Patent ID: 8707994

Claim:
A solenoid valve comprising: a linear solenoid; a common cylindrical sleeve, one axial end of which is fixed to the linear solenoid; a common spool movably accommodated in the sleeve and moved in its axial direction by an operation of the linear solenoid when electric power is supplied thereto; a return spring provided in the sleeve between the other axial end thereof and the spool for biasing the spool in a direction to the one axial end of the sleeve; a first three-way valve formed by a first portion of the sleeve and a first portion of the spool for operating as a normally-closed type valve; and a second three-way valve formed by a second portion of the sleeve and a second portion of the spool for operating as a normally-opened type valve, wherein the first three-way valve comprises: a first feedback land, a first input-port controlling land and a discharge-port controlling land, each of which is formed in the first portion of the spool and arranged in this order from a spring-side end of the spool toward a middle portion thereof, wherein the first feedback land and the first input-port controlling land are connected to each other by a small-diameter portion of the first portion of the spool; and a first feedback port, a first input port, a first output port and a discharge port, each of which is formed in the first portion of the sleeve and arranged in this order from the other axial end of the sleeve toward a middle portion thereof; and wherein the second three-way valve comprises: a discharge-port controlling land, a second input-port controlling land and a second feedback land, each of which is formed in the second portion of the spool and arranged in this order from the middle portion of the spool toward a solenoid-side end of the spool, wherein the second input-port controlling land and the second feedback land are connected to each other by a small-diameter portion of the second portion of the spool; and a discharge port, a second output port, a second input port and a second feedback port, each of which is formed in the second portion of the sleeve and arranged in this order from the middle portion of the sleeve toward the one axial end thereof, wherein the discharge-port controlling land of the first three-way valve and the discharge-port controlling land of the second three-way valve are formed as one common land, and wherein the discharge port of the first three-way valve and the discharge port of the second three-way valve are formed as one common port.