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

ISO 26865:2009 applies to commercial vehicles of the categories M2, M3, N2, N3, O3 and O4, as defined in UNECE R.E.3, which are equipped with air brakes. ISO 26865:2009 applies during product development, product prototypes, product specification or validation, and ongoing series production, as defined in ISO 15484. When used in conjunction with other applicable standards or test procedures, ISO 26865:2009 is intended to provide a complete assessment of a friction material's adequacy for use in a certain application, market or vehicle platform. ISO 26865:2009 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. ISO 26865:2009 specifies a single-ended inertia-dynamometer performance procedure, which is intended to standardize the various procedures for commercial vehicles equipped with air brakes into one unique procedure covering all performance requirements of interest. The test sequence includes performance evaluation for the following conditions: performance test before and after bedding; brake fade after bedding and after moderate temperature; sensitivity to temperature, speed and pressure influence; downhill simulation; brake recovery.

Véhicules routiers -- Matériaux de friction pour garnitures de freins -- Mode opératoire d'essai des performances normalisées pour les véhicules utilitaires munis de freins à air comprimé

General Information

Status
Published
Publication Date
01-Mar-2009
Current Stage
6060 - International Standard published
Start Date
23-Feb-2009
Completion Date
02-Mar-2009
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INTERNATIONAL ISO
STANDARD 26865
First edition
2009-03-15
Road vehicles — Brake lining friction
materials — Standard performance test
procedure for commercial vehicles with
air brakes
Véhicules routiers — Matériaux de friction pour garnitures de freins —
Mode opératoire d'essai des performances normalisées pour les
véhicules utilitaires munis de freins à air comprimé
Reference number
ISO 26865:2009(E)
ISO 2009
---------------------- Page: 1 ----------------------
ISO 26865:2009(E)
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© ISO 2009

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ii © ISO 2009 – All rights reserved
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ISO 26865:2009(E)
Contents Page

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

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

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

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

3 Terms and definitions........................................................................................................................... 2

4 Symbols ................................................................................................................................................. 3

5 Sampling................................................................................................................................................ 3

6 Test method........................................................................................................................................... 3

6.1 Principle................................................................................................................................................. 3

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

6.3 Test conditions ..................................................................................................................................... 4

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

6.5 Test procedure for drum brake systems............................................................................................ 9

6.6 Expression of results ......................................................................................................................... 12

7 Test report ........................................................................................................................................... 13

7.1 Tabular report...................................................................................................................................... 13

7.2 Summary of results ............................................................................................................................ 13

7.3 Lining data sheet ................................................................................................................................ 13

© ISO 2009 – All rights reserved iii
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ISO 26865:2009(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 26865 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 26865:2009(E)
Introduction

The standardization of performance testing friction for commercial vehicle application is a major challenge for

technical groups around the world in their efforts to harmonize procedures.

The diverse conditions under which the friction material is tested and evaluated ensure a wide spectrum of

data, which is critical during the various phases of product life (i.e. product and manufacturing process

development; production validation; quality control; product auditing; field issues evaluation).

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

programme outlined in ISO 15484 and is the product of a close collaboration between major car

manufacturers, brake system and component manufacturers, leading testing services and standards

development organizations [e.g. SAE and JSAE (Japanese Society of Automotive Engineers)].

The introduction by various truck and trailer manufacturers of a wide range of performance tests has proven

time-consuming and has led to multiple evaluations of the same friction material for the same application. The

test results thus provided do not necessarily correspond with one another because the test procedures and

test conditions are not the same.
© ISO 2009 – All rights reserved v
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INTERNATIONAL STANDARD ISO 26865:2009(E)
Road vehicles — Brake lining friction materials — Standard
performance test procedure for commercial vehicles with air
brakes
1 Scope

This International Standard applies to commercial vehicles of the categories M2, M3, N2, N3, O3 and O4, as

defined in UNECE R.E.3, which are equipped with air brakes.

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

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

When used in conjunction with other applicable standards or test procedures, this International Standard is

intended to provide a complete assessment of a friction material’s adequacy for use in a certain application,

market or vehicle platform.

NOTE Applicable standards and test procedures include ISO, JIS/JASO (Japanese Industrial Standard/Japanese

Automotive Standards Organization), SAE (Society of Automotive Engineers), Federal Codes or regulations, and other

project or company-specific testing programmes.

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 specifies a single-ended inertia-dynamometer performance procedure, which is

intended to standardize the various procedures for commercial vehicles equipped with air brakes into one

unique procedure covering all performance requirements of interest.
The test sequence includes performance evaluation for the following conditions:
⎯ performance test before and after bedding;
⎯ brake fade after bedding and after moderate temperature;
⎯ sensitivity to temperature, speed and pressure influence;
⎯ downhill simulation;
⎯ brake recovery.
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.

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

© ISO 2009 – All rights reserved 1
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ISO 26865:2009(E)
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

UNECE R.E.3 (1999), Consolidated Resolution on the Construction of Vehicles
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 authorized total mass” permitted by national regulations. Unless

otherwise specified by the test requestor, the axle loads indicated in Table 2 are used to determine the test inertia.

3.3
brake type

brake sizes determined by the nominal rim diameter code in accordance with Table 2

NOTE The same nominal rim diameter can have different tyre dynamic rolling radius. Information pertaining to other

nominal rim sizes or tyre dynamic radius can be obtained from the test requestor.

3.4
brake temperature

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

3.5
test inertia

part of the total inertia of the vehicle braked by the wheel under consideration, in accordance with Table 2

NOTE For other loads or tyre sizes, see ISO 11157.
3.6
wheel load
half of the axle load (3.2)
2 © ISO 2009 – All rights reserved
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ISO 26865:2009(E)
4 Symbols
Table 1 — Symbols
Symbol Description Unit
d Mean fully developed deceleration (MFDD) m/s
I Test inertia kg⋅m
m Mass acting on the ground for the wheel(s) under consideration kg
M Brake measured torque N⋅m
p Brake actuating pressure bar
r Tyre dynamic rolling radius m
dyn
T Room temperature °C
T Temperature at end of braking °C
T Initial temperature at beginning of braking °C
V Velocity of the cooling air km/h
air
V Pad or lining wear mm, g
V Speed at the end of braking km/h
V Initial speed at beginning of braking km/h
V Rotor or drum wear mm, g
Percent difference between initial and minimum MFDD values during electrical and
∆ %
fade
computer engineering (ECE) fading steps

Duration of a braking cycle: time elapsing between the initiation of one brake application

∆ s
and the initiation of the next
5 Sampling

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

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

This International Standard uses a single-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 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.
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.

© ISO 2009 – All rights reserved 3
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ISO 26865:2009(E)

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) number of revolutions completed during a brake application;
c) 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 2.

Table 2 — Test conditions
Axle load r Test inertia
Brake dyn
Brake type Remarks
manufacturer 2
kg m kg⋅m
All 22,5” 10 000 0,527 1 389 —
All 19,5” 9 000 0,518 1 267 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 Table 3 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. The velocity of the cooling air over the brake, V , expressed in km/h, shall be as calculated in

air
Equation (1):
VV=×0,33 (1)
air I
where V is the initial speed at the beginning of braking, in km/h.

6.3.4 When required, heat up the brake to the required temperature by performing brake applications from

60 km/h to 20 km/h at 0,3 MPa brake pressure.
1) 1 bar = 0,1 MPa.
4 © ISO 2009 – All rights reserved
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ISO 26865:2009(E)
6.4 Test p
...

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