低速載貨汽車變速器的設(shè)計(jì)[三軸四檔手動(dòng)][農(nóng)用運(yùn)輸車] 整備選約1.6噸 總3.5噸

低速載貨汽車變速器的設(shè)計(jì)[三軸四檔手動(dòng)][農(nóng)用運(yùn)輸車] 整備選約1.6噸 總3.5噸,三軸四檔手動(dòng),農(nóng)用運(yùn)輸車,低速載貨汽車變速器的設(shè)計(jì)[三軸四檔手動(dòng)][農(nóng)用運(yùn)輸車],整備選約1.6噸,總3.5噸,低速,載貨,汽車,變速器,設(shè)計(jì),三軸四檔,手動(dòng),農(nóng)用,運(yùn)輸車,整備,1.6,3.5 文 獻(xiàn) 資 料 專 業(yè) 機(jī)械設(shè)計(jì)制造及其自動(dòng)化 學(xué) 生 姓 名 陳 中 班 級(jí) B機(jī)制021 學(xué) 號(hào) 0260110101 指 導(dǎo) 教 師 李 書 偉 文 獻(xiàn) 資 料 ［1］蔡炳炎.機(jī)械式汽車變速器的速比配置分析[J]. 機(jī)械研究與應(yīng)用,2005，（4）：19-21. ［2］周長城.農(nóng)用運(yùn)輸車動(dòng)力傳動(dòng)系統(tǒng)系列化最佳匹配的研究[J].農(nóng)業(yè)機(jī)械報(bào),1996，（6）：24-29. ［3］張孝祖.1t級(jí)農(nóng)用運(yùn)輸車發(fā)動(dòng)機(jī)－傳動(dòng)系的合理匹配[J]. 江蘇理工大學(xué)，1995，（11）：32-37. ［4］陳家瑞.汽車構(gòu)造.（上冊(cè)）[M].北京：機(jī)械工業(yè)出版社，2005. ［5］陳家瑞.汽車構(gòu)造.（下冊(cè)）[M].北京：機(jī)械工業(yè)出版社，2005. ［6］QC/T29063-1992，汽車機(jī)械式變速器總成技術(shù)條件[S]. ［7］QC/T580-1999，汽車變速器安裝尺寸[S]. ［8］JB/T8582.3-2001,農(nóng)用運(yùn)輸車 機(jī)械式變速器[S]. ［9］JB/T7234-2001，四輪農(nóng)用運(yùn)輸車通用技術(shù)條件[S]. ［10］GB18320-2001，農(nóng)用運(yùn)輸車安全技術(shù)條件[S]. ［11］GB7258-2004，機(jī)動(dòng)車運(yùn)行安全技術(shù)條件[S]. ［12］汽車工程手冊(cè)編輯委員會(huì).汽車工程手冊(cè)(設(shè)計(jì)篇)[M].北京:人民交通出版社,2001. ［13］劉惟信.汽車設(shè)計(jì)[M].北京:清華大學(xué)出版社,2001. 畢業(yè)實(shí)習(xí)報(bào)告 專 業(yè) 機(jī)械設(shè)計(jì)制造及其自動(dòng)化 學(xué) 生 姓 名 陳 中 班 級(jí) B機(jī)制021 學(xué) 號(hào) 0260110101 指 導(dǎo) 教 師 李 書 偉 日 期 2006年３月18 日 畢 業(yè) 實(shí) 習(xí) 報(bào) 告 一、概述 畢業(yè)實(shí)習(xí)是學(xué)生完成大學(xué)四年全部課程后的一個(gè)很重要的環(huán)節(jié),也是一個(gè)不可缺少的階段，可以說起到了承前啟后的作用。畢業(yè)實(shí)習(xí)讓我們對(duì)所學(xué)的課本知識(shí)進(jìn)行了實(shí)踐性的操作，為整個(gè)畢業(yè)設(shè)計(jì)的完成奠定了堅(jiān)實(shí)的基礎(chǔ)。畢業(yè)實(shí)習(xí)的目的是讓學(xué)生直接接觸企業(yè),深入到生產(chǎn)第一線,了解企業(yè)運(yùn)營過程中存在的問題和改革的難點(diǎn)；了解新技術(shù)，新設(shè)備的應(yīng)用，開闊眼界；了解專業(yè)化生產(chǎn)的先進(jìn)技術(shù)與管理，圍繞畢業(yè)設(shè)計(jì)課題進(jìn)一步了解相關(guān)的知識(shí)和進(jìn)行資料的收集，在調(diào)查研究的過程中提高應(yīng)用專業(yè)知識(shí)和撰寫工作報(bào)告的能力；同時(shí)，了解產(chǎn)品的設(shè)計(jì)、生產(chǎn)過程中的質(zhì)量分析問題及可能影響生產(chǎn)的工藝、設(shè)備等問題，為完成畢業(yè)設(shè)計(jì)課題任務(wù)提供了必要條件，從而使學(xué)生的思維開闊，設(shè)計(jì)過程中合理地分配時(shí)間和安排進(jìn)度，保質(zhì)保量地完成畢業(yè)設(shè)計(jì)。 二、實(shí)習(xí)過程 根據(jù)學(xué)校對(duì)畢業(yè)班的要求，在畢業(yè)設(shè)計(jì)程序正式啟動(dòng)之前，學(xué)校給我們安排了兩周的工廠實(shí)習(xí)，具體過程如下：在江蘇江淮動(dòng)力股份有限公司實(shí)習(xí)了解了柴油機(jī)的生產(chǎn)工藝流程；在江蘇悅達(dá)鹽城拖拉機(jī)制造有限公司和江蘇悅達(dá)專用車有限公司實(shí)習(xí)了解了拖拉機(jī)和垃圾車的生產(chǎn)與裝配工藝；在東風(fēng)悅達(dá)起亞有限公司實(shí)習(xí)了解了轎車的沖壓、焊裝、總裝等先進(jìn)工藝生產(chǎn)線；在鹽城市機(jī)床有限公司實(shí)習(xí)了解了Z32K-1萬向搖臂鉆床，CDJK6140，CMK6140數(shù)控車床，XZ5020鉆銑床的制造工藝。 三、實(shí)習(xí)內(nèi)容 3月9日我們?cè)诶蠋煹膸ьI(lǐng)下，首先來到了江蘇江淮動(dòng)力股份有限公司，該公司是高科技民營企業(yè)——重慶東銀集團(tuán)旗下專業(yè)生產(chǎn)中、小功率發(fā)動(dòng)機(jī)的大型企業(yè)，位居中國企業(yè)500強(qiáng)、中國農(nóng)機(jī)行業(yè)上市公司之列。主要設(shè)備包括5t沖天爐7座、鑄造造型線6條、熱處理井式爐11座、氮化爐1座、進(jìn)口激光掃描儀1臺(tái)、進(jìn)口激光快速成型機(jī)1臺(tái)、進(jìn)口臥式加工中心兩臺(tái)、進(jìn)口立式加工中心5臺(tái)，進(jìn)口電火花成型機(jī)兩臺(tái)、進(jìn)口鋅鋁合金壓鑄機(jī)11臺(tái)套、各類精密數(shù)顯鏜床5臺(tái)套及多臺(tái)各類型號(hào)的車床、銑床、刨床、線切割機(jī)床等。該公司長期注重技術(shù)創(chuàng)新，投資億元建成省級(jí)企業(yè)技術(shù)中心和國家級(jí)博士后科研工作站，建有具有國際先進(jìn)水平CAD/CAM/CAT（計(jì)算機(jī)輔助設(shè)計(jì)、制造、測(cè)試）網(wǎng)絡(luò)，擁有行業(yè)首家以三維激光實(shí)體掃描儀、三維激光成型機(jī)等先進(jìn)設(shè)備和計(jì)算機(jī)軟件為代表的RP技術(shù)，積極引進(jìn)應(yīng)用同步開發(fā)、虛擬設(shè)計(jì)、快速原型制造、反求工程等高新技術(shù)改造傳統(tǒng)產(chǎn)業(yè)和傳統(tǒng)產(chǎn)品，確立了企業(yè)在行業(yè)技術(shù)進(jìn)步方面的領(lǐng)先地位。產(chǎn)品創(chuàng)新著著領(lǐng)先同行，逐步形成了具有自主版權(quán)和江動(dòng)特色的輕型多缸機(jī)、節(jié)能單缸機(jī)、小型汽油機(jī)、小馬力單缸機(jī)和發(fā)電機(jī)組（柴、汽油）五大系列，400多個(gè)品種的優(yōu)化產(chǎn)品結(jié)構(gòu)。? 3月10日上午我們來到了江蘇悅達(dá)鹽城拖拉機(jī)制造有限公司（原江蘇悅達(dá)鹽城拖拉機(jī)廠），該公司是中國中、小馬力拖拉機(jī)的重點(diǎn)企業(yè)之一。該公司技術(shù)力量雄厚，生產(chǎn)設(shè)備精良，加工工藝先進(jìn)，測(cè)試手段齊全，質(zhì)量保證體系完善，具有較強(qiáng)的產(chǎn)品開發(fā)與制造能力。具備年產(chǎn)8萬臺(tái)手扶拖拉機(jī)和3萬臺(tái)輪式拖拉機(jī)的能力。主要產(chǎn)品有：黃海牌-12型、151型、81型系列手扶拖拉機(jī)和黃海金馬-180、200、220、250、300、350、400、450、500、550、700、720、750系列及四輪驅(qū)動(dòng)系列輪式拖拉機(jī)。下午我們來到了江蘇悅達(dá)專用車有限公司，該公司系江蘇悅達(dá)集團(tuán)和世界500強(qiáng)企業(yè)日本富士重工業(yè)株式會(huì)社合作，全面引進(jìn)國際領(lǐng)先的垃圾車生產(chǎn)、制造和管理的專業(yè)生產(chǎn)后壓縮式垃圾車的制造企業(yè)?，F(xiàn)有沖壓、焊接、總裝、涂裝、檢測(cè)等先進(jìn)設(shè)備工藝。主導(dǎo)產(chǎn)品有YD5070ZYS型壓縮式垃圾車、YD5140ZYS型壓縮式垃圾車YD5120ZYS型壓縮式垃圾車、YD5130ZYS型壓縮式垃圾車和YD5110ZYS型壓縮式垃圾車。以上各型號(hào)垃圾車擁有先進(jìn)高效的液壓系統(tǒng)設(shè)計(jì)，提高作業(yè)效率； 可靠的PLC電控系統(tǒng)，機(jī)電液一體化控制，自動(dòng)化程度高； 專有的反R裝載軌跡，雙向壓縮，裝載效率高（專利技術(shù)）； 上裝部分采用專用高強(qiáng)度防腐鋼板，提高了車輛使用壽命；駕駛室內(nèi)增設(shè)工作指示燈，操作方便； 刮板的動(dòng)態(tài)化設(shè)計(jì)，推刮料流暢輕松；排放達(dá)到歐Ⅲ、歐Ⅱ標(biāo)準(zhǔn)； 作業(yè)噪聲≤55分貝； 徹底解決“跑”、“冒”、“滴”、“漏”問題；尾部多處設(shè)有緊急停止裝置； 設(shè)有防止誤操作裝置（鎖緊器）； 車廂密封自鎖裝置； 作業(yè)安全棒保護(hù)裝置。 