Ringwandern in Planetenradlagern von Windenergieanlagen

• Ring creep in wind turbine planetary bearings

Schlüter, Felix Matthew; Jacobs, Georg (Thesis advisor); Hasse, Alexander (Thesis advisor)

Aachen : RWTH Aachen University (2022)
Dissertation / PhD Thesis

Dissertation, Rheinisch-Westfälische Technische Hochschule Aachen, 2022

Abstract

Wind turbines (WTs) constitute a significant pillar of the future energy supply from renewable sources. Increasing the reliability of WTs - and their gearboxes - is therefore one of the present key challenges in order to further reduce the costs of the energy supply system of the future. The vast majority of today's WTs in the field utilizes roller bearings as planetary bearings - this being the highest loaded bearing position in the gearbox. To ensure a tight fit, the bearing outer rings are press-fitted into the planetary gear during assembly. Despite correct design and implementation according to current guidelines, an unwanted movement of these bearing outer rings relative to the planetary gear occurs. This movement is referred to as ring creep and causes abrasive wear in the bearing seat, leading to further consequential damage to the gearbox. Through profound research in the past years, extensive knowledge was gained on the basic mechanism of ring creep and numerous influencing parameters. In this research, the load distributions over the width of the tooth engagements of the planetary gear with sun and ring gear were identified as relevant, but have not been investigated yet. Therefore, this represents a white spot in the state of knowledge. Furthermore, a four-row bearing arrangement in a size representative for gearboxes in WTs has not been investigated so far. In this dissertation, it is first described how ring creep of two planetary bearing outer rings of a WT gearbox can be investigated without abstraction losses on a component test bench, taking all relevant kinematic conditions into account. The designed test bench allows the application of off-centered loads in both gear engagements. The interaction between gear and bearing loads is discussed theoretically and verified by measurement. The load-dependent ring creep movements of the rotor-sided and generator-sided bearing rings clearly and reproducibly differ from one another. The influence of off-centered gear load distributions can also be clearly demonstrated and is in line with theoretical considerations presented in this work. It was shown that a significant reduction in ring creep is possible by combining the investigated load cases in a systematic manner.

Institutions

• Chair and Institute for Machine Elements and Systems Engineering [411710]