Solenoid valve for brake system

1. A solenoid valve for a brake system comprising:

a filter member accommodated in a bore of a modulator block including an inlet path and a discharge path;

a magnet core coupled to the filter member and including a through hole longitudinally passing through the magnet core;

a sleeve coupled to an outer surface of the magnet core;

an armature installed in the sleeve;

a valve seat fixed to the through hole and including an orifice;

a plunger disposed at the through hole to open and close the orifice while vertically being moved by movement of the armature; and

a returning spring configured to press the plunger against the armature,

wherein a boss inserted into the valve seat through an opening of a lower end of the filter member and including a connecting path configured to cause the orifice to communicate with the discharge path is formed to pass through a center of the filter member, a plunger valve vertically, moved due to a pressure of supplied oil and including a vertical hole formed to pass through a center of the plunger valve is disposed below the connecting path, and a plunger valve seat having a diameter greater than that of a diameter of the connecting path is provided at a lower end of the connecting path to selectively come into contact with an outer surface of the plunger valve when the plunger valve vertically moves.

2. The solenoid valve of claim 1 , wherein a width of the plunger valve seat gradually increases in a downward direction.

3. The solenoid valve of claim 1 , wherein the plunger valve seat has a size to accommodate the plunger valve and a corn shape including a horizontal surface horizontally extending from a lower end of the connecting path and an inclined surface inclined downward from an edge of the horizontal surface.

4. The solenoid valve of claim 3 , wherein the plunger valve includes a sealing portion configured to come into contact with the inclined surface when the plunger valve is moved upward due to the pressure of the supplied oil.

5. The solenoid valve of claim 3 , wherein, when the plunger valve is moved downward and separated from the plunger valve seat, the oil is allowed to flow through the vertical hole and a gap between the plunger valve and the plunger valve seat.

6. The solenoid valve of claim 3 , wherein, when the plunger valve is moved upward and comes into contact with the plunger valve seat, the oil is allowed to flow through only the vertical hole.

7. The solenoid valve of claim 1 , wherein:

the filter member covers an outer surface of a lower side of the magnet core; and

the outer surface includes a circumference coupled to the bore.

8. The solenoid valve of claim 7 , wherein:

a first filter configured to filter oil introduced into a flow path formed between the filter member and a lower end of the magnet core through the inlet path is provided at the circumference of the filter member; and

a second filter configured to filter oil discharged toward the discharge path is provided at the lower end of the filter member.

9. The solenoid valve of claim 1 , wherein the vertical hole causes the connecting path to continuously communicate with the discharge path.

10. The solenoid valve of claim 3 , wherein the plunger valve is formed with a sealing portion formed in a hemisphere shape and configured to come into contact with the inclined surface when the plunger valve is moved upward due to the pressure of the oil, and a cylinder located below the sealing portion, and has a cross section having an arch shape.