Road vehicles -- Brake lining friction materials -- Standard wear test procedure for commercial vehicles with air brakes

ISO 26866:2009 applies to commercial vehicles with air brakes in the categories M2, M3, N2, N3, O3, and O4, as specified in UNECE R.E.3. ISO 26866:2009 applies during product development, product prototypes, product specification or validation, and ongoing series production, as defined in ISO 15484.

Véhicules routiers -- Matériaux de friction pour garnitures de freins -- Méthode normale d'essai d'usure pour véhicules industriels équipés de systèmes de freinage pneumatiques

General Information

Status
Published
Publication Date
10-Nov-2009
Current Stage
6060 - International Standard published
Start Date
05-Nov-2009
Completion Date
11-Nov-2009
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INTERNATIONAL ISO
STANDARD 26866
First edition
2009-12-01
Road vehicles — Brake lining friction
materials — Standard wear test
procedure for commercial vehicles with
air brakes
Véhicules routiers — Matériaux de friction pour garnitures de freins —
Méthode normale d'essai d'usure pour véhicules industriels équipés de
systèmes de freinage pneumatiques
Reference number
ISO 26866:2009(E)
ISO 2009
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ISO 26866:2009(E)
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© ISO 2009

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ii © ISO 2009 – All rights reserved
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ISO 26866:2009(E)
Contents Page

Foreword ............................................................................................................................................................iv

Introduction.........................................................................................................................................................v

1 Scope......................................................................................................................................................1

2 Normative references............................................................................................................................1

3 Terms and definitions ...........................................................................................................................1

4 Symbols..................................................................................................................................................2

5 Sampling.................................................................................................................................................2

6 Test method ...........................................................................................................................................2

6.1 Principle..................................................................................................................................................2

6.2 Test equipment and parts.....................................................................................................................3

6.3 Test conditions ......................................................................................................................................3

6.4 Wear measurement methods ...............................................................................................................4

6.5 Test procedure for disc brake systems ..............................................................................................5

6.6 Test procedure for drum brake systems.............................................................................................6

6.7 Expression of results............................................................................................................................7

7 Test report..............................................................................................................................................7

7.1 Report for disc brakes ..........................................................................................................................7

7.2 Report for drum brakes.........................................................................................................................7

7.3 Lining data sheet .................................................................................................................................12

© ISO 2009 – All rights reserved iii
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ISO 26866:2009(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.

International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.

The main task of technical committees is to prepare International Standards. Draft International Standards

adopted by the technical committees are circulated to the member bodies for voting. Publication as an

International Standard requires approval by at least 75 % of the member bodies casting a vote.

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.

ISO 26866 was prepared by Technical Committee ISO/TC 22, Road vehicles, Subcommittee SC 2, Braking

systems and equipment.
iv © ISO 2009 – All rights reserved
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ISO 26866:2009(E)
Introduction

The huge variety of wear tests introduced by different truck and trailer manufacturers is highly time-consuming

and leads to multiple evaluations of the same pad material on the same application. In view of the fact that

test procedures are different, results do not correspond with each other.

Wear testing in general is very time-consuming and hence very costly. This International Standard has been

developed in an effort to characterize friction materials that are used for a wide array of applications. Being a

block wear schedule that comprises different energy and temperature levels, it provides a good general

characterization of the wear behaviour of a friction material.

This International Standard standardizes all different procedures into one single procedure that covers all

wear requirements of interest whilst having a minimum testing duration.

In the process of harmonizing commercial vehicle applications, the standardization of performance testing

friction materials is a top priority.

The varied conditions under which the friction material is tested and evaluated ensures a wide spectrum of

data, which is critical during the various phases of product life, such as product and manufacturing process

development, production validation, quality control, product auditing and field issues evaluation.

This International Standard is intended to be used in conjunction with other applicable standards or test

procedures (ISO, SAE, JIS/JASO, Federal Codes or Regulations, and other project or company-specific

testing programmes) to fully assess the adequacy of a friction material for use in a certain application, market

or vehicle platform. This International Standard does not include performance requirements related to

stopping distance or braking force distribution, under different vehicle conditions of speed, temperature, tyre-

to-road adhesion, loads and operating conditions of the braking system, as indicated in Federal Codes or

Regulations.

This International Standard has been developed as part of the friction material global harmonization

programme outlined in ISO 15484, and results from close collaboration with major car manufacturers, brake

system and component manufacturers, leading testing services, and standards development organizations

such as SAE and JIS/JASO.
© ISO 2009 – All rights reserved v
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INTERNATIONAL STANDARD ISO 26866:2009(E)
Road vehicles — Brake lining friction materials — Standard
wear test procedure for commercial vehicles with air brakes
1 Scope

This International Standard applies to commercial vehicles with air brakes in the categories M2, M3, N2, N3,

O3, and O4, as specified in UNECE R.E.3.

