ACTUATOR FOR ANTI-LOCK DEVICE OF VEHICLE

PURPOSE:To improve pedal feeling by forming an auxiliary cylinder normally communicated with a reservoir in a master cylinder, and feeding pressure liquid from the liquid chamber of the auxiliary cylinder into the pressure chamber of the master cylinder when anti-skid control is carried out. CONSTITUTION:Control valves 21-23 integrally assembled with a supply switching valve and a discharge switching valve are fixed in a lower space of the body 11a of a brake master cylinder 11 and energized/de-energized repeatedly through an electrical controller 30 corresponding to wheel lock condition so as to carry out anti-skid control. An auxiliary cylinder 25 is formed in the master cylinder 11 and the liquid chamber 25a thereof is communicated through a path Pdelta with a reservoir 11c, while a two-port two-position solenoid valve, i.e. a normal open cut valve 24, is arranged in the way of the path Pdelta. The normal open cut valve 24 closes during anti-skid control thus enabling supply of pressure liquid from the liquid chamber 25a through a piston cup 11f into a pressure chamber 11d.