Road vehicles -- Brake linings -- Compressive strain test methods

ISO 6310:2009 specifies a method for test and measurement of the compressive displacement of brake linings or brake pad assemblies due to loading and temperature. It also provides a test method to assess lining thermal swell and growth. ISO 6310:2009 applies to disc brake pad assemblies or coupon samples cut from the friction material.

Véhicules routiers -- Garnitures de freins -- Méthode d'essai de la compressibilité

General Information

Status
Published
Publication Date
23-Jun-2009
Current Stage
9093 - International Standard confirmed
Start Date
25-May-2020
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INTERNATIONAL ISO
STANDARD 6310
Third edition
2009-07-01
Road vehicles — Brake linings —
Compressive strain test methods
Véhicules routiers — Garnitures de freins — Méthode d'essai de la
compressibilité
Reference number
ISO 6310:2009(E)
ISO 2009
---------------------- Page: 1 ----------------------
ISO 6310:2009(E)
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© ISO 2009

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Published in Switzerland
ii © ISO 2009 – All rights reserved
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ISO 6310:2009(E)
Contents Page

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

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

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

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

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

4 Symbols and units................................................................................................................................ 2

5 Principles............................................................................................................................................... 3

5.1 General................................................................................................................................................... 3

5.2 Test method A — Coupon sample and/or airbrake pad.................................................................... 4

5.3 Test method B — Hydraulic disc brake pad assembly..................................................................... 4

6 Test apparatus ...................................................................................................................................... 4

7 Test stand specifications..................................................................................................................... 5

7.1 Loading .................................................................................................................................................. 5

7.2 Heated platen ........................................................................................................................................ 5

7.3 Loading ram .......................................................................................................................................... 5

8 Sampling................................................................................................................................................ 6

9 Test method........................................................................................................................................... 6

9.1 General set-up....................................................................................................................................... 6

9.2 Room temperature compressibility test............................................................................................. 6

9.3 Temperature transfer and thermal expansion measurements......................................................... 7

9.4 Hot compressibility test ....................................................................................................................... 7

10 Test device deflection compensation................................................................................................. 7

11 Verification of the test stand using reference samples.................................................................... 8

12 Test report ............................................................................................................................................. 8

Annex A (informative) Example test report.................................................................................................... 13

© ISO 2009 – All rights reserved iii
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ISO 6310:2009(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 6310 was prepared by Technical Committee ISO/TC 22, Road vehicles, Subcommittee SC 2, Braking

systems and equipment.

This third edition cancels and replaces the second edition (ISO 6310:2001), which has been technically

revised.
iv © ISO 2009 – All rights reserved
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ISO 6310:2009(E)
Introduction

The compressive response of a brake lining or pad is an important design parameter. It is useful for the

evaluation of brake fluid displacement during a brake application, brake-pedal travel and the propensity of the

brake for generating judder or noise. It is also part of the brake pad characterization and a parameter for

quality control.

The purpose of the test methods described in this International Standard is to evaluate the compressive

response or “compressibility” of friction materials or brake pad assemblies. The tests measure compressibility

at ambient and elevated temperatures. During the elevated temperature portion of the test, the thermal

transmission and response of the brake pad assembly are measured.
© ISO 2009 – All rights reserved v
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INTERNATIONAL STANDARD ISO 6310:2009(E)
Road vehicles — Brake linings — Compressive strain test
methods
1 Scope

This International Standard specifies a method for test and measurement of the compressive displacement of

brake linings or brake pad assemblies due to loading and temperature. It also provides a test method to

assess lining thermal swell and growth.

This International Standard applies to disc brake pad assemblies or coupon samples cut from the friction

material.
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, Road vehicles — Braking of automotive vehicles and their trailers — Vocabulary

3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 611 and the following apply.

