QC/T 239-2015 PDF English
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Specifications and bench test methods for commercial vehicle service brake
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Performance Requirements for Truck & Bus Brakes
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QC/T 239-2015: Specifications and bench test methods for commercial vehicle service brake---This is an excerpt. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.), auto-downloaded/delivered in 9 seconds, can be purchased online: https://www.ChineseStandard.net/PDF.aspx/QCT239-2015
T24
INDUSTRY STANDARD
QC/T 239-2015
Replacing QC/T 239-1997 and QC/T 479-1999
Specifications and Bench Test Methods
for Commercial Vehicle Service Brake
Issued on. APRIL 30, 2015
Implemented on. OCTOBER 1, 2015
Issued by Ministry of Industry and Information Technology of
the People's Republic of China
QC
Table of Contents
Foreword... I
1 Scope... 1
2 Normative References... 1
3 Terminologies and Definitions... 1
4 Performance Requirements... 4
5 Relevant Requirements for Test... 6
6 Test Preparation... 7
7 Test Methods and Conditions... 8
Appendix A (Normative) Evaluation Method of Braking Torque... 14
1 Scope
This standard specifies the terminologies and definitions, performance requirements as
well as bench test methods of commercial vehicle service brake assembly.
This standard applies to the service brake assembly for Categories M2, M3 and N
vehicles specified in GB/T 15089 as well as friction lining (brake block) assembly. The brake
assembly for Category O vehicles may also refer to the provisions of this standard.
2 Normative References
The following documents for the application of this document are essential. Any dated
reference, just dated edition applies to this standard. For undated references, the latest edition
(including any amendments) applies to this standard.
GB/T 5620 Road Vehicles - Braking of Automotive
Vehicles and Their Trailers – Vocabulary
GB/T 15089 Classification of Power - Driven Vehicles and
Trailers
QC/T 556 Automotive Brake - Temperature
Measurement and Thermocouple Attachment
3 Terminologies and Definitions
For the purposes of this standard, the terminologies and definitions specified in GB/T
5620 and the following ones apply.
3.1
Braking period
The time from stating a braking to the next braking in a continuous braking procedure.
Note. braking period is expressed in second (s).
3.2
Initial braking temperature
The temperature of brake drum (disc) or friction lining (brake block) at the beginning of
braking.
Note. initial braking temperature is expressed in ℃.
3.3
Average braking torque
The ordinate value obtained by dividing the area enclosed by braking torque and braking
time by the active braking time during a braking, see Appendix A.
Note. average braking torque is expressed in N·m.
3.4
Maximum braking torque
The maximum value of braking torque on longitudinal coordinate on the curve changing
with braking time within the active braking time during a braking, see Mmax in Appendix A.
Note. the maximum braking torque is expressed in N·m.
4 Performance Requirements
4.1 Brake performance test
4.1.1 The first efficiency test.
4.1.2 The first normal temperature efficiency test.
Tested according to 7.1.4, the average braking torque value of its sample under the
specified braking pressure shall not be less than 75 % of the average braking torque value
under the same braking pressure of the corresponding initial braking speed in the second
efficiency test.
4.1.3 The second efficiency test.
4.1.3.1 Tested according to 7.1.5, when the initial braking speed is 60km/h (80km/h for
Category N1 vehicles), the average braking torque value of its sample under the specified
braking pressure shall be within the design upper and lower limits, when design upper and
lower limits are not required, it shall be within the scope of 90% ~ 120%; the stability for
braking torque shall not be less than 0.80.
4.1.4 The first fade recover test.
4.1.4.1 Tested according to 7.1.7, the fade rate of its sample shall be within the scope of
-20 % ~ 40%, and the absolute value of the recover rate shall not be larger than 20%.
4.1.4.2 The average braking torque value of thermal braking efficiency test shall not be less
than 60% of that under the equivalent conditions in the second efficiency test.
4.1.4.3 At the end of the test, brake shall work normally, and shall not have obvious
dragging.
4.1.5 The third efficiency test.
The same as 4.1.3.
4.1.6 The second fade test.
4.1.7 The second normal temperature efficiency test.
The average braking torque value of sample under the specified braking pressure shall
not be less than 75% of the average braking torque value under the same braking pressure in
the fourth efficiency test.
4.1.8 The fourth efficiency test.
The same as 4.1.3.
4.1.9 Braking noise requirements.
During the test process in 7.1, when measurement is conducted according to 5.2.4, the
braking noise of the samples for Categories M2, M3 and N1 vehicles shall be less than 80dB
(A), while that of the samples for other categories shall be less than 85dB(A).
4.2 Brake wear test
4.2.1 Wear requirements.
4.2.1.1 The wear requirements for brake friction lining (brake block) and brake drum (disc)
shall be subject to negotiation between supplier and purchaser.
