Influence of ring gear flexibility on the fatigue reliability of planetary gear systems in heavy helicopters

•The impact mechanism of ring gear rims on planet system reliability is revealed.•Mapping from ring gear rim thickness to planet system reliability is established.•Balance the contradiction between the accuracy and cost of reliability evaluation.•The range of rim thicknesses with the best reliabilit...

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Bibliographic Details
Published in:Mechanism and machine theory 2024-01, Vol.191, p.105520, Article 105520
Main Authors: Li, Ming, Luo, Yuan, Qu, Ligang, Xie, Liyang, Zhao, Bingfeng
Format: Article
Language:English
Subjects:
Fatigue reliability
Flexible ring gear
Group test
Hybrid finite element
Planetary gear system
Tooth root breakage
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Summary:•The impact mechanism of ring gear rims on planet system reliability is revealed.•Mapping from ring gear rim thickness to planet system reliability is established.•Balance the contradiction between the accuracy and cost of reliability evaluation.•The range of rim thicknesses with the best reliability improvement is determined. Flexibility of ring gear rims significantly affects the mechanical properties of planetary transmissions at both levels of gear tooth meshing and system power sharing, and is one of the important design factors determining the service reliability of large aviation planetary systems. Therefore, to analyze the mechanism by which the flexibility of ring gear rims affects the fatigue reliability of planetary systems, in the framework of the stress-strength interference theory, a reliability assessment model for the planetary system is constructed based on a calculation logic extension for the full probability formula. Starting from balancing evaluation accuracy and evaluation cost, a hybrid finite element method and a gear tooth lifetime transformation test are employed to provide load and strength input variables for the reliability model respectively. Finally, a mapping relationship from ring gear rim flexibility to planetary system fatigue reliability is established. For the specific design scheme of planetary systems, a lower limit of the ring gear rim thickness can be determined according to the requirements of reliability indexes, so that the balance between reliability and lightweight can be achieved to some extent.
ISSN:0094-114X
DOI:10.1016/j.mechmachtheory.2023.105520