Patent ID: 6082241
Filing Date: 2000-07-04
Classification: B60T

Abstract:
An automatic brake booster including a valve body slidably disposed within a shell, a power piston mounted on the valve body, a constant and a variable pressure chamber defined across the power piston, a valve mechanism disposed within the valve body, an input shaft associated with the valve mechanism for switching a flow path in the valve mechanism, wherein the valve mechanism includes a vacuum valve seat formed on the valve body, a plunger slidably mounted on the valve body, an atmosphere valve seat formed on the valve plunger and a valve element urged from the rear side to be seated upon the vacuum valve seat and the atmosphere valve seat, further including a solenoid which drives the plunger forward to switch the flow path in the valve mechanism, independently from the input shaft;characterized by a piston mounted on the plunger and which is subject to the atmospheric pressure and a pressure which prevails in the constant pressure chamber to urge the plunger rearward.