ISO/TR 10300-32:2021

TECHNICAL ISO/TR
REPORT 10300-32
First edition
2021-04
Calculation of load capacity of bevel
gears —
Part 32:
ISO rating system for bevel and hypoid
gears — Sample calculation for
scuffing load capacity
Reference number
©
ISO 2021
© ISO 2021
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ii © ISO 2021 – All rights reserved

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols . 1
5 Application . 2
Annex A (informative) Sample 1: Rating of a spiral bevel gear pair without hypoid offset
according to ISO/TS 10300-20 . 3
Annex B (informative) Sample 2: Rating of a hypoid gear set according to ISO/TS 10300-20 .44
Annex C (informative) Sample 3: Rating of a hypoid gear set according to ISO/TS 10300-20 .85
Annex D (informative) Sample 4: Rating of a hypoid gear set according to ISO/TS 10300-20 .126
Bibliography .167
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
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ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
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iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 60, Gears, Subcommittee SC 2, Gear
capacity calculation.
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.
iv © ISO 2021 – All rights reserved

Introduction
The ISO 10300 series consists of International Standards, Technical Specifications (TS) and Technical
Reports (TR) under the general title Calculation of load capacity of bevel gears (see Table 1).
— International Standards contain calculation methods that are based on widely accepted practices
and have been validated.
— TS contain calculation methods that are still subject to further development.
— TR contain data that is informative, such as example calculations.
The procedures specified in ISO 10300 parts 1 to 19 cover fatigue analyses for gear rating. The
procedures described in ISO 10300 parts 20 to 29 are predominantly related to the tribological
behaviour of the lubricated flank surface contact. ISO 10300 parts 30 to 39 include example calculations.
ISO 10300 series allows the addition of new parts under appropriate numbers to reflect knowledge
gained in the future.
Requesting standardized calculations according to ISO 10300 without referring to specific parts
requires the use of only those parts that are currently designated as International Standards (see
Table 1 for listing). When requesting further calculations, the relevant part or parts of ISO 10300 need
to be specified. Use of a Technical Specification as acceptance criteria for a specific design need to be
agreed in advance between manufacturer and purchaser.
Table 1 — Parts of ISO 10300 series (status as of DATE OF PUBLICATION)
International Technical Technical
Calculation of load capacity of bevel gears
Standard Specification Report
a
Part 1: Introduction and general influence factors X
a
Part 2: Calculation of surface durability (pitting) X
a
Part 3: Calculation of tooth root strength X
Part 4 to 19: to be assigned
Part 20: Calculation of scuffing load capacity — Flash
X
temperature method
Part 21 to 29: to be assigned
Part 30: ISO rating system for bevel and hypoid gears —
X
Sample calculations
Part 32: ISO rating system for bevel and hypoid gears —
X
Sample Calculations of scuffing load capacity
a
Under revision.
This document and the other parts of ISO 10300 series provide a coherent system of procedures for
the calculation of the load capacity of bevel and hypoid gears. ISO 10300 series is designed to facilitate
the application of future knowledge and developments, also the exchange of information gained from
experience.
TECHNICAL REPORT ISO/TR 10300-32:2021(E)
Calculation of load capacity of bevel gears —
Part 32:
ISO rating system for bevel and hypoid gears — Sample
calculation for scuffing load capacity
WARNING — The user is cautioned that when the formulae are used for large average mean spiral
angles, (β + β )/2 > 45°, for effective pressure angles, α > 30° and/or for large face widths,
m1 m2 e
b > 13 m , the calculated results of the ISO 10300 series should be confirmed by experience.
mn
1 Scope
This document provides calculation examples for different bevel gear designs regarding the scuffing
load capacity according to ISO/TS 10300-20. The initial geometry data of the gear necessary for these
calculations are in accordance with ISO 23509.
The term "bevel gear" is used to mean straight, helical (skew), spiral bevel, zerol and hypoid gear
designs. Where this document pertains to one or more, but not all, the specific forms are identified.
The formulae in this document are based on virtual cylindrical gears and restricted to bevel gears
whose virtual cylindrical gears have transverse contact ratios of ε < 2. The results are valid within
vα
the range of the applied factors as specified in ISO 10300-1 (see ISO 6336-2). Additionally, the given
relations are valid for bevel gears of which the sum of profile shift coefficients of pinion and wheel is
zero (see ISO 23509).
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO/TS 10300-20, Calculation of load capacity of bevel gears — Part 20: Calculation of scuffing load
capacity — Flash temperature method
3 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
4 Symbols
For the purposes of this document, the symbols and units given in ISO/TS 10300-20 apply.
5 Application
This document provides four sample calculations:
— Sample 1 is a rating of a spiral bevel gear pair without hypoid offset according to ISO/TS 10300-20
(see Annex A);
— Sample 2 is a rating of a hypoid gear set according to ISO/TS 10300-20 (see Annex B);
— Sample 3 is a rating of a hypoid gear set according to ISO/TS 10300-20 (see Annex C);
— Sample 4 is a rating of a hypoid gear set according to ISO/TS 10300-20 (see Annex D).
2 © ISO 2021 – All rights reserved

