Cycloidalprofilesareudforthemostpartintheelementsoflsulk
impellermachines,whileinvoluteprofilesareudingearmachinery.
Somefirmshaverecentlycometoucycloidalprofilesingearpumps.
Thus,the"E.Z.}rire"Companymanufacturesgearpumps[1]with
helicalherringbonegears,theprofileofwhichlookslikethe"a"cycloidal
profile[2-4]ud
"PeterZeilfelder"Companyalsousa
similarprofile[5].The0'a"profileisdistir}g}zishedbyahighcircular
gearingfactor[5];thismakesitpossibletodesigngearshavingasmall
numberofteethwithalargerelativeheight(depthofthread),as
characterizedbytheratioDeID;(hereD}andD;,respectively,the
externalandinternaldiametersofthegearprofile),Inthatca,themass
andclearancedimensionsofthepumparereducedasaresultofarz
licalteeth,
whicharetreatedinthiscaasbeveledteethwithalargetaperangleare
ud,theentrappedvolumeiliminated,asaresultofwhichthepumps
mayoperateathighrotationalspeeds.
Theoretically,therewillbenoentrappedvolume,ifthereisa
gmentinthegearengagement,wheretlpereisnocontactbetweenthe
tice,theextenttowhichcontactpressureis
lostduringgearengagementdependsonthelengthofthegmentofgear
nethedegreeofcontactpressure
duringengagement,Ietusintroducetheconceptofaconditional
engageanent-pressurefaetor
coc
(1)
where}yo=2}rfistheangleofcircularoverlapofthegearing,fisa
coefficient,thevaluesofwhicharegiveni}n[}}forvariouscycloidal
engagements,f=arccos(1.25一..2}E2)/二foran}}ateprofile.,
E=2Del(De+}g)r=tai'/z+}IStileangularpitchofaconventionalcircular
gear,zisthenumberofgearteeth,and&=2}rLftistileturnangleofthe
generatrixofacirculargearforascrew(gear)withatraveltandIength
L.
consideringthedesignationsthatwehaveassignedandthe
equationsgivenin[6],
)
1
(2
t
L
zc
(2)
Conquently,thepressurefactor
tLz
f
c
1
(3)
Thebevel-toothengagementwillbetightwhen1
c
,i.e,when
oc
.
Usingexpression
(2),
zf
L
tt
1min
(4)
ItfoIiowsfromEq.(4)thatforatightengagement,thetaperangleofthe
teethonthecentroid
minmax
tDarctg
c
(5)
where2
iec
DDDare
cycloidalengagementwithan“a”profziewithaninvoluteprofile,we
fabricatedandtestedbevel-toothimpellerswithan"a"profile(eFig.1)
inanShF8-25pzzlllp;theimpellershavethefollowingparameters:
e
D=52mm,
i
D=36mm,acenter-to-centerspacingA=D
c
=44mm,
t=1000mm(angle
ithcycloidalengagement("a"profile):a,b)
bevel-tooth(D
e
of52and125mm,respectively,D
i
=36and65mm,z=7
and6,=
7.870126and16.6178020,t=1000mm);c)straight-tooth
(D
e
=125mm,
D
i
;=65mm,z=6,L=85mm).
ofinclineoftoothaxisofgear=7.8701260),gearwidth(lengthof
screw)L=70mm,andz=ca,thecircular-overlapfactor
ci
1.000731,theoveralloverlapfactor1.49,theconditional
engagement-pressurefactox
c
0.672,andthemaximumtaperangleof
thetoothonthecentroid,forwhichtightengagementispossible,
max
=0.01180.
Involuteengagementwithstraightteethimployedinthe
ries-producedShF8-25pump(z=10,modulusm=4mm,A=44mm,
e
D=52mm,and
i
D=34.75mm,i.e.,smallerbytworadialclearances
thanforan"a"profileinwhichthereisnoradialclearance).
