Patent ID: 6561075
Filing Date: 2003-05-13
Classification: B60T

Abstract:
A power booster for a brake system, the power booster comprising:a housing having an interior, a diaphragm separating the interior of the housing into at least two chambers, a power piston coupled for movement with the diaphragm and including an output member, a reaction member coupled to the power piston, an input member adapted to be coupled to a movable brake pedal, an air valve assembly movable between open and closed positions to selectively admit atmospheric air into at least one of the chambers to induce an output force on the diaphragm that is transferred to the output member of the power piston, the air valve assembly being length adjustable between the input member and the reaction member and having a portion adapted to engage the reaction member in response to an input force applied to the input member, wherein the air valve assembly operates at a first length when the input force is applied to the input member at a first rate and the air valve assembly operates at a second length shorter than the first length as a result of the input force being applied to the input member at a second, higher rate thereby lowering the input force needed to maintain a desired output force.