草坪播種機(jī)的設(shè)計(jì)【7張CAD圖紙、說(shuō)明書完整打包】

購(gòu)買設(shè)計(jì)請(qǐng)充值后下載，資源目錄下的文件所見(jiàn)即所得，都可以點(diǎn)開(kāi)預(yù)覽，資料完整，充值下載可得到資源目錄里的所有文件。【注】：dwg后綴為CAD圖紙，doc,docx為WORD文檔，原稿無(wú)水印，可編輯。有不明白之處，可咨詢QQ:414951605 目 錄1 引 言12 技術(shù)任務(wù)書（JR）22.1 設(shè)計(jì)的依據(jù)22.2 產(chǎn)品的用途及使用范圍22.3 主要技術(shù)指標(biāo)和重要技術(shù)參數(shù)22.4 主要工作原理32.5 已經(jīng)考慮過(guò)的若干方案的比較32.6 關(guān)鍵問(wèn)題及其解決辦法42.7 機(jī)構(gòu)的功能及特點(diǎn)53 設(shè)計(jì)計(jì)算說(shuō)明書 （SS）53.1 草坪播種機(jī)結(jié)構(gòu)的方案設(shè)計(jì)53.1.1 傳動(dòng)比的確定53.1.2 動(dòng)力參數(shù)計(jì)算63.2 圓錐齒輪的設(shè)計(jì)計(jì)算63.2.1 選擇材料，熱處理方式及精度等級(jí)63.2.2 按齒面接觸疲勞強(qiáng)度設(shè)計(jì)73.2.3計(jì)算齒輪的主要尺寸83.2.4驗(yàn)算輪齒彎曲疲勞強(qiáng)度93.3 軸的設(shè)計(jì)計(jì)算103.3.1軸的設(shè)計(jì)103.3.2 軸的設(shè)計(jì)133.4 葉輪的設(shè)計(jì)163.4.1 結(jié)構(gòu)尺寸設(shè)計(jì)163.4.2 驅(qū)動(dòng)葉輪所需功率L173.5 地輪的構(gòu)造183.6 零件的設(shè)計(jì)計(jì)算183.6.1 絲桿的設(shè)計(jì)183.6.2 鍵連接的選擇及計(jì)算194 使用說(shuō)明書（SM）194.1 使用前注意事項(xiàng)194.2 播種時(shí)應(yīng)注意的事項(xiàng)195 標(biāo)準(zhǔn)化審核報(bào)告（BS）205.1 產(chǎn)品圖樣的審查205.2產(chǎn)品技術(shù)文件的審查205.3 標(biāo)注件的使用情況205.4 審查結(jié)論216 結(jié) 論216.1 機(jī)構(gòu)的創(chuàng)新點(diǎn)216.2 制造價(jià)格及應(yīng)用范圍21參 考 文 獻(xiàn)22致 謝23山西農(nóng)業(yè)大學(xué)工程技術(shù)學(xué)院畢業(yè)設(shè)計(jì)說(shuō)明書1 引 言時(shí)間轉(zhuǎn)瞬即逝，轉(zhuǎn)眼之間四年的大學(xué)生涯就要結(jié)束了，回首四年的學(xué)習(xí)生活，我感到自己的收獲無(wú)比豐富。四年來(lái)，我不僅認(rèn)真學(xué)習(xí)了各門基礎(chǔ)課，而且更加系統(tǒng)地掌握了多門專業(yè)技術(shù)課，在每次的課程設(shè)計(jì)中，我都認(rèn)真對(duì)待，努力鉆研。這樣，通過(guò)四年的鍛煉不斷地提高了我的設(shè)計(jì)、繪圖、識(shí)圖能力?？梢哉f(shuō)，大學(xué)里的理論基礎(chǔ)，不但使我學(xué)會(huì)了分析問(wèn)題、解決問(wèn)題的能力，而且更強(qiáng)化了我的知識(shí)結(jié)構(gòu)。尤其幸運(yùn)的是，我不只一次地深入工廠實(shí)習(xí)，把學(xué)到的知識(shí)應(yīng)用于實(shí)習(xí)現(xiàn)場(chǎng)的具體工作中，提高了自己的動(dòng)手能力，為我今后步入工作崗位打下了更好的實(shí)踐基礎(chǔ)。 本次設(shè)計(jì)的目的是培養(yǎng)自己初步掌握獨(dú)立從事專業(yè)技術(shù)工作的能力，提高自己從事工藝和工藝裝備設(shè)計(jì)的水平，使我初步掌握從事本專業(yè)科學(xué)研究工作的能力。通過(guò)畢業(yè)設(shè)計(jì)不但培養(yǎng)了我運(yùn)用各種工具書的方法和技巧，同時(shí)也培養(yǎng)了我獨(dú)立思考問(wèn)題、解決問(wèn)題的能力。通過(guò)翻閱查找各種工具書，擴(kuò)大了視眼，豐富了自己的知識(shí)范圍。 本次設(shè)計(jì)我是有充分準(zhǔn)備的。我不僅準(zhǔn)備了四年的時(shí)間來(lái)掌握各門專業(yè)課學(xué)習(xí)，而且我多次深入工廠實(shí)習(xí)，更主要的是設(shè)計(jì)期間不斷地從網(wǎng)上、圖書館收集大量的資料，尋找各種解決問(wèn)題的方法。所以說(shuō)本設(shè)計(jì)我是有充分準(zhǔn)備的，它是與生產(chǎn)實(shí)際相結(jié)合。它也將成為我走上工作崗位的一次重要演習(xí)，為我今后的工作打下堅(jiān)實(shí)的基礎(chǔ)。 草坪播種機(jī)設(shè)計(jì)是一個(gè)典型的機(jī)械系統(tǒng)設(shè)計(jì)。 提高農(nóng)業(yè)的機(jī)械化和自動(dòng)化程度，是實(shí)現(xiàn)農(nóng)業(yè)現(xiàn)代化的重要一環(huán)。用現(xiàn)代化設(shè)備裝備我國(guó)農(nóng)業(yè)工廠，已成為一項(xiàng)迫切的重要任務(wù)。 實(shí)現(xiàn)草坪播種作業(yè)機(jī)械化的好處：節(jié)約勞動(dòng)力，提高生產(chǎn)率和草坪質(zhì)量，節(jié)約原材料和降低成本，降低勞動(dòng)強(qiáng)度和改善環(huán)境衛(wèi)生，保證操作的安全，減少草籽的浪費(fèi)等。草坪播種作業(yè)機(jī)械化、自動(dòng)化目前正向著高速化、通用性、可靠性、費(fèi)用低、流水線自動(dòng)化控制、采用新的機(jī)械工具等六個(gè)方向發(fā)展。 2 技術(shù)任務(wù)書（JR）2.1 設(shè)計(jì)的依據(jù)目前在我國(guó)已有專用草坪播種機(jī)械, 但是價(jià)格很高。通常對(duì)于播種面積不算太大, 又不是專業(yè)經(jīng)營(yíng)草坪種植業(yè)的單位或個(gè)人, 就沒(méi)有必要專門買一臺(tái)草坪播種機(jī), 這樣就給草坪播種帶來(lái)很大的困難。為了解決這一問(wèn)題, 經(jīng)過(guò)多次對(duì)市場(chǎng)調(diào)查和研究, 決定設(shè)計(jì)一種簡(jiǎn)易草坪播種機(jī)。2.2 產(chǎn)品的用途及使用范圍草坪是高度培育的特殊草地, 隨著草坪面積的擴(kuò)大, 品質(zhì)的提高, 草坪業(yè)逐漸由單一的人工作業(yè)向半機(jī)械化、機(jī)械化、自動(dòng)化過(guò)渡, 草坪作業(yè)的機(jī)械化已成為十分重要的課題。專用的草坪播種機(jī)還處于起步階段, 草坪草種子細(xì)小,用手撒的方法不僅不易將種子撒勻, 且工作效率低, 不能滿足建坪建設(shè)的要求。 通過(guò)市場(chǎng)調(diào)研，決定設(shè)計(jì)一種由地輪驅(qū)動(dòng)的離心式草坪播種機(jī)，該機(jī)由種子箱、機(jī)架、傳動(dòng)裝置、葉輪等部分組成, 一人即可操作, 播種者雙手推動(dòng)播種機(jī)，種子箱下的旋轉(zhuǎn)葉輪便會(huì)把種子吹出去, 下種口的大小可調(diào), 播種量的多少調(diào)節(jié)下種速度。此播種機(jī)體積小、質(zhì)量輕、結(jié)構(gòu)簡(jiǎn)單、靈活耐用, 不受地形、環(huán)境和氣候的影響, 不僅適用于大面積建坪, 更適用于在復(fù)雜的場(chǎng)地下建坪使用。2.3 主要技術(shù)指標(biāo)和重要技術(shù)參數(shù)計(jì)劃設(shè)計(jì)播種機(jī)的主要設(shè)計(jì)參數(shù)：1） 外形尺寸：519mm380mm800mm2） 功率：417W3） 輪子轉(zhuǎn)速：64r/min4） 力矩：=62224Nmm5） 凈質(zhì)量：40kg6） 變速要求：?jiǎn)渭?jí)7） 葉輪半徑：0.1m2.4 主要工作原理本次設(shè)計(jì)的手推式播種機(jī)主要利用輪子運(yùn)動(dòng)傳動(dòng)變速箱中的錐齒輪實(shí)現(xiàn)飛輪的高速運(yùn)動(dòng)的功能。播種機(jī)工作時(shí)由人推動(dòng)機(jī)器行走，驅(qū)動(dòng)地輪帶動(dòng)安裝在齒輪箱內(nèi)的一對(duì)錐齒輪轉(zhuǎn)動(dòng)，固定在被動(dòng)錐齒輪軸上的葉輪在錐齒輪的驅(qū)動(dòng)下高速旋轉(zhuǎn)。種子箱內(nèi)的種子靠重力通過(guò)種子箱底部的落種口經(jīng)過(guò)絲桿和圓錐下料筒下落到轉(zhuǎn)動(dòng)的葉輪邊緣，在葉輪風(fēng)力的作用下撒布于地表。在被動(dòng)錐齒輪軸伸入種子箱底部的端頭，安裝有攪種裝置，可將種子順利落入撒種盤。撒種量可通過(guò)改變落種口開(kāi)度來(lái)調(diào)節(jié)。2.5 已經(jīng)考慮過(guò)的若干方案的比較我所設(shè)計(jì)的手推式草坪播種機(jī)首先要通過(guò)一個(gè)傳力構(gòu)件將人力傳遞出去。為了讓操作者在正常行走速度下操作，傳遞出去的力應(yīng)通過(guò)增速機(jī)構(gòu)繼續(xù)傳遞。因執(zhí)行播種動(dòng)作的葉輪的相對(duì)運(yùn)動(dòng)方向與人行進(jìn)的方向垂直，經(jīng)前面增速機(jī)構(gòu)傳遞過(guò)來(lái)的運(yùn)動(dòng)都需要再經(jīng)過(guò)一級(jí)轉(zhuǎn)換機(jī)構(gòu)傳遞到執(zhí)行構(gòu)件。通過(guò)分析得到手推式草坪剪草機(jī)的組成框圖，如圖21所示。圖21手推式草坪剪草機(jī)的組成框圖能實(shí)現(xiàn)草坪播種的方法較多，但各有利弊，具體分析如下：（1）用手撒 草坪草種子細(xì)小，用手撒的方法不僅不易將種子撒勻, 且工作效率低, 不能滿足建坪建設(shè)的要求。（2）用鐵篩撒 用鐵篩雖然避免了用手撒的弊端，但浪費(fèi)時(shí)間，且人力消耗量大，不能滿足一般草坪的建設(shè)要求。（3）用播種機(jī) 用播種機(jī)，可避免以上兩種方法存在的問(wèn)題，使所設(shè)計(jì)的機(jī)器小巧，且可靈活操作。因此，我們選擇設(shè)計(jì)手動(dòng)式播種機(jī)。手動(dòng)的形式又有手搖動(dòng)和用手推動(dòng)兩種。