US Patent 10139004 Solenoid valve

A solenoid valve includes a housing having a valve passage; a spool configured to switch between an open and closed state of the valve passage; a coil part configured to generate magnetic force when electric current flows therethrough; a yoke surrounding the coil part; a fluid passage provided on an outer side of the coil part, through which the working fluid passes; an introduction passage communicating with the fluid passage to guide the working fluid inside the housing to the fluid passage; and a discharge passage communicating with the fluid passage to discharge the working fluid passed through the fluid passage outside the yoke.