畢業(yè)設(shè)計(jì)任務(wù)書(shū)學(xué)生姓名 學(xué)號(hào) 班 級(jí)指導(dǎo)教師 職稱(chēng) 單 位畢業(yè)設(shè)計(jì)題目 汽車(chē)前橋的設(shè)計(jì)畢業(yè)設(shè)計(jì)主要內(nèi)容和要求：前橋是汽車(chē)上一個(gè)重要的部分，主要包括轉(zhuǎn)向節(jié)，轉(zhuǎn)向主銷(xiāo)，前軸等零部件，由于汽車(chē)的行駛過(guò)程中，前橋所處的工作環(huán)境惡劣，工作情況復(fù)雜，其承受的載荷也多為交變載荷，從而其零部件也容易出現(xiàn)疲勞裂紋甚至斷裂現(xiàn)象。這就要求其在結(jié)構(gòu)上必須有足夠的強(qiáng)度、剛度和抗疲勞破壞的能力。車(chē)橋通過(guò)懸架與車(chē)架連接，支撐著汽車(chē)的大部分重量，并將車(chē)輪的牽引力或制動(dòng)力，以及側(cè)向力經(jīng)過(guò)懸架傳給車(chē)架。按照其使用功能劃分，車(chē)橋可以分為轉(zhuǎn)向橋、專(zhuān)項(xiàng)驅(qū)動(dòng)橋、驅(qū)動(dòng)橋和支撐橋。本次課題的主要內(nèi)容就是要設(shè)計(jì)一個(gè)結(jié)構(gòu)優(yōu)良的非驅(qū)動(dòng)橋，即轉(zhuǎn)向橋整車(chē)參數(shù)：汽車(chē)總質(zhì)量M（kg ）前橋軸載重量(N)G1汽車(chē)質(zhì)心至前橋中心線(xiàn)距離(mm)L1汽車(chē)質(zhì)心至后軸中心線(xiàn)距離(mm)2軸距L(mm)前輪距 B(mm)前鋼板彈簧座中心距s(mm)2500 8500 1800 1000 2800 1350 650主銷(xiāo)中心距 (mm)B1汽車(chē)質(zhì)心高度(mm)hg車(chē)輪滾動(dòng)半徑(mm)r主銷(xiāo)內(nèi)傾角β主銷(xiāo)后傾角γ前輪外傾角α前輪前束(mm)1200 850 350 6° 2° 1° 2畢業(yè)設(shè)計(jì)（論文）主要參考資料：[1]銀金光 王宏主編 機(jī)械設(shè)計(jì)課程設(shè)計(jì) 北京：中國(guó)林業(yè)出版社，2006[2] 黃余平主編.汽車(chē)構(gòu)造教學(xué)圖解.北京：人民交通出版社，2005[3] 濮良貴 紀(jì)明剛主編 機(jī)械設(shè)計(jì) 北京：高等教育出版社，2006[4] 肖永清 楊忠敏主編 汽車(chē)前橋及轉(zhuǎn)向系統(tǒng)結(jié)構(gòu)與維修 北京：國(guó)防工業(yè)出版社，2004[5] 劉濤 主編 汽車(chē)設(shè)計(jì) 北京：北京大學(xué)出版社，2000[6] 陳家瑞 主編 汽車(chē)構(gòu)造 北京：機(jī)械工業(yè)出版社，2005[7] 小林明 主編 汽車(chē)工程手冊(cè) 北京：機(jī)械工業(yè)出版社，1996[8] 成大先 主編 機(jī)械設(shè)計(jì)手冊(cè) 北京：化學(xué)工業(yè)出版社，1993畢業(yè)設(shè)計(jì)（論文）應(yīng)完成的主要工作：1、閱讀設(shè)計(jì)任務(wù)書(shū)，明確設(shè)計(jì)要求、工作條件、內(nèi)容和步驟；了解設(shè)計(jì)對(duì)象；閱讀有關(guān)資料，明確課程設(shè)計(jì)的方法和步驟，初步擬定設(shè)計(jì)計(jì)劃。2、根據(jù)任務(wù)書(shū)中所給參數(shù)和工作要求， 設(shè)計(jì)前橋整體結(jié)構(gòu)。3、通過(guò)設(shè)計(jì)計(jì)算，確定各零件的主要參數(shù)和尺寸，一般包括前軸、轉(zhuǎn)向節(jié)、轉(zhuǎn)向節(jié)臂，轉(zhuǎn)向節(jié)主銷(xiāo)等。4、繪制主要零部件的圖紙。畢業(yè)設(shè)計(jì)（論文）進(jìn)度安排：序號(hào) 畢業(yè)設(shè)計(jì)（論文）各階段內(nèi)容 時(shí)間安排 備注1 確定畢業(yè)設(shè)計(jì)題目，查閱并收集整理相關(guān)資料 2010.11.-2010.122 確定研究方法，分析處理數(shù)據(jù)，撰寫(xiě)論文大綱 2011.1-2011.23 構(gòu)思論文內(nèi)容，設(shè)計(jì)開(kāi)題報(bào)告，完成論文初稿的撰寫(xiě) 2011.3.-2011.44 論文修改潤(rùn)色，完成論文終稿，送交指導(dǎo)老師評(píng)審，進(jìn)行答辯 2011.4.-2011.5課題信息：課題性質(zhì)： 設(shè)計(jì)√ 論文□ 課題來(lái)源： 教學(xué)□ 科研□ 生產(chǎn)√ 其它□發(fā)出任務(wù)書(shū)日期： 指導(dǎo)教師簽名：年 月 日教研室意見(jiàn)：教研室主任簽名：年 月 日 學(xué)生簽名： 本 科 畢 業(yè) 設(shè) 計(jì) 外 文 資 料 翻 譯系 別：工程技術(shù)系 專(zhuān) 業(yè)：機(jī)械設(shè)計(jì)制造及其自動(dòng)化 姓 名：學(xué) 號(hào)：外文資料翻譯譯文前橋一般位于汽車(chē)的前部，也稱(chēng)轉(zhuǎn)向橋或從動(dòng)橋。前橋是汽車(chē)上一個(gè)重要的 總成件，主要包括轉(zhuǎn)向節(jié)、轉(zhuǎn)向主銷(xiāo)、前梁等零部件。前橋是通過(guò)懸架與車(chē)架相 連，用以承受地面與車(chē)架之間的垂直載荷外，還承受制動(dòng)力和側(cè)向力以及這些力 所構(gòu)成的力矩，并保證轉(zhuǎn)向輪作正確的運(yùn)動(dòng)。車(chē)橋通過(guò)懸架與車(chē)架連接，支撐著 汽車(chē)大部分重量， 并將車(chē)輪的牽引力或者制動(dòng)力， 以及側(cè)向力經(jīng)過(guò)懸架傳給車(chē)架。 在汽車(chē)使用中，轉(zhuǎn)向橋的受力狀況比較復(fù)雜，因此應(yīng)具有足夠的強(qiáng)度。為保證轉(zhuǎn) 向車(chē)輪的正確定位角度，使操縱輕便并減輕輪胎的磨耗，轉(zhuǎn)向橋也應(yīng)有足夠的剛 度。此外，還應(yīng)盡量減輕轉(zhuǎn)向橋的重量?？傊?，由于在汽車(chē)的行駛過(guò)程中，前橋 所處的工作環(huán)境惡劣，工況復(fù)雜，其承受的載荷也多為交變載荷，從而其零部件 易出現(xiàn)疲勞裂紋甚至斷裂現(xiàn)象。這就要求其在結(jié)構(gòu)設(shè)計(jì)上必須有足夠的強(qiáng)度、剛 度和抗疲勞破壞的能力。前軸：是前橋的主要承重零部件，我公司有管式和鍛打式兩種結(jié)構(gòu)形式，但 主要以鍛打式為主。前軸兩端各有一呈拳形的加粗部分作為安裝主銷(xiāo)的部位。中 間部分的兩側(cè)為板簧支座面，用以安裝鋼板板彈簧及其附件。 在此需要說(shuō)明的是： U 型螺栓穿過(guò)前軸的安裝孔需要打緊下方的背緊螺母 在 時(shí)，往往會(huì)出現(xiàn)套筒跟前軸背筋發(fā)生干涉的問(wèn)題。為什么會(huì)出現(xiàn)該問(wèn)題呢？