GB/T 44411-2024Testing methods for the adhesion coefficient of motor vehicle inspection equipment and sites (English PDF)

5.2 Test device for tractor 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

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.

6.1 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 Free roller surface adhesion coefficient...

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

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 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.

6.5.1 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.

6.6.1 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.

6.7.1 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.