489 活塞加工及金屬模設(shè)計(jì)
489 活塞加工及金屬模設(shè)計(jì),活塞,加工,金屬,設(shè)計(jì)
第 1 頁(yè) 共 43 頁(yè)摘要汽車(chē)發(fā)動(dòng)機(jī)的活塞是發(fā)動(dòng)機(jī)中的主要配件之一,它與活塞環(huán)、活塞銷(xiāo)等零件組成活塞組,與氣缸蓋等共同組成燃燒室,承受燃?xì)庾饔昧Σ⑼ㄟ^(guò)活塞銷(xiāo)和連桿把動(dòng)力傳給曲軸,以完成內(nèi)燃發(fā)動(dòng)機(jī)的工作過(guò)程。油氣燃燒所產(chǎn)生的熱由活塞的頂部所吸收,并傳至氣缸壁,而燃燒后氣體膨脹所產(chǎn)生的力量也必須經(jīng)由活塞來(lái)吸收,活塞會(huì)把燃燒氣體壓力及慣性力經(jīng)由連桿傳到曲軸上,利用連桿的作用將活塞的線性往復(fù)運(yùn)動(dòng)轉(zhuǎn)換曲軸的旋轉(zhuǎn)運(yùn)動(dòng)?;钊墓τ檬浅惺軞怏w壓力,井通過(guò)活塞銷(xiāo)傳給連桿驅(qū)使曲軸旋轉(zhuǎn),活塞項(xiàng)部還是燃燒室的組成部分?;钊诟邷?、高壓、高速、潤(rùn)滑不良的條件下 1二作。活塞在氣缸內(nèi)以很高的速度往復(fù)運(yùn)動(dòng),且速度在不斷地變化,這就產(chǎn)生了很大的慣性力,使活塞受到很大的附加載荷。活塞在這種惡劣的條件’卜工作,會(huì)產(chǎn)生變形并加速磨損,還會(huì)產(chǎn)生附加載荷和熱應(yīng)力,同時(shí)受到燃?xì)獾幕瘜W(xué)腐蝕作用?,F(xiàn)代的活塞設(shè)計(jì)主要有鑄造和鍛造兩種,而鑄造又比鍛造簡(jiǎn)單便宜,但卻不及鍛造活塞能承受較大的熱度和壓力。由于活塞與活塞環(huán)都必須在高溫、高壓、高速及臨界潤(rùn)滑的狀態(tài)’卜工作,因此長(zhǎng)期以來(lái),發(fā)動(dòng)機(jī)設(shè)計(jì)者都為提供一個(gè)最佳的設(shè)計(jì)而不斷努力,進(jìn)而可以從活塞方而來(lái)提高引擎的性能。本文以捷達(dá) EA113 汽油機(jī)的相關(guān)參數(shù)作為參考,對(duì)四缸汽油機(jī)的曲柄連桿機(jī)構(gòu)的主要零部件進(jìn)行了結(jié)構(gòu)設(shè)計(jì)計(jì)算,并對(duì)曲柄連桿機(jī)構(gòu)進(jìn)行了有關(guān)運(yùn)動(dòng)學(xué)和動(dòng)力學(xué)的理論分析與計(jì)算機(jī)仿真分析。首先,以運(yùn)動(dòng)學(xué)和動(dòng)力學(xué)的理論知識(shí)為依據(jù),對(duì)曲柄連桿機(jī)構(gòu)的運(yùn)動(dòng)規(guī)律以及在運(yùn)動(dòng)中的受力等問(wèn)題進(jìn)行詳盡的分析,并得到了精確的分析結(jié)果。其次分別對(duì)活塞組、連桿組以及曲軸進(jìn)行詳細(xì)的結(jié)構(gòu)設(shè)計(jì),并進(jìn)行了結(jié)構(gòu)強(qiáng)度和剛度的校核。一再次,應(yīng)用三維 CAD 軟件:Pro/Engineer 建立了曲柄連桿機(jī)構(gòu)各零部件的幾何模型,在此工作的基礎(chǔ)上,利用 Pro/E 軟件的裝配功能,將曲柄連桿機(jī)構(gòu)的各組成零件裝配成活塞組件、連桿組件和曲軸組件,然后利用 Pro/E軟件的機(jī)構(gòu)分析模塊(Pro/Mechanism),建立曲柄連桿機(jī)構(gòu)的多剛體動(dòng)力學(xué)模型,進(jìn)行運(yùn)動(dòng)學(xué)分析和動(dòng)力學(xué)分析模擬,研究了在不考慮外力作用并使曲軸保持勻速轉(zhuǎn)動(dòng)的情況下,活塞和連桿的運(yùn)動(dòng)規(guī)律以及曲柄連桿機(jī)構(gòu)的運(yùn)動(dòng)包絡(luò)。仿真結(jié)果的分析表明,仿真結(jié)果與發(fā)動(dòng)機(jī)的實(shí)際工作狀況基木一致,文章介紹的仿真方法為活塞組的結(jié)構(gòu),優(yōu)化設(shè)計(jì)提供了一種新思路。關(guān)鍵詞: 活塞 氣缸蓋 燃燒室 曲軸 慣性力 附加載荷第 2 頁(yè) 共 43 頁(yè)ABSTRACTThe piston of car motor is one of the main accessorieses in the motor ,it and the piston wreath ,piston sell etc .the spare parts constitute a piston set and cover with air cylinder etc. Constitute combustion room together , bear gas function the dint also sell through a piston and connect the pole motive song stalk to complete inside the work process of ran motor.the oil annoys the combustion produce of hot from the coping of piston absorb , and spread to air cylinder wall , and combustion empress thestrengh produced by air inflation have to also absorb through the piston , the piston will chase combustion air pressure and inertial dint through connect the spread to song stalk up , make use of connect the function of pole exercise the line back and forth of piston to convert revolving of song stalk sport.The effect of piston bears air pressure , and sell to pass to connect a pole to order about song stalk to revolve through a piston , constituting of the piston a coping still a combustion room part .piston under the condition that heat ,high pressure , high speed , lubricate bad work . The piston is exercised with very high speed back and forth in the air cylinder , and speed at constantly variety , this produced very greatly inertial