新能源電動(dòng)車驅(qū)動(dòng)橋設(shè)計(jì)【含CAD圖紙、說(shuō)明書】【QX系列】
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電動(dòng)車驅(qū)動(dòng)橋設(shè)計(jì)說(shuō)明書2018年04月目 錄摘要關(guān)鍵詞AbstractKey words1緒論11.1引言11.2電動(dòng)車的發(fā)展趨勢(shì)11.3 電動(dòng)車驅(qū)動(dòng)系統(tǒng)組成12電動(dòng)車總體設(shè)計(jì) 32.1 技術(shù)參數(shù)32.2 構(gòu)造形式及工作條件32.3主要參數(shù)選擇32.3.1 主要尺寸32.3.2 電動(dòng)車質(zhì)量32.3.3 電動(dòng)機(jī)參數(shù)32.3.4 輪胎參數(shù)42.3.5 傳動(dòng)比計(jì)算42.3.6 最大爬坡度計(jì)算42.4 核心件參數(shù)42.5 總體布置計(jì)算52.5.1 各部分質(zhì)量及重心坐標(biāo)52.5.2 空載及滿載時(shí)重心坐標(biāo)52.5.3 軸荷分配計(jì)算52.6 穩(wěn)定性計(jì)算 62.6.1 汽車不縱向翻倒的條件62.6.2 汽車不橫向翻倒的條件62.7 最小轉(zhuǎn)彎直徑的計(jì)算62.8 行程計(jì)算73 雙電動(dòng)機(jī)驅(qū)動(dòng)橋設(shè)計(jì)83.1 驅(qū)動(dòng)系統(tǒng)總體設(shè)計(jì)83.2 減速器的設(shè)計(jì)83.2.1傳動(dòng)比分配83.2.2 運(yùn)動(dòng)和動(dòng)力參數(shù)計(jì)算83.2.3 齒輪參數(shù)計(jì)算93.2.4 軸的設(shè)計(jì)193.2.5 平鍵的強(qiáng)度校核203.2.6 軸的強(qiáng)度校核203.2.7 軸承的壽命校核253.2.8 減速器箱體的設(shè)計(jì)273.3 半軸的設(shè)計(jì) 273.3.1 半軸的形式273.3.2 半軸軸徑的確定283.3.3 花鍵的設(shè)計(jì)和校核283.3.4 半軸連接螺釘強(qiáng)度校核293.4 輪轂的設(shè)計(jì)293.4.1 輪轂的外形設(shè)計(jì)293.4.2 輪轂與輪輞的連接螺栓強(qiáng)度校核293.5 驅(qū)動(dòng)橋殼的設(shè)計(jì)303.5.1 驅(qū)動(dòng)橋殼的結(jié)構(gòu)設(shè)計(jì)303.5.2 驅(qū)動(dòng)橋殼的強(qiáng)度計(jì)算303.5.3 橋殼與減速器連接螺釘強(qiáng)度校核333.6 輪轂軸承的壽命計(jì)算33致謝35參考文獻(xiàn)36附錄37摘要: 總體方案設(shè)計(jì)包括:分析給定的技術(shù)參數(shù)及工作條件,進(jìn)行調(diào)查研究、收集資料,確定個(gè)部分的構(gòu)造型式、主要尺寸及估重,并做布置位置草圖;初算整機(jī)重心位置、橋負(fù)荷、穩(wěn)定性、牽引性、制動(dòng)性、機(jī)動(dòng)性等,繪制總體外型尺寸及參數(shù)性能圖。驅(qū)動(dòng)系統(tǒng)設(shè)計(jì)包括:驅(qū)動(dòng)系統(tǒng)傳動(dòng)方案的確定。采用單電機(jī)集中驅(qū)動(dòng)系統(tǒng),由減速箱總成、差速器總成及驅(qū)動(dòng)橋組成,驅(qū)動(dòng)電機(jī)與減速器主動(dòng)齒輪直接相連,通過(guò)兩級(jí)減速及差速器,將扭矩傳送到左右兩個(gè)驅(qū)動(dòng)輪。電機(jī)軸線與車輪軸線平行,因此減速器采用兩極圓柱齒輪傳動(dòng)。半軸采用全浮式結(jié)構(gòu),與輪轂用螺釘連接傳遞轉(zhuǎn)矩。橋殼采用組合式結(jié)構(gòu),一端由輪轂軸承支承在車輪上,另一端與減速器相連。減速器的設(shè)計(jì)。分配傳動(dòng)比,計(jì)算動(dòng)力和運(yùn)動(dòng)參數(shù);按接觸強(qiáng)度確定中心距,計(jì)算齒輪的主要參數(shù);按扭轉(zhuǎn)強(qiáng)度設(shè)計(jì)軸的尺寸,按彎扭合成校核軸的強(qiáng)度;減速器箱體的設(shè)計(jì);軸承的壽命校核。半軸、橋殼等零件的結(jié)構(gòu)設(shè)計(jì)與強(qiáng)度校核。關(guān)鍵詞:電動(dòng)車;驅(qū)動(dòng)橋;減速器 Abstract: The collectivity design includes: Analyzing with the technical parameters and conditions of work which is given, surveying and collecting information, identifying the structure type, size and major, then the general layout could be done. Those barycentric coordinates, burthen of transaxle, stability, tractive effort, brakeage and maneuverability and so on will be calculating. The arrangement plan will be drawn. Transaxle design includes: Transaxle concept design is completed: the system consists of only a traction motor , gear reducer, diff and transaxle. Drive motor and gear reducer are directly linked to the initiative. The torque will be sent to driving wheels through the slowdown and the diff. As the axis of the motor parallels to the axis of the wheel, the reducer must be parallel shaft reducer. The gearing is full-floating axle shaft, which transfers torque with integral hub by screw. Axle housing must be unitized carrier-type axle housing, with one end bears on the wheel; the other end connects with the reducer. The design of reducer. Distribution of transmission ratio, computing parameters of power and motion; contacting center distance by strength identified, calculating parameters of the main gear, designing the size of axes; the design of reducer box; checking bearing life. The structure design and strength check of the axle, bridges and other parts of spare.Key words: Electric Vehicle;Transaxle;Reducer1 緒論1.1 引言伴隨著21世紀(jì)的到來(lái),由于降低公害、安全節(jié)能及新穎化的社會(huì)要求,汽車技術(shù)在不斷引入以新材料、電子技術(shù)為基礎(chǔ)的新技術(shù)過(guò)程中取得巨大的進(jìn)步。汽車能源利用效率、有害物排放、車用新能源的開(kāi)發(fā)和利用等問(wèn)題,近年來(lái)一直受到各國(guó)政府、專家和公眾的關(guān)注。人們投入巨額資金和大量人力研究更加清潔的電動(dòng)汽車,電動(dòng)汽車已經(jīng)成為各大汽車企業(yè)競(jìng)相研究開(kāi)發(fā)的前沿項(xiàng)目。1.2電動(dòng)車的發(fā)展趨勢(shì)電動(dòng)汽車是最近這些年來(lái)世界各大汽車廠競(jìng)相開(kāi)發(fā)的項(xiàng)目,因?yàn)榍鍧嵀h(huán)保汽車一直是人們追求的目標(biāo)。隨著人類對(duì)地球升溫的擔(dān)心和大氣污染的日益加重,人們對(duì)太陽(yáng)能的關(guān)心越來(lái)越增長(zhǎng)。電動(dòng)汽車的驅(qū)動(dòng)橋處于傳動(dòng)系的末端,它的基本功用是增大由傳動(dòng)器傳來(lái)的轉(zhuǎn)矩,將轉(zhuǎn)矩分配給左右驅(qū)動(dòng)車輪,并使左右驅(qū)動(dòng)車輪具有汽車行駛運(yùn)動(dòng)學(xué)所要求的差速功能;同時(shí),驅(qū)動(dòng)橋還要承受作用于路面和車架之間的鉛垂力、縱向力和橫向力。轉(zhuǎn)向系的功用是改變汽車的行駛方向和保持汽車穩(wěn)定的直線行駛。汽車一般采用前輪轉(zhuǎn)向。轉(zhuǎn)向系的主要組成機(jī)構(gòu)包括:轉(zhuǎn)向盤、轉(zhuǎn)向器、轉(zhuǎn)向傳動(dòng)桿系等。制動(dòng)系是用來(lái)強(qiáng)制汽車減速或停車,并可使汽車在坡道上停放的裝置。為保證汽車在緊急情況下可靠的制動(dòng),應(yīng)有兩套獨(dú)立的制動(dòng)系統(tǒng),其中一種是用機(jī)械方式傳遞其操縱力的。制動(dòng)系的主要組成機(jī)構(gòu)包括:制動(dòng)踏板、駐車制動(dòng)桿、車輪制動(dòng)器等。車身包括駕駛室和各種形式的車廂,用以容納駕駛員、乘客和裝載貨物。1.3電動(dòng)車驅(qū)動(dòng)系統(tǒng)組成一般的汽車結(jié)構(gòu)中,驅(qū)動(dòng)橋包括減速器、差速器、驅(qū)動(dòng)車輪的傳動(dòng)裝置及橋殼等部件。根據(jù)其齒輪類型、主動(dòng)齒輪和從動(dòng)齒輪的安置方法以及減速方式的不同,減速器的結(jié)構(gòu)形式也不同。