SIST ISO 11749:2015

SLOVENSKI STANDARD
SIST ISO 11749:2015
01-marec-2015
1DGRPHãþD
SIST ISO 11749:1997
Jermenski pogoni - Mnogoterni klinasti jermeni za avtomobilsko industrijo -
Preskus utrujenosti
Belt drive - V-ribbed belts for the automotive industry - Fatigue test
Transmissions par courroies - Courroies striées pour la construction automobile - Essai
de fatigue
Ta slovenski standard je istoveten z: ISO 11749:2014
ICS:
21.220.10 Jermenski pogoni in njihovi Belt drives and their
deli components
43.060.10 Blok motorja in notranji deli Engine block and internal
motorja components
SIST ISO 11749:2015 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST ISO 11749:2015

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SIST ISO 11749:2015
INTERNATIONAL ISO
STANDARD 11749
Second edition
2014-01-15
Belt drive — V-ribbed belts for the
automotive industry — Fatigue test
Transmissions par courroies — Courroies striées pour la construction
automobile — Essai de fatigue
Reference number
ISO 11749:2014(E)
©
ISO 2014

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SIST ISO 11749:2015
ISO 11749:2014(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2014
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Published in Switzerland
ii © ISO 2014 – All rights reserved

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SIST ISO 11749:2015
ISO 11749:2014(E)

Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Principle . 1
4 Apparatus . 1
5 Test room conditions . 2
6 Test method . 3
6.1 Test conditions . 3
6.2 Procedure . 3
7 Test report . 5
Bibliography .11
© ISO 2014 – All rights reserved iii

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SIST ISO 11749:2015
ISO 11749:2014(E)

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
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
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
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
constitute an endorsement.
For an explanation on the meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO’s adherence to the WTO principles in the Technical Barriers
to Trade (TBT) see the following URL: Foreword - Supplementary information
The committee responsible for this document is ISO/TC 41, Pulleys and belts (including veebelts),
Subcommittee SC 1, Friction.
This second edition cancels and replaces the first edition (ISO 11749:1995), which has been technically
revised. It also incorporates Amendment ISO 11749:1995/Amd.1:2003.
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SIST ISO 11749:2015
INTERNATIONAL STANDARD ISO 11749:2014(E)
Belt drive — V-ribbed belts for the automotive industry —
Fatigue test
1 Scope
This International Standard specifies a dynamic test method for the quality control of V-ribbed belts
(PK profile) which are used predominantly for accessory drive applications in the automotive industry.
The dimensional characteristics of the belts and of corresponding pulleys are the subject of ISO 9981.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
ISO 683-1, Heat-treatable steels, alloy steels and free-cutting steels — Part 1: Non-alloy steels for quenching
and tempering
ISO 6508-1, Metallic materials — Rockwell hardness test — Part 1: Test method (scales A, B, C, D, E, F, G, H,
K, N, T)
ISO 9981:1998, Belt drives — Pulleys and V-ribbed belts for the automotive industry — PK profile: Dimensions
3 Principle
Determination of the performance of a belt under specified conditions on a two-, three-, or four-pulley
test machine as described in Clause 4.
The shortest V-ribbed belt which can be tested on the four-pulley test machine (see Figure 1) is
approximately 1 000 mm. Belts with lengths between 800 mm and 1 000 mm inclusive can be tested
on the three-pulley test machine (see Figure 2). Shorter belts should be tested on the two-pulley test
machine (see Figure 3) as described in 6.2.1.2.
A number of conditions shall be agreed between the manufacturer and user, including the power to be
transmitted, the minimum acceptable life, in hours, and the number of times the belt can be retensioned.
Belt failure occurs when the belt no longer satisfies the agreed conditions.
4 Apparatus
4.1 Dynamic test machine, of robust design so that all components withstand, with virtually no
deflection, the stress to which they are subjected.
The test machine shall consist of the following (see Figures 1, 2, and 3).
4.1.1 Driving pulley, and suitable mechanism for driving it.
4.1.2 Driven pulley, to which a suitable power-absorption unit is connected (4.1.3).
4.1.3 Power-absorption unit, accurate and capable of calibration.
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SIST ISO 11749:2015
ISO 11749:2014(E)

4.1.4 Temperature control system.
4.1.5 Reverse bending idler pulley, only for four-pulley test machine (see Figure 1).
4.1.6 Device through which tension may be applied to the belt
a) in the case of the three- or four-pulley test machine layout, an idler and tensioner pulley (see
Figures 1 and 2), or
b) in the case of the two-pulley test machine layout, a movable pulley (see Figure 3).
4.1.7 Means of determining belt slip, to an accuracy of ±0,1 %. The layout of the pulley and the
direction of rotation are shown in Figures 1, 2, and 3.
In order to accommodate different lengths, the position of relevant driving and driven members, the
position of the idler pulley and its support (in the case of the three-pulley test machine), and the position
of the reverse bending idler pulley (in the case of the four-pulley test machine) shall be adjustable so that
the test layout of the pulleys is attainable for each belt length.
So that the tension can be satisfactorily applied to the belt, and in order to allow for belt stretch, the idler
pulley and its bearing assembly shall be free to slide, as necessary, in the support bracket along the line
of application of the tensioning force.
For the four-pulley test machine in such a case, the line of action of the tensioning force shall bisect the
belt layout at the idler pulley and at the reverse bending idler pulley, and shall lie in the plane through
the centre of the pulleys (see Figure 1).
For the three-pulley test machine in such a case, the line of action of the tensioning force shall bisect the
belt layout at the idler pulley, shall pass through the axis centre of the idler pulley, and shall lie in the
plane through the centre of the idler pulley (see Figure 2).
The two-pulley test machine shall be constructed so that one of the units (driven or driving) can be
moved to accommodate belt lengths of up to 800 mm. A method of locking the movable unit in position
for a given tension in the belt shall be provided. So that the tension can be satisfactorily applied to the
belt, and in order to allow for belt stretch, the line of action of the tensioning forc
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