2942 減速箱體機械加工工藝及夾具設(shè)計

2942 減速箱體機械加工工藝及夾具設(shè)計,減速,箱體,機械,加工,工藝,夾具,設(shè)計 XXXXXXXX 學(xué)院本科畢業(yè)設(shè)計（論文）減速箱體機械加工工藝及夾具設(shè)計學(xué)生姓名： 學(xué)生學(xué)號： XXXXXXXX 院（系）： 機電工程學(xué)院 年級專業(yè)： 機械設(shè)計制造及其自動化 指導(dǎo)教師： XXXXXXXX 高級工程師 六月I摘 要箱體零件是一種典型零件，其加工工藝規(guī)程和工裝設(shè)計具有典型性。該箱體零件結(jié)構(gòu)復(fù)雜，零件毛坯采用鑄造成形。在加工過程中，采用先面后孔的加工路線，以保證工件的定位基準(zhǔn)統(tǒng)一、準(zhǔn)確。為了消除切削力、夾緊力、切削熱和因粗加工所造成的內(nèi)應(yīng)力對加工精度的影響，整個工藝過程分為粗、精兩個階段。通過被加工零件的分析完成了機械加工工藝的設(shè)計及各加工工序機動時間的計算。根據(jù)箱體零件的結(jié)構(gòu)及其功能，運用定位夾緊的知識完成了夾具設(shè)計。關(guān)鍵詞 箱體，工藝，夾具IIABSTRACTThis box machine element is typical, the manufacturing process and tooling design of it is typical.The structure of this box machine element is complicated, the machine elements blank adopt casting shape. In the process of manufacture, in order to ensure th -e location datum accurate and unity, I adopt the manufacturing line from face to hole.In order to clear away the influence for machining accurate of internal stress, cutting force, clamping force, heat in cutting from coarse manufacturing, the whole manufacturing pro -cess is made of coarse and accurate manufacturing. Parts were processed through the a -nalysis of the complete machining process design and the manufacturing processes for mobile time calculations. According to the box components and the function and structu -re, the use of the knowledge positioning clamp completed the fixture design.Key words Box machine，Processing，JigIII目 錄摘 要 .IABSTRACT .II1 緒論 .11.1 課題背景 .11.2 制訂工藝規(guī)程的意義與作用及其基本要求 .11.3 夾具的設(shè)計 .12 零件的分析 .22.1 箱體零件的功用和結(jié)構(gòu)特點 .22.2 箱體零件圖樣分析 .22.3 箱體零件工藝分析 .32.4 箱體零件的主要技術(shù)要求 .42.5 主要設(shè)計內(nèi)容 .53 工藝規(guī)程設(shè)計 .73.1 箱體的材料及毛坯 .73.2 減速箱箱體加工的主要問題和加工工藝過程設(shè)計所應(yīng)采取的相應(yīng)措施 .83.3 減速箱體加工定位基準(zhǔn)的選擇 .83.4 制定箱體的工藝路線 .93.5 機械加工余量、工序尺寸及毛坯尺寸的確定 .133.6 確定切削用量及基本工時（機動時間） .153.7 時間定額計算及生產(chǎn)安排 .294 夾具設(shè)計 .364.1 鏜床夾具設(shè)計 .364.1.1 工件加工工藝分析 .364.1.2 定位方案及定位元件設(shè)計 .364.1.3 夾緊方案及夾緊元件設(shè)計 .364.1.4 鏜桿的直徑與長度 .374.1.5 夾具體的設(shè)計 .374.1.6 鏜套的設(shè)計 .374.1.7 切削力及夾緊力計算 .394.1.8 夾具精度分析計算 .41IV4.1.9 鏜孔夾具的裝配說明 .424.2 鉆床夾具設(shè)計 .434.2.1 工件結(jié)構(gòu)特點分析 .434.2.2 工件定位方案和定位元件的設(shè)計 .434.2.3 夾緊方案和夾緊元件的設(shè)計 .434.2.4 夾具體的設(shè)計 .444.2.5 鉆模板的設(shè)計 .444.2.6 鉆套的選擇與設(shè)計 .454.2.7 切削力及夾緊計算 .464.2.8 夾具精度分析計算 .474.2.9 鉆床夾具的裝配說明 .49結(jié) 論 .50參 考 文 獻(xiàn) .51致 謝 .52攀枝花學(xué)院本科畢業(yè)設(shè)計（論文） 1 緒論11 緒論1.1 課題背景畢業(yè)設(shè)計（論文）是我們在學(xué)校學(xué)習(xí)的最后一門課程，也是對自己在大學(xué)中所學(xué)知識的一個全面的檢驗。本課題來自于實際的生產(chǎn)中，是一個典型箱體的加工工藝設(shè)計。要求對部分加工工序進(jìn)行夾具設(shè)計。本課題的題目是：減速箱體機加工工藝及夾具設(shè)計。在畢業(yè)設(shè)計中要求我們要運用所學(xué)的知識，勤動腦，培養(yǎng)獨立的思考能力，要有創(chuàng)新的精神。1.2 制訂工藝規(guī)程的意義與作用及其基本要求機械加工工藝過程是機械生產(chǎn)過程的一部分，是直接生產(chǎn)過程。它是用金屬切削刀具或者磨料工具加工零件，使零件達(dá)到要求的形狀、尺寸和表面粗糙度。因此機械制造加工工藝主要是用切削的方法改變毛坯的形狀、尺寸和材料的物理機械性質(zhì)，成為具有所需的一定精度、粗糙度等的零件。對于加工工藝的編制主要是對其加工工序的確定。對機械加工工藝規(guī)程的基本要求可以總結(jié)為質(zhì)量、生產(chǎn)率和經(jīng)濟性三個方面。這三者雖然有時候有矛盾，但是要把它們協(xié)調(diào)處理好，就成為一個整體。在編制工藝規(guī)程的時候要在保證質(zhì)量的前提下，盡可能的降低成本。因此，好的工藝規(guī)程應(yīng)該是質(zhì)量、生產(chǎn)率和經(jīng)濟性的統(tǒng)一表現(xiàn)。1.3 夾具的設(shè)計制造業(yè)中廣泛應(yīng)用的夾具，是產(chǎn)品制造個工藝階段中十分重要的工藝裝備之一，生產(chǎn)中所使用夾具的質(zhì)量、工作效率及夾具的使用的可靠性，都對產(chǎn)品加工質(zhì)量及生產(chǎn)效率有著決定性的影響。機床夾具一般都由定位裝置、夾緊裝置及其它元件組裝在一個基礎(chǔ)元件（夾具體）上而形成的。由于各類機床的加工工藝特點、夾具和機床的連接方式等不盡相同，因此每一類機床夾具在總體結(jié)構(gòu)和所需元等方面都有自己的特點，但設(shè)計的步驟和方法則基本相同。22 零件的分析2.1 箱體零件的功用和結(jié)構(gòu)特點箱體是機器的基礎(chǔ)零件，它將機器和部件中的軸、齒輪等有關(guān)零件連接成一個整體，并保持正確的相互位置，以傳遞轉(zhuǎn)矩或改變轉(zhuǎn)速來完成規(guī)定的運動。因此箱體的加工質(zhì)量直接影響機器的工作精度、使用性能和壽命。箱體的種類很多，其尺寸大小和結(jié)構(gòu)形式隨著機器的結(jié)構(gòu)和箱體在機器中功用的不同有著較大的差異。但從工藝上分析它們?nèi)杂性S多共同之處，其結(jié)構(gòu)特點是：外形基本上是由六個或五個平面組成的封閉式多面體，又分成整體式和組合式兩種。結(jié)構(gòu)形狀比較復(fù)雜。內(nèi)部常為空腔形，某些部位有“隔墻” ，箱體壁薄且厚薄不均。箱壁上通常都布置有平行孔系或垂直孔系。箱體上的加工面，主要是大量的平面，此外還有許多精度要求較高的軸承支承孔和精度要求較低的緊固用孔。2.2 箱體零件圖樣分析箱體零件圖樣如下圖 2.1 所示： 孔軸心線與 孔軸心線對基準(zhǔn)平面 A 的平行度公差為185H52H80.05mm。底面對前面及右面垂直度公差均為 0.05mm.。 孔軸心線對前面的垂直度公差為 0.05mm。0 兩孔軸心線平行度公差為 0.05mm。58 孔與 孔兩垂直孔的孔距 。1H5281640.5m 孔與 孔兩垂直孔的孔距 。923 兩孔的孔距 。010.3m3CD360圖 2.1 箱體零件圖2.3 箱體零件工藝分析此零件為減速箱箱體，其重要加工表面和次要表面如圖 3.1 中 1 個 、85H2 個 、2 個 、C、D 及如圖 3.1 表面 A、B。508H設(shè)計合理的加工方法，工序數(shù)量和順序，應(yīng)考慮以下的關(guān)系：零件成形的內(nèi)在聯(lián)系：本箱體的材料為 HT200，所以采用鑄造。機械加工中的安排原則與零件的材料、種類、結(jié)構(gòu)形狀，尺寸大小，精度高低相關(guān)聯(lián)。從圖紙上可以看出此箱體的主要的加工面有：如圖 3.1 中 1 個 、2 個 、2 個 、C、D 及如圖85H5083.1 表面 A、B。零件加工質(zhì)量的內(nèi)在聯(lián)系在加工階段劃分中，粗、精加工階段順序分開，其目的在于對主要表面能及時發(fā)現(xiàn)毛坯的氣孔、縮孔、疏松等缺陷。避免后續(xù)工序加工的浪費；粗、精加工由于其加工目的不同，切削用量選取的原則各異，其切削力、切削熱和切削功率也不同。對加工中的主要表面和次要表面為保證主要表面的加工精度和表面粗糙度不受加工中的影響，也應(yīng)劃分加工階段和工序。此箱體的三大部分應(yīng)先加工結(jié)4合面，經(jīng)過裝配，然后加工重要的孔。如圖 3.1 先粗加工減速箱蓋的表面 B，在以此表面為粗基準(zhǔn)來加工減速箱蓋的表面 A。在減速箱座中，先加工 并以185H此為基準(zhǔn)來加工減速箱座的表面 D、C 及其它孔。零件加工成本的內(nèi)在聯(lián)系：機械加工工藝過程中的設(shè)計應(yīng)該考慮工廠的優(yōu)勢。盡量做到：機械加工工藝過程投入最小，物力消耗最低。