Patent ID: 7367187

Claim:
An electrically actuated brake booster including: a first member adapted to move forward and backward in accordance with operation of a brake pedal; a second member disposed so as to be capable of moving relative to the first member; and an electric actuator for moving the second member forward and backward, wherein a hydraulic brake pressure is generated in a master cylinder by an input thrust applied to the first member by the brake pedal and a booster thrust applied to the second member by the electric actuator, such that a part of a reaction force resulting from the hydraulic brake pressure is transmitted to the first member, while another part of the reaction force is transmitted to the second member, the electrically actuated brake booster comprising: urging means disposed between the first member and the second member, wherein, when the first member and the second member are displaced relative to each other in at least one direction, an urging force of the urging means against the first member in a direction in which the second member is displaced relative to the first member becomes larger than that in a state prior to the relative displacement between the first and the second members.