Patent ID: 7406935

Claim:
A variable valve timing control apparatus of an internal combustion engine comprising: a rotary phase-converter housing adapted to be driven by an engine crankshaft; a plate provided to hermetically cover at least one opening end of a substantially cylindrical housing portion of the housing; a five-blade vane member fixedly connected to a camshaft and rotatably disposed in the housing and having five blades spaced apart from each other in a circumferential direction of the housing; a plurality of shoes integrally formed on an inner peripheral wall of the housing portion and cooperating with the blades for defining phase-retard and phase-advance chambers; a lock piston slidably supported in a first one of the five blades, the first blade dimensioned to have a maximum circumferential width greater than the other four blades; a lock-piston hole formed in the plate for engagement with the lock piston; a coupling-and-uncoupling mechanism provided to move the lock piston into and out of engagement with the lock-piston hole, depending on an operating condition of the engine; and a positioning mechanism interposed between the plate and a predetermined part of the housing portion where an associated one of the shoes facing a sidewall of the first blade is located, for positioning a circumferential position of the lock piston in relation to the lock-piston hole.