FVA 795 – Tooth root load capacity of planet gears

Full title:

Tooth root and ring load carrying capacity of thin rimmed planet gears

Contributor:

• The German Federation of Industrial Research Associations (AiF)
• Forschungsvereinigung Antriebstechnik e.V. (FVA)

• Alternating loads combined with an elastic thin rimmed design resulting in a  more complex state of stress compared to equivalent stiff rim designs

• Influences regarding the rim stress, centrifugal forces und the bearing loads are not considering using the present standards

• It is necessary to determine the stress amplitude over the complete circumference of the planet gear and compare it to the mean stress dependent strength value

• Analytical appraoch to determine the nominal rim stress for calculating the load carrying capacity

• Numerical approach to determine the local tooth root stress as well as the stress concentration factors

• Validation of the theoretical methods using fatigue tests at an idler gearbox as well as measuring the local tooth root stress using multiple strain gauge chains within the tooth root curve of a planet gear in a planetary gearbox

The intended result is a calculation method for the tooth root load carrying capacity of thin rimmed planet or idler gears similar to present standards, which has been experimentally validated by the conducted tests.