Patent ID: 6164183
Filing Date: 2000-12-26
Classification: B60T

Abstract:
In a brake booster comprising:a differential pressure actuator having a working chamber and an output member;a power piston fixed to the output member and having a low pressure valve seat;an input member within the power piston, axially movable with respect thereto and carrying a translating valve member having a working pressure valve seat;a control valve member axially movable with respect to, biased toward, and engageable with both the low pressure valve seat and the working pressure valve seat so that at least one of the low pressure valve seat and the working pressure valve seat is engaged with the control valve member at all times, the control valve member opening the working chamber to a low pressure fluid passage for deactivation of the differential pressure actuator when disengaged from the low pressure valve seat and opening the working chamber to a working pressure fluid passage for activation of the differential pressure actuator when disengaged from the working pressure valve seat, the input member being moved with braking input in an axial direction to disengage the control valve member from the working pressure valve seat and thus actuate the differential pressure actuator and the power piston being moved by the output member with activation of the differential pressure actuator in an axial direction to move a booster output rod with a boosted force and to disengage the low pressure valve seat from the control member;the improvement comprising:a rotary electric motor within the brake booster, the rotary electric motor being carried on the input member and having an axial output shaft;the translating valve member being axially movable with respect to the input member; androtary to linear motion conversion apparatus linking the output shaft of the rotary electric motor to the translating valve member so that rotary motion of the output shaft produces linear axial motion of the translating valve members relative to the input member, when the rotary electric motor is activated.