減速器的傳動(dòng)比、驅(qū)動(dòng)橋的離地間隙和計(jì)算載荷是減速器設(shè)計(jì)的原始數(shù)據(jù),要在總體設(shè)計(jì)時(shí)就確定。由于發(fā)動(dòng)機(jī)在汽車上是縱向安置的,減速器將用來(lái)改變轉(zhuǎn)矩的傳遞方向。為了使汽車有足夠的牽引力和適當(dāng)?shù)淖罡哕囁?,減速器進(jìn)行增大轉(zhuǎn)矩、降低轉(zhuǎn)速的變化。差速器用來(lái)解決左右車輪間的轉(zhuǎn)矩分配問(wèn)題和差速要求。當(dāng)汽車轉(zhuǎn)彎或在不平路面上行駛時(shí),左右車輪在同一時(shí)間內(nèi)所滾動(dòng)的行程是不一樣的,因此其轉(zhuǎn)速也應(yīng)不同。因此,要求驅(qū)動(dòng)橋在傳遞轉(zhuǎn)矩給左右車輪的同時(shí),能使它們以適應(yīng)上述運(yùn)動(dòng)學(xué)要求的不同角速度旋轉(zhuǎn),這一要求是由差速器來(lái)實(shí)現(xiàn)的。裝有差速器的汽車,當(dāng)左右齒輪與地面的附著系數(shù)不同且一個(gè)驅(qū)動(dòng)車輪滑轉(zhuǎn)而失去牽引力時(shí),另一個(gè)附著好的驅(qū)動(dòng)車輪也將喪失牽引功能。驅(qū)動(dòng)車輪的傳動(dòng)裝置的功用在于將轉(zhuǎn)矩由差速器半軸齒輪傳到驅(qū)動(dòng)車輪。對(duì)轉(zhuǎn)向驅(qū)動(dòng)橋,則必須在驅(qū)動(dòng)車輪的傳動(dòng)裝置中安裝等速萬(wàn)向節(jié),對(duì)于非轉(zhuǎn)向驅(qū)動(dòng)橋來(lái)說(shuō),驅(qū)動(dòng)車輪的傳動(dòng)裝置也要用萬(wàn)向節(jié)傳動(dòng)。如果驅(qū)動(dòng)車輪不是轉(zhuǎn)向輪,則車輪直接由連接差速器和輪轂的半軸來(lái)驅(qū)動(dòng),這時(shí)半軸將差速器半軸齒輪與輪轂連接起來(lái)。在裝有輪邊減速器的驅(qū)動(dòng)橋上,輪邊減速器的主動(dòng)齒輪與半軸齒輪以半軸連接。橋殼起著支撐汽車荷重的作用,并將載荷傳遞給車輪,作用在車輪上的牽引力、制動(dòng)力等力都是通過(guò)橋殼傳到車架上。因此,橋殼既有承載作用,又有力的傳遞,同時(shí)還是減速器、差速器、半軸的外殼。在汽車行使過(guò)程中,橋殼承受繁重的載荷。因此,橋殼既要結(jié)構(gòu)簡(jiǎn)單,降低成本以及方便拆裝維修,又要考慮在動(dòng)載荷下有足夠的強(qiáng)度和剛度。輪胎與車輪支撐汽車質(zhì)量,并承受路面的各種反力,如驅(qū)動(dòng)力和制動(dòng)力,在汽車轉(zhuǎn)彎時(shí),還要承受側(cè)向力以及吸收汽車行使時(shí)產(chǎn)生的動(dòng)載荷和振動(dòng)。車輪由輪輞和輪輻組成。輪胎裝在輪輞上,輪輻用輪胎螺栓固定在輪轂上。輪輞是輪胎安裝的基礎(chǔ),既要支撐輪胎,又要保證輪胎拆卸方便。2 電動(dòng)車總體設(shè)計(jì)2.1 技術(shù)參數(shù)1、 額定載人數(shù) 46人2、 總質(zhì)量 約1000 kg3、 最大行駛速度V行 30km/h 4、 最大爬坡度(滿載) 10%5、 最小離地間隙 150mm6、 最小轉(zhuǎn)彎半徑Rmin 4500mm7、 最大制動(dòng)距離 6m8、 自重 576 kg9、 蓄電池電壓 48V10、電控 Acl/48/1802.2 構(gòu)造形式及工作條件1、電動(dòng)車形式:后置后驅(qū) 2、電動(dòng)車動(dòng)力:蓄電池組直流串勵(lì)電動(dòng)機(jī)驅(qū)動(dòng) 額定電壓:48V 3、路面條件:瀝青或混凝土路面2.3主要參數(shù)選擇2.3.1 主要尺寸總長(zhǎng)a=3200mm,總寬w=1600mm,總高h(yuǎn)=1900mm,軸距L=(54%60%)a代入數(shù)據(jù),取整為2000mm, 輪距B=0.75L+100(80) 代入數(shù)據(jù),取整為1350mm, 前懸L=450mm,后懸L=700mm,最小離地間隙150mm2.3.2 電動(dòng)車質(zhì)量座位數(shù):4座,整車質(zhì)量=人均整備質(zhì)量 座位數(shù)=96 5=480kg,參考同類車取 600kg;總質(zhì)量取整為1000 kg。2.3.3 電動(dòng)機(jī)參數(shù):最大功率P=(V+V) (2-1)=(30+30)=1.56kw其中:傳動(dòng)效率0.9,g重力加速度,滾動(dòng)阻力系數(shù)0.0165,C空氣阻力系數(shù)0.65,A汽車正面投影面積,m汽車質(zhì)量。取 安全裕量系數(shù)為1.1,則電機(jī)最大功率應(yīng)為2.18kW,根據(jù)電機(jī)資料,以最接近原則選取2.2kW的串勵(lì)直流電機(jī),其額定轉(zhuǎn)速為,額定轉(zhuǎn)速時(shí)的扭矩為; 2.3.4 輪胎參數(shù)直徑工作半徑,單邊寬最大承載437kg,胎壓0.3MPa;2.3.5 傳動(dòng)比計(jì)算=9.15 (2-2)式中:為汽車的最高車速;是最高車速時(shí)發(fā)動(dòng)機(jī)的轉(zhuǎn)速;為車輪的滾動(dòng)半徑。2.3.6 最大爬坡度計(jì)算= (2-3)=46.6=36.6Km最大牽引力F= (2-4) = =118Kg=0.0165 =11.8%10%,故滿足設(shè)計(jì)要求。2.4 核心件參數(shù)鉛酸蓄電池:DC 48V,160Ah,外形尺寸 522mm 240mm 242mm,重量 260kg;電動(dòng)機(jī): 2.2kW,DC 48V,56A,2800r/min,重量 26kg;轉(zhuǎn)向系 60kg;驅(qū)動(dòng)橋 100kg;車架車廂 80kg。2.5 總體布置計(jì)算2.5.1 各部分質(zhì)量及重心坐標(biāo):蓄電池:尺寸522240242,總電壓48V,容量160AH,重260Kg,重心坐標(biāo)(720,371).直流電動(dòng)機(jī):功率2.2KW,電壓48V,電流57A,轉(zhuǎn)速2800r/min,重26Kg,重心坐標(biāo)(1840,260).轉(zhuǎn)向系統(tǒng):包括前車輪、懸架、制動(dòng)器,重約60Kg,重心坐標(biāo)(100,260).驅(qū)動(dòng)系統(tǒng):包括減速器、差速器、半軸、后車輪、制動(dòng)器,重約100Kg,重心坐標(biāo)(1950,260).車架、車身:重約80Kg,重心坐標(biāo)(1000,225).2.5.2 空載及滿載時(shí)重心坐標(biāo)空載總質(zhì)量約600Kg,滿載總質(zhì)量約880Kg則空載時(shí)重心坐標(biāo) (2-5) 計(jì)算結(jié)果x=1020,y=460滿載時(shí)重心坐標(biāo) 計(jì)算結(jié)果=1080,=5702.5.3 軸荷分配計(jì)算滿載靜止時(shí) (2-6)其中:前軸負(fù)荷,后軸負(fù)荷,汽車總質(zhì)量 L汽車軸距,a質(zhì)心距前軸距離,b質(zhì)心距后軸距離=405Kg,=475Kg滿載行駛時(shí) (2-7)其中為附著系數(shù),在干燥的瀝青或混凝土路面上,該值為0.70.8,取0.75。=275Kg,=605Kg滿載制動(dòng) (2-8)Kg,341Kg2.6 穩(wěn)定性計(jì)算2.6.1 汽車不縱向翻倒的條件,=0.75 (2-9)0.75即滿足條件2.6.2 汽車不橫向翻倒的條件,=0.75 (2-10)0.75即滿足條件2.7 最小轉(zhuǎn)彎直徑的計(jì)算汽車最小轉(zhuǎn)彎直徑=9mD2 (2-11)90002汽車前內(nèi)輪最大轉(zhuǎn)角36.72.8 行程計(jì)算S=Vt (2-17) = V() = 30() =158Km大于目標(biāo)里程120Km,故滿足要求。3 電動(dòng)機(jī)驅(qū)動(dòng)橋設(shè)計(jì)3.1 驅(qū)動(dòng)系統(tǒng)總體設(shè)計(jì)驅(qū)動(dòng)系統(tǒng)的總體設(shè)計(jì)方案示意圖如圖3-1所示,采用單電機(jī)集中驅(qū)動(dòng)系統(tǒng),由減速箱總成、差速器總成及驅(qū)動(dòng)橋組成,驅(qū)動(dòng)電機(jī)與減速器主動(dòng)齒輪直接相連,通過(guò)兩級(jí)減速,將扭矩傳送到左右兩個(gè)驅(qū)動(dòng)輪。電機(jī)軸線與車輪軸線平行,因此減速器采用兩極圓柱齒輪傳動(dòng)。半軸采用全浮式結(jié)構(gòu),與輪轂用螺釘連接傳遞轉(zhuǎn)矩。橋殼采用組合式結(jié)構(gòu),一端由輪轂軸承支承在車輪上,另一端與減速器相連。橋殼的設(shè)計(jì)還要與懸架等配合,根據(jù)它的結(jié)構(gòu)和尺寸設(shè)計(jì)連接部件。圖3-1驅(qū)動(dòng)橋總成3.2 減速器的設(shè)計(jì)3.2.1傳動(dòng)比分配總傳動(dòng)比,故采用兩級(jí)圓柱齒輪減速器。根據(jù)的經(jīng)驗(yàn)公式,取,。3.2.2 運(yùn)動(dòng)和動(dòng)力參數(shù)計(jì)算高速軸: 中間軸: 低速軸 3.2.3 齒輪參數(shù)計(jì)算高速級(jí)齒輪傳動(dòng)設(shè)計(jì):(1)齒輪均采用斜齒傳動(dòng),6級(jí)精度,齒面滲碳淬火。材料選擇:小齒輪:38SiMnMo,調(diào)質(zhì),硬度 320340HBS;大齒輪:35SiMn,調(diào)質(zhì),硬度 280300 HBS。查得,=790,=760; =640,=600。(2)按接觸強(qiáng)度初步確定中心距,并初選主要參數(shù)。 (3-1)式中 小齒輪傳遞的轉(zhuǎn)矩=7.5載荷系數(shù)K:K=1.6。齒寬系數(shù):取=0.4。齒數(shù)比u:暫取u=3.55。許用接觸應(yīng)力: 取最小安全系數(shù)=1.1,按大齒輪計(jì)算=691將以上數(shù)據(jù)代入計(jì)算中心距的公式得=56圓整為標(biāo)準(zhǔn)中心距為=60。按經(jīng)驗(yàn)公式,=(0.0070.02)=(0.0070.02)60=0.421.2 取標(biāo)準(zhǔn)模數(shù)=1。初取,=。 