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Title: Comparison of planetary bearing load-sharing characteristics in wind turbine gearboxes

Abstract

Abstract. In this paper, the planetary load-sharing behavior and fatigue life of different wind turbine gearboxes when subjected to rotor moments are examined. Two planetary bearing designs are compared – one design using cylindrical roller bearings with clearance and the other design using preloaded tapered roller bearings to support both the carrier and planet gears. Each design was developed and integrated into a 750kW dynamometer tests, the loads on each planet bearing row were measured and compared to finite-element models. Bearing loads were not equally shared between the set of cylindrical roller bearings supporting the planets even in pure torque conditions, with one bearing supporting up to 46% more load than expected. A significant improvement in planetary bearing load sharing was demonstrated in the gearbox with preloaded tapered roller bearings with maximum loads 20% lower than the gearbox with cylindrical roller bearings. Bearing life was calculated with a representative duty cycle measured from field tests. The predicted fatigue life of the eight combined planet and carrier bearings for the gearbox with preloaded tapered roller bearings is 3.5 times greater than for the gearbox with cylindrical roller bearings. The influence of other factors, such as carrier and planet bearing clearance, gravity,more » and tangential pin position error, is also investigated. The combined effect of gravity and carrier bearing clearance was primarily responsible for unequal load sharing. Reducing carrier bearing clearance significantly improved load sharing, while reducing planet clearance did not. Normal tangential pin position error did not impact load sharing due to the floating sun design of this three-planet gearbox.« less

Authors:
ORCiD logo [1];  [1];  [2];  [3]
  1. National Renewable Energy Lab. (NREL), Golden, CO (United States)
  2. Romax Technology, Boulder, CO (United States)
  3. The Timken Co., North Canton, OH (United States)
Publication Date:
Research Org.:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org.:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Wind Energy Technologies Office (EE-4WE)
OSTI Identifier:
1488673
Alternate Identifier(s):
OSTI ID: 1489182
Report Number(s):
NREL/JA-5000-71200
Journal ID: ISSN 2366-7451
Grant/Contract Number:  
AC36-08GO28308
Resource Type:
Journal Article: Published Article
Journal Name:
Wind Energy Science (Online)
Additional Journal Information:
Journal Volume: 3; Journal Issue: 2; Journal ID: ISSN 2366-7451
Publisher:
European Wind Energy Association - Copernicus
Country of Publication:
United States
Language:
English
Subject:
17 WIND ENERGY; gearboxes; wind turbines; planetary load-sharing

Citation Formats

Keller, Jonathan, Guo, Yi, Zhang, Zhiwei, and Lucas, Doug. Comparison of planetary bearing load-sharing characteristics in wind turbine gearboxes. United States: N. p., 2018. Web. doi:10.5194/wes-3-947-2018.
Keller, Jonathan, Guo, Yi, Zhang, Zhiwei, & Lucas, Doug. Comparison of planetary bearing load-sharing characteristics in wind turbine gearboxes. United States. doi:10.5194/wes-3-947-2018.
Keller, Jonathan, Guo, Yi, Zhang, Zhiwei, and Lucas, Doug. Fri . "Comparison of planetary bearing load-sharing characteristics in wind turbine gearboxes". United States. doi:10.5194/wes-3-947-2018.
@article{osti_1488673,
title = {Comparison of planetary bearing load-sharing characteristics in wind turbine gearboxes},
author = {Keller, Jonathan and Guo, Yi and Zhang, Zhiwei and Lucas, Doug},
abstractNote = {Abstract. In this paper, the planetary load-sharing behavior and fatigue life of different wind turbine gearboxes when subjected to rotor moments are examined. Two planetary bearing designs are compared – one design using cylindrical roller bearings with clearance and the other design using preloaded tapered roller bearings to support both the carrier and planet gears. Each design was developed and integrated into a 750kW dynamometer tests, the loads on each planet bearing row were measured and compared to finite-element models. Bearing loads were not equally shared between the set of cylindrical roller bearings supporting the planets even in pure torque conditions, with one bearing supporting up to 46% more load than expected. A significant improvement in planetary bearing load sharing was demonstrated in the gearbox with preloaded tapered roller bearings with maximum loads 20% lower than the gearbox with cylindrical roller bearings. Bearing life was calculated with a representative duty cycle measured from field tests. The predicted fatigue life of the eight combined planet and carrier bearings for the gearbox with preloaded tapered roller bearings is 3.5 times greater than for the gearbox with cylindrical roller bearings. The influence of other factors, such as carrier and planet bearing clearance, gravity, and tangential pin position error, is also investigated. The combined effect of gravity and carrier bearing clearance was primarily responsible for unequal load sharing. Reducing carrier bearing clearance significantly improved load sharing, while reducing planet clearance did not. Normal tangential pin position error did not impact load sharing due to the floating sun design of this three-planet gearbox.},
doi = {10.5194/wes-3-947-2018},
journal = {Wind Energy Science (Online)},
issn = {2366-7451},
number = 2,
volume = 3,
place = {United States},
year = {2018},
month = {12}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.5194/wes-3-947-2018

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