Codeofchina.com is in charge of this English translation. In case of any doubt about the contents of English translation, the Chinese original shall be considered authoritative.
This standard is developed in accordance with the rules given in GB/T 1.1-2009.
This standard was proposed by China Building Materials Federation.
This standard is under the jurisdiction of the National Technical Committee on Non-metallic Mineral Products of Standardization Administration of China (SAC/TC 406).
Road vehicles - Brake lining friction materials - Drag test method for friction performance
1 Scope
This standard specifies the test equipment, test types, test devices, test steps and result report of friction performance test of brake lining friction materials for road vehicles by drag method.
It is applicable to the friction performance test of brake linings for Categories M, N, O and L vehicles (hereinafter referred to as linings).
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.
GB/T 5620 Road vehicles - Braking of automotive vehicles and their trailers - Vocabulary (GB/T 5620-2002, idt ISO 611:1994)
GB/T 15089 Classification of power-driven vehicles and trailers
JB/T 7498 Coated abrasives - Abrasive paper
QC/T 556 Automotive brake - temperature measurement and thermocouple attachment
3 Terms and definitions
For the purpose of this standard, the terms and definitions specified in GB/T 5620 and GB/T 15089 as well as the following ones apply.
3.1
braking cycle
braking process consisting of several times of braking operations, each of which includes a 5s braking and a 10s idling
3.2
constant pressure mode
control mode to make the pressure of the line constant during the braking process
3.3
constant torque mode
control mode to make the braking torque constant during the braking process
3.4
initial brake rotor temperature
temperature of brake rotor when the first braking operation starts in each braking cycle
3.5
maximum brake rotor temperature
temperature that is not allowed to be exceeded by that of the brake rotor in each braking cycle
4 Test equipment
4.1 The test equipment shall be qualified to execute the preset test procedures and realize automatic control.
4.2 The record equipment shall be qualified to continuously record the following parameters, and the measuring accuracy shall meet the following requirements:
——±1.5% for output braking torque;
——±1.5% for input line pressure;
——±1.5% for temperature of brake rotor.
4.3 The temperature is cooled with air during the test, with the temperature of the air not exceeding 25℃ and the air flow blowing towards the brake at (600±60)m3/h.
4.4 The equipment spindle speed shall be (660±10)r/min for idling and not less than 600r/min for full load.
4.5 Embedded type thermocouple should be used to measure the temperature of the brake rotor during the test; thermocouple attachment and temperature measurement shall meet the requirements of QC/T 556. Other measuring devices and methods may also be used, however, the specified measuring accuracy requirements shall be meet.
4.6 Radial and axial runout of the brake rotor shall not exceed 0.08mm during the equipment operation.
5 Test types and devices
5.1 Test types
The test is of original sample method and sampling method. The former is testing on the original dimension samples and the latter is testing on the specified-dimension sample blocks made from the sample.
Either original sample method or sampling method may be adopted for the test of disc linings for Categories M1, M2, N1, O1, O2 and L vehicles.
Sampling method is adopted for the test of disc and drum linings for Categories M3, N2, N3, O3 and O4 vehicles.
5.2 Test devices of disc linings for Categories M1, M2, N1, O1, O2 and L vehicles
5.2.1 During the test by original sample method, the brake rotor and brake caliper shall be those meeting the requirements of the drawings and technical documents; the roughness of brake rotor friction surface shall be less than 15μm and the thickness shall not be less than 90% of its original thickness.
5.2.2 During the test by sampling method, a fixed disc brake caliper shall be installed on the testing machine with plunger stopper diameter of 36mm; the center of sample block is 116.5mm from the center of the brake rotor after installation. The brake rotor used in the test shall meet the following technical requirements:
a) the brake rotor is solid (not ventilated), whose diameter is (278±2)mm and thickness is (9±0.5)mm;
b) the material of the brake rotor body is HT250, whose rigidity of the friction surface is 180HBW to 250HBW.
5.3 Test devices of disc and drum linings for Categories M3, N2, N3, O3 and O4 vehicles
A fixed disc brake caliper shall be installed on the testing machine with plunger stopper diameter of 60mm; the center of sample block is 108mm from the center of the brake rotor after installation. The brake rotor used in the test shall meet the following technical requirements:
a) the brake rotor is solid (not ventilated), whose diameter is (278±2)mm and thickness is (12±0.5)mm;
b) the material of the brake rotor body is HT250, whose rigidity of the friction surface is 180HBW to 250HBW.
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 Test equipment
5 Test types and devices
6 Test steps
7 Result report
