RotasPro Gear Test and Noise Analysis - Discom · PDF fileRotasPro Gear Test and Noise...
Transcript of RotasPro Gear Test and Noise Analysis - Discom · PDF fileRotasPro Gear Test and Noise...
2.10.2007
MTE Analysis of Gears
RotasPro Gear Test and Noise Analysis
2.10.2007
The company was founded in 1985. It is situated in Göttingen in the heart of Germany. Since 1989 the main product are measurement system for the acoustical quality analysis. There are 24 employees and more than 400 test systems deployed.
Base system are ROTAS and MESAM-4 (a joint development with DaimlerChrysler). Build on top of them are APAS for the cabin noise analysis, ROTAS-GP for the analysis of gearboxes and transmissions, ROTAS-ZP for the gear test, ROTAS-TMO for the test of tapered roller bearings.
MESAM 4
APAS-II
Base System Gearboxes and ComponentsCabin noise
ROTAS-Mobil
Discom Industrial Measurement Inc.
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ZF DGear Testers 4 Systems
Volkswagen D,SA,AR, China,B,SK,BRGearboxes, Transmissions, Gear Testers, Cabin Noise Production Database, 165 Systems
Tongil, KoreaAxles, Durability test Stand, 1 System
SFT, Magna Stey PowertrainAxles and gearboxes 28 Systems
Skoda, CzGearboxes, 7 Systems
SAIC Shanghai Automobile InternatiolCorp.Gearboxes test systems, 4 Systems
SKF D, USA, India, UkraineTapered Roller Bearings, 26 Systems
Robert Bosch Starters, injection pumps, production database 6 Systems
Renault, PeugeotTransmissions, 5 Systems
GM, USA, Opel D and AGearboxes 14 Systems and Axle Testers 25 Systems
Jatco, JapanCVT Transmissions
Discom: Customers and Applications
Fiat, Iveco, TataManual Transmissions 7 Systems
Getrag, USA Sc, Single Flank Gear Tester for Cummins Engine Gears with Tors. Acceleration
Graziano, Italy Gearboxes and Axles for Audi, Aston Martin, Ferrari, Lamborghini, Maserrati
Gearbox, SPgearboxes, gear testers 12 Systems
Ford, DGear Testers 4 Systems
First Automobile Works, ChinaGearboxes 1 System
DaimlerChrysler D, US Cooperation MESAM4, gearboxes, transmissions and engines. 36 Systems
Borg-Warner, USA,UK Transmissions und Axles 8 Systems
Bentley, UKCabin Noise Analysis APAS, 2 Systems
American Axle, USAFront and Rear Axles, 5 Systems
Hyundai, KoreaGear tester 2 Systems
Cummins
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MTE/Torsional Acceleration Measurement
n
M
3000
0
0
50 60 70 80 90 100 110 120 130 Ord
40
50
60
70
80
dBV
Mix
Antrieb
GM
2 *GM
GhostOrders
Test Sequence is steady speed or ramp
Mechanical Layout of Test MachineRotas NVH Analysis
TorsionalAccelerometer
40 Nm 10-40 Nm
Tested Gear
t
t
15-20 s
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Revolution Synchronous Transmission Analysis
Input Shaft Interm. Shaft Output Shaft
The transmission noise is the sum of the noise originating from the individual mechanical components.
For the gear noise components, the individual sources can be isolated by the transmission ratio.
