#(2)按齒面接觸強(qiáng)度設(shè)計(jì)試選載荷系數(shù)K=1.3t計(jì)算小齒輪傳遞的扭矩T=95.5X105P/n=95.5X105111X8.762/970=86265X105Nmm由表10-7選取齒輪寬系數(shù)0=1d由表10-6查得材料彈性系數(shù)Z=189.8MPa2E由圖10-21d按齒面硬度查得小齒輪的接觸疲勞強(qiáng)度極限。=600Mpa大齒輪的接觸疲勞強(qiáng)度疲勞極限。Hlim1=550MpaHlim2計(jì)算應(yīng)力循環(huán)次數(shù)N=60njL=60X970X(2X8X300X8)X1=2.235X1091hN=2.235X109/2.829=7.9X1082由圖10-19取接觸疲勞壽命K=0.9;K=0.92HN1HN2計(jì)算接觸疲勞許用應(yīng)力(取失效概率為1%,安全系數(shù)S=1)[o]=KXo/S=0.9X600/1=540MpaH1HN1Hlim1[o]=KXo/S=0.92X550/1=506MpaH2HN2Hlim2計(jì)算:小齒輪分度圓直徑d,代入［o］中較小的值dit=64.365mmdit=64.365mm11

g.計(jì)算模數(shù)mm二d1=69.278=2.89mmZ124(3)按齒根彎曲強(qiáng)度設(shè)計(jì)1)確定各公示內(nèi)的計(jì)算數(shù)值由圖10-20C查得小齒輪的彎曲疲勞極限c=500MpaFE1大齒輪的彎曲極限c=380MpaFE2由圖10-18取彎曲疲勞壽命系數(shù)k=0.88k=0.9FN1FN2C.計(jì)算彎曲疲勞許用應(yīng)力取彎曲疲勞安全系數(shù)s=1.4,則c]=KFN1CFE1=0.88x500=314.286f1S1.4c]=KFN2cFE2=0.9x380=244.286F2S1.4計(jì)算負(fù)載系數(shù)KK=KKKK=1X1.14X1X1.4=1.596AVFaFB查取齒形系數(shù)由表10-5查得Y=2.65Y=2.248Fa1Fa2查取應(yīng)力校正系數(shù)由表10-5查得Y=1.58Y=1.746Sa1Sa2計(jì)算大小齒輪的并加以比較F]丿牛1=2.65x1.58=0.01332c」314.286F1K=1.596

YY―g2ff^2F22.248xYY―g2ff^2F22.248x1.746=0.01607244.286由此可見，大齒輪數(shù)值大2）設(shè)計(jì)計(jì)算\2KTYY—]2x1.596x8.6265“門小心=[97m>3i=3x105x0.01607=1.9/3QdZj叩1x242圓整后得m=2按接觸強(qiáng)度算得分度圓直徑d=74.7211所以，Z=佇=竺8.35m2Z=2.829X35沁99.05取Z=1002(4)幾何尺寸計(jì)算a.計(jì)算分度圓直徑M=2mmd=Zm=35X2=70mm11d=Zm=100X2=200mm22計(jì)算中心距d+d70+200a=T2==135mm22計(jì)算齒輪寬度b=?dd=1X70=70mm取B=70mm,B=75mm1213.低速級(jí)齒輪傳動(dòng)設(shè)計(jì)(原理同高速級(jí)齒輪傳動(dòng)設(shè)計(jì)方案,求得以下數(shù)據(jù))材料:小齒輪40C280HBS大齒輪45鋼(調(diào)質(zhì))r240HBS選z'=24z'=24X2.176=52.224取z'=53K=1.3122t?d二1Z=189.8MPa2T二95.5x105p3=490086N.mm3n3查得a'=600Mpaq'=550MpaHlim1Hlim2N'=60njL=60X15745X1X(2X8X300X8)=3.62813nX108’N'3.628xl08—"N一一—一一1.667x1082u2.176由圖取k'=0.92K'=0.95HN1HN2rrrrQ]-Khn1^恤1-552MPaQ]-Khn2-552.5MPaH1SH2Sd=115.285mmv'-0.95m/sb'-115.285mm3tO，b'm一4.804h'-10.808—一10.667th'Kv'=1.05K'-K'-1K'-1K'-1.435HaFaAHPK'-1.35FP所以,K'-1.507d=121.105mmm=5.046mm3查得Q'-500MPaQ'-380MPaK'-0.88FE1FE2FN1K'-0.9FN1所以,Q]'-314.286MPaQ]'-244.286MPaF1F2d-70mm1d-200mm2A=135mmb-70mmB-75mm1B-70mm2K'-1.4175