一是 設(shè)計(jì)問(wèn)題，因?yàn)榍拜S的背筋影響到前橋的載荷，因此必須保證一定的尺寸要求， 而如果前后 U 型螺栓的距離設(shè)計(jì)的過(guò)小， 沒(méi)有留出足夠的間隙裝配便會(huì)出現(xiàn)以上 問(wèn)題。二是工藝問(wèn)題，工藝問(wèn)題有兩種情況。第一種是前軸背筋的對(duì)稱(chēng)度不好或 安裝孔的對(duì)稱(chēng)度不好容易造成該問(wèn)題； 第二種就是有些主機(jī)廠(chǎng)為避免套筒的易損， 沒(méi)有考慮到產(chǎn)品的實(shí)際情況而盲目加大套筒的外徑。 主銷(xiāo)：是影響整車(chē)性能的重要零部件。主銷(xiāo)上有止動(dòng)槽，銷(xiāo)鎖栓通過(guò)止動(dòng)槽將主銷(xiāo)固定在前軸的主銷(xiāo)孔內(nèi)，使其不能轉(zhuǎn)動(dòng)也不能軸向移動(dòng)。節(jié)銷(xiāo)的加工精度要求 很高，是我公司重點(diǎn)控制的零部件之一。 轉(zhuǎn)向節(jié)：轉(zhuǎn)向節(jié)是前橋上主要的轉(zhuǎn)向件。它利用主銷(xiāo)和前軸鉸接并經(jīng)一對(duì)輪轂軸 承承支撐著輪轂組合，來(lái)實(shí)現(xiàn)轉(zhuǎn)向的功能。 制動(dòng)器總成：是實(shí)現(xiàn)車(chē)輪制動(dòng)的主要元件，有油剎和氣剎兩種形式。在車(chē)輛實(shí)施 制動(dòng)命令時(shí)， 制動(dòng)器的摩擦片通過(guò)擴(kuò)張與制動(dòng)鼓的內(nèi)加工面接觸產(chǎn)生摩擦力實(shí)現(xiàn) 車(chē)輛制動(dòng)。前橋制動(dòng)器的選擇非常關(guān)鍵，如果選擇不當(dāng)，會(huì)出現(xiàn)前后制動(dòng)力不匹 配，制動(dòng)力達(dá)不到要求等許多問(wèn)題。 輪轂組合：主要通過(guò)兩滾動(dòng)軸承安裝在轉(zhuǎn)向節(jié)上，帶動(dòng)車(chē)輪轉(zhuǎn)動(dòng)。同時(shí)與摩擦片 形成摩擦副，實(shí)現(xiàn)車(chē)輪的制動(dòng)。 節(jié)臂：分直拉桿臂、橫拉桿臂，分別和直拉桿總成和橫拉桿總成相連。形成轉(zhuǎn)向 機(jī)構(gòu)和轉(zhuǎn)向梯形機(jī)構(gòu)。轉(zhuǎn)向機(jī)構(gòu)來(lái)完成車(chē)輛的轉(zhuǎn)向，轉(zhuǎn)向梯形決定了車(chē)輛的內(nèi)外 轉(zhuǎn)角是否合理。 橫拉桿總成：是調(diào)整前束的主要零部件。桿身是由無(wú)縫鋼管制造，兩端是球形鉸 接結(jié)構(gòu)的接頭總成，通過(guò)螺紋配合后安裝在橫拉桿臂上，桿身可調(diào)，以便于調(diào)節(jié) 前束。 前橋承受汽車(chē)的前部重量，把汽車(chē)的前進(jìn)推力從車(chē)架傳給車(chē)輪，并與轉(zhuǎn)向裝 置的有關(guān)機(jī)件作關(guān)節(jié)式聯(lián)系，實(shí)施汽車(chē)的轉(zhuǎn)向。前橋是利用它的兩端通過(guò)主銷(xiāo)與 轉(zhuǎn)向節(jié)連接，用以轉(zhuǎn)向節(jié)的擺轉(zhuǎn)來(lái)實(shí)現(xiàn)汽車(chē)的方向。為使汽車(chē)在行駛中具有較好的直線(xiàn)行駛能力，前橋應(yīng)滿(mǎn)足下列要求： 為使汽車(chē)在行駛中具有較好的直線(xiàn)行駛能力，前橋應(yīng)滿(mǎn)足下列要求： 1．足夠的強(qiáng)度，以保證可靠的承受車(chē)輪與車(chē)架（或承載式車(chē)身）之間的作 用力。 2．正確的車(chē)輪定位，使轉(zhuǎn)向輪運(yùn)動(dòng)穩(wěn)定，操縱輕便并減輕輪胎的磨損。前 輪定位包括主銷(xiāo)內(nèi)傾，主銷(xiāo)后傾，前輪外傾和前輪前束。 3．足夠的剛度，使受力后變形要小，保證主銷(xiāo)和轉(zhuǎn)向輪有正確的定位角度 保持不變。 4．轉(zhuǎn)向節(jié)與主銷(xiāo)，轉(zhuǎn)向節(jié)與前橋之間的摩擦力應(yīng)盡可能小，以保證轉(zhuǎn)向操 作的輕便性，并有足夠的耐磨性。 5．轉(zhuǎn)向輪的擺振應(yīng)盡可能小，以保證汽車(chē)的正常，穩(wěn)定行使。 6．前橋的質(zhì)量應(yīng)盡可能小，以減少非簧載質(zhì)量，提高汽車(chē)行駛平順性。1.微型汽車(chē)前軸 1.微型汽車(chē)前軸 微型汽車(chē)前懸架普遍采用了獨(dú)立懸架的結(jié)構(gòu)。前軸的載荷相對(duì)較小，結(jié)構(gòu)也 較為簡(jiǎn)單。微型汽車(chē)前軸一般多為斷開(kāi)式活動(dòng)關(guān)節(jié)的結(jié)構(gòu)，由前軸本體，左右橫 擺臂，加強(qiáng)桿臂等組成。 2.轎車(chē)前橋 2.轎車(chē)前橋 轎車(chē)前橋采用麥弗遜式懸架。它承擔(dān)著驅(qū)動(dòng)及轉(zhuǎn)向的雙重功能，懸架上端與 車(chē)身相連，下端與車(chē)輪軸承殼體相連，車(chē)輪的外傾是通過(guò)懸架與軸承殼體的連接 螺栓來(lái)調(diào)整的，副車(chē)架利用彈性件通過(guò)控制臂，球鉸與懸掛相連，提高了行駛的 穩(wěn)定性和乘坐的舒適性。 3.越野車(chē)前橋 3.越野車(chē)前橋越野汽車(chē)的前橋負(fù)有轉(zhuǎn)向和驅(qū)動(dòng)兩種任務(wù)，故稱(chēng)為轉(zhuǎn)向驅(qū)動(dòng)橋。它和一般驅(qū) 動(dòng)橋一樣，具有主傳動(dòng)器、差速器和半軸。不同之處是，由于轉(zhuǎn)向的需要，半軸 被分為內(nèi)，外兩段而用萬(wàn)向節(jié)連接起來(lái)，同時(shí)主銷(xiāo)也因而做成上下兩段。 4.載重汽車(chē)前軸 4.載重汽車(chē)前軸 載重汽車(chē)前軸采用工字形斷面主要用以提高前軸的抗彎強(qiáng)度。上部有二處加 寬平面，用以支承鋼板彈簧。前軸兩端各有一個(gè)拳形部分，其中有通孔，作為裝 轉(zhuǎn)向節(jié)主銷(xiāo)只用。主銷(xiāo)與左右轉(zhuǎn)向節(jié)鉸接，用帶有螺紋的楔形鎖銷(xiāo)橫穿過(guò)與主銷(xiāo) 孔垂直通孔，靠鎖銷(xiāo)楔面將主銷(xiāo)固定在前軸孔內(nèi)，使它不能轉(zhuǎn)動(dòng)。一般情況下，常見(jiàn)材料所需定義的材料特性包括：彈性模量、泊松比、密 度、比熱、熱膨脹系數(shù)等。前橋主要由兩部分材料組成，即前軸和轉(zhuǎn)向節(jié)等零部 件材料。前軸的材料采用 45 號(hào)鋼，轉(zhuǎn)向節(jié)的材料采用 40Cr。扭桿是汽車(chē)前獨(dú)立懸架中的關(guān)鍵件，屬細(xì)長(zhǎng)桿件，其感應(yīng)淬火處理是生產(chǎn)中的工藝難 點(diǎn)， 該文介紹了扭桿的淬火感應(yīng)器及其工藝試驗(yàn)結(jié)果， 確定采用半圈式感應(yīng)器連續(xù)淬火工藝， 這種處理方法能滿(mǎn)足扭桿技術(shù)要求和批量生產(chǎn)。