Synchronousorder analysis:The signals are acquired synchronousto the inner shafts.AcousticalStroboscope
Input Shaft
Interm. Shaft
Output Shaft
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400 800 1200 1600 2000 2400 2800 3200 3600m Rev
-16.0
-8.0
0.0
8.0
16.0
g
ZwAn
-16.0
-8.0
0.0
8.0
16.0
g
ZwAb
-16.0
-8.0
0.0
8.0
16.0
g
TsAb
Synchronous Averaging II
Nicks are shown in the synchronous channel that is synched with the offending shaft.The nick detection is based on the Crest value
Crest = Peak value/RMS value
AG4 V4.0 Typ 39 Unit 67 04.Jun'2000,17:10:16-------------------------------------------------------------------Code Description Gear Is Lim Av Unit Kx448 NICK 3.-Gear / Up 3-Z 16.8/ 12.0/ 9.5 Crest ZwAn--------------------------------------------------------------------
AG4 V4.0 Typ 39 Unit 67 04.Jun'2000,17:10:16-------------------------------------------------------------------Code Description Gear Is Lim Av Unit Kx448 NICK 3.-Gear / Up 3-Z 16.8/ 12.0/ 9.5 Crest ZwAn--------------------------------------------------------------------
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Torsional Accelerometer
gez.:J. Lorenz
Rotierender SensorAbmaßeAluminium/Kunsstoff
ZEICHN.NR.041220-0MASSTAB 1:1 2004-12-20
BLATT 1 von 1
DIS COMMATERIAL:
Tel=0551/548330Fax=0551/5483343
Sender
Empfänger
Lagergehäuse
20,0
0
Ø70,00
Ø22,00
Øyxx
38,00
32,0
0
Sensor
110,
00
125,00
35,00
25,00
45,0
0
90,0
0
10,00 10,00
Rotational ensorAccelerometers
LED Sender
Optical Receiver Power TransformerInto Rotator
gez.:J. Lorenz
Rotierender SensorEmpfänger- Gehäuse
AluminiumZEICHN.NR.050103-6MASSTAB 1:1 2005-01-03
BLATT 1 von 1
DIS COMMATERIAL:
Tel=0551/548330Fax=0551/5483343
90,00
35,00
110,
0090
,00
R 12,00
R 14,00
R 13,00R 16,00
R 2,00
Nut 1x2
Nut 2x2
35,0
0
24,0
0
2,50
10,0010,00
10,0
010
,00
4x d=5,1
R 4,00
2x M2,5
30,0
0
5,00
Deckel 10x34,8x5
R 35,00
Nut 1x2
30,0
0
2x Bohrung u. Senkung M2,5
1,002,005,00
20,0
0
10,0
0
Ansicht von oben
2,50
53,00
10,00
3,00
3,00
18,5
0
R 35,00
R 32,50
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Torsional Accelerometer
Rotating Sensor
Accelerometers measure the deviation from uniform circular motion
Optical SenderOptical Receiver Power TransformerInto Rotator
Accelerometers
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Test gear
Master Gear
Torsional Accelerometer
Single Flank Gear Tester Linnenbrink
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Engine Gear Tester Getrag / Cummins
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Results from Crank/Cam Gear pairs
0.00.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 Rev
V.V
-0.3
-0.2.-0.2
-0.1.-0.1
0.0.0.0
0.1.0.1
0.2.0.2
Crank
0.00.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 Rev
V.V
-0.3
-0.2.-0.2
-0.1.-0.1
0.0.0.0
0.1.0.1
0.2.0.2
Cam_Shaft
0.00.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 Rev
V.V
-0.3
-0.2.-0.2
-0.1.-0.1
0.0.0.0
0.1.0.1
0.2.0.2
Crank
0 00 0 0 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 Rev
V.V
-0.3
-0.2.-0.2
-0.1.-0.1
0.0.0.0
0.1.0.1
0.2.0.2
Cam_Shaft
Good Gear Set
Crank Gear
Cam Gear
0.00.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 Rev
V.V
-0.24
-0.16.-0.16
-0.08.-0.08
0.00.0.00
0.08.0.08
0.16.0.16
Crank
0.00.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 Rev
V.V
-0.24
-0.16.-0.16
-0.08.-0.08
0.00.0.00
0.08.0.08
0.16.0.16
Cam_Shaft
Eccentricity onCam Gear
Nick on Cam Gear
Graphs show one revolution of the crank and the cam gear when run as pairs on the single flank gear tester. The faults can be easily detected.
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Comparing DIN 3960 composite inspection
Fi’ tangential composite deviationLong wave component
Fi’Fi’
fk’ tooth to tooth deviationshort wave component
fk’ fk’
Good Gear Set Eccentricity onCam Gear
Graphs show one revolution of the cam gear when run as pairs on the single flank gear tester. The good and the bad gear set show less variation with this method. Fi’ is even smaller for the bad gear
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Separation of Gear Errors
The acoustical signal holds the components of both gears.
Knowing the transmission ratio, the periodicity of each gear can be found. Gear mesh components only depend on the pairing of the gears.
Eccentricities and surface errors can be separated because they have a cycle that corresponds to the originating gear. The following errors can contributed individually:
� Eccentricities, � Deviation from circular shape� Tooth spacing� Surface waves (Ghost Orders)� Nicks
Z1
16
Z2
20
Z1
16
Z2
20
The gear mesh componentdepends on the pairing
Eccentricities and surfaceerrors can be contributedindividually.
16
20
16
20
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50 60 70 80 90 100 110 120 130 Ord
40
50
60
70
80
dBV
Mix
Antrieb
Revolution synchronous averaging gives periodic (cyclic) signals. This corresponds to the cyclic nature of the gear sets.
These signals can be transformed into the spectral domain without any time domain leakage windows.
