機械原理課程設(shè)計(臺式電風(fēng)扇的搖頭裝置)

目錄1．臺式電風(fēng)扇搖頭裝置的功能與設(shè)計要求·································31.1工作原理及工藝過程················································31.2功能分解··························································31.3原始數(shù)據(jù)及設(shè)計要求················································31.3.1原始數(shù)據(jù)·····················································1.3.2設(shè)計要求·····················································1.4設(shè)計任務(wù)··························································32．執(zhí)行機構(gòu)的設(shè)計·····················································42.1〔方案Ⅰ〕··························································42.2〔方案Ⅱ〕··························································42.3〔方案Ⅲ〕··························································52.4〔方案Ⅳ〕··························································63．執(zhí)行機構(gòu)的輔助構(gòu)件設(shè)計············································63.1滑銷控制機構(gòu)〔方案Ⅰ〕············································63.2齒輪控制機構(gòu)〔方案Ⅱ〕··············································74．減速機構(gòu)的設(shè)計·····················································74.1蝸桿減速機構(gòu)〔方案Ⅰ〕··············································74.2錐齒輪減速機構(gòu)〔方案Ⅱ〕············································74.3行星輪系減速機構(gòu)〔方案Ⅲ〕··········································75．方案確實定························································85.1原動機的選擇·····················································85.2傳動方案確定·····················································85.3有關(guān)參數(shù)及相關(guān)計算···············································8相關(guān)計算························································8傳動構(gòu)件的尺寸確定·················································86．尺寸與運動綜合····················································96.1執(zhí)行機構(gòu)尺寸設(shè)計··················································96.2驗算曲柄存在條件即最小傳動角······································10曲柄存在條件·····················································106.2.2最小傳動角驗算····················································7.