該類(lèi)鍛件在鍛造成型時(shí)， 不僅需要較大的變形能， 而且尚需一定的變形力，因此選用 J53 系列雙盤(pán)摩擦壓力機(jī)比較經(jīng)濟(jì)，該系列壓力機(jī)采用組合打滑飛輪， 組合打滑飛輪既能為高度變形較大的鍛件提供足夠的交形能， 又能為鍛件提供必 需的變形力，且不致超負(fù)荷，該系列壓力機(jī)的設(shè)備投資、模具成本和鍛件成本均 比模鍛錘和熱模鍛曲柄壓力機(jī)便宜一半多。 目前，國(guó)內(nèi)汽車(chē)前軸機(jī)加工工藝流程主要有以下幾種： (1)①銑兩鋼板彈簧座平面；②鉆兩鋼板彈簧座平面十孔；③ 粗銑兩主銷(xiāo)孔 上下端面；④精銑主銷(xiāo)孔上下端面；⑤鉆擴(kuò)鉸主銷(xiāo)孔； ⑥拉削主銷(xiāo)孔；⑦锪主銷(xiāo) 孔上下端面；⑧鉆鉸鎖銷(xiāo)孔。在該方案中，存在以下問(wèn)題：① 采用主銷(xiāo)孔定位锪 上下端面，端面與主銷(xiāo)孔的垂直度不易保證，主銷(xiāo)孔高度尺寸不易保證；②以主 銷(xiāo)孔定位鉆鎖銷(xiāo)孔時(shí)，鉆頭經(jīng)過(guò)十字相貫孔時(shí)，易出現(xiàn)單邊切削現(xiàn)象，生偏移， 造成主銷(xiāo)孔與鎖銷(xiāo)孔中心距不易保證。 (2)①銑兩鋼板彈簧座平面；②鉆兩鋼板彈簧座平面十孔；③ 鉆鉸鎖銷(xiāo)孔一 ④粗銑主銷(xiāo)孔上下端面； ⑤精銑主銷(xiāo)孔上下端面； ⑥鉆擴(kuò)鉸主銷(xiāo)孔。 在該方案中， 存在以下問(wèn)題：①因該工藝方法是采用先鉆鎖銷(xiāo)孔后鉆主銷(xiāo)孔，而主銷(xiāo)-fL：fL 徑及位置尺寸為關(guān)鍵尺寸，主銷(xiāo)精度不易保證；② 采用先精銑主銷(xiāo)孔上下端面后 加工主銷(xiāo)孔，端面相對(duì)主銷(xiāo)孔的垂直度難以保證。 (3)①銑兩鋼板彈簧座平面；②鉆兩鋼板彈簧座平面十孔；③鉆鉸鎖銷(xiāo)孔； ④粗銑主銷(xiāo)上下端面；⑤鉆擴(kuò)鉸主銷(xiāo)孔；⑥ 精銑主銷(xiāo)孔上下端面。在該方案中， 存在以下問(wèn)題：①主銷(xiāo)孔與鎖銷(xiāo)孔十字相貫孔尺寸公差±0．1mm 不易保證；② 采用鉸削主銷(xiāo)孔，其尺寸公差不易保證；③最后精銑主銷(xiāo)孔上下端面。主銷(xiāo)孔與 上下端面垂直度不易保證；④主銷(xiāo)孔長(zhǎng)度尺寸不易保證。隨著我國(guó)交通運(yùn)輸事業(yè)的迅速發(fā)展， 汽車(chē)運(yùn)輸?shù)某休d重量和運(yùn)行速度都在不斷增 加。于是人們對(duì)汽車(chē)的安全運(yùn)行也越來(lái)越重視，所以對(duì)汽車(chē)車(chē)橋的設(shè)計(jì)也提出了 更高的要求。由于國(guó)外汽車(chē)發(fā)展起步早，技術(shù)投入大，因此在技術(shù)上遠(yuǎn)遠(yuǎn)領(lǐng)先國(guó) 內(nèi)市場(chǎng)，當(dāng)然也還有很多不足的地方，還需要改進(jìn)，技術(shù)也還需要有所突破。汽 車(chē)工業(yè)作為我國(guó)重點(diǎn)發(fā)展的支柱產(chǎn)業(yè)，其前景相當(dāng)廣闊。目前汽車(chē)零部件的生產(chǎn) 有一定的潛力，但大多數(shù)企業(yè)在產(chǎn)品研究，開(kāi)發(fā)等環(huán)節(jié)存在一定的欠缺，尤其缺 少產(chǎn)品的自主開(kāi)發(fā)能力，不能適應(yīng)系統(tǒng)配套，模塊供貨，難以參與國(guó)際分工。因 此，在今后的發(fā)展中，我國(guó)企業(yè)應(yīng)積極吸收國(guó)際汽車(chē)先進(jìn)技術(shù)，不斷完善自主體 系，如制動(dòng)系統(tǒng)，轉(zhuǎn)向系統(tǒng)等，擴(kuò)大該產(chǎn)業(yè)的產(chǎn)品品種，提高整體技術(shù)水平，增 強(qiáng)技術(shù)開(kāi)發(fā)能力，促使企業(yè)更快的發(fā)展，適應(yīng)汽車(chē)行業(yè)全球化趨勢(shì)。100 多年前，汽車(chē)剛剛誕生初期，其轉(zhuǎn)向操縱是仿照馬車(chē)和自行車(chē)的轉(zhuǎn)向方式，即用一個(gè)操縱桿或手柄來(lái)使前輪偏轉(zhuǎn)，從而實(shí)現(xiàn)轉(zhuǎn)向。由于操縱費(fèi)力且不可靠，以至于時(shí)常發(fā)生車(chē)毀人亡的事故。第一輛不用馬拉的四輪車(chē)問(wèn)世時(shí)，已經(jīng)把前橋和前輪組成一個(gè)總成，此總成安裝在曲軸上，可以繞前橋的中心的一個(gè)點(diǎn)轉(zhuǎn)動(dòng)，利用一個(gè)桿柱,連接前橋的重點(diǎn)，通過(guò)地板往上延伸，方向盤(pán)就緊固在桿柱上端，以此操縱汽車(chē)。這種裝置在汽車(chē)車(chē)速不超過(guò)馬車(chē)的速度時(shí)，還是很好使的，但當(dāng)車(chē)速提高后，駕駛員就要求提高轉(zhuǎn)向的準(zhǔn)確性，以減少輪胎的磨損，提高輪胎的使用壽命。1817 年，德國(guó)人林肯斯潘杰提出類(lèi)似于現(xiàn)代汽車(chē)、將前輪用轉(zhuǎn)向節(jié)與前梁連接的方式，他研制了一種允許汽車(chē)前輪在主軸上獨(dú)立回轉(zhuǎn)的結(jié)構(gòu)，這就是把車(chē)輪與轉(zhuǎn)向節(jié)連接起來(lái)，轉(zhuǎn)向節(jié)又用可轉(zhuǎn)動(dòng)的銷(xiāo)軸與前軸連接，從而發(fā)明了現(xiàn)代轉(zhuǎn)向梯形機(jī)構(gòu)。中國(guó)改革開(kāi)放以來(lái)，在農(nóng)村實(shí)行家庭聯(lián)產(chǎn)承包責(zé)任制的改革，使農(nóng)村的經(jīng)濟(jì)空前活躍。農(nóng)村的貨運(yùn)量和人口流動(dòng)量急劇增加，加快了運(yùn)輸機(jī)械化成為農(nóng)村經(jīng)濟(jì)發(fā)展的迫切需要，也正是這一市場(chǎng)的需要使具有中國(guó)特色的運(yùn)輸機(jī)械——小型載貨汽車(chē)的應(yīng)運(yùn)而生。它解決了農(nóng)村運(yùn)輸?shù)募毙?，填補(bǔ)了村際、鄉(xiāng)際，城鎮(zhèn)及城鄉(xiāng)結(jié)合部運(yùn)輸網(wǎng)絡(luò)的空白，活躍了農(nóng)村經(jīng)濟(jì)，為農(nóng)村富裕勞動(dòng)力找了一條出路，從而使數(shù)以萬(wàn)計(jì)的農(nóng)民走上了小康之路。小型載貨汽車(chē)制造工藝簡(jiǎn)單，價(jià)格便宜，購(gòu)車(chē)農(nóng)戶(hù)一般在一年左右就可收回成本。另外，公路的快速建設(shè)也促進(jìn)了小型載貨汽車(chē)的發(fā)展，目前全國(guó) 98%的鄉(xiāng)村都通上了公路，使得全國(guó)小型載貨汽車(chē)有了用武之地。我們要開(kāi)發(fā)的小型載貨汽車(chē)要多進(jìn)行優(yōu)化設(shè)計(jì)，使產(chǎn)品新穎化，品種多樣化以適應(yīng)多種需要。在小型載貨汽車(chē)的設(shè)計(jì)中，如何在復(fù)雜的路況下保證汽車(chē)能快速平穩(wěn)的行駛，就是一個(gè)重要問(wèn)題。于是就有了本課題的研究和設(shè)計(jì)。 