3月11日我們來到了東風(fēng)悅達(dá)起亞汽車有限公司，該公司現(xiàn)已建成沖壓、焊裝、涂裝、總裝、檢測(cè)等先進(jìn)工藝生產(chǎn)線，具備年產(chǎn)13萬輛轎車的生產(chǎn)能力。主產(chǎn)品遠(yuǎn)艦、嘉華、千里馬和賽拉圖系列轎車均引進(jìn)韓國起亞先進(jìn)技術(shù)精心打造而成，在中國的乘用車市場(chǎng)上呈現(xiàn)出極強(qiáng)的競(jìng)爭力。東風(fēng)悅達(dá)起亞的目標(biāo)是到2010年，共擁有6款產(chǎn)品，涵蓋中國消費(fèi)者的所有“ 乘用車 ”概念，成為在中國汽車市場(chǎng)占有重要地位的現(xiàn)代化、綜合性乘用車制造企業(yè)。在東風(fēng)悅達(dá)起亞汽車有限公司的實(shí)習(xí)過程中我詳細(xì)的觀察了汽車車身的沖壓工藝流程，并做了較為詳盡的記錄，使我對(duì)汽車的整個(gè)的生產(chǎn)與裝配有了濃厚的興趣。 3月13日是我們實(shí)習(xí)的最后的一站—鹽城市機(jī)床有限公司，該公司產(chǎn)品包括CDC，CDB，CC，CA，CL等系列臥式車床，Z32K-1萬向搖臂鉆床，CDJK6140，CMK6140數(shù)控車床，XZ5020鉆銑床，和各種專機(jī)。產(chǎn)品暢銷全國，并在歐美和東南亞有著廣闊的國際市場(chǎng)。在車間里我仔細(xì)的聆聽技術(shù)人員的講解，并對(duì)機(jī)床的制造工藝有了直觀的了解，對(duì)書本知識(shí)有了更深的體會(huì)。 四、車身沖壓工藝的分析 車身沖壓件的工藝特點(diǎn)： 對(duì)沖壓件工藝性影響最大的是形狀尺寸和精度要求。良好的沖壓工藝性應(yīng)能滿足產(chǎn)品質(zhì)量穩(wěn)定、材料節(jié)省、工序較少、模具加工方便、使用壽命較長、生產(chǎn)操作方便等要求。 制定沖壓工藝時(shí)，首先要分析沖壓件的工藝性，即根據(jù)有效狀態(tài)的產(chǎn)品數(shù)據(jù)或產(chǎn)品圖紙分析沖壓件結(jié)構(gòu)的合理性，設(shè)計(jì)出適合具體生產(chǎn)條件的最經(jīng)濟(jì)合理的方案，包括工序性質(zhì)、工序數(shù)、工序順序和工序合并等；確定毛坯的形狀、理論尺寸和落料方式。然后根據(jù)工藝方案和沖壓件的形狀特點(diǎn)、精度要求、生產(chǎn)批量、模具加工條件、生產(chǎn)操作習(xí)慣與安全性等確定沖壓設(shè)備。 1)車身沖壓件的一般工藝特點(diǎn) ①?zèng)_裁(落料、切邊、沖孔)：合理排樣，減少廢料；毛坯無尖角(無廢料沖裁除外)；避免過長的懸臂或狹槽：沖孔直徑、孔距及孔與邊緣之間的距離不宜過小。 ②拉延，成形：拉延半徑盡量放大；盡量避免異常復(fù)雜非對(duì)稱形狀的拉延件；壓邊圈寬度和高度盡量保持一致；合理布置拉延筋。 ③翻邊：翻邊圓角半徑不宜小于最小彎曲半徑，也不宜過大；長度不宜過??；已有孔分布在變形區(qū)域之外；考慮翻邊工序定位孔。 ④其它：在沒有主模型或拉延示意模型時(shí)，工藝方案應(yīng)能反映最基本的工作情況，包括各道工序沖壓件的工作位置和沖壓方向，基準(zhǔn)位置尺寸，工序分配，廢料刀的布置，檢測(cè)基準(zhǔn)系統(tǒng)RPS及車身焊接部位尺寸的控制，沖壓件在各道工序的定位必須一致，檢驗(yàn)測(cè)量基準(zhǔn)和車身焊接定位相互一致等。 2)骨架件的工藝特點(diǎn) 骨架件的作用在于提高車身的剛性，并連接或固定內(nèi)飾件及其它零件。骨架件的特點(diǎn)是形狀復(fù)雜、沖孔多、零件易回彈及扭曲。因此，確定骨架件的工藝方案時(shí)，應(yīng)根據(jù)它的特點(diǎn)設(shè)計(jì)，如合理安排沖孔的順序和考慮整形工序等。 3)外覆蓋件的工藝特點(diǎn) 外覆蓋件即車身外表面零件，外表面質(zhì)量要求嚴(yán)格。確定外覆蓋件工藝方案時(shí)，除了考慮車身沖壓件的一般工藝特點(diǎn)外，尤應(yīng)注意采取有效措施，以避免隆起、起皺、劃傷、壓痕等外表面缺陷，確定合適的沖壓方向和合理布置拉延筋，盡量避免預(yù)切工序。 4)車身沖壓件發(fā)展趨勢(shì) 由于CAD技術(shù)的應(yīng)用以及沖壓設(shè)備性能的提高，轎車沖壓件逐漸向一體化和大型化發(fā)展。目前很多轎車都采用了整體側(cè)圍，將原來由近十個(gè)零件組成的側(cè)圍設(shè)計(jì)成一個(gè)整體零件，一次沖壓而成，明顯減少車身沖壓件數(shù)量，減少裝配時(shí)間和成本。 五、實(shí)習(xí)感想 我針對(duì)畢業(yè)設(shè)計(jì)的要求，結(jié)合自己所學(xué)的理論知識(shí)深入到加工現(xiàn)場(chǎng)，有條理地記錄和整理了相關(guān)的資料。我對(duì)汽車的特點(diǎn)、功能、用途及其發(fā)展的前景和方向有了更多的了解；對(duì)企業(yè)的生產(chǎn)流程不再只是個(gè)概念，而是有了很清晰的認(rèn)識(shí)。這次實(shí)習(xí)也讓我意識(shí)到理論與實(shí)際之間的差距,理論只有通過實(shí)踐才能被更深刻的理解和掌握。 3 附件1 鹽城工學(xué)院優(yōu)秀畢業(yè)設(shè)計(jì)（論文）推薦表 院（系）名稱：機(jī)械工程學(xué)院 填表日期：2006年6月20日 學(xué)生 姓名 陳中 性別 男 民族 漢 出生 年月 1982.11 入學(xué) 年級(jí) 02級(jí) 專業(yè)名稱 機(jī)械制造及其自動(dòng)化 專業(yè)代碼 080201 備注 指導(dǎo)教師 畢業(yè)設(shè)計(jì)（論文）總周數(shù) 14 姓名 專業(yè)技術(shù)職務(wù) 年齡 所在單位 李書偉 高級(jí)工程師 40 機(jī)械工程學(xué)院 畢業(yè)設(shè)計(jì)（論文）題目 低速載貨汽車變速器的設(shè)計(jì) 畢業(yè)設(shè)計(jì)（論文）主要涉及研究方向 1、 參與總體設(shè)計(jì)； 2、 變速器結(jié)構(gòu)型式分析和主要參數(shù)的確定； 3、 變速器結(jié)構(gòu)設(shè)計(jì)； 4、 用AUTOCAD繪制二維工程圖。 畢業(yè)設(shè)計(jì)（論文）選題依據(jù)及背景 根據(jù)專業(yè)方向和畢業(yè)設(shè)計(jì)要求，從國家“三農(nóng)”和汽車產(chǎn)業(yè)政策出發(fā)，盡量結(jié)合工程生產(chǎn)實(shí)際，依據(jù)相關(guān)國家或行業(yè)標(biāo)準(zhǔn)。 學(xué)校中期檢查情況 畢業(yè)設(shè)計(jì)（論文）的水平與特色 方案正確，分析合理，工藝可行，具有實(shí)用價(jià)值。 典型輕型貨車NJ130系列的變速器齒輪大多采用非標(biāo)準(zhǔn)齒輪，本次設(shè)計(jì)的變速器齒輪等零部件貫徹了國家或行業(yè)的最新標(biāo)準(zhǔn)，具有較好的加工和使用性能，結(jié)構(gòu)緊湊、使用維修方便，并可附裝取力機(jī)構(gòu)供用戶的特殊需要。 畢業(yè)設(shè)計(jì)（論文）有何實(shí)驗(yàn)、實(shí)踐或?qū)嵙?xí)基礎(chǔ) 到相關(guān)企業(yè)進(jìn)行參觀實(shí)習(xí)，努力保證設(shè)計(jì)實(shí)際可行。 學(xué)生畢業(yè)設(shè)計(jì)（論文）期間的研讀書目 [1] GB7258-2004，機(jī)動(dòng)車運(yùn)行安全技術(shù)條件[S]. 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[13] 席新明.四輪農(nóng)用運(yùn)輸車使用維修圖解[M].鄭州：河南科學(xué)技術(shù)出版社，2002. 指導(dǎo)教師評(píng)語及推薦意見（包括學(xué)生的工作態(tài)度、知識(shí)與能力、成果與水平、設(shè)計(jì)（論文）質(zhì)量等幾方面） 該生設(shè)計(jì)期間出勤率高，學(xué)習(xí)態(tài)度端正，工作努力、嚴(yán)謹(jǐn)、踏實(shí)；較好地進(jìn)行文獻(xiàn)查閱、資料收集；提出合理的實(shí)施方案，進(jìn)行設(shè)計(jì)與計(jì)算，并不斷改進(jìn)，精益求精，按要求完善，圓滿完成規(guī)定任務(wù)；綜合運(yùn)用知識(shí)能力較強(qiáng)；方案可行，計(jì)算正確規(guī)范且完整，成果質(zhì)量水平較好。 指導(dǎo)教師簽字： 年 月 日 指導(dǎo)教師對(duì)申報(bào)材料真實(shí)性的意見 申報(bào)材料真實(shí)可靠。 指導(dǎo)教師簽字： 年 月 日 院(系) 推薦意見 院(系)公章 年 月 日 注：專業(yè)代碼和專業(yè)名稱應(yīng)按教育部公布的專業(yè)目錄填寫。 現(xiàn)設(shè)的相應(yīng)專業(yè)名稱如與之不同，請(qǐng)?jiān)凇皞渥ⅰ睓谥凶⒚鳌? 