零件加工生產(chǎn)率的內(nèi)在聯(lián)系機械加工工藝過程設(shè)計中采用工序集中還是工序分散原則；各工序的工時定額是否符合生產(chǎn)節(jié)拍，是否合理的采用了高生產(chǎn)率的工藝方法等。綜上所述主要保證以下精度：在加工前，安排劃線工藝是為了保證工件壁厚均勻，并及時發(fā)現(xiàn)鑄件的缺陷減少廢品。 與 孔兩垂直孔的孔距 ，可采用裝心軸的方法180H5281640.5m檢測。 孔與 孔兩垂直孔的孔距 ，可采用裝心軸的方法92.3檢測。 兩孔的孔距 ?？刹捎醚b心軸的方法檢測。508105.3 孔軸心線與 孔軸心線的平行度 0.05mm,可采用一次裝夾來保1H2H8證。C 面與 A、D 面的垂直度 0.05mm 可由專用夾具或裝夾中機床的精度保證。 孔軸線與 A 面的垂直度 0.05mm 可由專用夾具或裝夾中機床的精度508保證。 兩孔軸線的平行度可采用采用一次裝夾來保證。H2.4 箱體零件的主要技術(shù)要求箱體類零件的精度要求較高，從零件圖可歸納以下五項精度要求?？讖骄瓤讖降某叽缯`差和幾何形狀誤差會使軸承與孔配合不良。裝軸承的孔不圓，也使軸承外環(huán)變形而引起主軸的徑向跳動。主要孔的尺寸精度約為 IT8 級，可由鏜保證。孔和平面的位置精度一般都要規(guī)定主要孔和主軸箱安裝基面的平行度要求，他們決定了主軸與床身導(dǎo)軌的相互位置關(guān)系。這項精度是在總裝過程中通過刮研達(dá)到的。為減少刮研工作量，一般都要規(guī)定主軸軸線對安裝基面的平行度公差。在垂直和水平兩個方5向上只允許主軸前端向上和向前偏。主要平面的精度裝配基面的平面度誤差影響主軸箱與床身連接時的接觸剛度。若在加工過程中作為定位基準(zhǔn)時，還會影響軸孔的加工精度。因此規(guī)定底面和導(dǎo)向面必須平直和相互垂直。其平面度、垂直度公差等級為 5 級。表面粗糙度重要孔和主要表面的表面粗糙度會影響連接面的配合性質(zhì)或接觸剛度，其具體要求一般用 Ra 值來評價。主要孔為 Ra3.2m，其它各縱向孔為 Ra6.3m，裝配基準(zhǔn)面和定位基準(zhǔn)面為 Ra6.3m，其它平面為 Ra12.5m。毛坯鑄造時，應(yīng)防止砂眼和氣孔的產(chǎn)生。為了減少毛坯制造時產(chǎn)生殘余應(yīng)力，應(yīng)使箱體壁厚盡量均勻，箱體鑄造后應(yīng)安排退火或時效處理工序。2.5 主要設(shè)計內(nèi)容本課題的基本內(nèi)容是減速箱體的加工工藝過程與夾具設(shè)計，要研究的主要內(nèi)容有：分析零件圖在設(shè)計開始時，我們應(yīng)認(rèn)真分析零件圖，了解其箱體零件的結(jié)構(gòu)特點和相關(guān)的技術(shù)要求，對箱體零件的每一個細(xì)節(jié)都應(yīng)仔細(xì)分析，如箱體加工表面的平行度、粗糙度、垂直度，特別是要注意箱體零件的各孔系自身的精度（同軸度、圓度、粗糙度等）和它們的相互位置精度（軸線之間的平行度、垂直度以及軸線與平面之間的平行度、垂直度等要求） ，箱體零件的尺寸是整個零件加工的關(guān)鍵，必須弄清箱體零件的每一個尺寸。我們采用 AutoCAD 軟件繪制零件圖，一方面增加對零件的了解認(rèn)識，另一方面增加我們對 CAD 軟件的熟悉。工藝分析箱體零件的工藝分析是整個設(shè)計的重點內(nèi)容，在設(shè)計過程中，我們必須根據(jù)批量等嚴(yán)格地選擇毛坯、擬定工藝路線（注意：基準(zhǔn)選擇、定位、夾緊等問題） 、確定加工余量、計算工藝尺寸、計算工時定額和每一步的工時以及分析定位誤差，為了與實際加工相吻合，我們還必須對加工設(shè)備、切削用量、加工方法等進(jìn)行選擇和設(shè)計，這個階段內(nèi)容較多，涉及的范圍也較廣。為了設(shè)計的參數(shù)合理，我們必須廣泛的查閱相關(guān)的書籍，達(dá)到設(shè)計的合理性和實用性。設(shè)計兩套專用夾具在設(shè)計夾具的過程中，主要要考慮的問題有：基準(zhǔn)選擇：在選擇基準(zhǔn)的時候，要注意區(qū)分粗基準(zhǔn)與精基準(zhǔn)以及要了解基準(zhǔn)的選擇原則，同時要知道基準(zhǔn)的選擇既要滿足選擇原則，同時還要方便定位和6夾緊，以免引起不必要的加工誤差，在基準(zhǔn)選擇完之后就要考慮用什么元件進(jìn)行定位。限制的自由度：在裝夾的過程中，要注意自由度的限制，必須做到準(zhǔn)確的定位，不能出現(xiàn)欠定位或過定位。夾緊機構(gòu)：設(shè)計夾緊機構(gòu)時必須計算分析夾緊力和切削力，不能出現(xiàn)夾緊力過小而使工件在切削的過程中出現(xiàn)松動而影響精度，也不能出現(xiàn)因夾緊力過大而使工件變形影響工件質(zhì)量。同時，還要根據(jù)零件生產(chǎn)批量和生產(chǎn)率的考慮來選擇夾緊方式（手動、氣動或液壓夾緊） 。夾具的用途：為了工件定位準(zhǔn)確和夾緊的快速，提高效率和降低工人的勞動強度，提高箱體零件加工精度和安裝找正方便，我們要采用專用的銑床夾具和鏜床夾具。同時，因為銑床夾具有 T 形槽、鏜床夾具有鏜模等特殊結(jié)構(gòu)，因此還要考慮夾具與機床的匹配，即機床的工作臺尺寸和結(jié)構(gòu)能否滿足夾具的安裝。在夾具設(shè)計過程中，我們統(tǒng)一采用以底面為主要定位面來進(jìn)行加工，因為我們未專門學(xué)習(xí)過夾具的設(shè)計和計算，所以工件量大大地增加了，只有通過在實習(xí)過程中對夾具的感性認(rèn)識和夾具設(shè)計參考書以及夾具圖冊來進(jìn)行設(shè)計和計算，所以夾具的設(shè)計是整個設(shè)計的重點，也是一個難點。夾具的設(shè)計必須要保證夾具的準(zhǔn)確定位和機構(gòu)合理，考慮夾具的定位誤差和安裝誤差。我將通過對工件與夾具的認(rèn)真分析，結(jié)合一些夾具的具體設(shè)計事例，查閱相關(guān)的夾具設(shè)計資料，聯(lián)系在工廠看到的一些箱體零件加工的夾具來解決這些問題。73 工藝規(guī)程設(shè)計3.1 箱體的材料及毛坯箱體材料一般選用 HT200HT400 的各種牌號的灰鑄鐵，最常用的為 HT200，這是因為灰鑄鐵不僅成本低，而且具有較高的耐磨性、可鑄性、可切削性和阻尼特性。在單件生產(chǎn)或某些簡易機床的箱體，為了縮短生產(chǎn)周期和降低成本，可采用鋼材焊接結(jié)構(gòu)。此外，精度要求較高的坐標(biāo)鏜床主軸箱可選用耐磨鑄鐵，負(fù)荷大的主軸箱也可采用鑄鋼件。毛坯的加工余量與生產(chǎn)批量、毛坯尺寸、結(jié)構(gòu)、精度和鑄造方法等因素有關(guān)，有關(guān)數(shù)據(jù)可查有關(guān)資料及數(shù)據(jù)具體情況決定。如級精度灰鑄鐵件，在大批大量生產(chǎn)時，平面的總加工余量為 6 10mm，孔的半徑余量為 7 12mm；單件小批量生:產(chǎn)時，平面為 712mm，孔半徑余量為 8 14mm；成批生產(chǎn)時小于 30mm 的孔和單件小批生產(chǎn)小于 50mm 的孔不鑄出。毛坯的種類常用毛坯種類有：鑄件、鍛件、焊件、沖壓件。各種型材和工程塑料件等。在確定毛坯時，一般要綜合考慮以下幾個因素：a 依據(jù)零件的材料及機械性能要求確定毛坯。對于本箱體材料選為鑄鐵，采用鑄造毛坯。b 依據(jù)零件的結(jié)構(gòu)形狀和外形尺寸確定毛坯，對于結(jié)構(gòu)比較復(fù)雜的零件采用鑄件比鍛件合理；c 依據(jù)生產(chǎn)類型確定毛坯。大批大量生產(chǎn)中，應(yīng)選用制造精度與生產(chǎn)率都比較高的毛坯制造方法。例如模鍛、壓力鑄造等。單件小批生產(chǎn)則采用設(shè)備簡單甚至用手工的毛坯制造方法，例如手工木模砂型鑄造。d 確定毛坯時既要考慮毛坯車間現(xiàn)有生產(chǎn)能力又要充分注意采用新工藝、新技術(shù)、新材料的可能性。本箱體年生產(chǎn)綱領(lǐng)為 2 萬件，屬于大批量生產(chǎn)，材料為 HT200 用鑄造成型。毛坯的形狀及尺寸確定毛坯的尺寸等于零件的尺寸加上或減去加工余量。毛坯的形狀盡可能與零件相適應(yīng)。在確定毛坯的形狀時，為了方便加工，有時還要考慮下列問題：a 為了裝夾穩(wěn)定、加工方便，本零件的鏜削加工可以考慮用專用夾緊。b 為了提高機械加工的生產(chǎn)率，本零件可采用流水線和專用機床進(jìn)行生產(chǎn)。在確定毛坯時，要考慮經(jīng)濟性。雖然毛坯的形狀尺寸與零件接近，可以減少加工余量，提高材料的利用率，降低加工成本，但這樣可能導(dǎo)致毛坯制造困難，8需要采用昂貴的毛坯制造設(shè)備，增加毛坯的制造成本。因此，毛坯的種類形狀及尺寸的確定一定要考慮零件成本的問題且要保證零件的使用性能。在毛坯的種類形狀及尺寸確定后，必要時可據(jù)此繪出毛坯圖。由于本箱體是大量生產(chǎn)，所以應(yīng)該以考慮提高生產(chǎn)效率為先，其次是對節(jié)約成本的考慮。對于零件上的小孔由于鑄造困難，不宜鑄造出，所以在鑄造時只對尺寸較大的孔進(jìn)行鑄造。毛坯的熱處理經(jīng)驗證明，HT200 鑄造性能良好，焊接性能尚好，可切削性好，用于機架，連桿，箱體等。毛坯的熱處理的主要目的是消除因鑄造引起的內(nèi)應(yīng)力。毛坯鑄造時，不允許有沙眼、氣孔、縮孔、非金屬夾雜物等影響機械性能的缺陷。特別是主要加工面要求更高。毛坯還應(yīng)該達(dá)到規(guī)定的化學(xué)成分和機械性能要求。3.2 減速箱箱體加工的主要問題和加工工藝過程設(shè)計所應(yīng)采取的相應(yīng)措施箱體類零件的主要加工部分是平面和孔系。一般來說，保證平面的加工精度要求比保證孔的加工精度要求容易，因此對于箱體來說：加工過程中的主要問題是保證孔的尺寸精度以及位置精度，處理好孔和平面之間的相互關(guān)系?？缀推矫娴募庸ろ樞蛳潴w類零件的加工應(yīng)遵循先面后孔的原則，即先加工箱體上的基準(zhǔn)平面，再以基準(zhǔn)平面定位加工其他平面，然后再加工孔系。因為面的面積較大，用面定位可以確保定位可靠，夾緊牢固，因而容易保證孔的加工精度。其次先加工表面可以切去鑄件表面的凹凸不平，為提高孔的加工精度創(chuàng)造條件，便于對刀具的調(diào)整，也有利于保護(hù)刀具?？紫导庸し桨傅倪x擇箱體孔系的加工方案，應(yīng)該選擇能夠滿足孔系加工精度要求的加工方法及設(shè)備。除了從加工精度和加工效率兩方面考慮以外，也要適當(dāng)考慮經(jīng)濟因素，在滿足精度要求以及生產(chǎn)率的條件下，應(yīng)該選用價格比較低的機床。3.3 減速箱體加工定位基準(zhǔn)的選擇粗基準(zhǔn)的選擇粗基準(zhǔn)選擇應(yīng)當(dāng)滿足以下要求：保證各主要孔的加工余量均勻；保證端面的加工余量均勻。