Golden Dragon XML6125CLE, Repair Manual

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BR-10 Brake System BR-6125J93C-01
图形符号
Graphical symbol
梭阀工作原理图
Schematic diagram of a shuttle valve
a) Air intake of control port P1
b) Air intake of control port P2
4. Brake air chamber
The air brake chamber is used to convert the air pressure energy into mechanical energy and to output the
mechanical energy to the actuating device, making the brake to produce a brake torque.
In service braking, the air brake valve will open the passage to the relay valve. The compressed air from the right
rear air reservoir flows via the relay valve, ABS solenoid valve, and the port 11 into the cavity A and functions on the
diaphragm d, which will compress the spring c to propel the piston e and functions on the brake via the pushrod b,
applying a brake torque on the wheels.
In parking braking or auxiliary braking, the hand brake valve will force the compressed air in the cavity B to be
fully or partially released via the port 12 and the quick release valve. The spring f will also fully or partially release its
energy to produce a brake torque on the wheels via the piston e, pushrod b and the brake arm.
Screwing out the bolt g will release the parking brake mechanical devices, which is used to release the brake
manually in case of no compressed air.
5.
Device for braking force adjustment—ABS
Considering from improving the safety of car braking, the adhesion conditions should be fully utilized to produce
a possibly largest braking force and it is better to realize a simultaneous lock and slip of both front and rear wheels.
Once the wheels are locked up, the braking efficiency will deteriorate and the car may lose the steering capability (if
the front wheels are locked up) or the driving stability (if the rear wheels are locked up). ABS (anti-lock braking system)
is the best means to improve the braking performance..
‹ Outline of principle
The car wheel motion can be classified into three states: pure rolling,
rolling while slipping and full drag-slipping. Slip rate S is generally used
to characterize the slipping proportion in the wheel longitudinal motion.
The change in the longitudinal and lateral adhesion coefficients between
wheels and the ground with that of the slip rate S are closely related to the
wheel motion conditions.
1) When the wheels make a pure rolling, the longitudinal adhesion
coefficient
φ Z will be zero;
2) When the slip rate S is 10%~20%, the longitudinal adhesion
8-10