機(jī)械工程學(xué)院畢業(yè)設(shè)計(jì)（論文）選題申報(bào)表 指導(dǎo)教師 李書偉 學(xué)生姓名　陳中 2005 年 12 月 12 日 設(shè)計(jì)（論文） 題 目 低速載貨汽車變速器的設(shè)計(jì) 題目類型 畢業(yè)設(shè)計(jì) 題目來源 結(jié)合生產(chǎn)實(shí)際 題目性質(zhì) 工程設(shè)計(jì) 設(shè)計(jì)原始數(shù)據(jù) 根據(jù)相關(guān)技術(shù)規(guī)范和標(biāo)準(zhǔn)確定 設(shè)計(jì)內(nèi)容 1、 參與總體設(shè)計(jì)； 2、 變速器結(jié)構(gòu)型式分析和主要參數(shù)的確定； 3、 變速器結(jié)構(gòu)設(shè)計(jì)； 4、 用AUTOCAD編制二維工程圖。 物化成果形式 □工程設(shè)計(jì) 類要求 說明書字?jǐn)?shù) 圖紙數(shù) 其他附件 □工程研究 類要求 論文字?jǐn)?shù) 附件要求 □軟件開發(fā) 類要求 說明書字?jǐn)?shù) 附件要求 1）說明書字?jǐn)?shù):不少于1.0萬字 2）圖紙數(shù)：折合A0不少于3張，其中裝配圖不少于1張，且全部用AUTOCAD二維出圖。 系部審查意見： 系主任（簽名）： 學(xué)院審批意見： 學(xué)院院長（簽名）： 注：內(nèi)容較多可另附紙說明 鹽城工學(xué)院本科生優(yōu)秀畢業(yè)設(shè)計(jì)選編 低速載貨汽車變速器的設(shè)計(jì) 機(jī)械設(shè)計(jì)制造及其自動(dòng)化 （0260110101） 陳中 指導(dǎo)老師：李書偉 摘 要：課題來源于生產(chǎn)實(shí)際，依據(jù)《機(jī)動(dòng)車安全技術(shù)條件》和《汽車機(jī)械變速器總成技術(shù)條件》，針對(duì)低速載貨汽車的運(yùn)行特點(diǎn)而設(shè)計(jì)。參與了汽車的總體設(shè)計(jì)，確定了汽車的質(zhì)量參數(shù)，選擇了合適的發(fā)動(dòng)機(jī)，并且計(jì)算出汽車的最高速度。關(guān)于變速器的設(shè)計(jì)，首先選擇標(biāo)準(zhǔn)的齒輪模數(shù)，在總檔位和一檔速比確定后，合理分配變速器各檔位的速比，接著計(jì)算出齒輪參數(shù)和中心距，并對(duì)齒輪進(jìn)行強(qiáng)度驗(yàn)算，確定了齒輪的結(jié)構(gòu)與尺寸，繪制出所有齒輪的零件圖。根據(jù)經(jīng)驗(yàn)公式初步計(jì)算出軸的尺寸，然后對(duì)每個(gè)檔位下軸的剛度和強(qiáng)度進(jìn)行驗(yàn)算，確定出軸的結(jié)構(gòu)和尺寸，繪制出各根軸的零件圖。根據(jù)結(jié)構(gòu)布置和參考同類車型的相應(yīng)軸承后，按國家標(biāo)準(zhǔn)選擇合適的軸承，然后對(duì)軸承進(jìn)行使用壽命的驗(yàn)算，最終完成了變速器的零件圖和裝配圖的繪制。此變速器的齒輪都為標(biāo)準(zhǔn)齒輪，檔位數(shù)和傳動(dòng)比與發(fā)動(dòng)機(jī)參數(shù)匹配，保證了汽車具有良好的動(dòng)力性和經(jīng)濟(jì)性。該變速器具有操縱簡單、方便、傳動(dòng)效率高、制造容易、成本低廉、維修方便的特點(diǎn)，適合低速載貨汽車的使用。 關(guān)鍵詞：低速載貨汽車；變速器；設(shè)計(jì) Abstract: The topic comes from the production reality, which is based on the safety specifications for power driven vehicles operating on roads and the specifications for the automobile mechanical transmission. It designs the low-speed truck’s movement characteristic. The automobile quality parameters are determined, according to the automobile system design, choosing the appropriate engine, and calculating the maximum speed. When design the transmission, first, we choose the standard gear modulus and determine all speed’s proportions after we choose the number of the transmission’s gears and the first gear, then calculate the gear’s parameter and the center distance, and the gear needs the intensity checking calculation. We determine gear’s structure, then complete drawing of the gears’ component. According to the empirical formula, we preliminary carry on the checking calculation to each gear’s rigidity and the intensity to determine the axis’ structure and size, and thus draw up various axis’ component drawing. After arranged structure and compared with the similar type of vehicle’s bearing, according to the national standard, we select the appropriate bearings, and then calculate the service life of the bearings. Finally drawing of the component and the assembly of the transmission are completed. Because the transmission gear is the standard gear and the number of gears and speed’s proportions match to the engine conditions, which ensure the necessary power and economy. This transmission has many merits of simple operation, efficient, easy manufacturing, low cost, and convenient. Key words: Low-speed Truck；Transmission；Design 1 前言 本課題為低速載貨汽車變速器的設(shè)計(jì)，該課題來源于結(jié)合生產(chǎn)實(shí)際。研究的主要內(nèi)容是：參與汽車的總體設(shè)計(jì)；變速器結(jié)構(gòu)型式分析和主要參數(shù)的確定；變速器結(jié)構(gòu)設(shè)計(jì)。本說明書以設(shè)計(jì)低速載貨汽車變速器的傳動(dòng)機(jī)構(gòu)為主線。第2章著重介紹了在參與總體設(shè)計(jì)當(dāng)中，如何確定低速載貨汽車參數(shù)，進(jìn)而明確變速器應(yīng)滿足的條件及其所受的限制。第3章則重點(diǎn)介紹低速載貨汽車變速器的傳動(dòng)機(jī)構(gòu)的設(shè)計(jì)說明。在參與總體設(shè)計(jì)當(dāng)中，首先是對(duì)低速載貨汽車的產(chǎn)品技術(shù)規(guī)范和標(biāo)準(zhǔn)進(jìn)行分析，然后確定低速載貨汽車的總質(zhì)量，以此來選擇合適的發(fā)動(dòng)機(jī)。根據(jù)發(fā)動(dòng)機(jī)的功率以及汽車的總質(zhì)量確定該車的最高速度（滿足低速載貨汽車安全技術(shù)條件）。關(guān)于變速器的設(shè)計(jì)，首先選擇合適的變速器確定其檔位數(shù)，接著對(duì)工況進(jìn)行分析，擬訂變速器的各檔位的傳動(dòng)比和中心距，然后計(jì)算出齒輪參數(shù)以選擇合適的齒輪并且對(duì)其進(jìn)行校核，接著是初選變速器軸與軸承并且完成對(duì)軸和軸承的校核，最終完成了變速器的零件圖和裝配圖的繪制。 2 低速載貨汽車主要參數(shù)的確定 2.1 質(zhì)量參數(shù)的確定 本課題通過計(jì)算選用ma=3500kg。 2.2 發(fā)動(dòng)機(jī)的選型 針對(duì)本次設(shè)計(jì)任務(wù)選用達(dá)到歐Ⅱ排放標(biāo)準(zhǔn)的YD480柴油機(jī)。 2.3 車速的確定 計(jì)算出Vmax≈62.3km/h,所以該車車速滿足要求。 3 變速器的設(shè)計(jì)與計(jì)算 3.1 設(shè)計(jì)方案的確定 3.1.1 兩軸式 這種結(jié)構(gòu)適用于發(fā)動(dòng)機(jī)前置、前輪驅(qū)動(dòng)或發(fā)動(dòng)機(jī)后置、后輪驅(qū)動(dòng)的轎車和微、輕型貨車上，其特點(diǎn)是輸入軸和輸出軸平行，無中間軸。 3.1.2 三軸式 它的第一軸常嚙合齒輪與第二軸的各檔齒輪分別與中間軸的相應(yīng)齒輪相嚙合，且第一、二軸同心。適用于傳統(tǒng)的發(fā)動(dòng)機(jī)前置、后輪驅(qū)動(dòng)的布置形式。 3.1.3 液力機(jī)械式 由液力變矩器和齒輪式有級(jí)變速器組成,其特點(diǎn)是傳動(dòng)比可在最大值和最小值之間的幾個(gè)間斷范圍內(nèi)作無級(jí)變化，但結(jié)構(gòu)復(fù)雜，造價(jià)高，傳動(dòng)效率低。 