Antiskid control system for vehicle with electromagnetic valve having throttled position

Claim 1

An antiskid control system comprising: a holding pressure valve interposed in a main transmission line connecting a master cylinder and a wheel cylinder of a braking device for holding a hydraulic pressure of said wheel cylinder when it is changed over to a closed position; a pressure reducing valve of a normally closed type interposed at a by-pass transmission line branched out from said main transmission line at a downstream side of said holding pressure valve and releasing the hydraulic pressure of said wheel cylinder to a reservoir when the pressure reducing valve is changed over to an open position; a pressure accumulator being interposed within said by-pass transmission line for accumulating fluid pumped up from said reservoir by a pump; a gate valve of a normally open type interposed at the upstream side of said holding pressure valve within said main transmission line; said by-pass transmission line connecting said accumulator and said gate valve; a pressure increasing valve provided in said by-pass transmission line between said accumulator and said gate valve; said pressure increasing valve having a fluid passage throttling position and a fluid passage opening position; a differential pressure operated piston in said gate valve having one end on which the hydraulic pressure of said accumulator works and the other end on which the hydraulic pressure of said wheel cylinder works, and being shifted by the difference in the hydraulic pressure working on said both ends for shutting off the communication between said master cylinder and said holding pressure valve by closing a valve part of said piston within said gate valve; and said gate valve having a check valve housed within said differential pressure operated piston for allowing a flow of the fluid from said pressure increasing valve towards said holding pressure valve.