外文翻譯--傳動(dòng)系統(tǒng)【中英文文獻(xiàn)譯文】,中英文文獻(xiàn)譯文,外文,翻譯,傳動(dòng)系統(tǒng),中英文,文獻(xiàn),譯文 中北大學(xué)信息商務(wù)學(xué)院2016屆畢業(yè)設(shè)計(jì)說(shuō)明書(shū) 傳動(dòng)系統(tǒng) 1 基本傳動(dòng)系統(tǒng)的組成部份 傳動(dòng)系統(tǒng)是將發(fā)動(dòng)機(jī)動(dòng)力轉(zhuǎn)移到驅(qū)動(dòng)輪的結(jié)構(gòu)。主要的結(jié)構(gòu)和目的是： 1.1 離合器 --- 分離驅(qū)動(dòng)； --- 平順的接合驅(qū)動(dòng)； 1.2 變速器 --- 增加提供給驅(qū)動(dòng)輪的轉(zhuǎn)矩； --- 使發(fā)動(dòng)機(jī)能夠在給定的速度范圍里面運(yùn)轉(zhuǎn)而不考慮的車(chē)速； --- 使車(chē)輛的作倒退運(yùn)動(dòng)； --- 提供一個(gè)齒輪的空檔以便發(fā)動(dòng)機(jī)能不需要移動(dòng)車(chē)輛就運(yùn)轉(zhuǎn)； 1.3 減速器 --- 使驅(qū)動(dòng)轉(zhuǎn)向90 °； --- 減少一定的驅(qū)動(dòng)轉(zhuǎn)速并增大輸入轉(zhuǎn)矩； 1.4 差速器 --- 當(dāng)車(chē)輛轉(zhuǎn)彎行駛時(shí)允許內(nèi)側(cè)驅(qū)動(dòng)輪比外側(cè)驅(qū)動(dòng)輪慢，同時(shí)驅(qū)動(dòng)相等地作用于兩輪。 2 離合器和離合器功用 為了要將發(fā)動(dòng)機(jī)動(dòng)力傳遞到汽車(chē)驅(qū)動(dòng)輪，通常使用磨擦離合器和變速器的組合。前者是為了要逐漸地而且平順地接合并傳遞驅(qū)動(dòng) , 這是必需的，同時(shí)后者按不同比率減少兩輪轉(zhuǎn)速以適合特殊駕駛情況。 離合器運(yùn)行的二個(gè)作用： (1) 它將發(fā)動(dòng)機(jī)與變速器分離使其換檔； (2) 它可以解釋為逐漸的接合驅(qū)動(dòng)車(chē)輪與發(fā)動(dòng)機(jī) ；離合器必須以高速的轉(zhuǎn)動(dòng)來(lái)產(chǎn)生足夠的動(dòng)力，否則會(huì)因負(fù)荷過(guò)大，導(dǎo)致發(fā)動(dòng)機(jī)熄火。 (進(jìn)入靜止?fàn)顟B(tài)) 3 離合器工作原理 為了啟動(dòng)發(fā)動(dòng)機(jī)，駕駛員首先得踩下離合器踏板，使發(fā)動(dòng)機(jī)與變速器分離。 為了使汽車(chē)能夠行駛，駕駛員必須再接合發(fā)動(dòng)機(jī)與變速器。然而，這種接合得是逐漸進(jìn)行的。發(fā)動(dòng)機(jī)在不工作狀態(tài)時(shí)只能產(chǎn)生極小的動(dòng)力。如果二個(gè)部份連接太快，發(fā)動(dòng)機(jī)將會(huì)熄火。同時(shí)負(fù)荷必須被逐漸地加載才可以平順地駕駛汽車(chē)。 駕駛員踩下離合器踏板并掛檔變速器。在駕駛員松開(kāi)離合器踏板之后，離合器成為一個(gè)結(jié)合裝置，將所有的發(fā)動(dòng)機(jī)力量傳遞到變速器，而不會(huì)打滑。 離合器機(jī)構(gòu)包括三個(gè)基本的部份：主動(dòng)部分，從動(dòng)部分，操縱機(jī)構(gòu)。 3.1 主動(dòng)部分 主動(dòng)部分分為兩個(gè)部份: 飛輪和壓力盤(pán)。飛輪直接地被閂在發(fā)動(dòng)機(jī)的傳動(dòng)軸上并且隨之一起轉(zhuǎn)動(dòng)。壓力盤(pán)被閂在飛輪端面上與飛輪一起轉(zhuǎn)動(dòng)。 3.2 從動(dòng)部分 從動(dòng)部分，或離合器盤(pán)，位于飛輪和壓力盤(pán)之間。離合器盤(pán)上有一個(gè)花鍵轂用來(lái)扣在變速器上與從動(dòng)軸連接。離合器盤(pán)的任何轉(zhuǎn)動(dòng)都將帶動(dòng)從動(dòng)軸轉(zhuǎn)動(dòng)，同樣地，從動(dòng)軸的任何運(yùn)動(dòng)都將傳遞到離合器盤(pán)。從動(dòng)盤(pán)在從動(dòng)軸上的前后移動(dòng)、分離嚙合通過(guò)滑動(dòng)花鍵得以實(shí)現(xiàn)。 離合器盤(pán)的內(nèi)部，叫做法蘭盤(pán)轂，有若干的小螺旋彈簧。這些彈簧叫做扭力彈簧。它們讓離合器盤(pán)的中央部份在轂上些微地轉(zhuǎn)動(dòng)，因此彈簧吸收傳動(dòng)軸的扭轉(zhuǎn)振動(dòng)。當(dāng)彈簧完全壓縮時(shí)，離合器壓回到原始位置，直到彈簧松開(kāi)。換句話說(shuō)，離合器吸收這些發(fā)動(dòng)機(jī)振動(dòng)，防止振動(dòng)影響到驅(qū)動(dòng)齒輪 3.3 操縱機(jī)構(gòu) 這些部份是用來(lái)釋放離合器盤(pán)壓力。操縱機(jī)構(gòu)包括有離合器踏板，離合器回位彈簧，離合器聯(lián)動(dòng)裝置，分離叉和分離軸承。離合器聯(lián)動(dòng)裝置包括離合器踏板和機(jī)械的或液壓系統(tǒng)用來(lái)聯(lián)動(dòng)另外的操縱機(jī)構(gòu)。 當(dāng)離合器踏板被踩下的時(shí)候，離合器聯(lián)動(dòng)裝置操縱著分離叉。分離叉，或者叫釋放叉，使分離軸承反向于壓力盤(pán)的分離杠桿移動(dòng)。然后這些杠桿壓縮彈簧將飛輪和離合器盤(pán)緊緊地?fù)伍_(kāi)。此時(shí)，發(fā)動(dòng)機(jī)的轉(zhuǎn)矩還不能夠帶動(dòng)變速器傳動(dòng)軸。變速器檔位可能會(huì)因此加高或者導(dǎo)致車(chē)輛停止。 當(dāng)離合器踏板被松開(kāi)的時(shí)候，壓力盤(pán)強(qiáng)制性的將飛輪與離合器盤(pán)分開(kāi)。在離合器回位彈簧的幫助下踏板逐漸的升起。 4 離合器功用 離合器的主要部份在正常的服務(wù)期間不需要維護(hù)或者是潤(rùn)滑。