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机械类外文文献翻译
文件翻译
英文原文:
NOVELMETHODOFREALIZINGTHEOPTIMALTRANSMISSIONOFTHECRANK-AND-ROCKERMECHANISMDESIGN
Abstract:
Anovelmethodofrealizingtheoptimaltransmissionofthe
crank-and-rockermechanismispresented.Theoptimalcombinationdesignismadebyfindingtherelatedoptimaltransmissionparameters.Thediagramoftheoptimaltransmissionisdrawn.Inthediagram,therelationamongminimumtransmissionangle,thecoefficientoftravelspeedvariation,theoscillatingangleoftherockerandthelengthofthebarsisshown,concisely,convenientlyanddirectly.Themethodpossessesthemaincharacteristic.Thatitistoachievetheoptimaltransmissionparametersunderthetransmissionanglebydirectlychoosinginthediagram,accordingtothegivenrequirements.Thecharacteristicsofthemechanicaltransmissioncanbeimprovedtogaintheoptimaltransmissioneffectbythemethod.Especially,themethodissimpleandconvenientinpracticaluse.
Keywords:
Crank-and-rockermechanism,Optimaltransmissionangle,Coefficient
oftravelspeedvariation
INTRODUCTION
Byconventionalmethodofthecrank-and-rockerdesign,itisverydifficulttorealizetheoptimalcombinationbetweenthevariousparametersforoptimaltransmission.Thefigure-tabledesignmethodintroducedinthispapercanhelpachievethisgoal.Withgivenconditions,wecan,byonlyconsultingthedesigningfiguresandtables,gettherelationsbetweeneveryparameterandanotherofthedesignedcrank-and-rockermechanism.Thustheoptimaltransmissioncanberealized.
Theconcerneddesigningtheoryandmethod,aswellastherealcasesofitsapplicationwillbeintroducedlaterrespectively.
1ESTABLISHMENTOFDIAGRAMFOROPTIMALTRANSMISSIONDESIGN
Itisalwaysoneofthemostimportantindexesthatdesignerspursuetoimprovetheefficiencyandpropertyofthetransmission.Thecrank-and-rockermechanismiswidelyusedinthemechanicaltransmission.Howtoimproveworkabilityandreduceunnecessarypowerlossesisdirectlyrelatedtothecoefficientoftravelspeedvariation,theoscillatingangleoftherockerandtheratioofthecrankandrocker.Thereasonablecombinationoftheseparameterstakesanimportanteffectontheefficiencyandpropertyofthemechanism,whichmainlyindicatesintheevaluationoftheminimumtransmissionangle.
Theaimrealizingtheoptimaltransmissionofthemechanismishowtofindthe
maximumoftheminimumtransmissionangle.Thedesignparametersarereasonablycombinedbythemethodoflesseningconstraintsgraduallyandoptimizingseparately.Consequently,thecompleteconstraintfieldrealizingtheoptimaltransmissionisestablished.
Thefollowingstepsaretakenintheusualdesignmethod.Firstly,theinitial
valuesofthelengthofrockerl3andtheoscillatingangleofrockeraregiven.
ThenthevalueofthecoefficientoftravelspeedvariationKischoseninthe
permittedrange.Meanwhile,thecoordinateofthefixedhingeofcrankApossibly
realizediscalculatedcorrespondingtovalueK.
Lengthofbarsofcrankandrockermechanism
AsshowninFig.1,leftarcC2GisthepermittedfieldofpointA.ThecoordinatesofpointAarechosenbysmallstepfrompointC2topointG.
ThecoordinatesofpointAare
y
A
y
h
0
(1)
c2
xA
R2
yA2
(2)
whereh0,thestep,isincreasedbysmallincrementwithinrange(0,H).Ifthe
smallerthechosenstepis,thehigherthecomputationalprecisionwillbe.Risthe
radiusofthedesigncircle.disthedistancefromC2toG.
dl3cos
2Rcos(
)l3
cos
(3)
2
2
2
CalculatingthelengthofarcAC1
and
AC2,thelengthofthebarsofthe
mechanismcorrespondingtopointA
isobtained[1,2].