取,精求螺旋角 所以 (3)校核齒面接觸疲勞強(qiáng)度 (3-2)式中分度圓上的圓周力 使用系數(shù)動(dòng)載系數(shù): (3-3) 根據(jù)齒輪圓周速度,齒輪精度等級(jí)為9級(jí)。將有關(guān)值代入式(3-17)得齒向載荷系數(shù): 齒向載荷分配系數(shù):按,查得節(jié)點(diǎn)區(qū)域系數(shù):按,查得。查得接觸強(qiáng)度計(jì)算的重合度及螺旋角系數(shù)查得:首先計(jì)算當(dāng)量齒數(shù)求當(dāng)量齒輪的端面重合度。按,分別查得。所以。按,縱向重合度。按,查得。將以上各數(shù)值代入齒面接觸應(yīng)力計(jì)算公式得計(jì)算安全系數(shù): (3-4)式中,壽命系數(shù):先計(jì)算應(yīng)力循環(huán)次數(shù):對(duì)調(diào)質(zhì)鋼,查得。潤(rùn)滑油模影響系數(shù):按照,選用220號(hào)中級(jí)壓型工業(yè)齒輪油,其運(yùn)動(dòng)粘度,查得。工作硬化系數(shù):因?yàn)樾↓X輪齒面未硬化處理,齒面未光整,故取。接觸強(qiáng)度計(jì)算的尺寸系數(shù)。將以上數(shù)值代入安全系數(shù)的計(jì)算公式得查得,。,故安全。(4)校核齒根彎曲疲勞強(qiáng)度 (3-5)式中彎曲強(qiáng)度計(jì)算的載荷分布系數(shù):彎曲強(qiáng)度計(jì)算的載荷分配系數(shù):復(fù)合齒行系數(shù):按,查得。彎曲強(qiáng)度計(jì)算的重合度與螺旋角系數(shù):按,查得將以上各數(shù)值代入齒根彎曲應(yīng)力計(jì)算公式得計(jì)算安全系數(shù): (3-6)式中,壽命系數(shù):對(duì)調(diào)質(zhì)鋼,按,查得,按,查得相對(duì)齒根圓角敏感系數(shù)。相對(duì)齒根表面狀況系數(shù):齒面粗糙度,得。尺寸系數(shù):查得。將以上數(shù)值代入安全系數(shù)的公式得查得,取。及均大于,故安全。(5)主要幾何尺寸取低速級(jí)齒輪傳動(dòng)設(shè)計(jì)(1)齒輪均采用斜齒傳動(dòng),6級(jí)精度,齒面滲碳淬火。材料選擇:小齒輪:38SiMnMo,調(diào)質(zhì),硬度 320340HBS;大齒輪:35SiMn,調(diào)質(zhì),硬度 280300 HBS。查得,=790,=760; =640,=600。(2)按接觸強(qiáng)度初步確定中心距,并初選主要參數(shù)。 (3-1)式中 小齒輪傳遞的轉(zhuǎn)矩=26.625載荷系數(shù)K:K=1.6。齒寬系數(shù):取=0.54。齒數(shù)比u:暫取u=2.54。許用接觸應(yīng)力: 取最小安全系數(shù)=1.1,按大齒輪計(jì)算=691將以上數(shù)據(jù)代入計(jì)算中心距的公式得=74.9圓整為標(biāo)準(zhǔn)中心距為=100。按經(jīng)驗(yàn)公式,=(0.0070.02)=(0.0070.02)100=0.72 取標(biāo)準(zhǔn)模數(shù)=1.5。初取,=。 取,精求螺旋角 所以 (3)校核齒面接觸疲勞強(qiáng)度 (3-2)式中分度圓上的圓周力 使用系數(shù)動(dòng)載系數(shù): (3-3) 根據(jù)齒輪圓周速度,齒輪精度等級(jí)為9級(jí)。將有關(guān)值代入式(3-17)得齒向載荷系數(shù): 齒向載荷分配系數(shù):按,查得節(jié)點(diǎn)區(qū)域系數(shù):按,查得。查得接觸強(qiáng)度計(jì)算的重合度及螺旋角系數(shù)查得:首先計(jì)算當(dāng)量齒數(shù)當(dāng)量齒輪的端面重合度。按,分別查得。所以。按,縱向重合度。按,查得。將以上各數(shù)值代入齒面接觸應(yīng)力計(jì)算公式得計(jì)算安全系數(shù): (3-4)式中,壽命系數(shù):先計(jì)算應(yīng)力循環(huán)次數(shù):對(duì)調(diào)質(zhì)鋼,查得。潤(rùn)滑油模影響系數(shù):按照,選用220號(hào)中級(jí)壓型工業(yè)齒輪油,其運(yùn)動(dòng)粘度,查得。工作硬化系數(shù):因?yàn)樾↓X輪齒面未硬化處理,齒面未光整,故取。接觸強(qiáng)度計(jì)算的尺寸系數(shù)。將以上數(shù)值代入安全系數(shù)的計(jì)算公式得查得,。,故安全。(4)校核齒根彎曲疲勞強(qiáng)度 (3-5)式中彎曲強(qiáng)度計(jì)算的載荷分布系數(shù):彎曲強(qiáng)度計(jì)算的載荷分配系數(shù):復(fù)合齒行系數(shù):按,查得。彎曲強(qiáng)度計(jì)算的重合度與螺旋角系數(shù):按,查得將以上各數(shù)值代入齒根彎曲應(yīng)力計(jì)算公式得計(jì)算安全系數(shù): (3-6)式中,壽命系數(shù):對(duì)調(diào)質(zhì)鋼,按,查得,按,查得相對(duì)齒根圓角敏感系數(shù)。相對(duì)齒根表面狀況系數(shù):齒面粗糙度,得。尺寸系數(shù):查得。將以上數(shù)值代入安全系數(shù)的公式得查得,取。及均大于,故安全。(5)主要幾何尺寸取3.2.4 軸的設(shè)計(jì)材料選擇45鋼,調(diào)質(zhì)處理,硬度217255HBS,許用疲勞應(yīng)力。(1)高速軸a 最小軸徑的確定取A=115由于有花鍵,適當(dāng)增加軸徑,取。b 主要分布零件有:齒輪、軸承、軸承端蓋等。c 根據(jù)工況,選擇軸承類型為滾動(dòng)軸承 6002。 基本尺寸:15mm32mm9mm 配合軸段直徑為15mmd 齒輪安裝:安裝軸段直徑24mm,軸段長(zhǎng)度26mm。e 齒輪定位:由于齒輪分度圓直徑小于兩倍軸徑,故齒輪采用齒輪軸。(2)中間軸a 中間軸為實(shí)心軸,故 取A=115由于開(kāi)有鍵槽,軸徑適當(dāng)增加,取。b主要分布零件有:齒輪、軸承、鍵、軸承端蓋等。c 根據(jù)工況,選擇軸承類型為滾動(dòng)軸承 6004。 基本尺寸:20mm42mm12mm 配合軸段直徑20mmd 齒輪安裝:安裝軸段直徑 大齒輪25mm,小齒輪25mm。 安裝軸段長(zhǎng)度 大齒輪32mm,小齒輪40mm。e 齒輪定位:大齒輪:一端采用軸肩定位,軸段直徑32mm,軸段長(zhǎng)度8mm。 另一端采用套筒定位,套筒內(nèi)徑20mm,外徑28mm,長(zhǎng)度10mm。 徑向定位采用平鍵,基本尺寸33mm10mm8mm。小齒輪:一端采用軸肩定位,軸段直徑25mm,軸段長(zhǎng)度42mm。 另一端采用套筒定位,套筒內(nèi)徑20mm,外徑32mm,長(zhǎng)度4mm。 徑向定位采用平鍵,基本尺寸26mm8mm7mm。3.2.5 平鍵的強(qiáng)度校核中間軸:?jiǎn)蝹€(gè)平鍵,基本尺寸26mm8mm7mm鍵連接的許用擠壓應(yīng)力,故滿足要求。3.2.6 軸的強(qiáng)度校核(1)高速軸高速軸的受力分析如圖3-1所示。高速軸傳遞的轉(zhuǎn)矩 齒輪的圓周力 齒輪的徑向力 齒輪的軸向力 計(jì)算作用在軸上的支反力:如圖3-1(a),垂直面內(nèi)的支反力:如圖3-1(c),水平面內(nèi)的支反力 :計(jì)算齒輪中心C處的彎矩 :畫出高速軸在垂直面和水平面內(nèi)的彎矩圖,如圖3-1(b)、(d)所示。計(jì)算C處的合成彎矩: 畫出合成彎矩圖如圖3-1(e)所示。畫出扭矩圖如圖3-1(f)所示。Fv1Fv2T0Ft1abcdefFh1Fh2Fr1Fa1ABC22269Nmm5538Nmm4487.5Nmm22947Nmm22716Nmm7500Nmm圖3-2 高速軸受力分析圖校核軸的強(qiáng)度:由彎矩圖和扭矩圖可以看出,承受最大彎矩和扭矩的截面C處是危險(xiǎn)截面,對(duì)其進(jìn)行校核。按轉(zhuǎn)矩為脈動(dòng)變化取修正系數(shù),由于截面C處為實(shí)心軸,故。則 故軸的強(qiáng)度滿足要求。(2)中間軸中間軸的受力分析如圖3-2所示。中間軸傳遞的轉(zhuǎn)矩:齒輪的圓周力:齒輪的徑向力:齒輪的軸向力:計(jì)算作用在軸上的支反力:如圖3-2(a),垂直面內(nèi)的支反力:如圖3-2(c),水平面內(nèi)的支反力:計(jì)算齒輪中心的彎矩:畫出中間軸垂直面和水平面內(nèi)的彎矩圖,如圖3-2(b)、(d)所示。計(jì)算C處和D處的合成彎矩:畫出合成彎矩圖,如圖3-2(e)所示。畫出扭矩圖,如圖3-2(f)所示。Fv1Fv2Ft2Ft3aFh1Fh2Fr2Fa2Fa3Fr3bcdefACDB15318.6Nmm27791.6Nmm-3294.6Nmm844.8Nmm-495.7Nmm-4895.6Nmm15341.9Nmm16081.9Nmm27796.9Nmm27986.9Nmm26625Nmm圖3-3 中間軸受力分析圖校核軸的強(qiáng)度:由彎矩圖和扭矩圖可以看出,承受最大彎矩和扭矩的截面D處,即齒輪3的中心處是危險(xiǎn)截面,對(duì)其進(jìn)行校核。按轉(zhuǎn)矩為脈動(dòng)變化取修正系數(shù),由于截面C處為實(shí)心軸,故。則 故軸的強(qiáng)度滿足要求。3.2.7 軸承的壽命校核設(shè)計(jì)標(biāo)準(zhǔn) (1)高速軸軸承軸承代號(hào):6002查閱機(jī)械設(shè)計(jì)手冊(cè),得:Cr=5580N, Co=2850N。根據(jù)工況,載荷平穩(wěn),取。由機(jī)械設(shè)計(jì)表17.5知,。FraFrbFa1FsaFsb圖3-4 高速軸軸承受負(fù)荷示意圖計(jì)算軸承徑向載荷: 計(jì)算附加軸向力: 計(jì)算軸承所受軸向載荷:因?yàn)?所以左端軸承a被壓緊,右端軸承b被放松。由此可得: 計(jì)算當(dāng)量動(dòng)載荷: 由機(jī)械設(shè)計(jì)表17.7查得e=0.28。由于,查機(jī)械設(shè)計(jì)表17.7得X=0.56,Y=1.55。當(dāng)量動(dòng)載荷 計(jì)算軸承壽命: 故滿足要求。(2)中間軸軸承軸承代號(hào):6004查閱機(jī)械設(shè)計(jì)手冊(cè),得:Cr=9380N, Co=5020N。根據(jù)工況,載荷平穩(wěn),取。由機(jī)械設(shè)計(jì)表17.5知,。FraFrbFa2FsaFsbFa3圖3-5 中間軸軸承受負(fù)荷示意圖計(jì)算軸承徑向載荷: 計(jì)算附加軸向力: 計(jì)算軸承所受軸向載荷:因?yàn)?