4.2.1.2 After the whole wear test is finished, friction lining (brake block) and brake drum
(disc) shall meet the following requirements.
4.2.2 Braking efficacy inspection.
Compared with that before wear test, the average braking torque variation under the
specified braking pressure shall not exceed ±15%.
5 Relevant Requirements for Test
5.1 Test equipment requirements
5.1.1 The test equipment is inertia brake test bench (both single-wheel and double-wheel are
allowed), its performance index shall meet the requirements of all tests in this standard.
5.1.4 The control error of braking pressure, braking torque and rotation speed of test bench
main shaft shall not be larger than ±3%. The relative error of rotational inertia (including the
inertia of test bench rotating part) shall not be larger than ±5%.
5.1.5 The test equipment shall be able to continuously record the following parameters, and
the measuring error shall meet the following requirements.
5.1.6 The device and thermocouple used for measuring the temperature of brake drum (disc)
or friction lining (brake block) shall meet the relevant requirements of QC/T 556.
5.1.7 For the instruments or meters indicating various parameters, the accuracy grade shall
not be lower than Grade 2.5.
5.2 Other requirements
5.2.1 All test speeds shall be rounded off to the integral multiple of 5.
5.2.2 Except for fade test and unless otherwise specified, the test cooling air velocity shall
be 11 m/s, and the temperature of cooling air shall be the room temperature.
5.2.3 Unless otherwise specified, the braking final velocity of all tests shall be zero.
5.2.4 During braking noise measurement, the sound pickup of sound level meter shall be
placed at the place within the rotation plane of the tested brake 500mm away from the right
above of brake rotation axis, and the sound pickup shall be installed in wind ball.
6 Test Preparation
6.1 Thermocouple shall be installed according to the relevant requirements in QC/T 556.
6.2 The rotation speed of test bench main shaft shall be converted according to Formula (6).
7 Test Methods and Conditions
7.1 Brake performance test
7.1.1 Inspection prior to running-in.
7.1.2 The first efficiency test.
7.1.2.1 The initial braking temperature is (80±2)℃.
7.1.2.2 For Category N1 vehicles, the initial braking speed is 50 km/h or 80 km/h; for other
categories of vehicles, it is 30km/h or 60 km/h.
7.1.3 The first running-in test.
7.1.3.1 The initial braking temperature shall not be larger than 120℃.
7.1.3.2 The initial braking speed is 50 km/h.
7.1.3.3 For Category N1 and Category M2 vehicles, the braking deceleration is 3.5m/s2; for
other categories of vehicles, it is 3.0m/s2.
7.1.4 The first normal temperature efficiency test.
7.1.4.1 The initial braking temperature shall not be larger than 50℃.
7.1.4.2 For Category N1 vehicles, the initial braking speed is 50 km/h; for other categories
of vehicle, it is 30 km/h.
7.1.4.3 The braking pressure is the same as that in the first efficiency test.
7.1.4.4 Record the initial braking speed, initial braking temperature, braking final
temperature, braking time, braking pressure and output braking torque of each braking.
7.1.5 The second efficiency test.
For vehicles with the maximum design speed less than 90 km/h, it's the same as 7.1.2.
For vehicles with the maximum design speed larger than or equal to 90 km/h, the initial
braking speed shall be increased by 80% Vmax (it shall not be greater than 120 km/h for
Category N1 vehicles; it shall not be greater than 100 km/h for Category M2 and Category N2
vehicles; it shall not be greater than 90 km/h for Category M3 and Category N3 vehicles), the
rest is the same as 7.1.2.
7.1.6 The second running-in test.
The braking times is 50, the rest is the same as 7.1.3.
7.1.7 The first fade recover test.
7.1.7.1 Reference test.
7.1.7.2 Fade test.
7.1.7.4 Recover test
a) For Category N1 and Category M2 vehicles, the initial braking speed is 50 km/h; for
other categories of vehicles, it is 30 km/h.
b) The braking pressure is the same as that in the reference test.
c) The braking period is 60 s.
d) The braking times is 15.If the initial braking temperature of the last recover test is
higher than 100℃, braking times may be added, however, the total braking times shall not be
larger than 20.
7.2.4 Wear test.
Wear test conditions are shown in Table 3.At the end of each temperature grade test,
measure the friction lining (brake block) thickness according to 7.2.2, and calculate its wear,
which is the arithmetic mean of each measuring point.
7.2.5 Braking efficiency inspection.
At the end of the wear test, running-in test shall be conducted according to 7.1.6, then
efficiency test shall be conducted according to 7.1.5.
