Oil control valve for the variable valve lift system

摘要

The present invention relates to an oil control valve for a variable valve lift system that obtains in a stable manner a constant hydraulic pressure in the hydraulic line connecting the oil control valve and the vale lift control actuator, and thereby reliably controls valve lift according to the number of revolutions and load of the engine.

主权项

1. An oil control valve for a variable valve lift system, the oil control valve comprising:
a valve housing
having a cylindrical shape, andcomprising
a control port disposed in a middle portion of the valve housing, anda drain port disposed in a lower portion of the valve housing; a valve cap
joined to an upper portion of the valve housing, andcomprising an inflow port disposed in an upper surface of the valve cap; an upper seat
disposed inside the valve housing,located above the control port, andcomprising a first through-hole disposed in a center of the upper seat; a lower seat
disposed inside the valve housing,located below the control port, andcomprising a second through-hole disposed in a center of the lower seat; a ball valve
configured to
move up and down in a first chamber formed by the valve cap and the upper seat, andopen and close the first through-hole; a check valve
configured to move up and down below the lower seat, andcomprising
an upper portion protruding convexly so as to open and close the second through-hole, anda third through-hole disposed in a center of an upper surface of the check valve; a pilot
configured to move up and down inside the valve housing,comprising multi-sections such that an upper portion of the pilot has a smaller diameter than that of a lower portion of the pilot, the upper portion of the pilot configured to contact the ball valve through the first to third through-holes; a pressing spring
disposed on the upper portion of the pilot,configured to elastically push the check valve such that the upper portion of the check valve seals the second through-hole; a valve case in which the lower portion of the valve housing is inserted; a plunger
disposed
inside the valve case, andin close contact with the lower portion of the pilot; a bobbin
encircling the plunger, andcomprising a coil wound around a perimeter of the bobbin; and a yoke located between the plunger and the bobbin, wherein the check valve is configured to be elastically pushed upward by the pressing spring to seal the second through-hole to maintain residual pressure in a second chamber formed by the upper seat and the lower seat, wherein the upper seat has a greater diameter than that of the lower seat, and wherein an interior wall of the valve housing comprises a first ledge and a second ledge, the first ledge configured to receive the lower seat placed thereon, the second ledge configured to receive the upper seat placed thereon.