experimental and numerical analysis of automotive gearbox ...€¦ · idle gear dynamics...
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![Page 1: Experimental and numerical analysis of automotive gearbox ...€¦ · Idle gear dynamics Experimental and simulated relative velocities rpm) (m/s) (m/s) Ω = 750 rpm et A = 125 rpm](https://reader035.vdocuments.net/reader035/viewer/2022081622/613c085cf8f21c0c82695748/html5/thumbnails/1.jpg)
Experimental and numerical analysis of
automotive gearbox rattle noise
Younes KADMIRI
Emmanuel RIGAUD, Joël PERRET-LIAUDET
Journées GDR Visible, 18-19 mai 2011, IFSTTAR, Bron
![Page 2: Experimental and numerical analysis of automotive gearbox ...€¦ · Idle gear dynamics Experimental and simulated relative velocities rpm) (m/s) (m/s) Ω = 750 rpm et A = 125 rpm](https://reader035.vdocuments.net/reader035/viewer/2022081622/613c085cf8f21c0c82695748/html5/thumbnails/2.jpg)
Introduction
Improving acoustic confort
External noise sources:External noise sources:
- Aerodynamic
- Pneumatic
Introduction Numerical model Idle gear dynamics Housing vibration Conclusion
![Page 3: Experimental and numerical analysis of automotive gearbox ...€¦ · Idle gear dynamics Experimental and simulated relative velocities rpm) (m/s) (m/s) Ω = 750 rpm et A = 125 rpm](https://reader035.vdocuments.net/reader035/viewer/2022081622/613c085cf8f21c0c82695748/html5/thumbnails/3.jpg)
Introduction
Improving acoustic confort
External noise sources:External noise sources:
- Aerodynamic
- Pneumatic
Internal noise sources:
- Engine
- Gearbox
(gear whine, rattle noise)
Engine GearboxIntroduction Numerical model Idle gear dynamics Housing vibration Conclusion
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Kinematic scheme of TL4 gearbox
Introduction
Idle gearsDriving gears and shaftsSynchronizing systemDifferentialHousing
Introduction Numerical model Idle gear dynamics Housing vibration Conclusion
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123
564
Introduction
Differential
Configuration : Neutral
Introduction Numerical model Idle gear dynamics Housing vibration Conclusion
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123
564
Introduction
DifferentialDifferential
Configuration : 3rd gear ratio engaged
Introduction Numerical model Idle gear dynamics Housing vibration Conclusion
![Page 7: Experimental and numerical analysis of automotive gearbox ...€¦ · Idle gear dynamics Experimental and simulated relative velocities rpm) (m/s) (m/s) Ω = 750 rpm et A = 125 rpm](https://reader035.vdocuments.net/reader035/viewer/2022081622/613c085cf8f21c0c82695748/html5/thumbnails/7.jpg)
Ve
loci
ty
Introduction
2500
2600
Ve
loci
ty
Four-cylinder four stroke engineTime
2400
Introduction Numerical model Idle gear dynamics Housing vibration Conclusion
![Page 8: Experimental and numerical analysis of automotive gearbox ...€¦ · Idle gear dynamics Experimental and simulated relative velocities rpm) (m/s) (m/s) Ω = 750 rpm et A = 125 rpm](https://reader035.vdocuments.net/reader035/viewer/2022081622/613c085cf8f21c0c82695748/html5/thumbnails/8.jpg)
Housing vibrationOperating conditions
Rattle noise
Idle gear dynamics
Vibration transfer(shaft, bearings)
Housing vibration- Operating speed
- Drag torque
- Contact stifness/damping
Excitation sourceDesign parameters
- Idle gears inertia
- Backlashes
Introduction Numerical model Idle gear dynamics Housing vibration Conclusion