所以右端軸承b被壓緊,左端軸承a被放松。由此可得: 計(jì)算當(dāng)量動(dòng)載荷: 查機(jī)械設(shè)計(jì)表17.7并用線性插值法得e=0.27。由于查機(jī)械設(shè)計(jì)表17.7并用線性插值法求得X=0.56,Y=1.64。當(dāng)量動(dòng)載荷 計(jì)算軸承壽命: 故滿足要求。3.2.8 減速器箱體的設(shè)計(jì)減速器箱體是減速器中結(jié)構(gòu)和形狀最復(fù)雜的部件,大都采用鑄造生產(chǎn)。在箱體的設(shè)計(jì)過(guò)程中,不僅要保證一定的支承剛度,要便于軸系的安裝外,還要盡量使工藝性好,制造簡(jiǎn)單,外形美觀。在本課題設(shè)計(jì)的驅(qū)動(dòng)系統(tǒng)中,減速器具有一定的特殊性。與普通的電機(jī)和減速器連接不同,除了電機(jī)的輸出軸要與減速器的高速軸用花鍵連接外,電機(jī)的外殼要與減速器的箱體用螺釘連接起來(lái),這使得減速器箱體的設(shè)計(jì)比較復(fù)雜,也成為了設(shè)計(jì)中的一個(gè)關(guān)鍵。為了解決這一關(guān)鍵問(wèn)題,采用了側(cè)面箱蓋的方式,在減速器箱體的另一側(cè)給安裝電機(jī)的法蘭留出空間。總體的結(jié)構(gòu)確定后,開(kāi)始細(xì)化設(shè)計(jì)。首先根據(jù)兩極傳動(dòng)的中心距和傳動(dòng)齒輪的大小確定箱體內(nèi)部空間尺寸及軸承孔的位置和大小。然后根據(jù)剛度的要求,使得壁厚不小于8mm,并且設(shè)計(jì)外形結(jié)構(gòu)。在軸承座處要加大壁厚,且將外壁設(shè)計(jì)成凸臺(tái),可以減小加工面。安裝電機(jī)的法蘭上的螺釘孔的布置設(shè)計(jì)是一個(gè)關(guān)鍵問(wèn)題,它們不僅不能與中間軸的軸承孔干涉,而且還要給螺釘?shù)陌惭b提供空間。為此,法蘭設(shè)計(jì)成正方行結(jié)構(gòu),四個(gè)螺釘安裝在四個(gè)角上。為了保證軸承和軸的安裝精度,在箱體和箱蓋上設(shè)計(jì)了定位銷,在加工軸承孔時(shí)用定位銷將箱體和箱蓋連成一體加工。同時(shí),由于采用了側(cè)面箱蓋的形式,為了防止?jié)櫥托孤?,箱體和箱蓋連接處采用液態(tài)密封膠密封。3.3 半軸的設(shè)計(jì)3.3.1 半軸的形式半軸的形式有全浮式、半浮式和3/4浮式三種。此處采用全浮式半軸結(jié)構(gòu),驅(qū)動(dòng)車輪通過(guò)兩個(gè)軸承支承在驅(qū)動(dòng)橋殼上,半軸插在橋殼里面,內(nèi)端用花鍵與減速器低速軸連接,外端通過(guò)法蘭盤用螺釘與輪轂相連,轉(zhuǎn)矩由半軸傳遞到驅(qū)動(dòng)車輪上。這種支承方式,路面對(duì)車輛的各種反力及由這些反力引起的彎矩都由橋殼承受,半軸只承受轉(zhuǎn)矩,不承受彎矩和軸向力。3.3.2 半軸軸徑的確定由于采用全浮式半軸結(jié)構(gòu),半軸只承受轉(zhuǎn)矩,故按照扭轉(zhuǎn)強(qiáng)度來(lái)設(shè)計(jì)。全浮式半軸其計(jì)算載荷可按最大附著力矩計(jì)算: (3-7)式中:為負(fù)荷轉(zhuǎn)移系數(shù),查表得;為驅(qū)動(dòng)橋的最大軸載質(zhì)量,;為車輪滾動(dòng)半徑,;為附著系數(shù),取。代入計(jì)算得:全浮式半軸的扭轉(zhuǎn)應(yīng)力按下式計(jì)算;式中:許用剪應(yīng)力計(jì)算得:由于加工花鍵,軸徑適當(dāng)增加,取。3.3.3 花鍵的設(shè)計(jì)和校核花鍵采用矩形花鍵,齒數(shù)Z=6,其基本尺寸為26mm23mm6mm,長(zhǎng)度L=30mm。此處花鍵連接為靜連接,主要失效形式為齒面壓潰。強(qiáng)度校核:式中,T為工作轉(zhuǎn)矩,Nmm; 為各齒間載荷分配不均勻系數(shù),取; Z為花鍵齒數(shù); h=(D-d)/2,D和d分別為花鍵軸的外徑和內(nèi)徑,mm; 為齒的工作長(zhǎng)度,mm; 為花鍵平均直徑,mm; 為許用擠壓應(yīng)力,MPa。3.3.4 半軸連接螺釘強(qiáng)度校核由于半軸只承受轉(zhuǎn)矩作用,因此半軸與輪轂的連接螺釘只受剪切力作用,可能損壞的形式有螺釘被剪斷、螺釘或孔壁被壓潰。螺釘性能等級(jí)4.8則:屈服強(qiáng)度 s=320MPa許用切應(yīng)力 =s/2.5=320/2.5=128MPa許用擠呀壓應(yīng)力p= s/1.25=320/1.25=256MPa(1)螺釘抗剪強(qiáng)度校核單個(gè)螺釘所受的剪力:式中,T為螺釘所受扭矩,Nm; n為螺釘數(shù)目; r為螺釘中心與半軸軸線的垂直距離,m。則螺釘?shù)目辜魪?qiáng)度 ,故滿足要求。式中,F(xiàn)s為單個(gè)螺釘所受剪力,N;d為螺釘抗剪面直徑,mm; m為螺釘抗剪面數(shù)目。(2)螺釘與孔壁的擠壓強(qiáng)度校核擠壓強(qiáng)度 ,故滿足要求。式中,F(xiàn)s為單個(gè)螺釘所受剪力,N;d為螺釘抗剪面直徑,mm; h為螺釘與孔壁擠壓面最小高度,mm。結(jié)論:綜合以上兩項(xiàng)強(qiáng)度校核可知,半軸與輪轂連接的螺釘強(qiáng)度滿足要求。3.4 輪轂的設(shè)計(jì)3.4.1 輪轂的外形設(shè)計(jì)輪轂是連接半軸和車輪的部件,是傳遞轉(zhuǎn)矩部件的一個(gè)組成部分。輪轂的材料選擇HT250,其內(nèi)部主要有兩個(gè)與軸承外圈配合的孔,用來(lái)支承橋殼。外部主要是與輪輞的一個(gè)孔軸配合,為了起到定位作用,使車輪在運(yùn)行過(guò)程中不產(chǎn)生偏移,此孔軸配合采用過(guò)盈配合。3.4.2 輪轂與輪輞的連接螺栓強(qiáng)度校核按螺栓受剪切力進(jìn)行校核。螺栓性能等級(jí)4.8則:屈服強(qiáng)度 s=320MPa許用切應(yīng)力 =s/2.5=320/2.5=128MPa許用擠壓應(yīng)力p= s/1.25=320/1.25=256MPa(1)螺栓抗剪強(qiáng)度校核單個(gè)螺栓所受的剪力 式中,T為螺栓所受扭矩,Nm; n為螺栓數(shù)目; r為螺栓中心與半軸軸線的垂直距離,m。則螺栓的抗剪強(qiáng)度 ,故滿足要求。式中,F(xiàn)s為單個(gè)螺栓所受剪力,N;d為螺栓抗剪面直徑,mm; m為螺栓抗剪面數(shù)目。(2)螺栓與孔壁的擠壓強(qiáng)度校核擠壓強(qiáng)度 ,故滿足要求。式中,F(xiàn)s為單個(gè)螺栓所受剪力,N;d為螺栓抗剪面直徑,mm; h為螺栓與孔壁擠壓面最小高度,mm。結(jié)論:綜合以上兩項(xiàng)強(qiáng)度校核可知,輪轂與輪輞連接的螺栓強(qiáng)度滿足要求。3.5 驅(qū)動(dòng)橋殼的設(shè)計(jì)3.5.1 驅(qū)動(dòng)橋殼的結(jié)構(gòu)設(shè)計(jì)驅(qū)動(dòng)橋殼一般有可分式、整體式和組合式三種結(jié)構(gòu)形式。此處采用組合式結(jié)構(gòu),使得拆裝和維修更加方便。橋殼的一端通過(guò)一對(duì)軸承支承在輪轂上,另一端用螺釘與減速器箱體連接。由于驅(qū)動(dòng)橋殼還需要與車架連接,根據(jù)后懸架的結(jié)構(gòu)和尺寸,在橋殼的外端設(shè)計(jì)凹槽和它連接。在裝有軸承的一端車有螺紋,用于圓螺母固定軸承內(nèi)圈。3.5.2 驅(qū)動(dòng)橋殼的強(qiáng)度計(jì)算(1)橋殼的靜彎曲應(yīng)力計(jì)算橋殼可看成一根空心橫梁,兩端經(jīng)輪轂軸承支承于車輪上,在橋殼與車架的鉸接處承受車身載荷。其受力簡(jiǎn)圖如圖3-5所示。F1F2N1N2BS圖3-6 驅(qū)動(dòng)橋殼受力簡(jiǎn)圖由圖中可以看出,橋殼與車架鉸接處為危險(xiǎn)截面,對(duì)其進(jìn)行強(qiáng)度校核。該處所受彎矩:式中,F(xiàn)1為地面作用于車輪上的反力,N; G為電動(dòng)車滿載時(shí)的重量,N; gw為車輪、輪轂、制動(dòng)器的重量,N;B為前輪中心距,m;S為橋殼和車架鉸接中心的距離,m。則:彎曲應(yīng)力 故強(qiáng)度滿足要求。(2)電動(dòng)車以最大牽引力行駛時(shí)的橋殼強(qiáng)度計(jì)算取汽車加速時(shí)的質(zhì)量轉(zhuǎn)移系數(shù)m2=1.2,則橋殼與車架鉸接處所受的垂向彎矩為:在行駛時(shí),驅(qū)動(dòng)車輪所受的最大切向反力:式中,T2為驅(qū)動(dòng)輪得到的轉(zhuǎn)矩,Nm; r為前輪的滾動(dòng)半徑,m。則橋殼與車架鉸接處所受的水平彎矩為:橋殼還承受驅(qū)動(dòng)橋傳遞轉(zhuǎn)矩而產(chǎn)生的反作用力矩:則橋殼與車架鉸接處所受的合成彎矩為:則彎曲應(yīng)力: 故強(qiáng)度滿足要求。(3)電動(dòng)車緊急制動(dòng)時(shí)橋殼強(qiáng)度計(jì)算取汽車緊急制動(dòng)時(shí)的質(zhì)量轉(zhuǎn)移系數(shù)m=1.2,則橋殼與車架鉸接處所受的垂向彎矩為:橋殼與車架鉸接處所受的水平彎矩為:緊急制動(dòng)時(shí)鉸接點(diǎn)外側(cè)還承受制動(dòng)力所引起的轉(zhuǎn)矩則橋殼與車架鉸接處所受的合成彎矩為:則彎曲應(yīng)力: 故強(qiáng)度滿足要求。(4)電動(dòng)車受最大側(cè)向力時(shí)的橋殼強(qiáng)度計(jì)算假設(shè)電動(dòng)車向左緊急轉(zhuǎn)彎,則左輪承受的最大垂向力為車重.即則鉸接處所受彎矩為:彎曲應(yīng)力: 故強(qiáng)度滿足要求。3.5.3 橋殼與減速器連接螺釘強(qiáng)度校核螺釘M8,性能等級(jí)8.8級(jí)。取安全系數(shù)S=1.2,則按緊急制動(dòng)時(shí)的彎矩對(duì)螺釘進(jìn)行強(qiáng)度校核。則單個(gè)螺釘承受的最大工作載荷為:式中,n為螺釘個(gè)數(shù); r為螺釘中心直半軸軸線的垂直距離,m。彎曲應(yīng)力為:故螺釘強(qiáng)度滿足要求。3.6 輪轂軸承的壽命計(jì)算設(shè)計(jì)標(biāo)準(zhǔn)。左端軸承基本代號(hào)32009,右端軸承基本代號(hào)32010。當(dāng)電動(dòng)車直線行使時(shí),沒(méi)有外界軸向載荷,其受力示意圖如圖3-6所示。Fr1Fr2Fs1Fs2NABC圖3-7 輪轂軸承受負(fù)荷示意圖車身重G按1140kg計(jì)算,則N=G/2=1140/4=285kg。