3.1.4 確定方案 由于低速載貨汽車一般是傳統(tǒng)的發(fā)動(dòng)機(jī)前置，后輪驅(qū)動(dòng)的布置形式，同時(shí)考慮到制造成本以及便于用戶維護(hù)等因素，現(xiàn)選用三軸式變速器。 3.2 零部件的結(jié)構(gòu)分析 通過對(duì)齒輪型式、軸的結(jié)構(gòu)、軸承型式的分析，來確定所有零件的結(jié)構(gòu)。 3.3 基本參數(shù)的確定 3.3.1 變速器的檔位數(shù)和傳動(dòng)比 選擇最低檔傳動(dòng)比時(shí)，應(yīng)根據(jù)汽車最大爬坡度、驅(qū)動(dòng)車輪與路面的附著力、汽車的最低穩(wěn)定車速以及主減速比和驅(qū)動(dòng)車輪的滾動(dòng)半徑等來綜合考慮、確定。它可以根據(jù)汽車最大爬坡度計(jì)算，也可以根據(jù)驅(qū)動(dòng)車輪與路面的附著條件計(jì)算。 3.3.2 中心距 商用車變速器的中心距約在80～170mm范圍內(nèi)變化,初選A=100mm。 3.3.3 變速器的軸向尺寸 初選軸向尺寸:（2.4～2.8）A=（2.4～2.8）×100=240～280mm。 3.3.4 齒輪參數(shù) 通過計(jì)算并參照同類車型選取標(biāo)準(zhǔn)模數(shù)m=3.5，所有齒輪采用標(biāo)準(zhǔn)齒輪。 3.3.5 各檔齒輪齒數(shù)的分配 首先確定Ⅰ檔齒輪的齒數(shù)，然后修正中心距A=（3.5×60）/2=105mm，接著確定常嚙合傳動(dòng)齒輪副的齒數(shù)，以及其他檔位的齒輪齒數(shù)，最后確定倒檔齒輪副的齒數(shù)。 3.4 齒輪的設(shè)計(jì)計(jì)算 3.4.1 幾何尺寸計(jì)算 分別根據(jù)齒數(shù)和模數(shù)計(jì)算出尺寸。 3.4.2 齒輪的材料及熱處理 本課題變速器齒輪選用材料是20CrMnTi，采用滲碳處理。 3.4.3 齒輪的彎曲強(qiáng)度 因?yàn)樵撟兯倨魉械凝X輪采用同一種材料，所以當(dāng)校核時(shí)只要校核受力最大和危險(xiǎn)的檔位齒輪。分別計(jì)算出Ⅰ檔、倒檔齒輪的彎曲強(qiáng)度且都滿足要求。 3.4.4 齒輪的接觸強(qiáng)度 常嚙合齒輪副，Ⅰ檔、Ⅱ檔、Ⅲ檔、倒檔的齒輪都滿足強(qiáng)度要求。 3.5 軸的設(shè)計(jì)與軸承的選擇 3.5.1 軸的設(shè)計(jì) 軸的尺寸可按關(guān)系式初選。首先校核第二軸在各檔位下的強(qiáng)度與剛度，然后校核中間軸在各檔位下的強(qiáng)度與剛度，最后校核倒檔軸的強(qiáng)度與剛度。 3.5.2 軸承的選擇 第一軸后軸承為6209軸承,第二軸后軸承為6307軸承。第二軸前端選用無套圈長圓柱滾子軸承,型號(hào)為:KNL20.612×33.325×35；在中間軸上與中間軸齒輪配合的軸承，也選用該種軸承，型號(hào)為：KNL25.4×41.208×60.4。 4 結(jié)論 本課題是針對(duì)低速載貨汽車而設(shè)計(jì)的變速器，基于經(jīng)濟(jì)實(shí)用的考慮，變速器采用手動(dòng)機(jī)械變速，三軸式傳動(dòng)機(jī)構(gòu)布置方案，有四個(gè)前進(jìn)檔和一個(gè)倒檔。典型輕型貨車NJ130系列的變速器齒輪大多采用非標(biāo)準(zhǔn)齒輪，本次設(shè)計(jì)的變速器齒輪等零部件貫徹了國家或行業(yè)的最新標(biāo)準(zhǔn)，具有較好的加工和使用性能，結(jié)構(gòu)緊湊、使用維修方便，并可附裝取力機(jī)構(gòu)供用戶的特殊需要。 隨著城鄉(xiāng)路況的好轉(zhuǎn)，以及人們對(duì)乘車舒適性的要求越來越高，日后可以考慮采用常嚙合斜齒輪傳動(dòng)，同步器換檔的變速器，而且可以增加一個(gè)超速檔，這樣可以使汽車的動(dòng)力性和經(jīng)濟(jì)性有更大地提高。 主要參考文獻(xiàn) [1] GB7258-2004，機(jī)動(dòng)車運(yùn)行安全技術(shù)條件[S]. [2] GB18320-2001，農(nóng)用運(yùn)輸車安全技術(shù)條件[S]. [3] 王望予.汽車設(shè)計(jì)[M].北京：機(jī)械工業(yè)出版社，2000. [4] 劉惟信.汽車設(shè)計(jì)[M].北京：清華大學(xué)出版社,2001. [5] 陳家瑞.汽車構(gòu)造.（下冊(cè)）[M].北京：機(jī)械工業(yè)出版社，2005. 3 Experimental analysis of a composite automotive suspension arm M. PINFOLD and G. CALVERT (University of Warwick/Rover Group Gaydon, UK) Received 11 November 1992; revised 26 March 1993 In applications where weight saving and parts integration can be achieved, the Rover Group has been investigating the design and manufacture of components from composite materials. The methods used in the different steps in the design- to-manufacture cycle in the high volume automotive industry are relatively well known for a steel component, but are not so well established for a composite component. A design methodology for composites has been emerging in which a principal procedure is design analysis. One of the most established methods of analysisis that using the finite element technique, and this is being supplemented with experimental tests on prototypes using photoelastic analysis and stress pat- tern analysis by thermal emission, coupled with conventional strain gauge moni- toring. Little work has been undertaken to correlate the results obtained from these different test methods and to compare the results with measurements made on an actual component. This paper presents some of the work undertaken concerning the analysis and testing of a composite automotive suspension arm. The results obtained from the three different analysis techniques are compared with experi- mental test results, and their accuracy is discussed. Key words: autmotive suspension arm; stress analysis; finite element method; photoelastic analysis; SPA TE; strain gauges; sheet moulding compound Sol and de Wilde state that composite materials have been used increasingly as structural materials. A reason for this., is that composite materials have high strength to weight and high stiffness to weight ratios which can significantly reduce the weight of a structure. Perhaps the most important feature ofcomposite materials is that their mechanical p:operties can be tailored to meet a specific criterion. However, Johnson et al? suggest that composite design, analysis and fabrication technology must undergo major developments and successful demonstrations before significant structural components will be incorporated in production automobiles and trucks. Composite materials have to compete with steel within the engineering environment. Within the automotive industry this requires