Patent ID: 8726867

Claim:
A phase varying apparatus having: a drive rotor driven by the crankshaft of the engine, a control rotor, a camshaft for rotatably and coaxially supporting the drive rotor, a torque provision means for providing the control rotor with a torque to rotate the control rotor relative to the drive rotor, a phase angle varying mechanism for varying the relative phase angle between the camshaft and the drive rotor in response to the rotation of the control rotor relative to the drive rotor, and a self-locking mechanism for preventing a gap in phase angle due town external disturbing cam torque from occurring between the drive rotor and the camshaft, the phase angle varying apparatus characterized in that the self-locking mechanism comprises: a cylinder section mounted on the drive rotor; a circular eccentric can integral with the camshaft; and a lock plate having a can holding groove for holding therein the circular eccentric cam, and the lock plate is provided on the periphery thereof with at least four radial abutment protrusions in smooth contact with the inner circumference of the cylinder section.