9精基準(zhǔn)的選擇從保證箱體面與孔，孔與孔，面與面之間的位置關(guān)系考慮，精基準(zhǔn)面的選擇應(yīng)能保證箱體在整個加工過程中基本上都能用統(tǒng)一基準(zhǔn)定位。綜上在本零件圖中先以其 B 面為粗基準(zhǔn)來加工表面 A，然后再以表面 A 為精基準(zhǔn)來加工其上面的孔。再以 A、B 面定位加工 孔。以 A 面和 孔185H185H定位加工其它表面和孔。其粗、精基準(zhǔn)如圖 3.1 所示。AB159圖 3.1 箱體零件圖粗、精基準(zhǔn)3.4 制定箱體的工藝路線對于大量生產(chǎn)的零件，一般是首先加工出統(tǒng)一的定位基準(zhǔn)。粗、精基準(zhǔn)的選擇前面已做介紹。后續(xù)工序安排應(yīng)當(dāng)遵循先粗后精、粗精分開和先面后孔的原則。先粗加工平面，再粗加工孔系。按上述原則亦應(yīng)先精加工平面再加工孔系。各螺紋孔的攻絲，由于切削力較小，可以安排在粗、精加工階段中分散進(jìn)行。10根據(jù)以上分析過程，現(xiàn)將箱體加工工藝路線確定如下 2 種方案：方案一：工序號 工序名稱1 鑄造2 清砂3 熱處理（人工時效處理）4 涂紅色防銹底漆5 劃線（劃 、 、 孔軸心線，A、B 平面加185H2850H工線）6 粗銑箱體表面 A7 精銑箱體表面 A8 粗銑箱體表面 B9 粗銑箱體表面 D10 粗銑箱體表面 C11 精銑箱體表面 B12 精銑箱體表面 D13 精銑箱體表面 C14 粗鏜 185H15 粗鏜 孔、 孔02816 粗鏜 孔17 精鏜18 精鏜 孔、 孔519 精鏜 孔2H820 劃線（劃兩處 8M6、4M6、6M6，一處 6M12、4M8配作孔加工線）21 鉆一處 6M12、6M6、4M8 孔，兩處 8M6 孔工步：鉆 6-M12 深 12 底孔鉆 4-M8-7H 底孔6M6 深 12 底孔22 鉆兩處 8M6 孔23 攻絲工步：攻絲（6-M12 深 12）11攻絲（4-M8-7H）攻絲（6-M6 深 12）24 攻絲25 鉆一處 6M6，兩處 4M6（C 向）工步：鉆 6-M6 底孔鉆 4-M6 底孔26 攻絲工步：攻絲（6-M6）攻絲（4-M6）27 鉆（修毛刺）28 煤油滲漏實驗29 按圖樣檢查工件各部尺寸及精度30 清洗、終檢以及入庫方案二：工序號 工序名稱1 鑄造2 清砂3 熱處理（人工時效處理）4 涂紅色防銹底漆5 劃線（劃 、 、 孔軸心線，A、B 平面加185H2850H工線）6 粗、精銑箱體表面 A工步：粗銑精銑7 粗銑箱體表面 B8 粗銑箱體表面 D9 粗銑箱體表面 C10 粗鏜 185H11 粗鏜 、 孔2012 粗鏜 孔13 精銑箱體表面 B1214 精銑箱體表面 D15 精銑箱體表面 C16 精鏜 185H17 精鏜 、 孔0218 精鏜 孔19 劃線（劃兩處 8M6、4M6、6M6，一處 6M12、4M8配作孔加工線）20 鉆一處 6M12、6M6、4M8 孔，兩處 8M6 孔工步：鉆 6-M12 深 12 底孔鉆 4-M8-7H 底孔6M6 深 12 底孔21 并攻絲攻絲（6-M12 深 12）攻絲（4-M8-7H）攻絲（6M6 深 12）22 鉆兩處 8M6 孔底孔23 攻絲（8M6 深 12）24 鉆一處 6M6，兩處 4M6（C 向）工步：鉆 6-M6 底孔鉆 4-M6 底孔25 并攻絲攻絲（6-M6）攻絲（4-M6）26 鉆（修毛刺）27 煤油滲漏實驗28 按圖樣檢查工件各部尺寸及精度29 清洗、終檢以及入庫兩種方案的比較與分析：由以上兩種方案的分析與比較可得：方案一的工序比較集中。由于在本設(shè)計中采用鑄造毛坯，大批量生產(chǎn)，工序集中有利于保證各加工面間的相互位置精度要求，有利于采用高生產(chǎn)率機床，節(jié)省裝夾工件的時間，減少工件的半動次數(shù)。因此采用工序集中的方案二。133.5 機械加工余量、工序尺寸及毛坯尺寸的確定根據(jù)生產(chǎn)綱領(lǐng)和零件結(jié)構(gòu)選擇毛坯：零件毛坯材料選擇為 HT200，硬度 HB187225，抗拉強度 320 ，生MPab/產(chǎn)類型為大量生產(chǎn)，采用鑄造毛坯。表面的加工余量：表面 A：粗銑表面 A：參照文獻(xiàn)3表 6-28，其余量值規(guī)定為 3.0mm精銑表面 A：參照文獻(xiàn)3表 6-30，其余量值規(guī)定為 1.0mm鑄造毛坯的基本尺寸為 參照文獻(xiàn)4表 2.3-11,鑄件49321507m尺寸公差等級選用 IT12，再查表 2.3-9 可得鑄件尺寸公差為 0.63。零件基本尺寸為： 毛坯的名義尺寸為： 毛坯最小尺寸為： 507-.63.7毛坯最大尺寸為： m銑削后的尺寸應(yīng)與圖紙要求尺寸相同： 490.63表面 B：粗銑表面 B：參照文獻(xiàn)3表 6-28，其余量值規(guī)定為 3.0mm精銑表面 B：參照文獻(xiàn)3表 6-30，其余量值規(guī)定為 1.0mm鑄造毛坯的基本尺寸為 參照文獻(xiàn)4表 2.3-11,鑄49321507m件尺寸公差等級選用 IT12，再查表 2.3-9 可得鑄件尺寸公差為 0.63m。零件基本尺寸為： m毛坯的名義尺寸為： 毛坯最小尺寸為： 507-.63.7毛坯最大尺寸為： 銑削后的尺寸應(yīng)與圖紙要求尺寸相同： 490.63m表面 C：粗銑表面 C：參照文獻(xiàn)3表 6-28，其余量值規(guī)定為 2.0mm精銑表面 C：參照文獻(xiàn)3表 6-30，其余量值規(guī)定為 1.0mm鑄造毛坯的基本尺寸為 參照文獻(xiàn)4表 2.3-11,鑄件21521尺寸公差等級選用 IT12，再查表 2.3-9 可得鑄件尺寸公差為 0.46m。零件基本尺寸為： m毛坯的名義尺寸為： 毛坯最小尺寸為： 21-0.46.5毛坯最大尺寸為： 214銑削后的尺寸應(yīng)與圖紙要求尺寸相同： 2150.46m表面 D：粗銑表面 D：參照文獻(xiàn)3表 6-28，其余量值規(guī)定為 2.0mm精銑表面 D：參照文獻(xiàn)3表 6-30，其余量值規(guī)定為 1.0mm鑄造毛坯的基本尺寸為 參照文獻(xiàn)4表 2.3-11,鑄件235124尺寸公差等級選用 IT12，再查表 2.3-9 可得鑄件尺寸公差為 。0.46m零件基本尺寸為： m毛坯的名義尺寸為： 毛坯最小尺寸為： 241-0.6.54毛坯最大尺寸為： 銑削后的尺寸應(yīng)與圖紙要求尺寸相同： 230.6m鏜孔的加工余量：的加工余量：185H粗鏜表面：參照文獻(xiàn)3表 6-22，其余量值規(guī)定為 0.3mm精鏜表面：參照文獻(xiàn)3表 6-22，其余量值規(guī)定為 0.1mm鑄造件的機械加工余量參照文獻(xiàn)4表 2.35，其單邊余量規(guī)定為：1.5mm。鑄件尺寸公差等級選用 IT8，再查表 2.3-9 可得鑄件尺寸公差為 2.5mm。零件基本尺寸為： 185mm毛坯的名義尺寸為： 185.20.3.128.m毛坯最小尺寸為： -75毛坯最大尺寸為： .9.精鏜后的尺寸應(yīng)與圖紙要求尺寸相同： 0.72的加工余量：2508H粗鏜表面：參照文獻(xiàn)3表 6-22，其余量值規(guī)定為 0.3mm精鏜表面：參照文獻(xiàn)3表 6-22，其余量值規(guī)定為 0.1mm鑄造件的機械加工余量參照文獻(xiàn)4表 2.35，其單邊余量規(guī)定為：1.5mm。鑄件尺寸公差等級選用 IT9，再查表 2.3-9 可得鑄件尺寸公差為 2.0mm。零件基本尺寸為： 50mm毛坯的名義尺寸為： 501.2.30.123.8m毛坯最小尺寸為： 38-毛坯最大尺寸為： .4.精鏜后的尺寸應(yīng)與圖紙要求尺寸相同： 0.395的加工余量：528H粗鏜表面：參照文獻(xiàn)3表 6-22，其余量值規(guī)定為 0.3mm15精鏜表面：參照文獻(xiàn)3表 6-22，其余量值規(guī)定為 0.1mm鑄造件的機械加工余量參照文獻(xiàn)4表 2.35，其單邊余量規(guī)定為：1.5mm。鑄件尺寸公差等級選用 IT9，再查表 2.3-9 可得鑄件尺寸公差為 2.0mm。零件基本尺寸為： 52mm毛坯的名義尺寸為： 521.0.32.1.8m毛坯最小尺寸為： 8-4毛坯最大尺寸為： .6.精鏜后的尺寸應(yīng)與圖紙要求尺寸相同： 0.465鉆孔的加工余量：6-M127H 加工余量：毛坯為實心。參照文獻(xiàn)3表 6-51，現(xiàn)確定螺孔加工余量為：鉆孔： ,10.2m攻絲： M127H4-M87H 加工余量：毛坯為實心。參照文獻(xiàn)3表 6-51，現(xiàn)確定螺孔加工余量為：鉆孔： ,6.7攻絲： M87H4-M6 深 12 加工余量：毛坯為實心。參照文獻(xiàn)3表 6-51，現(xiàn)確定螺孔加工余量為：鉆孔： ,5m攻絲： M6 深 126-M6 深 12、8-M6 深 12 加工余量與 4-M6 深 12 加工余量相同。3.6 確定切削用量及基本工時（機動時間）粗銑表面 A：所選刀具如表 3.1表 3.1 機床 XE755機床型號工作臺面積 （長X 寬） mm 縱向行程 橫向行程主軸轉(zhuǎn)速r/min工作臺進(jìn)給量XE755 5002000 1400mm 500mm 251250 141250mm/min刀具：硬質(zhì)合金端銑刀（面銑刀） 齒數(shù)mdw4014Z16銑削深度 ：pam3每齒進(jìn)給量 ：參照文獻(xiàn)4表 2.4-73，取f 0.2/famZ銑削速度 ：參照文獻(xiàn)4表 2.4-81，取V186Vs機床主軸轉(zhuǎn)速 ： 式(3.1)n01/Vd01.869.in34nrd取 /minr實際銑削速度 ：V03.1402.9/6dms進(jìn)給量 ： f .140/6.7/ffaZns工作臺每分進(jìn)給量 ：m.280minfV：參照文獻(xiàn)4表 2.4-81,a被切削層長度 ：由毛坯尺寸可知l 9l刀具切入長度 ： 1aD4)31(5.02刀具切出長度 ：取2l走刀次數(shù)為 1機動時間 ： 式(3.2)jt12jmlf1249.94in80jmltf精銑表面 A：此次的機床與刀具與前面相同。銑削深度 ：pa1.0每齒進(jìn)給量 ：參照文獻(xiàn)4表 2.4-73，取f 2.0/famr銑削速度 ：參照文獻(xiàn)4表 2.4-81，取V38Vs根據(jù)式（3.1）機床主軸轉(zhuǎn)速 ： ，取n01.614/in14d120/minr實際銑削速度 ：V03.142.5/60dms進(jìn)給量 ： f .2/ffans17工作臺每分進(jìn)給量 ：mf4/20/minfVs：參照文獻(xiàn)4表 2.4-81,aa被切削層長度 ：由毛坯尺寸可知l 9l刀具切入長度 ： 1D4)31(5.02刀具切出長度 ：取2l走刀次數(shù)為 1根據(jù)式（3.2）機動時間 ： 1jt1292.7min40jmlf粗銑表面 B：此次的機床與刀具與前面相同。