a certain amount of technology transfer from places such as the Advanced Technology Centre at the University of Warwick, which work with material manufacturers and automotive engineers to enable understanding about these materials as an alter- native to the traditional materials such as steel. If com- posites are to compete with traditional materials in a real sense, then automotive designers need to be fully aware 0010-4361/94/010059-05 of their strengths and limitations so that they can be one of perhaps many options considered at the concept stage of the design. For this to happen automotive engineers need to catch up on the techniques of designing, testing and manufacturing components from composites. This will include understanding how various methods such as finite element (FE) analysis, stress pattern analysis by thermal emission (SPATE) and photoelastic analysis can be applied to composite components in their design and development. Thus far little work appears to have been undertaken to study whether the results obtained from these different analysis methods correlate with one another or with actual experimental results obtained from testing a real component. In order to study the application and corre- lation of the different analysis methods to composite materials, a composite component - an automotive lower suspension arm - was manufactured. This com- posite component was analysed by the three methods described above and also tested under realistic loading conditions, with experimental results being obtained from strain gauges. 1994 Butterworth-Heinemann ktd COMPOSITES . VOLUME 25 . NUMBER 1 . 1994 59 , B a l l J o i nt Housing Fig. 1 The composite suspension arm DESIGN The existing steel lower suspension arm consists of nine pieces welded together whilst the re-designed composite component-which can be seen in Fig. 1-is a single moulded part. The material used to manufacture the suspension arm was a sheet moulding compound (SMC), comprising a polyester resin bonding agent with a 30% content of randomly arranged short glass fibres and cal- cium carbonate fiIler. The weight of the steel suspension arm is 2.53 kg whilst the re-designed SMC suspension arm complete with bushes and ball joint weighs 1.5 kg. The material properties used for the composite suspension arm in these analyses, obtained from tests carried out at Rovers materials laboratory, were Youngs modulus = 10.5 GPa, Poissons ratio = 0.26 and density = 1.8 x 10 -6 kg mm -3. EXPERIMENTAL TECHNIQUES Prior to undertaking experimental analysis of an actual engineering component, some initial validation work was required to gain confidence in the techniques when applied to sheet moulding compound. Therefore, fiat plates, beams and discs constructed from SMC were ana- lysed under various loading conditions before progress- ing on to the designed component. Most validation tests were carried out using strain- gauged specimens to correlate with the finite element analysis results. Although it is recognized that SMC is not an isotropie material due to some fibre orientation during processing, for the purposes of analysis the mater- ial was assumed to be isotropic. Also, when the actual SMC suspension arm was cut up and examined, signifi- cant fibre distribution was observed in the ribs. It is felt that the correlation between the experimental and analy- sis results validated this assumption in the case of this particular component. Strain gauge tests Before undertaking the experimental test work, the com- posite component was mounted via its rubber mounting bushes onto a relatively infinitely stiff structure. It is very difficult to cover all of the loading conditions when con- ducting experimental tests and thus a worst-case scenario is usually assumed. The worst-case loading condition on suspension components is known as pot-hole brake. This attempts to simulate the vehicle falling into a deep pot-hole at 30 mph with the brakes fully applied at the point of impact. The resultant fore/aft and lateral loads are then calculated based on the weight and velocity of the vehicle. Due to the limitations of the test rig the full pot-hole loads could not be applied to the component, and thus reduced loads with the same resultant direction as the pot-hole loads were applied and the results scaled. The loads applied for the full pot-hole brake case were 24.2 kN in X and 