Vacuum booster structure and principle

- May 26, 2018 -

The vacuum booster is an important component of the braking system. The performance of the vacuum booster and the damage of the components directly affect the safety of the vehicle. Therefore, the performance and fault of the vacuum booster should be detected in a timely manner, and the vacuum booster for inspection or replacement should be reasonably adjusted. In order to facilitate the inspection and adjustment methods, it is necessary to understand the structure and principle of the vacuum booster.

 Vacuum booster structure and principle

Mainly by the piston, diaphragm, return spring, push rod and joystick, check valve, air valve and plunger (vacuum valve) and other components, its type is a single diaphragm vacuum suspension type. The vacuum booster is installed between the brake pedal push rod and the master cylinder. Its role is to provide assistance for vehicle braking. When not braking, the diaphragm in the booster is suspended in vacuum, and it is balanced by the vacuum of the A and B chambers and the return spring. When the driver steps on the brake pedal, the brake pedal lever pushes the plunger to the left,

At the same time, the air valve also moves to the left under the spring thrust force, so that the channels of the diaphragms A and B are closed and the air valve is opened. At this point, the left side of the diaphragm A cavity is still vacuum, B diaphragm on the right side of the atmosphere, the pressure difference between the two sides of the diaphragm, forcing the diaphragm piston left, and through the push rod to increase the force on On the brake master cylinder piston, this helps the driver. When the brake is released, the brake pedal force disappears, the return spring pushes the diaphragm back to the equilibrium position, and the joystick moves to the right. At this moment, the air valve closes, the vacuum valve opens, and the channels of the A and B chambers communicate with each other. With the same degree of vacuum.