Brake valve is the main control device of automobile service brake system. The brake valve is mainly composed of upper chamber piston, lower chamber piston, push rod, roller, balance spring,
return spring (upper and lower chamber), upper chamber valve, lower chamber valve, air inlet, air outlet, exhaust port and vent hole
When the driver steps on the pedal, by stretching the lever to pull arm one end of the pressure balance spring, the balance arm moves down, first the exhaust valve is closed, open the intake valve,
the compressed air of the air storage cylinder through the intake valve into the brake chamber, push the diaphragm of the chamber brake CAM rotation so as to achieve wheel braking.