QC/T 237-2022 English PDF (QCT237-2022)

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QC/T 237-2022: Bench test methods for the performance of automobile parking brake
QC/T 237-2022
QC
AUTOMOTIVE INDUSTRY STANDARD
OF THE PEOPLE’S REPUBLIC OF CHINA
ICS 43.040.40
CCS T 24
Replacing QC/T 237-1997
Bench test methods for the performance of automobile
parking brake
ISSUED ON: APRIL 08, 2022
IMPLEMENTED ON: OCTOBER 01, 2022
Issued by: Ministry of Industry and Information Technology of the People’s
Republic of China.
Table of Contents
Foreword ... 6
1 Scope ... 8
2 Normative references ... 8
3 Terms and definitions ... 8
4 Relevant test requirements ... 9
5 Test preparation ... 10
6 Test methods ... 11
Bench test methods for the performance of automobile
parking brake
1 Scope
This document specifies the terms and definitions, relevant test requirements, test
preparations, and test methods for automobile parking brake.
This document applies to automobile parking brake.
This document does not apply to the parking brake of semi-trailer towing vehicle.
2 Normative references
The following documents are normatively referenced in this document and are
indispensable for its application. For dated references, only the version corresponding
to that date is applicable to this document; for undated references, the latest version
(including all amendments) is applicable to this document.
GB/T 5620, Road vehicles - Vocabulary and definition for braking of automotive
vehicles and their trailers
QC/T 556, Automobile brake temperature measurement and thermocouple mounting
3 Terms and definitions
Terms and definitions determined by GB/T 5620, as well as the following, are
applicable to this document.
3.1 Initial brake temperature
The temperature of parking brake disc (drum) or brake lining (friction lining) when
braking is applied.
Note: The initial braking temperature is expressed in degrees Celsius.
3.2 Brake input point
The joint between the force applying mechanism on the parking brake test bench and
the parking brake operating mechanism.
3.3 Brake input
The input – acted on the brake input point – used for adjusting the output force.
3.4 Integral type A
The brake – mounted in the wheel brake – that shares the same brake lining assembly
as the service brake.
3.5 Integral type B
The brake – mounted in the wheel brake – that uses a special brake lining assembly.
3.6 Center type
The brake that is mounted on the transmission output shaft or transmission shaft.
4 Relevant test requirements
4.1 Requirements for test equipment
4.1.1 The test equipment is an inertial brake test bench, whose performance indicators
shall meet the test requirements of this document.
4.1.2 The brake input device of the test bench shall meet the brake input requirements
of various test conditions and keep stable.
4.1.3 The brake cooling device of the test equipment shall be able to make the wind
speed at the brake under test reach 11 m/s, and cover the entire brake assembly.
4.1.4 For the brake input, the relative error of measurement shall not exceed ±1%, and
the relative error of control shall not exceed ±3%; for parameters such as the braking
torque and the spindle speed of the test bench, the relative error of measurement shall
not exceed ±1%, and the relative error of control shall not exceed ±2%. The devices
and thermocouples for measuring the temperature of brake discs (drums) and brake
linings shall comply with the relevant regulations in QC/T 556; the relative error of its
measurement shall not exceed ±3°C, and the relative error of the moment of inertia
(including the inertia of the rotating part of the test bench) shall not exceed ±5%.
4.1.5 The accuracy grade of other instruments and meters for indicating and recording
various parameters shall not be lower than 1.5.
4.2 Other requirements
4.2.1 Unless otherwise specified, the final braking speed of all tests is zero.
4.2.2 Unless otherwise specified, during the test, the cooling wind speed is 11 m/s, the
cooling vehicle speed is 10 km/h, and the cooling air temperature is room temperature.
6.1.2.3 Use the constant input mode to conduct the test, and use the brake input where
the braking deceleration reaches 1.5 m/s2 (for integral type A and integral type B) or 1.0
m/s2 (for center type) to perform braking.
6.1.2.4 The number of braking is 5 times.
6.1.2.5 Record the brake disc (drum) speed, temperature, brake time, brake input and
output braking torque during each braking process.
6.2 The first static performance test
6.2.1 Carry out the test in the forward and backward directions of the vehicle,
respectively. The test speed shall not be higher than 40 r/min, and shall keep the spindle
speed as stable as possible.
6.2.2 The initial brake temperature shall not be higher than 60 °C.
6.2.3 Use the constant input method to conduct the test; adjust the brake input, and take
no less than 5 points for braking within the deceleration range of 0 m/s2 ~ 2.5 m/s2; the
deceleration intervals output by each braking point shall be as equal as possible, and
shall increase sequentially from low to high.
6.2.4 Record the brake disc (drum) speed, temperature, brake time, brake input and
output braking torque during each braking process.
6.3 The first dynamic performance test
6.3.1 Carry out the test in the forward direction of the vehicle, and the initial brake
speed is 30 km/h; for the parking brake with emergency braking function, one test speed
shall be added according to the following requirements:
a) M1 vehicles: the initial brake speed is 100 km/h;
b) M2 and M2 vehicles: the initial brake speed is 60 km/h;
c) N1 vehicles: the initial brake speed is 70 km/h;
d) N2 vehicles: the initial brake speed is 50 km/h;
e) N3 vehicles: the initial brake speed is 40 km/h.
6.3.2 The initial brake temperature is 80 °C ± 2 °C. When the initial brake temperature
cannot be reached, raise the temperature according to the running-in test conditions.
6.3.3 Use the constant input method to conduct the test; adjust the brake input; take at
least 5 points in the deceleration range of 0 m/s2 ~ 2.0 m/s2 or 0 m/s2 ~ 3.0 m/s2 (only
used for the test of increasing the test speed of the parking brake with emergency
braking function) for braking. The deceleration intervals output by each braking point
shall be as equal as possible, and shall increase sequentially from low to high.