由于 B 面 A 面粗糙度、長度相同故其切削用量及基本工時與粗銑表面 A 相同粗銑表面 D：此次的機床與刀具與前面相同。銑削深度 ：pa3.0m每齒進(jìn)給量 ：參照文獻(xiàn)4表 2.4-73，取f 2.0/famr銑削速度 ：參照文獻(xiàn)4表 2.4-81，取V164Vs根據(jù)式（3.1）機床主軸轉(zhuǎn)速 ： ，n0.78.3/in3rd就取 =80/minr1.3/s實際銑削速度 ：V03.1481.67/0dms進(jìn)給量 ： f 28/6.7/ffans工作臺每分進(jìn)給量 ：m /inf ：參照文獻(xiàn)4表 2.4-81,a40被切削層長度 ：由毛坯尺寸可知l 235lm刀具切入長度 ： 10.5(1)8Da刀具切出長度 ：取2l走刀次數(shù)為 1根據(jù)式（3.2）機動時間 ：1jt123521.6min0jmlf粗銑箱體表面 C此次的機床與刀具與前面相同。18銑削深度 ：pa3.0m每齒進(jìn)給量 ：參照文獻(xiàn)4表 2.4-73，取f 2.0/famr銑削速度 ：參照文獻(xiàn)4表 2.4-81，取V164Vs根據(jù)式（3.1）機床主軸轉(zhuǎn)速 ： ，n0.78.3/in3rd就取 80/minr實際銑削速度 ：V03.1481.67/0dms進(jìn)給量 ： f 28/6.7/ffans工作臺每分進(jìn)給量 ：m /inf ：參照文獻(xiàn)4表 2.4-81,a40被切削層長度 ：由毛坯尺寸可知l 215lm刀具切入長度 ： 10.5(3)8Da刀具切出長度 ：取2l走刀次數(shù)為 1根據(jù)式（3.2）機動時間 ： 1jt12521.53min60jmlf精銑箱體表面 B此次的機床與刀具與前面相同。由于 B 面 A 面粗糙度、長度相同故其切削用量及基本工時與精銑表面 A 相同精銑表面 D：此次的機床與刀具與前面相同。銑削深度 ：pa1.0m每齒進(jìn)給量 ：參照文獻(xiàn)4表 2.4-73，取f 0.1/famZ銑削速度 ：參照文獻(xiàn)4表 2.4-81，取V2Vs根據(jù)式（3.1）機床主軸轉(zhuǎn)速 ： ，取n01.605/in34rd10/minr實際銑削速度 ：V03.142.9/60dms進(jìn)給量 ： f ./.3/ffaZn工作臺每分進(jìn)給量 ：m2.14infs19：參照文獻(xiàn)4表 2.4-81,ama240被切削層長度 ：由毛坯尺寸可知l 35l刀具切入長度 ： 10.5(1)2D刀具切出長度 ：取2l走刀次數(shù)為 1根據(jù)式（3.2）機動時間 ： 1jt123581.9min40jmlf精銑表面 C：此次的機床與刀具與前面相同。銑削深度 ：pa1.0每齒進(jìn)給量 ：參照文獻(xiàn)4表 2.4-73，取f 0.1/faZ銑削速度 ：參照文獻(xiàn)4表 2.4-81，取V2Vms根據(jù)式（3.1）機床主軸轉(zhuǎn)速 ： ，取n01.69/in34rd10/minr實際銑削速度 ：V03.142.9/60dms進(jìn)給量 ： f ./.3/ffaZn工作臺每分進(jìn)給量 ：m2.14infs：參照文獻(xiàn)4表 2.4-81,a0被切削層長度 ：由毛坯尺寸可知：當(dāng) 時：l 5lm刀具切入長度 ： 120.5(3)28Da刀具切出長度 ：取2l走刀次數(shù)為 1根據(jù)式（3.2）機動時間 ： 1jt1251.75in40jmlf鏜孔的切削用量與基本工時：參照文獻(xiàn)4表 3.1-40 選擇臥式鏜床 T68，其最大的加工孔徑：240mm。工作臺最大移動距離縱向為 1140mm，橫向為 850mm。主軸轉(zhuǎn)速級數(shù)為 18 級。主軸轉(zhuǎn)速范圍為 20 至 1000（r/min） 。從表 2.4-66 選擇刀具選擇硬質(zhì)合金鏜刀。參照文獻(xiàn)4得鏜孔工時計算公式為： 20= 式(3.3)jtifnlifL21式(3.4)3(1rptgkal52l粗鏜 ：185H查文獻(xiàn)4 表 2.4-66：切削深度 =2.0mm，進(jìn)給量 f=0.32mm/r。查文獻(xiàn)4pa表 3.1-41 轉(zhuǎn)速 n=80r/min，切削速度 ，因此：1856437.18/min00dnV80/minr.3f12.0()(3)445praltgktg24l根據(jù)式（3.3）得： 596.2min80.3jt精鏜 ：185H查文獻(xiàn)4 表 2.4-66：切削深度 =0.1mm，進(jìn)給量 f=0.16mm/r。查文獻(xiàn)4pa表 3.1-41 轉(zhuǎn)速 n=200r/min，切削速度 ，因185206./min0dnV此 20/minr.15f10.1(3)(23).545praltgktg2l根據(jù)式（3.3）得： 59.1min06jt粗鏜 ：821查表 2.4-66：切削深度 =1.8mm，進(jìn)給量 f=0.25mm/r。查表 3.1-41 轉(zhuǎn)速pan=50r/min，切削速度 ，因此：82501.7/min10dnV5/mir.2f11.8(3)(23)54praltgktg2.5l.16min0jt由于是兩個孔所以是 .43.8精鏜 ：82查表 2.4-66：切削深度 =0.1mm，進(jìn)給量 f=0.15mm/r。查表 3.1-41 轉(zhuǎn)速pan=250r/min，切削速度 ，因此：825064.37/min10dnV5/mir.f10.1(23)(23)45praltgktg2l0.8min5.1jt由于是兩個孔所以是 496粗鏜 ：528H查文獻(xiàn)4 表 2.4-66：切削深度 =1.8mm，進(jìn)給量 f=0.25mm/r。查文獻(xiàn)4pa表 3.1-41 轉(zhuǎn)速 n=80r/min，切削速度 ，因此：528013.6/min10dnV80/minr.25f2211.8(23)(23)54praltgktg2.5l0.15.min8jt精鏜 ：58H查文獻(xiàn)4 表 2.4-66：切削深度 =0.1mm，進(jìn)給量 f=0.15mm/r。查文獻(xiàn)4pa表 3.1-41 轉(zhuǎn)速 n=250r/min=4，切削速度 ，5204.82/min10dnV因此： 250/minr.1f10.1(3)(23)45praltgktg2l08.16min5.jt粗鏜 ：508H查文獻(xiàn)4 表 2.4-66：切削深度 =1.8mm，進(jìn)給量 f=0.25mm/r。查文獻(xiàn)4pa表 3.1-41 轉(zhuǎn)速 n=50r/min，切削速度 ，因此：5207.8/min10dnV50/minr.2f11.8(3)(23)54praltgktg2.5l9.87min0jt由于是兩個孔所以是 .316.精鏜 ：508H查文獻(xiàn)4 表 2.4-66：切削深度 =0.1mm，進(jìn)給量 f=0.15mm/r。查文獻(xiàn)4pa23表 3.1-41 轉(zhuǎn)速 n=250r/min，切削速度 ，因50239.5/min1dnV此： 250/minr.1f10.1(3)(23)45praltgktg2l59.7min0.1jt由于是兩個孔所以是 48鉆孔的切削用量與基本工時：參照文獻(xiàn)4表 3.1-30 選擇搖臂鉆床 Z3025 如下表 3.2。表 3.2 Z3025機床型號 最大鉆孔直徑 主軸最大行程 主軸轉(zhuǎn)速范圍 主軸進(jìn)給量范圍Z3025 25mm 250mm 50-2500r/min 0.05-1.6min/r鉆 6-M12-7H 的底孔：刀具：參照文獻(xiàn)4表 4.3-7 直柄麻花鉆（GB1436-85）第一系列其麻花鉆參數(shù)如表 3.3 表 3.3 直柄麻花鉆d 10.2l 133l1 87切削深度 ：pa5.m進(jìn)給量 ：參照文獻(xiàn)4表 2.4-39，取f 0.3/fmr切削速度 ：參照文獻(xiàn)4表 2.4-68，V=V4s根據(jù)式（3.1）機床主軸轉(zhuǎn)速 ： ，n01.608英文原文：SHAFT AND GEAR DESIGNAbstract: The important position of the wheel gear and shaft can t falter in traditional machine and modern machines. The wheel gear and shafts mainly install the direction that delivers the dint at the principal axis box. The passing to process to make them can is divided into many model numbers, useding for many situations respectively. So we must be the multilayers to the understanding of the wheel gear and shaft in many waysKey words : Wheel gear ; ShaftIn the force analysis of spur gears, the forces are assumed to act in a single plane .We shall study gears in which the forces have three dimensions.The reason for this, in the case of helical gears, is that the teeth are not parallel to the axis of rotation. And in the case of bevel gears, the rotational axes are not parallel to each other. There are also other reasons, as we shall learn.Helical gears are used to transmit motion between parallel shafts. The helix angle is the same on each gear, but one gear must have a right-hand helix and