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車輛專業(yè)課程設(shè)計說明

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車輛專業(yè)課程設(shè)計說明目錄
1.概述···············································································1
1.1 整車總布置設(shè)計的任務(wù)··························································2
1.2 設(shè)計原則、目標(biāo)································································2
1.3設(shè)計方案的擬定································································2
2.整車型式的選擇·····································································3
2.1汽車軸數(shù)和驅(qū)動形式····························································3
2.2發(fā)動機的種類和型式····························································3
2.3車頭、駕駛室的型式····························································4
2.4輪胎的選擇····································································4
3.汽車主要參數(shù)的選擇·································································5
3.1主要尺寸參數(shù)的選擇····························································5
3.1.1軸距L···································································5
3.1.2前輪距B1和后輪距B2····················································5
3.1.3汽車的外廓尺寸···························································6
3.1.4前懸和后懸·························································6
3.2整車質(zhì)量參數(shù)估算······························································7
3.2.1空車狀態(tài)下整車質(zhì)量·······················································7
3.2.2汽車的軸荷分配···························································7
3.3主要性能參數(shù)的選擇····························································7
3.3.1動力性參數(shù)······························································9
3.3.2燃料經(jīng)濟性參數(shù)··························································10
3.3.3機動性參數(shù)······························································10
3.3.4汽車的操縱穩(wěn)定性參數(shù)····················································11
3.3.5行駛平順性參數(shù)··························································11
3.3.6制動性參數(shù)······························································12
3.3.7通過性參數(shù)·····························································12
4.發(fā)動機選型········································································14
4.1 發(fā)動機最大功率及其相應(yīng)轉(zhuǎn)速···········································14