This allows for high spectral resolution. Eccentricities can be easily distinguished from the gear mesh orders. The noise components can be attributed to their origins.
Blue: Conventional order spectrum with Kaiser Bessel Window
Green: Revolution synchronous order spectrum without window function
Synchronous Averaging III
GM 2 *GM
Ecc.. GhostOrders
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Results from Single Flank Gear Tester
und PrüftechnikIndustrielle Meß-
Crank No 30-4005.04.05 10:19
0 20 40 60 80 100 120 Ord 10 15 20 25 30 35 40 45 50 55 60 65
dBV
Spectra / Pz1 / SK1 / SpecReport
0 40 80 120 160 200 240 Ord 10 15 20 25 30 35 40 45 50 55 60 65
dBV
Spectra / Pz1 / SK2 / SpecReport
0 20 40 60 80 100 120 Ord 10 15 20 25 30 35 40 45 50 55 60 65
dBV
Spectra / Pz2 / SK1 / SpecReport
0 40 80 120 160 200 240 Ord 10 15 20 25 30 35 40 45 50 55 60 65
dBV
Spectra / Pz2 / SK2 / SpecReport
Drive Coast
Crank
Cam
H1 H2
H3
Various filed units shown as stray bands. The gear mesh energies are clearly seen.
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Evaluation of Order Spectra
10 20 30 40 50 60 70 80 90 Ord
45
60
75
90
105
dBgVGW
VGW-lim
The order spectra of the synchronous channelsand of the mix channel are compared with a
limit curve. Every order of the limit curvehas an underlying error code. This error codeis generated from transmission ratios in a semiautomatic fashion. If the limit curveis exceeded, the error code gives rise to anerror message in plain text.
The limit curves consist of portions, whichare generated by a learning process and ofportions which are set to fixed values.
The learn rnode is used for those spectralportions, where there are results from driving experiments available yet. Generally thisholds true for tooth spacing problems,ghost orders and bearing noise (in themix channel).Fixed limits are adopted from driving experiments,usually for the gear mesh and for the side bands.
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10 20 30 40 50 60 70 80 90 Ord
20
40
60
80
100
dBg
MaxBnd
MinBnd
StdDev
AW-avg
SK1-lim
Spectral Limits
Limit curve from Average + Offset + n times standard deviation. Overridden by minimum and maximum polygons and by the fixed hats.
Hats for gear mesh orders and their side bands
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Learning
For all measurements, the following statisticalproperties are computed:
Average (AV) undStandard deviation (STD)
From these numbers, a limit L is generatedaccording to
L = AV + Offset + n* STD.
The offset and the multiplier of the standard deviation is selectable. For spectral measures,an offset of 5 dB and a std-factor of 3 is normally used. Maximum and minimum values set upper and lower bounds for the limit L.
A new learn consist of a base learn (usually 5 units), where all units are accepted that are below maximum polygons and below hats.
The base learn is followed by an additional learning (usually 100 units). Here every unit is evaluated against the already established limitcurves. Only error free units will be added to the learning sample.
Another available choice consists of a indefinite learn process with a selectable time constant.
During the whole learning process, the fixed limits apply. This assures, that all known data (like limits from car experiments) will be used as a guidance during the process.
What is learned Learning methods
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Intranet Statistics
The information of the SQL measurement database can be retrieved via the intranet.
The production results and the measurements can be seen online.
An arbitrary time interval can be selected for the analysis.
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Reject Analysis, Top n and Type Specific
The results are shown both in tabular and in graphical form
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Measurement Statistics and Bench Comparison
Over 300 individual measurement results can be evaluated.
The comparison of test benches makes it easy to administer large production facilities.
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Order spectra of production units can be displayed in Campbell or in 3-D graphs. Cuts in the order or in the unit direction show order amplitude versus units or the spectrum of one unit. The pictures show the order spectra of 300 production units. A ghost order of 118 is present in the first 40 units tested.
Spectral Statistics
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Cabin noise components
Noise sources
There are many different transfer paths for the sound and the vibration from the gearset to the drivers ear.
Each path has its own frequency dependent transfer function
Noise from the motor, wind and tires may mask certain frequency bands from the gears.
These effects induce the speed, torque and vehicle dependent noise perception of the gear sets.
Transfer paths
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Order spectrograms
Order spectrograms are recorded for the gearbox vibration signal and for the cabin sound field.
From these order tracks for arbitrary orders and order spectra for arbitrary speeds can be generated:
1) Ordnungs-Spektrogramm 4. Gang Zug
Order track for the 65. order
2) Order spectrum at 2241 RPM
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Vehicle: Accelerometer at Gearbox and Sound in Cabin