Electromagnetic valve for a hydraulic brake

An electromagnetic valve for brake fluid pressure control having an inlet and an outlet, comprising:

• a first communication path connecting the inlet and the outlet for brake fluid flow;
• a first valve seat provided within the first communication path;
• a second communication path connecting the inlet and the outlet for brake fluid flow in parallel to the first communication path, one of the first and second communication paths having a throttle portion for partly restricting brake fluid flow;
• a second valve seat provided within the second communication path;
• a first plunger member being provided with a first valve being movable so as to come in contact with the first valve seat for closing and opening the first communication path, and further provided with a penetration hole constituting a part of the second communication path;
• a second plunger member being provided with a second valve being movable in the penetration hole so as to come in contact with the second valve seat for closing and opening the second communication path, wherein the first and second plunger members are arranged axially in series with a gap therebetween;
• a spring member disposed at least between the first and second plunger members for generating a spring biasing force against the first and second plunger members in a direction that the first and second plunger members move axially away from each other;
• and
• a coil member arranged around outer circumferences of the first and second plunger members for generating an electromagnetic attracting force, when energized, to move the first and second plunger members against the spring biasing force in a direction that the first and second plunger members come close to each other so that the first valve is moved from an upstream side of brake fluid flow to a downstream side thereof and the second valve is moved from the downstream side thereof to the upstream side thereof, the first and second plunger members being at rest positions at an original stage that the coil member is not energized, being driven to come closer to each other at an initial stage that the coil member is initially energized, and being further driven to come closest to each other at a final stage that the coil member is fully energized;
• wherein the electromagnetic valve is controlled in any one of three operating states representing a fully-open state that both the first and second communication paths are open, and the coil member is at one stage of the original and final stages, a half-open state that the one of the first and second communication paths having the throttle portion is opened and the other one of the first and second communication paths is closed, and the coil member is at the initial stage, and a fully-closed state that both the first and second communication paths are closed, and the coil member is at the other stage of the original and final stages.