This International Standard applies during product development, product prototypes, product specification or

validation, and ongoing series production, as defined in ISO 15484.
2 Normative references

The following referenced documents are indispensable for the application 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.
UNECE R.E.3, Consolidated resolution on the construction of vehicles

ISO 611:2003, Road vehicles — Braking of automotive vehicles and their trailers — Vocabulary

ISO 1176, Road vehicles — Masses — Vocabulary and codes
ISO 3833, Road vehicles — Types — Terms and definitions

ISO 11157:2005, Road vehicles — Brake lining assemblies — Inertia dynamometer test method

ISO 15484:2008, Road vehicles — Brake lining friction materials — Product definition and quality assurance

3 Terms and definitions

For the purposes of this document, the terms and definitions given in UNECE R.E.3, ISO 611, ISO 1176,

ISO 3833, ISO 15484 and the following apply.
3.1
air brake system

braking system in which control and energy are transmitted from the point of application to the foundation

brakes by air/pneumatic transmission devices
3.2
axle load

technically feasible maximum design total mass specified by the vehicle or axle manufacturer and

acknowledged by the technical services

NOTE This mass can exceed the “maximum authorised total mass” permitted by national regulations. Unless

otherwise specified by the test requestor, the axle loads indicated in Table 1 are used to determine the test inertia.

© ISO 2009 – All rights reserved 1
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ISO 26866:2009(E)
3.3
brake type

brake sizes determined by the nominal rim diameter code, in accordance with Table 1

NOTE The same nominal rim diameter can have different tyre dynamic rolling radiuses. For other nominal rim sizes

or tyre dynamic radiuses, refer to the test requestor.
3.4
brake temperature

temperature measured on the disc or drum at the centre of the path followed by the lining

NOTE The brake temperature is measured using embedded thermocouples, located in the centre of the friction area

about (0,5 ± 0,1) mm below the disc/drum surface.
3.5
test inertia

part of the total inertia of the vehicle braked by the wheel under consideration, in accordance with Table 1

NOTE For other loads or tyre sizes, see ISO 11157.
3.6
wheel load
half of the axle load (3.2)
3.7
total wear

average of all measurement locations per pad or lining, added to the value of all pads and linings per brake

NOTE Standardized wear rate is based on a total number of 250 stops per step.
4 Symbols
Symbol Definition Unit
T Room temperature °C
T Initial temperature at beginning of braking °C
start
V Speed at end of braking km/h
end
V Initial speed at beginning of braking km/h
start
5 Sampling

Unless otherwise specified by the test requestor, sampling shall have been conducted in accordance with

ISO 15484:2008, 5.3.
6 Test method
6.1 Principle

This International Standard uses a single- or double-ended brake inertia-dynamometer to conduct the test.

The inertia-dynamometer provides a computer-controlled method to perform the test sequence controlling the

different parameters in order to ensure the accurate and repeatable evaluation of the different tests. The

control system of the inertia-dynamometer also records the in-stop values that allow the subsequent

generation of a complete test report to the requestor.
2 © ISO 2009 – All rights reserved
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ISO 26866:2009(E)
6.2 Test equipment and parts

6.2.1 An inertia-dynamometer having the characteristics specified in 6.2.2 to 6.2.4 shall be used for the test.

6.2.2 The inertia-dynamometer shall be capable of generating as close as possible, with a tolerance of

±5 %, the inertia specified in 6.3.1 or the test inertia indicated by the test requestor.

6.2.3 The brake fitted shall be identical to the intended use type and oriented as close as possible to the

vehicle mounting position. Inconsequential changes to the lining configuration are permitted (i.e. chamfers,

slots, wear indicators, noise shims, etc.)

6.2.4 The instrumentation for the test shall be capable of providing at least the following data:

a) continuous recording of disc or drum rotational speed;
b) the number of revolutions completed during a brake application;
c) the stopping time;

d) continuous recording of the temperature on the disc and pads or the drum and lining;

e) continuous recording of control line pressure or force during a brake application;

f) continuous recording of brake output torque.
6.3 Test conditions

6.3.1 Test inertia and tyre dynamic rolling radius shall be in accordance with Table 1.

Table 1 — Test conditions
Tyre dynamic
Test inertia
Axle load
Brake
a rolling radius
Remarks
Brake type
manufacturer 2
kg·m
All 22,5” 10 000 0,527 1 389 —
All 19,5” 9 000 0,518 1 207 Trailers
All 19,5” 9 000 0,446 895 Trucks
All 17,5” 6 600 0,407 547 —

The brake chamber shall be selected in coordination with the brake manufacturer.

6.3.2 The initial rotational speed of the inertia-dynamometer shall correspond to the test speeds as

specified in 6.5, and shall be based on the tyre dynamic rolling radius.

6.3.3 Cooling air at ambient temperature may be used, directly perpendicular to the axis of rotation of the

brake. Use the maximum cooling air speed of the system to reduce testing time. Make sure that the initial

braking temperature is achieved properly. Record and report the cooling air conditions, ambient temperature

and humidity (absolute or relative) values during the test.

6.3.4 When the rotor or drum temperature is below the initial temperature required for the brake application,

dra
...

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