查機(jī)械設(shè)計(jì)手冊(cè)得,X=0.40,Y=1.5,Cr1=67800N,Cr2=73200N。由于,且,Y1=Y2所以由于該處軸承有較大沖擊,取沖擊載荷系數(shù)fp=1.2。計(jì)算當(dāng)量動(dòng)載荷計(jì)算軸承壽命:故這對(duì)軸承設(shè)計(jì)符合要求。致 謝經(jīng)過(guò)四個(gè)月的辛勤勞動(dòng),我終于順利地完成了畢業(yè)設(shè)計(jì)。在畢業(yè)設(shè)計(jì)的過(guò)程當(dāng)中,老師們和周圍的同學(xué)給了我極大的幫助,在此對(duì)他們表示感謝!在整個(gè)畢業(yè)設(shè)計(jì)過(guò)程當(dāng)中,指導(dǎo)老師給了我多方面的幫助。他不僅給我提出了很多寶貴的意見(jiàn)和建議,還給我提供了很多相關(guān)的技術(shù)支持,幫助我解決了一個(gè)又一個(gè)的難題。王老師對(duì)待我的每一張圖紙都仔細(xì)審閱,在指出每一個(gè)微小錯(cuò)誤的同時(shí)也結(jié)合自己豐富的機(jī)械設(shè)計(jì)經(jīng)驗(yàn),給我講解一些常用的設(shè)計(jì)方法和注意事項(xiàng),使我受益非淺。參考文獻(xiàn):1 陸植.電動(dòng)車設(shè)計(jì).北京:機(jī)械工業(yè)出版社,19912 陳慕忱.裝卸搬運(yùn)車輛.北京:人民交通出版社,19863 吳克堅(jiān),于曉紅,錢瑞明.機(jī)械設(shè)計(jì).北京:高等教育出版社,20034 成大先等.機(jī)械設(shè)計(jì)手冊(cè)(第四版),第一卷. 北京:化學(xué)工業(yè)出版社,1993.15 機(jī)械工程手冊(cè) 第13卷 物料搬運(yùn)設(shè)備卷/機(jī)械工程手冊(cè),電機(jī)工程手冊(cè)編輯委員會(huì)(編) 北京:機(jī)械工業(yè)出版社,19976 朱禮順,梅家強(qiáng),陳福來(lái).電動(dòng)車驅(qū)動(dòng)橋制動(dòng)系統(tǒng)漏油故障分析與工藝改進(jìn).工程機(jī)械,2006(7),60617 劉惟信.驅(qū)動(dòng)橋. 北京:人民交通出版社,19878 陶新良.電動(dòng)車和電動(dòng)牽引車的構(gòu)造與維修. 北京:中國(guó)物資出版社,20069 趙九江,趙祖耀.材料力學(xué). 哈爾濱:哈爾濱工業(yè)大學(xué)出版社,198710楊曉軍.交流驅(qū)動(dòng)系統(tǒng)引領(lǐng)電動(dòng)車技術(shù)革命.電動(dòng)車技術(shù),2006(1)11張啟君,宋玉萍,馬瑞永,常仁齊,張宏,仇國(guó)劍.國(guó)內(nèi)外電動(dòng)車行業(yè)現(xiàn)狀及發(fā)展戰(zhàn)略探討.建筑機(jī)械化,2003(9)12張忠澤.電動(dòng)車傳動(dòng)系統(tǒng)設(shè)計(jì).機(jī)電工程,1998(5)13陸剛.電動(dòng)車的技術(shù)發(fā)展趨勢(shì).物流技術(shù)與應(yīng)用,2007(7)14蔣宏元.電動(dòng)車的優(yōu)勢(shì).現(xiàn)代制造,2007(25)15錢可強(qiáng).機(jī)械制圖 .北京:高等教育出版社,200716王之棟,王大康.機(jī)械設(shè)計(jì)綜合課程設(shè)計(jì).北京:機(jī)械工業(yè)出版社,200317外文資料譯文Driving Axlel automobile driving axleThe driving axle is one of cross bars supporting a vehicle, on which the driving wheels turn .The driving axle includes a housing ,an axle drive ,a differential , tow axle shafts (half axles ),and final drives (if any ) .The axle .or main, drive is a drive-line unit that increases the torque delivered by the transmission and transmits it to the driving wheels, via the differential. In automobiles, the axle drive shaft, usually called the propeller shaft.The axle drive may be a Single or a double-stage type, the former comprising a pair of gears and the latter .tow pairs of gear. Drive pinion I may be made integral with its shaft, or it may be detachable from the shaft. Driving gears and are usually made in the form of detachable gear rings that are bolted or riveted to the differential case .Alex drive bevel pinions and gears are made with helical teeth in order to reduce noise in operation.The tow-stage axle drive consists of a pair of bevel gears and a pair of spur gears. Drive bevel pinion drives bevel gear that is fixed to the flange of the intermediate shaft made integral with 2nd stage driving spur gear .Gears meshes with driven spur gear which is fastened to the case rotates in taper roller bearings installed in the differential carrier that makes part of the driving axle housing.The differential is a drive-line unit that divides the torque applied to it between the tow axle shafts and allows one driving wheel to turn at a different speed from the other.The differential consists of case, cross or spider pinion .and side gears, also known as axle gears .the differential pinions are freely mounted on the cylindrical arms of the spider, which is held in the differential case, and remain in constant mesh with the differential side gears.When the automobile is moving down a straight and even road, both driving wheels meet with one and the same rolling resistance. In this case, axle driven gear, or differential ring gear, causes the differential case to rotate .when the differential case rotates pinions and their spider arms move around in a circle with tow differential side gears are meshed with the pinions, the side gears must rotate, causing the axle shafts and their associated driving wheels to turn. With equal resistance applied to each wheel, the differential pinions do not rotate. They apply equal torque to the side gears and therefore both driving wheels rotate at one and the same speed is unequal ,the differential pinions rotate on their spider arms as well as drive round with the differential case .supposing that one of the axle shaft is prevented from rotating ,the differential pinions would have to walk around the stationary side gear ,causing the other side gear to rotate at twice its normal speed .You can now see how the differential can allow one driving wheel to turn faster than the other .Whenever the automobile goes around a turn ,the outer driving wheel travels a greater distance than the inner drive wheel .the inner wheel speeds up proportionately ,thanks to the differential pinions that rotate on their