inertial dint and made the piston been subjected to very big of the affixture carry a lotus . The piston is under this bad condition work , will produce to transform and accelerate to wear away , also produce affixture to carry lotus and heat in response to the dint , be subjected to chemistry of the gas corrosion function in the meantime . Modern of the piston design to mainly have the foundry forging 2 kinds , but cast again than forging simple cheapness , but cannot compare with forging piston can bear bigger heat and pressure . Piston and piston wreaths have to work under the appearance of the heat , high pressure and high speed and the critical lubrication , therefore for long time , the motor designs all continuously make great effort for providing a design , then can raise the function of from the piston .第 3 頁(yè) 共 43 頁(yè)第一章 活塞的運(yùn)行原理和工作條件2.1 活塞的運(yùn)行原理汽車(chē)發(fā)動(dòng)機(jī)的活塞是發(fā)動(dòng)機(jī)的重要配件之一,它與活塞環(huán),活塞銷(xiāo)等零件組成活塞組,與汽缸蓋等共同組成燃燒室,承受燃?xì)庾饔昧Σ⑼ㄟ^(guò)活塞銷(xiāo)和連桿把動(dòng)力傳給曲軸,以完成內(nèi)燃發(fā)動(dòng)機(jī)的工作過(guò)程。油氣燃燒所產(chǎn)生的熱由活塞的頂部所吸收,活塞會(huì)把燃燒氣體壓力及慣性力經(jīng)由連桿傳到曲軸上,利用連桿的作用將活塞的線性往復(fù)運(yùn)動(dòng)轉(zhuǎn)換成曲軸的旋轉(zhuǎn)運(yùn)動(dòng)。活塞的功用是承受氣體壓力,并通過(guò)活塞銷(xiāo)傳給連桿驅(qū)使曲軸旋轉(zhuǎn),活塞頂部還是燃燒室的組成部分。2.2 活塞的機(jī)械負(fù)荷在發(fā)動(dòng)機(jī)的工作中,活塞承受的機(jī)械載荷包括周期變化的氣體壓力、往復(fù)慣性力以及由此產(chǎn)生的側(cè)向作用力。在機(jī)械在和的作用下,活塞各部位承受各種不同的壓力:活塞頂部動(dòng)態(tài)彎曲應(yīng)力;活塞銷(xiāo)座承受拉壓及彎曲應(yīng)力;環(huán)岸承受彎曲及剪應(yīng)力。此外,在環(huán)槽部及裙部還有較大的磨損。為適應(yīng)機(jī)械負(fù)荷,設(shè)計(jì)活塞時(shí)要求各處有適合的壁厚和合理的形狀,即在保證足夠的強(qiáng)度、剛度的前提下,結(jié)構(gòu)要盡量簡(jiǎn)單、輕巧,截面變化處的過(guò)度要圓滑,以減少應(yīng)力集中。2.3 活塞的熱負(fù)荷活塞在氣缸內(nèi)工作時(shí),活塞頂面承受瞬間高溫燃?xì)獾淖饔?,燃?xì)獾淖罡邷囟瓤蛇_(dá) 2000°~2500°。因而活塞頂?shù)臏囟纫埠芨摺;钊粌H溫度高,而且溫度分布不均勻,各點(diǎn)間有很大的溫度梯度,這就成為熱應(yīng)力的根源,正式這些熱應(yīng)力對(duì)活塞頂部表面發(fā)生的開(kāi)裂起了重要作用。2.4 磨損強(qiáng)烈發(fā)動(dòng)機(jī)在工作中所產(chǎn)生的側(cè)向作用力是較大的,同時(shí),活塞在汽缸中的告訴往復(fù)運(yùn)動(dòng),活塞組與汽缸表面之間會(huì)產(chǎn)生強(qiáng)烈磨損,由于此處潤(rùn)滑條件較差,磨損情況比較嚴(yán)重。第 4 頁(yè) 共 43 頁(yè)第二章 汽油機(jī)結(jié)構(gòu)參數(shù)的選取1.1 汽缸直徑的確定根據(jù)設(shè)計(jì)任務(wù)書(shū)所提供的設(shè)計(jì)條件:所一要設(shè)計(jì)的宇氣油發(fā)動(dòng)機(jī)的排量為 2.0L.平均有效壓力: p=0.8~1.2Mpa活寨平均速度: Cmq,因此金屬型的工作溫度必然升高,所以,每澆一次,就需要將金屬型打開(kāi),停放一段時(shí)一間,待冷至規(guī)定溫度時(shí)再澆。如靠自然冷卻,需要時(shí)間較長(zhǎng),會(huì)降低生產(chǎn)率,因此常采用強(qiáng)制冷卻的方法。冷卻的方式一般有以下幾種。(1)風(fēng)冷在金屬型外圍吹風(fēng)冷卻,強(qiáng)化對(duì)流散熱,其冷卻效果與金屬型外邊的散熱而積有關(guān)。散熱而積大,冷卻效果好,故可在金屬型背而鑄出散熱片或散熱針。與沒(méi)有散熱片和散熱針的金屬型比較,冷卻效果提高 20%~30%。如果采用密封風(fēng)冷,即通壓縮空氣強(qiáng)制對(duì)流,其效果就更好。風(fēng)冷方式的金屬型,雖然結(jié)構(gòu)簡(jiǎn)單,容易制造,成本低,但冷卻效果不十分理想。(2)間接水冷在金屬型背而或某一局部,鑲鑄水套,其冷卻效果比風(fēng)冷好,適用于澆注銅件或可鍛鑄鐵件。但對(duì)澆注薄壁灰鐵鑄件或球鐵鑄件,激烈冷卻會(huì)增加鑄件的白口缺陷。為防止金屬型在背面強(qiáng)烈冷卻時(shí)所產(chǎn)生的應(yīng)力或裂紋,一般在水套與型壁之間鑲鑄異熱性好的材料。(3)直接水冷在金屬型的背而或局部直接制出水套,在水套內(nèi)進(jìn)行冷卻,這主要用于澆注鋼件或其他合金鑄件,鑄型要求強(qiáng)烈冷卻的部位。由于向型壁直接噴水,很快將熱量帶走,冷卻效果很好。由于直接冷卻,金屬型產(chǎn)生的熱應(yīng)力大,故不宜用易裂材料(鑄鐵)制作,一般用碳鋼或合金鋼制造金屬型,因此成本高,只適用于大批量生產(chǎn)。6.4 金屬型芯的設(shè)計(jì)設(shè)計(jì)為組合型芯第 27 頁(yè) 共 43 頁(yè)由兩側(cè)的單型芯和中間芯組成,方便從毛柸中取出型芯。中間芯寬 18,單型芯底部寬 15.第 28 頁(yè) 共 43 頁(yè)總結(jié)通過(guò)為期十四周的畢業(yè)設(shè)計(jì),使我收獲了很多東西。不但學(xué)到了很多有用的知識(shí),還學(xué)到很多從書(shū)本上無(wú)法學(xué)習(xí)到的東西,像編程經(jīng)驗(yàn)、調(diào)錯(cuò)能力、理論與實(shí)際相結(jié)合、獨(dú)立動(dòng)手能力等等,既開(kāi)闊了視野,增長(zhǎng)了知識(shí),又鍛煉了自己,同時(shí)也認(rèn)識(shí)到了自己的不足。