系統(tǒng)總圖···························································118.總體評價···························································118.1課題總結(jié)·························································118.2存在問題·························································12參考文獻(xiàn)·····························································121．臺式電風(fēng)扇搖頭裝置的功能與設(shè)計要求1.1工作原理及工藝過程1.2功能分解電風(fēng)扇的工作原理是將電風(fēng)扇的送風(fēng)區(qū)域進(jìn)行周期性變換，到達(dá)增大送風(fēng)區(qū)域的目的。顯然，為了完成電風(fēng)扇的擺頭動作，需實現(xiàn)以下運動功能要求：〔1〕風(fēng)扇需要按運動規(guī)律做左右擺動，因此需要設(shè)計相應(yīng)的擺動機構(gòu)。

〔2〕風(fēng)扇需要轉(zhuǎn)換傳動軸線和改變轉(zhuǎn)速，因此需要設(shè)計相應(yīng)的齒輪系機構(gòu)。對這兩個機構(gòu)的運動功能作進(jìn)一步分析，可知它們分別應(yīng)該實現(xiàn)以下根本運動：

〔3〕左右擺動有三個根本運動：運動軸線變換、傳動比降低和周期性擺動?！?〕轉(zhuǎn)換運動軸線和改變傳動比有一個根本動作：運動軸線變換。此外，還要滿足傳動性能要求：改變電風(fēng)扇的送風(fēng)區(qū)域時，在急回系數(shù)K＝1.015、擺動角度φ=85°的要求下，盡量保持運動的平穩(wěn)轉(zhuǎn)換和減小機構(gòu)間的摩擦。運動功能圖1.3原始數(shù)據(jù)及設(shè)計要求1.3風(fēng)扇直徑為φ300mm，電扇電動機轉(zhuǎn)速n=1450r/min，電扇搖頭周期T=10s。電扇擺動角度Ψ=85°與急回系數(shù)k=1.015。1.3設(shè)計臺式電風(fēng)扇的搖頭裝置要求能按給定的急回系數(shù)和擺角左右擺動，以實現(xiàn)一個動力下扇葉旋轉(zhuǎn)和搖頭動作的聯(lián)合運動。1.4設(shè)計任務(wù)1．按給定主要參數(shù)，擬定機械傳動系統(tǒng)總體方案。2．畫機構(gòu)運動簡圖。3．分配蝸輪蝸桿、齒輪傳動比，確定他們的根本參數(shù)，設(shè)計計算幾何尺寸。4．解析法確定平面連桿機構(gòu)的運動學(xué)尺寸，它應(yīng)滿足擺角Ψ及形成速比系數(shù)k。并對平面連桿機構(gòu)進(jìn)行運動分析，繪制運動線圖。并驗算曲柄存在條件，驗算最小傳動角〔最大壓力角〕。5．提出調(diào)節(jié)擺角的結(jié)構(gòu)方案，并進(jìn)行分析計算。6．編寫設(shè)計說明書。7．進(jìn)一步完成臺式電風(fēng)扇搖頭機構(gòu)的計算機動態(tài)演示驗證。2．執(zhí)行機構(gòu)的設(shè)計2.1〔方案Ⅰ〕通過構(gòu)件2對構(gòu)件3做相對的圓周轉(zhuǎn)動使構(gòu)件3擺動，從而實現(xiàn)電風(fēng)扇的搖頭動作，如圖1。圖1圖1方案立體圖2.2〔方案Ⅱ〕當(dāng)圓柱凸輪回轉(zhuǎn)時，凹槽側(cè)面迫使構(gòu)件2擺動，從而實現(xiàn)電風(fēng)扇的搖頭功能，如圖2。圖22.3〔方案Ⅲ〕當(dāng)圓盤回轉(zhuǎn)時，凹槽帶動槽輪使導(dǎo)桿擺動，從而實現(xiàn)電風(fēng)扇的搖頭功能，如圖3。圖32.4〔方案Ⅳ〕在曲柄2回轉(zhuǎn)的過程中，桿1實現(xiàn)擺動，從而產(chǎn)生使電風(fēng)扇搖頭的功能，如圖4。圖4由以上四個方案可以看出：方案二、三、四的機構(gòu)都很難難制造且精度要求高，制造本錢也相對要高。