![Page 9: Experimental and numerical analysis of automotive gearbox ...€¦ · Idle gear dynamics Experimental and simulated relative velocities rpm) (m/s) (m/s) Ω = 750 rpm et A = 125 rpm](https://reader035.vdocuments.net/reader035/viewer/2022081622/613c085cf8f21c0c82695748/html5/thumbnails/9.jpg)
Numerical model
Excitation sourceVelocity fluctuation
- Idle gears dynamics
- Impacts time history
- Transmitted forces
Housing vibration
- Operating conditions
- Design parameters
Impulse response
Rattle noise
characterization
Housing vibrationImpulse response
Renault criterion
Introduction Numerical model Idle gear dynamics Housing vibration Conclusion
![Page 10: Experimental and numerical analysis of automotive gearbox ...€¦ · Idle gear dynamics Experimental and simulated relative velocities rpm) (m/s) (m/s) Ω = 750 rpm et A = 125 rpm](https://reader035.vdocuments.net/reader035/viewer/2022081622/613c085cf8f21c0c82695748/html5/thumbnails/10.jpg)
x(t)
y2(t)
Non linear model
Angular displacement Displacement along the action line
mx(t)
F
y1(t)
y2(t)
Free fligth
y2(t)
Permanent contact Impacts
y2(t)
Fxm −=&&F
m x(t)
y2(t)
y1(t)
)()(0 11 tymFtR &&+=<)()(0 22 tymFtR &&+=>
F
mx(t)
y1(t)
)()( −−++ −−=−iiyxryx &&&&
10 ≤≤ r
F
mx(t)
y1(t)
Introduction Numerical model Idle gear dynamics Housing vibration Conclusion
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Dimensionless non linear model
6 variables necessary to describe rattle noise
(m, F, r, H, j, ω)(m, F, r, H, j, ω)
Vaschy-Buckingham
theorem
3 dimensionless numbers
F
mH2ω=Λ
H
jj =~
r
Introduction Numerical model Idle gear dynamics Housing vibration Conclusion
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Time responses for
yx ~,~yx ~,~
Λ = 1,1
85.0,8~ == rj
Λ = 1,5
yx ~,~yx ~,~
Λ = 1,1 Λ = 1,5
t~
t~
Λ = 2,5 Λ = 3,5
Introduction Numerical model Idle gear dynamics Housing vibration Conclusion
![Page 13: Experimental and numerical analysis of automotive gearbox ...€¦ · Idle gear dynamics Experimental and simulated relative velocities rpm) (m/s) (m/s) Ω = 750 rpm et A = 125 rpm](https://reader035.vdocuments.net/reader035/viewer/2022081622/613c085cf8f21c0c82695748/html5/thumbnails/13.jpg)
Active flank
Impulses diagram
B: rebounds and contact intermittency
I~ C: chaotic response
Reverse flank
Λ
D: 2T 2 impacts response
E: 1T 2 impacts response
Introduction Numerical model Idle gear dynamics Housing vibration Conclusion
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Conclusion
Restitution coefficient
Numerical model
Spectral content of
Λ parameter (m, H, F, ω)
Gear backlash
Spectral content of
velocity fluctuation
Measuring these parameters is necessary
Introduction Numerical model Idle gear dynamics Housing vibration Conclusion
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Test bench (BACY)Experiments performed :
• Key parameters measurement (restitution coeff., drag torque, …)
• Idle gear dynamics measurement• Idle gear dynamics measurement
• Housing vibration measurement
• Radiated noise measurement.
Introduction Numerical model Idle gear dynamics Housing vibration Conclusion
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Gearbox instrumentation
• Weak dimensions
• Small gear backlash = 0.1 mm
• Idle gear and supporting shaft are indepedant
• Severe operating conditions (high Ω, oil churning, high T, ...)• Severe operating conditions (high Ω, oil churning, high T, ...)
