Valve for controlling fluids

A valve for controlling fluids, comprising an actuator unit (4), in particular a piezoelectric unit, for actuating a valve member (3), which is axially displaceable in a valve body and with which a valve closing member (12) is associated, which valve closing member cooperates with at least one valve seat (14, 15) for opening and closing the valve (1) and separates a low-pressure region (16) at system pressure from a high-pressure region (17), the valve member (3) having at least one first piston (9) and one second piston (11) between which a hydraulic chamber (13) functioning as a hydraulic booster is embodied, and a filling device (24) connectable to the high-pressure region (17) to compensate for leakage losses, the filling device (24) being embodied with at least one channel-like hollow chamber (25), in which at least one throttle body (26) is disposed in such a way that on one end of the throttle body (26), a line (33) leading to the high-pressure region (17) discharges into the hollow chamber, and that on the opposite end of the throttle body (26), a system pressure line (28) leading to the hydraulic chamber (13) branches off, and by geometric definition of the throttle body (26), embodied as a solid body, of a gap (27) surrounding it, and of the dimensions of the piston (9) along which the system pressure (p_sys) is reduced toward the low-pressure region (16), a system pressure (p_sys) builds up in the high-pressure region (17) as a function of a prevailing pressure (p_R).