the other a left-hand helix. The shape of the tooth is an involute helicoid. If a piece of paper cut in the shape of a parallelogram is wrapped around a cylinder, the angular edge of the paper becomes a helix. If we unwind this paper, each point on the angular edge generates an involute curve. The surface obtained when every point on the edge generates an involute is called an involute helicoid. The initial contact of spur-gear teeth is a line extending all the way across the face of the tooth. The initial contact of helical gear teeth is a point, which changes into a line as the teeth come into more engagement. In spur gears the line of contact is parallel to the axis of the rotation; in helical gears, the line is diagonal across the face of the tooth. It is this gradual of the teeth and the smooth transfer of load from one tooth to another, which give helical gears the ability to transmit heavy loads at high speeds. Helical gears subject the shaft bearings to both radial and thrust loads. When the thrust loads become high or are objectionable for other reasons, it may be desirable to use double helical gears. A double helical gear (herringbone) is equivalent to two helical gears of opposite hand, mounted side byside on the same shaft. They develop opposite thrust reactions and thus cancel out the thrust load. When two or more single helical gears are mounted on the same shaft,the hand of the gears should be selected so as to produce the minimum thrust load Crossed-helical, or spiral, gears are those in which the shaft centerlines are neither parallel nor intersecting. The teeth of crossed-helical fears have point contact with each other, which changes to line contact as the gears wear in. For this reason they will carry out very small loads and are mainly for instrumental applications, and are definitely not recommended for use in the transmission of power There is on difference between a crossed heli cal gear and a helical gear until they are mounted in mesh with each other. They are manufactured in the same way. A pair of meshed crossed helical gears usually have the same hand; that is , a right-hand driver goes with a right-hand driven. In the design of crossed-helical gears, the minimum sliding velocity is obtained when the helix angle are equal. However, when the helix angle are not equal, the gear with the larger helix angle should be used as the driver if both gears have the same handWorm gears are similar to crossed helical gears. The pinion or worm has a small number of teeth, usually one to four, and since they completely wrap around the pitch cylinder they are called threads. Its mating gear is called a worm gear, which is not a true helical gear. A worm and worm gear are used to provide a high angular-velocity reduction between nonintersecting shafts which are usually at right angle. The worm gear is not a helical gear because its face is made concave to fit the curvature of the worm in order to provide line contact instead of point contact. However, a disadvantage of worm gearing is the high sliding velocities across the teeth, the same as with crossed helical gearsWorm gearing are either single or double enveloping. A single-enveloping gearing is one in which the gear wraps around or partially encloses the worm. . A gearing in which each element partially encloses the other is, of course, a double-enveloping worm gearing. The important difference between the two is that area contact exists between the teeth of doubleenveloping gears while only line contact between those of single-enveloping gears. The worm and worm gear of a set have the same hand ofhelix as for crossed helical gears, but the helix angles are usually quite different The helix angle on the worm is generally quite large, and that on the gear very small Because of this, it is usual to specify the lead angle on the worm, which is the complement of the worm helix angle, and the helix angle on the gear; the two angles are equal for a 90-deg. Shaft angleWhen gears are to be used to transmit motion between intersecting shaft, some of bevel gear is required. Although bevel gear are usually made for a shaft angle of 90 deg. They may be produced for almost any shaft angle. The teeth may be cast, milled, or generated. Only the generated teeth may be classed as accurate. In a typical bevel gear mounting, one of the gear is often mounted outboard of the bearing. This means that shaft deflection can be more pronounced and have a greater effect on the contact of teeth. Another difficulty, which occurs in predicting the stress in bevel-gear teeth, is the fact the teeth are tapered.Straight bevel gears are easy to design and simple to manufacture and give very good results in