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GB/T 41663-2022 English PDF (GBT41663-2022)

GB/T 41663-2022 English PDF (GBT41663-2022)

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GB/T 41663-2022: Road vehicles - Brake lining friction materials - Scale inertia dynamometer test method

This document specifies the test conditions and preparation, specimen items and procedures, and test reports of the scale inertia dynamometer test method for the brake lining friction materials of road vehicles. This document is applicable to the scale inertia dynamometer test of disc brake linings of passenger cars. On the basis of familiarity with the principle of scale reduction, this document may also be taken as a reference for the brake lining test of other types of vehicles. This document is applicable to raw material screening and inspection, early development of friction materials, quality control of production processes and test of foreign samples.
GB/T 41663-2022
NATIONAL STANDARD OF THE
PEOPLE REPUBLIC OF CHINA
ICS 43.040.40
CCS Q 69
Road Vehicles - Brake Lining Friction Materials - Scale
Inertia Dynamometer Test Method
ISSUED ON: JULY 11, 2022
IMPLEMENTED ON: FEBRUARY 1, 2023
Issued by: State Administration for Market Regulation;
Standardization Administration of the PEOPLE Republic of China.
Table of Contents
Foreword ... 3
Introduction ... 4
1 Scope ... 6
2 Normative References ... 6
3 Terms and Definitions ... 6
4 Symbols and Abbreviations ... 11
5 Test Conditions and Preparations ... 13
6 Test Items and Procedures ... 15
7 Test Report ... 19
Appendix A (informative) Technical Parameters of Scale Inertia Test Bench ... 21 Appendix B (informative) Technical Conditions of Cooling Air (environmental control system) of Scale Test ... 24
Appendix C (informative) Temperature Measurement Method of Scale Test ... 28 Appendix D (informative) Wear Measurement of Brake Lining and Brake Disc ... 29 Appendix E (informative) Technical Conditions of Scale Brake Disc ... 32 Appendix F (informative) Outline of Scale Test ... 34
Appendix G (informative) Examples of Test Report Format ... 36
Bibliography ... 38
Road Vehicles - Brake Lining Friction Materials - Scale
Inertia Dynamometer Test Method
1 Scope
This document specifies the test conditions and preparation, specimen items and procedures, and test reports of the scale inertia dynamometer test method for the brake lining friction materials of road vehicles.
This document is applicable to the scale inertia dynamometer test of disc brake linings of passenger cars. On the basis of familiarity with the principle of scale reduction, this document may also be taken as a reference for the brake lining test of other types of vehicles. This document is applicable to raw material screening and inspection, early development of friction materials, quality control of production processes and test of foreign samples. 2 Normative References
This document does not have normative references.
3 Terms and Definitions
The following terms and definitions are applicable to this document.
3.1 Scale Ratio
3.1.1 Scale ratio of effective friction radius
SRf
The ratio of the effective friction radius of the full-scale brake disc to the effective friction radius of the scale brake disc, which shall be calculated in accordance with Formula (1). Where,
Rf---the effective friction radius of the full-scale brake disc, expressed in (m); RfS---the effective friction radius of the scale brake disc, expressed in (m). 3.1.2 Scale ratio of brake lining area
ve---10% of the initial brake speed (v0), expressed in (km/h);
v0---the initial brake speed, expressed in (km/h);
25.92---the coefficient of unit conversion;
Se---the brake distance when the speed is 10% v0, expressed in (m);
Sb---the brake distance when the speed is 80% v0, expressed in (m).
NOTE: under the condition of deceleration braking, the calculation range of the mean fully developed deceleration is related to the release speed.
[source: GB/T 29064-2012, 3.4]
3.4 Braking Modes
3.4.1 Brake loading mode
3.4.1.1 Constant input (line pressure) application mode
During the braking process, the line pressure remains unchanged at the set value. 3.4.1.2 Constant output (brake torque) application mode
During the braking process, the output brake torque remains at the set value, which is equivalent to constant deceleration braking.
3.4.2 Brake release mode
3.4.2.1 Brake stop
A braking mode that decreases the test speed to less than 0.5 km/h or even lower. NOTE: under the condition of constant output, perform a brake stop; the release speed may be set to 1 km/h ~ 2 km/h.
3.4.2.2 Brake snub
A braking mode that decreases the test speed to not lower than 5 km/h.
4 Symbols and Abbreviations
The following symbls and abbreviations are applicable to this document (see Table 1). During the scale test, the temprature and relative humidity of the cooling air shall be adjusted and controlled; during each braking process, the average temperature, relative humidity and cooling air speed shall be measured and recorded.
The technical parameters of the environmental control system are shown in Appendix B. NOTE: generally speaking, the control range of the cooling air is: 20 ???C ~ 25 ???C, and the relative humidity is: 60% ~ 65%.
5.1.7 Rotation speed between two brakes
During the cooling period between two brakes, the rotation speed of the test bench is 10 km/h; for the recession test, the waiting speed is the initial speed of the next brake. 5.1.8 Initial brake temperature
The initial brake temperature refers to the real-time temprature of the brake disc at the start of brake.
5.1.9 Test temperature measurement
In the center of the thickness of the brake disc, drill a 3.0 mm hole. Embed the K-type thermocouple at the position of the effective friction radius, see Appendix C. 5.1.10 Sensor calibration
Every year, a third-party measurement institution performs the calibration of sensors measuring rotation speed, temprature, pressure, torque, cooling air speed and humidity, and issues a calibration certificate. Usually, users can self-check and record the measurement system in accordance with the test condition.
5.1.11 Sample measurement
Before and after the test, measure the thickness and mass of the test sample and brake disc; calculate the thickness wear and mass wear during the test. See Appendix D for the measurment locations.
