Electrically driven brake booster

摘要

In an electrically driven brake booster wherein an electrically driven actuator moves a booster piston upon operation of a brake pedal to generate a hydraulic pressure for driving a brake force at the maser cylinder, the electrically driven actuator controls to move the booster piston as the pressing member in order to correctly detect presence/absence of an operation of the booster piston and detect a movement pattern of an input rot and an input piston as the shaft member relative to a movement of the pressing member. In accordance with the movement pattern, presence/absence of an operation of the brake pedal is detected. By confirming that the brake pedal is not operated, by the method described above, a zero point of a stroke sensor for detecting the position of the shaft member and zero points of oil pressure sensors for detecting a hydraulic pressure supplied by the master cylinder are learnt.

主权项

1. An electrically driven brake booster comprising:
a master cylinder for generating a hydraulic pressure to be used for generating a brake force; a pressing member for controlling a hydraulic pressure generated by said master cylinder; a shaft member configured to be operated with said pressing member by force operating on a brake pedal to push the brake pedal back toward a release side when the pressing member is not operated, the force changing according to movement of said pressing member; an electrically driven actuator for moving said pressing member forward and backward; a sensor to be used for measuring a movement or a position of said shaft member; and a controller; wherein: said controller is configured to control said electrically driven actuator in accordance with an operation of the brake pedal to control a hydraulic pressure to be generated by said master cylinder; and said controller is configured to perform a learning operation to set a movement reference point for said shaft member, the learning operation comprising:
controlling said actuator to cause a movement of said pressing member,detecting the movement of said shaft member caused by the movement of said pressing member using said sensor,judging the presence/absence of an operation of the brake pedal in accordance with the detected movement of said shaft member so as to determine a state that the brake pedal is not operated, andsetting a position of the shaft member as the movement reference point when it is judged that the pedal is not operated.