1. Brake sub-pump is an indispensable part of the brake system chassis brake, its main role is to push the brake pad, brake pad friction brake drum. Make the car speed down and stationary. When the brake is pressed, the main pump produces thrust to press the hydraulic oil into the sub-pump, and the piston inside the sub-pump is moved by the hydraulic pressure to push the brake pad.

2.The air pump is driven by the engine to compress the air to the high pressure gas and store it in the storage tank. One of the cylinders can be connected to the brake master cylinder through the pipeline. The brake master pump is divided into two upper and lower chambers, the upper chamber controls the rear wheels, and the lower chamber controls the front wheels. When the driver stepped on the brake pedal, the upper air was first opened, and the high-pressure gas of the air storage cylinder was transmitted to the relay valve, pushing the control piston of the relay valve out. At this time, the gas of the other air storage cylinder could be connected through the relay valve and two rear brake sub-pumps. The push rod of the brake sub-pump pushes forward and rotates the cam at an angle by adjusting the back. The cam is eccentric. When it rotates, the shoe of the brake is propped apart from the drum to produce friction to reach the brake effect.