然而，所有的聯(lián)動(dòng)裝置部份在接點(diǎn)處是需要潤(rùn)滑的。聯(lián)動(dòng)裝置本身需要一定的調(diào)整從而避免發(fā)生與離合器盤(pán)的磨損。 4.1自由行程調(diào)整 你只能在離合器聯(lián)動(dòng)裝置上作一個(gè)調(diào)整——自由行程的調(diào)整。自由行程是存在于離合器盤(pán)分離杠桿和分離軸承中允許的空間里的一段行程。這個(gè)空間是非常重要的，因?yàn)樗艿种聘軛U上的壓力從而組織離合器的嚙合。換句話說(shuō)，分離軸承些微地離開(kāi)壓力盤(pán)杠桿使軸承不產(chǎn)生作用于杠桿的壓力。另一方面，在軸承和杠桿之間又不能有太多的自由行程。如果有太多的間隙，即使當(dāng)駕駛員將離合器踏板踩死，離合器也不能夠完全的起到分離作用。在大部份的情形下，你應(yīng)該在離合器踏板上測(cè)量自由行程，而不是在外殼。 在踏板遇到阻力之前，在剛踩下踏板的時(shí)候，自由行程允許一些移動(dòng)發(fā)生。當(dāng)距離隨著壓力盤(pán)的類型的改變而改變時(shí)，核對(duì)服務(wù)手冊(cè)來(lái)確定自由行程。通常自由行程應(yīng)該是大約 20 到 25 毫米。 在由穿杠和鎖緊螺母組成的離合器聯(lián)動(dòng)裝置的地方自由行程可以被調(diào)整。最接近分離叉的竿是最常用的調(diào)整點(diǎn)。從在車(chē)輛之下尋找竿和鎖緊螺母的位置開(kāi)始。然后決定選一種調(diào)整螺母的方法來(lái)獲得正確的踏板自由行程。如果它仍然有一些移動(dòng)，你能通過(guò)移動(dòng)分離叉來(lái)粗糙估計(jì)一個(gè)自由行程。調(diào)整的最好方式是松開(kāi)鎖緊螺母并且旋轉(zhuǎn)螺帽。然后在踏板上核查自由行程。繼續(xù)這樣調(diào)整下去，直到你獲得正確的自由行程。當(dāng)自由行程調(diào)整到制造廠的規(guī)格時(shí)，勒緊鎖緊螺母。 每六個(gè)月檢查自由行程并且作一些調(diào)整。離合器需要時(shí)常調(diào)整，因?yàn)樽杂尚谐虝?huì)些微地減少比如與離合器盤(pán)的磨損。然而，頻繁的調(diào)整那就意味著離合器機(jī)構(gòu)本身已經(jīng)出現(xiàn)問(wèn)題了。 在分離軸承和壓力盤(pán)分離杠桿之間一定有自由行程。而毛病可能起因于對(duì)離合器的“消遣”。駕駛員將一支腳擱在離合器踏板上使分離軸承與離合器分離杠桿產(chǎn)生摩擦。如此結(jié)果，分離軸承磨損的越來(lái)越快。同時(shí)由于部份裝置沒(méi)有完全嚙合，因此離合器盤(pán)也因?yàn)榛瑒?dòng)而被磨損。 4.2 離合器故障 下列各項(xiàng)是主要的故障: 打滑 ——表面附者不充分造成從動(dòng)片回轉(zhuǎn)的比發(fā)動(dòng)機(jī)飛輪更慢：離合器很熱而且發(fā)出氣味。 自轉(zhuǎn)或咬死——當(dāng)換檔時(shí)轉(zhuǎn)盤(pán)之間分離失敗造成變速器的噪音：其中發(fā)生最多的是在汽車(chē)不動(dòng)的時(shí)候。 顫抖——振動(dòng)發(fā)生在離合器剛接合的時(shí)候，也就是當(dāng)車(chē)輛不動(dòng)的時(shí)候。 猛烈——車(chē)輛的突然啟動(dòng)即使踏板正逐漸松開(kāi)。 5 離合器綜述（補(bǔ)充說(shuō)明） 離合器是一個(gè)用來(lái)連接和斷開(kāi)發(fā)動(dòng)機(jī)驅(qū)動(dòng)力的磨擦裝置。在汽車(chē)的應(yīng)用中，它和發(fā)動(dòng)機(jī)飛輪組合在一起被用于平順地接合和斷開(kāi)發(fā)動(dòng)機(jī)與變速器之間的動(dòng)力傳遞。 因?yàn)閮?nèi)燃機(jī)在低轉(zhuǎn)速時(shí)產(chǎn)生的動(dòng)力或轉(zhuǎn)矩很小，如果要開(kāi)動(dòng)車(chē)輛，就一定得增加轉(zhuǎn)速。然而，如果一臺(tái)快速轉(zhuǎn)動(dòng)的發(fā)動(dòng)機(jī)動(dòng)力突然和車(chē)輛驅(qū)動(dòng)輪連接在一起，那么車(chē)輛肯定會(huì)產(chǎn)生振動(dòng)。 要讓汽車(chē)有一個(gè)合理和舒服的啟動(dòng)，就必須給發(fā)動(dòng)機(jī)逐漸地加載。同時(shí)發(fā)動(dòng)機(jī)轉(zhuǎn)速也要逐漸減慢。車(chē)輛需要能夠?qū)崿F(xiàn)手動(dòng)變速裝置，機(jī)械式離合器就能達(dá)到這個(gè)目的。 離合器的工作過(guò)程就是摩擦的利用過(guò)程。離合器的主要部分是一個(gè)壓盤(pán)和一個(gè)從動(dòng)盤(pán)。壓力盤(pán)與飛輪連接，從動(dòng)盤(pán)裝在變速器的動(dòng)力輸入軸上，壓盤(pán)被緊緊壓在從動(dòng)盤(pán)上。這樣，由于摩擦力的存在，從發(fā)動(dòng)機(jī)發(fā)出的扭矩經(jīng)過(guò)變速器的傳遞而被傳送出來(lái)。通過(guò)兩個(gè)盤(pán)的相互摩擦滑轉(zhuǎn)，直到兩個(gè)盤(pán)之間的壓力扭矩最大時(shí)，動(dòng)力才被平緩地傳遞出來(lái)。 汽車(chē)上裝備有一個(gè)干式緊壓彈簧離合器。如果壓力盤(pán)和從動(dòng)盤(pán)的表面是干的，那么該離合器被稱為干式。相對(duì)的，還有一種離合器稱為油浴式離合器，顧名思義此離合器的壓盤(pán)和從動(dòng)盤(pán)在工作時(shí)是浸在油中。這種離合器之所以叫做緊壓彈簧離合器是因?yàn)閴毫ΡP(pán)和從動(dòng)盤(pán)除了在換擋和剎車(chē)時(shí)是分開(kāi)之外，總是被彈簧緊緊壓在一起。 除了壓盤(pán)和從動(dòng)盤(pán)之外，離合器包括離合器蓋、分離杠桿、分離叉、緊壓彈簧、控制桿系。離合器蓋是一個(gè)鋼制沖件，用螺栓連接在飛輪上。分離杠桿被縛在離合器蓋的螺栓上。分離杠桿的外端連接在壓力盤(pán)上。這樣的構(gòu)造使得壓力盤(pán)既能接近又能遠(yuǎn)離離合器蓋并且始終同飛輪一起轉(zhuǎn)動(dòng)。