ 較差□ 很差□
研究能力或設計能力:強□ 較強□ 一般□ 較弱□ 很弱□
工作量: 大□ 較大□ 適中□ 較少□ 很少□
說明書規(guī)范性: 好□ 較好□ 一般□ 較差□ 很差□
圖紙規(guī)范性: 好□ 較好□ 一般□ 較差□ 很差□
成果質量(設計方案、設計方法、正確性)
好□ 較好□ 一般□ 較差□ 很差□
其他:
指導教師簽字: 年 月 日
優(yōu)秀畢業(yè)設計(論文)推薦表
題 目
比亞迪F3R手動變速器設計
類別
畢業(yè)設計
學生姓名
院(系)、專業(yè)、班級
指導教師
職 稱
高級實驗師
設計成果明細:
答辯委員會評語:
答辯委員會主任簽字(蓋章): 院、系公章: 年 月 日
備 注:
注:“類別”欄填寫畢業(yè)論文、畢業(yè)設計、其它
摘 要 本文設計研究了三軸式五擋手動變速器 首先 對于變速器的工作原理做了闡述 從傳動機構到倒檔布置方案都一一做了詳細的說明 完成了換擋機構形式和軸承的選 擇等 特別值得一提的是在倒檔的選擇和布置上 因為變速箱在低檔工作時作用有較 大的力 所以一般變速箱的低檔都布置靠近軸的后支承處 緊接著對變速器的各擋齒輪和軸做了詳細的設計計算 包括了檔數(shù) 傳動比 中 心距以及各檔齒輪的齒數(shù) 并且進行了強度校核 緊接著對一些標準件進行了選型 其中包括同步器 操縱機構 固定件以及密封件等等 最后進行的是齒輪 軸以及軸承的校核 其中齒輪校核包括彎曲強度和接觸應力 軸校核包括強度和剛度的計算 軸承校核的則是其壽命計算 并講 述 了 變 速 器 中 各 部 件 材 料 的 選 擇 關鍵字 變速器 設計 齒輪 軸 校核 I ABSTRACT This design of a three axis five speed manual transmission First the working principle of transmission are described in detail from the transmission to reverse layout programs are all doing a detailed description complete the form and bearing of shift the choice of institutions and so on is particularly worth mentioning is the reverse of the on the selection and arrangement Because the role of transmission in low grade work a greater force it is generally low grade gearbox are arranged near the support at the rear axle Then each block of the transmission gears and shafts made a detailed design calculations including the gears transmission ratio center distance and the number of teeth of the gear profile and strength check carried out followed by a number of standard parts were selected type including synchronization control mechanism fixed fittings and seals and so on Finally the gear shaft and bearing checking checking gear which includes bending strength and contact stress axial strength and rigidity checking including the calculation of the bearing checking is its life span and about each transmission component materials of choice Keywords Transmission Design Gear Axis Checking 0 目 錄 摘 要 I ABSTRACT II 第 1 章 緒 論 1 1 1 選題的背景 1 1 2 設計目的及意義 2 1 3 國內外研究現(xiàn)狀 2 1 3 1 國內研究現(xiàn)狀 2 1 3 2 國外研究現(xiàn)狀 3 1 4 設計主要內容 3 第 2 章 變速器總體方案設計 5 2 1 設計初始數(shù)據(jù) 5 2 2 變速器設計應滿足的基本要求 5 2 3 傳動機構布置方案分析 6 2 3 1 兩軸式變速器和中間軸式變速器的特點分析 6 2 3 2 倒擋布置方案 6 2 3 3 其他問題 7 2 4 各檔齒輪位置安排 7 2 5 變速器齒輪形式與自動脫檔分析 8 2 5 1 齒輪形式 8 2 5 2 變速器自動脫檔分析 9 2 6 換擋機構形式 9 2 7 本章小結 10 第 3 章 變速器主要參數(shù)設計 12 3 1 擋數(shù)的選擇和確定 12 3 2 各檔傳動比的確定 12 1 3 2 1 主減速器傳動比 12 3 2 2 最低檔傳動比計算 13 3 2 3 各檔傳動比 14 3 2 4 初選中心距 14 3 2 5 變速器的外形尺寸 15 3 3 齒輪參數(shù)計算 15 3 3 1 模數(shù)的選取 15 3 3 2 齒形 壓力角及螺旋角的確定 15 3 4 各擋齒輪齒數(shù)的分配 17 3 4 1 確定一擋齒輪的齒數(shù) 17 3 4 2 對中心距進行修正 18 3 4 3 確定常嚙合傳動齒輪副齒數(shù)及變位系數(shù) 18 3 4 4 確定其他各擋的齒數(shù)及變位系數(shù) 18 3 4 5 確定倒擋齒輪齒數(shù)及變位系數(shù) 20 3 5 本章小結 21 第 4 章 變速器的校核 22 4 1 齒輪的損壞形式 22 4 2 齒輪強度計算 22 4 2 1 輪齒的彎曲應力 23 4 2 2 輪齒的接觸應力 24 4 2 3 各檔齒輪的強度校核 25 4 3 軸的結構尺寸設計 32 4 4 軸的強度驗算 33 4 4 1 軸的剛度的計算 33 4 4 2 軸的強度的計算 37 4 5 軸承壽命計算 40 4 6 本章小結 43 第 5 章 同步器的選擇 44 5 1 鎖銷式同步器 44 5 2 鎖環(huán)式同步器 45 5 3 本章小結 46 2 第 6 章 變速器操縱機構的選擇 47 6 1 直接操縱手動換擋變速器 47 6 1 1 變速操縱桿的布置 47 6 1 2 換檔鎖裝置 47 6 2 本章小結 49 結 論 50 參考文獻 51 致 謝 52 附 錄 53 1 附 錄 AUTOMATIC TRANSMISSION The modern automatic transmission is by far the most complicated mechanical component in today s automobile It is a type of transmission that sifts itself A fluid coupling or torque converter is used instead of a manually operated clutch to connect the transmission to the engine There are two basic types of automatic transmission based on whether the vehicle is rear wheel drive or front wheel drive On a rear wheel drive car the transmission is usually mounted to the back of the engine and is located under the hump in the center of the floorboard alongside the gas pedal position A drive shaft connects the transmission to the final drive which is located in the rear axle and is used to send power to the rear wheels Power flow on this system is simple and straight forward going from the engine through the torque converter then trough the transmission and drive shaft until it reaches the final drive where it is split and sent to the two rear transmission On a front wheel drive car the transmission is usually combined with the final drive to form what is called a transaxle The engine on a front wheel drive car is usually mounted sideways in the car with the transaxle tucked under it on the side of the engine facing the rear of the car Front axles are connected directly to the transaxle and provide power to front wheels In this example power floes from the engine through the torque converter to a larger chain that sends the power through a 180 degree turn to the transmission that is along side the engine From there the power is routed