4.2 發(fā)動機最大轉(zhuǎn)矩及其相應(yīng)轉(zhuǎn)速··········································15
4.3 發(fā)動機適應(yīng)性系數(shù)φ···························································16
5.輪胎的選擇········································································17
6.汽車總布置圖的繪制································································18
6.1 搜集和繪制有關(guān)總成、部件的外形圖··············································18
6.2 基準(zhǔn)線的選擇及其畫法·························································18
6.3 車廂及駕駛室的布置···························································19
6.4 發(fā)動機與離合器及變速器的布置·················································20
6.5 轉(zhuǎn)向系、操縱踏板及儀表板的布置················································20
6.6 車身底板的布置·······························································21
6.7 前后懸架的布置·······························································21
6.8 制動系的布置·································································21
6.9 油箱、備胎和行李箱等的布置····················································22
6.10軸荷分配和質(zhì)心位置的計算····················································22
7.設(shè)計小結(jié)··········································································23
參考文獻·········································································24

汽車總體設(shè)計
1.概述
汽車設(shè)計的內(nèi)容包括整車總體設(shè)計、總成設(shè)計和零件設(shè)計。整車總體設(shè)計又稱為汽車的總布置設(shè)計，其任務(wù)是使所設(shè)計的產(chǎn)品達到設(shè)計任務(wù)書所規(guī)定的整車參數(shù)和性能指標(biāo)的要求，并將這些整車參數(shù)和性能指標(biāo)分解為有關(guān)總成的參數(shù)和功能。解決人車之間的聯(lián)系問題屬于人機工程設(shè)計，它在汽車設(shè)計工作中占有極重要的位置。例如：駕駛操作空間尺寸的布置，車內(nèi)乘客空間尺寸的布置，座椅尺寸參數(shù)與特性參數(shù)的選擇，車身的外觀造型與色彩，儀表板的造型及儀表的選型與布置，車身內(nèi)飾材料與色彩的選擇，汽車的駕駛視野，汽車的駕駛性能與乘坐性能等，這些與人的感覺與視覺有直接聯(lián)系的方方面面，都會對汽車產(chǎn)品的設(shè)計質(zhì)量、品位和市場競爭力產(chǎn)生巨大的影響。
汽車是一個系統(tǒng)，這是基于汽車只有如下屬性而具備組成系統(tǒng)的條件：
(1)汽車是由多個要素（子系統(tǒng)及連接零件）組成的整體，每個要素對整體的行為有影響；
(2)組成汽車的各要素對整體行為的影響不是獨立的；
(3)汽車的行為不是組成它的任何要素所能具有的。
由此，汽車具備系統(tǒng)的屬性，對環(huán)境表現(xiàn)出整體性、一輛子系統(tǒng)屬性匹配協(xié)調(diào)的汽車所具備的功能大于組成它的各子系統(tǒng)功能純粹的、簡單的總和、反之，如果子系統(tǒng)的屬性因無序而相互干擾，即便是個體性能優(yōu)良的子系統(tǒng)，其功能也會因相互扼制而抵消，功率循環(huán)、軸轉(zhuǎn)向等就是這樣的典型例子。
系統(tǒng)論所揭示的系統(tǒng)整體性和系統(tǒng)功能的等級性必然會映射到設(shè)計任務(wù)中來、用整體性來解釋汽車設(shè)計的終極目標(biāo)是整車性能的綜合優(yōu)化，道理是十分顯然的、汽車設(shè)計任務(wù)的等級形態(tài)表現(xiàn)為：上位設(shè)計任務(wù)是確定下位設(shè)計任務(wù)要實現(xiàn)的目標(biāo)，下位設(shè)計是實現(xiàn)上位設(shè)計功能的手段、上、下位體系可從總體設(shè)計逐級分至零件設(shè)計，總體設(shè)計無疑處于這種體系的最上位，設(shè)計子系統(tǒng)的全部活動必須在總體設(shè)計構(gòu)建的框架內(nèi)進行、子系統(tǒng)設(shè)計固然重要，但統(tǒng)攬全局、設(shè)計子系統(tǒng)組合和相互作用體系規(guī)則的總體設(shè)計對汽車的性能和質(zhì)量的影響更加廣泛、更為深刻。