Wealsocomparedtheprocedureofcuttinggearsbyadiskprofile
cutteronahigh-precisionWanderermachine,whichhasbeenadoptedfor
fabricationofthescrewsofthree-screwpumps,withtheconventional
rgy
characteristicsweremeasuredtoapressureofp=0.5MPaatarotational
gearspeedofn=1450rpm,oilviscosityv=7410-6m2/c,andsuction
headH
su
=lowingcharacteristicswereobtainedasaresultof
theinvestigation:forthe"a"profile一flowrateQ=6.6m3/h,power
consumptionN=1.58kW,overallefficiency=62.6%,bulkefficiency
m
=98.2%,andmechanicalefficiency}m=63.7;fortheimpellerswiththe
involuteprofile,whichwerefabricatedinaccordancewiththenew
technology一Q=6.5m3/h,N=1.43kW,=67.8%,
b
=94.8,and
m
=71.5%;and,fortheimpellersfabricatedinaccordancewiththe
conventionaltechnology一Q=6.1m3/h,N=1.4kW,=64.5%,
b
=88.4%,and
m
=73%.Asisapparent,
b
ofthe"a"profileissomewhat
higherthanthatoftheinvoluteprofile,whileand
m
aresomewhat
er
m
canbeexplainedbythepoorforcequalitiesofthe
"a"profileinwhichcontactoccursduetoslippageofthemidpointofone
profileovertheapexoftheother,andthepointoftheapexofoneprofile
roacousticcharacteristicsofthe
bevel-toothgearswiththe"a"profileareapproximatelythesameastho
ofthestraight-toothgearswiththeinvoluteprofile.
Thefollowingcharacteristicswereobtainedforthetestingof
bevel-toothgearswithan"a"profileinanNMSh8-25hydraulically
drivenpumpatn=1450rpm,=74
10-6m2/c,p=2.5MPa,andH
SU
=5
m:Q=5.31rn3/hand=79.2%.Theinvolute-gearpumphasQ=6.65m3/h
and=84.6%ingtoGOST19027一
89,Q=6.3m3/hand=81%fortheparameters.
TherequirementstforthbytheGOSTarethereforeobrvedin
tly,straight-toothgears,butwith
improvedforcepropertiesoverthoofthe"a"profilemustalsobeud
toachievetherequireddeliveryand,ofpumpswithgearshavinga
dalgearswiththesmallerdimensionsofthe
involutegearsudinriesproducedpumpswereemployedintesting
aoftheinvolutegears,z=I2,m=10mm,
A=130mm,D
e
=150mm,L=85mm,andthetaperangleofthe
bevel-toothgears,150;inthatca,159467.1
ci
,=1.884,
c
=0.672,and
max
=3.653.Asaresultofthepumptests,weobtained
Q=37.8rn3/h,=67.5%,、%1.91
b
,and%1.71
m
forageometric
deliveryQ
g
=42.51m3/h(19027一89,theNMSh
80-16pumpshouldhaveQ=36m3/h,=71.6%,andamassM=150kgat
n=980rpm,v=74
106m2/c,andp=1.6MPa.
ThedesignoftheNMSh80-16pumpwishstraight-and
bevel-toothgearshavingan"a"cycloidalprofileofsmallerdimensions
wasdevelopedonthebasisofthefollowingparameters:z=6,A=95mm,
D
e
=125mm,D
i
=65rnm,D
e
/D
i
=1.923,L=85mm,M=90kg,andt=1000
mm,i.e.,thehelixangleofthehelicallineD
C
=95mm,=73.3821980,
and=90=16.617802.Inthatca,
ci
=1.173235,and=1.683,
c
=0.777,and
max
=5.79
characteristics,apumpwithbevel-toothgearshasthefollowing
characteristics:Q=36.3m3/h,=63.4%,
b
=74.1%,and
m
=85.6%for
ageometricdeliveryQ
g
=49m3/h.t1sisapparent,
b
ofapumpwith
tlzesagearsislowerthanthatofapumpwithinvolutegears,butrlmis
nbeexplainedbythesmallerdimensionsofthegearing,
i.e.,ller-than-expectedvalueofnbis
chargegroove
shouldbemanytimeslargerthanfleetfortheinvolutegears.
Thestraight-toothgearsweretestedtop=0.8MPa,sincethegears
izeupathighpressureandn=980rpm..fitalowrotationalspeed,
operationispossibleathigherpressure,forexample,atn=160rpm,p=1.2
MPa,H
su
=
=48
10-6m2/c,theNMSh80-16pumphas
Q=6.4m3/h,
b
h=80,
m
=66%,and=52.8%.
BBF-typepumpsareudatamaximumpressureof0.6-1MPa
[1].Atthemost,theBBF3pumpforwhichQ=36m3/hand=71.3%
whenn=980rpm,=0.02m2/c,andp=0.8MPacorrespondstothe
tedatn=980rpm,=74
10-6m2/c,andp=0.8MPahavethefollowingcharacteristicswith
bevel-toothgears:Q=44.2m3/h,=72.4%,
b
=90.2%,and
m
=80.2%;andQ=45m3/h,=60.4%,
b
=91.8%,and
m
=65.8%with
straight-toothgears(Q=39.1m3/h,,=58.3%,
b
=94.3%,and
m
=61.