Appendix A
(Normative)
Evaluation Method of Braking Torque
Schematic diagrams for brake test process and braking torque value are shown in Figure
A.1 and Figure A.2.
ICS 43.040.40
T24
INDUSTRY STANDARD
QC/T 239-2015
Replacing QC/T 239-1997 and QC/T 479-1999
Specifications and Bench Test Methods
for Commercial Vehicle Service Brake
Issued on. APRIL 30, 2015
Implemented on. OCTOBER 1, 2015
Issued by Ministry of Industry and Information Technology of
the People's Republic of China
QC
Table of Contents
Foreword... I
1 Scope... 1
2 Normative References... 1
3 Terminologies and Definitions... 1
4 Performance Requirements... 4
5 Relevant Requirements for Test... 6
6 Test Preparation... 7
7 Test Methods and Conditions... 8
Appendix A (Normative) Evaluation Method of Braking Torque... 14
1 Scope
This standard specifies the terminologies and definitions, performance requirements as
well as bench test methods of commercial vehicle service brake assembly.
This standard applies to the service brake assembly for Categories M2, M3 and N
vehicles specified in GB/T 15089 as well as friction lining (brake block) assembly. The brake
assembly for Category O vehicles may also refer to the provisions of this standard.
2 Normative References
The following documents for the application of this document are essential. Any dated
reference, just dated edition applies to this standard. For undated references, the latest edition
(including any amendments) applies to this standard.
GB/T 5620 Road Vehicles - Braking of Automotive
Vehicles and Their Trailers – Vocabulary
GB/T 15089 Classification of Power - Driven Vehicles and
Trailers
QC/T 556 Automotive Brake - Temperature
Measurement and Thermocouple Attachment
3 Terminologies and Definitions
For the purposes of this standard, the terminologies and definitions specified in GB/T
5620 and the following ones apply.
3.1
Braking period
The time from stating a braking to the next braking in a continuous braking procedure.
Note. braking period is expressed in second (s).
3.2
Initial braking temperature
The temperature of brake drum (disc) or friction lining (brake block) at the beginning of
braking.
Note. initial braking temperature is expressed in ℃.
3.3
Average braking torque
The ordinate value obtained by dividing the area enclosed by braking torque and braking
time by the active braking time during a braking, see Appendix A.
Note. average braking torque is expressed in N·m.
3.4
Maximum braking torque
The maximum value of braking torque on longitudinal coordinate on the curve changing
with braking time within the active braking time during a braking, see Mmax in Appendix A.
Note. the maximum braking torque is expressed in N·m.
4 Performance Requirements
4.1 Brake performance test
4.1.1 The first efficiency test.
4.1.2 The first normal temperature efficiency test.
Tested according to 7.1.4, the average braking torque value of its sample under the
specified braking pressure shall not be less than 75 % of the average braking torque value
under the same braking pressure of the corresponding initial braking speed in the second
efficiency test.
4.1.3 The second efficiency test.
4.1.3.1 Tested according to 7.1.5, when the initial braking speed is 60km/h (80km/h for
Category N1 vehicles), the average braking torque value of its sample under the specified
braking pressure shall be within the design upper and lower limits, when design upper and
lower limits are not required, it shall be within the scope of 90% ~ 120%; the stability for
braking torque shall not be less than 0.80.
4.1.4 The first fade recover test.
4.1.4.1 Tested according to 7.1.7, the fade rate of its sample shall be within the scope of
-20 % ~ 40%, and the absolute value of the recover rate shall not be larger than 20%.
4.1.4.2 The average braking torque value of thermal braking efficiency test shall not be less
than 60% of that under the equivalent conditions in the second efficiency test.
4.1.4.3 At the end of the test, brake shall work normally, and shall not have obvious
dragging.
4.1.5 The third efficiency test.
The same as 4.1.3.
4.1.6 The second fade test.
4.1.7 The second normal temperature efficiency test.
The average braking torque value of sample under the specified braking pressure shall
not be less than 75% of the average braking torque value under the same braking pressure in
the fourth efficiency test.
4.1.8 The fourth efficiency test.
The same as 4.1.3.
4.1.9 Braking noise requirements.
During the test process in 7.1, when measurement is conducted according to 5.2.4, the
braking noise of the samples for Categories M2, M3 and N1 vehicles shall be less than 80dB
(A), while that of the samples for other categories shall be less than 85dB(A).
4.2 Brake wear test
4.2.1 Wear requirements.
4.2.1.1 The wear requirements for brake friction lining (brake block) and brake drum (disc)
shall be subject to negotiation between supplier and purchaser.
4.2.1.2 After the whole wear test is finished, friction lining (brake block) and brake drum
(disc) shall meet the following requirements.
