GB/T 44411-2024 PDF English
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| GB/T 44411-2024 | English | 275 |
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Testing methods of adhesion coefficient for motor vehicle inspection equipment and sites
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GB/T 44411-2024: Testing methods of adhesion coefficient for motor vehicle inspection equipment and sites
---This is an excerpt. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.), auto-downloaded/delivered in 9 seconds, can be purchased online: https://www.ChineseStandard.net/PDF.aspx/GBT44411-2024
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 43.180
CCS R 86
Testing methods of adhesion coefficient for motor vehicle
inspection equipment and sites
ISSUED ON: AUGUST 23, 2024
IMPLEMENTED ON: MARCH 01, 2025
Issued by: State Administration for Market Regulation;
Standardization Administration of the People’s Republic of China.
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Normative references ... 4
3 Terms and definitions ... 4
4 Test conditions ... 5
5 Test equipment ... 5
5.1 Test device for wheel adhesion coefficient ... 5
5.2 Test device for tractor adhesion coefficient ... 6
6 Test methods ... 7
6.1 Roller surface adhesion coefficient of roller reaction brake test bench ... 7
6.2 Free roller surface adhesion coefficient ... 8
6.3 Flat-plate brake test bench brake plate surface adhesion coefficient ... 9
6.4 Slide plate parking brake test device slide plate surface and inspection station ground
adhesion coefficient ... 9
6.5 Roller reaction brake test bench front and rear ground adhesion coefficient ... 9
6.6 Service brake road test lane adhesion coefficient ... 10
6.7 Traction parking brake inspection station road surface adhesion coefficient ... 10
6.8 Parking ramp surface adhesion coefficient ... 10
7. Processing of test results ... 11
Appendix A (Informative) Adhesion coefficient test record format ... 12
Bibliography ... 15
Testing methods of adhesion coefficient for motor vehicle
inspection equipment and sites
1 Scope
This document describes the testing methods of adhesion coefficient for motor vehicle
inspection equipment and sites, and specifies the technical requirements for test
conditions, test equipment and processing of test results.
This document applies to the testing of adhesion coefficient for inspection equipment
and sites of motor vehicle inspection and testing institutions.
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
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 8170-2008, Rules of rounding off for numerical values & expression and
judgment of limiting values
GB/T 42685-2023, Terminology of power-driven vehicle inspection
3 Terms and definitions
For the purposes of this document, the following terms and definitions, as well as those
given in GB/T 42685-2023, apply.
3.1
road test lane
Test lane used for road testing of motor vehicle service braking performance.
[Source: GB/T 42685-2023, 3.4.13]
3.2
parking ramp
Ramp used for road testing of motor vehicle parking braking performance.
Description of indexing numbers:
1 – object being tested;
2 – rubber layer;
3 – counterweight;
4 – tension sensor;
5 – traction rope;
6 – fixed pulley;
F – horizontal tension.
Figure 2 – Schematic diagram of the test device for traction adhesion coefficient
5.2.2 Technical requirements
5.2.2.1 The sum of the masses of the counterweight, rubber layer and tension sensor is
(40±2) kg.
5.2.2.2 Rubber layer: The rubber tires are of specification 225/50R18, which are cut,
laid flat and pasted together.
5.2.2.3 Tire rubber material: conventional tire (BR) butadiene rubber, Shore hardness
60 HA ~ 75 HA.
5.2.2.4 Tire pattern: The longitudinal pattern shall be consistent with the traction
direction (i.e., the direction of vehicle travel), and the tire pattern depth shall be no less
than 3.2 mm.
5.2.2.5 Rubber layer contact area: 200 mm × 140 mm.
5.2.2.6 Tension sensor measurement range: 0 N ~ 500 N, indication error: no more than
±1%.
5.2.2.7 The maximum value holding time of the display device shall not be less than 5
s.