而沿壓盤(pán)和離合器蓋之間的圓周均勻分布的彈簧夾住壓盤(pán)與飛輪之間的從動(dòng)盤(pán)。 彈簧安裝在離合器蓋和壓力盤(pán)上的凸出物和承座上。為了保護(hù)彈簧免于過(guò)熱受損，在壓力盤(pán)承座上設(shè)有絕熱墊圈。 離合器分離裝置可以是機(jī)械式的也可以是液壓式的。機(jī)械式分離裝置由一個(gè)踏板，回位彈簧、杠桿、竿、分離叉杠桿、分離叉、分離球軸承和一個(gè)離合器分離彈簧組成。當(dāng)離合器踏板被踩下時(shí)，竿和分離叉軸承將扮演起支持作用的分離球軸承的角色。分離軸承壓住分離杠桿的內(nèi)端，于是壓力盤(pán)和從動(dòng)盤(pán)分分開(kāi)，同時(shí)離合器也被分開(kāi)。踏板被松開(kāi)的時(shí)候，由于復(fù)位彈簧的作用分離軸承再次起到支承作用，分離杠桿分離，于是壓盤(pán)被彈簧推向飛輪將從動(dòng)盤(pán)夾住，離合器又再次的接合起來(lái)。 液壓式離合器由離合器踏板、分離彈簧、汽缸、空氣增壓器、管道和軟管、和離合器分離叉杠桿組成。汽缸用一碗狀物體調(diào)整活塞，空氣增壓器用來(lái)在離合器分離時(shí)減少踏板的阻力。增壓器由兩個(gè)有伺服隔膜夾在中間的外殼組成。這個(gè)外殼調(diào)整其中的氣體、液體和伺服柱塞。當(dāng)離合器踏板被踩下時(shí)，活塞的壓力通過(guò)管道傳遞到增壓器的液體和伺服柱塞上。 伺服裝置可以自動(dòng)調(diào)整汽缸里的氣壓以使踩踏板的力度適宜。柱塞和隔膜一同移動(dòng)時(shí)，出口閥門(mén)關(guān)閉，進(jìn)口閥打開(kāi)，空氣進(jìn)入空氣壓縮柱塞內(nèi)被壓縮。由壓縮空氣和壓縮液體產(chǎn)生的力量將分離棒推向分離叉軸承杠桿； 杠桿牽動(dòng)軸和分離叉，于是離合器分離。松開(kāi)踏板，出口閥門(mén)打開(kāi)，入口閥門(mén)關(guān)閉，此時(shí)彈簧使活塞移動(dòng)恢復(fù)了柱塞原始位置，空氣從汽缸中排出。 在美國(guó)和歐洲的汽車(chē)上裝有自動(dòng)離合器。美國(guó)發(fā)動(dòng)機(jī)“E-Stick”的離合器就不需要踩踏板。一個(gè)德國(guó)汽車(chē)制造商設(shè)計(jì)了“Hydrak”的自動(dòng)離合器系統(tǒng)，它由液力偶合器和單片式離合器組成。 在“E-Stick”裝置中， 壓力盤(pán)的杠桿是用來(lái)連接而不是分離離合器盤(pán)的。 同時(shí)，換檔杠桿在檔位中被放置在發(fā)動(dòng)機(jī)工作位置時(shí)，伺服機(jī)構(gòu)在油壓的作用下使離合器分離。 當(dāng)換檔杠桿接入某檔位時(shí)，“Hydrak”也開(kāi)始運(yùn)行。而后增壓機(jī)構(gòu)脫離離合器盤(pán)，液壓離合器被一個(gè)自由飛輪取代。當(dāng)車(chē)輪的轉(zhuǎn)速比發(fā)動(dòng)機(jī)的轉(zhuǎn)速更高的時(shí)候，自由飛輪開(kāi)始工作。一個(gè)特別的機(jī)械裝置根據(jù)后車(chē)橋是否被汽車(chē)動(dòng)力推動(dòng)來(lái)控制離合器的銜合。 有一種不常見(jiàn)的離合器壓板裝置用在最新的克萊斯勒和一些美國(guó)汽車(chē)上， 它叫做半離心式離合器，壓力盤(pán)有六個(gè)圓筒形轉(zhuǎn)子在離心力的作用下向外移動(dòng)，直到它們連到離合器蓋上為止。當(dāng)發(fā)動(dòng)機(jī)轉(zhuǎn)速增加，滾軸自身擠入壓力盤(pán)和離合器蓋之間，因此離合器轉(zhuǎn)動(dòng)越快，加載在壓力盤(pán)和離合器片上的壓力就越大。 參 考 文 獻(xiàn) [1] 帕爾.工業(yè)控制手冊(cè)，帕爾工業(yè)出版公司,1999 ISBN 0-8311-3085-7. [2] 凱爾其·詹姆斯R.“軟件升壓模具設(shè)計(jì)效率”的成型系統(tǒng)，1999，?3:16-23. [3] 李榮顯，陳育民，鄒昶,“開(kāi)發(fā)一個(gè)并行模具設(shè)計(jì)系統(tǒng)：以知識(shí)為基礎(chǔ)的辦法”，計(jì)算 機(jī)集成制造系統(tǒng)，1997，4:287-307. [4] 馬赫.邁克爾.實(shí)時(shí)控制和通訊.第十八屆ESD/重度國(guó)際可編程控制器會(huì)議論文集， 年，P387-399. [5] 埃里克森.可編程邏輯控制器.電氣和電子工程師學(xué)會(huì). 7 中北大學(xué)信息商務(wù)學(xué)院2016屆畢業(yè)設(shè)計(jì)說(shuō)明書(shū) Transmission System 1 Basic Parts of the transmission system The transmission system applies to the components needed to transfer the drive from the engine to the road wheels. The main components and their purposes are 1.1 1.1 Clutch --- to disengage the drive --- to provide a smooth take-up of the drive 1.2 Gearbox --- to increase the torque applied to the driving road wheels --- to enable the engine to operate within a given range of speed irrespective of the vehicle speed --- to give reverse motion of the vehicle --- to provide a neutral position so that the engine can run without moving the vehicle 1.3 Final drive --- to turn the drive through 90° --- to reduce the speed of the drive by a set amount to match the engine to the vehicle 1.4 Differential ---to allow the inner driving road wheel to rotate slower than the outer wheel when the vehicle is cornering, whilst it ensures that a drive is applied equally to both wheels. 