4.2.2 Braking efficacy inspection.
Compared with that before wear test, the average braking torque variation under the
specified braking pressure shall not exceed ±15%.
5 Relevant Requirements for Test
5.1 Test equipment requirements
5.1.1 The test equipment is inertia brake test bench (both single-wheel and double-wheel are
allowed), its performance index shall meet the requirements of all tests in this standard.
5.1.4 The control error of braking pressure, braking torque and rotation speed of test bench
main shaft shall not be larger than ±3%. The relative error of rotational inertia (including the
inertia of test bench rotating part) shall not be larger than ±5%.
5.1.5 The test equipment shall be able to continuously record the following parameters, and
the measuring error shall meet the following requirements.
5.1.6 The device and thermocouple used for measuring the temperature of brake drum (disc)
or friction lining (brake block) shall meet the relevant requirements of QC/T 556.
5.1.7 For the instruments or meters indicating various parameters, the accuracy grade shall
not be lower than Grade 2.5.
5.2 Other requirements
5.2.1 All test speeds shall be rounded off to the integral multiple of 5.
5.2.2 Except for fade test and unless otherwise specified, the test cooling air velocity shall
be 11 m/s, and the temperature of cooling air shall be the room temperature.
5.2.3 Unless otherwise specified, the braking final velocity of all tests shall be zero.
5.2.4 During braking noise measurement, the sound pickup of sound level meter shall be
placed at the place within the rotation plane of the tested brake 500mm away from the right
above of brake rotation axis, and the sound pickup shall be installed in wind ball.
6 Test Preparation
6.1 Thermocouple shall be installed according to the relevant requirements in QC/T 556.
6.2 The rotation speed of test bench main shaft shall be converted according to Formula (6).
7 Test Methods and Conditions
7.1 Brake performance test
7.1.1 Inspection prior to running-in.
7.1.2 The first efficiency test.
7.1.2.1 The initial braking temperature is (80±2)℃.
7.1.2.2 For Category N1 vehicles, the initial braking speed is 50 km/h or 80 km/h; for other
categories of vehicles, it is 30km/h or 60 km/h.
7.1.3 The first running-in test.
7.1.3.1 The initial braking temperature shall not be larger than 120℃.
7.1.3.2 The initial braking speed is 50 km/h.
7.1.3.3 For Category N1 and Category M2 vehicles, the braking deceleration is 3.5m/s2; for
other categories of vehicles, it is 3.0m/s2.
7.1.4 The first normal temperature efficiency test.
7.1.4.1 The initial braking temperature shall not be larger than 50℃.
7.1.4.2 For Category N1 vehicles, the initial braking speed is 50 km/h; for other categories
of vehicle, it is 30 km/h.
7.1.4.3 The braking pressure is the same as that in the first efficiency test.
7.1.4.4 Record the initial braking speed, initial braking temperature, braking final
temperature, braking time, braking pressure and output braking torque of each braking.
7.1.5 The second efficiency test.
For vehicles with the maximum design speed less than 90 km/h, it's the same as 7.1.2.
For vehicles with the maximum design speed larger than or equal to 90 km/h, the initial
braking speed shall be increased by 80% Vmax (it shall not be greater than 120 km/h for
Category N1 vehicles; it shall not be greater than 100 km/h for Category M2 and Category N2
vehicles; it shall not be greater than 90 km/h for Category M3 and Category N3 vehicles), the
rest is the same as 7.1.2.
7.1.6 The second running-in test.
The braking times is 50, the rest is the same as 7.1.3.
7.1.7 The first fade recover test.
7.1.7.1 Reference test.
7.1.7.2 Fade test.
7.1.7.4 Recover test
a) For Category N1 and Category M2 vehicles, the initial braking speed is 50 km/h; for
other categories of vehicles, it is 30 km/h.
b) The braking pressure is the same as that in the reference test.
c) The braking period is 60 s.
d) The braking times is 15.If the initial braking temperature of the last recover test is
higher than 100℃, braking times may be added, however, the total braking times shall not be
larger than 20.
7.2.4 Wear test.
Wear test conditions are shown in Table 3.At the end of each temperature grade test,
measure the friction lining (brake block) thickness according to 7.2.2, and calculate its wear,
which is the arithmetic mean of each measuring point.
7.2.5 Braking efficiency inspection.
At the end of the wear test, running-in test shall be conducted according to 7.1.6, then
efficiency test shall be conducted according to 7.1.5.
Appendix A
(Normative)
Evaluation Method of Braking Torque
Schematic diagrams for brake test process and braking torque value are shown in Figure
A.1 and Figure A.2.
......
Source: Above contents are excerpted from the full-copy PDF -- translated/reviewed by: www.ChineseStandard.net / Wayne Zheng et al.
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