Testing of Convoloid® Gear Forms for Wind Turbine Applications · Testing of Convoloid® Gear Forms for Wind Turbine Applications © Dontyne Systems Limited 2012 Test Results - Durability

© Dontyne Systems Limited 2008Dontyne Systems Limited is a company registered in England and Wales with company number 05973058Registered office: 1 Simonside, Prudhoe, Northumberland, ENGLAND, NE42 6LJVAT Registration Number: 902 9027 45

© Dontyne Systems Limited 2012

23rd May 2012

23rd May 2012

Testing of Convoloid® Gear Forms

for Wind Turbine Applications

© Dontyne Systems Limited 2012Testing of Convoloid® Gear Forms for Wind Turbine Applications

Introduction Background & Development

Test Program for Convoloid® Gears

Economic & Environmental Benefits

Virtual Testing – Software Development Program

Summary


Test Program Project ManagerBarney Berlinger

Managing Partner, Genesis Partners LP

Project ManagerBarney Berlinger

Managing Partner, Genesis Partners LP

Genesis Partners LPV.P., Engineering – Allen Williston

Chief Technical Officer – John Colbourne

Genesis Partners LPV.P., Engineering – Allen Williston

Chief Technical Officer – John Colbourne

Technical ConsultantsDon McVittie (Gear Engineers)

Andy Milburn (Milburn Engineering)

Technical ConsultantsDon McVittie (Gear Engineers)

Andy Milburn (Milburn Engineering)

Test ConsultantDick Meredith (DC Energy)

Test ConsultantDick Meredith (DC Energy)

Project management structure


Test Program - Durability Establish test conditionsLubricant -- 80w90 Gear Oil with API GL5 Additive PackageLubricant bulk temperature -- 160°FEHD Film Thickness -- approximately 8 micro-inch (depending on load)Lubricant change interval -- 2000 hours (approximately)Lubricant filter -- 10-micron ceramic filamentSpecimen -- 3 inch pitch diameter spur gear provided by Genesis LLPMate -- 5 inch pitch diameter spur gear provided by Genesis LLPSpecimen Operating Speed -- 900 RPM (nominal)Run-in Procedure -- Load to minimal load and run one hour – in cold oil with no heater. Load to 30% test

load and run two hours – with no heater. Load to Full load and inspect after one hour – with no heater.Test Loads -- First test to be conducted at 3500 pound inches (on specimen). Loads for subsequent tests

will be determined based on the outcome of the first testRun-Out -- Tests will be suspended after 30 million cycles with no failure


Test Program - Durability Failure criteria

Surface origin pits about 3/16 inch wideor tooth breakageor 0.001” (approximately) profile changeor progressive scoringor severe vibration.


Test Program - Durability

No load marking on Involute (left) after 4 hours and Convoloid® (right) after 1 hour.Note contact at tooth tip and root on Convoloid®, no contact at pitch line.


Test Results - Durability Torque Cycles Diagram

1.E+04 1.E+05 1.E+06 1.E+07 1.E+08

Life - Cycles

Based on AGMA 925-A03 Effect of Lubrication on Gear Surface Distress - Regime II Lubrication and AGMA Grade 2 300 HB through hardened material

Results of Tests with Involute Specimens - Surface Durability Failures

Results of Tests with Convoloid Specimens - Bending Failures

Surface Durability Allowable for Involute Specimens

Surface Durability Allowable for Convoloid Specimens

Bending Allowable for Involute Specimens

Bending Allowable for Convoloid Specimens

2 Tests

Approximate 50% Bending Failures for Involute Specimens,after AGMA

Approximate 50% Surface Failures for Involute Specimens, After AGMA


Test Results - Durability Weibull Diagram

1.E+05 1.E+06 1.E+07 1.E+08

Life (Cycles)

Failu

re R

ate

- Per

cent

90

0.1

0.5

1

5

20

40

30

10

50

99 99.5

95

80

70

60

Test Results @ 3500 pound-inchesInvolute Convoloid

50% Confidence 50% ConfidenceG10 680,000 cycles G10 4,200,000 cyclesG50 1,230,000 cycles G50 5,600,000 cyclesG90 1,800,000 cycles G90 6,800,000 cycles