汽車(chē)前橋是行駛系統(tǒng)的重要組成部分，它通過(guò)懸架與車(chē)架相連，兩端安裝汽車(chē)的轉(zhuǎn)向車(chē)輪，用于支持車(chē)架并傳遞車(chē)輪與車(chē)架之間的各種作用力，并驅(qū)使轉(zhuǎn)向節(jié)的擺動(dòng)來(lái)實(shí)現(xiàn)汽車(chē)的轉(zhuǎn)向。利用鉸鏈裝置使車(chē)輪偏轉(zhuǎn)一定角度，以實(shí)現(xiàn)車(chē)輛轉(zhuǎn)向的車(chē)橋稱(chēng)為轉(zhuǎn)向橋，一般汽車(chē)都以前橋?yàn)檗D(zhuǎn)向橋，本題前橋即為轉(zhuǎn)向橋。轉(zhuǎn)向橋不僅能使裝在前端的左右車(chē)輪偏轉(zhuǎn)一定的角度來(lái)實(shí)現(xiàn)轉(zhuǎn)向，還應(yīng)能承受垂直載荷和由道路、制動(dòng)等力產(chǎn)生的縱向力和側(cè)向力以及這些力所形成的力矩。因此，轉(zhuǎn)向橋必須有足夠的強(qiáng)度和剛度。車(chē)輪轉(zhuǎn)向過(guò)程中內(nèi)部件之間摩擦力應(yīng)該盡可能小，并且保證汽車(chē)轉(zhuǎn)向輕便和方向的穩(wěn)定性。轉(zhuǎn)向橋一般由前軸、轉(zhuǎn)向節(jié)、轉(zhuǎn)向節(jié)臂，轉(zhuǎn)向節(jié)主銷(xiāo)及輪轂組成。前橋一般位于汽車(chē)的前部，也稱(chēng)轉(zhuǎn)向橋或駕駛橋。是通過(guò)懸架與車(chē)架相連，用以承受地面與車(chē)架之間的垂直載荷外，還承受制動(dòng)力和側(cè)向力以及這些力構(gòu)成的力矩，并保證轉(zhuǎn)向輪作正確的運(yùn)動(dòng)。在汽車(chē)使用中，轉(zhuǎn)向橋的受力情況比較復(fù)雜，因此應(yīng)具有足夠的強(qiáng)度。為保證轉(zhuǎn)向車(chē)輪的正確定位角度，使操縱輕便并減輕輪胎的磨耗，轉(zhuǎn)向橋也應(yīng)有足夠的剛度。此外，還應(yīng)盡量減輕轉(zhuǎn)向橋的重量。前橋承受汽車(chē)的前部重量，把汽車(chē)的前進(jìn)推力從車(chē)架傳給車(chē)輪，并與轉(zhuǎn)向裝置的有關(guān)機(jī)件作關(guān)節(jié)式的聯(lián)系，實(shí)施汽車(chē)的轉(zhuǎn)向。越野汽車(chē)的前橋同時(shí)還承擔(dān)著與驅(qū)動(dòng)后橋同樣的驅(qū)動(dòng)任務(wù)。一般載貨汽車(chē)采用發(fā)動(dòng)機(jī)前置后橋驅(qū)動(dòng)的布置形式，故其前橋?yàn)檗D(zhuǎn)向橋。汽車(chē)前橋設(shè)計(jì)時(shí)應(yīng)保證有足夠的設(shè)計(jì)強(qiáng)度，以保證可靠的承受車(chē)輪與車(chē)架之間的作用力；保證有足夠的剛度，以使車(chē)輪定位參數(shù)不變；保證轉(zhuǎn)向輪有正確的定位角度，以使轉(zhuǎn)向輪運(yùn)動(dòng)穩(wěn)定，操縱輕便并減輕輪胎的摩擦；轉(zhuǎn)向橋的質(zhì)量盡量小，以減輕非簧上質(zhì)量，提高汽車(chē)行駛平順性。外文原文Front axle general is in the front of the bus, also known as steering axle or drive bridge. Automobile front axle is the last important assemblies, including the steering knuckle kingpin, steering, front beam and other components. Front axle through the suspension and frame, used to support the ground and the frame between the vertical load, but also bear the braking force and lateral force and the force of torque, and ensure that the steering rotation right movement. The axle is connected with the frame through the suspension, support most of the weight of vehicle, and wheel traction or braking force, as well as the lateral force after suspension to frame. In the car used in the steering bridge, the stress condition is more complex, so it should have enough strength. In order to ensure the wheel turns to the correct positioning of angle, make manipulation of light and reduce tire wear, steering bridge should have enough stiffness. In addition, should also try to reduce the weight of the bridge. In short, because of the automobile in the running process of the front axle, the abominable working environment, complicated working condition, the load is alternating load, thus the parts easy to fatigue cracking and even rupture phenomenon. This requires that the structural design must have enough strength, stiffness and resistance to fatigue failure of the ability.The front axle is the main load-bearing parts: the front axle, my company has a tubular and forging type two structural forms, but mainly to forging type mainly. The front ends of each with a fist shape bold part as the kingpin of the site installation. In both sides of the spring support for partial surface, used for the installation of steel plate spring and accessories. Need note here is: U type bolt passes through the front mounting holes need