service if they are mounted accurately and positively. As in the case of squr gears, however, they become noisy at higher values of the pitch-line velocity In these cases it is often go od design practice to go to the spiral bevel gear, which is the bevel counterpart of the helical gear. As in the case of helical gears, spiral bevel gears give a much smoother tooth action than straight bevel gears, and hence are useful where high speed are encountered. It is frequently desirable, as in the case of automotive differential applications, to have gearing similar to bevel gears but with the shaft offset. Such gears are called hypoid gears because their pitch surfaces are hyperboloids of revolution The tooth action between such gears is a combination of rolling and sliding alonga straight line and has much in common with that of worm gears A shaft is a rotating or stationary member, usually of circular cross section, having mounted upon it such elementsas gears, pulleys, flywheels, cranks, sprockets, and other power-transmission elements. Shaft may be subjected to bending, tension, compression, or torsional loads, acting singly or in combination with one another. When they are combined, one may expect to find both static and fatigue strength tobe important design considerations, since a single shaft may be subjected to static stresses, completely reversed, and repeated stresses, all acting at the same time The word shaft covers numerous variations, such as axles and spindles. Anaxle is a shaft, wither stationary or rotating, nor subjected to torsion load. A shirt rotating shaft is often called a spindle. When either the lateral or the torsional deflection of a shaft must be held to close limits, the shaft must be sized on the basis of deflection before analyzing the stresses. The reason for this is that, if the shaft is made stiff enough so that the deflection is not too large, it is probable that the resulting stresses will be safe. But by no means should the designer assume that they are safe; it is almost always necessary to calculate them so that he knows they are within acceptable limits Whenever possible, the power-transruission elements, such as gears or pullets, should be located close to the supporting bearings, This reduces the bending moment, and hence the deflection and bending stress.Although the von Mises-Hencky-Goodman method is difficult to use in design of shaft, it probably comes closest to predicting actual failure. Thus it is a good way of checking a shaft that has already been designed or of discovering why a particular shaft has failed in service. Furthermore, there are a considerable number of shaft-design problems in which the dimension are pretty well limited by other considerations, such as rigidity, and it is only necessary for the designer to discover something about the fillet sizes, heat-treatment, and surface finish and whether or not shot peening is necessary in order to achieve the required life and reliabilityBecause of the similarity of their functions, clutches and brakes are treated together. In a simplified dynamic representation of a friction clutch, or brake two in ertias 11 and 12 traveling at the respective angular velocities Wl and W2, one of which may be zero in the case of brake, are to be brought to the same speed by engaging the clutch or brake. Slippage occurs because the two elements are running at different speeds and energy is dissipated during actuation, resulting in a temperature rise. In analyzing the performance of these devices we shall beinterested in the actuating force, the torque transmitted, the energy loss and the temperature rise. The torque transmitted is related to the actuating force, the coefficient of friction, and the geometry of the clutch or brake. This is problem in static, which will have to be studied separately for eath geometric configuration. However, temperature rise is related to energy loss and can be studied without regard to the type of brake or clutch because the geometry of interest is the heat-dissipating surfaces. The various types of clutches and brakes may be classified as fllows1. Rim type with internally expanding shoes2. Rim type with externally contracting shoes3。 