1. The action of the vacuum booster principle
(a) Operation
When braking, the brake pedal is depressed, the pedal force is amplified by the lever action of the control valve putting on. First, the control valve tappet return spring is compressed, the control valve tappet, together with the air valve stem forward. When the control valve before the control position of the valve tappet when the cup is moved into contact with the vacuum valve seat of the vacuum valve port is closed. At this time, the vacuum booster, the gas chamber is separated from the application, the end portion of the air valve stem just contact with the surface of the reaction disk. As the control valve plunger continues forward, the air inlet valve will open. After filtered outside air by opening the air passage leading to the air port and the plenum application, application into the plenum booster (right air chamber), the servo force.
Since the reaction plate material (rubber) have equal force throughout the surface pressure per unit physical property requirements, such as the force of the servo control valve tappet input force is gradually increased from a fixed ratio (Servo libido) growth. Because of the limited resources of the servo power, when the maximum force of the servo, degree of vacuum that is applied plenum zero (i.e., a standard atmospheric pressure), a servo power will be constant, no longer changes.
At this time, the input force and output force of the booster equal increase; canceled braking input force decreases, the control valve is shifted tappet. When the maximum power point, the vacuum valve port is opened, the vacuum booster, the air chamber in communication applications, application of the vacuum chamber will drop, the servo force is reduced, the shift of the piston body. Thus gradually decreases as the input force, the servo force is reduced will become the fixed ratio (ratio servo force) until the brake is completely released.
(ii) non-operating state
in a non-operational state, the control valve tappet return spring pushes the control valve to the push rod locking position the locking tab to the right, the vacuum valve port is open state, the control of the control valve spring cup in close contact with the air valve seat, thus closing the air valve port.
At this time, the booster chamber and the application of vacuum air through each plenumTrue air passage through the chamber and the piston body through the application of the control valve passage gas chamber at a chamber in communication, and isolation from the outside atmosphere. After the engine is started, the degree of vacuum (negative pressure of the engine) at the intake manifold of the engine will rise to -0.0667MPA (i.e. pressure value 0.0333MPA, the pressure difference between atmospheric pressure of 0.0667MPA). Following this, vacuum, application of the vacuum chamber of the booster are raised to -0.0667MPA, and in a ready state ready to work.