51
51
4.1 General
4.1 General description
description
The brake system is the f
The brake system is the front two-wheel braking type consisting of
ront two-wheel braking type consisting of a master cylinder,
a master cylinder,
wheel brakes and brake
wheel brakes and brake pedal mechanism.
pedal mechanism.
4.2 Master cylinder
4.2 Master cylinder
The cylinder contains valve seat, check valve, return spring, primary cup, piston and
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
secondary cup, which are all kept in place with a stop washer and a stop wire. The
exterior of the
exterior of the cylinder is protected from dust
cylinder is protected from dust by means of a rubber
by means of a rubber dust cover
dust cover. The piston
. The piston
is actuated through the push rod by operation of the brake pedal. As the brake pedal is
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
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
back to the reserve tank through the return port until primary cup blocks up the return port.
return port.
After the primary cup passes through the return port, the brake fl
After the primary cup passes through the return port, the brake fluid in the l
uid in the lower cavity of
ower cavity of
the cylinder is pressurized and opens the
the cylinder is pressurized and opens the check valve, flowing through the brake
check valve, flowing through the brake pipeline
pipeline
to the operating cylinder. Thus, each operating cylinder piston is forced outwards. This
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
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
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
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
forced back by the return spring. At the same time, the brake fluid in each operating
cylinder is pressurized by the return spring,
cylinder is pressurized by the return spring, returning into the master cylinder through the
returning into the master cylinder through the
check valve. With the piston in its original position, the brake fluid in the master cylinder
check valve. With the piston in its original position, the brake fluid in the master cylinder
flows into the reserve tank through the return port. The brake fluid in the brake pipelines
flows into the reserve tank through the return port. The brake fluid in the brake pipelines
and operating master has a residual pressure proportioned to the set pressure of the
and operating master has a residual pressure proportioned to the set pressure of the
check valve, which makes each operating cylinder piston cup securely seated to prevent
check valve, which makes each operating cylinder piston cup securely seated to prevent
oil leakage and eliminates a possibility of air locking when the
oil leakage and eliminates a possibility of air locking when the truck is sharply braked. See
truck is sharply braked. See
Fig4.1.
Fig4.1.
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