| 摘要 |
PROBLEM TO BE SOLVED: To provide a brake system for a vehicle, which can suppress delay of a rise of brake fluid pressure, and an electric actuator.SOLUTION: A motor cylinder device comprises a ball screw structure which rectilinearly moves a ball screw shaft 205a by rotation drive force of an electric motor, and a slave piston which generates brake fluid pressure while being displaced accompanied with the rectilinear movement of the ball screw shaft 205a. Then, the ball screw structure rectilinearly moves the ball screw shaft 205a by rolling balls which are arranged at an inner peripheral side of a ball screw nut 205b which is externally fit to the ball screw shaft 205a by the rotation of the ball screw nut 205b, and a slit 251 which is engaged with a guide pin 252 of the ball screw shaft 205a, and guides the rectilinear movement of the ball screw shaft 205a is formed so as to rotate the ball screw shaft 205a performing the rectilinear movement, around a center line CL. |