12.K'=K'K'K'K'=1.4175AvFaFP13?查得Y'=2.65Y'=2.248Fa1Fa2Y'=1.58Y'=1.746SalSa2rrrrYYYY匸ja1=0.01332g『2=0.01607F1F2所以,大齒輪的數(shù)值大m>2.720圓整m=3fZ'=2沁31Z'=24x2.176沁531m2d=Zm=31x3=93mmd=Zm'=68x3=204mm1122ffrd+d予"門匕Fi'a=亠=148.5mmb—odd—93mm21所以,B=95mmB=100mm21六、軸的設(shè)計(jì)計(jì)算1)輸入軸的設(shè)計(jì)初算軸徑選用45鋼(調(diào)質(zhì))硬度217~255HBS,查課本P235(10-2）得C=115d>c3￡—115J&7"'—23.95mm3n3970i1考慮有一鍵槽,直徑增大5%d=23.95（1+5%）=25.15mm所以,初選d=27mm軸結(jié)構(gòu)設(shè)計(jì)m'—3mmZ'Z'=311Z'=682

fd=93mm1d=204mm2a=148.5mmb=93mmB=100mm1B=95mm2齒輪相對(duì)軸承非對(duì)稱分布,右面由軸肩固定,左面由套筒固定,連接以平鍵作過渡配合固定兩軸承分別以軸肩和筒定位,則采用過渡配合固定確定各段直徑和長度I段:d=27mm長度取L=50mm11因?yàn)?h=2cc=1.5mmII段:d=d+2h=27+2X3=33mm21L=20(套筒)+55(聯(lián)軸箱與外壁距)=75mm2III段:d=38mm3初選用7208c型角接觸球軸承,內(nèi)徑為40mm,寬度為18mm,D=80mm,L=18mm3所以，取d=40mmL=18mm33IV段:d=d+2h=38+6=44mm43L=217.5mm4V段:取d=40mmL=18mm55則軸承跨距L=235.5mm3.按彎矩復(fù)合強(qiáng)度設(shè)計(jì)計(jì)算①已知d=70mm1T=86265N.mm1F=246.4714NtF=897.083Nr②圓周力:2TF二i

tdi2x8626570=2464.714N③徑向力:F二Ftana=2464.714Xtan20°=897.083Nrt④由上可知:L=64mmAL=214mmL=134mmBCL=64mmAL=214mmBL=134mmC1）繪制軸受力簡圖(a）2)繪制垂直彎矩圖(b)F=206.695NBy軸承受反力F=206.695NByAy

F=1897.289NF=567.416NAzBz截面C在垂直面彎矩Mcl—fL=690.388X64=44.18n?mAyA3)繪制水平面彎矩圖(c)截面C在水平面彎矩為Mc2—fL=1897.289X64=121.43n?mAyA4)繪制合彎矩圖(d)Mc=jMcj+Mej=J121.432+44.182=129.22n?m5)繪制扭矩圖(e)T=9.55X(PII/nII)X106=T1=86.265N?m6）繪制當(dāng)量彎矩(f）取a=1則M=[M2+(aT)2]2—[129.222+244.032]2=276.13N?mee07)校核危險(xiǎn)截面=JM2+(aT）2J29.222+86.2652gia一__0——18.24<[g]eW0.1X443r該軸強(qiáng)度足夠(2)輸出軸的設(shè)計(jì)計(jì)算a.按扭矩初算軸徑先用45鋼(調(diào)質(zhì))硬度217s255HBS,由P235表10-2取C=115M—129.22N-mCT—86.265N-m

