1. RotasPro Gear Test and Noise Analysis
Torsional Analysis of Single Gears

2. MTE/Torsional Acceleration Measurement
Mechanical Layout of Test Machine
Rotas NVH Analysis
Tested Gear 50 60 70 80 90
100
110
120
130
Ord 40
dBV
Mix
Antrieb GM
2 *GM
Ghost
Orders
40 Nm
10-40 Nm
Torsional
Accelerometer
Test Sequence is steady speed or ramp n
3000 t M
15-20 s t

3. Revolution Synchronous Transmission Analysis
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.
Input Shaft
Interm. Shaft
Output Shaft
Synchronous
order analysis:
The signals are
acquired synchronous
to the inner shafts.
Acoustical
Stroboscope
Input Shaft
Interm. Shaft
Output Shaft

4. Torsional Accelerometer
Optical Receiver
Power Transformer
Into Rotator
LED Sender
Accelerometers
Rotational ensor

5. Torsional Accelerometer
Accelerometers measure the deviation from uniform circular motion
Power Transformer
Into Rotator
Optical Receiver
Optical Sender
Accelerometers
Rotating Sensor

6. Single Flank Gear Tester Linnenbrink
Torsional Accelerometer
Test gear
Master Gear

7. Results from Crank/Cam Gear pairs
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.
Crank
Gear
Cam
Gear
Good Gear Set
Eccentricity on
Cam Gear
Nick on
Cam Gear

8. Comparing DIN 3960 composite inspection
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
fk’ tooth to tooth deviation
short wave component
fk’
fk’
Fi’ tangential composite deviation
Long wave component
Fi’
Fi’
Eccentricity on
Cam Gear
Good Gear Set

9. Synchronous Averaging III
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 50 60 70 80 90
100
110
120
130
Ord 40
dBV
Mix
Antrieb GM
2 *GM
Ghost
Orders
Ecc..

10. Results from Single Flank Gear Tester
Drive
Coast H3 H1 H2
Crank
Cam
Various filed units shown as stray bands. The gear mesh energies are clearly seen.

11. 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.

12. Spectral Statistics
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.