GB/T 22309-2023 PDF in English
GB/T 22309-2023 (GB/T22309-2023, GBT 22309-2023, GBT22309-2023)
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| GB/T 22309-2023 | English | 275 |
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Road vehicles -- Brake linings -- Shear test method for disc brake pad and drum brake shoe assemblies
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| GB/T 22309-2008 | English | 125 |
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Road vehicles -- Brake linings -- Shear teat procedure for disc brake pad and drum brake shoe assemblies
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Standards related to (historical): GB/T 22309-2023
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GB/T 22309-2023: PDF in English (GBT 22309-2023) GB/T 22309-2023
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 43.040.40
CCS Q 69
Replacing GB/T 22309-2008
Road vehicles - Brake linings - Shear test method for disc
brake pad and drum brake shoe assemblies
ISSUED ON: DECEMBER 28, 2023
IMPLEMENTED ON: JULY 01, 2024
Issued by: State Administration for Market Regulation;
Standardization Administration of the People’s Republic of China.
Table of Contents
Foreword ... 3
Introduction ... 5
1 Scope ... 6
2 Normative references ... 6
3 Terms and definitions ... 6
4 Symbols ... 7
5 Sample preparation ... 7
6 Test equipment and fixtures ... 8
7 Test procedure ... 11
8 Calculation of results ... 11
9 Test report ... 12
Appendix A (Informative) Test flow chart ... 14
Appendix B (Informative) Format of test report ... 15
References ... 16
Road vehicles - Brake linings - Shear test method for disc
brake pad and drum brake shoe assemblies
1 Scope
This document describes the sample preparation, test equipment and fixtures, test
procedure, calculation of results and test report for the shear strength test method for
disc brake pad assembly and drum brake shoe assembly.
This document applies to the determination of shear strength of automotive disc brake
pad assembly and drum brake shoe assembly that are integrally molded, bonded, or
fitted using the two types of systems. This document is not applicable to the
determination of shear strength of riveted automobile brake pad (shoe) assemblies.
2 Normative references
The following documents are referred to in the text in such a way that some or all of
their content constitutes requirements 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 - Vocabulary and definition for braking of automotive
vehicles and their trailers
3 Terms and definitions
Terms and definitions determined by GB/T 5620, as well as the following, are
applicable to this document.
3.1
lining
Friction material component of the brake assembly.
3.2
bond area
Contact area between the lining and the back plate or shoe.
3.3
Note: During the test, the shear force loaded on the sample and the auxiliary pressure
acting on the sample are of inconsistent directions. If the groove is inclined or
higher than the back plate, the test results will be affected.
Figure 1 – Sample of drum brake shoe assembly segment
6 Test equipment and fixtures
6.1 Test equipment
6.1.1 The test equipment shall be a press or tensile machine or similar machine (such
as a shear testing machine) which applies sufficient shear force by driving the indenter.
6.1.2 The test equipment shall be provided with a recording device, which can correctly
record the instantaneous failure shear force.
6.1.3 The test equipment shall be capable of controlling the loading rate so that the
average loading rate is (4 500 ± 1 000) N/s (depending on the vehicle type being
evaluated). If a constant-speed crosshead testing machine is used, the crosshead speed
is (10 ± 1) mm/min. Record the category of control of the testing machine (loading rate
or crosshead speed) on the test report, so that the results can be compared between
different test equipment. Avoid any impact load during the test.
6.2 Test fixtures
6.2.1 General
The shear test fixture shall be able to hold the sample and be parallel to the indenter. To
avoid sharp edges, the part of the fixture in contact with the sample shall be rounded
with a radius of no more than 2 mm. If a specific radius is used, record it in the test
report to avoid deviation from the test procedure. If the surface area of the fixture
contains draft angles, indicate it in the test report.
6.2.2 Drum brake shoe assembly
6.2.2.1 The fixture shall be designed such that the indenter is in consistent contact with
the contour surface of the lining along the length direction and has a gap of (1 ± 0.2)
mm from the arc surface of the drum brake shoe (see Figure 2). For the lining bonded
or molded to the shoe, the maximum distance from the bonding surface shall be 0.2 mm.
c – surface load;
d – the minimum friction on the contact surface;
e – not greater than the thickness of the back plate.
Figure 3 – Disc brake pad test fixture
7 Test procedure
7.1 Carry out the test at room temperature of (23 ± 5) ℃. If testing under other
environmental conditions is required, an agreement shall be reached with the customer.
7.2 When a high-temperature shear test is required, the sample shall be placed in an
oven, heated evenly from room temperature to the test temperature within (30 ± 2)
minutes, and then taken out of the oven, which shall be completed within 60 s. The test
temperature of drum brake lining is (200 ± 10) ℃, and the test temperature of disc brake
pad is (300 ± 10) ℃.
7.3 Place the drum brake shoe or disc brake pad in the appropriate shear test fixture in
the direction indicated by the test (radial or tangential).
7.4 Apply load at the rate specified in 6.1 until the sample fails.
7.5 Record the failure load and express the residual area of the friction material after
the shear test of the disc brake pad or drum shoe as a percentage in accordance with the
provisions of Chapter 9. Evaluate the fracture surfaces at the uncut edge (2 mm from
the brake pad or shoe profile) and the core area, respectively. If there is any objection
to the visual evaluation, use the following reference scheme for analysis (optional):
-- Mix to prepare 1.0 L of reference solution: 80 g of CuSO4, 30 g of NaCl, 100 mL of
0.01 mol/L HCl (adding 0.364 6 g of HCl to 1 L of solution), add distilled water or
deionized water to make the total volume of the solution 1.0 L;
-- Immerse the back plate into the reference solution for 5 seconds;
-- Evaluate the fracture condition and record it as follows: When the reference solution
does not dye the broken surface brown, the material has broken; If there is bond
failure between the glue and the back plate, regular and uniform brown will appear
on the broken surface.
7.6 See Appendix A for the test procedure.
8 Calculation of results
8.1 Calculate the shear strength according to Formula (1):
8.2 Calculate A based on the friction material bonding profile instead of the pad surface,
and remove the grooves. Express the shear strength by the minimum value and the
average value of samples.
9 Test report
The test report (see Appendix B) shall include the following contents.
a) Product model, supplier and batch number of drum brake shoe assembly or disc brake
pad assembly.
b) Type of sample and direction of loading, when testing using a part of the assembly
or a prepared sample.
c) Number of samples.
d) Minimum and average values of shear force, or minimum and average values of shear
strength, or all of the above.
e) Fixture with/without draft angle.
f) Expression of the shear test results (evaluated with reference to the shear fracture
diagram in Figure 4), including the following information:
1) Failure percentage (smooth surface, bonding layer and lining layer);
2) Area and location of smooth surface area.
g) Test conditions different from those specified in Chapter 5, such as special test
temperature.
......
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
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