機(jī)械容易實(shí)現(xiàn)的是簡(jiǎn)單的轉(zhuǎn)動(dòng)和往復(fù)直線運(yùn)動(dòng)，如果用手搖動(dòng)手柄實(shí)現(xiàn)執(zhí)行構(gòu)件的往復(fù)移動(dòng)，由于播種機(jī)還要靠人力推著向前行進(jìn)，操作者要完成的動(dòng)作過(guò)多，操作不方便。要使操作者只通過(guò)簡(jiǎn)單的操作即可完成播種動(dòng)作，可以用手推播種機(jī)向前行駛，靠播種機(jī)輪子的轉(zhuǎn)動(dòng)將轉(zhuǎn)動(dòng)運(yùn)動(dòng)轉(zhuǎn)變成葉輪的往復(fù)旋轉(zhuǎn)而輸出到執(zhí)行構(gòu)件。顯然設(shè)計(jì)成手動(dòng)式草坪剪草機(jī)是合理而可行的。2.6 關(guān)鍵問(wèn)題及其解決辦法增速機(jī)構(gòu)的設(shè)計(jì)：用組合法實(shí)現(xiàn)增速為了讓操作者在正常行走速度下操作，傳遞出去的力應(yīng)通過(guò)增速機(jī)構(gòu)繼續(xù)傳遞。由于轉(zhuǎn)換機(jī)構(gòu)的運(yùn)動(dòng)輸入構(gòu)件作定軸轉(zhuǎn)動(dòng)，這樣在播種機(jī)動(dòng)力輸入構(gòu)件輪子和轉(zhuǎn)換機(jī)構(gòu)的運(yùn)動(dòng)輸入構(gòu)件之間，可以采用鏈傳動(dòng)，帶傳動(dòng)和齒輪傳動(dòng)。為了使所設(shè)計(jì)的剪草機(jī)結(jié)構(gòu)緊湊，可以采用齒輪傳動(dòng)。而齒輪傳動(dòng)有直齒圓柱齒輪傳動(dòng)，斜齒圓柱齒輪傳動(dòng)，直齒錐齒輪傳動(dòng)和蝸輪蝸桿傳動(dòng)等。但是蝸輪蝸桿傳動(dòng)的效率低，一般是蝸桿主動(dòng)，且軸線空間交錯(cuò)，應(yīng)用到播種機(jī)械中，會(huì)使支撐結(jié)構(gòu)復(fù)雜。直齒圓柱齒輪傳動(dòng)和斜齒圓柱齒輪傳動(dòng)的軸線相互平行，不能起到兩軸垂直的作用，因此，可選擇直齒錐齒輪傳動(dòng)作為增速機(jī)構(gòu)。機(jī)構(gòu)組成方案如圖22所示。 圖2-2 機(jī)構(gòu)簡(jiǎn)圖2.7 機(jī)構(gòu)的功能及特點(diǎn)（1） 該機(jī)采用地輪齒輪傳動(dòng)結(jié)構(gòu)，結(jié)構(gòu)緊湊，體積小，質(zhì)量輕，噪音小、無(wú)污染，使用方便、靈活，適合一般草坪的播種；（2） 無(wú)需引擎驅(qū)動(dòng)，使用安全、可靠，便于維護(hù)；（3） 播種幅寬為1m，外形尺寸（長(zhǎng)寬高：586369200mm）,質(zhì)量40kg（材料由45鋼制作）；（4） 采用耐用的鑄鋁底盤和結(jié)構(gòu)件，具有永不生繡、永不卷曲變形的特點(diǎn)；（5） 地輪半徑為0.25m，且一個(gè)輪子裝上壽命長(zhǎng)的球軸承，使播種機(jī)轉(zhuǎn)彎時(shí)易于推動(dòng)；（6） 金屬手柄易于折疊，以減少包裝尺寸，手柄長(zhǎng)度可伸縮，對(duì)于不同身高的操作者同樣適用；（7） 撒種部分獨(dú)特的設(shè)計(jì)可防止種子堵塞出口通道；（8） 外觀造型美觀，更適合家庭用戶的審美要求；（9） 播種的效果較理想，且成本低，是一般草坪播種的首選產(chǎn)品。 3 設(shè)計(jì)計(jì)算說(shuō)明書 （SS）3.1 草坪播種機(jī)結(jié)構(gòu)的方案設(shè)計(jì)3.1.1 傳動(dòng)比的確定根據(jù)運(yùn)動(dòng)學(xué)基本原理，在忽略種子與撒種盤之間摩擦的情況下，傳動(dòng)比為： （1）式中 Rd-地輪半徑 D-撒種幅寬 r-撒種盤半徑 v-行走速度 H-撒種盤離地高度 g-重力加速度在確定行走速度v時(shí)，既要保證播種機(jī)在種子箱裝滿種子后，播種機(jī)能夠正常作業(yè)，又要保證機(jī)組有較高的作業(yè)生產(chǎn)率，以速度v=6km/h來(lái)設(shè)計(jì)；考慮到我國(guó)一般草坪地塊面積小，幅寬窄的特點(diǎn)，撒種幅寬D設(shè)計(jì)為1m，設(shè)計(jì)參數(shù)Rd=0.25m，r=0.1m，H=0.55m。則按式（1）計(jì)算出地輪驅(qū)動(dòng)離心式播種機(jī)所需的傳動(dòng)比i=3。 3.1.2 動(dòng)力參數(shù)計(jì)算草籽較輕，容易甩出，不需要過(guò)大的載荷，故假設(shè)人的推力為F=250N，所以兩個(gè)地輪上所受力的大小為：F1=F2=125N地輪提供轉(zhuǎn)矩帶動(dòng)撒種盤進(jìn)行機(jī)械運(yùn)動(dòng)，假定撒種盤所受的力全部來(lái)自地輪。則：P輪=Fv=417W地輪轉(zhuǎn)速：n=64r/min 初選8級(jí)精度直齒錐齒輪 滾動(dòng)軸承（球軸承） 齒輪傳動(dòng)軸承（滾子軸承） 傳動(dòng)機(jī)構(gòu)總效率：0.950.9920.98=0.903軸上的所傳遞的功率大小為：=4170.99=413(W)軸上的所傳遞的功率大小為：=4130.950.98=396(W)軸上的轉(zhuǎn)速大小為：=147.69(r/min)軸上的轉(zhuǎn)速大小為：=443.09(r/min)3.2 圓錐齒輪的設(shè)計(jì)計(jì)算圓錐齒輪的設(shè)計(jì)直齒錐齒輪加工多為刨齒，不宜采用硬齒面，計(jì)算步驟如下：3.2.1 選擇材料，熱處理方式及精度等級(jí)（1）齒輪材料。熱處理方式由參考文獻(xiàn)1表6-7和表6-8并考慮HBS1=HBS2+（3050）HBS的要求，小齒輪選用40Cr，調(diào)質(zhì)處理，齒面硬度241286HBS，大齒輪選用42SiMn鋼，調(diào)質(zhì)處理，齒面硬度217255HBS。（2）精度等級(jí)。估計(jì)圓周速度不大于3m/s，根據(jù)參考文獻(xiàn)1表6-5，初選8級(jí)精度。3.2.2 按齒面接觸疲勞強(qiáng)度設(shè)計(jì)1）確定公式中的各參數(shù)值（1）選齒數(shù)。小齒輪齒數(shù)z1=24,z2=uz1=72（2）確定極限應(yīng)力，由參考文獻(xiàn)1圖6-32，按齒面硬度中間值260HBS，查得小齒輪。由參考文獻(xiàn)1圖6-32，按齒面硬度中間值230HBS查得大齒輪。（3）確定壽命系數(shù)ZN。由題意可知：ZN1=ZN2=1。（4）許用應(yīng)力由參考文獻(xiàn)1表6-9查得，SHmin=1。由參考文獻(xiàn)1式（6-20）得 （5）載荷系數(shù)K?？紤]錐齒輪是懸臂布置，由參考文獻(xiàn)1表6-10取K=1.2。（6）計(jì)算小齒輪傳遞的轉(zhuǎn)矩T1 （7）齒寬系數(shù)。取。（8）節(jié)點(diǎn)區(qū)域系數(shù)。（9）確定材料系數(shù)。由參考文獻(xiàn)1表6-11查得。2）計(jì)算和（1）小輪大端分度直徑 （2）小齒輪齒寬中點(diǎn)的分度圓直徑 （3）圓周速度： 故8級(jí)精度合適。3.2.3計(jì)算齒輪的主要尺寸1）模數(shù) 圓整取。2）實(shí)際大端分度圓直徑 3）錐距 4）齒寬 5）分度圓錐角和 ， 6)當(dāng)量齒數(shù) 3.2.4驗(yàn)算輪齒彎曲疲勞強(qiáng)度（1）確定極限應(yīng)力。由參考文獻(xiàn)1圖6-34，按齒面硬度中間值260HBS，查得小齒輪，由參考文獻(xiàn)1圖6-34，按齒面硬度中間值230HBS，查得大齒輪。（2）確定壽命系數(shù)YN1和YN2,由題意可知：YN1 =YN2=1。（3）確定最小安全系數(shù)。查參考文獻(xiàn)1表6-9得。（4）確定許用應(yīng)力。 （5）復(fù)合齒形系數(shù)和。查參考文獻(xiàn)1表6-12得 ，（6）計(jì)算彎曲應(yīng)力： 所以齒輪彎曲強(qiáng)度足夠。3.3 軸的設(shè)計(jì)計(jì)算3.3.1軸的設(shè)計(jì)（1）選擇軸的材料該軸無(wú)特殊要求，選擇45鋼調(diào)質(zhì)處理，=640MPa（2）初步估算軸徑按扭轉(zhuǎn)強(qiáng)度估算輸入端的最小軸徑。按45鋼，取C=116根據(jù)公式，此軸頭上有一鍵槽，將軸徑增大5%，即dmin=（16.341.05）mm=17.15mm,取dmin=18mm（3）軸的結(jié)構(gòu)設(shè)計(jì)1）軸上零件的軸向定位 大齒輪在軸上為對(duì)稱定位，左右兩端靠套筒定位，裝拆，傳力較為簡(jiǎn)單；兩端軸承常用同一尺寸，以便于加工、安裝和維修；為便于拆裝軸承，軸承處軸肩不宜太高。 2）軸上零件的周向定位 齒輪與軸的軸向固定采用普通平鍵聯(lián)接。根據(jù)軸的直徑查得齒輪處的鍵截面尺寸為，配合為，滾動(dòng)軸承內(nèi)圈與軸的配合采用基孔制。 確定各段軸徑和長(zhǎng)度通過(guò)確定定位軸肩高度，從左輪子連接處向右取。 考慮軸的結(jié)構(gòu)工藝性考慮到軸的結(jié)構(gòu)工藝性，在軸的左端和右段均制成倒角 （4）軸的強(qiáng)度演算 經(jīng)結(jié)構(gòu)設(shè)計(jì)之后，各軸段作用力大小和作用點(diǎn)位置、軸承跨距、各段軸徑等參數(shù)均已知。1) 齒輪上作用力的大小轉(zhuǎn)矩：=62224Nmm齒輪端面分度圓直徑： 圓周力：徑向力：軸向力：受力簡(jiǎn)圖5-1所示： 圖3-1垂直面上受力簡(jiǎn)圖2）求垂直面上軸承的支反力及主要截面的彎矩 截面C處的彎矩為：(Nmm)(Nmm) 圖3-2垂直面上截面的彎矩3） 求水平面上軸承的支反力及主要截面的彎矩：截面C處的彎矩為：(Nmm) 圖3-3水平面上截面的支反力4） 截面C處垂直面和水平面的合成彎矩為：(Nmm) (Nmm)圖3-4水平面上截面的彎矩及合成彎矩5）按彎扭合成應(yīng)力校核軸的強(qiáng)度進(jìn)行校核時(shí)，通常只校核軸上承受最大彎矩和扭矩的截面強(qiáng)度，取該截面上的計(jì)算應(yīng)力：通過(guò)查表可知：材料為45鋼，調(diào)質(zhì)處理的許用應(yīng)力為，由于，故安全。3.3.2 軸的設(shè)計(jì)（1）選擇軸的材料該軸無(wú)特殊要求，選擇45鋼調(diào)質(zhì)處理，=640MPa（2）初步估算軸徑按扭轉(zhuǎn)強(qiáng)度估算輸入端的最小軸徑。按45鋼，取C=116根據(jù)公式，此軸頭上有一鍵槽，將軸徑增大5%，即dmin=（11.171.05）mm=11.72mm,取dmin=12mm（3）軸的結(jié)構(gòu)設(shè)計(jì)1）軸上零件的軸向定位 小齒輪在軸上為對(duì)稱定位，上下兩端靠套筒定位，裝拆，傳力較為簡(jiǎn)單；兩端軸承常用同一尺寸，以便于加工、安裝和維修；為便于拆裝軸承，軸承處軸肩不宜太高。 