2 Clutch and Clutch Service In order to transmit the power of the engine to the road wheels of a car, a friction clutch and a change-speed gearbox are normally employed. The former is necessary in order to enable the drive to be taken up gradually and smoothly, while the latter provides different ratios of speed reduction from the engine to the wheels, to suit the particular conditions of running, A clutch performs two tasks: (1) it disengages the engine from the gearbox to allow for gear changing. (2) it is a means for gradually engaging the engine to the driving wheels, when a vehicle is to be moved from rest the clutch must engage a stationary gearbox shaft with the engine; this must be rotating at a high speed to provide sufficient power or else the load will be too great and the engine will start (come to test). 3 Clutch Action To start the engine, the driver must depress the clutch pedal. This disengages the gearbox from the engine. To move the car, the driver must reengage the gearbox to the engine. However, the engagement of the parts must be gradual. An engine at idle develops little power. If the two parts were connected too quickly, the engine would stall. The load must be applied gradually to operate the car smoothly. A driver depresses the clutch pedal to shift the gears inside the gearbox. After the driver releases the clutch pedal, the clutch must act as solid coupling device. It must transmit all engine power to the gearbox, without slipping. The clutch mechanism include three basic parts: driving member, driven member, operating members. 3.1 The driving member The driving member consists of two parts: the flywheel and the pressure plate. The flywheel is bolted directly to the engine crankshaft and rotates when the crankshaft turns. The pressure plate is bolted to the flywheel. The result is that both flywheel and pressure plate rotate together. 3.2 The driven member The driven member, or clutch disc, is located between the flywheel and pressure plate. The disc has a splined hub that locks to the splined input shaft on the gearbox .Any rotation of the clutch disc turns the input shaft .Likewise, any motion of the input shaft moves the clutch disc. The splines allow the clutch disc to move forward and backward on the shaft as it engages and disengages. The inner part of the clutch disc, called the hub flange, has a number of small coil springs. These springs are called torsional springs. They let the middle part of the clutch disc turn slightly on the hub. Thus, the springs absorb the torsional vibrations of the crankshaft. When the springs have compressed completely, the clutch moves back until the springs relax. In other words, the clutch absorbs these engine vibrations, preventing the vibrations from going through the drive train. 