A&T 2016, Torino Lingotto Fiere Sessione specialistica del 21 aprile 2016, ore 10:00 - 12:15 Relatore: Xanti Amandoz (Tekniker)

1. “Effects of manufacturing errors in
the behaviour of a power gearbox”
.
(OPTIMIZE Project)
X. Almandoz1, J. Presa2, B. Fernández-Díaz1 A. Igartua1, E. San José2, J. C. Rodríguez1, J. Arana1, I. Martínez-
Alcocer1, J. Amores2
1IK4-TEKNIKER, Eibar, Gipuzkoa, Basque Country, Spain
2DMP, Mendaro, Gipuzkoa, Basque Country, Spain
TECHNICAL SESSION - Gear measures: problems and prospects

2. 2
CONTENTS
• OPTIMIZE Project introduction
• Objective of the Project
• Methodology
• Conclusions
Presented by: Ing. Xanti Almandoz xanti.almandoz@tekniker.es

3. OPTIMIZE Project introduction
• Aeronautic market evolution from turbofan
engines technology to geared based
engines to reduce fuel consumption.
• Critical systems, the Power transmission
Gear Boxes (PGB), need to be optimized.
• Funded by JTI Clean Sky (EU 7th Framework
Programme)
• http://www.optimizecleanskyproject.com/

4. 4
Research Center
Eibar (Spain)
www.tekniker.es
Gear manufacturer
Mendaro (Spain)
www.dmp.aero
Transmission manufacturer
Torino (Italy)
www.avioaero.com
OPTIMIZE PROJECT
CONSORTIUM
Presented by: Ing. Xanti Almandoz xanti.almandoz@tekniker.es

5. Objective of the project
Evaluate the effect on gear efficiency of the variation of different
macro and micro geometrical parameters:
 Pressure angle (α)
 Total cumulative pitch deviation (Fp)
 Total profile deviation (Fα)
 Total helix deviation (Fβ).

6. Methodology
Definition of gears to be tested
Design of Experiments (DoE)
 Selection of outputs to be measured
Definition of testing procedure
Regression analysis of the results
Test campaign
Gears Manufacturing Adequacy of test rig

7. Definition of gears to be tested
Gears defined
Requirements
Manufacturing constraints
Test rig constraints
Pinion Wheel
Number
of teeth
28 42
Gear ratio 1:1.5
Normal
module
2.6143 mm
Normal
pressure
angle
20 or 22.5 deg
Face
Width
15 mm
Centre
distance
91.5 mm
Material
AISI9310 per
AMS6265

8. Design of Experiments (DoE) α Fα Fβ Fp Test number
20.0 deg
MIN
MIN
MIN #1
MAX #2
MAX
MIN #3
MAX #4
MAX
MIN
MIN #5
MAX #6
MAX
MIN #7
MAX #8
22.5 deg
MAX
MIN
MIN #9
MAX #10
MAX
MIN #11
MAX #12
MAX
MIN
MIN #13
MAX #14
MAX
MIN #15
MAX #16
 4 input factors are considered.
 2 levels for each factor are fixed.
• ∆Fα = 11 µm
• ∆Fβ = 10 µm
• ∆Fp = 37 µm
 Number of tests = 24 = 16

9. Selection of outputs to be measured
Vibration level in X, Y, Z directions (m/s2).
Gear box oil temperature (ºC).
Torque in driver shaft (Nm).
Rotation speed (rpm).
Current consumption in motor (A).
Noise level (dB).
Transmission error (mrad).
Scuffing damaged area on teeth flanges (mm2).
Pitting and micropitting damaged area on teeth flanges (mm2).
Bending stress (MPa).

10. Definition of testing procedure
Running in before tests
 Transmission error and Power Losses test
 Scuffing test
 Pitting test
 Load Capacity test

11. Transmission error and Power Losses test
Pinion
preload
torque
Initial
temperature
Wheel
speed
Time
Number of
wheel
cycles
205 Nm 60 ºC
100 rpm 10 minutes 1000
1,000 rpm 10 minutes 10,000
2,000 rpm 10 minutes 20,000
Signals will be recorded automatically.
Test conditions

12. Scuffing test
Pinion
preload
torque
Initial
temperature
Wheel
speed
Time
Number of
wheel
cycles
239 Nm
90 ºC 1,200 rpm
15 minutes 19,500
320 Nm 15 minutes 19,500
372 Nm 15 minutes 19,500
450 Nm 15 minutes 19,500
Visual inspection after each load stage.
Test conditions
Scuffing

13. Pitting test
Pinion
preload
torque
Initial
temperature
Wheel
speed
Inspection
time
Number of
wheel
cycles
450 Nm 60 ºC 1,200 rpm
72 hours 5,184,000
96 hours 6,912,000
120 hours 8,640,000
144 hours 10,368,000
Visual inspection at each inspection time.
Test conditions
Pitting

14. Load Capacity test
Pinion
preload
torque
Temperature
Wheel
speed
Number of
wheel
cycles
205 Nm Ambient Manually 1 tooth
Test conditions
Stress will be measured with
strain gauges.

15. Parameters defined in DoE
Gears manufacturing
 4 types of gears Gear name Process name Teeth number Pressure Angle [º]
90004_28Z_20P DR02345A 28 20
90004_42Z_20P DR02346A 42 20
90004_28Z_22,5P DR02349A 28 22,5
90004_42Z_22,5P DR023506A 42 22,5
 Process
• Material reception
and inspection
• Turning
• Previous grinding
• Wire cutting
• Metrology
• Final grinding
• Measurement

16. Adequacy of test rig
Test wheel Test pinion
FZG gear test rig

17. Adequacy of test rig
Customization with sensors
Pinion shaft encoder
Triaxial accelerometer
Wheel shaft encoder
Motor
Torque sensor

18. Test campaign
Test currently running.
End of project planned for July 2016.
Some expected results according to previous simulations.

19. Conclusions
ACKNOWLEDGEMENTS
This project has received funding from the European Union’s
Seventh Framework Programme for research, technological
development and demonstration (JTI Clean Sky) under grant
agreement nº 641542.
• A testing methodology has been proposed to analyse the effect of
different geometrical parameters on gear efficiency.
• Gears have been manufactured according to DoE requirements and
a test rig has been modify to properly quantify each physical effect to
be analysed.
• Experimental results will be compared with preliminary numerical
analysis.