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Gear DesignHomework StepTasks ComputationResults l.Selection1Select spur gears Spurgears
1.of gear2Since conveyoris anordinary machinerywhose Grade7type,quality speedis notvery high,select quality Grade gradeand7GB10095-88materials3Material selectionSelect40Cr with hardness280HBS for the40Cr forpinion pinionCarburizingand quenching,and45carbon45carbon steelfor steelwithhardness240HBS forthe Gearsgeartempering Zi=214select the number ofteeth ZiZ2=67Select Zi=21,the numberof gearteeth isZ2=UZJ\=
3.2X22=
67.2SO selectZ2=67From thedesign formulaEq.6-13lDesign valuesto beused inthe formulalselect atrial factorKt=
1.5Kt=
1.52The torquethe piniontransmitted isT\=
9.948x
104.
95.5X105P.n\N・mm=
95.5xl05xl0/960A^-mm=
9.948xl04^-//tm pd=\3Select facewit factorpi fromTable6-6pd=\4The elasticcoeffcient ofthe selectedmaterial isZE=
189.9MPa2found tobe ZE=
189.9MPd^5Contact endurancelimit ofthe opinioncan befound OH lim2=630A/Pf/as GMiim1=630MPa accordingto itssurface O1I lim2=5SQMPa hardness;Similarly.contact endurancelimit ofthe gear is8iim2=5S0MPa6thenumberof loadcycles is calculated byEq6-50M=
4.147x19as M=
1.296x19N\=60ni jLh=60x960x1x2x8x300x15=
4.147x19M=
4.147x19/
3.2=
1.296x1O7Life factorforthecontact strengthis obtainedKHN\=
0.90KHN\=
0.90KHNZ=
0.95from Figure6-22as KHN=
0.958Calculate allowablecontact stressFrom[cnf]=561MPa Eq.6-51,select safetyfactor SH=1\cm]2=551MPa allowablecontact stressiscalculatedas「1KHN\01Hlim1八八[h/]=-------------=
0.9x630MPa=567MPa Sr1KHN2JH lim2uco/n uuiJi/n[⑪上=---------------=0・95x580A/P〃=55\MPa2Design calculationdu=
65.3961d\t
2.32J也^也手mm Vpel U\[JH L…L5X
9.948X
143.2+
11189.
8、=
2.323-----------------------------------------V
1.
13.2I551-
65.396mm v=
3.29m/s2Calculate circumferentialvelocity u7id\tn\v=----------------7x
65.396x960m!s=
3.29rr」l s60x100060x10003Calculate face width b=
65.396〃*%b=pd,dv=\x
65.396=
65.396mm4calculate theratio offacewidthand toothheight加=
3.114mm b/h Moduleh=
7.007mm mt=d\!z\=
65.396/21=
3.1\^mni b/h=
9.33Tooth heighth=
2.25mt=
2.25x
2.971=
6.68mm b/h=
71.889/
6.68=
10.765calculate theload factorK=l.15Check dynamicload factorKida=Kj7a—1K=L14=
1.423According tov=
3.228m/s,qualityGrade
7.K”
1.40KHCI—KFU—1K=
1.622For aspurgear,KA=1From Table10-2,we haveDetermine theload distributionfactor intooth及direction fromTable10-4Kw=L423K/=l.40K=KAKVKHCXH=1X
1.14X1X
1.423=
1.6226The modifiedreference diameterfrom actualload Ji=
67.123mm factorK canbe obtainedfrom Eq.6-14di=di^K/Ki=
65.396xV
1.622/
1.5=
67.123mm7Compute modulem m=
3.T96mm m=d\/z\=
67.123/21=
3.196mm
3.check bythe bending6=
99.04MPa strengthCalculate thebending strengthYFa=
2.76o KFtYFaYsaJF—CFoYSa=----------------Ysa=\.56bm_L622x2264义13义
2.76x L56Ft=
2.964X7V~
65.396x
3.196JFE\-500Af尸=
99.04MP7FE2=3S0MPa Accordingto Table10-5YFa=
2.76Ra=l.56人空二2X
9.948X*.964KN d\
70.641Calculate theendurance bendingstrength Accordingto10-20C JFE\=500A/P Wehave勺TFE2=3S0MPa Accordingto10-18KFN2=
0.85KFNZ-
0.88「i KFN\JFE\
0.85X5001Z-TYT1——425MPa[S_1,4|-i KFNICFEZ
0.88x
380238.86MP叵卜s~
1.4=
99.04[o]=
238.86The spurgearissafe。