Patent attributes
A solenoid valve includes: a sleeve having a supply port and an output port; a spool valve that is housed in a valve hole formed in the sleeve so as to be movable in the axial direction, and that changes a flow passage area between the supply port and the output port by moving in the axial direction; a solenoid portion that pushes the spool valve toward one axial side; and a coil spring that urges the spool valve toward the solenoid portion. A housing hole that is a bottomed hole is formed in the spool valve, and a columnar piston member is slidably housed in the housing hole. The spool valve has an introduction hole through which a pressure of the hydraulic fluid output from the output port is introduced into a space between a bottom face of the housing hole and one end face of the piston member.