Annex A
(informative)
Sample 1: Rating of a spiral bevel gear pair without hypoid offset
according to ISO/TS 10300-20
A.1 Initial data
Sample 1 is for a spiral bevel gear pair without hypoid offset which uses Method 0 according to
ISO 23509 for calculation of gear geometry. The initial data for pitch cone parameters for this sample is
shown in Table A.1 and the input data for tooth profile parameters in Table A.2.
Table A.1 — Initial data for pitch cone parameters
Symbol Description Method 0 Method 1 Method 2 Method 3
Σ shaft angle 90° X X X
a hypoid offset 0 mm X X X
z number of teeth 14/39 X X X
1,2
d mean pitch diameter of wheel — — X —
m2
d outer pitch diameter of wheel 176,893 mm X — X
e2
b wheel face width 25,4 mm X X X
β mean spiral angle of pinion 35° X — —
m1
β mean spiral angle of wheel 35° — X X
m2
r cutter radius 114,3 mm X X X
c0
number of blade groups
z — — X X
(only face hobbing)
Table A.2 — Input data for tooth profile parameters
Data type I Data type II
Symbol Description Symbol Description
α 20°
dD
α 20°
dC
f 0
αlim
x — c 0,247 37
hm1 ham
k — k 2,000
hap d
k — k 0,125
hfp c
x — k 0,091 5
smn t
W —
m2
j 0,127 mm
et2
θ 2,134 2°
a2
θ 6,493 4°
f2
ρ 0,8 mm/0,8 mm
a01
ρ 1,2 mm/1,2 mm
a02
s 0 mm/0 mm
pr1D,C
s 0 mm/0 mm
pr2D,C
Table A.3 and Table A.4 show geometry and operational data and text for explanation.
Table A.3 — Geometry data from calculation according to ISO 23509
Symbol Description Values Symbol Description Value
mean pitch diameter 54,918 mm/ offset angle on
d ζ 0°
m1,2 mp
of pinion/wheel 152,987 mm pitch plane
mean addendum of pinion/ 4,836 mm/ pinion offset angle
h ζ 0°
am1,2 R
wheel 1,591 mm on root plane
mean dedendum of pinion/ 2,394 mm/ outer cone distance on
h R 93,973 mm
fm1,2 e1,2
wheel 5,639 mm pinion/wheel
effective pressure angle mean cone distance on
α 20°/20° R 81,273 mm
eD,C m1,2
for drive side/coast side pinion/wheel
generated pressure angle pitch angle 19,747°/
α 20°/20° δ
nD,C 1,2
for drive side/coast side on pinion/wheel 70,253°
face angle 26,240°/
α limit pressure angle 0° δ
lim a1,2
on pinion/wheel 72,387°
root angle 17,613°/
m mean normal module 3,213 mm δ
mn f1,2
on pinion/wheel 63,760°
thickness modification
basic crown gear deden- 0,037/
k 1,25 x coefficient on pinion/
hfp sm1,2
dum factor -0,055
wheel
pinion offset angle
ζ 0,000° m outer transverse module 4,536 mm
m et2
on axial plane
mean normal circular
6,465 mm/
s tooth thickness
mn1,2
3,511 mm
of pinion/wheel
Table A.4 — Operation parameters and additional considerations
Symbol Description Value
Additional data
wheel profile generated
roughing/finishing method face milling (ground)
b effective face width on wheel 08, 5⋅ b
2eff
profile crowning low
verification of contact pattern checked under light test load for each gear
mounting conditions of pinion and wheel one member cantilever−mounted
Operation parameters
T pinion torque 300 Nm
-1
n pinion rotational speed 1 200 min
K application factor 1,1
A
active flank drive
Run-In-Status Run-In
Material data for pinion and wheel (case hardened steel)
E modulus of elasticity 210 000 N/mm
ν Poisson’s ratio 0,3
σ allowable stress number (contact) 1 500 N/mm
H lim
σ nominal stress number (bending) 480 N/mm
F lim
ρ densitiy of pinion / wheel 7 800 kg/m (according to
M
ISO/TS 10300-20:2021, Table 5)
4 © ISO 2021 – All rights reserved

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