A study of grease lubricants under wind turbine pitch bearing conditions

verfasst von

Fabian Schwack, Norbert Bader, Johan Leckner, Claire Demaille, Gerhard Poll

Abstract

Pitch bearings in wind turbines are affected by reciprocating motion due to pitch control. The combination of oscillating operation, high loads, and mixed lubrication often leads to wear. Grease lubricants in wind turbine pitch bearings should be designed to avoid such wear. Due to different available grease lubricants, the anti-wear properties are investigated under downscaled wind turbine pitch bearing conditions. The downscaling is accomplished by load simulation for a pitch bearing and analysis of the pitch movements for a 7.5 MW reference turbine. The operational conditions of the four point contact ball bearing with 5 m outer diameter are scaled to angular contact ball bearings of the size 7208. The investigations are concluded with contact model experiments. Six Industrial grease lubricants for wind turbine pitch bearings are tested that follow very different compositions. The investigations reveal, that none of the tested grease lubricants was able to reduce wear for all tested conditions. After 250000 cycles certain conditions lead to severe wear. Therefore, the pitch controller should avoid such conditions if possible. Nevertheless, grease lubricants with low base oil viscosities and high bleeding rates are best on average for the tested conditions. Furthermore, the results of the bearing experiments are comparable to the model experiments.

Organisationseinheit(en)

Institut für Maschinenkonstruktion und Tribologie

Externe Organisation(en)

Royal Institute of Technology (KTH)
Axel Christiernsson International AB

Typ

Artikel

Journal

Wear

Band

454-455

ISSN

0043-1648

Publikationsdatum

15.08.2020

Publikationsstatus

Veröffentlicht

Peer-reviewed

Ja

ASJC Scopus Sachgebiete

Physik der kondensierten Materie, Werkstoffmechanik, Oberflächen und Grenzflächen, Oberflächen, Beschichtungen und Folien, Werkstoffchemie

Elektronische Version(en)

https://doi.org/10.1016/j.wear.2020.203335 (Zugang: Offen)