matter beneath the back nut in, often can appear with the front axle sleeve back band interference problem. Why can appear such problem? Design is a problem, because the front dorsal ribs affects front axle load, therefore must have a certain size requirements, and if both before and after the U bolt distance design is too small, not enough gap assembly will appear above problem. Two technical problems, technical problems in two cases. The first is the front dorsal rib symmetry is not good or mounting hole symmetrical degree and easy to cause the problem; the second is that some host plant in order to avoid the vulnerable, without taking into account the reality of the product and blind to the sleeve outer diameter. Kingpin: is the impact of vehicle performance of main parts. Kingpin has stop groove, pin lock bolt through the stop groove masterPin fixed on the front axle kingpin bore, so that it can't move can not move axially. Knuckle pin machining accuracy is very high, my company is one of the parts of key control. Steering knuckle: steering knuckle is the main steering part of front axle. It uses the main pin and the front axle is hinged by a pair of axle bearing supporting hub combination, to achieve the function of turning. Brake assembly: is the realization of the wheel brake main component, a brake oil and gas brake two forms. Implemented in the vehicle brake command, brake friction plate through the expansion and brake drum machining surface contact friction realization of vehicle brake. Front axle brake option is very critical, if the choice is undeserved, can appear before and after the brake force is not a match, the braking force is not up to the requirements of many problems. Hub combination : by two rolling bearings mounted on the steering knuckle, drive the rotation of the wheels. At the same time with the friction plate to form a friction pair, to realize the brake wheel. Arm: straight rod arm, tie rod arm, respectively, and a straight rod assembly and the tie rod assembly. Formed a steering mechanism and a steering trapezoidal mechanism. The steering mechanism to complete the vehicle steering, steering trapezoid determines the vehicle inside and outside corner is reasonable. The tie rod assembly: is to adjust the beam before the main parts. The rod body is made of seamless steel tube manufacturing, both ends of the spherical hinge joint structure is the joint assembly, by a thread after the installation of the tie rod arm, the rod body is adjustable, so as to adjust the toe. Front axle under the front of the car weight, the car forward thrust from the frame to the wheel, and with the steering device arranged on parts make joint type connection, the implementation of the automobile steering. The front axle is the use of both ends of it through the main pin and the steering knuckle is connected to the steering knuckle, swing to realize vehicle direction.In order to make the running vehicle has good linear driving ability, front axle should meet the following requirements: in order to make the running vehicle has good linear driving ability, front axle should meet the following requirements:1sufficient strength, in order to ensure the reliable bearing wheel and frame ( or monocoque ) between the work force. 