通過(guò)一段時(shí)間的努力終一于克服了困難,拿出了自己的作品。發(fā)現(xiàn)知識(shí)的增長(zhǎng)果然是個(gè)艱苦的過(guò)程。指導(dǎo)老師周里群老師給予了我悉心的指導(dǎo),在整個(gè)畢業(yè)設(shè)計(jì)的過(guò)程中,周老師從方方而而都給予幫助和支持。從畢業(yè)設(shè)計(jì)任務(wù)的提出到最終論文的審閱批改,在每一細(xì)節(jié)上,周老師都細(xì)心的指異,設(shè)計(jì)中遇到的許多問(wèn)題,也是在周老師的幫助下得以解決,使我的畢業(yè)設(shè)計(jì)能夠順利完成。在此表示衷心的感謝。周老師嚴(yán)謹(jǐn)細(xì)致、一絲不茍的作風(fēng)一直是我工作、學(xué)習(xí)中的榜樣;他們循循善誘的教異和不拘一格的思路給予我無(wú)盡的啟迪。同時(shí)也非常感謝的幾位同學(xué),他們同樣給予了我很大的幫助。第 29 頁(yè) 共 43 頁(yè)參考文獻(xiàn)[1].宮克強(qiáng)特種鑄造北京:機(jī)械工業(yè)出版社,1982[2].耿鑫明鋁合金金屬型鑄造北京:國(guó)防工業(yè)出版社,1976[3].王瑞芳金工實(shí)習(xí)北京:機(jī)械工業(yè)出版社,2001[4].丁陽(yáng)喜機(jī)械制造及其自動(dòng)化生產(chǎn)實(shí)習(xí)教程北京;中國(guó)鐵道出版社,2002[5].胡傳忻.熱加工手冊(cè).北京:北京工業(yè)大學(xué)出版社,2002[6].北京機(jī)械工程學(xué)會(huì)鑄造專(zhuān)業(yè)學(xué)會(huì)編.鑄造技術(shù)數(shù)據(jù)手冊(cè).北京:機(jī)械工業(yè)出版社,1993[7].曹巖,李建華.solidworks2004 產(chǎn)品設(shè)計(jì)實(shí)例精解.北京:機(jī)械工業(yè)出版社,2004.[8].哈爾濱工業(yè)大學(xué).鑄造工藝學(xué).北京:機(jī)械工業(yè)出版社,1985[9].鑄造專(zhuān)業(yè)學(xué)會(huì).鑄造技術(shù)數(shù)據(jù)手冊(cè).北京:機(jī)械工業(yè)出版社,1993[10].賈策,李漢明.solidworks2001 實(shí)踐與提高.重慶:重慶大學(xué)出版社,2001[11].吳宗澤,羅圣國(guó).機(jī)械設(shè)計(jì)課程設(shè)計(jì)手冊(cè).北京:高等教育出版社,2003第 30 頁(yè) 共 43 頁(yè)附錄:英文技術(shù)資料及其翻譯 1.中文翻譯汽車(chē)發(fā)動(dòng)機(jī)活塞材質(zhì)的選取及發(fā)展趨勢(shì)活塞被稱(chēng)為發(fā)動(dòng)機(jī)的心臟。它是發(fā)動(dòng)機(jī)中最重要的零件之一。其功用是承受氣體壓力,并通過(guò)活塞銷(xiāo)傳給連桿驅(qū)使曲軸旋轉(zhuǎn)。在發(fā)動(dòng)機(jī)工作時(shí),活塞直接與瞬時(shí)溫度 2200 攝氏度的高溫氣體接觸,其頂部溫度達(dá) 3008,且溫度分布不均勻;在做功行程時(shí)活寨頂部承受著很大的氣體壓力,汽油機(jī)達(dá) 4MPa 一5MPa,柴油機(jī)高達(dá) 8MPa 一 9MPa ,甚至更高;此外,活塞在氣缸內(nèi)往復(fù)運(yùn)動(dòng)線速度可達(dá),l1m/s 一 16m/s;在這種惡劣的條件下工作?;钊惺苤邷亍⒏邏旱臒嶝?fù)荷和機(jī)械負(fù)荷。因此活塞作為汽車(chē)發(fā)動(dòng)機(jī)中傳遞能量的一個(gè)非常重要的構(gòu)件,對(duì)其材料具有特殊的要求:密度小、質(zhì)量輕、熱傳導(dǎo)性好、熱膨脹系數(shù)小;并具有足夠的高溫強(qiáng)度、耐磨和耐蝕性能、尺寸穩(wěn)定性好。另外還應(yīng)具有容易制造、成本低廉的特點(diǎn)。伴隨著汽車(chē)發(fā)動(dòng)機(jī)的不斷發(fā)展與進(jìn)步,人們對(duì)活塞材料的研究與應(yīng)用也取得了長(zhǎng)足的發(fā)展。鋁合金活塞材料的發(fā)展應(yīng)用概況世界上最旱的汽車(chē)發(fā)動(dòng)機(jī)活塞是鑄鐵的。1911 年,鋁合金材料以其質(zhì)輕、良好熱傳導(dǎo)性以及較低的熱膨脹系數(shù)等特點(diǎn)的得到人們的關(guān)注并開(kāi)始用于制造活塞。1920 年一種 Al-Cu-NI-Mg 系合金正式成功地應(yīng)用于汽車(chē)發(fā)動(dòng)機(jī)活寨,從而證明了鑄造鋁合金作者簡(jiǎn)介:1、Al-Cu-NI-Mg 系合金該系合金于 1920 年開(kāi)始就在英國(guó)得到應(yīng)用。其典型合金代號(hào)有 LMI4(英)、SAE39}美)、AC5A(日)。該類(lèi)合金的優(yōu)點(diǎn)是良好的高溫強(qiáng)度、導(dǎo)熱性、延伸率及耐磨性;但囚其線膨脹系數(shù)和密度較大,鑄造性能差且含有較多貴重金屬價(jià)格較貴而被淘汰。2、Al-Cu-Si 系合金這類(lèi)合金的優(yōu)點(diǎn)是:由于含有一定量的硅,鑄造性能較好,切削加工性能一也有所改善;在常溫和高溫下均有較好的機(jī)械、物理性能。在 70 年代之前,該類(lèi)合金曾是前蘇聯(lián)等國(guó)應(yīng)用最廣泛的一種材料,我國(guó)的解放牌CAIOA,CAIOB,CAIOC 型汽車(chē)活塞一也采用此合金。其典型合金代號(hào)有 SAE300(美)、A110B(俄)、AC2A(日)。該類(lèi)合金的缺點(diǎn)是:線膨脹系數(shù)較大,因含有較多的Cu,所以體積穩(wěn)定性不好,會(huì)產(chǎn)生永久性“長(zhǎng)大”現(xiàn)象引起活塞“咬缸” ,所以國(guó)內(nèi)現(xiàn)已停止使用這類(lèi)材料。3、AI-Si 合金第 31 頁(yè) 共 43 頁(yè)由于 AI-Si 合金線脹系數(shù)小、比熏小,耐磨性好,鑄造性能好等一系列優(yōu)點(diǎn)而成為應(yīng)用于現(xiàn)代發(fā)動(dòng)機(jī)活塞制造最廣泛的材料。這類(lèi)合金按含 Si 量的高低可分為共(業(yè))晶型和過(guò)共晶型兩大類(lèi)。4、共晶(亞共晶)型 AI-Si 合金國(guó)內(nèi)外輕、巾型汽車(chē)汽、柴油發(fā)動(dòng)機(jī)以及轎車(chē)發(fā)動(dòng)機(jī)活塞大多采用了共晶(亞共晶)型 AI-Si 合金。具有代表性的共晶(亞共晶)型 AI-Si 合金活塞材料的牌號(hào)及化學(xué)成分見(jiàn)表 1。該類(lèi)合金含 I 量一般在 8.5%一 13%,為了提高合金的室溫及高溫性能在其中加入了 Cu Mg Mn Ni 等合金元素進(jìn)行多元合金化。