8.2 kN in Y, and for the reduced load case were 5.9 kN in X and 2.02 kN in Y - see Fig. 1. The strain gauges used consisted of six three-axis rosette gauges and 13 single-grid gauges, with 2.5 mm grid lengths, chosen to fit into the radii of the component in an attempt to measure the maximum strain, Gauges were situated near the ball joint housing, where the loads were applied, and around the radii of the body mounting bushes, where the component would be mounted to the car subframe. Additional strain gauges were situated on some of the strengthening ribs and close to the anti-roll bar mounting position. SPA TE analysis Stress pattern analysis by thermal emission (SPATE) can be used to determine the surface stresses of components by studying the small changes in temperature due to cyclic loading conditions. SPATE equipment comprises a detector unit with scanning head, an analogue signal processing unit and a digital electronic data unit. The system works by detecting the minute temperature changes which occur when a structure is cyclically loaded. The infra-red detector scans the structure and correlates the measured output with a reference signal from the loading system. An electronic data processing system correlates the detected stress-induced thermal fluctuations with the loading reference signal. A colour contour map of the sum of the principal stresses (cr + 4) is then plotted, together with a bar chart giving actual values. This correlation of signals effectively eliminates all signal frequencies other than those caused by the loading system, i.e., all ambient temperature fluctua- tions. The SPATE system has a temperature resolution of 0.001C, and a spatial resolution of less than I mm. This type of analysis has been shown by a number of authors TM to also be applicable to non-isotropic mater- ials such as composites, and the small errors (6%) demonstrated from such studies when compared with theoretical or FE results are felt to be due to inaccuracies in the material data used 4. It is apparent from the studies undertaken that the use of thermoelastic stress analysis to evaluate stresses and strains in anisotropic composite materials is more complex than for isotropic materials. However, it has been shown that the technique can provide valuable qualitative information on stress distri- bution, effects of surface defects and crack growth predictions. It has also been demonstrated that, given accurate details of material properties including expan- sion coefficients, quantitative results can be obtained depending upon the degree of anisotropy of the material. Prior to undertaking a full SPATE analysis of the suspen- sion arm it was necessary to determine a calibration factor for the material used. This can be achieved in two ways, either by loading a disc of the material in compres- sion and comparing the SPATE output with the theoreti- 60 COMPOSITES. NUMBER 1 . 1994 cal solution, or by strain gauging directly onto the component in an area of even stress distribution, thereby obtaining a direct comparison with the SPATE output. Both methods were used in this case, but direct calib- ration with strain gauges can overcome a lot of the problems, thus allowing significant information to be obtained from the SPATE output. Photoelastic analysis The majority of photoelastic work investigating the mac- romechanical behaviour of composite materials has been undertaken using photoelastic coating techniques. This is done to avoid the complexities of constructing a photo- elastic model with anisotropic properties and thus con- structing a composite like the original which would lose its transparency and could not be analysed. However, for complex fibre lay-ups this would be the only method of conducting photoelastic analysis, and thus some research has been undertaken investigating the use of the actual composites j7-30. Reasonable results have been obtained from such analyses, but with limitations due to the neces- sity for transparency within the composite. However, the composite component considered in this study was manufactured from SMC and the material was assumed to be isotropic, thus simplifying the creation of a photo- elastic model. A three-dimensional epoxy resin model of the suspension arm was constructed for the photoelastic analysis. The model was then loaded in a representative manner, with scaled-down loads, and