Gears present several failure mechanism that can happen at the same time according to the rotational speed and the load applied.These mechanism are: wear, scuffing, pitting, micro-pitting, tooth flank fracture and tooth root fatigue fracture.
These mechanisms are due to several phenomena: friction, contact (Hertzian pressure, sliding/rolling), bending fatigue and lack of lubrication. All this phenomena can happen simultaneously and they lead to the failure of the gearbox.
The standard ISO 6336[1] and AGMA 2001[2] provide informations regarding this failure mechanism and define calculation method to verify if a gear is safe from such phenomena. Even if the standards provide these informations they strongly suggest to perform experimental test because the standards can not cover all the possible combinations of geometry, material, heat treatment, ecc.
There are different test to study the behaviour of the gear. Due to the fact that the failure mechanism can happen simultaneously the tested gears are designed in order to isolate only one failure mechanism.[3][4]
- ↑ "ISO 6336-1:2019 Calculation of load capacity of spur and helical gears Part 1: Basic principles, introduction and general influence factors". ISO.
- ↑ "ANSI/AGMA 2001 - Fundamental Rating Factors and Calculation Methods for Involute Spur and Helical Gear Teeth".
- ↑ Mechanical Testing and Evaluation. ASM International. 2000-01-01. doi:10.31399/asm.hb.v08.9781627081764. ISBN 978-1-62708-176-4.
- ↑ Halgren, John A.; Wulpi, D. J. (1957). "Laboratory Fatigue Testing of Gears". SAE Transactions. 65: 452–470. ISSN 0096-736X.