NF ISO 6336-2

Le présent document fait partie d'un ensemble de normes sur le calcul de la capacité de charge des roues cylindriques à denture intérieure ou extérieure et à profil en développante de cercle. La présente partie donne les formules de base à utiliser pour déterminer la résistance à la pression de contact. La pression de Hertz, indicateur significatif de la pression de contact, est l'hypothèse utilisée dans ces calculs. Cependant d'autres facteurs d'influence sont pris en compte, quand une évaluation qualitative de ces derniers est possible.

This document specifies the fundamental formulae for use in the determination of the surface load capacity of cylindrical gears with involute external or internal teeth. It includes formulae for all influences on surface durability for which quantitative assessments can be made. It applies primarily to oil‑lubricated transmissions, but can also be used to obtain approximate values for (slow‑running) grease‑lubricated transmissions, as long as sufficient lubricant is present in the mesh at all times. The given formulae are valid for cylindrical gears with tooth profiles in accordance with the basic rack standardized in ISO 53. They can also be used for teeth conjugate to other basic racks where the actual transverse contact ratio is less than εαn = 2,5. The results are in good agreement with other methods (see References [5], [7], [10], [12]). These formulae cannot be directly applied for the assessment of types of gear tooth surface damage such as plastic yielding, scratching, scuffing and so on, other than that described in Clause 4. The load capacity determined by way of the permissible contact stress is called the "surface load capacity" or "surface durability". If this scope does not apply, refer to ISO 6336-1:2019, Clause 4.