Patent ID: 8336510
Filing Date: 2012-12-25
Classification: F01L

Abstract:
1. A valve timing control apparatus comprising: an inner rotor rotating integrally with a camshaft for opening and closing a valve of an internal combustion engine; a vane attached to the inner rotor; an outer rotor mounted to the inner rotor so as to be relative rotatable therewith within a predetermined range and being rotated by a rotational force transmitted from a crankshaft of the internal combustion engine; a fluid pressure chamber formed at an inner portion of the outer rotor and divided into an advanced angle chamber and a retarded angle chamber by the vane; a first fluid passage formed in fluid communication with the advanced angle chamber; a second fluid passage formed in fluid communication with the retarded angle chamber; a lock mechanism used for restricting a relative rotation between the inner rotor and the outer rotor; a third fluid passage formed in fluid communication with the lock mechanism to restrict the relative rotation between the inner rotor and the outer rotor by discharging the fluid from the lock mechanism and to allow the relative rotation between the inner rotor and the outer rotor by supplying the fluid to the lock mechanism; a first switching valve for controlling a fluid flow so as to be supplied to each of the first fluid passage and the second fluid passage and so as to be discharged from each of the first fluid passage and the second fluid passage; and a second switching valve for controlling a fluid flow so as to be supplied to and discharged from the third fluid passage, wherein the first switching valve is operated independently from an operation of the second switching valve, and fluid is supplied to the first switching valve via the second switching valve, and wherein the second switching valve is switchable to a first position at which the fluid is supplied to the first switching valve and the third fluid passage and is switchable to a second position at which the fluid is discharged from the first switching valve and the third fluid passage.