Baoli F Series, Руководство по эксплуатации и обслуживанию

Страница: 57 / 102

51
4. Brake system
Type of brake system
Front two-wheel braking, internal expansion,
hydraulic type
Pedal ratio 5.66
Master cylinder bore 19.05mm
Wheel brake 2t, 2.5t 3t, 3.5t
Type Duo-servo type with parking brake
Operating cylinder bore 28.58mm
Size, friction pieces
(L×W×T) 324×60×7mm 348×76×8mm
Area, friction pieces 194.4cm
2
×4
264cm
2
×4
Inner diameter of brake drum 310mm 314mm
Parking brake
Front two-wheel braking, internal expansion,
hydraulic type
4.1 General description
The brake system is the front two-wheel braking type consisting of a master cylinder,
wheel brakes and brake pedal mechanism.
4.2 Master cylinder
The cylinder contains valve seat, check valve, return spring, primary cup, piston and
secondary cup, which are all kept in place with a stop washer and a stop wire. The
exterior of the cylinder is protected from dust by means of a rubber dust cover. The piston
is actuated through the push rod by operation of the brake pedal. As the brake pedal is
pressed, the push rod pushes the piston downward. The brake fluid in the cylinder flows
back to the reserve tank through the return port until primary cup blocks up the return port.
After the primary cup passes through the return port, the brake fluid in the lower cavity of
the cylinder is pressurized and opens the check valve, flowing through the brake pipeline
to the operating cylinder. Thus, each operating cylinder piston is forced outwards. This
brings the friction pieces on the brake shoes come into contact with the brake drum and
slows or stops the truck. Meanwhile, the cavity behind the piston is filled with brake fluid
led through the return port and inlet port. When the brake pedal is released, the piston is
forced back by the return spring. At the same time, the brake fluid in each operating