Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative.
This standard is developed in accordance with the rules given in GB/T 1.1-2009.
This standard was proposed by and is under the jurisdiction of SAC/TC 364 National Technical Committee on Operating Safe Technology and Testing Equipment for Motor Vehicles of Standardization Administration of China.
Parking brake performance test methods for vehicles
1 Scope
This standard specifies the parking brake performance test methods for vehicles.
This standard is applicable to all kinds of vehicles and combination vehicles travelling on the roads in China.
2 Normative references
The following referenced documents are indispensable for the application 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 7258 Technical specifications for safety of power-driven vehicles operating on roads
GB/T 13564 Roller opposite forces type automobile brake tester
GB 21861 Items and methods of motor vehicles safety technology inspection
GB/T 28529 Platform brake tester
GB/T 28948 Commercial vehicle - Front towing attachments
GB 32087 Towing devices for light-duty vehicle
3 Terms and definitions
For the purposes of this document, the terms and definitions given in GB 7258 and GB 21861 as well as the following apply.
3.1
parking brake performance
capability of vehicles parking on ramps
3.2
parking ramp
ramp used to test the parking brake performance of vehicles
3.3
the slope of parking ramp
ratio of the vertical height to the horizontal length of the parking ramp, in %
?
3.4
parking brake performance tester
instrument or measuring device that measures the braking force of vehicles in the parking brake state and evaluates the parking brake performance in combination with the complete vehicle mass, and measures the braking force of vehicles in the parking brake by force sensor
4 Inspection conditions
4.1 The kerb mass of the vehicle under test shall meet the requirements of GB 7258 and GB 21861.
4.2 The operation state of the vehicle under test shall meet the requirements of GB 7258 and GB 21861.
4.3 The tires of the vehicle under test shall be dry and clean, free from mud, water and oil stain.
4.4 The traction device of the vehicle under test shall meet the requirements of GB/T 28948 and GB 32087 in the application of traction method.
5 Test methods
5.1 Ramp test method
5.1.1 Facilities requirements
5.1.1.1 There shall be one parking ramp with gradient of 15% and 20% respectively. The length of the ramp shall be 1m longer than the maximum wheelbase of vehicle under test, and shall be 1m wider than the maximum width of vehicle under test. The ramp adhesion coefficient shall not be less than 0.7.
5.1.1.2 The electronic stopwatch or mechanical stopwatch with resolution of 0.01s.
5.1.2 Test method
5.1.2.1 Drive the vehicle under test straightly and smoothly into the parking ramp with a gradient of 20% (15% for vehicles whose total mass is less than 1.2 times of the kerb mass), stop the vehicle with the service brake and put the transmission in neutral state.
5.1.2.2 Operate the parking brake control device according to the following requirements:
a) applied force: when operating by hand, the force applied to the passenger car shall be less than or equal to 400N, and that to other motor vehicle shall be less than or equal to 600N; when operating by feet, the force applied to passenger cars shall be less than or equal to 500N, and that to other motor vehicles shall be less than or equal to 700N;
b) operating stroke: more than two-thirds of the total stroke, and more than three-quarters of the total stroke for the parking brake mechanism equipped with automatic adjustment device.
5.1.2.3 Release the service brake control, and after confirming that the vehicle under test has completely stopped, observe continuously for 5min, and the vehicle shall remain still.
5.2 Roller opposite forces type brake tester method
5.2.1 Facilities requirements
The roller opposite forces type brake tester shall meet the requirements of GB/T 13564.
5.2.2 Test method
5.2.2.1 The vehicle under test travels in an upright and centered manner, park each axle on the axle (wheel) load meter in turn for the specified time (not less than 3s), and measure the static wheel loads respectively.
5.2.2.2 The vehicle under test travels in an upright and centered manner, park the wheels under test on the drum, the transmission is in neutral state, release the brake pedal; for full-time four-wheel drive vehicles, put the wheels not under test on the auxiliary free roller set with adhesion coefficient meeting the requirements, and the transmission is in neutral state.
5.2.2.3 Start the drum motor and stabilizes it for 3s, operate the parking brake control device for the parking brake axle in accordance with 5.1.2.2, and measure the parking brake force value.
5.2.2.4 The parking brake ratio is the percentage of the sum of the measured braking forces of each parking brake forces and the sum of the (static) axle loads of all axles of the vehicle.
5.3 Platform brake tester method
5.3.1 Facilities requirements
The platform brake tester shall meet the requirements of GB/T 28529.
5.3.2 Test method
5.3.2.1 The vehicle under test slides at the speed of 5km/h~10km/h, and after the transmission is in neutral state (for automatic transmission vehicles, the transmission may be in "D" gear), it drives on the platform in a straight and smooth manner.
5.3.2.2 When the parking brake axles of the vehicle are all drive onto the platform, operate the parking brake control device for the parking brake axle in accordance with 5.1.2.2, and measure the parking brake force value.
5.3.2.3 When all wheels under test drive on the platform, keep the vehicle still and measure the static wheel load of each wheel.
5.3.2.4 The parking brake ratio is the percentage of the sum of the measured braking forces of each parking brake forces and the sum of the (static) axle loads of all axles of the vehicle.
5.4 Traction test method
5.4.1 Facilities requirements
5.4.1.1 The measuring range of traction parking brake performance tester is generally not less than 7,000daN (or meet the requirements of the instruction).
5.4.1.2 The inspection area shall be a flat, hard and clean cement or asphalt pavement, and the road adhesion coefficient shall not be less than 0.7.
5.4.1.3 Traction devices at the front and rear of vehicles and their fasteners shall not be damaged, invalid, broken or deformed to affect normal use.
Foreword II
1 Scope
2 Normative references
3 Terms and definitions
4 Inspection conditions
5 Test methods
Bibliography