spider arms and ,rolling around the slower side gear send more rotary motion to the outside wheel. The differential side gears are splined on to the inner ends of the axle shafts .The other ends of the shafts are attached to the driving wheel hubs by means of flanges .Trucks use full floating axle shafts .Such axle shafts are acted upon by torque only .All the other loads acting on the driving wheels are taken by the driving axle housing, because the wheel hubs are supported by bearings mounted on the housing.l Driving axle of general-purpose wheeled tractorGeneral-purpose wheeled tractors are a four-wheel drive type, they have tow driving axles-front and rear .Both axles are similar in construction, expect for the housing. Each driving axle consist if a housing, an axle drive ,a differential ,and final drives .The front and rear-axles drives are interchangeable and comprise a pair of spiral bevel gears . The axle drive pinion is made integral with a shaft that is supported by tow taper roller bearings installed in axle drive pinion carrier .The latter is accommodated in differential carrier and is fixed to it by bolts. The flange of the axle drive pinion carrier is provided with threaded holes to fit puller screws that are used to remove the axle drive pinion carrier from the differential carrier .The position of the drive pinion relative to the centerline of the axle is adjust by means of a pack of shims placed under the flange of the drive pinion carrier Shims palace under the cone of the front bearing are used to adjust the preload on the drive pinion bearings. Splined to adjust the preload on the drive pinion shaft is universal-joint flange .The axle drive gear is bolted to the differential case flange.THE DIFFERENTIAL consists of case, four pinions, and tow side gears .The differential case comprise tow halves that are bolted together and supported by taper roller bearings installed in the differential carrier .Screwed in the bearings housing from the outside are nuts used to adjust the backlash between the ring gear and drive pinion teeth and the side bearing preload.Welded to the top of the driving axle housing at both its ends are spring pads .The housing of both its ends are spring axels are provided with filler ,overflow ,and drain holes closed by plugs .Both housing also have vents ,The rotating components of the driving axles are lubricated with transmission oil .As distinct from the automobiles considered in this text, all tractors include final drives in their power trains .The final drives of general-purpose wheel tractors are referred to as wheel-hub reduction gears.While transmitting power to the driving wheels, wheel-hub reduction can increase their torque .These are planetary reduction gear sets consist of sun gear ,or wheel ,three planet ,or pinion ,gears ,planet or pinion ,carrier .stationary internal ,or ring ,gear ,and housing.The sun gear is splined to the outer end of the axle shaft is splined to the differential side gear .The cylindrical planet gears are in constant mesh with both the sun gear and the ring gear and are free to rotate on roller bearings mounted on shafts that are attached to the planet carrier .The planet carrier is fasted to the reduction gear housing by means of studs and nuts .The flange of housing ,driving wheel brake drum 13,and wheel hub are clamped together by bolts .The planet carrier and reduction gear housing form the driven part of the planetary gear set and rotate with the driving wheel of the tractor .The driving gear hub is supported by taper roller bearings mounted on axle shaft housing ,or axle sleeve .The axle sleeve is connected to the stationary ring gear by means of adapter hub that has internal splines and external teeth . The splines are meshed with matching splines on the axle sleeve, and the teeth are meshed with internal teeth ring gear.Wheels and its maintainModern wheeled tractors and automobiles use pneumatic-tired disc wheels. As a result of the driving wheel tires gripping the road, the rotary motion of the wheels is transformed into the translational motion of the tractor or automobile.According to their purpose, wheels are classified as driving .driven steerable, and combination types.Trucks and general-purpose wheeled tractors have all their wheels of one and the same size .Row-crop tractors have their rear wheels larger than the front wheels .The rear wheels carry the major proportion of the load due to the weight of the tractor .The front wheels are loaded lighter and this makes them easier to turn and provide good directional steering stability, which is essential for row-crop work.A TRUCK WHEEL consists of disc and flat base rim that is made integral with it, while the other flange is