Valve timing adjustment device

A valve timing adjustment device for adjusting a valve timing of a valve that is opened and closed by a camshaft with a torque transmitted from a crankshaft at an internal combustion engine, the valve timing adjustment device comprising:

• a drive-side rotor that is configured to be rotated synchronously with the crankshaft about a rotation center axis that is coaxial with the camshaft;
• a driven-side rotor that is configured to be rotated integrally with the camshaft about the rotation center axis;
• an internal gear section that is formed at one of the driven-side rotor and the drive-side rotor;
• a planetary rotor that has a planetary gear section which is eccentric to the rotation center axis and is meshed with the internal gear section;
• and
• an Oldham coupling that includes:
• a driven Oldham flange that is formed at another one of the driven-side rotor and the drive-side rotor;
• a drive Oldham flange that is formed at the planetary rotor;
• and
• an Oldham intermediate that is configured to synchronize rotation of the driven Oldham flange and rotation of the drive Oldham flange while permitting eccentricity between the driven Oldham flange and the drive Oldham flange, wherein:
• the valve timing adjustment device is configured to satisfy a relationship of θ2<θ1 where:
• θ1 is a maximum tilt amount of the planetary rotor relative to the driven Oldham flange;
• and θ2 is a maximum tilt amount of the planetary rotor in a clearance formed at the Oldham coupling.