QC/T 564-2018 English PDF (QCT564-2018)

This standard specifies the terms and definitions, performance requirements, test-related requirements, test preparations, test methods for passenger car service brake assemblies. This standard is applicable to the service brake assembly and friction lining (lining block) assembly, for the category M1 passenger car, which is specified in GB/T 15089.

QC/T 564-2018
QC
AUTOMOBILE INDUSTRY STANDARD
OF THE PEOPLE’S REPUBLIC OF CHINA
ICS 43.040.40
T 24
Replacing QC/T 564-2008
Performance requirements and test methods for
passenger car service brake
ISSUED ON: JULY 04, 2018
IMPLEMENTED ON: JANUARY 01, 2019
Issued by: Ministry of Industry and Information Technology of PRC
Table of Contents
Foreword ... 3
1 Scope ... 5
2 Normative references ... 5
3 Terms and definitions ... 5
4 Performance requirements ... 10
5 Test-related requirements ... 13
6 Test preparation ... 14
7 Test method ... 16
Appendix A (Normative) Braking torque value method ... 24
Performance requirements and test methods for
passenger car service brake
1 Scope
1.1 This standard specifies the terms and definitions, performance
requirements, test-related requirements, test preparations, test methods for passenger car service brake assemblies.
1.2 This standard is applicable to the service brake assembly and friction lining (lining block) assembly, for the category M1 passenger car, which is specified in GB/T 15089.
2 Normative references
The following documents are essential to the application of this document. For the dated documents, only the versions with the dates indicated are applicable to this document; for the undated documents, only the latest version (including all the amendments) is applicable 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 Automobile brake - Temperature measurement and thermocouple
mounting
3 Terms and definitions
The terms and definitions as defined in GB/T 5620, as well as the following terms and definitions, apply to this standard.
3.1
Braking period
In the continuous braking process, the elapsed time, from the beginning of this braking to the beginning of the next braking.
Note: The unit of braking period is s.
4.1.8 The third efficiency test
Same as 4.1.3.
4.1.9 Braking noise
During the test process of 7.1, the braking noise value of the sample shall be less than 76dB (A).
4.1.10 Sample requirements after test
After completing the test of 7.1, the brake shall work normally AND meet the following requirements:
a) There shall be no scratches on the working surface of the brake drum or brake disc;
b) There shall be no deformation on the brake base plate (brake caliper), that affects the braking performance;
c) The surface of the friction lining (lining block) shall be intact; there shall be no defects such as peeling off, scorching, etc.; but slight cracks are
allowed;
d) There shall be no separation of friction lining (lining block) from brake shoe (back plate);
e) The brake wheel cylinder (brake caliper) shall have no leakage.
4.2 Abrasion test of brake
4.2.1 Abrasion requirements
4.2.1.1 The abrasion of brake friction linings (lining block) and brake drums (disks) shall be negotiated between the supplier and the buyer.
4.2.1.2 After all abrasion tests are completed, the friction lining (lining block) and the brake drum (disc) shall meet the following requirements:
a) There shall be no obvious scratches on the working surface of the brake drum or brake disc;
b) The surface of the friction lining (lining block) shall be complete; there shall be no obvious defects, such as missing edges, bumps, pits, peeling off, cracks;
c) There shall be no separation of the friction lining (lining block) from the brake shoe (back plate);
d) The surface of the friction lining (lining block) shall not have cracks, which penetrate through the entire friction surface.
4.2.2 Inspection of braking performance
Compared with before the abrasion test, the change of average braking torque, under the specified braking pressure, shall not exceed ±15%.
5 Test-related requirements
5.1 Test equipment
5.1.1 The test equipment is an inertial brake test bench (both single and double wheels are acceptable). Its performance indicators shall meet the test
requirements of this standard.
5.1.2 The brake line pressure supply system of the test equipment shall meet the requirements of various brake working conditions, for the brake line pressure, AND be stable. The rate of pressure rise and fall of the brake line shall be controlled within the range of (25 ± 5) MPa/s.
