ISO 10300-2:2023

INTERNATIONAL ISO
STANDARD 10300-2
Third edition
2023-08
Calculation of load capacity of bevel
gears —
Part 2:
Calculation of surface durability
(macropitting)
Calcul de la capacité de charge des engrenages coniques —
Partie 2: Calcul de la résistance à la pression superficielle (macro-
écaillage)
Reference number
© ISO 2023
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ii
Contents Page
Foreword .iv
Introduction . vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols, general subscripts and abbreviated terms . 2
5 Macropitting damage — General aspects . 6
5.1 Acceptable versus unacceptable macropitting . 6
5.2 Assessment requirements . 6
5.3 General rating procedure . 7
6 Gear flank rating formulae — Method B1 . 7
6.1 Contact stress formula . 7
6.2 Permissible contact stress . 8
6.3 Calculated safety factor for contact stress . 8
6.4 Contact stress factors . 9
6.4.1 Mid-zone factor, Z . 9
M-B
6.4.2 Load sharing factor, Z . 10
LS
6.5 Permissible contact stress factors . 11
6.5.1 Bevel gear factor, Z . 11
KP
6.5.2 Size factor, Z .12
X
6.5.3 Hypoid factor, Z .12
Hyp
7 Gear flank rating formulae — Method B2 .15
7.1 Contact stress formula .15
7.2 Permissible contact stress . 16
7.3 Calculated safety factor for contact stress . 16
7.4 Contact stress factors . 16
7.4.1 General . 16
7.4.2 Macropitting resistance geometry factor, Z . 17
I
7.4.3 Facewidth factor, Z .20
FW
7.4.4 Contact stress adjustment factor, Z . 20
A
8 Factors for contact stress and permissible contact stress common for method B1
and method B2 .21
8.1 Elasticity factor, Z . 21
E
8.2 Lubricant film influence factors, Z , Z , Z . 21
L v R
8.2.1 General . 21
8.2.2 Restrictions . 21
8.2.3 Method B . . 21
8.2.4 Method C (product of Z , Z and Z ) . 23
L v R
8.3 Work hardening factor, Z .23
W
8.3.1 General .23
8.3.2 Work hardening factor, Z : Method A . 23
W
8.3.3 Work hardening factor, Z : Method B . 24
W
8.4 Life factor, Z . 26
NT
8.4.1 General . 26
8.4.2 Method A . . . 27
8.4.3 Method B .28
Annex A (informative) Local calculation method for surface durability (macropitting) –
Method B1-localised .29
Bibliography .35
iii
Foreword
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This document was prepared by Technical Committee ISO/TC 60, Gears, Subcommittee SC 2, Gear
capacity calculation.
This third edition cancels and replaces the second edition (ISO 10300-2:2014), which has been
technically revised.
The main changes are as follows:
— Table 1 has been inserted;
— Table 2 has been inserted;
— the term “pitting” has been replaced by “macropitting”;
— bevel gear factor, Z , for the calculation of the nominal value of the contact stress has been removed;
K
instead, a new bevel gear factor, Z , has been introduced for the calculation of the permissible
KP
contact stress;
— Formula (37) for the calculation of the length of action considering adjacent teeth has been modified;
— subclause 8.3 — work hardening factor, Z , has been updated and method A added;
W
— Figure 2 — load distribution in the contact area has been updated as the symbol for exponent e has
been changed to e ;
LS
— Figure 6 — facewidth factor, Z has been removed;
FW
— Figure 7 — lubricant factor, Z , for mineral oils has been removed;
L
— Figure 8 — speed factor, Z has been removed;
V
iv
— Figure 9 — roughness factor, Z has been removed;
R
— Figure 10 — work hardening factor, Z has been removed;
W
— former Annex A has been replaced by new Annex A describing a local calculation method for surface
durability (macropitting) – Method B1-localised.
A list of all parts in the ISO 10300 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
v
Introduction
When ISO 10300:2001 (all parts) became due for its first revision, the opportunity was taken to include
hypoid gears, since previously the series only allowed for calculating the load capacity of bevel gears
without offset axes. The former structure is retained, i.e. three parts of the ISO 10300 series, together
with ISO 6336-5, and it is intended to establish general principles and procedures for rating of bevel
gears. Moreover, ISO 10300 (all parts) is designed to facilitate the application of future knowledge and
developments, as well as the exchange of information gained from experience.
In view of the decision for ISO 10300 (all parts) to
...