表2 所列為共晶(亞共晶)型 Al 一 Si 合金活塞材料常溫和高溫性能。合金中的 Cu 可提高合金的常溫及高溫強(qiáng)度,改善合金切削加工性能及表面光潔度;但 Cu 量過(guò)多會(huì)使合金密度增大,熱裂傾向增大,耐蝕性降低,鑄造性能變壞,同時(shí)還使合金成本增加。囚而作為活塞用的 AI-Si 合金應(yīng)在保證其強(qiáng)度的前提下盡川一能降低含銅量。Mg 也是 AI-Si 合金中提高合金強(qiáng)度的重要元素,特別是與 CU 配合使用時(shí)可進(jìn)一步提高合金耐熱性。但 Mg 加入量過(guò)多時(shí)易在晶界上形成脆性相,反而降低了合金強(qiáng)度。另外 Mg 還可能造成鑄件夾渣,所以 Mg 的加入量一般控制在0.4%一 1.5%。國(guó)內(nèi)廠家多控制在 0.7%一 1.0%之間。Mn 可以提高合金的熱穩(wěn)定性、高溫持久強(qiáng)度和使度,同時(shí)還’閨一以減少雜質(zhì)元素對(duì)鐵的危害。但加入過(guò)多的 Mn 會(huì)形成粗大脆性化合物,反而降低合金強(qiáng)度。Mn 的加入量多控制在 1%以下。國(guó)外資料認(rèn)為。Ni 可以提高合金的高溫強(qiáng)度及合金熱穩(wěn)定性。如含有 Ni的 ZLI09 比不合 Ni 的 ZLI08 體積穩(wěn)定性好。這對(duì)活塞這種零件來(lái)說(shuō)是非常有意義的。但近年來(lái)的一些試驗(yàn)研究又表明:加 Ni 對(duì)合金的高溫性能并無(wú)顯著提高國(guó)內(nèi)外汽車(chē)發(fā)動(dòng)機(jī)活塞材料的發(fā)展及應(yīng)用由于鋁硅合金中 Si 含量超過(guò) 6%一 8%時(shí),組織中便會(huì)出現(xiàn)粗針狀共晶硅組織,使合金的機(jī)械性能降低。因此,共晶(亞共晶)型 AI-Si 合金需進(jìn)行變質(zhì)處理。共晶硅常用的變質(zhì)元素有 Na Sr P Sb RE 等,其中國(guó)內(nèi)應(yīng)用較多的是Na 鹽變質(zhì),效果良好。但 Na 款變質(zhì)有效時(shí)間較短。同時(shí)還會(huì)腐蝕增竭給生產(chǎn)帶來(lái)不便。Sr 有較強(qiáng)的變質(zhì)作用和足夠·長(zhǎng)的變質(zhì)有效期,但 r 較貴且變質(zhì)時(shí)會(huì)增加合金吸氣,故目前還不能取代 Na。目前,對(duì)于共晶型 I-i 合金來(lái)說(shuō)(如ZLID9}更多地采用了磷變質(zhì)劑以代替 Na 變質(zhì),且磷變質(zhì)效果優(yōu)于 Na 鹽變質(zhì)而被國(guó)內(nèi)眾多活塞制造廠推廣使用?,F(xiàn)在在汽車(chē)發(fā)動(dòng)機(jī)上應(yīng)用最廣泛的 AI-Si.活塞材料為 ZLIQ9(GMahlel24,AC8A),國(guó)外著名發(fā)動(dòng)機(jī)制造廠(如 Cummins Renault 等)和國(guó)內(nèi)玉柴、錫柴等發(fā)動(dòng)機(jī)制造第 32 頁(yè) 共 43 頁(yè)廠均采用該材料制造的活塞。共晶型 AI-Si 合金隨著發(fā)動(dòng)機(jī)對(duì)功率、扭矩、噪聲、排放的要求越來(lái)越高,共晶(亞共晶)型AI-Si 合金已難以達(dá)到使用性能要求。因此,人們把目光投向另一種更為理想的活塞材料—過(guò)共晶型 AI-Si 合金。這類(lèi)合金含 Si 量高達(dá) 17%一 26%,而隨著Si 含量的增加,合金的線脹系數(shù)減小,耐磨性和體積穩(wěn)定性相應(yīng)提高,且合金密度也隨之減小,用其制造發(fā)動(dòng)機(jī)活塞,可在設(shè)計(jì)上縮小氣缸筒內(nèi)壁與活塞之問(wèn)的問(wèn)隙,從而提高發(fā)動(dòng)機(jī)效率.因此受到世界各國(guó)研究者的重視[3]國(guó)外對(duì)過(guò)共晶型 AI-Si 合金的研究應(yīng)用較早,使用范圍已從摩托車(chē)活塞擴(kuò)大到載貨汽車(chē)的活塞上。國(guó)內(nèi)近些年也對(duì)該類(lèi)活塞材料進(jìn)行了大量的研究,但實(shí)際應(yīng)用的還較少。國(guó)內(nèi)外具有代表性的過(guò)共晶 AI-Si 合金牌號(hào)及化學(xué)成分見(jiàn)表 3。表 4 為過(guò)共晶型 AI-Si 合金活寨材料常溫和高溫性能對(duì)比。過(guò)共晶型活塞合金按 Si 的含量分為三組:組一為 17%一 19%,組二為 20%一 23%,組三為 24%一 26%。一二組工藝性較好,在實(shí)際生產(chǎn)中應(yīng)用較多;第三組由于 si 含量高,結(jié)晶范圍大,鑄造工藝性能很差,初晶 Si 的變質(zhì)困難。為保證合金滿足活塞性能要求。也在其中加入 Cu、Mg、Mn Ni Ti RE 等等.所起作用與共晶型合金中基本相同。新型鋁合金活塞材料的研究及應(yīng)用美國(guó)航空航天局(NASA)馬歇爾空間飛行中心(MSFC)兩位美籍華人科學(xué)家發(fā)明了一種名為 MS-FC-388 高強(qiáng)度鋁合金,用于制造 EvinrudeE 一下 TECTM 外置發(fā)動(dòng)機(jī)活塞,取得了十分令人滿意效果與經(jīng)濟(jì)效益。其特點(diǎn)是:發(fā)動(dòng)機(jī)的噪聲大幅度下降,排放的污染顯著減少,燃料效率大為提高,使用壽命顯著延·長(zhǎng),比普通的常規(guī)活塞鋁合金的強(qiáng)度高 1.5 倍,生產(chǎn)材料成本比常規(guī)合金的低 2.21美元/Kg,在 260~370℃仍有令人驚奇的強(qiáng)度。該新型鋁合金不但滿足汽車(chē)工業(yè)低排放污染物的要求,而且能滿足航天器在高溫下有很強(qiáng)的耐腐蝕性的要求。此外,國(guó)外許多發(fā)動(dòng)機(jī)制造商采用鍛造鋁合金 2618(LD7)用于制造各種高級(jí)轎車(chē)及賽車(chē)發(fā)動(dòng)機(jī)活塞。圖 4 所示為應(yīng)用于 Ford 發(fā)動(dòng)機(jī)上的鍛造活塞,圖 5 為Chrysler 汽車(chē)發(fā)動(dòng)機(jī)鍛鋁活塞。國(guó)內(nèi)外汽車(chē)發(fā)動(dòng)機(jī)活塞材料的發(fā)展及應(yīng)用鋁基復(fù)合材料的研究及應(yīng)用在滿足內(nèi)燃機(jī)輕量小型化、可靠性和耐久性的情況下,發(fā)動(dòng)機(jī)向著高速、大功率、大壓縮比的方向發(fā)展,其燃燒室內(nèi)溫度和壓力變得更高,以往使用的鋁合金已達(dá)到或接近使用極限。為此,鋁基復(fù)合材料活塞的開(kāi)發(fā)近年來(lái)受到了高度重視[[4]美、日及歐洲工業(yè)發(fā)達(dá)國(guó)家在這方面已取得了重要進(jìn)展,并在車(chē)用柴油機(jī)上迅速得到了推廣。