2）軸上零件的周向定位 齒輪與軸的軸向固定采用普通平鍵聯(lián)接。根據(jù)軸的直徑查得齒輪處的鍵截面尺寸為，配合為，滾動(dòng)軸承內(nèi)圈與軸的配合采用基孔制。 確定各段軸徑和長(zhǎng)度通過(guò)確定定位軸肩高度，從上向下取。 考慮軸的結(jié)構(gòu)工藝性考慮到軸的結(jié)構(gòu)工藝性，在軸的左端和右段均制成倒角 （4）軸的強(qiáng)度演算 經(jīng)結(jié)構(gòu)設(shè)計(jì)之后，各軸段作用力大小和作用點(diǎn)位置、軸承跨距、各段軸徑等參數(shù)均已知。2) 齒輪上作用力的大小轉(zhuǎn)矩：=19310.18 Nmm 齒輪端面分度圓直徑： 圓周力：徑向力：軸向力： 圖3-5軸垂直面上受力簡(jiǎn)圖2）求垂直面上軸承的支反力及主要截面的彎矩 截面C處的彎矩為：(Nmm)(Nmm)圖3-6軸垂直面上截面的彎矩3)求水平面上軸承的支反力及主要截面的彎矩：截面C處的彎矩為：(Nmm)圖3-7軸水平面上截面的支反力4)截面C處垂直面和水平面的合成彎矩為：(Nmm) (Nmm)圖3-8軸水平面上截面的彎矩及合成彎矩5)按彎扭合成應(yīng)力校核軸的強(qiáng)度進(jìn)行校核時(shí)，通常只校核軸上承受最大彎矩和扭矩的截面強(qiáng)度，取該截面上的計(jì)算應(yīng)力：通過(guò)查表可知：材料為45鋼，調(diào)質(zhì)處理的許用應(yīng)力為，由于，故安全。3.4 葉輪的設(shè)計(jì)選擇材料：因?yàn)椴葑奄|(zhì)量輕，材料無(wú)特殊要求，選用45號(hào)剛調(diào)質(zhì)處理，葉片厚度1mm，制造上多采用整體鑄造結(jié)構(gòu)和分體鉚接或焊接等工藝方法來(lái)實(shí)現(xiàn)，這也是由其結(jié)構(gòu)特點(diǎn)所決定的。3.4.1 結(jié)構(gòu)尺寸設(shè)計(jì) 圖6-1葉輪形式如圖所示，離心風(fēng)機(jī)的主要結(jié)構(gòu)參數(shù)如下。葉輪外徑, 常用D表示；葉輪寬度, 常用b表示；葉輪出口角,一般用表示。葉輪按葉片出口角的不同可分為三種:前向式葉片彎曲方向與旋轉(zhuǎn)方向相同, 90(90 160)；后向式葉片彎曲方向與旋轉(zhuǎn)方向相反, 90(20 70)；徑向式葉片出口沿徑向安裝,= 90。 根據(jù)播種機(jī)行走速度和撒籽幅寬，初設(shè)葉輪直徑D1=20cm，葉片數(shù)Z按經(jīng)驗(yàn)公式估計(jì)：Z=D1為葉輪外徑，單位厘米。所以葉片數(shù)取6片。葉片傾角 3.4.2 驅(qū)動(dòng)葉輪所需功率L 當(dāng)葉片數(shù)目有限時(shí)，由于流體流動(dòng)方向的變化，葉片理論壓頭公式為： （1）式中：Hth為葉輪壓頭；u為圓周速度；v為徑向速度。飛輪對(duì)氣體作功： （2）式中：k為多變系數(shù)；R為氣體常數(shù)；G為輸送的流體總量；n為多變指數(shù)；TT0為入口全溫；為容積效率。設(shè)葉輪入口處風(fēng)速為v1m=16m/s，=0.75，則入口全溫：由（2）式：3.167(KW)4.22(KW)如果葉輪的效率=0.54，則軸功率：Ls=Lt/0.54=7.81(KW)由,得293K時(shí)氣體重度，故驅(qū)動(dòng)葉輪所需軸功率L為：0.3338(KW)，故符合設(shè)計(jì)功率。3.5 地輪的構(gòu)造 地輪由兩個(gè)個(gè)直徑為50cm 的小車輪及其連桿組成。兩個(gè)地輪是由長(zhǎng)軸的兩端按軸的垂直方向各焊有一對(duì)長(zhǎng)13cm的平行小鐵板來(lái)固定, 小鐵板下端有固定行走輪軸的陷口, 使地輪固定。長(zhǎng)軸被套在大三角鐵后面的兩個(gè)寬鐵環(huán)內(nèi), 長(zhǎng)軸上設(shè)有凸出物使得長(zhǎng)軸在寬鐵環(huán)內(nèi)只能轉(zhuǎn)動(dòng), 不能左右串動(dòng)。在長(zhǎng)軸的中間, 對(duì)準(zhǔn)雙桿手柄的一個(gè)級(jí)桿處, 在長(zhǎng)軸上焊有一個(gè)長(zhǎng)75cm 的單鐵桿柄, 其方向與長(zhǎng)軸兩端的兩平行小鐵板恰好反方向，使人推上播種機(jī)能夠順利行走。3.6 零件的設(shè)計(jì)計(jì)算在該播種機(jī)上所用的一些附件都是一些標(biāo)準(zhǔn)件，它們一共有絲桿、鍵和墊圈。3.6.1 絲桿的設(shè)計(jì)此絲桿受力不大，無(wú)特殊要求，選用45號(hào)鋼。熱處理：調(diào)質(zhì)HB220-270，高頻淬火HRC45-48。因?yàn)榻z桿直徑已經(jīng)標(biāo)準(zhǔn)化，所以在設(shè)計(jì)絲桿時(shí)，直徑不能任意確定。我國(guó)所規(guī)定的絲桿直徑系列為：30，45，65，（85）90，（115）120，150，200。一般情況下，確定的絲桿直徑應(yīng)符合此系列。故，選用絲桿直徑為30mm。螺旋角：物料為草籽，選用=30絲桿螺槽深度：h=0.2D=6mm絲桿與套筒間隙的確定：=（0.003-0.005）D，取=0.005D=0.15mm3.6.2 鍵連接的選擇及計(jì)算中間軸和齒輪用鍵聯(lián)接的選擇和強(qiáng)度校核 齒輪與軸的鍵聯(lián)接 選用圓頭普通平鍵（型）按軸徑d=20mm及輪廓長(zhǎng)l=78mm,查表14-1,選鍵1870GB1096-79.強(qiáng)度校核 鍵材料用45鋼，查表得許用應(yīng)力，鍵的工作長(zhǎng)度，按公式得擠壓應(yīng)力：雖然略大于，但齒輪與軸是采用過(guò)盈配合，靠聯(lián)接擦力傳遞部分轉(zhuǎn)矩，故聯(lián)接的強(qiáng)度是足夠的。4 使用說(shuō)明書（SM）4.1 使用前注意事項(xiàng)播種機(jī)在路上行走時(shí)， 可將離合器拉起,，使被動(dòng)軸與主動(dòng)軸分開(kāi)，只有兩個(gè)地輪著地，這樣便于遠(yuǎn)距離和播過(guò)種的區(qū)域的行走。如果需要播種，在被播地段上，將離合器拉下，兩軸自然結(jié)合，然后開(kāi)始播種。如果播種籽量不適宜，可調(diào)節(jié)下種口大小，在小范圍內(nèi)調(diào)整播種量。播種后出苗特征為：苗幅寬為4cm 左右，兩苗幅間寬為56cm 左右，這樣出苗后24 個(gè)月便可長(zhǎng)滿苗幅間空處。4.2 播種時(shí)應(yīng)注意的事項(xiàng)（1）草坪床應(yīng)疏松，表層不能有過(guò)大的石塊或大的硬土塊及其他草根類雜物。（2）草坪床應(yīng)該盡量平整，坡度不能過(guò)大。5 標(biāo)準(zhǔn)化審核報(bào)告（BS）5.1 產(chǎn)品圖樣的審查手推式草坪播種機(jī)的傳動(dòng)裝置和葉輪風(fēng)扇的設(shè)計(jì)已經(jīng)基本完成，現(xiàn)以具備全套圖紙和一線基本數(shù)據(jù)，根據(jù)有關(guān)規(guī)定，對(duì)其進(jìn)行標(biāo)注化審查，結(jié)果如下： （1） 產(chǎn)品的圖樣完整、統(tǒng)一、表達(dá)準(zhǔn)確清楚、圖樣清楚。符合GB4440-84、GB-83機(jī)械制圖的規(guī)定。（2） 產(chǎn)品圖樣公差與配合的選擇與標(biāo)準(zhǔn)符合GB/T1800、3-1998的規(guī)定。（3） 產(chǎn)品圖樣的編號(hào)符合JB/T5054.5-2000中華人民共和國(guó)機(jī)械行業(yè)標(biāo)準(zhǔn)產(chǎn)品圖樣及設(shè)計(jì)的完整性。（4） 圖紙的標(biāo)題欄與明細(xì)欄符合GB/T10609. 1-1989GB/T10690. 2-1989的規(guī)定。（5） 產(chǎn)品圖樣粗糙度的標(biāo)注符合GB131-83表面特征代號(hào)及注法的規(guī)定。（6） 產(chǎn)品圖樣焊縫的代號(hào)符合GB324-80焊縫代號(hào)的規(guī)定。5.2 產(chǎn)品技術(shù)文件的審查（1） 產(chǎn)品的技術(shù)文件名稱、術(shù)語(yǔ)符合ZB/TJ01和0351-90產(chǎn)品圖樣及設(shè)計(jì)文件術(shù)語(yǔ)及有關(guān)標(biāo)準(zhǔn)的規(guī)定。（2） 量和單位符合GB3100GB3102-93的規(guī)定。（3）技術(shù)文件所用的編碼符合JB/T8823-1998機(jī)械工業(yè)企業(yè)計(jì)算機(jī)輔助管理信息分類編碼導(dǎo)則的規(guī)定。（4）技術(shù)文件的完整性符合JB/T5054.5-2000產(chǎn)品圖樣及技術(shù)文件完整性的規(guī)定及農(nóng)機(jī)部門的有關(guān)具體要求。5.3 標(biāo)注件的使用情況本設(shè)計(jì)所用的緊固件均采用標(biāo)準(zhǔn)的螺栓，材料及材料代號(hào)也符合國(guó)家標(biāo)準(zhǔn)和部頒標(biāo)準(zhǔn)的相關(guān)規(guī)定。5.4 審查結(jié)論經(jīng)過(guò)對(duì)播種機(jī)裝置和傳動(dòng)設(shè)計(jì)的標(biāo)準(zhǔn)化審查，認(rèn)為該設(shè)計(jì)基本貫徹了國(guó)家最新頒發(fā)的各種標(biāo)準(zhǔn)，圖紙和設(shè)計(jì)文件完整齊全，符合標(biāo)準(zhǔn)化得要求。6 結(jié) 論6.1 機(jī)構(gòu)的創(chuàng)新點(diǎn)（1） 從機(jī)構(gòu)運(yùn)動(dòng)的功能出發(fā)，按變異組合法和類比法完成機(jī)構(gòu)的構(gòu)件和設(shè)計(jì);（2） 在作品樣機(jī)加工前，使用三維造型軟件進(jìn)行三維造型、虛擬裝配和運(yùn)動(dòng)仿真，從理論上驗(yàn)證設(shè)計(jì)的可行性，然后進(jìn)行樣機(jī)制作；（3） 無(wú)引擎驅(qū)動(dòng)，節(jié)省能源，無(wú)污染（噪音、廢氣），采用綠色環(huán)保設(shè)計(jì)；（4） 外觀造型新穎，推桿可折疊伸縮，適合家庭用戶使用；（5） 采用齒輪機(jī)構(gòu)（實(shí)現(xiàn)增速），提高整機(jī)的工作效率，解決了手動(dòng)播種機(jī)工作效率不高的問(wèn)題；（6） 產(chǎn)品成本（制造和使用成本）低，符合廣大用戶購(gòu)買能力的要求。6.2 制造價(jià)格及應(yīng)用范圍根據(jù)目前市場(chǎng)實(shí)際:：制造原材料費(fèi)用80120 元，手工費(fèi): 6080 元，因此總造價(jià)在200元以內(nèi)。