3.3 Operating Members These are the parts that release pressure from the clutch disc. The operating members consist of the clutch pedal, clutch return spring, clutch linkage, clutch fork, and throwout bearing. The clutch linkage includes the clutch pedal and a mechanical or hydraulic system to move the other operating members. When the clutch pedal is depressed, the clutch linkage operates the clutch fork .The clutch fork, or release fork, moves the throwout bearing against the pressure plate release levers. These levers then compress springs that normally hold the clutch disc tightly against the flywheel. At this point, the torque of the engine cannot turn the gearbox input shaft. The gears in the gearbox may be shifted or the vehicle can be brought to a full stop. When the clutch pedal is released, the pressure plate forces the clutch disc against the flywheel. The clutch return spring helps raise the pedal. 4 Clutch Service The major parts of the clutch assembly need no maintenance or lubrication during normal service. However, all linkage parts need lubrication at points of contact. The linkage itself must be adjusted to prevent wear of the clutch disc. 4.1Free-play Adjustment You can make only one adjustment on the clutch linkage —the free-play adjustment. Free play is the allowable space between the throwout bearing and the pressure plate release levers. This space is important because it prevents pressure on the levers that could keep the clutch from engaging fully. In other words, the throwout bearing must be slightly away from the pressure plate levers so that the bearing applies no pressure on the levers. On the other hand, there must not be too much free play between the bearing and the levers. With too much clearance, the clutch cannot fully disengaged when the driver press the clutch pedal to the floor. In most cases, you measure the free play at the clutch pedal, rather than at the bell housing. The free play allows some motion at the beginning of the clutch pedal travel, before the pedal meets resistance. Since the distance varies with the type of pressure plate, check the service manual. Usually, free play should be about 20 to 25mm. Free play can be adjusted at some point where the clutch linkage consists of threaded rods with locknuts. The rod closest to the clutch fork is the most common adjustment point. Begin by locating the rod and locknut beneath the vehicle. Then determine which way to turn the adjustment nuts to get the correct free play at the pedal. You can get a rough estimate