subjected to a stress freezing cycle. This involves heating the model up to the mater- ials glass transition temperature, at which point the Youngs modulus changes, and the model deforms under the applied loads. The model is then slowly cooled, avoiding any uneven temperature distribution which could result in unwanted thermal stresses. During the cooling cycle the deformations and stresses are locked into the model. When viewed under polarized light the three-dimensional model is a jumble of interference fringes. In order to determine both magnitude and direc- tion of the principal stresses at any point, a slice is removed and observed under polarized light. By count- ing the fringes the stresses in the model can be calculated and converted into actual stress in the component. This is done by means of proportionality, between the model and component materials, and the loading and dimensio- nal parameters. The lower suspension arm is mounted to the rest of the car via rubber mounting bushes. Investigations were carried out as to the possibility of modelling these mounting bushes. However, experiments with silicon and foam rubbers showed that the required scaled-down stiffness of the bushes during stress freezing at elevated temperatures could not be maintained. The photoelastic analysis thus assumed that the suspension arm was solidly mounted. FINITE ELEMENT ANAL YSIS The composite suspension arm was modelled using approximately 1300 of the STIF45 ANSYS solid ele- ments. The suspension arm is mounted to the subframe via rubber mounting bushes; these were modelled with spring elements to represent the stiffness of the bushes and to create a realistic load distribution throughout the component. Loads were applied to the FE model via beam elements at the ball joint. Three load cases were analysed using the ANSYS FE software. The first load case simulated the full pot-hole brake loads. The second simulated the reduced load used in the tests due to the limitations of the test rig, to enable comparisons with the results from the experimental strain gauge analysis. These two load cases used spring elements to simulate the stiffness of the rubber mounting bushes. The third load case again used the reduced loads but this time omitted the spring elements; i.e., the suspen- sion arm was modelled as being solidly mounted. This third load case was required to correlate with the SPATE and photoelastic analyses. RESUL TS Finite element analysis Analysis of the suspension arm showed that the maxi- mum equivalent stress in the component for the load case considered is very close to the ultimate tensile strength of the proposed material for the pot-hole loading condition, which is the worst loading condition. This means that the component may need to be manufactured from a differ- ent material, or that other materials need to be posit- ioned in areas of high stress to strengthen the component locally. Due to constraints upon the amount of computer disc space available, the number of elements used within the FE model was relatively low and thus the size of the elements within the area of the radii around the body mounting bushes was too large to detect any large stress concentrations. Also, the types of element used around these areas, due to the geometry of the component, were a mixture of brick, wedge and tetrahedral. The latter shape tends to be too stiff to give good results and is not recommended. If more detailed results were required in these areas, then these radii would have to be modelled in greater detail with more and smaller elements in the areas of high stress gradient. Photoelastic analysis The analysis of the photoelastic model of the suspension arm was undertaken assuming that the directions of the maximum principal stresses lay in a horizontal plane through the model in the direction of the fore/aft load. Whilst this is not strictly true in practice due to local geometry effects in certain areas, the assumption gave sufficiently accurate results. If obvious discrepancies were found in particular areas then it was possible to take slices from different planes. Maximum stresses were seen to occur in the vicinity of the ball joint housing and the body mounts. Due to the ability of photoelastic analysis to pinpoint very small areas of high stress, the maximum stress values given by photoelasticity tended to be higher than the strain gauge results. For example, maximum stress levels in the internal radius of the leading body mount were found to be 43 MPa compared with a SPATE value of 26 MPa. This difference can be explained by examin- ing the slice taken through the photoelastic model which shows that the maximum stress only occurs at a position COMPOSITES. NUMBER 1 . 