through the transmission to the final drive where it is split and sent to the two front wheels through the drive axles There are a number of other arrangements including front drive vehicles where the engine is mounted front to back instead of sideways and there are other systems that drive all four wheels but the two systems described here are by far the most popular A much less popular rear and is connected by a drive shaft to the torque converter which is still mounted on the engine This system is found on the new Corvette and is used in order to balance the weight evenly between the front and rear wheels for improved performance and handling 2 Another rear drive system mounts everything the engine transmission and final drive in the rear This rear engine arrangement is popular on the Porsche The modern automatic transmission consists of many components and systems that designed to work together in a symphony of planetary gear sets the hydraulic system seals and gaskets the torque converter the governor and the modulator or throttle cable and computer controls that has evolved over the years into what many mechanical inclined individuals consider to be an art from Here try to used simple generic explanation where possible to describe these systems 1 Planetary gear sets Automatic transmission contain many gears in various combinations In a manual transmission gears slide along shafts as you move the shift lever from one position to another engaging various sizes gears as required in order to provide the correct gear ratio In an automatic transmission how ever the gears are never physically moved and are always engaged to the same gears This is accomplished through the use of planetary gear sets The basic planetary gear set consists of a sun gear a ring and two or more planet gears all remaining in constant mesh The planet gears are connected to each other through a common carrier which allows the gears to spin on shafts called pinions which are attached to the carrier One example of a way that this system can be used is by connecting the ring gear to the input shaft coming from the engine connecting the planet carrier to the output shaft and locking the sun gear so that it can t move In this scenario when we turn the ring gear the planets will walk along the sun gear which is held stationary causing the planet carrier to turn the output shaft in the same direction as the input shaft but at a slower speed causing gear reduction similar to a car in first gear If we unlock the sun gear and lock any two elements together this will cause all three elements to turn at the same speed so that to output shaft will turn at the same rate of speed as the input shaft This is like a car that is third or high gear Another way we can use a planetary gear set is by locking the planet carrier from moving then applying power to the ring gear which will cause the sun gear to turn in opposite direction giving us reverse gear The illustration in Figure shows how the simple system described above would 3 look in an actual transmission The input shaft is connected to the ring gear the output shaft is connected to the planet carrier which is also connected to a Multi disk clutch pack The sun gear is connected to drum which is also connected to the other half of the clutch pack Surrounding the outside of the drum is a band that can be tightened around the drum when required to prevent the drum with the attached sun gear from turning The clutch pack is used in this instance to lock the planet carrier with the sun gear forcing both to turn at the same speed If both the clutch pack and the band were released the system would be in neutral Turning the input shaft would turn the planet gears against the sun gear but since noting is holding the sun gear it will just spin free and have no effect on the output shaft To place the unit in first gear the band is applied to hold the sun gear from moving To shift from first to high gear the band is released and the clutch is applied causing the output shaft to turn at the same speed as the input shaft Many more combinations are possible using two or more planetary sets connected in various way to provide the different forward speeds and reverse that are found in modern automatic transmission 2 Clutch pack A clutch pack consists of alternating disks that fit inside a clutch drum Half of the disks are steel and have splines that fit into groves on the inside of the drum The other half have a friction material bonded to their surface and have splines on the inside edge that fit groves on the outer surface of the adjoining hub There