DIN 3991-1:2024-06

This document specifies the methods for calculating the load capacity of bevel and hypoid gears, the formula symbols and abbreviations used for the calculation, and the general load influence factors. The equations of the DIN 3991 series of standards provide a uniformly accepted method for calculating the flank and root load capacity of straight and helical bevel gears, spiral bevel gears, Zerol and hypoid gears, and are equally applicable to gears with constant or conical tooth depth. The calculation system of the DIN 3991 series of standards is based on an equivalent cylindrical gear and is limited to bevel gears whose equivalent cylindrical gear has a contact ratio of ε_va < 2. The standard differs from DIN 3991-1:1988 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) The tolerances in this document refer to the revised edition of the tolerance standard DIN 3965; d) the methods D and E have basically been eliminated; e) the graphical methods for determining calculation factors, as well as Table 4.1, influencing factors C_v1 to C_v7, have been removed; f) Clause 7 for determining the skew factor (scuffing) K_By has been removed; g) revision of normative Annex A for calculating the equivalent cylindrical gearing; h) inclusion of values for the application factor K_A in a new informative Annex B; i) inclusion of contact patterns in a new informative Annex C. 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.