1994 61 Table 1. Stress results (MPa) for full load con- ditions Position Strain gauges FE Photoelastic Ball joint housing 176 165 176 spanning 3 mm and that the stress values either side of the maximum are around 25 MPa. SPA TE analysis The initial SPATE scan showed large bands of stress running across the mounting areas and some confusion as to whether these areas were in tension or compression. The problem was identified as excessive movement in the suspension arm body mounting positions due to distor- tion of the rubber bushes as experienced in the strain gauge tests. SPATE is equipped with a motion compen- sator device if required, which deflects the scanning mirrors inside the detector in time with the oscillations of the test-piece, thereby eliminating the movement. How- ever, in this particular case, the geometry and direction of movement could not be eliminated over the entire area at the same time, and thus it was necessary to remove the rubber bushes and to replace them with aluminium ones. The SPATE analysis was repeated with the solid bushes and showed areas of high tensile stress (26 MPa) along the leading edge and around the inner radius of the leading body mounting position. Unfortunately, no SPATE analysis could be undertaken at the ball joint end of the component as it was obscured by the large loading adaptor required to fit the hydraulic actuator supplying the cyclic loading. COMPARISON OF RESULTS It should be clarified that the stress values quoted in the tables from the strain gauge results were calculated from the rosette gauges to give a value of maximum principal stress. The photoelastic analysis also gives maximum principal stresses unless the values are taken inboard of a free edge in which case they are differences in principal stresses (o.- o-,). SPATE analysis gives an output in the form of the summation of the principal stresses (or. + a2) whereas the FE output can be in any form required (in this case yon Mises). Due to the geometry of the compo- nent and the way in which the loads were applied, the values of or2 and cr 3 were always small, and thus direct comparisons could be made between the different analy- sis methods without further conversion. Table l compares the results obtained for the maximum pot-hole load conditions. The maximum stress values all occur at the ball joint area and correlate very well. These resultant stresses for the strain gauges and photoelasti- city were calculated from the results obtained for the reduced load. The model stress was multiplied by a load- ing factor as the ratio between the fore/aft and lateral loading remained constant and in the same proportion as the full pot-hole brake load applied to the suspension arlTI. The results of the analyses undertaken with reduced Table 2. Stress results (MPa) for redTJced loads with mounting bushes Position Strain gauges FE Inner radius of body 25 20 mount Ball joint housing 49 40 Table 3. Stress results (MPa) for reduced loads without mounting bushes Position FE SPATE Photoelastic Inner radius of body 22 mount Ball joint housing 30 26 43 (25) 42 (25) loading but with the mounting bushes included can be seen in Table 2. Table 3 presents the results of the analyses undertaken with reduced loading and without the mounting bushes being used. The stress given by the photoelastic analysis is concentrated at a very small point whereas the stress given by FE analysis is averaged over a relatively large area. In the case of the photoelastic results, an average of the nominal stresses on both sides of the concen- tration point is also quoted in brackets to give a fairer comparison. Compared with the strain gauge results, the values given by SPATE are very similar for the maximum stress. In theory SPATE should be more effective than strain gauges when investigating stress concentration effects, as it is measuring values over a smaller area depending upon its distance from the object during scanning. In this case the measurement point of SPATE was set at I mm diameter compared with a 2.5 mm grid le