目前使用于我國(guó)大部分地區(qū)的一般建坪。參 考 文 獻(xiàn)1 吳偉，任紅英. 機(jī)械設(shè)計(jì)教程 M . 北京：北京理工大學(xué)出版社，2007.2 張祖立. 機(jī)械設(shè)計(jì) M . 北京：中國(guó)農(nóng)業(yè)出版社，2004.3 吳宗澤，羅圣國(guó). 機(jī)械設(shè)計(jì)課程設(shè)計(jì)手冊(cè)（第3版）M.北京：高等教育出版社，2006.4 張也影. 流體力學(xué)（第2版）M . 北京：高等教育出版社，2005.5 張良成. 材料力學(xué) M . 北京：中國(guó)農(nóng)業(yè)出版社，20036 楊敏麗. 牧草生產(chǎn)機(jī)械化:西部農(nóng)業(yè)機(jī)械化發(fā)展J中國(guó)農(nóng)機(jī)化, 2000,(04)7 楊愛(ài)軍. 呼和浩特市地區(qū)農(nóng)業(yè)機(jī)械化現(xiàn)狀及發(fā)展對(duì)策J農(nóng)村機(jī)械化, 2004,(04)8 趙嶺,呂釗欽. 可靠性技術(shù)在農(nóng)業(yè)機(jī)械中的應(yīng)用J山東農(nóng)機(jī), 2004,(07)9 郭毅, 張祖立, 張旭東. 大蒜播種機(jī)械的研究現(xiàn)狀J. 農(nóng)機(jī)化研究, 2009, (06)10 高林. 育苗生產(chǎn)線氣吸式播種系統(tǒng)智能控制的研究D北京林業(yè)大學(xué), 2008 . 11 劉文忠. 氣吸式排種裝置排種性能試驗(yàn)研究D內(nèi)蒙古農(nóng)業(yè)大學(xué), 2008 .12 李濟(jì)賓. 播種機(jī)組行走的方法J. 河南農(nóng)業(yè), 1993, (04) 13 籍增順. 關(guān)于發(fā)展小雜糧的思考J. 山西農(nóng)業(yè)(村委主任), 2009, (04)14 夏俊芬. 旱作多功能精密穴播輪的研究D華中農(nóng)業(yè)大學(xué), 200015 史智興. 精播機(jī)排種性能檢測(cè)系統(tǒng)及關(guān)鍵技術(shù)研究D中國(guó)農(nóng)業(yè)大學(xué), 200216 濮良貴，紀(jì)名剛機(jī)械設(shè)計(jì)（第七版）S北京：高等教育出版社2001致 謝在設(shè)計(jì)過(guò)程中，得到了崔清亮老師的親切關(guān)懷和耐心的指導(dǎo)。崔老師多次詢問(wèn)研究進(jìn)程，并為我指點(diǎn)迷津，幫助我開(kāi)拓研究思路，精心點(diǎn)撥、熱忱鼓勵(lì)。崔老師一絲不茍的作風(fēng)，嚴(yán)謹(jǐn)求實(shí)的態(tài)度，踏踏實(shí)實(shí)的精神，不僅授我以文，而且教我做人，雖歷時(shí)半年，卻給以終生受益無(wú)窮之道。在次，我向崔老師表示忠心的感謝！我還非常感謝工程技術(shù)學(xué)院的老師們，在四年學(xué)習(xí)期間，他們不僅教給了我很多知識(shí)，使我從對(duì)機(jī)械一無(wú)所知成為具有初步機(jī)械學(xué)知識(shí)并且可以簡(jiǎn)單應(yīng)用的人，從只為自己的事情操心變成現(xiàn)在經(jīng)常看報(bào)紙，聽(tīng)廣播，并關(guān)注國(guó)家大事，而且還教給了我做人的道理。對(duì)此我非常感謝！最后，由草坪播種機(jī)的復(fù)雜性和長(zhǎng)期性，不是用一篇文章就能解決問(wèn)題的，另外，由于我的經(jīng)驗(yàn)匱乏、水平有限，本文錯(cuò)誤和疏漏之處不少，請(qǐng)老師和同學(xué)們指正，謝謝！- 23 -山 西 農(nóng) 業(yè) 大 學(xué)本科生畢業(yè)論文（設(shè)計(jì)）選題審批表畢業(yè)論文（設(shè)計(jì)）題目草坪播種機(jī)的設(shè)計(jì)指 導(dǎo) 教 師崔清亮職 稱教 授學(xué)生具備條件修完教學(xué)計(jì)劃要求課程內(nèi)容及學(xué)時(shí)選題完成形式開(kāi)題報(bào)告內(nèi) 容 簡(jiǎn) 要：本設(shè)計(jì)是根據(jù)國(guó)內(nèi)外播種機(jī)的發(fā)展趨勢(shì)，通用性和適應(yīng)性不斷提高以及本著結(jié)構(gòu)簡(jiǎn)單操作靈活的原則，而設(shè)計(jì)的一種由地輪驅(qū)動(dòng)的離心式草坪播種機(jī)。該機(jī)結(jié)構(gòu)上優(yōu)點(diǎn)，使之能適應(yīng)各種草地的播種。小到1-2分大的草地，大到十幾畝的草地都能適應(yīng)。還可以根據(jù)草地的不同情況，調(diào)節(jié)合適的播種量。該播種機(jī)無(wú)引擎驅(qū)動(dòng)，無(wú)噪音污染，播種效率高，輕便簡(jiǎn)潔，操作方便，美觀實(shí)用，適用于一般草坪的播種。本文著重對(duì)播種機(jī)增速器、撒種部分以及葉輪等結(jié)構(gòu)進(jìn)行設(shè)計(jì)選擇。 系主任簽字： 年 月 日 院長(zhǎng)簽字： 年 月 日2山西農(nóng)業(yè)大學(xué)本科生畢業(yè)設(shè)計(jì)開(kāi)題報(bào)告題 目 草坪播種機(jī)的設(shè)計(jì) 學(xué)院名稱 信息學(xué)院 專業(yè)名稱 機(jī)械設(shè)計(jì)制造及其自動(dòng)化年 級(jí) 2005級(jí) 學(xué)生姓名 胡艷虹 學(xué) 號(hào) 2005151215 指導(dǎo)教師 崔清亮 職 稱 教 授 2009年 3 月 25 日選題的依據(jù)及意義（包括課題的理論價(jià)值和實(shí)踐價(jià)值；國(guó)內(nèi)外的研究概況等）：目前在我國(guó)已有專用草坪播種機(jī)械, 但是價(jià)格很高。通常對(duì)于播種面積不算太大, 又不是專業(yè)經(jīng)營(yíng)草坪種植業(yè)的單位或個(gè)人, 就沒(méi)有必要專門買一臺(tái)草坪播種機(jī), 這樣就給草坪播種帶來(lái)很大的困難。為了解決這一問(wèn)題, 經(jīng)過(guò)多次對(duì)市場(chǎng)調(diào)查和研究, 決定設(shè)計(jì)一種簡(jiǎn)易草坪播種機(jī)。草坪是高度培育的特殊草地, 隨著草坪面積的擴(kuò)大, 品質(zhì)的提高, 草坪業(yè)逐漸由單一的人工作業(yè)向半機(jī)械化、機(jī)械化、自動(dòng)化過(guò)渡, 草坪作業(yè)的機(jī)械化已成為十分重要的課題。專用的草坪播種機(jī)還處于起步階段, 草坪草種子細(xì)小,用手撒的方法不僅不易將種子撒勻, 且工作效率低, 不能滿足建坪建設(shè)的要求。 通過(guò)市場(chǎng)調(diào)研，決定設(shè)計(jì)一種由地輪驅(qū)動(dòng)的離心式草坪播種機(jī)，該機(jī)由種子箱、機(jī)架、傳動(dòng)裝置、葉輪等部分組成, 一人即可操作, 播種者雙手推動(dòng)播種機(jī)，種子箱下的旋轉(zhuǎn)葉輪便會(huì)把種子吹出去, 下種口的大小可調(diào), 播種量的多少調(diào)節(jié)下種速度。此播種機(jī)體積小、質(zhì)量輕、結(jié)構(gòu)簡(jiǎn)單、靈活耐用, 不受地形、環(huán)境和氣候的影響, 不僅適用于大面積建坪, 更適用于在復(fù)雜的場(chǎng)地下建坪使用。本課題研究?jī)?nèi)容 本設(shè)計(jì)研究的草坪播種機(jī)是一種由地輪驅(qū)動(dòng)的離心式草坪播種機(jī)，該機(jī)由種子箱、機(jī)架、傳動(dòng)裝置、葉輪等部分組成, 一人即可操作, 播種者雙手推動(dòng)播種機(jī)，種子箱下的旋轉(zhuǎn)葉輪便會(huì)把種子吹出去, 下種口的大小可調(diào), 播種量的多少調(diào)節(jié)下種速度。此播種機(jī)體積小、質(zhì)量輕、結(jié)構(gòu)簡(jiǎn)單、靈活耐用, 不受地形、環(huán)境和氣候的影響, 不僅適用于大面積建坪, 更適用于在復(fù)雜的場(chǎng)地下建坪使用。本課題研究方案能實(shí)現(xiàn)草坪播種的方法較多，但各有利弊，具體分析如下：（1）用手撒 草坪草種子細(xì)小，用手撒的方法不僅不易將種子撒勻, 且工作效率低, 不能滿足建坪建設(shè)的要求。（2）用鐵篩撒 用鐵篩雖然避免了用手撒的弊端，但浪費(fèi)時(shí)間，且人力消耗量大，不能滿足一般草坪的建設(shè)要求。（3）用播種機(jī) 用播種機(jī)，可避免以上兩種方法存在的問(wèn)題，使所設(shè)計(jì)的機(jī)器小巧，且可靈活操作。因此，我們選擇設(shè)計(jì)手動(dòng)式播種機(jī)。研究的創(chuàng)新之處（1） 無(wú)引擎驅(qū)動(dòng)，節(jié)省能源，無(wú)污染（噪音、廢氣），采用綠色環(huán)保設(shè)計(jì)；（2） 外觀造型新穎，推桿可折疊伸縮，適合家庭用戶使用；（3） 采用齒輪機(jī)構(gòu)（實(shí)現(xiàn)增速），提高整機(jī)的工作效率，解決了手動(dòng)播種機(jī)工作效率不高的問(wèn)題；（4） 產(chǎn)品成本（制造和使用成本）低，符合廣大用戶購(gòu)買能力的要求。 