Haugweg 24
D-71711 Murr / Murr
Test for pad assemblies
2012 ECE-R90 Annex 9
PAGE 1
Release 13.06.2014
Item 2.2.2.2. KM
Commercial vehicles
Determination of friction behaviour
by machine testing as per
E/ECE/324/Rev.1/Add.89/Rev.3
E/ECE/TRANS/505/Rev.1/Add.89/Rev.3
Addendum 89: Regulation No. 90
Annex 9 – item 2.2.2.2.
Test schedule with constant torque (KM)
Recommended practice
Applicable on machines type : ♦ RWS60A
♦ RWS75A
♦ RWS75B
♦ RWS75C
♦ RWS100B
Krauss GmbH
Haugweg 24
D-71711 Murr
Tel. (+49)7141-788932-0 - Freiberg
Fax. (+49)7141-788932-19
E-Mail p.krauss@kraussgmbh.de
www.kraussgmbh.de
Index
No. Modifications
Page(s)
Date
Editor
1.
2.
3.
1-8
1-8
1&2
02.07.13
08.07.13
13.06.14
BP
PK
PK
New created
Updated
Pictures of parts & test setup included
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Haugweg 24
D-71711 Murr / Murr
Test for pad assemblies
2012 ECE-R90 Annex 9
PAGE 2
Release 13.06.2014
Item 2.2.2.2. KM
1. Application
For series control (batch control) purposes as per ECE-R90 Annex 9, the friction
coefficient is monitored by a partial lining test in a PV disc brake. This test is
related to the friction material quality and not to the geometrical dimensions of
the lining. The friction & temperature behaviour is tested on a Krauss-Friction
tester tye RW with corresponding features.
2. Test samples
a)
Caliper
Caliper MB SS60 – W123
Caliper type
Effective piston diameter
Piston surface
b)
Disc
MB SS60 – W123
Disc type
Disc rotor diameter
Disc rotor thickness.
Friction radius
Mass of rotor
c)
article part no.
Solid
D = 278
d = 12,8
rm=112
5,18
[mm]
[mm]
[mm]
[kg]
52 x 84 x 10
43,6
M1 = 191
M2 = 344
M3 = 357
[mm]
[cm²]
[Nm]
[Nm]
[Nm]
A123 421 00 12
Friction material sample
Sample size
Pad area
d)
article part no. 123 420 02 83
Rear – left hand side
60
[mm]
28,6
[cm²]
Testing torques +/- 5 %
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D-71711 Murr / Murr
b)
Test for pad assemblies
2012 ECE-R90 Annex 9
PAGE 3
Release 13.06.2014
Item 2.2.2.2. KM
Testing brake - Option 2 (not for use in machines type RWS60A)
Caliper
FN57
VW
Rotor disc VAG No. 8D0615301J
D=312 x 25
[mm]
ventilated
Friction radius
[mm]
Pad area
[cm2]
Testing speed
660 + / - 10
[/min]
Testing torques +/- 5 %
M1 = 330
[Nm]
M2 = 595
[Nm]
M3 = 620
[Nm]
3. Test setup – shwn with caliper SS60
Cooling
Temperature
detection
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Haugweg 24
D-71711 Murr / Murr
Test for pad assemblies
2012 ECE-R90 Annex 9
PAGE 4
Release 13.06.2014
Item 2.2.2.2. KM
4. Temperatur detection
a)
Sliding pin
Sensor
Introduced mainly for in car testing. Became popular also at test rigs.
+
No modification of original rotor required.
+
Fast set up.
+
Measuring at the center of the friction ring of rotor .
Can not be mended.
Friction at pin generates heat.
Brake dust can come in between pin and rotor.
(Isolating effect - wrong measurement)
Positionning
thermocouples pin
type
Correct setup
• Apply correct load to the pin (approx. 0,3 N) and verify if the temperature
displayed under room condition does not increse more than 5 °C when
the drive is running at 660 rpm.
• Angularity correct to be 90 °
• Clean brake dust between disc and pin.
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Haugweg 24
D-71711 Murr / Murr
Test for pad assemblies
2012 ECE-R90 Annex 9
PAGE 5
Release 13.06.2014
Item 2.2.2.2. KM
b)
Embedded Thermocouples
Sensor
Size of thermo couple
Embedding
at disc
brake rotors
Possibility 1 :
Possibiltiy 2 :
In centre of friction ring
In the friction surface hat side
Initially recommended for QC testing of drum brake rotors only.
1996 agreed as new standard also for disc brake rotors.
+
Precision.
+
Does not generate any heat.
+
Measuring at the center of the friction ring of rotor.
Modification of original rotor required.
(Drilling of holes - weakening structure of rotor)
Long set up.
Needs slip ring device.
Can not be mended.
Correct
setup
• Take care that thermocouple is not loose after embedding.
• Check for proper connection to measuring system
(connectors / slipring head must be closed etc.)
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Test for pad assemblies
2012 ECE-R90 Annex 9
Haugweg 24
D-71711 Murr / Murr
PAGE 6
Release 13.06.2014
Item 2.2.2.2. KM
5. Dics rotor conditionning
Prior to testing the rotor shall be mechanically cleaned. This can be done using
emery paper. If the thicknes of the rotor is less than the specification it must be
replaced.