of free play by moving the clutch fork to see if it still has some movement. The best way to make the adjustment is to loosen the locknut and move the adjustment nut a few turns. Then check the free play at the pedal. Continue making adjustments until you have the correct free play. When the free-play adjustment meets the manufacturer’s specification, tighten the locknut. Check the free-play adjustment every six months and make any adjustment. Clutches need adjustment that often, since free play decreases slightly as the clutch disc wears. However, the need for frequent adjustments means a problem in the clutch mechanism itself. There must be free play between the throwout bearing and pressure plate release levers. Problems can result from “riding the clutch”. A driver who rests one foot on the clutch pedal causes the throwout bearing to rub against the clutch release levers. As a result, the throwout bearing becomes worn quickly. Also, the clutch disc may wear out due to slippage because the parts are not fully engaged. 4.2 Clutch Faults The following are the main faults: Slip — failure of the surface to grip resulting in the driven plate revolving slower than the engine flywheel : Clutch gets hot and emits an odor. Spin or drag — failure of the plates to separate resulting in noise from the gearbox when selecting a gear: most noticeable when the vehicle is stationary. Judder — a vibration which occurs when the clutch is being engaged , i.e. when the vehicle is stationary. Fierceness — sudden departure of the vehicle even though the pedal is being released gradually. 5 The Clutches（supplementary contract） A clutch is a friction device used to connect and disconnect a driving force from a driven member. In automotive applications, it is used in conjunction with an engine flywheel to provide smooth engagement and disengagement of the engine and manual transmission. Since an internal combustion engine develops little power or torque at low rpm, it must gain speed before it will move the vehicle. However, if a rapidly rotating engine is suddenly connected to the drive line of a stationary vehicle, a violent shock will result. So gradual application of load, along with some slowing of engine speed , is needed to provide reasonable and comfortable starts. In vehicles equipped with a manual transmission, this is accomplished by means of a mechanical clutch. The clutch utilizes friction for its operation. The main parts of the clutch are a pressure plate, and a driven disk. The pressure plate is coupled with the flywheel, while the driven disk is fitted to the disk by the springs so that the torque is transmitted owing to friction forces from the engine to the input shaft of the transmission. Smooth engagement is ensured by slipping of the disk before a full pressure