1.2Minimumtransmissionangle
min
Minimumtransmissionangle
[3]
min(seeFig.2)isdeterminedbytheequations
cos
cos
l22
l32
(l4
l1)2
min
2l2l3
(4)
l22
l32
(l4
l1)
2
max
2l2l3
(5)
min180max(6)
wherel1——Lengthofcrank(mm)
l2——Lengthofconnectingbar(mm)
l3——Lengthofrocker(mm)
l4——Lengthofmachineframe(mm)
Firstly,wechooseminimumcomparingminwithmin.Andthenwerecord
allvaluesofmingreaterthanorequalto40andchoosethemaximumofthem.
Secondly,wefindthemaximumofmincorrespondingtoanyoscillatingangle
whichischosenbysmallstepinthepermittedrange(maximumofminis
differentoscillatingangleandthecoefficientoftravelspeedvariationK).
Finally,wechangethelengthofrockerl3bysmallstepsimilarly.Thuswe
mayobtainthemaximumof
min
correspondingtothedifferentlengthofbars,
differentoscillatingangle
andthecoefficientoftravelspeedvariationK.
Fig.3isaccomplishedfromTableforthepurposeofdiagramdesign.
Itisworthpointingoutthatwhateverthelengthofrockerl3isevaluated,the
locationthatthemaximumofminarisesisonlyrelatedtotheratioofthelengthof
rockerandthelengthofmachineframel3/l4,whileindependentofl3.
2DESIGNMETHOD
Realizingtheoptimaltransmissiondesigngiventhecoefficientoftravelspeedvariationandthemaximumoscillatingangleoftherocker
Thedesignprocedureisasfollows.
(1)
AccordingtogivenK
and
takenaccounttotheformulatheextreme
includedangle
isfound.Thecorrespondingratioofthelengthofbarsl3/l4is
obtainedconsultingFig.3.
K
1
(7)
K
180
1
(2)
Choosethelengthofrockerl3
accordingtotheworkrequirement,thelength
ofthemachineframeisobtainedfromtheratiol3/l4.
(3)
ChoosethecentreoffixedhingeD
asthevertexarbitrarily,andplotan
isoscelestriangle,thesideofwhichisequaltothelengthofrockerl3(seeFig.4),and
C1DC2
.Thenplot
C2M
C1C2,draw
C1N
andmakeangle
C2C1N
90
.Thusthepointofintersectionof
C2M
and
C1N
isgained.
Finally,drawthecircumcircleoftrianglePC1C2.
(4)Plotanarcwithpoint
D
asthecentreofthecircle,l4
astheradius.Thearc
intersectionsarc
C2G
atpoint
A.Point
A
isjustthecentreofthefixedhingeof
thecrank.
Therefore,fromthelengthofthecrank
l1(AC1AC2)/2
(8)
andthelengthoftheconnectingbar
l2AC1l1
(9)
wewillobtainthecrankandrockermechanismconsistedofl1,l2,l3,andl4.Thus
theoptimaltransmissionpropertyisrealizedundergivenconditions.
2.2Realizingtheoptimaltransmissiondesigngiventhelengthoftherocker(orthelengthofthemachineframe)andthecoefficientoftravelspeedvariation
Wetakethefollowingsteps.
(1)
Theappropriateratioofthebarsl3/l4canbechosenaccordingtogivenK.
Furthermore,wefindthelengthofmachineframel4(thelengthofrockerl3).
(2)
Thecorrespondingoscillatingangleoftherockercanbeobtainedconsulting
Fig.3.Andwecalculatetheextremeincludedangle.
3DESIGNEXAMPLE
Theknownconditionsarethatthecoefficientoftravelspeedvariation
K1.1818andmaximumoscillatingangle40.Thecrankandrocker
mechanismrealizingtheoptimaltransmissionisdesignedbythediagramsolution
methodpresentedabove.