傳動機構(gòu)也相比照擬復(fù)雜，且齒輪數(shù)目太多，制造起來麻煩。方案一結(jié)構(gòu)更簡單，本錢相對較低。方案三和方案四相似，結(jié)構(gòu)復(fù)雜制造本錢太高較二還高。因此不難看出，方案一相對較好。所以搖頭機構(gòu)選擇方案一。3．執(zhí)行機構(gòu)的輔助構(gòu)件設(shè)計3.1滑銷控制機構(gòu)〔方案Ⅰ〕通過滑銷和錐齒輪卡和以實現(xiàn)是否搖頭的運動。當(dāng)滑銷下滑實現(xiàn)搖頭，上提那么停止搖頭，如圖5。圖53.2齒輪控制機構(gòu)〔方案Ⅱ〕通過兩個直齒輪的嚙合與否來控制是否搖頭，兩個齒輪嚙合時電風(fēng)扇搖頭、不嚙合時就不搖頭，從而實現(xiàn)了是否搖頭的控制，如圖6。圖64．減速機構(gòu)的設(shè)計4.1蝸桿減速機構(gòu)〔方案Ⅰ〕如圖7圖74.2錐齒輪減速機構(gòu)〔方案Ⅱ〕如圖8圖84.3行星輪系減速機構(gòu)〔方案Ⅲ〕如圖9圖95．方案確實定5.1原動機的選擇籠式三相異步電動機，使用三相交流電、轉(zhuǎn)速與旋轉(zhuǎn)磁場轉(zhuǎn)速不同，可以進(jìn)行幾檔變速。而且籠式電動機的具有簡單、體積小、易維護(hù)、價格低、壽命長連續(xù)運動特性好、轉(zhuǎn)速受負(fù)載轉(zhuǎn)矩波動的影響小和硬機械特性等優(yōu)點。這些特性能夠滿足臺式電風(fēng)扇搖頭裝置的工作特性，所以選擇籠式三相異步電動機作為原動機。5.2傳動方案確定綜合考慮后得出以下傳動方案：在電動機主軸尾部連接蝸輪蝸桿速機構(gòu)以實現(xiàn)減速，蝸輪在與小齒輪連成一體，小齒輪帶動大齒輪，大齒輪與鉸鏈四桿機構(gòu)的連桿做成一體，并以鉸鏈四桿機構(gòu)的連桿為原動件，那么機架、兩個連架桿都做擺動，其中一個連架桿相對機架的擺動即是搖頭動作。扇葉直接接到原動機上，既可以實現(xiàn)電風(fēng)扇的功能。5.3有關(guān)參數(shù)及相關(guān)計算相關(guān)計算電動機轉(zhuǎn)速r=1450r/min搖頭周期T=10s總的傳動比n==，蝸桿頭數(shù)Z1=1，蝸輪的齒數(shù)Z2=62，小齒輪齒數(shù)Z3與大齒輪齒數(shù)Z4確實定由n12===62；n34=；n=n12xn34；那么n34=EQ。那么取Z3=18；Z4=70。傳動構(gòu)件的尺寸確定查閱相關(guān)資料后取：漸開線圓柱齒輪根本參數(shù)取齒輪的齒數(shù)分別為z3=18，z4=70。模數(shù)m=1.25，ha*=1，c*=0.25〔ha*為齒頂高系數(shù)，c*為頂隙系數(shù)〕，壓力角α=200。分度圓直徑d3=mz3=1.25x18=22.5〔mm〕；d4=mz4=1.25x70=87.5〔mm〕。齒頂高h(yuǎn)a=ha*m=m=1.25mm。齒根高h(yuǎn)f=〔ha*+c*〕m=〔1+0.25〕x1.25=2.8125〔mm〕。齒全高h(yuǎn)=ha+hf=1.25+2.8125=4.0625〔mm〕。齒頂圓直徑da3=d3+2hda4=d4+2h齒根圓直徑df3=d3-2hf=22.5-2x2.8125=16.875〔mm〕；df4=d4-2hf=87.5-2x2.8125=81.875〔mm〕?；鶊A直徑db3=d3cosα=22.5xcos200=21.14〔mm〕；db4=d4cosα=87.5xcos200=82.22〔mm〕。齒距p=πm=3.14x1.25=3.93〔mm〕。齒厚s=πm/2=1.96〔mm〕。齒槽寬e=πm/2=1.96〔mm〕。中心距a=〔d3+d4〕/2=55mm。頂隙c=c*m=0.25x1.25=0.3125〔mm〕。普通圓柱蝸桿傳動幾何尺寸計算查表取得：中心距a取40mm，i=62，m=1，d1=18，z1=1，z2=62，x2=0.0000，γ=3010/47//，ha*=1，c*=0.25。齒形角α=200〔ZA型〕。蝸輪變?yōu)橄禂?shù)x2=0.0000。蝸桿軸向齒距px=πm=3.14mm。蝸桿齒頂高h(yuǎn)a1=ha*m=1mm。頂隙c=c*m=0.25mm。蝸桿齒根高h(yuǎn)f1=〔ha*+c*〕m=1.25mm。蝸桿齒高h(yuǎn)1=ha1+hf1=2.25mm。蝸桿齒寬b1取19.5mm。蝸輪分度圓直徑d2=mz2=62mm。蝸輪齒根圓直徑df2=d2-2hf2=59.5mm。