BRAKING-FORCE ASSISTOR

A brake booster in a housing, having a servo piston slidably supported in the housing and having a piston rod protruding into the housing for transmitting a brake force. A chamber is provided in the servo piston for receiving brake fluid drawn after the opening of a valve from a reservoir or supply container and pumped via a pump or the like. The chamber also communicates via a further valve or the like with a return line to the supply container. To improve the closing behavior of the valve, the first valve for the admission of the brake fluid is formed in the chamber, embodied as a servo chamber, by a valve bushing, or its annular collar, and a valve seat in a blind bore recess in the servo piston. On the other side, the valve bushing, with a bottom, engages the inside of a bell-shaped valve seat, which together with the piston rod, or a slide connected to the piston rod, forms the valve for returning the brake fluid.