第 33 頁(yè) 共 43 頁(yè)1)碳化硅顆粒增強(qiáng)鑄鋁活塞粒度為 5um-10um,含量為 5%一 7%的 SIC 陶瓷顆粒,經(jīng)過(guò)特殊處理后用流變鑄造法加入到 ZL I}中然后擠壓鑄造成型, ’可用于活塞的整體或局部增強(qiáng)。該材料的熱導(dǎo)率及熱膨脹系數(shù)各為 0. 32w/(m 和 18x10-6/C)。國(guó)內(nèi)研制的碳化硅顆粒局部增強(qiáng)鋁合金活。塞經(jīng)上海 50 型拖拉機(jī)田間試驗(yàn)證明,第一道環(huán)槽導(dǎo)熱得到了較大改善,燃燒喉口得到加強(qiáng),耐磨性比鑲奧氏體鑄鐵圈的活塞要好,活塞質(zhì)量也得到了加強(qiáng)。2)氧化鋁、硅酸鋁和硼酸鋁短纖增強(qiáng)鋁合金活塞(CFR)該材料采用陶瓷纖維氧化鋁或硅酸鋁、硼酸鋁短纖維增強(qiáng)基體材料(一般為共晶性或亞共晶性 Al 一 Si 合金)的活塞(CFR 活塞),與基體鋁合金相比,在300℃時(shí)的抗拉強(qiáng)度極限提高 20%以上,熱膨脹系數(shù)降低 15%,導(dǎo)熱率降低25%,而密度基本不變,耐磨性能優(yōu)異,熱穩(wěn)定性好、具有更好的高溫綜合性能[6]。采用擠壓鑄造工藝生產(chǎn)的局部增強(qiáng)復(fù)合材料活塞,界面結(jié)合牢固可靠,成品率高,工藝寬容好,特別適合于經(jīng)增壓、強(qiáng)化的工作條件苛刻的柴油發(fā)動(dòng)機(jī)。目前,硼酸鋁單晶纖維團(tuán)粒化坯體,強(qiáng)化活塞第一道環(huán)槽和頂部的二沖程汽油機(jī)用鋁基復(fù)合材料活塞,已經(jīng)在舷外機(jī)和摩托雪橇上得到了應(yīng)用。國(guó)外日本豐田 ART 公司以年產(chǎn) C FR 活塞達(dá)百萬(wàn)只 l}l:國(guó)內(nèi)東南大學(xué)材料學(xué)院與躍進(jìn)集團(tuán)及南京金陵汽車(chē)配件廠合作的 NJ433 發(fā)動(dòng)機(jī)采用增強(qiáng)基體材料的活塞,通過(guò)了 1000 小時(shí)臺(tái)架試驗(yàn);與玉柴機(jī)器公司、德國(guó)馬勒(南京)公司合作的 YC6112發(fā)動(dòng)機(jī)活塞頂部燃燒室周邊增強(qiáng),現(xiàn)已通過(guò)一系列試驗(yàn)及技術(shù)鑒定并達(dá)到批量化生產(chǎn),迄今已經(jīng)生產(chǎn)復(fù)合材料活塞毛坯 20 萬(wàn)件。形成年產(chǎn)數(shù)千萬(wàn)元的復(fù)合材料活塞產(chǎn)業(yè),使陶瓷纖維增強(qiáng)鋁基復(fù)合材料在我國(guó)的汽車(chē)發(fā)動(dòng)機(jī)行業(yè)進(jìn)入了工業(yè)應(yīng)用階段。3)國(guó)內(nèi)外其它活塞材料的研究應(yīng)用隨著大馬力汽車(chē)發(fā)動(dòng)機(jī)快速發(fā)展,尤其是重型柴油發(fā)動(dòng)機(jī)渦輪增壓、中冷技術(shù)的應(yīng)用以及大缸徑高壓縮比、低排放要求的不斷提高。傳統(tǒng)鋁合金活塞材料已無(wú)法滿足其使用要求,因而國(guó)內(nèi)外眾多活塞材料研究機(jī)構(gòu)和制造商推出了許多新型活塞材料。鋼頂鋁裙材料與鑄鋁和比,鑄鋼的機(jī)械強(qiáng)度高、耐磨性能好,但加工麻煩,密度大,成本高,對(duì)缸套的磨損嚴(yán)重。因此很少全部用鑄鋼做活塞,而是在一些強(qiáng)化程度高的柴油機(jī)上用鑄造合金鋼(如 40CrMn, 4CrlDSi2Mo)做活塞頭部,用鑄鋁做活第 34 頁(yè) 共 43 頁(yè)塞裙部,從而構(gòu)成了所謂的鋼頂鋁裙的組合式活寨。該結(jié)構(gòu)的活塞已經(jīng)在超長(zhǎng)沖程的 L-G}/GBE 系列的低迷發(fā)動(dòng)機(jī)上得到了應(yīng)用。法國(guó) Renault 公司制造的重型商用車(chē)用 420 馬力 dill 發(fā)動(dòng)機(jī)也采用了這種結(jié)構(gòu)的活塞。圖 6 所示為德國(guó)Mahel 活塞有限公司制造的重型商用車(chē)用鋼頂鋁裙的組合式活塞。陶瓷材料陶瓷是各種氧化物、氮化物、碳化物等無(wú)機(jī)非金屬材料的通稱(chēng)。全陶瓷活塞目前還無(wú)成功的應(yīng)用實(shí)例,但織合式陶瓷活塞已在特種發(fā)動(dòng)機(jī)上得到了一定的應(yīng)用。五十鈴汽車(chē)公司所研制的絕熱發(fā)動(dòng)機(jī)已運(yùn)行了 3500h。據(jù)介紹,它的活塞是采用 Si3N4 活塞頭部,用一鋼卡環(huán)與鑄鐵裙部連接,頭部與裙部之間設(shè)置空氣隙,并安裝一隔熱襯墊。這種設(shè)計(jì)的活塞隔熱效果較佳,頭部最高溫度為 700℃,裙部卻只有 100℃~200℃。但由于陶瓷的性能特點(diǎn)、復(fù)雜的制造技術(shù)和高成本,要使陶瓷活塞大規(guī)模地應(yīng)用于內(nèi)燃機(jī),還需要做許多研究工作。樹(shù)脂基復(fù)合材料樹(shù)脂基復(fù)合材料作為一種新型的工程材料已廣泛應(yīng)用于國(guó)民經(jīng)濟(jì)的許多領(lǐng)域,如鑄造用的玻璃纖維增強(qiáng)塑料模具和軍工用的導(dǎo)彈頭錐。美國(guó)西密歇根大學(xué)采用 30%短切石墨纖維增強(qiáng)聚酞業(yè)胺樹(shù)脂基復(fù)合材料(260℃下抗拉強(qiáng)度可達(dá)102MPa,延伸率僅為 7.2%)制造活塞。囚此材料的耐熱溫度較低,故在活寨頂部等離子噴涂了一層 Mg 一 A1203 尖晶石熱障涂層。爾后將該活塞裝在了功率為3 .7kw 轉(zhuǎn)速為 3800r/m 的二沖程風(fēng)冷小型發(fā)動(dòng)機(jī)上進(jìn)行了 1500 小時(shí)臺(tái)架試驗(yàn)。盡管活塞頂部出現(xiàn)燒蝕,但該復(fù)合材料在制造小型活塞仍具有一定的生命力。碳及碳纖維增強(qiáng)碳基復(fù)合材料石墨具有自潤(rùn)滑性好、導(dǎo)熱率高、耐熱性能優(yōu)良、尺一寸穩(wěn)定性好、熱膨脹系數(shù)小、體積密度低等特點(diǎn)。但普通石墨的力學(xué)性能不高,使其在活塞材料上一直難于應(yīng)用。隨著等靜壓成型技術(shù)和細(xì)結(jié)構(gòu)高強(qiáng)度石噩的發(fā)明,綜合性能良好的高強(qiáng)度石墨材料在活塞上的應(yīng)用才真正具有了可能性和現(xiàn)實(shí)性。碳纖維增強(qiáng)碳基復(fù)合材料除了石墨材料所具有的一切理化性能外具有最優(yōu)異的高溫性能—在 1700~C 的惰性環(huán)境下抗彎強(qiáng)度為 571.9MPa。美國(guó)賽車(chē)公司在 2 .4KW發(fā)動(dòng)機(jī) 32 小時(shí)全負(fù)荷性能臺(tái)架試驗(yàn)中發(fā)現(xiàn)碳纖維增強(qiáng)碳基復(fù)合材料的活塞明顯優(yōu)于鋁合金活寨,且活塞頂面完好無(wú)損。其成本分析報(bào)告指出:按年產(chǎn) 25 萬(wàn)只碳基復(fù)合材料的活塞計(jì)算.