The 11th International VDI Conference on Gears 2025 will be held in Garching, Munich at the Gear Research Centre (FZG) of the Technical University of Munich from September 10th to 12th, 2025. Presenting a paper gives you the opportunity to take part in this leading international forum and to learn about the latest developments and research results in the powertrain industry and academia. Abstracts are due November 22, 2024!
Since our founding in 1984, Gear Technology’s goal has been to improve your knowledge, bringing you the best possible technical information about gear design, manufacturing, inspection, heat treating and much more. We keep you informed about the business of gear manufacturing, including the trends and technologies that will shape your companies in the coming years.
To increase cost efficiency in wind turbines, the wind industry
has seen a significant rise in power density and an increase in the overall size of geared components. Current designs for multimegawatt turbines demand levelized cost of energy (LCOE) reduction, and the gearbox is a key part of this process. Since fatigue failures nearly always occur at or near the surface, where the stresses are greatest, the surface condition strongly affects the gear life. Consequently, an improved surface condition effectively avoids major redesign or increased material cost due to an increase in part size. Additional finishing methods such as shot peening (SP) and superfinishing (SF) significantly increase the gear load capacity, but these effects have not yet been adequately considered in the current ISO 6336 standard or in any other gear standards. The combination of SP followed by SF will be described here as an “improved gear surface” (IGS).
Standardized methods, like AGMA 2001-D04 or ISO 6336 for the calculation of the load carrying capacities of gears are intentionally conservative to ensure broad applicability in industrial practice. However, new applications and higher requirements often demand more detailed design calculations nowadays; for example: long operating lives in wind power gearboxes or fewer gear stages and higher speeds in e-mobility applications result in higher load cycles per tooth in a gearbox.
A calculation-based study of different variants with regard to contact ratio and tooth root geometry to compare the results from the 2019 version of ISO 6336 to the previous version, released in 2006.
The common calculation methods according to DIN 3990 and
ISO 6336 are based on a comparison of occurring stress and
allowable stress. The influence of gear size on the load-carrying
capacity is considered with the size factors YX (tooth root bending)
and ZX (pitting), but there are further influences, which
should be considered.
In the following, major influences of gear size on the load factors
as well as on the permissible tooth root bending and contact
stress will be discussed.
In order to properly select a grease for a particular application, a sound knowledge of the influence of different grease components and operating conditions on the lubrication supply mechanism and on different failure modes is of great benefit.