“Effects of manufacturing errors in the behaviour of a power gearbox”

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(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

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CONTENTS • OPTIMIZE Project introduction

• Objective of the Project

• Methodology

• Conclusions

Presented by: Ing. Xanti Almandoz xanti.almandoz@tekniker.es

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/

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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

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).

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

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

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

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).

Definition of testing procedure

Running in before tests

Transmission error and Power Losses test Scuffing test Pitting test Load Capacity test

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

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

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

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.

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

Adequacy of test rig

Test wheel Test pinion

FZG gear test rig

Adequacy of test rig

Customization with sensors

Pinion shaft encoder

Triaxial accelerometer

Wheel shaft encoder

Motor

Torque sensor

Test campaign

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

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.