6 Test methods
6.1 Roller surface adhesion coefficient of roller reaction brake test bench
6.1.1 Place the test wheel of the wheel adhesion coefficient test device on the upper
generatrix of the roller to be tested and apply a normal force to the test wheel in
accordance with the provisions of 5.1.2.1.
6.2.4 Repeat the test 6 times according to the method specified in 6.2.3 and calculate
the adhesion coefficient according to Formula (1).
6.2.5 Test the center and both ends (about 100 mm from the edge of the roller) of the
roller. For equipment in use, test the commonly used positions and the most severely
worn positions, and take the minimum value as the adhesion coefficient test result.
6.3 Flat-plate brake test bench brake plate surface adhesion coefficient
6.3.1 Place the rubber layer and counterweight of the traction adhesion coefficient test
device on the brake plate to be tested. Along the braking force test direction, gradually
apply a tensile force (F) parallel to the longitudinal geometric center line of the surface
of the plate to be tested to the tension sensor (see Figure 2). Read the maximum value
measured by the tension sensor when the rubber layer and the counterweight go from
static to relative slippage, which is the adhesion force.
6.3.2 Repeat the test 6 times according to the method specified in 6.3.1 and calculate
the adhesion coefficient according to Formula (3).
Where:
m – the sum of the masses of the counterweight, rubber layer and tension sensor, in
kilograms (kg);
g – acceleration due to gravity, taken as 9.80 m/s2.
6.3.3 Test the front, middle and rear positions of the brake plate surface. For equipment
in use, test the commonly used positions and the most severely worn positions, and take
the minimum value as the adhesion coefficient test result.
6.4 Slide plate parking brake test device slide plate surface and inspection station
ground adhesion coefficient
6.4.1 Test the adhesion coefficient according to the methods specified in 6.3.1 and 6.3.2.
6.4.2 Test the surface of the slide plate and the front, middle and rear positions of the
inspection station. For equipment in use, test the commonly used positions and the most
severely worn positions, and take the minimum value as the adhesion coefficient test
result.
6.5 Roller reaction brake test bench front and rear ground adhesion coefficient
6.5.1 Test the adhesion coefficient according to the methods specified in 6.3.1 and 6.3.2.
6.5.2 Test the front, middle and rear positions of the ground in front of and behind the
workstation. For the workstations in use, the commonly used positions and the positions
with the most severe wear shall be tested, and the minimum value shall be taken as the
adhesion coefficient test result.
6.6 Service brake road test lane adhesion coefficient
6.6.1 Test the adhesion coefficient according to the methods specified in 6.3.1 and 6.3.2.
6.6.2 Divide the road test lane into left and right sides; test the front, front-center, center,
center-rear and rear positions. For the road test lane in use, the commonly used positions
and the most severely worn positions shall be tested, and the minimum value is taken
as the adhesion coefficient test result.
6.7 Traction parking brake inspection station road surface adhesion coefficient
6.7.1 Test the adhesion coefficient according to the methods specified in 6.3.1 and 6.3.2.
6.7.2 Divide the road surface of the inspection station into left and right sides, and test
the front, middle and rear positions. For the working stations in use, the commonly used
positions and the most severely worn positions shall be tested, and the minimum value
shall be taken as the adhesion coefficient test result.
6.8 Parking ramp surface adhesion coefficient
6.8.1 Place the rubber layer and counterweight of the traction adhesion coefficient test
device on the surface of the ramp to be tested. Slowly apply a tensile force (F) parallel
to the longitudinal geometric center line of the ramp surface to the tensile force sensor
along the parking brake force test direction (see Figure 3) to measure the adhesion force
of the rubber layer and the counterweight from static to relative slippage.
Description of indexing numbers:
1 – counterweight;
2 – rubber layer;
3 – tension sensor;
......
Source: Above contents are excerpted from the full-copy PDF -- translated/reviewed by: www.ChineseStandard.net / Wayne Zheng et al.
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