1.1 整車總布置設(shè)計的任務(wù)
(1) 從技術(shù)先進性、生產(chǎn)合理性和使用要求出發(fā)，正確選擇性能指標(biāo)、質(zhì)量和主要尺寸參數(shù)，提出總體設(shè)計方案，為各部件設(shè)計提供整車參數(shù)和設(shè)計要求；
(2) 對各部件進行合理布置和運動校核；
(3) 對整車性能進行計算和控制，保證汽車主要性能指標(biāo)實現(xiàn)；
(4) 協(xié)調(diào)好整車與總成之間的匹配關(guān)系，配合總成完成布置設(shè)計，使整車的性能、可靠性達到設(shè)計要求。
1.2 設(shè)計原則、目標(biāo)
(1)汽車的選型應(yīng)根據(jù)汽車型譜、市場需求、產(chǎn)品的技術(shù)發(fā)展趨勢和企業(yè)的產(chǎn)品發(fā)展規(guī)劃進行；
(2)選型應(yīng)在對同類型產(chǎn)品進行深入的市場調(diào)查、使用調(diào)查、生產(chǎn)工藝調(diào)查、樣車結(jié)構(gòu)分析與性能分析及全面的技術(shù)、進行分析的基礎(chǔ)上進行；
(3)應(yīng)從已有的基礎(chǔ)出發(fā)，對原有車型和引進的樣車進行分析比較，繼承優(yōu)點，消除缺陷，采用已有且成熟可靠的先進技術(shù)與結(jié)構(gòu)，開發(fā)新車型；
(4)涉及應(yīng)遵守有關(guān)標(biāo)準(zhǔn)、規(guī)范、法規(guī)、法律，不得侵犯他人專利；
(5)力求零件標(biāo)準(zhǔn)化、部件通用化、產(chǎn)品系列化。
1.3設(shè)計方案的擬定
(1)調(diào)查研究與初始決策：選定設(shè)計目標(biāo)，并制定產(chǎn)品設(shè)計工作及方針原則；
(2)總體方案設(shè)計：根據(jù)所選定的目標(biāo)及對開發(fā)目標(biāo)制定的工作方針、設(shè)計原則等主導(dǎo)思想提出整車設(shè)想；
(3)繪制總布置草圖，確定整車主要尺寸、質(zhì)量參數(shù)與性能以及各總成的基本形式；
(4)編寫設(shè)計任務(wù)書；
(5)汽車總布置設(shè)計；
(6)總成設(shè)計。
2. 整車型式的選擇
根據(jù)設(shè)計原則，目標(biāo)和用戶的需求特點，整車設(shè)計人員要提出被開發(fā)車型的整車型式方案，主要包括以下幾部分：
(1)發(fā)動機的種類和型式；
(2)軸數(shù)和驅(qū)動型式；
(3)車頭和駕駛室的型式及與發(fā)動機、前軸(輪)的位置關(guān)系；
(4)輪胎的選擇。
2.1汽車軸數(shù)和驅(qū)動形式
不同類型的汽車有不同的軸數(shù)和驅(qū)動型式，這主要根據(jù)使用條件、用途、工廠的生產(chǎn)條件、制造成本及公路的軸荷限值等因素進行選擇。汽車可以有兩軸、三軸、四軸甚至更多的軸數(shù)。影響選取軸數(shù)的因素主要有汽車的總質(zhì)量、道路法規(guī)對軸載質(zhì)量的限制和輪胎的負荷能力以及汽車的結(jié)構(gòu)等。最常用的是兩軸、后驅(qū)動4×2式汽車，其中轎車還可以采用4×2前驅(qū)動式結(jié)構(gòu)。對于一般總重小于 19t的汽車，都采用4×2后驅(qū)動的布置型式，因為這種汽車結(jié)構(gòu)簡單、布置合理、機動性好、成本低、適合于公路使用，是—種典型的、成熟的結(jié)構(gòu)型式。
2.2發(fā)動機的種類和型式
至今世界上絕大多數(shù)的汽車都是采用往復(fù)活塞式內(nèi)燃機，其中絕大多數(shù)的轎車采用汽油機。根據(jù)發(fā)動機氣缸排列形式不同，發(fā)動機有直列、水平對置和V型三種。氣缸直列式排列具有結(jié)構(gòu)簡單、寬度窄、布置方便等優(yōu)點。但當(dāng)發(fā)動機缸數(shù)多時，長度尺寸過長，在汽車上布置困難，因此直列式適用于6缸以下的發(fā)動機。此外，直列式還有高度尺寸大的缺點。
根據(jù)發(fā)動機冷卻方式不同，發(fā)動機分為水冷與風(fēng)冷兩種。大部分汽車用水冷發(fā)動機，因為它具有冷卻均勻可靠、散熱良好、噪聲小和能解決車內(nèi)供暖問題，以及加大散熱器面積后，能較好適應(yīng)發(fā)動機增壓后散熱的需要等優(yōu)點。水冷發(fā)動機的主要缺點是冷卻系結(jié)構(gòu)復(fù)雜；使用與維修不方便；冷卻性能受環(huán)境溫度影響較大。選取發(fā)動機的冷卻方式為水冷。
2.3車頭、駕駛室的型式
車頭、駕駛室的型式是汽車的最主要的型式之一。其選擇主要決定于用戶的要求、安全性、維修保養(yǎng)的方便性和生產(chǎn)條件等因素。
2.4輪胎的選擇
輪胎的尺寸和型號是進行汽車性能計算和繪制總布置圖的重要原始數(shù)據(jù)之一，選擇的依據(jù)是車型、使用條件、輪胎的靜負荷、輪胎的額定負荷以及汽車的行駛速度。當(dāng)然還應(yīng)考慮與動力—傳動系參數(shù)的匹配以及對整車尺寸參數(shù)(例如汽車的最小離地間隙、總高等)的影響。...

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