formed by detachable side ring that is held to the rim by split lock ring on the rim .which doubles as a side ring and a lock ring.The wheel disc is provided with holes for mounting the wheel on the wheel mounting bolts ,or wheel studs ,on the wheel hub ,where it is fixed by nuts .Both the holes and the nuts are tapered to ensure exact location of the wheel on its hub .The rear driving axles of trucks carry tow wheels at each end .The inner wheels are held to the hubs by cap nuts that are threaded both on the inside and on the outside .and the outer wheels are mounted on the cap nuts and fixed in place by taper nuts screwed on the nuts .The wheel nuts on the right side of truck have right-hand threads, whereas the nuts on the left side of the truck are threaded left-hand .The reason is to tighten the nuts, not loosen them, and thus prevent them from working loose on acceleration and braking.An automobile pneumatic tire consists of casing, inner tube, and flap .The tire casing comprises tread, side walls, and beads .Tires for good roads use small tread patterns, while those for bad roads or cross country service large tread patterns.The inner tube is made in the form of a hollow elastic rubber doughnut that is inflated with air after it is installed inside the tire and the tire is put on the wheel rim .The inner tube is inflated through tire valve that consists of housing 11,valve inside ,and cap .The valve housing is made of brass in the dorm of a flanged tube that is mounted in the inner tube by means of a washer and a nut and sticks out through a hole in the wheel .Some tire valve housing are of comprise construction :the upper part is made of brass and the lower part ,of rubber that is vulcanized on to the inner tube .The valve inside is a check valve that opens to let air in the inner tube when an air closed ,spring pressure and air pressure inside the tube hold the valve .When the valve is closed ,spring pressure and air pressure inside the tube hold the valve in its seat .It includes core with a rubber ring ,a plunger pin ,and a spring .The valve inside is Screwed in the tire valve housing and is closed by the cap Screwed on the housing.To the construction of the driving and steerable wheels, each wheel comprises hub , disc with rim ,and tire with inner tube .The rim is welded to the disc and the disc is bolted to the hub .The driving wheel tires are of low-pressure type and have heavy tread bars for better traction. The driving wheel hub is keyed to axle shaft and is fixed in place by means of bolted-on insert with worm whose threads mesh with the rack teeth cut in the half axle .By turning the worm one can change the position of the wheel on the axle shaft to obtain the desired track width .Before doing this ,it is necessary to jack up the rear part of the tractor to clear the wheels of the ground and loosen the bolts that hold the inserts to the wheels hubs .Should this adjustment prove insufficient ,the track width can further be increased by placing the wheels with the concaves of their discs facing inwards.On some row-crop tractors ,the rear wheel discs are bolts to lugs welded on the wheel rims .In this case ,the crack width can be changed by bolts the discs in alternative positions to the lugs .Also the concave wheel discs may be used either with the concave facing inwards or outwards.Trouble-free operation of automobiles and wheeled tractors largely depends on the condition of the tires. Therefore, during operation, one should adhere to following rules.Prevent fuel and, or oil from getting onto the tires. Cleans the tires regularly from dirt and remove all foreign articles, such as stones, form the treads. Do not apply brakes sharply, never start away form rest with a jerk, and avoid making sharp turns, for all this causes uneven wear of the tires. Do not allow excessive slipping of the driving wheels. When preparing your tractor or automobile for a long-term storage, jack up the wheels and put trestles under the axles or frame to relieve the tires.The service life of tires is expressed in terms of their mileage. For most bias (ordinary) truck tires, the guaranteed mileage amounts to 50000 km. Observing the above rules will help prolong the useful service life of tires.驅(qū)動(dòng)橋汽車的驅(qū)動(dòng)橋驅(qū)動(dòng)橋是一個(gè)支撐車輛的十字交叉的軸,它可以驅(qū)動(dòng)車輪運(yùn)動(dòng)。驅(qū)動(dòng)橋包括:驅(qū)動(dòng)橋殼、主減速器傳動(dòng)軸、差速器、兩個(gè)半軸和末端傳動(dòng)裝置。主減速器在傳動(dòng)中的功用是增大變速器傳來(lái)的轉(zhuǎn)矩,憑借差速器把它傳遞給驅(qū)動(dòng)車輪。在汽車中主減速器傳動(dòng)軸把轉(zhuǎn)矩按正確的方向傳給驅(qū)動(dòng)輪,通常被叫做推進(jìn)器。主減速器有單級(jí)和雙級(jí)兩種形式,前者包含一對(duì)齒輪,后者包含兩對(duì)齒輪。主動(dòng)小齒輪可以和軸做成一個(gè)整體,也可以做成分開(kāi)的。從動(dòng)齒輪常做成齒圈形式,差速器殼可以用螺栓或鉚釘連接在齒圈上,主減速器的小齒輪和大齒輪可以做成螺旋齒,這樣可以在嚙合時(shí)減少噪音。