Solenoid valve for brake systems

A solenoid valve for brake systems having a hollow valve housing provided on an outer circumferential surface thereof with a fluid inlet and provided on one end of the valve housing with a fluid outlet, and an armature provided with a plunger extending into a bore of the valve housing in such a way as to selectively open a fluid passage from the inlet to the outlet while moving by electric power, said solenoid valve comprising:

• a spool movably set in said valve housing;
• a first orifice having a predetermined diameter provided along a central axis of the spool;
• a plunger guide inside the spool and provided at a position around the plunger, wherein the plunger guide has a predetermined depth for allowing the plunger to enter the spool and open or close the first orifice;
• a valve seat portion formed on an inner surface of the bore of the valve housing by stepping said surface, said valve seat portion defining a second orifice therein and coming into contact with or being spaced from an end of said spool to selectively close or open said outlet separately from the first orifice, said second orifice having an inner diameter larger than that of the first orifice;
• and
• a spool restoring spring biasing the spool toward the plunger.