is applied. The automobiles are equipped with a dry spring-loaded clutch. The clutch is termed “dry” because the surfaces of the pressure plate and driven disks are dry in contrast to oil-bath clutches in which the plate and disks operate in a bath of oil. It is called “springloaded” because the pressure plate and the driven disk are always pressed to each other by springs and are released only for a time to shift gears or to brake the automobile. In addition to the plate and disk, the clutch includes a cover, release levers, a release yoke, pressure springs and a control linkage. The clutch cover is a steel stamping bolted to the flywheel. The release levers are secured inside the cover on the supporting bolts. The outer ends of the release levers are articulated to the pressure plate. Such a construction allows the pressure plate to approach the cover or move away from it, all the time rotating with the cover or move away from it, all the time rotating with the flywheel. The springs spaced around the circumference between the pressure plate and the clutch cover clamp the driven disk between the pressure plate and the flywheel. The springs are installed with the aid of projections and sockets provided on the cover and pressure plate. The pressure plate sockets have thermal-insulation gaskets for protecting the springs against overheating. The clutch release mechanism can be operated either mechanically or hydraulically. The mechanically-operated release mechanism consists of a pedal, a return spring, a shaft with lever, a rod m release yoke lever, a release yoke, a release ball bearing with support and a clutch release spring. When the clutch pedal is depressed, the rod and shaft with yoke shift the release bearing and support assembly. The release bearing presses the inner ends of the release levers, the pressure plate is moved away from the driven disk and the clutch is disengaged. To engage the clutch , the pedal is released, the release bearing and support assembly is shifted back by the return spring thus releasing the release levers so that the pressure plate is forced by its springs towards the flywheel to clamp the driven disk and engage the clutch. The clutch hydraulically-operated release mechanism consists of a clutch pedal , clutch release spring , a main cylinder , a pneumatic booster, pipelines and hoses and a lever of the clutch release yoke shaft. Time main cylinder accommodates a piston with a cup. The pneumatic booster serves to decrease the pedal force required disengage the clutch. The booster includes two housings with the servo diaphragm clamped in between. The housing accommodates pneumatic, hydraulic and servo plungers. When the clutch pedal is pushed, the fluid pressure from the main cylinder is transmitted through the pipelines