每只活塞成本為 14 美元,如果將年產(chǎn)量擴(kuò)至 100 萬(wàn)只則單只活塞成本可降到 9.1 美元,而鋁合金活塞的單只成本為 6 一 12 美元,由此一可見(jiàn),碳基復(fù)合材料活塞有著廣闊的應(yīng)用前景。結(jié)束語(yǔ)現(xiàn)代道路交通設(shè)施的完善以及物資流通速度的加快促使汽車(chē)工業(yè)制造出快第 35 頁(yè) 共 43 頁(yè)速、高效的交通運(yùn)輸工具而對(duì)汽車(chē)發(fā)動(dòng)機(jī)提出了更高的要求:提高發(fā)動(dòng)機(jī)轉(zhuǎn)速和功率一活塞工作速度達(dá) 11m/s~16m/s,功率達(dá)到 450 馬力或更高。隨著汽車(chē)發(fā)動(dòng)機(jī)向高速化、大功率方向的發(fā)展,活塞材料除對(duì)常溫強(qiáng)度、使度、延伸率、熱膨脹系數(shù)等性能要求不斷提高外,還對(duì)其高溫性能(如高溫拉伸強(qiáng)度、高溫疲勞強(qiáng)度、導(dǎo)熱率)及耐磨性能提出了更高的要求。因此合理選擇活寒制造材料對(duì)于新型發(fā)動(dòng)機(jī)的開(kāi)發(fā)至關(guān)重要。對(duì)于輕、中型汽車(chē)及轎車(chē)用發(fā)動(dòng)機(jī)來(lái)說(shuō),共晶(亞共晶)AI-Si 合金以其良好的材料綜合性能仍然是制造活塞的’首選材料;對(duì)于重型大馬力發(fā)動(dòng)機(jī)而言,鋼頂鋁裙材料的活塞已經(jīng)得到大量應(yīng)用,而在眾多活塞新材料中過(guò)共晶 Al-Si合金、鋁基復(fù)合材料以及碳纖維增強(qiáng)碳基復(fù)合材料均以其優(yōu)良的材料綜合性能以及關(guān)鍵技術(shù)的突破、逐步降低的制造成本等優(yōu)點(diǎn)而最具發(fā)展前途。第 36 頁(yè) 共 43 頁(yè)2.英文技術(shù)資料Automobile engine piston material selection and development trendThe piston is called the engine's heart. It is the most important parts in the engine of one. Its function is withstanding gas pressure, and driven by the piston pin to crankshaft connecting. When the engine work directly with transient temperature, the pistons 22 degrees Celsius temperature gas contact, the top temperatures reached 3008 and temperature distribution uneven; In power stroke ZhaiDing department live under a lot of gas pressure, 4MPa a gasoline engine 5MPa, diesel engine of 8MPa a 9MPa, as even higher; In addition, the piston cylinder reciprocating movement in linear can reach, l1m/s a dedicated 16m/s; In this harsh conditions work. The piston under high temperature and high pressure the heat load and mechanical load. Therefore the pistons as automobile engine transmission of energy a very important component of its material, has special requirements: density is small, light quality, thermal conductivity, good thermal expansion coefficient little; And have enough of the high temperature strength, wear and corrosion resistance, dimension stability is good. Also should have easy to manufacture and cheap characteristics. With the continuous development of automobile engine with progress, people on the research and application of the piston material have also made considerable development.The development and application of aluminium alloy piston material profilesThe world's most drought car engine piston is cast iron. In 1911, aluminum alloy material with its light, good low thermal conductivity and characteristics of thermal expansion coefficient of the focus of people's attention, and began to get used to manufacture the piston. 1920 a Cu Al - NI - Mg department alloy - officially applied successfully in the automobile engine village, so as to prove the live cast aluminium author introduction:1, Cu - NI Al - of Mg alloy.The department alloy in 1920 start applied in Britain. Its typical alloy code LMI4 (English), there SAE39} beauty), AC5A (date). This alloy is the advantage of good high strength, thermal conductivity, elongation and wear resistance; But its expansion coefficient and the density of the prisoner larger, casting performance is poor and contain more precious metal price is more expensive and be eliminated.