2 correct positioning of the wheels, so that the steering wheel movement stability, convenient operation and reduce tire wear. Front wheel positioning includes kingpin inclination, caster, camber and toe-in. 3sufficient rigidity, the force deformation small, ensure the main pin and a steering wheel positioned right angle remains constant. 4knuckle and master pin, steering and front axle between the friction should be as small as possible, to ensure that the steering operation for portability, and has sufficient abrasion resistance. 5 steering wheel shimmy should be as small as possible, in order to ensure the vehicle normal, stable exercise. 6 front axle quality should be as small as possible, in order to reduce unsprung mass, improve vehicle ride comfort.1mini car front axle 1mini car front mini car front suspension generally adopt the independent suspension structure. Front axle load is relatively small, the structure is simple. Mini car front axle usually disconnected movable joint structure, which is composed of a front axle body, strengthen the transverse swing arm, arm etc 2 car front axle2 car front axle front axle suspension with Mcpherson car. It bears the driving and steering functions, the suspension is connected with the vehicle body, and the lower end of the wheel bearing housing connected, wheel camber is through the suspension and the bearing shell of the connecting bolt to adjust, auxiliary frame through the elastic part by controlling the arm, ball hinge connected with suspension, improve the driving stability and ride comfort. 3off-road vehicle front axle3off-road vehicle front axleOff-road vehicle steering and driving front axle has two tasks, it is known as the steering driving axle. And it generally drive the movable bridge, with a main driver, differential and the axle shaft. The difference is, due to the need, half shaft is divided into two segments, and by a universal joint, while the main pin are made under paragraph two. The 4truck front axle 4truck front axle truck front axle with I-shaped cross section is mainly used to improve the front bending strength. The upper two plus wide plane, to support the steel plate spring. The front ends each having a fist shape portion, which has a through hole, as a kingpin only. Main pin and left steering knuckle hinge, with a threaded wedge pin crossed with the main pin hole of vertical through holes on the lock pin wedge surface, the main pin is fixed in the axle hole, so that it cannot rotate.In general, common material needed to define the material properties including: elastic modulus, Poisson's ratio, density, specific heat, thermal expansion coefficient. The front axle is mainly composed of two parts, material composition, i.e., front axle and steering knuckle such as zero Department of materials. The front axle is adopted as the material of45 steel, steering knuckle materials using 40Cr.Torsion bar of automobile front independent suspension is the key component, is a slender rod, the induction quenching process is the manufacturing process difficult point, this paper introduces the torsion bar quenching inductor and its process test results, determined using half ring type inductor continuous quenching technology, this method can meet the technical requirements and the quantities of torsion bar production.The