and hoses to the hydraulic and servo plungers of the pneumatic booster. The servo arrangement is intended for automatic change of the air pressure in the pneumatic cylinder proportionally to the force applied to the pedal. The plunger moves with the diaphragm, the outlet valve closes and the inlet valve opens thus admitting the compressed air to the pneumatic plunger piston. The forces created by the pneumatic and hydraulic plungers are added together and are applied through the push rod to the release yoke shaft lever; the lever turns the shaft and the release yoke, thus disengaging the clutch. After the clutch pedal is released, the outlet valve opens and the air from the cylinder is let out to the atmosphere. Automatic clutches were used in certain U.S. and European cars. American Motors’ “E-Stick” clutch eliminated the need for physical operation of the clutch system called “Hydrak”, which consisted of a fluid flywheel connected to a single, dry disk clutch. In the “E-Stick” set up, the pressure plate levers “engage” the clutch disk rather than “release” them. Also, the clutch remains disengaged until a servo unit is applied by oil pressure when the shift lever is placed “in gear” with the engine running. The “Hydrak” unit also begins operation when the lever is “in gear”. This activates a booster unit, which disengages the clutch disk. The hydraulic clutch parts are bridged over by a free-wheel unit, which goes into action when the speed of the rear wheel is higher than the speed of the engine. A special device controls engagement of the mechanical clutch, depending on whether the rear axle is in traction or is pushed by car momentum. A more-or-les unusual clutch pressure plate set-up is used on late model Chrysler and American Motors cars. Called a semi-centrifugal clutch, the pressure plate has six cylindrical rollers which move outward under centrifugal force until they contact the cover. As engine speed increases, the rollers wedge themselves between the pressure plate and cover so that the faster the clutch rotates, the greater the pressure exerted on the pressure plate and disk. Notes [1] E. A. Parr, Industrial Control Handbook, Industrial Press Inc. 1999 ISBN 0-8311-3085-7. [2] Koelsch,?James?R.,?1999,?“Software?boosts?mold?design?efficiency“?Molding?Systems,v57, ? n?3,p?16-23. [3] Lee,?Rong-Shean,?Chen,?Yuh-Min,?Lee,?Chang-Zou,1997?“Development?of?a?concurrent? molddesign?system:?A?knowledge-based?approach”,?Computer?Integrated?Manufacturing Systems,?v 10,n?4,?p?287-307 [4] Maher, Michael J. Real-Time Control and Communications. 18th Annual ESD/SMI International Programmable Controllers Conference Proceedings,1989, p.431-436. [5] Erickson, Kelvin T. (1996). “Programmable Logic Controllers”. Institute of Electrical and Electronics Engineers. VIII