Discussion: “The Effect of Misalignment on the Fatigue Life of Tapered Roller Bearings” (Zantopulos, H., 1972, ASME J. Lubr. Technol., 94, pp. 181–186)

1972 ◽  
Vol 94 (2) ◽  
pp. 187-187
Author(s):  
N. M. Wickstrand
Keyword(s):  
Fatigue Life ◽  
Roller Bearings ◽  
Tapered Roller ◽  
Tapered Roller Bearings

scholarly journals Comparison of planetary bearing load-sharing characteristics in wind turbine gearboxes

2018 ◽  
Vol 3 (2) ◽  
pp. 947-960 ◽  
Author(s):  
Jonathan Keller ◽  
Yi Guo ◽  
Zhiwei Zhang ◽  
Doug Lucas
Keyword(s):  
Fatigue Life ◽  
Wind Turbine ◽  
Load Sharing ◽  
Position Error ◽  
Bearing Clearance ◽  
Roller Bearings ◽  
Bearing Load ◽  
Tapered Roller ◽  
Tapered Roller Bearings ◽  
Cylindrical Roller

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 750 kW 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.

The Effect of Misalignment on the Fatigue Life of Tapered Roller Bearings

1972 ◽  
Vol 94 (2) ◽  
pp. 181-186 ◽  
Author(s):  
H. Zantopulos
Keyword(s):  
Experimental Study ◽  
Fatigue Life ◽  
Test Data ◽  
Load Distribution ◽  
Roller Bearings ◽  
Bearing Life ◽  
Life Tests ◽  
Tapered Roller ◽  
Tapered Roller Bearings ◽  
Sufficient Test

A comprehensive analytical and experimental study of the effect of misalignment on load distribution and fatigue life of tapered roller bearings is presented. Included are the effects of truncation of crowned rollers and edge of contact stresses. Bearing life tests, involving approximately 500 bearings, were run at various loads and misalignments to obtain sufficient test data to substantiate the analytical results.

scholarly journals Comparison of Planetary Bearing Load-Sharing Characteristics in Wind Turbine Gearboxes

2018 ◽  
Author(s):  
Jonathan Keller ◽  
Yi Guo ◽  
Zhiwei Zhang ◽  
Doug Lucas
Keyword(s):  
Fatigue Life ◽  
Wind Turbine ◽  
Load Sharing ◽  
Position Error ◽  
Bearing Clearance ◽  
Roller Bearings ◽  
Bearing Load ◽  
Tapered Roller ◽  
Tapered Roller Bearings ◽  
Cylindrical Roller

Abstract. In this paper, the planetary load-sharing behaviour 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 750-kilowatt gearbox. In field-representative dynamometer tests, the loads on each planet bearing row were measured and compared to finite element models. 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.

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