研究過(guò)程(含完成期限)第一周與指導(dǎo)老師確定設(shè)計(jì)題目并制定詳細(xì)的設(shè)計(jì)要求；第二周調(diào)查、收集、研究現(xiàn)有資料，根據(jù)課題計(jì)劃任務(wù)書的要求，明確整個(gè)設(shè)計(jì)的任務(wù)和方向；第三周提出多種設(shè)計(jì)方案，通過(guò)分析對(duì)比，確定出最優(yōu)方案；第四和第五周以確定的初步方案繪制出原理圖或機(jī)構(gòu)運(yùn)動(dòng)簡(jiǎn)圖，確定機(jī)構(gòu)組成和各種參數(shù)計(jì)算；第六和第七周詳細(xì)繪制總裝配圖、部件裝配圖和零件圖；第八周交由指導(dǎo)老師批改；第九周修改并完善設(shè)計(jì)指導(dǎo)教師意見(jiàn) 指導(dǎo)教師簽名：年 月 日教研室意見(jiàn) 教研室主任簽名：年 月 日院系意見(jiàn) 主管領(lǐng)導(dǎo)簽名： 年 月 日Design of machine and machine elementsMachine designMachine design is the art of planning or devising new or improved machines to accomplish specific purposes. In general, a machine will consist of a combination of several different mechanical elements properly designed and arranged to work together, as a whole. During the initial planning of a machine, fundamental decisions must be made concerning loading, type of kinematic elements to be used, and correct utilization of the properties of engineering materials. Economic considerations are usually of prime importance when the design of new machinery is undertaken. In general, the lowest over-all costs are designed. Consideration should be given not only to the cost of design, manufacture the necessary safety features and be of pleasing external appearance. The objective is to produce a machine which is not only sufficiently rugged to function properly for a reasonable life, but is at the same time cheap enough to be economically feasible. The engineer in charge of the design of a machine should not only have adequate technical training, but must be a man of sound judgment and wide experience, qualities which are usually acquired only after considerable time has been spent in actual professional work.Design of machine elements The principles of design are, of course, universal. The same theory or equations may be applied to a very small part, as in an instrument, or, to a larger but similar part used in a piece of heavy equipment. In no ease, however, should mathematical calculations be looked upon as absolute and final. They are all subject to the accuracy of the various assumptions, which must necessarily be made in engineering work. Sometimes only a portion of the total number of parts in a machine are designed on the basis of analytic calculations. The form and size of the remaining parts are designed on the basis of analytic calculations. On the other hand, if the machine is very expensive, or if weight is a factor, as in airplanes, design computations may then be made for almost all the parts. The purpose of the design calculations is, of course, to attempt to predict the stress or deformation in the part in order that it may sagely carry the loads, which will be imposed on it, and that it may last for the expected life of the machine. All calculations are, of course, dependent on the physical properties of the construction materials as determined by laboratory tests. A rational method of design attempts to take the results of relatively simple and fundamental tests such as tension, compression, torsion, and fatigue and apply them to all the complicated and involved situations encountered in present-day machinery. In addition, it has been amply proved that such details as surface condition, fillets, notches, manufacturing tolerances, and heat treatment have a market effect on the strength and useful life of a machine part. The design and drafting departments must specify completely all such particulars, must specify completely all such particulars, and thus exercise the necessary close control over the finished product. As mentioned above, machine design is a vast field of engineering technology. As such, it begins with the conception of an idea and follows through the various phases of design analysis, manufacturing, marketing and consumerism. The following is a list of the major areas of consideration in the general field of machine design: Initial design conception; Strength analysis; Materials selection; Appearance; Manufacturing; Safety; Environment effects; Reliability and life; Strength is a measure of the ability to resist, without fails, forces which cause stresses and strains. The forces may be; Gradually applied; Suddenly applied; Applied under impact; Applied with continuous direction reversals; Applied at low or elevated temperatures. If a critical part of a machine fails, the whole machine must be shut down until a repair is made. Thus, when designing a new machine, it is extremely important that critical parts be made strong enough to prevent failure. The designer should determine as precisely as possible the nature, magnitude, direction and point of application of all forces. Machine design is mot, however, an exact science and it is, therefore, rarely possible to determine exactly all the applied forces. In addition, different samples of a specified material will exhibit somewhat different abilities to resist loads, temperatures and other environment conditions. In spite of this, design calculations based on appropriate assumptions are invaluable in the proper design of machine. Moreover, it is absolutely essential that a design engineer knows how and why parts fail so that reliable machines which require minimum maintenance can be designed. Sometimes, a failure can be serious, such as when a tire blows out on an automobile traveling at high speeds. On the other hand, a failure may be no more than a nuisance. An example is the loosening of the radiator hose in the automobile