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A hydraulic control device for an anti-skid brake system for a vehicle, including a solenoid-operated directional control valve for communication of a pressure chamber in a hydraulic actuator, selectively with a hydraulic power source and a reservoir, and a solenoid-operated flow control valve dispo

A hydraulic control device for an anti-skid brake system for a vehicle, including a solenoid-operated directional control valve for communication of a pressure chamber in a hydraulic actuator, selectively with a hydraulic power source and a reservoir, and a solenoid-operated flow control valve disposed between the directional control valve and one of the pressure chamber, hydraulic power source and reservoir, the hydraulic control device being operated to effect rapid and slow rise and fall of a pressure in the hydraulic actuator, in response to a slip ratio of a wheel of the vehicle. The flow control valve comprises a flow restrictor which permits a restricted flow of a fluid through the valve even when its valving member is seated on a valve seat in which a valve hole is open. The flow restrictor is provided in one of various forms except an ordinary orifice with a small diameter. The flow restrictor may be a groove formed in an end face of a valving member opposite to the valve seat, a rough or ragged surface of the valve seat or valving member, or a porous structure formed on the valving member so as to contact the valve seat. Alternatively, the flow restrictor may be formed by a porous structure which fills a hole formed in parallel with the valve hole which is open in the valve seat.

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A hydraulic control device for an anti-skid hydraulic brake system for a vehicle having a hydraulic actuator, for effecting rapid rise and fall and slow rise and fall of a pressure in a pressure chamber in said hydraulic actuator, in response to a slip ratio of a wheel of the vehicle, the hydraulic

A hydraulic control device for an anti-skid hydraulic brake system for a vehicle having a hydraulic actuator, for effecting rapid rise and fall and slow rise and fall of a pressure in a pressure chamber in said hydraulic actuator, in response to a slip ratio of a wheel of the vehicle, the hydraulic control device including a solenoid-operated directional control valve for selective connection of said pressure chamber in said hydraulic actuator with a hydraulic power source and a reservoir, and further including a solenoid-operated flow control valve disposed between the directional control valve and one of said pressure chamber, said hydraulic power source and said reservoir, to control a flow of a fluid in two steps, said solenoid-operated flow control valve comprising: means for defining a valve hole; a valve seat in which said valve hole is opened; a valving member movable between a first position in which the valving member is seated on said valve seat, and a second position in which the valving member is spaced apart from said valve seat; and a solenoid which is energized and deenergized for moving said valving member between said first and second positions; wherein one of the contact surfaces of said valving member and said valve seat which contact each other when said valving member is placed in said first position is formed with minute projections which provide gaps between said contact surfaces while said valving member in said first position is seated on said valve seat, thereby serving as a flow restictor for permitting a predetermined rate of restricted flow of the fluid through said valve hole when said valving member is in said first position, said predetermined rate of restricted flow being less than a rate of flow of the fluid when said valving member is in said second position.