第 37 頁(yè) 共 43 頁(yè)2, Cu - Si Al - of alloysThis kind of alloy advantage is: because it contains a certain amount of silicon, casting performance is better, machinability a also improved; In normal temperature and high temperatures are good mechanical and physical properties. In the 1970s, this alloy was before the former Soviet union and other countries the most widely used a kind of material, our XieFangPai CAIOA, CAIOB, CAIOC type automobile pistons also USES this alloy a. Its typical alloy code have SAE300 (USA), A110B (Russia), AC2A (date). This alloy steels are defect is: larger, because contain more Cu, so volume stability is bad, will produce permanent "grow up" phenomenon caused by the piston "bite cylinder", therefore the domestic has stopped using this kind of material.3, AI - Si alloysBecause the AI - Si alloy linear expansion coefficient than fume small, small, good abrasion resistance, casting performance and so on a series of advantage and be used in modern engine pistons manufacturing the most extensive materials. This kind of alloy according to the discretion of containing Si quantity can be divided into altogether (industry) crystal and eutectic type two kinds big.4, eutectic (the eutectic) type AI - Si alloysDomestic and international light, towel type car gasoline and diesel engine and car engine piston is used mostly the eutectic (the eutectic) type AI - Si alloys. The typical eutectic (the eutectic) type AI - Si alloy piston material grades and the chemical constituents see table 1. These alloys containing I quantity in 8.5% a 13%, general to improve performance and high temperature alloy in which joined Cu Mg alloy elements such as Ni Mn multivariate alloying. Table 2 listed eutectic (the eutectic) type piston material Al a Si alloy normal temperature and high temperature performance.The alloy can improve the Cu alloy is normal and high temperature strength, improve the alloy cutting processing properties and surface finish; But too Cu amount will make alloy density increases, hot tear tendency increases, corrosion resistance is reduced, casting performance becomes worse, also make alloy costs. And as a prison with AI - Si piston in guarantee its strength alloy should be under the premise of a can reduce as sichuan contain copper quantity.Mg is AI - Si alloy improve alloy strength of importance chemical element, 第 38 頁(yè) 共 43 頁(yè)especially when used together with CU alloy heat resistance may be further improved. But Mg addition amount in too easily formed on grain boundary brittle phase, the decline in alloy intensity. Another Mg may also cause casting slag, so Mg addition amount general control in 0.4% a 1.5%. Domestic manufacturer is much control in 0.7% a between 1.0%.Mn can improve the thermal stability, high temperature alloy lasting strength and make degrees, also 'maiden a to reduce the harm of iron impurity element. But to join too many Mn can form bulky brittle compounds, but reduce alloy intensity. Mn's addition amount control under 1%.Foreign material think. Ni can improve alloy temperature strength and alloy thermal stability. If the ZLI09 containing Ni Ni than not ZLI08 volume stability of. The