1 development of 3-d simulation for power transmitting analysis of cvt driven by dry hybrid v-belt...
TRANSCRIPT
1
Development of 3-D simulation for power
transmitting analysis of CVT driven by dry
hybrid V-belt
Development of 3-D simulation for power
transmitting analysis of CVT driven by dry
hybrid V-belt
Masahide FUJITA Hisayasu MURAKAMI Power Train Research and Development DivisionDaihatsu Motor CO., LTD.
Shigeki OKUNO Mitsuhiko TAKAHASHI Power Transmission Technical Research Center
Bando Chemical Industries, LTD
International Continuously Variable and Hybrid Transmission Congress
September 23-25, 2004
San Francisco, CA
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BackgroundNew CVT3D-simulationOutcomes
Transmitting efficiencyDynamic strain on the belt
Conclusions
ContentsContents
3
Main products of Daihatsu: Small-sized Cars
BackgroundBackground
1L 2L
Application
Metal pushing V-belt
Engine displacement
Excessive quality
Commercialized CVT
New CVT
Higher efficiency
Dry hybrid V-belt
4
Blocks (Resin coated aluminum alloy)
Tension bands
Aramid cord Rubber
New CVT with Dry Hybrid V-beltNew CVT with Dry Hybrid V-belt
Advantage:Air coolingNo lubricant
=Higher efficiency
High torque capacity with improved wider belt=Increased belt mass / inertia
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MeritIncrease contact angle
Torque capacity rise
Belt tension controlBetter efficiency
Driving Pulley
Driven Pulley
Tension Pulley
DemeritReverse bending force
Less durability
New CVT systemNew CVT system
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Driving Pulley
Driven Pulley
3800rpm 30m/s
3-D dynamic simulation3-D dynamic simulation
Belt movement in high speed:
Dynamic measurements is impossible 3-D dynamic FEA is needed
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Required features:Precise inertia force calculationAdvanced contact searchDynamic belt behavior visualization (stress & others)
Explicit FEM codeESI Software's PAM-MEDYSA
(MEchanical DYnamic Stress Analysis)
Selection of FEM codeSelection of FEM code
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Building the model as it isCord anisotropyContacts defined between block & tension band
BlockRubber
Resin
Upperbeam
Lowerbeam Cord
Tension band
Aluminum
Modeling of dry hybrid V-beltModeling of dry hybrid V-belt
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All parts: Defined as elasticComponents of pulley shaft
Sliding interface taking account of shaft clearance
Fixed pulleyMovable pulley
Fixed pulley shaftw/ clearance
Resin bush
Slide keys
Modeling of CVT pulleysModeling of CVT pulleys
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1. Initial state (Belt: Tension free)
2. Move driving pulley (apply tension to the belt)
3. Rotate driving pulleyApply absorbing torque
Driving pulley Driven pulley
Calculation proceduresCalculation procedures
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Calculation procedures: movieCalculation procedures: movie
12Belt velocity (m/s)
Effi
cie
ncy
(%)
Transmitting efficiencyAt high speed running: lower efficiency Difference (simulation/experiment): 2%
All Parts: elastic
Calculated
Measured
949596979899
100
0 10 20 30 40
2%
Ratio : High (0.407) Input torque : 80Nm
Outcome on initial modelOutcome on initial model
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949596979899
100
0 10 20 30 40
Belt velocity (m/s)
Effi
cien
cy (%
) Calculated
Measured
Ratio : High (0.407) Input torque : 80Nm
Matching of simulation with measurement Solutions:
Take account of friction loss at pulley shaft Increase friction loss between belt and pulleys
Fixed pulley
Movable pulley
Pulley shaftw/ clearance Resin bush
Slide keys
Outcome from improved modelOutcome from improved model
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Clearance between tension band and block
From heat aging
Decrease transmitting efficiency
Belt temperature rise
At final period of belt lifespan:
Permanent deformation of tension bandPermanent deformation of tension band
=
15
90
92
94
96
98
100
0 0.1 0.2 0.3
Clearance (mm)
Effi
cie
ncy
(%
)
Vehicle speed 60Km/h
123Km/h
148Km/h
173Km/h
with belt speed 30m/s
with belt speed 35m/s
Vehicle speed 60Km/h
Effect of permanent deformation Effect of permanent deformation
Calculation result of clearance vs. transmitting efficiency
Final period of lifespan
1.45kw power loss +18 %1.72kw
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At high speed rangeIncrease clearance
Decrease efficiency
Efficiency lowed within 1%Power loss +18%
Belt temperature rise
Effect of permanent deformation Effect of permanent deformation
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At the period of lifespanCrack at lower side of tension bands
Dynamic FEACalculate lower side strain
at higher belt speed
crack
Dynamic strain analysisDynamic strain analysis
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Period of contact with tension Pulley
Str
ain Bending
Strain
Strain Peak in dynamic behavior
0
Belt speed: 35m/s 9.7m/s
Strain peak at tension pulleyStrain peak at tension pulley
Ratio:High (0.407) Low (2.449)
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0
1
2
3
4
5
6
7
8
9
10
11
12
0 5 10 15 20 25 30 35 40
ベルト速度 (m/s)
下コク
゙表面
歪み
(%
)
Strain by dynamic behaviorproportional to Belt Speed squared
calculated strain
Strain in dynamic behavior
S=0.00177*V2+7.96
Ten
sio
n b
an
d
str
ain
(%)
Ben
din
g s
train
Strain analysis at tension pulleyStrain analysis at tension pulley
Belt speed(m/s)
20
8
9
10
11
12
13
14
1.00E+07 1.00E+08 1.00E+09Number of cycles to crack failure
Maxim
um
str
ain
of
tensi
on b
and (
%)90℃100℃110℃120℃130℃140℃
Belt temperature rise
Belt speed increase
Crack failure S-N curve Crack failure S-N curve
S
trai
n (
%)
Number of cycles to crack
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Based on S-N curve and calculated strainFull agreementFull agreement
Decrease velocity longer belt life
Prediction of belt lifePrediction of belt life
Velocity of belt(m/s)
Belt
life
(hr)
Exp
erim
ent
Cal
cula
ted
Cal
cula
ted
Exp
erim
ent
Belt temperature : 130deg C
30m/s 35m/s
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Factors to affect transmitting efficiency:Pulley shaft clearancePermanent deformation of tension band
Friction loss = Lower efficiency at high belt speed
Raise belt temperature
Shorten belt life
Dynamic strain at high belt speed Shorten belt life
Keys to successCooling systemLimit the maximum belt speed
ConclusionsConclusions