6. Test procedure
Caclulation friction value
Md
µ=
2 x p x reff x Ak x η
Md
p
reff
AK
Toruqe measured
Brake pressure
Effektive friction radius
Effektive piston diameter
[Nm]
[bar]
[mm]
[mm]
Efficiency
η = 0,98 for fix caliper type SS60
η= 0,95 for floating caliper type FN 57
Test procedure
Braking time 5 sec
Inerval time 10 sec
Test speed n = 660 +/- 10 /min = constant.
No cooling during the test cycles – only dust extraction.
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PAGE 7
Test for pad assemblies
2012 ECE-R90 Annex 9
Haugweg 24
D-71711 Murr / Murr
Release 13.06.2014
Item 2.2.2.2. KM
7. Test sequences
Programm
group
Cycle
Brakings
Test torque
Md
TA
(°C)
TE*
(°C)
I. Bedding
1–6
5
M1
100
1. braking
<50°C
Bis 250
Main group
II.
µ K1
7
5
M2
40
Bis 350
III.
µ B1
8 – 10
5
M2
100
Bis 350
IV.
µ F1
11
10
M3
100
Bis 550
V.
µ B2
12 – 15
5
M2
100
Bis 350
VI.
µ F2
16
10
M3
100
Bis 550
VII.
µ B3
17 – 19
5
M2
100
Bis 350
VIII.
µ K2
20
5
M2
40
Bis 350
Total
110
*TE: Temperatures are approximate values which result from the programme. Pad wear
is to be determined by weighing and measuring, before and after every test run. Position
and number of pad wear measuring points are determined specifically for each project.
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Haugweg 24
D-71711 Murr / Murr
Test for pad assemblies
2012 ECE-R90 Annex 9
PAGE 8
Release 13.06.2014
Item 2.2.2.2. KM
8. Evaluation
Assesment
To calculate frictional results only the actual measured values must be used
and not any specified values.The following values must be determined from the
test program:
Constants needed for calculation (e.g. rW) must be taken from the drawing.
- Cold friction
- Service friction
- Fading friction
- Minimum friction
- Maximum friction
- Pad wear
a)
µk1; µk2
µB1; µB2, µB3
µF1; µF2
µmin
µmax
VB
Cold and service friction levels
To calculate cold and service friction levels, so-called "instant friction values"
must be used. These are calculated by averaging all test results from 1 brake
operation measured in a window ± 0.1s centred on the time "80% + 1s".
(see figure below).
Picture – Evaluation of cold and service friction values
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Haugweg 24
D-71711 Murr / Murr
Test for pad assemblies
2012 ECE-R90 Annex 9
PAGE 9
Release 13.06.2014
Item 2.2.2.2. KM
Cold friction values
Cold friction levels µk1; µk2 are the instant friction levels recorded for each first
brake operation in the first cycle of test program group II and the last cycle in
test program group VIII,respectively. All these cycles start at a brake
temperature of 40°C.
Service friction values
The service friction levels are the "instant friction levels" of the first brake
operation of each cycle, with 100°C initial temperature, in test program groups
III., V. and VII.
In each of the program groups III. and VII., three service friction levels are
determined; 4 levels are determined in group V. The individual results are then
combined into a mean result µB1, µB2, µB3 for each group.
b)
Minimal-, Maximal-, and Fading values
The evaluation of the minimum, maximum and fading friction levels is carried
out from the time "80% + 0,5s" until the "end of braking" signal is triggered by
the test stand computer. (see figure below).
Picture – Evaluation of cold min,- max- and fading values
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Haugweg 24
D-71711 Murr / Murr
Test for pad assemblies
2012 ECE-R90 Annex 9
PAGE 10
Release 13.06.2014
Item 2.2.2.2. KM
Min friction value
The minimum friction value µmin is the lowest friction value which occurs in the
test program groups II to VIII. ( apart from block IV and VI ), measured in each
case from the time "80% + 0,5 sec." to the end of each braking.
Max friction value
The minimum friction value µmin is the lowest friction value which occurs in the
test program groups II to VIII measured in each case from the time
"80% + 0,5 sec." to the end of each braking.
Fadin values
Fading friction values µF1& µF2 are the lowest friction levels recorded in the test
program groups IV. (fading 1) and VI. (fading 2) measured from the time "80% +
0,5s" to the end of each braking.
c)
d)
Other information
All observations made during and after the test (e.g. important smoke
development, pad separating from backing plate, cracking on the pad edges or
friction surface, break-outs, brake disc condition (hotspots, cracks) etc.) must be
noted.
Wear [g] / [mm]
The samples are measured and weighed before and after the test at 4 points.
1
2
3
4
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Haugweg 24
D-71711 Murr / Murr
Test for pad assemblies
2012 ECE-R90 Annex 9
PAGE 11
Release 13.06.2014
Item 2.2.2.2. KM
9. Test Report Sample for Brake Type SS60
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