forging forging molding, not only greater deformation, but also requires a certain deformation force,Therefore the selection of J53series double disc friction press comparative economics, this series press combined slipping flywheel, combined slipping flywheel can provide highly deformed large forgings with enough to form, and can provide for forgings will required deformation capacity, and not to overload, the series press equipment investment, the cost of the mold and forging cost than die forging hammer and the forging crank press cheap cheap host. At present, the domestic automobile front axle machining process are the following: (1) of two plane milling plate spring seat; the drill two spring seat plane ten holes; the rough milling of two main pin hole of upper and lower end surfaces; the fine mill main pin hole of upper and lower end surfaces; the drilling and reaming main pin hole; the broaching the main pin hole; the main pin hole on the lower end of the countersink reaming pin holes;. In this scheme, the following questionQuestions:1 adopting main pin hole positioning countersink on the lower end, and the end surface of the main pin hole verticality can not be guaranteed, the main pin hole size height can not be guaranteed to the main pin hole; the positioning of the drill pin hole, drill through the cross intersection holes, easy cutting phenomenon, students offset, causing the main pin hole and the locking pin hole center distance can not be guaranteed. (2) of two plane milling plate spring seat; the drill two spring seat plane ten holes; the drilling and reaming pin holes on the rough milling of a main pin hole on upper end; the fine mill main pin hole of upper and lower end surfaces; the drilling and reaming main pin hole. In this scheme, there are the following problems: the process is used to drill the locking pin hole after the drill main pin hole, and the pin - fL: fL size and position size is the key size, kingpin is difficult to ensure the accuracy of the first; fine mill main pin hole of the upper and lower ends after processing the main pin hole, end relative to the main pin hole verticality is difficult to guarantee. (3) of two plane milling plate spring seat; the drill two spring seat plane ten holes; the drilling and reaming pin holes; the rough milling kingpin on upper end; the drilling and reaming main pin hole; the fine mill main pin hole on the lower end surface. In this scheme, there are the following problems : the main pin hole and the pin hole cross intersecting hole size tolerance of0.1mm is not easy to maintain; to adopt the reaming main pin hole, the dimensional tolerances are not easy to be ensured; the final finish milling main pin hole on the lower end surface. The main pin hole and upper and lower end verticality is not easy to guarantee; the main pin hole size can not be guaranteed.Along with our country transportation enterprise rapid development, auto transport carrying capacity and running speed are continually increasing with. So people to the safe operation of the automobile is more and more attention, so the automobile axle design also raised taller requirement. As a result of foreign automobile development starts early, technical inputs, thus technically far ahead of China market, but also there are