Optical encoder on driving gear
Driving gear
Configuration : 2nd, 3rd and 4th gear ratioConfiguration : 2nd gear ratio
Optical encoder on idle gear
Idle gear
Introduction Numerical model Idle gear dynamics Housing vibration Conclusion
![Page 17: Experimental and numerical analysis of automotive gearbox ...€¦ · Idle gear dynamics Experimental and simulated relative velocities rpm) (m/s) (m/s) Ω = 750 rpm et A = 125 rpm](https://reader035.vdocuments.net/reader035/viewer/2022081622/613c085cf8f21c0c82695748/html5/thumbnails/17.jpg)
Idle gear dynamics
T
Experimental and simulated relative velocities
rpm
)
(m/s
)
(m/s
)
Ω = 750 rpm et A = 50 rpm
Neutral T
Experimental and simulated Poincaré maps
(rp
m
(m/s
)
(m/s
)Time (s) Time (s)
/s)
Time (s)
Φ : phase (s)
ti : Impact time
T : period
[ ]Ttii
=Φ
Φ (s) Φ (s)
I(k
g.m
/s)
I(k
g.m
/s)
Introduction Numerical model Idle gear dynamics Housing vibration Conclusion
![Page 18: Experimental and numerical analysis of automotive gearbox ...€¦ · Idle gear dynamics Experimental and simulated relative velocities rpm) (m/s) (m/s) Ω = 750 rpm et A = 125 rpm](https://reader035.vdocuments.net/reader035/viewer/2022081622/613c085cf8f21c0c82695748/html5/thumbnails/18.jpg)
T
Idle gear dynamicsExperimental and simulated relative velocities
Rp
m)
(m/s
)
(m/s
)
Ω = 750 rpm et A = 100 rpm
NeutralExperimental and simulated Poincaré maps
(Rp
m
(m/s
)
(m/s
)Time (s) Time (s)
/s)
Time (s)
Φ : phase (s)
ti : Impact time
T : period
[ ]Ttii
=Φ
Φ (s) Φ (s)
I(k
g.m
/s)
I(k
g.m
/s)
Introduction Numerical model Idle gear dynamics Housing vibration Conclusion
![Page 19: Experimental and numerical analysis of automotive gearbox ...€¦ · Idle gear dynamics Experimental and simulated relative velocities rpm) (m/s) (m/s) Ω = 750 rpm et A = 125 rpm](https://reader035.vdocuments.net/reader035/viewer/2022081622/613c085cf8f21c0c82695748/html5/thumbnails/19.jpg)
Idle gear dynamicsExperimental and simulated relative velocities
rpm
)
(m/s
)
(m/s
)
Ω = 750 rpm et A = 125 rpm
3rd ratio engagedExperimental and simulated Poincaré maps
(rp
m
(m/s
)
(m/s
)Time (s) Time (s)
/s)
Time (s)
Φ : phase (s)
ti : Impact time
T : period
[ ]Ttii
=Φ
Φ (s) Φ (s)
I(k
g.m
/s)
I(k
g.m
/s)
Introduction Numerical model Idle gear dynamics Housing vibration Conclusion
![Page 20: Experimental and numerical analysis of automotive gearbox ...€¦ · Idle gear dynamics Experimental and simulated relative velocities rpm) (m/s) (m/s) Ω = 750 rpm et A = 125 rpm](https://reader035.vdocuments.net/reader035/viewer/2022081622/613c085cf8f21c0c82695748/html5/thumbnails/20.jpg)
Model outputs
Housing vibration
Successive impulses
Model outputs
Time response
Housing responseMeasured transfer fonction
Housing response
Introduction Numerical model Idle gear dynamics Housing vibration Conclusion
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Exp
eri
me
ntsΩ=750 rpmHousing vibration
A=50 rpm A=75 rpm A=100 rpm
Exp
eri
me
nts
Sim
ula
tio
n(m
/s²)
Time (s) Time (s)Time (s)
Sim
ula
tio
n(m
/s²)
Introduction Numerical model Idle gear dynamics Housing vibration Conclusion
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Renault Criterion «5 faces»
Ω=500, 750, 1000 rpm
«5
fa
ces»
(d
B)
Experiments / Simulated
«5
fa
ces»
(d
B)
Cri
teri
on
«5
fa
ces»
(d
B)
A (rpm)
Cri
teri
on
«5
fa
ces»
(d
B)
A (rpm)
A 50 rpm 75 rpm 100 rpm 125 rpm
Experiments 16,4 dB 18,6 dB 19,5 dB 20,9 dB
Simulation 14,9 dB 17,6 dB 18,6 dB 20,6 dB
Error 1,5 dB 1,0 dB 0,9 dB 0,3 dB
A (rpm) A (rpm)
Introduction Numerical model Idle gear dynamics Housing vibration Conclusion
![Page 23: Experimental and numerical analysis of automotive gearbox ...€¦ · Idle gear dynamics Experimental and simulated relative velocities rpm) (m/s) (m/s) Ω = 750 rpm et A = 125 rpm](https://reader035.vdocuments.net/reader035/viewer/2022081622/613c085cf8f21c0c82695748/html5/thumbnails/23.jpg)
- Experiments performed with BACY allowed non linear numerical model.
- Operational software.
- Rattle noise can be predicted for:
Conclusion
- Rattle noise can be predicted for:
• any gearbox,
• any gear ratio,
• any operating conditions.
- Parametric studies allow gearbox design optimization.
Ω=750 rpm, A=75 rpm Ω=750 rpm, A=125 rpm
Backlash (µm)
«5
fa
ces»
(d
B)
Backlash (µm)
«5
fa
ces»
(d
B)