is a piston inside the drum that is activated by oil pressure at the appropriate time to squeeze the clutch pack together so that the two components become locked and turn as one 3 One way Clutch A one way clutch also known as a sprag clutch is a device that will allow a component such as ring gear to turn freely in one direction but not in the other This effect is just like that bicycle where the pedals will turn the wheel when pedaling forward but will spin free when pedaling backward A common place where a one way clutch is used is in first gear when the shifter is in the drive position When you begin to accelerate from a stop the transmission starts out in first gear But have you ever noticed what happens if you release the gas while it is still in first gear The vehicle continues to coast as if you were in neutral Now shift into Low gear instead of Drive When you let go of the gas in this case you will feel the engine slow 4 you down just like a standard shift car The reason for this is that in Drive one way clutch is used whereas in Low a clutch pack or a band is used 4 Torque Converter On automatic transmission the torque converter takes the place of the clutch found on standard shift vehicles It is there to allow the engine to continue running when the vehicle comes to a stop The principle behind a torque converter is like taking a fan that is plugged into the wall and blowing air into another fan which is unplugged If you grab the blade on the unplugged fan you are able to hold it from turning but as soon as you let go it will begin to speed up until it comes close to speed of the powered fan The difference with a torque converter is that instead of using air it used oil or transmission fluid to be more precise A torque converter is a lager doughnut shaped device that is mounted between the engine and the transmission It consists of three internal elements that work together to transmit power to the transmission The three elements of the torque converter are the pump the Turbine and the Stator The pump is mounted directly to the torque housing which in turn is bolted directly to the engine s crankshaft and turns at engine speed The turbine is inside the housing and is connected directly to the input shaft of the transmission providing power to move the vehicle The stator is mounted to a one way clutch so that it can spin freely in one direction but not in the other Each of the three elements has fins mounted in them to precisely direct the flow of oil through the converter With the engine running transmission fluid is pulled into the pump section and is pushed outward by centrifugal force until it reaches the turbine section which stars it running The fluid continues in a circular motion back towards the center of the turbine where it enters the stator If the turbine is moving considerably slower than the pump the fluid will make contact with the front of the stator fins which push the stator into the one way clutch and prevent it from turning With the stator stopped the fluid is directed by the stator fins to re enter the pump at a help angle providing a torque increase As the speed of the turbine catches up with the pump the fluid starts hitting the stator blades on the back side causing the stator to turn in the same direction as the pump and turbine As the speed increase all three elements begin to turn at approximately the same speed Sine the 80s in order to improve fuel economy torque converters have been equipped with a lockup clutch which locks the turbine to the pump as the vehicle reaches approximately 40 5 50 mph This lockup is controlled by computer and usually won t engage unless the transmission is in 3rd or 4th gear 5 Hydraulic System The hydraulic system is a complex maze of passage and tubes that sends that sends transmission fluid and under pressure to all parts of the transmission and torque converter and Transmission fluid serves a number of purpose including shift control general lubrication and transmission cooling Unlike the engine which uses oil primary for lubrication every aspect of a transmission s function is dependant on a constant supply of fluid is send pressure In order to keep the transmission at normal operating temperature a portion of the fluid is send to through one of two steel tubes to a special chamber that is submerged in anti freeze in the radiator Fluid passing through this chamber is cooled and then returned to the transmission through the other steel tube A typical transmission has an avenge of ten quarts of fluid between the transmission torque converter and cooler tank In fact most