pistons for this part is very significant. But in recent years that some of the experimental research and to alloy: addition Ni high-temperature performance and no significant improvementDomestic and foreign automobile engine development and application of the piston materialBecause al-si alloy Si content in a more than 6% of 8%, organization will appear thick needle eutectic silicon organizations, the mechanical properties of the reduced. Alloy Therefore, eutectic (the eutectic) type AI - Si alloy need to undertake modification. Eutectic silicon common metamorphic elements have making Sr P Sb RE etc, with domestic application more is deteriorating, making good results. Salt But making money metamorphic effective time is short. Also will increase to production safflowerfraie corrosion inconvenience. Sr has the strong metamorphism and enough, but the validity, long metamorphism is expensive and metamorphic when r increased, so is still alloy inspiratory making cannot replace. At present, for eutectic type I - I alloy ZLID9} it (such as more adopted in lieu of phosphorus metamorphic agent making metamorphism, and phosphorus metamorphic effect is better than by making salt metamorphic popularize the use of domestic numerous piston manufacturer.Now in the most widely used car engine on the AI - Si. ZLIQ9 (piston material GMahlel24, for AC8A), foreign famous Cummins engine manufacturer (such as Renault, etc.) and domestic yuchai, tin wood are used as engine manufacturer the material made the pistons.第 39 頁(yè) 共 43 頁(yè)Eutectic type AI - Si alloysWith the engine to power, torque, noise, emission requirements more and more high, eutectic (the eutectic) type AI - has been difficult to achieve Si alloy using performance requirements. Therefore, people look to another kind of more ideal piston material - after eutectic type AI - Si alloys. This kind of alloy contain Si quantity as much as 17% a 26%, and with the increase of the content of Si coefficient of linear expansion, alloy decreases accordingly, wear resistance and volume stability improved and alloy decreases, use with density and the manufacturing engine piston, can design on the narrowing of the piston and cylinder tube wall, and ask asked gap. Therefore improve engine efficiency by world researchers' attention [3] foreign across eutectic type AI - Si alloy earlier, research and application of use scope has been expanded to bills from motorcycle Detroit auto piston. In recent years for this type of domestic piston material also done a lot of research, but less is of practical application. Domestic and foreign representative had eutectic AI - Si alloy nameplate and chemical composition table 3. Table 4 for eutectic type AI - Si alloy live village materials normal temperature and high temperature performance comparison. After eutectic type piston alloy press Si content is divided into three groups: group one for 17% a 19%, 20% of a 23%, group redquin three 24% a 26%. 123 group good workmanship, applied in practical production more; The third group, due to high levels of si crystallization casting property range, very poorly, the metamorphic difficult w
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