5.1.3 The brake cooling device of the test equipment shall make the wind speed at the brake under test reach 11 m/s, AND cover the entire brake assembly. 5.1.4 The control error of brake pipeline pressure, braking torque, test bench's spindle speed shall not exceed ±3%. The relative error of the rotation moment of inertia (including the inertia of the rotating part of the test bench) shall not exceed ±5%.
5.1.5 The test equipment shall be able to continuously record the following parameters. The measurement error shall meet the following requirements: a) The braking output torque is ±1.0%;
b) The braking pressure is ±1.0%;
c) The spindle speed of the test bench is ±1.0%;
d) The braking time is ±0.01 s;
e) The temperature of the brake drum (disc) and brake lining (lining block) is ±3 °C, when the temperature is not higher than 300 °C; it is ±1.0%, when the temperature is higher than 300 °C.
5.1.6 The device and thermocouple, which are used for measuring the
temperature of the brake drum (disc) and friction lining (lining block), shall comply with the relevant requirements in QC/T 556.
5.1.7 The accuracy grade of the instrument or meter, which indicates each parameter, shall not be lower than grade 2.5.
5.2 Other requirements
5.2.1 All test vehicle speeds shall be rounded off to an integral multiple of 5. 5.2.2 Except for the fading test AND unless otherwise specified, during the test, the cooling wind speed is 11 m/s; the temperature of the cooling air is room temperature.
5.2.3 Unless otherwise specified, the vehicle speed, at the end of all braking tests, shall be less than 5 km/h
5.2.4 When measuring braking noise, the pickup head of the sound level meter shall be placed in the rotating plane of the brake to be tested, 500 mm right above the axis of rotation of the brake; the pickup head shall be equipped with a wind protection ball.
5.2.5 For all tests, which are carried out according to the brake deceleration control, it shall use the formula (12) to convert the brake deceleration into the braking torque control value of the test bench.
5.2.6 The radial runout of the brake drum, after installation (measured at the middle of the width direction of the friction surface of the brake drum), shall not be greater than 0.2 mm. The axial runout of the friction surface of the brake disc, after installation (measured at the effective radius of the brake disc), shall not be greater than 0.15 mm.
6 Test preparation
6.1 Thermocouple installation
Install the thermocouple, according to the relevant requirements in QC/T 556. 6.2 Determination of the spindle speed of test bench
The spindle speed of the test bench is determined according to formula (6): Where:
n - Spindle speed of the test bench, r/min;
V - Test vehicle speed, km /h;
7.1.2.3 Take no less than 5 points for the test, within the specified braking pressure range. The interval between the test points shall be as equal as possible. The maximum increase in braking pressure shall not be higher than 2 MPa. Each braking pressure, which is corresponding to each initial braking speed, is tested separately.
7.1.2.4 Record the initial braking speed, initial braking temperature, final braking temperature, braking time, braking pressure, output braking torque, for each test.
7.1.3 Running-in test
7.1.3.1 The initial braking temperature shall not be higher than 120 °C. 7.1.3.2 The initial braking speed is as follows:
a) 65 km/h when Vmax is not higher than 140 km/h;
b) 80 km/h when Vmax is higher than 140 km/h.
7.1.3.3 The braking deceleration is 3.5 m/s2.
Note: The invariable input method can also be used during the test, BUT the braking pressure shall be adjusted, according to the change of the braking torque, to ensure that the average braking deceleration is as close as possible to the required value.
7.1.3.4 The number of braking operations is 200 OR the contact area between the friction lining (lining block) and the brake drum (disc) reaches more than 80%.
7.1.3.5 Record the output braking torque and braking pressure, at least once every 20 operations.
7.1.4 The first room temperature efficiency test
7.1.4.1 The initial braking temperature shall not be higher than 45 °C. 7.1.4.2 The initial braking speed is 30%Vmax, BUT not higher than 80 km/h. 7.1.4.3 The braking pressure is the same as that of the first efficiency test. 7.1.4.4 Record the initial braking speed, initial braking temperature, final braking temperature, braking time, braking pressure, output braking torque, for each test.
7.1.5 The second efficiency test
For vehicles, whose Vmax is not higher than 125 km/h, it is the same as 7.1.2. For vehicles, whose Vmax is higher than 125 km/h, increase the initial braking speed of 80% Vmax, BUT not higher than 160 km/h.
