DIN 3991-2:2024-06

This document specifies the fundamental equations for determining the pitting resistance of straight and helical bevel gears, Zerol, spiral bevel and hypoid gears, and includes all influences on pitting resistance that can be quantitatively assessed. This document applies to oil-lubricated bevel gears, provided that there is always sufficient lubricant in mesh. The equations in this document are based on equivalent cylindrical gears and are limited to bevel gears whose equivalent cylindrical gears have a contact ratio of ε_va < 2. The equations in this document are not directly applicable to the assessment of other flank damage, such as plastic deformation, scratches and scuffing. The standard differs from DIN 3991-2:1988-09 as follows: a) the scope has been extended to include offset bevel gears (hypoid gears), for which the calculation method has been revised; b) for the use of material characteristics, this document refers to the more recent ISO 6336-5, which does not preclude the possibility of a later edition referring to a revised DIN 3990-5; c) a material pairing factor Z_W has been introduced; d) a life factor Z_NT has been included; e) the graphical methods for determining calculation factors have been removed; f) inclusion of a localized calculation method for the pitting load capacity of bevel gears in an informative Annex A. This document has been prepared by Working Committee NA 060-34-13 AA "Kegelradverzahnungen (SpA ISO/TC 60/SC 2/WG 13)" ("Bevel gears (SpA ISO/TC 60/SC 2/WG 13)") of Section "Gear" at DIN Standards Committee Mechanical Engineering (NAM). Representatives of the manufacturers and users of bevel gears and of the universities contributed to this standard.