Band type4. Disk or axial type5 Cone type6. Miscellaneous typeThe analysis of all type of friction clutches and brakes use the same general procedure. The following step are necessary1. Assume or determine the distribution of pressure on the frictional surfaces2. Find a relation between the maximum pressure and the pressure at any point3. Apply the condition of statical equilibrium to find (a) the actuating force, (b) the torque, and (c) the support reactionsMiscellaneous clutches include several types, such as the positive-contact clutches, overload-release clutches, overrunning clutches, magnetic fluid clutches, and others.A positive-contact clutch consists of a shift lever and two jaws. The greatest differences between the various types of positive clutches are concerned with the design of the jaws. To provide a longer period of time for shift action during engagement, the jaws may be ratchet-shaped, or gear-tooth-shaped. Sometimes a greatmany teeth or jaws are used, and they may be cut either circumferentially, so that they engage by cylindrical mating, or on the faces of the mating elements Although positive clutches are not used to the extent of the frictional-contact type, they do have important applications where synchronous operation is required Devices such as linear drives or motor-operated screw drivers must run to definite limit and then come to a stop. An overload-release type of clutch is required for these applications. These clutches are usually spring-loaded so as to release at a predetermined toque. The clicking sound which is heard when the overload point is reached is considered to be a desirable signal An overrunning clutch or coupling permits the driven member of a machine to freewheel or overrun because the driver is stopped or because another source of power increase the speed of the driven. This type of clutch usually uses rollers or balls mounted between an outer sleeve and an inner member having flats machined around the periphery. Driving action is obtained by wedging the rollers between the sleeve and the flats. The clutch is therefore equivalent to a pawl and ratchet with an infinite number of teeth Magnetic fluid clutch or brake is a relatively new development which has two parallel magnetic plates. Between these plates is a lubricated magnetic powder mixture. An electromagnetic coil is inserted somewhere in the magnetic circuit. By varying the excitation to this coil, the shearing strength of the magnetic fluid mixture may be accurately controlled. Thus any condition from a full slip to a frozen lockup may be obtainedIntroduciton of MachiningHave a shape as a processing method, all machining process for the production of the most commonly used and most important method. Machining process is a process generated shape, in this process, Drivers device on the workpiece material to be in the form of chip removal. Although in some occasions, the workpiece under no circumstances, the use of mobile equipment to the processing, However, the majorityof the machining is not only supporting the workpiece also supporting tools and equipment to complete. Machining know the process has two aspects. Small group of low-cost production. For casting, forging and machining pressure, every production of a specific shape of the workpiece, even a spare parts, almost have to spend the high cost of processing. Welding to rely on the shape of the structure, to a large extent, depend on effective in the form of raw materials. In general, through the use of expensive equipment and without special processing conditions, can be almost any type of raw materials, mechanical processing to convert the raw materials processed into the arbitrary shape of the structure, as long as the external dimensions large enough, it is possible. Because of a production of spare parts, even when the parts and structure of the production batch sizes are suitable for the original casting, Forging or pressure processing to produce, but usually prefer machining Strict precision and good surface finish, Machining the second purpose is the establishment of the high precision and surface finish possible on the basis of Many parts, if any other means of production belonging to the largescale production, Well Machining is a low-tolerance and can meet the requirements of small batch production. Besides, many parts on the production and processing of coarse process to improve its general shape of the surface. It is only necessary precision and choose only the surface machining. For instance, thread, in addition to mechanical processing, almost no other processing method for processing. Another example is the blacksmith pieces keyhole processing, as well as training to be conducted immediately after the mechanical completion of the processing.Primary Cutting ParametersCutting the work piece and tool based on the basic relationship between the following four elements to fully describe : the tool geometry, cutting speed, feed rate, depth and penetration of a cutting tool. Cutting Tools must be of a suitable material to manufacture, it must be strong, tough hard and wear-resistant. Tool geometry - to the tip plane and cutter angle characteristics - for each cutting process must be correct. Cutting speed is the cutting edge of work piece surface rate, it is inches per minute to show. In order to effectively processing, and cutting speed must adapt to the level of specific parts - with knives. Generally, the more hard work piece materialthe lower the rate. Progressive Tool to speed is cut into the work piece speed. If the work piece or tool for rotating movement, feed rate per round over the number of inches to the measurement. When the work piece or tool for reciprocating movement and feed rate on each trip through the measurement of inches. Generally, in other conditions, feed rate and cutting speed is inversely proportional to。 