3.1
compressibility

change in pad thickness or deflection, caused by a uniaxial compression load during the final loading cycle, to

the maximum test pressure, which is measured in the same direction as the compression force, perpendicular

to the friction surface
3.2
compressive strain

ratio of the reduction in thickness of the brake lining, due to the compression load, to its initial thickness, which

is measured in the direction of the application force, perpendicular to the friction surface

© ISO 2009 – All rights reserved 1
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ISO 6310:2009(E)
3.3
deflection

net deflection of the sample as a result of the subtraction of the deflection of the apparatus itself from the total

deflection measured by the apparatus
D = D − D
tot app
where
D is the total deflection measured by the apparatus;
tot
D is the deflection of the apparatus itself
app
3.4
friction material contact area
measure of the area of friction material that carries the test load

NOTE It is advisable that slots, chamfers and any other features be accounted for in determining A .

3.5
hot compressibility
400
compressibility with a heated platen temperature of 400 °C
3.6
temperature transfer

temperature rise at the backing plate of a brake pad assembly after the friction surface has been in contact

with the heating plate at (400 ± 10) °C for a given period at a given pressure
T = T − T
T 3 2
where
T is the final temperature of the backing plate during the hot test;
T is the initial temperature of the backing plate for the hot test
3.7
pad thermal growth

permanent change in thickness of the sample after the friction surface has been in contact with the heating

plate at (400 ± 10) °C for a given period at a given pressure and then cooled down to room temperature

3.8
pad thermal swell

change in thickness of the sample after the friction surface has been in contact with the heating plate at

(400 ± 10) °C for a given period at a given pressure
4 Symbols and units

Table 1 lists the symbols and corresponding units used in this International Standard.

2 © ISO 2009 – All rights reserved
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ISO 6310:2009(E)
Table 1 — Symbols and units
Symbol Definition Unit Accuracy
2 2
A friction material contact area cm 0,5 cm
C compressibility µm 1 µm
C hot compressibility µm 1 µm
400
d average thickness of coupon sample mm 0,1 mm
d pad growth or thermal expansion back at ambient temperature µm 1 µm
d pad swell or thermal expansion µm 1 µm
D net deflection of test sample µm 1 µm
D deflection of the test apparatus itself at p µm 1 µm
app A

D total deflection measured by the test apparatus at the maximum test pressure µm 1 µm

tot
e f
F pre-load MPa 1 %
e f
F test load MPa 1 %
g e f
p test pressure at sample contact area or unit area pressure MPa 1 %
h e f
p simulated hydraulic line pressure MPa 1 %
T test temperature of the heating plate for hot test °C ± 2 °C
T initial temperature of the backing plate for hot test °C ± 2 °C
T final temperature of the backing plate during hot test °C ± 2 °C
T temperature transfer °C 2 %
ε compressive strain at p — 0,000 2
pA A
D at p . Used in test method B.
Average of five measurements.
D − D .
tot app
No sample installed.
1 bar = 0,1 MPa.
1 % full-span accuracy.
Test method A.
Test method B.
D/d. Used in test method A.
5 Principles
5.1 General
The test measures either:
⎯ the compressive strain of a friction material coupon (test method A), or
⎯ the compressive deflection of a brake pad assembly (test method B).

Depending upon the type of sample, one of two alternative test methods is followed for applying the test load.

Test results from test method A and test method B should not be directly compared.

© ISO 2009 – All rights reserved 3
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ISO 6310:2009(E)
5.2 Test method A — Coupon sample and/or airbrake pad

Test method A loads a sample coupon to the force required to achieve a unit-area pressure at the contact

interface. Test method A can be used to assess pad materials for drum brake assemblies, commercial vehicle

disc or drum brakes and material coupons for research and development purposes.

For large pads used on a commercial vehicle, measure the compressive strain at the left and the right halves

separately or use a segment cut in the radial direction. In other cases, sample sizes should be large enough to

account for material not being homogeneous. Surfaces of coupon samples should be flat and parallel.

Unless otherwise specified, report the compressive strain value, ε .
5.3 Test method B — Hydraulic disc brake pad assembly

Test method B loads the brake lining assembly to simulate a hydraulic line pressure of 10 MPa (100 bar) or

16 MPa (160 bar).

NOTE In common practice, the line pressure is expressed in bar in order to differentiate it from the face pressure at

the contact area. Test method B is typically used for passenger car and light truck hydrauli

...

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