Patent ID: 7383802

Claim:
A valve timing adjusting apparatus of an internal combustion engine, which controls valve timing of at least one of an intake valve and an exhaust valve that are opened and closed by a camshaft driven by a torque transmitted from a crankshaft at the engine, the valve timing adjusting apparatus comprising: a first gear that is rotated synchronously with one of the crankshaft and the camshaft of the engine; a second gear that is eccentric to the first gear and is meshed with the first gear to make a planetary movement, wherein the second gear includes a plurality of projections that are arranged one after another in a revolving direction of the second gear and axially project from the second gear; and a rotator that is coaxial with and is rotated relative to the first gear in response to the planetary movement of the second gear to change a relative phase between the crankshaft and the camshaft and thereby to change the valve timing of the at least one of the intake valve and the exhaust valve, wherein: the rotator includes a plurality of engaging holes, which are arranged one after another in a rotational direction of the rotator and loosely receive the plurality of projections, respectively, in such a manner that each of the plurality of projections is engageable with an inner peripheral surface of a corresponding one of the plurality of engaging holes to transmit a torque between the second gear and the rotator; and an outer peripheral surface of each of the plurality of projections has at least one reduced surface section, which is radially inwardly reduced toward a radial center of the projection along a radial line of the second gear that passes through the radial center of the projection to have a reduced radial size in comparison to a radial size of the rest of the outer peripheral surface of the projection.