many insufficient places, still need to improve, technology also needs a breakthrough. Steam car industry as our focus on the development of pillar industries, its prospect is very wide. At present, auto parts production has certain potential, but most enterprises in product research, development and other aspects of the defect, especially lack of less product independent development capacity, can not adapt to the system support, delivery of modules, to participate in international division of labor. Because of this, in the future development, Chinese enterprises should actively absorb the international advanced automotive technology, and constantly improve the self body lines, such as braking systems, steering systems, expand the industry of product variety, improve the integral technology level, increase the strong technological development capability, urges the enterprise faster development, adapt to the trend of globalization of automobile industry.100 years ago, the car was just beginning, the steering is modelled on the carriage and bicycle steering mode, using a joystick or a handle to make the front wheel deflection, thus realizes the steering. Due to the manipulation of effort and unreliable, so often fatal accident. The first horseless pull four wheel vehicle comes out, have a front axle and a front wheel assembly, the assembly being mounted on the crankshaft, front axle center around a point of rotation, using a rod connecting the front axle, focus, through the floor and extends upward, the wheel is fastened on the rod end, in order to manipulate the car. This device in a vehicle speed not exceeding the speed, or very good, but when the vehicle speed is increased, the driver asks to improve steering accuracy, in order to reduce tire wear, prolong the service life of tyre. In 1817, the Germans Lincoln Spang Jay presented similar to the modern automobile, the front wheel with knuckle and beam connection, he developed a kind of automobile front wheel on the main shaft to allow independent rotary structure, which is connected with the steering wheel, steering knuckle and a rotatable pin and front axle, thereby the invention of modern steering trapezoidal mechanism.Since China's reform and opening up, execute in the country the household contract responsibility system reform, make the rural economy is all-time and active. Rural freight traffic and population flow increased dramatically, speeding up the transportation mechanization into rural classicsEconomic development urgent need, it is also the needs of the market that has Chinese distinguishing feature of transport machinery -- emerge as the times require small truck. It has solved the countryside transportation need, fill the villages, townships, towns and urban transportation network is blank, active rural economics, for the surplus rural labor force to find a way out, so that tens of thousands of farmers to be on comparatively well-off road.Small truck manufacturing process is simple, cheap, purchase a car farmers generally in a year or so we can recover the cost. In addition, the highway construction has promoted the rapid development of small truck, the98% villages are on the road, so that the small truck with play.We want to develop a small truck to optimize the design, to make new