Hydraulic anti-skid apparatus for automotive vehicles

Abstract

A hydraulic anti-skid apparatus for automotive vehicles includes a cut-off valve disposed within a braking circuit connecting a master cylinder to a wheel brake cylinder, a bypass valve disposed within a bypass passage of the braking circuit, first and second pistons respectively arranged to control opening and closing operations of the cut-off valve and the bypass valve, the first and second pistons each being arranged to be applied at one end thereof with a hydraulic braking pressure from the master cylinder and at the other end thereof with a hydraulic power pressure from a fluid pump, a solenoid valve arranged to apply the power pressure to the first piston in its deactivated condition and to connect the first piston to a fluid reservoir in its activated condition, a regulator valve arranged to control the power pressure applied to the first and second pistons in accordance with the braking pressure applied thereto, the regulator valve including a booster piston assembly having a small diameter portion applied with the power pressure and a large diameter portion applied with the braking pressure. The regulator valve acts to cooperate with a check valve in response to movement of the booster piston assembly thereby to produce a hydraulic pressure at a higher value than the braking pressure.