ISO 13050:2022

INTERNATIONAL ISO
STANDARD 13050
Third edition
2022-03
Synchronous belt drives — Metric
pitch, curvilinear profile systems G, H,
R and S, belts and pulleys
Transmissions synchrones — Pas métrique, systèmes à denture
curviligne G, H, R et S, courroies et poulies
Reference number
© ISO 2022
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Published in Switzerland
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Contents Page
Foreword .v
1 Scope . 1
2 Normative reference .1
3 Terms and definitions . 1
4 Symbols . 1
5 Synchronous belt drive system types . .2
6 Belt nomenclature .3
7 Pulley nomenclature . .3
8 Profile system G . 4
8.1 Belt dimensions and tolerances . . 4
8.1.1 Belt tooth dimensions . 4
8.1.2 Belt widths and tolerances . 4
8.1.3 Pitch length measurement. 5
8.2 Pulleys, profile system G . 6
8.2.1 General . 6
8.2.2 Generating tool rack . 7
8.2.3 Pulley groove profile dimensions and tolerances . 9
8.2.4 Pulley outside diameters . 10
8.2.5 Pulley width . 12
9 Profile system H .13
9.1 Belt dimensions and tolerances . .13
9.1.1 Belt tooth dimensions .13
9.1.2 Belt widths and tolerances . 14
9.1.3 Pitch length measurement. 15
9.2 Pulleys, profile system H . 17
9.2.1 General . 17
9.2.2 Generating tool rack . 17
9.2.3 Pulley groove profile dimensions and tolerances . 21
9.2.4 Pulley outside diameters . 22
9.2.5 Pulley width . 25
10 Profile system R .27
10.1 Belt dimensions and tolerances . . 27
10.1.1 Belt tooth dimensions . 27
10.1.2 Belt widths and tolerances .28
10.1.3 Pitch length measurement.28
10.2 Pulleys, profile system R .30
10.2.1 General .30
10.2.2 Generating tool rack . 31
10.2.3 Pulley groove profile dimensions and tolerances . 32
10.2.4 Pulley outside diameters .34
10.2.5 Pulley width . 37
11 Profile system S .38
11.1 Belt dimensions and tolerances .38
11.1.1 Belt tooth dimensions .38
11.1.2 Belt widths and tolerances .39
11.1.3 Pitch length measurement.40
11.2 Pulleys, profile system S . 42
11.2.1 General . 42
11.2.2 Generating tool rack . 42
11.2.3 Pulley groove profile dimensions and tolerances . 43
iii
11.2.4 Pulley outside diameters .44
11.2.5 Pulley width .46
Annex A (informative) Belt pitch lengths and tolerances .48
Annex B (informative) Relationship between centre distance and belt pitch length .50
Annex C (informative) Pulley tolerances .52
Annex D (informative) Flange dimensions .55
Bibliography .56
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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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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
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
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www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 41, Pulleys and belts (including veebelts),
Subcommittee SC 4, Synchronous belt drives.
This third edition cancels and replaces the second edition (ISO 13050:2014), which has been technically
revised.
The main changes are as follows:
— in Formulae (1) and (2), “A ” has been added before the first square bracket;
o
— the formulae in the document have been renumbered and symbols are now used;
— the nomenclature has been changed in Tables 1 and 14, and Figures 1 and 11;
— belt width measurement methods were improved in 8.1.2, 9.1.2, 10.1.2, 11.1.2;
— total measuring forces are now for reference only in 8.1.3.2, 9.1.3.2, 10.1.3.2, 11.1.3.2;
— belt length measurement procedures were enhanced in 8.1.3.3, 9.1.3.3, 10.1.3.3, 11.1.3.3;
— the taper specification in Annex C was removed.
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.
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INTERNATIONAL STANDARD ISO 13050:2022(E)
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