cooling system. The consequence of this latter failure is usually the loss of some radiator coolant, a condition which is readily detected and corrected. The type of load a part absorbs is just as significant as the magnitude. Generally speaking, dynamic loads with direction reversals cause greater difficulties than static loads and, therefore, fatigue strength must be considered. Another concern is whether the material is ductile or brittle. For example, brittle materials are considered to be unacceptable where fatigue is involved. In general, the design engineer must consider all possible modes of failure, which include the following: Stress; Deformation; Wear; Corrosion; Vibration; Environmental damage; Loosening of fastening devices. The part sizes and shapes selected must also take into account many dimensional factors which produce external load effects such as geometric discontinuities, residual stresses due to forming of desired contours, and the application of interference fit joint. Selected from” design of machine elements”, 6th edition, m. f. sports, prentice-hall, inc., 1985 and “machine design”, Anthony Esposito, charles e., Merrill publishing company, 1975.Mechanical properties of materials The material properties can be classified into three major headings: (1) physical, (2) chemical, (3) mechanicalPhysical properties Density or specific gravity, moisture content, etc., can be classified under this category. Chemical propertiesMany chemical properties come under this category. These include acidity or alkalinity, react6ivity and corrosion. The most important of these is corrosion which can be explained in laymans terms as the resistance of the material to decay while in continuous use in a particular atmosphere. Mechanical properties Mechanical properties include in the strength properties like tensile, compression, shear, torsion, impact, fatigue and creep. The tensile strength of a material is obtained by dividing the maximum load, which the specimen bears by the area of cross-section of the specimen. This is a curve plotted between the stress along the This is a curve plotted between the stress along the Y-axis(ordinate) and the strain along the X-axis (abscissa) in a tensile test. A material tends to change or changes its dimensions when it is loaded, depending upon the magnitude of the load. When the load is removed it can be seen that the deformation disappears. For many materials this occurs op to a certain value of the stress called the elastic limit Ap. This is depicted by the straight line relationship and a small deviation thereafter, in the stress-strain curve (fig.3.1). Within the elastic range, the limiting value of the stress up to which the stress and strain are proportional, is called the limit of proportionality Ap. In this region, the metal obeys hookess law, which states that the stress is proportional to strain in the elastic range of loading, (the material completely regains its original dimensions after the load is removed). In the actual plotting of the curve, the proportionality limit is obtained at a slightly lower value of the load than the elastic limit. This may be attributed to the time-lagin the regaining of the original dimensions of the material. This effect is very frequently noticed in some non-ferrous metals. Which iron and nickel exhibit clear ranges of elasticity, copper, zinc, tin, are found to be imperfectly elastic even at relatively low values low values of stresses. Actually the elastic limit is distinguishable from the proportionality limit more clearly depending upon the sensitivity of the measuring instrument. When the load is increased beyond the elastic limit, plastic deformation starts. Simultaneously the specimen gets work-hardened. A point is reached when the deformation starts to occur more rapidly than the increasing load. This point is called they yield point Q. the metal which was resisting the load till then, starts to deform somewhat rapidly, i. e., yield. The yield stress is called yield limit Ay. The elongation of the specimen continues from Q to S and then to T. The stress-strain relation in this plastic flow period is indicated by the portion QRST of the curve. At the specimen breaks, and this load is called the breaking load. The value of the maximum load S divided by the original cross-sectional area of the specimen is referred to as the ultimate tensile strength of the metal or simply the tensile strength Au. Logically speaking, once the elastic limit is exceeded, the metal should start to yield, and finally break, without any increase in the value of stress. But the curve records an increased stress even after the elastic limit is exceeded. Two reasons can be given for this behavior: The strain hardening of the material; The diminishing cross-sectional area of the specimen, suffered on account of the