US Patent 7367356 Oil flow control valve for a cam phaser

An oil flow control valve (10) for a cam phaser is described comprising a spool (18), a spool housing (16) and a check valve (40), wherein the spool (18) comprises a throughbore (60) and the check valve (40) is mounted in the spool housing (16) in that it extends through the throughbore (60) allowing the check valve (40) to be integrated in the housing (16) of the oil flow control valve (10), with the spool (18) reciprocally moving around the check valve (40), in order to avoid any influencing of the equilibrium of a spool (18) when the oil pressure is suddenly changing in the oil flow control valve (10) due to varying efforts in the cam phaser caused by the valve train.