Weibull Slope 3 Weibull Slope 7

95% Confidence 95% ConfidenceG10 240,000 cycles G10 2,500,000 cycles

5% Confidence

50% Confidence

95% Confidence

ConvoloidTooth Breakage

Failure

InvoluteSurface Durability

Failure

50% Confidence

5% Confidence

95% Confidence

Test results used to establish curves at 5%, 50%, and 95% confidence


Test Program

Micon 108 back-to-back test stand arrangement


Test Program

Micon 108 back-to-back test stand


Test Program

Preliminary Low Speed gearing comparison for Micon-108 test


Test Program

Preliminary High Speed gearing comparison for Micon-108 test


Test Program

Low Speed Test Design - A full design spec of the involute gearing for the involute gearing under the 240% load is available


Test Program

High Speed Test Design - A full design spec of the involute gearing for the involute gearing under the 240% load is available


Test Program

Test Gears Produced To AGMA 2000 - 12

Early profile inspection trace of Convoloid® 13 tooth Pinion


Test Program

Convoloid® High Speed gear mesh no-load contact patch after lead modification. Gearing has been assembled into the test housing

Convoloid® (with lead crowning) were

checked for alignment on assembly before 200% load test for

200 hours


Test Program

Load/Power Summary for Micon 108 test including extended testing for testing carried out at National Renewable Energy Laboratory

(Testing halted due to damaged bearing and debris in the box)


Test Program

Sound spectrum at a distance of 10 feet after approximately 300 hours of operation


Test Results

Non-Gear inefficiencies found to be slightly higher in Convoloid® tests. Mesh efficiency of Involute and Convoloid® gears determined as 98.9% after subtraction

from total

Involute

Convoloid®


Economic Benefit

A 5MW Wind Turbine Gearbox GPSPL014The Convoloid arrangement is 29% lighter than the equivalent

involute box


Economic Benefit

Representative 750 kW gearbox


Economic Benefit

Redesigned 750 kW gearbox Low Speed (planetary) using Convoloid® gears


Economic Benefit

Comparison between an existing 750kW planetary stage and the Convoloid® design


Economic BenefitQualifiers: US data onlyConservative market penetration rates for Convoloid® Technology into the Wind Turbine Gear Box market.Cost saving rate for Convoloid® gear systems versus their classical involute counterparts at €30,201 per MWTotal Steel Savings using Table 3-1 and 3-2 of “20% Wind” publication, page 63. “Steel Savings” relates only to the high grade Class 2 carburizing steel used for the gears.Not included; housing weights, bearing weights and accessory shaft weights, extra steps add to the pollutant by products of the process which are undetermined at this timeProjected U.S. Production Growth figures are very conservative and are extracted from Page 66 of the “20% Wind by 2030” publication. (see Wind Power Monthly –March 2009 – page 41).CO2 reductions are based on installed capacity increases in Column 1 at the rate of 7.96 metric tons per MW and then applied only to the Convoloid® geared machines. Level electrical demand was assumed since 2000 which is not the case as demand has increased since then. Demand is expected to grow aggressively in the next decade. –Reference- “Carbon Dioxide Emissions from the Generation of Electric Power in the United States”. July 2000, page 2, U.S. DOE and EPA.


Economic Benefit

Significant benefits in costs, resources, and emissions (Bold indicates interpolated values)


Economic Benefit

Significant savings to the industry based on conservative 21% improvement in capacity


GATES – Gear Analysis for Transmission Error and Stress

It is an FE based analysis package that calculates;

– Transmission Error (T.E.)– Load sharing between teeth– Surface Contact Stress and Root Bending Stress– Efficiency

Virtual Testing


Background1990- 1992 The Design Unit (Newcastle Upon Tyne U.K.) identify the need

for a sophisticated loaded tooth contact analysis for gears

1992- 1997 A large number of different gears tested at many torques and alignments. Some of the results of which have been published

1997- 2006 Program is implemented using FEA by project founders and collaborators

2006- 2007 Dontyne Systems take over the development and marketing of GATES calculation as part of Load Analysis Model

2007- 2009 Development programs defined and implemented for the expansion of the GATES analysis and scope


ApplicationInitial Development in Marine propulsion systems

– GATES has been used to design gears for British Royal Navy


Contact Model

Link To ISO6336 Design and Rating


Contact Model

Flexible Profile and Lead Definition of 2D

and 3D Surface Topography


Contact Model

Links To Metrology Equipment To Define

Surface From Measured Data

3D Surface Measurement


Analysis OptionsGraphic Presentation:

– 2D chart / 3D chart / Gear surface


Analysis OptionsMultiple Load Levels:

Detailed Tooth-To-Tooth(Plot can be used to derive FFT

Spectrum)

Harris Map Plot(Illustrates Change in Amplitude through load to identify optimum)


Analysis OptionsPower Loss On Tooth:


ExamplesCase #1 - Increase efficiency with surface modifications


Spur gear cut with different pressure angle hob (short lead hob) results in 30% change in stress

20 degree 11 degree

ExamplesCase #2 – Effect of manufacturing on root strength


Validation 1Gear Centres 91.5 mm

Gear Ratio 1.5:1

Wheel Ref Diameter 108.08

Pinion Ref Diameter 72.05

Face Width ~ 25 mm

Pinion Torque 100 – 373 Nm

Experimental data courtesy of:


Validation 1Pinion 100 Nm Wheel 100 Nm








Validation 2The following data is from an experimental study to validate the application of the GATES Transmission error model:

– The aim was to reduce noise levels that arise from the transmission error (T.E.) at the gear mesh

– The T.E. Causes forces that propagate through the system and radiate noise

– A comparison is provided between single, double helical gears and optimised gears using the GATES program



Validation 2Gear Centres 400mm

Gear Ratio 3:1

Wheel Ref Diameter 600

Pinion Ref Diameter 200

Face Width ~ 200mm

Max Pinion Speed 6000rpm

Max Pinion Torque 15000rpm

Max Power 8 MW



Validation 2Experimental data courtesy of:


Validation 2

33Specified AccuracyISO 1328-1/95 Grade

400400Centre Distance, a573.15183.15Root Diameter, df

612222Tip Diameter, da599.839199.946Ref. Diameter, d

200200Face Width, b28.728.7Ref. Helix Angle, βn

17.5°17.5°Ref Pressure Angle, αn

6.056.05Normal Module, mn87 29No of teeth, z

WheelPinion



Validation 2

None15μm CrowningNone20μm CrowningLead

Tip Relief – 10μmx5mm extentRoot Relief - none

Tip Relief – 10μmx5mm extentRoot Relief - none

Tip Relief – 10μmx10.5mm extentRoot Relief - none

Tip Relief – 10μmx10.5mm extentRoot Relief - none

Profile

WheelPinionWheelPinion

Flank BFlank A



Validation 2

Pinion Speed (rpm)

Pinion BearingLoad[N]rms

Flank A

Optimised

Single Helical

DoubleHelical



Validation 2Pinion BearingLoad[N]rms

Pinion Speed (rpm)

Flank B

Single Helical

Double HelicalOptimised



Summary Initial testing shows benefits of Convoloid® gearing over

involute gears Convoloid® gearing potentially has significant economic and

environmental benefit Experimentally validated FE model is a practical

development tool- Graphical view of analysis- Integration to other Dontyne software design tools- Integration to metrology equipment- Proven results for noise and vibration reduction

Continued development and experimental validation


SummaryPublished literature- “Ultra-Low Noise Gearbox” Hofmann D. & Haigh J, Transactions of INEC 2000, Atkins, Hamburg, 14-16 March 2000

- “High Speed Gears for Extreme Applications in Industrial and Marine Fields” Weiss T. & Hoppe F., Gear Technology, Sep-Oct 2007 p 68-74

- “Practical Production of Low Noise Gears”, Penning G., BGA Congress 2008, 20 November 2008

- “Optimisation of Gear Performance Through Surface Engineering”, Aylott C., BGA Congress 2008, 20 November 2008

- “Optimizing Gear Geometry for Minimum Transmission Error, Mesh Friction Losses and Scuffing Risk Through Computer Aided Engineering”, Fraser R., Shaw B, Palmer D. & Fish M. AGMA FTM09, 13-15 September 2009

- “Systematic Optimisation of Gearboxes for Hybrid and Electric Vehicles in Terms of Efficiency, NVH, and Durability”, Grunwald, A., 20. Aachen Colloqium Automobile and Engine Technology 2011


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+44 191 206 4636Asia

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www.dontyne.com

Documents

Testing of Convoloid® Gear Forms for Wind Turbine Applications · Testing of Convoloid® Gear Forms for Wind Turbine Applications © Dontyne Systems Limited 2012 Test Results - Durability