plastic deformation. The more plastic deformation the metal undergoes, the harder it becomes, due to work-hardening. The more the metal gets elongated the more its diameter (and hence, cross-sectional area) is decreased. This continues until the point S is reached. After S, the rate at which the reduction in area takes place, exceeds the rate at which the stress increases. Strain becomes so high that the reduction in area begins to produce a localized effect at some point. This is called necking. Reduction in cross-sectional area takes place very rapidly; so rapidly that the load value actually drops. This is indicated by ST. failure occurs at this point T. Then percentage elongation A and reduction in reduction in area W indicate the ductility or plasticity of the material: A=(L-L0)/L0*100% W=(A0-A)/A0*100% Where L0 and L are the original and the final length of the specimen; A0 and A are the original and the final cross-section area. Selected from “testing of metallic materials”Quality assurance and control Product quality is of paramount importance in manufacturing. If quality is allowed deteriorate, then a manufacturer will soon find sales dropping off followed by a possible business failure. Customers expect quality in the products they buy, and if a manufacturer expects to establish and maintain a name in the business, quality control and assurance functions must be established and maintained before, throughout, and after the production process. Generally speaking, quality assurance encompasses all activities aimed at maintaining quality, including quality control. Quality assurance can be divided into three major areas. These include the following:Source and receiving inspection before manufacturing;In-process quality control during manufacturing;Quality assurance after manufacturing. Quality control after manufacture includes warranties and product service extended to the users of the product.Source and receiving inspection before manufacturing Quality assurance often begins ling before any actual manufacturing takes place. This may be done through source inspections conducted at the plants that supply materials, discrete parts, or subassemblies to manufacturer. The manufacturers source inspector travels to the supplier factory and inspects raw material or premanufactured parts and assemblies. Source inspections present an opportunity for the manufacturer to sort out and reject raw materials or parts before they are shipped to the manufacturers production facility. The responsibility of the source inspector is to check materials and parts against design specifications and to reject the item if specifications are not met. Source inspections may include many of the same inspections that will be used during production. Included in these are:Visual inspection;Metallurgical testing;Dimensional inspection;Destructive and nondestructive inspection;Performance inspection.Visual inspections Visual inspections examine a product or material for such specifications as color, texture, surface finish, or overall appearance of an assembly to determine if there are any obvious deletions of major parts or hardware.Metallurgical testing Metallurgical testing is often an important part of source inspection, especially if the primary raw material for manufacturing is stock metal such as bar stock or structural materials. Metals testing can involve all the major types of inspections including visual, chemical, spectrographic, and mechanical, which include hardness, tensile, shear, compression, and spectr5ographic analysis for alloy content. Metallurgical testing can be either destructive or nondestructive.Dimensional inspection Few areas of quality control are as important in manufactured products as dimensional requirements. Dimensions are as important in source inspection as they are in the manufacturing process. This is especially critical if the source supplies parts for an assembly. Dimensions are inspected at the source factory using standard measuring tools plus special fit, form, and function gages that may required. Meeting dimensional specifications is critical to interchangeability of manufactured parts and to the successful assembly of many parts into complex assemblies such as autos, ships, aircraft, and other multipart products.Destructive and nondestructive inspection In some cases it may be necessary for the source inspections to call for destructive or nondestructive tests on raw materials or p0arts and assemblies. This is particularly true when large amounts of stock raw materials are involved. For example it may be necessary to inspect castings for flaws by radiographic, magnetic particle, or dye penetrant techniques before they are shipped to the manufacturer for final machining. Specifications calling for burn-in time for electronics or endurance run tests for mechanical