First,withEq.(7),wecancalculatetheextremeincludedangle
15.Then,
wefindl3/l4
0.93consultingFig.3accordingtothevaluesof
and.
Ifevaluate
l350
mm,thenwewillobtain
l4
50/0.9353.76mm.
Next,drawsketch(omitted).
Asresult,thelengthofbarsisl1
16
mm,l2
46mm,l3
50
mm,l4
mm.
Theminimumtransmissionangleis
l
22
l32
(l4
l12)
minarccos
2l2l3
Theresultsobtainedbycomputerarel1
mm,l2
mm,
l3
50.0000mm,l4
53.8986mm.
ProvidedthatthefiguredesigniscarriedundertheconditionoftheAutoCAD
circumstances,veryprecisedesignresultscanbeachieved.
4
CONCLUSIONS
Anovelapproachofdiagramsolutioncanrealizetheoptimaltransmissionofthecrank-and-rockermechanism.Themethodissimpleandconvenientinthepracticaluse.Inconventionaldesignofmechanism,taking0.1mmasthevalueofeffectivetheprecisionofthecomponentsizeswillbeenough.
译文:
认识曲柄摇臂机构设计的最优传动方法
纲要:
一种曲柄摇臂机构设计的最优传动的方法被提出。
这类优化组合设计被用
来找出最优的传达参数。
得出最优传达图。
在图中,在极小的传动角度之间,滑
移速度变化系数,摇臂的摇动角度和杆的长度被直观地显示。
这是这类方法拥有的主要特点。
依据指定的要求,它将传动角度之下的最优传动参数直接地表达在图上。
经过这类方法,机械传动的特征能用以获取最优传动成效。
特别是,这类方法是简单和适用的。
重点字:
曲柄摇臂机构最优传动角度滑移速度变化系数
1介绍
由曲柄摇臂机构设计的惯例方法,在各种各种的参量之间很难找出优化组合的最优传动。
经过本文介绍的图面设计方法能够帮助达到这个目的。
在指定的状况下,经过观查设计图面,我们就能获取每个参量和此外一个曲柄摇臂机构设计之间的联系。
由因认识最优传动。
详细的设计的理论和方法,以及它们各自的应用案例将在以下介绍。
1优化传动设计的成立
优化传动的设计向来是设计师改良传输效率和追求产量的最重要的索引的
中间一个。
曲柄摇臂机构被宽泛应用在机械传动中。
怎样改良工作效率和减少剩余的功率损失直接地与滑移速度变化系数,摇臂的摇动角度和曲柄摇臂的比率相关系。
这些参数的合理组合采纳对机械效率和产量有重要作用,这些主要表此刻极小的传输角度上。
认识机械优化传动目的是找到极小的传输角度的最大值。
设计参数是适量地减少限制并且分开的合理优化方法的联合。
所以,完整限制领域的优化传动成立了。
以下步骤被采纳在往常的设计方法。
第一,丈量出摇臂的长度l3和摇臂的
摇动角度
的初始值。
而后滑移速度变化系数
K的值被定在同意的范围内。
同
时,曲柄固定的铰接座标
A可能被以为是随意值
K。
曲柄摇臂机构杆的长度
由图,左弧C2G是点A被同意的领域。
点A的座标的选择从点C2到点
G。
点A的座标是
yA
yc2
h0
(1)
xA
R2
yA2
(2)
当h0,高度,在range(0,H)被渐渐增添。
假如选的越小,计算精度将越高。
R
是设计圆的半径。
d是从C2到G的距离。
dl3
cos2Rcos(
)l
3
cos
(3)
2
2
2
计算弧AC1和AC2的长度,机械杆对应于点
A的长度是obtained[1,2]。
1.2极小的传动角度
极小的传动角度
min
min
(拜见Fig.2)由equations[3]确立
cos
l22
l32