d>C3P/n二115#8.08/157.572二42.72mm*iiiiii考慮到有鍵槽增大5%d=42.72x(1+5%)=44.86mmb.聯(lián)軸器型號(hào)的選取查表14-1,取Ka二1.5T二KT二1.5x490.086二735.129N-mcaa3按計(jì)算轉(zhuǎn)矩T小于聯(lián)軸器的公稱轉(zhuǎn)矩的條件,查ca表8-2選用YL11型凸緣聯(lián)軸器其公稱轉(zhuǎn)矩為1000N-m,半聯(lián)軸器孔徑為50mm,故選d=50mm1C.軸的結(jié)構(gòu)設(shè)計(jì)1.軸的零件定位,固定和裝配齒輪相對(duì)軸承非對(duì)稱布置,左面用套筒定位,右端用軸肩定位,周向定位米用鍵和過度配合,兩軸承分別從軸肩和套筒定位,周向永過度或過盈配合,軸呈階狀,左軸承從左面,齒輪套筒右軸承和皮帶輪從右裝入,低速級(jí)小齒輪與輸出軸設(shè)計(jì)成齒輪軸2.確定軸的各段直徑和長度T=735.129N-mcaI段:d'=50mm長度取L=84mm11II段:d'=d'+2h=50+2x2x1.5=56mm21L=20+55=75mm2III段:d'=d'+2h=62mm32初選用7213c型角接觸球軸承,內(nèi)徑為65mm,寬度23mm,D=120mmL=23mm3所以,d3=65mmL=23mm3閃段:d=68mm'L=90mm4'V段:d=72mm'L=10mm5'刑段.d=68mm'L=95mm6W段:d7=65mm'L=43mm73?按彎扭復(fù)合強(qiáng)度計(jì)算d=50mm1fL=84mm1td=56mm2fL=75mm2fd=65mm3fL=23mm3fd=68mmfL=90mmfd=72mm5fL=10mm5fd=68mmfL=95mm6fd=65mm7fL=43mm7F=5041.50NtF=1835.00Nr①已知d=93mmi=T=234431N-mm2②圓周力廠2T2x234431F=—==5041.5Ntd'931③徑向力F=Ftan20。=1835.00r④由圓可知L=159mmL=79mmABL=11.5mmC⑴求支反力F=608.76NAy

F=1225.24NByF=1673.44NAz

F=3368.06NBz⑵截面C在垂直面彎矩M'=283.135N⑵截面C在垂直面彎矩M'=283.135N-mCT'=234.431N-m⑷扭矩2+fM八IC2丿2二283.135N-m11.68MPa<[a]e-1M=FxL=96.739N-mCAyA截面C在垂直水平面彎矩M=FxL=266.076N-mC2AzA——T二234.431N-m2口9550xPT二2n2(5)校核危險(xiǎn)截面強(qiáng)度6'八叫二n.69MPa<la]-i■Cw故,該軸強(qiáng)度足夠該軸彎矩圖及扭矩圖如下圖

I段:由軸承可知d=40mmL=38mm11II段d=40+2x21.5=46mmL=70mm=B222III段d=50mmL=125mm33ffW段(齒輪軸)d"=40mmL4=18mm4貝峙由承跨距L=64+92.5+76.5=233mmc.軸上零件的定位。固定和裝配:齒輪相對(duì)軸承非對(duì)稱分布,左面有套筒定位。右面有套筒定位,高速小齒輪于軸III設(shè)計(jì)成齒輪軸。軸承由軸肩及套筒固定。按彎矩復(fù)合強(qiáng)度設(shè)計(jì)計(jì)算d=40mmiL=38mm1d=46mm2L=70mm2d=50mm3L=125mm3ffd=40mm4ffL=18mm4

