Patent ID: 8789505

Claim:
A valve timing control apparatus of an internal combustion engine, comprising: a housing adapted to be driven by a crankshaft of the engine, and configured to define working-fluid chambers therein by partitioning an internal space by shoes protruding radially inward from an inner peripheral surface of the housing; a vane rotor having a rotor adapted to be fixedly connected to a camshaft and radially-extending vanes formed on an outer periphery of the rotor for partitioning each of the working-fluid chambers of the housing by the shoes and the vanes to define phase-advance hydraulic chambers and phase-retard hydraulic chambers; a lock mechanism configured to lock or unlock, depending on a condition of the engine, the vane rotor in a specified angular position between a maximum phase-retard angular position and a maximum phase-advance angular position of the vane rotor relative to the housing; and at least one recessed-groove fluid-communication passage formed in a portion of the housing being in sliding-contact with an associated one of the vanes, a circumferential length of the fluid-communication passage being dimensioned to be greater than a circumferential width of the associated vane, wherein, at the maximum phase-retard angular position of the vane rotor relative to the housing, one circumferential end of the fluid-communication passage is formed in a position further displaced from the maximum phase-retard angular position of the associated vane in a phase-retard direction to face an associated one of the phase-advance hydraulic chambers, and another circumferential end of the fluid-communication passage is formed to face an associated one of the phase-retard hydraulic chambers, or at the maximum phase-advance angular position of the vane rotor relative to the housing, one circumferential end of the fluid-communication passage is formed in a position further displaced from the maximum phase-advance angular position of the associated vane in a phase-advance direction to face the associated phase-retard hydraulic chamber and the another circumferential end of the fluid-communication passage is formed to face the associated phase-advance hydraulic chamber.