Patent ID: 8006718

Claim:
An electric spool valve comprising: a sleeve having an input port, an output port, and only one discharge port, the sleeve having an inner periphery defining an insertion hole; a spool axially slidable along the inner periphery of the sleeve to control communication among the input port, the output port, and the discharge port; and an electric actuator provided to one end of the sleeve to axially exert driving force to the spool, wherein the spool has an axial through hole, which axially extends through the spool, the spool has one end defining a spool breathing hole, the electric actuator has at least one variable volume chamber, which communicates with the discharge port of the sleeve through the axial through hole and the spool breathing hole of the spool, and the spool has a communication through hole configured to lead fluid from the output port of the sleeve to the discharge port of the sleeve through the axial through hole of the spool, the electric spool valve further comprising: a passage partition member provided in the axial through hole to partition the axial through hole and define an in-spool breathing passage, which communicates with the spool breathing hole.