雙級(jí)主減速器包含一對(duì)錐齒輪和一對(duì)圓柱齒輪,主動(dòng)齒輪帶動(dòng)從動(dòng)錐齒輪旋轉(zhuǎn)而從動(dòng)錐齒輪和小圓柱齒輪通過(guò)中間軸連在一起從而使小圓柱齒輪轉(zhuǎn)動(dòng),它與差速器殼固定在一起的大圓柱齒輪嚙合,差速器殼的旋轉(zhuǎn)帶動(dòng)差速器運(yùn)動(dòng)并和軸承裝設(shè)構(gòu)成橋殼的一部分。差速器在傳動(dòng)系中將轉(zhuǎn)矩分開(kāi)分別驅(qū)動(dòng)兩側(cè)半軸,并且允許一側(cè)驅(qū)動(dòng)輪和另一側(cè)驅(qū)動(dòng)輪以不同的角速度運(yùn)動(dòng)。差速器包括差速器殼、行星齒輪軸(十字軸),行星齒輪,側(cè)面齒輪即半軸齒輪。行星齒輪可以安裝在卡在差速器殼上的圓柱形十字軸上,并且保持與半軸齒輪的不斷嚙合。當(dāng)汽車直線行駛和在水平路面上運(yùn)動(dòng)時(shí),兩側(cè)驅(qū)動(dòng)輪將會(huì)遇到相同的滾動(dòng)阻力。在這種情況下,主減速器從動(dòng)齒輪帶動(dòng)差速器殼旋轉(zhuǎn)。當(dāng)差速器殼旋轉(zhuǎn)時(shí)差速器行星齒輪和十字軸也旋轉(zhuǎn)運(yùn)動(dòng),因?yàn)榘胼S齒輪差速器行星齒輪嚙合,半軸齒輪必須旋轉(zhuǎn),導(dǎo)致半軸與兩側(cè)車輪也運(yùn)動(dòng)。當(dāng)每一個(gè)車輪承受的阻力相等時(shí),差速器小齒輪不再旋轉(zhuǎn),它們給半軸齒輪提供相等的轉(zhuǎn)矩且兩側(cè)車輪以一個(gè)相同的角速度旋轉(zhuǎn)。當(dāng)然,當(dāng)阻力不相等時(shí),差速器行星齒輪既繞著差速器殼公轉(zhuǎn)又繞十字軸自轉(zhuǎn),如果一側(cè)半軸不旋轉(zhuǎn)時(shí),行星齒輪不會(huì)繞著固定不動(dòng)的半軸齒輪運(yùn)動(dòng),使另一側(cè)半軸齒輪以平常兩倍的速度旋轉(zhuǎn)。這樣你就明白差速器是怎么使一側(cè)齒輪轉(zhuǎn)速大于另一側(cè)的。無(wú)論什么時(shí)候汽車轉(zhuǎn)彎行駛時(shí),外側(cè)車輪總比內(nèi)側(cè)的車輪移過(guò)的距離大。內(nèi)側(cè)車輪會(huì)慢下來(lái),而外側(cè)車輪則成比例地加速,由于差速器在十字軸上自轉(zhuǎn),且在速度慢的一側(cè)的半軸齒輪上滾動(dòng),它將使外側(cè)車輪移動(dòng)的快一些。半軸內(nèi)端用花鍵與差速器半軸齒輪連接,外端用凸緣與驅(qū)動(dòng)輪輪轂相連。載貨汽車采用全浮式半軸。這樣的半軸只承受轉(zhuǎn)矩作用。其余的負(fù)載由橋殼承擔(dān),因?yàn)檩嗇炗砂惭b在橋殼上的軸支撐的。輪式拖拉機(jī)的驅(qū)動(dòng)橋一般的輪式拖拉機(jī)采用四輪驅(qū)動(dòng)的形式,它有兩個(gè)驅(qū)動(dòng)橋前驅(qū)動(dòng)橋和后驅(qū)動(dòng)橋。除了橋殼之外,兩個(gè)橋的構(gòu)造很相似。每個(gè)驅(qū)動(dòng)橋都包括橋殼,主減速器,差速器和末端傳動(dòng)裝置。前后驅(qū)動(dòng)橋可以互換,且都包含一對(duì)螺旋錐齒輪。主減速器的主動(dòng)錐齒輪與軸做成一體,并由兩對(duì)圓錐滾子軸承支撐,并用螺栓與差速器殼聯(lián)接。主動(dòng)錐齒輪凸緣外有螺紋孔與配套的螺釘,用于防止主動(dòng)錐齒輪在差速器殼作用下運(yùn)動(dòng)。關(guān)系到車軸中心線的主動(dòng)錐齒輪的位置是由裝在主動(dòng)錐齒輪后的調(diào)整墊片來(lái)調(diào)整的,裝在圓錐滾子軸承內(nèi)座圈的調(diào)整墊片用來(lái)調(diào)試安裝在主動(dòng)錐齒輪上的軸承的預(yù)緊力。齒輪軸的軸徑末端的凸緣采用一般的花鍵聯(lián)接。從動(dòng)錐齒輪用螺栓與差速器殼凸緣固定在一起。差速器包括差速器殼、四個(gè)小行星齒輪,兩側(cè)半軸齒輪。差速器殼由兩部分構(gòu)成,它們用螺栓連接在一起,并由圓錐滾子軸承裝置支撐。軸承套外面的螺母用來(lái)避免齒圈和主動(dòng)錐齒輪發(fā)生運(yùn)動(dòng)干涉,使它們正確嚙合,并調(diào)整軸承的預(yù)緊力。焊在橋殼兩端頂部的是彈簧緩沖器,每個(gè)橋殼上都有注油孔,并用油塞塞住。每個(gè)橋殼都有一個(gè)通風(fēng)孔。橋殼內(nèi)的旋轉(zhuǎn)運(yùn)動(dòng)部件都涂有潤(rùn)滑劑。在本書之中所有靠末端傳動(dòng)提供動(dòng)力的拖拉機(jī)與汽車考慮的地方有所不同。靠末端傳動(dòng)的一般用途的輪式拖拉機(jī)有的裝有輪邊減速器。當(dāng)傳來(lái)的轉(zhuǎn)矩驅(qū)動(dòng)車輪運(yùn)動(dòng)時(shí),輪邊減速器也可以增大扭矩。這些像行星般運(yùn)動(dòng)的減速齒輪裝置包括太陽(yáng)輪、行星齒輪、行星架、齒圈和減速器殼。太陽(yáng)輪用花鍵聯(lián)結(jié)在半軸外側(cè)的末端并且用鎖緊螺母擰緊固定。半軸的另一端則用花鍵聯(lián)結(jié)著半軸齒輪。圓柱行星齒輪分別與太陽(yáng)輪和齒圈嚙合,且繞裝在行星齒輪軸上的滾子軸承自轉(zhuǎn),行星齒輪軸安裝在行星架上,行星架用螺栓和螺母固定在減速器殼上。減速器殼上的凸緣,制動(dòng)鼓,輪轂,用螺栓固定在一起,行星架,減速器殼上的行星裝置的運(yùn)動(dòng)部件與驅(qū)動(dòng)輪一起旋轉(zhuǎn)運(yùn)動(dòng)。齒輪座由半軸套管上的滾子軸承支撐。半軸套管與固定的齒圈用接合套連接起來(lái),接合套有內(nèi)花鍵槽和外齒。內(nèi)花鍵槽與半軸套上的花鍵嚙合,外齒與齒圈的內(nèi)齒嚙合。太陽(yáng)輪驅(qū)動(dòng)行星齒輪運(yùn)動(dòng),并使固定的齒圈旋轉(zhuǎn)。因?yàn)樾行驱X輪軸與行星架固定在一起,所以行星齒輪可以帶動(dòng)行星架旋轉(zhuǎn),并通過(guò)減速器殼驅(qū)動(dòng)驅(qū)動(dòng)輪運(yùn)動(dòng)。輪邊減速器的部件都通過(guò)減速器殼中央的一個(gè)孔來(lái)注入潤(rùn)滑油。這個(gè)孔有量油尺并用油塞塞住。量油尺上刻有兩個(gè)痕跡,一個(gè)是減速器殼內(nèi)的最大油位,另一個(gè)是其最低油位。車輪及其保養(yǎng)現(xiàn)代的輪式拖拉機(jī)和汽車都采用充氣式輪胎,輪胎與路面接觸,汽車和拖拉機(jī)的車輪滾動(dòng)來(lái)驅(qū)動(dòng)汽車運(yùn)動(dòng)。按它們的用途分,車輪可分為乘用車用輪胎和牽引車用輪胎以及兩者相結(jié)合的類型。在貨車及一般的輪式拖拉機(jī)中,每輛車所用的輪胎型號(hào)是一樣的。農(nóng)用拖拉機(jī)后輪比前輪大,后輪承受拖拉機(jī)載重的70%,并且后輪能提供更好的牽引力。前輪承受的重量少,它比較容易轉(zhuǎn)向且提供良好的行駛方向,這是農(nóng)用車必不可少的。貨車的車輪包括輻板, 輪輞,輪輞是焊在輻板上的。當(dāng)輪輞與一個(gè)凸緣做成整體時(shí),與另一凸緣則做成可分的側(cè)擋圈,它是由分裂的擋圈支撐,一些貨車車輪只有擋圈,它包含側(cè)擋圈和鎖環(huán)。輻板上裝有車輪框架的螺栓孔,在輪轂上有雙頭螺栓,它配有螺母。在輪轂上的孔及螺母安裝在精確的位置。貨車后車橋采用雙車輪,內(nèi)側(cè)車輪有輪轂支撐并由螺母固定,螺栓兩頭都有螺紋,且內(nèi)側(cè)車輪裝有螺母,螺母上的外螺紋用鎖緊螺母固定。貨車右側(cè)車輪輻板固定螺栓用右旋螺紋,左側(cè)車輪輻板固定螺栓用左旋螺紋。這可以使汽車在行駛中螺母變緊不拖松,并且可以防止它在汽車加速或制動(dòng)時(shí)變松。汽車可沖氣式輪胎包括外胎、內(nèi)胎和墊帶。外胎有胎冠、棉布層和束帶層。輪胎在良好路面上使用的花紋細(xì)而淺,在壞路面上花紋則深而寬。橡膠輪胎內(nèi)部是中空的,它可以充氣,它裝在輪圈內(nèi)。輪胎充氣用氣門閥充氣的,它包括座筒、閥體和蓋。座筒是有黃銅做成的,它用螺栓和墊片擰緊裝在車輪輪輞上的孔內(nèi)。一些輪胎氣門閥的材料是合成的,上面用黃銅制成,下面用經(jīng)過(guò)硫化的橡膠制成的。氣門閥的內(nèi)部有一裂縫,是為了讓空氣能充入輪胎。當(dāng)氣門閥關(guān)閉時(shí),彈簧壓力和輪胎內(nèi)的空氣壓力使管子恢復(fù)原位。它包括帶橡膠環(huán)的氣門芯、活塞和彈簧。對(duì)于農(nóng)用拖拉機(jī)的驅(qū)動(dòng)和前進(jìn)輪來(lái)說(shuō),每個(gè)輪子都由輪轂,帶輪圈的輪輞,帶內(nèi)胎的輪胎的構(gòu)成。輪圈焊接在輪輞上,輪輞與輪轂用螺栓固定在一起。驅(qū)動(dòng)輪的輪胎是低壓的,胎面有深花紋,這可以獲得較好的牽引力。驅(qū)動(dòng)輪的輪轂要于半軸相適應(yīng),且能代替螺栓,使螺紋與半軸的鍵齒嚙合。轉(zhuǎn)動(dòng)螺紋可以改變輪子在半軸上的位置,獲得想得到的輪距。那樣做之前需要用千斤頂支起拖拉機(jī)的后部,并清潔與地面接觸的輪子,松開(kāi)螺栓,使其插入輪轂,如果這樣的調(diào)整還不適合,輪距可以通過(guò)使輪輞凹面向內(nèi)來(lái)進(jìn)一步加大。在一些收割機(jī)上,后輪輞與焊接在輪圈上的把手用螺栓固定在一起。在這種情況下,輪距可以通過(guò)改變?cè)诎咽稚陷嗇y螺栓的位置來(lái)改變。同樣,輪輞凹面可以朝向內(nèi)也可以朝向外。汽車和拖拉機(jī)在使用過(guò)程中遇到的問(wèn)題多數(shù)是由輪胎的狀況引起的。所以,在使用過(guò)程中,應(yīng)遵循以下規(guī)定。避免燃料或油弄到輪胎上。經(jīng)常清洗污物和胎面上英文字母縫里的沙石。盡量不要緊急制動(dòng)、不要長(zhǎng)時(shí)間不清理和避免急轉(zhuǎn)彎。這些因素會(huì)使輪胎磨損不均勻。同時(shí)也不允許驅(qū)動(dòng)輪過(guò)度滑動(dòng)。當(dāng)準(zhǔn)備長(zhǎng)時(shí)間擱置汽車時(shí),要用千斤頂頂起車輪,在車軸下放一個(gè)支架或者框架,使車輪受到的壓力得以緩解。輪胎的使用壽命是用行駛里數(shù)來(lái)表示的。對(duì)于大多數(shù)普通貨車的輪胎,它的壽命是50000Km。但是如果注意以上的規(guī)定,則可以延長(zhǎng)輪胎的使用壽命。11
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