oDfa)￡MonoDfa)￡MonTe軸2七、滾動(dòng)軸承的選擇及校核計(jì)算I軸:7208cII軸:7208c預(yù)計(jì)壽命:8III軸:7213c預(yù)計(jì)壽命:8X2X365X8=46720小時(shí)X2X365X8=46720h計(jì)算輸入軸承I8=46720ha.軸承所受徑向力Fr=897.083N軸向力Fa=0Fa/Fr=0由表12-6,得,X=1Y=0X=1Y=0P=986.791Nb.計(jì)算當(dāng)量動(dòng)載荷P=fp(xFr+YFa)fp取1.1貝UP=986.791NP=1.1x(1x897.083+0)=986.791N

C.驗(yàn)算壽命T106Cr10636800、7CCCLFCCL-()s-x()3h—890571.95h>46720hh60np60x970986.791???所選軸承7208c滿足要求(2)計(jì)算輸出軸承(III)軸承所受徑向力:Fr=2912.3NFa=0Fa/Fr=0X=1Y=0計(jì)算當(dāng)量動(dòng)載荷:P=fp(xFr+YFa)P=1.1X(1X2912.3+0)+3203.53N驗(yàn)算壽命T106Cr106z69.8x103L(——)sx()3-1094929h>46720hh60np60x157.453203.533???所選偶成7213c滿足要求八、鍵連接的選擇及校核計(jì)算1..聯(lián)軸器與輸入軸系采用平鍵連接車由徑d-27mmL—50mm查手冊p51,選用c型鍵得鍵c8X73b3l-L——-45—_x8-33122鍵長L=37mm￡-86.2565N-mn-7mmc-4T/(dhl)-48.05Mpa<[c]-110MPap1p2.輸出軸與齒輪連接用平鍵軸徑d-68mmL—95mmL-890571.95hHX'-1Y'-0P'-3203.53NL-1094929hhC鍵8X7c-48.05MPapA鍵20X12

查手冊P51選用A型平鍵鍵A20X12鍵長90mmT二490-086N-mh=12mmQ二4T/dhl=4x490.086/(68x12x75)=32.03MPa<110MPap3.中間軸與齒輪用平鍵連接軸徑d=46mmL=70mm查手冊p51選A型平鍵鍵A14X9l=L-b鍵長63T2=234?43Nh=9mmc=46.23Mpa<Q]=110Mpapp4.輸出軸與聯(lián)軸器用平鍵聯(lián)接軸徑d=50mmL'=84mm查手冊p51選A型平鍵鍵A14X9l=L-b=80-14=66mmT3=490.086NMh=9mmc=62.23Mpa<[c]=110Mpappc=32.03MPapA鍵14X9c=46.23MPapA鍵14X9c=62.23MPap

個(gè)人小結(jié)開學(xué)至今,我們經(jīng)歷了為期長達(dá)十天之久的實(shí)訓(xùn)課,即機(jī)械設(shè)計(jì)課程設(shè)計(jì)。我們所得到的任務(wù)是憑借極少的數(shù)據(jù),自行設(shè)計(jì)個(gè)減速箱。對(duì)于素來動(dòng)手極少的我而言,這可謂是一個(gè)非常反復(fù)的工作。首先,在和小組成員互動(dòng)中發(fā)現(xiàn),此設(shè)計(jì)需要高度的團(tuán)隊(duì)合作,因?yàn)橐蝗酥斐傻挠?jì)算錯(cuò)誤幾乎可以說是致命的。諸女如在對(duì)齒輪進(jìn)仃的計(jì)算和校驗(yàn),由于各種原因?qū)е虑扒昂蠛笥?jì)算了多次,大大影響了整體速度,而重復(fù)計(jì)算某一樣?xùn)|西所帶來的煩躁感也在整個(gè)團(tuán)隊(duì)中揮之不去。另外通過實(shí)訓(xùn)讓我們進(jìn)步掌握了機(jī)械原理以及機(jī)械設(shè)計(jì)課堂