14
4.3.1 Service brake
The service brake is composed of the brake system master cylinder, brake and brake pedal etc., When it is
necessary to brake during the travel of forklift, you can depress the brake pedal, which will drive the brake
master cylinder, and transfer the hydraulic oil to the brake systems in the L/R gearboxes. The brake disc will
brake up the wheel load under the effect of oil pressure. (Fig. 4-7)
Fig.4-7 Service brake
4.3.2 Brake master cylinder
The master cylinder includes a valve seat, a check valve, a return valve and leather cup, piston and auxiliary
leather cup. The end is fixed with the stop washer and locking wire. The external is protected with the rubber
dust cover. The master cylinder piston is controlled by operating the brake pedal through the push rod. When
the brake pedal is depressed, the push rod will push forward the piston and the brake fluid in the pump body
flows back to the oil tank through the return opening until the oil drain hole is banned by the primary cup. After
the primary cup is pushed over the return opening, the brake fluid in the front cavity of master cylinder will be
compressed and open the check valve resulting in flowing toward the slave cylinder through the brake pipeline.
So each position of slave cylinder piston will extend outward making the friction plate of brake shoe get contact
with the brake drum to achieve the effect of speed reduction or brake. Now, the rear cavity of piston is
supplemented by the brake fluid originated from the return opening and oil inlet. After the brake pedal is
released, the piston is pressed by the reset spring, and at the same time, the brake fluid in each brake slave
cylinder is compressed by the return valve of brake shoe, which brings the brake fluid back to the master
cylinder through the check valve (front cavity of piston) and resets the piston. The brake fluid in the master
cylinder flows back to the oil tank through the return opening. Check the valve pressure and adjust it to a
proportion with residual pressure in the brake pipeline and sub-pump of brake, making the leather cup of slave
To Next Page
Loading...
General