8%(forbevel-toothgearswithaninvoluteprofile).
Asisapparent,pumpqa}ippedwithbevel-toothgearswithan
"a"profilehaveaveryhighefficiencytoapressurep=0.8MPa;this
agreeswithexperiencegainedbytheFrenchfirm"Brine''[1].
TheGermancompany"PeterZeilfelder"ussix-toothgears
withaprofilethatlookslikean'a"profileinitsMehrflugelkolbenpumpen
loberotarypumps(multiplebladepistonpumps)withn=100-400rpmat
p2MPaandQ=1.5-240m3/umpsaredistinguishedbyavery
broadrangeofapplication,aresuitedespeciallyforthetransferofhighly
viscousliquids,anddevelophighpressureunderratherlowpulsation.
Two-toothimpellerswitha"d'profileareudindomesticloberotary
pumps[6].Significantpressurepulsations,whichwerenotedfromthe
fluctuationofthemanometerpointer,developedduringthetestingofa
KV0.7/18loberotarypumpwitha"d"profileatpp
impellershavethefollowingdimensions:D
e
=172mrn,D
i
=100mm,and
L=50mm;inthatca,thetheoreticaleffectivevolumepersingle
revolutionV=/4(D
e
2一D
1
2)L=0.76906liter/revolution,whilethe
theoreticaldelivery=0.06Vn=4.614m3/hatn=rmine
theeffectofsix-toothimpellersonliquidpulsationandpumpefficiency,
wetestedanNMSh80-16pumpatn=30-160rpmwhiletransferringa
liquidwithahighviscosity.
Accordingtotheformulascited,thetheoreticaleffective
volumeoftheNMSh80-16pumpV=0.76105liter/revolutionand
Q
t
=4.566m3/hatn=,thedeliveriesoftheKV0.7/I8and
NMSh80-16pumpsareapproximatelya;ingandNMSh80-I6
pumpwithasuctionheadatzeropressure,Q
g
=5m3/hwhenn=I00rpm.
Thisdeliveryerasadoptedasthegeometricdelivery,and,
correspondingly,Q
g
=49m3/hatn=uesobtainedwere
udincalculatingthebulkandmechanicalefficiencies
Thetestresultsindicatedthatthepressurepulsationsofthe
liquidareappreciablysmaller,=100
rpm,p=1.4MPa,H
su
=0,andtheviscosityoftheliquidc/102622m,
forexample,theKV0.7/18pumphavingtwo-toothimpellerswitha"d”
profilehasQ=2.18m3/h,anoverallefficiency=23%,abulkefficiency
b
=47.3%,andamechanicalefficiency
m
=48.6%,whiletheNMSh
80-16pumphavingsix-toothimpellers“a”profilehasQ=4.5m2/h,
=60%,
b
=90%,and
m
=66.7%whenn=100rpm,p=I.4MPawhen
=45
10-4m2/c,Q=3.4m3/h,=38%,
b
=68%arid
m
=55.9%
(bevel-toothgears).
Itisapparentfromthetestresultsthatpumpswith
straight-toothsix-toothimpellershavethehighestefficiency;intheca,
thepressurepulsationoftheliquidisappreciablylower;thisagreeswith
theresultsoftheGermanfirm[S].1tshouldbeconsideredherethatthe
efficiencyofalobe-rotarypumpwithsix-toothimpellerswillbe
somewhatlowerwithallowancefortheefficiencyofthe
synchronizing-geartransmission.
