Effect of Internal Clearance on Load Distribution and Life of Radially Loaded Ball and Roller Bearings

Oswald, Fred B.; Zaretsky, E. V.; Poplawski, J. V.

doi:10.1080/10402004.2011.639050

Cited by 99 publications

(54 citation statements)

References 4 publications

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“…The output shaft of the gearbox is connected to the generator with a flexible coupling. The rated rotor speed is 22.1 rpm, and with a ratio of 81.491, the gearbox increases the output speed to 1800 rpm (Oyague, 2011;Link et al, 2011). The planetary stage features a floating sun to help equalize the load distribution among the three equally spaced planets, accomplished with a hollow low-speed shaft that has an internal spline connection to the sun pinion .…”

Section: Gearbox Design and Test Programmentioning

confidence: 99%

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

Keller

Guo

Zhang³

et al. 2018

Wind Energ. Sci.

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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.Published by Copernicus Publications on behalf of the European Academy of Wind Energy e.V.

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Section: Gearbox Design and Test Programmentioning

confidence: 99%

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

Keller

Guo

Zhang³

et al. 2018

Wind Energ. Sci.

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show abstract

“…An increasing clearance leads to a decreasing stiffness. Furthermore, Oswald et al (2012) [11]; Nguyen-Schäfer (2016) [12] pointed out that the internal clearance strongly affects load distribution as well as wear and therefore, the fatigue life of radially loaded deep-groove ball and cylindrical roller bearings. In order to enhance the durability of rolling element bearings, the internal clearance is adapted to the load case as described above and cannot be measured or re-adapted without dismounting the bearing from the housing.…”

Section: Introductionmentioning

confidence: 99%

Vibration analysis based on the spectrum kurtosis for adjustment and monitoring of ball bearing radial clearance

2018

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Vibration signal analysis is a common tool to detect bearing condition. Effective methods of vibration signal analysis should extract useful information for bearing condition monitoring and fault diagnosis. Spectral kurtosis (SK) represents one valuable tool for these purposes. The aim of this paper is to study the relationship between bearing clearance and bearing vibration frequencies based on SK method. It also reveals the effect of the bearing clearance on the bearing vibration characteristic frequencies This enables adjustment of bearing clearance in situ, which could significantly affect the performance of the bearings. Furthermore, the application of the proposed method using SK on the measured data offers useful information for predicting bearing clearance change. Bearing vibration data recorded at various clearance settings on a floating and a fixed bearing mounted on a shaft are the basis of this study

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“…Two different gearbox designs were purposefully developed, manufactured, and tested. As shown in In many applications, a small preload, creating a small negative operating clearance, can optimize roller loads and maximize bearing life (Oswald et al, 2012). These preloaded bearings, along with interference-fitted planet pins, improve planet alignments and load-sharing characteristics.…”

Section: Gearbox Design and Test Program 30mentioning

confidence: 99%

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

Keller¹,

Guo²,

Zhang³

et al. 2018

Preprint

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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 10 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 15 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. 20

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Effect of Internal Clearance on Load Distribution and Life of Radially Loaded Ball and Roller Bearings

Cited by 99 publications

References 4 publications

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

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

Vibration analysis based on the spectrum kurtosis for adjustment and monitoring of ball bearing radial clearance

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

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