QC/T 237-1997 in English

1 Scope
This standard specifies bench test items and test methods for automobile parking brake.
This standard is applicable to bench test for automobile parking brake.
This standard is not applicable to the test for parking brake of Semi-trailer.
2 Normative References
The following standards contain provisions which, through reference in this text, constitute provisions of this standard. When this standard is published, the indicated editions are valid. All standards will be revised, and each party in application of this standard shall explore the possiblity of applying the latest versions of the following standards.
JB 393-86 Temperature Measurement and Thermocouple Attachment of Automotive Brake
3 Definitions
The following definitions are adopted in this standard.
3.1 Static Efficiency Test
It refers to the brake test carried out when the installed axle of brake drum (disc) is in steady rotation in the speed ≤ 40r/min.
3.2 Braking Efficiency Test
It refers to the test of braking from one specified rotating speed to another.
3.3 Initial Temperature of Braking
It refers to the temperature of friction lining (pad) of parking brake in starting the brake or that of brake drum (disc).
3.4 Input Point of Braking
It refers to the joint of the force mechanism on the test bench of parking brake with the operating mechanism.
3.5 Input Quantity of Braking
It refers to the acting force at the input point of braking in the same operation direction onboard.
3.6 Transmission Ratio of Parking brake System
It refers to the transmission ratio from operating point of wheelsman to input point of braking in parking brake system.
3.7 Transmission Efficiency of Parking brake System
It refers to the mechanical efficiency from operating point of wheelsman to input point of braking in parking brake system. Its value adopts the design value.
3.8 Classification of Parking brake
3.8.1 Category A Brake
It refers to the brake installed in wheel drag and using the same friction lining (pad) with running brake.
3.8.2 Category B Brake
It refers to the brake with special friction lining (pad) installed in wheel drag.
3.8.3 Center Brake
It refers to the brake installed in the output shaft or driving shaft of the transmission.
4 Test Equipments and Instruments:
4.1 Test Equipment
4.1.1 Test bench of inertia brake shall be used for test and its performance indicator shall meet each item of test requirement.
4.1.2 Braking input device of test bench shall meet the braking input requirements in various test conditions and shall remain steady.
4.1.3 The cooling device of test bench shall make the air velocity at the tested parking brake meet the test requirements.
4.2 Requirements of Instrument and Precision
4.2.1 The accuracy grade of the instrument indicating and recording various parameters shall be not lower than 1.5 Level.
4.2.2 Measurement and control error of input quantity of braking and braking temperature is ±3%; shaft speed error of test bench is ±2%; test rotation inertia (including the inertia of rotating part on test bench) error is ±5%.

Contents
1 Scope
2 Normative References
3 Definitions
3.1 Static Efficiency Test
3.2 Braking Efficiency Test
3.3 Initial Temperature of Braking
3.4 Input Point of Braking
3.5 Input Quantity of Braking
3.6 Transmission Ratio of Parking brake System
3.7 Transmission Efficiency of Parking brake System
3.8 Classification of Parking brake
4 Test Equipments and Instruments:
4.1 Test Equipment
4.2 Requirements of Instrument and Precision
5 Test Conditions
6 Test Methods
6.1 Test Preparation
6.2 Test Item and Test Procedure
Annex A (Normative) Record Format of Test Results
Annex B (Normative) Drafting Format of Trial Curve