翻译:
当摆线轮廓用于大部分内容式叶轮机时,渐开线齿廓常使用于齿轮机械。最
近一些公司也开始使用摆线轮廓于齿轮泵。因此,公司制造的螺旋人
字齿齿轮泵的齿廓看上去像双螺杆泵的“a”型摆线齿廓。peterZeilfelder公司
也使用了类似的齿廓。“a”型轮廓是通过齿轮高度变位系数来确定的;因为
ie
DD/
的比率特征,就有可能设计出一个齿轮齿数少但相对高度大(深度线程)的齿轮
(这里的
e
D和
i
D分别指外齿轮和内齿轮的齿廓直径)。在这种情况下,泵的实体
和空隙的尺寸将因为齿轮的自由横截面积的增加而减小。当螺旋齿以斜齿大锥度
处理的种情况下,包络线容积被忽略,因此,齿轮泵将可能在高速旋转过程中运
行。
从理论上说,如果有部分齿轮啮合,有部分主动齿轮和被动齿轮没有啮合,
将不会有包络容积,在实践中,齿轮啮合过程中的接触压力的损失取决于齿轮未
啮合部分的长度,定义接触压力的啮合水平,我们将介绍条件接触压力因素的概
念:
cc
/
0
(1)
f2
0
是触动过程中部分重合圆的角度,
f
是系数,它的价值在于给出了各
种摆线的约束。对于“a”型曲线/25.025.1arccos2Ef,
iee
DDDE/2,
z
C
/2是常规圆柱齿轮角间距,z是齿轮齿数,tL/2是圆柱齿轮母
线转角。
考虑到我们的已经给出的定义给出方程:
t
L
zC
1
2(2)
因此,压力因素:
tLz
f
C//1
(3)
当1
C
时,斜齿轮传动将会被限制,即有当
0
C
时,使用表达(2):
zf
L
tt
/1min
(4)
他按照方程(4)严格啮合,在中心上的轮齿的锥度角为:
minmax
/tDarctg
C
(5)
2/
iec
DDD是直径,通过比较摆线啮合与渐开线“a”型曲面,我们装
配和测试锥齿叶轮机的“a”型曲面(图1)超高频8-25泵,叶轮参数为:mmD
e
52,
mmD
i
36,中心距为mmDa
c
44,mmt1000(齿轮轴的轮齿倾斜角
870126.7),齿轮宽度(螺旋线的长度)L=70mm,z=7。在这种情况下重合
度.1
ci
,但是总的重合度为49.1,跳进接触压力因子672.0
c
,
齿轮最大锥度在中心,因此完全可以无侧隙传动,0118.0
max
。
渐开线直齿啮合已经广泛应用与一系列超高频8-25系列产品(z=10,模数
m=4mm,A=44mm,D
e
=52mm,D
i
=34.76mm两个径向间隙相比,”a”曲面较小,
它没有径向间隙)。
我们还比较了在高精度硬齿面回转机上切割的齿轮与传统程序的滚刀切削
刀具切削,并试制了三螺杆泵。它的能量特性,在齿轮转速n=1450r/m的情况下,
测量出压力p=0.5MP,机油粘度ν=74x10-6m2/s水头高度为H
s
=5m。以下几个特
点是根据调查结果得到的:对于“a”型曲面,流量Q=6.6m3/h,功率消耗
N=1.58kw,总效率
%6.62,容积效率%2.98
b
,机械效率%7.63
m
;
对于叶轮为渐开线的齿廓,按照新技术修正得到,Q=6.5m3/h,N=1.43KW,
%8.67,%8.94
b
,%5.71
m
;按照叶轮的常规技术有,-Q=6.1m3/h,
N=1.4KW,
%5.64,%4.88
b
,%73
m
。可以看出,“a”型曲面的容积
效率比渐开线曲面的大,但总效率和机械效率低,机械效率低可以用“a”型曲
面的动力特性差。斜齿的“a”型曲面和直齿渐开线轮廓的振动特性基本相同。
以下几个特点是根据测试斜齿“a”型曲面在NMSH8-25液压马达中得到的,
其试验的条件为,n=1450r/min,v=74x10-6m2/s,p=2.5MPa,水头为5米,Q=5.31m3/h,
η=79.2%。渐开线齿轮泵Q=6.65m3/h,η=84.6%,在这个相同的参数下。根据
GOST19027-89知,Q=6.3m3/h,η=81%。
根据GOST的要求规定应注意应用渐开线轮廓,显然,在必须用来实现所
需的传动的摆线齿轮泵中,直齿比“a”型轮廓改善动力特性好。摆线齿轮和小
尺寸渐开线齿轮被用于一系列泵中并被要求按照NMSH80-16泵测试,在这种情
况下的渐开线齿轮,z=12,m=10mm,A=130mm,D
e
=150mm,L=85mm,并且
限制斜齿轮锥角15,此时,159467.1
ci
,884.1,653.3
max
。根据
泵测试的结果,我们注意到,hmQ/8.373,
%5.67,%1.91
b
,%1.71
m
。
由几何代换,
hmQ
g
/51.423
(根据GOST19027-89),NMSh80-16泵应该有,