蝸輪齒頂高h(yuǎn)a2=m〔ha*+x2〕=1mm。蝸輪齒根高h(yuǎn)f2=m〔ha*-x2+c*〕=1.25mm。蝸輪齒高h(yuǎn)2=ha2+hf2=2.25mm。蝸輪齒頂圓弧半徑Ra2=d1/2-m=8mm。蝸桿軸向齒厚sx1=px/2=1.57mm。蝸桿法向齒厚sn1=sx1cosγ=1.568mm。蝸桿節(jié)圓直徑d1/=d1+2x2m=18mm蝸輪節(jié)圓直徑d2/=d2=62mm。6．尺寸與運動綜合6.1執(zhí)行機構(gòu)尺寸設(shè)計設(shè)計與計算〔1〕由急回系數(shù)K計算極位夾角。由式=180，其中K=1.015；得=1.340〔2〕選定比例尺μ按條件畫出搖桿BC的兩個極限位置C1D和C2D，連C1,C2兩點，以C1為直角頂做∠C2C1M=85o,再做∠C1C2N=85o,C1M與C2N交于P點，以PC2為直徑做ΔC1C2P的外接圓。在此圓上任取一點A作為曲柄的固定鉸鏈中心，連接AC1和AC2因同一圓弧的圓周角相等，故∠C1AC2=∠C1PC2=，令A(yù)B=a,BC=b,CD=c,DA=d.那么AC1=b-a,AC2=b+a。圖一〔總體示意圖〕圖二〔局部圖〕〔3〕上圖四桿機構(gòu)假設(shè)取AD為機架那么為曲柄搖桿機構(gòu)，而電風(fēng)扇的搖頭四桿機構(gòu)是要是雙搖桿機構(gòu)，所以取以CD為機架的倒置四桿機構(gòu)?！?〕計算各桿的實際長度。分別量取圖中AB、B2C2、C1D、AD的長度，計算得a=μAB1=0.6μ，b=μB2C2=1.94μ，c=μC2D=μ，d=μAD=2.02μ?！睠2D=1mm〕因為本設(shè)計使用曲柄連桿機構(gòu)的倒置機構(gòu)〔即雙搖桿機構(gòu)〕，所以取桿CD為機架。那么取d=88mm，即μ=88。所以：a=74.77mm，b=81.62mm，c=88mm6.2驗算曲柄存在條件即最小傳動角曲柄存在條件〔1〕由上圖可知A為整轉(zhuǎn)副，那么以A為圓心a為半徑的圓上各點都能與B構(gòu)成整轉(zhuǎn)副，即a+d≤b+c①,│d-a│≥│b-c│②假設(shè)a≤d,由式②可得：a+b≤c+d或a+c≤b+d，又由式①可得：a≤b,a≤c,a≤d；假設(shè)d≤a,由式②可得：d+b≤a+c,d+c≤a+d，又由式①可得d≤a,d≤b,d≤c?！?〕由以上各式可得曲柄存在條件：組成該轉(zhuǎn)動副的兩個構(gòu)件中必有一個構(gòu)件為最短構(gòu)件，且四桿機構(gòu)的長度滿足桿長之和條件。6.2.2cosδmin=[b2+c2-(d-a)2]/2bc=0.906那么δmin=82.46o；cosδmax=[b2+c2-(d+a)2]/2bc=-1.428那么δmax=126.34o；那么傳動角EQ的范圍為〔53.66o，82.46o〕，符合EQmin≥40o的條件。7.系統(tǒng)總圖臺式電風(fēng)扇搖頭系統(tǒng)結(jié)構(gòu)簡圖8.總體評價8.1課題總結(jié)通過這次課程設(shè)計，讓我對機械原理這門課程有了更深入的了解，對以前不熟悉的環(huán)節(jié)理解。雖然在設(shè)計的過程中遇到了好多麻煩，但是經(jīng)過自己認(rèn)真的思考和查閱資料，以及和同學(xué)一起討論最終把問題都解決了。這次設(shè)計給我一個感受，學(xué)習(xí)的過程中要懂得把所學(xué)的東西聯(lián)系起來并運用到實踐中來，而不是把每個章節(jié)分開來理解。通過這個實踐我學(xué)得了好多，同時認(rèn)識到理論聯(lián)系實際的重要性，不僅加深了我對課程的理解程度而且也激起了我學(xué)習(xí)的興趣。機械原理課程設(shè)計是使我們較全面系統(tǒng)的掌握和深化機械原理課程的根本原理和方法的重要環(huán)節(jié)，是培養(yǎng)我們機械運動方案設(shè)計創(chuàng)新設(shè)計和應(yīng)用計算機對工程實際中各種機構(gòu)進(jìn)行分析和設(shè)計能力的一門課程。經(jīng)過這幾天的設(shè)計，讓我初步了解了機械設(shè)計的全過程，可以初步的進(jìn)行機構(gòu)選型組合和確定運動方案；使我將機械原理課程各章的理論和方法融會貫穿起來，進(jìn)一步穩(wěn)固和加深了所學(xué)的理論知識；并對動力分析與設(shè)計有了一個較完整的概念；提高了運算繪圖遺跡運