components are further examples of nondestructive tests. It is sometimes necessary to test material and parts to destruction, but because of the costs and time involved destructive testing is avoided whenever possible. Examples include pressure tests to determine if safety factors are adequate in the design. Destructive tests are probably more frequent in the testing of prototype designs than in routine inspection of raw material or parts. Once design specifications are known to be met in regard to the strength of materials, it is often not necessary to test further parts to destruction unless they are genuinely suspect.Performance inspection Performance inspections involve checking the function of assemblies, especially those of complex mechanical systems, prior to installation in other products. Examples include electronic equipment subcomponents, aircraft and auto engines, pumps, valves, and other mechanical systems requiring performance evaluation prior to their shipment and final installation. Selected form “modern materials and manufacturing process”Electro-hydraulic drum brakesApplication The YWW series electro-hydraulic brake is a normally closed brake, suitable for horizontal mounting. It is mainly used in portal cranes, bucket stacker/reclaimersslewing mechanism.The YKW series electro-hydraulic brake is a normally opened brake, suitable for horizontal mounting, employing a thruster as actuator. with the foot controlling switch the operator can release or close the brake. It is mainly used for deceleration braking of portal cranesslewing mechanism. In a non-operating state the machinery can be braked by a manual close device.The RKW series brake is a normally opened brake, which is operated by foot driven hydraulic pump, suitable for horizontal mounting. Mainly used in the slewing mechanism of middle and small portal cranes. When needed, the brake is activated by a manual closed device. Main design featuresInterlocking shoes balancing devices (patented technology) constantly equalizes the clearance of brake shoes on both sides and made adjustment unnecessary, thus avoiding one side of the brake lining sticking to the brake wheel. The brake is equipped with a shoed autoaligning device.Main hinge points are equipped with self-lubricating bearing, making high efficiency of transmission, long service life. Lubricating is unnecessary during operation.Adjustable bracket ensure the brake works well.The brake spring is arranged inside a square tube and a surveyors rod is placed on one side. It is easy to read braking torque value and avoid measuring and computing.Brake lining is of card whole-piece shaping structure, easy to replace. Brake linings of various materials such as half-metal (non-asbestos) hard and half-hard, soft (including asbestos) substance are available for customers to choose.All adopt the companys new types of thruster as corollary equipment which work accurately and have long life. Hydraulic Power TransmissionThe Two Types Of Power Transmission In hydraulic power transmission the apparatus (pump) used for conversion of the mechanical (or electrical,thermal) energy to hydraulic energy is arranged on the input of the kinematic chain ,and the apparatus (motor) used for conversion of the hydraulic energy to mechanical energy is arranged on the output (fig.2-1) The theoretical design of the energy converters depends on the component of the bernouilli equation to be used for hydraulic power transmission. In systerms where, mainly, hydrostatic pressure is utilized, displacement (hydrostatic) pumps and motors are used, while in those where the hydrodynamic pressure is utilized is utilized gor power transmission hydrodynamic energy converters (e.g. centrifugal pumps) are used. The specific characteristic of the energy converters is the weight required for transmission of unit power. It can be demonstrated that the use of hydrostatic energy converters for the low and medium powers, and of hydrodynamic energy converters of high power are more favorite (fig.2-2). This is the main reason why hydrostatic energy converters are used in industrial apparatus. transformation of the energy in hydraulic transmission. 1. driving motor (electric, diesel engine);2. mechanical energy;3. pump; 4. hydraulic energy; 5. hydraulic motor; 6. mechanical energy; 7. load variation of the mass per unit power in hydrostatic and hydrodynamic energy converters 1、hydrostatic; 2.hydrodynamicOnly displacement energy converters are dealt with in the following. The elements performing converters provide one or several size. Expansion of the working chambers in a pump is produced by the external energy admitted, and in the motor by the hydraulic energy. Inflow of the fluid occurs during expansion of the working chamber, while the outflow (displacement) is realized during contraction. Such devices are