7.1.6 The second running-in test
Except that the number of braking operations is 20, the rest is the same as 7.1.3. 7.1.7 Failure test of piping system (optional)
7.1.7.1 The initial braking temperature is (80 ± 2) °C.
7.1.7.2 The initial braking speed is 100 km/h.
7.1.7.3 The braking pressure is the same as the first efficiency test.
7.1.7.4 Record the initial braking speed, initial braking temperature, final braking temperature, braking time, braking pressure, output braking torque, for each test.
7.1.8 The third running-in test
Same as 7.1.6.
7.1.9 The first fading recovery test
7.1.9.1 Benchmark test
7.1.9.1.1 The initial braking temperature is (80 ± 2) °C.
7.1.9.1.2 The initial braking speed is 50 km/h.
7.1.9.1.3 The braking deceleration is 3 m/s2.
7.1.9.1.4 The number of braking operations is 3.
7.1.9.1.5 The recording parameters are the same as 7.1.2.4.
7.1.9.2 Fading test
7.1.9.2.1 The initial braking temperature during the first braking is (80 ± 2) °C. The initial braking speed and braking period are as shown in Table 3.
7.1.9.5 Test record
7.1.9.5.1 Record the initial braking speed, initial braking temperature, final braking temperature, braking time, braking pressure, output braking torque, for each test.
7.1.9.5.2 During the fading test, observe and record the burning smell, smoke and other abnormal phenomena of the friction lining (lining block), during which braking operations. If air resistance occurs, it shall record the number of braking operations, at the occurrence of air resistance, the temperature of the friction lining (lining block) during air resistance, the temperature of the brake fluid in the brake caliper or brake wheel cylinder.
7.1.9.6 Inspection after test
7.1.9.6.1 After the brake is cooled to room temperature, in the state of releasing the brake and without cooling, make the brake drum (disc) run continuously at a speed equivalent to 60 km/h, for 60 minutes. Record the temperature change of the brake at the same time.
7.1.9.6.2 After the test, when the brake is cooled to room temperature, check the friction lining (lining block) for cracks, coking, scorching; whether there is a bright film on the surface of the friction lining (lining block). Check the friction surface of the brake drum (disk) for scratches and cracks.
7.1.10 The fourth running-in test
Same as 7.1.6.
7.1.11 The second fading recovery test
Except that the number of braking operations in 7.1.9.2.2 is 15, the rest is the same as 7.1.9.
7.1.12 The fifth running-in test
Same as 7.1.6.
7.1.13 The second room temperature efficiency test
Same as 7.1.4.
7.1.14 The third efficiency test
Same as 7.1.5.
7.1.15 Final inspection
After the above test, allow the brake to cool to room temperature; then perform the following inspections AND take records:
a) Whether there are fractures, bumps, pits, cracks, peeling off, scratches, carbon deposits, scorching, on the surface of the friction lining (lining block);
b) Whether the friction lining (lining block) is separated from the brake shoe (back plate);
c) Whether the brake bottom plate (or brake caliper) is deformed; whether the brake wheel cylinder (or brake caliper) is leaking;
d) Whether there are cracks or scratches on the working surface of the brake drum (disk);
e) Other abnormal phenomena.
7.2 Brake abrasion test
7.2.1 Test sample
In principle, it shall use the samples after the completion of test in 7.1. 7.2.2 Thickness measurement of friction lining (lining block)
7.2.2.1 Measure the thickness of each friction lining (lining block), at the selected point, accurate to 0.01 mm. If necessary, measure the mass of the brake shoe assembly (lining block).
7.2.2.2 For drum brakes, each brake shoe assembly shall have no less than 6 measuring points; the schematic diagram of the measuring points is as shown in Figure 1. For disc brakes, each lining block shall have no less than 5 measuring points; the schematic diagram of the measuring points is as shown in Figure 2. If necessary, measure the inner diameter of the brake drum or the thickness of the brake disc; the measuring points shall not be less than 3. 7.2.2.3 The thickness and mass measurement of friction lining (lining block) should be completed, within 2 h after the brake has cooled to room temperature.