5.1.12 Data collection
During the test with the scale inertia test bench, the following data shall be automatically collected in real time:
---brake time;
---rotation speed of main shaft;
---brake line pressure;
---brake torque;
---brake disc temperature;
---cooling air tempreature;
---cooling air speed;
---relative humidity of cooling air;
---test procedures and number of brakes.
5.1.13 Technical requirements for scale brake disc
The brake disc of the scale test uses the same material as the brake disc of passenger cars. The technical conditions for the brake disc are shown in Appendix E.
In principle, a new brake disc shall be used for each test. If the brake disc needs to be repeatedly used, each side of the brake disc needs to be ground by 100 ???m; brake discs with a thickness of less than 8.5 mm shall not be used again.
5.1.14 Axial runout of scale brake disc working surface
After the scale brake disc is installed, the initial axial runout (LRO) of the working surface shall not exceed 20 ???m, and the measurement location is 5 mm away from the edge of the outer side of the brake disc. Before and after each test, measure and record the axial runout of the working surface of the brake disc.
5.2 Specimen Preparation
The specimens shall be prepared in accordance with the following requirements: ---the specimens shall be cut from the product (including metal backing); ---specimen size: width: 25???0.10???0.25 mm, length: 40???0.10???0.25 mm, thickness: ??? 18 mm (not lower than 8.5 mm);
---the surface of the specimens: maintain the original state of the product (including coating and ablation, etc.) and avoid contamination;
---the measurement of specimens and brake dics before the test: see Appendix D; the measurement is accurate to three decimal places;
---before the test, the specimens and the working surface of the brake discs shall be respectively photographed and recorded.
6 Test Items and Procedures
6.1 Inspection before Running-in
NOTE: after 200 times of running-in, the contact rate of the running-in surface shall be checked, and the requirement is not lower than 80%; if the requirement is not satisfied, then, increase the number of running-in.
6.4 Second Efficiency Test
Repeat the first efficiency test (6.2), but there are changes in the initial brake speed and number of brakes:
a) initial brake speed: 20 km/h, 50 km/h, 100 km/h, 130 km/h;
b) initial brake temperature: 80 ???C;
c) brake deceleration: 0.1 g ~ 0.8 g;
d) number of brakes: 32 (4 ??? 8).
6.5 First Re-running-in
Repeat the running-in test in 6.3, but the number of brakes is 35.
6.6 First Recession Recovery Test
6.6.1 Benchmark test
The benchmark test shall be performed in accordance with the following test conditions: a) initial brake speed: 50 km/h;
b) initial brake temperature: 80 ???C;
c) brake deceleration: 0.3 g;
d) number of brakes: 3.
6.6.2 Recession test
The recession test shall be performed in accordance with the following test conditions: a) initial brake speed: 100 km/h;
b) initial brake temprature (first brake): 60 ???C;
c) brake deceleration: 0.45 g;
d) brake cycle: 35 s;
e) number of brakes: 10.
NOTE: after the end of the recession test, immediately turn on the cooling air; the main shaft rotates at at speed equivalent to 50 km/h; after 120 s, start the recovery test. 6.6.3 Recovery test
The recovery test shall be performed in accordance with the following test conditions: a) initial brake speed: 50 km/h;
b) brake deceleration: 0.3 g;
c) brake cycle: 120 s;
d) number of brakes: 12.
6.6.4 Efficiency inspection
The efficiency inspection shall be performed in accordance with the following test conditions: a) initial brake speed: 100 km/h;
b) initial brake temperature: 60 ???C;
c) brake deceleration: 0.45 g;
d) number of brakes: 2.
6.7 Second Re-running-in
In accordance with the requirements of 6.5, perform the test.
6.8 Second Recession Recovery Test
In accordance with the requirements of 6.6, repeat the test, but the number of brakes for the recession test is 15.
6.9 Third Re-running-in
In accordance with the requirements of 6.5, repeat the test.
6.10 Third Efficiency Test
In accordance with the requirements of 6.4, repeat the test.
6.11 Measurement and Inspection after Test
6.11.1 The measurement of the samples and brake discs after the test is shown in Appendix D. Calculate the thickness wear and mass wear, accurate to three decimal places. 6.11.2 Check and record (photo) the surface condition of the samples and brake discs, and take pictures.
6.12 Test Phenomenon Record
Observe and record abnormal phenomena during the test, such as: noise, vibration and material transfer, etc.
6.13 Outline of Scale Test
Present the test procedure described above in a tabular format. See Appendix F for the format. 7 Test Report
7.1 Overview
The reporting mode and content of the test results depend on the user?€?s test purposes. The test report can be divided into tabular and graphical reports.
7.2 Table
7.2.1 Test information
At least include: test date, material, simulation model and brake parameters, test specifications, test inertia, scale ratio and test environment conditions (cooling air temprature and humidity settings).
7.2.2 Test data
7.2.2.1 The data to be included in the table for each brake includes: test serial No., initial brake speed and release speed, brake line pressure, brake torque, friction coefficient, initial temperature of brake disc and final brake temperature, brake time, brake distance, brake deceleration and MFDD; among them: torque, pressure, friction coefficient should include the maximum value, minimum value and average value.
7.2.2.2 In accordance with the test purposes, brake line pressure and brake torque stability coefficient, specific torque, as well as other data that the tester needs to grasp can also be calculated and listed.
7.2.3 Summary table of test results
The content of the summary table can be selected and processed from the test data in accordance with the requriements of the tester or client:
---average friction coefficient: the average value of friction coefficients of different test procedures or the whole process;
---friction coefficient of key points: key points of efficiency test, minimum friction coefficient of recession test, etc.;
---brake temperature of key points: maximum temperature (final brake temperature) of

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