当min/980rn,
smv/107426
,
MPap6.1
时,hmQ/363,
%6.71,
毛重M=150kg。
运用“a”型齿廓的直齿和斜齿设计的NMSh80-16泵结构尺寸更小巧的原
因基于以下参数:z=6,A=95mm,mmD
e
125,mmD
i
65,923.1/
ie
DD,
mmL85,
kgM90
,mmt1000,也即,螺旋线的螺旋角mmD
c
95,
382198.73,617802.1690,在这种情况下,对于斜齿轮
173235.1
ci
,683.1,777.0
c
,79.5
max
。根据这些特点,斜齿轮泵
有以下特性:hmQ/3.363,
%4.63,%1.74
b
,%6.85
m
,根据几何
原理,
hmQ
g
/493
,可以看出,运用该齿廓的泵比渐开线齿轮泵的
b
更小,
但是
m
缺更大,这可以用几何尺寸小来解释,也即,摩擦面积更小。
b
小于预
期值显然是因为齿轮加工导致的。排放槽应大于渐开线齿轮。
当直齿齿轮在n=980r/m下测试,压力可达到
Mpap8.0
.低速旋转,时,可
能实现更高的压力,例如,在mrn/160,
Mpap2.1
,mH
su
3,
smv/104826
时,NMSh80-16泵的hmQ/4.63,%80
b
,%66
m
,
%8.52。
BBF型泵最大可用压力为0.6~1Mpa,大多数情况下,BBF型泵的
hmQ/363,
%3.71,对应于NMSh80-16泵的参数为:min/980rn,
smv/02.02
,
Mpap8.0
。斜齿轮泵在min/980rn,
smv/107426
,
Mpap8.0
条件下测试,有以下特性:hmQ/2.443,%2.90
b
,%2.80
m
,
%4.72,直齿齿轮有:hmQ/453,%8.91
b
,%8.65
m
,
%4.60。
而在同样条件下的斜齿渐开线齿轮有:hmQ/1.393,%3.94
b
,%8.61
m
,
%3.58。
由此可见,将“a”曲面轮廓斜齿轮运用于泵中,在
Mpap8.0
时,效率将
非常高。这和法国“Brire”公司所取得的经验是相一致的。
德国“PeterZeilfelder”公司在Mehrflfigelkolbenpumpen叶片旋转泵(多叶
片柱塞泵)中使用了带有“a”型曲面的六齿齿轮,它的转速为min/400~100rn,
压力
Mpap2
,流量hmQ/240~5.13。这些泵的特点就是应用广泛,可适用
于各种液体,和高压力、低脉动场合。“d”型曲面双齿叶轮。
被应用于内旋式叶片泵。波动的压力表指针昭示了巨大的压力脉动,在
Mpap1
时,对有“d”型曲面的KV0.7/18叶片转子泵进行测试。改泵的叶轮
有以下尺寸:mmD
e
172,mmD
i
100,mmL50。在这样的情况下,每转
一周的理论容积效率rLLDDV
ie
/76906.04/22,而理论输出流量
min/100/614.406.03rhmVnQ
t
。为了确定六齿叶轮对液体脉动和泵的效率
的影响,我们对NMSh80-16泵在n=30-160转速输送高粘度液体进行了测试。
根据引用的公式可知,在min/100rn的条件下,NMSh80-16泵的理论容
积效率为rLV/76105.0,输出流量hmQ
t
/566.43。因此,KV0.7/18泵和NMSh
80-16泵的输出量基本一致。测试NMSh80-16泵在吸入压力为零min/100rn时,
hmQ
g
/53
。这个排量将作为几何排量,相应地,min/980rn时,
hmQ
g
/493
,
其价值在于优化结构体积和机械效率。
测试结果表明,液体的压力脉动略微小一点,但是六齿叶轮泵的更高。当
min/100rn,
Mpap4.1
,0
su
H,液体的流速
smv/102622
时,例如,
带“a”型曲面的KV0.7/18双叶片泵为直齿齿轮min/100rn,
Mpap4.1
,
0
su
H和
smv/103122
时,
hmQ/18.23
,总效率
%23,体积效率
%3.47
b
,机械效率%6.48
m
,同样的斜齿轮在
smv/104522
时,
hmQ/4.33
,%68
b
,%9.55
m
,
%38。
显然,从测试的结果看带有直齿六齿叶轮的泵效率最高。此时,它的液体压
力脉动也较低;这个结果和德国公司的结论也相一致。因此,可以认为带六齿叶
轮的回转叶轮泵效率比齿轮同步传动的效率更低。
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