What are the six lines of the brake relay valve?

The six pipelines of the brake relay valve are air inlet pipe, exhaust pipe, pressure pipe, oil inlet pipe, oil return pipe and oil-gas separation pipe. According to relevant public information, the intake pipe and exhaust pipe are used to control the air path of the brake relay valve. When the brake pedal is depressed, the air pressure in the air path will change, thus controlling the opening and closing of the brake relay valve. The pressure pipe is used to transmit the pressure signal of the braking system, and the oil inlet pipe and oil return pipe are used to transmit hydraulic oil. Oil-gas separation pipe is used to separate gas and liquid to ensure the stability of hydraulic oil.