Depth of penetration of a cutting tool - to inches dollars - is the tool to the work piece distance. Rotary cutting it to the chip or equal to the width of the linear cutting chip thickness. Rough than finishing, deeper penetration of a cutting tool depth.Wears of Cutting To01We already have been processed and the rattle of the countless cracks edge tool we learn that tool wear are basically three forms : flank wear, the former flank wear and V-Notch wear. Flank wear occurred in both the main blade occurred vice blade On the main blade, shoulder removed because most metal chip mandate, which resulted in an increase cutting force and cutting temperature increase, If not allowed to check, That could lead to the work piece and the tool vibration and provide for efficient cutting conditions may no longer exist. Vicebladed on, it is determined work piece dimensions and surface finish. Flank wear size of the possible failure of the product and surface finish are also inferior. In most actual cutting conditions, as the principal in the former first deputy flank before flank wear, wear arrival enough, Tool will be effective, the results are made unqualified partsAs Tool stress on the surface uneven, chip and flank before sliding contact zone between stress, in sliding contact the start of the largest, and in contact with the tail of zero, so abrasive wear in the region occurred. This is because the card cutting edge than the nearby settlements near the more serious wear, and bladed chip due to the vicinity of the former flank and lost contact wear lighter. This resultsfrom a certain distance from the cutting edge of the surface formed before the knife point Ma pit, which is usually considered before wear. Under normal circumstances, this is wear cross-sectional shape of an arc. In many instances and for the actual cutting conditions, the former flank wear compared to flank wear light, Therefore flank wear more generally as a tool failure of scale signs. But because many authors have said in the cutting speed of the increase, Maeto surface temperature than the knife surface temperatures have risen faster. but because any form of wear rate is essentially temperature changes by the significant impact. Therefore, the former usually wear in high-speed cutting happen The main tool flank wear the tail is not processed with the work piece surface in contact, Therefore flank wear than wear along with the ends more visible, which is the most common. This is because the local effect, which is as rough on the surface has hardened layer, This effect is by cutting in front of the hardening of t he work piece. Not just cutting, and as oxidation skin, the blade local high temperature will also cause this effect. This partial wear normally referred to as pit sexual wear, but occasionally it is very serious. Despite the emergence of the pits on the Cutting Tool nature is not meaningful impact, but often pits gradually become darker If cutting continued the case, then there cutter fracture crisis If any form of sexual allowed to wear, eventually wear rate increase obviously will be a tool to destroy failure destruction, that will no longer tool for cutting, cause the work piece scrapped, it is good, can cause serious damage machine. For various carbide cutting tools and for the various types of wear, in the event of a serious lapse, on the tool that has reached the end of the life cycle. But for various high-speed steel cutting tools and wear belonging to the non-uniformity of wear, has been found : When the wear and even to allow for a serious lapse, the most meaningful is that the tool can re-mill use, of course, In practice, cutting the time to use than the short time lapse. Several phenomena are one tool serious lapse began features : the most common is the sudden increase cutting force, appeared on the work piece burning ring patterns and an increase in noise.The Effect of Changes in Cutting Parameters on Cutting TemperaturesIn metal cutting operations heat is generated in the primary and secondary defo