Solenoid valve

Claim 1

A solenoid valve comprising a valve housing provided therein with an exciting coil; a valve body formed with a trench at one end thereof, with a through-hole inside thereof and with a plurality of oil introducing holes communicating with said through-hole and opened up at a peripheral surface thereof, said valve housing being secured to said trench; a sleeve secured into said through-hole and formed therein with a valve bore, said sleeve being provided with a plurality of ports for communicating the valve bore and the oil introducing hole and an introducing hole communicating with the bore and trench, said ports and introducing hole being opened up at a peripheral surface of said sleeve; a spool slidably contained within said valve bore and formed therein with a center hole communicating with an oil tank, said spool being provided with a plurality of throughholes opened up at a peripheral surface thereof and communicating with the trench and valve bore, said spool being normally energized towards said valve housing by a spring; a stationary iron core including a shaft barrel portion disposed inside said coil and a flange disposed within said trench, said flange being formed at an end face thereof with a trench, said trench being formed at an inner peripheral surface thereof with an oil groove communicating with said trench; a plunger chamber means having a bottom formed inside said iron core and communicating with the trench of said flange; a tubular plunger guide having a bottom made of a nonmagnetic material and disposed at a home position of an inner peripheral surface of the plunger chamber means; a plunger slidably contained within said plunger guide and driven by electromagnetic force of said coil, said plunger being normally energized towards said valve body by a plunger spring; a stopper including a shaft barrel portion contained within said plunger chamber means and a flange contained within the trench of said flange, an end face of said flange being engaged with an end face of said sleeve, said shaft barrel portion and flange being formed at an peripheral surface and inner peripheral surface thereof with an oil groove communicating with each other, said oil groove being communicated with said plunger chamber means and oil groove, said stopper being formed therein with a passage hole communicating with said plunger chamber means; a diaphragm mounted on an end portion of said spool and adapted to block the communication between the adjacent valve bore and passage hole; and an oil reservoir chamber means defined by the inner peripheral surface of the trench, the peripheral surface of the spool and the end face of the flange of the stopper and communicated with said valve bore through said introducing hole and also with plunger chamber means through said respective oil grooves.