of the components of a transmission are constantly submerged in fluid including the clutch packs and bands The friction surfaces on these parts are designed to operate properly only when they are submerged in oil 6 Oil Pump The transmission oil pump not to confused with the pump element inside the torque converter is responsible for producing all the oil pressure that is required in the transmission The oil pump is mounted to front of the transmission case and is directly connected to a flange on the engine crankshaft the pump will produce pressure whenever the engine is running as there is a sufficient amount of transmission fluid available The oil enters the pump through a filter that is located at bottom of the transmission oil pan and travels up a pickup tube directly to the oil pump The oil is then sent under pressure to the pressure regulator the valve body and the rest of the components as required 7 Valve Body The valve body is the control center of the automatic transmission It contains a maze of channels and passages that direct hydraulic fluid to the numerous valves which when activate the appropriate clutch pack of band servo to smoothly shift to the appropriate gear for each driving situation For example the 2 3 shift valve activates the 2nd gear up shift or the 3 2 shift timing valve which determines when a downshift should occur The most important valve and the one that you have direct control over is the 6 manual valve The manual valve is directly connected to the gear shift handle and covers and uncovers various passages depending on what position the gear shift is paced in When you place the gear shift in Drive for instance the manual valve directs fluid to the clutch pack s that activates 1st gear It also sets up to monitor vehicle speed and throttle position so that it can determine the optimal time and the force for the 1 2 shift On computer controlled transmission you will also have electrical solenoids that are mounted in the valve body to direct fluid to the appropriate clutch packs or bands under computer control to more precisely control shift points 8 Seals and Gaskets An automatic transmission has many seals and gaskets to control the flow of hydraulic fluid and to keep it from leaking out There are two main external seals the front seal and the rear seal The front seal seals the point where the torque converter mounts to the transmission case This seal allows fluid to freely move from the converter to the transmission but keeps the fluid from leaking out The rear seal keeps fluid from leaking past the output shaft A seal is usually made of rubber similar to the rubber in a windshield wiper blade and is used to keep oil from leaking past a moving part such as a spinning shaft In some cases the rubber is assisted by a spring that holds he rubber in close contact with the spinning shaft A gasket is a type of seal used to seal two stationary parts that are fasted together Some common gasket materials are paper cork rubber silicone and soft metal Aside from the main seals there are also a number of other seals and gasket that vary from transmission to transmission A common example is the rubber O ring that seals the shaft for the shift control lever This is the shaft that you move when you manipulate the gear shifter Another example that is common to most transmission is the oil pan gasket In fact seals are required anywhere that a device needs to pass through the transmission case with each one being a potential source for leaks 9 Computer Controls The computer uses sensors on the engine and transmission to detect such things as throttle position vehicle speed engine speed engine load stop light switch position etc to control exact shift points as well as how soft or firm the shift should be Some computerized transmission even learn your driving style and constantly adapt to it so that 7 every shift is timed precisely when you would need it Because of computer controls sports models are coming out with the ability to take manual control of the transmission as through it were a stick shift lever through a special gate then tapping it in one direction or the other in order to up shift at will The computer monitors this activity to make sure that the driver dose not select a gear that could over speed the engine and damage it Another advantage to these smart transmission is that they have a self diagnostic mode which can detect a problem early on and warn you with an indicator light on the dash A technician can then plug test equipment in and retrieve a list of trouble codes that will help pinpoint where the problem is