Patent ID: 7987827

Claim:
A valve timing control apparatus for controlling valve timing of a valve that is opened and closed by a camshaft through torque transmitted from a crankshaft in an internal combustion engine, the valve timing control apparatus comprising: a first rotor that is rotatable with the crankshaft; a second rotor that is rotatable with the camshaft, wherein: the second rotor and the first rotor define therebetween an advance chamber and a retard chamber, which are circumferentially arranged one after another; the second rotor drives the camshaft with respect to the crankshaft in an advance direction when working fluid is supplied to the advance chamber; and the second rotor drives the camshaft with respect to the crankshaft in a retard direction when working fluid is supplied to the retard chamber; and a controller that includes: a supply passage, through which working fluid is supplied from an external fluid supply source; first and second drain passages, through which working fluid is discharged, wherein the controller controls a connection state of each of the supply passage and the first and second drain passages with a corresponding one of the advance chamber and the retard chamber; a spool valve that includes a spool, which is reciprocably movable, wherein: the spool valve connects the supply passage to the advance chamber and connects the first drain passage to the retard chamber by moving the spool to an advance position in order to advance a phase of the camshaft with respect to the crankshaft; and the spool valve connects the supply passage to the retard chamber and connects the second drain passage to the advance chamber by moving the spool to a retard position in order to retard the phase; at least one connection passage that connects the supply passage to a corresponding one of the first and second drain passages when the spool is moved to one of the advance position and the retard position; and at least one check valve that is provided respectively in the at least one connection passage, wherein: the at least one check valve allows working fluid to flow in a first direction from the corresponding one of the first and second drain passages toward the supply passage; and the at least one check valve limits working fluid from flowing in a second direction from the supply passage toward the corresponding one of the first and second drain passages, wherein: the at least one connection passage includes: a first connection passage that connects the supply passage to the first drain passage when the spool is moved to the advance position; and a second connection passage that connects the supply passage to the second drain passage when the spool is moved to the retard position; the first and second connection passages are defined inside the spool; and the at least one check valve includes: a first check valve that is provided in the first connection passage, inside the spool; and a second check valve that is provided in the second connection passage, inside the spool.